MHD oxidant intermediate temperature ceramic heater study

The use of three types of directly fired ceramic heaters for preheating oxygen enriched air to an intermediate temperature of 1144K was investigated. The three types of ceramic heaters are: (1) a fixed bed, periodic flow ceramic brick regenerative heater; (2) a ceramic pebble regenerative heater. The heater design, performance and operating characteristics under conditions in which the particulate matter is not solidified are evaluated. A comparison and overall evaluation of the three types of ceramic heaters and temperature range determination at which the particulate matter in the MHD exhaust gas is estimated to be a dry powder are presented

Common-Cause Failure Treatment in Event Assessment: Basis for a Proposed New Model

Event assessment is an application of probabilistic risk assessment in which observed equipment failures and outages are mapped into the risk model to obtain a numerical estimate of the event’s risk significance. In this paper, we focus on retrospective assessments to estimate the risk significance of degraded conditions such as equipment failure accompanied by a deficiency in a process such as maintenance practices. In modeling such events, the basic events in the risk model that are associated with observed failures and other off-normal situations are typically configured to be failed, while those associated with observed successes and unchallenged components are assumed capable of failing, typically with their baseline probabilities. This is referred to as the failure memory approach to event assessment. The conditioning of common-cause failure probabilities for the common cause component group associated with the observed component failure is particularly important, as it is insufficient to simply leave these probabilities at their baseline values, and doing so may result in a significant underestimate of risk significance for the event. Past work in this area has focused on the mathematics of the adjustment. In this paper, we review the Basic Parameter Model for common-cause failure, which underlies most current risk modelling, discuss the limitations of this model with respect to event assessment, and introduce a proposed new framework for common-cause failure, which uses a Bayesian network to model underlying causes of failure, and which has the potential to overcome the limitations of the Basic Parameter Model with respect to event assessment

Westinghouse Reactor Protection System Unavailability, 1984--1995

An analysis was performed of the safety-related performance of the reactor protection system (RPS) at U. S. Westinghouse commercial reactors during the period 1984 through 1995. RPS operational data were collected from the Nuclear Plant Reliability Data System and Licensee Event Reports. A risk-based analysis was performed on the data to estimate the observed unavailability of the RPS, based on a fault tree model of the system. Results were compared with existing unavailability estimates from Individual Plant Examinations and other reports

Decomposing the effect of supplier development on relationship benefits: The role of relational capital

Buyers invest considerably in developing their suppliers, yet the performance effects of such investments are not universal. Drawing on social capital theory, this research investigates whether the relationship between supplier development and relationship benefits may be facilitated by the generation of relational capital. The authors examine mediating and moderating roles of relational capital in the relationship between two aspects of supplier development (capability development, supplier governance) and two dimensions of relationship benefits (supplier benefits, buyer benefits), using survey data collected from 185 suppliers of a large manufacturing firm. Investment in supplier development does not automatically result in benefits for the supplier or reciprocated benefits for the buyer. Rather, relational capital "bridges" supplier development and relationship benefits. Without relational capital, benefits from capability development do not accrue, and the impact of a supplier governance regime can be even detrimental. In conditions of high relational capital, capability development results in lower perceived buyer benefits. The results can help managers ensure that the benefits from their supplier development efforts fully materialize

Managing the IE (Industrial Engineering) Mindset: A quantitative investigation of Toyota’s practical thinking shared among employees

Purpose: The goal of this work was to investigate the managerial practices of today to understand if Toyota is sheltering themselves from these newer practices or embracing them like most believe. Design/methodology/approach: This work utilizes a new form of data mining named Latent Semantic Analysis (LSA) to analyze an organizations ideal management practices. Findings: This work shows quantitatively that TPS favors earlier versions of industrial engineering compared to the optimization techniques available today. Originality/value: The use of data mining to analyze organizational management practicesPeer Reviewe

Managing the IE (Industrial Engineering) Mindset: A quantitative investigation of Toyota’s practical thinking shared among employees

Purpose: The goal of this work was to investigate the managerial practices of today to understand if Toyota is sheltering themselves from these newer practices or embracing them like most believe. Design/methodology/approach: This work utilizes a new form of data mining named Latent Semantic Analysis (LSA) to analyze an organizations ideal management practices. Findings: This work shows quantitatively that TPS favors earlier versions of industrial engineering compared to the optimization techniques available today. Originality/value: The use of data mining to analyze organizational management practice

Evaluation of thermal energy storage materials for advanced compressed air energy storage systems

Advanced Compressed-Air Energy Storage (ACAS) plants have the near-term potential to reduce the fuel consumption of compressed-air plants from 33 to 100%, depending upon their design. Fuel is saved by storing some or all of the heat of compression as sensible heat which is subsequently used to reheat the compressed air prior to expansion in the turbine generator. The thermal storage media required for this application must be low cost and durable. The objective of this project was to screen thermal store materials based on their thermal cycle durability, particulate formation and corrosion resistant characteristics. The materials investigated were iron oxide pellets, Denstone pebbles, cast-iron balls, and Dresser basalt rock. The study specifically addressed the problems of particle formation and thermal ratcheting of the materials during thermal cycling and the chemical attack on the materials by the high temperature and moist environment in an ACAS heat storage bed. The results indicate that from the durability standpoint Denstone, cast iron containing 27% or more chromium, and crushed Dresser basalt would possibly stand up to ACAS conditions. If costs are considered in addition to durability and performance, the crushed Dresser basalt would probably be the most desirable heat storage material for adiabatic and hybrid ACAS plants, and more in-depth longer term thermal cycling and materials testing of Dresser basalt is recommended. Also recommended is the redesign and costing analysis of both the hybrid and adiabatic ACAS facilities based upon the use of Dresser basalt as the thermal store material