Biomedical subjects

M Sam Mannan

Publications and source records attributed to M Sam Mannan.

14 recordsLinked to original sources

PubMed2006

Development of a miniature calorimeter for identification and detection of explosives and other energetic compounds.

The development of versatile systems capable of providing rapid, portable, and inexpensive detection of explosives and energetic compounds are critically needed to offer enhanced levels of protection against current and future threats to homeland security, as well as satisfying a wide range of applications in the fields of forensic analysis, emergency response, and industrial hazards analysis. Calorimetric techniques have been largely overlooked in efforts to develop advanced chemical analysis technology, largely because of limitations associated with the physical size of the instruments and the relatively long timescales (>30 min) required to obtain a result. This miniaturized calorimeter circumvents these limitations, thereby creating a first-of-its-kind system allowing thermal analysis to be performed in a portable format that can be configured for use in a variety of field operations with a significantly reduced response time (approximately 2 min). Unlike current explosives detectors, this system is based on calorimetric techniques that are inherently capable of providing direct measurements of energy release potential and therefore do not depend on prior knowledge of familiar compounds.

Calorimetry↗

PubMed2006

Incident analysis of Bucheon LPG filling station pool fire and BLEVE.

An LPG filling station incident in Korea has been studied. The direct cause of the incident was concluded to be faulty joining of the couplings of the hoses during the butane unloading process from a tank lorry into an underground storage tank. The faulty connection of a hose to the tank lorry resulted in a massive leak of gas followed by catastrophic explosions. The leaking source was verified by calculating the amount of released LPG and by analyzing captured photos recorded by the television news service. Two BLEVEs were also studied.

Accidents, Occupational↗

PubMed2005

Relationship of safety culture and process safety.

Throughout history, humans have gathered in groups for social, religious, and industrial purposes. As the conglomeration of people interact, a set of underlying values, beliefs, and principles begins to develop that serve to guide behavior within the group. These "guidelines" are commonly referred to as the group culture. Modern-day organizations, including corporations, have developed their own unique cultures derived from the diversity of the organizational interests and the background of the employees. Safety culture, a sub-set of organizational culture, has been a major focus in recent years. This is especially true in the chemical industry due to the series of preventable, safety-related disasters that occurred in the late seventies and eighties. Some of the most notable disasters, during this time period, occurred at Bhopal, Flixborough, and Seveso. However, current events, like the September 11th terrorist attacks and the disintegration of the Columbia shuttle, have caused an assessment of safety culture in a variety of other organizations.

Disasters↗

PubMed2005

Assessment of the effects of release variables on the consequences of LNG spillage onto water using FERC models.

Liquefied natural gas (LNG) release, spread, evaporation, and dispersion processes are illustrated using the Federal Energy Regulatory Commission models in this paper. The spillage consequences are dependent upon the tank conditions, release scenarios, and the environmental conditions. The effects of the contributing variables, including the tank configuration, breach hole size, ullage pressure, wind speed and stability class, and surface roughness, on the consequence of LNG spillage onto water are evaluated using the models. The sensitivities of the consequences to those variables are discussed.

Accidents↗

PubMed2005

Harnessing data mining to explore incident databases.

Large numbers of incident related databases have been established in the last three decades. The majority of attempts to explore these data marts were trials to identify patterns via first glance into the datasets. This study investigated a subset of incidents from fixed facilities in Harris County, TX, extracted from the National Response Center database. By classifying the information into groups and using data mining techniques, interesting patterns of incidents according to characteristics such as type of equipment involved, type of chemical released and causes involved were revealed and further these were used to modify the annual failure probabilities of equipments.

Chemical Industry↗

PubMed2005

Sensor fault diagnosis for nonlinear processes with parametric uncertainties.

This paper addresses the problem of detecting, discriminating, and reconstructing sensor faults for nonlinear systems with known model structure but uncertainty in the parameters of the process. The convenience of the proposed technique lies in the fact that historical operational data and/or a priori fault information is not required to achieve accurate fault reconstruction except for fixed, short intervals. The overall fault diagnosis algorithm is composed of a series of nonlinear estimators, which estimates parameter and a fault isolation and identification filter. Parameter estimation and fault reconstruction cannot be performed accurately since faults and parametric uncertainty interact with each other. Therefore, these two tasks are performed at different time scales, where the fault diagnosis takes place at a more frequent rate than the parameter estimation. It is shown that the fault can be reconstructed under some realistic assumptions and the performance of the proposed methodology is evaluated on a simulated chemical process exhibiting nonlinear dynamic behavior.

Algorithms↗

PubMed2005

Thermal decomposition hazard evaluation of hydroxylamine nitrate.

Hydroxylamine nitrate (HAN) is an important member of the hydroxylamine family and it is a liquid propellant when combined with alkylammonium nitrate fuel in an aqueous solution. Low concentrations of HAN are used primarily in the nuclear industry as a reductant in nuclear material processing and for decontamination of equipment. Also, HAN has been involved in several incidents because of its instability and autocatalytic decomposition behavior. This paper presents calorimetric measurement for the thermal decomposition of 24 mass% HAN/water. Gas phase enthalpy of formation of HAN is calculated using both semi-empirical methods with MOPAC and high-level quantum chemical methods of Gaussian 03. CHETAH is used to estimate the energy release potential of HAN. A Reactive System Screening Tool (RSST) and an Automatic Pressure Tracking Adiabatic Calorimeter (APTAC) are used to characterize thermal decomposition of HAN and to provide guidance about safe conditions for handling and storing of HAN.

