bluuebunny/crossref_metadata_2025 huggingface dataset:
Tropical forests are thermally buffered despite intensive selective logging
Authors: Senior Rebecca A. , Hill Jane K. , Benedick Suzan , Edwards David P.
Published: October 2017

Tropical rainforests are subject to extensive degradation by commercial selective logging. Despite pervasive changes to forest structure, selectively logged forests represent vital refugia for global biodiversity. The ability of these forests to buffer temperature‐sensitive species from climate warming will be an important determinant of their future conservation value, although this topic remains largely unexplored. Thermal buffering potential is broadly determined by: (i) the difference between the “macroclimate” (climate at a local scale, m to ha) and the “microclimate” (climate at a fine‐scale, mm to m, that is distinct from the macroclimate); (ii) thermal stability of microclimates (e.g. variation in daily temperatures); and (iii) the availability of microclimates to organisms. We compared these metrics in undisturbed primary forest and intensively logged forest on Borneo, using thermal images to capture cool microclimates on the surface of the forest floor, and information from dataloggers placed inside deadwood, tree holes and leaf litter. Although major differences in forest structure remained 9–12 years after repeated selective logging, we found that logging activity had very little effect on thermal buffering, in terms of macroclimate and microclimate temperatures, and the overall availability of microclimates. For 1°C warming in the macroclimate, temperature inside deadwood, tree holes and leaf litter warmed slightly more in primary forest than in logged forest, but the effect amounted to <0.1°C difference between forest types. We therefore conclude that selectively logged forests are similar to primary forests in their potential for thermal buffering, and subsequent ability to retain temperature‐sensitive species under climate change. Selectively logged forests can play a crucial role in the long‐term maintenance of global biodiversity.
Resolution of international banks: Can smaller countries cope?
Authors: Schoenmaker Dirk
Published: October 2017

The stability of a banking system ultimately depends on the strength and credibility of the fiscal backstop. While large countries can still afford to resolve large global banks on their own, small and medium‐sized countries face a policy choice. This paper investigates the impact of resolution on banking structure. The financial trilemma model suggests that smaller countries can either conduct joint supervision and resolution of their global banks (based on single point of entry resolution) or reduce the size of their global banks and move to separate resolution of these banks' national subsidiaries (based on multiple point of entry resolution). Euro‐area countries are heading for joint resolution based on burden sharing, while the United Kingdom and Switzerland have implemented policies to downsize their banks.
What makes generalist mental health professionals effective when working with people with an intellectual disability? A family member and support person perspective
Authors: Weise Janelle , Fisher Karen R. , Trollor Julian N.
Published: October 2017

Background

Generalist mental health professionals are inadequately equipped to meet the rights of people with intellectual disability. A better understanding of the attributes of effective professionals may assist in the development of workforce capacity in this area.

Methods

Twenty‐eight family/support persons of people with intellectual disability participated in four focus groups. Thematic analysis was undertaken applying the Intellectual Disability Mental Health Core Competencies Framework.

Results

Participants described attributes that aligned with current professional expectations such as working together and new attributes such as differentiating between behaviour and mental health. An unexpected finding was the need for professionals to be able to infer meaning by interpreting multiple sources of information. Participants also wanted professionals to acknowledge their professional limitations and seek professional support.

Conclusion

Family/support persons identified a range of attributes of effective mental health professionals to support people with intellectual disability. Further research is necessary, particularly from the perspective of people with intellectual disability.
Improvements of adolescent psychopathology after insomnia treatment: results from a randomized controlled trial over 1 year
Authors: de Bruin Eduard J. , Bögels Susan M. , Oort Frans J. , Meijer Anne Marie
Published: October 2017

Background

Adolescent insomnia can be treated effectively with cognitive behavioural therapy for insomnia (CBTI). However, little is known about effects of CBTI on psychopathology in adolescents. This study aimed to investigate whether (a) CBTI improves psychopathology in Internet‐ (IT) and face‐to‐face group treatment (GT) compared to waitlist (WL), (b) improvement in psychopathology can be attributed to reduced insomnia, (c) improvement in psychopathology remains stable for up to 1 year.

Methods

One hundred and sixteen participants (age = 15.6 years, 25% males) with DSM‐5 insomnia, were randomly assigned to IT, GT or WL. Clinical trial registration: http://www.controlledtrials.com (ISRCTN33922163). Assessments of psychopathology, insomnia and objectively and subjectively measured sleep occurred at baseline, post‐treatment, and at 2‐, 6‐ and 12‐month follow‐up. Multilevel and mediation analyses were run to test hypotheses. The CBTI protocol, ‘Sleeping Smart’ for both IT and GT consisted of six weekly sessions and a booster session after 2 months.

Results

Psychopathology symptoms, insomnia and sleep problems as measured by actigraphy and sleep logs decreased substantially in IT and GT compared with WL at 2‐month follow‐up with medium to large effect sizes (ESs). Psychopathology symptoms remained stable or further improved for up to 12‐month follow‐up. ESs at 12‐month follow‐up for IT and GT were respectively: affective (d = −0.87 and −0.97), anxiety (d = −0.81 for IT), somatic (d = −0.38 and d = −0.52), oppositional (d = −0.42 for GT) and attention deficit hyperactivity disorder (ADHD) problems (d = −0.47 and −0.46). Mediation analyses indicated that reduction of insomnia symptoms after CBTI fully mediated the effects of CBTI on affective and anxiety problems, and partially mediated the effect on ADHD problems.

