Redundant Equipment Research Articles

Evaluation on Input-output Efficiency of Land Consolidation Project Based on DEA --- A Case Study of Land Consolidation Project in Chongyang County, Hubei Province

This article studies four land consolidation projects in four towns of Chongyang County, Hubei Province, establishes system indexes for evaluation on input and output of land consolidation projects in all the four towns and employs DEA method to make an analysis of the relative efficiency of the projects in order to make an analysis of the actual efficiency of land consolidation, decide whether land consolidation is highly effective and point out a direction of improvement for higher land consolidation efficiency in the future. The result shows that the land consolidation in Qingshan Town and Lukou Town is ineffective and the land consolidation in Shaping Town and Baini Town is effective, with an average efficiency of 0.77. It proves that the overall efficiency of land consolidation in the four towns is at an upper-and-middle stream. Inefficiency is mainly manifested in cost of construction of a project, original equipment cost, other costs and redundancy of unpredictable costs, while increment of land use ratio, quantity of employment added per unit investment, rate of coverage of newly added green vegetation, newly added annual pure economic interests and yield rate of static investment have too low output. In order to enhance the efficiency of land consolidation, it is necessary to arrange all sorts of input in a reasonable way and pay enough attention to the output.

RAMI Analysis for Designing and Optimizing ITER Tokamak Cooling Water System

U.S. ITER is responsible for the design, engineering, and procurement of the Tokamak Cooling Water System (TCWS). TCWS is designed to provide cooling and baking for client systems that include the first wall/blanket, vacuum vessel, divertor, and neutral beam injector. Additional operations that support these primary functions include chemical control of water provided to client systems, draining and drying for maintenance, and leak detection/localization. TCWS interfaces with 27 systems including the secondary cooling system, which rejects this heat to the environment.TCWS is complex because it serves vital functions for four primary clients whose performance is critical to ITER’s success, and it interfaces with more than 20 additional ITER systems. Conceptual design of this one-of-a-kind cooling system has been completed; however, several issues remain that must be resolved before moving to the next stage of the design process. The 2004 baseline design indicated cooling loops that have no fault tolerance for component failures. During plasma operation each cooling loop relies on a single pump, a single pressurizer, and one heat exchanger. Consequently, failure of any of these would render TCWS inoperable, resulting in plasma shutdown. The application of reliability, availability, maintainability, and inspectability (RAMI) tools during the different stages of TCWS design is crucial for optimization purposes and for maintaining compliance with project requirements.RAMI analysis indicates appropriate equipment redundancy that provides graceful degradation in the event of an equipment failure. Results from the study indicate that pump and heat exchanger reliability are key issues.The ITER International Organization (ITER IO) RAMI group has proposed standardization for the pumps and heat exchangers to reduce fabrication risks of one-of-akind components. An aggressive maintenance/repair program should be an integral part of ITER operations. Preventive maintenance should be part of the maintenance system.For equipment that is infrequently operated, it is suggested that the key components be tested on a regular basis. The analysis has indicated that the RAMI requirements have been exceeded at this point, allowing concentration on cost optimization.

Establish a Transparent Chain-of-Custody to Mitigate Risk and Ensure Quality of Specialized Samples.

Pharmaceutical research and development has entered a new era, shifting from the one-size-fits-all approach of traditional medicine to patient-specific therapeutics. This change in treatment methodologies has placed an increased emphasis on well-preserved, well-documented biospecimens. Due to these advancements in medicine, specimen handling processes need to be in accordance with current Good Practice (GXP) quality guidelines and regulations, including Good Manufacturing Practices (GMPs), Good Laboratory Practices (GLPs), and Good Clinical Practices (GCPs), to ensure the safety of valuable biospecimen samples and their associated data. GXP guidelines delineate most aspects of clinical research. This is especially true for chain-of-custody documentation, as it provides a traceable record that guarantees unbroken control over a document, raw data, or a sample and its containers from initial collection to final disposition. Although establishing chain-of-custody can be a demanding practice, the process of verifying who has possession of specimens can be streamlined if an organization outlines chain-of-custody guidelines in their Standard Operating Procedures (SOPs). These processes and procedures ensure uniform application of best practices and successful knowledge transfer. As such, this article will outline the necessary components of establishing a highly visible and compliant chain-of-custody, including: maintaining 21 CFR Part 11 compliance; installing validated, redundant equipment for specimen storage and transportation; employing temperature-monitoring and -tracking devices; and best practices for implementing inventory and data management systems as well as audit trails.

