Upper limits for undetected trace species in the stratosphere of Titan

In this paper we describe a first quantitative search for several molecules in Titan's stratosphere in Cassini CIRS infrared spectra. These are: ammonia (NH3), methanol (CH3OH), formaldehyde (H2CO), and acetonitrile (CH3CN), all of which are predicted by photochemical models but only the last of which observed, and not in the infrared. We find non-detections in all cases, but derive upper limits on the abundances from low-noise observations at 25{\deg}S and 75{\deg}N. Comparing these constraints to model predictions, we conclude that CIRS is highly unlikely to see NH3 or CH3OH emissions. However, CH3CN and H2CO are closer to CIRS detectability, and we suggest ways in which the sensitivity threshold may be lowered towards this goal.Comment: 11 pages plus 6 figure file

Global Supply Chain Management at Digital Equipment Corporation

Interfaces, 25, pp. 69-93. (Nominated for the 1994 International Management Science Achievement Award.)Digital Equipment Corporation evaluates global supply chain alternatives and determines worldwide manufacturing and distribution strategy, using the Global Supply Chain Model (GSCM) which recommends a production, distribution, and vendor network,, GSCM minimizes cost or weighted cumulative production and distribution times or both subject to meeting estimated demand and restrictions on local content, offset trade, and joint capacity for multiple products, echelons, and time periods.Cost factors include fixed and variable production charges, inventory charges, distribution expenses via multiple modes, taxes, duties, and duty drawback. GSCM is a large mixed-integer linear program that incorporates a global, multiproduct bill of materials for supply chains with arbitrary echelon structure and comprehensive model of integrated global manufacturing and distribution decisions. The supply chain restructuring has saved over $100 million (US)