Conclusions

This is the first study demonstrating that Internet and face‐to‐face CBT for insomnia achieves long‐term reduction in adolescent psychopathology and does so by improving insomnia. This finding can have profound implications for youth mental health care.
Jaboticaba byproduct encapsulation by lyophilization: pH and food application stability
Authors: Rodrigues Letícia M. , Dos Santos Suelen S. , Bergamasco Rita C. , Madrona Grasiele S.
Published: October 2017

The study aimed to microencapsulate jaboticaba byproduct extract by lyophilization, followed by the characterization, pH stability and food application of the prepared microcapsules. The products were visualized by scanning electron microscopy and the yield, encapsulation efficiency (EE%), and bioactive compounds (high‐performance liquid chromatography) were determined. The major compounds found (in all samples) were cyanidin‐3‐glucoside, acids ellagic and gallic, and quercetin. The EE% was 80.0% and yield 67.2%. The capsules presented smooth surfaces and varied morphologies, such as broken glass of irregular sizes. The extracts revealed brighter and lighter‐colored solutions in low pH buffers, while microencapsulation protected the monomeric anthocyanins and phenolic compounds, particularly at pH 6.5. At 4 °C, maria‐mole desserts produced with the extract, showed a higher color variation (ΔE) than the product prepared with the microcapsules. Thus, microencapsulation may be an alternative to maintain the stability of the jaboticaba extract, as a way to reuse the agroindustrial byproduct.

Practical applications

The nutritional and functional properties of a vast biodiversity of plants (and their byproducts) have not yet been fully studied. Jaboticaba byproduct has great potential for economic exploitation and could be a valuable source of natural antioxidants, however, more studies of this byproduct, are required. Moreover, protecting the antioxidants during the fruit extraction process and storage, can improve the utilization and application of bioactives in food products. In this study, the extraction and microencapsulation of jaboticaba byproduct were realized. The results showed microencapsulation may be a feasible alternative to maintain the stability of the jaboticaba extract and provide a way to reuse the agroindustrial byproduct, as an ingredient in the food and, potentially, cosmetics and pharmaceutical industries.
Multisensory modulation of experimentally evoked perceptual distortion of the face
Authors: Dagsdóttir L. K. , Bellan V. , Skyt I. , Vase L. , Baad‐Hansen L. , Castrillon E. , Svensson P.
Published: October 2017

Background

Chronic oro‐facial pain patients often perceive the painful face area as “swollen” without clinical signs, that is a perceptual distortion (PD). Local anaesthetic (LA) injections in healthy participants are also associated with PD.

Objective

The aim was to explore whether PD evoked by LA into the infraorbital region could be modulated by adding mechanical stimulation (MS) to the affected area.

Methods

Mechanical stimulation was given with a brush and a 128‐mN von Frey filament. Firstly, sixty healthy participants were randomly divided into three groups: (i) LA control, (ii) LA with MS, (iii) isotonic solution (ISO) with MS as an additional control condition. To further examine the role of a multisensory modulation, an additional experiment was conducted. Twenty participants received LA with MS (filament) in addition to visual feedback of their distorted face. The results of the two experiments are presented together.

Results

All three LA groups experienced PD; per contra, PD was not reported in the ISO group. MS alone did not change the magnitude of PD: brush (P = .089), filament (P = .203). However, when the filament stimulation was combined with additional visual information of a distorted face, there was observable decrease in PD (P = .002).

Conclusion

The findings indicate the importance of multisensory integration for PD and represent a significant step forward in the understanding of the factors that may influence this common condition. Future studies are encouraged to investigate further the cortical processing for possible implications for PD in pain management.
The optimal minimum wage with regulatory uncertainty
Authors: Bennett John , Chioveanu Ioana
Published: October 2017

For two different regulatory standards, we examine the optimal minimum wage in a competitive labor market when the government is uncertain about supply and demand. Solutions are related to underlying supply and demand conditions, and to the extent of uncertainty and of rationing efficiency. With expected earnings maximization, greater uncertainty widens the range of parameter values for which a minimum wage should be set. With expected worker surplus maximization and sufficiently efficient rationing, a minimum wage should always be set. However, in both cases regulatory uncertainty may require a low minimum wage that may not bind in equilibrium.
Assessing global range expansion in a cryptic species complex: insights from the red seaweed genus Asparagopsis (Florideophyceae)
Authors: Zanolla Marianela , Altamirano María , Carmona Raquel , De la Rosa Julio , Souza‐Egipsy Virginia , Sherwood Alison , Tsiamis Konstantinos , Barbosa Ana Márcia , Muñoz Antonio Román , Andreakis Nikos
Published: October 2017

