Autotransplantation of cryopreserved ovarian tissue in 12 women with chemotherapy-induced premature ovarian failure: the Danish experience

DEFF Research Database (Denmark)

Schmidt, Kirsten Tryde; Rosendahl, Mikkel; Ernst, Erik

2011-01-01

To describe a cohort of 12 Danish women who received autotransplantation of frozen-thawed cryopreserved ovarian tissue because of premature ovarian failure after cancer treatment.......To describe a cohort of 12 Danish women who received autotransplantation of frozen-thawed cryopreserved ovarian tissue because of premature ovarian failure after cancer treatment....

Premature ovarian failure

Directory of Open Access Journals (Sweden)

Vujović Svetlana

2012-01-01

Full Text Available Premature ovarian failure (POF is the occurrence of hypergonadotropic hypoestrogenic amenorrhea in women under the age of forty years. It is idiopathic in 74-90% patients. Known cases can be divided into primary and secondary POF. In primary POF genetic aberrations can involve the X chromosome (monosomy, trisomy, translocations, deletions or autosomes. Genetic mechanisms include reduced gene dosage and non-specific chromosome effects impairing meiosis, decreasing the pool of primordial follicles and increasing atresia due to apoptosis or failure of follicle maturation. Autoimmune ovarian damage is caused by alteration of T-cell subsets and T-cell mediated injury, increase of autoantibody producing B-cells, a low number of effector/cytotoxic lymphocyte, which decreases the number and activity of natural killer cells. Bilateral oophorectomy, chemotherapy, radiotherapy and infections cause the secondary POF. Symptoms of POF include irritability, nervousness, loss of libido, depression, lack of concentration, hot flushes, weight gaining, dry skin, vaginal dryness, frequent infections etc. The diagnosis is confirmed by the level of FSH of over 40 IU/L and estradiol below 50 pmol/L in women aged below 40 years. Biochemical and other hormonal analysis (free thyroxin, TSH, prolactin, testosterone, karyotype (<30 years of age, ultrasound of the breasts and pelvis are advisable. Optimal therapy is combined estrogen progestagen therapy given in a sequential rhythm, after excluding absolute contraindications. Testosterone can be added to adnexectomized women and those with a low libido. Sequential estrogen progestagen replacement therapy is the first line therapy for ovulation induction in those looking for pregnancy and after that oocyte donation will be advised. Appropriate estro-progestagen therapy improves the quality of life and prevents complications such as cardiovascular diseases, osteoporosis, stroke etc.

Outage preparation milestones - A tool to improve planned outage performance

International Nuclear Information System (INIS)

Laplatney, Jere; Hwang, Euiyoub

2006-01-01

Sustainable development of Nuclear Energy depends heavily on excellent performance of the existing fleet which in turn depend heavily on the performance of planned outages. Nuclear Power Plants who have successfully undertaken outage optimization projects have demonstrated than an effective Outage Preparation Milestone program is a key component of their improvement programs. This paper will provide background into the field of 'Outage Optimization' including the philosophy, general approach, and results obtained in the U. S. industry. The significant safety improvements afforded by properly implementing outage improvement programs will be explained. Some specific examples of outage improvements will be given including the adoption of a strong Outage Preparation Milestone Program. The paper will then describe the attributes of an effective Outage Preparation Milestone Program and list a set of specific key milestones. The key milestones are defined and the reasons for each are explained. Suggested due dates for each key milestone relative to the outage start date are provided. Successful implementation of an Outage Preparation Milestone program depends heavily upon the management tools and methods used to assure that the organization meets the milestones on time and in a quality fashion. These include methods to handle cases where milestones are not met - either partially or fully. KHNP is investigating implementing an improved Outage Preparation Milestone program for its fleet of reactors as part of its overall program to improve its performance of planned outages

Power Outages

Science.gov (United States)

... Publications Emergency Alerts Preparedness Portal Preparedness Messaging Calendar Social Media Preparedness Toolkits Preparedness News Languages About Us Build a Kit Close Search Enter Search Term(s): Main Content Home Be Informed Power Outages Power Outages Extended power outages may impact ...

[Genetic aspects of premature ovarian failure].

Science.gov (United States)

Warenik-Szymankiewicz, Alina; Słopień, Radosław

2005-01-01

Among the causes of premature ovarian failure (POF) two groups of factors are reported: factors which lead to decrease of follicular number and factors which stimulate follicular atresia. In the first group genetic factors are the most important whereas in the second: enzymatic autoimmunological, iatrogenic, toxins and infections are reported. In 1986 familiar POF on the background of long arm of chromosome X deletion was reported. Other chromosomes which are important for normal ovarian function are: chromosome 21 (AIRE gene), chromosome 11 (gene of beta FSH, ATM gene), chromosome 3 (gene responsible for BEPS syndrome) and chromosome 2 (genes of FSH and LH receptors). In this review the role of these genes and results of several epidemiological studies are reported.

Melatonin and Fertoprotective Adjuvants: Prevention against Premature Ovarian Failure during Chemotherapy.

Science.gov (United States)

Jang, Hoon; Hong, Kwonho; Choi, Youngsok

2017-06-07

Premature ovarian failure is one of the side effects of chemotherapy in pre-menopausal cancer patients. Preservation of fertility has become increasingly important in improving the quality of life of completely recovered cancer patients. Among the possible strategies for preserving fertility such as ovarian tissue cryopreservation, co-treatment with a pharmacological adjuvant is highly effective and poses less of a burden on the human body. Melatonin is generally produced in various tissues and acts as a universally acting antioxidant in cells. Melatonin is now more widely used in various biological processes including treating insomnia and an adjuvant during chemotherapy. In this review, we summarize the information indicating that melatonin may be useful for reducing and preventing premature ovarian failure in chemotherapy-treated female patients. We also mention that many adjuvants other than melatonin are developed and used to inhibit chemotherapy-induced infertility. This information will give us novel insights on the clinical use of melatonin and other agents as fertoprotective adjuvants for female cancer patients.

Evaluation of mean time between forced outage for reactor protection system using RBD and failure rate

International Nuclear Information System (INIS)

Lee, D. Y.; Park, J. H.; Hwang, I. K.; Cha, K. H.; Choi, J. K.; Lee, K. Y.; Park, J. K.

2001-01-01

The design life of nuclear power plants (NPPs) under recent construction is about fifty to sixty years. However, the duration that equipments of control systems operate without failures is at most five to ten years. Design for diversity and adequate maintenance strategy are required for NPP protection system in order to use the control equipment which has shorter life time than the design life of NPP. Fault Tree Analysis (FTA) technique, which has been applied to Probabilistics Safety Analysis (PSA), has been introduced to quantitatively evaluate the reliability of NPP I and C systems. The FTA, however, cannot properly consider the effect of maintenance. In this work, we have reviewed quantitative reliability evaluation techniques using the reliability block diagram and failure rates and applied it to the evaluation of mean time between forced outage for reactor protection system

Driving for shorter outages

International Nuclear Information System (INIS)

Tritch, S.

1996-01-01

Nuclear plant outages are necessary to complete activities that cannot be completed during the operating cycle, such as steam generator inspection and testing, refueling, installing modifications, and performing maintenance tests. The time devoted to performing outages is normally the largest contributor to plant unavailability. Similarly, outage costs are a sizable portion of the total plant budget. The scope and quality of work done during outages directly affects operating reliability and the number of unplanned outages. Improved management and planning of outages enhances the margin of safety during the outage and results in increased plant reliability. The detailed planning and in-depth preparation that has become a necessity for driving shorter outage durations has also produced safer outages and improved post-outage reliability. Short outages require both plant and vendor management to focus on all aspects of the outage. Short outage durations, such as 26 days at South Texas or 29 days at North Anna, require power plant inter-department and intra-department teamwork and communication and vendor participation. In this paper shorter and safer outage at the 3-loop plants in the United States are explained. (J.P.N.)

DYSFUNCTION OF MONOCYTES AND DENDRITIC CELLS IN PATIENTS WITH PREMATURE OVARIAN FAILURE

NARCIS (Netherlands)

HOEK, A; VAN KASTEREN, Y; DE HAAN-MEULMAN, M; SCHOEMAKER, J; DREXHAGE, HA

1993-01-01

PROBLEM: Due to the presence of ovarian antibodies it has been suggested that premature ovarian failure (POF) belongs to the autoimmune endocrinopathies. Monocytes and the monocyte-derived dendritic cells play a prominent role in the initial stages of endocrine autoimmune reactions: the accumulation

The status of the Hanaro class 4 power outage

International Nuclear Information System (INIS)

Hyungkyoo, K.; Hoansung, J.; Jongsup, W.

2004-01-01

Electric power is essential for all industrial plant. All who use electric power desire a perfect frequency, voltage stability, and reliability all the time. But this cannot be realized in practice because of the many causes of a power supply disturbance that are beyond the control of the utility. Since the first criticality of the Hanaro research reactor, the major reasons for reactor trips were system malfunctions and inexperienced operators in the initial stage of its operation. As Hanaro is stabilizing, the power supply outage becomes the major reason for a reactor trip. This paper describes the status of power supply outages. This paper deals with not only the outages which have an effect on Hanaro operation but also the reasons for the Hanaro class-4 power outages. The class-4 power is a commercial power which supplies the load centers and the large motors such as primary cooling pumps and secondary cooling pumps. Even if a class-4 power outage occurs, Hanaro is safe because of the reactor cooling by natural convection and the flywheel effect of the primary cooling pumps. The analysis of the characteristics and the trends of the outages can provide clues to how the outages can be minimized and what the impact of the outages are on the operation. For the site-wide class-4 power, the latest failure rate has been 2.36 per year and the mean time to repair is 23,78 minutes for the exponentially weighted mowing average. The unavailability of the Class-4 power is 1.5 10 -4

Boiler tube failure prevention in fossil fired boilers

International Nuclear Information System (INIS)

Townsend, R.D.

1993-01-01

It is the common experience of power generating companies worldwide that the main causes of forced outages on power plant are those due to boiler tube failures on fossil units. The main reason for the large number of failures are the severe environmental conditions in fossil boilers as the effects of stress, temperature, temperature gradients, corrosion, erosion and vibration combine to produce degradation of the tube steel. Corrosion by oxidation, by combustion products and by impure boiler water can significantly reduce the tube wall thickness and result in failure of a tube many years before its designed service life. Errors can also occur in the design manufacturer, storage, operation, and maintenance of boiler tubing and the wrong material installed in a critical location can lead to premature failure. Altogether, experts in the US and UK, from many different disciplines, have identified seven broad categories of boiler tube failure mechanisms. 1 tab., 2 figs

35/30 outage improvement project

International Nuclear Information System (INIS)

Clewett, L.

2011-01-01

Outage performance is a significant contributor to the business plan at Bruce Power. A process improvement initiative commenced in 2010-11 to improve outage efficiency and predictability. 12 teams (over 200 people) participated in improvement identification in four areas: Organizational Engagement; Outage Scope; Resources; and, Critical Outage Execution. Out of over 550 initiatives identified, 200 are being incorporated into the Outage Improvement Initiative. Key deliverables include: Development of a long-range 'fleet-level' business strategy to integrate outage duration, outage improvements and unit refurbishments; Development of a 35 day outage schedule template; Determining optimal outage organization to perform outages on an 8-unit site; Improved schedule adherence and productivity; Process to integrate scope needs to support life-cycle and long-range outage needs improvement while meeting near term and regulatory requirements; Consistent methodology in planning of outages to front-end load the high risk work into the outage schedule; Consistent baseline by senior leaders for the expectations of milestone ownership and completion; Consistent framework for milestone compliance and preparation; Communication strategy to educate personnel on the importance of the outage program and nuclear safety, business goals, and budget; and, Suite of metrics based upon industry benchmarks. The Outage Improvement Initiative has a goal of 35 day outages every 30 months. This potentially represents considerable savings to the Bruce Power business plan, both direct revenue savings attributed to reduced outage duration, as well as incremental outage cost savings. Other improvements from the initiative will include personnel radiation exposure and equipment reliability due to decreased outage duration and adherence to scoping, assessing and long lead part milestones. This presentation will describe the outage improvement initiatives to achieve a goal of consistent 35 day outages

35/30 outage improvement project

Energy Technology Data Exchange (ETDEWEB)

Clewett, L. [Bruce Power, Tiverton, Ontario (Canada)

2011-07-01

Outage performance is a significant contributor to the business plan at Bruce Power. A process improvement initiative commenced in 2010-11 to improve outage efficiency and predictability. 12 teams (over 200 people) participated in improvement identification in four areas: Organizational Engagement; Outage Scope; Resources; and, Critical Outage Execution. Out of over 550 initiatives identified, 200 are being incorporated into the Outage Improvement Initiative. Key deliverables include: Development of a long-range 'fleet-level' business strategy to integrate outage duration, outage improvements and unit refurbishments; Development of a 35 day outage schedule template; Determining optimal outage organization to perform outages on an 8-unit site; Improved schedule adherence and productivity; Process to integrate scope needs to support life-cycle and long-range outage needs improvement while meeting near term and regulatory requirements; Consistent methodology in planning of outages to front-end load the high risk work into the outage schedule; Consistent baseline by senior leaders for the expectations of milestone ownership and completion; Consistent framework for milestone compliance and preparation; Communication strategy to educate personnel on the importance of the outage program and nuclear safety, business goals, and budget; and, Suite of metrics based upon industry benchmarks. The Outage Improvement Initiative has a goal of 35 day outages every 30 months. This potentially represents considerable savings to the Bruce Power business plan, both direct revenue savings attributed to reduced outage duration, as well as incremental outage cost savings. Other improvements from the initiative will include personnel radiation exposure and equipment reliability due to decreased outage duration and adherence to scoping, assessing and long lead part milestones. This presentation will describe the outage improvement initiatives to achieve a goal of consistent 35 day

On test and maintenance: Optimization of allowed outage time

International Nuclear Information System (INIS)

Mavko, B.; Cepin, M.T.

2000-01-01

Probabilistic Safety Assessment is widely becoming standard method for assessing, maintaining, assuring and improving the nuclear power plant safety. To achieve one of its many potential benefits, the optimization of allowed outage time specified in technical specifications is investigated. Proposed is the risk comparison approach for evaluation of allowed outage time. The risk of shutting the plant down due to failure of certain equipment is compared to the risk of continued plant operation with the specified equipment down. The core damage frequency serves as a risk measure. (author)

Premature ovarian failure/dysfunction following surgical treatment of polycystic ovarian syndrome: A case series

Directory of Open Access Journals (Sweden)

T.K. Al-Hussaini

2017-09-01

Full Text Available Polycystic ovarian syndrome (PCOS is one of the most common causes of infertility in women. Surgical treatment of PCOS, either by the antiquated wedge resection or ovarian drilling, is one of the commonly used lines in developing countries due to its low-cost. Premature ovarian failure and diminished ovarian reserve are serious complications of the surgical treatment but no published reports sufficiently highlighted these hazards. In this case series, we report on twenty one women aged between 19–39 years, presented to Infertility Clinic, Assiut Women Health Hospital with ovarian dysfunction, diagnosed within 6–36 months after surgical management of PCOS. Nineteen of them had laparoscopic bilateral ovarian drilling using electrocauterization, and the last two had bilateral wedge resection of the ovaries through minilaparotomy. Accurate and documented diagnosis of PCOS, appropriate surgical training, adjusted thermal injury and adjusted number of punctures are essential for the avoidance of excessive damage to the ovaries. Under treatment (failure of drilling is much better than premature ovarian failure or diminishing ovarian reserve.

Improving nuclear utility generation capacity, understanding the sources of forced outage and learning how to prevent them

International Nuclear Information System (INIS)

Brodeur, D.L.; Todreas, N.E.; Angus, V.T.

1998-01-01

MIT and PECO Energy have completed a detailed examination of the sources of forced outages at the Limerick Generating Station (LGS) Boiling Water Reactor Class IV (BWR IV) site over a five year period and contrasted that information to similar BWR IV utilities in the United States over the same period. Each forced outage was attributed to one system and assigned causal codes of equipment versus human factors and failure attributes such as weak design, poor craftsmanship, and worn parts. It was found that fifty four percent of the lost power at LGS was the result of Balance of Plant failures. Industry wide data identifies fifty nine percent of the lost power as attributed to Balance of Plant failures. Balance of Plant systems are those systems not included in the primary and safety related system category. Considering failure causal factors, forty six percent of the lost power at the utility under study was the result of equipment factors such as weak design or worn parts. Significantly, the study showed a high variance between those systems which caused significant forced outage at the two sister LGS units. This demonstrated the infrequent nature of plant forced outages within a given system. This was supported by the observation that dominant systems attributing to forced outage at LGS were not equally represented in industry data. It is suggested that for individual utilities to dramatically improve unit capability factors with regard to Balance of Plant systems, they must learn from industry wide experiences and develop cooperative means of exchanging lessons learned among similarly designed plants and systems. With the broad knowledge base of system failures, current designs must be frequently assessed and altered until each system poses an acceptable level of risk to generation capacity. (author)

Environmental determinants of unscheduled residential outages in the electrical power distribution of Phoenix, Arizona

International Nuclear Information System (INIS)

Maliszewski, Paul J.; Larson, Elisabeth K.; Perrings, Charles

2012-01-01

The sustainability of power infrastructures depends on their reliability. One test of the reliability of an infrastructure is its ability to function reliably in extreme environmental conditions. Effective planning for reliable electrical systems requires knowledge of unscheduled outage sources, including environmental and social factors. Despite many studies on the vulnerability of infrastructure systems, the effect of interacting environmental and infrastructural conditions on the reliability of urban residential power distribution remains an understudied problem. We model electric interruptions using outage data between the years of 2002 and 2005 across Phoenix, Arizona. Consistent with perceptions of increased exposure, overhead power lines positively correlate with unscheduled outages indicating underground cables are more resistant to failure. In the presence of overhead lines, the interaction between birds and vegetation as well as proximity to nearest desert areas and lakes are positive driving factors explaining much of the variation in unscheduled outages. Closeness to the nearest arterial road and the interaction between housing square footage and temperature are also significantly positive. A spatial error model was found to provide the best fit to the data. Resultant findings are useful for understanding and improving electrical infrastructure reliability. - Highlights: ► Unscheduled outages were related to interacting environmental and infrastructural conditions. ► Underground feeders are more resistant to failure. ► In the presence of overhead lines, birds, vegetation, and proximity to desert areas are positive driving factors. ► Proximity to arterial roads and a proxy for energy demand were significantly positive. ► Outages were most spatially dependent up to around 350 m.

Outage information system

International Nuclear Information System (INIS)

Svengren, Haakan; Meyer, Brita Diskerud

2005-09-01

Today's control room systems are designed to operate during power operation, and there is clearly a need for a system to support control room personnel in automatically supervising the status of the plant during the outage period. In order to improve the supervision of Nuclear Power Plants during outages, three prototypes of the Outage Information system have been designed by the Halden Project, one for PWR and two for BWR. The Outage Information System is presented on a large screen, centrally placed in the control room. There will be a PC connected to manage the system. By using signals from the process as input to logic diagrams reflecting the plant's Safety Technical Specifications, the system automatically is supervising that requirements in Safety Technical Specifications are fulfilled during all plant states of the outage period. The system also automatically gives an overview of the status of safety systems and electrical bus bars. Alarm will occur if a requirement in the Safety Technical Specifications is not fulfilled or if a component planned to be ready for operation, is inoperable. In addition, selected measurements being important during the outage period are presented on the large screen. Which measurements and in which way the values will be presented, depends on the plant's control room design and work practice. (Author)

Cost of Lightning Strike Related Outages of Visual Navigational Aids at Airports in the United States

Science.gov (United States)

Rakas, J.; Nikolic, M.; Bauranov, A.

2017-12-01

Lightning storms are a serious hazard that can cause damage to vital human infrastructure. In aviation, lightning strikes cause outages to air traffic control equipment and facilities that result in major disruptions in the network, causing delays and financial costs measured in the millions of dollars. Failure of critical systems, such as Visual Navigational Aids (Visual NAVAIDS), are particularly dangerous since NAVAIDS are an essential part of landing procedures. Precision instrument approach, an operation utilized during the poor visibility conditions, utilizes several of these systems, and their failure leads to holding patterns and ultimately diversions to other airports. These disruptions lead to both ground and airborne delay. Accurate prediction of these outages and their costs is a key prerequisite for successful investment planning. The air traffic management and control sector need accurate information to successfully plan maintenance and develop a more robust system under the threat of increasing lightning rates. To analyze the issue, we couple the Remote Monitoring and Logging System (RMLS) database and the Aviation System Performance Metrics (ASPM) databases to identify lightning-induced outages, and connect them with weather conditions, demand and landing runway to calculate the total delays induced by the outages, as well as the number of cancellations and diversions. The costs are then determined by calculating direct costs to aircraft operators and costs of passengers' time for delays, cancellations and diversions. The results indicate that 1) not all NAVAIDS are created equal, and 2) outside conditions matter. The cost of an outage depends on the importance of the failed system and the conditions that prevailed before, during and after the failure. The outage that occurs during high demand and poor weather conditions is more likely to result in more delays and higher costs.

Cycle 7 outage experience

International Nuclear Information System (INIS)

Gadeken, A.D.

1986-03-01

The scheduled 58-day refueling outage in preparation for the seventh operating cycle of the Fast Flux Test Facility (FFTF) was successfully completed three days ahead of schedule. The planning and execution of the outage was greatly aided by Project/2 automated scheduling capabilities. For example, the use of ''maintenance windows'' and resource loading capabilities was particularly effective. The value of the planning process was demonstrated by the smooth transition into the outage phase after an early shutdown and set the stage for our best outage to date

Distributed power-line outage detection based on wide area measurement system.

Science.gov (United States)

Zhao, Liang; Song, Wen-Zhan

2014-07-21

In modern power grids, the fast and reliable detection of power-line outages is an important functionality, which prevents cascading failures and facilitates an accurate state estimation to monitor the real-time conditions of the grids. However, most of the existing approaches for outage detection suffer from two drawbacks, namely: (i) high computational complexity; and (ii) relying on a centralized means of implementation. The high computational complexity limits the practical usage of outage detection only for the case of single-line or double-line outages. Meanwhile, the centralized means of implementation raises security and privacy issues. Considering these drawbacks, the present paper proposes a distributed framework, which carries out in-network information processing and only shares estimates on boundaries with the neighboring control areas. This novel framework relies on a convex-relaxed formulation of the line outage detection problem and leverages the alternating direction method of multipliers (ADMM) for its distributed solution. The proposed framework invokes a low computational complexity, requiring only linear and simple matrix-vector operations. We also extend this framework to incorporate the sparse property of the measurement matrix and employ the LSQRalgorithm to enable a warm start, which further accelerates the algorithm. Analysis and simulation tests validate the correctness and effectiveness of the proposed approaches.

Darlington Station outage - a maintenance perspective

International Nuclear Information System (INIS)

Plourde, J.; Marczak, J.; Stone, M.; Myers, R.; Sutton, K.

1997-01-01

Ontario Hydro's Darlington Nuclear Generating Station (4x881MW(e)net) has carried out its first station outage since full commercial operation. The outage presented challenges to the organization in terms of outage planning, support, management, and safe execution within the constraints of schedule, budget and resources. This paper will focus on the success of the outage maintenance program, identifying the major work programs - a vacuum structure and containment outage, an emergency service water system outage, an emergency coolant injection system outage, intake channel inspections, low pressure service water inspections, and significant outage maintenance work on each of the four reactor units. Planning for the outage was initiated early in anticipation of this important milestone in the station's life. Detailed safety reviews - nuclear, radiation, and conventional - were conducted in support of the planned maintenance program. System lineup and work protection were provided by the Station Operator work group. Work protection permitry was initiated well in advance of the outage. Station maintenance staff resources were bolstered in support of the outage to ensure program execution could be maintained within the schedule. Training programs were in place to ensure that expectations were clear and that high standards would be maintained. Materials management issues in support of maintenance activities were given high priority to ensure no delays to the planned work. Station management review and monitoring in preparation for and during the outage ensured that staff priorities remained focused. Lessons learned from the outage execution are being formalized in maintenance procedures and outage management procedures, and shared with the nuclear community. (author)

Outage planning in Japan

International Nuclear Information System (INIS)

Nedderman, John.

1997-01-01

Nuclear plant operators in Japan are constrained to keep refuelling and maintenance outages to a minimum by the regulation limiting operating cycles to no longer than 13 months. Outage planning by two contrasting operators is described. Hokkaido Electric, which operates only one plant, Tomari, with two PWRs, plans to reduce outage time from the present 65 days in two stages. Detailed review of previous outage schedules has shown that a reduction to 59 days should be achievable by careful planning without any fundamental changes. The second reduction to 49 days will require such measures as relaxing water purity standards, rescheduling fuel unloading and loading shifts and speeding up eddy current testing of primary equipment by using steam generator nozzle dams. Kansai Electric, operating 11 PWRs at three plants, has scope for reducing outages at all of its units using a range of measures. Steam generator replacement in the seven oldest reactors, completed in July 1997, is by far the most significant of these and is expected to save 64 days repair time in a previous average outage time of 131 days. (UK)

Benchmark Report on Key Outage Attributes: An Analysis of Outage Improvement Opportunities and Priorities

Energy Technology Data Exchange (ETDEWEB)

Germain, Shawn St. [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Farris, Ronald [Idaho National Laboratory (INL), Idaho Falls, ID (United States)

2014-09-01

Advanced Outage Control Center (AOCC), is a multi-year pilot project targeted at Nuclear Power Plant (NPP) outage improvement. The purpose of this pilot project is to improve management of NPP outages through the development of an AOCC that is specifically designed to maximize the usefulness of communication and collaboration technologies for outage coordination and problem resolution activities. This report documents the results of a benchmarking effort to evaluate the transferability of technologies demonstrated at Idaho National Laboratory and the primary pilot project partner, Palo Verde Nuclear Generating Station. The initial assumption for this pilot project was that NPPs generally do not take advantage of advanced technology to support outage management activities. Several researchers involved in this pilot project have commercial NPP experience and believed that very little technology has been applied towards outage communication and collaboration. To verify that the technology options researched and demonstrated through this pilot project would in fact have broad application for the US commercial nuclear fleet, and to look for additional outage management best practices, LWRS program researchers visited several additional nuclear facilities.

Cytogenetics of Premature Ovarian Failure: An Investigation on 269 Affected Women

Directory of Open Access Journals (Sweden)

Simona Baronchelli

2011-01-01

Full Text Available The importance of X chromosome in the aetiology of premature ovarian failure (POF is well-known but in many cases POF still remains idiopathic. Chromosome aneuploidy increase is a physiological phenomenon related to aging, but the role of low-level sex chromosome mosaicism in ovarian function is still undiscovered. Standard cytogenetic analysis was carried out in a total of 269 patients affected by POF: 27 chromosomal abnormalities were identified, including X chromosome and autosomal structural and numerical abnormalities. In 47 patients with 46,XX karyotype we performed interphase FISH using X alpha-satellite probe in order to identify X chromosome mosaicism rate. Aneuploidy rate in the patient group was significantly higher than the general population group. These findings underline the importance of X chromosome in the aetiology of POF and highlight the potential role of low-level sex chromosome mosaicism in ovarian aging that may lead to a premature onset of menopause.

Diablo Canyon refueling outage program

International Nuclear Information System (INIS)

McLane, W.B.; Irving, T.L.

1991-01-01

Management of outages has become one of the most talked about subjects in the nuclear power industry in the past several years. Many utilities do not perform refueling outages very well or in the past have had some outages that they would not like to repeat and in some cases do not even like to think about. With the growing cost of energy and the demands placed on utilities to improve capacity factors, it is very easy for management to focus on shortening refueling outage durations as a prime objective in improving overall corporate performance. So it is with Pacific Gas and Electric Company and the Diablo Canyon power plant. A review of their refueling outage performance reflects a utility that is responding to the nuclear industry's call for improved outage performance

Premature failure of dissimilar metal weld joint at intermediate temperature superheater tube

OpenAIRE

Al Hajri, Mohammed; Malik, Anees U.; Meroufel, Abdelkader; Al-Muaili, Fahd

2015-01-01

Dissimilar metal weld (DMW) joint between alloyed steel (AS) and stainless steel (SS) failed at one of intermediate temperature superheater (ITSH) tube in steam/power generation plant boiler. The premature failure was detected after a relatively short time of operation (8 years) where the crack propagated circumferentially from AS side through the ITSH tube. Apart from physical examination, microstructural studies based on optical microscopy, SEM and EDX analysis were performed. The results o...

Development of Methodologies for Technology Deployment for Advanced Outage Control Centers that Improve Outage Coordination, Problem Resolution and Outage Risk Management

Energy Technology Data Exchange (ETDEWEB)

Shawn St. Germain; Ronald Farris; Heather Medeman

2013-09-01

This research effort is a part of the Light-Water Reactor Sustainability (LWRS) Program, which is a research and development (R&D) program sponsored by Department of Energy (DOE) and performed in close collaboration with industry R&D programs that provides the technical foundations for licensing and managing the long-term, safe, and economical operation of current nuclear power plants. The LWRS program serves to help the U.S. nuclear industry adopt new technologies and engineering solutions that facilitate the continued safe operation of the plants and extension of the current operating licenses. The long term viability of existing nuclear power plants in the U.S. will depend upon maintaining high capacity factors, avoiding nuclear safety issues and reducing operating costs. The slow progress in the construction on new nuclear power plants has placed in increased importance on maintaining the output of the current fleet of nuclear power plants. Recently expanded natural gas production has placed increased economic pressure on nuclear power plants due to lower cost competition. Until recently, power uprate projects had steadily increased the total output of the U.S. nuclear fleet. Errors made during power plant upgrade projects have now removed three nuclear power plants from the U.S. fleet and economic considerations have caused the permanent shutdown of a fourth plant. Additionally, several utilities have cancelled power uprate projects citing economic concerns. For the past several years net electrical generation from U.S. nuclear power plants has been declining. One of few remaining areas where significant improvements in plant capacity factors can be made is in minimizing the duration of refueling outages. Managing nuclear power plant outages is a complex and difficult task. Due to the large number of complex tasks and the uncertainty that accompanies them, outage durations routinely exceed the planned duration. The ability to complete an outage on or near

Nuclear power plant outage optimisation strategy

International Nuclear Information System (INIS)

2002-10-01

Competitive environment for electricity generation has significant implications for nuclear power plant operations, including among others the need of efficient use of resources, effective management of plant activities such as on-line maintenance and outages. Nuclear power plant outage management is a key factor for good, safe and economic nuclear power plant performance which involves many aspects: plant policy, co-ordination of available resources, nuclear safety, regulatory and technical requirements and, all activities and work hazards, before and during the outage. This technical publication aims to communicate these practices in a way they can be used by operators and utilities in the Member States of the IAEA. It intends to give guidance to outage managers, operating staff and to the local industry on planning aspects, as well as examples and strategies experienced from current plants in operation on the optimization of outage period. This report discusses the plant outage strategy and how this strategy is actually implemented. The main areas identified as most important for outage optimization by the utilities and government organizations participating in this report are: organization and management; outage planning and preparation, outage execution, safety outage review, and counter measures to avoid extension of outages and to easier the work in forced outages. This report was based on discussions and findings by the authors of the annexes and the participants of an Advisory Group Meeting on Determinant Causes for Reducing Outage Duration held in June 1999 in Vienna. The report presents the consensus of these experts regarding best common or individual good practices that can be used at nuclear power plants with the aim to optimize

Control practices contribute to premature transformer failures

Energy Technology Data Exchange (ETDEWEB)

Jauch, E.T. [Beckwith Electric Company Inc., Largo, FL (United States)

2007-07-01

Studies of premature load tap changer (LTC) transformer failures on utility systems have shown the tap changers to be the primary contributing factor. Some of the LTC factors that lead to transformer failures include oil quality and particulate contamination; LTC contact temperature rise; contact coking; carbon film build-up; short circuit mechanical forces; and contact wear and arcing. These factors create increasing contact resistance thereby increasing voltage drop, localized heating, contact pitting, oil contamination and general deterioration. This paper discussed utility tapchanger control practices and methods of determining control functions to be activated as well as the determination of optimum settings contributing to excessive or untimely tap change operations. The transformer applications that were considered included transmission tie transformers as well as transmission distribution interface transformers. The paper discussed the circulating current paralleling method and the circulating reactive current or var sharing paralleling method. Several common practices were discussed, including basic voltage control ranges and setting effects; timing options available; LDC misapplications; first house protection methods; and various paralleling techniques. It was concluded that although there are several other methods of paralleling power transformers, many are not applicable under certain system configurations. In these applications, improper use of a paralleling method or improper setting and commissioning may cause hunting for appropriate tap positions and dramatically increase the number of tap changes, causing wear and degradation of the tap changer contacts. 3 refs., 5 figs.

Outage reduction of Hamaoka NPS

International Nuclear Information System (INIS)

Hida, Shigeru; Anma, Minoru

1999-01-01

In the Hamaoka nuclear power plant, we have worked on the outage reduction since 1993. In those days, the outage length in Hamaoka was 80 days or more, and was largely far apart from excellent results of European and American plants about the 30days. A concrete strategy to achieve the reduction process is the extension of working hours, the changing work schedule control unit for every hour, the equipment improvements, and the improvements of work environments, etc. We executed them one by one reflecting results. As a result, we achieved the outage for 57 days in 1995. Starting from this, we acquired the further outage reduction one by one and achieved the outage for 38 days in 1997 while maintaining safety and reliability of the plant. We advance these strategies further and we will aim at the achievement of the 30·35 days outage in the future. (author)

Outage optimization - the US experience and approach

International Nuclear Information System (INIS)

LaPlatney, J.

2007-01-01

Sustainable development of Nuclear Energy depends heavily on excellent performance of the existing fleet which in turn depends heavily on the performance of planned outages. Some reactor fleets, for example Finland and Germany, have demonstrated sustained good outage performance from their start of commercial operation. Others, such as the US, have improved performance over time. The principles behind a successful outage optimization process are: -) duration is not sole measure of outage success, -) outage work must be performed safely, -) scope selection must focus on improving plant material condition to improve reliability, -) all approved outage work must be completed, -) work must be done cost effectively, -) post-outage plant reliability is a key measure of outage success, and -) outage lessons learned must be effectively implemented to achieve continuous improvement. This approach has proven its superiority over simple outage shortening, and has yielded good results in the US fleet over the past 15 years

Nuclear Plant Integrated Outage Management

International Nuclear Information System (INIS)

Gerstberger, C. R.; Coulehan, R. J.; Tench, W. A.

1992-01-01

This paper is a discussion of an emerging concept for improving nuclear plant outage performance - integrated outage management. The paper begins with an explanation of what the concept encompasses, including a scope definition of the service and descriptions of the organization structure, various team functions, and vendor/customer relationships. The evolvement of traditional base scope services to the integrated outage concept is addressed and includes discussions on changing customer needs, shared risks, and a partnership approach to outages. Experiences with concept implementation from a single service in 1984 to the current volume of integrated outage management presented in this paper. We at Westinghouse believe that the operators of nuclear power plants will continue to be aggressively challenged in the next decade to improve the operating and financial performance of their units. More and more customers in the U. S. are looking towards integrated outage as the way to meet these challenges of the 1990s, an arrangement that is best implemented through a long-term partnering with a single-source supplier of high quality nuclear and turbine generator outage services. This availability, and other important parameters

Outage management philosophies at Oconee nuclear station

International Nuclear Information System (INIS)

Bond, R.T.

1991-01-01

At Oconee the biggest single factor in improving availability and cutting cost per kilowatt-hour is reducing outage lengths. This must be accomplished without compromising the quality of the work that must be performed during these outages. Oconee has completed 35 refueling outages and has gained considerable experience in outage management. Since 1984, outage costs and durations have consistently been reduced while continuing to improve capacity factors. The last 6 refueling outages were 43, 42, 45, 42, 41, and 44 days, respectively. The capacity factors for these units between refueling outages are 98, 94, 96, 98, and 98%, respectively. The average cost of outages has been less than $12 million. It is believed that success cannot be attributed to any one factor by itself but is a compilation of many factors, all complementing each other. It is also believed, however, that there are four key areas that represent philosophies and can be given most of the credit for successful outages: planning, experience, teamwork, and outage management

Management techniques that keep outages on schedule

International Nuclear Information System (INIS)

Taylor, R.B.

1987-01-01

During the immature operation of the Pickering Units 5 through 8, significant numbers of outages have been required to deal with warranty inspections and equipment problems. Techniques have been developed to ensure that outages are properly planned and managed so that outage time is minimized, overtime is minimized, and capacity factor is maximized, while ensuring that personnel safety is not compromised. Successful outage planning and execution requires the commitment of many on-station and off-station resources groups. Coordination of all of these groups is required both before and during the outage to ensure outage time is not lost due to unavailability of men or equipment at the time they are required. This paper details the control processes that must be used prior to, during, and after an outage to ensure that time is not lost unnecessarily during outages. Successful outage management at Pickering Nuclear Generating Station can be subdivided into three stages; preoutage planning, outage execution, and postoutage review

Integrated outage management: Leveraging utility system assets including GIS and AMR for optimum outage response

Energy Technology Data Exchange (ETDEWEB)

Finamore, E. P.

2004-02-01

The control of electrical system outages is discussed. The principal argument advanced is that traditional stand-alone methods of outage response will no longer get the job done without utility companies integrating their outage management systems with other system assets such as GIS (geographic information system) and AMR (advanced metering systems). Many meter reading systems, while primarily supporting customer billing, can also provide outage alarm and some are also capable of service restoration notification, which is an invaluable benefit to service operators since it obviates the need for verifying system restoration by labour-intensive on-site visits or customer call-backs. If successfully leveraged, optimization of all utility assets and improvements in labour productivity can results in improved outage management performance gains without affecting performance in other areas.

Nuclear power plant outages

International Nuclear Information System (INIS)

1998-01-01

The Finnish Radiation and Nuclear Safety Authority (STUK) controls nuclear power plant safety in Finland. In addition to controlling the design, construction and operation of nuclear power plants, STUK also controls refuelling and repair outages at the plants. According to section 9 of the Nuclear Energy Act (990/87), it shall be the licence-holder's obligation to ensure the safety of the use of nuclear energy. Requirements applicable to the licence-holder as regards the assurance of outage safety are presented in this guide. STUK's regulatory control activities pertaining to outages are also described

Nuclear Power Plant Outage Optimization Strategy. 2016 Edition

International Nuclear Information System (INIS)

2016-10-01

This publication is an update of IAEA-TECDOC-1315, Nuclear Power Plant Outage Optimisation Strategy, which was published in 2002, and aims to communicate good outage management practices in a manner that can be used by operators and utilities in Member States. Nuclear power plant outage management is a key factor for safe and economic nuclear power plant performance. This publication discusses plant outage strategy and how this strategy is actually implemented. The main areas that are important for outage optimization that were identified by the utilities and government organizations participating in this report are: 1) organization and management; 2) outage planning and preparation; 3) outage execution; 4) safety outage review; and 5) counter measures to avoid the extension of outages and to facilitate the work in forced outages. Good outage management practices cover many different areas of work and this publication aims to communicate these good practices in a way that they can be used effectively by operators and utilities

Placental Inflammatory Changes and Bacterial Infection in Premature Neonates with Respiratory Failure

Directory of Open Access Journals (Sweden)

S. A. Perepelitsa

2012-01-01

Full Text Available Objective: to reveal a relationship of placental inflammatory changes to bacterial infection in premature neonates with respiratory failure. Material and methods. Bronchoalveolar aspirate was bacteriologically studied in 157 premature neonates with respiratory distress syndrome (NRDS; the total and differential leukocyte counts were measured in their peripheral blood. The levels of the cytokines IL-1^3, IL-4, IL-6, and TNF-a were studied in different biological fluids of mothers and their babies; the placentas were also morphologically examined. Results. An analysis of bacterial cultures from the tracheobronchial tree revealed no growth of bacterial microflora in 61.8% of cases, Enterococcus faecalis and Staphylococcus epidermidis were isolated in 6.4 and 8.3% of the infants, respectively; Staphylococcus haemolyticus, Staphylococcus capitis, Enterobacter agglomerans, and hemolytic group A Streptococcus were seen in 1.9% each; moreover, 1.3% of the newborn infants were found to have Bacillus spp., Staphylococcus aureus, Escherichia coli, Acinetobacter spp., and Serratia marcescens. Other microorganisms and a microbial association were encountered in 8.9% of cases. Placental morphological examination revealed different inflammatory changes concurrent with chronic and acute placental insufficiency. The investigation demonstrated that the maternal peripheral plasma levels of IL-1^, IL-4, IL-6, and TNF-a were within the physiological range at the end of the first period of delivery. The amniotic fluid displayed elevated IL-6 and TNF-a concentrations and normal IL-4 and IL-1e levels, suggesting that there was an intrauterine inflammatory process. Conclusion. Premature birth is associated with various placental inflammatory changes, which causes intrauterine stimulation of macrophages in the chorionic villi. Specific immune defense mechanisms that prevent the development of a fetal infectious process, i.e. the maternal infectious process, may induce

Development of Improved Graphical Displays for an Advanced Outage Control Center, Employing Human Factors Principles for Outage Schedule Management

Energy Technology Data Exchange (ETDEWEB)

St Germain, Shawn Walter [Idaho National Lab. (INL), Idaho Falls, ID (United States); Farris, Ronald Keith [Idaho National Lab. (INL), Idaho Falls, ID (United States); Thomas, Kenneth David [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-09-01

The long-term viability of existing nuclear power plants in the United States (U.S.) is dependent upon a number of factors, including maintaining high capacity factors, maintaining nuclear safety, and reducing operating costs, particularly those associated with refueling outages. Refueling outages typically take 20-30 days, and for existing light water NPPs in the U.S., the reactor cannot be in operation during the outage. Furthermore, given that many NPPs generate between $1-1.5 million/day in revenue when in operation, there is considerable interest in shortening the length of refueling outages. Yet refueling outages are highly complex operations, involving multiple concurrent and dependent activities that are somewhat challenging to coordinate; therefore, finding ways to improve refueling outage performance, while maintaining nuclear safety has proven to be difficult. The Advanced Outage Control Center (AOCC) project is a research and development (R&D) demonstration activity under the LWRS Program. LWRS is an R&D program that works closely with industry R&D programs to establish technical foundations for the licensing and managing of long-term, safe, and economical operation of current fleet of NPPs. As such, the LWRS Advanced Outage Control Center project has the goal of improving the management of commercial NPP refueling outages. To accomplish this goal, INL is developing an advanced outage control center (OCC) that is specifically designed to maximize the usefulness of communication and collaboration technologies for outage coordination and problem resolution activities. The overall focus is on developing an AOCC with the following capabilities that enables plant and OCC staff to; Collaborate in real-time to address emergent issues; Effectively communicate outage status to all workers involved in the outage; Effectively communicate discovered conditions in the field to the OCC; Provide real-time work status; Provide automatic pending support notifications

Development of Improved Graphical Displays for an Advanced Outage Control Center, Employing Human Factors Principles for Outage Schedule Management

International Nuclear Information System (INIS)

St Germain, Shawn Walter; Farris, Ronald Keith; Thomas, Kenneth David

2015-01-01

The long-term viability of existing nuclear power plants in the United States (U.S.) is dependent upon a number of factors, including maintaining high capacity factors, maintaining nuclear safety, and reducing operating costs, particularly those associated with refueling outages. Refueling outages typically take 20-30 days, and for existing light water NPPs in the U.S., the reactor cannot be in operation during the outage. Furthermore, given that many NPPs generate between $1-1.5 million/day in revenue when in operation, there is considerable interest in shortening the length of refueling outages. Yet refueling outages are highly complex operations, involving multiple concurrent and dependent activities that are somewhat challenging to coordinate; therefore, finding ways to improve refueling outage performance, while maintaining nuclear safety has proven to be difficult. The Advanced Outage Control Center (AOCC) project is a research and development (R&D) demonstration activity under the LWRS Program. LWRS is an R&D program that works closely with industry R&D programs to establish technical foundations for the licensing and managing of long-term, safe, and economical operation of current fleet of NPPs. As such, the LWRS Advanced Outage Control Center project has the goal of improving the management of commercial NPP refueling outages. To accomplish this goal, INL is developing an advanced outage control center (OCC) that is specifically designed to maximize the usefulness of communication and collaboration technologies for outage coordination and problem resolution activities. The overall focus is on developing an AOCC with the following capabilities that enables plant and OCC staff to; Collaborate in real-time to address emergent issues; Effectively communicate outage status to all workers involved in the outage; Effectively communicate discovered conditions in the field to the OCC; Provide real-time work status; Provide automatic pending support notifications

Placement of Synchronized Measurements for Power System Observability during Cascaded Outages

Science.gov (United States)

Thirugnanasambandam, Venkatesh; Jain, Trapti

2017-11-01

Cascaded outages often result in power system islanding followed by a blackout and therefore considered as a severe disturbance. Maintaining the observability of each island may help in taking proper control actions to preserve the stability of individual islands thus, averting system collapse. With this intent, a strategy for placement of synchronized measurements, which can be obtained from phasor measurement units (PMU), has been proposed in this paper to keep the system observable during cascaded outages also. Since, all the cascaded failures may not lead to islanding situations, therefore, failures leading to islanding as well as non-islanding situations have been considered. A topology based algorithm has been developed to identify the islanding/non-islanding condition created by a particular cascaded event. Additional contingencies such as single line loss and single PMU failure have also been considered after the occurrence of cascaded events. The proposed method is further extended to incorporate the measurement redundancy, which is desirable for a reliable state estimation. The proposed scheme is tested on IEEE 14-bus, IEEE 30-bus and a practical Indian 246-bus networks. The numerical results ensure the observability of the power system under system intact as well as during cascaded islanding and non-islanding disturbances.

OVULATION INDUCTION IN PREMATURE OVARIAN FAILURE - A PLACEBO-CONTROLLED RANDOMIZED TRIAL COMBINING PITUITARY SUPPRESSION WITH GONADOTROPIN STIMULATION

NARCIS (Netherlands)

VANKASTEREN, YM; HOEK, A; SCHOEMAKER, J

Objectives: To determine the effect of pituitary suppression with a GnRH agonist (GnRH-a) on the success of ovulation induction with exogenous gonadotropins in patients with premature ovarian failure (POF). Design: Placebo-controlled, randomized, double-blind study. The data were analyzed with a

Outages planning

International Nuclear Information System (INIS)

Blanquer, N.

2010-01-01

The reason of a nuclear power plant outage seems easy. Replace 1/3 of the total core fuel inside reactor for a new, store the old one in a pool and shuffle the rest 2/3 in other positions in the core to optimize fuel burn up. Also is needed to make the preventive, corrective and conservative maintenance, the selected design changes and the regulatory and technical requirements for equipment and systems. To make the plant outage strategy for all the above pack with nuclear safety not challenged is the objective of this article for the Spanish Nuclear Society magazine. (Author)

Polymorphisms within the FANCA gene associate with premature ovarian failure in Korean women.

Science.gov (United States)

Pyun, Jung-A; Kim, Sunshin; Cha, Dong Hyun; Kwack, KyuBum

2014-05-01

This study investigated whether polymorphisms within the Fanconi anemia complementation group A (FANCA) gene contribute to the increased risk of premature ovarian failure (POF) in Korean women. Ninety-eight women with POF and 218 controls participated in this study. Genomic DNA from peripheral blood was isolated, and GoldenGate genotyping assay was used to identify single nucleotide polymorphisms (SNPs) within the FANCA gene. Two significant SNPs (rs1006547 and rs2239359; P FANCA gene may increase the risk for POF in Korean women.

Review of Paks outage results 1990

International Nuclear Information System (INIS)

Lukacs, P.; Zsoldos, F.; Kiss, Z.

1991-01-01

The year 1990 was not the most successful from an outage point of view at the Paks Nuclear Power Plant in Hungary -there were one or two long delays. Work at unit 4 had a delay of 10 days because of an error made during assembling the reactor vessel. While the outage of unit 3 was running, a feedwater pipe hanger problem was discovered - several hangers were found displaced from the right position. A general inspection of the affected system was required and this took about 11 days. Information about each outage is presented on diagrams, making comparison easier. These diagrams give information about deviations from the outage plan, about work hours performed during outages, and about collective exposure. (author)

Comparison and validation of statistical methods for predicting power outage durations in the event of hurricanes.

Science.gov (United States)

Nateghi, Roshanak; Guikema, Seth D; Quiring, Steven M

2011-12-01

This article compares statistical methods for modeling power outage durations during hurricanes and examines the predictive accuracy of these methods. Being able to make accurate predictions of power outage durations is valuable because the information can be used by utility companies to plan their restoration efforts more efficiently. This information can also help inform customers and public agencies of the expected outage times, enabling better collective response planning, and coordination of restoration efforts for other critical infrastructures that depend on electricity. In the long run, outage duration estimates for future storm scenarios may help utilities and public agencies better allocate risk management resources to balance the disruption from hurricanes with the cost of hardening power systems. We compare the out-of-sample predictive accuracy of five distinct statistical models for estimating power outage duration times caused by Hurricane Ivan in 2004. The methods compared include both regression models (accelerated failure time (AFT) and Cox proportional hazard models (Cox PH)) and data mining techniques (regression trees, Bayesian additive regression trees (BART), and multivariate additive regression splines). We then validate our models against two other hurricanes. Our results indicate that BART yields the best prediction accuracy and that it is possible to predict outage durations with reasonable accuracy. © 2011 Society for Risk Analysis.

Guidelines for Implementation of an Advanced Outage Control Center to Improve Outage Coordination, Problem Resolution, and Outage Risk Management

Energy Technology Data Exchange (ETDEWEB)

St. Germain, Shawn W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Farris, Ronald K. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Whaley, April M. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Medema, Heather D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gertman, David I. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2014-09-01

This research effort is a part of the Light-Water Reactor Sustainability (LWRS) Program, which is a research and development (R&D) program sponsored by Department of Energy (DOE) and performed in close collaboration with industry R&D programs that provide the technical foundations for licensing and managing the long-term, safe, and economical operation of current nuclear power plants. The LWRS program serves to help the U.S. nuclear industry adopt new technologies and engineering solutions that facilitate the continued safe operation of the plants and extension of the current operating licenses. The purpose of this research is to improve management of nuclear power plant (NPP) outages through the development of an advanced outage control center (AOCC) that is specifically designed to maximize the usefulness of communication and collaboration technologies for outage coordination and problem resolution activities. This technical report for industry implementation outlines methods and considerations for the establishment of an AOCC. This report provides a process for implementation of a change management plan, evaluation of current outage processes, the selection of technology, and guidance for the implementation of the selected technology. Methods are presented for both adoption of technologies within an existing OCC and for a complete OCC replacement, including human factors considerations for OCC design and setup.

Framatome ANP outage optimization support solutions

International Nuclear Information System (INIS)

Bombail, Jean Paul

2003-01-01

Over the last several years, leading plant operators have demonstrated that availability factors can be improved while safety and reliability can be enhanced on a long-term basis and operating costs reduced. Outage optimization is the new term being used to describe these long-term initiatives through which a variety of measures aimed at shortening scheduled plant outages have been developed and successfully implemented by these leaders working with their service providers who were introducing new technologies and process improvements. Following the leaders, all operators now have ambitious outage optimization plans and the median and average outage duration are decreasing world-wide. Future objectives are even more stringent and must include plant upgrades and component replacements being performed for life extension of plant operation. Outage optimization covers a broad range of activities from modifications of plant systems to faster cool down rates to human behavior improvements. It has been proven to reduce costs, avoid unplanned outages and thus support plant availability and help to ensure the utility's competitive position in the marketplace

Management strategies for nuclear power plant outages

International Nuclear Information System (INIS)

2006-01-01

More competitive energy markets have significant implications for nuclear power plant operations, including, among others, the need for more efficient use of resources and effective management of plant activities such as on-line maintenance and outages. Outage management is a key factor for safe, reliable and economic plant performance and involves many aspects: plant policy, coordination of available resources, nuclear safety, regulatory and technical requirements, and all activities and work hazards, before and during the outage. The IAEA has produced this report on nuclear power plant outage management strategies to provide both a summary and an update of a follow-up to a series of technical documents related to practices regarding outage management and cost effective maintenance. The aim of this publication is to identify good practices in outage management: outage planning and preparation, outage execution and post-outage review. As in in the related technical documents, this report aims to communicate these practices in such a way that they can be used by operating organizations and regulatory bodies in Member States. The report was prepared as part of an IAEA project on continuous process improvement. The objective of this project is to increase Member State capabilities in improving plant performance and competitiveness through the utilization of proven engineering and management practices developed and transferred by the IAEA

CSB-PGBD3 Mutations Cause Premature Ovarian Failure.

Directory of Open Access Journals (Sweden)

Yingying Qin

2015-07-01

Full Text Available Premature ovarian failure (POF is a rare, heterogeneous disorder characterized by cessation of menstruation occurring before the age of 40 years. Genetic etiology is responsible for perhaps 25% of cases, but most cases are sporadic and unexplained. In this study, through whole exome sequencing in a non-consanguineous family having four affected members with POF and Sanger sequencing in 432 sporadic cases, we identified three novel mutations in the fusion gene CSB-PGBD3. Subsequently functional studies suggest that mutated CSB-PGBD3 fusion protein was impaired in response to DNA damage, as indicated by delayed or absent recruitment to damaged sites. Our data provide the first evidence that mutations in the CSB-PGBD3 fusion protein can cause human disease, even in the presence of functional CSB, thus potentially explaining conservation of the fusion protein for 43 My since marmoset. The localization of the CSB-PGBD3 fusion protein to UVA-induced nuclear DNA repair foci further suggests that the CSB-PGBD3 fusion protein, like many other proteins that can cause POF, modulates or participates in DNA repair.

Outage risk reduction at Diablo Canyon

International Nuclear Information System (INIS)

Burnett, Tobias W.T.; Eugene Newman, C.

2004-01-01

A formal risk reduction program was conducted at the Diablo Canyon Nuclear Generating plant as part of EPRI's Outage Risk Assessment and Management Program. The program began with a probabilistic and deterministic assessment of the frequency of core coolant boiling and core uncovery during shutdown operations. This step identified important contributors to risk, periods of high vulnerability, and potential mechanisms for reducing risk. Next, recovery strategies were evaluated and procedures, training, and outage schedules modified. Twelve risk reduction enhancements were developed and implemented. These enhancements and their impact are described in this paper. These enhancements reduced the calculated risk of core uncovery by about a factor of four for a refueling outage without lengthening the outage schedule; increased the outage efficiency, contributing to completing 11 days ahead of schedule; and helped to earn the highest achievable SALP rating from the NRC. (author)

Outage scheduling and implementation

International Nuclear Information System (INIS)

Allison, J.E.; Segall, P.; Smith, R.R.

1986-01-01

Successful preparation and implementation of an outage schedule and completion of scheduled and emergent work within an identified critical path time frame is a result of careful coordination by Operations, Work Control, Maintenance, Engineering, Planning and Administration and others. At the Fast Flux Test Facility (FFTF) careful planning has been responsible for meeting all scheduled outage critical paths

A case of premature ovarian failure (POF) in a 31-year-old woman with a 47,XXX karyotype.

Science.gov (United States)

Skałba, Piotr; Cygal, Anna; Gierzyńska, Zuzanna

2010-01-01

A case of POF in a 31-year-old woman with karyotype 47,XXX. The aim of the study was to discuss a case of POF in a 31-year-old patient with polysomy 47,XXX. The described karyotype is not usually associated with this characteristic physical phenotype. In some rare cases, menstrual disorders, sterility, secondary amenorrhoea, premature menopause, and low intelligence are found. Our observations revealed the necessity for cytogenetic examination in all women at reproductive age with symptoms of premature ovarian failure. According to the data found in literature, patients with POF and karyotype disorders belong to the risk group of premature death, mostly for cardiological reasons. Raising patient awareness about the risk may have a positive effect on quality of life and regularity of check-ups.

Qinshan CANDU NPP outage performance improvement through benchmarking

International Nuclear Information System (INIS)

Jiang Fuming

2005-01-01

With the increasingly fierce competition in the deregulated Energy Market, the optimization of outage duration has become one of the focal points for the Nuclear Power Plant owners around the world. People are seeking various ways to shorten the outage duration of NPP. Great efforts have been made in the Light Water Reactor (LWR) family with the concept of benchmarking and evaluation, which great reduced the outage duration and improved outage performance. The average capacity factor of LWRs has been greatly improved over the last three decades, which now is close to 90%. CANDU (Pressurized Heavy Water Reactor) stations, with its unique feature of on power refueling, of nuclear fuel remaining in the reactor all through the planned outage, have given raise to more stringent safety requirements during planned outage. In addition, the above feature gives more variations to the critical path of planned outage in different station. In order to benchmarking again the best practices in the CANDU stations, Third Qinshan Nuclear Power Company (TQNPC) have initiated the benchmarking program among the CANDU stations aiming to standardize the outage maintenance windows and optimize the outage duration. The initial benchmarking has resulted the optimization of outage duration in Qinshan CANDU NPP and the formulation of its first long-term outage plan. This paper describes the benchmarking works that have been proven to be useful for optimizing outage duration in Qinshan CANDU NPP, and the vision of further optimize the duration with joint effort from the CANDU community. (authors)

Telomeres, telomerase and premature ovarian failure

Directory of Open Access Journals (Sweden)

Renata Košir Pogačnik

2011-11-01

Full Text Available Telomeres are specialized structures at the ends of chromosomes, consisting of six repeated nucleotides in TTAGGG sequence. Genome stability is partly maintained by the architecture of telomeres and is gradually lost as telomeres progressively shorten with each cell replication. Critically shortened telomeres are recognized by DNA repair mechanisms as DNA damage and the cell replication cycle stops. The cell eventually dies or undergoes cell apoptosis. Telomere represents a cellular marker of biological age and are therefore also called cell mitotic clock. The enzyme that counteracts telomere shortening by adding nucleotides to the 3’ end of DNA strand is called telomerase. It is composed of the RNA subunit (TR, which is special type of messenger RNA (mRNA, the catalytic protein subunit (TERT, which works as a reverse transcriptase and numerous additional proteins. Telomerase is active in some germline, epithelial and haemopoietic cells, but in most somatic cells the activity is undetectable. In literature, the length of telomeres is closely connected with premature ovarian failure (POF. POF is generally defined as the onset of menopause before the age of 40. The causes of disease are genetical, autoimmune, iatrogenic or if we cannot establish the cause – idiopathic. A lot of studies examined correlation between idiopathic POF, length of telomeres and telomerase activity. The studies mostly show that women with POF have shortened telomeres and decreased activity of telomerase as compared to healthy women.

How individual traces and interactive timelines could support outage execution - Toward an outage historian concept

International Nuclear Information System (INIS)

Parfouru, S.; De-Beler, N.

2012-01-01

In the context of a project that is designing innovative ICT-based solutions for the organizational concept of outage management, we focus on the informational process of the OCR (Outage Control Room) underlying the execution of the outages. Informational process are based on structured and unstructured documents that have a key role in the collaborative processes and management of the outage. We especially track the structured and unstructured documents, electronically or not, from creation to sharing. Our analysis allows us to consider that the individual traces produced by an individual participant with a specific role could be multi-purpose and support sharing between participants without creating duplication of work. The ultimate goal is to be able to generate an outage historian, that is not just focused on highly structured information, which could be useful to improve the continuity of information between participants. We study the implementation of this approach through web technologies and social media tools to address this issue. We also investigate the issue of data access through interactive visualization timelines coupled with other modality's to assist users in the navigation and exploration of the proposed historian. (authors)

Major outage trends in light water reactors. Interim report

International Nuclear Information System (INIS)

Burns, E.T.

