Study of a Dynamic Cooperative Trading Queue Routing Control Scheme for Freeways and Facilities with Parallel Queues

This article explores the coalitional stability of a new cooperative control policy for freeways and parallel queuing facilities with multiple servers. Based on predicted future delays per queue or lane, a VOT-heterogeneous population of agents can agree to switch lanes or queues and transfer payments to each other in order to minimize the total cost of the incoming platoon. The strategic interaction is captured by an n-level Stackelberg model with coalitions, while the cooperative structure is formulated as a partition function game (PFG). The stability concept explored is the strong-core for PFGs which we found appropiate given the nature of the problem. This concept ensures that the efficient allocation is individually rational and coalitionally stable. We analyze this control mechanism for two settings: a static vertical queue and a dynamic horizontal queue. For the former, we first characterize the properties of the underlying cooperative game. Our simulation results suggest that the setting is always strong-core stable. For the latter, we propose a new relaxation program for the strong-core concept. Our simulation results on a freeway bottleneck with constant outflow using Newell's car-following model show the imputations to be generally strong-core stable and the coalitional instabilities to remain small with regard to users' costs.Comment: 3 figures. Presented at Annual Meeting Transportation Research Board 2018, Washington DC. Proof of conjecture 1 pendin

Early-age Fracture Response of Concrete with Hybrid Steel and Macro-synthetic Polypropylene Fiber Blends

Concrete is the most widely used construction material as it offers low cost, general availability, and wide applicability. Concrete being a quasi-brittle material and it exhibits an increase in brittleness with increasing strength. Plain concrete has low tensile strength and toughness. Failure in concrete under applied tensile loading is associated with cracking. A crack is produced at low tensile stress and once formed it grows rapidly in the material. Concrete in the hardening state (after setting) develops tensile stress if volume changes due to shrinkage and thermal strains are restrained. Damage in tension develops at low tensile stress in the form of microcracks. The microcracks are formed even before the application of load. Under applied load, these micro-cracks coalesce to form visible cracks. Cracking leads to premature deterioration often resulting in a dramatic reduction in the service life and an increase in the life-cycle maintenance costs; cracks also accelerate deterioration by permitting the ingress of aggressive agents thereby producing corrosion of the steel reinforcement. Therefore improving the ability of concrete to carry tensile stresses is important to improve the service performance of structures

Impact of Seasonal Changes on Water Characterstics at Palakkad in 2021-2022

Geometric increase in population coupled with rapid urbanization, industrialization and agricultural development has resulted in high impact on quality and quantity of water in India. Hence, the availability and the quality of the freshwater resources are the most pressing of the many environmental challenges in India (CPCB 2011). The quality of water is of vital concern for mankind, since it is directly linked with human welfare. Poor quality of water adversely affects the plant growth and human health (WHO 1984; Hem 1985). A number of studies on water quality have been carried out in different parts of India All these studies reveal that both rivers and groundwater in India are facing water quality issues. The state of Kerala, located in the south-western corner of India, is blessed with 44 rivers and heavy rainfall of ~ 3000 mm/year. However, most of the water in the rivers is quickly drained into the Arabian Sea due to the steep seaward sloping of the state. Hence, in addition to rivers, the groundwater is also utilized to meet the water requirements of the state. The increase in population, development activities, urbanization, change in land-use pattern, etc. has created a concern among the people of Kerala regarding both the river water and groundwater quality of various river basins

Stress-Crack Separation Relationship for Macrosynthetic, Steel and Hybrid Fiber Reinforced Concrete

An experimental evaluation of the crack propaga tion and post-cracking response of macro fiber reinforced concrete in flexure is c onducted. Two types of structur al fibers, hooked end steel fibers and continuousl y embossed macro-synthetic fibers are used in this study. A fiber blend of the two fibers is evaluated for spec ific improvements in the post peak residual load carrying response. At 0.5% volume fraction, both steel and macrosynthetic fiber reinforced concrete exhibits load recovery at large crack opening. The blend of 0.2% macrosynthetic fibers and 0.3% steel fibers shows a significa nt improvement in the immediate post peak load response with a significantly smaller load drop and a constant residual load carrying capacity equal to 80% of the peak load. An analytical formulation to predict fle xure load-displacement behaviour considering a multi-linear stress- crack separation (σ -w) relationship is developed. An inverse analysis is developed for obtaining the multi- linear σ -w relation, from the experimental response. The � -w curves of the steel and macrosynthetic fiber reinforced concrete exhibit a stress recovery after a significant drop with increa sing crack opening. Significant residual load carrying capacity is attained only at large crack separation. The fiber blend exhibits a constant residual stress with increasing crack sepa ration following an initial decrease. The constant residual stress is attained at a small crack separation

