bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasticity and genetic adaptation mediate amphibian and reptile responses to climate change
Authors: Urban Mark C. , Richardson Jonathan L. , Freidenfelds Nicole A.
Published: October 2013

Phenotypic plasticity and genetic adaptation are predicted to mitigate some of the negative biotic consequences of climate change. Here, we evaluate evidence for plastic and evolutionary responses to climate variation in amphibians and reptiles via a literature review and meta‐analysis. We included studies that either document phenotypic changes through time or space. Plasticity had a clear and ubiquitous role in promoting phenotypic changes in response to climate variation. For adaptive evolution, we found no direct evidence for evolution of amphibians or reptiles in response to climate change over time. However, we found many studies that documented adaptive responses to climate along spatial gradients. Plasticity provided a mixture of adaptive and maladaptive responses to climate change, highlighting that plasticity frequently, but not always, could ameliorate climate change. Based on our review, we advocate for more experiments that survey genetic changes through time in response to climate change. Overall, plastic and genetic variation in amphibians and reptiles could buffer some of the formidable threats from climate change, but large uncertainties remain owing to limited data.
Equine grass sickness in a donkey
Authors: Pirie R. S.
Published: October 2013

See also article by Mellor et al.
Does Corporate Social Responsibility (CSR) Improve Credit Ratings? Evidence from Geographic Identification
Authors: Jiraporn Pornsit , Jiraporn Napatsorn , Boeprasert Adisak , Chang Kiyoung
Published: October 2013

We show that a firm's CSR policy is significantly influenced by the CSR policies of firms in the same three‐digit zip code, an effect possibly due to investor clienteles, local competition, and/or social interactions. We then exploit the variation in CSR across the zip codes to estimate the effect of CSR on credit ratings under the assumption that zip code assignments are exogenous. We find that more socially responsible firms enjoy more favorable credit ratings. In particular, an increase in CSR by one standard deviation improves the firm's credit rating by as much as 4.5%.
Diversity increases carbon storage and tree productivity in Spanish forests
Authors: Ruiz‐Benito Paloma , Gómez‐Aparicio Lorena , Paquette Alain , Messier Christian , Kattge Jens , Zavala Miguel A.
Published: October 2013

Aim

Biodiversity loss could reduce primary productivity and the carbon storage provided by forests; however, the mechanisms underpinning the effects of biodiversity on multiple ecosystem functions are not completely understood. Spanish forests are of particular interest because of the broad variation in environmental conditions and management history. We tested for the existence of a relationship between diversity effects and both carbon storage and tree productivity, and examined the relative importance of complementarity and selection mechanisms in a wide variety of forests, from cold deciduous Atlantic to xeric Mediterranean evergreen forests.

Location

Continental Spain.

Methods

We used c. 54,000 plots of the Spanish Forest Inventory and maximum likelihood techniques to quantify how climate, stand structure and diversity shape carbon storage and tree productivity. Diversity effects included both complementarity and selection mechanisms, measured respectively through functional diversity and functional identity measures.

Results

Diversity had a significant effect on both carbon storage and tree productivity, even when controlling for confounding factors of climate and stand structure. A consistent positive effect of functional diversity on carbon storage and tree productivity was observed in all seven forest types studied. This relationship was not linear, and the largest changes in carbon storage and tree productivity were observed at low levels of functional diversity. However, the importance of complementarity effects was not consistent with the productivity of different forest types. Selection effects were particularly important in deciduous and Mediterranean pine forests, but had very little effect on mountain pines.

Main conclusions

We found a generally positive effect of diversity on carbon storage and tree productivity, supported by both complementarity and selection mechanisms. Thus, both functionally diverse forests and functionally important species should be maintained to adequately preserve and promote key ecosystem functions such as carbon storage and tree productivity.
Production of a high‐protein meal and fermentable sugars from defatted soybean meal, a co‐product of the soybean oil industry
Authors: Luján‐Rhenals Deivis , Morawicki Ruben O. , Mendez‐Montealvo Guadalupe , Wang Ya‐Jane
Published: October 2013

The goal of this research was to produce a high‐protein meal by treating defatted soybean meal, a by‐product of soybean oil production, with dilute acid. Treatments were a mild hydrolysis at 80 °C with sulphuric acid at concentrations ranging from 0.5% to 2.0% (w/v) and times varying from 1 to 16 h that were arranged according to a central composite rotatable experimental design. The end products were an enhanced‐protein meal and a carbohydrate concentrate of fermentable and nonfermentable sugars. The highest protein content rise, from 48% to 58%, was for treatments with concentrations of acid ranging between 1.2% and 1.7% and times between 1.0 and 2.6 h. The maximum yield of fermentable sugar was 21.0% d.b. at 2.0% H2SO4 and treatments of at least 6 h. The conditions that provide a highest protein and sugar contents were the treatments with concentrations of sulphuric acid ranging from 0.9 to 1.9% H2SO4 for 1–4 h.
Can the sprouting process applied to wheat improve the contents of vitamins and phenolic compounds and antioxidant capacity of the flour?
Authors: Žilić Slađana , Basić Zorica , Hadži‐Tašković Šukalović Vesna , Maksimović Vuk , Janković Marijana , Filipović Milomir
Published: October 2013