1978-04-01

The report is a summary of the major outages which occurred in light water reactor plants during the period January 1971 through June 1977. Only those outages greater than 100 hours duration (exclusive of refueling outages) are included in the report. The trends in outages related to various reactor systems and components are presented as a function of plant age, and alternatively, calendar year. The principal contributors to major outages are ranked by their effect on the overall outage time for PWRs and BWRs. In addition, the outage history of each operating nuclear plant greater than 150 MWe is presented, along with a brief summary of those outages greater than two months duration

Advanced Test Reactor outage risk assessment

International Nuclear Information System (INIS)

Thatcher, T.A.; Atkinson, S.A.

1997-01-01

Beginning in 1997, risk assessment was performed for each Advanced Test Reactor (ATR) outage aiding the coordination of plant configuration and work activities (maintenance, construction projects, etc.) to minimize the risk of reactor fuel damage and to improve defense-in-depth. The risk assessment activities move beyond simply meeting Technical Safety Requirements to increase the awareness of risk sensitive configurations, to focus increased attention on the higher risk activities, and to seek cost-effective design or operational changes that reduce risk. A detailed probabilistic risk assessment (PRA) had been performed to assess the risk of fuel damage during shutdown operations including heavy load handling. This resulted in several design changes to improve safety; however, evaluation of individual outages had not been performed previously and many risk insights were not being utilized in outage planning. The shutdown PRA provided the necessary framework for assessing relative and absolute risk levels and assessing defense-in-depth. Guidelines were written identifying combinations of equipment outages to avoid. Screening criteria were developed for the selection of work activities to receive review. Tabulation of inherent and work-related initiating events and their relative risk level versus plant mode has aided identification of the risk level the scheduled work involves. Preoutage reviews are conducted and post-outage risk assessment is documented to summarize the positive and negative aspects of the outage with regard to risk. The risk for the outage is compared to the risk level that would result from optimal scheduling of the work to be performed and to baseline or average past performance

International outage coding system for nuclear power plants. Results of a co-ordinated research project

International Nuclear Information System (INIS)

2004-05-01

The experience obtained in each individual plant constitutes the most relevant source of information for improving its performance. However, experience of the level of the utility, country and worldwide is also extremely valuable, because there are limitations to what can be learned from in-house experience. But learning from the experience of others is admittedly difficult, if the information is not harmonized. Therefore, such systems should be standardized and applicable to all types of reactors satisfying the needs of the broad set of nuclear power plant operators worldwide and allowing experience to be shared internationally. To cope with the considerable amount of information gathered from nuclear power plants worldwide, it is necessary to codify the information facilitating the identification of causes of outages, systems or component failures. Therefore, the IAEA established a sponsored Co-ordinated Research Project (CRP) on the International Outage Coding System to develop a general, internationally applicable system of coding nuclear power plant outages, providing worldwide nuclear utilities with a standardized tool for reporting outage information. This TECDOC summarizes the results of this CRP and provides information for transformation of the historical outage data into the new coding system, taking into consideration the existing systems for coding nuclear power plant events (WANO, IAEA-IRS and IAEA PRIS) but avoiding duplication of efforts to the maximum possible extent

Nuclear outages: an approach to project controls

International Nuclear Information System (INIS)

Bryson, R.

1985-01-01

The annual budget for maintaining and operating a nuclear power plant has risen dramatically over the past 5 years. NRC-mandated plant improvements and outage related expenses are often cited to be the main contributors to these escalating budgets. Nuclear utilities have responded by developing programs to improve plant availability and outage costs through improved outage performance. Utilities recognize that for capital improvements the program to control costs does no begin with outage planning, but rather more appropriately up front during the engineering phase. To support their management objectives, utilities have been developing comprehensive project control systems for concurrently reducing capital expenditures, outage-related costs, and time. This paper provides an approach to project controls that, rather than using one all inclusive comprehensive system, requires five separate monitoring systems - one for each phase of an activity's life cycle. Through the integration of these discrete but interrelated systems, utility management acquires the necessary tools for comprehensive planning and control of their modification program and effective detailed monitoring for all outage-related activities

Outage Risk Assessment and Management (ORAM) technology to improve outage safety and economics

International Nuclear Information System (INIS)

Kalra, S.P.

2004-01-01

The Electric Power Research Institute (EPRI) has undertaken an aggressive program, called ORAM (Outage Risk Assessment and Management), to provide utilities with tools and technology to assist in managing risk during the planning and conduct of outages. The ORAM program consists of the following 6 steps: i) Perform utility surveys and visits on shutdown risk management needs, ii) Perform probabilistic shutdown safety assessments (PSSAs) to identify generic insights that can be incorporated into risk management guidelines and identify selected areas for the development of contingency actions, iii) Develop risk management guidelines (RMG's) that provide a systematic approach to the planning and conduct of outages from a safety perspective. Incorporate insights from the shutdown safety assessments and other operating experience into the RMG's. iv) Develop selected contingency actions including a thermalhydraulic tool kit to address higher risk time periods and activities identified in the shutdown safety assessments, v) Develop computer software that integrates all of the above capability into an easy to use tool for effective shutdown operation management for utilities, vi) Provide assistance in the transfer of this technology and the application of these tools. This paper briefly describes the technical approach and tools developed under EPRI's ORAM program and its applications for improving outage safety and economics. (author)

Standard plants, standard outages: the EdF approach

International Nuclear Information System (INIS)

Miron, J.L.

1991-01-01

At the end of 1990 Electricite de France had carried out a total of 350 PWR refuelling outages. Although the French units are standardized the routine of the outages are not all the same. The major influences on outages were: setting up new organizations to apply quality assurance regulations; improving systematic experience feedback; incorporating modifications in the outage schedules; assumilation of computerized maintenance management by the sites. (author)

Primary Water Chemistry Control during a Planned Outage at Bruce Power

International Nuclear Information System (INIS)

Ma, Guoping; Nashiem, Rod; Matheson, Shane; Yabar, Berman; Harper, Bill; Roberts, John G.

2012-09-01

Bruce Power has developed a comprehensive outage water chemistry program, which includes both primary and secondary chemistry requirements during planned outages. The purpose of the program is to emphasize the chemistry requirements during outages and subsequent start-ups in order to maintain the integrity of the systems, minimise activity transport and radiation fields, reduce the Carbon-14 release, and to ensure that the requirements are integrated with the outage management program. Prior to a planned outage, Station Chemical Technical Sections identify outage chemistry requirements to Operations and Outage Planning and ensure that work necessary to correct system chemistry issues is within outage work scope. The outage water chemistry program provides direction for establishing alternative sampling locations as demanded by the system configuration during the outage and identifies outage prerequisites for nuclear system purification capabilities. These requirements are contained in an outage checklist. The paper mainly highlights the primary water chemistry issues and chemistry control strategies during planned outages and discusses challenges and successes. (authors)

Integrated outages increase Surry's availability

International Nuclear Information System (INIS)

Harms, S.R.; Downs, J.L.

1995-01-01

This article describes how, through Virginia Power's and Westinghouse's goal-oriented planning philosophy, teamwork and commitment, average outage duration has decreased significantly. During the past 10 years Virginia Power and its nuclear steam supply system (NSSS) services vendor, Westinghouse Electric Corp., have developed a working partnership with one goal in mind: increasing the availability and capacity factors of the North Anna and Surry nuclear power stations while driving down the operating costs of the plants. The outage integration program, steam generator maintenance agreement (SGMA), and integrated radiological services program form the core of this relationship and helped Virginia Power complete one of the most successful outages in Surry Power Station's operating history

Maintenance and Outage Management Assessment (MOMA)

International Nuclear Information System (INIS)

2005-01-01

The competitive environment has significant implications for nuclear power plant (NPP) operations, which include, inter alia, the need for efficient use of resources and effective management of plant activities of maintenance and outages. The purpose of NPP maintenance and outages is to allow NPPs to use all those functions necessary for safe and reliable power production by keeping them available and adequate maintenance programme is essential. The maintenance programme covers all preventive and remedial measures, both administrative and technical, necessary to identify and mitigate degradation of a functioning system, structure or component, or restore the design functions of a failed system, structure or component to an acceptable level. In response to the needs of MSs, NPES (Nuclear Power Section, Division of Nuclear Power, IAEA) plans to strengthen its services. NPES services will not only continue to provide its 'traditional' products of publications of nuclear industrial best practices and technical implementation of TC projects on plant maintenance and outage management, but also be expanded to deliver, in a timely manner, technical support missions as requested by MSs for NPPs. One of many services is Maintenance and Outage Management Assessment (MOMA). The NPP can obtain support and assistance in assessment and optimisation of its maintenance program and/or outage management. It aims to help the NPP improve its performance of maintenance and outage in a competitive nuclear power business environment. The specific benefits of the assessment are as follows: a) disseminate nuclear industrial best practices on maintenance program and outage management in the world, b) benchmark, evaluate and optimise the approach of maintenance program and outage management and c) identify solutions to known problems at nuclear power plants, if any. MOMA is conducted at the request of NPPs of any IAEA Member States. MOMA consists in a technical mission/visit for 1-3 weeks by

Reactor refurbishment in an outage environment

International Nuclear Information System (INIS)

Gowthorpe, P.; Hoare, R.

2012-01-01

Reactor life extension has typically been performed during specific refurbishment outages. These outages are long and costly due to the sheer complexity of the scope, not to mention the ever present discovery work. A scope of this size requires a huge labour force to execute, which poses significant challenges. The work is difficult to staff with qualified people able to execute the work smoothly and managing the required labour pool problematic. Cost and time overruns are inevitable in that environment. Reducing the cost and schedule is critical to the long term viability of reactor refurbishment projects. With planning, the total cost of the refurbishment can be reduced by managing the inspection and repairs during normal outages. Identifying what activities need to be done each outage for the life of the reactor and bringing the latest technology can make this viable. Tightly planned outages with a small well trained labour force will go a long way to reducing costs. The suite of services and tooling available to the utilities to manage their reactor integrity has improved significantly in recent years and continues to evolve. New feeder inspection technologies can provide improved inspection results for the complex feeder geometry. These improvements lead to more accurate wear rates and better predictions of component life. Feeders that need replacement based on improved inspection techniques can be replaced systematically during regular outages rather than specific refurbishment outages. Targeting areas rather than entire feeders reduces time, dose and cost. In cases where feeder replacement isn't feasible or where unpredicted wear is found, a feeder weld overlay process can be used. To manage the reactor work, new data systems are under development that allow for effective tracking of each activity performed and outcomes in a single package. (author)

Indicators for management of planned outages in nuclear power plants

International Nuclear Information System (INIS)

2006-04-01

The outages considered within the scope of this publication are planned refuelling outages (PWR and BWR nuclear power plants) and planned outages associated with major maintenance, tests and inspections (PHWR and LWGR nuclear power plants). The IAEA has published some valuable reports providing guidance and assistance to operating organizations on outage management. This TECDOC outlines main issues to be considered in outage performance monitoring and provides guidance to operating organizations for the development and implementation of outage programmes which could enhance plant safety, reliability and economics. It also complements the series of reports published by the IAEA on outage management and on previous work related to performance indicators developed for monitoring different areas of plant operation, such as safety, production, reliability and economics. This publication is based upon the information presented at a technical meeting to develop a standardized set of outage indicators for outage optimization, which was organised in Vienna, 6-9 October 2003. At this meeting, case studies and good practices relating to performance indicator utilization in the process of planned outage management were presented and discussed

The control of reactor outages

International Nuclear Information System (INIS)

Bouget, Y.H.; Berteloot, J.M.

1995-01-01

The 1985-1992 period was marked by a continuous decay in French reactors operation. This situation has led the Committee for Outages Mastery to take steps for the improvement of nuclear power plants availability. The control of reactor outages requires an integrated vision of the safety, duration, dosimetry, costs and security aspects and a perfect management of contractors. The paper describes the methodology used for the management and the maintenance of the French PWR reactors stock. A detailed schedule of maintenance tasks with dose estimations is now required from each site to anticipate and optimize the duration of outages. Thanks to this action, a significant reduction of the maintenance costs is observed for the 1992-1995 period. (J.S.). 2 figs

WNP-2 outage safety review methodology

International Nuclear Information System (INIS)

Chiang, Albert; Fu, James

2004-01-01

A practical and versatile method was developed in the flow chart and checklist forms to show the defense-in-depth for various key safety functions of a nuclear power plant during shutdown. Using four different colors (green, yellow, orange, and red) for indication of levels of defense-in-depth is visually impressive, easy to understand, and was adopted by the outage management personnel as a convenient reference tool for maintenance activity planning before the outage, and schedule changes during the outage. This paper describes the method and its application at Washington Public Power Supply System's Nuclear Project 2 (WNP-2). (author)

Unit availability not affected by extending outage cycles

Energy Technology Data Exchange (ETDEWEB)

Smith, D.J.

2003-03-01

To improve their economic dispatch position, more and more plant owners are extending the intervals between major outages for boilers from one year to 18-24 months and for steam turbine up to 12 years. In many instances, extended outage cycles have resulted in no loss in availability or increases in forced outages. The article discusses outage scheduling at Tucson Electric Power's Springville coal-fired plant, the Panther Creek Energy Facility in Pennsylvania, and at Tennessee Valley Authority's coal-fired power plants. 1 fig.

Technology Integration Initiative In Support of Outage Management

Energy Technology Data Exchange (ETDEWEB)

Gregory Weatherby; David Gertman

2012-07-01

Plant outage management is a high priority concern for the nuclear industry from cost and safety perspectives. Often, command and control during outages is maintained in the outage control center where many of the underlying technologies supporting outage control are the same as those used in the 1980’s. This research reports on the use of advanced integrating software technologies and hand held mobile devices as a means by which to reduce cycle time, improve accuracy, and enhance transparency among outage team members. This paper reports on the first phase of research supported by the DOE Light Water Reactor Sustainability (LWRS) Program that is performed in close collaboration with industry to examine the introduction of newly available technology allowing for safe and efficient outage performance. It is thought that this research will result in: improved resource management among various plant stakeholder groups, reduced paper work, and enhanced overall situation awareness for the outage control center management team. A description of field data collection methods, including personnel interview data, success factors, end-user evaluation and integration of hand held devices in achieving an integrated design are also evaluated. Finally, the necessity of obtaining operations cooperation support in field studies and technology evaluation is acknowledged.

Contingency Analysis of Cascading Line Outage Events

Energy Technology Data Exchange (ETDEWEB)

Thomas L Baldwin; Magdy S Tawfik; Miles McQueen

2011-03-01

As the US power systems continue to increase in size and complexity, including the growth of smart grids, larger blackouts due to cascading outages become more likely. Grid congestion is often associated with a cascading collapse leading to a major blackout. Such a collapse is characterized by a self-sustaining sequence of line outages followed by a topology breakup of the network. This paper addresses the implementation and testing of a process for N-k contingency analysis and sequential cascading outage simulation in order to identify potential cascading modes. A modeling approach described in this paper offers a unique capability to identify initiating events that may lead to cascading outages. It predicts the development of cascading events by identifying and visualizing potential cascading tiers. The proposed approach was implemented using a 328-bus simplified SERC power system network. The results of the study indicate that initiating events and possible cascading chains may be identified, ranked and visualized. This approach may be used to improve the reliability of a transmission grid and reduce its vulnerability to cascading outages.

Predicting Power Outages Using Multi-Model Ensemble Forecasts

Science.gov (United States)

Cerrai, D.; Anagnostou, E. N.; Yang, J.; Astitha, M.

2017-12-01

Power outages affect every year millions of people in the United States, affecting the economy and conditioning the everyday life. An Outage Prediction Model (OPM) has been developed at the University of Connecticut for helping utilities to quickly restore outages and to limit their adverse consequences on the population. The OPM, operational since 2015, combines several non-parametric machine learning (ML) models that use historical weather storm simulations and high-resolution weather forecasts, satellite remote sensing data, and infrastructure and land cover data to predict the number and spatial distribution of power outages. A new methodology, developed for improving the outage model performances by combining weather- and soil-related variables using three different weather models (WRF 3.7, WRF 3.8 and RAMS/ICLAMS), will be presented in this study. First, we will present a performance evaluation of each model variable, by comparing historical weather analyses with station data or reanalysis over the entire storm data set. Hence, each variable of the new outage model version is extracted from the best performing weather model for that variable, and sensitivity tests are performed for investigating the most efficient variable combination for outage prediction purposes. Despite that the final variables combination is extracted from different weather models, this ensemble based on multi-weather forcing and multi-statistical model power outage prediction outperforms the currently operational OPM version that is based on a single weather forcing variable (WRF 3.7), because each model component is the closest to the actual atmospheric state.

Analysis of T101 outage radiation dose

International Nuclear Information System (INIS)

Li, Zhonghua

2008-01-01

Full text: Collective radiation dose during outage is about 80% of annual collective radiation dose at nuclear power plants (NPPs). T 101 Outage is the first four-year outage of Unit 1 at Tianwan Nuclear Power Station (TNPS) and thorough overhaul was undergone for the 105-day's duration. Therefore, T 101 Outage has significant reference meaning to reducing collective radiation dose at TNPS. This paper collects the radiation dose statistics during T 101 Outage and analyses the radiation dose distribution according to tasks, work kinds and varying trend of the collective radiation dose etc., comparing with other similar PWRs in the world. Based on the analysis this paper attempts to find out the major factors in collective radiation dose during T 101 Outage. The major positive factor is low radiation level at workplace, which profits from low content of Co in reactor construction materials, optimised high-temperature p H value of the primary circuit coolant within the tight range and reactor operation without trips within the first fuel cycle. One of the most negative factors is long outage duration and many person-hours spent in the radiological controlled zone, caused by too many tasks and inefficient work. So besides keeping good performance of reducing radioactive sources, it should be focused on how to improve implementation of work management including work selection, planning and scheduling, work preparation, work implementation, work assessment and feedback, which can lead to reduced numbers of workers needed to perform a task, of person-hours spent in the radiological controlled zone. Moreover, this leads to reduce occupational exposures in an ALARA fashion. (author)

Immunology of Addison's disease and premature ovarian failure.

Science.gov (United States)

Husebye, Eystein S; Løvås, Kristian

2009-06-01

Autoimmune Addison's disease and autoimmune ovarian insufficiency are caused by selective targeting by T and B lymphocytes to the steroidogenic apparatus in these organs. Autoantibodies toward 21-hydroxylase are a clinically useful marker for autoimmune Addison's disease. Autoantibodies to 21-hydroxylase are found in premature ovarian insufficiency, but others also can be present, notably antibodies against side-chain cleavage enzyme. The autoimmune response primarily targets the theca cells, yielding elevated concentrations of inhibin, which is emerging as a useful diagnostic marker for autoimmune etiology of ovarian insufficiency. Little is known about its immunogenetics, but in contrast to Addison's disease, several experimental models of autoimmune premature ovarian insufficiency are available for study.

Pricing power outages in the Netherlands

Energy Technology Data Exchange (ETDEWEB)

Baarsma, Barbara E.; Hop, J. Peter [SEO Economic Research/University of Amsterdam, Amsterdam (Netherlands)

2009-09-15

In most Western countries, the power grid provides electricity more than 99% of the time. To maintain reliability at such high levels, energy companies have to continually invest in electric transmission- and distribution systems. Since customers of electricity cannot switch from one distribution network to another, no economic incentive exists that matches the supplied reliability to customer preferences. Either under- or over-investment in reliability may thus result. In order to introduce market-like incentives, the Dutch Energy Regulator introduced a regulatory system based on the (perceived) costs of power outages. An essential ingredient of the regulation is the cost of a power outage of a particular duration (i.e., 1 minute). This paper measures these outage cost by using conjoint analysis. We find that the social cost of the present Dutch level of reliability - that is, one outage of two hours every four years - is EUR2.80 on average for every household, and EUR33.10 on average for every SME firm. The total costs to Dutch society are almost EUR50 million. (author)

Residential outage cost estimation: Hong Kong

International Nuclear Information System (INIS)

Woo, C.K.; Ho, T.; Shiu, A.; Cheng, Y.S.; Horowitz, I.; Wang, J.

2014-01-01

Hong Kong has almost perfect electricity reliability, the result of substantial investments ultimately financed by electricity consumers who may be willing to accept lower reliability in exchange for lower bills. But consumers with high outage costs are likely to reject the reliability reduction. Our ordered-logit regression analysis of the responses by 1876 households to a telephone survey conducted in June 2013 indicates that Hong Kong residents exhibit a statistically-significant preference for their existing service reliability and rate. Moreover, the average residential cost estimate for a 1-h outage is US$45 (HK$350), topping the estimates reported in 10 of the 11 studies published in the last 10 years. The policy implication is that absent additional compelling evidence, Hong Kong should not reduce its service reliability. - Highlights: • Use a contingent valuation survey to obtain residential preferences for reliability. • Use an ordered logit analysis to estimate Hong Kong's residential outage costs. • Find high outage cost estimates that imply high reliability requirements. • Conclude that sans new evidence, Hong Kong should not reduce its reliability

Outage management: A case study

International Nuclear Information System (INIS)

Haber, S.B.; Barriere, M.T.; Roberts, K.H.

1992-01-01

Outage management issues identified from a field study conducted at a two-unit commercial pressurized water reactor (PWR), when one unit was in a refueling outage and the other unit was at full power operation, are the focus of this paper. The study was conduced as part of the US Nuclear Regulatory Commission's (NRC) organizational factors research program, and therefore the issues to be addressed are from an organizational perspective. Topics discussed refer to areas identified by the NRC as critical for safety during shutdown operations, including outage planning and control, personnel stress, and improvements in training and procedures. Specifically, issues in communication, management attention, involvement and oversight, administrative processes, organizational culture, and human resources relevant to each of the areas are highlighted by example from field data collection. Insights regarding future guidance in these areas are presented based upon additional data collection subsequent to the original study

Development and demonstration of techniques for reducing occupational radiation doses during refueling outages. Tasks 7A/7B. Advanced outage management and radiation exposure control

International Nuclear Information System (INIS)

1985-03-01

Objectives of Tasks 7A and 7B were to develop and demonstrate computer based systems to assist plant management and staff in utilizing information more effectively to reduce occupational exposures received as a result of refueling outages, and to shorten the duration of the outage. The Advanced Outage Management (AOM) Tool (Task 7A) is an automated outage planning system specifically designed to meet the needs of nuclear plant outage management. The primary objective of the AOM tool is to provide a computerized system that can manipulate the information typically associated with outage planning and scheduling to furnish reports and schedules that more accurately project the future course of the outage. The Radiation Exposure Control (REC) Tool (Task 7B) is a computerized personnel radiation exposure accounting and management system designed to enable nuclear plant management to project and monitor total personnel radiation exposure on a real-time basis. The two systems were designed to operate on the same computer system and interface through a common database that enables information sharing between plant organizations not typically interfaced. This interfacing provides outage planners with a means of incorporating occupational radiation exposure as a factor for making decisions on the course of an outage

A framework and review of customer outage costs: Integration and analysis of electric utility outage cost surveys

Energy Technology Data Exchange (ETDEWEB)

Lawton, Leora; Sullivan, Michael; Van Liere, Kent; Katz, Aaron; Eto, Joseph

2003-11-01

A clear understanding of the monetary value that customers place on reliability and the factors that give rise to higher and lower values is an essential tool in determining investment in the grid. The recent National Transmission Grid Study recognizes the need for this information as one of growing importance for both public and private decision makers. In response, the U.S. Department of Energy has undertaken this study, as a first step toward addressing the current absence of consistent data needed to support better estimates of the economic value of electricity reliability. Twenty-four studies, conducted by eight electric utilities between 1989 and 2002 representing residential and commercial/industrial (small, medium and large) customer groups, were chosen for analysis. The studies cover virtually all of the Southeast, most of the western United States, including California, rural Washington and Oregon, and the Midwest south and east of Chicago. All variables were standardized to a consistent metric and dollar amounts were adjusted to the 2002 CPI. The data were then incorporated into a meta-database in which each outage scenario (e.g., the lost of electric service for one hour on a weekday summer afternoon) is treated as an independent case or record both to permit comparisons between outage characteristics and to increase the statistical power of analysis results. Unadjusted average outage costs and Tobit models that estimate customer damage functions are presented. The customer damage functions express customer outage costs for a given outage scenario and customer class as a function of location, time of day, consumption, and business type. One can use the damage functions to calculate outage costs for specific customer types. For example, using the customer damage functions, the cost experienced by an ''average'' customer resulting from a 1 hour summer afternoon outage is estimated to be approximately $3 for a residential customer, $1

The process of NPP refuelling outage analysis and follow-up

International Nuclear Information System (INIS)

Nemec, T.; Savli, S.; Cernilogar Radez, M.; Persic, A.; Pecek, V.; Stritar, A.

2007-01-01

Following the outages in 2004 and 2006, the Slovenian Nuclear Safety Administration (SNSA) has started with the practice of independent outage analysis in a form of an internal report. It includes a comparison of performed activities against the planned time schedule of activities, evaluation of design modifications implementation and analysis of significant events. The main result of the outage analysis is a list of recommendations and some open issues that have been identified. These findings are the basis for development of an action plan for SNSA activities until the next outage, aimed at eliminating deficiencies found out during the outage and further improving outage activities. The established system of outage supervision together with the final analysis and long term action plan represents an effective continuous safety supervision process, by which the regulatory body independently contributes to the higher level of safety culture both at the licensee and among its own staff. (author)

Extended layup of steam generators during a refurbishment outage

International Nuclear Information System (INIS)

Marks, C.R.; Little, M.D.; Slade, J.; Gendron, T.

2009-01-01

In May 2008, Point Lepreau Generating Station (PLGS), owned and operated by New Brunswick Power Nuclear (NBPN), entered an extended refurbishment outage initially expected to last approximately 18 months. NBPN had the two inter-related goals with respect to layup of the steam generators during this period: equipment preservation and inspection interval modification. The steam generators were to be preserved such that there was no loss of operating life due to corrosion of either the tubing (Alloy 800NG) or other internal components (with carbon steel being the limiting material with respect to corrosion). Additionally, NBPN desired that the time in layup not count as operating time in setting the schedule for future inspections. That is, a key goal of the steam generator layup is that the future inspection interval be based on operating time, not calendar time. The NBPN approach consists of the following four steps: A review of industry operating experience with long outages (including both PWRs and PHWRs); The development of technically based layup strategies and procedures; A mid-outage review of the implementation of the layup strategies and procedures; and A post-outage review to determine if the actual conditions in the steam generators will support modification of the inspection interval. This paper discusses the results of the first three of these steps. At this time, the plant is still in the refurbishment outage. Throughout the outage evaluation process, the following issues have been the main focus of the reviews: The potential for degradation (pitting and cracking) of steam generator tubes; The potential for general corrosion of carbon and low alloy steel internals; Oxidation of deposits (which could subsequently lead to oxidizing conditions during operation, possibly leading to tube degradation). This paper discusses the industry operating experience reviewed, the pre-outage assessments, and the mid-outage assessments. Current outage planning places the

ALARA database value in future outage work planning and dose management

International Nuclear Information System (INIS)

Miller, D.W.; Green, W.H.

1995-01-01

ALARA database encompassing job-specific duration and man-rem plant specific information over three refueling outages represents an invaluable tool for the outage work planner and ALARA engineer. This paper describes dose-management trends emerging based on analysis of three refueling outages at Clinton Power Station. Conclusions reached based on hard data available from a relational database dose-tracking system is a valuable tool for planning of future outage work. The system's ability to identify key problem areas during a refueling outage is improving as more outage comparative data becomes available. Trends over a three outage period are identified in this paper in the categories of number and type of radiation work permits implemented, duration of jobs, projected vs. actual dose rates in work areas, and accuracy of outage person-rem projection. The value of the database in projecting 1 and 5 year station person-rem estimates is discussed

ALARA database value in future outage work planning and dose management

Energy Technology Data Exchange (ETDEWEB)

Miller, D.W.; Green, W.H. [Clinton Power Station Illinois Power Co., IL (United States)

1995-03-01

ALARA database encompassing job-specific duration and man-rem plant specific information over three refueling outages represents an invaluable tool for the outage work planner and ALARA engineer. This paper describes dose-management trends emerging based on analysis of three refueling outages at Clinton Power Station. Conclusions reached based on hard data available from a relational database dose-tracking system is a valuable tool for planning of future outage work. The system`s ability to identify key problem areas during a refueling outage is improving as more outage comparative data becomes available. Trends over a three outage period are identified in this paper in the categories of number and type of radiation work permits implemented, duration of jobs, projected vs. actual dose rates in work areas, and accuracy of outage person-rem projection. The value of the database in projecting 1 and 5 year station person-rem estimates is discussed.

Partnership - its contribution to outage success

International Nuclear Information System (INIS)

Gill, K.S.; Kirton-Darling, F.; Robinson, F.T.

1996-01-01

An innovative approach to developing the teamwork between the power station and the outage contractor has been pioneered over the past three years at the Bradwell nuclear power station in the UK, which houses two Magnox reactors. Magnox Electric and Rolls-Royce Nuclear Engineering Services are now undertaking their third outage under a partnership contract which has provided significant benefits to both parties. (Author)

San Onofre - the evolution of outage management

International Nuclear Information System (INIS)

Slagle, K.A.

1993-01-01

With the addition of units 2 and 3 to San Onofre nuclear station in 1983 and 1984, it became evident that a separate group was needed to manage outages. Despite early establishment of a division to handle outages, it was a difficult journey to make the changes to achieve short outages. Early organizational emphasis was on developing an error-free operating environment and work culture. This is difficult for a relatively large organization at a three-unit site. The work processes and decision styles were designed to be very deliberate with many checks and balances. The organization leadership and accountability were focused in the traditional operations, maintenance, and engineering divisions. Later, our organization emphasis shifted to achieving engineering excellence. With a sound foundation of operating and engineering excellence, our organizational focus has turned to achieving quality outages. This means accomplishing the right work in a shorter duration and having the units run until the next refueling

Human milk for the premature infant

Science.gov (United States)

Underwood, Mark A.

2012-01-01

Synopsis Premature infants are a heterogeneous group with widely differing needs for nutrition and immune protection with risk of growth failure, developmental delays, necrotizing enterocolitis, and late-onset sepsis increasing with decreasing gestational age and birth weight. Human milk from women delivering prematurely has more protein and higher levels of many bioactive molecules compared to milk from women delivering at term. Human milk must be fortified for small premature infants to achieve adequate growth. Mother’s own milk improves growth and neurodevelopment and decreases the risk of necrotizing enterocolitis and late-onset sepsis and should therefore be the primary enteral diet of premature infants. Donor milk is a valuable resource for premature infants whose mothers are unable to provide an adequate supply of milk, but presents significant challenges including the need for pasteurization, nutritional and biochemical deficiencies and a limited supply. PMID:23178065

Outage time reduction in GKN II without loss of safety

International Nuclear Information System (INIS)

Sturm, J.

1999-01-01

GKN II is a 1340 MWE 4-loop pressurised water reactor from Siemens KONVOI type, located in the south of Germany. It was originally connected to the grid at the end of 1988. Commercial operation under utility responsibility started at the second half of 1989. The first outage was performed in 1990. Beginning from this date, the outage duration was contiguously reduced from 33 days to 15 days in 1996. In 1998, two refueling and maintenance outages were performed, each with a duration of 7 days. Key planning factors to achieve these results are: A well adapted planning organisation with an outage manager and an outage planning team. An effective long term planning. This means the combination of work with a long duration every 4 or 8 years. No longlasting work in the years in between. Main work only on one safety train per year. Optimisation and standardisation of the shutdown and the startup sequence. The real change of reactor states have been modified, compared to the vendor recommendations. An tests are assigned to plant conditions, where they are most effective and are less time critical. Small modifications in the plant, mainly on the auxiliary systems, to speedup some sequences. Extreme detailed planning of maintenance and periodic tests. Each work/test can be found in a detailed schedule with a dedicated time widow. Optimized tools to perform the detailed planning and to implement the feedback of experience from former outages. Optimized tools for maintenance and handlings of heavy equipment on the critical path. Optimized tools to perform periodic tests. Key factors during outage are: Permanent control of the schedules with an updated 3-day program. Best and permanent information with this 3-day program of all people that are involved. Fast reaction on delays. Outage managers permanent on site. Gain in safety during shutdown states, with reduced outage duration: It has to be proven, that short outages don't lead to faster and less accurate work. It can be

APPROACH TO ASSESSING THE PREPAREDNESS OF HOSPITALS TO POWER OUTAGES

Directory of Open Access Journals (Sweden)

Lenka BREHOVSKÁ

2017-06-01

Full Text Available Within the secondary impacts of electricity blackouts, it is necessary to pay attention to facilities providing medical care for the population, namely the hospitals. Hospitals represent a key position in the provision of health care also in times of crisis. These facilities must provide constant care; it is therefore essential that the preparedness of such facilities is kept at a high level. The basic aim of this article is to analyse the preparedness of hospitals to power outages (power failures, blackouts within a pilot study. On that basis, a SWOT analysis is used to determine strengths and weaknesses of the system of preparedness of hospitals to power outages and solutions for better security of hospitals are defined. The sample investigated consists of four hospitals founded by the Regional Authority (hospitals Nos. 1-4 and one hospital founded by the Ministry of Health of the Czech Republic (hospital No. 5. The results of the study shows that most weaknesses of the preparedness of hospitals are represented by inadequately addressed reserves of fuel for the main backup power supply, poor knowledge of employees who are insufficiently retrained, and old backup power supplies (even 35 years in some cases.

Partnership - the heart of integrated outage management

International Nuclear Information System (INIS)

Robinson, F.T.

1995-01-01

Changes in the power generating industry continue apace. The effects of privatisation are widely visible: nowhere more so than in the growing national and international competition facing the generators around the world. A successful, long-term marriage between generator and contractor on power station outage management offers significant scope for cost reduction, shortening annual plant downtime and generating more megawatts, all within a safety environment of continuous improvement. Working in close partnership, Nuclear Electric and Rolls-Royce Nuclear Engineering Services have remodelled the whole contractor/client strategy. The new discipline, known as integrated outage management and partnering, is already producing shorter outage periods at Bradwell, a Magnox Station in Essex. (author)

Exploiting Outage and Error Probability of Cooperative Incremental Relaying in Underwater Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Hina Nasir

2016-07-01

Full Text Available This paper embeds a bi-fold contribution for Underwater Wireless Sensor Networks (UWSNs; performance analysis of incremental relaying in terms of outage and error probability, and based on the analysis proposition of two new cooperative routing protocols. Subject to the first contribution, a three step procedure is carried out; a system model is presented, the number of available relays are determined, and based on cooperative incremental retransmission methodology, closed-form expressions for outage and error probability are derived. Subject to the second contribution, Adaptive Cooperation in Energy (ACE efficient depth based routing and Enhanced-ACE (E-ACE are presented. In the proposed model, feedback mechanism indicates success or failure of data transmission. If direct transmission is successful, there is no need for relaying by cooperative relay nodes. In case of failure, all the available relays retransmit the data one by one till the desired signal quality is achieved at destination. Simulation results show that the ACE and E-ACE significantly improves network performance, i.e., throughput, when compared with other incremental relaying protocols like Cooperative Automatic Repeat reQuest (CARQ. E-ACE and ACE achieve 69% and 63% more throughput respectively as compared to CARQ in hard underwater environment.

Cell outage compensation in LTE networks: Algorithms and performance assessment

NARCIS (Netherlands)

Amirijoo, M.; Jorguseski, L.; Litjens, R.; Schmelz, L.C.

2011-01-01

Cell outage compensation is a self-healing function and as such part of the Self-Organising Networks concept for mobile wireless networks. It aims at mitigating the degradation of coverage, capacity and service quality caused by a cell or site level outage. Upon detection of such an outage, cell

Analysis of scrams and forced outages at boiling water reactors

International Nuclear Information System (INIS)

Earle, R.T.; Sullivan, W.P.; Miller, K.R.; Schwegman, W.J.

1980-07-01

This report documents the results of a study of scrams and forced outages at General Electric Boiling Water Reactors (BWRs) operating in the United States. This study was conducted for Sandia Laboratories under a Light Water Reactor Safety Program which it manages for the United States Department of Energy. Operating plant data were used to identify the causes of scrams and forced outages. Causes of scrams and forced outages have been summarized as a function of operating plant and plant age and also ranked according to the number of events per year, outage time per year, and outage time per event. From this ranking, identified potential improvement opportunities were evaluated to determine the associated benefits and impact on plant availability

Maintenance, outages and chemistry really can be compatible

International Nuclear Information System (INIS)

Roberts, J.G.; Deaconescu, R.

2006-01-01

'Full text:' In their address to the Canadian Nuclear Society, Bruce Power's Chemistry Design staff will describe how maintenance and outages can impact negatively on chemistry control and asset protection. Considerations of material impacts and material condition have significant influences on the approach to, and control of, chemistry. This applies equally to operation as it does during unit and/or system outages. Ideas will be presented as to how to facilitate making maintenance, outages and chemistry compatible. It will be shown how the lack of such an approach can lead to disastrous results. (author)

Evaluation of the Planned Outage Durations in EU-APR

Energy Technology Data Exchange (ETDEWEB)

Jung, Byung Joon; Lee, Keun Sung [KHNP CRI, Daejeon (Korea, Republic of)

2016-10-15

EU-APR has been designed to comply with European Utility Requirements (EUR) and nuclear design requirements of the European countries. And it is modified and improved from its original design of APR1400. The whole duration varies depending on items for additional process. Refueling and regular maintenance outage is comprised of basic processes and Main turbine-generator outage includes dismantling inspection of main generator and high pressure turbine as a critical path in addition to basic processes. In-Service Inspection Outage includes Automatic ultrasonic inspection on the upper side/lower side of a nuclear reactor as a critical path in addition to basic processes. The planned outage durations of EU-APR are optimized according to the above results. And they are complied with EUR Requirement (EUR 2.2.7.2.2 B), respectively. In addition, outage duration can be reduced with improved operating technology and more maintenance friendly environment including betterment of filling, drain and ventilation.

Evaluation of the Planned Outage Durations in EU-APR

International Nuclear Information System (INIS)

Jung, Byung Joon; Lee, Keun Sung

2016-01-01

EU-APR has been designed to comply with European Utility Requirements (EUR) and nuclear design requirements of the European countries. And it is modified and improved from its original design of APR1400. The whole duration varies depending on items for additional process. Refueling and regular maintenance outage is comprised of basic processes and Main turbine-generator outage includes dismantling inspection of main generator and high pressure turbine as a critical path in addition to basic processes. In-Service Inspection Outage includes Automatic ultrasonic inspection on the upper side/lower side of a nuclear reactor as a critical path in addition to basic processes. The planned outage durations of EU-APR are optimized according to the above results. And they are complied with EUR Requirement (EUR 2.2.7.2.2 B), respectively. In addition, outage duration can be reduced with improved operating technology and more maintenance friendly environment including betterment of filling, drain and ventilation

Improving refueling outages through partnership

International Nuclear Information System (INIS)

Mercado, Angelo L.

2004-01-01

This paper describes an approach to reduce nuclear plant outage duration and cost through partnership. Partnership is defined as a long-term commitment between the utility and the vendor with the objective of achieving shared business goals by maximizing the effectiveness of each party's resources. The elements of an effective partnership are described. Specific examples are given as to how partnership has worked in the effective performance of refueling outages. To gain the full benefits of a partnership, both parties must agree to share information, define the scope early, communicate goals and expectations, and identify boundaries for technical ownership. (author)

Outages planning; Planificacion de recargas

Energy Technology Data Exchange (ETDEWEB)

Blanquer, N.

2010-07-01

The reason of a nuclear power plant outage seems easy. Replace 1/3 of the total core fuel inside reactor for a new, store the old one in a pool and shuffle the rest 2/3 in other positions in the core to optimize fuel burn up. Also is needed to make the preventive, corrective and conservative maintenance, the selected design changes and the regulatory and technical requirements for equipment and systems. To make the plant outage strategy for all the above pack with nuclear safety not challenged is the objective of this article for the Spanish Nuclear Society magazine. (Author)

Outage management

International Nuclear Information System (INIS)

Anonymous

2006-01-01

Since constructing Japan's first PWR plant, Mihama Unit 1, MHI has been working to upgrade its technologies. The ongoing goal is to provide PWR nuclear power plants with levels of reliability, safety, economy operation and maintainability unparalleled in the world market. To fulfill its obligations and responsibility as an integrated plant manufacturer in the nuclear industry, MHI keeps a close eye on every facility, component, device and sub-component from the viewpoint of its customers. Backed by its rich experience and advanced technology, MHI continues to enhance the safety, reliability and economy of nuclear plants introducing improvements at every level. MHI continues to develop and improve diagnostic and inspection technologies based on its more than 30 years of experience in inspection and servicing the major and auxiliary facilities within nuclear power plants. MHI secures the integrity of components by developing and deploying technologies to minimize the wear of components and to repair and replace parts either degraded by age or unduly susceptible to wear. MHI backs its development of these technologies with its comprehensive technical capabilities in the design of remote operation equipment and electro mechanics as well as its expertise in basic technologies such as welding and machining. Mitsubishi Heavy Industries, Ltd. is not only a PWR plant constructor, but also offers complete outage support and component services. In partnership with our customers, MHI is helping to reduce outage duration, radiation exposure and costs, by providing its state of the art engineering knowledge, advanced non-destructive examination, inspection, maintenance and repair technologies mentioned above. MHI is performing large equipment refurbishment such as Steam Generator Replacement, Reactor Vessel Head Replacement, LP/HP turbine replacement, and recently completed the first Core Internal Replacement in the world. The following activities are part of the outage

Premature failure analysis of forged cold back-up roll in a continuous tandem mill

International Nuclear Information System (INIS)

Rad, Hamid Reza Bakhsheshi; Monshi, Ahmad; Idris, Mohd Hasbullah; Kadir, Mohammed Rafiq Abdul; Jafari, Hassan

2011-01-01

Highlights: → Metal wrapping and strip welding in work/back-up rolls contact zone caused spalling. → MnS inclusion and pore initiated crack which propagated in milling led to spalling. → Retained austenite conversion to α'-martensite accelerated spalling failure. → Needle shaped carbide (Fe,Mo,Cr) 7 C 3 , may cause poor service life of back-up roll. -- Abstract: In this paper, premature failure of a forged back-up roll from a continuous tandem mill was investigated. Microstructural evolutions of the spalled specimen and surface of the roll were characterized by optical microscopy, X-ray diffraction, scanning electron microscopy and ferritscopy, while hardness value of the specimen was measured by Vickers hardness testing. The results revealed that the presence of pore and MnS inclusion with spherical and oval morphologies were the main contributing factors responsible for the poor life of the back-up roll. In addition, metal pick up and subsequently strip welding on the surface of the work roll were found as the major causes of failure in work roll which led to spalling occurrence in the back-up roll. Furthermore, relatively high percentage of retained austenite, say 9%, in outer surface of the back-up roll contributed spalling due to conversion of this meta-stable phase to martensite and creation of volume expansion on the outer surface through work hardening during mill campaign.

Maintenance, outages and chemistry really can be compatible

Energy Technology Data Exchange (ETDEWEB)

Roberts, J.G.; Deaconescu, R. [Bruce Power, Tiverton, Ontario (Canada)

2006-07-01

'Full text:' In their address to the Canadian Nuclear Society, Bruce Power's Chemistry Design staff will describe how maintenance and outages can impact negatively on chemistry control and asset protection. Considerations of material impacts and material condition have significant influences on the approach to, and control of, chemistry. This applies equally to operation as it does during unit and/or system outages. Ideas will be presented as to how to facilitate making maintenance, outages and chemistry compatible. It will be shown how the lack of such an approach can lead to disastrous results. (author)

Investigating the role of X chromosome breakpoints in premature ovarian failure

Directory of Open Access Journals (Sweden)

Baronchelli Simona

2012-07-01

Full Text Available Abstract The importance of the genetic factor in the aetiology of premature ovarian failure (POF is emphasized by the high percentage of familial cases and X chromosome abnormalities account for 10% of chromosomal aberrations. In this study, we report the detailed analysis of 4 chromosomal abnormalities involving the X chromosome and associated with POF that were detected during a screening of 269 affected women. Conventional and molecular cytogenetics were valuable tools for locating the breakpoint regions and thus the following karyotypes were defined: 46,X,der(Xt(X;19(p21.1;q13.42mat, 46,X,t(X;2(q21.33;q14.3dn, 46,X,der(Xt(X;Y(q26.2;q11.223mat and 46,X,t(X;13(q13.3;q31dn. A bioinformatic analysis of the breakpoint regions identified putative candidate genes for ovarian failure near the breakpoint regions on the X chromosome or on autosomes that were involved in the translocation event. HS6ST1, HS6ST2 and MATER genes were identified and their functions and a literature review revealed an interesting connection to the POF phenotype. Moreover, the 19q13.32 locus is associated with the age of onset of the natural menopause. These results support the position effect of the breakpoint on flanking genes, and cytogenetic techniques, in combination with bioinformatic analysis, may help to improve what is known about this puzzling disorder and its diagnostic potential.

Approach to shortening duration of nuclear plant refueling outage

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Yoshiharu; Nakanishi, Tooru [Mitsubishi Heavy Industries Ltd., Kobe (Japan). Kobe Shipyard and Machinery Works; Yoshihara, Seiichi; Kanbara, Masayuki; Yamanaka, Misao; Shimizu, Takeshi

1998-07-01

This paper summarizes the mission role of the MHI in-house project team for a shorter outage duration for PWR plants operating in Japan and its results. The major tasks of project team are benchmarking to develop outage performance goals, and develop recommendation packages for outage enhancement covering field procedures and tooling betterment. An optimization study for maintenance tasks was also carried out. This paper highlights the results of efforts the activities of the project team. (author)

Elimination of maintenance outage and cost reduction by development of outage-free maintenance techniques

International Nuclear Information System (INIS)

Jakabe, Hideo; Maruyama, Yoshinaga

1996-01-01

The development program of KEPCO on outage-free maintenance techniques for distribution line work since 1984 is overviewed. It has succeeded in eliminating maintenance outages since 1989. The original aim was to improve customer satisfaction. However, in all, four benefits were realised through the development. These are cost reduction, securing of worker safety, improvement of customer service, and advancement of distribution techniques and morale in KEPCO. The introduction of robotic techniques for maintenance work and manipulator techniques for repair work is planned for further modernization. These new techniques are helping in both work safety and work efficiency improvement. Cost reduction and advancement of distribution line work techniques is also considered. (R.P.)

On Outage Performance of Spectrum-Sharing Communication over M-Block Fading

KAUST Repository

Alabbasi, AbdulRahman

2015-12-06

In this paper, we consider a cognitive radio system in which a block-fading channel is assumed. Each transmission frame consists of M blocks and each block undergoes a different channel gain. Instantaneous channel state information about the interference links remains unknown to the primary and secondary users. We minimize the secondary user\\'s targeted outage probability over the block-fading channels. To protect the primary user, a statistical constraint on its targeted outage probability is enforced. The secondary user\\'s targeted outage region and the corresponding optimal power are derived. We also propose two sub-optimal power strategies and derive compact expressions for the corresponding outage probabilities. These probabilities are shown to be asymptotic lower and upper bounds on the outage probability. Utilizing these bounds, we derive the exact diversity order of the secondary user outage probability. Selected numerical results are presented to characterize the system\\'s behavior.

Radiation-induced premature menopause: a misconception

International Nuclear Information System (INIS)

Madsen, Berit L.; Giudice, Linda; Donaldson, Sarah S.

1995-01-01

Purpose: To disprove the common view that women who have undergone irradiation to fields excluding the pelvis are at risk for radiation-induced premature menopause, we reviewed menstrual function and fertility among women treated with subtotal lymphoid irradiation for Hodgkin's Disease. Methods and Materials: Treatment and follow-up records of all women less than age 50 at the time of diagnosis of Stage I or II supradiaphragmatic Hodgkin's Disease, treated with subtotal lymphoid irradiation alone and enrolled in radiotherapy trials from 1967 to 1985, were reviewed. In addition, patients were surveyed regarding their menstrual status and fertility history. Results: Thirty-six women, aged 10 to 40 years, with normal menstrual function at the time of Hodgkin's diagnosis, were identified. Mean follow-up was 14 years, with a range of 1.25-22.75 years. The average radiation dose to mantle and paraaortic fields was 40-44 Gy; the calculated scatter radiation dose to the pelvis at the ovaries was 3.2 Gy. There were 38 pregnancies in 18 women; all offspring are normal. One of 36 women (2.7%) experienced premature menopause. The reported rate of premature menopause in women who have not undergone irradiation is 1-3%; not significantly different than the rate in our study. There is a syndrome whereby antibodies to several endocrine organs occur (including the ovary), which is associated with premature ovarian failure. This syndrome may be associated with prior radiation to the thyroid, such as that given by mantle-irradiation for Hodgkin's Disease. We report such a case. Conclusion: There is little risk of premature menopause in women treated with radiation fields that exclude the pelvis. Women with presumed radiation-induced premature menopause warrant an evaluation to exclude other causes of ovarian failure, such as autoimmune disorders

Reactor outage schedule (tentative)

Energy Technology Data Exchange (ETDEWEB)

Walton, R.P.

1969-11-01

This single page document is the November 1, 1969 reactor refueling outage schedule for the Hanford Production Reactor. It also contains data on the amounts and types of fuels to be loaded and relocated in the production reactor.

Reactor outage schedule (tentative)

Energy Technology Data Exchange (ETDEWEB)

Walton, R.P.

1969-10-01

This single page document is the October 1, 1969 reactor refueling outage schedule for the Hanford Production Reactor. It also contains data on the amounts and types of fuels to be loaded and relocated in the Production Reactor.

Reactor outage schedule (tentative)

Energy Technology Data Exchange (ETDEWEB)

Walton, R.P.

1969-10-15

This single page document is the October 15, 1969 reactor refueling outage schedule for the Hanford Production Reactor. It also contains data on the amounts and types of fuels to be loaded and relocated in the Production Reactor.

Reactor outage schedule (tentative)

Energy Technology Data Exchange (ETDEWEB)

Walton, R.P.

1969-09-15

This single page document is the September 15, 1969 reactor refueling outage schedule for the Hanford Production Reactor. It also contains data on the amounts and types of fuels to be loaded and relocated in the Production Reactor.

Reactor outage schedule (tentative)

Energy Technology Data Exchange (ETDEWEB)

Walton, R.P.

1969-12-15

This single page document is the December 16, 1969 reactor refueling outage schedule for the Hanford Production Reactor. It also contains data on the amounts and types of fuels to be loaded and relocated in the Production reactor.

Reactor outage schedule (tentative)

Energy Technology Data Exchange (ETDEWEB)

Walton, R.P.

1969-12-01

This single page document is the December 1, 1969 reactor refueling outage schedule for the Hanford Production Reactor. It also contains data on the amounts and types of fuels to be loaded and relocated in the Production reactor.

Integrated use of Primavera and ORAM codes in outage 1999 at NPP Krsko

International Nuclear Information System (INIS)

Krajnc, J.; Skaler, F.; Basic, I.; Kocnar, R.

1999-01-01

The paper deals with the following postulated main goals of outage scheduling with Primavera tool at Krsko NPP: planning and controlling of resources (people, equipment, locations, sources), controlling the safety aspects of an outage and assuring defense-in-depth philosophy (through integrated safety assessment by ORAM code), diversity use of the plan during preparations period and outage progress (MCB, work leaders, management, planning Dept., subcontractors, support, etc.), allowing for optimization of outage duration. A snapshot in Primavera of what actually happened in outage 1999, lessons learned and a new work template is the scope of the next year outage.(author)

Line outage contingency analysis including the system islanding scenario

Energy Technology Data Exchange (ETDEWEB)

Hazarika, D.; Bhuyan, S. [Assam Engineering College, Jalukbari, Guwahati 781013 (India); Chowdhury, S.P. [Jadavpur University, Jadavpur, Kolkata 700 032 (India)

2006-05-15

The paper describes an algorithm for determining the line outage contingency of a line taking into account of line over load effect in remaining lines and subsequent tripping of over loaded line(s) leading to possible system split or islanding of a power system. The optimally ordered sparse [B'], [B'] matrices for the integrated system are used for load flow analysis to determine modified values of voltage phase angles [{delta}] and bus voltages [V] to determine the over loading effect on the remaining lines due to outage of a selected line outage contingency. In case of over loading in remaining line(s), the over loaded lines are removed from the system and a topology processor is used to find the islands. A fast decoupled load flow (FDLF) analysis is carried out for finding out the system variables for the islanded (or single island) system by incorporating appropriate modification in the [B'] and [B'] matrices of the integrated system. Line outage indices based on line overload, loss of load, loss of generation and static voltage stability are computed to indicate severity of a line outage of a selected line. (author)

Good practices for outage management in nuclear power plants

International Nuclear Information System (INIS)

1991-09-01

As a follow-up to an earlier Technical Document on Good Practices for Improved Nuclear Power Plant Performance (IAEA-TECDOC-498), the Agency has produced a more focused technical report on good practices associated with nuclear power plant outage planning and execution. As with the earlier document, the overall aim is that by identifying good practices in the key aspects of outage management, overall world nuclear performance will improve and the gap between excellent performers and operators with developing programmes will be narrowed. This document has been produced through the contribution of numerous operators and government agencies. It aims at minimizing text and focusing on actual good practices in use which can be found in the annexes. While the specific methods used to achieve excellence in maintenance/refuelling outages may differ, the fundamental requirements of outage management are discussed

Premature ovarian failure (POF in Brazilian fragile X carriers

Directory of Open Access Journals (Sweden)

Angela M. Vianna-Morgante

1999-12-01

Full Text Available The gynecological and reproductive histories of 193 women from fragile X families were surveyed. Among the 101 carriers of the premutation, 14 experienced premature menopause, contrarily to their 37 fully mutated and 55 noncarrier female relatives. Although premature menopause showed a tendency to cluster in certain fragile X families, as a group, the premutated women experienced menopause earlier than noncarriers. This suggests that premature menopause may be the extreme effect of a spectrum of ovarian anomalies associated with the fragile X premutation.Entrevistamos 193 mulheres de famílias com afetados pela síndrome do cromossomo X frágil, quanto a sua história ginecológica e reprodutiva. Entre as 101 portadoras da pré-mutação, 14 tiveram menopausa precoce, mas nenhuma das 37 portadoras da mutação completa ou das 55 não portadoras apresentaram esta anomalia. Observamos uma tendência para a concentração da menopausa precoce em certas famílias, o que poderia significar uma peculiariedade de certas pré-mutações. Entretanto, o fato de as mulheres pré-mutadas tenderem a entrar em menopausa mais cedo do que as não portadoras sugere que a menopausa precoce seja o extremo do espectro de efeitos ovarianos da pré-mutação.

[Responding to patients with home mechanical ventilation after the Great East Japan Earthquake and during the planned power outages. How should we be prepared for a future disaster ?].

Science.gov (United States)

Takechi, Yukako

2011-12-01

The unprecedented earthquake(magnitude-9 in the Japanese seismic intensity scale)hit off the east coast of Japan on March 11, 2011. Consequently, there were planned power outages in the area nearby Tokyo to avoid massive blackouts caused by a stoppage of Fukushima nuclear plants.Our clinic located in Kawasaki city was also hit by the earthquake(magnitude- 5).During the period of two months(March and April 2011), we had a total of 52 patients with home respiratory care (5-TPPV, 11-NPPV and 36-HOT)at that time.Two out of three 24 hour-TPPV users had no external battery.After the earthquake, there was a 7-hour electricity failure in some areas, and a patient with ASV(adaptive servo ventilator)was living there.Moreover, 3-hour/day power outages were carried out from March 14 to March 28, affecting people's everyday lives. However, the patient had no harmful influences from the power failure because a ventilation company lent us an external battery(4-9 hour life capacity)for the patients, and we were able to avoid an emergency situation caused by the power failure.In conclusion, we ought to be prepared for patients with home mechanical ventilation in the future toward unforeseen large scale power outages.

Saving doses by outage planning strategy and architectural arrangements

International Nuclear Information System (INIS)

Wahlstroem, B.

1993-01-01

All radiation doses come out as a result of dose rate and exposure time, and the main part of the occupational exposure is caused during outages. While every reasonable attempt should be made to lower the dose rates, the other factor, the exposure time, may not be forgotten. The paper presents possible ways of saving man-hours in the controlled zone by outage planning strategy. And every saved man-hour means a saved radiation dose. At Loviisa NPS also some special architectural arrangements contribute to shortening the outage time, thus saving doses

Outage performance of cognitive radio systems with Improper Gaussian signaling

KAUST Repository

Amin, Osama

2015-06-14

Improper Gaussian signaling has proved its ability to improve the achievable rate of the systems that suffer from interference compared with proper Gaussian signaling. In this paper, we first study impact of improper Gaussian signaling on the performance of the cognitive radio system by analyzing the outage probability of both the primary user (PU) and the secondary user (SU). We derive exact expression of the SU outage probability and upper and lower bounds for the PU outage probability. Then, we design the SU signal by adjusting its transmitted power and the circularity coefficient to minimize the SU outage probability while maintaining a certain PU quality-of-service. Finally, we evaluate the proposed bounds and adaptive algorithms by numerical results.

Long-term optimization of outage performance

International Nuclear Information System (INIS)

Huemmeler, Alexander; Jakobs, Norbert; Seifert, Siegfried

2003-01-01

Deregulation of the power markets and the accompanying pressure on electricity prices have forced all electric utilities to reduce their power generating costs in order to be able to hold their own in the new market environment. This has also particularly affected the operators of nuclear power plants since they have to compete against the lower power generating costs of fossil-fired combined-cycle power plants and, in Germany are faced with a difficult political climate. The areas identified as having the greatest cost-cutting potential were fuel costs, operating costs and measures to increase plant availability. The main objective behind increasing plant availability was not only to improve the already high standard of operational reliability and plant safety even further, but also to significantly shorten the downtime needed for annual refueling outages. A variety of measures aimed at shortening scheduled plant outages have thus been developed and successfully implemented by nuclear plant operators. At the same time, process improvements and new technologies have been introduced by the service providers. Both initiatives together have contributed towards substantially reducing outage time and cost. (author)

Line outage contingency analysis including the system islanding ...

African Journals Online (AJOL)

The optimally ordered sparse [Bʹ], [Bʺ] matrices for the integrated system are used for load flow analysis to determine modified values of voltage phase angles [d] and bus voltages [V] to determine the over loading effect on the remaining lines due to outage of a selected line outage contingency. In case of over loading in ...

Use of collaboration software to improve nuclear power plant outage management

Energy Technology Data Exchange (ETDEWEB)

Germain, Shawn

2015-02-01

Nuclear Power Plant (NPP) refueling outages create some of the most challenging activities the utilities face in both tracking and coordinating thousands of activities in a short period of time. Other challenges, including nuclear safety concerns arising from atypical system configurations and resource allocation issues, can create delays and schedule overruns, driving up outage costs. Today the majority of the outage communication is done using processes that do not take advantage of advances in modern technologies that enable enhanced communication, collaboration and information sharing. Some of the common practices include: runners that deliver paper-based requests for approval, radios, telephones, desktop computers, daily schedule printouts, and static whiteboards that are used to display information. Many gains have been made to reduce the challenges facing outage coordinators; however; new opportunities can be realized by utilizing modern technological advancements in communication and information tools that can enhance the collective situational awareness of plant personnel leading to improved decision-making. Ongoing research as part of the Light Water Reactor Sustainability Program (LWRS) has been targeting NPP outage improvement. As part of this research, various applications of collaborative software have been demonstrated through pilot project utility partnerships. Collaboration software can be utilized as part of the larger concept of Computer-Supported Cooperative Work (CSCW). Collaborative software can be used for emergent issue resolution, Outage Control Center (OCC) displays, and schedule monitoring. Use of collaboration software enables outage staff and subject matter experts (SMEs) to view and update critical outage information from any location on site or off.