Dynamic Modeling and Real-time Management of a System of EV Fast-charging Stations

Demand for electric vehicles (EVs), and thus EV charging, has steadily increased over the last decade. However, there is limited fast-charging infrastructure in most parts of the world to support EV travel, especially long-distance trips. The goal of this study is to develop a stochastic dynamic simulation modeling framework of a regional system of EV fast-charging stations for real-time management and strategic planning (i.e., capacity allocation) purposes. To model EV user behavior, specifically fast-charging station choices, the framework incorporates a multinomial logit station choice model that considers charging prices, expected wait times, and detour distances. To capture the dynamics of supply and demand at each fast-charging station, the framework incorporates a multi-server queueing model in the simulation. The study assumes that multiple fast-charging stations are managed by a single entity and that the demand for these stations are interrelated. To manage the system of stations, the study proposes and tests dynamic demand-responsive price adjustment (DDRPA) schemes based on station queue lengths. The study applies the modeling framework to a system of EV fast-charging stations in Southern California. The results indicate that DDRPA strategies are an effective mechanism to balance charging demand across fast-charging stations. Specifically, compared to the no DDRPA scheme case, the quadratic DDRPA scheme reduces average wait time by 26%, increases charging station revenue (and user costs) by 5.8%, while, most importantly, increasing social welfare by 2.7% in the base scenario. Moreover, the study also illustrates that the modeling framework can evaluate the allocation of EV fast-charging station capacity, to identify stations that require additional chargers and areas that would benefit from additional fast-charging stations

Stabilization of Black Cotton Soil using Lime, Coir Fiber & Rice Husk

Because of their low bearing capacity, the expansive black cotton soils' high swelling and shrinking characteristics have posed numerous challenges to construction projects. When subjected to varying levels of moisture, black cotton soil expands and contracts rapidly. As a result, stabilising the soil is necessary to address these issues. Rice Husk Ash (RHA), Cori Fiber, and Lime are being tested in this study to see if they can act as a stabilising material in the expansive black cotton soil. The impact of RHA, CF, and LIME on the expansive soil's index and engineering properties was studied in the lab. Coir fibre concentration is 1.5 percent, lime is 5 percent by weight of dry soil, and RHA is mixed in at a ratio of 20 percent. The virgin soil sample is first tested for specific gravity and grain size distribution. With and without these admixtures soil's index properties like its plastic limit, liquid limit and shrinkage limit and its strength properties like its California Bearing Ratio, Unconfined Compressive Strength tests are discovered. According to the test results, a combination of 5 percent lime and 1.5 percent coir fibre yielded the strongest soil and best index properties

Assessment of Carbon Storage and Biomass on Minelands Reclaimed to Grassland Environments Using Landsat Spectral Indices

This study investigated carbon (C) storage and biomass in grasslands of West Virginia reclaimed surface minesites. Mine-related disturbance and subsequent reclamation may be an important component of C cycling. Biomass and C storage generally increased for the first five years after reclamation, but then declined, suggesting a nonlinear pattern to vegetation recovery. Three 2007 Landsat 5 Thematic Mapper and Landsat 7 Enhanced Thematic Mapper Plus images were used to assess the potential to predict biomass from raw red and near infrared radiance, the tasseled cap transformation (TC), and four vegetation indices [normalized difference vegetation index, enhanced vegetation index (EVI), triangular vegetation index, and the soil adjusted vegetation index]. TC greenness and EVI were most strongly correlated with biomass and illustrate a modest potential for monitoring vegetation recovery in reclaimed minelands. Additionally, a number of regression models that included age since reclamation and spectral indices were statistically significant suggesting a temporal recovery pattern amongst minesites in this study