The mitochondrial genetic diversity, distribution and invasive potential of multiple cryptic operational taxonomic units (OTUs) of the red invasive seaweed Asparagopsis were assessed by studying introduced Mediterranean and Hawaiian populations. Invasive behavior of each Asparagopsis OTU was inferred from phylogeographic reconstructions, past historical demographic dynamics, recent range expansion assessments and future distributional predictions obtained from demographic models. Genealogical networks resolved Asparagopsis gametophytes and tetrasporophytes into four A. taxiformis and one A. armata cryptic OTUs. Falkenbergia isolates of A. taxiformis L3 were recovered for the first time in the western Mediterranean Sea and represent a new introduction for this area. Neutrality statistics supported past range expansion for A. taxiformis L1 and L2 in Hawaii. On the other hand, extreme geographic expansion and an increase in effective population size were found only for A. taxiformis L2 in the western Mediterranean Sea. Distribution models predicted shifts of the climatically suitable areas and population expansion for A. armata L1 and A. taxiformis L1 and L2. Our integrated study confirms a high invasive risk for A. taxiformis L1 and L2 in temperate and tropical areas. Despite the differences in predictions among modelling approaches, a number of regions were identified as zones with high invasion risk for A. taxiformis L2. Since range shifts are likely climate‐driven phenomena, future invasive behavior cannot be excluded for the rest of the lineages.
Control of biotin biosynthesis in mycobacteria by a pyruvate carboxylase dependent metabolic signal
Authors: Lazar Nathaniel , Fay Allison , Nandakumar Madhumitha , Boyle Kerry E. , Xavier Joao , Rhee Kyu , Glickman Michael S.
Published: October 2017

Biotin is an essential cofactor utilized by all domains of life, but only synthesized by bacteria, fungi and plants, making biotin biosynthesis a target for antimicrobial development. To understand biotin biosynthesis in mycobacteria, we executed a genetic screen in Mycobacterium smegmatis for biotin auxotrophs and identified pyruvate carboxylase (Pyc) as required for biotin biosynthesis. The biotin auxotrophy of the pyc::tn strain is due to failure to transcriptionally induce late stage biotin biosynthetic genes in low biotin conditions. Loss of bioQ, the repressor of biotin biosynthesis, in the pyc::tn strain reverted biotin auxotrophy, as did reconstituting the last step of the pathway through heterologous expression of BioB and provision of its substrate DTB. The role of Pyc in biotin regulation required its catalytic activities and could be supported by M. tuberculosis Pyc. Quantitation of the kinetics of depletion of biotinylated proteins after biotin withdrawal revealed that Pyc is the most rapidly depleted biotinylated protein and metabolomics revealed a broad metabolic shift in wild type cells upon biotin withdrawal which was blunted in cell lacking Pyc. Our data indicate that mycobacterial cells monitor biotin sufficiency through a metabolic signal generated by dysfunction of a biotinylated protein of central metabolism.
Memories of humiliation, cultures of resentment towards Edom and the formation of ancient Jewish national identity
Authors: Tebes Juan Manuel
Published: October 2017

While the impact of wars and national humiliations in the ancient Jewish cultural nationalism has been studied extensively, little has been written about the role of the related phenomena of cultures of resentment against foreigners or minority groups. Well before the Hellenistic period, the Jewish tradition had already created its own perfect enemy whose very name became synonymous of Israel's most malicious antagonist: Edom. This article aims to study the changing attitudes towards the Edomites/Idumaeans from the late Judaean kingdom to the Roman period using a long‐durée perspective, particularly the growth of memories of humiliation and feelings of resentment product of the alleged crimes of Edom during Judah's fall and exile.
Impact of the Late Triassic mass extinction on functional diversity and composition of marine ecosystems
Authors: Dunhill Alexander M. , Foster William J. , Sciberras James , Twitchett Richard J.
Published: October 2017

Mass extinctions have profoundly influenced the history of life, not only through the death of species but also through changes in ecosystem function and structure. Importantly, these events allow us the opportunity to study ecological dynamics under levels of environmental stress for which there are no recent analogues. Here, we examine the impact and selectivity of the Late Triassic mass extinction event on the functional diversity and functional composition of the global marine ecosystem, and test whether post‐extinction communities in the Early Jurassic represent a regime shift away from pre‐extinction communities in the Late Triassic. Our analyses show that, despite severe taxonomic losses, there is no unequivocal loss of global functional diversity associated with the extinction. Even though no functional groups were lost, the extinction event was, however, highly selective against some modes of life, in particular sessile suspension feeders. Although taxa with heavily calcified skeletons suffered higher extinction than other taxa, lightly calcified taxa also appear to have been selected against. The extinction appears to have invigorated the already ongoing faunal turnover associated with the Mesozoic Marine Revolution. The ecological effects of the Late Triassic mass extinction were preferentially felt in the tropical latitudes, especially amongst reefs, and it took until the Middle Jurassic for reef ecosystems to fully recover to pre‐extinction levels.
Pulmonary Langerhans cell histiocytosis “de novo” after lung transplantation
Authors: Gómez‐Román Javier , Zarrabeitia María Teresa , Santurtún Ana , Parra José Antonio , Azueta Etxebarría Ainara , Cifrian Jose M , Freire Salinas Javier
Published: October 2017