The content of tocopherols, B vitamins, as well as free soluble, soluble conjugated and insoluble bound phenolic compounds was determined in untreated, steeped and sprouted wheat grains. Antioxidant capacity of whole wheat grains and their phenolic fractions was also evaluated. Sprouting significantly increased the levels of tocopherols, niacin, riboflavin, as well as free and bound phenolic compounds improving nutritional value and antioxidant capacity of wheat grains/flour. After sprouting for 5 days, the content of total phenolics, flavonoids and ferulic acid calculated as the sum of its fractions was increased by 9.9, 30.7 and 21.6%, respectively. The content of α‐, β+γ‐ and δ‐tocopherols was increased for 3.59‐fold, 2.33‐fold and 2.61‐fold respectively, while the content of niacin, as predominant B vitamin, was increased for 1.19‐fold after sprouting. The total antioxidant capacity of untreated, steeped and sprouted whole wheat grains was 19.44, 20.37 and 22.70 mmol Trolox Eq/kg, respectively. Sprouted wheat, as a rich source of bioavailable phytochemicals, should be used to improve the nutritional quality of food.
Sunitinib‐related interstitial pneumonia after treatment with temsirolimus: A case of possible recall phenomenon
Authors: Kushima Hisako , Ishii Hiroshi , Kadota Jun‐ichi
Published: October 2013

A 55‐year‐old Japanese man was admitted to Oita University Hospital (Oita, Japan) for pyrexia, malaise and dyspnea, and abnormal shadows on chest radiographs. He had started receiving sunitinib (37.5 mg a day for 3 weeks, followed by a 3‐week break before beginning the next dosing cycle) for metastatic renal cell carcinoma after the improvement of temsirolimus‐induced interstitial pneumonia. Sunitinib is a multiple tyrosine kinase receptor inhibitor approved for the treatment of metastatic renal cell carcinoma, and the most common clinical adverse effects of sunitinib are diarrhea, mucositis, stomatitis, hypertension, rashes and altered taste. We herein report a rare case of sunitinib‐related interstitial pneumonia after treatment with temsirolimus for metastatic renal cell carcinoma. This case suggests the possibility of recall phenomenon of drug‐induced pneumonia during the administration of additional chemotherapy.
The role of pro‐resolution lipid mediators in infectious disease
Authors: Russell Clark D. , Schwarze Jürgen
Published: October 2013

Inflammation is an essential host defence against infection, but can be damaging when excessive. Resolution of inflammation is an active process, and the pro‐resolution effects of lipoxins, resolvins and protectins have received significant interest. Here, we review emerging data on the role of these lipid mediators in infectious disease. Lipoxins influence host control of Mycobacterium tuberculosis, Toxoplasma gondii, Trypanosoma cruzi and Plasmodium berghei cerebral malaria in mice. Their effects are protective in toxoplasmosis, T. cruzi infection and cerebral malaria but detrimental in tuberculosis; related to the balance between pathogen‐control and excessive immune response. Topical lipoxin abrogates the tissue damage seen in a rabbit model of Porphyromonas gingivalis periodontitis. The increased virulence of H5N1 influenza A virus in mice correlates with reduced expression of SOCS2, required to mediate the effects of lipoxin. Mice unable to synthesize lipoxin suffer increased lung pathology during respiratory syncytial virus infection. Protectin suppresses influenza A virus replication in vitro and increases survival in a mouse model of severe influenza infection. Resolvins were investigated in a number of animal models of systemic bacterial infection, and were found to enhance phagocytic clearance of bacteria, reduce inflammation severity, promote neutrophil apoptosis, modulate neutrophil chemotaxis and importantly, reduce mortality. Interestingly, resolvin also enhances the antibacterial effect of ciprofloxacin and vancomycin. Topical resolvin application reduces the severity of herpes simplex virus ocular infection in mice. If the effects of these mediators translate from pre‐clinical studies into successful clinical trials, they represent promising new strategies in managing infectious disease.
Relationship Between Left Ventricular Geometry and Soluble ST2 in a Cohort of Hypertensive Patients
Authors: Ojji Dike B. , Opie Lionel H. , Lecour Sandrine , Lacerda Lydia , Adeyemi Olusoji , Sliwa Karen
Published: October 2013

Left ventricular (LV) hypertrophy (LVH) is classified according to geometric pattern into 4 types: concentric hypertrophy, eccentric hypertrophy, concentric remodeling, and normal geometry. Prevalence of death and cardiovascular complications associated with hypertension depend on the geometric pattern. Although soluble ST2 levels, a novel cardiac biomarker of mechanical strain is increased in hypertension, the relationship with hypertensive LV geometric patterns has not been studied. The authors investigated the relationship between soluble ST2 levels and LV geometric patterns in a cohort of hypertensive patients. LVH was considered present when echocardiographic LV mass index exceeded 49.2 g/m2.7 in men and 46.2 g/m2.7 in women. Patients with concentric hypertrophy had higher soluble ST2 levels compared with patients with normal geometry (20.4±8.4 ng/mL vs 14.3±5.4 ng/mL, P<.002). Therefore, soluble ST2 level is not only affected by hypertensive LV, but may be a future biomarker in differentiating concentric hypertrophy from normal geometry in hypertension.
Does EEG‐neurofeedback improve neurocognitive functioning in children with attention‐deficit/hyperactivity disorder? A systematic review and a double‐blind placebo‐controlled study
Authors: Vollebregt Madelon A , van Dongen‐Boomsma Martine , Buitelaar Jan K , Slaats‐Willemse Dorine
Published: October 2013

Background

The number of placebo‐controlled randomized studies relating to EEG‐neurofeedback and its effect on neurocognition in attention‐deficient/hyperactivity disorder (ADHD) is limited. For this reason, a double blind, randomized, placebo‐controlled study was designed to assess the effects of EEG‐neurofeedback on neurocognitive functioning in children with ADHD, and a systematic review on this topic was performed.

