The Experts below are selected from a list of 87 Experts worldwide ranked by ideXlab platform
David J. Smith - One of the best experts on this subject based on the ideXlab platform.
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Chapter 24 – A case study: Gas Detection System
Reliability Maintainability and Risk, 2020Co-Authors: David J. SmithAbstract:Publisher Summary This chapter presents a case study based on a typical gas detection system and it provides an example of the safety-integrity targeting. Assume that the gas detection system has the primary function of providing an executive action input to some other emergency shutdown (ESD) system in order to protect a chemical process plant. This ESD system will close valves to isolate the flammable gases so as to prevent subsequent explosion or fire. It is assumed that successful operation of the gas detection and ESD system will prevent fatality. In order to establish a safety-integrity target, it is necessary to establish a Maximum Tolerable failure rate for the safety-related system. If a Maximum Tolerable failure rate is to be established then, a Maximum Tolerable Risk of fatality must first be stated. Mathematical expressions are given that show the Maximum Tolerable failure rate and Maximum Tolerable probability of failure on demand for the particular event.
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A case study: Gas Detection System
Reliability Maintainability and Risk, 2020Co-Authors: David J. SmithAbstract:This chapter presents a case study based on a typical gas detection system and it provides an example of the safety-integrity targeting. Assume that the gas detection system has the primary function of providing an executive action input to some other emergency shutdown (ESD) system in order to protect a chemical process plant. This ESD system will close valves to isolate the flammable gases so as to prevent subsequent explosion or fire. It is assumed that successful operation of the gas detection and ESD system will prevent fatality. In order to establish a safety-integrity target, it is necessary to establish a Maximum Tolerable failure rate for the safety-related system. If a Maximum Tolerable failure rate is to be established then, a Maximum Tolerable Risk of fatality must first be stated. Mathematical expressions are given that show the Maximum Tolerable failure rate and Maximum Tolerable probability of failure on demand for the particular event.
Christopher R. Clarke - One of the best experts on this subject based on the ideXlab platform.
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SmartGridComm - Optimal design of hybrid energy system with PV/wind turbine/storage: A case study
2011 IEEE International Conference on Smart Grid Communications (SmartGridComm), 2011Co-Authors: Rui Huang, Ufuk Topcu, K. Mani Chandy, Christopher R. ClarkeAbstract:Hybrid energy systems with renewable generation are built in many remote areas where the renewable resources are abundant and the environment is clean. We present a case study of the Catalina Island in California for which a system with photovoltaic (PV) arrays, wind turbines, and battery storage is designed based on empirical weather and load data. To determine the system size, we formulate an optimization problem that minimizes the total construction and operation cost subject to Maximum Tolerable Risk. Simulations using the Hybrid Optimization Model for Electric Renewable (HOMER) is used to determine the feasible set of the optimization problem.
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Optimal design of hybrid energy system with PV/wind turbine/storage: A case study
2011 IEEE International Conference on Smart Grid Communications (SmartGridComm), 2011Co-Authors: Rui Huang, Ufuk Topcu, Mani K. Chandy, Christopher R. ClarkeAbstract:Hybrid energy systems with renewable generation are built in many remote areas where the renewable resources are abundant and the environment is clean. We present a case study of the Catalina Island in California for which a system with photovoltaic (PV) arrays, wind turbines, and battery storage is designed based on empirical weather and load data. To determine the system size, we formulate an optimization problem that minimizes the total construction and operation cost subject to Maximum Tolerable Risk. Simulations using the Hybrid Optimization Model for Electric Renewable (HOMER) is used to determine the feasible set of the optimization problem.
Lützen Portengen - One of the best experts on this subject based on the ideXlab platform.