A pulmonary Langerhans cell histiocytosis is presented in a 40 year‐old woman two years after bilateral lung transplantation for emphysema without any signs of Langerhans cells proliferation in the explanted lungs. A microsatellite molecular analysis showed the proliferating cells were generated in a recipient cellular clone. The patient did not quit smoking after transplantation. No signs of disease were detected in the implanted lungs before surgery. Strict control of immunosupressive drug levels stabilized the disease. A “de novo” monoclonal origin of stem cells, probably from the bone marrow is suggested. The reason she did not develop disease in the native lungs is unknown, although we suggest an interaction between tobacco or some other antigens and local cellular receptors.
First evidence for the presence of aquaporins in stallion sperm
Authors: Bonilla‐Correal S , Noto F , Garcia‐Bonavila E , Rodríguez‐Gil JE , Yeste M , Miro J
Published: October 2017

Contents

Aquaporins (AQPs) are transmembrane proteins found in all cells and are responsible for the transport of water and small solutes. While these proteins have been found in the spermatozoa of humans, rodents, pigs and cattle, where not only do they play a role for the regulation of sperm volume but are also related with the sperm resilience to withstand freeze–thawing procedures, their presence in stallion sperm is yet to be reported. Therefore, the objectives of this work were as follows: (i) to determine whether AQP3, AQP7 and AQP11 are present in stallion sperm and (ii) to investigate whether the relative amounts of these three AQPs play any role in the cryopreservation success. With this purpose, a total of five ejaculates from healthy stallions were collected. Evaluation of sperm quality and immunoblotting against these three proteins were performed before and after cryopreservation. Immunoblots confirmed the presence of AQP3, AQP7 and AQP11 in all examined samples. Subsequently, ejaculates were classified as GFE (good) and PFE (poor freezability ejaculates), according to their sperm viability and motility at 0 and 2 hr post‐thaw. Relative AQP3 and AQP11 contents in stallion fresh semen were found to be significantly (p < .05) higher in GFE than in PFE. In conclusion, the current study has confirmed, for the first time, the presence of AQP3, AQP7 and AQP11 in stallion sperm. In addition, despite preliminary, our results suggest that AQP3 and AQP11 are involved in the resilience of stallion sperm to withstand cryopreservation. Ongoing research is aimed at increasing the sample size and includes immunolocalization studies.
Schooling and household welfare: The case of Sri Lanka from 1990 to 2006
Authors: Himaz Rozana , Aturupana Harsha
Published: October 2017

This paper looks at the effect schooling has had on household welfare in Sri Lanka during the 1990–2006 period, on average and across the welfare distribution. We account for the endogeneity of schooling using quantile instrumental variable estimation as developed in Chernozhukov, Fernández‐Val, and Kowalski (). We use pooled data from four cross‐sectional Household Income Expenditure Surveys. The results show that an extra year of schooling on the part of the most educated adult member in the household can increase welfare (proxied by real per capita consumption expenditure) by 3.8 percent on average. However, the effect varies considerably across the welfare distribution: At the lower end, around the 20th and 25th quantiles, an extra year of education increases welfare by 6 and 5 percent, respectively, while at the median it is around 3.5 percent. At the higher, 90th quantile it is much less, at 1 percent. Thus the marginal effect of schooling on welfare is significant and positive at all levels of the welfare distribution, but highest at the lower and middle quartiles. This result is different from findings in the literature that tend to show larger effects at higher quantiles, when endogeneity is uncorrected.
A daily diary investigation of the influence of early family adversity on social functioning during the transition to adulthood
Authors: Raposa Elizabeth B. , Hammen Constance
Published: October 2017

Early life stressors are associated with maladaptive social functioning in childhood and adolescence, but it is unclear whether and how the negative interpersonal effects of stress persist into adulthood. Daily diary surveys were used to examine young adults' social behavior and mood reactivity to social stressors as a function of experiences of early family adversity. Stressful early family environments predicted more daily reassurance seeking, but not aggression, withdrawal, or positive social behavior. Early family adversity also moderated the within‐person effects of social stressors on next‐day mood, such that individuals with high levels of adversity had elevated next‐day negative affect in response to higher than average social stress. Findings highlight the enduring impact of early adversity on social development, with implications for developing targeted policies and interventions.
Semiparametric time series regression modeling with a diverging number of parameters
Authors: Zheng Shengchao , Li Degao
Published: October 2017

Variable selection and error structure determination of a partially linear model with time series errors are important issues. In this paper, we investigate the regression coefficient and autoregressive order shrinkage and selection via the smoothly clipped absolute deviation penalty for a partially linear model with a divergent number of covariates and finite order autoregressive time series errors. Both consistency and asymptotic normality of the proposed penalized estimators are derived. The oracle property of the resultant estimators is proved. Simulation studies are carried out to assess the finite‐sample performance of the proposed procedure. A real data analysis is made to illustrate the usefulness of the proposed procedure as well.
Audit of appropriate use of platelet transfusions: validation of adjudication criteria
Authors: Etchells M. , Spradbrow J. , Cohen R. , Lin Y. , Armali C. , Lieberman L. , Cserti‐Gazdewich C. , Pendergrast J. , Callum J.
Published: October 2017

Background and Objectives

Platelet (PLT) transfusions must be used appropriately, as they are in chronic short supply, costly and risky to patients. The goals of this audit were to: (1) validate preset adjudication criteria through an audit of appropriateness at four large academic hospitals; (2) identify variability in appropriateness across medical services, physician specialties or hospital locations; and (3) inform logistical or educational interventions that may reduce inappropriate use.