Assessing energy supply security: Outage costs in private households

International Nuclear Information System (INIS)

Praktiknjo, Aaron J.; Hähnel, Alexander; Erdmann, Georg

2011-01-01

The objective of this paper is to contribute to the topic of energy supply security by proposing a Monte Carlo-based and a survey based model to analyze the costs of power interruptions. Outage cost estimations are particularly important when deciding on investments to improve supply security (e.g. additional transmission lines) in order to compare costs to benefits. But also other policy decisions on measures that have direct or indirect consequences for the supply security (e.g. a phasing out of nuclear energy) need to be based on results from outage cost estimations. The main focus of this paper lies with residential consumers, but the model is applied to commercial, industrial and governmental consumers as well. There are limited studies that have approached the problem of evaluating outage cost. When comparing the results of these studies, they often display a high degree of diversification. As consumers have different needs and dependencies towards the supply of electricity because of varying circumstances and preferences, a great diversity in outage cost is a logical consequence. To take the high degree of uncertainties into account, a Monte Carlo simulation was conducted in this study for the case of private households in Germany. - Highlights: ► A macroeconomic model to assess outage cost is proposed. ► Possibilities for substitution are considered by analyzing individual preferences for the time-use. ► Uncertainties are taken into account by using a Monte Carlo simulation. ► This study reveals the distribution of outage costs to different electricity consumers. ► Implications for energy policy decisions are discussed.

Balance-of-plant outage availability study. Phase I. Extension report

International Nuclear Information System (INIS)

Thomasson, F.R.

1978-09-01

After completion of the Phase 1 Refueling Outage Availability Study, Babcock and Wilcox and the U.S. Department of Energy entered into a supplemental agreement to perform a balance-of-plant maintenance, inspection, and test study with the cooperation of Duke Power Company and Arkansas Power and Light Company. The objectives were (1) to expand the Phase 1 data base, including balance-of-plant activities, to reduce outage time and increase plant availability and (2) to conduct an onsite review of plant maintenance, practices to complement the utility efforts in reducing outage time and increasing on-line operational time. Data were obtained from (1) observations during the 1977 refueling outage at Oconee 3, (2) review of maintenance practices during the Arkansas Nuclear One, Unit 1, operational cycle in 1977, and (3) selected observations of the 1978 refueling outage at ANO-1. Accumulated data were then reviewed and analyzed to produce a list of improvement recommendations for Oconee 3 and ANO-1 that can be generically applied to plants of similar design and construction

Underlay Cognitive Radio Systems with Improper Gaussian Signaling: Outage Performance Analysis

KAUST Repository

Amin, Osama

2016-03-29

Improper Gaussian signaling has the ability over proper (conventional) Gaussian signaling to improve the achievable rate of systems that suffer from interference. In this paper, we study the impact of using improper Gaussian signaling on the performance limits of the underlay cognitive radio system by analyzing the achievable outage probability of both the primary user (PU) and secondary user (SU). We derive the exact outage probability expression of the SU and construct upper and lower bounds of the PU outage probability which results in formulating an approximate expression of the PU outage probability. This allows us to design the SU signal by adjusting its transmitted power and the circularity coefficient to minimize the SU outage probability while maintaining a certain PU quality-of-service. Finally, we evaluate the derived expressions for both the SU and the PU and the corresponding adaptive algorithms by numerical results.

Underlay Cognitive Radio Systems with Improper Gaussian Signaling: Outage Performance Analysis

KAUST Repository

Amin, Osama; Abediseid, Walid; Alouini, Mohamed-Slim

2016-01-01

Improper Gaussian signaling has the ability over proper (conventional) Gaussian signaling to improve the achievable rate of systems that suffer from interference. In this paper, we study the impact of using improper Gaussian signaling on the performance limits of the underlay cognitive radio system by analyzing the achievable outage probability of both the primary user (PU) and secondary user (SU). We derive the exact outage probability expression of the SU and construct upper and lower bounds of the PU outage probability which results in formulating an approximate expression of the PU outage probability. This allows us to design the SU signal by adjusting its transmitted power and the circularity coefficient to minimize the SU outage probability while maintaining a certain PU quality-of-service. Finally, we evaluate the derived expressions for both the SU and the PU and the corresponding adaptive algorithms by numerical results.

Planning and management of outages in nuclear power plants

International Nuclear Information System (INIS)

Sica, G.F.; Fusari, W.; Reginelli, A.

1984-01-01

At present the Ente Nazionale per l'Energia Elettrica (ENEL) operates three nuclear power plants, only one of which belongs to the new generation, i.e. the Caorso Nuclear Power Plant which has been in commercial operation since December 1981. Outage planning, implementation and analysis are very important in order to minimize the shutdown time and thus improve plant availability, which is of particular importance for a large nuclear power plant. Such activities are very complicated because of the large number of jobs that have to be performed in accordance with detailed written procedures and which have to be properly documented and controlled. Large off-site resources are required which have to be accurately interfaced with on-site staff. The ENEL is making a great effort to define both the administrative and technical aspects of refuelling outages. As outage planning requires the availability and handling of a large amount of data and information, a maintenance information system that has been widely used in conventional plants was applied, with some modifications made especially for the Caorso Nuclear Power Plant. After two years the following results have been achieved: a large number of raw and processed data are now available, the first refuelling outage was carried out with few problems and according to schedule, and the second refuelling outage, based on the experience of the first, required somewhat less preparation and is developing well even though many special activities have had to be scheduled. The ENEL believes that the efforts made in the planning and management areas will pay off in terms of the short duration, smoothness and economy of further outages, both for Caorso and for future plants. (author)

Estimating Power Outage Cost based on a Survey for Industrial Customers

Science.gov (United States)

Yoshida, Yoshikuni; Matsuhashi, Ryuji

A survey was conducted on power outage cost for industrial customers. 5139 factories, which are designated energy management factories in Japan, answered their power consumption and the loss of production value due to the power outage in an hour in summer weekday. The median of unit cost of power outage of whole sectors is estimated as 672 yen/kWh. The sector of services for amusement and hobbies and the sector of manufacture of information and communication electronics equipment relatively have higher unit cost of power outage. Direct damage cost from power outage in whole sectors reaches 77 billion yen. Then utilizing input-output analysis, we estimated indirect damage cost that is caused by the repercussion of production halt. Indirect damage cost in whole sectors reaches 91 billion yen. The sector of wholesale and retail trade has the largest direct damage cost. The sector of manufacture of transportation equipment has the largest indirect damage cost.

Reliabilty worth: Development of a relationship with outage magnitude, duration and frequency

International Nuclear Information System (INIS)

Turner, F.P.P.; Katrichak, A.M.; Dwyer, A.; Edwards, D.; Ibrahim, A.

1994-01-01

British Columbia Hydro's Worth Project Team was founded to determine values for reliability for reference in evaluation of investment and operating decisions. Work to date has produced key preliminary values for specific outages and concepts for the shape of the relationship between value and these determinates of reliability worth, frequency, magnitude and duration. These values and concepts are described. The values are developed through an iterative, trial and refinement approach. The approach incorporates direct input from customers, common sense and judgement, and micro- and macro-economic concepts. Reliability worth values for reduced or prevented outages are presented for residential, commercial, small industrial and mixed sectors and various outage durations. Reliability worth values were obtained through customer surveys. Limitations of the reliability worth value are numerous and are listed. Study of cost vs magnitude of interruption using microeconomic models has shown that costly system improvements to reduce the possibility of widespread outages may not be justified. The case of exceptionally large area outages (blackouts) is examined. The cost vs frequency relationship was examined in terms of the economic concept of utility or satisfaction. Different loss/frequency characteristics are demonstrated for different customer classes. Customer value for reduced outage duration is expressed in a curve with flatter slope than that for eliminated outages. 2 refs., 6 figs

The Role of Occupational Health and Safety in Complex Outage Services to NPPs

International Nuclear Information System (INIS)

Rozman, A.; Androjna, A.

2010-01-01

Meeting outage schedules in NPPs which are increasingly demanding, apart from all other aspects, introduces a new perspective on occupational health and safety (OHS). Not only is the OHS a constituent part of a plant's overall outage management, it above all dictates paramount objectives to outage service providers. The paper reviews the impacts of reductions of outage durations on OHS and presents related experience of the leading Slovenian outage services provider, NUMIP d.o.o. over the last ten years. The company is now getting prepared for its 12th outage at Krsko NPP in 2010, and has not have recorded a major injury so far, even though these projects engaged over 450 people at a time on-site. To achieve such results, a lot of emphasis is being put onto OHS management prior to and during outages. A certified OHSAS 18001 system has been established and implemented to further support preparation and execution of NUMIP's outage activities at Krsko NPP, and also for other projects. An effective continuous improvement system is built into the project, providing for implementation of lessons learned from domestic and foreign plants. To illustrate the topic in more detail, a case on a Seismic protection of polar crane project is presented. It took place in the 2009 Outage and has certainly been one of the most demanding projects from the OHS point of view for NUMIP so far. The paper aims at contributing to a better understanding of the role of effective management of OHS on the side of a service provider, and, consequently, in the overall outage success of a plant.(author).

Outage Risk Assessment and Management (ORAM) thermal-hydraulics toolkit

International Nuclear Information System (INIS)

Denny, V.E.; Wassel, A.T.; Issacci, F.; Pal Kalra, S.

2004-01-01

A PC-based thermal-hydraulic toolkit for use in support of outage optimization, management and risk assessment has been developed. This mechanistic toolkit incorporates simple models of key thermal-hydraulic processes which occur during an outage, such as recovery from or mitigation of outage upsets; this includes heat-up of water pools following loss of shutdown cooling, inadvertent drain down of the RCS, boiloff of coolant inventory, heatup of the uncovered core, and reflux cooling. This paper provides a list of key toolkit elements, briefly describes the technical basis and presents illustrative results for RCS transient behavior during reflux cooling, peak clad temperatures for an uncovered core and RCS response to loss of shutdown cooling. (author)

Activities of maintenance and outage

International Nuclear Information System (INIS)

Gracia-Orellan, J. M.; Gonzalez, P. L.; Verdu, M. F.; Fernandez, J. A.

2004-01-01

Iberinco Nuclear Generation Department have wanted to promote service activities in nuclear power plants for years besides its dedication to engineering activities. for it, in 1997 Nuclear Services Management was created to complement engineering activities and to be able to make an offer for products and turn key services. People involved in this Management have an extensive experience in Services Area, so that all type of maintenance works are promoted, as well other services like dismantling, fallout management and new equipment's for nuclear power plants services. Iberinco's experience in Support Services in Nuclear Power Plants allows to answer effectively to special workers during operation cycle and outages periods. These activities have been made in spanish nuclear power plants and Angra I and II plants, both of them in Brazil. In this area we provide Technical Consulting Management and Supervision to develop the following activities: - Improvement Maintenance Programs based in PSA: Implantation of Maintenance Rule in the plants. - Supervision and Assembly of design modifications in structures, systems and components. - Fulfilment of efficiency tests, inspection and turbo-group modification. - Noise and vibrations analysis. - Valves and rotative equipment calculations and diagnosis tests. Iberinco develop these outage activities itself or as contractors coordinator under its management. A lot of them have been working with Iberinco for many years and have a great experience in the Service Area they are developing. In this article, the main outage activities developed for Iberinco are detailed. (Author)

Randomized controlled trial comparing nasal intermittent positive pressure ventilation and nasal continuous positive airway pressure in premature infants after tracheal extubation

Directory of Open Access Journals (Sweden)

Daniela Franco Rizzo Komatsu

Full Text Available Summary Objective: To analyze the frequency of extubation failure in premature infants using conventional mechanical ventilation (MV after extubation in groups subjected to nasal intermittent positive pressure ventilation (nIPPV and continuous positive airway pressure (nCPAP. Method: Seventy-two premature infants with respiratory failure were studied, with a gestational age (GA ≤ 36 weeks and birth weight (BW > 750 g, who required tracheal intubation and mechanical ventilation. The study was controlled and randomized in order to ensure that the members of the groups used in the research were chosen at random. Randomization was performed at the time of extubation using sealed envelopes. Extubation failure was defined as the need for re-intubation and mechanical ventilation during the first 72 hours after extubation. Results: Among the 36 premature infants randomized to nIPPV, six (16.6% presented extubation failure in comparison to 11 (30.5% of the 36 premature infants randomized to nCPAP. There was no statistical difference between the two study groups regarding BW, GA, classification of the premature infant, and MV time. The main cause of extubation failure was the occurrence of apnea. Gastrointestinal and neurological complications did not occur in the premature infants participating in the study. Conclusion: We found that, despite the extubation failure of the group of premature infants submitted to nIPPV being numerically smaller than in premature infants submitted to nCPAP, there was no statistically significant difference between the two modes of ventilatory support after extubation.

Failures on stainless steel components

International Nuclear Information System (INIS)

Haenninen, H.

1994-01-01

Economic losses due to failure mainly by corrosion in process and nuclear industries are considered. In these industries the characteristics of different forms of corrosion and their economic effects are fairly well known and, especially, in nuclear industry the assessment of corrosion related costs has been comprehensive. In both industries the economic losses resulting from environmentally enhanced cracking of stainless steel components and the accompanying failures and outages have been considerable, owing as much to the frequency as the unpredictability of such occurrences. (orig.)

Balance-of-plant outage availability study. Phase I. Extension report. [PWR

Energy Technology Data Exchange (ETDEWEB)

Thomasson, F.R.

1978-09-01

After completion of the Phase 1 Refueling Outage Availability Study, Babcock and Wilcox and the U.S. Department of Energy entered into a supplemental agreement to perform a balance-of-plant maintenance, inspection, and test study with the cooperation of Duke Power Company and Arkansas Power and Light Company. The objectives were (1) to expand the Phase 1 data base, including balance-of-plant activities, to reduce outage time and increase plant availability and (2) to conduct an onsite review of plant maintenance, practices to complement the utility efforts in reducing outage time and increasing on-line operational time. Data were obtained from (1) observations during the 1977 refueling outage at Oconee 3, (2) review of maintenance practices during the Arkansas Nuclear One, Unit 1, operational cycle in 1977, and (3) selected observations of the 1978 refueling outage at ANO-1. Accumulated data were then reviewed and analyzed to produce a list of improvement recommendations for Oconee 3 and ANO-1 that can be generically applied to plants of similar design and construction.

Estimating the Propagation of Interdependent Cascading Outages with Multi-Type Branching Processes

Energy Technology Data Exchange (ETDEWEB)

Qi, Junjian; Ju, Wenyun; Sun, Kai

2016-01-01

In this paper, the multi-type branching process is applied to describe the statistics and interdependencies of line outages, the load shed, and isolated buses. The offspring mean matrix of the multi-type branching process is estimated by the Expectation Maximization (EM) algorithm and can quantify the extent of outage propagation. The joint distribution of two types of outages is estimated by the multi-type branching process via the Lagrange-Good inversion. The proposed model is tested with data generated by the AC OPA cascading simulations on the IEEE 118-bus system. The largest eigenvalues of the offspring mean matrix indicate that the system is closer to criticality when considering the interdependence of different types of outages. Compared with empirically estimating the joint distribution of the total outages, good estimate is obtained by using the multitype branching process with a much smaller number of cascades, thus greatly improving the efficiency. It is shown that the multitype branching process can effectively predict the distribution of the load shed and isolated buses and their conditional largest possible total outages even when there are no data of them.

Questions and perceptions about nuclear power plant outages

International Nuclear Information System (INIS)

Mc Donald, R.P.

1985-01-01

The most commonly used measure of nuclear power plant productivity is ''availability'' which is usually construed to be the percentage of time in a given period that a nuclear unit is actually tied to a grid supplying electrical power. When a unit is not tied to a grid, it is in an ''outage'' condition, possibly being shutdown, refueled, repaired, or in some stage of startup. There are some very positive by-products of well performed outages in addition to cost and availability enhancements: almost all supervisory and engineering personnel participate in planning and preparations. This approach promotes the professional and leadership development of each person, the supervisors and engineers participate in a competitive venture as a team and enjoy and benefit from comparative interactions with other utilities, perhaps the greatest benefit reaped from the development of outage management expertise is the improved ability to handle unexpected plant problems

World class performance: the outage/operating cycle continuum

Energy Technology Data Exchange (ETDEWEB)

Remphal, M. [Ontario Power Generation, Darlington, Ontario (Canada)

2011-07-01

It's all about Performance! Predictable and sustainable high performance is the key to public and stakeholder confidence in the nuclear industry. Why? Because nuclear is unique and safe, reliable operation each and every day is required to keep public trust. What better way to demonstrate this predictability than in breaker to breaker operating runs? Delivering on what was promised is the essence of our OPG accountability model: 'Say it, Do it'. This presentation is drawn from practical experience gained during the most recent planned maintenance outages at Darlington Nuclear. Key elements for outage success that will be discussed include; Human Performance: Ensuring each action is deliberate and executed right the first time; Continuous Learning: Recent examples demonstrating how drawing from lessons learned and operating experience worldwide can dramatically improve outage performance; Teamwork and Partnership: Recognizing our industry is too complex for a single; individual or organization to run on its own; Scope Selection: Darlington currently has an industry leading 0.5% Forced Loss Rate (FLR). If right work is selected and executed at the right time then ultimately the plant speaks and it shows up in low FLR and high Nuclear Performance Index; Planning: Ask and anticipate what can go wrong, what options exist and then pre-decide what path you would take. Some practical tools will be provided which have been recently used to plan out surprises; Oversight: An outage left to run its own course will have a surprise outcome. Strong management oversight is required to meet the goals of outage execution. Tips on how to improve communication and accountability will be discussed. Trust is built on confidence and confidence is built on sustainable performance. World class sustainable performance requires using all the tools available. This discussion will provide insight on these very tools. (author)

World class performance: the outage/operating cycle continuum

International Nuclear Information System (INIS)

Remphal, M.

2011-01-01

It's all about Performance! Predictable and sustainable high performance is the key to public and stakeholder confidence in the nuclear industry. Why? Because nuclear is unique and safe, reliable operation each and every day is required to keep public trust. What better way to demonstrate this predictability than in breaker to breaker operating runs? Delivering on what was promised is the essence of our OPG accountability model: 'Say it, Do it'. This presentation is drawn from practical experience gained during the most recent planned maintenance outages at Darlington Nuclear. Key elements for outage success that will be discussed include; Human Performance: Ensuring each action is deliberate and executed right the first time; Continuous Learning: Recent examples demonstrating how drawing from lessons learned and operating experience worldwide can dramatically improve outage performance; Teamwork and Partnership: Recognizing our industry is too complex for a single; individual or organization to run on its own; Scope Selection: Darlington currently has an industry leading 0.5% Forced Loss Rate (FLR). If right work is selected and executed at the right time then ultimately the plant speaks and it shows up in low FLR and high Nuclear Performance Index; Planning: Ask and anticipate what can go wrong, what options exist and then pre-decide what path you would take. Some practical tools will be provided which have been recently used to plan out surprises; Oversight: An outage left to run its own course will have a surprise outcome. Strong management oversight is required to meet the goals of outage execution. Tips on how to improve communication and accountability will be discussed. Trust is built on confidence and confidence is built on sustainable performance. World class sustainable performance requires using all the tools available. This discussion will provide insight on these very tools. (author)

Excellence through outage planning and scheduling

International Nuclear Information System (INIS)

Ferriole, G.

1987-01-01

The Nuclear and Fossil Generation Division of Electricite de France (EdF) has been the largest nuclear plant operating utility in France since 1984. The size of the units, their standardization, and extensive operating experience were favorable parameters leading to the development of a very complete maintenance organization. Electricite de France believes in the importance of well-defined maintenance concepts. These maintenance concepts contribute to outage performance by requiring a careful consideration of work to be done and by defining the techniques and means of accomplishing this work. In addition to maintenance concepts and careful planning and scheduling, good outage management is achieved through the motivation and dedication of the people involved. It is the key to good operational results

Verification and Enhancement of VIIRS Day-Night Band Power Outage Detection Product

Science.gov (United States)

Burke, A.; Schultz, L. A.; Omitaomu, O.; Molthan, A.; Cole, T.; Griffin, R.

2017-12-01

The NASA SPoRT (Short-term Prediction Research and Transition) Center has collaborated with scientists at NASA Goddard Space Flight Center to create a power outage detection product from radiance data obtained by the VIIRS (Visible Infrared Imaging Radiometer Suite) sensor aboard the Suomi-NPP satellite. This product uses a composite of pre-event radiance values from the VIIRS Day-Night Band to establish a baseline of "normal" nighttime lights for a study area. Then, after a severe weather event or other disaster, post-event images are compared to the composite to generate a percent-of-normal radiance product to identify areas that are experiencing outages and to aid in disaster response and monitor recovery. This project will use ground-truth county-level outage data provided by Oak Ridge National Laboratory (ORNL) in order validate the product and to establish a percent-of-normal threshold for identifying power outages. Once a threshold is found, ORNL's LandScan Global population data will be combined with the product to estimate how many electrical customers are being affected by power outages after a disaster. Two case studies will be explored to examine power outage recovery after severe weather events, including Hurricane Matthew from 2016 and the Washington D.C. Derecho event of 2012.

Status Report on the Development of Micro-Scheduling Software for the Advanced Outage Control Center Project

Energy Technology Data Exchange (ETDEWEB)

Germain, Shawn St. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Thomas, Kenneth [Idaho National Lab. (INL), Idaho Falls, ID (United States); Farris, Ronald [Idaho National Lab. (INL), Idaho Falls, ID (United States); Joe, Jeffrey [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2014-09-01

The long-term viability of existing nuclear power plants (NPPs) in the United States (U.S.) is dependent upon a number of factors, including maintaining high capacity factors, maintaining nuclear safety, and reducing operating costs, particularly those associated with refueling outages. Refueling outages typically take 20-30 days, and for existing light water NPPs in the U.S., the reactor cannot be in operation during the outage. Furthermore, given that many NPPs generate between $1-1.5 million/day in revenue when in operation, there is considerable interest in shortening the length of refueling outages. Yet, refueling outages are highly complex operations, involving multiple concurrent and dependent activities that are difficult to coordinate. Finding ways to improve refueling outage performance while maintaining nuclear safety has proven to be difficult. The Advanced Outage Control Center project is a research and development (R&D) demonstration activity under the Light Water Reactor Sustainability (LWRS) Program. LWRS is a R&D program which works with industry R&D programs to establish technical foundations for the licensing and managing of long-term, safe, and economical operation of current NPPs. The Advanced Outage Control Center project has the goal of improving the management of commercial NPP refueling outages. To accomplish this goal, this INL R&D project is developing an advanced outage control center (OCC) that is specifically designed to maximize the usefulness of communication and collaboration technologies for outage coordination and problem resolution activities. This report describes specific recent efforts to develop a capability called outage Micro-Scheduling. Micro-Scheduling is the ability to allocate and schedule outage support task resources on a sub-hour basis. Micro-Scheduling is the real-time fine-tuning of the outage schedule to react to the actual progress of the primary outage activities to ensure that support task resources are

Options for shortening nuclear power plant refueling outages

International Nuclear Information System (INIS)

Kastl, H.

2001-01-01

Deregulation of the European electricity market on 01.01.1999 forced a large number of electric utilities- especially nuclear power plant operators - to find ways of drastically cutting down their costs in order to be able to compete successfully within the new market environment. Nuclear power plants currently in operation mainly have three potential ways of reducing their power generating costs: by increasing plant availability, reducing fuel costs and cutting down operating costs. The optimization of plant refueling outages offers considerable potential for enhancing plant availability, but also helps bring down operating costs by reducing expenditure on maintenance. In order to optimize an outage in terms of its duration and costs, a variety of approaches are possible - all of which, however, involve certain key factors such as good organization, planning, logistics and control, improvement of equipment and tools, as well as motivation of personnel. Another aspect is the introduction of innovative technologies. In the last few years, such technologies have frequently enabled maintenance effort to be reduced, thus saving considerable time, and have also resulted in a need for fewer personnel to carry out the work, thus reducing radiation exposure. In many instances they have also improved the quality of work and outage performance as a whole. The paper uses recent examples to show how innovative technologies can contribute to-wards reducing nuclear plant maintenance costs and shorten the duration of refueling out-ages. (author)

Does Your Domestic Photovoltaic Energy System Survive Grid Outages?

Directory of Open Access Journals (Sweden)

Marijn R. Jongerden

2016-09-01

Full Text Available Domestic renewable energy systems, including photovoltaic energy generation, as well as local storage, are becoming increasingly popular and economically feasible, but do come with a wide range of options. Hence, it can be difficult to match their specification to specific customer’s needs. Next to the usage-specific demand profiles and location-specific production profiles, local energy storage through the use of batteries is becoming increasingly important, since it allows one to balance variations in production and demand, either locally or via the grid. Moreover, local storage can also help to ensure a continuous energy supply in the presence of grid outages, at least for a while. Hybrid Petri net (HPN models allow one to analyze the effect of different battery management strategies on the continuity of such energy systems in the case of grid outages. The current paper focuses on one of these strategies, the so-called smart strategy, that reserves a certain percentage of the battery capacity to be only used in case of grid outages. Additionally, we introduce a new strategy that makes better use of the reserved backup capacity, by reducing the demand in the presence of a grid outage through a prioritization mechanism. This new strategy, called power-save, only allows the essential (high-priority demand to draw from the battery during power outages. We show that this new strategy outperforms previously-proposed strategies through a careful analysis of a number of scenarios and for a selection of survivability measures, such as minimum survivability per day, number of survivable hours per day, minimum survivability per year and various survivability quantiles.

Practice of fuel management and outage strategy at Paks NPP

International Nuclear Information System (INIS)

Farago, P.; Hamvas, I.; Szecsenyi, Zs.; Nemes, I.; Javor, E.

2000-01-01

The Paks Nuclear Power Plant generates almost 40% of Hungarian electricity production at lowest price. In spite of this fact the reduction of operational and maintenance costs is one of the most important goal of the plant management. The proper fuel management and outage strategy can give a considerable influence for this cost reduction. The aim of loading pattern planning is to get the required cycle length with available fuel cassettes and to keep all key parameters of safety analysis under safety limits. Another important point is production at profit, where both the fuel and spent fuel cost are determining. Earlier the conditions given by our only fuel supplier restricted our possibilities, so at the beginning the fuel arrangement changing was the only way to improve efficiency of fuel using. As first step we introduced the low leakage core design. The next step was the 4 years cycle using of some cassettes. By this way nearly half of 3 years cycle old cassettes remained in the core for fourth cycle. In the immediate future we want to use profiled cassettes developed by Russian supplier. Simultaneously we will load new type of WWER cassettes with burnable poison developed by BNFL Company. Hereby we can apply more BNFL cassettes for four years cycle even more. Both cost of fuel and number of spent fuel can be reduced besides keeping parameters under safety limits. The Hungarian in service inspection rules determine that every four year we have to make a complete inspection of reactor vessel. Therefore earlier we had two types of outages. Every 4 years we planned a long outage with 55-65 days duration and normal ones with about 30-35 days duration between the long ones. During the normal outages this way did not give us enough room to utilise the shortest possible critical path determined by works on reactor. Some years ago we changed our outage strategy. Now we plan every 4 years a long outage, and between them one normal and two short ones. As a result the

Impacts of organization and management on outage performance

International Nuclear Information System (INIS)

Huang Yuhao; Cheng, S.-K.

2004-01-01

From probabilistic safety assessments and root cause analyses for incidents/accidents, the risk at refueling outage has recently been recognized to be comparable to (or even more significant than) the commonly evaluated risk at power in a Nuclear Power Plant (NPP). This paper summarizes the major findings in the aspect of 'organization and management', which is identified to have significant impacts on outage performance in the qualitative assessment of a PWR plant. In order to reduce the potential risk arisen from those identified imperfections, the corresponding suggestions are also proposed. (author)

Development of an Overview Display to Allow Advanced Outage Control Center Management to Quickly Evaluate Outage Status

Energy Technology Data Exchange (ETDEWEB)

St Germain, Shawn Walter [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hugo, Jacques Victor [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2016-09-01

This report describes recent advances made in developing a framework for the design of visual outage information presentation, as well as an overview of the scientific principles that informed the development of the visualizations.

Commercial operation and outage experience of ABWR at Kashiwazaki-Kariwa units Nos. 6 and 7

International Nuclear Information System (INIS)

Anahara, N.; Yamada, M.; Kataoka, H.

2000-01-01

Kashiwazaki-Kariwa Nuclear Power Station Units Nos. 6 and 7, the world's first ABWRs (Advanced Boiling Water Reactor), started commercial operation on November 7, 1996 and July 2, 1997, respectively, and continued their commercial operation with a high capacity factor, low occupational radiation exposure and radioactive waste. Units 6 and 7 were in their 3rd cycle operation until 25th April 1999 and 1st November 1999, respectively. Thermal efficiency was 35.4-35.8% (design thermal efficiency: 34.5%) during these period, demonstrating better performance than that of BWR-5 (design thermal efficiency: 33.4%). Nos. 6 and 7 have experienced 2 annual outages. The first outage of unit No. 6 started on November 20, 1997 and was completed within 61 days (including 6 New Year holidays), and the second outage started on March 13, 1999 and was completed within 44 days. The first annual outage of unit No. 7 started on May 27, 1998, earlier than it would normally have been, to avoid an annual outage during the summer, and was completed within 55 days, and the second outage started on September 18th, 1999 and was completed within 45 days, All annual outages were carried out within a very short time period without any severe malfunctions, including newly designed ABWR systems and equipment. As the first outage in Japan, 55 days is a very short period, despite the fact that the Nos. 6 and 7 are the first ABWRs in the world and the largest capacity units in Japan. The total occupational radiation exposure of No. 6 was 300 man-mSv (1st outage) and 331 man-mSv (2nd outage). That of Unit 7 was 153 man-mSv (1st outage) Those of unit No. 6 were at the same level as those of unit No. 3, which is the latest design 1100MW(e) BWR-5. That of unit No. 7 was the lowest ever at Kashiwazaki-Kariwa nuclear power station. The drums of radioactive waste discharged during the annual outage numbered 54 (1st outage) for No. 6 and 62 (1st outage) for No. 7, which was less than the design target of 100

Hybrid Cascading Outage Analysis of Extreme Events with Optimized Corrective Actions

Energy Technology Data Exchange (ETDEWEB)

Vallem, Mallikarjuna R.; Vyakaranam, Bharat GNVSR; Holzer, Jesse T.; Samaan, Nader A.; Makarov, Yuri V.; Diao, Ruisheng; Huang, Qiuhua; Ke, Xinda

2017-10-19

Power system are vulnerable to extreme contingencies (like an outage of a major generating substation) that can cause significant generation and load loss and can lead to further cascading outages of other transmission facilities and generators in the system. Some cascading outages are seen within minutes following a major contingency, which may not be captured exclusively using the dynamic simulation of the power system. The utilities plan for contingencies either based on dynamic or steady state analysis separately which may not accurately capture the impact of one process on the other. We address this gap in cascading outage analysis by developing Dynamic Contingency Analysis Tool (DCAT) that can analyze hybrid dynamic and steady state behavior of the power system, including protection system models in dynamic simulations, and simulating corrective actions in post-transient steady state conditions. One of the important implemented steady state processes is to mimic operator corrective actions to mitigate aggravated states caused by dynamic cascading. This paper presents an Optimal Power Flow (OPF) based formulation for selecting corrective actions that utility operators can take during major contingency and thus automate the hybrid dynamic-steady state cascading outage process. The improved DCAT framework with OPF based corrective actions is demonstrated on IEEE 300 bus test system.

Next generation sequencing identifies abnormal Y chromosome and candidate causal variants in premature ovarian failure patients.

Science.gov (United States)

Lee, Yujung; Kim, Changshin; Park, YoungJoon; Pyun, Jung-A; Kwack, KyuBum

2016-12-01

Premature ovarian failure (POF) is characterized by heterogeneous genetic causes such as chromosomal abnormalities and variants in causal genes. Recently, development of techniques made next generation sequencing (NGS) possible to detect genome wide variants including chromosomal abnormalities. Among 37 Korean POF patients, XY karyotype with distal part deletions of Y chromosome, Yp11.32-31 and Yp12 end part, was observed in two patients through NGS. Six deleterious variants in POF genes were also detected which might explain the pathogenesis of POF with abnormalities in the sex chromosomes. Additionally, the two POF patients had no mutation in SRY but three non-synonymous variants were detected in genes regarding sex reversal. These findings suggest candidate causes of POF and sex reversal and show the propriety of NGS to approach the heterogeneous pathogenesis of POF. Copyright © 2016 Elsevier Inc. All rights reserved.

Outage performance of reactive cooperation in Nakagami-m fading channels

KAUST Repository

Benjillali, Mustapha

2010-06-01

In this paper, we investigate the outage performance of Decode-and-Forward with reactive relaying in dual-hop cooperetive Nakagaml-m fading links. The destination, based on the umque knowledge of local second hop channel state information, selects the best relay to increase the chances of cooperation when the direct link is also available. After deriving the exact distribution of the variables of interest, the outage probability of the system - with and without the direct link - is obtained in closed-form, and the ε-outage capacity is derived in the particular c.se wh.ere the channel model is reduced to a Rayleigh fading. Simulation results confirm the accuracy of our analysis for a large selection of system and fading parameters.

Wolsong Unit 1 restart chemistry procedures during retubing outage

International Nuclear Information System (INIS)

Yun, Hyunran; Lee, Sarang; Moon, Yunyong; Kim, Seoyul

2015-01-01

Lay-up is aimed at protecting systems from degradation during outage, mainly by minimizing corrosion and particularly, when the outage is longer than 16 weeks. Due to the intrinsic design of CANDU reactors, their horizontal fuel channels should be replaced for another service life time. This poster presents the lay-up guidelines and methods recommended for re-tubing outage based on the first re-tubing operation made in Korea (at the Wolsung Unit 1). It is shown that dry lay-up with specific gas blanket was the sole choice for the primary heat transfer system, the moderator system and the steam cycle system while wet lay-up under circulation was recommended for the end shield cooling system and the liquid zone control system. The water filled part of steam generators, of the liquid zone control system and of the end shield cooling system was maintained normal

Ratepayers should not fund IP-2 outage, NY Attorney General says

International Nuclear Information System (INIS)

Anon.

1981-01-01

The New York Attorney General is trying to block Consolidated Edison's effort to pay for an Indian Point nuclear plant outage through the fuel-adjustment clause on the grounds that the utility had repeated system warnings and should have taken action to prevent the leakage of water into the containment building. The utility rejects the assessment of personnel negligence and, blaming equipment failure, plans to replace its heat exchangers. The New York Public Service Commission approved Con Ed's use of the fuel-adjustment clause to pay for replacement power, but agrees that ratepayers should not pay the costs of negligence if the charges are proved. The Attorney General feels that Con Ed could legally challenge a later request for refunds. Other funding possibilities include nuclear-insurance policies or legal action against the equipment manufacturer

Outage Analysis of Spectrum-Sharing over M-Block Fading with Sensing Information

KAUST Repository

Alabbasi, Abdulrahman

2016-07-13

Future wireless technologies, such as, 5G, are expected to support real-time applications with high data throughput, e.g., holographic meetings. From a bandwidth perspective, cognitive radio is a promising technology to enhance the system’s throughput via sharing the licensed spectrum. From a delay perspective, it is well known that increasing the number of decoding blocks will improve the system robustness against errors, while increasing the delay. Therefore, optimally allocating the resources to determine the tradeoff of tuning the length of decoding blocks while sharing the spectrum is a critical challenge for future wireless systems. In this work, we minimize the targeted outage probability over the block-fading channels while utilizing the spectrum-sharing concept. The secondary user’s outage region and the corresponding optimal power are derived, over twoblocks and M-blocks fading channels. We propose two suboptimal power strategies and derive the associated asymptotic lower and upper bounds on the outage probability with tractable expressions. These bounds allow us to derive the exact diversity order of the secondary user’s outage probability. To further enhance the system’s performance, we also investigate the impact of including the sensing information on the outage problem. The outage problem is then solved via proposing an alternating optimization algorithm, which utilizes the verified strict quasiconvex structure of the problem. Selected numerical results are presented to characterize the system’s behavior and show the improvements of several sharing concepts.

Collagen type I alpha 1 gene polymorphism in premature ovarian failure

Directory of Open Access Journals (Sweden)

Vujović Svetlana

2013-01-01

Full Text Available Introduction. Premature ovarian failure (POF is characterized by amenorrhea, hypergonadotropism and hypoestrogenism in women bellow 40 years. Osteoporosis is one of the late complications of POF. Objective. To correlate collagen type I alpha1 (COLIA1 gene polymorphism with bone mineral density (BMD in women with POF. Methods. We determined the COLIA1 genotypes SS, Ss, ss in 66 women with POF. Single nucleotide polymorphism (G to T substitution within the Sp 1-binding site in the first intron of the COLIA1 gene was assessed by polymerase chain reaction (PCR followed by single-stranded conformation polymorphism (SSCP analysis. Bone mineral density (BMD was measured at the lumbar spine region by dual X-ray absorptiometry. Statistics: Kruskal-Wallis ANOVA, Chisquare test, Spearman correlation test. Results. The relative distribution of COLIA1 genotype alleles was SS - 54.4%, Ss - 41.0% and ss - 4.5%. No significant differences were found between genotype groups in body mass index, age, duration of amenorrhea or BMD. A significant positive correlation was observed between BMI and parity. Conclusion. The COLIA1 gene is just one of many genes influencing bone characteristics. It may act as a marker for differences in bone quantity and quality, bone fragility and accelerated bone loss in older women. However, in young women with POF, COLIA1 cannot identify those at higher risk for osteoporosis. [Projekat Ministarstva nauke Republike Srbije, br. ON 173056

Outage Analysis of Spectrum-Sharing over M-Block Fading with Sensing Information

KAUST Repository

Alabbasi, Abdulrahman; Rezki, Zouheir; Shihada, Basem

2016-01-01

on the outage probability with tractable expressions. These bounds allow us to derive the exact diversity order of the secondary user’s outage probability. To further enhance the system’s performance, we also investigate the impact of including the sensing

Estimating the spatial distribution of power outages during hurricanes in the Gulf coast region

International Nuclear Information System (INIS)

Han, S.-R.; Guikema, Seth D.; Quiring, Steven M.; Lee, Kyung-Ho; Rosowsky, David; Davidson, Rachel A.

2009-01-01

Hurricanes have caused severe damage to the electric power system throughout the Gulf coast region of the US, and electric power is critical to post-hurricane disaster response as well as to long-term recovery for impacted areas. Managing power outage risk and preparing for post-storm recovery efforts requires accurate methods for estimating the number and location of power outages. This paper builds on past work on statistical power outage estimation models to develop, test, and demonstrate a statistical power outage risk estimation model for the Gulf Coast region of the US. Previous work used binary hurricane-indicator variables representing particular hurricanes in order to achieve a good fit to the past data. To use these models for predicting power outages during future hurricanes, one must implicitly assume that an approaching hurricane is similar to the average of the past hurricanes. The model developed in this paper replaces these indicator variables with physically measurable variables, enabling future predictions to be based on only well-understood characteristics of hurricanes. The models were developed using data about power outages during nine hurricanes in three states served by a large, investor-owned utility company in the Gulf Coast region

Outages 1999 and 2000, investments in safety and long-term operation of NE Krsko

International Nuclear Information System (INIS)

Sirola, P.; Krajnc, J.; Androjna, F.

1999-01-01

Plant outage is an important part of nuclear power plant operation. During that time the conditions are established for the performance of specific activities, such as refueling, tests, inspections, preventive and corrective maintenance and modifications, that are intended to confirm proper condition and availability of safety and other important components and improve overall plant safety and reliability. It is well know that in Nuclear Power Plant Krsko (Nuklearna elektrarna Krsko NEK) during Outage 2000 new Steam Generators (SGs) will be placed in service, while Outage '99 was used for preparatory works. But the importance of those two outages is even greater, because they are implementing a broad number of improvements and establishing a basis for long-term plant operation. Outage '99 required very detailed planning to assure a good control over the outage activities and operational plant systems necessary for safe shutdown. Numerous activities took place in a relatively narrow space in the Reactor Building. Some of these activities will have a big significance for the future. The article treats the status update and summarizes the specifics and importance of the mentioned activities to long-term plant safe and reliable operation.(author)

Satellite failures revisited

Science.gov (United States)

Balcerak, Ernie

2012-12-01

In January 1994, the two geostationary satellites known as Anik-E1 and Anik-E2, operated by Telesat Canada, failed one after the other within 9 hours, leaving many northern Canadian communities without television and data services. The outage, which shut down much of the country's broadcast television for hours and cost Telesat Canada more than $15 million, generated significant media attention. Lam et al. used publicly available records to revisit the event; they looked at failure details, media coverage, recovery effort, and cost. They also used satellite and ground data to determine the precise causes of those satellite failures. The researchers traced the entire space weather event from conditions on the Sun through the interplanetary medium to the particle environment in geostationary orbit.

World-class outage performance of the Olkiluoto nuclear power plant

International Nuclear Information System (INIS)

Paavola, M.

1998-01-01

The production of the Olkiluoto power plant units covered 17% of the electricity consumption in Finland in 1997; the total share of nuclear energy was 27% of the electricity consumed in the country. Based on Finnish experience, nuclear energy is a safe, environmentally friendly and economic way to produce electricity provided that the plants and their personnel are well taken care of. TVO's policy is to keep the plant units in good condition and technically modern. This requires continuous investments in the plant. In maintenance, attention is paid to monitoring the condition of the plant and to preventive maintenance aiming at avoiding disturbances in production. TVO has chosen continuous development as the operational line develops the plant by annual investments and performs the necessary modifications during planned annual outages trying to avoid long production interruptions. The load factors of the Olkiluoto nuclear power plant have been high. The average load factor during the last decade was over 93%. The most significant single factor in the production deficits is the amount or electricity, which has not been produced because of the annual outages. Due to this, special attention has been paid to the performance of the annual outages. TVO aims at continuous development of the annual outage procedure. A centralized task management system makes it possible to perform simultaneously more tasks than before. The company has also invested in equipment and systems, which ease and speed up servicing. Normal outage length varies between 10 and 16 days. By keeping the plant units as modern as possible and in good condition we facilitate reaching TVO's target, which is also stated in TVO's slogan 'always 40 years lifetime'. (author)

Optimization of safety equipment outages improves safety

International Nuclear Information System (INIS)

Cepin, Marko

2002-01-01

Testing and maintenance activities of safety equipment in nuclear power plants are an important potential for risk and cost reduction. An optimization method is presented based on the simulated annealing algorithm. The method determines the optimal schedule of safety equipment outages due to testing and maintenance based on minimization of selected risk measure. The mean value of the selected time dependent risk measure represents the objective function of the optimization. The time dependent function of the selected risk measure is obtained from probabilistic safety assessment, i.e. the fault tree analysis at the system level and the fault tree/event tree analysis at the plant level, both extended with inclusion of time requirements. Results of several examples showed that it is possible to reduce risk by application of the proposed method. Because of large uncertainties in the probabilistic safety assessment, the most important result of the method may not be a selection of the most suitable schedule of safety equipment outages among those, which results in similarly low risk. But, it may be a prevention of such schedules of safety equipment outages, which result in high risk. Such finding increases the importance of evaluation speed versus the requirement of getting always the global optimum no matter if it is only slightly better that certain local one

Study of Arkansas Nuclear One-1 13th refueling outage

International Nuclear Information System (INIS)

Hashiba, Takashi

1997-01-01

Recently performance of nuclear power plants in the USA has improved remarkably. Their average automatic shutdown rate has been sharply dropping, although it is still higher than that in Japan, and their average capacity factor has become higher than that in Japan in recent years. One of the main contributors is an extension of the operational period, and another is a shortening of refueling-outage time. It is considerably difficult to have accomplished both the improvement of plant reliability and shortening of refueling-outage time because their refueling outage corresponds to our periodical inspection which is central to maintenance activities in Japanese plants. In order to learn how they have been achieved, a visit to Arkansas Nuclear One-1 (ANO-1) which obtained the top-class result of SALP (Systematic Assessment of Licensee Performance) performed by the Nuclear Regulatory Commission was planned and study of their 13th refueling outage was carried out. Their achievements result from performance-base maintenance and on-line maintenance, based on a proper preventive maintenance program, and untiring efforts of efficiency improvement, represented by the introduction of several on-line systems. And the reason behind this is severe competition concerning power generation cost reduction. (author)

Study of Arkansas Nuclear One-1 13th refueling outage

Energy Technology Data Exchange (ETDEWEB)

Hashiba, Takashi [Institute of Nuclear Safety System Inc., Seika, Kyoto (Japan)

1997-09-01

Recently performance of nuclear power plants in the USA has improved remarkably. Their average automatic shutdown rate has been sharply dropping, although it is still higher than that in Japan, and their average capacity factor has become higher than that in Japan in recent years. One of the main contributors is an extension of the operational period, and another is a shortening of refueling-outage time. It is considerably difficult to have accomplished both the improvement of plant reliability and shortening of refueling-outage time because their refueling outage corresponds to our periodical inspection which is central to maintenance activities in Japanese plants. In order to learn how they have been achieved, a visit to Arkansas Nuclear One-1 (ANO-1) which obtained the top-class result of SALP (Systematic Assessment of Licensee Performance) performed by the Nuclear Regulatory Commission was planned and study of their 13th refueling outage was carried out. Their achievements result from performance-base maintenance and on-line maintenance, based on a proper preventive maintenance program, and untiring efforts of efficiency improvement, represented by the introduction of several on-line systems. And the reason behind this is severe competition concerning power generation cost reduction. (author)

Outage Performance of Flexible OFDM Schemes in Packet-Switched Transmissions

Directory of Open Access Journals (Sweden)

Romain Couillet

2009-01-01

Full Text Available α-OFDM, a generalization of the OFDM modulation, is proposed. This new modulation enhances the outage capacity performance of bursty communications. The α-OFDM scheme is easily implementable as it only requires an additional time symbol rotation after the IDFT stage and a subsequent phase rotation of the cyclic prefix. The physical effect of the induced rotation is to slide the DFT window over the frequency spectrum. When successively used with different angles α at the symbol rate, α-OFDM provides frequency diversity in block fading channels. Interestingly, simulation results show a substantial gain in terms of outage capacity and outage BER in comparison with classical OFDM modulation schemes. The framework is extended to multiantenna and multicellular OFDM-based standards. Practical simulations, in the context of 3GPP-LTE, called hereafter α-LTE, sustain our theoretical claims.

Premature ovarian failure, short stature, and Hashimoto's disease in an 18-year-old adolescent girl with 46, X, i(X)(q10).

Science.gov (United States)

Hu, Xiang; Zhang, Qiao; Gao, Feng; Chen, Lu-Lu

2018-04-22

Premature ovarian failure (POF) is a heterogeneous condition affecting girls and women. We detected a previously healthy 18-year-old adolescent girl, presented with amenorrhea over six months, as well as circulating levels of estradiol lower decreased and follicle-stimulating hormone (FSH) increased. She was 138 cm tall. Results of laboratory tests and/or ultrasound investigations showed 46, X, i(X)(q10) karyotype and Hashimoto's disease. This case suggests that pubertal onset and progression, as well as karyotype analysis, should be evaluated in girls with Hashimoto's disease and short stature.

Outage capacity of multicarrier systems

KAUST Repository

Yilmaz, Ferkan; Alouini, Mohamed-Slim

2010-01-01

The probability density function and the cumulative distribution function of the product of shifted Gamma variates are obtained in terms of the generalized Fox's H function. Using these new results, the exact outage capacity of multi carrier transmission through a slow Nakagami-m fading channel is presented. Moreover, it is shown that analytical and simulation results are in perfect agreement. © 2009 IEEE.

Allowable outage analysis for the LOFT CIS and reflood assist bypass valves

International Nuclear Information System (INIS)

Trainer, J.E.; Matthews, S.D.

1977-06-01

To determine the outage time allowable for a typical 1 of 2 redundant valve configuration, a Markov model was created to analyze the various operating states for the valves. Since no performance criteria have been specified, an availability model was constructed with regard to the valve outage

Upgrading BWR training simulators for annual outage operation training

International Nuclear Information System (INIS)

Yamakabe, K.; Nakajima, A.; Shiyama, H.; Noji, K.; Okabe, N.; Murata, F.

2006-01-01

Based upon the recently developed quality assurance program by the Japanese electric companies, BWR Operator Training Center (BTC) identified the needs to enhance operators' knowledge and skills for operations tasks during annual outage, and started to develop a dedicated operator training course specialized for them. In this paper, we present the total framework of the training course for annual outage operations and the associated typical three functions of our full-scope simulators specially developed and upgraded to conduct the training; namely, (1) Simulation model upgrade for the flow and temperature behavior concerning residual heat removal (RHR) system with shutdown cooling mode, (2) Addition of malfunctions for DC power supply equipment, (3) Simulation model upgrade for water filling operation for reactor pressurization (future development). We have implemented a trial of the training course by using the upgraded 800MW full-scope training simulator with functions (1) and (2) above. As the result of this trial, we are confident that the developed training course is effective for enhancing operators' knowledge and skills for operations tasks during annual outage. (author)

Health and maintenance outages in nuclear power plants: an epidemiological survey

International Nuclear Information System (INIS)

Telle, M.A.; Huez, D.; Niedbala, J.M.; Auclair, J.; Canales, J.P.; Duverge, C.; Forest, H.; Gerondal, M.; Paris, P.M.; Renault, J.C.; Bossevain, L.; Blaise, P.; Blanc, M.C.; Goldberg, M.; Charpak, Y.

1995-01-01

An epidemiological survey, started in 1989, was carried out at the nuclear power plants in the Loire river valley and at Le Blayais (France). Working conditions, work organisation and their impact on health during annual maintenance outages were studied. The main areas covered in this cross-sectional study were: anxiety and symptoms of depression using the Spielberger and CES-D scales. Comparisons were made during both a scheduled outage and in normal operation on four distinct groups of workers, each individual being his own control. A chi-square test was used for the quantitative variables and a test on differences for the quantitative variables. During a unit outage, more frequent overtime and atypical working hours were reported (p<0.01); working rhythms and safety rules were felt as more restrictive and exposure to radiation higher (p<0.01). Detrimental modifications of anxiety and symptoms of depression were observed on controllers whereas expected on maintenance agents. Similar results were observed when considering the rates of outages. Possible readings are given with reference to qualitative studies carried out on this topic, which implies extending our research with both the quantitative and qualitative approaches. (authors). 10 refs., 6 tabs

Outage capacity of multicarrier systems

KAUST Repository

Yilmaz, Ferkan

2010-01-01

The probability density function and the cumulative distribution function of the product of shifted Gamma variates are obtained in terms of the generalized Fox\\'s H function. Using these new results, the exact outage capacity of multi carrier transmission through a slow Nakagami-m fading channel is presented. Moreover, it is shown that analytical and simulation results are in perfect agreement. © 2009 IEEE.

Outage Analysis of Asymmetric RF-FSO Systems

KAUST Repository

Ansari, Imran Shafique; Abdallah, Mohamed M.; Alouini, Mohamed-Slim; Qaraqe, Khalid A.

2017-01-01

In this work, the outage performance analysis of a dual-hop transmission system composed of asymmetric radio frequency (RF) channels cascaded with free-space optical (FSO) links is presented. The RF links are modeled by the Rayleigh fading

Enhanced outage prediction modeling for strong extratropical storms and hurricanes in the Northeastern United States

Science.gov (United States)

Cerrai, D.; Anagnostou, E. N.; Wanik, D. W.; Bhuiyan, M. A. E.; Zhang, X.; Yang, J.; Astitha, M.; Frediani, M. E.; Schwartz, C. S.; Pardakhti, M.

2016-12-01

The overwhelming majority of human activities need reliable electric power. Severe weather events can cause power outages, resulting in substantial economic losses and a temporary worsening of living conditions. Accurate prediction of these events and the communication of forecasted impacts to the affected utilities is necessary for efficient emergency preparedness and mitigation. The University of Connecticut Outage Prediction Model (OPM) uses regression tree models, high-resolution weather reanalysis and real-time weather forecasts (WRF and NCAR ensemble), airport station data, vegetation and electric grid characteristics and historical outage data to forecast the number and spatial distribution of outages in the power distribution grid located within dense vegetation. Recent OPM improvements consist of improved storm classification and addition of new predictive weather-related variables and are demonstrated using a leave-one-storm-out cross-validation based on 130 severe extratropical storms and two hurricanes (Sandy and Irene) in the Northeast US. We show that it is possible to predict the number of trouble spots causing outages in the electric grid with a median absolute percentage error as low as 27% for some storm types, and at most around 40%, in a scale that varies between four orders of magnitude, from few outages to tens of thousands. This outage information can be communicated to the electric utility to manage allocation of crews and equipment and minimize the recovery time for an upcoming storm hazard.

High-Temperature Graphitization Failure of Primary Superheater Tube

Science.gov (United States)

Ghosh, D.; Ray, S.; Roy, H.; Mandal, N.; Shukla, A. K.

2015-12-01

Failure of boiler tubes is the main cause of unit outages of the plant, which further affects the reliability, availability and safety of the unit. So failure analysis of boiler tubes is absolutely essential to predict the root cause of the failure and the steps are taken for future remedial action to prevent the failure in near future. This paper investigates the probable cause/causes of failure of the primary superheater tube in a thermal power plant boiler. Visual inspection, dimensional measurement, chemical analysis, metallographic examination and hardness measurement are conducted as the part of the investigative studies. Apart from these tests, mechanical testing and fractographic analysis are also conducted as supplements. Finally, it is concluded that the superheater tube is failed due to graphitization for prolonged exposure of the tube at higher temperature.

Use of a Computerized Tool (ORAM) to Help Manage Outage Safety and Risk at NPP Krsko

International Nuclear Information System (INIS)

Spiler, J.; Basic, I.; Vrbanic, I.; Fifnja, I.; Kastelan, M.; Dagan, W. J.; Shanley, L. B.; Naum, T. J.

1998-01-01

Outage Risk Assessment and Management (ORAM) is a computerized methodology developed by the U.S. Electric Power Research Institute (EPRI) to help Nuclear Power Plant personnel manage the risk and safety associated with refueling and forced plant outages. Today, over 60 plants including NPP Krsko are using ORAM during the preparation and performance of plant outages. In fact, many plants are attributing much of the reductions in the duration of refueling outages to the use of ORAM. The success of the ORAM methodology is the capability to provide plant and management personnel with understandable results from both deterministic evaluations of plant safety and quantitative risk assessments. The Nuklearna Elektrarna Krsko (NEK) use of ORAM involves both of these approaches. The deterministic portion of ORAM is used to model the NPP Krsko Shutdown Technical Specifications and administrative considerations. The probabilistic portion of ORAM uses industry and NEK specific initiating events and other risk elements pertaining to shutdown to derive a quantitative risk assessment for various end states, including core damage and RCS boiling. This paper expands on the value of each approach and demonstrates the benefits of combining these elements in the decision-making process. Another key advantage of ORAM is the ability to apply the methodology to specific outages. Since no outage is identical, this provides tremendous benefits to plant personnel for managing the safety and risk of a particular outage. ORAM does this ba organizing all of the various plant configurations and equipment unavailability windows into numerous plant states. Furthermore, ORAM evaluations can be a utomated b y interfacing with outage scheduling software programs such as Primavera. For each plant state, the deterministic and the probabilistic logic evaluations are applied. This paper will demonstrate the ORAM evaluation for an actual NPP Krsko outage. (author)

Outage analysis of opportunistic decode-and-forward relaying

KAUST Repository

Tourki, Kamel

2010-09-01

In this paper, we investigate a dual-hop opportunistic decode-and-forward relaying scheme where the source may or not be able to communicate directly with the destination. We first derive statistics based on exact probability density function (PDF) of each hop. Then, the PDFs are used to determine closed-form outage probability expression for a transmission rate R. Furthermore, we evaluate the asymptotic outage performance and the diversity order is deduced. Unlike existing works where the analysis focused on high signal-to-noise ratio (SNR) regime, such results are important to enable the designers to take decisions regarding practical systems that operate at low SNR regime. We show that performance simulation results coincide with our analytical results under practical assumption of unbalanced hops. © 2010 IEEE.

Premature menopause.

Science.gov (United States)

Okeke, Tc; Anyaehie, Ub; Ezenyeaku, Cc

2013-01-01

Premature menopause affects 1% of women under the age of 40 years. The women are at risk of premature death, neurological diseases, psychosexual dysfunction, mood disorders, osteoporosis, ischemic heart disease and infertility. There is need to use simplified protocols and improved techniques in oocyte donation to achieve pregnancy and mother a baby in those women at risk. Review of the pertinent literature on premature menopause, selected references, internet services using the PubMed and Medline databases were included in this review. In the past, pregnancy in women with premature menopause was rare but with recent advancement in oocyte donation, women with premature menopause now have hoped to mother a child. Hormone replacement therapy is beneficial to adverse consequences of premature menopause. Women with premature menopause are at risk of premature death, neurological diseases, psychosexual dysfunction, mood disorders, osteoporosis, ischemic heart disease and infertility. Public enlightenment and education is important tool to save those at risk.

Outage analysis of blind cooperative diversity

KAUST Repository

Tourki, Kamel; Alouini, Mohamed-Slim

2011-01-01

Mobile users with single antennas can still take advantage of spatial diversity through cooperative space-time-encoded transmission. In this paper, we considered a scheme in which a relay chooses to cooperate only if its source-relay channel is of an acceptable quality, and we evaluate the usefulness of relaying when the source acts blindly and ignores the decision of the relays whether they may cooperate or not. In our study, we consider the regenerative relays in which the decisions to cooperate are based on a targeted end-to-end data rate R. We derived the end-to-end outage probability for a transmission rate R and a code rate ρ and look at a power allocation strategy between the source and the relays in order to minimize the end-to-end outage probability at the destination for high signal-to-noise ratio, by using the golden section search method. Performance results show that the computer simulations-based results coincide with our analytical results. Copyright © 2011 John Wiley & Sons, Ltd.

Outage analysis of blind cooperative diversity

KAUST Repository

Tourki, Kamel

2011-06-06

Mobile users with single antennas can still take advantage of spatial diversity through cooperative space-time-encoded transmission. In this paper, we considered a scheme in which a relay chooses to cooperate only if its source-relay channel is of an acceptable quality, and we evaluate the usefulness of relaying when the source acts blindly and ignores the decision of the relays whether they may cooperate or not. In our study, we consider the regenerative relays in which the decisions to cooperate are based on a targeted end-to-end data rate R. We derived the end-to-end outage probability for a transmission rate R and a code rate ρ and look at a power allocation strategy between the source and the relays in order to minimize the end-to-end outage probability at the destination for high signal-to-noise ratio, by using the golden section search method. Performance results show that the computer simulations-based results coincide with our analytical results. Copyright © 2011 John Wiley & Sons, Ltd.