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On the approach for calculating occupational exposure limits for diesel motor exhaust: authors’ response
Occupational and Environmental Medicine, 2017Co-Authors: Roel Vermeulen, Lützen PortengenAbstract:We thank Dr Mohner for his letter to the editor on our recent report on the acceptable Risk (AR) and Maximum Tolerable Risk (MTR) of dying from lung cancer due to diesel motor exhaust (DME). Our calculations, which included alternative Risk estimates based on reanalyses by us and others, indicated that an acceptable excess Risk of lung cancer mortality can only be achieved at very low DME exposure levels. This suggests that diesel engines using older technologies should be removed from the workplace when possible or emissions strictly controlled. Dr Mohner argues in his letter that the derived exposure limits were too conservative. The first argument is based on a recent review by Dr Mohner and Wendt in Critical Reviews in Toxicology where they conclude that there are methodological issues with the three studies …
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Is diesel equipment in the workplace safe or not
Occupational and Environmental Medicine, 2016Co-Authors: Roel Vermeulen, Lützen PortengenAbstract:Objectives Recently, diesel motor exhaust (DME) has been classified as a known human carcinogen. We used data from epidemiological studies of diesel exposures to perform a quantitative Risk assessment to calculate DME exposure levels, expressed as elemental carbon (EC), corresponding to acceptable Risk (AR) and Maximum Tolerable Risk (MTR) levels of 4 to 10 −5 and 4 to 10 −3 for the lifetime excess probability of dying from lung cancer. Methods Previously published slope estimates (n=14) of the exposure–response curve (ERC) for EC exposure and lung cancer were used in life-table analyses to calculate EC exposure levels corresponding to the specified AR and MTR levels. Results Considered ERC slope factors ranged from 0.00060 to 0.0012 natural logarithm of the relative rate (InRR) per μg/m 3 years based on different selections of studies and study-specific Risk estimates. Exposure limits based on these slope factors were between 0.009–0.017 and 0.85–1.67 μg/m 3 EC for the AR and MTR, respectively. Conclusions Derived exposure limits based on the AR and MTR are around or well below 1 μg/m 3 EC. Such limits are below current occupational exposure levels, and in some instances even below environmental exposure levels. Although uncertainties exist in the exact slope factors, these results indicate that an acceptable excess lung cancer mortality Risk can only be achieved at very low DME exposure levels, suggesting that diesel engines using older technologies should be removed from the workplace when possible or emissions strictly controlled.
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Leukemia from Dermal Exposure to Cyclophosphamide among Nurses in the Netherlands: Quantitative Assessment of the Risk
Annals of Occupational Hygiene, 2014Co-Authors: Wouter Fransman, Lützen Portengen, Hans Kager, Tim Meijster, Dick Heederik, Hans Kromhout, Bas J. BlaauboerAbstract:Several studies showed that oncology nurses are exposed to antineoplastic drugs via the skin during daily activities. Several antineoplastic drugs (including cyclophosphamide) have been classified as carcinogenic to humans. This study aims to assess the leukemia Risk of occupational exposure to cyclophosphamide. Average task frequencies from the population of oncology nurses in the Netherlands and task-based dermal exposure intensities were used to calculate oncology nurses’ dermal exposure levels. A dermal absorption model in combination with a physiologically based pharmacokinetic model was used to assess the delivered dose of cyclophosphamide and its active metabolites in the bone marrow. This delivered dose was subsequently related to pharmacodynamic and epidemiological information from a longitudinal study with cyclophosphamide-treated patients to estimate the excess lifetime leukemia Risk at age 80 for Dutch oncology nurses after 40 years of exposure to cyclophosphamide. The excess lifetime leukemia Risk at age 80 of an exposed oncology nurse after 40 years of dermal exposure to cyclophosphamide was estimated to be 1.04 per million oncology nurses. This Risk could potentially increase to a Maximum of 154 per million if a nurse performs all cyclophosphamide-related tasks with the Maximum frequency (as observed in this population) and is exposed to Maximum exposure intensities for each task without using protective gloves for 40 years. This study indicates that the Risk of an oncology nurse in a Dutch hospital with an average dermal exposure to cyclophosphamide is well below the Maximum Tolerable Risk of one extra death from cancer per 250 deaths after 40 years of occupational exposure, and that this level is not exceeded in a worst-case scenario.
Rui Huang - One of the best experts on this subject based on the ideXlab platform.