Materials and Methods

A chart review of two hundred patients receiving PLT transfusions was performed. Fifty consecutive transfusion episodes per site were audited in detail. Each transfusion episode was independently adjudicated as appropriate or inappropriate by two transfusion specialists based on predetermined criteria.

Results

The adjudication criteria performed well with simple agreement of 95% (kappa statistic 0·83) between reviewers. Overall, 78% (95% CI: 72–84%) of PLT transfusions were adjudicated as appropriate, with results varying significantly by hospital site (range 62–94%). Prophylactic transfusions for non‐bleeding patients had the highest proportion of appropriateness (85%, n = 80), and therapeutic transfusions for bleeding patients had the lowest (73%, n = 99). The lowest levels of appropriate platelet transfusions were observed in the operating rooms (60%) and when ordered by the general surgery service (55%).

Conclusions

One in five platelet transfusions may be unnecessary, suggesting that interventions to improve PLT transfusion practice are warranted.
The risks and external effects of diabetic foot ulcer on diabetic patients: A hospital‐based survey in Wuhan area, China
Authors: Zhong Aimei , Li Gongchi , Wang Dan , Sun Yi , Zou Xinghua , Li Binghui
Published: October 2017

Diabetic foot ulcer (DFU) is a common complication observed in diabetic patients and affects diabetic patients in multiple ways. Severe DFU even leads to amputation in many cases. Early detection and intervention of DFU in diabetic patients can significantly relieve the pain caused by the ulcer and also keep patients from losing limbs in severe cases. In this study, the risks of diabetic patients getting DFU were estimated through a hospital‐based survey. This survey collected information from hospitalized diabetic patients in Wuhan City, Hubei Province, China, using a questionnaire. This investigation includes studies from two stages with 502 diabetic patients from 20 hospitals in Wuhan City. The results suggested that patients with a long history of diabetes are often associated with a high risk of DFU (χ2 = 11.428, p = 0.0007), smoking (χ2 = 8.386, p = 0.0007), diabetic complications (χ2 = 13.484, p < 0.0001), and especially patients with diabetic foot complications (χ2 = 57.6621, p < 0.0001). Foot lesions appeared to be important attributors to DFU since our data demonstrated close correlations between DFU and patients with calluses/corns (χ2 = 4.584, p = 0.0323), tinea pedis (χ2 = 4.030, p = 0.0447), and cracked skin (χ2 = 8.712, p = 0.0032). Only a small number of patients seek for the assistance from specialists, such as trimming toenails (3.4%), removing corn or calluses (1.4%) or treating wounds (11.78%), when they are suffering from foot problems. The findings of this study can potentially be utilized to develop an early DFU diagnostic method in diabetic patients and can provide objective evidence for suggesting that patients who are suffering from foot problems should seek professional help.
Safety and Operational I&C: Interface Management
Authors: Ciriello Antonio , Gupta Deeksha
Published: October 2017

A short overview will be given about the return of experience from past and current projects around the world for the interfaces between the safety and the operational instrumentation and control platforms (e.g., interactions, data flow and data diodes, separation, etc). Under the consideration of the applicable international standards which concern the mentioned interface, a general introduction will be provided about the implemented solutions for the modernization projects as well as for new build projects in the field of the instrumentation and control. Finally a conclusion about possible scenarios for future industrial projects will be provided too.
A Criterion for Evaluating Plastic Collapse Load: Plastic Work-Tangent Criterion
Authors: Zhang Ying
Published: October 2017

A new criterion: plastic work-tangent (PWT) criterion for evaluating plastic collapse load in pressure vessel design by analysis is presented in this paper. According to the plastic work-load curve, when the tangent variation is less than a given value in the plastic phase, the corresponding load is the plastic collapse load. Application of the proposed criterion is illustrated by considering the elastic-plastic response of lower head of reactor pressure vessel (RPV) and nozzle intersection of RPV. It is proposed that this is because the PWT criterion more conveniently to use in finite element soft ANSYS and more efficiently to evaluate the plastic collapse load.
Torsional Vibration Monitoring on Half-Speed Turbine of Nuclear Power Plant
Authors: Li Zhaojie , Zhao Pengcheng , Ni Qiuhua , Han Xuejie , Dong Xiangxiang
Published: October 2017