Keeping it simple

So what is green IT? Is it recycling redundant equipment responsibly? Is it switching equipment off at the plug to make huge energy savings? It's all of that, but much more. Michelle Hazelton explains why you don't need to be an expert to start making a difference.

Reliability of operation and failure management of membrane wastewater treatment

The analysis of the long-term performance of a full-scale submerged bioreactor confirms the reliability of operation and the process sustainability in terms of environmental and health protection. The failure mode analysis was used as a problem prevention tool that enabled to identify weak areas of the treatment process and develop actions to prevent their occurrence. The major risk is undoubtly membrane damage or fouling. In full-scale operation, two types of equipment are likely to be the major cause for decrease of membrane permeability – faulty pre-treatment, mainly fine screening and grease removal, and poor activated sludge properties induced by faulty aeration or shock salt and toxic loadings. PLC and SCADA systems are very important and reliable tools for MBR operation, but can be disturbed by some minor malfunctions or unreliable equipment such as communication links. Redundant equipment and adequate SCADA system lead to significant reduction of risk of failure of electromechanical apparatus enabling immediate detection of any breakdown or malfunction.

SU‐GG‐T‐258: A Fast and Simple Method for Improving Accuracy of Helmet Output Factor Measurements for Gamma Knife Perfexion Unit

Purpose: To develop an efficient and an accurate method for measuring the helmet output factors for the new Gamma Knife Perfexion. The method aims to minimize the uncertainties caused by redundant equipment setup and the inter‐dosimeter variations associated with the conventional method. Method and Materials: The measurement was performed using a 16‐cm spherical phantom with the radiochromic film inserts. For each output factor measurement, we exposed a single film with two shots (e.g. either a pair of 16‐mm/8‐mm or a pair of 16‐mm/4‐mm shots) symmetrically placed along the x‐axis with respect to the central sagittal plane. The time of the exposure for each pair of shots was adjusted to deliver nearly equal amount of dose at the center of each shot. As a result, no calibration curve needed for the film analysis and the output factor was obtained directly from the ratio of the optical density readings for each pair of the shots. Results: The average values for the 8‐mm and 4‐mm helmet output factors were measured to be 0.928±0.009 and 0.817± 0.012, respectively. These values were in excellent agreement (<1.5%) with the manufacturer default values of 0.924 and 0.805 for the 8‐mm and the 4‐mm helmet respectively. In particular, the agreement with the 4‐mm helmet was the best reported in the literature showing the accuracy and the robustness of the method over the conventional measurement method. Conclusion: A simple and accurate technique for the helmet output factor measurements was demonstrated for Gamma Knife Perfexion unit. Excellent agreement was found between the measured values and the manufacturer default values. Given the simplicity of our method, we recommend validation of the output factors as part of initial commissioning or routine quality assurance checks for the new Gamma Knife Perfexion.

Management of air quality monitoring using principal component and cluster analysis—Part II: CO, NO 2 and O 3

The aim of this study was to evaluate the performance of two statistical methods, principal component analysis (PCA) and cluster analysis (CA), for the management of air quality monitoring network (AQMN) of Oporto Metropolitan Area (Oporto-MA). The specific objectives were: (i) to identify city areas with similar air pollution behaviours; and (ii) to locate emission sources. The statistical methods were applied to the mass concentrations of carbon monoxide (CO), nitrogen dioxide (NO 2) and ozone (O 3), collected in the AQMN of Oporto-MA from January 2003 to December 2005. It was demonstrated that for each pollutant the monitoring sites are grouped into different classes based on their air pollution behaviour. The sites were divided: (i) into three different groups for CO and for NO 2 and (ii) into two groups for O 3. It was also found that several monitoring sites covered city areas characterized by the same specific air pollution behaviour, suggesting then an ineffective management of the air quality-monitoring system. The redundant equipment should be transferred to other monitoring sites allowing enlargement of the monitored area. The conclusions obtained with the statistical methods were supported by the location of main emission sources through the analysis of the wind direction. Four main emission sources of CO and NO 2 were located. Additionally, it was concluded that the sea wind had an important contribution towards the increase in the O 3 concentration. For all pollutants, two sites were always coupled in one group due to the different air pollution behaviour presented in the analysed period.

