Supply chain disruptions : managing risks vs. managing crises

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (leaves 74-76).This thesis looks at two back-to-back disruptive supply chain events, one due to a sole-supplier's bankruptcy and the other caused by Hurricane Rita, that occurred at a specialty chemical company, and uses these examples to demonstrate how managing crises is more costly than managing risks. In examining the events surrounding the sole-supplier bankruptcy, managing a crisis cost this specialty chemical company 45% more money than managing a risk. Through the findings of these two disruptive events, a framework, the Eye of Providence, is created to manage supply chain risks. First, an organization must determine how developed its risk-management protocol is. Next, by studying past disruptive events and determining the key impact factors, an organization could calculate and learn about the opportunity cost of managing crisis. Then, by continuously evaluating its suppliers and rigorously applying those key impact factors to the analysis of its supply chain practice, an organization could evaluate and identify its current vulnerabilities.(cont.) Finally, by proactively monitoring event-based warning signals, or disruption indicators, an organization could assess its potential supply chain risks, and plan accordingly. Whether a company is low on the risk-maturity level or has already integrated risk management into its corporate culture, the process developed in this thesis serves as a versatile tool that can help businesses structure a more dynamic, resilient supply chain.by Garrett J. Lee [and] Zen-Lee M. Chang.M.Eng.in Logistic

Biological Invasions: The Case of Soybean Aphid Infestation

Soybeans, the second highest cash crop following corn in the U.S., have come under attack by invasive species, the soybean aphid from the North and soybean rust from the South. We estimated the economic losses resulting from soybean aphid infestation by using a dynamic equilibrium model. Results indicate that, first, the reduction of soybean production resulting from soybean aphid infestation is largely absorbed by reducing soybean exports, due to the higher price elasticity of export demand compared to the domestic demand. Second, the economic losses to U.S. soybean producers would grow on average annually between $12.8 million and$23.4 million during the first five years of infestation. In the longer-run, soybean producers would suffer greater economic losses as the dispersion rate of infested soybean acreage with soybean aphids rises. However, the successful discovery of the soybean aphid gene (TF04048) Rag-1 (which confers resistance) does not at this time warrant soybean growers and policy-makers becoming too seriously alarmed. Even so, time is an important factor in the eventual control of the soybean aphid.Crop Production/Industries,

Economic Impacts of the U.S. Soybean Aphid Infestation: A Multi-Regional Competitive Dynamic Analysis

We estimated the economic benefits resulting from controlling soybean aphid infestation by using a multi-regional competitive dynamic equilibrium model. Results indicate that the reduction of soybean production resulting from a soybean aphid infestation is largely absorbed by reducing soybean exports, due to the higher price elasticity of export demand compared to domestic demand. Producer benefits resulting from controlling soybean aphids would increase by between $949 million and$1.623 billion in ten years under various scenarios. Results also suggest that it is economically more efficient to control soybean aphids when the rate of intrinsic growth is relatively lower, the supply price elasticity of soybean acreage is relatively more elastic, and insecticide treatment costs per acre are lower. However, if the discovery of the gene Rag-1 (TF04048) leads to new cultivars that withstand the soybean aphid, our estimates will overestimate the actual damages. Even so, our analysis demonstrates that it is critical to control soybean aphids early in their infestation cycle to avoid a rapid increase in damages.soybean aphid, invasive species, producer surplus, consumer surplus, Rag-1, Crop Production/Industries,

CFD MODELING AND ANALYSIS FOR A-AREA AND H-AREA COOLING TOWERS

Mechanical draft cooling towers are designed to cool process water via sensible and latent heat transfer to air. Heat and mass transfer take place simultaneously. Heat is transferred as sensible heat due to the temperature difference between liquid and gas phases, and as the latent heat of the water as it evaporates. Mass of water vapor is transferred due to the difference between the vapor pressure at the air-liquid interface and the partial pressure of water vapor in the bulk of the air. Equations to govern these phenomena are discussed here. The governing equations are solved by taking a computational fluid dynamics (CFD) approach. The purpose of the work is to develop a three-dimensional CFD model to evaluate the flow patterns inside the cooling tower cell driven by cooling fan and wind, considering the cooling fans to be on or off. Two types of the cooling towers are considered here. One is cross-flow type cooling tower located in A-Area, and the other is counterflow type cooling tower located in H-Area. The cooling tower located in A-Area is mechanical draft cooling tower (MDCT) consisting of four compartment cells as shown in Fig. 1. It is 13.7m wide, 36.8m long, and 9.4m high. Each cell has its own cooling fan and shroud without any flow communications between two adjacent cells. There are water distribution decks on both sides of the fan shroud. The deck floor has an array of about 25mm size holes through which water droplet falls into the cell region cooled by the ambient air driven by fan and wind, and it is eventually collected in basin area. As shown in Fig. 1, about 0.15-m thick drift eliminator allows ambient air to be humidified through the evaporative cooling process without entrainment of water droplets into the shroud exit. The H-Area cooling tower is about 7.3 m wide, 29.3 m long, and 9.0 m high. Each cell has its own cooling fan and shroud, but each of two corner cells has two panels to shield wind at the bottom of the cells. There is some degree of flow communications between adjacent cells through the 9-in gap at the bottom of the tower cells as shown in Fig. 2. Detailed geometrical dimensions for the H-Area tower configurations are presented in the figure. The model was benchmarked and verified against off-site and on-site test results. The verified model was applied to the investigation of cooling fan and wind effects on water cooling in cells when fans are off and on. This report will discuss the modeling and test results