There are less monitoring and analysis about torsional vibration on half-speed turbine of nuclear power plant. It becomes more important because torsional vibration comes to expose on half-speed turbine conditions occurred by power grid fault or fluctuation. Based on an analysis of half-speed turbine conditions, this paper gives the turbine rotor’s torsional character, such as natural frequency, dangerous cross-section and S-N curve. This paper introduces torsional angle measurement in order to monitor torsional vibration, and the structure of torsional vibration monitoring system.
CANDU PHWR Feeder Pipe FAC Mitigation Design Modification and Validation During Operation
Authors: Jiongran Tang , Junmin Shang , Yue Yang , Jianzhong Yuan
Published: October 2017

Flow accelerated corrosion (FAC) is the main reason for Feeder pipe wall thinning in CANDU pressured heavy water reactor (PHWR). Atomic Energy of Canada Limited (AECL) made design modification for Third Qinshan Nuclear Power Plant (TQNPP) to mitigate Feeder pipe FAC rate by increasing Cr content to more than 0.2 wt % and control primary heat transport system (PHTS) pH value between 10.2–10.4, more than 4 years laboratory verification test proved the modification was effective. More than 10 years in-service inspection performed by TQNPP proved that real Feeder pipes FAC rate is less than designed value; TQNPP Feeder pipe can meet the design life and even extend the service life.
The Safety Constraints and Evaluation of I&C Algorithm Configuration Based on SCADE Platform
Authors: Liu Hua , Yang Xiao-Hua , Liu Zhao-hui , Liu Jie , Yan Shi-yu , Li Meng , Chen Zhi
Published: October 2017

Algorithm library plays an important role in digital instrument control system. In the design process, software testing and safety verification are focused on safety and reliability of the algorithm library. The generation of trip that is a shutdown signal is applied based on the basic algorithms library of SCADE platform. A new standpoint is proposed. The safety constraints are mainly focus on the configured parameters. The configured parameters are important to the safety and reliability. Relations of parameters among the different modules are very complex. Parameters are easy to be wrongly configured in the design process. The correct or mistakes of the parameters must be considered and checked. The analysis process of safety constraints is established. The algorithm module invariables and constraint rules are concluded according to the functions of each module, inputs and outputs, parameter description in the library. The typical test cases are generated by the correct rules. Safety constraints and analysis have enough operability.
Conceptual Formation of Advanced HIS Design Method for Digital I&C + HMIT
Authors: Yoshikawa Hidekazu , Ma Zhanguo , Nawaz Amjad , Yang Ming
Published: October 2017

A new conceptual frame of how to design and validate a digital HIS (human interface system) on an innovative numerical simulation basis is proposed for the support of plant operators’ supervisory control of various types of automated complex NPPs (nuclear power plants). The proposed conceptual framework utilizes the object-oriented AI softwares for plant DiD (defense-in depth) risk monitor with the combination of nuclear reactor accident simulation by an advanced nuclear safety analysis code RELAP5/MOD4 and severe accident analysis code MAAP. The developed conceptual frame proposed in this paper will be applied for an example practice for the SBLOCA (small break loss of coolant accident) case of passive safety PWR (pressurized water reactor) AP1000.
Measurement Method of Equivalent Water Level for Nuclear Steam Generator Based on Data Fusion
Authors: Li Xianling , Ke Zhiwu , Tao Mo
Published: October 2017

The nuclear U-tube steam generator (UTSG) is a key component for nuclear power plant, and the water level of UTSG must maintain a desired value. In order to overcome the impact of the false water level, an equivalent water level is proposed based on data fusion to simplify the water level control of UTSG. The equivalent water level is composed of steady and dynamic compositions, which are got through the water level sensor of UTSG and flow rate sensors for feed water and steam of UTSG respectively. The steady and dynamic compositions are generated by a low-pass filter and a high-pass filter according to the measuring data characteristics on frequency domain. The false water level characteristics of UTSG have been removed through the equivalent water level application, and then the impact of non-minimum phase characteristic of UTSG has been weakened remarkably. A simulation of water level control is conducted based on the equivalent water level, and the result indicates that a simple PID controller can make the UTSG run with a satisfied water level control performance. It is usually difficult to gain a satisfied control effect through a simple PID controller without equivalent water level, so the measurement method of equivalent water level will benefit the operation of UTSG by simplifying the control process obviously.
Exploration on Ranking Obsolescence Issues of High Priority for Nuclear Power Plant Based on AHP
Authors: Yu Wenmin , Gui Chun , Tao Ge , Lv Fangming
Published: October 2017

Analytic Hierarchy Process (AHP) is applied in this paper to rank obsolescence issues of high priority for nuclear power plants. At first, phenomena of obsolescence issues in nuclear power plants and characteristic of AHP is introduced in this paper; then it is explained and explored to apply AHP to solve the problem. Finally, an application is exampled using weighted sum model and weighted product model as well as AHP to solve the problem. The difference is compared and analyzed to reflect the plant’s concern. Using analytic hierarchy process to rank obsolescence issues for nuclear power plants provides interesting perspective and important support for the decision to select the issues that applied resource is allocated.
Control System Design for NuScale
Authors: Wang Kai , Sun Peiwei
Published: October 2017

NuScale is an advanced light water reactor with 50MWe. In its design, there is no coolant pump and the reactor is passively cooled. Integral design is adopted. In the pressure vessel, there are reactor core, steam generators and pressurizer. The coolant inventory is large and it takes more time to respond to disturbances. Once-through steam generator is adopted and superheated steam can be generated and sent to turbine. The water volume in the steam generator is small and it is very sensitive to disturbances. The different designs in the NuScale make its dynamic characteristics unique. Therefore, it is necessary to develop a dynamic model to study its dynamic behaviours and the control system can be further designed.