Management of air quality monitoring using principal component and cluster analysis—Part I: SO 2 and PM 10

The number of sites that constitute the air quality monitoring network (AQMN) of Oporto Metropolitan Area (Oporto-MA) should be optimised, aiming to reduce significant associated expenses. Ideally, only one monitoring site should operate in an area characterized by specific air pollution behaviour. The global aim of this study was to evaluate the performance of statistical methods for the more efficient management of AQMNs. The specific objectives were: (i) to identify city areas with similar air pollution behaviours; and (ii) to locate emission sources. Two statistical techniques, principal components analysis (PCA) and cluster analysis (CA), were applied to the mass concentrations of sulphur dioxide (SO 2) and particulate matter with an aerodynamic diameter less than 10 μm (PM 10), collected in the AQMN of Oporto-MA from January 2003 to December 2005. Main results showed that the 10 monitoring sites of the AQMN could be coupled in six and no more than two groups for SO 2 and PM 10, respectively. It was found also that several monitoring sites covered city areas characterized by the same specific air pollution behaviour; suggesting then an ineffective management of the air quality monitoring system. The redundant equipment should be transferred to other monitoring sites allowing the enlargement of the monitored area. Only one main emission source of SO 2 was located and the six groups needed to characterize SO 2 mass concentrations were justified by the geographical location of that main emission source and by the variability of wind direction. Three main emission sources of PM 10 were located: (i) one inside the region defined by the AQMN, which significantly affected only two monitoring sites; and (ii) two outside that region, which affected all monitoring sites. One emission source located outside of the region affected significantly only one monitoring site in a short period of the day. Additionally this emission source decreased its impact in 2005. These findings indicate that only two monitoring sites are needed to characterize the observed PM 10 mass concentrations.

UV disinfection system downtime: Effects and mitigation

Off‐specification operation and downtime are important considerations in designing system reliability in ultraviolet (UV) light disinfection systems. This research analyzed the residual risk of Cryptosporidium infection from surface water supplies—after implementation of UV disinfection—and the corresponding UV disinfection system reliability requirements. The author concluded that achieving a maximum downtime of 0.01% (4.4 min/month) is unrealistic, even with standby power and an uninterruptible power supply. Furthermore, starting from 0.01% downtime, seemingly minor increases in downtime significantly reduce the net disinfection credit and result in diminishing returns, regardless of the validated UV disinfection system credit. Providing redundant equipment, standby power, active series compensators, and uninterruptible power supplies can increase UV disinfection system reliability. Judicious application of these and other mitigation measures will help maximize the effectiveness of UV disinfection for regulatory compliance.

On the effect of downtime costs and budget constraint on preventive and replacement policies

This work proposes a general approach to study and improve the effectiveness of the system with respect to its expected life-cycle cost rate. The model we propose considers a production system which is protected against demand fluctuations and failure occurrences with elements like stock piles, line and equipment redundancy, and the use of alternative production methods. These design policies allow to keep or minimize the effect on the nominal throughput, while corrective measures are taken. The system is also subject to an aging process which depends on the frequency and quality of preventive actions. Making decisions is difficult because of discontinuities in intervention and downtime costs and the limited budget. We present a non-linear mixed integer formulation that minimizes the expected overall cost rate with respect to repair, overhaul and replacement times and the overhaul improvement factor proposed in the literature. The model is deterministic and considers minimal repairs and imperfect overhauls. We illustrate its application with a case based on a known benchmark example.