Methods

Forty‐one children (8–15 years) with a DSM‐IV‐TR diagnosis of ADHD were randomly allocated to EEG‐neurofeedback or placebo‐neurofeedback treatment for 30 sessions, twice a week. Children were stratified by age, electrophysiological state of arousal, and medication use. Neurocognitive tests of attention, executive functioning, working memory, and time processing were administered before and after treatment. Researchers, teachers, children and their parents, with the exception of the neurofeedback‐therapist, were all blind to treatment assignment. Outcome measures were the changes in neurocognitive performance before and after treatment.

Clinical trial registration: www.clinicaltrials.gov: NCT00723684.

Results

No significant treatment effect on any of the neurocognitive variables was found. A systematic review of the current literature also did not find any systematic beneficial effect of EEG‐neurofeedback on neurocognitive functioning.

Conclusion

Overall, the existing literature and this study fail to support any benefit of neurofeedback on neurocognitive functioning in ADHD, possibly due to small sample sizes and other study limitations.
Morphological enhancement of microscopy mineral image using opening‐ and closing‐based toggle operator
Authors: BAI X.
Published: October 2013

To enhance unclear microscopy mineral images, an algorithm based on toggle operator using opening and closing is proposed in this paper. Firstly, the specified toggle operator using opening and closing through designing the selection rules is analysed. Secondly, after importing the multiscale theory into the specified toggle operator, useful mineral image features, especially the mineral details, are extracted using the multiscale theory‐based toggle operator. Finally, the mineral image is enhanced through the strategy of enlarging the contrast between the extracted bright and dark image features. Experimental results on different types of mineral images verified that the proposed algorithm could effectively enhance mineral images and performed better than some other algorithms. The enhanced mineral image is clear and contains rich mineral details, whereas the grey scale distribution of the original mineral image is appropriately maintained. This would be useful for the further mineral analysis. Therefore, the proposed algorithm could be widely used for image‐based mineral applications.
Perinatal common mental disorders and child survival in Ethiopia
Authors: Adewuya Abiodun O , Hanlon Charlotte , Medhin Girmay , Dewey Michael , Alem Atalay , Worku Bogale , Prince Martin
Published: October 2013

Aims

The study aims to evaluate the impact of perinatal common mental disorders (CMDs) on child mortality up to 3.5 years in a demographic surveillance site at Butajira, Ethiopia.

Methods

One thousand sixty‐five eligible women were assessed for CMD in the third trimester of pregnancy and at 2 months post‐delivery using the Self‐Reporting Questionnaire. We derived a four‐level categorical exposure variable for the course of perinatal CMD. The outcome measure was child death recorded from 1 month after the postnatal assessment up to 3.5 years. Potential confounders and mediators were evaluated.

Results

The cumulative child mortality rates were 62.6/1000 at 1 year and 82.5/1000 at 3.5 years, respectively. Exposure to perinatal CMD did not significantly affect child survival at 3.5 years, with results showing fully adjusted hazard ratio (HR) and 95% confidence interval (95% CI) of 1.85 (0.43, 7.88) for CMD in pregnancy only, 1.47 (0.14, 15.66) for CMD in postnatal period only and 0.41 (0.02, 7.38) for persistent CMD (both in pregnancy and postnatal). Only using soap less frequently than daily (HR 5.67, 95% CI 1.58–20.30) and episode of malaria in pregnancy (HR 5.02, 95% CI 2.15–11.72) were associated with child mortality in multivariable analysis.

Conclusions

Maternal health, health behaviours and family structure appear to be the most important factors affecting post‐neonatal child mortality in this Ethiopian birth cohort, with little evidence for an effect of maternal perinatal CMD.
Rust fungi and global change
Authors: Helfer Stephan
Published: October 2013

Rust fungi are important components of ecological communities and in ecosystem function. Their unique life strategies as biotrophic pathogens with complicated life cycles could make them vulnerable to global environmental change. While there are gaps in our knowledge, especially in natural plant–rust systems, this review of the exposure of rust fungi to global change parameters revealed that some host–rust relationships would decline under predicted environmental change scenarios, whereas others would either remain unchanged or become more prevalent. Notably, some graminicolous rusts are negatively affected by higher temperatures and increased concentrations of atmospheric CO2. An increase of atmospheric O3 appears to favour rust diseases on trees but not those on grasses. Combined effects of CO2 and O3 are intermediary. The most important global drivers for the geographical and host plant range expansion and prevalence of rusts, however, are global plant trade, host plant genetic homogenization and the regular occurrence of conducive environmental conditions, especially the availability of moisture. However, while rusts thrive in high‐humidity environments, they can also survive in desert habitats, and as a group their environmental tolerance is large, with no conclusive change in their overall prevalence predictable to date.
Temperature Fluctuations Inside the CANDU Reactor Moderator Test Facility (MTF)
Authors: Sarchami Araz , Ashgriz Nasser , Kwee Marc
Published: October 2013

Three dimensional numerical simulation is conducted on the CANDU Moderator Test Facility (MTF). Heat generation inside the tank is modeled through surface heating. Transient variations of the temperature and velocity distributions inside the tank are determined.