The Cdc37 protein kinase–binding domain is sufficient for protein kinase activity and cell viability

Cdc37 is a molecular chaperone required for folding of protein kinases. It functions in association with Hsp90, although little is known of its mechanism of action or where it fits into a folding pathway involving other Hsp90 cochaperones. Using a genetic approach with Saccharomyces cerevisiae, we show that CDC37 overexpression suppressed a defect in v-Src folding in yeast deleted for STI1, which recruits Hsp90 to misfolded clients. Expression of CDC37 truncation mutants that were deleted for the Hsp90-binding site stabilized v-Src and led to some folding in both sti1Δ and hsc82Δ strains. The protein kinase–binding domain of Cdc37 was sufficient for yeast cell viability and permitted efficient signaling through the yeast MAP kinase–signaling pathway. We propose a model in which Cdc37 can function independently of Hsp90, although its ability to do so is restricted by its normally low expression levels. This may be a form of regulation by which cells restrict access to Cdc37 until it has passed through a triage involving other chaperones such as Hsp70 and Hsp90

Products and Process Modeling in Cx: A Significant Challenge for Digital-Cx

In the next decade, digitalization of commissioning (Cx) is likely to be a key advance, in the field of AEC. This requires that as much of what we do manually, through word processing and spreadsheets can be done through sophisticated computer applications to enhance Cx productivity. The first step in achieving this is the creation of reliable, persistent, accurate, just-in-time, and easily accessible Cx information. Towards this end we are building a proof-of-concept prototype for functional performance tests (FPT) that can help Cx agents derive product models through specifying process descriptions

Search for Intrinsic Excitations in 152Sm

The 685 keV excitation energy of the first excited 0+ state in 152Sm makes it an attractive candidate to explore expected two-phonon excitations at low energy. Multiple-step Coulomb excitation and inelastic neutron scattering studies of 152Sm are used to probe the E2 collectivity of excited 0+ states in this "soft" nucleus and the results are compared with model predictions. No candidates for two-phonon K=0+ quadrupole vibrational states are found. A 2+, K=2 state with strong E2 decay to the first excited K=0+ band and a probable 3+ band member are established.Comment: 4 pages, 6 figures, accepted for publication as a Rapid Communication in Physical Review

Ontology Development for Low-Energy Building Embedded Commissioning

This paper presents the results of initial work in developing an ontology for improving information exchange and automation in building system commissioning practices. In our previous research dealing with the derivation of product models from building commissioning process models, we found that there is a need to categorize and classify information items, which are available in commissioning process descriptions. In addition, the relationship between these items should be clearly defined to establish a topological relationship between items necessary for specifying product models. Ontology development is the way to categorize and classify domain knowledge information and items into inter-related concepts. Ontology assembles information in the form of concept hierarchies (taxonomies), axioms, and semantic relationships, which allow natural language to be presented unambiguously. A glossary (a lower form of ontology) specific to building commissioning tasks was developed as a first step. In the second step, an ontology for use in commissioning software applications was developed

The Identity of Proteins Associated with a Small Heat Shock Protein during Heat Stress \u3ci\u3ein Vivo\u3c/i\u3e Indicates That These Chaperones Protect a Wide Range of Cellular Functions

The small heat shock proteins (sHSPs) are a ubiquitous class of ATP-independent chaperones believed to prevent irreversible protein aggregation and to facilitate subsequent protein renaturation in cooperation with ATP-dependent chaperones. Although sHSP chaperone activity has been studied extensively in vitro, understanding the mechanism of sHSP function requires identification of proteins that are sHSP substrates in vivo. We have used both immunoprecipitation and affinity chromatography to recover 42 proteins that specifically interact with Synechocystis Hsp16.6 in vivo during heat treatment. These proteins can all be released from Hsp16.6 by the ATP-dependent activity of DnaK and cochaperones and are heat-labile. Thirteen of the putative substrate proteins were identified by mass spectrometry and reveal the potential for sHSPs to protect cellular functions as diverse as transcription, translation, cell signaling, and secondary metabolism. One of the putative substrates, serine esterase, was purified and tested directly for interaction with purified Hsp16.6. Hsp16.6 effectively formed soluble complexes with serine esterase in a heat-dependent fashion, thereby preventing formation of insoluble serine esterase aggregates. These data offer critical insights into the characteristics of native sHSP substrates and extend and provide in vivo support for the chaperone model of sHSP function