Optimal design of work-in-process buffers

When customers demand for very short lead-times and for a strict respect of the delivery schedules, it becomes difficult to avoid the existence of relatively large work-in-process buffers. As the buffers will also increase dramatically the production costs, their design (location and capacity) should be carefully analyzed and optimized, a task that becomes rather complex for large production systems. This paper firstly introduces a series of fundamental concepts related to the reliability of production systems. Then, the rationale of an analysis method oriented to this class of systems will be presented, together with its two main components, the modelling framework and the evaluation algorithm. The method allows analysing several issues of the design and operation of the production systems, namely the redundancy of equipment, the layout of the cells and the maintenance policies. To illustrate its practical usefulness and enlighten the kind of results that the method can provide, a numerical example concerning the design of work-in-process buffers of a just-in-time manufacturing system will be presented in the final part of the paper.

Healthcare waste management: a case study from the National Health Service in Cornwall, United Kingdom

This paper looks at steps taken towards the development of a 10-year strategy for the management of healthcare waste from the National Health Service (NHS) in Cornwall, United Kingdom. The major issues and challenges that affect the management of waste by the NHS, including its organisational structure and collection infrastructure, are outlined. The waste flows of the main acute medical site are detailed, using waste audits of domestic and clinical bags, redundant equipment, bulky waste, and special waste. Some of the common barriers to change, such as staff habits and public perceptions, are also identified. Recommendations are made with respect to improvements in the overall organisational infrastructure and increased localised control. The recommendations also centre around the formation of strategic partnerships, within the site, between sites and at the broader level between the NHS and its surrounding community. An important challenge to be overcome is the need to progress from the concept of ‘waste management’, to one of sustainable decision making regarding resource use, including methods of waste minimisation at the source and recycling. Staff training and awareness underpin several of the short and medium/long term solutions suggested to reduce the waste at the source and recover value from that produced. These measures could potentially reduce disposal quantities by as much as 20–30% (wt.) and costs by around 25–35%.

Determining Rational Redundancy of 500-kV Reactors in Transmission Systems Using a Probability-Based Economic Analysis Approach: BCTC's Practice

This paper presents a methodology to determine a rational redundancy level of power system equipment based on a coordination among the electric energy market information, the total transfer capability (TTC) in the transmission system and the estimation of random equipment failures. The proposed approach includes the models of unavailability due to both repairable and aging failures of equipment, the calculation method of two discrete statistical distributions representing energy prices and export powers, and a probabilistic benefit/cost analysis technique. An actual example of 500-kV reactors at British Columbia Transmission Corporation (BCTC) has been given to demonstrate the procedure of the application. The results indicate that the redundancy level determined using this approach not only enables the utility to avoid possible losses in the income from energy sales and improves the profile of system TTC but also guarantees a high benefit/cost ratio in a financial justification of redundant equipment addition.

Elements of resilience after the World Trade Center disaster: reconstituting New York City's Emergency Operations Centre.

In this paper we examine the reconstitution of the Emergency Operations Centre (EOC) after its destruction in the World Trade Center attack, using that event to highlight several features of resilience. The paper summarises basic EOC functions, and then presents conceptions of resilience as understood from several disciplinary perspectives, noting that work in these fields has sought to understand how a natural or social system that experiences disturbance sustains its functional processes. We observe that, although the physical EOC facility was destroyed, the organisation that had been established to manage crises in New York City continued, enabling a response that drew on the resources of New York City and neighbouring communities, states and the federal government. Availability of resources--which substituted for redundancy of personnel, equipment and space--pre-existing relationships that eased communication challenges as the emergency developed and the continuation of organisational patterns of response integration and role assignments were among the factors that contributed to resilience following the attack.

ATAD, THE NEXT GENERATION: DESIGN, CONSTRUCTION, START-UP AND OPERATION OF THE FIRST MUNICIPAL 2ND GENERATION ATAD

Autothermal thermophilic aerobic digestion (ATAD) is an effective method to produce a pasteurized (Class A) biosolid. The process has not been well received in the United States because of problems with odors, poor volatile solids reduction, high dewatering costs and inflexible designs. An improved, 2 nd generation ATAD design was developed to provide high total solids reduction in a small reactor for industrial biosolids. The improved design has solved the operating and aesthetic problems inherent in the first generation of ATAD. The new unit operates automatically, reduces the total solids by nearly 50%, dewaters well at a reasonable polymer dose with no metal salt addition required and produces no odors other than ammonia. The original plan for solids handling was a dryer, which was quite expensive. Use of the 2 nd generation ATAD allowed the use of a much less expensive dryer, which reduced capital and operating expenses. The use of a dual A process also eliminated costly redundant equipment.