The results show that the flow and temperature distributions inside the moderator tank are three dimensional and no symmetry plane can be identified. A high temperature zone, located on the top left corner of the tank, is identified. The inlet jets are found to flow along the walls of the tank and impinge on each other at the top of the tank. This impingement point is located more towards the right side of the tank. The impingement of these two flow result in a secondary downward moving jet, which penetrates into the tube bundle. This secondary jet divides the tank into two sides. One side contains high temperature liquid and the other side contains low temperature liquid.

The temperature contours along the length of the tank have a saddle shape, with high temperatures towards the edges of the saddle. This is due to strong wall jet flows in the middle planes pushing the hotter fluid towards the end walls of the tank. Competition between the upward moving buoyancy driven flows and the downward moving momentum driven flows, results in the formation of circulation zones inside the tank. The numerical results for MTF indicate that the moderator tank operates in the buoyancy driven mode. Any small disturbances in the flow or temperature can make the system unstable and asymmetric. Once the system comes out of symmetry, it cannot go back to symmetry. This results in circulating buoyancy driven flow at one side and a momentum driven flow at the other side of tank.

Different types temperature fluctuations are noted inside the tank: (i) large amplitude temperature fluctuations are mainly at the boundaries between the hot and cold; (ii) low amplitude temperature fluctuations are mainly in the core of the tank with more uniform temperature distributions; (iii) high frequency fluctuations are in the regions with high velocities; and (iv) low frequency fluctuations are in the regions with lower fluid velocities.
A Procedure for Characterizing the Range of Input Uncertainty Parameters by the Use of the FFTBM
Authors: Kovtonyuk A. , Petruzzi A. , D’Auria F.
Published: October 2013

In the last years various methodologies were proposed to evaluate the uncertainty of Best Estimate (BE) code predictions. The most used method at the industrial level is based upon the selection of input uncertain parameters, on assigning related ranges of variations and Probability Distribution Functions (PDFs) and on performing a suitable number of code runs to get the combined effect of the variations on the results.

A procedure to characterize the variation ranges of the input uncertain parameters is proposed in the paper in place of the usual approach based (mostly) on engineering judgment. The procedure is based on the use of the Fast Fourier Transform Based Method (FFTBM), already part of the Uncertainty Method based on the Accuracy Extrapolation (UMAE) method and extensively used in several international frameworks.

The FFTBM has been originally developed to answer questions like “How long improvements should be added to the system thermal-hydraulic code model? How much simplifications can be introduced and how to conduct an objective comparison?”. The method, easy to understand, convenient to use and user independent, clearly indicates when simulation needs to be improved.

The procedure developed for characterizing the range of input uncertainty parameters involves the following main aspects:

a) One single input parameter shall not be ‘responsible’ for the entire error |exp-calc|, unless exceptional situations to be evaluated case by case;

b) Initial guess for Max and Min for variation ranges to be based on the usual (adopted) expertise;

c) More than one experiment can be used per each NPP and each scenario. Highly influential parameters are expected to be the same. The bounding ranges should be considered for the NPP uncertainty analysis;

d) A data base of suitable uncertainty input parameters can be created per each NPP and each transient scenario.
Recommended Practices for the Development of an Effective Steam Surface Condenser Maintenance Regime; Including Suggested Maintenance Solutions and Design Modifications That Can Improve Condenser Performance and Reliability
Authors: Nightingale Darren M.
Published: October 2013

A detailed & proper understanding of the main components that comprise a Steam Surface Condenser is absolutely essential when designing an effective maintenance regime. This Paper provides a breakdown for each of the main components, including typical ancillary items, which should be incorporated into visual inspections, and routine testing, when developing an effective maintenance regime for Steam Surface Condensers. Topics cover recommended inspection criteria for the main and ancillary components as well as proposed testing methods. Examples of known component failure modes, suggested repairs, replacements, modifications & upgrades are also included for reference. Implementation of an effective maintenance regime can help to ensure design performance is maintained. Often, it can even lead to improvements in unit availability and overall long term reliability; which in turn can result in tangible reductions in operating costs.
Test and Evaluation of a Filtering System for Retention of Fibres in a Coolant Flow After Loss-of-Coolant Accident
Authors: Gocht T. , Kästner W. , Kratzsch A. , Strasser M.
Published: October 2013

In case of an accident the safe heat removal from the reactor core with the installed emergency core cooling system (ECCS) is one of the main features in reactor safety. During a loss-of-coolant accident (LOCA) the release of insulation material fragments in the reactor containment can lead to malfunctions of ECCS. Therefore, the retention of particles by strainers or filtering systems in the ECCS is one of the major tasks.