Premature saturation in backpropagation networks: Mechanism and necessary conditions

International Nuclear Information System (INIS)

Vitela, J.E.; Reifman, J.

1997-01-01

The mechanism that gives rise to the phenomenon of premature saturation of the output units of feedforward multilayer neural networks during training with the standard backpropagation algorithm is described. The entire process of premature saturation is characterized by three distinct stages and it is concluded that the momentum term plays the leading role in the occurrence of the phenomenon. The necessary conditions for the occurrence of premature saturation are presented and a new method is proposed, based on these conditions, that eliminates the occurrence of the phenomenon. Validity of the conditions and the proposed method are illustrated through simulation results. Three case studies are presented. The first two came from a training session for classification of three component failures in a nuclear power plant. The last case, comes from a training session for classification of welded fuel elements

Ontario-U.S. power outages : impacts on critical infrastructure

International Nuclear Information System (INIS)

2006-01-01

This paper described the power outage and resulting blackout that occurred on August 14, 2003 and identified how critical infrastructure was directly and interdependently impacted in Canada. The aim of the paper was to assist critical infrastructure protection and emergency management professionals in assessing the potential impacts of large-scale critical infrastructure disruptions. Information for the study was acquired from Canadian and American media reports and cross-sectoral information sharing with provincial and federal governments and the private sector. The blackout impacted most of the sources and means of generating, transmitting and distributing power within the area, which in turn impacted all critical infrastructure sectors. Landline and cellular companies experienced operational difficulties, which meant that emergency responders were impacted. Newspapers and the electronic media struggled to release information to the public. The banking and finance industry experienced an immediate degradation of services. The power outage caused shipping and storage difficulties for commercial retailers and dairy producers. A number of incidents were reported where only partially treated waste water was released into neighbouring waterways. The timing of the blackout coincided with the closures of workplaces and created additional difficulties on transportation networks. Many gas station pumps were inoperable. Police, fire departments and ambulance services experienced a dramatic increase in the volume of calls received, and all branches of the emergency services sector encountered transportation delays and difficulties with communications equipment. Nuclear reactors were also impacted. An estimated 150,000 Government of Canada employees were unable to report to work. Estimates have indicated that the power outage cost Ontario's economy between $1 and $2 billion. The outage negatively impacted 82 per cent of small businesses in Ontario. 170 refs., 3 figs

Prematurity as a factor of damaged child development

Directory of Open Access Journals (Sweden)

Chukhutova G.L.

2015-03-01

Full Text Available At present time prematurity is the main reason for disability in children, which can be exemplified by the fact that 2/3 of educatees of children' homes for blind and deaf are preterm children. The most drastic consequences of prematurity is cerebral palsy with spastic diplegia; blindness or poor vision as a result of retina detachment; auditory inefficiency connected with the nerve deafness, decline in general cognitive and speech development; difficulties in coordination and planning serial operations; psycho-emotional impairments like autism. The distinctive features of appearance (failure to thrive, microcephalism with deformation of the shape of the head and behavior (stereotyped movements, lack in initiative purposeful activity make these children recognizable and let us talk about naturally determined set of impairments connected with the main reason — prematurity. The article regards the influence of preterm birth on child's nervous system and it's remote effect on his/her psychic development.

Bingham Pump Outage Pits: Environmental information document

International Nuclear Information System (INIS)

Pekkala, R.O.; Jewell, C.E.; Holmes, W.G.; Marine, I.W.

1987-03-01

Seven waste sites known as the Bingham Pump Outage Pits located in areas of the Savannah River Plant (SRP) received solid waste containing an estimated 4 Ci of low-level radioactivity in 1957-1958. These sites were subsequently backfilled and have been inactive since that time. Most of the radioactivity at the Bingham Pump Outage Pits has been eliminated by radioactive decay. A total of approximately 1 Ci of activity (primarily 137 Cs and 90 Sr) is estimated to remain at the seven sites. The closure options considered for the Bingham Pump Outage Pits are waste removal and closure, no waste removal and closure, and no action. The predominant pathways for human exposure to chemical and/or radioactive constituents are through surface, subsurface, and atmospheric transport. Modeling calculations were made to determine the risks to human population via these general pathways for the three postulated closure options. An ecological assessment was conducted to predict the environmental impacts on aquatic and terrestrial biota. The relative costs for each of the closure options were estimated. Evaluation indicates that the relative human health risks for all closure options are small. The greatest public risk would occur after the waste site was released to unrestricted public use (assumed to occur in Year 2085) via the groundwater pathway to a well. The cost estimates show that the waste removal and closure option is the most expensive (89.6 million dollars). The cost of the no waste removal and the no action options is $800,000. 35 refs., 26 figs., 47 tabs

Failure Investigation of Radiant Platen Superheater Tube of Thermal Power Plant Boiler

Science.gov (United States)

Ghosh, D.; Ray, S.; Mandal, A.; Roy, H.

2015-04-01

This paper highlights a case study of typical premature failure of a radiant platen superheater tube of 210 MW thermal power plant boiler. Visual examination, dimensional measurement and chemical analysis, are conducted as part of the investigations. Apart from these, metallographic analysis and fractography are also conducted to ascertain the probable cause of failure. Finally it has been concluded that the premature failure of the super heater tube can be attributed to localized creep at high temperature. The corrective actions has also been suggested to avoid this type of failure in near future.

Premature Ovarian Failure and Fertility in Long-Term Survivors of Hodgkin's Lymphoma : A European Organisation for Research and Treatment of Cancer Lymphoma Group and Groupe d'Etude des Lymphomes de l'Adulte Cohort Study

NARCIS (Netherlands)

van der Kaaij, Marleen A. E.; Heutte, Natacha; Meijnders, Paul; Abeilard-Lemoisson, Edwige; Spina, Michele; Moser, Elizabeth C.; Allgeier, Anouk; Meulemans, Bart; Simons, Arnold H. M.; Lugtenburg, Pieternella J.; Aleman, Berthe M. P.; Noordijk, Evert M.; Ferme, Christophe; Thomas, Jose; Stamatoullas, Aspasia; Fruchart, Christophe; Brice, Pauline; Gaillard, Isabelle; Bologna, Serge; Ong, Francisca; Eghbali, Houchingue; Doorduijn, Jeanette K.; Morschhauser, Franck; Sebban, Catherine; Roesink, Judith M.; Bouteloup, Marie; Van Hoof, Achiel; Raemaekers, John M. M.; Henry-Amar, Michel; Kluin-Nelemans, Hanneke C.

2012-01-01

Purpose In this large cohort of Hodgkin's lymphoma survivors with long follow-up, we estimated the impact of treatment regimens on premature ovarian failure (POF) occurrence and motherhood, including safety of nonalkylating chemotherapy and dose-response relationships for alkylating chemotherapy and

MicroRNA-22-3p is down-regulated in the plasma of Han Chinese patients with premature ovarian failure.

Science.gov (United States)

Dang, Yujie; Zhao, Shidou; Qin, Yingying; Han, Ting; Li, Weiping; Chen, Zi-Jiang

2015-03-01

To determine whether plasma microRNAs (miRNAs) are differentially expressed between women with and without premature ovarian failure (POF), and to uncover the association of miRNAs with risk of POF. Microarray with real-time polymerase chain reaction validation. University hospital. A total of 140 individuals with premature ovarian failure (POF) and 140 age- and body mass index-matched control subjects of Han Chinese ancestry. None. Relative miRNA expression levels in plasma of POF and control group. Fifty-one differentially expressed miRNAs were identified by chip-based discovery stage between ten patients with POF and ten control subjects, among which nine miRNAs (let-7b-5p, let-7c, miR-15b-5p, miR-22-3p, miR-23a-3p, miR-23b-3p, miR-24-3p, miR-151a-5p, and miR-151b) were selected and validated. The relative expression level of miR-22-3p was significantly down-regulated in POF compared with control subjects. MiR-22-3p yielded a receiver operating characteristic (ROC) curve area of 0.668 (95% confidence interval 0.602-0.733) in discriminating POF from controls. In addition, logistic binary regression analysis and linear regression analysis showed the miR-22-3p to be a protective factor for POF (odds ratio 0.766, 95% CI 0.643-0.912) and negatively associated with serum FSH. Furthermore, bioinformatics analysis indicated that the target function of miR-22-3p was involved in apoptosis, endocytosis, and tumorigenesis. Mir-22-3p showed a lower expression level in POF and was modestly effective in distinguishing POF from control subjects. The decreased expression of miR-22-3p in plasma of POF may reflect the diminished ovarian reserve and be a consequence of the pathologic process of POF. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Design Concepts for an Outage Control Center Information Dashboard

International Nuclear Information System (INIS)

Hugo, Jacques Victor; St Germain, Shawn Walter; Thompson, Cheradan Jo; Whitesides, McKenzie Jo; Farris, Ronald Keith

2015-01-01

The nuclear industry, and the business world in general, is facing a rapidly increasing amount of data to be dealt with on a daily basis. In the last two decades, the steady improvement of data storage devices and means to create and collect data along the way influenced the manner in which we deal with information. Most data is still stored without filtering and refinement for later use. Many functions at a nuclear power plant generate vast amounts of data, with scheduled and unscheduled outages being a prime example of a source of some of the most complex data sets at the plant. To make matters worse, modern information and communications technology is making it possible to collect and store data faster than our ability to use it for making decisions. However, in most applications, especially outages, raw data has no value in itself; instead, managers, engineers and other specialists want to extract the information contained in it. The complexity and sheer volume of data could lead to information overload, resulting in getting lost in data that may be irrelevant to the task at hand, processed in an inappropriate way, or presented in an ineffective way. To prevent information overload, many data sources are ignored so production opportunities are lost because utilities lack the ability to deal with the enormous data volumes properly. Decision-makers are often confronted with large amounts of disparate, conflicting and dynamic information, which are available from multiple heterogeneous sources. Information and communication technologies alone will not solve this problem. Utilities need effective methods to exploit and use the hidden opportunities and knowledge residing in unexplored data resources. Superior performance before, during and after outages depends upon the right information being available at the right time to the right people. Acquisition of raw data is the easy part; instead, it is the ability to use advanced analytical, data processing and data

Design Concepts for an Outage Control Center Information Dashboard

Energy Technology Data Exchange (ETDEWEB)

Hugo, Jacques Victor [Idaho National Lab. (INL), Idaho Falls, ID (United States); St Germain, Shawn Walter [Idaho National Lab. (INL), Idaho Falls, ID (United States); Thompson, Cheradan Jo [Idaho National Lab. (INL), Idaho Falls, ID (United States); Whitesides, McKenzie Jo [Idaho National Lab. (INL), Idaho Falls, ID (United States); Farris, Ronald Keith [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-12-01

The nuclear industry, and the business world in general, is facing a rapidly increasing amount of data to be dealt with on a daily basis. In the last two decades, the steady improvement of data storage devices and means to create and collect data along the way influenced the manner in which we deal with information. Most data is still stored without filtering and refinement for later use. Many functions at a nuclear power plant generate vast amounts of data, with scheduled and unscheduled outages being a prime example of a source of some of the most complex data sets at the plant. To make matters worse, modern information and communications technology is making it possible to collect and store data faster than our ability to use it for making decisions. However, in most applications, especially outages, raw data has no value in itself; instead, managers, engineers and other specialists want to extract the information contained in it. The complexity and sheer volume of data could lead to information overload, resulting in getting lost in data that may be irrelevant to the task at hand, processed in an inappropriate way, or presented in an ineffective way. To prevent information overload, many data sources are ignored so production opportunities are lost because utilities lack the ability to deal with the enormous data volumes properly. Decision-makers are often confronted with large amounts of disparate, conflicting and dynamic information, which are available from multiple heterogeneous sources. Information and communication technologies alone will not solve this problem. Utilities need effective methods to exploit and use the hidden opportunities and knowledge residing in unexplored data resources. Superior performance before, during and after outages depends upon the right information being available at the right time to the right people. Acquisition of raw data is the easy part; instead, it is the ability to use advanced analytical, data processing and data

Patients with 47, XXX karyotype who experienced premature ovarian failure (POF): two case reports.

Science.gov (United States)

Sugawara, Nobuo; Maeda, Machiko; Manome, Tomomi; Nagai, Rie; Araki, Yasuhisa

2013-10-01

Pubertal onset and sexual development are usually normal in 47, XXX individuals; however, we report two cases of premature ovarian failure (POF) in infertile women with trisomy X. Chromosome analysis was conducted with G-banding and fluorescence in situ hybridization using X- and Y-bearing probe. Hormonal administration was primarily Kaufmann's treatment or long-term estradiol treatment, followed by withdrawal bleeding from estrogen and progesterone. Two patients with trisomy X, aged 31 (patient 1) and 27 years (patient 2), were diagnosed with POF due to hypergonadotropic hypogonadism. Their ovaries were small. Patient 1 had a FSH level of 44.6 mIU/ml and patient 2 had a FSH level of 74.6 mIU/ml. In patient 1, with Kaufmann's treatment, the FSH decreased to 13.5 mIU/ml; however, follicle growth did not occur following HMG stimulation. In patient 2, FSH did not decrease despite Kaufmann's treatment; therefore, she was given a GnRH agonist and her FSH level decreased to 7.1 mIU/ml. However, her ovaries never responded to HMG stimulation. We report on two patients with a 47, XXX karyotype who became infertile due to POF. We recommend that when a patient is diagnosed with trisomy X, the possibility of POF must be strongly considered.

Vibrational fatigue failures in short cantilevered piping with socket-welding fittings

International Nuclear Information System (INIS)

Smith, J.K.

1996-01-01

Approximately 80% of the vibrational fatigue failures in nuclear power plants have been caused by high cycle vibrational fatigue. Many of these failures have occurred in short, small bore (2 in. nominal diameter and smaller), unbraced, cantilevered piping with socket-welding fittings. The fatigue failures initiated in the socket welds. These failures have been unexpected, and have caused costly, unscheduled outages in some cases. In order to reduce the number of vibrational fatigue failures in these short cantilevered pipes, an acceleration based vibrational fatigue screening criteria was developed under Electric Power Research Institute (EPRI) sponsorship. In this paper, the acceleration based criteria will be compared to the results obtained from detailed dynamic modeling of a short, cantilevered pipe

Consequences of long-term power outages and high electricity prices lasting for months

International Nuclear Information System (INIS)

2005-01-01

Several areas in the world have experienced electricity outages for longer periods of time, but the consequences of these are sparsely documented. There is a need for further analysis of the socioeconomic consequences of the outages. In addition to KILE (Quality adjusted revenue framework for un supplied energy) costs one has to take into account that the costs often increase proportionally with the durance of the outage, and that KILE tariffs do not reflect lost consumer's surplus for products that are not produced during an outage. A good example is the public underground transport, where the company's economical loss can be significantly smaller than the loss of utility value for the travellers. If the authorities act with reasonability it is difficult to see that periods with very high prices represent a big problem. The most important problems are related to diffused effects, especially for households with a weak economy. These problems can be solved with improved contractual forms (price guarantees) or by transfers to the households, without weakening the incentives for electricity economising (ml)

Outage Probability Analysis of FSO Links over Foggy Channel

KAUST Repository

Esmail, Maged Abdullah

2017-02-22

Outdoor Free space optic (FSO) communication systems are sensitive to atmospheric impairments such as turbulence and fog, in addition to being subject to pointing errors. Fog is particularly severe because it induces an attenuation that may vary from few dBs up to few hundreds of dBs per kilometer. Pointing errors also distort the link alignment and cause signal fading. In this paper, we investigate and analyze the FSO systems performance under fog conditions and pointing errors in terms of outage probability. We then study the impact of several effective communication mitigation techniques that can improve the system performance including multi-hop, transmit laser selection (TLS) and hybrid RF/FSO transmission. Closed-form expressions for the outage probability are derived and practical and comprehensive numerical examples are suggested to assess the obtained results. We found that the FSO system has limited performance that prevents applying FSO in wireless microcells that have a 500 m minimum cell radius. The performance degrades more when pointing errors appear. Increasing the transmitted power can improve the performance under light to moderate fog. However, under thick and dense fog the improvement is negligible. Using mitigation techniques can play a major role in improving the range and outage probability.

Outage Probability Analysis of FSO Links over Foggy Channel

KAUST Repository

Esmail, Maged Abdullah; Fathallah, Habib; Alouini, Mohamed-Slim

2017-01-01

Outdoor Free space optic (FSO) communication systems are sensitive to atmospheric impairments such as turbulence and fog, in addition to being subject to pointing errors. Fog is particularly severe because it induces an attenuation that may vary from few dBs up to few hundreds of dBs per kilometer. Pointing errors also distort the link alignment and cause signal fading. In this paper, we investigate and analyze the FSO systems performance under fog conditions and pointing errors in terms of outage probability. We then study the impact of several effective communication mitigation techniques that can improve the system performance including multi-hop, transmit laser selection (TLS) and hybrid RF/FSO transmission. Closed-form expressions for the outage probability are derived and practical and comprehensive numerical examples are suggested to assess the obtained results. We found that the FSO system has limited performance that prevents applying FSO in wireless microcells that have a 500 m minimum cell radius. The performance degrades more when pointing errors appear. Increasing the transmitted power can improve the performance under light to moderate fog. However, under thick and dense fog the improvement is negligible. Using mitigation techniques can play a major role in improving the range and outage probability.

Performance Shaping Factors Assessments and Application to PHWR Outages

Energy Technology Data Exchange (ETDEWEB)

Lee, Seung Woo

2007-02-15

Human reliability analysis is definitely related to the quality of PSA because human errors have been identified as major contributors to PSA. According to NRC's 'Office of analysis and evaluation of operational data (AEOD)',82% of the reactor trips and accident during outage is caused by the events related to human errors. There is, however, no one HRA method universally accepted. Furthermore, HRA during PHWR outages has not been performed around the world yet. HRA during PHWR outages is especially important since manual management of operator is more required during PHWR. In this study, accident scenarios which HYU developed are used to perform a quantification of human error probability. In this study, overall procedures of standard HRA methodology are introduced and follows the quantification of 10 possible selected human actions during PHWR outages based on standard HRA methodology. To see the verification, quantified values were compared with the values from 'Generic CANDU Probabilistic Safety Assessment' and the values estimated by ASEP.Core Damage Frequency was estimated 3.35 x 10{sup -4} more higher than CDF estimated by AECL data. It was considered that the differences between the HEPs for OPAFW and OPECC3 make CDF higher. Therefore, complementary study of reestimating HEP for OPAFW and OPECC3 in detail is required for increasing the qualities of HRA and PSA. Moreover, one of the difficulties in performing human reliability analysis is to evaluate performance shaping factors which represent the characteristics and circumstances. For assessing a specific human action more exactly, it is necessary to consider all of the PSFs at the same time which makes an effect on the human action. Also, it requires the effect comparison among PSFs to minimize the uncertainties which are usually caused by the subjective judgements of HRA analysts. To see the sensitivity, performance shaping factors of each decision rule are changed which resulted

Performance Shaping Factors Assessments and Application to PHWR Outages

International Nuclear Information System (INIS)

Lee, Seung Woo

2007-02-01

Human reliability analysis is definitely related to the quality of PSA because human errors have been identified as major contributors to PSA. According to NRC's 'Office of analysis and evaluation of operational data (AEOD)',82% of the reactor trips and accident during outage is caused by the events related to human errors. There is, however, no one HRA method universally accepted. Furthermore, HRA during PHWR outages has not been performed around the world yet. HRA during PHWR outages is especially important since manual management of operator is more required during PHWR. In this study, accident scenarios which HYU developed are used to perform a quantification of human error probability. In this study, overall procedures of standard HRA methodology are introduced and follows the quantification of 10 possible selected human actions during PHWR outages based on standard HRA methodology. To see the verification, quantified values were compared with the values from 'Generic CANDU Probabilistic Safety Assessment' and the values estimated by ASEP.Core Damage Frequency was estimated 3.35 x 10 -4 more higher than CDF estimated by AECL data. It was considered that the differences between the HEPs for OPAFW and OPECC3 make CDF higher. Therefore, complementary study of reestimating HEP for OPAFW and OPECC3 in detail is required for increasing the qualities of HRA and PSA. Moreover, one of the difficulties in performing human reliability analysis is to evaluate performance shaping factors which represent the characteristics and circumstances. For assessing a specific human action more exactly, it is necessary to consider all of the PSFs at the same time which makes an effect on the human action. Also, it requires the effect comparison among PSFs to minimize the uncertainties which are usually caused by the subjective judgements of HRA analysts. To see the sensitivity, performance shaping factors of each decision rule are changed which resulted in changes of core damage

Programming and organisation of unit outages

International Nuclear Information System (INIS)

Hadjidakis, Y.; Cezard, C.; Audierne, J.

1997-01-01

The unit outages are scheduled every 12 to 18 months for fuel reloading. The success of these shutdowns, with the whole of objectives (duration, dosimetry, costs), with maintaining the safety level, is an important stake for the competitiveness of the enterprise. In this article are described the planning, the experience return and the organisation of scheduled shutdowns which have contribute to the improvement of availability. (N.C.)

Exact Outage Probability of Dual-Hop CSI-Assisted AF Relaying Over Nakagami-m Fading Channels

KAUST Repository

Xia, Minghua; Aissa, Sonia; Wu, Yik-Chung

2012-01-01

to evaluate the outage performance of the system under study. The analytical results of outage probability coincide exactly with Monte-Carlo simulation results and outperform the previously reported upper bounds in the low and medium SNR regions.

Synergistic Use of Nighttime Satellite Data, Electric Utility Infrastructure, and Ambient Population to Improve Power Outage Detections in Urban Areas

Directory of Open Access Journals (Sweden)

Tony A. Cole

2017-03-01

Full Text Available Natural and anthropogenic hazards are frequently responsible for disaster events, leading to damaged physical infrastructure, which can result in loss of electrical power for affected locations. Remotely-sensed, nighttime satellite imagery from the Suomi National Polar-orbiting Partnership (Suomi-NPP Visible Infrared Imaging Radiometer Suite (VIIRS Day/Night Band (DNB can monitor power outages in disaster-affected areas through the identification of missing city lights. When combined with locally-relevant geospatial information, these observations can be used to estimate power outages, defined as geographic locations requiring manual intervention to restore power. In this study, we produced a power outage product based on Suomi-NPP VIIRS DNB observations to estimate power outages following Hurricane Sandy in 2012. This product, combined with known power outage data and ambient population estimates, was then used to predict power outages in a layered, feedforward neural network model. We believe this is the first attempt to synergistically combine such data sources to quantitatively estimate power outages. The VIIRS DNB power outage product was able to identify initial loss of light following Hurricane Sandy, as well as the gradual restoration of electrical power. The neural network model predicted power outages with reasonable spatial accuracy, achieving Pearson coefficients (r between 0.48 and 0.58 across all folds. Our results show promise for producing a continental United States (CONUS- or global-scale power outage monitoring network using satellite imagery and locally-relevant geospatial data.

OPG's approach of crediting natural circulation in outage heat sinks

International Nuclear Information System (INIS)

Fung, K.K.; Mackinnon, J.C.

2001-01-01

A review of crediting natural circulation as a backup means of removing the reactor core decay heat during an outage in Ontario Power Generation's nuclear stations was completed in 2000. The objective was to define the configurations and conditions under which natural circulation can be confidently credited as an effective heat transport mechanism for use in shutdown heat sink management. The project was an interdisciplinary program, and involved analyses in the areas of heat transport system thermalhydaulics, fuel and fuel channel thermal and mechanical behaviour, radiation physics, and probabilistic risks. The assessment shows that it is economically acceptable to credit natural circulation as a backup means of removing the core decay heat whenever the no fuel failure criteria are met. The economic risks associated with such a potential use decrease with time after shutdown. The waiting times after shutdown when there would be various levels of risks of damaging the pressure tubes and fuel bundles were derived for use in planning maintenance activities so as to minimize the economic risks. (author)

Study on optimization of normal plant outage work plan for nuclear power plants

International Nuclear Information System (INIS)

Aoki, Takayuki; Kodama, Noriko; Takase, Kentaro; Miya, Kenzo

2011-01-01

This paper discusses maintenance optimization in maintenance implementation stage following maintenance planning stage in nuclear power plants and proposes a methodology to get an optimum maintenance work plan. As a result of consideration, the followings were obtained. (1) The quantitative evaluation methodology for optimizing maintenance work plan in nuclear power plants was developed. (2) Utilizing the above methodology, a simulation analysis of maintenance work planning for BWR's PLR and RHR systems in a normal plant outage was performed. Maintenance cost calculation in several cases was carried out on the condition of smoothening man loading over the plant outage schedule as much as possible. (3) As a result of the simulation, the economical work plans having a flat man loading over the plant outage schedule were obtained. (author)

Prevention and reversal of intestinal failure-associated liver disease in premature infants with short bowel syndrome using intravenous fish oil in combination with omega-6/9 lipid emulsions.

Science.gov (United States)

Lilja, Helene Engstrand; Finkel, Yigael; Paulsson, Mattias; Lucas, Steven

2011-07-01

Although premature infants with short bowel syndrome are at the highest risk of developing intestinal failure-associated liver disease (IFALD), they have great capacity for intestinal growth and adaptation if IFALD can be prevented. Conventional soybean oil-based intravenous lipid emulsions have been associated with IFALD. This study presents data on 5 premature neonates with short bowel syndrome treated with a combination of parenteral fish oil- and olive/soybean-based lipid emulsion for periods ranging between 7 and 17 months. Despite an enteral tolerance of less than 50% in 4 of these patients during their first year of life, direct bilirubin levels normalized while on this combination of ClinOleic (Baxter, Maurepas, France)/Omegaven (Fresenius Kabi, Bad Homburg, Germany) at a 1:1 ratio. None of our patients developed irreversible IFALD even though all of them were premature, had undergone multiple major surgical procedures, and had experienced several episodes of sepsis. Thus far, we have not seen any adverse effects of this mixed lipid emulsion in these preterm infants. All 5 patients are growing and developing well and have normal liver function. Copyright © 2011 Elsevier Inc. All rights reserved.

Kozloduy NPP units 5 and 6 modernization program. Measures implementation in outages

International Nuclear Information System (INIS)

Naydenov, N.; Mignone, O.

2004-01-01

The units 5 and 6 modernization program is a highly demanding program composed by many plant modifications and studies about plant conditions. The program measures implementation during the units outages represents a challenge by the need to compromise shut down duration with the workload related to measures installation. The units shutdown duration should be kept to the planned duration. In parallel, contractors work has to be organized, planned and performed to allow successful measures completion. In accordance with the contract requirements, contractors prepare installation documents which comprise all activities to be performed during the installation and testing of the measures. The subcontractors complement these installation documents with the project organization and execution documents, which include the manpower skills, qualifications, work orders, and other important installation instructions and information. Contractors prepared detailed installation schedules, and these were integrated by Parsons E and C in the Integrated installation schedule. The integrated schedule proved to be useful to identify possible area usage conflicts and manpower overlapping, with appropriate results for electrical, instrumentation and control work, and for the utilization of the polar crane in the containment building. Contractors installation schedules were updated on a weekly basis, showing variances versus the target, and manpower histograms for the resource loading. Organization of contractors work was supported by KNPP plant outage meetings, in which status and problems were addressed, and solution and/or corrective actions defined for further implementation. KNPP meetings were planned on a daily basis for most relevant or critical measures, or on a weekly basis for less intensive measures. KNPP meetings proved to be an excellent communication tool for keeping the measures under control and monitoring KNPP defined personnel responsible for authorizing changes, in

The course of a true outage never ran so smooth

International Nuclear Information System (INIS)

Harberts, Craig

1994-01-01

In order to improve the performance of outages at San Onofre Nuclear Generating Station in California, the working structure of the entire organisation has had to be radically altered, in order to bring San Onofre up to standard with other nuclear plants known to be performing well. Working systems were simplified and efficiency improved. Personnel needed to be remotivated to work cooperatively and the outage budget process was revised to include input from all relevant organizations, historical costs and benchmark information from other plants that performed well. Finally, the decision making and teamwork culture has altered radically at San Onofre over the last decade. (UK)

Myopia in premature babies with and without retinopathy of prematurity.

OpenAIRE

Nissenkorn, I; Yassur, Y; Mashkowski, D; Sherf, I; Ben-Sira, I

1983-01-01

One hundred and fifty-five premature infants weighing 600-2000 g were followed up during 1974-80 for the presence of retinopathy of prematurity (ROP) and for the existence of myopia. 50% of the premature infants who had ROP were myopic, while only 16% myopic premature infants were found among those who did not have ROP. There was a positive correlation between the degree of myopia and the severity of cicatricial ROP. No difference existed in the frequency and degree of myopia between prematur...

Outage Analysis of Asymmetric RF-FSO Systems

KAUST Repository

Ansari, Imran Shafique

2017-03-20

In this work, the outage performance analysis of a dual-hop transmission system composed of asymmetric radio frequency (RF) channels cascaded with free-space optical (FSO) links is presented. The RF links are modeled by the Rayleigh fading distribution and the FSO links are modeled by Malaga (M) turbulence distribution. The FSO links account for pointing errors and both types of detection techniques (i.e. heterodyne detection as well as intensity modulation/direct detection (IM/DD)). Transmit diversity is applied at the source, selection combining is applied at the destination, and the relay is equipped with single RF receive antenna and single aperture for relaying the information over FSO links. With this model, a new exact closed-form expression is derived for the outage probability of the end-to- end signal-to-noise ratio of such communication systems in terms of the Meijer\\'s G function under fixed amplify-and-forward relay scheme. All new analytical results are verified via computer-based Monte-Carlo simulations and are illustrated by some selected numerical results.

Verification and Enhancement of VIIRS Day-Night Band (DNB) Power Outage Detection Product

Science.gov (United States)

Burke, Angela; Schultz, Lori A.; Omitaomu, Olufemi; Molthan, Andrew L.; Cole, Tony; Griffin, Robert

2017-01-01

This case study of Hurricane Matthew (October 2016) uses the NASA Short-Term Prediction Research and Transition (SPoRT) Center DNB power outage product (using GSFC VIIRS DNB preliminary Black Marble product, Roman et al.. 2017) and 2013 LandScan Global population data to look for correlations between the post-event %-of-normal radiance and the utility company-reported outage numbers (obtained from EAGLE-1).

Retinopathy of prematurity and neurodevelopmental disabilities in premature infants.

Science.gov (United States)

Beligere, Nagamani; Perumalswamy, Vijayalaksmi; Tandon, Manish; Mittal, Amit; Floora, Jayasheele; Vijayakumar, B; Miller, Marilyn T

2015-10-01

Prematurity is a major global health issue leading to high mortality and morbidity among the survivors. Neurodevelopmental disability (NDD) and retinopathy of prematurity (ROP) are the most common complications of prematurity. In fact, ROP is the second leading cause of childhood blindness in the world. Although there is much information regarding the occurrence of ROP and of NDD in premature infants, there have been few studies on ROP and its association with NDD. The objectives of this article are to review the current literature on the subject and to publish our own findings concerning the association between ROP and NDD in premature infants. The review suggests that although NDDs are related to degree of prematurity, NDD could also be the result of visual impairments resulting from ROP. Our own study shows a close association between NDD and zonal involvement of ROP: higher NDD if zone 1 is involved and less if zone 3 is involved. Copyright © 2015 Elsevier Ltd. All rights reserved.

Economic costs of electrical system instability and power outages caused by snakes on the Island of Guam

Science.gov (United States)

Fritts, T.H.

2002-01-01

The Brown Tree Snake, Boiga irregularis, is an introduced species on Guam where it causes frequent electrical power outages. The snake's high abundance, its propensity for climbing, and use of disturbed habitats all contribute to interruption of Guam's electrical service and the activities that depend on electrical power. Snakes have caused more than 1600 power outages in the 20-yr period of 1978–1997 and most recently nearly 200 outages per year. Single outages spanning the entire island and lasting 8 or more hours are estimated to cost in excess of $3,000,000 in lost productivity, but the costs of outages that involve only parts of the island or those of shorter durations are more difficult to quantify. Costs to the island's economy have exceeded $4.5 M $4.5M"> per year over a 7-yr period without considering repair costs, damage to electrical equipment, and lost revenues. Snakes pose the greatest problem on high voltage transmission lines, on transformers, and inside electrical substations.

Psychosocial work strain of maintenance personnel during annual outage and normal operation in a nuclear power plant

International Nuclear Information System (INIS)

Jacobsson, L.; Svensson, O.

1991-01-01

This paper reports on a study which evaluates psychosocial work demands during the annual outage for a maintenance work group in a nuclear power plant. The study is based on a stress paradigm and it has been asserted that increased work strain would have a negative effect on performance. Nineteen workers, aged 20-55 years, participated in the study. The subjects filled out a questionnaire comparing work strain during annual outage and normal operation. During the outage period a 3-shift 24-hour work schedule, including nightwork, was used (working hours during normal operation was 7-16). Increased demands on concentration and vigilance, increased time pressure and strain on social relations within the group were found to characterize work during annual outage. Interestingly, for specific work tasks an association was found between the risk of making errors and high psychological workload. Increased work strain, shiftwork including nightwork and reduced social support are important psychosocial risk factors that might contribute to human error during the outage period

A Study of the Impact of Peak Demand on Increasing Vulnerability of Cascading Failures to Extreme Contingency Events

Energy Technology Data Exchange (ETDEWEB)

Vyakaranam, Bharat GNVSR; Vallem, Mallikarjuna R.; Nguyen, Tony B.; Samaan, Nader A.; Berscheid, Alan P.; Makarov, Yuri V.; Diao, Ruisheng

2017-10-02

The vulnerability of large power systems to cascading failures and major blackouts has become evident since the Northeast blackout in 1965. Based on analyses of the series of cascading blackouts in the past decade, the research community realized the urgent need to develop better methods, tools, and practices for performing cascading-outage analysis and for evaluating mitigations that are easily accessible by utility planning engineers. PNNL has developed the Dynamic Contingency Analysis Tool (DCAT) as an open-platform and publicly available methodology to help develop applications that aim to improve the capabilities of power planning engineers to assess the impact and likelihood of extreme contingencies and potential cascading events across their systems and interconnections. DCAT analysis will help identify potential vulnerabilities and allow study of mitigation solutions to reduce the risk of cascading outages in technically sound and effective ways. Using the DCAT capability, we examined the impacts of various load conditions to identify situations in which the power grid may encounter cascading outages that could lead to potential blackouts. This paper describes the usefulness of the DCAT tool and how it helps to understand potential impacts of load demand on cascading failures on the power system.

Proceedings of a joint OECD/NEA-IAEA symposium on human factors and organisation in NPP maintenance outages: impact on safety

International Nuclear Information System (INIS)

1995-01-01

The sessions of this conference dealt with outage strategy and methods (in Sweden, France and United States), the organisation and management of outages (organisation during refuelling shutdowns in France, safety approaches in France, in the USA, in Canada, in the United Kingdom and in Sweden), case studies and lessons learned (in France, Korea, Sweden, UK, USA), regulatory aspects of outages (UK, Germany, Mexico, France), the development of outage techniques

The role of domoic acid in abortion and premature parturition of California sea lions (Zalophus californianus) on San Miguel Island, California.

Science.gov (United States)

Goldstein, Tracey; Zabka, Tanja S; Delong, Robert L; Wheeler, Elizabeth A; Ylitalo, Gina; Bargu, Sibel; Silver, Mary; Leighfield, Tod; Van Dolah, Frances; Langlois, Gregg; Sidor, Inga; Dunn, J Lawrence; Gulland, Frances M D

2009-01-01

Domoic acid is a glutaminergic neurotoxin produced by marine algae such as Pseudo-nitzschia australis. California sea lions (Zalophus californianus) ingest the toxin when foraging on planktivorous fish. Adult females comprise 60% of stranded animals admitted for rehabilitation due to acute domoic acid toxicosis and commonly suffer from reproductive failure, including abortions and premature live births. Domoic acid has been shown to cross the placenta exposing the fetus to the toxin. To determine whether domoic acid was playing a role in reproductive failure in sea lion rookeries, 67 aborted and live-born premature pups were sampled on San Miguel Island in 2005 and 2006 to investigate the causes for reproductive failure. Analyses included domoic acid, contaminant and infectious disease testing, and histologic examination. Pseudo-nitzschia spp. were present both in the environment and in sea lion feces, and domoic acid was detected in the sea lion feces and in 17% of pup samples tested. Histopathologic findings included systemic and localized inflammation and bacterial infections of amniotic origin, placental abruption, and brain edema. The primary lesion in five animals with measurable domoic acid concentrations was brain edema, a common finding and, in some cases, the only lesion observed in aborted premature pups born to domoic acid-intoxicated females in rehabilitation. Blubber organochlorine concentrations were lower than those measured previously in premature sea lion pups collected in the 1970s. While the etiology of abortion and premature parturition was varied in this study, these results suggest that domoic acid contributes to reproductive failure on California sea lion rookeries.

Methodology if inspections to carry out the nuclear outages model

International Nuclear Information System (INIS)

Aycart, J.; Mortenson, S.; Fourquet, J. M.

2005-01-01

Before the nuclear generation industry was deregulated in the United States, refueling and maintenance outages in nuclear power plants usually lasted orotund 100 days. After deregulation took effect, improved capability factors and performances became more important. As a result, it became essential to reduce the critical path time during the outage, which meant that activities that had typically been done in series had to be executed in parallel. The new outage model required the development of new tools and new processes, The 360-degree platform developed by GE Energy has made it possible to execute multiple activities in parallel. Various in-vessel visual inspection (IVVI) equipments can now simultaneously perform inspections on the pressurized reactor vessel (RPV) components. The larger number of inspection equipments in turn results in a larger volume of data, with the risk of increasing the time needed for examining them and postponing the end of the analysis phase, which is critical for the outage. To decrease data analysis times, the IVVI Digitalisation process has been development. With this process, the IVVI data are sent via a high-speed transmission line to a site outside the Plant called Center of Excellence (COE), where a team of Level III experts is in charge of analyzing them. The tools for the different product lines are being developed to interfere with each other as little as possible, thus minimizing the impact of the critical path on plant refueling activities. Methods are also being developed to increase the intervals between inspection. In accordance with the guidelines of the Boiling Water Reactor Vessel and Internals project (BWRVIP), the intervals between inspections are typically longer if ultrasound volumetric inspections are performed than if the scope is limited to IVVI. (Author)

Oocyte cryopreservation for fertility preservation in postpubertal female children at risk for premature ovarian failure due to accelerated follicle loss in Turner syndrome or cancer treatments.

Science.gov (United States)

Oktay, K; Bedoschi, G

2014-12-01

To preliminarily study the feasibility of oocyte cryopreservation in postpubertal girls aged between 13 and 15 years who were at risk for premature ovarian failure due to the accelerated follicle loss associated with Turner syndrome or cancer treatments. Retrospective cohort and review of literature. Academic fertility preservation unit. Three girls diagnosed with Turner syndrome, 1 girl diagnosed with germ-cell tumor. and 1 girl diagnosed with lymphoblastic leukemia. Assessment of ovarian reserve, ovarian stimulation, oocyte retrieval, in vitro maturation, and mature oocyte cryopreservation. Response to ovarian stimulation, number of mature oocytes cryopreserved and complications, if any. Mean anti-müllerian hormone, baseline follical stimulating hormone, estradiol, and antral follicle counts were 1.30 ± 0.39, 6.08 ± 2.63, 41.39 ± 24.68, 8.0 ± 3.2; respectively. In Turner girls the ovarian reserve assessment indicated already diminished ovarian reserve. Ovarian stimulation and oocyte cryopreservation was successfully performed in all female children referred for fertility preservation. A range of 4-11 mature oocytes (mean 8.1 ± 3.4) was cryopreserved without any complications. All girls tolerated the procedure well. Oocyte cryopreservation is a feasible technique in selected female children at risk for premature ovarian failure. Further studies would be beneficial to test the success of oocyte cryopreservation in young girls. Copyright © 2014 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

Impact of Co-Channel Interference on the Outage Performance Under Multiple Type II Relay Environments

KAUST Repository

Choi, Seyeong; Alouini, Mohamed-Slim; Nam, Sung Sik

2017-01-01

In this paper, through an exact analysis of the outage probability, we investigate the impact of co-channel interference (CCI) on the outage performance of type II (or user equipment) relay under multiple-relay environments considering the selection combining-based relay selection scheme with the decode-and-forward protocol. We consider the signal to interference plus noise ratio (SINR) over both independent and identically distributed and independent but non-identically distributed fading channels. To fully take into account the effect of CCI, we adopt a more practical parameter such as the CCI coefficient. The major difficulty in the analysis resides in the determination of the statistics of the output SINR. To settle this problem, we first present the general but relatively simplified expressions for the statistics and then the related outage probability in closed-form. Furthermore, to consider more practical scenario, based on the fact that the number of participating relays can be random, we investigate the average outage probability by averaging the number of participating relays.

Impact of Co-Channel Interference on the Outage Performance Under Multiple Type II Relay Environments

KAUST Repository

Choi, Seyeong

2017-11-15

In this paper, through an exact analysis of the outage probability, we investigate the impact of co-channel interference (CCI) on the outage performance of type II (or user equipment) relay under multiple-relay environments considering the selection combining-based relay selection scheme with the decode-and-forward protocol. We consider the signal to interference plus noise ratio (SINR) over both independent and identically distributed and independent but non-identically distributed fading channels. To fully take into account the effect of CCI, we adopt a more practical parameter such as the CCI coefficient. The major difficulty in the analysis resides in the determination of the statistics of the output SINR. To settle this problem, we first present the general but relatively simplified expressions for the statistics and then the related outage probability in closed-form. Furthermore, to consider more practical scenario, based on the fact that the number of participating relays can be random, we investigate the average outage probability by averaging the number of participating relays.

Partner cooperation with decode-and-forward: Closed-form outage analysis and comparison

KAUST Repository

Benjillali, Mustapha

2013-01-01

In this paper, we investigate the outage performance of "partner cooperation" based on opportunistic Decodeand- Forward with constrained partial selection and reactive relaying strategies in dual-hop cooperative Nakagami-m fading links. The source/destination, which is based on the unique knowledge of local channel state information, selects the best relay to increase the chances of cooperation in both uplink and downlink communications when the direct link is also available. After deriving new expressions for the cumulative distribution functions of the variables of interest, the outage probability of the system is obtained in closed-form. We also derive the ε-outage capacity in different particular cases, and the obtained results - when the channel model is reduced to a Rayleigh fading - either are new or correspond to those previously obtained in other works. Simulation results confirm the accuracy of our analysis for a large selection of system and fading parameters and provide a new insight into the design and optimization of cooperative configurations. © 2012 IEEE.

Improvement of availability of PWR nuclear plants through the reduction of the time required for refueling/maintenance outages

International Nuclear Information System (INIS)

Mayers, J.B.; Soth, L.G.

1978-04-01

The objective of the project, conducted by Commonwealth Research Corporation and Westinghouse Electric Corporation, is to identify improvements in procedures and equipment which will reduce the time required for refueling/maintenance outages at PWR nuclear power plants. The outage of Commonwealth Edison Zion Station Unit 1 in March through May of 1976 was evaluated to identify those items which caused delays and those work activities that offer the potential for significant improvements that could reduce the overall duration of the outage and achieve an improvement in the plant's availability for power production. Modifications in procedures have been developed and were evaluated during one or more outages in 1977. Conceptual designs have been developed for equipment modifications to the refueling system that could reduce the time required for the refueling portion of the outage. The purpose of the interim report is to describe those conceptual designs and to assess their impact upon future outages. Recommendations are included for the implementation of these equipment improvements in a continuation of this program as a demonstration of plant availability benefits that can be realized in PWR nuclear plants already in operation or under construction

Outage Analysis and Optimization of SWIPT in Network-Coded Two-Way Relay Networks

Directory of Open Access Journals (Sweden)

Ruihong Jiang

2017-01-01

Full Text Available This paper investigates the outage performance of simultaneous wireless information and power transfer (SWIPT in network-coded two-way relay systems, where a relay first harvests energy from the signals transmitted by two sources and then uses the harvested energy to forward the received information to the two sources. We consider two transmission protocols, power splitting two-way relay (PS-TWR and time switching two-way relay (TS-TWR protocols. We present two explicit expressions for the system outage probability of the two protocols and further derive approximate expressions for them in high and low SNR cases. To explore the system performance limits, two optimization problems are formulated to minimize the system outage probability. Since the problems are nonconvex and have no known solution methods, a genetic algorithm- (GA- based algorithm is designed. Numerical and simulation results validate our theoretical analysis. It is shown that, by jointly optimizing the time assignment and SWIPT receiver parameters, a great performance gain can be achieved for both PS-TWR and TS-TWR. Moreover, the optimized PS-TWR always outperforms the optimized TS-TWR in terms of outage performance. Additionally, the effects of parameters including relay location and transmit powers are also discussed, which provide some insights for the SWIPT-enabled two-way relay networks.

Outage Performance of Decode-and-Forward in Two-Way Relaying with Outdated CSI

KAUST Repository

Hyadi, Amal

2015-01-07

In this paper, we analyze the outage behavior of decode-and-forward relaying in the context of selective two-way cooperative systems. First, a new relay selection metric is proposed to take into consideration both transmission rates and instantaneous link conditions between cooperating nodes. Afterwards, the outage probability of the proposed system is derived for Nakagami-m fading channels in the case when perfect channel state information is available and then extended to the more realistic scenario where the available channel state information (CSI) is outdated due to fast fading. New expressions for the outage probability are obtained, and the impact of imperfect CSI on the performance is evaluated. Illustrative numerical results, Monte Carlo simulations, and comparisons with similar approaches are presented to assess the accuracy of our analytical derivations and confirm the performance gain of the proposed scheme.

Your Premature Baby

Science.gov (United States)

... volunteer leader Partner Spotlight Become a partner World Prematurity Day What's happening in your area Find out ... 3 weeks after a premature birth. Retinopathy of prematurity (ROP) . This is an abnormal growth of blood ...

Management of planned unit outages

International Nuclear Information System (INIS)

Brune, W.

1984-01-01

Management of planned unit outages at the Bruno Leuschner Nuclear Power Plant is based on the experience gained with Soviet PWR units of the WWER type over a period of more than 50 reactor-years. For PWR units, planned outages concentrate almost exclusively on annual refuellings and major maintenance of the power plant facilities involved. Planning of such major maintenance work is based on a standardized basic network plan and a catalogue of standardized maintenance and inspection measures. From these, an overall maintenance schedule of the unit and partial process plans of the individual main components are derived (manually or by computer) and, in the temporal integration of major maintenance at every unit, fixed starting times and durations are determined. More than 75% of the maintenance work at the Bruno Leuschner Nuclear Power Plant is carried out by the plant's own maintenance personnel. Large-scale maintenance of every unit is controlled by a special project head. He is assisted by commissioners, each of whom is responsible for his own respective item. A daily control report is made. The organizational centre is a central office which works in shifts around the clock. All maintenance orders and reports of completion pass through this office; thus, the overall maintenance schedule can be corrected daily. To enforce the proposed operational strategy, suitable accompanying technical measures are required with respect to effective facility monitoring and technical diagnosis, purposeful improvement of particularly sensitive components and an increase in the effectiveness of maintenance work by special technologies and devices. (author)

Control Room Tasks During Refueling in Ringhals 1 Nuclear Power Plant - Operator performance during refuelling outages

International Nuclear Information System (INIS)

Stroebeck, Einar; Olausson, Jesper; Van Gemst, Paul

1998-01-01

This paper discusses the performance and tasks of the operators in the control room during refuelling outages. Analyses of such events have, during the last years, shown that the risk for nuclear accidents is not negligible compared with the risk at higher reactor power levels. Some experts have the opinion that, due to mistakes during an outage, the risk for such accidents during the outage and other accidents later on during power operation is higher than in other plant situations. The high risk level is mainly a result of errors at maintenance actions and supervision of lining up of safety systems. Most of the control rooms in existing NPPs were designed more than 10 years ago. At that time the activities and the tasks for the operators were not very well understood. Procedures for refuelling and other activities during the outages were not described very well. Often the utility organisation for refuelling outages was not established at the start of the control room design. Experience from operation during many years has shown that the performance of operators can be improved in existing plant, and thus risks be reduced, by upgrading the control room. These issues have been studied as a part of the modernisation project for Ringhals 1, an ABB Atom BWR owned by Vattenfall AB in Sweden. The paper will describe the working model for upgrading the control room and important issues to take care of with respect to refuelling outages. The identified issues will be used as the input for improving control room philosophy and the individual technical systems. (authors)

Integrated head area design of KNGR to reduce refueling outage duration

Energy Technology Data Exchange (ETDEWEB)

Jeong, Woo Tae; Park, Chi Yong; Kim, In Hwan; Kim, Dae Woong [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

1998-12-31

In the design of KNGR (Korea Next Generation Reactor), we believe that economy is one of the most important factors to be considered. Thus, we reviewed and evaluated the consequences of designing the head area into an integrated package from an economical point of view. The refueling outage durations of the nuclear power plants currently in operation in Korea, some having and others not having integrated head package, are compared. This paper discusses the characteristics of head area design and the critical design issues of KNGR head area to evaluate the effect of the head area characteristics on the outage duration. 8 refs., 4 figs. (Author)

Integrated head area design of KNGR to reduce refueling outage duration

Energy Technology Data Exchange (ETDEWEB)

Jeong, Woo Tae; Park, Chi Yong; Kim, In Hwan; Kim, Dae Woong [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

1997-12-31

In the design of KNGR (Korea Next Generation Reactor), we believe that economy is one of the most important factors to be considered. Thus, we reviewed and evaluated the consequences of designing the head area into an integrated package from an economical point of view. The refueling outage durations of the nuclear power plants currently in operation in Korea, some having and others not having integrated head package, are compared. This paper discusses the characteristics of head area design and the critical design issues of KNGR head area to evaluate the effect of the head area characteristics on the outage duration. 8 refs., 4 figs. (Author)

Failure Analysis of High-Power Piezoelectric Transducers

National Research Council Canada - National Science Library

Gabrielson, T. B

2005-01-01

... and stress in a piezoelectric material. For a transducer operated near resonance, there will be "hot spots" or regions of locally intense stress and electric field that precipitate premature failure...

A novel fusion methodology to bridge GPS outages for land vehicle positioning

International Nuclear Information System (INIS)

Chen, Wei; Li, Xu; Song, Xiang; Xu, Qimin; Li, Bin; Song, Xianghui

2015-01-01

Many intelligent transportation system applications require accurate, reliable, and continuous vehicle position information whether in open-sky environments or in Global Positioning System (GPS) denied environments. However, there remains a challenging task for land vehicles to achieve such positioning performance using low-cost sensors, especially microelectromechanical system (MEMS) sensors. In this paper, a novel and cost-effective fusion methodology to bridge GPS outages is proposed and applied in the Inertial Navigation System (INS)/GPS/ compass integrated positioning system. In the implementation of the proposed methodology, a key data preprocessing algorithm is first developed to eliminate the noise in inertial sensors in order to provide more accurate information for subsequent modeling. Then, a novel hybrid strategy incorporating the designed autoregressive model (AR model)-based forward estimator (ARFE) with Kalman filter (KF) is presented to predict the INS position errors during GPS outages. To verify the feasibility and effectiveness of the proposed methodology, real road tests with various scenarios were performed. The proposed methodology illustrates significant improvement in positioning accuracy during GPS outages. (paper)

Investigation into Cause of High Temperature Failure of Boiler Superheater Tube

Science.gov (United States)

Ghosh, D.; Ray, S.; Roy, H.; Shukla, A. K.

2015-04-01

The failure of the boiler tubes occur due to various reasons like creep, fatigue, corrosion and erosion. This paper highlights a case study of typical premature failure of a final superheater tube of 210 MW thermal power plant boiler. Visual examination, dimensional measurement, chemical analysis, oxide scale thickness measurement, microstructural examination are conducted as part of the investigations. Apart from these investigations, sulfur print, Energy Dispersive spectroscopy (EDS) and X ray diffraction analysis (XRD) are also conducted to ascertain the probable cause of failure of final super heater tube. Finally it has been concluded that the premature failure of the super heater tube can be attributed to the combination of localized high tube metal temperature and loss of metal from the outer surface due to high temperature corrosion. The corrective actions have also been suggested to avoid this type of failure in near future.

Refueling outage services in Spanish Nuclear Power Plants

International Nuclear Information System (INIS)

Landete, J. L.; Soto, M.; Nunuez, A.

2007-01-01

DOMINGUIS Group, through its 75 years of business development, has positioned as the Spanish leader Group in Services for the Nuclear Energy and Petrochemical Sectors. In this article, we present the most significant services summary that, through the companies that constitute DOMINGUIS Group, we have developed in Refueling Outage in Spanish Nuclear Power Plants. (Author)

A study on assessment methodology of surveillance test interval and Allowed Outage Time

Energy Technology Data Exchange (ETDEWEB)

Che, Moo Seong; Cheong, Chang Hyeon; Ryu, Yeong Woo; Cho, Jae Seon; Heo, Chang Wook; Kim, Do Hyeong; Kim, Joo Yeol; Kim, Yun Ik; Yang, Hei Chang [Seoul National Univ., Seoul (Korea, Republic of)

1997-07-15

Objectives of this study is the development of methodology by which assesses the optimization of Surveillance Test Interval(STI) and Allowed Outage Time(AOT) using PSA method that can supplement the current deterministic methods and the improvement of Korean nuclear power plants safety. In the first year of this study, the survey about the assessment methodologies, modeling and results performed by domestic and international researches are performed as the basic step before developing the assessment methodology of this study. The assessment methodology that supplement the revealed problems in many other studies is presented and the application of new methodology into the example system assures the feasibility of this method. In the second year of this study, the sensitivity analyses about the failure factors of the components are performed in the bases of the assessment methodologies of the first study, the interaction modeling of the STI and AOT is quantified. And the reliability assessment methodology about the diesel generator is reviewed and applied to the PSA code.

A study on assessment methodology of surveillance test interval and Allowed Outage Time

International Nuclear Information System (INIS)

Che, Moo Seong; Cheong, Chang Hyeon; Ryu, Yeong Woo; Cho, Jae Seon; Heo, Chang Wook; Kim, Do Hyeong; Kim, Joo Yeol; Kim, Yun Ik; Yang, Hei Chang

1997-07-01

Objectives of this study is the development of methodology by which assesses the optimization of Surveillance Test Interval(STI) and Allowed Outage Time(AOT) using PSA method that can supplement the current deterministic methods and the improvement of Korean nuclear power plants safety. In the first year of this study, the survey about the assessment methodologies, modeling and results performed by domestic and international researches are performed as the basic step before developing the assessment methodology of this study. The assessment methodology that supplement the revealed problems in many other studies is presented and the application of new methodology into the example system assures the feasibility of this method. In the second year of this study, the sensitivity analyses about the failure factors of the components are performed in the bases of the assessment methodologies of the first study, the interaction modeling of the STI and AOT is quantified. And the reliability assessment methodology about the diesel generator is reviewed and applied to the PSA code

A study on assessment methodology of surveillance test interval and allowed outage time

Energy Technology Data Exchange (ETDEWEB)

Chung, Chang Hyun; You, Young Woo; Cho, Jae Seon; Huh, Chang Wook; Kim, Do Hyoung; Kim, Ju Youl; Kim, Yoon Ik; Yang, Hui Chang; Park, Kang Min [Seoul National Univ., Seoul (Korea, Republic of)

1998-03-15

The objectives of this study is the development of methodology by which assesses the optimization of Surveillance Test Internal(STI) and Allowed Outage Time(AOT) using PSA method that can supplement the current deterministic methods and the improvement of Korean nuclear power plant safety. In this study, the survey about the assessment methodologies, modelings and results performed by domestic and international researches are performed as the basic step before developing the assessment methodology of this study. The assessment methodology that supplement the revealed problems in many other studies is presented and the application of new methodology into the example system assures the feasibility of this method. The sensitivity analyses about the failure factors of the components are performed in the bases of the and AOT is quantified. And the reliability assessment methodology about the diesel generator is reviewed and applied to the PSA code. The qualitative assessment for the STI/AOR of RPS/ESFAS assured safety the most important system in the nuclear power plant are performed.

Outage performance of Decode-and-Forward partial selection in Nakagami-m fading channels

KAUST Repository

Benjillali, Mustapha

2010-01-01

In this paper, we investigate the outage performance of Decode-and-Forward with partial selection relaying in dualhop cooperative Nakagami-m fading links. The source, based on the unique knowledge of local first hop channel state information, selects the best relay to increase the chances of successful decoding and hence the possibility of cooperation when the direct link is also available. After deriving the exact distribution of the sum of two gamma variates with the same shape parameter, the outage probability of the system-with and without the direct link-is obtained in closed-form. We also derive the ε-outage capacity in different particular cases, and the obtained results- when the channel model is reduced to a Rayleigh fading-are either new or correspond to those previously obtained in other works. Simulation results confirm the accuracy of our analysis for a large selection of system and fading parameters. © 2009 IEEE.

Shortened outage duration and increased safety with head assembly upgrade packages

International Nuclear Information System (INIS)

Leanne, M.; Lisien, P.E.; Plute, K.; Duran, J.

2007-01-01

To significantly reduce outage critical path duration and personnel radiation exposure, and to increase personnel safety, Westinghouse Electric Co., LLC has designed and installed upgrades to the existing head assemblies of operating pressurized water reactors. These upgrades are known as Head Assembly Upgrade Packages (HAUPs) or Simplified Head Assemblies (SHAs). Custom configurations are created from a set of standard elements to optimize the design for each unique containment, head assembly configuration, and licensing basis. Two primary options are available for implementation: a full HAUP or targeted component and system upgrades. Plants may achieve much of the outage savings, dose reduction, and safety improvements even with a more limited hardware scope. A range of improvements can be offered from integral missile shields, to redesigned duct work, radiation shields, and cable layout and connection optimization. The hardware changes are customized to target the scope that adds the most value for a given plant. While combining upgrades with a reactor vessel head (RVH) replacement adds some flexibility, it is not necessary. Some plants have chosen to implement targeted upgrades prior to a replacement RVH outage and then complete the remainder of the full HAUP during the replacement RVH outage. Three-dimensional computer aided design tools are used in the conceptual and detailed design phases to identify and avoid interferences between existing and replacement plant components. State-of-the-art computational fluid dynamics models for control drive mechanism (CDM) cooling systems are used to demonstrate the ability to maintain or improve the original design performance while greatly simplifying the disassembly/re-assembly activities. Likewise, state-of-the-art finite element analysis methods allow optimization of structural components while meeting code limits for design basis accident conditions. (authors)

Power Allocation and Outage Probability Analysis for SDN-based Radio Access Networks

Science.gov (United States)

Zhao, Yongxu; Chen, Yueyun; Mai, Zhiyuan

2018-01-01

In this paper, performance of Access network Architecture based SDN (Software Defined Network) is analyzed with respect to the power allocation issue. A power allocation scheme PSO-PA (Particle Swarm Optimization-power allocation) algorithm is proposed, the proposed scheme is subjected to constant total power with the objective of minimizing system outage probability. The entire access network resource configuration is controlled by the SDN controller, then it sends the optimized power distribution factor to the base station source node (SN) and the relay node (RN). Simulation results show that the proposed scheme reduces the system outage probability at a low complexity.

