The split pickup split delivery crude oil tanker routing and scheduling problem is a difficult combinatorial optimization problem, both theoretically and practically. However, because of the large expenses in crude oil shipping it is attractive to make use of optimization that exploits as many degrees of freedom as possible to save transportation cost. We propose a nested column generation algo...

Almond harvest accounts for a significant amount of PM10 emissions in California each harvest season. This paper addresses the adjustment of sweeper depth and its effect on PM10 emissions from sweeping and pickup operations. Ambient total suspended particulate (TSP) and PM10 sampling was conducted during harvest with alternating control (proper sweeper setting) and experimental treatment (sweep...

Pickup of several molecules, H(2)O, HBr, and CH(3)OH, and Ar atoms on free Ar(N) clusters has been investigated in a molecular beam experiment. The pickup cross sections of the clusters with known mean sizes, Ñ≈ 150 and 260 were measured by two independent methods: (i) the cluster beam velocity decrease due to the momentum transfer of the picked up molecules to the clusters, and (ii) Poisson di...

Health risks posed by dermal contact with PCB-contaminated porous surfaces have not been directly demonstrated and are difficult to estimate indirectly. Surface contamination by organic compounds is commonly assessed by collecting wipe samples with hexane as the solvent. However, for porous surfaces, hexane wipe characterization is of limited direct use when estimating potential human exposure....

As we progress towards a world where robots play an integral role, a critical problem that remains to be solved is that of dynamically formed heterogeneous robot teams where little information is known a-priori about the tasks, the robots, and the environments in which they will operate. We define this challenge as the Pickup Team Challenge. Successful solutions to forming pickup teams will ena...

This article studies the double traveling salesman problem with two stacks. A number of requests have to be served where each request consists in the pickup and delivery of an item. All the pickup operations have to be performed before any delivery can take place. A single vehicle is available that starts from a depot, performs all the pickup operations and returns to the depot. Then, it perfor...

Splitting loads such that the delivery of certain loads is completed in multiple trips rather than one trip results in opportunities for a reduction in cost and the number of vehicles used. Several studies have shown the benefit of split deliveries for the Vehicle Routing Problem, in which a vehicle operating out of a depot makes a series of deliveries on each route. In this paper, we quantify ...

Today manufacturers have become much more concerned with the coordination of both manufacturing (of new products) and recycling (of reusable resources) operations. This requires simultaneous scheduling of both forward and reverse flows of goods over a supply chain network. This paper studies time dependent vehicle routing problems with simultaneous pickup and delivery (TD-VRPSPD). We formulate ...

This paper extends Vickrey’s point-queue model to study ridesharing behavior during a morning commute with uncertain bottleneck location. Unlike other cost analysis models, there are two congestion cases and four dynamic departure patterns in our model: pre-pickup case post-pickup case; both early pattern, late for pickup but work pattern. Analytical results indicate that the property of mixed ...