The aim of the presented experimental investigations was the evaluation of a filtering system for the retention of fiber-shaped particles in a fluid flow. The filtering system consists of a filter case with a special lamellar filter unit. The tests were carried out at a test facility with filtering units of different mesh sizes. Insulation material (mineral rock wool) was fragmented to fiber-shaped particles. To simulate the distribution of particle concentration at real plants with large volumes the material was divided into single portions and introduced into the loop with a defined time interval. Material was transported to the filter by the fluid and agglomerated there. The assessment of functionality of the filtering system was made by differential pressure between inlet and outlet of the filtering system and by mass of penetrated particles. It can be concluded that for the tested filtering system no penetration of insulation particles occurred.
Evaluation of Concrete Structures Using Nondestructive Techniques
Authors: Limaye Hemant S.
Published: October 2013

To renew the expiring licenses of the nuclear power plants, the operators will need to evaluate major structural components for the age related deterioration. Assessment of the interior of the concrete structures can be made using the available nondestructive testing (NDT) methods. This paper presents a quick overview of the methods and describes how some of these methods were used for the two projects-one for the new construction and one for the existing project going through the modification/renovation.
Thermochemical Hydrogen Production IS process
Authors: Iwatsuki Jin , Kubo Shinji , Kasahara Seiji , Tanaka Nobuyuki , Noguchi Hiroki , Imai Yoshiyuki , Onuki Kaoru
Published: October 2013

The Japan Atomic Energy Agency (JAEA) is conducting research and development on nuclear hydrogen production using High Temperature Gas-cooled Reactor and thermochemical water-splitting Iodine-Sulfur (IS) process aiming to develop large-scale hydrogen production technology for “hydrogen energy system”. In this paper, the present status of R&D on IS process at JAEA is presented which focuses on examining integrity of such components as chemical reactors, separators, etc. Based on previous screening of materials of construction mainly from the viewpoint of corrosion resistance in the harsh process conditions of IS process, it was planned to fabricate the IS components and examine their integrity in the process environments. At present, among the components of IS process plant consisting of three chemical reaction sections, i.e., the Bunsen reaction section, the sulfuric acid decomposition section and the hydrogen iodide decomposition section, key components in the Bunsen reaction section was fabricated.
Probability Analysis of the Fuel Microsphere Distribution of Dispersion-Type Nuclear Fuel Plates
Authors: Gao Lijun , Pang Hua , Chen Bingde , Jiang Shengyao , Yu Jiyang , Xiao Zhong
Published: October 2013

The mechanism of microsphere interconnection through cracks, which is observed in post-irradiation examination of dispersion-type fuel plates for research reactor use and is responsible for blistering, is analyzed. The accumulation of fission gas with burnup and the resulting increase of gas pressure cause the metal matrix to crack and the fuel plate to blister. Based on the experimental observation, a small cylinder in the fuel mini-plate is chosen as the simulation volume. Assuming the diameter of fuel microspheres is identical and in normal distribution separately and the position of fuel microspheres is in uniform random distribution in the matrix, the distribution of fuel volume fraction in the cylinder of the mini-plate is simulated using Monte Carlo method. The analysis shows that the distribution of the fuel volume fraction is in good agreement with the normal distribution. Mini-plates with different fuel volume fractions are further calculated for comparison. The calculation for a full-size plate shows that as for the fuel volume fraction 0.21 and the inventory of reactor core the existence of cylinders with a fuel volume fraction which is susceptible to blistering turns out a possible threat to the fuel reliability. Probability analysis proves to be an effective technique for the quantitative characterization of dispersions.
Development of Long Rotating Blade Applied in the New Generation Nuclear Steam Turbine
Authors: Cheng Kai , Peng Zeying , Wang Gongyi , Wu Xiaoming , Yu Deqi
Published: October 2013

In order to meet the high economic requirement of the 3rd generation Pressurized Water Reactor (PWR) or Boiling Water Reactor (BWR) applied in currently developing nuclear power plants, a series of half-speed extra-long last stage rotating blades with 26 ∼ 30 m2 nominal exhaust annular area is proposed, which covers a blade-height range from 1600 mm to 1900 mm. It is well known that developing an extra long blade is a tough job involving some special coordinated sub-process. This paper is dedicated to describe the progress of creating a long rotating blade for a large scaled steam turbine involved in the 3rd generation nuclear power project. At first the strategy of how to determine the appropriate height for the last-stage-rotating-blade for the steam turbine is provided. Then the quasi-3D flow field quick design method for the last three stages in LP casing is discussed as well as the airfoil optimization method. Furthermore a sophisticated blade structure design and analyzing system for a long blade is introduced to obtain the detail dimension of the blade focusing on the good reliability during the service period. Thus, except for CAD and experiment process, the whole pre-design phase of the extra-long turbine blade is presented which is regarded as an assurance of the operation efficiency and reliability.
Generation of Response Spectra Compatible Artificial Acceleration Time Histories
Authors: Kähkönen Jukka , Varpasuo Pentti
Published: October 2013

A procedure to generate artificial acceleration time histories compatible with predefined target response spectrum is presented. The procedure is demonstrated with three examples.

