We develop a model to determine the optimal structure and size of a rail car fleet at a chemical company under uncertainty in demand and travel times as well as substitution between rail car types. First, we formulate an MILP model that accounts for the substitution relations between the types and minimizes the total direct rail car cost under given rail car availability constraints and a prede...

If your irrigation system is not performing as efficiently as you would like then it may be time to consider updating. This can be done by renewing sprinklers, installing a more advanced control panel, renewing that worn out pump — or a complete redesign of the whole system using modern technology. If you already have Weather-matic equipment installed, Prime offers a full repair and maintenance...

In This Issue In This Issue Ready…set…fuse he fusion of two lipid membranes underlies a huge range of biological phenomena, from infection by enveloped viruses to the secretion of cellular proteins , but a central aspect of membrane fusion has remained mysterious: do the T proteins that mediate fusion act cooperatively or independently? On page 833, Markovic et al. argue that teamwork is the or...

Given a flight schedule, which is a set of flight segments with specified departure and arrival times, and a set of aircraft:, the fleet assignment problem is to determine which aircraft type should fly each flight segment. The objective is to maximize revenue minus operating costs. In the basic fleet assignment problem considered by Hane et al. (1995) a daily, domestic fleet assignment prohlem...

The growth of AVL (Automatic Vehicle Location) systems leads to huge amount of data about different parts of bus fleet (buses, stations, passenger, etc.) which is very useful to improve bus fleet efficiency. In addition, by processing fleet and passengers’ historical data it is possible to detect passenger’s behavioral patterns in different parts of the day and to use it in order to improve fle...

In this paper we present a local search heuristic method for an integrated airline scheduling, fleeting and pricing model. The integrated model simultaneously optimizes the decisions of schedule design, fleet assignment, seat allocation, pricing and considers passengers’ spill and recapture. The resulting problem is a mixed integer non-convex problem due to the explicit representation of a dema...

A microscale emission factor model (MicroFacPM) for predicting real-time site-specific motor vehicle particulate matter emissions was presented in the companion paper titled "Development of a Microscale Emission Factor Model for Particulate Matter (MicroFacPM) for Predicting Real-Time Motor Vehicle Emissions". The emission rates discussed are in mass per unit distance with the model providing e...

OBJECTIVES In the year 2000, as part of the process for setting New Zealand road safety targets, a projection was made for a reduction in social cost of 15.5 percent associated with improvements in crashworthiness, which is a measure of the occupant protection of the light passenger vehicle fleet. Since that document was produced, new estimates of crashworthiness have become available, allowing...

The paper refers to the importance of maintenance management to increase the vehicle fleet energy efficiency. The fleet maintenance management influences as the vehicle maintenance process itself as well as the primary transport process but also their environment. In order to increase fleet energy efficiency by means of a more efficient maintenance management, it is indispensable to observe mai...

BACKGROUND There are no international rules regarding which medical supplies to bring when the nurseon- duty is called to emergencies outside a cruise ship's infirmary. Ideally, one First Response Bag should contain all that is needed to manage the initial 10-15 minutes of any medical emergency until the patient can be safely transported to the ship's infirmary. Royal Caribbean Cruises Ltd rece...