Calorimetry↗

PubMed2004

Initial perspectives on process threat management.

Terrorist and criminal acts are now considered credible risks in the process industries. Deliberate attacks on the nation's petroleum refineries and chemical plants would pose a significant threat to public welfare, national security, and the US economy. To-date, the primary response of government and industry has been on improved security to prevent attacks and the associated consequences. While prevention is clearly preferred, the potential for successful attacks must be addressed. If plant security is breached, the extent of the inflicted damage is determined by the available plant safety systems and procedures. We refer to this "inside the gate" response as process threat management. The authors have initiated a joint industry/academia study to address: the level of safety provided by existing plant equipment and safety systems in response to a terrorist act, and identification of process (rather than security) needs or opportunities to address this new safety concern. This paper describes the initial perspectives and issues identified by the team at the beginning of the study.

Chemical Industry↗

PubMed2004

Making the business case for process safety using value-at-risk concepts.

An increasing emphasis on chemical process safety over the last two decades has led to the development and application of powerful risk assessment tools. Hazard analysis and risk evaluation techniques have developed to the point where quantitatively meaningful risks can be calculated for processes and plants. However, the results are typically presented in semi-quantitative "ranked list" or "categorical matrix" formats, which are certainly useful but not optimal for making business decisions. A relatively new technique for performing valuation under uncertainty, value at risk (VaR), has been developed in the financial world. VaR is a method of evaluating the probability of a gain or loss by a complex venture, by examining the stochastic behavior of its components. We believe that combining quantitative risk assessment techniques with VaR concepts will bridge the gap between engineers and scientists who determine process risk and business leaders and policy makers who evaluate, manage, or regulate risk. We present a few basic examples of the application of VaR to hazard analysis in the chemical process industry.

Chemical Industry↗

PubMed2003

The use of aerosol formation, flammability, and explosion information for heat-transfer fluid selection.

The devastating consequences of aerosol/mist explosions have been widely documented, and there are currently efforts to understand the mechanisms of formation and explosion of aerosols. Heat-transfer fluids (HTFs) are particularly susceptible to these hazards, because they are utilized under high pressures and below their flash points, making them more prone to leaking as aerosols. In fact, there is a critical need during design stages for a perception of explosion risks associated with the selection of HTFs. This paper discusses a novel scheme to integrate the knowledge of HTF aerosol formation from leaks in process equipment into the selection of HTFs during the design process. Hazards of aerosols formed from leaks are classified qualitatively using process pressure and droplet sizes.

Aerosols↗

PubMed2003

Prevention and suppression of metal packing fires.

Structured packing has been widely used because of large surface area that makes possible columns with high capacity and efficiency. The large surface area also contributes to fire hazards because of hydrocarbon deposits that can easily combust and promote combustion of the thin metal packing materials. Materials of high surface area that can fuel fires include reactive metals, such as titanium, and materials that are not considered combustible, such as stainless steel. Column design and material selection for packing construction is discussed together with employee training and practices for safe column maintenance and operations. Presented also are methods and agents for suppression of metal fires. Guidance for prevention and suppression of metal fires is related to incidents involving packing fires in columns.

Explosions↗

PubMed2003

Using screening test data to recognize reactive chemical hazards.

The evaluation of reactive hazards is necessary for safe operations in the chemical process industries. An integral aspect of reactive hazard testing is the screening of chemicals to focus experimental efforts on the more hazardous chemicals. Screening is often performed using a Differential Scanning Calorimeter (DSC) or the Reactive System Screening Tool (RSST). The study of chemical incompatibility highlights the need for efficient screening techniques, since a large number of experiments must be performed at a reasonable cost and in a short period of time. A purpose of this paper is to present chemical incompatibility data measured using the RSST for di-tert-butyl peroxide (DTBP) in a variety of organic solvents. Analysis of the data with regard to the solvent functional groups was generalized to extend the measured data to compounds for which data are unavailable. Further, a classification for reactive chemicals is proposed that can serve as a guideline for selecting compositions for detailed testing.

Chemical Industry↗

PubMed2003

Fault detection and classification in chemical processes based on neural networks with feature extraction.

Feed forward neural networks are investigated here for fault diagnosis in chemical processes, especially batch processes. The use of the neural model prediction error as the residual for fault diagnosis of sensor and component is analyzed. To reduce the training time required for the neural process model, an input feature extraction process for the neural model is implemented. An additional radial basis function neural classifier is developed to isolate faults from the residual generated, and results are presented to demonstrate the satisfactory detection and isolation of faults using this approach.

Algorithms↗

PubMed2003

Correlation of quantitative risk results for high hazard processes.

A quantitative risk analysis was conducted to evaluate the design of the VX neutralization subsystem and related support facilities of the U.S. Army Newport Chemical Agent Disposal Facility. Three major incidents including agent release, personnel injury, and system loss were studied using fault tree analysis methodology. Each incident was assigned a risk assessment code based on the severity level and probability of occurrence of the incident. Safety mitigations or design changes were recommended to bring the "undesired" risk level (typical agent release events) to be "acceptable with controls" or "acceptable."

Chemical Warfare Agents↗