Thermal Hydraulic Assessment for Loss of SDCS Event During the Outage of CANDU Reactor

Energy Technology Data Exchange (ETDEWEB)

Kim, Jonghyun [Gnest, Inc. Taejon (Korea, Republic of); Lee, Kwangho; Oh, Haechol; Jun, Hwangyong [KEPRI, Taejon (Korea, Republic of)

2006-07-01

During the outage(overhaul) of the nuclear power plant, there are several operating states other than the full power state, that is 'Hot-Zero Power', 'Depressurized-Cooldown', and 'Partially Drained'. Until now safety assessment has not been done much for this operating state of CANDU type reactor worldwide. For the accuracy and confidence of PSA for the CANDU outage, the safety analysis is necessary. At the first stage, we analyzed the thermal hydraulic characteristics and safety of the postulated event of loss of shutdown cooling system (SDCS) during the partially drained state which is the longest one in the middle of outage period. As an analysis tool, this study uses the best estimate thermal hydraulic code, RELAP5/CANDU which was modified according to the CANDU specific characteristics and based on RELAP5.Mod3.

Outage planning in nuclear power plants. A paradigm shift from an external towards an integrated project planning tool

Energy Technology Data Exchange (ETDEWEB)

Rosemann, Andreas [Gesellschaft fuer integrierte Systemplanung (GiS) mbH, Weinheim (Germany)

2014-05-15

In nuclear power plants it is common to carry out the technical planning of the annual outage work orders in an Enterprise Application Management (EAM) system and to schedule the outage tasks in a project planning tool. The reason for this is historical: Former EAM systems did not (or just to some extend) offer the necessary functionalities to realise the scheduling of the outage; graphical support for the planning was not provided at all. Consequently, scheduling the annual outage was performed in a separate planning tool. Modern Enterprise Application Management (EAM) software builds on established project planning tools with respect to the functionalities and timing of work orders. As a standard they provide editable charts as well as a lot of functionalities which are required for scheduling the annual outage. The functional gap between the demanded planning functionalities and the functionalities provided by the EAM system has been significantly reduced. Depending on the deployed software itself it is possible to extend the EAM system with little effort (in comparison to the promising advantages) so that external project timing planning tools are not required any more. By shifting towards an integrated planning tool, efficiency in planning an outage as well as the quality of communication of the current planning status increases. Furthermore, the basis of information for work orders by the control room staff and therefore safety can be enhanced. (orig.)

Outage planning in nuclear power plants. A paradigm shift from an external towards an integrated project planning tool

International Nuclear Information System (INIS)

Rosemann, Andreas

2014-01-01

In nuclear power plants it is common to carry out the technical planning of the annual outage work orders in an Enterprise Application Management (EAM) system and to schedule the outage tasks in a project planning tool. The reason for this is historical: Former EAM systems did not (or just to some extend) offer the necessary functionalities to realise the scheduling of the outage; graphical support for the planning was not provided at all. Consequently, scheduling the annual outage was performed in a separate planning tool. Modern Enterprise Application Management (EAM) software builds on established project planning tools with respect to the functionalities and timing of work orders. As a standard they provide editable charts as well as a lot of functionalities which are required for scheduling the annual outage. The functional gap between the demanded planning functionalities and the functionalities provided by the EAM system has been significantly reduced. Depending on the deployed software itself it is possible to extend the EAM system with little effort (in comparison to the promising advantages) so that external project timing planning tools are not required any more. By shifting towards an integrated planning tool, efficiency in planning an outage as well as the quality of communication of the current planning status increases. Furthermore, the basis of information for work orders by the control room staff and therefore safety can be enhanced. (orig.)

Outage performance of opportunistic two-way amplify-and-forward relaying with outdated channel state information

KAUST Repository

Hwang, Kyusung

2013-09-01

In this paper, we study the outage performance of an amplify-and-forward (AF)-based two-way relaying (TWR) system with multiple relays where a single relay selection is performed based on outdated channel state information (CSI). Specifically, we propose a single relay selection scheme in AF-based TWR system under outdated CSI conditions. With this policy, we offer a statistical analysis of the signal-to-noise ratio per hop and analyze the outage probability with asymmetric outage thresholds based on CSI-assisted AF protocol. Additionally, we provide the exact and asymptotic expressions based on the provided statistical/joint statistical analyses of a dual-hop AF transmission. Finally, we verify our analytical results with some selected computer-based simulation results. © 1972-2012 IEEE.

Statistical evaluation of failures and repairs of the V-1 measuring and control system

International Nuclear Information System (INIS)

Laurinec, R.; Korec, J.; Mitosinka, J.; Zarnovican, V.

1984-01-01

A failure record card system was introduced for evaluating the reliability of the measurement and control equipment of the V-1 nuclear power plant. The SPU-800 microcomputer system is used for recording data on magnetic tape and their transmission to the central data processing department. The data are used for evaluating the reliability of components and circuits and a selection is made of the most failure-prone components, and the causes of failures are evaluated as are failure identification, repair and causes of outages. The system provides monthly, annual and total assessment data since the system was commissioned. The results of the statistical evaluation of failures are used for planning preventive maintenance and for determining optimal repair intervals. (E.S.)

Retinopathy of Prematurity

Science.gov (United States)

Steinweg, Sue Byrd; Griffin, Harold C.; Griffin, Linda W.; Gingras, Happy

2005-01-01

The eyes of premature infants are especially vulnerable to injury after birth. A serious complication is called retinopathy of prematurity (ROP), which is abnormal growth of the blood vessels in an infant's eye. Retinopathy of prematurity develops when abnormal blood vessels grow and spread throughout the retina, which is the nerve tissue at the…

Outage performance of reactive cooperation in Nakagami-m fading channels

KAUST Repository

Benjillali, Mustapha; Alouini, Mohamed-Slim

2010-01-01

In this paper, we investigate the outage performance of Decode-and-Forward with reactive relaying in dual-hop cooperetive Nakagaml-m fading links. The destination, based on the umque knowledge of local second hop channel state information, selects

Outage performance of cognitive radio systems with Improper Gaussian signaling

KAUST Repository

Amin, Osama; Abediseid, Walid; Alouini, Mohamed-Slim

2015-01-01

design the SU signal by adjusting its transmitted power and the circularity coefficient to minimize the SU outage probability while maintaining a certain PU quality-of-service. Finally, we evaluate the proposed bounds and adaptive algorithms by numerical

A Study on the Frequency of Initiating Event of OPR-1000 during Outage Periods

Energy Technology Data Exchange (ETDEWEB)

Hong Jae Beol; Jae, Moo Sung [Hanyang Univ., Seoul (Korea, Republic of)

2013-10-15

These sources of data did not reflect the latest event data which have occurred during the PWR outage to the frequencies of initiating event Electric Power Research Institute(EPRI) in USA collected the data of loss of decay heat removal during outage from 1989 to 2009 and published technical report. Domestic operating experiences for LOOP is gathered in Operational Performance Information System for Nuclear Power Plant(OPIS). To reduce conservatism and obtain completeness for LPSD PSA, those data should be collected and used to update the frequencies. The frequencies of LOSDC and LOOP are reevaluated using the data of EPRI and OPIS in this paper. Quantification is conducted to recalculate core damage frequency(CDF), since the rate is changed. The results are discussed below. To make an accurate estimate of the initiating events of LPSD PSA, the event data were collected and the frequencies of initiating events were updated using Bayesian approach. CDF was evaluated through quantification. Δ CDF is -40% and the dominant contributor is pressurizer PSV stuck open event. The most of the event data in EPRI TR were collected from US nuclear power plant industry. Those data are not enough to evaluate outage risk precisely. Therefore, to reduce conservatism and obtain completeness for LPSD PSA, the licensee event report and domestic data should be collected and reflected to the frequencies of the initiating events during outage.

10 CFR 501.191 - Use of natural gas or petroleum for certain unanticipated equipment outages and emergencies...

Science.gov (United States)

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Use of natural gas or petroleum for certain unanticipated... Natural Gas or Petroleum for Emergency and Unanticipated Equipment Outage Purposes § 501.191 Use of natural gas or petroleum for certain unanticipated equipment outages and emergencies defined in section...

Outage Probability Analysis in Power-Beacon Assisted Energy Harvesting Cognitive Relay Wireless Networks

Directory of Open Access Journals (Sweden)

Ngoc Phuc Le

2017-01-01

Full Text Available We study the performance of the secondary relay system in a power-beacon (PB assisted energy harvesting cognitive relay wireless network. In our system model, a secondary source node and a relay node first harvest energy from distributed PBs. Then, the source node transmits its data to the destination node with the help of the relay node. Also, fading coefficients of the links from the PBs to the source node and relay node are assumed independent but not necessarily identically distributed (i.n.i.d Nakagami-m random variables. We derive exact expressions for the power outage probability and the channel outage probability. Based on that, we analyze the total outage probability of the secondary relay system. Asymptotic analysis is also performed, which provides insights into the system behavior. Moreover, we evaluate impacts of the primary network on the performance of the secondary network with respect to the tolerant interference threshold at the primary receiver as well as the interference introduced by the primary transmitter at the secondary source and relay nodes. Simulation results are provided to validate the analysis.

A heuristic model for risk and cost impacts of plant outage maintenance schedule

International Nuclear Information System (INIS)

Mohammad Hadi Hadavi, S.

2009-01-01

Cost and risk are two major competing criteria in maintenance optimization problems. If a plant is forced to shutdown because of accident or fear of accident happening, beside loss of revenue, it causes damage to the credibility and reputation of the business operation. In this paper a heuristic model for incorporating three compelling optimization criteria (i.e., risk, cost, and loss) into a single evaluation function is proposed. Such a model could be used in any evaluation engine of outage maintenance schedule optimizer. It is attempted to make the model realistic and to address the ongoing challenges facing a schedule planner in a simple and commonly understandable fashion. Two simple competing schedules for the NPP feedwater system are examined against the model. The results show that while the model successfully addresses the current challenges for outage maintenance optimization, it properly demonstrates the dynamics of schedule in regards to risk, cost, and losses endured by maintenance schedule, particularly when prolonged outage and lack of maintenance for equipments in need of urgent care are of concern.

Evaluation of allowed outage time using PRA results

International Nuclear Information System (INIS)

Johanson, G.

1985-01-01

In a probabilistic risk assessment (PRA) different measures of risk importance can be established. These measures can be used as a basis for further evaluation and determination of allowed outage time for specific components, within safety systems of a nuclear power plant. In order to optimize the allowed outage time (AOT) stipulated in the plant's Technical Specification it is necessary to create a methodology which could incorporate existing PRA data into a quantitative extrapolation. In order to evaluate the plant risk status due to AOT in a quantitative manner, the risk achievement worth is utilized. Risk achievement worth is defined as follows: to measure the worth of a feature, in achieving the present risk, one approach is to remove the feature and then determine how much the risk has increased. Thus, the risk achievement worth is formally defined to be the increase in risk if the feature were assumed not be there or to be failed. Another parameter of interest for this analysis is the shutdown risk increase. The shutdown risk achievement worth must be incorporated into the accident sequence risk achievement worth to arrive at an optimal set of plant specific AOTs

ISS Ammonia Pump Failure, Recovery, and Lesson Learned A Hydrodynamic Bearing Perspective

Science.gov (United States)

Bruckner, Robert J.; Manco, Richard A., II

2014-01-01

The design, development, and operation of long duration spaceflight hardware has become an evolutionary process in which meticulous attention to details and lessons learned from previous experiences play a critical role. Invaluable to this process is the ability to retrieve and examine spaceflight hardware that has experienced a premature failure. While these situations are rare and unfortunate, the failure investigation and recovery from the event serve a valuable purpose in advancing future space mechanism development. Such a scenario began on July 31, 2010 with the premature failure of an ammonia pump on the external active thermal control system of the International Space Station. The ground-based inspections of the returned pump and ensuing failure investigation revealed five potential bearing forces that were un-accounted for in the design phase and qualification testing of the pump. These forces could combine in a number of random orientations to overload the pump bearings leading to solid-surface contact, wear, and premature failure. The recovery plan identified one of these five forces as being related to the square of the operating speed of the pump and this fact was used to recover design life through a change in flight rules for the operation of the pump module. Through the course of the failure investigation, recovery, and follow-on assessment of pump wear life, design guidance has been developed to improve the life of future mechanically pumped thermal control systems for both human and robotic exploration missions.

Lessons learned in planning ALARA/health physics support for major nuclear power plant outages

International Nuclear Information System (INIS)

Gilman, T.R.; Lesinski, M.L.

1987-01-01

Although as low as reasonably achievable (ALARA)/health physics is viewed as necessary support for nuclear power plant outage work, it can be the last area to which attention is given in preparing for a large-scope outage. Inadequate lead times cause last-minute preparations resulting in delays in planned work. The Dresden Unit 3 Recirculation Piping Replacement Project is examined from a planning viewpoint. The attention that was given the various areas of a comprehensive ALARA/health physics program is examined, and approximate recommended lead times are discussed. The discussion will follow a chronological path from project inception to the beginning stages of outage work. Initially, the scope of work needs to be assessed by individuals familiar with similar projects of equivalent magnitude. Those individuals need to be health physics professionals who understand the particular utility and/or the site's way of doing business. They should also possess a good understanding of preferred industry practices

Study on European Nuclear Safety Practices during Planned Outages at Nuclear Power Plants

International Nuclear Information System (INIS)

2001-12-01

The present project was aimed at providing: a description of the current status of nuclear safety practices during planned outages at nuclear power plants followed in Europe; the criteria for the safety analysis of future reactors at the design stage; proposing a set of recommendations on good practices and criteria leading to the improvement of nuclear safety during those conditions. The work was organised in 3 phases: Collecting data on current practices; Analysis of questionnaire answers and drawing up of safety good practices references and recommendations; Collecting relevant ideas related to the future reactors at design stage (European Pressurised Water Reactor, European Passive Plant project, European Utilities Requirements and Utilities Requirement Document project). The key element of the performed work was the detailed questionnaire, based on bibliographical review, expert experience and outage practices available in the working team. Different safety areas and activities were covered: outage context; nuclear safety; outage strategy, organisation and control; operating feedback; use of Probabilistic Safety Assessment. The questionnaire was answered by 12 European nuclear power plants, representing 9 different European countries and three different types of reactors (Pressurised Water Reactor, Boiling Water Reactor and Water Water Energy Reactor). Conclusions were drawn under the following headers: Organisational survey and generalities Organisational effectiveness Quality of maintenance Quality of operation Engineering support, management of modification Specific aspects Each analysed subject includes the following topics: Questions background with a summary and the aim of the questions. Current status, that describes common practices, as derived from the answers to the questionnaire, and some examples of good specific practices. Identified good practices. (author)

Early or Premature Menopause

Science.gov (United States)

... email updates Enter email Submit Early or premature menopause Menopause that happens before age 40 is called ... What is the difference between early and premature menopause? Early or premature menopause happens when ovaries stop ...

Premature ovarian insufficiency: Pathogenesis and management

Directory of Open Access Journals (Sweden)

Anna J Fenton

2015-01-01

Full Text Available The term premature ovarian insufficiency (POI describes a continuum of declining ovarian function in a young woman, resulting in an earlier than average menopause. It is a term that reflects the variable nature of the condition and is substantially less emotive than the formerly used "premature ovarian failure" which signaled a single event in time. Contrary to the decline in the age of menarche seen over the last 3-4 decades there has been no similar change in the age of menopause. In developed nations, the average age for cessation of menstrual cycles is 50-52 years. The age is younger among women from developing nations. Much has been written about POI despite a lack of good data on the incidence of this condition. It is believed that 1% of women under the age of 40 years and 0.1% under the age of 30 years will develop POI. Research is increasingly providing information about the pathogenesis and treatments are being developed to better preserve ovarian function during cancer treatment and to improve fertility options. This narrative review summarizes the current literature to provide an approach to best practice management of POI.

Outage probability of dual-hop partial relay selection with feedback delay in the presence of interference

KAUST Repository

Al-Qahtani, Fawaz S.

2011-09-01

In this paper, we investigate the outage performance of a dual-hop relaying systems with partial relay selection and feedback delay. The analysis considers the case of Rayleigh fading channels when the relaying station as well as the destination undergo mutually independent interfering signals. Particularly, we derive the cumulative distribution function (c.d.f.) of a new type of random variable involving sum of multiple independent exponential random variables, based on which, we present closed-form expressions for the exact outage probability of a fixed amplify-and-forward (AF) and decode-and-forward (DF) relaying protocols. Numerical results are provided to illustrate the joint effect of the delayed feedback and co-channel interference on the outage probability. © 2011 IEEE.

Siemens capabilities to perform detailed fuel inspections during short outages

International Nuclear Information System (INIS)

Knecht, K.; Reparaz, A.

1999-01-01

Fuel inspection data are used to support development activities such as corrosion resistant cladding and advanced fuel assembly designs that will reach higher burnups. Increased inspection efforts are necessary to optimize fuel management and performance strategies. Additionally, there is an increasing trend to reduce outage time in Germany and abroad. Siemens has recently developed several timesaving systems for rapid inspection of fuel assemblies and core components. Siemens' focus in developing these systems has been to obtain data in reduced reactor outage time while increasing both the volume and the quality of the measured data. Mast sipping for PWRs is used for identifying leaking fuel assemblies and allows early detection of leaks during downloading of the fuel assemblies from the reactor. An In-Core sipping system for BWRs based on a hood technique to allow testing a full core within 16 hours is under development. (authors)

Outage planning in nuclear power plants. A paradigm shift from an external towards an integrated project planning tool

Energy Technology Data Exchange (ETDEWEB)

Rosemann, Andreas [Gesellschaft fuer integrierte Systemplanung (GIS) mbH, Weinheim (Germany)

2014-07-01

Latest demands on nuclear plant inspections are the ongoing actualisation of the outage plan on the basis of the current work progress and current events as well as the permanent access to the current planning status and work process of all people involved in the outage. Modern EAM systems (EAM: Enterprise Application Management) made up ground on established project planning tools with regard to functionalities for scheduling work orders. A shift towards an integrated planning in the EAM system increases the efficiency in the outage planning and improves the communication of current states of planning. (orig.)

Outage planning in nuclear power plants. A paradigm shift from an external towards an integrated project planning tool

International Nuclear Information System (INIS)

Rosemann, Andreas

2014-01-01

Latest demands on nuclear plant inspections are the ongoing actualisation of the outage plan on the basis of the current work progress and current events as well as the permanent access to the current planning status and work process of all people involved in the outage. Modern EAM systems (EAM: Enterprise Application Management) made up ground on established project planning tools with regard to functionalities for scheduling work orders. A shift towards an integrated planning in the EAM system increases the efficiency in the outage planning and improves the communication of current states of planning. (orig.)

Lower early postnatal oxygen saturation target and risk of ductus arteriosus closure failure.

Science.gov (United States)

Inomata, Kei; Taniguchi, Shinji; Yonemoto, Hiroki; Inoue, Takeshi; Kawase, Akihiko; Kondo, Yuichi

2016-11-01

Early postnatal hyperoxia is a major risk factor for retinopathy of prematurity (ROP) in extremely premature infants. To reduce the occurrence of ROP, we adopted a lower early postnatal oxygen saturation (SpO 2 ) target range (85-92%) from April 2011. Lower SpO 2 target range, however, may lead to hypoxemia and an increase in the risk of ductus arteriosus (DA) closure failure. The aim of this study was therefore to determine whether a lower SpO 2 target range, during the early postnatal stage, increases the risk of DA closure failure. Infants born at closure failure in period 2 (21%) was significantly higher than that in period 1 (1%). On multivariate logistic regression analysis, the lower oxygen saturation target range was an independent risk factor for DA closure failure. Lower early postnatal oxygen saturation target range increases the risk of DA closure failure. © 2016 Japan Pediatric Society.

Outage probability analysis of a secondary user in an underlay dual hop cognitive amplify and forward relay network

Directory of Open Access Journals (Sweden)

Kiran Chandra

2016-09-01

Full Text Available This paper presents the performance evaluation of a secondary user (SU in an underlay cognitive dual-hop relaying system considering instantaneous as well as average channel information of the interfering links (from the secondary source and relay to the primary receiver and the data link from the secondary source to relay, to calculate transmit power and amplifying gain of secondary system. Comparison of above mentioned cases is done for two different scenarios – with direct path and without direct path. We evaluate the performance considering two different diversity techniques namely as selection combining (SC and maximum ratio combining (MRC. The effect of different fading channels (Rayleigh and Nakagami on the outage performance of the SU for the two diversity techniques is also shown. The outage probability of the SU is reduced when the diversity techniques are used (with direct path as compared to the outage probability of SU without direct path. We find that the outage performance is better for instantaneous channel information as compared to average channel information for the links. We observe that MRC provides better performance than SC. Furthermore, this work shows that the outage performance of the SU has been improved when the Nakagami fading channel (m = 2 is considered instead of Rayleigh fading channel.

Pharmacotherapy for premature ejaculation

NARCIS (Netherlands)

Waldinger, Marcel D

2014-01-01

PURPOSE OF REVIEW: As there are various drugs and different treatment strategies to delay ejaculation, a review of the current drug treatments for premature ejaculation is relevant for daily clinical practice. RECENT FINDINGS: There are four premature ejaculation subtypes: lifelong premature

An analysis of human maintenance failures of a nuclear power plant

International Nuclear Information System (INIS)

Pyy, P.

2000-01-01

In the report, a study of faults caused by maintenance activities is presented. The objective of the study was to draw conclusions on the unplanned effects of maintenance on nuclear power plant safety and system availability. More than 4400 maintenance history reports from the years 1992-1994 of Olkiluoto BWR nuclear power plant (NPP) were analysed together with the maintenance personnel. The human action induced faults were classified, e.g., according to their multiplicity and effects. This paper presents and discusses the results of a statistical analysis of the data. Instrumentation and electrical components appeared to be especially prone to human failures. Many human failures were found in safety related systems. Several failures also remained latent from outages to power operation. However, the safety significance of failures was generally small. Modifications were an important source of multiple human failures. Plant maintenance data is a good source of human reliability data and it should be used more in the future. (orig.)

Efficient Simulation of the Outage Probability of Multihop Systems

KAUST Repository

Ben Issaid, Chaouki; Alouini, Mohamed-Slim; Tempone, Raul

2017-01-01

In this paper, we present an efficient importance sampling estimator for the evaluation of the outage probability of multihop systems with amplify-and-forward channel state-information-assisted. The proposed estimator is endowed with the bounded relative error property. Simulation results show a significant reduction in terms of number of simulation runs compared to naive Monte Carlo.

Efficient Simulation of the Outage Probability of Multihop Systems

KAUST Repository

Ben Issaid, Chaouki

2017-10-23

In this paper, we present an efficient importance sampling estimator for the evaluation of the outage probability of multihop systems with amplify-and-forward channel state-information-assisted. The proposed estimator is endowed with the bounded relative error property. Simulation results show a significant reduction in terms of number of simulation runs compared to naive Monte Carlo.

Science beyond boundary: are premature discoveries things of the past?

Science.gov (United States)

Singh, Rama S

2016-06-01

Mendel's name more than of any other draws our attention to the personal side in terms of success and failure in science. Mendel lived 19 years after presenting his research findings and died without receiving any recognition for his work. Are premature discoveries things of the past, you may ask? I review the material basis of science in terms of science boundary and field accessibility and analyze the possibility of premature discoveries in different fields of science such as, for example, physics and biology. I conclude that science has reached a stage where progress is being made mostly by pushing the boundary of the known from inside than by leaping across boundaries. As more researchers become engaged in science, and as more publications become open access, on-line, and interactive, the probability of an important discovery remaining buried and going unrecognized would become exceedingly small. Of course, as examples from physics show, a new theory or an important idea can always lie low, unrecognized until it becomes re-discovered and popularized by other researchers. Thus, premature discoveries will become less likely but not forbidden.

[Laser treatment for retinopathy of prematurity in neonatal intensive care units. Premature Eye Rescue Program].

Science.gov (United States)

Maka, Erika; Imre, László; Somogyvári, Zsolt; Németh, János

2015-02-01

Retinopathy of prematurity is a leading cause of childhood blindness around the world. The Department of Ophthalmology at the Semmelweis University and the Peter Cerny Neonatal Emergency and Ambulance Service started an innovative Premature Eye Rescue Program to reduce the non-essential transport of premature babies suffering from retinopathy of prematurity. During the first 5 years 186 eyes of 93 premature babies were treated at the bedside with stage 3 retinopathy of prematurity in the primary hospitals. In this first 5-years period the authors reduced the number of transports of premature babies for laser treatment; 93 children avoided the unnecessary transport, saving altogether a distance of 21,930 kilometers for children, as well as the ambulance service. The Premature Eye Rescue Program offers a good and effective alternative for treatment of retinopathy in the primary hospitals. The authors propose the national extension of this program.

Insuring unit failures in electricity markets

International Nuclear Information System (INIS)

Pineda, S.; Conejo, A.J.; Carrion, M.

2010-01-01

An electric energy producer participates in futures markets in the hope of hedging the risk of trading in the pool. However, this producer is required to supply the energy associated with all its signed forward contracts even if some of its units are forced out due to unexpected failures. In this case, the producer must purchase some of the energy needed to meet its futures market commitments in the pool, which may result in high losses if the pool prices happen to be higher than the forward contract prices. To mitigate these losses, the producer can take out insurance against the forced outages of its units. Using a stochastic programming model, this paper analyzes the convenience of signing an insurance against unit failure by an electric energy producer and its impact on forward contracting decisions. Results from a realistic case study are provided and analyzed.

Replacement power costs due to nuclear-plant outages: a higher standard of care

International Nuclear Information System (INIS)

Gransee, M.F.

1982-01-01

This article examines recent state public utility commission cases that deal with the high costs of replacement power that utilities must purchase after a nuclear power plant outage. Although most commissions have approved such expenses, it may be that there is a trend toward splitting the costs of such expenses between ratepayer and stockholder. Commissions are demanding a management prudence test to determine the cause of the outage and whether it meets the reasonable man standard before allowing these costs to be passed along to ratepayers. Unless the standard is applied with flexibility, however, utility companies could invoke the defenses covering traditional common law negligence

Outage performance analysis of underlay cognitive RF and FSO wireless channels

KAUST Repository

Ansari, Imran Shafique; Abdallah, Mohamed M.; Alouini, Mohamed-Slim; Qaraqe, Khalid A.

2014-01-01

In this work, the outage performance analysis of a dual-hop transmission system composed of asymmetric radio frequency (RF) channel cascaded with a free-space optical (FSO) link is presented. For the RF link, an underlay cognitive network

Investigation on cause of outage of Wide Range Monitor (WRM) in High Temperature engineering Test Reactor (HTTR). Transport operation toward investigation for cause of outage

International Nuclear Information System (INIS)

Shinohara, Masanori; Sawahata, Hiroaki; Kawamoto, Taiki; Saito, Kenji; Takada, Shoji; Yoshida, Naoaki; Isozaki, Ryosuke; Katsuyama, Kozo; Motegi, Toshihiro

2012-08-01

An event, in which one of WRMs were disabled to detect the neutron flux in the reactor core, occurred during the period of reactor shut down of HTTR in March, 2010. The actual life time of WRM was unexpectedly shorter than the past developed life time. Investigation of the cause of the outage of WRM toward the recovery of the life time up to the developed life is one of the issues to develop the technology basis of High Temperature Gas cooled Reactor (HTGR). Then, a post irradiation examination was planned to specify the damaged part causing the event in the WRM was also planned. For the investigation, the X-ray computed tomography scanner in Fuels Monitoring Facility (FMF). This report describes the preliminary investigation on the cause of outage of the WRM. The results of study for transportation method of the irradiated WRM from HTTR to FMF is also reported with the record to complete the transport operation. (author)

A RLS-SVM Aided Fusion Methodology for INS during GPS Outages.

Science.gov (United States)

Yao, Yiqing; Xu, Xiaosu

2017-02-24

In order to maintain a relatively high accuracy of navigation performance during global positioning system (GPS) outages, a novel robust least squares support vector machine (LS-SVM)-aided fusion methodology is explored to provide the pseudo-GPS position information for the inertial navigation system (INS). The relationship between the yaw, specific force, velocity, and the position increment is modeled. Rather than share the same weight in the traditional LS-SVM, the proposed algorithm allocates various weights for different data, which makes the system immune to the outliers. Field test data was collected to evaluate the proposed algorithm. The comparison results indicate that the proposed algorithm can effectively provide position corrections for standalone INS during the 300 s GPS outage, which outperforms the traditional LS-SVM method. Historical information is also involved to better represent the vehicle dynamics.

A RLS-SVM Aided Fusion Methodology for INS during GPS Outages

Directory of Open Access Journals (Sweden)

Yiqing Yao

2017-02-01

Full Text Available In order to maintain a relatively high accuracy of navigation performance during global positioning system (GPS outages, a novel robust least squares support vector machine (LS-SVM-aided fusion methodology is explored to provide the pseudo-GPS position information for the inertial navigation system (INS. The relationship between the yaw, specific force, velocity, and the position increment is modeled. Rather than share the same weight in the traditional LS-SVM, the proposed algorithm allocates various weights for different data, which makes the system immune to the outliers. Field test data was collected to evaluate the proposed algorithm. The comparison results indicate that the proposed algorithm can effectively provide position corrections for standalone INS during the 300 s GPS outage, which outperforms the traditional LS-SVM method. Historical information is also involved to better represent the vehicle dynamics.

On the Outage Performance of Full-Duplex Selective Decode-and-Forward Relaying

KAUST Repository

Khafagy, Mohammad Galal

2013-02-25

We evaluate the outage performance in a three-terminal full-duplex relay channel that adopts a selective decode-and-forward protocol, taking relay self-interference into account. Previous work focused on coverage extension scenarios where direct source-destination transmissions are neglected or considered as interference. In this work, we account for the relay self-interference, and exploit the cooperative diversity offered by the independently fading source/relay message replicas that arrive at the destination. We present an approximate, yet accurate, closed-form expression for the end-to-end outage probability that captures their joint effect. With the derived expression in hand, we propose a relay transmit power optimization scheme that only requires the relay knowledge of channel statistics. Finally, we corroborate our analysis with simulations.

Outage Performance of Hybrid FSO/RF System with Low-Complexity Power Adaptation

KAUST Repository

Rakia, Tamer

2016-02-26

Hybrid free-space optical (FSO) / radio-frequency (RF) systems have emerged as a promising solution for high data- rate wireless communication systems. We consider truncated channel inversion based power adaptation strategy for coherent and non- coherent hybrid FSO/RF systems, employing an adaptive combining scheme. Specifically, we activate the RF link along with the FSO link when FSO link quality is unacceptable, and adaptively set RF transmission power to ensure constant combined signal-to-noise ratio at receiver terminal. Analytical expressions for the outage probability of the hybrid system with and without power adaptation are derived. Numerical examples show that, the hybrid FSO/RF systems with power adaptation achieve considerable outage performance improvement over conventional hybrid FSO/RF systems without power adaptation. © 2015 IEEE.

Radio resource management scheme and outage analysis for network-assisted multi-hop D2D communications

Directory of Open Access Journals (Sweden)

Leila Melki

2016-11-01

Full Text Available In a cellular network it's very difficult to make spectrum resource more efficiently. Device-to-Device (D2D technology enables new service opportunities, and provides high throughput and reliable communication while reducing the base station load. For better total performance, short-range D2D links and cellular links share the same radio resource and the management of interference becomes a crucial task. Here we argue that single-hop D2D technology can be used to further improve cellular networks performance if the key D2D radio resource management algorithms are suitably extended to support multi-hop D2D communications. Aiming to establish a new paradigm for the analysis and design of multi-hop D2D communications, We propose a radio resource allocation for multi-hop D2D routes based on interference avoidance approach in LTE-A networks. On top of that, we investigate the outage probability of D2D communication. We first introduce a new definition of outage probability by considering the maximum distance to be allowable for single-hop transmission. Then we study and analyze the outage performance of a multi-hop D2D route. We derive the general closed form expression of outage probability of the multi-hop D2D routes. The results demonstrate that the D2D radio, sharing the same resources as the cellular network, provide higher capacity compared to pure cellular communication where all the data is transmitted through the base station. They also demonstrate that the new method of calculation of D2D multi hop outage probability has better performance than classical method defined in the literature.

Apnea of prematurity

Science.gov (United States)

... medlineplus.gov/ency/article/007227.htm Apnea of prematurity To use the sharing features on this page, ... down or stops from any cause. Apnea of prematurity refers to short episodes of stopped breathing in ...

Ventilatory control and supplemental oxygen in premature infants with apparent chronic lung disease.

Science.gov (United States)

Coste, Ferdinand; Ferkol, Thomas; Hamvas, Aaron; Cleveland, Claudia; Linneman, Laura; Hoffman, Julie; Kemp, James

2015-05-01

Our goal was to evaluate changes in respiratory pattern among premature infants born at newborn intensive care unit. 37 of 49 infants (75.5%) failed the challenge, with severe or sustained falls in SpO2%. Also, 16 of 37 infants (43.2%) who failed had marked increases in the amount of periodic breathing at the time of challenge failure. An unstable respiratory pattern is unmasked with a decrease in inspired oxygen or airflow support in many premature infants. Although infants with significant chronic lung disease may also be predisposed to more periodic breathing, these data suggest that the classification of chronic lung disease of prematurity based solely on clinical requirements for supplemental oxygen or airflow do not account for multiple mechanisms that are likely contributing to the need for respiratory support. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Power plant and utility performance: how world-record outages are being achieved in the USA

International Nuclear Information System (INIS)

Anon.

1997-01-01

Two record-breaking refuelling outages at power reactors in the USA are described. The first, at Browns Ferry 3 BWR, was accomplished in 19 days 39 minutes - a shorter time than for an General Electric BWR anywhere in the world hitherto. The management attribute this success to planning, personnel and performance. As well as refuelling, inspections and maintenance, major modifications were carried out. These included the completion of the installation of digital feedwater reactor level control and digital feedwater heater level control. The second outage, at South Texas Project 2 BWR, at 17 days 14 hours and 10 minutes was the fastest yet recorded for any US nuclear unit. This achievement is ascribed to excellent outage preparation and scheduling, the superior condition of the plant equipment and teamwork and safety consciousness on behalf of the plant personnel. Finally, brief consideration is given to the nuclear performance recovery programme of Commonwealth Edison and Ontario Hydro Nuclear. (UK)

Performance Analysis of Secrecy Outage Probability for AF-Based Partial Relay Selection with Outdated Channel Estimates

Directory of Open Access Journals (Sweden)

Kyu-Sung Hwang

2017-01-01

Full Text Available We study the secrecy outage probability of the amplify-and-forward (AF relaying protocol, which consists of one source, one destination, multiple relays, and multiple eavesdroppers. In this system, the aim is to transmit the confidential messages from a source to a destination via the selected relay in presence of eavesdroppers. Moreover, partial relay selection scheme is utilized for relay selection based on outdated channel state information where only neighboring channel information (source-relays is available and passive eavesdroppers are considered where a transmitter does not have any knowledge of eavesdroppers’ channels. Specifically, we offer the exact secrecy outage probability of the proposed system in a one-integral form as well as providing the asymptotic secrecy outage probability in a closed-form. Numerical examples are given to verify our provided analytical results for different system conditions.

Fuel failure in water reactors: Causes and mitigation. Proceedings of a technical meeting

International Nuclear Information System (INIS)

2003-03-01

The objective of this technical meeting (TM) was to review the present knowledge of the causes and mechanisms of fuel failure in water reactors during normal operational conditions. Emphasis has been given to analysis of failure causes and their mitigation by means of design as well as plant and core operation including strategies for operation with failed fuel. Some information on detection techniques (on-line monitoring and diagnostics, flux tilting, sipping techniques, etc) has also been presented. This TM presented also the progress on the above-mentioned subjects since the last meeting held in 1992 (Dimitrovgrad, Russian Federation). The topics covered in the papers were as follows: Experience feedback on fuel reliability (8 papers); Strategies to avoid or mitigate fuel failures (4 papers); Experimental studies on fuel failures and degradation mechanisms (4 papers); Modelling of fuel failure mechanisms (3 papers); Detection and monitoring during operation or outage (4 papers); Modelling and assessment of fuel failures (3 papers)

Treatment for retinopathy of prematurity in Denmark in a ten-year period (1996-2005): Is the incidence increasing?

DEFF Research Database (Denmark)

Slidsborg, C.; Olesen, H.B.; Jensen, Peter Koch

2008-01-01

about neonatal parameters. These parameters, along with birth in the latter half of the period (2001-2005), were analyzed as risk factors for retinopathy of prematurity. The national registry for blind and visually impaired children was accessed to obtain information about visual impairment attributable...... and 2001 to 2005. Of all of the early-detected, visually impaired children, 16% had not been treated for retinopathy of prematurity and were considered screening failures. CONCLUSIONS. The incidence of retinopathy of prematurity treatment in Denmark has more than doubled during the past half...... contributed to the increased incidence in the latter half of the period. Of the study population, 0.6% were registered as visually impaired because of retinopathy of prematurity within 2 years after birth (early-detected visual impairment). The incidences were not significantly different between 1996 to 2000...

Resolving piping analysis issues to minimize impact on installation activities during refueling outage at nuclear power plants

International Nuclear Information System (INIS)

Bhavnani, D.

1996-01-01

While it is required to maintain piping code compliance for all phases of installation activities during outages at a nuclear plant, it is equally essential to reduce challenges to the installation personnel on how plant modification work should be performed. Plant betterment activities that incorporate proposed design changes are continually implemented during the outages. Supporting analysis are performed to back these activities for operable systems. The goal is to reduce engineering and craft man-hours and minimize outage time. This paper outlines how plant modification process can be streamlined to facilitate construction teams to do their tasks that involve safety related piping. In this manner, installation can proceed by minimizing on the spot analytical effort and reduce downtime to support the proposed modifications. Examples are provided that permit performance of installation work in any sequence. Piping and hangers including the branch lines are prequalified and determined operable. The system is up front analyzed for all possible scenarios. The modification instructions in the work packages is flexible enough to permit any possible installation sequence. The benefit to this approach is large enough in the sense that valuable outage time is not extended and on site analytical work is not required

Neurodevelopmental and Cognitive Outcomes in Children With Intestinal Failure.

Science.gov (United States)

Chesley, Patrick M; Sanchez, Sabrina E; Melzer, Lilah; Oron, Assaf P; Horslen, Simon P; Bennett, F Curt; Javid, Patrick J

2016-07-01

Recent advances in medical and surgical management have led to improved long-term survival in children with intestinal failure. Yet, limited data exist on their neurodevelopmental and cognitive outcomes. The aim of the present study was to measure neurodevelopmental outcomes in children with intestinal failure. Children enrolled in a regional intestinal failure program underwent prospective neurodevelopmental and psychometric evaluation using a validated scoring tool. Cognitive impairment was defined as a mental developmental index Neurodevelopmental impairment was defined as cerebral palsy, visual or hearing impairment, or cognitive impairment. Univariate analyses were performed using the Wilcoxon rank-sum test. Data are presented as median (range). Fifteen children with a remnant bowel length of 18 (5-85) cm were studied at age 17 (12-67) months. Thirteen patients remained dependent on parenteral nutrition. Twelve (80%) subjects scored within the normal range on cognitive testing. Each child with cognitive impairment was noted to have additional risk factors independent of intestinal failure including cardiac arrest and extreme prematurity. On univariate analysis, cognitive impairment was associated with longer inpatient hospital stays, increased number of surgical procedures, and prematurity (P neurodevelopmental impairment. A majority of children with intestinal failure demonstrated normal neurodevelopmental and cognitive outcomes on psychometric testing. These data suggest that children with intestinal failure without significant comorbidity may be at low risk for long-term neurodevelopmental impairment.

Recruitment pattern of sympathetic muscle neurons during premature ventricular contractions in heart failure patients and controls.

Science.gov (United States)

Maslov, Petra Zubin; Breskovic, Toni; Brewer, Danielle N; Shoemaker, J Kevin; Dujic, Zeljko

2012-12-01

Premature ventricular contractions (PVC) elicit larger bursts of multiunit muscle sympathetic nerve activity (MSNA), reflecting the ability to increase postganglionic axonal recruitment. We tested the hypothesis that chronic heart failure (CHF) limits the ability to recruit postganglionic sympathetic neurons as a response to PVC due to the excessive sympathetic activation in these patients. Sympathetic neurograms of sufficient signal-to-noise ratio were obtained from six CHF patients and from six similarly aged control individuals. Action potentials (APs) were extracted from the multiunit sympathetic neurograms during sinus rhythm bursts and during the post-PVC bursts. These APs were classified on the basis of the frequency per second, the content per burst, and the peak-to-peak amplitude, which formed the basis of binning the APs into active clusters. Compared with controls, CHF had higher APs per burst and higher number of active clusters per sinus rhythm burst (P < 0.05). Compared with sinus rhythm bursts, both groups increased AP frequency and the number of active clusters in the post-PVC burst (P < 0.05). However, compared with controls, the increase in burst integral, AP frequency, and APs per burst during the post-PVC burst was less in CHF patients. Nonetheless, the PVC-induced increase in active clusters per burst was similar between the groups. Thus, these CHF patients retained the ability to recruit larger APs but had a diminished ability to increase overall AP content.

Detecting rickets in premature infants and treating them with calcitriol: experience from two cases.

Science.gov (United States)

Chen, Hung-Yi; Chiu, Li-Chien; Yek, Yung-Lee; Chen, Yi-Ling

2012-08-01

A premature infant is a baby born before 37 weeks of gestation. Rickets is a bone disease characterized by growth retardation due to the expansion of the hypertrophic chondrocyte layer of the growth plate and a failure to mineralize bone. Consequently, the bone is soft and permits marked bending and distortion. Although the incidence of rickets in preterm infants is lower due to improvements in health care and nutrition, there are still infants at high risk for this disease. However, few reports are available regarding the treatment of rickets in premature infants. Furthermore, published case studies on experiences with using calcitriol as a potential therapeutic for rickets in premature infants are very rare. Herein, we describe the detection of rickets in premature infants and our experience with calcitriol treatment in two premature infants. We recommended the use of oral calcitriol at a dose of 0.03-0.125 μg/kg/day, in addition to an appropriate formula that provides an adequate amount of calcium and phosphate intake. One patient was prescribed calcitriol for 40 days and the other for 37 days. The two infants gradually recovered and were discharged without any obvious side effects. It is recommended that alkaline phosphatase levels be monitored within 1 month after birth in premature infants with a birth weight of <1000 g. Infants presenting with high alkaline phosphatase levels are candidates for a long bone survey. Copyright © 2012. Published by Elsevier B.V.

Amniotic fluid stem cells prevent follicle atresia and rescue fertility of mice with premature ovarian failure induced by chemotherapy.

Science.gov (United States)

Xiao, Guan-Yu; Liu, I-Hsuan; Cheng, Chun-Chun; Chang, Chia-Chun; Lee, Yen-Hua; Cheng, Winston Teng-Kuei; Wu, Shinn-Chih

2014-01-01

Chemotherapy used to treat cancer may cause irreversible premature ovarian failure (POF). Of late, amniotic fluid stem cells (AFSCs) provide a novel source for regenerative medicine because of their primitive stage, low immunogenicity, and easy accessibility. In this study, we isolated AFSCs from transgenic mice that ubiquitously express enhanced green fluorescence protein (EGFP). These AFSCs exhibited morphologies, immunophenotypes, and mesoderm trilineage differentiation potentials similar to mesenchymal stem cells (MSCs). Further, AFSCs proliferated faster than MSCs and expressed OCT4, a marker for pluripotency. To investigate their potential in recovering fertility in POF model, AFSCs were transplanted into the ovaries of mice with POF six weeks post induction using chemotherapeutic drugs, busulfan and cyclophosphamide. AFSCs could rescue the reproductive ability of mice with POF by preventing follicle atresia and sustaining the healthy follicles. Notably, the transplanted AFSCs did not differentiate into granulosa and germline cells in vivo. After one month, the decreased numbers of transplanted AFSCs accompanied with the reduced beneficial effects indicated that the therapeutic efficacy were directly from AFSCs. These findings demonstrated the therapeutic effects of AFSCs and suggested the promise of AFSCs for treating infertility and POF caused by chemotherapy.

Amniotic fluid stem cells prevent follicle atresia and rescue fertility of mice with premature ovarian failure induced by chemotherapy.

Directory of Open Access Journals (Sweden)

Guan-Yu Xiao

Full Text Available Chemotherapy used to treat cancer may cause irreversible premature ovarian failure (POF. Of late, amniotic fluid stem cells (AFSCs provide a novel source for regenerative medicine because of their primitive stage, low immunogenicity, and easy accessibility. In this study, we isolated AFSCs from transgenic mice that ubiquitously express enhanced green fluorescence protein (EGFP. These AFSCs exhibited morphologies, immunophenotypes, and mesoderm trilineage differentiation potentials similar to mesenchymal stem cells (MSCs. Further, AFSCs proliferated faster than MSCs and expressed OCT4, a marker for pluripotency. To investigate their potential in recovering fertility in POF model, AFSCs were transplanted into the ovaries of mice with POF six weeks post induction using chemotherapeutic drugs, busulfan and cyclophosphamide. AFSCs could rescue the reproductive ability of mice with POF by preventing follicle atresia and sustaining the healthy follicles. Notably, the transplanted AFSCs did not differentiate into granulosa and germline cells in vivo. After one month, the decreased numbers of transplanted AFSCs accompanied with the reduced beneficial effects indicated that the therapeutic efficacy were directly from AFSCs. These findings demonstrated the therapeutic effects of AFSCs and suggested the promise of AFSCs for treating infertility and POF caused by chemotherapy.

Areva: experiences in outage services

International Nuclear Information System (INIS)

Wiemeier, R.; Mueller, N.; Blanco, I. J.

2010-01-01

As the world leader in the nuclear industry, Areva is firmly committed to the safe and reliable operation of the Spanish nuclear power plants. Following this commitment, Areva has established the subsidiary Areva NP Services Spain as a local platform to provide nuclear services for the Spanish nuclear power plants. being integrated and supported by the global Areva Group, Areva NP Services Spain is able to offer services solutions to all customers demands while maintaining close and sustainable relationships with them. This integration also allows the Spanish personnel of Areva to employ their skills by working in multinational teams in international projects. This article will present the capacities, and the most important recent national and international project performed by Areva NP Services Spain in the field of outage services. (Author)

Olkiluoto 1 and 2 - Plant efficiency improvement and lifetime extension-project (PELE) implemented during outages 2010 and 2011

Energy Technology Data Exchange (ETDEWEB)

Kosonen, M.; Hakola, M. [Teollisuuden Voima Oyj, F- 27160 Eurajoki (Finland)

2012-07-01

Teollisuuden Voima Oyj (TVO) is a non-listed public company founded in 1969 to produce electricity for its stakeholders. TVO is the operator of the Olkiluoto nuclear power plant. TVO follows the principle of continuous improvement in the operation and maintenance of the Olkiluoto plant units. The PELE project (Plant Efficiency Improvement and Lifetime Extension), mainly completed during the annual outages in 2010 and 2011, and forms one part of the systematic development of Olkiluoto units. TVO maintains a long-term development program that aims at systematically modernizing the plant unit systems and equipment based on the latest technology. According to the program, the Olkiluoto 1 and Olkiluoto 2 plant units are constantly renovated with the intention of keeping them safe and reliable, The aim of the modernization projects is to improve the safety, reliability, and performance of the plant units. PELE project at Olkiluoto 1 was done in 2010 and at Olkiluoto 2 in 2011. The outage length of Olkiluoto 1 was 26 d 12 h 4 min and Olkiluoto 2 outage length was 28 d 23 h 46 min. (Normal service-outage is about 14 days including refueling and refueling-outage length is about seven days. See figure 1) The PELE project consisted of several single projects collected into one for coordinated project management. Some of the main projects were as follows: - Low pressure turbines: rotor, stator vane, casing and turbine instrumentation replacement. - Replacement of Condenser Cooling Water (later called seawater pumps) pumps - Replacement of inner isolation valves on the main steam lines. - Generator and the generator cooling system replacement. - Low voltage switchgear replacement. This project will continue during future outages. PELE was a success. 100 TVO employees and 1500 subcontractor employees participated in the project. The execution of the PELE projects went extremely well during the outages. The replacement of the low pressure turbines and seawater pumps improved the

Olkiluoto 1 and 2 - Plant efficiency improvement and lifetime extension-project (PELE) implemented during outages 2010 and 2011

International Nuclear Information System (INIS)

Kosonen, M.; Hakola, M.

2012-01-01

Teollisuuden Voima Oyj (TVO) is a non-listed public company founded in 1969 to produce electricity for its stakeholders. TVO is the operator of the Olkiluoto nuclear power plant. TVO follows the principle of continuous improvement in the operation and maintenance of the Olkiluoto plant units. The PELE project (Plant Efficiency Improvement and Lifetime Extension), mainly completed during the annual outages in 2010 and 2011, and forms one part of the systematic development of Olkiluoto units. TVO maintains a long-term development program that aims at systematically modernizing the plant unit systems and equipment based on the latest technology. According to the program, the Olkiluoto 1 and Olkiluoto 2 plant units are constantly renovated with the intention of keeping them safe and reliable, The aim of the modernization projects is to improve the safety, reliability, and performance of the plant units. PELE project at Olkiluoto 1 was done in 2010 and at Olkiluoto 2 in 2011. The outage length of Olkiluoto 1 was 26 d 12 h 4 min and Olkiluoto 2 outage length was 28 d 23 h 46 min. (Normal service-outage is about 14 days including refueling and refueling-outage length is about seven days. See figure 1) The PELE project consisted of several single projects collected into one for coordinated project management. Some of the main projects were as follows: - Low pressure turbines: rotor, stator vane, casing and turbine instrumentation replacement. - Replacement of Condenser Cooling Water (later called seawater pumps) pumps - Replacement of inner isolation valves on the main steam lines. - Generator and the generator cooling system replacement. - Low voltage switchgear replacement. This project will continue during future outages. PELE was a success. 100 TVO employees and 1500 subcontractor employees participated in the project. The execution of the PELE projects went extremely well during the outages. The replacement of the low pressure turbines and seawater pumps improved the

[Retrieval and failure analysis of surgical implants in Brazil: the need for proper regulation].

Science.gov (United States)

Azevedo, Cesar R de Farias; Hippert, Eduardo

2002-01-01

This paper summarizes several cases of metallurgical failure analysis of surgical implants conducted at the Laboratory of Failure Analysis, Instituto de Pesquisas Tecnológicas (IPT), in Brazil. Failures with two stainless steel femoral compression plates, one stainless steel femoral nail plate, one Ti-6Al-4V alloy maxillary reconstruction plate, and five Nitinol wires were investigated. The results showed that the implants were not in accordance with ISO standards and presented evidence of corrosion-assisted fracture. Furthermore, some of the implants presented manufacturing/processing defects which also contributed to their premature failure. Implantation of materials that are not biocompatible may cause several types of adverse effects in the human body and lead to premature implant failure. A review of prevailing health legislation is needed in Brazil, along with the adoption of regulatory mechanisms to assure the quality of surgical implants on the market, providing for compulsory procedures in the reporting and investigation of surgical implants which have failed in service.

Statistical analysis of human maintenance failures of a nuclear power plant

International Nuclear Information System (INIS)

Pyy, P.

2000-01-01

In this paper, a statistical study of faults caused by maintenance activities is presented. The objective of the study was to draw conclusions on the unplanned effects of maintenance on nuclear power plant safety and system availability. More than 4400 maintenance history reports from the years 1992-1994 of Olkiluoto BWR nuclear power plant (NPP) were analysed together with the maintenance personnel. The human action induced faults were classified, e.g., according to their multiplicity and effects. This paper presents and discusses the results of a statistical analysis of the data. Instrumentation and electrical components are especially prone to human failures. Many human failures were found in safety related systems. Similarly, several failures remained latent from outages to power operation. The safety significance was generally small. Modifications are an important source of multiple human failures. Plant maintenance data is a good source of human reliability data and it should be used more, in future. (orig.)

Outage analysis for underlay cognitive networks using incremental regenerative relaying

KAUST Repository

Tourki, Kamel

2013-02-01

Cooperative relay technology has recently been introduced into cognitive radio (CR) networks to enhance the network capacity, scalability, and reliability of end-to-end communication. In this paper, we investigate an underlay cognitive network where the quality of service (QoS) of the secondary link is maintained by triggering an opportunistic regenerative relaying once it falls under an unacceptable level. Analysis is conducted for two schemes, referred to as the channel-state information (CSI)-based and fault-tolerant schemes, respectively, where different amounts of CSI were considered. We first provide the exact cumulative distribution function (cdf) of the received signal-to-noise ratio (SNR) over each hop with colocated relays. Then, the cdf\\'s are used to determine a very accurate closed-form expression for the outage probability for a transmission rate $R$. In a high-SNR region, a floor of the secondary outage probability occurs, and we derive its corresponding expression. We validate our analysis by showing that the simulation results coincide with our analytical results in Rayleigh fading channels. © 1967-2012 IEEE.

Final report of MoReMO 2011-2012. Modelling resilience for maintenance and outage

International Nuclear Information System (INIS)

Gotcheva, N.; Macchi, L.; Oedewald, P.; Eitrheim, M.H.R.; Axelsson, C.; Reiman, T.; Pietikaeinen, E.

2013-04-01

The project Modelling Resilience for Maintenance and Outage (MoReMO) represents a two-year joint effort by VTT Technical Research Centre of Finland, Institute for Energy Technology (IFE, Norway) and Vattenfall (Sweden) to develop and test new approaches for safety management. The overall goal of the project was to present concepts on how resilience can be operationalized and built in a safety critical and socio-technical context. Furthermore, the project also aimed at providing guidance for other organizations that strive to develop and improve their safety performance in a business driven industry. We have applied four approaches in different case studies: Organisational Core Task modelling (OCT), Functional Resonance Analysis Method (FRAM), Efficiency Thoroughness Trade-Off (ETTO) analysis, and Work Practice and Culture Characterisation. During 2011 and 2012 the MoReMO project team has collected data through field observations, interviews, workshops, and document analysis on the work practices and adjustments in maintenance and outage in Nordic NPPs. The project consisted of two sub-studies, one focused on identifying and assessing adjustments and supporting resilient work practices in maintenance activities, while the other focused on handling performance trade-offs in maintenance and outage, as follows: A. Adjustments in maintenance work in Nordic nuclear power plants (VTT and Vattenfall). B. Handling performance trade-offs - the support of adaptive capacities (IFE and Vattenfall). The historical perspective of maintenance and outage management (Chapter 1.1) was provided by Vattenfall. Together, the two sub-studies have provided valuable insights for understanding the rationale behind work practices and adjustments, their effects on resilience, promoting flexibility and balancing between flexibility and reliability. (Author)

Final report of MoReMO 2011-2012. Modelling resilience for maintenance and outage

Energy Technology Data Exchange (ETDEWEB)

Gotcheva, N.; Macchi, L.; Oedewald, P. [Technical Research Centre of Finland (VTT), Espoo (Finland); Eitrheim, M.H.R. [Institute for Energy Technology (IFE) (Norway); Axelsson, C.; Reiman, T.; Pietikaeinen, E. [Ringhals AB (NPP), Vattenfall AB (Sweden)

2013-04-15

The project Modelling Resilience for Maintenance and Outage (MoReMO) represents a two-year joint effort by VTT Technical Research Centre of Finland, Institute for Energy Technology (IFE, Norway) and Vattenfall (Sweden) to develop and test new approaches for safety management. The overall goal of the project was to present concepts on how resilience can be operationalized and built in a safety critical and socio-technical context. Furthermore, the project also aimed at providing guidance for other organizations that strive to develop and improve their safety performance in a business driven industry. We have applied four approaches in different case studies: Organisational Core Task modelling (OCT), Functional Resonance Analysis Method (FRAM), Efficiency Thoroughness Trade-Off (ETTO) analysis, and Work Practice and Culture Characterisation. During 2011 and 2012 the MoReMO project team has collected data through field observations, interviews, workshops, and document analysis on the work practices and adjustments in maintenance and outage in Nordic NPPs. The project consisted of two sub-studies, one focused on identifying and assessing adjustments and supporting resilient work practices in maintenance activities, while the other focused on handling performance trade-offs in maintenance and outage, as follows: A. Adjustments in maintenance work in Nordic nuclear power plants (VTT and Vattenfall). B. Handling performance trade-offs - the support of adaptive capacities (IFE and Vattenfall). The historical perspective of maintenance and outage management (Chapter 1.1) was provided by Vattenfall. Together, the two sub-studies have provided valuable insights for understanding the rationale behind work practices and adjustments, their effects on resilience, promoting flexibility and balancing between flexibility and reliability. (Author)

Prevalence of Feeding Related Issues/Difficulties in Taiwanese Children with History of Prematurity, 2003-2006

Science.gov (United States)

Howe, Tsu-Hsin; Hsu, Chyong-Hsin; Tsai, Mei-Wun

2010-01-01

Feeding problems are common problems seen in premature infants following their discharge from the NICU. However, the prevalence of feeding issues and failure to thrive among preterm infants in Taiwan is uncertain. All former studies of prevalence and identifications of feeding issues were from western countries. Those findings are therefore not…

Outage Analysis of Practical FSO/RF Hybrid System With Adaptive Combining

KAUST Repository

Rakia, Tamer

2015-08-01

Hybrid free-space optical (FSO)/radio-frequency (RF) systems have emerged as a promising solution for high-data-rate wireless transmission. We present and analyze a transmission scheme for the hybrid FSO/RF communication system based on adaptive combining. Specifically, only FSO link is active as long as the instantaneous signal-to-noise ratio (SNR) at the FSO receiver is above a certain threshold level. When it falls below this threshold level, the RF link is activated along with the FSO link and the signals from the two links are combined at the receiver using a dual-branch maximal ratio combiner. Novel analytical expression for the cumulative distribution function (CDF) of the received SNR for the proposed hybrid system is obtained. This CDF expression is used to study the system outage performance. Numerical examples are presented to compare the outage performance of the proposed hybrid FSO/RF system with that of the FSO-only and RF-only systems. © 1997-2012 IEEE.

Zero-Outage Cellular Downlink with Fixed-Rate D2D Underlay

DEFF Research Database (Denmark)

Kiilerich Pratas, Nuno; Popovski, Petar

2015-01-01

. D2D connections can be instrumental in localized aggregation of uplink M2M traffic to a more capable cellular device, before being finally delivered to the Base Station (BS). In this paper we show that a fixed M2M rate is an enabler of efficient Machine-Type D2D underlay operation taking place......, but not the interfering channels from the MTDs to U, we prove that there is a positive downlink rate that can always be decoded by U, leading to zero-outage of the downlink signal. This is a rather surprising consequence of the features of the multiple access channel and the fixed rate RM. We also consider the case...... of a simpler, single-user decoder at U with successive interference cancellation. However, with single-user decoder, a positive zero-outage rate exists only when NM = 1 and is zero when NM > 1. This implies that joint decoding is instrumental in enabling fixed-rate underlay operation....

IVF for premature ovarian failure: first reported births using oocytes donated from a twin sister.