It was found out that the generated artificial histories yield high quality response spectra for single-damping defined target spectra. A need for method that yields histories matching target spectra defined with multiple damping values was recognized.
Experimental Investigation on Rapid Evaporation of High-Pressure Liquids due to Depressurization
Authors: Zhang Qiaoling , Bi Qincheng , Nie Zesen , Liang Jun , Guo Yajun , Wang Chunming , Wang Yanping
Published: October 2013

This paper reports an experimental investigation of rapid evaporation process of high-pressure ethanol liquid during depressurization. The study focused on pressure and temperature transients with the influence of different initial conditions, and the shape variation was recorded via a high speed camera. During an experiment, the ethanol liquid was contained in a small round tube with a diameter 10mm in the test vessel, and a thermocouple was put within the fluid which was used to measure the fluid temperature during the depressurization. The predetermined pressure was provided by the high-pressure nitrogen gas, and the process of quick depressurization was started by opening the magnetic valve, which was connected with the test vessel. The transitions of the pressure and the fluid temperature were recorded by the NI data collection system. According to the experimental results, during the fast pressure drop, with the same initial temperature and other test conditions, the higher the initial pressure is, the faster the liquid temperature decreases, and the lower the minimum temperature reaches. In addition, the effect of initial fluid conditions, initial environmental pressure on temperature transition and so on are summed up and are experimentally analyzed on the fluid temperature change under the same test equipment. Also, the variation characteristics of kerosene fluid were compared with ethanol liquid under the same experiment conditions.
MARS-KS Calculations for ATLAS 6-Inch Cold Leg Break (SBLOCA) Test
Authors: Kang Dong-Gu , Kim Joo-Sung , Ahn Seung-Hoon
Published: October 2013

An integral effect test on the SBLOCA (Small-Break Loss of Coolant Accident) aiming at 6-inch cold leg bottom break, SB-CL-09, was conducted with the ATLAS on November, 13, 2009 by KAERI. In this study, the calculations using MARS-KS V1.2 code were conducted for 6-inch cold leg break test of ATLAS (SB-CL-09) to assess MARS-KS code capability to simulate the transient thermal-hydraulic behavior for SBLOCA. The steady state was determined by conducting a null transient calculation and the errors between the calculated and measured values are acceptable for almost primary/secondary system parameters. The sequence of events except the location of loop seal clearing (LSC) and SIT injection time was predicted relatively well. The predicted pressurizer pressure agrees relatively well with the experimental data and the predicted break flow and mass are in good agreement with experiment. In MARS-KS calculation, the decrease of core collapsed water level is predicted well in blowdown phase, but just before LSC, water level is higher than experiment. However, the sudden decrease and increase of water level at the LSC are predicted qualitatively. After LSC, there is another water level dip at SIT injection time which is not in experiment. It is considered that this phenomenon is caused by rapid depressurization of downcomer due to significant condensation rate of vapor in downcomer when SIT water flows in it. For the downcomer water level, before the SIT injection time, water level is predicted well, however, it is significantly over-predicted at SIT injection time after SIT water flows in downcomer. Predicted cladding temperature generally agrees well with the experiment, while there is peak at SIT injection time in calculation which is not in experiment. The loop seals of 1A, 2B intermediate leg are cleared around 400 seconds in experiment, while only that of 1A is cleared in MARS-KS calculation at the same time. In conclusions, MARS-KS code has good capabilities to simulate cold leg break SBLOCA, however, there are some discrepancies in quantitatively predicting the steam generator secondary pressure, core collapsed liquid level, downcomer liquid level, and so on. Therefore, MARS-KS code including interfacial condensation model needs to be improved to predict more accurate results.
Transient Critical Heat Fluxes of Subcooled Water Flow Boiling in a Short SUS304-Tube With Twisted-Tape Insert
Authors: Hata Koichi , Shirai Yasuyuki , Masuzaki Suguru
Published: October 2013

The transient critical heat fluxes (transient CHFs) in a short SUS304-tube with twisted-tape insert are systematically measured for mass velocities (G = 3997.79 to 13419.8 kg/m2s), inlet liquid temperatures (Tin = 293.55 to 300.85 K), outlet pressures (Pout = 825.19 to 860.95 kPa) and exponentially increasing heat inputs (Q = Q0exp(t/τ), τ = 26.85 ms to 8.42 s) by the experimental water loop comprised of a multistage canned-type circulation pump controlled by an inverter. The SUS304 test tube of inner diameter (d = 6 mm), heated length (L = 59.4 mm), effective length (Leff = 49.4 mm), L/d (= 9.9), Leff/d (= 8.23) and wall thickness (δ = 0.5 mm) with average surface roughness (Ra = 3.89 μm) is used in this work. The SUS304 twisted-tape with width (w = 5.6 mm), thickness (δT = 0.6 mm), total length (l = 372 mm) and twist ratio, y [= H/d = (pitch of 180° rotation)/d], of 3.37 is used. The transient CHFs for a short SUS304-tube with twisted-tape insert are compared with authors’ steady-state CHF data for a short SUS304-tube with various twisted-tape inserts, their transient CHF data for the empty SUS304-tube and the values calculated by authors’ steady-state CHF correlations for the test tubes with various twisted-tape inserts and their transient CHF correlations for the empty test tubes. The influences of twisted-tape insert, heating rate and swirl velocity on the transient CHF are investigated into details and the widely and precisely predictable correlations of the transient CHF for the test tube with twisted-tape insert are given based on the experimental data. The correlations can describe the transient CHFs for a short SUS304-tube with twisted-tape of y = 3.37 obtained in this work within −27 to 7.9 % difference.
R&D of Validity Evaluation System for Seismic Simulation of Entire Nuclear Plant
Authors: Suzuki Yoshio , Miyamura Hiroko Nakamura , Nakajima Norihiro
Published: October 2013