A dynamic model of NuScale is developed using Matlab/Simulink. The plant model includes reactor core model, helical coil steam generator model, pressurizer model and turbine model. A steady-state simulation is carried out and the results are compared with its design parameters. The largest relative error is 0.91%, which proves that the dynamic plant model developed is correct. Control systems are considered: reactor power, coolant pressure and pressurizer pressure control systems. The control rods are applied to regulate the reactor power and average coolant temperature. The spray and heater in the pressurizer is used to adjust the coolant pressure. The feedwater control is the most complex. Feedwater flow rate is adjusted to control the steam pressure and meanwhile the feedwater flow should be in accordance with the average coolant temperature. Therefore, average coolant temperature is considered in the feedwater control. PI controllers are selected and the gains are tuned to match the control requirements. Different load patterns are introduced to test the control system performance.
Small Pressurized Water Reactor (SPWR) Simulation Platform Development for its Design Verification
Authors: Sun Peiwei , Zhao Huanhuan , Zhang Jianmin
Published: October 2017

Small pressurized water reactors (SPWRs) are under development in the world. Lots of efforts have been made to the Research & Development. SPWR has its unique design features. The integral design is adopted. The reactor, coolant pump and steam generator are in the reactor vessel. The coolant inventory is large. Once-through steam generator is chosen. The pressurizer is also large in the volume. Because many years operation experiences of commercial PWRs, some old operation strategies may be modified or new strategies are derived for the new development. When the operation strategies are chosen, a simulation platform is needed to verify whether they are suitable for SPWRs. In this paper, an SPWR simulation platform is developed to verify the operation strategies of SPWR.

The platform is developed based on an engineering simulator and Relap5 has been integrated in the simulator. Operation transient or accident scenarios can be simulated with the simulator. To improve the operation flexibility and implementation of control logics, the engineering simulator is couple with MATLAB/Simulink using shared memory technology. Shared memory is an efficient means of passing data between programs. The dynamic data exchange and simulation time synchronization methods are carefully treated. To verify the platform, an SPWR with its control system is modeled with the platform and the simulator. The thermal-hydraulic modeling of the SPWR is carried out using Relap5. The preliminary SPWR control system is designed with conditional proportional-integral-derivative (PID) controllers and implemented in MATLAB/Simulink. Abrupt load changes are simulated to evaluate the performance of the platform. The results obtained from two different platforms match well with each other. It is proved that the coupling is successfully and the platform can simulate the transient behavior of the SPWR with its control system.
Transition From Time–Based Preventive Maintenance to Condition–Based Maintenance
Authors: Xiaonian Liu , Liangsheng Wang
Published: October 2017

An optimized maintenance strategy is being pursued in the nuclear power industry, so as to reduce the maintenance cost and improve equipment reliability. Transition from time-based preventive maintenance (TBM) to Condition-based Maintenance (CBM) or Predictive Maintenance (PdM) is being set as a site initiative by different utilities. This paper analyzes the key elements a plant should focus on to achieve a successful CBM transition; discusses the implementation steps and matters needing attention for the pilot project of CBM transition; and depicts precursors for CBM such as CBM equipment scope screening, equipment failure history collection, failure mode and degradation mechanism analysis, monitoring parameters and frequency setting, CBM result evaluation, and CBM planning. The paper also discusses the impacts and challenges of CBM transition campaign to the existing production scheme.
In-Service Inspection Technology Research on CANOPY Seal Weld of Control Rod Drive Mechanism in PWR
Authors: Lifeng Zhou , Zhaoyu Cheng , Jiafan Cai , Yi Tang
Published: October 2017

The cracking of CANOPY Seal Weld (CSW) of the Control Rod Drive Mechanism (CRDM) ever occurred and led to Boric acid solution leakage in nuclear power plant worldwide. The failure analysis on above failure CSW shows that stress corrosion crack (SCC) is main failure mode of CSW, and the crack usually originate from the weld root and grows along weld or HAZ under PWR service environment.

The CSW structure parameter presented here are as following, the wall thickness is 2–3 mm, radius of curvature of cross-section is 6–12 mm, and the gyration radius is 50–100mm. In the latest year, CSW is required to implement surface examination (i.e. Visual Test or Penetration Test) during the plant outage. The flaw is that the CSW won’t be repaired till its failure is detected; therefore effective preventive maintenance can’t be performed. The specific inspection technology is developed for NDT volume testing method, aiming to detect the root crack occurred in weld and its adjacent base metal.