LENUS (Irish Health Repository)

Sills, Eric Scott

2010-01-01

BACKGROUND: Premature ovarian failure (POF) remains a clinically challenging entity because in vitro fertilisation (IVF) with donor oocytes is currently the only treatment known to be effective. METHODS: A 33 year-old nulligravid patient with a normal karyotype was diagnosed with POF; she had a history of failed fertility treatments and had an elevated serum FSH (42 mIU\\/ml). Oocytes donated by her dizygotic twin sister were used for IVF. The donor had already completed a successful pregnancy herself and subsequently produced a total of 10 oocytes after a combined FSH\\/LH superovulation regime. These eggs were fertilised with sperm from the recipient\\'s husband via intracytoplasmic injection and two fresh embryos were transferred to the recipient on day three. RESULTS: A healthy twin pregnancy resulted from IVF; two boys were delivered by caesarean section at 39 weeks\\' gestation. Additionally, four embryos were cryopreserved for the recipient\\'s future use. The sister-donor achieved another natural pregnancy six months after oocyte retrieval, resulting in a healthy singleton delivery. CONCLUSION: POF is believed to affect approximately 1% of reproductive age females, and POF patients with a sister who can be an oocyte donor for IVF are rare. Most such IVF patients will conceive from treatment using oocytes from an anonymous oocyte donor. This is the first report of births following sister-donor oocyte IVF in Ireland. Indeed, while sister-donor IVF has been successfully undertaken by IVF units elsewhere, this is the only known case where oocyte donation involved twin sisters. As with all types of donor gamete therapy, pre-treatment counselling is important in the circumstance of sister oocyte donation.

Outage probability of distributed beamforming with co-channel interference

KAUST Repository

Yang, Liang

2012-03-01

In this letter, we consider a distributed beamforming scheme (DBF) in the presence of equal-power co-channel interferers for both amplify-and-forward and decode-and-forward relaying protocols over Rayleigh fading channels. We first derive outage probability expressions for the DBF systems. We then present a performance analysis for a scheme relying on source selection. Numerical results are finally presented to verify our analysis. © 2011 IEEE.

Follow-up study on premature infants with and without retinopathy of prematurity.

OpenAIRE

Robinson, R; O'Keefe, M

1993-01-01

The ocular complications in population of 131 premature infants, with and without retinopathy of prematurity (ROP) are reported. An increased incidence of strabismus (20% with ROP and 25% without ROP) and myopia (27.5% with ROP and 8.8% without ROP) was shown. Significant visual loss occurred in 10.7% overall, increasing to 35% with stage 3 disease and 100% with stage 4. With the increased survival rate of premature infants, the relevance to future management of this expanding group of young ...

On the outage capacity of the block fading channel at low-power regime

KAUST Repository

Rezki, Zouheir

2014-06-01

Outage performance of the M-block fading with additive white Gaussian noise (BF-AWGN) is investigated at low-power regime. We consider delay-constrained constant-rate communications with perfect channel state information (CSI) at both the transmitter and the receiver (CSI-TR), under a short-term power constraint. We show that selection diversity that allocates all the power to the strongest block is asymptotically optimal. Then, we provide a simple characterization of the outage probability in the regime of interest. We quantify the reward due to CSI-TR over the constant-rate constant-power scheme and show that this reward increases with the delay constraint. For instance, for Rayleigh fading, we find that a power gain up to 4.3 dB is achievable. © 2014 IEEE.

Prediction of power system frequency response after generator outages using neural nets

Energy Technology Data Exchange (ETDEWEB)

Djukanovic, M B; Popovic, D P [Electrotechnicki Inst. ' Nikola Tesla' , Belgrade (Yugoslavia); Sobajic, D J; Pao, Y -H [Case Western Reserve Univ., Cleveland, OH (United States)

1993-09-01

A new methodology is presented for estimating the frequency behaviour of power systems necessary for an indication of under-frequency load shedding in steady-state security assessment. It is well known that large structural disturbances such as generator tripping or load outages can initiate cascading outages, system separation into islands, and even the complete breakup. The approach provides a fairly accurate method of estimating the system average frequency response without making simplifications or neglecting non-linearities and small time constants in the equations of generating units, voltage regulators and turbines. The efficiency of the new procedure is demonstrated using the New England power system model for a series of characteristic perturbations. The validity of the proposed approach is verified by comparison with the simulation of short-term dynamics including effects of control and automatic devices. (author)

Outage probability analysis of wireless sensor networks in the presence of channel fading and spatial correlation

KAUST Repository

Al-Murad, Tamim M.

2011-07-01

Evaluating the reliability of wireless sensor networks is becoming more important as theses networks are being used in crucial applications. The outage probability defined as the probability that the error in the system exceeds a maximum acceptable threshold has recently been used as a measure of the reliability of such systems. In this work we find the outage probability of wireless sensor network in different scenarios of distributed sensing where sensors\\' readings are affected by spatial correlation and in the presence of channel fading. © 2011 IEEE.

Nuclear renaissance or premature try

International Nuclear Information System (INIS)

Coderch, M.

2008-01-01

After the economic failure of the 70's and not having been able to solve for decades its multiple problems, the nuclear industry was suffering a slow but inescapable agony. However, the need to reduce CO 2 emissions and the likely arrival of the worldwide peak of oil production have infused new life to the nuclear option, and it has again become one of the main topics of discussion in the worldwide energy debate. But in this debate we tend to forget that the causes of the abrupt end of the first nuclear era have not disappeared, and that for this reason it may well be that we are lead to a repetition of the events that induced its first demise. The much talked nuclear renaissance is thus likely to end up as a premature miscarriage. (Author)

Premature pubarche is niet altijd onschuldig

NARCIS (Netherlands)

Backes, Manouk; Zwaveling-Soonawala, Nitash; Kamp, Gerdine A.

2012-01-01

Premature pubarche is defined as growth of pubic hair before the age of 8 years in girls and 9 years in boys. In most cases, it is caused by premature adrenarche, which is a premature increased synthesis of androgens in the adrenal gland and is considered to be relatively harmless. Premature

The kinetic and mechanical aspects of hydrogen-induced failure in metals. Ph.D. Thesis, 1971

Science.gov (United States)

Nelson, H. G.

1972-01-01

Premature hydrogen-induced failure observed to occur in many metal systems involves three stages of fracture: (1) crack initiation, (2) stable slow crack growth, and (3) unstable rapid crack growth. The presence of hydrogen at some critical location on the metal surface or within the metal lattice was shown to influence one or both of the first two stages of brittle fracture but has a negligible effect on the unstable rapid crack growth stage. The relative influence of the applied parameters of time, temperature, etc., on the propensity of a metal to exhibit hydrogen induced premature failure was investigated.

Economic and Environmental Impacts of the Columbia-Snake River Extended Lock Outage

Science.gov (United States)

2012-03-01

This reports main objective is to analyze the change in rates and modal costs for shippers, commodity industries and ports prior to, during and after the fifteen week lock outage and to determine the impacts on the environment in the form of energ...

On the Outage Performance of Full-Duplex Selective Decode-and-Forward Relaying

KAUST Repository

Khafagy, Mohammad Galal; Ismail, Amr; Alouini, Mohamed-Slim; Aissa, Sonia

2013-01-01

expression for the end-to-end outage probability that captures their joint effect. With the derived expression in hand, we propose a relay transmit power optimization scheme that only requires the relay knowledge of channel statistics. Finally, we corroborate our analysis with simulations.

Outage Analysis of Mixed Underlay Cognitive RF MIMO and FSO Relaying with Interference Reduction

KAUST Repository

Al-Qahtani, Fawaz S.; El-Malek, Ahmed H. Abd; Ansari, Imran S.; Radaydeh, Redha Mahmoud Mesleh; Zummo, Salam A.

2017-01-01

In this paper, we study the outage performance of multiuser mixed underlay radio frequency (RF)/multidestinations free-space optical (FSO) links. For RF links, we consider a secondary network with multiple users that can communicate with multiple destinations through a relaying node. The relay is equipped with an antenna array at the RF side, and it uses the amplify-and-forward (AF) protocol. The primary users (PUs) are equipped with multiple antennas at transmit and receive nodes. The RF link is subjected to the aggregate PUs interference effect on the secondary network. To reduce the effect of PUs interference on secondary network at the relay node, two interference cancellation (IC) schemes are adopted, which vary in terms of complexity and achieved performance. On the other hand, the multidestination FSO links can be exploited to further enhance the quality of the second hop, and their associated channel models account for pointing errors, intensity modulation/direct detection, and heterodyne detection. For the aforementioned system model, we obtain exact and asymptotic closed-form expressions for the end-to-end outage probability. To further enhance system performance, optimal power allocation between the two hops is obtained based on the derived asymptotic outage probability expressions.

Outage Analysis of Cooperative Transmission with Energy Harvesting Relay: Time Switching versus Power Splitting

Directory of Open Access Journals (Sweden)

Guanyao Du

2015-01-01

Full Text Available This paper investigates the multiuser transmission network with an energy harvesting (EH cooperative relay, where a source transmits independent information to multiple destinations with the help of an energy constrained relay. The relay can harvest energy from the radio frequency (RF signals transmitted from the source, and it helps the multiuser transmission only by consuming the harvested energy. By adopting the time switching and the power splitting relay receiver architectures, we firstly propose two protocols, the time switching cooperative multiuser transmission (TSCMT protocol and the power splitting cooperative multiuser transmission (PSCMT protocol, to enable the simultaneous information processing and EH at the relay for the system. To evaluate the system performance, we theoretically analyze the system outage probability for the two proposed protocols and then derive explicit expressions for each of them, respectively. Numerical results are provided to demonstrate the accuracy of our analytical results and reveal that compared with traditional noncooperative scheme our proposed protocols are green solutions to offer reliable communication and lower system outage probability without consuming additional energy. In particular, for the same transmit power at the source, the PSCMT protocol is superior to the TSCMT protocol to obtain lower system outage probability.

Outage Analysis of Mixed Underlay Cognitive RF MIMO and FSO Relaying with Interference Reduction

KAUST Repository

Al-Qahtani, Fawaz S.

2017-03-22

In this paper, we study the outage performance of multiuser mixed underlay radio frequency (RF)/multidestinations free-space optical (FSO) links. For RF links, we consider a secondary network with multiple users that can communicate with multiple destinations through a relaying node. The relay is equipped with an antenna array at the RF side, and it uses the amplify-and-forward (AF) protocol. The primary users (PUs) are equipped with multiple antennas at transmit and receive nodes. The RF link is subjected to the aggregate PUs interference effect on the secondary network. To reduce the effect of PUs interference on secondary network at the relay node, two interference cancellation (IC) schemes are adopted, which vary in terms of complexity and achieved performance. On the other hand, the multidestination FSO links can be exploited to further enhance the quality of the second hop, and their associated channel models account for pointing errors, intensity modulation/direct detection, and heterodyne detection. For the aforementioned system model, we obtain exact and asymptotic closed-form expressions for the end-to-end outage probability. To further enhance system performance, optimal power allocation between the two hops is obtained based on the derived asymptotic outage probability expressions.

Method for estimating power outages and restoration during natural and man-made events

Science.gov (United States)

Omitaomu, Olufemi A.; Fernandez, Steven J.

2016-01-05

A method of modeling electric supply and demand with a data processor in combination with a recordable medium, and for estimating spatial distribution of electric power outages and affected populations. A geographic area is divided into cells to form a matrix. Within the matrix, supply cells are identified as containing electric substations and demand cells are identified as including electricity customers. Demand cells of the matrix are associated with the supply cells as a function of the capacity of each of the supply cells and the proximity and/or electricity demand of each of the demand cells. The method includes estimating a power outage by applying disaster event prediction information to the matrix, and estimating power restoration using the supply and demand cell information of the matrix and standardized and historical restoration information.

Monitoring Disaster-Related Power Outages Using NASA Black Marble Nighttime Light Product

Science.gov (United States)

Wang, Z.; Román, M. O.; Sun, Q.; Molthan, A. L.; Schultz, L. A.; Kalb, V. L.

2018-04-01

Timely and accurate monitoring of disruptions to the electricity grid, including the magnitude, spatial extent, timing, and duration of net power losses, is needed to improve situational awareness of disaster response and long-term recovery efforts. Satellite-derived Nighttime Lights (NTL) provide an indication of human activity patterns and have been successfully used to monitor disaster-related power outages. The global 500 m spatial resolution National Aeronautics and Space Administration (NASA) Black Marble NTL daily standard product suite (VNP46) is generated from Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) onboard the NASA/National Oceanic and Atmospheric Administration (NOAA) Suomi National Polar-orbiting Partnership (Suomi- NPP) satellite, which began operations on 19 January 2012. With its improvements in product accuracy (including critical atmospheric and BRDF correction routines), the VIIRS daily Black Mable product enables systematic monitoring of outage conditions across all stages of the disaster management cycle.

Recent Performance of and Plasma Outage Studies with the SNS H- Source

Energy Technology Data Exchange (ETDEWEB)

Stockli, Martin P [ORNL; Han, Baoxi [ORNL; Murray Jr, S N [ORNL; Pennisi, Terry R [ORNL; Piller, Chip [ORNL; Santana, Manuel [ORNL; Welton, Robert F [ORNL

2016-01-01

SNS ramps to higher power levels that can be sustained with high availability. The goal is 1.4 MW despite a compromised RFQ, which requires higher RF power than design levels to approach the nominal beam transmission. Unfortunately at higher power the RFQ often loses its thermal stability, a problem apparently enhanced by beam losses and high influxes of hydrogen. Delivering as much H- beam as possible with the least amount of hydrogen led to plasma outages. The root cause is the dense 1-ms long ~55-kW 2-MHz plasma pulses reflecting ~90% of the continuous ~300W, 13-MHz power, which was mitigated with a 4-ms filter for the reflected power signal and an outage resistant, slightly-detuned 13-MHz match. Lowering the H2 also increased the H- beam current to ~55 mA, and increased the transmission by ~7%.

Radiological protection for the ANGRA 1 steam generator replacement outage

International Nuclear Information System (INIS)

Oliveira, Magno Jose de; Amaral, Marcos Antonio do; Minelli, Edson; Ferreira, William Alves

2009-01-01

The Angra 1 Nuclear Power Plant (NPP) is a Westinghouse two-loop plant with net output before its 1P16 Outage of 632 MWe, with the Old Steam Generators (OSG) type model D3, which were replaced by two new Steam Generators with feed water-ring system. Localized in Angra dos Reis, Rio de Janeiro - Brazil, Angra 1 started in commercial operation in 1985 and, from the beginning problems related to corrosion have appeared in the Inconel 600 alloy of the tubes. The corrosion problems indicated the necessity for a strong control of the tubes thicknesses and, after a time, the ELETRONUCLEAR decided to replace the OSG. In 2009, ELETRONUCLEAR initiated in January 24, the actions for the Steam Generators Replacement - SGR. During the SGR process, several controls were applied in field, which made possible to have no radiological accidents, no dose limits exceeded, and permitted to achieve a very good result in terms of Collective Dose. This paper describes the radiological controls applied for the Angra 1 Steam Generator Replacement Outage, the radiological protection team sizing and distribution and the obtained results. (author)

Prematures with and without Regressed Retinopathy of Prematurity: Comparison of Long-Term (6-10 Years) Ophthalmological Morbidity.

Science.gov (United States)

Cats, Bernard P.; Tan, Karel E. W. P.

Reporting long-term ophthalmologic sequelae among ex-prematures at 6 to 10 years of age, this study compares 42 ex-premature infants who had had regressed forms of retinopathy of prematurity (ROP) during the neonatal period with 42 matched non-ROP ex-premature controls at 6 to 10 years of age. Subjects were subdivided into four groups: (1) ROP…

Outage Analysis of Train-to-Train Communication Model over Nakagami-m Channel in High-Speed Railway

Directory of Open Access Journals (Sweden)

Pengyu Liu

2013-01-01

Full Text Available This paper analyzes the end-to-end outage performance of high-speed-railway train-to-train communication model in high-speed railway over independent identical and nonidentical Nakagami-m channels. The train-to-train communication is inter-train communication without an aid of infrastructure (for base station. Source train uses trains on other rail tracks as relays to transmit signals to destination train on the same track. The mechanism of such communication among trains can be divided into three cases based on occurrence of possible-occurrence relay trains. We first present a new closed form for the sum of squared independent Nakagami-m variates and then derive an expression for the outage probability of the identical and non-identical Nakagami-m channels in three cases. In particular, the problem is improved by the proposed formulation that statistic for sum of squared Nakagami-m variates with identical m tends to be infinite. Numerical analysis indicates that the derived analytic results are reasonable and the outage performance is better over Nakagami-m channel in high-speed railway scenarios.

Electric infrastructure failures in Nigeria: a survey-based analysis of the costs and adjustment responses

International Nuclear Information System (INIS)

Adenikinju, A.F.

2003-01-01

This paper examines the cost of electricity shortages on the Nigerian manufacturing sector. Utilizing the data obtained from a 1998 nationwide survey, the paper details the various costs from power outages and examines the response of manufacturers to the infrastructure problem. The findings of the study confirm that the cost of electricity failures on the Nigerian manufacturing sector is quite high. Firms incur huge costs on the provision of expensive back-up to minimise the expected outage costs. The average costs of this back-up are on the average 3 times the cost of publicly supplied electricity. The marginal cost estimates also indicate that the cost of kWh of unserved electricity in Nigeria is very high. Small-scale firms bear the greater proportion of the cost of the power failure. A situation where firms spend as much as 20-30% of initial investment on the acquisition of facilities to enhance electricity supply reliability has a significant negative impact on costs competitiveness of the manufacturing sector. Thus, the study supports current government efforts to privatise the public monopoly and liberalizes the electricity market. These hopefully will mitigate the burden of poor power supply as well as introduce the needed competition into the electricity market in the country

Body growth and brain development in premature babies: an MRI study

International Nuclear Information System (INIS)

Tzarouchi, Loukia C.; Zikou, Anastasia; Kosta, Paraskevi; Argyropoulou, Maria I.; Drougia, Aikaterini; Andronikou, Styliani; Astrakas, Loukas G.

2014-01-01

Prematurity and intrauterine growth restriction are associated with neurodevelopmental disabilities. To assess the relationship between growth status and regional brain volume (rBV) and white matter microstructure in premature babies at around term-equivalent age. Premature infants (n= 27) of gestational age (GA): 29.8 ± 2.1 weeks, with normal brain MRI scans were studied at corrected age: 41.2 ± 1.4 weeks. The infants were divided into three groups: 1) appropriate for GA at birth and at the time of MRI (AGA), 2) small for GA at birth with catch-up growth at the time of MRI (SGA a ) and 3) small for GA at birth with failure of catch-up growth at the time of MRI (SGA b ). The T1-weighted images were segmented into 90 rBVs using the SPM8/IBASPM and differences among groups were assessed. Fractional anisotropy (FA) was measured bilaterally in 15 fiber tracts and its relationship to GA and somatometric measurements was explored. Lower rBV was observed in SGA b in superior and anterior brain areas. A positive correlation was demonstrated between FA and head circumference and body weight. Body weight was the only significant predictor for FA (P< 0.05). In premature babies, catch-up growth is associated with regional brain volume catch-up at around term-equivalent age, starting from the brain areas maturing first. Body weight seems to be a strong predictor associated with WM microstructure in brain areas related to attention, language, cognition, memory and executing functioning. (orig.)

Body growth and brain development in premature babies: an MRI study

Energy Technology Data Exchange (ETDEWEB)

Tzarouchi, Loukia C.; Zikou, Anastasia; Kosta, Paraskevi; Argyropoulou, Maria I. [University of Ioannina, Department of Radiology, Medical School, Ioannina (Greece); Drougia, Aikaterini; Andronikou, Styliani [University of Ioannina, Intensive Care Unit, Child Health Department, Medical School, Ioannina (Greece); Astrakas, Loukas G. [University of Ioannina, Department of Medical Physics, Medical School, Ioannina (Greece)

2014-03-15

Prematurity and intrauterine growth restriction are associated with neurodevelopmental disabilities. To assess the relationship between growth status and regional brain volume (rBV) and white matter microstructure in premature babies at around term-equivalent age. Premature infants (n= 27) of gestational age (GA): 29.8 ± 2.1 weeks, with normal brain MRI scans were studied at corrected age: 41.2 ± 1.4 weeks. The infants were divided into three groups: 1) appropriate for GA at birth and at the time of MRI (AGA), 2) small for GA at birth with catch-up growth at the time of MRI (SGA{sub a}) and 3) small for GA at birth with failure of catch-up growth at the time of MRI (SGA{sub b}). The T1-weighted images were segmented into 90 rBVs using the SPM8/IBASPM and differences among groups were assessed. Fractional anisotropy (FA) was measured bilaterally in 15 fiber tracts and its relationship to GA and somatometric measurements was explored. Lower rBV was observed in SGA{sub b} in superior and anterior brain areas. A positive correlation was demonstrated between FA and head circumference and body weight. Body weight was the only significant predictor for FA (P< 0.05). In premature babies, catch-up growth is associated with regional brain volume catch-up at around term-equivalent age, starting from the brain areas maturing first. Body weight seems to be a strong predictor associated with WM microstructure in brain areas related to attention, language, cognition, memory and executing functioning. (orig.)

MONITORING DISASTER-RELATED POWER OUTAGES USING NASA BLACK MARBLE NIGHTTIME LIGHT PRODUCT

Directory of Open Access Journals (Sweden)

Z. Wang

2018-04-01

Full Text Available Timely and accurate monitoring of disruptions to the electricity grid, including the magnitude, spatial extent, timing, and duration of net power losses, is needed to improve situational awareness of disaster response and long-term recovery efforts. Satellite-derived Nighttime Lights (NTL provide an indication of human activity patterns and have been successfully used to monitor disaster-related power outages. The global 500 m spatial resolution National Aeronautics and Space Administration (NASA Black Marble NTL daily standard product suite (VNP46 is generated from Visible Infrared Imaging Radiometer Suite (VIIRS Day/Night Band (DNB onboard the NASA/National Oceanic and Atmospheric Administration (NOAA Suomi National Polar-orbiting Partnership (Suomi- NPP satellite, which began operations on 19 January 2012. With its improvements in product accuracy (including critical atmospheric and BRDF correction routines, the VIIRS daily Black Mable product enables systematic monitoring of outage conditions across all stages of the disaster management cycle.

Role of the different sexuality domains on the sexual function of women with premature ovarian failure.

Science.gov (United States)

Benetti-Pinto, Cristina Laguna; Soares, Patrícia Magda; Giraldo, Helena Patrícia Donovan; Yela, Daniela Angerame

2015-03-01

Women with premature ovarian failure (POF) often manifest complaints involving different aspects of sexual function (SF), regardless of using hormone therapy. SF involves a complex interaction between physical, psychological, and sociocultural aspects. There are doubts about the impact of different complaints on the global context of SF of women with POF. To evaluate the percentage of influence of each of the sexuality domains on the SF in women with POF. Cross-sectional study with 80 women with POF, matched by age to 80 women with normal gonadal function. We evaluated SF through the "Female Sexual Function Index" (FSFI), a comparison between the POF and control groups using the Mann-Whitney test. Component exploratory factor analysis was used to assess the proportional influence of each domain on the composition of the overall SF for women in the POF group. SF was evaluated using FSFI. Exploratory Factor Analysis for components was used to evaluate the role of each domain on the SF of women with POF. The FSFI score was significantly worse for women with POF, with a decrease in arousal, lubrication, orgasm, satisfaction, and dyspareunia. Exploratory factor analysis of SF showed that the domain with greater influence in the SF was arousal, followed by desire, together accounting for 41% of the FSFI. The domains with less influence were dyspareunia and lubrication, which together accounted for 25% of the FSFI. Women with POF have impaired SF, determined mainly by changes in arousal and desire. Aspects related to lubrication and dyspareunia complaints have lower determination coefficient in SF. These results are important in adapting the approach of sexual disorders in this group of women. © 2014 International Society for Sexual Medicine.

Outage and BER analysis for ultrawideband-based WPAN in Nakagami-m fading channels

KAUST Repository

Mehbodniya, Abolfazl; Aissa, Sonia

2011-01-01

layer. Approximate expressions for the outage probability and average bit error rate (BER) are derived in closed form for the MB-OFDM target receiver, taking into account multi-user interference (MUI), as well as external interference in the form of time

On the outage capacity of the block fading channel at low-power regime

KAUST Repository

Rezki, Zouheir; Alouini, Mohamed-Slim

2014-01-01

the transmitter and the receiver (CSI-TR), under a short-term power constraint. We show that selection diversity that allocates all the power to the strongest block is asymptotically optimal. Then, we provide a simple characterization of the outage probability

Exact Outage Probability of Dual-Hop CSI-Assisted AF Relaying Over Nakagami-m Fading Channels

KAUST Repository

Xia, Minghua

2012-10-01

In this correspondence, considering dual-hop channel state information (CSI)-assisted amplify-and-forward (AF) relaying over Nakagami- m fading channels, the cumulative distribution function (CDF) of the end-to-end signal-to-noise ratio (SNR) is derived. In particular, when the fading shape factors m1 and m2 at consecutive hops take non-integer values, the bivariate H-function and G -function are exploited to obtain an exact analytical expression for the CDF. The obtained CDF is then applied to evaluate the outage performance of the system under study. The analytical results of outage probability coincide exactly with Monte-Carlo simulation results and outperform the previously reported upper bounds in the low and medium SNR regions.

Hypoxia-induced retinal neovascularization in zebrafish embryos: a potential model of retinopathy of prematurity.

Science.gov (United States)

Wu, Yu-Ching; Chang, Chao-Yuan; Kao, Alex; Hsi, Brian; Lee, Shwu-Huey; Chen, Yau-Hung; Wang, I-Jong

2015-01-01

Retinopathy of prematurity, formerly known as a retrolental fibroplasia, is a leading cause of infantile blindness worldwide. Retinopathy of prematurity is caused by the failure of central retinal vessels to reach the retinal periphery, creating a nonperfused peripheral retina, resulting in retinal hypoxia, neovascularization, vitreous hemorrhage, vitreoretinal fibrosis, and loss of vision. We established a potential retinopathy of prematurity model by using a green fluorescent vascular endothelium zebrafish transgenic line treated with cobalt chloride (a hypoxia-inducing agent), followed by GS4012 (a vascular endothelial growth factor inducer) at 24 hours postfertilization, and observed that the number of vascular branches and sprouts significantly increased in the central retinal vascular trunks 2-4 days after treatment. We created an angiography method by using tetramethylrhodamine dextran, which exhibited severe vascular leakage through the vessel wall into the surrounding retinal tissues. The quantification of mRNA extracted from the heads of the larvae by using real-time quantitative polymerase chain reaction revealed a twofold increase in vegfaa and vegfr2 expression compared with the control group, indicating increased vascular endothelial growth factor signaling in the hypoxic condition. In addition, we demonstrated that the hypoxic insult could be effectively rescued by several antivascular endothelial growth factor agents such as SU5416, bevacizumab, and ranibizumab. In conclusion, we provide a simple, highly reproducible, and clinically relevant retinopathy of prematurity model based on zebrafish embryos; this model may serve as a useful platform for clarifying the mechanisms of human retinopathy of prematurity and its progression.

Feeding premature neonate

DEFF Research Database (Denmark)

Dam, Mie S.; Juhl, Sandra M.; Sangild, Per T.

2017-01-01

Kinship, understood as biogenetic proximity, between a chosen animal model and a human patient counterpart, is considered essential to the process of ‘translating’ research from the experimental animal laboratory to the human clinic. In the Danish research centre, NEOMUNE, premature piglets are fed...... a novel milk diet (bovine colostrum) to model the effects of this new diet in premature infants. Our ethnographic fieldwork in an experimental pig laboratory and a neonatal intensive care unit (NICU) in 2013–2014 shows that regardless of biogenetics, daily practices of feeding, housing, and clinical care...... the researchers refer to as the ‘translatability’ of the results. In the NICU, parents of premature infants likewise imagine a kind of interspecies kinship when presented with the option to supplement mother's own milk with bovine colostrum for the first weeks after birth. However, in this setting the NICU...

On Secrecy Outage of Relay Selection in Underlay Cognitive Radio Networks over Nakagami-m Fading Channels

KAUST Repository

Lei, Hongjiang; Zhang, Huan; Ansari, Imran Shafique; Ren, Zhi; Pan, Gaofeng; Qaraqe, Khalid A.; Alouini, Mohamed-Slim

2017-01-01

In this paper, the secrecy outage performance of an underlay cognitive decode-and-forward relay network over independent but not necessarily identical distributed (i.n.i.d) Nakagami-m fading channels is investigated, in which the secondary user transmitter communicates with the secondary destination via relays, and an eavesdropper attempts to overhear the information. Based on whether the channel state information (CSI) of the wiretap links is available or not, we analyze the secrecy outage performance with optimal relay selection (ORS) and suboptimal relay selection (SRS) schemes, and multiple relays combining scheme (MRC) scheme is considered for comparison purpose. The exact and asymptotic closed-form expressions for the secrecy outage probability with three different relay selection schemes are derived and verified by Monte-Carlo simulations. The numerical results illustrate that ORS scheme always outperforms SRS and MRC schemes, and SRS scheme is better than MRC scheme in the lower fading parameters scenario. Furthermore, through asymptotic analysis, we find that these three different schemes achieve the same secrecy diversity order, which is determined by the number of the relays, and the fading parameters of the links among the relays and the destination.

On Secrecy Outage of Relay Selection in Underlay Cognitive Radio Networks over Nakagami-m Fading Channels

KAUST Repository

Lei, Hongjiang

2017-10-02

In this paper, the secrecy outage performance of an underlay cognitive decode-and-forward relay network over independent but not necessarily identical distributed (i.n.i.d) Nakagami-m fading channels is investigated, in which the secondary user transmitter communicates with the secondary destination via relays, and an eavesdropper attempts to overhear the information. Based on whether the channel state information (CSI) of the wiretap links is available or not, we analyze the secrecy outage performance with optimal relay selection (ORS) and suboptimal relay selection (SRS) schemes, and multiple relays combining scheme (MRC) scheme is considered for comparison purpose. The exact and asymptotic closed-form expressions for the secrecy outage probability with three different relay selection schemes are derived and verified by Monte-Carlo simulations. The numerical results illustrate that ORS scheme always outperforms SRS and MRC schemes, and SRS scheme is better than MRC scheme in the lower fading parameters scenario. Furthermore, through asymptotic analysis, we find that these three different schemes achieve the same secrecy diversity order, which is determined by the number of the relays, and the fading parameters of the links among the relays and the destination.

Outage Probability versus Fairness Trade-off in Opportunistic Relay Selection with Outdated CSI

Directory of Open Access Journals (Sweden)

Vicario JoseLopez

2009-01-01

Full Text Available We analyze the existing trade-offs in terms of system performance versus fairness of a cooperative system based on opportunistic relay selection (ORS and with outdated channel state information (CSI. In particular, system performance is analytically evaluated in terms of outage probability, and the fairness behavior is assessed based on the power consumption at the different relays. In order to improve the fairness behavior of ORS while keeping the selection diversity gain, we propose a relay selection mechanism where the relay with the highest normalized signal-to-noise ratio (SNR is selected for relaying the source's information. The proposed strategy is compared with existing relay selection strategies by adopting a novel graphical representation inspired by expected profit versus risk plots used in modern portfolio theory. As shown in the paper, this strategy allows operating the system in more favorable points of the outage versus fairness region.

Family Perspectives on Prematurity

Science.gov (United States)

Zero to Three (J), 2003

2003-01-01

In this article, seven families describe their experiences giving birth to and raising a premature baby. Their perspectives vary, one from another, and shift over time, depending on each family's circumstances and the baby's developmental course. Experiences discussed include premature labor, medical interventions and the NICU, bringing the baby…

Prenatal stress, prematurity and asthma

Science.gov (United States)

Medsker, Brock; Forno, Erick; Simhan, Hyagriv; Celedón, Juan C.

2016-01-01

Asthma is the most common chronic disease of childhood, affecting millions of children in the U.S. and worldwide. Prematurity is a risk factor for asthma, and certain ethnic or racial minorities such as Puerto Ricans and non-Hispanic Blacks are disproportionately affected by both prematurity and asthma. In this review, we examine current evidence to support maternal psychosocial stress as a putative link between prematurity and asthma, while also focusing on disruption of the hypothalamic-pituitary-adrenal (HPA) axis and immune responses as potential underlying mechanisms for stress-induced “premature asthma”. Prenatal stress may not only cause abnormalities in the HPA axis but also epigenetic changes in the fetal glucocorticoid receptor gene (NR3C1), leading to impaired glucocorticoid metabolism. Moreover, maternal stress can alter fetal cytokine balance, favoring Th2 (allergic) immune responses characteristic of atopic asthma: IL-6, which has been associated with premature labor, can promote Th2 responses by stimulating production of IL-4 and IL-13. Given a link among stress, prematurity, and asthma, future research should include birth cohorts aimed at confirming and better characterizing “premature asthma”. If confirmed, clinical trials of prenatal maternal stress reduction would be warranted to reduce the burden of these common co-morbidities. While awaiting the results of such studies, sound policies to prevent domestic and community violence (e.g. from firearms) are justified, not only by public safety but also by growing evidence of detrimental effects of violence-induced stress on psychiatric and somatic health. PMID:26676148

Treatment of posthemorrhagic hydrocephalus in premature infants with subcutaneous reservoir drainage.

Science.gov (United States)

Yu, Bo; Li, Shasha; Lin, Zhenlang; Zhang, Nu

2009-01-01

To investigate the effectiveness of subcutaneous reservoir drainage as a treatment for the different types of posthemorrhagic hydrocephalus in premature infants. 11 premature infants with posthemorrhagic hydrocephalus underwent subcutaneous reservoir embedment surgery, and cerebrospinal fluid (CSF) was drained via the reservoir intermittently for 8 weeks. During the period of drainage, ultrasound and computerized tomography were used to measure ventricle size. CSF examinations were performed routinely to assess the presence of intraventricular hemorrhage (IVH) and/or infection. (1) Five infants were diagnosed as having obstructive hydrocephalus; 2 had nearly normal ventricle sizes with treatment and drainage was stopped after 8 weeks, 2 had nearly normal ventricle sizes after 4 more weeks of drainage, and 1 underwent ventriculoperitoneal shunt (V-P shunt) surgery due to failure of ventricle size reduction. (2) Six infants were diagnosed as having communicating hydrocephalus; 4 had further enlarged ventricle size after 8 weeks and underwent V-P shunt surgery, 1 had treatment aborted at week 8 of drainage, and only 1 had moderate reduction of ventricle size after 8 weeks. (3) None of the 11 infants had progressive IVH and/or intracranial infection during drainage. Subcutaneous reservoir drainage is a suitable and safe treatment for posthemorrhagic hydrocephalus in premature infants. It is more effective for obstructive hydrocephalus than for communicating hydrocephalus. Copyright (c) 2009 S. Karger AG, Basel.

A Unified Simulation Approach for the Fast Outage Capacity Evaluation over Generalized Fading Channels

KAUST Repository

Rached, Nadhir B.; Kammoun, Abla; Alouini, Mohamed-Slim; Tempone, Raul

2016-01-01

The outage capacity (OC) is among the most important performance metrics of communication systems over fading channels. The evaluation of the OC, when equal gain combining (EGC) or maximum ratio combining (MRC) diversity techniques are employed

A NANOS3 mutation linked to protein degradation causes premature ovarian insufficiency

OpenAIRE

Wu, X; Wang, B; Dong, Z; Zhou, S; Liu, Z; Shi, G; Cao, Y; Xu, Y

2013-01-01

Primary ovarian insufficiency (POI), or premature ovarian failure, is defined as the cessation of ovarian function before the age of 40. An insufficient ovarian follicle pool derived from primordial germ cells (PGCs) is an important cause of POI. Although the Nanos gene family is known to be required for PGC development and maintenance in diverse model organisms, the relevance of this information to human biology is not yet clear. In this study, we screened the coding regions of the NANOS1, N...

Analytical Study of different types Of network failure detection and possible remedies

Science.gov (United States)

Saxena, Shikha; Chandra, Somnath

2012-07-01

Faults in a network have various causes,such as the failure of one or more routers, fiber-cuts, failure of physical elements at the optical layer, or extraneous causes like power outages. These faults are usually detected as failures of a set of dependent logical entities and the links affected by the failed components. A reliable control plane plays a crucial role in creating high-level services in the next-generation transport network based on the Generalized Multiprotocol Label Switching (GMPLS) or Automatically Switched Optical Networks (ASON) model. In this paper, approaches to control-plane survivability, based on protection and restoration mechanisms, are examined. Procedures for the control plane state recovery are also discussed, including link and node failure recovery and the concepts of monitoring paths (MPs) and monitoring cycles (MCs) for unique localization of shared risk linked group (SRLG) failures in all-optical networks. An SRLG failure is a failure of multiple links due to a failure of a common resource. MCs (MPs) start and end at same (distinct) monitoring location(s). They are constructed such that any SRLG failure results in the failure of a unique combination of paths and cycles. We derive necessary and sufficient conditions on the set of MCs and MPs needed for localizing an SRLG failure in an arbitrary graph. Procedure of Protection and Restoration of the SRLG failure by backup re-provisioning algorithm have also been discussed.

Your Premature Baby: Low Birthweight

Science.gov (United States)

... volunteer leader Partner Spotlight Become a partner World Prematurity Day What's happening in your area Find out ... to remove damaged parts of intestine. Retinopathy of prematurity (also called ROP) . ROP affects blood vessels in ...

Health Issues of Premature Babies

Science.gov (United States)

... they leave the hospital for home. Retinopathy of Prematurity (ROP) What It Is: ROP is an eye ... sometimes seen in preterm babies include anemia of prematurity (a low red blood cell count) and heart ...

Outage and Capacity Performance Evaluation of Distributed MIMO Systems over a Composite Fading Channel

Directory of Open Access Journals (Sweden)

Wenjie Peng

2014-01-01

Full Text Available The exact closed-form expressions regarding the outage probability and capacity of distributed MIMO (DMIMO systems over a composite fading channel are derived. This is achieved firstly by using a lognormal approximation to a gamma-lognormal distribution when a mobile station (MS in the cell is in a fixed position, and the so-called maximum ratio transmission/selected combining (MRT-SC and selected transmission/maximum ratio combining (ST-MRC schemes are adopted in uplink and downlink, respectively. Then, based on a newly proposed nonuniform MS cell distribution model, which is more consistent with the MS cell hotspot distribution in an actual communication environment, the average outage probability and capacity formulas are further derived. Finally, the accuracy of the approximation method and the rationality of the corresponding theoretical analysis regarding the system performance are proven and illustrated by computer simulations.

End face seals in high pressure water - learning from those failures

International Nuclear Information System (INIS)

Metcalfe, R.

1976-08-01

End face seals are complex devices which are used widely in shaft sealing of rotating equipment. In the nuclear industry, working at the limits of present sealing technlogy with a massive economic dependence on reliability, the importance of scrutinizing seal failures and thereby attempting to prevent premature failures from recurring was fully realized. This paper describes Canadian nuclear sealing experience. Failed seal data is presented; practical examples are categorized as to cause and type. (author)

Retinal vascular speed prematurity requiring treatment.

Science.gov (United States)

Solans Pérez de Larraya, Ana M; Ortega Molina, José M; Fernández, José Uberos; Escudero Gómez, Júlia; Salgado Miranda, Andrés D; Chaves Samaniego, Maria J; García Serrano, José L

2018-03-01

To analyse the speed of temporal retinal vascularisation in preterm infants included in the screening programme for retinopathy of prematurity. A total of 185 premature infants were studied retrospectively between 2000 and 2017 in San Cecilio University Hospital of Granada, Spain. The method of binocular indirect ophthalmoscopy with indentation was used for the examination. The horizontal disc diameter was used as a unit of length. Speed of temporal retinal vascularisation (disc diameter/week) was calculated as the ratio between the extent of temporal retinal vascularisation (disc diameter) and the time in weeks. The weekly temporal retinal vascularisation (0-1.25 disc diameter/week, confidence interval) was significantly higher in no retinopathy of prematurity (0.73 ± 0.22 disc diameter/week) than in stage 1 retinopathy of prematurity (0.58 ± 0.22 disc diameter/week). It was also higher in stage 1 than in stages 2 (0.46 ± 0.14 disc diameter/week) and 3 of retinopathy of prematurity (0.36 ± 0.18 disc diameter/week). The rate of temporal retinal vascularisation (disc diameter/week) decreases when retinopathy of prematurity stage increases. The area under the receiver operating characteristic curve was 0.85 (95% confidence interval: 0.79-0.91) for retinopathy of prematurity requiring treatment versus not requiring treatment. The best discriminative cut-off point was a speed of retinal vascularisation prematurity may be required. However, before becoming a new standard of care for treatment, it requires careful documentation, with agreement between several ophthalmologists.

Reliability analysis of multi-trigger binary systems subject to competing failures

International Nuclear Information System (INIS)

Wang, Chaonan; Xing, Liudong; Levitin, Gregory

2013-01-01

This paper suggests two combinatorial algorithms for the reliability analysis of multi-trigger binary systems subject to competing failure propagation and failure isolation effects. Propagated failure with global effect (PFGE) is referred to as a failure that not only causes outage to the component from which the failure originates, but also propagates through all other system components causing the entire system failure. However, the propagation effect from the PFGE can be isolated in systems with functional dependence (FDEP) behavior. This paper studies two distinct consequences of PFGE resulting from a competition in the time domain between the failure isolation and failure propagation effects. As compared to existing works on competing failures that are limited to systems with a single FDEP group, this paper considers more complicated cases where the systems have multiple dependent FDEP groups. Analysis of such systems is more challenging because both the occurrence order between the trigger failure event and PFGE from the dependent components and the occurrence order among the multiple trigger failure events have to be considered. Two combinatorial and analytical algorithms are proposed. Both of them have no limitation on the type of time-to-failure distributions for the system components. Their correctness is verified using a Markov-based method. An example of memory systems is analyzed to demonstrate and compare the applications and advantages of the two proposed algorithms. - Highlights: ► Reliability of binary systems with multiple dependent functional dependence groups is analyzed. ► Competing failure propagation and failure isolation effect is considered. ► The proposed algorithms are combinatorial and applicable to any arbitrary type of time-to-failure distributions for system components.

Genome-wide linkage in a highly consanguineous pedigree reveals two novel loci on chromosome 7 for non-syndromic familial Premature Ovarian Failure.

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Sandrine Caburet

Full Text Available BACKGROUND: The human condition known as Premature Ovarian Failure (POF is characterized by loss of ovarian function before the age of 40. A majority of POF cases are sporadic, but 10-15% are familial, suggesting a genetic origin of the disease. Although several causal mutations have been identified, the etiology of POF is still unknown for about 90% of the patients. METHODOLOGY/PRINCIPAL FINDINGS: We report a genome-wide linkage and homozygosity analysis in one large consanguineous Middle-Eastern POF-affected family presenting an autosomal recessive pattern of inheritance. We identified two regions with a LOD(max of 3.26 on chromosome 7p21.1-15.3 and 7q21.3-22.2, which are supported as candidate regions by homozygosity mapping. Sequencing of the coding exons and known regulatory sequences of three candidate genes (DLX5, DLX6 and DSS1 included within the largest region did not reveal any causal mutations. CONCLUSIONS/SIGNIFICANCE: We detect two novel POF-associated loci on human chromosome 7, opening the way to the identification of new genes involved in the control of ovarian development and function.

Sampled-data-based vibration control for structural systems with finite-time state constraint and sensor outage.

Science.gov (United States)

Weng, Falu; Liu, Mingxin; Mao, Weijie; Ding, Yuanchun; Liu, Feifei

2018-05-10

The problem of sampled-data-based vibration control for structural systems with finite-time state constraint and sensor outage is investigated in this paper. The objective of designing controllers is to guarantee the stability and anti-disturbance performance of the closed-loop systems while some sensor outages happen. Firstly, based on matrix transformation, the state-space model of structural systems with sensor outages and uncertainties appearing in the mass, damping and stiffness matrices is established. Secondly, by considering most of those earthquakes or strong winds happen in a very short time, and it is often the peak values make the structures damaged, the finite-time stability analysis method is introduced to constrain the state responses in a given time interval, and the H-infinity stability is adopted in the controller design to make sure that the closed-loop system has a prescribed level of disturbance attenuation performance during the whole control process. Furthermore, all stabilization conditions are expressed in the forms of linear matrix inequalities (LMIs), whose feasibility can be easily checked by using the LMI Toolbox. Finally, numerical examples are given to demonstrate the effectiveness of the proposed theorems. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

The costs of power outages: A case study from Cyprus

International Nuclear Information System (INIS)

Zachariadis, Theodoros; Poullikkas, Andreas

2012-01-01

We study the costs of electricity disruptions in Cyprus, which suffered severe power shortages in summer 2011 after an explosion that destroyed 60% of its power generating capacity. We employ both economic and engineering approaches to assess these costs. Among other calculations, we provide estimates of the value of lost load by economic sector and the hourly value of electricity by season and type of day. The results of two economic methods employed to assess welfare losses differ largely, indicating that the assessment of outage costs is associated with many uncertainties. Our calculations show that the emergency actions taken by national energy authorities in response to that accident, though not necessarily optimal, have generally been appropriate and in line with international best practices: the additional costs incurred due to these measures are lower than the economic losses avoided thanks to these actions. Preferential treatment of specific consumer types in the case of repeated power outages remains an open policy question. - Highlights: ► We evaluate the response of energy authorities to a sudden electricity crisis. ► We combine two top-down economic methods and a bottom-up engineering approach. ► We estimate the value of lost electricity by hour, day type and season. ► The response of energy authorities turned out to be effective. ► Costs of emergency actions were lower than the economic losses avoided.

Overheating failure of superheater suspension tubes of a captive thermal power plant boiler

International Nuclear Information System (INIS)

Bhattacharya, Sova; Amir, Q.M.; Kannan, C.; Mahapatra, S.B.

2000-01-01

Failure of boiler tubes is the foremost cause of forced boiler outages. One of the predominant failure mechanism of boiler tubes is the stress rupture failure in the form of either short term overheating or long term overheating which are normally encountered in superheater and reheater sections working in the creep range. The strength of the boiler tube depends on the stress level as well on the temperature of exposure in the creep range. An increase in either can reduce the time to rupture. Time at the exposure temperature is an important factor based on which the failures are categorised as either short term or long term. Though there is no established time duration criteria demarcating the short or long term stress rupture failures, depending on the various manifestations on the failed samples, one can categorise the failure. This paper addresses one such stress rupture failure in the superheater section of a captive thermal power plant of a refinery. Multiple failures on the suspension coil of a superheater section was investigated for the cause of failure. Laboratory investigation of the failed sample involved visual inspection, dimensional measurements, chemical analysis of internal deposits and microstructural study. On the basis of these, the failure was attributed to deposition of trisodium phosphate carried over by the feed water into the superheater section resulting in chokage and increase in local operating hoop stresses of the tube. The ultimate failure was thus categorised as long term overheating failure. (author)

Radiographic evaluation of corrosion/erosion failures in pressure vessels and pipings in fertilizer industry

International Nuclear Information System (INIS)

Sinha, G.S.; Sahay, K.N.; Sundaram, K.V.; Banerji, K.C.

1977-01-01

The uses of radiography in combating the corrosion/erosion failures of pressure equipments used in the fertilizer industry are highlighted. Premature failures in fertilizer plants have proved to be very costly. One of the principal agencies responsible for such failures in process industry is corrosion/erosion. Radiography, when supplemented with other NDT-techniques, has been found to be ideal and highly useful method for on-stream inspection and evaluation of corrosion/erosion failures of pressure vessels and pipings. Three case-histories have been presented to illustrate the importance of radiography. (author)

Breast density in women with premature ovarian failure or postmenopausal women using hormone therapy: analytical cross-sectional study

Directory of Open Access Journals (Sweden)

Patrícia Magda Soares

Full Text Available CONTEXT AND OBJECTIVE: Studies on postmenopausal women have reported increased risk of breast cancer relating to the type and duration of hormone therapy (HT used. Women with premature ovarian failure (POF represent a challenge, since they require prolonged HT. Little is known about the impact of prolonged HT use on these women's breasts. This study aimed to evaluate the effects of one type of HT on the breast density of women with POF, compared with postmenopausal women. DESIGN AND SETTING: Cross-sectional study at the Department of Obstetrics and Gynecology, Universidade Estadual de Campinas (Unicamp. METHODS: 31 women with POF and 31 postmenopausal women, all using HT consisting of conjugated equine estrogen combined with medroxyprogesterone acetate, and matched according to HT duration, were studied. Mammography was performed on all subjects and was analyzed by means of digitization or Wolfe's classification, stratified into two categories: non-dense (N1 and P1 patterns and dense (P2 and Dy. RESULTS: No significant difference in breast density was found between the two groups through digitization or Wolfe's classification. From digitization, the mean breast density was 24.1% ± 14.6 and 18.1% ± 17.2 in the POF and postmenopausal groups, respectively (P = 0.15. Wolfe's classification identified dense breasts in 51.6% and 29.0%, respectively (P = 0.171. CONCLUSION: There was no difference in breast density between the women with POF and postmenopausal women, who had used HT for the same length of time. These results may help towards compliance with HT use among women with POF.

Hypogonadism and renal failure: An update.

Science.gov (United States)

Thirumavalavan, Nannan; Wilken, Nathan A; Ramasamy, Ranjith

2015-01-01

The prevalence of both hypogonadism and renal failure is increasing. Hypogonadism in men with renal failure carries with it significant morbidity, including anemia and premature cardiovascular disease. It remains unclear whether testosterone therapy can affect the morbidity and mortality associated with renal failure. As such, in this review, we sought to evaluate the current literature addressing hypogonadism and testosterone replacement, specifically in men with renal failure. The articles chosen for this review were selected by performing a broad search using Pubmed, Embase and Scopus including the terms hypogonadism and renal failure from 1990 to the present. This review is based on both primary sources as well as review articles. Hypogonadism in renal failure has a multifactorial etiology, including co-morbid conditions such as diabetes, hypertension, old age and obesity. Renal failure can lead to decreased luteinizing hormone production and decreased prolactin clearance that could impair testosterone production. Given the increasing prevalence of hypogonadism and the potential morbidity associated with hypogonadism in men with renal failure, careful evaluation of serum testosterone would be valuable. Testosterone replacement therapy should be considered in men with symptomatic hypogonadism and renal failure, and may ameliorate some of the morbidity associated with renal failure. Patients with all stages of renal disease are at an increased risk of hypogonadism that could be associated with significant morbidity. Testosterone replacement therapy may reduce some of the morbidity of renal failure, although it carries risk.

NEONATAL COMPLICATIONS OF PREMATURE RUPTURE OF MEMBRANES

Directory of Open Access Journals (Sweden)

F. Nili AA. Shams Ansari

2003-07-01

Full Text Available Premature rupture of membranes (PROM is one of the most common complications of pregnancy that has a major impact on neonatal outcomes. With respect to racial, nutritional and cultural differences between developed and developing countries, this study was conducted to detect the prevalence of neonatal complications following PROM and the role of the duration of rupture of membranes in producing morbidities and mortalities in these neonates in our hospital. Among 2357 pregnant women, we found 163 (6.91% cases of premature rupture of the fetal membranes in Tehran Vali-e-Asr Hospital during April 2001 to April 2002. Route of delivery was cesarean section in 65.6% of women. Urinary tract infection occured in 1.8%, maternal leukocytosis and fever in 20.2% and 5.5%, chorioamnionitis in 6.1%, fetal tachycardia in 1.2% and olygohydramnios in 4.9%. Gestational age in 138 (86% of neonates was less than 37 completed weeks. Thirty five infants (21.47% had respiratory distress syndrome and 33 (20.245% had clinical sepsis. Pneumonia in 6 (3.7% and skeletal deformity in 7 (4.294% were seen. Rupture of membrane of more than 24 hours duration occurred in 71 (43.6% of the patients. Comparison of morbidities between two groups of neonates and their mothers according to the duration of PROM (less and more than 24 hours showed significant differences in NICU admission, olygohydramnios, maternal fever, leukocytosis and chorioamnionitis rates (p24 hr of PROM with an odds ratio of 2.68 and 2.73, respectively. Positive blood and eye cultures were detected in 16 cases during 72 hours of age. Staphylococcus species, klebsiella, E.coli and streptococcus were the predominant organisms among positive blood cultures. Mortality was seen in 18 (11% of neonates because of respiratory failure, disseminated intravascular coagulation, septic shock, and a single case of congenital toxoplasmosis. In this study, the prevalence of prematurity, sepsis and prolonged rupture of membrane

Consequences of long-term power outages and high electricity prices lasting for months; Konsekvenser av langvarige stroemutfall og hoeye kraftpriser i flere maaneder

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-07-01

Several areas in the world have experienced electricity outages for longer periods of time, but the consequences of these are sparsely documented. There is a need for further analysis of the socioeconomic consequences of the outages. In addition to KILE (Quality adjusted revenue framework for un supplied energy) costs one has to take into account that the costs often increase proportionally with the durance of the outage, and that KILE tariffs do not reflect lost consumer's surplus for products that are not produced during an outage. A good example is the public underground transport, where the company's economical loss can be significantly smaller than the loss of utility value for the travellers. If the authorities act with reasonability it is difficult to see that periods with very high prices represent a big problem. The most important problems are related to diffused effects, especially for households with a weak economy. These problems can be solved with improved contractual forms (price guarantees) or by transfers to the households, without weakening the incentives for electricity economising (ml)

Outage performance analysis of underlay cognitive RF and FSO wireless channels

KAUST Repository

Ansari, Imran Shafique

2014-09-01

In this work, the outage performance analysis of a dual-hop transmission system composed of asymmetric radio frequency (RF) channel cascaded with a free-space optical (FSO) link is presented. For the RF link, an underlay cognitive network is considered where the secondary users share the spectrum with licensed primary users. Indoor femtocells act as a practical example for such networks. More specifically, it is assumed that the RF link applies power control to maintain the interference at the primary network below a predetermined threshold. While the RF channel is modeled by the Rayleigh fading distribution, the FSO link is modeled by a unified Gamma-Gamma turbulence distribution. The FSO link accounts for pointing errors and both types of detection techniques (i.e. heterodyne detection as well as intensity modulation/direct detection (IM/DD)). With this model, a new exact closed-form expression is derived for the outage probability of the end-To-end signal-To-noise ratio of these systems in terms of the Meijer\\'s G function and the Fox\\'s H functions under fixed amplify-and-forward relay scheme. All new analytical results are verified via computer-based Monte-Carlo simulations and are illustrated by some selected numerical results.

Premature infants' health at multiple induced pregnancy.

Directory of Open Access Journals (Sweden)

Chernenkov Yu.V.

2015-09-01

Full Text Available Objective: to define the risk factors adversely influencing prenatal development at premature birth at use of methods of assisted reproductive technology (ART; to estimate premature' infants health from multiple induced pregnancy according to Perinatal Center of Saratov for last 3 years. Material and Methods. Under supervision there were 139 pregnant women with application ART. 202 children (51 twins were born and 5 triplet babies, from them 83 premature infants born from multiple induced pregnancy have been analyzed. Results. The newborns examined by method ART, were distributed as follows: 22-28 weeks — 19 children; 29-32 weeks — 23; 33-36 weeks — 41. Asphyxia at birth was marked at all premature infants. Respiratory insufficiency at birth is revealed in 87,3% of cases. The most frequent pathologies in premature infants are revealed: neurologic infringements and bronchopulmonary pathology occured at all children, developmental anomaly — 33, 8%, retinopathies in premature infants — 26,5%. The mortality causes include: extreme immaturity, cerebral leukomalacia, IVN 3 degrees. Conclusion. The risk factors, premature birth at application of methods ART are revealed: aged primiparas, pharmacological influence, absence of physiological conditions of prenatal development; multifetation. The high percent of birth of children with ELBW and ULBW is revealed. RDCN with further BPD development, retinopathies in premature infants and CNS defeat is more often occured.

7 CFR 29.1050 - Prematurity.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Prematurity. 29.1050 Section 29.1050 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 92) § 29.1050 Prematurity. A condition of growth and development characteristic of the lower...

xidative Stress and Retinopathy of Prematurity

OpenAIRE

Ümeyye Taka Aydın; Hatip Aydın; Osman Çekiç

2014-01-01

Oxidative stress plays an important role in the etiology of retinopathy of prematurity. Insufficient antioxidant system and increased oxidative stress in premature infants lead to the development of the disease. Understanding the mechanism of oxidative stress and antioxidant system and the related signaling pathways contribute to the development of novel options for diagnosis and treatment of retinopathy of prematurity. The current review aimed to evaluate the relationship between ox...

Educational paper: Retinopathy of prematurity.

Science.gov (United States)

Casteels, Ingele; Cassiman, Catherine; Van Calster, Joachim; Allegaert, Karel

2012-06-01

Retinopathy of prematurity (ROP) is a proliferative retinal vascular disease affecting the premature infant with an incompletely vascularized retina. The spectrum of ophthalmological findings in ROP exists from minimal sequelae, which do not affect vision, to bilateral retinal detachment and total blindness. With the increased survival of very small infants, retinopathy of prematurity has become one of the leading causes of childhood blindness. Over the past two decades, major advances have been made in understanding the pathogenesis of ROP, to a large extent as a result of changes in clinical risk factors (oxygen and non-oxygen related) and characteristics observed in ROP cases. This article provides a literature review on the evolution in clinical characteristics, classification and treatment modalities and indications of ROP. Special attention is hereby paid to the neonatal factors influencing the development of ROP and to the necessity for everyone caring for premature babies to have a well-defined screening and treatment protocol for ROP. Such screening protocol needs to be based on a unit-specific ROP risk profile and, consequently, may vary between different European regions. Retinopathy of prematurity is an important cause of ocular morbidity and blindness in children. With better understanding of the pathogenesis, screening and treatment guidelines have changed over time and are unit specific.

Refractive status and optical components of premature babies with or without retinopathy of prematurity at 3-4 years old.

Science.gov (United States)

Ouyang, Li-Juan; Yin, Zheng-Qin; Ke, Ning; Chen, Xin-Ke; Liu, Qin; Fang, Jing; Chen, Lin; Chen, Xiu-Rong; Shi, Hui; Tang, Ling; Pi, Lian-Hong

2015-01-01

To investigate the refractive status and optical components of premature babies with or without retinopathy of prematurity (ROP) at 3-4 years old, and to explore the influence of prematurity and ROP on the refractive status and optical components. Premature babies receiving fundus examination were recruited into ROP group and non-ROP group, with age-matched full-term babies as controls. The incidence of myopia was the highest in ROP (3/59, 5.08%). The incidence of astigmatism was significantly different between ROP (37.29%, 22/59) and controls (17.86%, 15/84). The corneal refractive power in ROP and non-ROP was more potent compared with controls (PPremature babies with or without ROP are susceptible to myopia and astigmatism. ROP, prematurity and low birth-weight synergistically influence the development of refractive status and optical components, of which the prematurity and low birth-weight are more important.

The four ''Ps'' of outage management

International Nuclear Information System (INIS)

Kuehn, S.E.

1996-01-01

This article describes how planning, partnering, preparation and people prevent poor outage performance. Boasting the best production costs in a decade, the US fleet of nuclear reactors is performing better than ever. Industry wide, production costs fell 7% to $20.02 per net megawatt hour (MWh) and output climbed 3% to 634million MWh. It doesn't take a nuclear physicists to realize that when base-loaded nuclear units are operated for long periods of time, near their technical potential, costs will fall and relative performance improves. Statistics for 1994 compiled by the Institute of Nuclear Operations (INPO) and the World Association of Nuclear Operators (WANO) showed the industry has steadily improved in most of the 10 industry-recognized categories. In 1994, Unit Capability Factor (the percentage of maximum energy generation a plant can supply to the grid) reached just under 82%, beating the 1995 goal and proving just how far the industry has come (62.7% in 1980) when improving plant operations

Improvement of availability of PWR nuclear plants through the reduction of the time required for refueling/maintenance outages, Phase 1. Final report

International Nuclear Information System (INIS)

Thompson, C.A.