Our goal is to evaluate validity of numerical simulation results in the nuclear field in order to estimate real behavior of nuclear plants and thus to contribute their security and safety. Recently, it becomes possible to execute a full-scale numerical simulation under a real condition, such as a seismic behavior of entire nuclear plant. To estimate real behavior accurately by such simulations, it is indispensable to evaluate validity of simulation results because numerical simulations include various uncertainties such as “uncertainty due to randomness” and “uncertainty due to lack of knowledge”. As one of approaches to evaluate validity of simulation results, we introduce “the degree of certainty” of simulations to real behavior. Here, to get a more accurate degree of certainty, we try to confirm the degree of influence about unevenness of uncertainty and to reduce uncertainty due to lack of knowledge. For this, we research and develop a validity evaluation system composed of three tools. One is a tool able to introduce the degree of certainty from various uncertainties to put together various uncertainties. Another is a tool able to analyze the sensitivity of each uncertainty to whole uncertainty. Moreover, we research a tool able to analyze factors of various uncertainties. We have applied them to our seismic simulation system which enables to execute the assembly structure analysis of an entire nuclear plant and confirmed that their functions are applicable to the simulation.
Mitigation of PWR In-Containment Iodine Source Term Under LOCA
Authors: Mehboob Khurram , Cao Xinrong , Ali Majid , Khan Rehan
Published: October 2013

Since, containment integrity is the main issue under accidental conditions. Radiological consequences of LWR under accident have the grievous impact on the reactor building and its surrounding environment. Iodine is one of the most hazardous fission product releases in the serious accidents. So in this paper, the iodine source term has been evaluated for two-loop PWR under severe accident initiated due to LOCA. The TMI-2 reactor is considered as the reference reactor. The modeling and simulations are carried out by developing a MATLAB base program that uses the post-accident conditions and core inventory as input. The containment response, in order to mitigate the environmental and in-containment iodine source term is studied in normal, emergency, and isolation states of containment. The In-containment iodine source term is calculated with, and without the operation of engineering safety features (ESFs). The mitigation is determined by the activation of ESF. The environmental iodine source term is calculated as the function of containment response. The iodine dependency on the containment retention factor is also studied in all said states of containment. Results indicate the weak sensitivity of Iodine with activation of ESF towards exhaust rate values, under ESFs Operation.
On the Use of Support Vector Regression Technique for the Analysis of Rod Ejection Accidents
Authors: Jiang Botao , Liu Yang , Zhao Fuyu
Published: October 2013

The rod ejection accident (REA) is the design-basis reactivity initiated event and an important aspect for a pressurized water reactor (PWR). The consequence of REA is that it introduces a large positive reactivity insertion in a core, which leads to a fast large power excursion and other parameters changing. Thus, it is important to understand the uncertainty in the parameters of reactor core when REA happens. This paper applies support vector regression (SVR) to analyze accident scenarios with control rod ejection. SVR is an approach based on machine learning and soft computing. SVR, by definition, is an application of support vector machine (SVM) to nonlinear regression problem. Furthermore, the objective of this paper is to train SVR model to identify both safe and potentially unsafe power plant conditions based on real time plant data. The data is obtained from computer generated accident scenarios and is divided into two datasets, training datasets and test datasets. The training dataset are used to train the SVR model and the test dataset are used to test the validation of this model. And then the results obtained by SVR model are compared with that of artificial neural network (ANN) model. The comparison results show that SVR model has superior performance over ANN model and agree well with the general understanding. Because the proposed methodology achieve accurate results, it is likely to be suitable for other data processing of nuclear engineering.
Experimental Investigation on the Effect of Bubble Behavior on Flow Boiling Pressure Drop in Narrow Channel
Authors: Chen Deqi , Song Ren , Pan Liang-ming
Published: October 2013

Bubble behavior in narrow channel can be quite different with that in conventional channel. When the bubble reaches a size which is comparable with the channel dimension, the bubble is confined by the channel wall. This influences the bubble evolution significantly in the narrow channel. Then the characteristics of pressure drop in the narrow channel is affected significantly. In order to investigate the effect of bubble behavior on flow boiling pressure drop, a visual study was carried out with a high speed camera (5,000 frame per second was used) to record the bubble behavior. It is found that the OSV (Onset of Significant Vapor) emerges much earlier in narrow channel when comparing with that in conventional channel. A revised correlation for prediction of the real void fraction is proposed based on the experimental investigation. It is also found that the bubble behavior affects the pressure drop in narrow channel significantly, and the channel will be blocked easily when the confined vapor cluster appears. The pressure drop, however, dose not increase linearly with increasing void fraction, and the minimum pressure drop occurs with 60% void fraction. With increasing void fraction, the bubble behavior is more intense and turbulent, which induces more severe fluctuation in pressure drop.
Single Bubble Growth at Different Gravity and the Effects of Microgravity on Marangoni Convection
Authors: Yang Yan , Pan Liang-ming , Xue Long-chang
Published: October 2013