This paper introduces the CSW structure, in-service inspection requirements, and technical solutions. The NDT technology corresponding UT, ET and CCTV was finally applied as applicable technical solution with automatic scanning devices to detect CSW crack. Ultrasonic inspection technology uses high-frequency water immersion focusing probes with frequency higher than 10MHz which is investigated to detect the defect in the weld root area. Meanwhile, Eddy current inspection technology is applied to detect the surface crack or subsurface crack with orthogonal difference array probes, which helps to distinguish false signals detected by UT in outer surface. Ultrasonic inspection technical solutions based on high-frequency water immersion focusing methods and the key technical parameters are discussed emphatically in this paper. By testing on blocks with characteristic artificial reflectors, characteristic rule of ultrasonic signals in different areas and sizing methods for crack is investigated respectively. It show that UT has higher detecting sensitivity for crack of where the height reaches 0.5mm and the length reaches 4mm, and sizing is accuracy and reliable for crack when the height over than 1 mm and the length over than 4mm.

CSW is not incorporated in-service scope referring to ASME code or Chinese in-service code, and the acceptance criterion of weld flaw is also not found. So, the integrity shall be evaluated as far as CSW with flaw is concerned. Thus, the stress analysis and temperature field are carried out on the CSW mentioned above, and the structural integrity assessment is simultaneously performed based on ASME code. Finally, the acceptance criteria are recommended for both volumetric and planar flaw.
Confluent Modeling of Heterogeneous Safety and Operational I&C Systems
Authors: Parekh Mithil , Gao Yuan , Jockenhoevel-Barttfeld Mariana , Waedt Karl
Published: October 2017

Individual systems or groups of systems related to the safety and operational I&C, and Electrical Systems (ES) are gradually replaced in existing Nuclear Power Plants (NPPs) as part of modernization projects. Modernizations are usually scheduled over multiple years. Different automation platform generations and safety-related product families are deployed to progressively replace legacy systems. Typically, each of the new I&C platforms and products have their own set of engineering tools.

One challenge for the modernization of installed systems is the safety and security approval of these heterogeneous systems by regulatory bodies. A NPP consists of systems manufactured by different vendors which target different application domains, like Category A according to IEC 61226 for a Reactor Protection System, Category C for some Control Room Data Processing Systems or non-classified for auxiliary systems. Thus, replacing a legacy system by introducing a new one might bring in unknown risks, especially when the new system has more complex interfaces, e.g. when replacing an analog system by a digital system. Moreover, considering the time and budget limitations, commercial-off-the-shelf (COTS) hardware and software are also involved in modernization projects. In contrast to specialized equipment, vulnerabilities for COTS are widespread. On the other hand, existing security measures/mitigations are also required to reflect the system’s changes, e.g. mitigations for known vulnerabilities of COTS systems.

In order to make an overall and integrated safety analysis after a system change in the frame of a modernization project, it is necessary to jointly consider these I&C systems targeting different application domains, in addition to the physical aggregates, like sensors, pumps and valves that interact with the physical processes.

The restrictive deployment of wireless technologies may also be modeled and analyzed. While wireless is not deployed by legacy systems, it is being covered by new nuclear IEC standards, as some utilities intend to simplify selected I&C maintenance procedures that involve temporary data collection. The key modeling concepts consider new developments in the critical infrastructure and industrial automation domain. With the integrated modeling approach, different disciplines can be addressed, like probabilistic and deterministic safety analyses, security assessments, need for testing and specialized trainings.
The Construction of Abnormal Event Recognition Expert System for HTR NPP
Authors: Xu Xiaona , Huang Xiaojin
Published: October 2017

In order to meet the needs in the development of Computerized Operating Procedures System of HTR NPP, an abnormal event recognition expert system is built for abnormal event operating procedures entrance monitoring of HTR NPP, using the method of fuzzy Petri net which has excellent graphic description ability and rigorous mathematical theory, in view of the problems existing in traditional expert system such as weak knowledge expression ability and low reasoning efficiency. Compared with the traditional methods, method in this paper has great advantages in strengthening the structural features and knowledge expression ability, improving the reasoning efficiency and convenient for computer programming. The simulation of a typical case of abnormal events recognition verifies the feasibility and effectiveness of the designed system, laying the foundation for the development of COPS of HTR NPP.
Vibration Alarm Analysis and Treatment of Main Coolant Pump in Nuclear Power Plant
Authors: Li Zhen , Du Pengcheng , Ma Gujian
Published: October 2017

The structure of main coolant pump in a nuclear power plant and vibration alarm are introduced. Vibration analysis and trouble diagnosis have been carried out. It shows that pump shaft vibration is mainly composed of running frequency (1×) and half of running frequency (0.5×), motor shaft vibration is just composed of 1×. The vibration fluctuation in pump shaft is caused by the variation of amplitude in 0.5×. Based on vibration analysis result, the fault investigation has been launched, in which it includes installment, measurement, dynamic balance and pump design. After detailed investigation, the excessive vibration was induced by the dynamic unbalance of pump shaft and unsteady vortex of shaft seal water. The research for treatment has been implemented on dynamic balance and seal water flow. It is suggested to increase the seal water flow to control vibration fluctuation. The result shows that this method is effective, economical, safe, and very easy to implement for suppressing flash vibration alarm.