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SmartGridComm - Optimal design of hybrid energy system with PV/wind turbine/storage: A case study
2011 IEEE International Conference on Smart Grid Communications (SmartGridComm), 2011Co-Authors: Rui Huang, Ufuk Topcu, K. Mani Chandy, Christopher R. ClarkeAbstract:Hybrid energy systems with renewable generation are built in many remote areas where the renewable resources are abundant and the environment is clean. We present a case study of the Catalina Island in California for which a system with photovoltaic (PV) arrays, wind turbines, and battery storage is designed based on empirical weather and load data. To determine the system size, we formulate an optimization problem that minimizes the total construction and operation cost subject to Maximum Tolerable Risk. Simulations using the Hybrid Optimization Model for Electric Renewable (HOMER) is used to determine the feasible set of the optimization problem.
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Optimal design of hybrid energy system with PV/wind turbine/storage: A case study
2011 IEEE International Conference on Smart Grid Communications (SmartGridComm), 2011Co-Authors: Rui Huang, Ufuk Topcu, Mani K. Chandy, Christopher R. ClarkeAbstract:Hybrid energy systems with renewable generation are built in many remote areas where the renewable resources are abundant and the environment is clean. We present a case study of the Catalina Island in California for which a system with photovoltaic (PV) arrays, wind turbines, and battery storage is designed based on empirical weather and load data. To determine the system size, we formulate an optimization problem that minimizes the total construction and operation cost subject to Maximum Tolerable Risk. Simulations using the Hybrid Optimization Model for Electric Renewable (HOMER) is used to determine the feasible set of the optimization problem.
De Snoo Gr - One of the best experts on this subject based on the ideXlab platform.
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Linking land use with pesticides in Dutch surface waters.
Communications in agricultural and applied biological sciences, 2020Co-Authors: Van't Zm, Martina G. Vijver, Wil L. M. Tamis, De Snoo GrAbstract:Compared with other European countries The Netherlands has a relatively high level of pesticide consumption, particularly in agriculture. Many of the compounds concerned end up in surface waters. Surface water quality is routinely monitored and numerous pesticides are found to be present in high concentrations, with various standards being regularly exceeded. Many standards-breaching pesticides exhibit regional patterns that can be traced back to land use. These patterns have been statistically analysed by correlating surface area per land use category with standards exceedance per pesticide, thereby identifying numerous significant correlations with respect to breaches of both the ecotoxicological standard (Maximum Tolerable Risk, MTR) and the drinking water standard. In the case of the MTR, greenhouse horticulture, floriculture and bulb-growing have the highest number as well as percentage of standard-breaching pesticides, despite these market segments being relatively small in terms of area cropped. Cereals, onions, vegetables, perennial border plants and pulses are also associated with many pesticides that exceed the drinking water standard. When a correction is made for cropped acreage, cereals and potatoes also prove to be a major contributor to monitoring sites where the MTR standard is exceeded. Over the period 1998-2006 the land-use categories with the most and highest percentage of standards-exceeding pesticides (greenhouse horticulture, bulb-growing and flower cultivation) showed an increase in the percentage of standards-exceeding compounds.
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Atlas of pesticide concentrations in Dutch surface waters: a pilot study.
Communications in agricultural and applied biological sciences, 2020Co-Authors: Van 't Zelfde, De Snoo GrAbstract:A pilot study was conducted to explore the potential for geographically mapping concentrations of individual pesticides in Dutch surface waters and compiling these maps into a National Pesticide Atlas. This atlas could be used for various purposes: 1) To see where specific pesticides are monitored, observed and find out whether these are problematical. 2) To explore the relationship between environmental pesticide levels and land use, using the results as feedback to improve national pesticide admission procedures (post-registration review) 3) To review the quality of the present Dutch pesticide monitoring system. For the study we used measured data for the years 1997 and 1998, preparing maps for six illustrative pesticides. The data are presented on a grid scale of 5x5 km. Pesticide concentrations are compared with three standards: the EU drinking water standard , the Maximum Tolerable Risk (MTR) level and the admission standard set by the Dutch Pesticide Admission Board (CTB). The results show that all these pesticides can be satisfactorily mapped at the national level and that for most of the compounds investigated a useful relationship can be established between environmental concentration and land use. The maps also serve to show up gaps in the present pesticide monitoring system. The study yielded several new insights, among them that standards were found to be exceeded in areas and at times of the year not anticipated on the basis of land use and pesticide use statistics. As a follow-up to this pilot study a new project has been started to develop an internet version of the pesticide atlas for all measured pesticides in The Netherlands.