Reaction Crystallization of CaCO3 in a Gas-Liquid Multistage Column Crystallizer.

A multistage column crystallizer is a column crystallizer partitioned with perforated plates. From the viewpoint of economy, multistage column crystallizers have been developed to overcome the redundancy of equipment due to the duplication of mixers and other hardware in a cascade of mixed-suspension, mixed-product-removal crystallizers. The aims of this study are to clarify the characteristics of the multistage column crystallizers and to control the calcium carbonate particle size. The staging effects of the column crystallizer on the particle size were experimentally investigated by the gas-liquid reaction crystallization of calcium carbonate in the three-stage column crystallizer. The particle size of calcium carbonate obtained by the multistage column crystallizer becomes larger than that obtained by the standard column crystallizer. The dominant particle size increases with a decreasing opening ratio of the perforated plate, whereas it decreases with increasing CO2 content in the gas, because the particles produced re-dissolve by the dissolution of CO2.

Integrating Microbiology into the Drigg Post-Closure Radiological Safety Assessment

ABSTRACTBNFL owns and operates the UK's principal solid Low Level Radioactive Waste disposal site at Drigg in Cumbria, north west England. Drigg has been receiving waste since 1959 with approximately 900,000 m3of waste disposed of to date. Waste accepted for disposal at Drigg comes in a variety of forms including rubble, spoil, redundant equipment, scrap and process waste, and typically contains significant metallic and cellulosic components. The organic content of the waste means that microbial activity plays a significant role in the development of the repository environment. Consequently, microbial processes are integrated into many aspects of the Drigg Post-Closure Radiological Safety Assessment (PCRSA). This begins with the identification and screening of relevant features, events and processes, through supporting research, engineering designs and finally integration into radiological safety assessment modelling. This paper outlines how and where microbiology is integrated into the Drigg PCRSA and indicates areas of active research.

Sprint long distance network survivability: today and tomorrow

The high reliability exhibited by the Sprint long distance network is the result of many interrelated factors. The network utilizes robust architectures, systems, and equipment to provide a reliable transport infrastructure. Redundant equipment, conservative synchronization, protected power, and other factors combine to form a dependable foundation. New architectures and systems are under development to meet the changing demands of customers. This article summarizes Sprint's current network reliability, and emerging demands and technology, and presents possible directions for the future Sprint network. Sprint selected the SONET four-fiber bidirectional line switched ring (4F BLSR) architecture for the vast majority of its transport network architecture. A 4F BLSR architecture requires four fibers, or four optical wavelengths of wave division multiplexing (WDM), to accommodate a work and protect path in each direction around a ring of network elements or add-drop multiplexers (ADMs).

Probabilistic fire analysis capabilities, applications and weak points

Fires occur in nuclear power plants with a relatively high frequency, and can cause multiple and simultaneous failures of redundant or diverse plant equipment or systems. The development of a method of probabilistic fire risk analysis, although subject to more uncertainties than internal events, can provide insights complementary to those provided by deterministic analysis. In many cases, it can also provide a more realistic point of view of the risk involved.

Optimal Short-Term Scheduling of Maintenance and Production for Multipurpose Plants

The increased emphasis on the production of low-volume, high-value-added products has resulted in a renewed interest in multipurpose batch plants, which tend to be the most economical facilities for the production of small amounts of many different products. In such plants, the competition between the different products for the shared production resources gives rise to complex production scheduling problems. Amongst other factors, the profitability of a plant also depends on its availability which directly depends on the maintenance work carried out. In multipurpose plants, the integrated planning of production and maintenance so that these problems are solved simultaneously should result in increased profitability compared to the case where they are solved in isolation. This may be due, for example, to the ability to exploit equipment idle time or redundancy to perform preventive maintenance while having a minimal effect on production. We describe a mathematical model for simultaneously scheduling production and maintenance activities within a multipurpose plant, taking account of both production resources (e.g. equipment items) and maintenance resources (e.g., crews)