1978-08-01

The objective of this project is to identify improvements in procedures and equipment which will reduce the time required for refueling/maintenance outages at PWR nuclear power plants. The outage of Commonwealth Edison Zion Station Unit 1 in March through May of 1976 was evaluated to identify those items which caused delays and those work activities that offer the potential for significant improvements toward reducing its overall duration. Thus, the plant's availability for power production would be increased. Revisions in procedures and some equipment modifications were implemented and evaluated during the Zion Unit 2 refueling/maintenance outage beginning in January 1977. Analysis of the observed data has identified benefits available through improved refueling equipment and also areas where additional new, innovative refueling, or refueling-related equipment should be beneficial. A number of specific design concepts are recommended as a result of Phase 1. In addition, a new master planning mechanism is described for implementation during subsequent planned outages at Zion Station. This final report describes the recommended conceptual designs and planning mechanism and assesses their impact upon future outages. Their effect on savings in refueling time, labor, and radiation exposure is discussed. The estimated economic payoff for these concepts was found to be of such significance that an additional phase of the program is warranted. During this extended phase, a more detailed engineering study should be undertaken to determine the cost of implementation along with more specific estimates of the benefits for PWR plants already in operation or under construction

Assessment and Application of the ROSE Code for Reactor Outage Thermal-Hydraulic and Safety Analysis

International Nuclear Information System (INIS)

Liang, Thomas K.S.; Ko, F.-K.; Dai, L.-C.

2001-01-01

The currently available tools, such as RELAP5, RETRAN, and others, cannot easily and correctly perform the task of analyzing the system behavior during plant outages. Therefore, a medium-sized program aiming at reactor outage simulation and evaluation, such as midloop operation (MLO) with loss of residual heat removal (RHR), has been developed. Important thermal-hydraulic processes involved during MLO with loss of RHR can be properly simulated by the newly developed reactor outage simulation and evaluation (ROSE) code. The two-region approach with a modified two-fluid model has been adopted to be the theoretical basis of the ROSE code.To verify the analytical model in the first step, posttest calculations against the integral midloop experiments with loss of RHR have been performed. The excellent simulation capacity of the ROSE code against the Institute of Nuclear Energy Research Integral System Test Facility test data is demonstrated. To further mature the ROSE code in simulating a full-sized pressurized water reactor, assessment against the WGOTHIC code and the Maanshan momentary-loss-of-RHR event has been undertaken. The successfully assessed ROSE code is then applied to evaluate the abnormal operation procedure (AOP) with loss of RHR during MLO (AOP 537.4) for the Maanshan plant. The ROSE code also has been successfully transplanted into the Maanshan training simulator to support operator training. How the simulator was upgraded by the ROSE code for MLO will be presented in the future

An Efficient Simulation Scheme of the Outage Probability with Co-Channel Interference

KAUST Repository

Rached, Nadhir B.

2016-03-28

© 2015 IEEE. The outage probability (OP) of the signal-to-interference-plus-noise ratio (SINR) is an important metric used to evaluate the performance of wireless communication systems operating over fading channels. One major difficulty toward assessing the OP is that, in most of the realistic scenarios, closed-form expressions cannot be derived. This is for instance the case of Log-normal fading environments, in which evaluating the OP of the SINR amounts to computing the probability that a sum of correlated Log-normal variates exceeds a given threshold. Since such a probability is not known to admit a closed-form expression, it has thus far been evaluated by several approximation techniques, the accuracies of which are unfortunately not guaranteed in the interesting region of small outage probabilities. For these regions, simulation techniques based on variance reduction algorithms can represent a good alternative, being well-recognized to be quick and highly accurate for estimating rare event probabilities. This constitutes the major motivation behind our work. More specifically, we propose an efficient importance sampling approach which is based on a covariance matrix scaling technique and illustrate its computational gain over naive Monte Carlo simulations through some selected simulation results.

Nonparametric Tree-Based Predictive Modeling of Storm Outages on an Electric Distribution Network.

Science.gov (United States)

He, Jichao; Wanik, David W; Hartman, Brian M; Anagnostou, Emmanouil N; Astitha, Marina; Frediani, Maria E B

2017-03-01

This article compares two nonparametric tree-based models, quantile regression forests (QRF) and Bayesian additive regression trees (BART), for predicting storm outages on an electric distribution network in Connecticut, USA. We evaluated point estimates and prediction intervals of outage predictions for both models using high-resolution weather, infrastructure, and land use data for 89 storm events (including hurricanes, blizzards, and thunderstorms). We found that spatially BART predicted more accurate point estimates than QRF. However, QRF produced better prediction intervals for high spatial resolutions (2-km grid cells and towns), while BART predictions aggregated to coarser resolutions (divisions and service territory) more effectively. We also found that the predictive accuracy was dependent on the season (e.g., tree-leaf condition, storm characteristics), and that the predictions were most accurate for winter storms. Given the merits of each individual model, we suggest that BART and QRF be implemented together to show the complete picture of a storm's potential impact on the electric distribution network, which would allow for a utility to make better decisions about allocating prestorm resources. © 2016 Society for Risk Analysis.

Fast Outage Probability Simulation for FSO Links with a Generalized Pointing Error Model

KAUST Repository

Ben Issaid, Chaouki

2017-02-07

Over the past few years, free-space optical (FSO) communication has gained significant attention. In fact, FSO can provide cost-effective and unlicensed links, with high-bandwidth capacity and low error rate, making it an exciting alternative to traditional wireless radio-frequency communication systems. However, the system performance is affected not only by the presence of atmospheric turbulences, which occur due to random fluctuations in the air refractive index but also by the existence of pointing errors. Metrics, such as the outage probability which quantifies the probability that the instantaneous signal-to-noise ratio is smaller than a given threshold, can be used to analyze the performance of this system. In this work, we consider weak and strong turbulence regimes, and we study the outage probability of an FSO communication system under a generalized pointing error model with both a nonzero boresight component and different horizontal and vertical jitter effects. More specifically, we use an importance sampling approach which is based on the exponential twisting technique to offer fast and accurate results.

Outage performance of opportunistic two-way amplify-and-forward relaying with outdated channel state information

KAUST Repository

Hwang, Kyusung; Ju, Minchul; Alouini, Mohamed-Slim

2013-01-01

In this paper, we study the outage performance of an amplify-and-forward (AF)-based two-way relaying (TWR) system with multiple relays where a single relay selection is performed based on outdated channel state information (CSI). Specifically, we

Development of an Agent Based Model to Estimate and Reduce Time to Restoration of Storm Induced Power Outages

Science.gov (United States)

Walsh, T.; Layton, T.; Mellor, J. E.

2017-12-01

Storm damage to the electric grid impacts 23 million electric utility customers and costs US consumers $119 billion annually. Current restoration techniques rely on the past experiences of emergency managers. There are few analytical simulation and prediction tools available for utility managers to optimize storm recovery and decrease consumer cost, lost revenue and restoration time. We developed an agent based model (ABM) for storm recovery in Connecticut. An ABM is a computer modeling technique comprised of agents who are given certain behavioral rules and operate in a given environment. It allows the user to simulate complex systems by varying user-defined parameters to study emergent, unpredicted behavior. The ABM incorporates the road network and electric utility grid for the state, is validated using actual storm event recoveries and utilizes the Dijkstra routing algorithm to determine the best path for repair crews to travel between outages. The ABM has benefits for both researchers and utility managers. It can simulate complex system dynamics, rank variable importance, find tipping points that could significantly reduce restoration time or costs and test a broad range of scenarios. It is a modular, scalable and adaptable technique that can simulate scenarios in silico to inform emergency managers before and during storm events to optimize restoration strategies and better manage expectations of when power will be restored. Results indicate that total restoration time is strongly dependent on the number of crews. However, there is a threshold whereby more crews will not decrease the restoration time, which depends on the total number of outages. The addition of outside crews is more beneficial for storms with a higher number of outages. The time to restoration increases linearly with increasing repair time, while the travel speed has little overall effect on total restoration time. Crews traveling to the nearest outage reduces the total restoration time

Premature infant

Science.gov (United States)

... matter Infection or neonatal sepsis Low blood sugar (hypoglycemia) Neonatal respiratory distress syndrome, extra air in the tissue ... Outlook (Prognosis) Prematurity used to be a major cause of infant deaths. Improved medical and nursing techniques ...

Outage Performance Analysis of Relay Selection Schemes in Wireless Energy Harvesting Cooperative Networks over Non-Identical Rayleigh Fading Channels.

Science.gov (United States)

Do, Nhu Tri; Bao, Vo Nguyen Quoc; An, Beongku

2016-02-26

In this paper, we study relay selection in decode-and-forward wireless energy harvesting cooperative networks. In contrast to conventional cooperative networks, the relays harvest energy from the source's radio-frequency radiation and then use that energy to forward the source information. Considering power splitting receiver architecture used at relays to harvest energy, we are concerned with the performance of two popular relay selection schemes, namely, partial relay selection (PRS) scheme and optimal relay selection (ORS) scheme. In particular, we analyze the system performance in terms of outage probability (OP) over independent and non-identical (i.n.i.d.) Rayleigh fading channels. We derive the closed-form approximations for the system outage probabilities of both schemes and validate the analysis by the Monte-Carlo simulation. The numerical results provide comprehensive performance comparison between the PRS and ORS schemes and reveal the effect of wireless energy harvesting on the outage performances of both schemes. Additionally, we also show the advantages and drawbacks of the wireless energy harvesting cooperative networks and compare to the conventional cooperative networks.

77 FR 63757 - Extension of the Commission's Rules Regarding Outage Reporting to Interconnected Voice Over...

Science.gov (United States)

2012-10-17

... telephone subscriptions in the United States were users of interconnected VoIP providers--an increase of 21... Commission's Rules Regarding Outage Reporting to Interconnected Voice Over Internet Protocol Service Providers and Broadband Internet Service Providers AGENCY: Federal Communications Commission. ACTION: Final...

Outage performance improvement by state of the art reactor stud tensioning

International Nuclear Information System (INIS)

Oehler, Horst Werner; Vervliet, Herman

2006-01-01

Actual methods of reactor closing, i.e. cover to vessel sealing, is based on the creation of an equal load to the sealing circumference by tensioning all reactor studs with an equal force. This method ensures leak tightness through equal compression of the reactor seal in normal circumstances and is largely applied for all types of reactors throughout many generations and designs of nuclear power stations. The tension generated in each reactor stud is controlled indirectly by measuring the reactor stud elongation while under stress. Most studs are designed to measure this elongation easily by conventional or more advanced systems (from individual clock gauge to integrated digital transmission to a computer screen). It is this elongation value, prescribed by the reactor vessel/cover manufacturer which must be respected and demonstrated during all reactor closing operations, weather they take place for initial hydro testing, refuelling operations or periodical hydraulic tests of the primary circuit. Closing (and re-opening) of reactor vessels has become a routine operation as it is required for fuel reloading of the reactor core. This operation is performed on all PWR and BWR type of reactors with a large variety of tooling. As most of the utilities have implemented maintenance optimisation programs, the refuelling outage is reduced to a sequence of activities that allow quick and efficient refuelling of the core. The performance and efficiency of instrumentation and tooling deployed during these essential activities are of the utmost importance to minimise the critical path of the refuelling outage. Today, in support of outage performance, many utilities have invested in new and refurbished tooling to allow quick and efficient opening and closing of the reactor vessel. The features and properties of the most performing multi stud tensioning machines currently in service in nuclear power stations world wide (Africa, Europe, Asia and USA) are presented in the paper

Prematurity Affects Age of Presentation of Pyloric Stenosis.

Science.gov (United States)

Costanzo, Caitlyn M; Vinocur, Charles; Berman, Loren

2017-02-01

Term infants with hypertrophic pyloric stenosis (HPS) typically present between 4 and 6 weeks. There is limited consensus, however, regarding age of presentation of premature infants. We aim to determine if there is an association between the degree of prematurity and chronological age of presentation of HPS. A total of 2988 infants who had undergone a pyloromyotomy for HPS were identified from the 2012 and 2013 NSQIP-P Participant Use Files. Two hundred seventeen infants (7.3%) were born prematurely. A greater degree of prematurity was associated with an older chronological age of presentation ( P Prematurity was significantly associated with an increase in overall postoperative morbidity, reintubation, readmission, and postoperative length of stay. When clinicians evaluate an infant with nonbilious emesis with a history of prematurity, they should consider pyloric stenosis if the calculated postconceptional age is between 44 and 50 weeks. When counseling families of premature infants, surgeons should discuss the increased incidence of postpyloromyotomy morbidity.

Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1. Volume 5: Analysis of core damage frequency from seismic events for plant operational state 5 during a refueling outage

International Nuclear Information System (INIS)

Budnitz, R.J.; Davis, P.R.; Ravindra, M.K.; Tong, W.H.

1994-08-01

In 1989 the US Nuclear Regulatory Commission (NRC) initiated an extensive program to examine carefully the potential risks during low-power and shutdown operations. The program included two parallel projects, one at Sandia National Laboratories studying a boiling water reactor (Grand Gulf), and the other at Brookhaven National Laboratory studying a pressurized water reactor (Surry Unit 1). Both the Sandia and Brookhaven projects have examined only accidents initiated by internal plant faults---so-called ''internal initiators.'' This project, which has explored the likelihood of seismic-initiated core damage accidents during refueling outage conditions, is complementary to the internal-initiator analyses at Brookhaven and Sandia. This report covers the seismic analysis at Grand Gulf. All of the many systems modeling assumptions, component non-seismic failure rates, and human effort rates that were used in the internal-initiator study at Grand Gulf have been adopted here, so that the results of the study can be as comparable as possible. Both the Sandia study and this study examine only one shutdown plant operating state (POS) at Grand Gulf, namely POS 5 representing cold shutdown during a refueling outage. This analysis has been limited to work analogous to a level-1 seismic PRA, in which estimates have been developed for the core-damage frequency from seismic events during POS 5. The results of the analysis are that the core-damage frequency for earthquake-initiated accidents during refueling outages in POS 5 is found to be quite low in absolute terms, less than 10 -7 /year

Exact outage analysis of incremental decode-and-forward opportunistic relaying

KAUST Repository

Tourki, Kamel; Yang, Hongchuan; Alouini, Mohamed-Slim

2010-01-01

In this paper, we investigate a dual-hop decode-andforward opportunistic relaying scheme where the selected relay chooses to cooperate only if the source-destination channel is of an unacceptable quality. In our study, we derive exact closed-form expression for the outage probability based on the exact statistics of each hop. Furthermore, we perform asymptotic analysis and we deduce the diversity order of the scheme. We validate our analysis by showing that performance simulation results coincide with our analytical results over different network architectures. © 2010 IEEE.

Exact outage analysis of incremental decode-and-forward opportunistic relaying

KAUST Repository

Tourki, Kamel

2010-11-01

In this paper, we investigate a dual-hop decode-andforward opportunistic relaying scheme where the selected relay chooses to cooperate only if the source-destination channel is of an unacceptable quality. In our study, we derive exact closed-form expression for the outage probability based on the exact statistics of each hop. Furthermore, we perform asymptotic analysis and we deduce the diversity order of the scheme. We validate our analysis by showing that performance simulation results coincide with our analytical results over different network architectures. © 2010 IEEE.

Prematurity, atopy, and childhood asthma in Puerto Ricans.

Science.gov (United States)

Rosas-Salazar, Christian; Ramratnam, Sima K; Brehm, John M; Han, Yueh-Ying; Boutaoui, Nadia; Forno, Erick; Acosta-Pérez, Edna; Alvarez, María; Colón-Semidey, Angel; Canino, Glorisa; Celedón, Juan C

2014-02-01

Puerto Rican children share a disproportionate burden of prematurity and asthma in the United States. Little is known about prematurity and childhood asthma in Puerto Rican subjects. We sought to examine whether prematurity is associated with asthma in Puerto Rican children. We performed a case-control study of 678 children aged 6 to 14 years with (n = 351) and without (n = 327) asthma living in San Juan, Puerto Rico. Prematurity was defined by parental report for our primary analysis. In a secondary analysis, we only included children whose parents reported prematurity that required admission to the neonatal intensive care unit. Asthma was defined as physician-diagnosed asthma and wheeze in the prior year. We used logistic regression for analysis. All multivariate models were adjusted for age, sex, household income, atopy (≥1 positive IgE level to common allergens), maternal history of asthma, and early-life exposure to environmental tobacco smoke. In a multivariate analysis there was a significant interaction between prematurity and atopy on asthma (P = .006). In an analysis stratified by atopy, prematurity was associated with a nearly 5-fold increased odds of asthma in atopic children (adjusted odds ratio, 4.7; 95% CI, 1.5-14.3; P = .007). In contrast, there was no significant association between prematurity and asthma in nonatopic children. Similar results were obtained in our analysis of prematurity requiring admission to the neonatal intensive care unit and asthma. Our results suggest that atopy modifies the estimated effect of prematurity on asthma in Puerto Rican children. Prematurity might explain, in part, the high prevalence of atopic asthma in this ethnic group. Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

Using advanced tomography techniques to investigate the development of White Etching Cracks in a prematurely failed field bearing

Energy Technology Data Exchange (ETDEWEB)

Gould, Benjamin; Greco, Aaron; Stadler, Kenred; Vegter, Erik; Xiao, Xianghui

2017-12-01

Crack surrounded by areas of microstructural alteration deemed "White etching cracks" (WECs) lead to premature failures within a multitude applications. While the exact cause of these failures remains unknown, a large number of hypotheses exist as to how and why these cracks form. The aim of the current work is to study newly initiated WEC networks using X-ray tomography followed by selective sectioning, in an attempt to elucidate the formation mechanisms of these cracks. The results obtained show that, for the presented bearing, WECs form preferentially around multi-phase inclusions containing aluminum, manganese, and sulfur. Additionally the results support the idea that the microstructural alterations form secondary to any cracking, suggesting that the alterations are simply a symptom of a preexisting failure.

Surfactant proteins gene variants in premature newborn infants with severe respiratory distress syndrome.

Science.gov (United States)

Somaschini, Marco; Presi, Silvia; Ferrari, Maurizio; Vergani, Barbara; Carrera, Paola

2017-12-19

Genetic surfactant dysfunction causes respiratory failure in term and near-term newborn infants, but little is known of such condition in prematures. We evaluated genetic surfactant dysfunction in premature newborn infants with severe RDS. A total of 68 preterm newborn infants with gestational age ≤32 weeks affected by unusually severe RDS were analysed for mutations in SFTPB, SFTPC and ABCA3. Therapies included oxygen supplementation, nasal CPAP, different modalities of ventilatory support, administration of exogenous surfactant, inhaled nitric oxide and steroids. Molecular analyses were performed on genomic DNA extracted from peripheral blood and Sanger sequencing of whole gene coding regions and intron junctions. In one case histology and electron microscopy on lung tissue was performed. Heterozygous previously described rare or novel variants in surfactant proteins genes ABCA3, SFTPB and SFTPC were identified in 24 newborn infants. In total, 11 infants died at age of 2 to 6 months. Ultrastructural analysis of lung tissue of one infant showed features suggesting ABCA3 dysfunction. Rare or novel genetic variants in genes encoding surfactant proteins were identified in a large proportion (35%) of premature newborn infants with particularly severe RDS. We speculate that interaction of developmental immaturity of surfactant production in association with abnormalities of surfactant metabolism of genetic origin may have a synergic worsening phenotypic effect.

Outage analysis for underlay relay-assisted cognitive networks

KAUST Repository

Tourki, Kamel; Qaraqe, Khalid A.; Alouini, Mohamed-Slim

2012-01-01

Cooperative relay technology was recently introduced into cognitive radio networks in order to enhance network capacity, scalability, and reliability of end-to-end communication. In this paper, we investigate an underlay cognitive network where the quality of service of the secondary link is maintained by triggering an opportunistic regenerative relaying once it falls under an unacceptable level. We first provide the exact cumulative density function (CDF) of received signal-to-noise (SNR) over each hop with co-located relays. Then, the CDFs are used to determine very accurate closed-form expression for the outage probability for a transmission rate R. We validate our analysis by showing that simulation results coincide with our analytical results in Rayleigh fading channels. © 2012 IEEE.

Outage analysis for underlay relay-assisted cognitive networks

KAUST Repository

Tourki, Kamel

2012-12-01

Cooperative relay technology was recently introduced into cognitive radio networks in order to enhance network capacity, scalability, and reliability of end-to-end communication. In this paper, we investigate an underlay cognitive network where the quality of service of the secondary link is maintained by triggering an opportunistic regenerative relaying once it falls under an unacceptable level. We first provide the exact cumulative density function (CDF) of received signal-to-noise (SNR) over each hop with co-located relays. Then, the CDFs are used to determine very accurate closed-form expression for the outage probability for a transmission rate R. We validate our analysis by showing that simulation results coincide with our analytical results in Rayleigh fading channels. © 2012 IEEE.

Conceptualizing pathways linking women's empowerment and prematurity in developing countries.

Science.gov (United States)

Afulani, Patience A; Altman, Molly; Musana, Joseph; Sudhinaraset, May

2017-11-08

Globally, prematurity is the leading cause of death in children under the age of 5. Many efforts have focused on clinical approaches to improve the survival of premature babies. There is a need, however, to explore psychosocial, sociocultural, economic, and other factors as potential mechanisms to reduce the burden of prematurity. Women's empowerment may be a catalyst for moving the needle in this direction. The goal of this paper is to examine links between women's empowerment and prematurity in developing settings. We propose a conceptual model that shows pathways by which women's empowerment can affect prematurity and review and summarize the literature supporting the relationships we posit. We also suggest future directions for research on women's empowerment and prematurity. The key words we used for empowerment in the search were "empowerment," "women's status," "autonomy," and "decision-making," and for prematurity we used "preterm," "premature," and "prematurity." We did not use date, language, and regional restrictions. The search was done in PubMed, Population Information Online (POPLINE), and Web of Science. We selected intervening factors-factors that could potentially mediate the relationship between empowerment and prematurity-based on reviews of the risk factors and interventions to address prematurity and the determinants of those factors. There is limited evidence supporting a direct link between women's empowerment and prematurity. However, there is evidence linking several dimensions of empowerment to factors known to be associated with prematurity and outcomes for premature babies. Our review of the literature shows that women's empowerment may reduce prematurity by (1) preventing early marriage and promoting family planning, which will delay age at first pregnancy and increase interpregnancy intervals; (2) improving women's nutritional status; (3) reducing domestic violence and other stressors to improve psychological health; and (4) improving

Assessment of hormonal activity in patients with premature ejaculation

Directory of Open Access Journals (Sweden)

Lütfi Canat

Full Text Available ABSTRACT Purpose Premature ejaculation is considered the most common type of male sexual dysfunction. Hormonal controls of ejaculation have not been exactly elucidated. The aim of our study is to investigate the role of hormonal factors in patients with premature ejaculation. Materials and Methods Sixty-three participants who consulted our outpatient clinics with complaints of premature ejaculation and 39 healthy men as a control group selected from volunteers were included in the study. A total of 102 sexual active men aged between 21 and 76 years were included. Premature ejaculation diagnostic tool questionnaires were used to assessment of premature ejaculation. Serum levels of follicle stimulating hormone, luteinizing hormone, prolactin, total and free testosterone, thyroid-stimulating hormone, free triiodothyronine and thyroxine were measured. Results Thyroid-stimulating hormone, luteinizing hormone, and prolactin levels were significantly lower in men with premature ejaculation according to premature ejaculation diagnostic tool (p=0.017, 0.007 and 0.007, respectively. Luteinizing hormone level (OR, 1.293; p=0.014 was found to be an independent risk factor for premature ejaculation. Conclusions Luteinizing hormone, prolactin, and thyroid-stimulating hormone levels are associated with premature ejaculation which was diagnosed by premature ejaculation diagnostic tool questionnaires. The relationship between these findings have to be determined by more extensive studies.

Prevalence of premature ovarian failure in systemic lupus erythematosus patients treated with immunosuppressive agents in Thailand.

Science.gov (United States)

Akawatcharangura, P; Taechakraichana, N; Osiri, M

2016-04-01

Systemic lupus erythematosus (SLE) is an autoimmune disease that affects most women of reproductive age. The prevalence of premature ovarian failure (POF) in SLE patients is higher than that in the general population. However, the data on this condition are limited in Asian countries. To determine the prevalence and associated factors of POF in SLE patients who received immunosuppressive therapy. Women aged 18-40 years who were diagnosed with SLE according to the 1997 revised criteria for the classification of SLE or patients with biopsy-proven lupus nephritis were evaluated. All patients had received at least one of the following immunosuppressive agents: cyclophosphamide (CYC), azathioprine, mycophenolate mofetil, chlorambucil or cyclosporine for more than six months. POF was diagnosed in those who had sustained amenorrhea for more than six consecutive months, with a level of estradiol ≤ 110 pmol/L (30 pg/mL) and follicle stimulating hormone ≥40 IU/L. Ninety two SLE patients were included in this study. Mean age at enrollment was 30 ± 6.9 years and disease duration was 103 ± 67.5 months. The mean Systemic Lupus International Collaborating Clinics/ American College of Rheumatology (SLICC/ACR) damage index was 1.7 ± 1.7. Seventy five patients (82%) had lupus nephritis. Sixty four patients (70%) received CYC. Eleven patients (12%) with POF were observed. For the binary logistic regression model, CYC cumulative dosage of more than 10 g was the only independent risk factor of POF (hazard ratio 17.0, 95% CI 1.96-147.72, p = 0.01). From our data, 12% of SLE patients developed POF. A cumulative dose of CYC of more than 10 g was the only risk factor for POF. To prevent these events, systematic evaluation and early recognition of POF should be promoted in the care of SLE patients. © The Author(s) 2015.

Premature Ejaculation

Science.gov (United States)

... include the following: Anxiety about performance Guilty feelings Depression Stress Relationship problems Men who have a low amount of a special ... on your favorite sports team. Psychological assistance Anxiety, depression ... may help men who have premature ejaculation. Some antidepressants seem to ...

A Short-Term Outage Model of Wind Turbines with Doubly Fed Induction Generators Based on Supervisory Control and Data Acquisition Data

Directory of Open Access Journals (Sweden)

Peng Sun

2016-10-01

Full Text Available This paper presents a short-term wind turbine (WT outage model based on the data collected from a wind farm supervisory control and data acquisition (SCADA system. Neural networks (NNs are used to establish prediction models of the WT condition parameters that are dependent on environmental conditions such as ambient temperature and wind speed. The prediction error distributions are discussed and used to calculate probabilities of the operation of protection relays (POPRs that were caused by the threshold exceedance of the environmentally sensitive parameters. The POPRs for other condition parameters are based on the setting time of the operation of protection relays. The union probability method is used to integrate the probabilities of operation of each protection relay to predict the WT short term outage probability. The proposed method has been used for real 1.5 MW WTs with doubly fed induction generators (DFIGs. The results show that the proposed method is more effective in WT outage probability prediction than traditional methods.

Some technical implications of Klein's concept of 'premature ego development'.

Science.gov (United States)

Mitrani, Judith L

2007-08-01

In this paper, the author revisits the problem of 'premature ego development' first introduced by Melanie Klein in 1930. She also highlights several developments in post-Kleinian thinking since the publication of that paper, which can be seen as offshoots of or complements to Klein's work. The author proposes a link between this category of precocious development and the absence of the experience of what Bion termed the 'containing object.' She puts forward several technical considerations relevant to analytic work with patients who suffer as a result of early developmental failures and presents various clinical vignettes in order to demonstrate the ways in which these considerations take shape in the analytic setting.

Worldwide OMEGA and Very Low Frequency (VLF) Transmitter Outages, January to December 1980.

Science.gov (United States)

1981-05-01

WORLDWIDE OMEGA AND VERY LOW FREQUENCY IVLF) TRANSMITTER OUTAGE--ETC, MAY 81 L RZONCA ,’,L.ASSI LED FAA-CT-81-26 FAA-RD- B1 -29 UL7 A-I’ l15FDRL AIO...computer for the time period GBR - Rugby , England (16.00 kHz) January to December 1980. (For the purposes of this report, any downtime NA - Cutler, Maine

Acute appendicitis in a premature baby

International Nuclear Information System (INIS)

Beluffi, Giampiero; Alberici, Elisa

2002-01-01

A case of acute appendicitis in a premature baby in whom diagnosis was suggested on plain films of the abdomen is presented. In this baby air in a hollow viscus suspected of being an enlarged appendix was the clue to diagnosis. The diagnostic dilemma of this rare and life-threatening condition in premature babies and newborns is underlined. The relevance of different imaging modalities and of different findings in this age group is discussed. Awareness of this rare condition and possible differential diagnosis in newborns and premature babies is stressed. (orig.)

Fundamental Limits of Parallel Optical Wireless Channels: Capacity Results and Outage Formulation

KAUST Repository

Chaaban, Anas; Rezki, Zouheir; Alouini, Mohamed-Slim

2016-01-01

Multi-channel (MC) optical wireless communication (OWC) systems employing wave-division multiplexing for outdoors free-space optical communications, or multi-user timedivision multiple access for indoors visible-light communications, e.g., can be modeled as parallel channels. Multi-input multioutput OWC systems can also be transformed, possibly with some performance loss, to parallel channels using pre-/postcoding. Studying the performance of such MC-OWC systems requires characterizing the capacity of the underlying parallel channels. In this paper, upper and lower bounds on the capacity of constant parallel OWC channels with a total average intensity constraint are derived. Then, the paper focuses on finding intensity allocations that maximize the lower bounds given channel-state information at the transmitter (CSIT). Due to its nonconvexity, the KKT conditions are used to describe a list of candidate allocations. Instead searching exhaustively for the best solution, low-complexity near-optimal algorithms are proposed. The resulting optimized lower bound nearly coincides with capacity at high signal-to-noise ratio (SNR). Under a quasi-static channel model and in the absence of CSIT, outage probability upper and lower bounds are derived. Those bounds also meet at high SNR, thus characterizing the outage capacity in this regime. Finally, the results are extended to a system with both average and peak intensity constraints.

Fundamental Limits of Parallel Optical Wireless Channels: Capacity Results and Outage Formulation

KAUST Repository

Chaaban, Anas

2016-10-26

Multi-channel (MC) optical wireless communication (OWC) systems employing wave-division multiplexing for outdoors free-space optical communications, or multi-user timedivision multiple access for indoors visible-light communications, e.g., can be modeled as parallel channels. Multi-input multioutput OWC systems can also be transformed, possibly with some performance loss, to parallel channels using pre-/postcoding. Studying the performance of such MC-OWC systems requires characterizing the capacity of the underlying parallel channels. In this paper, upper and lower bounds on the capacity of constant parallel OWC channels with a total average intensity constraint are derived. Then, the paper focuses on finding intensity allocations that maximize the lower bounds given channel-state information at the transmitter (CSIT). Due to its nonconvexity, the KKT conditions are used to describe a list of candidate allocations. Instead searching exhaustively for the best solution, low-complexity near-optimal algorithms are proposed. The resulting optimized lower bound nearly coincides with capacity at high signal-to-noise ratio (SNR). Under a quasi-static channel model and in the absence of CSIT, outage probability upper and lower bounds are derived. Those bounds also meet at high SNR, thus characterizing the outage capacity in this regime. Finally, the results are extended to a system with both average and peak intensity constraints.

Comparative study of visual functions in premature pre-school children with and without retinopathy of prematurity

Directory of Open Access Journals (Sweden)

Lígia Beatriz Bonotto

2014-01-01

Full Text Available Purpose: Observe whether there are differences in visual functions among premature infants with treated retinopathy of prematurity (ROP in relation to preterm infants with ROP and spontaneous regression; and among these two groups with ROP and the control group without ROP. Methods: Crosssectional observational no blind study. Premature infants were born between 06/199206/2006 and were exam between 06/200912/2010; registered in data of Hospital de Olhos Sandalla Amin Ghanem; with gestational age less than or equal to 32 weeks and 1,599 g born weigh; without ROP and ROP stages II or III, in one of the eyes, with spontaneous regression or with treatment; at least three visits during the selection period at maximum 6 months in the first exam and minimum 4 years of age in reassessment (chronological age were include. Premature that did not respond or were not located for reassessment and those that did not have conditions to do the exams were exclude. Study's groups: G1 ROP posttreatment; G2ROP postspontaneous regression; G3 without ROP (control. Visual function evaluated with visual acuity (VA, contrast sensitivity test (CST, color test (CT, eye movement, stereopsis. Results: Overall, there were 24 premature infants and 48 eyes. Normal VA: 64.28% (G1, 87.5% (G2 and 100% (G3; Normal CST: 66.67% (G1, 100% (G2 and 55.56% (G3; Normal Ishihara CT: 100% (G1 and G2 and 86% (G3; Normal Farnsworth CT: 20% (G1, 75% (G2 and 50% (G3. Normal stereoacuity: 0.00% (G1; 25% (G2 and 3.5% (G3. Strabismus: 37% (G2, 0.00% (G1 and G3. The prevalent tendency for lower response in CST and CT between the premature children in group G3 and Farnsworth color test in G1 is a curious result of this work and more study is necessary about these visual functions in older premature children. Conclusion: The visual functions showed no statistically significant difference among the groups studied.

Outage Performance Analysis of Relay Selection Schemes in Wireless Energy Harvesting Cooperative Networks over Non-Identical Rayleigh Fading Channels †

Science.gov (United States)

Do, Nhu Tri; Bao, Vo Nguyen Quoc; An, Beongku

2016-01-01

In this paper, we study relay selection in decode-and-forward wireless energy harvesting cooperative networks. In contrast to conventional cooperative networks, the relays harvest energy from the source’s radio-frequency radiation and then use that energy to forward the source information. Considering power splitting receiver architecture used at relays to harvest energy, we are concerned with the performance of two popular relay selection schemes, namely, partial relay selection (PRS) scheme and optimal relay selection (ORS) scheme. In particular, we analyze the system performance in terms of outage probability (OP) over independent and non-identical (i.n.i.d.) Rayleigh fading channels. We derive the closed-form approximations for the system outage probabilities of both schemes and validate the analysis by the Monte-Carlo simulation. The numerical results provide comprehensive performance comparison between the PRS and ORS schemes and reveal the effect of wireless energy harvesting on the outage performances of both schemes. Additionally, we also show the advantages and drawbacks of the wireless energy harvesting cooperative networks and compare to the conventional cooperative networks. PMID:26927119

On the sum of Gamma-Gamma variates with application to the fast outage probability evaluation over fading channels

KAUST Repository

Ben Issaid, Chaouki

2017-04-01

The Gamma-Gamma distribution has recently emerged in a number of applications ranging from modeling scattering and reverbation in sonar and radar systems to modeling atmospheric turbulence in wireless optical channels. In this respect, assessing the outage probability achieved by some diversity techniques over this kind of channels is of major practical importance. In many circumstances, this is intimately related to the difficult question of analyzing the statistics of a sum of Gamma-Gamma random variables. Answering this question is not a simple matter. This is essentially because outage probabilities encountered in practice are often very small, and hence the use of classical Monte Carlo methods is not a reasonable choice. This lies behind the main motivation of the present work. In particular, this paper proposes a new approach to estimate the left tail of the sum of independent and identically distributed Gamma-Gamma variates. More specifically, we propose a mean-shift importance sampling scheme that efficiently evaluates the outage probability of L-branch maximum ratio combining diversity receivers over Gamma-Gamma fading channels. The proposed estimator satisfies the well-known bounded relative error criterion. We show the accuracy and the efficiency of our approach compared to naive Monte Carlo via some selected numerical simulations.

On the sum of Gamma-Gamma variates with application to the fast outage probability evaluation over fading channels

KAUST Repository

Ben Issaid, Chaouki; Rached, Nadhir B.; Kammoun, Abla; Alouini, Mohamed-Slim; Tempone, Raul

2017-01-01

The Gamma-Gamma distribution has recently emerged in a number of applications ranging from modeling scattering and reverbation in sonar and radar systems to modeling atmospheric turbulence in wireless optical channels. In this respect, assessing the outage probability achieved by some diversity techniques over this kind of channels is of major practical importance. In many circumstances, this is intimately related to the difficult question of analyzing the statistics of a sum of Gamma-Gamma random variables. Answering this question is not a simple matter. This is essentially because outage probabilities encountered in practice are often very small, and hence the use of classical Monte Carlo methods is not a reasonable choice. This lies behind the main motivation of the present work. In particular, this paper proposes a new approach to estimate the left tail of the sum of independent and identically distributed Gamma-Gamma variates. More specifically, we propose a mean-shift importance sampling scheme that efficiently evaluates the outage probability of L-branch maximum ratio combining diversity receivers over Gamma-Gamma fading channels. The proposed estimator satisfies the well-known bounded relative error criterion. We show the accuracy and the efficiency of our approach compared to naive Monte Carlo via some selected numerical simulations.

Inducement of IGA/SCC in Inconel 600 steam generator tubing during unit outages

Energy Technology Data Exchange (ETDEWEB)

Durance, D.; Sedman, K. [Bruce Power, Tiverton, Ontario (Canada); Roberts, J. [CANTECH Associates Ltd., Burlington, Ontario (Canada); King, P. [Babcock and Wilcox Canada, Cambridge, Ontario (Canada); Gorman, J. [Dominion Engineering, Reston, VA (United States); Allen, R. [Kinectrics, Inc., Toronto, Ontario (Canada)

2008-07-01

The degradation of Unit 4 SG tubing by IGA/SCC has limited both the operating period and end of life predictions for Unit 4 since restart in late 2003. The circumferential IGA/SCC has been most significant in SG4 with substantial increases in both initiation and growth rates from 2005 through the spring of 2007. A detailed review of the occurrence of circumferential OD IGA/SCC at the RTZ in the HL TTS region of Bruce 4 steam generator tubes has led a conclusion that it is probable that the IGA/SCC has been the result of attack by partially reduced sulfur species such as tetrathionates and thiosulfates during periods of low temperature exposure. It is believed that attack of this type has mostly likely occurred during startup evolutions following outages as the result the development of aggressive reduced sulfur species in the TTS region during periods when the boilers were fully drained for maintenance activities. The modification of outage practices to limit secondary side oxygen ingress in the spring of 2007 has apparently arrested the degradation and has had significant affects on the allowable operating interval and end of life predictions for the entire unit. (author)

Inducement of IGA/SCC in Inconel 600 steam generator tubing during unit outages

International Nuclear Information System (INIS)

Durance, D.; Sedman, K.; Roberts, J.; King, P.; Gorman, J.; Allen, R.

2008-01-01

The degradation of Unit 4 SG tubing by IGA/SCC has limited both the operating period and end of life predictions for Unit 4 since restart in late 2003. The circumferential IGA/SCC has been most significant in SG4 with substantial increases in both initiation and growth rates from 2005 through the spring of 2007. A detailed review of the occurrence of circumferential OD IGA/SCC at the RTZ in the HL TTS region of Bruce 4 steam generator tubes has led a conclusion that it is probable that the IGA/SCC has been the result of attack by partially reduced sulfur species such as tetrathionates and thiosulfates during periods of low temperature exposure. It is believed that attack of this type has mostly likely occurred during startup evolutions following outages as the result the development of aggressive reduced sulfur species in the TTS region during periods when the boilers were fully drained for maintenance activities. The modification of outage practices to limit secondary side oxygen ingress in the spring of 2007 has apparently arrested the degradation and has had significant affects on the allowable operating interval and end of life predictions for the entire unit. (author)

Calculation of the Incremental Conditional Core Damage Probability on the Extension of Allowed Outage Time

International Nuclear Information System (INIS)

Kang, Dae Il; Han, Sang Hoon

2006-01-01

RG 1.177 requires that the conditional risk (incremental conditional core damage probability and incremental conditional large early release probability: ICCDP and ICLERP), given that a specific component is out of service (OOS), be quantified for a permanent change of the allowed outage time (AOT) of a safety system. An AOT is the length of time that a particular component or system is permitted to be OOS while the plant is operating. The ICCDP is defined as: ICCDP = [(conditional CDF with the subject equipment OOS)- (baseline CDF with nominal expected equipment unavailabilities)] [duration of the single AOT under consideration]. Any event enabling the component OOS can initiate the time clock for the limiting condition of operation for a nuclear power plant. Thus, the largest ICCDP among the ICCDPs estimated from any occurrence of the basic events for the component fault tree should be selected for determining whether the AOT can be extended or not. If the component is under a preventive maintenance, the conditional risk can be straightforwardly calculated without changing the CCF probability. The main concern is the estimations of the CCF probability because there are the possibilities of the failures of other similar components due to the same root causes. The quantifications of the risk, given that a subject equipment is in a failed state, are performed by setting the identified event of subject equipment to TRUE. The CCF probabilities are also changed according to the identified failure cause. In the previous studies, however, the ICCDP was quantified with the consideration of the possibility of a simultaneous occurrence of two CCF events. Based on the above, we derived the formulas of the CCF probabilities for the cases where a specific component is in a failed state and we presented sample calculation results of the ICCDP for the low pressure safety injection system (LPSIS) of Ulchin Unit 3

Use of workstations in the ANAV outage tasks course access

International Nuclear Information System (INIS)

Gómez Rodriguez, Carlos A.

2016-01-01

The access course for the Asco and Vandellos II Nuclear Power Plants contains all of the training that is considered necessary in compliance with the stipulations of current legislation for the pupils to carry out their activity at the plants. Given the heterogeneity of the special characteristics of those workers who take part in the outage tasks at our plants we have sought to improve the learning values of their access course with the inclusion of Work Stations since 2013. Several changes have been made in the training action since that date to make it more interactive.

76 FR 36892 - Proposed Extension of Part 4 of the Commission's Rules Regarding Outage Reporting to...

Science.gov (United States)

2011-06-23

...: None. Title: Communications Outage Reporting for Interconnected Voice over Internet Protocol Service.... Type of Review: New collection. Respondents: Businesses (Interconnected Voice over Internet Protocol... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 4 [PS Docket No. 11-82; FCC 11-74] Proposed...

Association between human breast milk and retinopathy of prematurity.

Science.gov (United States)

Fonseca, Luciana Teixeira; Senna, Denise C; Eckert, Gabriela Unchalo; Silveira, Rita de Cássia; Procianoy, Renato Soibelmann

2018-04-01

To evaluate the possible protective effect of breast milk against retinopathy of prematurity by comparing the amount of breast milk received by patients who developed retinopathy of prematurity and those who did not and to determine both the required minimum amount of breast milk and the time of life during which neonates need to receive breast milk for this effect to be significant. Cohort study of newborns with a birth weight of prematurity of any degree was 31% (100 of 323 patients) and that of severe retinopathy of prematurity was of 9% (29 of 323 patients). The median amounts of breast milk received daily by patients with and without retinopathy of prematurity were 4.9 mL/kg (interquartile range, 0.3-15.4) and 10.2 mL/kg (1.5-25.5), respectively. The amount of breast milk received in the first 6 weeks of life was inversely associated with the incidence of both retinopathy of prematurity of any degree and severe retinopathy of prematurity in the univariate analyses. However, the statistical significance was maintained only during the sixth week of life in a per-period multivariate analysis controlling for confounding factors. Small amounts of breast milk are inadequate to prevent retinopathy of prematurity in premature newborns at risk for the disease.

A new way of thinking about complications of prematurity.

Science.gov (United States)

Moore, Tiffany A; Berger, Ann M; Wilson, Margaret E

2014-01-01

The morbidity and mortality of preterm infants are impacted by their ability to maintain physiologic homeostasis using metabolic, endocrine, and immunologic mechanisms independent of the mother's placenta. Exploring McEwen's allostatic load model in preterm infants provides a new way to understand the altered physiologic processes associated with frequently occurring complications of prematurity such as bronchopulmonary dysplasia, intraventricular hemorrhage, necrotizing enterocolitis, and retinopathy of prematurity. The purpose of this article is to present a new model to enhance understanding of the altered physiologic processes associated with complications of prematurity. The model of allostatic load and complications of prematurity was derived to explore the relationship between general stress of prematurity and complications of prematurity. The proposed model uses the concepts of general stress of prematurity, allostasis, physiologic response patterns (adaptive-maladaptive), allostatic load, and complications of prematurity. These concepts are defined and theoretical relationships in the proposed model are interpreted using the four maladaptive response patterns of repeated hits, lack of adaptation, prolonged response, and inadequate response. Empirical evidence for cortisol, inflammation, and oxidative stress responses are used to support the theoretical relationships. The proposed model provides a new way of thinking about physiologic dysregulation in preterm infants. The ability to describe and understand complex physiologic mechanisms involved in complications of prematurity is essential for research. Advancing the knowledge of complications of prematurity will advance clinical practice and research and lead to testing of interventions to reduce negative outcomes in preterm infants.

International Context Regarding Application of Single Failure Criterion For New Reactors

International Nuclear Information System (INIS)

Basic, I.; Vrbanic, I.

2016-01-01

The Single Failure Criterion (SFC) ensures reliable performance of safety systems in nuclear power plants in response to design basis initiating events. The SFC, basically, requires that the system must be capable of performing its task in the presence of any single failure. The capability of a system to perform its design function in the presence of a single failure could be threatened by a common cause failure such as a fire, flood, or human intervention or by any other cause with potential to induce multiple failures. When applied to plant's response to a postulated design-basis initiating event, the SFC usually represents a requirement that particular safety system performs its safety functions as designed under the conditions which can include: All failures caused by a single failure; All identifiable but non-detectable failures, including those in the non-tested components; All failures and spurious system actions that cause (or are caused by) the postulated event. The paper provides an overview of the regulatory design requirements for new reactors addressing Single Failure Criterion (SFC) in accordance to international best-practices, particularly considering the SCF relation to in-service testing, maintenance, repair, inspection and monitoring of systems, structures and components important to safety. The paper discusses the comparison of the current SFC requirements and guidelines published by the IAEA, WENRA, EUR and nuclear regulators in the United States, United Kingdom, Russia, Korea, Japan, China and Finland. Also, paper addresses the application of SFC requirements in design; considerations for testing, maintenance, repair, inspection and monitoring; allowable equipment outage times; exemptions to SFC requirements; and analysis for SFC application to two-, three- and four-train systems and applications for small and modular reactors. (author).

Premature Epiphyseal Closure of the Lower Extremities Contributing to Short Stature after cis-Retinoic Acid Therapy in Medulloblastoma: A Case Report.

Science.gov (United States)

Noyes, Jessica J; Levine, Michael A; Belasco, Jean B; Mostoufi-Moab, Sogol

2016-01-01

Prolonged cis-retinoic acid (RA) exposure contributes to premature epiphyseal closure. cis-RA is administered in various treatment regimens for pediatric cancers, thus increasing the risk for bone deformities and compromised growth. We present a case of premature epiphyseal closure in a 9-year-old female with a history of medulloblastoma and treatment with a multimodal regimen including cis-RA. She was subsequently diagnosed with radiation-induced endocrine late effects including hypothyroidism and growth hormone deficiency (GHD). Seven months after initiation of GH therapy, an increased prominence of the wrists and knees combined with a deceleration in growth velocity prompted further evaluation; radiographs revealed bilateral premature closure of the distal femur and proximal tibia growth plates despite normal left wrist bone age. High doses of vitamin A and its analogs are linked to premature closure of the lower-extremity growth plates in animals and children. Pediatric brain tumor patients are at increased risk of growth failure due to concurrent radiation-induced GHD, damage to the spinal bones, and cis-RA-associated premature closure of the lower-extremity growth plates, with significant reduction in adult stature. A better appreciation of the detrimental effect of cis-RA on the growing skeleton is needed to monitor at-risk patients and to provide timely interventions. © 2015 S. Karger AG, Basel.

Retinopathy of prematurity

International Nuclear Information System (INIS)

Benavides Vargas, Ana Maria

2013-01-01

Retinopathy of prematurity has been the leading cause of childhood blindness. Early and effective screening has helped to diagnose the visual target of an infant by the difference between growing up with a disability or not. A joint effort between ophthalmologists and neonatologists is proposed to control this disease, ensuring success. An appropriate, early, effective and timely treatment has been the laser and cryotherapy like good choices for the neonate to prevent disease progression. Evaluation of screening program, to determine the incidence, compare statistics variables have been measures as other medical pathologies should be encouraged as research topics. A decrease in the incidence of retinopathy of prematurity is expected, controlling the risk factors during the child's stay in intrahospital neonatal unit [es

Prematurely terminated slug tests

International Nuclear Information System (INIS)

Karasaki, K.

1990-07-01

A solution of the well response to a prematurely terminated slug test (PTST) is presented. The advantages of a PTST over conventional slug tests are discussed. A systematized procedure of a PTST is proposed, where a slug test is terminated in the midpoint of the flow point, and the subsequent shut-in data is recorded and analyzed. This method requires a downhole shut-in device and a pressure transducer, which is no more than the conventional deep-well slug testing. As opposed to slug tests, which are ineffective when a skin is present, more accurate estimate of formation permeability can be made using a PTST. Premature termination also shortens the test duration considerably. Because in most cases no more information is gained by completing a slug test to the end, the author recommends that conventional slug tests be replaced by the premature termination technique. This study is part of an investigation of the feasibility of geologic isolation of nuclear wastes being carried out by the US Department of Energy and the National Cooperative for the Storage of Radioactive Waste of Switzerland

Low-frequency blood pressure oscillations and inotrope treatment failure in premature infants.

Science.gov (United States)

Vesoulis, Zachary A; Hao, Jessica; McPherson, Christopher; El Ters, Nathalie M; Mathur, Amit M

2017-07-01

The underlying mechanism as to why some hypotensive preterm infants do not respond to inotropic medications remains unclear. For these infants, we hypothesize that impaired vasomotor function is a significant factor and is manifested through a decrease in low-frequency blood pressure variability across regulatory components of vascular tone. Infants born ≤28 wk estimated gestational age underwent prospective recording of mean arterial blood pressure for 72 h after birth. After error correction, root-mean-square spectral power was calculated for each valid 10-min data frame across each of four frequency bands ( B1 , 0.005-0.0095 Hz; B2 , 0.0095-0.02 Hz; B3 , 0.02-0.06 Hz; and B4 , 0.06-0.16) corresponding to different components of vasomotion control. Forty infants (twenty-nine normotensive control and eleven inotrope-exposed) were included with a mean ± SD estimated gestational age of 25.2 ± 1.6 wk and birth weight 790 ± 211 g. 9.7/11.8 Million (82%) data points were error-free and used for analysis. Spectral power across all frequency bands increased with time, although the magnitude was 20% less in the inotrope-exposed infants. A statistically significant increase in spectral power in response to inotrope initiation was noted across all frequency bands. Infants with robust blood pressure response to inotropes had a greater increase compared with those who had limited or no blood pressure response. In this study, hypotensive infants who require inotropes have decreased low-frequency variability at baseline compared with normotensive infants, which increases after inotrope initiation. Low-frequency spectral power does not change for those with inotrope treatment failure, suggesting dysfunctional regulation of vascular tone as a potential mechanism of treatment failure. NEW & NOTEWORTHY In this study, we examine patterns of low-frequency oscillations in blood pressure variability across regulatory components of vascular tone in normotensive and

Efficient Outage Probability Evaluation of Diversity Receivers Over Generalized Gamma Channels

KAUST Repository

Ben Issaid, Chaouki

2016-10-01

In this paper, we are interested in determining the cumulative distribution function of the sum of generalized Gamma in the setting of rare event simulations. To this end, we present an efficient importance sampling estimator. The main result of this work is the bounded relative property of the proposed estimator. This result is used to accurately estimate the outage probability of multibranch maximum ratio combining and equal gain combining diversity receivers over generalized Gamma fading channels. Selected numerical simulations are discussed to show the robustness of our estimator compared to naive Monte Carlo.

Efficient Outage Probability Evaluation of Diversity Receivers Over Generalized Gamma Channels

KAUST Repository

Ben Issaid, Chaouki; Alouini, Mohamed-Slim; Tempone, Raul

2016-01-01

In this paper, we are interested in determining the cumulative distribution function of the sum of generalized Gamma in the setting of rare event simulations. To this end, we present an efficient importance sampling estimator. The main result of this work is the bounded relative property of the proposed estimator. This result is used to accurately estimate the outage probability of multibranch maximum ratio combining and equal gain combining diversity receivers over generalized Gamma fading channels. Selected numerical simulations are discussed to show the robustness of our estimator compared to naive Monte Carlo.

Failure to thrive in babies and toddlers.

Science.gov (United States)

Goh, Lay Hoon; How, Choon How; Ng, Kar Hui

2016-06-01

Failure to thrive in a child is defined as 'lack of expected normal physical growth' or 'failure to gain weight'. Diagnosis requires repeated growth measurements over time using local, age-appropriate growth centile charts. Premature babies with appropriate growth velocity and children with 'catch-down' growth, constitutional growth delay or familial short stature show normal growth variants, and usually do not require further evaluation. In Singapore, the most common cause of failure to thrive in children is malnutrition secondary to psychosocial and caregiver factors. 'Picky eating' is common in the local setting and best managed with an authoritative feeding style from caregivers. Other causes are malabsorption and existing congenital or chronic medical conditions. Child neglect or abuse should always be ruled out. Iron deficiency is the most common complication. The family doctor plays a pivotal role in early detection, timely treatment, appropriate referrals and close monitoring of 'catch-up' growth in these children. Copyright: © Singapore Medical Association.

Risk Factors for premature birth in a hospital

Directory of Open Access Journals (Sweden)

Margarita E. Ahumada-Barrios

Full Text Available Abstract Objective: to determine the risk factors for premature birth. Methods: retrospective case-control study of 600 pregnant women assisted in a hospital, with 298 pregnant women in the case group (who gave birth prematurely <37 weeks and 302 pregnant women who gave birth to a full-term newborn in the control group. Stata software version 12.2 was used. The Chi-square test was used in bivariate analysis and logistic regression was used in multivariate analysis, from which Odds Ratios (OR and Confidence Intervals (CI of 95% were derived. Results: risk factors associated with premature birth were current twin pregnancy (adjusted OR= 2.4; p= 0.02, inadequate prenatal care (< 6 controls (adjusted OR= 3.2; p <0.001, absent prenatal care (adjusted OR= 3.0; p <0.001, history of premature birth (adjusted OR= 3.7; p <0.001 and preeclampsia (adjusted OR= 1.9; p= 0.005. Conclusion: history of premature birth, preeclampsia, not receiving prenatal care and receiving inadequate prenatal care were risk factors for premature birth.

Frequency of neonatal complications after premature delivery

Directory of Open Access Journals (Sweden)

Gordana Grgić

2013-04-01

Full Text Available Introduction: Preterm delivery is the delivery before 37 weeks of gestation are completed. The incidence of preterm birth ranges from 5 to 15%. Aims of the study were to determine the average body weight, Apgar score after one and five minutes, and the frequency of the most common complications in preterminfants.Methods: The study involved a total of 631 newborns, of whom 331 were born prematurely Aims of this study were to (24th-37th gestational weeks-experimental group, while 300 infants were born in time (37-42 weeks of gestation-control group.Results: Average body weight of prematurely born infants was 2382 grams, while the average Apgar score in this group after the fi rst minute was 7.32 and 7.79 after the fifth minute. The incidence of respiratory distress syndrome was 50%, intracranial hemorrhage, 28.1% and 4.8% of sepsis. Respiratory distresssyndrome was more common in infants born before 32 weeks of gestation. Mortality of premature infants is present in 9.1% and is higher than that of infants born at term.Conclusions: Birth body weight and Apgar scores was lower in preterm infants. Respiratory distress syndrome is the most common fetal complication of prematurity. Intracranial hemorrhage is the second most common complication of prematurity. Mortality of premature infants is higher than the mortality of infants born at term birth.

The extent of intestinal failure-associated liver disease in patients referred for intestinal rehabilitation is associated with increased mortality: an analysis of the pediatric intestinal failure consortium database.

Science.gov (United States)

Javid, Patrick J; Oron, Assaf P; Duggan, Christopher; Squires, Robert H; Horslen, Simon P

2017-09-05

The advent of regional multidisciplinary intestinal rehabilitation programs has been associated with improved survival in pediatric intestinal failure. Yet, the optimal timing of referral for intestinal rehabilitation remains unknown. We hypothesized that the degree of intestinal failure-associated liver disease (IFALD) at initiation of intestinal rehabilitation would be associated with overall outcome. The multicenter, retrospective Pediatric Intestinal Failure Consortium (PIFCon) database was used to identify all subjects with baseline bilirubin data. Conjugated bilirubin (CBili) was used as a marker for IFALD, and we stratified baseline bilirubin values as CBili4 mg/dL. The association between baseline CBili and mortality was examined using Cox proportional hazards regression. Of 272 subjects in the database, 191 (70%) children had baseline bilirubin data collected. 38% and 28% of patients had CBili >4 mg/dL and CBili 4 mg/dL, prematurity, race, and small bowel atresia. On regression analysis controlling for age, prematurity, and diagnosis, the risk of mortality was increased by 3-fold for baseline CBili 2-4 mg/dL (HR 3.25 [1.07-9.92], p=0.04) and 4-fold for baseline CBili >4 mg/dL (HR 4.24 [1.51-11.92], p=0.006). On secondary analysis, CBili >4 mg/dL at baseline was associated with a lower chance of attaining enteral autonomy. In children with intestinal failure treated at intestinal rehabilitation programs, more advanced IFALD at referral is associated with increased mortality and decreased prospect of attaining enteral autonomy. Early referral of children with intestinal failure to intestinal rehabilitation programs should be strongly encouraged. Treatment Study, Level III. Copyright © 2017 Elsevier Inc. All rights reserved.

Path analysis of risk factors leading to premature birth.

Science.gov (United States)

Fields, S J; Livshits, G; Sirotta, L; Merlob, P

1996-01-01

The present study tested whether various sociodemographic, anthropometric, behavioral, and medical/physiological factors act in a direct or indirect manner on the risk of prematurity using path analysis on a sample of Israeli births. The path model shows that medical complications, primarily toxemia, chorioammionitis, and a previous low birth weight delivery directly and significantly act on the risk of prematurity as do low maternal pregnancy weight gain and ethnicity. Other medical complications, including chronic hypertension, preclampsia, and placental abruption, although significantly correlated with prematurity, act indirectly on prematurity through toxemia. The model further shows that the commonly accepted sociodemographic, anthropometric, and behavioral risk factors act by modifying the development of medical complications that lead to prematurity as opposed to having a direct effect on premature delivery. © 1996 Wiley-Liss, Inc. Copyright © 1996 Wiley-Liss, Inc.

An Internet of Things Approach to Electrical Power Monitoring and Outage Reporting

Energy Technology Data Exchange (ETDEWEB)

Koch, Daniel B [ORNL

2017-01-01

The so-called Internet of Things concept has captured much attention recently as ordinary devices are connected to the Internet for monitoring and control purposes. One enabling technology is the proliferation of low-cost, single board computers with built-in network interfaces. Some of these are capable of hosting full-fledged operating systems that provide rich programming environments. Taken together, these features enable inexpensive solutions for even traditional tasks such as the one presented here for electrical power monitoring and outage reporting.

Outcomes for Extremely Premature Infants

Science.gov (United States)

Glass, Hannah C.; Costarino, Andrew T.; Stayer, Stephen A.; Brett, Claire; Cladis, Franklyn; Davis, Peter J.