In this paper, based on the previous experiment and the VOF (Volume of Fluid) multiphase model, the growth characteristics of a single bubble was numerically investigated in a rectangular pool boiling channel (10 mm × 10 mm × 25 mm) under micro-gravity. The transportation of mass and energy during the phase change was established by adding source term to the mass and energy equations with User Defined Function (UDF). The results showed that under microgravity, the streamline and the temperature field distribution around the bubble were significantly changed compared with the normal gravity, and the flow field and the temperature are no longer a symmetrical distribution. The bubble between microgravity and normal gravity was different from the detachment, and it does not departure from the heating wall directly under the microgravity conditions because of surface tension. But the surface tension gradient caused Marangoni effects are more significant at the smaller microgravity. The bubble growth is more complicated under the conditions of microgravity, and it is connected with the degree of the microgravity: smaller microgravity will result higher bubble growth rate. Moreover, the bubble diameter was changed more fantasticality, under microgravity and the heat transfer coefficient fluctuated more heavily with the increasing of microgravity.
Investigation on Characteristics of Experiment About Single-Beam Measurements of Supercritical Fluid
Authors: Zhao Yu , Bi Qincheng , Hu Richa , Li Huixiong
Published: October 2013

An experiment has recently been completed at Xi’an Jiaotong University (XJTU) to obtain thermo-physical characteristics of supercritical pressure water at supercritical pressures with upward flow of water inside a vertically-upward bare tube. The thermo-physical characteristics of supercritical pressure water were investigated experimentally by means of a non-intrusive measurement method, using a single-beam gamma densitometer generated from the radioactive sources (Cs-137). The purpose of this experiment is to investigate accurately the changes drastic thermo-physical characteristics process of supercritical pressure water at pseudocritical point, comparing and analyzing in-depth the experiment results at different pressures and mass fluxes. Several factors influencing the performance of the gamma densitometer are examined, including the distance between the source and the detector, the distance between the source and the test section, the measuring time, the intensity of source, and the ambient temperature.
Two-Group Relative Velocity in Boiling Two-Phase Flow
Authors: Brooks Caleb S. , Ozar Basar , Hibiki Takashi , Ishii Mamoru
Published: October 2013

In an effort to improve the prediction of void fraction and heat transfer characteristics in two-phase systems, the two-group interfacial area transport equation has been developed for use with the two-group two-fluid model. In the one-dimensional formulation, a closure relation is required for the group-1 and group-2 area-average local relative velocity. Furthermore, in the case of the modified two-fluid model with the gas-mixture momentum equation, the group-1 and group-2 void weighted gas velocities must be calculated with additional closure relations. Therefore, the drift-flux general expression is extended to two bubble groups in order to describe the group-1 and group-2 void weighted gas velocities and area-averaged local relative velocities. Correlations for group-1 and group-2 distribution parameters and drift velocities are proposed and evaluated with a dataset containing 57 boiling conditions taken in an internally heated annulus. The proposed distribution parameters show an agreement within +/−5%. The overall estimation of group-1 and group-2 void weighted gas velocities calculated with the newly proposed two-group drift-flux general expression shows an agreement within +/−15% of the measured value.
Dynamic Response Analysis of Control Rod Drive Mechanism Under the Stepping Impact Force for Nuclear Power Plants
Authors: Shen Xiaoyao , Xie Yongcheng
Published: October 2013

The control rod drive mechanism (CRDM) is an important safety-related component in the nuclear power plant (NPP). When CRDM steps upward or downward, the pressure-containing housing of CRDM is shocked axially by an impact force from the engagement of the magnetic pole and the armature. To ensure the structural integrity of the primary coolant loop and the functionality of CRDM, dynamic response of CRDM under the impact force should be studied. In this manuscript, the commercial finite element software ANSYS is chosen to analyze the nonlinear impact problem. A nonlinear model is setup in ANSYS, including main CRDM parts such as the control rod, poles and armatures, as well as nonlinear gaps. The transient analysis method is adopted to calculate CRDM dynamic response when it steps upward. The impact loads and displacements at typical CRDM locations are successfully obtained, which are essential for design and stress analysis of CRDM.
A Large Eddy Simulation of the Bubbly Flow in Vertical Tube
Authors: Zhang Peng , Hong Xu
Published: October 2013

This paper simulates the dispersed bubbly flow in a vertical tube with two different turbulence models based on Eulerian two-fluid frameworks. Both the RANS (Reynolds Averaged N-S equation) approach and LES (Large Eddy Simulation) approach can get results agreed with experiment well. The “wall peak” bubble distribution is captured. Compare with RANS with SST (Shear Stress Transport) turbulence model, the LES with WALE (Wall-Adapted Local Eddy-viscosity) sub-grid model can give transient and detail information of the flow field, and it shows better agreement.