2015-01-01

Premature birth is a significant cause of infant and child morbidity and mortality. In the United States, the premature birth rate, which had steadily increased during the 1990s and early 2000s, has decreased annually for four years and is now approximately 11.5%. Human viability, defined as gestational age at which the chance of survival is 50%, is currently approximately 23–24 weeks in developed countries. Infant girls, on average, have better outcomes than infant boys. A relatively uncomplicated course in the intensive care nursery for an extremely premature infant results in a discharge date close to the prenatal EDC. Despite technological advances and efforts of child health experts during the last generation, the extremely premature infant (less than 28 weeks gestation) and extremely low birth weight infant (ELBW) (CPAP, mechanical ventilation, and exogenous surfactant increased survival and spurred the development of neonatal intensive care in the 1970s through the early 1990s. Routine administration of antenatal steroids during premature labor improved neonatal mortality and morbidity in the late 1990s. The recognition that chronic postnatal administration of steroids to infants should be avoided may have improved outcomes in the early 2000s. Evidence from recent trials attempting to define the appropriate target for oxygen saturation in preterm infants suggests arterial oxygen saturation between 91–95% (compared to 85–89%) avoids excess mortality. However, final analyses of data from these trials have not been published, so definitive recommendations are still pending The development of neonatal neurocognitive care visits may improve neurocognitive outcomes in this high-risk group. Long-term follow up to detect and address developmental, learning, behavioral, and social problems is critical for children born at these early gestational ages. The striking similarities in response to extreme prematurity in the lung and brain imply that agents and

Optimal utilization of outages. The tasks of the OEM and/or service provider

International Nuclear Information System (INIS)

Jakobs, Norbert; Grauf, Eberhard

1998-01-01

The deregulation of Europe's power market on January 1, 1999 will force many electric utilities and especially nuclear power plant operators to introduce extensive cost-cutting measures in order that they can hold their own in the new competitive environment. Existing plants basically have three potential ways of reducing their power generating costs: by increasing availability, reducing fuel costs and cutting back operating costs. Optimizing plant outages provides considerable potential for raising plant availability but can also lower operating costs by reducing expenditure on maintenance. In order to optimize an outage in terms of performance time and cost, there are a number of starting points based on certain key factors: organization, planning, logistics, performance monitoring, plant and equipment enhancements as well as personnel motivation. To reach this goal it is necessary for the original equipment manufacturer (OEM) and/or service provider to be involved in these activities to a much greater extent than before and for a closer form of partnership to be established with the consumer. For it is only within a team having a common set of goals that the successes of the past have been able to be achieved and new tasks can be efficiently handled in the future. (author)

Increased mortality after dronedarone therapy for severe heart failure

DEFF Research Database (Denmark)

Køber, Lars; Torp-Pedersen, Christian; McMurray, John J V

2008-01-01

BACKGROUND: Dronedarone is a novel antiarrhythmic drug with electrophysiological properties that are similar to those of amiodarone, but it does not contain iodine and thus does not cause iodine-related adverse reactions. Therefore, it may be of value in the treatment of patients with heart failure....... METHODS: In a multicenter study with a double-blind design, we planned to randomly assign 1000 patients who were hospitalized with symptomatic heart failure and severe left ventricular systolic dysfunction to receive 400 mg of dronedarone twice a day or placebo. The primary end point was the composite...... of death from any cause or hospitalization for heart failure. RESULTS: After inclusion of 627 patients (310 in the dronedarone group and 317 in the placebo group), the trial was prematurely terminated for safety reasons, at the recommendation of the data and safety monitoring board, in accordance...

Key issues for the control of refueling outage duration and costs in PWR nuclear power plants

International Nuclear Information System (INIS)

Degrave, C.; Martin-Onraet, M.

2000-01-01

For several years, EDF, within the framework of the CIDEM project and in collaboration with some German Utilities, has undertaken a detailed review of the operating experience both of its own NPP and of foreign units, in order to improve the performances of future units under design, particularly the French-German European Pressurized Reactor (EPR) project. This review made it possible to identify the key issues allowing to decrease the duration of refueling and maintenance outages. These key issues can be classified in 3 categories: Design; Maintenance and Logistic Support; Outage Management. Most key issues in the design field and some in the logistic support field have been studied and could be integrated into the design of any future PWR unit, as for the EPR project. Some of them could also be adapted to current plants, provided they are feasible and profitable. The organization must be tailored to each country, utility or period: it widely depends on the power production environment, particularly in a deregulation context. (author)

LIDAR AND INS FUSION IN PERIODS OF GPS OUTAGES FOR MOBILE LASER SCANNING MAPPING SYSTEMS

Directory of Open Access Journals (Sweden)

I. Klein

2012-09-01

Full Text Available Mobile laser scanning systems are becoming an increasingly popular means to obtain 3D coverage on a large scale. To perform the mapping, the exact position of the vehicle must be known throughout the trajectory. Exact position is achieved via integration of Global Positioning Systems (GPS and Inertial Navigation Systems (INS. Yet, in urban environments, cases of complete or even partial GPS outages may occur leaving the navigation solution to rely only on the INS. The INS navigation solution degrades with time as the Inertial Measurement Unit (IMU measurements contains noise, which permeates into the navigation equations. Degradation of the position determination leads to loss of data in such segments. To circumvent such drift and its effects, we propose fusing INS with lidar data by using building edges. This detection of edges is then translated into position data, which is used as an aiding to the INS. It thereby enables the determination of the vehicle position with a satisfactory level accuracy, sufficient to perform the laser-scanning based mapping in those outage periods.

Maternal assessment of pain in premature infants

Directory of Open Access Journals (Sweden)

Maria Carolina Correia dos Santos

2015-12-01

Full Text Available Objective: to identify mothers' perceptions about the pain in their premature babies in the Neonatal Intensive Care Unit. Methods: evaluative, quantitative study with investigative nature conducted with 19 mothers of hospitalized premature newborns. Data were obtained from closed questions, answered by mothers. Results: from the participants, two (10.5% reported that newborns are unable to feel pain. From the 17 mothers who said that premature babies can feel pain, the majority (94.1% identified crying as a characteristic of pain sensation. Eleven (64.7% stated that uneasiness is a sign of pain in newborns. Conclusion: for the proper management of neonatal pain it is essential that mothers know the signs of pain in premature newborns, and that health professionals instruct this recognition, through the enhancement of the maternal presence and practice of effective communication between professionals and newborns’ families.

RESEARCHES RELATED TO THE REDUCTION OF PREMATURITY THROUGH PREMATURE RUPTURE OF MEMBRANES IN 2017

Directory of Open Access Journals (Sweden)

Maria BOLOTA

2017-06-01

Full Text Available Data from literature, especially from the US, has provided data on prediction, prevention and treatment of premature membrane rupture (RPM. RPM is a significant cause of premature birth and can cause complications of a term task. Considerable research on RPM has led to a better understanding of the mechanism of spontaneous breakage of membranes, risk factors, and good results for newborns resulting from such obstetrical events. Spontaneous rupture of the membranes increases the risk of intrauterine infection and umbilical cord compression as well as the risk of premature detachment of placenta. Newborn babies resulting from RPM have an increased risk of morbidity compared to gestational age, and the risk of infection is increased compared with other premature babies due to ancillary causes. If RPM occurs in the second trimester, there is an additional risk of pulmonary hypoplasia and hip dysplasia. Pre-term conservative treatment prolongs latency to birth. Antibiotics reduce the risk of infection while corticosteroid treatment (dexamethasone reduces respiratory complications and interventricular haemorrhage without increasing the risk of infection. Birth is necessary or unavoidable in many cases by RPMs and because conservative treatment often results in no results; That is why studies are needed to identify all risk factors and the need to treat pregnant women at risk of RPM; 17-hydroxy-progesterone is a specific treatment for preventing recurrent membrane rupture. (http://www.ginecologultau.ro/ruptura-prematura-a-membranelor, 2013.

Symbolic transfer entropy-based premature signal analysis

International Nuclear Information System (INIS)

Wang Jun; Yu Zheng-Feng

2012-01-01

In this paper, we use symbolic transfer entropy to study the coupling strength between premature signals. Numerical experiments show that three types of signal couplings are in the same direction. Among them, normal signal coupling is the strongest, followed by that of premature ventricular contractions, and that of atrial premature beats is the weakest. The T test shows that the entropies of the three signals are distinct. Symbolic transfer entropy requires less data, can distinguish the three types of signals and has very good computational efficiency. (interdisciplinary physics and related areas of science and technology)

Social support for parents of premature infants

Directory of Open Access Journals (Sweden)

Agnieszka Skurzak

2018-03-01

Full Text Available Prematurity is still an actual medical problem. Significant increase in the survival rate of premature babies is observed due to the progress in perinatal care .Usually, parents are not prepared for a premature birth, for the majority of them the hospitalization of a child in neonatal intensive care unit is a source of fear,  moreover parents often blame themselves for the situation. Appearing emotions and questions require a compatible response from the therapeutic team. The most important activity in the practice of the team is emotional, informative, evaluative support.

Early menarche, nulliparity and the risk for premature and early natural menopause.

Science.gov (United States)

Mishra, Gita D; Pandeya, Nirmala; Dobson, Annette J; Chung, Hsin-Fang; Anderson, Debra; Kuh, Diana; Sandin, Sven; Giles, Graham G; Bruinsma, Fiona; Hayashi, Kunihiko; Lee, Jung Su; Mizunuma, Hideki; Cade, Janet E; Burley, Victoria; Greenwood, Darren C; Goodman, Alissa; Simonsen, Mette Kildevæld; Adami, Hans-Olov; Demakakos, Panayotes; Weiderpass, Elisabete

2017-03-01

Are parity and the timing of menarche associated with premature and early natural menopause? Early menarche (≤11 years) is a risk factor for both premature menopause (final menstrual period, FMP menopause (FMP 40-44 years), a risk that is amplified for nulliparous women. Women with either premature or early menopause face an increased risk of chronic conditions in later life and of early death. Findings from some studies suggest that early menarche and nulliparity are associated with early menopause, however overall the evidence is mixed. Much of the evidence for a direct relationship is hampered by a lack of comparability across studies, failure to adjust for confounding factors and inadequate statistical power. This pooled study comprises 51 450 postmenopausal women from nine observational studies in the UK, Scandinavia, Australia and Japan that contribute to the International collaboration for a Life course Approach to reproductive health and Chronic disease Events (InterLACE). Age at menarche (categorized as ≤11, 12, 13, 14 and 15 or more years) and parity (categorized as no children, one child and two or more children) were exposures of interest. Age at FMP was confirmed by at least 12 months of cessation of menses where this was not the result of an intervention (such as surgical menopause due to bilateral oophorectomy or hysterectomy) and categorized as premature menopause (FMP before age 40), early menopause (FMP 40-44 years), 45-49 years, 50-51 years, 52-53 years and 54 or more years. We used multivariate multinomial logistic regression models to estimate relative risk ratio (RRR) and 95% CI for associations between menarche, parity and age at FMP adjusting for within-study correlation. The median age at FMP was 50 years (interquartile range 48-53 years), with 2% of the women experiencing premature menopause and 7.6% early menopause. Women with early menarche (≤11 years, compared with 12-13 years) were at higher risk of premature menopause (RRR 1

Noninvasive Ventilation in Premature Neonates.

Science.gov (United States)

Flanagan, Keri Ann

2016-04-01

The use of noninvasive ventilation is a constantly evolving treatment option for respiratory disease in the premature infant. The goals of these noninvasive ventilation techniques are to improve gas exchange in the premature infant's lungs and to minimize the need for intubation and invasive mechanical ventilation. The goals of this article are to consider various uses of nasal interfaces, discuss skin care and developmental positioning concerns faced by the bedside nurse, and discuss the medical management aimed to reduce morbidity and mortality. This article explores the nursing role, the advances in medical strategies for noninvasive ventilation, and the team approach to noninvasive ventilation use in this population. Search strategy included a literature review on medical databases, such as EBSCOhost, CINAHL, PubMed, and NeoReviews. Innovative products, nursing research on developmental positioning and skin care, and advanced medical management have led to better and safer outcomes for premature infants requiring noninvasive ventilation. The medical focus of avoiding long-term mechanical ventilation would not be possible without the technology to provide noninvasive ventilation to these premature infants and the watchful eye of the nurse in terms of careful positioning, preventing skin breakdown and facial scarring, and a proper seal to maximize ventilation accuracy. This article encourages nursing-based research to quantify some of the knowledge about skin care and positioning as well as research into most appropriate uses for noninvasive ventilation devices.

Assessment of productivity at four generating plants

International Nuclear Information System (INIS)

Saarlas, M.; Nelson, M.

1976-01-01

The 1975 FEA study of power plant reliability was undertaken as a first step in improving the productivity of large (larger than 400 MW) generating units by attempting to trace outages to their root causes so that meaningful corrective action can be taken at the root of the problem. Trident Engineering Associates studied the operation, maintenance, management, and manning of two fossil-fueled and two nuclear-fueled units, one each of above average and one below average reliability (high availability and low forced outage rate). It was expected that the differences between a highly reliable unit and a less reliable unit would lead to recommendations which would be useful for improving productivity of units throughout the country. The findings are of two basic types: (1) general concepts covering problem areas, fundamental reasons and immediate symptoms behind the problems, methods used to eliminate or alleviate the problems, and proposed solutions; (2) details which provide statistics that establish the relative lost productivity by fundamental causes. Eight root causes (fundamental reasons for failures or outages) were established into which most failures and outages could be assigned. Twenty nine cause factors (causes of failure) were established which assisted in assigning the failures and outages to a root cause

Grid-connected photovoltaic (PV) systems with batteries storage as solution to electrical grid outages in Burkina Faso

International Nuclear Information System (INIS)

Abdoulaye, D; Koalaga, Z; Zougmore, F

2012-01-01

This paper deals with a key solution for power outages problem experienced by many African countries and this through grid-connected photovoltaic (PV) systems with batteries storage. African grids are characterized by an insufficient power supply and frequent interruptions. Due to this fact, users who especially use classical grid-connected photovoltaic systems are unable to profit from their installation even if there is sun. In this study, we suggest the using of a grid-connected photovoltaic system with batteries storage as a solution to these problems. This photovoltaic system works by injecting the surplus of electricity production into grid and can also deliver electricity as a stand-alone system with all security needed. To achieve our study objectives, firstly we conducted a survey of a real situation of one African electrical grid, the case of Burkina Faso (SONABEL: National Electricity Company of Burkina). Secondly, as study case, we undertake a sizing, a modeling and a simulation of a grid-connected PV system with batteries storage for the LAME laboratory at the University of Ouagadougou. The simulation shows that the proposed grid-connected system allows users to profit from their photovoltaic installation at any time even if the public electrical grid has some failures either during the day or at night.

Falência ovariana precoce associada a deleção no braço longo do cromossomo: relato de dois casos e revisão da literatura Premature ovarian failure with a deletion in the long arm of chromosome: report of two cases and review of the literature

Directory of Open Access Journals (Sweden)

Mariangela Badalotti

2006-09-01

Full Text Available Falência ovariana prematura pode ser idiopática ou estar associada a várias distúrbios auto-imunes ou genéticos, como as deleções do cromossomo X. Relatamos dois novos casos de deleções do braço longo do cromossomo X, em pacientes nuligrávidas apresentando amenorréia secundária e infertilidade. Nenhuma paciente referia história familiar de falência ovariana prematura e relatavam desenvolvimento puberal normal. A avaliação genética mostrou deleção distal no braço longo do cromossomo X, sendo os resultados 46,X,del(Xq22 e 46,X,del(Xq13q28, respectivamente. Após o diagnóstico as pacientes optaram por fertilização in vitro com óvulos doados.Premature ovarian failure may be idiopathic or associated with several autoimmune and genetic disorders as X chromosome deletions. We report two cases of preamture ovarian failure associated with a deletion in the long arm of X chromosome. Both patients were nulligravidas presenting secondary amenorrhea and complaints of infertility, without family history of premature ovarian failure and reporting normal puberal development. Their karyotypes showed deletions of the distal long arm of all X chromosomes and were 46,X, del(Xq22 and 46,X, del(Xq13q28, respectively. After the diagnosis the patients decided to be submitted to an in vitro fertilization with egg donation.

Methodology if inspections to carry out the nuclear outages model; Metodologia de inspeccciones para cumplir el modelo de paradas nucleares

Energy Technology Data Exchange (ETDEWEB)

Aycart, J.; Mortenson, S.; Fourquet, J. M.

2005-07-01

Before the nuclear generation industry was deregulated in the United States, refueling and maintenance outages in nuclear power plants usually lasted orotund 100 days. After deregulation took effect, improved capability factors and performances became more important. As a result, it became essential to reduce the critical path time during the outage, which meant that activities that had typically been done in series had to be executed in parallel. The new outage model required the development of new tools and new processes, The 360-degree platform developed by GE Energy has made it possible to execute multiple activities in parallel. Various in-vessel visual inspection (IVVI) equipments can now simultaneously perform inspections on the pressurized reactor vessel (RPV) components. The larger number of inspection equipments in turn results in a larger volume of data, with the risk of increasing the time needed for examining them and postponing the end of the analysis phase, which is critical for the outage. To decrease data analysis times, the IVVI Digitalisation process has been development. With this process, the IVVI data are sent via a high-speed transmission line to a site outside the Plant called Center of Excellence (COE), where a team of Level III experts is in charge of analyzing them. The tools for the different product lines are being developed to interfere with each other as little as possible, thus minimizing the impact of the critical path on plant refueling activities. Methods are also being developed to increase the intervals between inspection. In accordance with the guidelines of the Boiling Water Reactor Vessel and Internals project (BWRVIP), the intervals between inspections are typically longer if ultrasound volumetric inspections are performed than if the scope is limited to IVVI. (Author)

Exact closed form expressions for outage probability of GSC receivers over Rayleigh fading channel subject to self-interference

KAUST Repository

Nam, Sungsik; Hasna, Mazen Omar; Alouini, Mohamed-Slim

2010-01-01

in mind, we capitalize in this paper on some new order statistics results to derive exact closed-form expressions for outage probability of GSC RAKE receivers subject to self-interference over independent and identically distributed Rayleigh fading

Aggressive Posterior Retinopathy of Prematurity in a Premature Male Infant

Directory of Open Access Journals (Sweden)

Jun Zhou

2017-07-01

Full Text Available A premature male infant was born at 30 weeks’ gestation with a birth weight of 1,700 g in a rural hospital. He was diagnosed with respiratory distress syndrome and received continuous positive airway pressure treatment for 26 days. At 26 days after birth, the patient was transferred to our hospital for further evaluation and management. A comprehensive eye examination revealed a stage 3 retinopathy of prematurity (ROP involving zone 2 in both eyes. The patient was recommended to a provincial-level eye hospital for emergency laser therapy. Five months after birth, the feedback from the eye hospital showed that the patient had a high risk of blindness in both eyes. Our case report shows that delaying first screening examination increases the possibility of developing aggressive posterior ROP in infants with ROP. Doctors in rural hospitals should be aware of this possibility and trained for early screening and treatment in high-risk infants.

Optimal oxygen saturation in premature infants

Directory of Open Access Journals (Sweden)

Meayoung Chang

2011-09-01

Full Text Available There is a delicate balance between too little and too much supplemental oxygen exposure in premature infants. Since underuse and overuse of supplemental oxygen can harm premature infants, oxygen saturation levels must be monitored and kept at less than 95% to prevent reactive oxygen species-related diseases, such as retinopathy of prematurity and bronchopulmonary dysplasia. At the same time, desaturation below 80 to 85% must be avoided to prevent adverse consequences, such as cerebral palsy. It is still unclear what range of oxygen saturation is appropriate for premature infants; however, until the results of further studies are available, a reasonable target for pulse oxygen saturation (SpO2 is 90 to 93% with an intermittent review of the correlation between SpO2 and the partial pressure of arterial oxygen tension (PaO2. Because optimal oxygenation depends on individuals at the bedside making ongoing adjustments, each unit must define an optimal target range and set alarm limits according to their own equipment or conditions. All staff must be aware of these values and adjust the concentration of supplemental oxygen frequently.

47 CFR 4.11 - Notification and initial and final communications outage reports that must be filed by...

Science.gov (United States)

2010-10-01

... Notification shall provide: The name of the reporting entity; the date and time of onset of the outage; a brief... FEDERAL COMMUNICATIONS COMMISSION GENERAL DISRUPTIONS TO COMMUNICATIONS Reporting Requirements for... and contact telephone number by which the Commission's technical staff may contact the reporting...

Operational readiness verification, phase 1: A study on safety during outage and restart of nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Hollnagel, E. [Linkoeping Univ. (Sweden). Dept. of Computer and Information Science; Gauthereau, V. [Linkoeping Univ. (Sweden). Dept. of Industrial Engineering

2001-06-01

This report contains the findings from the first phase of a study on safety during outage and restart of nuclear power plants. Operational Readiness Verification (ORV) - in Swedish called Driftklarhetsverifiering (DKV) - refers to the test and verification activities that are necessary to ensure that plant systems are able to provide their required functions when needed - more concretely that all plant systems are in their correct functional state when the plant is restarted after an outage period. The concrete background for this work is that nine ORV related incidents were reported in Sweden between July 1995 and October 1998. The work reported here comprised a literature survey of research relevant for ORV issues, and an assessment of the present situation at Swedish NPPs with respect to ORV. The literature survey was primarily aimed at research related to NPPs, but also looked at domains where similar problems have occurred, such as maintenance in commercial aviation. The survey looked specifically for organisational and MTO aspects relevant to the present situation in Swedish NPPs. One finding was that ORV should be seen as an integral part of maintenance, rather than as a separate activity. Another, that there is a characteristic distribution of error modes for maintenance and ORV, with many sequence errors and omissions, rather than a set of unique error modes. An international study further showed that there are important differences in how procedures are used, and in the balance between decentralisation and centralisation. Several studies also suggested that ORV could usefully be described as a barrier system in relation to the flow of work, for instance using the following five stages: (1) preventive actions during maintenance/outage, (2) post-test after completion of work, (3) pre-test before start-up, (4) the start-up sequence itself, and (5) preventive actions during power operation - possibly including automatic safety systems. In the field survey

Operational readiness verification, phase 1: A study on safety during outage and restart of nuclear power plants

International Nuclear Information System (INIS)

Hollnagel, E.; Gauthereau, V.

2001-06-01

This report contains the findings from the first phase of a study on safety during outage and restart of nuclear power plants. Operational Readiness Verification (ORV) - in Swedish called Driftklarhetsverifiering (DKV) - refers to the test and verification activities that are necessary to ensure that plant systems are able to provide their required functions when needed - more concretely that all plant systems are in their correct functional state when the plant is restarted after an outage period. The concrete background for this work is that nine ORV related incidents were reported in Sweden between July 1995 and October 1998. The work reported here comprised a literature survey of research relevant for ORV issues, and an assessment of the present situation at Swedish NPPs with respect to ORV. The literature survey was primarily aimed at research related to NPPs, but also looked at domains where similar problems have occurred, such as maintenance in commercial aviation. The survey looked specifically for organisational and MTO aspects relevant to the present situation in Swedish NPPs. One finding was that ORV should be seen as an integral part of maintenance, rather than as a separate activity. Another, that there is a characteristic distribution of error modes for maintenance and ORV, with many sequence errors and omissions, rather than a set of unique error modes. An international study further showed that there are important differences in how procedures are used, and in the balance between decentralisation and centralisation. Several studies also suggested that ORV could usefully be described as a barrier system in relation to the flow of work, for instance using the following five stages: (1) preventive actions during maintenance/outage, (2) post-test after completion of work, (3) pre-test before start-up, (4) the start-up sequence itself, and (5) preventive actions during power operation - possibly including automatic safety systems. In the field survey

Operational readiness verification, phase 1: A study on safety during outage and restart of nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Hollnagel, E [Linkoeping Univ. (Sweden). Dept. of Computer and Information Science; Gauthereau, V [Linkoeping Univ. (Sweden). Dept. of Industrial Engineering

2001-06-01

This report contains the findings from the first phase of a study on safety during outage and restart of nuclear power plants. Operational Readiness Verification (ORV) - in Swedish called Driftklarhetsverifiering (DKV) - refers to the test and verification activities that are necessary to ensure that plant systems are able to provide their required functions when needed - more concretely that all plant systems are in their correct functional state when the plant is restarted after an outage period. The concrete background for this work is that nine ORV related incidents were reported in Sweden between July 1995 and October 1998. The work reported here comprised a literature survey of research relevant for ORV issues, and an assessment of the present situation at Swedish NPPs with respect to ORV. The literature survey was primarily aimed at research related to NPPs, but also looked at domains where similar problems have occurred, such as maintenance in commercial aviation. The survey looked specifically for organisational and MTO aspects relevant to the present situation in Swedish NPPs. One finding was that ORV should be seen as an integral part of maintenance, rather than as a separate activity. Another, that there is a characteristic distribution of error modes for maintenance and ORV, with many sequence errors and omissions, rather than a set of unique error modes. An international study further showed that there are important differences in how procedures are used, and in the balance between decentralisation and centralisation. Several studies also suggested that ORV could usefully be described as a barrier system in relation to the flow of work, for instance using the following five stages: (1) preventive actions during maintenance/outage, (2) post-test after completion of work, (3) pre-test before start-up, (4) the start-up sequence itself, and (5) preventive actions during power operation - possibly including automatic safety systems. In the field survey

Accurate outage analysis of incremental decode-and-forward opportunistic relaying

KAUST Repository

Tourki, Kamel; Yang, Hongchuan; Alouini, Mohamed-Slim

2011-01-01

In this paper, we investigate a dual-hop decode-and-forward opportunistic relaying scheme where the selected relay chooses to cooperate only if the source-destination channel is of an unacceptable quality. We first derive the exact statistics of received signal-to-noise (SNR) over each hop with co-located relays, in terms of probability density function (PDF). Then, the PDFs are used to determine very accurate closed-form expression for the outage probability for a transmission rate R. Furthermore, we perform asymptotic analysis and we deduce the diversity order of the scheme. We validate our analysis by showing that performance simulation results coincide with our analytical results over different network architectures. © 2011 IEEE.

Accurate outage analysis of incremental decode-and-forward opportunistic relaying

KAUST Repository

Tourki, Kamel

2011-04-01

In this paper, we investigate a dual-hop decode-and-forward opportunistic relaying scheme where the selected relay chooses to cooperate only if the source-destination channel is of an unacceptable quality. We first derive the exact statistics of received signal-to-noise (SNR) over each hop with co-located relays, in terms of probability density function (PDF). Then, the PDFs are used to determine very accurate closed-form expression for the outage probability for a transmission rate R. Furthermore, we perform asymptotic analysis and we deduce the diversity order of the scheme. We validate our analysis by showing that performance simulation results coincide with our analytical results over different network architectures. © 2011 IEEE.

Insights from the analyses of risk-informed extension of diesel generator allowed outage time

International Nuclear Information System (INIS)

Lin, J.C.; He Wei

2005-01-01

In recent years, many U.S. nuclear plants have applied and received approval for the risk-informed extension of the Allowed Outage Time (AOT) for Emergency Diesel Generators (EDGs). These risk-informed applications need to meet the regulatory guidance on the risk criteria. This paper discusses in detail insights derived from the risk-informed analyses performed to support these applications. The risk criteria on ΔCDF/ΔLERF evaluate the increase in average risk by extending the AOT for EDGs, induced primarily by an increase in EDG maintenance unavailability due to the introduction of additional EDG preventive maintenance. By performing this preventive maintenance work on-line, the outage duration can be shortened. With proper refinement of the risk model, most plants can meet the ΔCDF/ΔLERF criteria for extending the EDGAOT from, for example, 3 days to 14 days. The key areas for model enhancements to meet these criteria include offsite/onsite power recovery, LERF modeling, etc. The most important LERF model enhancements consist of refinement of the penetrations included in the containment isolation model for the consideration of a large release, and taking credit for operator vessel depressurization during the time period between core damage and vessel failure. A recent study showed that although the frequency of loss of offsite power (LOSP) has decreased, the duration of offsite power recovery has actually increased. However, many of the events used to derive this conclusion may not be applicable to PRAs. One approach develops the offsite power non-recovery factor by first screening the LOSP events for applicability to the plant being analyzed, power operation, and LOSP initiating event, then using the remaining events data for the derivation based on the fraction of events with recovery duration longer than the time window allowed. The risk criteria on ICCDP/ICLERP examine the increase in risk from the average CDF/LERF, based on the increased maintenance

[Family participation in premature care in neonatal ICU].

Science.gov (United States)

Gaíva, Maria Aparecida Munhoz; Scochi, Carmen Gracinda Silvan

2005-01-01

This study aimed at analyzing the family participation in the premature assistance in a university hospital neonatal ICU. Data were collected from the participant observation. Results showed that despite of the mother's presence in the daily life of their premature children placed in a hospital, family isn't inserted in the work process and mothers are the only ones who take part of the cares. This participation basically happens in the execution of maternity care, especially at the medium risk unity, the mother and premature family are less welcomed and there isn't any partnership between the care team and the family, there aren't team interventions in order to turn premature family in autonomous subject to promote health and life quality to baby's life.

[Professor LAI Xinsheng's clinical experience in the treatment of premature ovarian failure with tongyuan acupuncture technique and Chinese herbal medicine].

Science.gov (United States)

Li, Xiaozhe; Zhang, Sujuan

2017-03-12

In the treatment of premature ovarian failure (POF), professor LAI Xinsheng focuses on the determination of syndrome to seek for etiology, associating with the differentiation of meridian and collateral and that of zangfu organs. Professor LAI believes that POF is mainly manifested as amenorrhea and infertility, localized in the kidney, with the dysfunction of liver, spleen and heart. It is impacted by many pathological factors, such as cold blockage, qi stagnation, blood stagnation, blood deficiency, yin deficiency, etc., which leads to the damage of the thoroughfare vessel and the conception vessel and the blockage of menstrual flow. On the basis of four diagnostic Methods and syndrome differentiation, there are four common syndromes of POF, named qi and blood deficiency, qi and blood stagnation, liver and kidney deficiency and yang deficiency of spleen and kidney. Tongyuan acupuncture technique is summarized by Professor LAI Xinsheng on the basis of yinyang theory. It is an effective and scientific method for acupoint selection along the meridians. The acupoints on the back, communicating with the governor vessel and mind regulation, acting on the brain are selected to promote yang qi of the governor vessel. The back- shu points of five zang organs are selected to regulate the functions of internal organs. The acupoints on the abdomen and the conception vessel are selected to conduce qi to the primary so as to improve reproductive function. In the guidance of tongyuan acupuncture technique, the acupoint prescription is formed and the Chinese herbal medicines are selected in combination to improve ovarian function and regulate menstruation. Hence, the satisfactory therapeutic effects have been achieved.

Effect of stem cell transplantation of premature ovarian failure in animal models and patients: A meta-analysis and case report.

Science.gov (United States)

Chen, Lei; Guo, Shilei; Wei, Cui; Li, Honglan; Wang, Haiya; Xu, Yan

2018-05-01

Stem cell transplantation has been considered a promising therapeutic approach for premature ovarian failure (POF). However, to date, no quantitative data analysis of stem cell therapy for POF has been performed. Therefore, the present study performed a meta-analysis to assess the efficacy of stem cell transplantation in improving ovarian function in animal models of POF. In addition, a case report of a patient with POF subjected to stem cell treatment was included to demonstrate that stem cell therapy also contributes to the recovery of ovarian function in patients. Published studies were identified by a systematic review of the PubMed, Embase, and Cochrane's library databases, and references cited in associated reviews were also considered. Data regarding follicle-stimulating hormone (FSH), estradiol (E2), ovarian weight, follicle count, the number of pregnancies and other parameters, including delivery route and cell type, were extracted. Pooled analysis, sensitivity analyses, subgroup analyses and meta-regression were performed. In the case of POF, transvaginal ultrasound (TVS), abdominal ultrasound (TAS) and color Doppler flow imaging (CDFI) were performed to observe the endometrial morphology and blood flow signals in the patient. Overall, pooled results from 16 pre-clinical studies demonstrated that stem cell-based therapy significantly improved FSH levels [standardized mean difference (SMD)=-1.330; 95% confidence interval (CI), -(2.095-0.565); P=0.001], E2 levels (SMD=2.334; 95% CI, 1.350-3.319; Pstem cell-based therapy may be an effective method for the resumption of ovarian function in a patient and in animal models of POF; however, large-scale and high-quality future studies are required to confirm the present findings due to heterogeneity.

Air traffic control : good progress on interim replacement for outage-plagued system, but risks can be further reduced

Science.gov (United States)

1996-10-01

Certain air traffic control(ATC) centers experienced a series of major outages, : some of which were caused by the Display Channel Complex or DCC-a mainframe : computer system that processes radar and other data into displayable images on : controlle...

Risk Factors for premature birth in a hospital 1

Science.gov (United States)

Ahumada-Barrios, Margarita E.; Alvarado, German F.

2016-01-01

Abstract Objective: to determine the risk factors for premature birth. Methods: retrospective case-control study of 600 pregnant women assisted in a hospital, with 298 pregnant women in the case group (who gave birth prematurely <37 weeks) and 302 pregnant women who gave birth to a full-term newborn in the control group. Stata software version 12.2 was used. The Chi-square test was used in bivariate analysis and logistic regression was used in multivariate analysis, from which Odds Ratios (OR) and Confidence Intervals (CI) of 95% were derived. Results: risk factors associated with premature birth were current twin pregnancy (adjusted OR= 2.4; p= 0.02), inadequate prenatal care (< 6 controls) (adjusted OR= 3.2; p <0.001), absent prenatal care (adjusted OR= 3.0; p <0.001), history of premature birth (adjusted OR= 3.7; p <0.001) and preeclampsia (adjusted OR= 1.9; p= 0.005). Conclusion: history of premature birth, preeclampsia, not receiving prenatal care and receiving inadequate prenatal care were risk factors for premature birth. PMID:27463110

Time trends and risk factor associated with premature birth and infants deaths due to prematurity in Hubei Province, China from 2001 to 2012.

Science.gov (United States)

Xu, Haiqing; Dai, Qiong; Xu, Yusong; Gong, Zhengtao; Dai, Guohong; Ding, Ming; Duggan, Christopher; Hu, Zubin; Hu, Frank B

2015-12-10

The nutrition and epidemiologic transition has been associated with an increasing incidence of preterm birth in developing countries, but data from large observational studies in China have been limited. Our study was to describe the trends and factors associated with the incidence of preterm birth and infant mortality due to prematurity in Hubei Province, China. We conducted a population-based survey through the Maternal and Child Health Care Network in Hubei Province from January 2001 to December 2012. We used data from 16 monitoring sites to examine the trend and risk factors for premature birth as well as infant mortality associated with prematurity. A total of 818,481 live births were documented, including 76,923 preterm infants (94 preterm infants per 1,000 live births) and 2,248 deaths due to prematurity (2.75 preterm deaths per 1,000 live births). From 2001 to 2012, the incidence of preterm birth increased from 56.7 to 105.2 per 1,000 live births (P for trend prematurity declined from 95.0 to 13.4 per 1,000 live births (P for trend prematurity were observed in Hubei Province from 2001 to 2012. Our results provide important information for areas of improvements in reducing incidence and mortality of premature birth.

Outage and ser performance of an opportunistic multi-user underlay cognitive network

KAUST Repository

Khan, Fahd Ahmed

2012-10-01

Consider a multi-user underlay cognitive network where multiple cognitive users concurrently share the spectrum with a primary network and a single secondary user is selected for transmission. The channel is assumed to have independent but not identical Nakagami-m fading. Closed form expressions for the outage performance and the symbol-error-rate performance of the opportunistic multi-user secondary network are derived when a peak interference power constraint is imposed on the secondary network in addition to the limited peak transmit power of each secondary user. © 2012 IEEE.

Human cytomegalovirus infections in premature infants by ...

African Journals Online (AJOL)

Freezing breast milk may be protective for the preterm infant until the titer of CMV antibody increases. However clinical importance of CMV infection in premature infants by breast-feeding is still unclear. This minireview focuses on recent advances in the study of CMV infection in premature infants by breastfeeding.

SAFETY ALERT - Failure of brass non-return valves in gas point installations

CERN Multimedia

HSE Unit

2016-01-01

There have been three recent failures in brass non-return valves in separate high pressure gas point installations across CERN. Whilst each was in a different gas service, the visual nature of the failure has been similar.   In all three cases, these components were connected to stainless steel flexible connections and stainless steel pipework. From the metallurgical investigation of the failed component, it appears that the failure is linked to uncontrolled tightening, leading to a localised weakening resulting in premature failure when subjected to pressure. Lead levels in the examined components appear to be a contributing factor to the reduction in ductility but are not identified as the root cause. It has also not been possible to attribute failure to a particular batch of material. The Occupational Health & Safety and Environmental Protection Unit prescribes the following actions to be taken, aligned with the CERN Safety Rules: Verification of all brass non-return valves (prioritising...

Premature ejaculation: A clinical review for the general physician.

Science.gov (United States)

Chung, Eric; Gilbert, Brent; Perera, Marlon; Roberts, Matthew J

2015-10-01

Premature ejaculation is one of the most common sexual dysfunctions in men. Recent epidemiological studies suggest its prevalence in Australia may range from 21-31% This article will discuss the current definition of premature ejaculation from a urological perspective. It will provide an understanding of the pathogenesis of premature ejaculation, as well as assessment and management options. Premature ejaculation can have a significant adverse effect on the quality of life for the patient and his sexual partners. It can potentially lead to psychological distress, diminished self- esteem, anxiety, erectile dysfunction, reduced libido and poor interpersonal relationships. Most men feel reluctant to discuss premature ejaculation with their general practitioner despite its psychological, emotional and relational effects. Effective, evidence-based treatment options are available and physicians should feel confident when exploring ways to improve the quality of life for men with sexual dysfunction.

Retinopathy of prematurity: an epidemic in the making.

Science.gov (United States)

Quinn, Graham E; Gilbert, Clare; Darlow, Brian A; Zin, Andrea

2010-10-01

To explore the etiology, incidence and methods to prevent and treat severe retinopathy of prematurity (ROP), which is rapidly becoming a threat to the vision of babies in areas of the world where increasing numbers of premature babies are surviving. The data used in this review were mainly from Medline and PubMed published in English. The search term was "retinopathy of prematurity and premature birth". We discuss the historical perspectives, prevalence and incidence, classification and treatment methods of ROP in premature babies. Peripheral retinal ablation for eyes with severe ROP can help prevent progression to blindness and several large clinical trials have shown the effectiveness of this treatment in high risk eyes. As a greater proportion of VLBW and ELBW babies survive, the population of babies at risk increases. In various regions of the world, different identification criteria are used to determine which babies are at risk of blindness in order to provide timely diagnostic examinations and treatment as needed. Methods for preventing ROP include better ante-natal and obstetric care leading to a reduction in the rate of prematurity, the use of ante-natal corticosteroids, and better neonatal care practices. Recent developments have indicated that management of oxygen supplementation is important for the prevention of severe ROP; however, there is not yet known what oxygen saturation target should be adopted. Sepsis increases severe ROP in very preterm infants. Genetic associations and a telemedicine approach may be explored to detect ROP. Treatment of anti-VEGF therapy are potentially useful in eyes with severe ROP, but long term effects are not yet known and such treatment should be used with great caution. ROP is a potentially binding disease for premature babies which is becoming more prevalent with the development improving neonatal services in many countries in recent years. High priority should be placed on developing approaches to prevent ROP

Integrated services as the key to the optimisation of refueling outages

International Nuclear Information System (INIS)

Ortega, Juan; Gonzalez, Roberto; Gutierrez, Jose E.

2010-01-01

Refueling outages at nuclear power plants are subject to demanding improvement criteria in each and every one of the activities scheduled. The management of activities on the refueling floor, including the phases of opening and closing of the reactor vessel and associated tasks relating to the reactor internals, the unloading, loading and management of the irradiated fuel and activities requested for the in-service inspection of essential primary circuit components, are interventions that have an impact on the refueling critical path and whose overall integration allows for significant optimization of the entire management of this fundamental refueling activity. For several years now, ENUSA, as the company specializing in irradiated fuel services, TECNATOM as the company responsible for the in-service inspection of critical primary side components and Westinghouse as the technology provider and specialist in the supply of plant support services, have together formed a solid working team offering this integrated refueling service to the Spanish plants. Today, the new and heightened demands regarding the training and specialization of the personnel participating in refueling outages, the need to consider contingencies in the activities scheduled and the objectives relating to the ALARA concept and safe operations require that this service include new activities providing synergies and leading to higher levels of commitment to excellence. This paper will present the service model developed, the most significant activities integrated in the service and the advantages and milestones achieved and reached during this period, compared to the conventional distributed functions model. Likewise, an analysis will be made of the new challenges that are being addressed, with a view to bringing about a more global integration. (authors)

Relationship between serum 25-hydroxy vitamin D levels and retinopathy of prematurity.

Science.gov (United States)

Kabataş, Emrah Utku; Dinlen, Nurdan Fettah; Zenciroğlu, Ayşegül; Dilli, Dilek; Beken, Serdar; Okumuş, Nurullah

2017-11-01

Aim To evaluate the relationship between serum 25-hydroxy vitamin D, 25 (OH) D, levels and retinopathy of prematurity. Methods and Results Serum 25 (OH) D levels were measured in 97 very low birth weight infants, prior to vitamin D supplementation. The development of retinopathy of prematurity and its treatment requirement were evaluated. At follow-up, retinopathy of prematurity developed in 71 (73.2%) infants. Serum 25 (OH) D levels were significantly lower in infants with retinopathy of prematurity than ones without retinopathy of prematurity ( P prematurity development [OR: 1.14, 95% CI (1.02-1.27), P = 0.02]. Conclusion Lower 25 (OH) D levels in the first days of life may be related to retinopathy of prematurity development and treatment requirement in premature infants.

Knowledge to Action - Understanding Natural Hazards-Induced Power Outage Scenarios for Actionable Disaster Responses

Science.gov (United States)

Kar, B.; Robinson, C.; Koch, D. B.; Omitaomu, O.

2017-12-01

The Sendai Framework for Disaster Risk Reduction 2015-2030 identified the following four priorities to prevent and reduce disaster risks: i) understanding disaster risk; ii) strengthening governance to manage disaster risk; iii) investing in disaster risk reduction for resilience and; iv) enhancing disaster preparedness for effective response, and to "Build Back Better" in recovery, rehabilitation and reconstruction. While forecasting and decision making tools are in place to predict and understand future impacts of natural hazards, the knowledge to action approach that currently exists fails to provide updated information needed by decision makers to undertake response and recovery efforts following a hazard event. For instance, during a tropical storm event advisories are released every two to three hours, but manual analysis of geospatial data to determine potential impacts of the event tends to be time-consuming and a post-event process. Researchers at Oak Ridge National Laboratory have developed a Spatial Decision Support System that enables real-time analysis of storm impact based on updated advisory. A prototype of the tool that focuses on determining projected power outage areas and projected duration of outages demonstrates the feasibility of integrating science with decision making for emergency management personnel to act in real time to protect communities and reduce risk.

Key Issues for the control of refueling outage duration and costs in PWR Nuclear Power Plants

International Nuclear Information System (INIS)

Degrave, Claude

2002-01-01

For several years, EDF, within the framework of the CIDEM1 project and in collaboration with some German Utilities, has undertaken a detailed review of the operating experience both of its own NPP and of foreign units, in order to improve the performances of future units under design, particularly the French-German European Pressurized Reactor (EPR) project. This review made it possible to identify the key issues allowing to decrease the duration of refueling and maintenance outages. These key issues can be classified in 3 categories Design, Maintenance and Logistic Support, Outage Management. Most of the key issues in the design field and some in the logistic support field have been studied and could be integrated into the design of any future PWR unit, as for the EPR project. Some of them could also be adapted to current plants, provided they are feasible and profitable. The organization must be tailored to each country, utility or period: it widely depends on the power production environment, particularly in a deregulation context. (author)

Ovarian failure due to cancer treatment and fertility preservation options

Directory of Open Access Journals (Sweden)

Soheila Aminimoghaddam

2016-04-01

Full Text Available Primary ovarian insufficiency (POI, commonly referred to premature ovarian failure, is defined as ovarian failure before the age of 40 years. It is the loss of ovarian function caused by a process directly affecting ovaries. Cancer therapy which includes surgery, radiotherapy, and chemotherapy influence ovarian function, leading to premature menopause and loss of fertility. POI is idiopathic in most cases (74-90%. The known causes, in addition to anticancer treatment, are other processes like chromosomal abnormalities, autoimmunity, and natural aging can result in secondary ovarian failure, which is detected by an increase in serum gonadotropin levels (FSH and LH. There are evident risks of POI in women treated for cancer. Those who receive anticancer treatments have an increased risk of developing POI. There by, anticancer drugs and radiation therapy are considered as the most common toxins of ovaries. Although cancer incidence rates in women less than 50 years old continue to increase during recent years, mortality rates are dramatically decreasing due to modern advances in treatment. Increasing numbers of survivors are now confronted with the long-term consequences of exposure to these treatments. The pool of primordial follicles in the ovary is fixed and any injury to the ovary can potentially reduce this ovarian reserve, effectively advancing the patient’s reproductive age, thus narrowing the window of reproductive opportunity. Ovarian failure occurs in a significant percentage of childhood cancer survivors and many of them will seek care for reproductive dysfunction. Nevertheless, Embryo cryopreservation, oocyte cryopreservation, ovary tissue cryopreservation, ovarian suppression and oophoro-pexy are some options to preserve fertility in these groups. As a result, having foreknowledge of potential treatment related ovarian failure will allow the physician to give a better counsel to patients and their family regarding the importance and

Spatial generalized linear mixed models of electric power outages due to hurricanes and ice storms

International Nuclear Information System (INIS)

Liu Haibin; Davidson, Rachel A.; Apanasovich, Tatiyana V.

2008-01-01

This paper presents new statistical models that predict the number of hurricane- and ice storm-related electric power outages likely to occur in each 3 kmx3 km grid cell in a region. The models are based on a large database of recent outages experienced by three major East Coast power companies in six hurricanes and eight ice storms. A spatial generalized linear mixed modeling (GLMM) approach was used in which spatial correlation is incorporated through random effects. Models were fitted using a composite likelihood approach and the covariance matrix was estimated empirically. A simulation study was conducted to test the model estimation procedure, and model training, validation, and testing were done to select the best models and assess their predictive power. The final hurricane model includes number of protective devices, maximum gust wind speed, hurricane indicator, and company indicator covariates. The final ice storm model includes number of protective devices, ice thickness, and ice storm indicator covariates. The models should be useful for power companies as they plan for future storms. The statistical modeling approach offers a new way to assess the reliability of electric power and other infrastructure systems in extreme events

Blood cell mitochondrial DNA content and premature ovarian aging.

Directory of Open Access Journals (Sweden)

Marco Bonomi

Full Text Available Primary ovarian insufficiency (POI is a critical fertility defect characterized by an anticipated and silent impairment of the follicular reserve, but its pathogenesis is largely unexplained. The frequent maternal inheritance of POI together with a remarkable dependence of ovarian folliculogenesis upon mitochondrial biogenesis and bioenergetics suggested the possible involvement of a generalized mitochondrial defect. Here, we verified the existence of a significant correlation between blood and ovarian mitochondrial DNA (mtDNA content in a group of women undergoing ovarian hyperstimulation (OH, and then aimed to verify whether mtDNA content was significantly altered in the blood cells of POI women. We recruited 101 women with an impaired ovarian reserve: 59 women with premature ovarian failure (POF and 42 poor responders (PR to OH. A Taqman copy number assay revealed a significant mtDNA depletion (P<0.001 in both POF and PR women in comparison with 43 women of similar age and intact ovarian reserve, or 53 very old women with a previous physiological menopause. No pathogenic variations in the mitochondrial DNA polymerase γ (POLG gene were detected in 57 POF or PR women with low blood mtDNA content. In conclusion, blood cell mtDNA depletion is a frequent finding among women with premature ovarian aging, suggesting that a still undetermined but generalized mitochondrial defect may frequently predispose to POI which could then be considered a form of anticipated aging in which the ovarian defect may represent the first manifestation. The determination of mtDNA content in blood may become an useful tool for the POI risk prediction.

[Birth weight distribution among premature infants and related social factors].

Science.gov (United States)

Guo, Li-jun; Ye, Rong-wei; Wang, Gui-xia; Wang, Juan; Li, Zhi-wen; Ren, Ai-guo

2009-12-01

To understand the distribution of birth weight among premature infants and the associated social factors. The study population consisted of 97 537 women who delivered singleton live birth of 20 to 41 gestational weeks in 4 counties/cities, Jiangsu and Zhejiang provinces, China from 1995 to 2000. Chi-square test was employed to test the difference of proportions between respective groups. One- way ANOVA was used to test the differences regarding the mean of gestational weeks at the first prenatal visit and the mean of prenatal visits between the two groups. Multivariate logistic regression was conducted to examine the factors associated with premature birth. Women aged 35 years had higher (8.8%) premature incidence than those aged less than 24 years (5.6%), 25 - 29 years (4.6%), or 30 - 34 years (4.5%, P premature incidence than those with height taller than 150 cm (5.0%). Women whose BMI were at least 28 and 24 - 28 had higher (5.5%, 5.5%) premature incidences than those whose BMI were 18.5 - 24.0 (5.0%), premature birth was 6.0% among women without previous pregnancy, higher than that among those women with 4 times of pregnancies (5.7%), 2 times of pregnancies (4.3%), and 3 times of pregnancies (4.0%). Parous women with at least two deliveries had higher (9.3%) premature incidence than the primiparous women (5.2%) and whose women with only one delivery (4.5%, P premature incidence than those who did not receive the service (6.1%). The mean times of prenatal visits among women with premature births was 8.53, less than that of those with full term delivery (10.97). Women with less than four times of prenatal visit had higher (18.9%) premature incidence than those with at least five prenatal visits (4.9%). Multivariate logistic regression showed that premature delivery risk was associated with age, height, BMI, gravidity, parity, early prenatal care, the mean of gestational weeks at first prenatal visit and the mean number of prenatal visits etc. Premature delivery

Energy markets : refinery outages can have varying gasoline price impacts, but gaps in federal data limit understanding of impacts.

Science.gov (United States)

2009-07-01

In 2008, GAO reported that, with : the exception of the period : following Hurricanes Katrina and : Rita, refinery outages in the United : States did not show discernible : trends in reduced production : capacity, frequency, and location : from 2002 ...

The distribution of patients who seek treatment for the complaint of ejaculating prematurely according to the four premature ejaculation syndromes.

Science.gov (United States)

Serefoglu, Ege Can; Cimen, Haci Ibrahim; Atmaca, Ali Fuat; Balbay, M Derya

2010-02-01

In addition to "lifelong" and "acquired" premature ejaculation (PE) syndromes, two more PE syndromes have recently been proposed: "Natural variable PE" and "premature-like ejaculatory dysfunction." The purpose of this study was to analyze the prevalence of the four PE syndromes among patients who were admitted to a urology outpatient clinic with the complaint of ejaculating prematurely. Between July 2008 and March 2009, patients admitted to a urology outpatient clinic with a self-reported complaint of PE were enrolled into the study. After taking a careful medical and sexual history, patients were classified as "lifelong,"acquired,"natural variable," PE or "premature-like ejaculatory dysfunction." In addition to medical and sexual history, self-estimated intravaginal ejaculatory latency times (IELTs) of patients were used in the classification of patients. A total of 261 potent men with a mean age of 36.39 +/- 10.45 years (range 20-70) were recruited into the study. The majority of the men was diagnosed as having lifelong PE (62.5%); the remaining men were diagnosed as having acquired (16.1%), natural variable PE (14.5%), or premature-like ejaculatory disorder (6.9%). The mean age of patients with acquired PE was significantly higher than the other groups (P = 0.001). No significant difference was observed for educational status or income level of patients in the different PE groups (P = 0.983 and P = 0.151, respectively). The mean self-estimated IELT for all subjects was 65.16 +/- 83.75 seconds (2-420 seconds). Patients with lifelong PE had significantly lower mean self-reported IELT, whereas the patients with premature-like ejaculatory dysfunction had the highest mean IELT (P = 0.001): (i) life-long PE: 20.47 +/- 28.90 seconds (2-120 seconds); (ii) aquired PE: 57.91 +/- 38.72 seconds (90-180 seconds); (iii) natural variable PE: 144.17 +/- 22.47 seconds (120-180 seconds); and (iv) premature-like ejaculatory dysfunction: 286.67 +/- 69.96 seconds (180-420 seconds

Comparison of bone density in amenorrheic women due to athletics, weight loss, and premature menopause.

Science.gov (United States)

Jones, K P; Ravnikar, V A; Tulchinsky, D; Schiff, I

1985-07-01

Studied was the peripheral bone density of 39 women (ages 18 to 43) with the diagnosis of secondary amenorrhea in an effort to define the population of amenorrheic women at risk for osteoporosis. Eight women had exercise-induced amenorrhea (athletes), 20 women had amenorrhea associated with weight loss, and 11 women had premature menopause. These diagnoses were made on the basis of history, physical examination, and luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin levels, and failure to have withdrawal bleeding after the administration of progestin. Twenty-five nonathletic, normally menstruating women served as control subjects. The peripheral bone density of the amenorrheic athletes (0.738 g/cm2 +/- 0.047) was not significantly different from that of the controls (0.726 g/cm2 +/- 0.044). The average bone density of the group with weight loss-associated amenorrhea (0.672 g/cm2 +/- 0.066) was significantly less than controls (P less than .005) as was that of the women with premature menopause (0.616 g/cm2 +/- 0.048, P less than .001). There was a significant correlation between months of amenorrhea and decrease in bone density (r = 0.506, P less than .001). From this study it was concluded that women with exercise-associated amenorrhea are not at significant risk for cortical bone loss as measured by direct photon absorptiometry. Women with weight loss-associated amenorrhea and women with premature menopause are at significant risk for bone loss when compared with normal controls.

Premature dental eruption: report of case.

LENUS (Irish Health Repository)

McNamara, C M

2011-08-05

This case report reviews the variability of dental eruption and the possible sequelae. Dental eruption of the permanent teeth in cleft palate children may be variable, with delayed eruption the most common phenomenon. A case of premature dental eruption of a maxillary left first premolar is demonstrated, however, in a five-year-old male. This localized premature dental eruption anomaly was attributed to early extraction of the primary dentition, due to caries.

Adequacy of published screening criteria for retinopathy of prematurity.

Science.gov (United States)

Taranath, Deepa A; Oh, Dickson D-S; Keane, Miriam C; Fabel, Helen; Marshall, Peter

2016-03-01

Criteria for screening preterm infants for retinopathy of prematurity vary around the world. We aimed to analyse the efficacy of alternative screening criteria. We collected retrospective data at a tertiary level neonatal nursery. Our participants were 1007 babies, born between 1997 and 2011, at prematurity. We determined whether disease would be detected using an alternative Australian screening model (gestational age prematurity is our main outcome. Using several of the alternative criteria, two neonates with clinically significant retinopathy of prematurity, one of whom required laser treatment to preserve sight, would not have been screened, and their disease may have gone undetected. Use of prematurity may risk clinically significant cases being missed and others may screen babies unnecessarily. Alternative criteria should be considered and '<30 weeks gestational age and/or <1500 g birth weight' appears a viable option. © 2015 Royal Australian and New Zealand College of Ophthalmologists.

Outage and BER analysis for ultrawideband-based WPAN in Nakagami-m fading channels

KAUST Repository

Mehbodniya, Abolfazl

2011-09-01

This paper presents a performance analysis of multiband orthogonal frequency-division multiplexing (MB-OFDM) in ultra wideband (UWB)-based personal area networks (UPANs). A UPAN consists of devices with different UWB technologies at the physical layer. Approximate expressions for the outage probability and average bit error rate (BER) are derived in closed form for the MB-OFDM target receiver, taking into account multi-user interference (MUI), as well as external interference in the form of time-hopping (TH) and direct-sequence (DS) UWB signals. © 2010 IEEE.

Long-term impact of prematurity on postnatal neurohormonal regulation

Directory of Open Access Journals (Sweden)

M. I. Ziborova

2016-01-01

Full Text Available This article considers the psychophysiological and neuroendocrine differences characteristic of premature children, which are as a result of long-term perinatal consequences. Particular emphasis is laid on the effects of the hypothalamic-pituitary-adrenocortical stress system, the performance of which is reprogramed during complicated pregnancy, labor, and postnatal period under pain stress due to medical manipulations. Being extremely sensitive to all these exposures, the brain of a premature infant develops during activation of the stress system and takes on a few distinctive properties in addition to independent neuroanatomical distinctions due to premature birth. The altered neurohormonal patterns revealed in very prematurely born children and adolescents involve the regulation of mental processes, behavior, metabolism, and circadian rhythms (sleep-wake regulation, which differ from those in their maturely born peers. These cases allow learning and behavior problems and lower cognitive estimates to be considered in normally developing children born extremely prematurely who have also hormonal dysregulation.

'Rush' type retinopathy of prematurity: report of three cases.

OpenAIRE

Nissenkorn, I; Kremer, I; Gilad, E; Cohen, S; Ben-Sira, I

1987-01-01

Three premature infants observed to develop severe stage III retinopathy of prematurity (ROP) at 3 to 5 weeks of age received immediate treatment by cryoablation and photocoagulation, with good results. The critical importance of the ophthalmic examination of premature babies from the age of 2 weeks, so as not to overlook such cases of 'rush' type ROP is stressed and the difficulty involved in treating such small neonates is discussed.

Ichthyosis prematurity syndrome: a well-defined congenital ichthyosis subtype

DEFF Research Database (Denmark)

Bygum, Anette; Westermark, Per; Brandrup, Flemming

2008-01-01

Ichthyosis prematurity syndrome is a rare syndrome characterized by the clinical triad of premature birth, thick caseous desquamating epidermis, and neonatal asphyxia. We describe two siblings with ichthyosis prematurity syndrome. The index patient was born at gestational week 34. Immediately aft...... in the stratum corneum and stratum granulosum. Diagnosing this syndrome is important to reassure parents, obstetricians, and pediatricians about its benign course after complications in the perinatal period....

Retinopathy of Prematurity: Clinical Features, Classification, Natural History, Management and Outcome.

Science.gov (United States)

Shah, Parag K; Prabhu, Vishma; Ranjan, Ratnesh; Narendran, Venkatapathy; Kalpana, Narendran

2016-11-07

Retinopathy of prematurity is an avoidable cause of childhood blindness. Proper understanding of the classification and treatment methods is a must in tackling this disease. Literature search with PubMed was conducted covering the period 1940-2015 with regards to retinopathy of prematurity, retrolental fibroplasia, its natural history, classification and treatment. The clinical features, screening and staging of retinopathy of prematurity according to International classification of retinopathy of prematurity (ICROP) has been included with illustrations. The standard current treatment indications, modalities and outcomes from landmark randomized controlled trials on retinopathy of prematurity have been mentioned. This review would help pediatricians to update their current knowledge on classification and treatment of retinopathy of prematurity. Screening for retinopathy of prematurity, in India, should be performed in all preterm neonates who are born <34 weeks gestation and/or <1750 grams birthweight; as well as in babies 34-36 weeks gestation or 1750-2000 grams birthweight if they have risk factors for ROP. Screening should start by one month after birth.

Premature Ejaculation and Utilization of Cognitive Techniques

Directory of Open Access Journals (Sweden)