bluuebunny/crossref_metadata_2025 huggingface dataset:
Dantrolene Suppresses Ventricular Ectopy and Arrhythmogenicity with Acute Myocardial Infarction in a Langendorff‐Perfused Pacing‐Induced Heart Failure Rabbit Model
Authors: CHOU CHUNG‐CHUAN , WEN MING‐SHIEN , LEE HUI‐LING , CHANG PO‐CHENG , WO HUNG‐TA , YEH SAN‐JOU , WU DELON
Published: November 2013

Dantrolene in Failing Hearts with AMI

Introduction

Dantrolene prevents arrhythmogenic Ca2+ release during heart failure (HF). However, direct evidence to support its antiarrhythmic effects in failing hearts with acute myocardial infarction (AMI) is lacking.

Methods and Results

HF was induced by right ventricular pacing (312 beats/min, 4 weeks) in 19 rabbits. AMI was induced by coronary artery ligation in rabbits surviving chronic pacing (n = 17). The hearts were quickly excised and Langendorff‐perfused for simultaneous membrane potential and intracellular Ca2+ (Cai) optical mapping when ventricular fibrillation (VF) occurred or 4 hours after AMI. The VF inducibility was defined as the ability to provoke sustained VF (>2 minutes) by pacing. Dantrolene (10 μM) was administered after baseline studies. Spontaneous VF occurred in 5 rabbits (SVF group). The ventricular premature beat (VPB) burden was significantly higher in the SVF group than the non‐SVF group (P < 0.05). Dantrolene suppressed VPB burden (P = 0.03) and prolonged action potential duration (APD; P < 0.05) to reduce VF inducibility (P < 0.05). However, dantrolene shortened immediate postshock APD50 even if VF storm was suppressed.

Conclusion

In failing hearts with AMI, VPB burden plays a pivotal role in SVF occurrence. Dantrolene suppresses VPBs and/or prolongs repolarization to inhibit spontaneous VF and reduce VF inducibility.
Mobitz Type II Second‐Degree Atrioventricular Block with Narrow QRS and Junctional Extrasystoles: What is the Mechanism?
Authors: JIMÉNEZ‐DÍAZ JAVIER , GONZÁLEZ‐FERRER JUAN J. , HEREDIA GIOVANNA U. , MORENO‐PLANAS JAVIER
Published: November 2013

Arrhythmia Rounds

A 74‐year‐old man underwent an electrophysiological study because of Mobitz type II second‐degree atrioventricular (AV) block with narrow QRS and frequent junctional extrasystoles. During the study, there were very frequent single His bundle depolarizations with multiple coupling intervals that reproduce the ECG findings. In this case, some His bundle extrasystoles result in retrograde concealed conduction and prolonged local refractoriness in the AV node that manifest as block of the next atrial impulse.
RebalancingEUInterest Representation? Associative Democracy andEUFunding of Civil Society Organizations
Authors: Sanchez Salgado Rosa
Published: November 2013

EuropeanUnion (EU) funding of civil society organizations (CSOs) is a substantial and important part ofEUgovernance, but study of such funding is scarce and theoretically underdeveloped. To fill this gap, this article analyzes the main features ofEUfunding ofCSOsand its effects on theEUsystem of interest representation, drawing on policy documents and theEUregister of interest representatives. The resulting analysis shows thatEUfunding ofCSOsin the social sector tends to reflect many of the characteristics of the model of associative democracy.European funds are being directed to groups that voice the concerns of excluded groups and, in this way, address imbalances inEUinterest representation. TheEUalso promotes certain healthy features amongCSOs, since it restricts access to funding opportunities to interest groups fulfilling key normative criteria. Hence, theEUhelps sustain, but does not significantly constrain, the development ofEuropeanCSOs.
Of Gay Rights and Christmas Ornaments: The Political History of Sexual Orientation Non‐discrimination in the Treaty of Amsterdam
Authors: Mos Martijn
Published: November 2013

This article asks why sexual orientation was included in the anti‐discrimination clause of the Treaty of Amsterdam (Article 13) in the absence of active support within the Council of Ministers and even though few Member States had established it as protected ground prior to the intergovernmental conference. A detailed historical analysis reveals how the European Parliament (EP) gradually developed into the hub of a transnational advocacy network that promoted gay rights to the European Commission and the Council. The dynamics of the intergovernmental conference enabled the EP to introduce sexual orientation into the treaty‐making process, while the use of naming‐and‐shaming tactics vis‐à‐vis the Dutch Presidency secured the ground's final inclusion. This political history has theoretical implications since it presents a challenge to extant liberal intergovernmentalist and institutionalist analyses of the Amsterdam Treaty and suggests that the EP should be afforded more attention by neofunctionalist scholars.
Comparing Constitutional Change in European Union Member States: In Search of a Theory
Authors: Karlsson Christer
Published: November 2013

This article explores the under‐researched issue of how constitutional change is brought about in modern democracies. Despite the fundamental importance of constitutions, we know surprisingly little about whether constitutional change is achieved by changing the explicit wording of the constitutional document, or by way of changing the meaning of the constitution while leaving the constitutional text unaltered. Which is the more common method and what variations in the use of these different methods are there in democratic political systems? This study systematically compares the use of explicit and implicit constitutional change in European Union (EU) Member States. The results show that implicit constitutional change is the more frequently used method, but also reveal substantial differences between EU countries. The article closes by discussing the road towards a theory of constitutional change. It does so by presenting five testable propositions that could lay the foundation for a theory of constitutional change.
Hypothermia induced by adenosine 5′‐monophosphate attenuates injury in an L‐arginine‐induced acute pancreatitis rat model
Authors: Wang Yunlong , Guo Weiting , Li Yuan , Pan Xinting , Lv Wenshan , Cui Lingling , Li Changgui , Wang Yangang , Yan Shengli , Zhang Jidong , Liu Bin
Published: November 2013

Background and Aim

This study sought to investigate the effects of hypothermia induced by adenosine 5′‐monophosphate (5′‐AMP) on L‐arginine (L‐Arg)‐induced acute pancreatitis in rats.

Methods

The rats were divided into four groups: the control group, the acute pancreatitis group, the 5′‐AMP pretreatment group, and the 5′‐AMP posttreatment group. Rats in all groups, except for the control group, received two injections of 2.5 g/kg body weight (intraperitoneally) L‐Arg, with an interval of 1 h between the injections. Subsequently, the rats were observed to assess whether hypothermia induced by 5′‐AMP could effectively inhibit inflammation associated with L‐Arg‐induced acute pancreatitis in rats.

Results

Hypothermia induced by 5′‐AMP produced protective effects in our acute pancreatitis model. These effects exhibited the following manifestations: (i) a significant reduction in rat mortality rates; (ii) a significant decrease in the occurrence of pancreatic edema; (iii) significant reductions in serum amylase (P < 0.001), interleukin‐6 (P < 0.001), interleukin‐1β (P < 0.001) and tumor necrosis factor‐α (P < 0.001); (iv) the significant inhibition of nuclear factor‐κB (NF‐κB) activation in rats that were pre‐ and posttreated with 5′‐AMP compared with rats that were only injected with L‐Arg; and (v) significant decreases in the occurrence of pancreatic interstitial edema, inflammatory cell infiltration, hemorrhage, and acinar cell necrosis.

Conclusions

Hypothermia induced by 5′‐AMP could inhibit the acute inflammatory reaction and NF‐κB activation associated with acute pancreatitis.
Quantification of hepatic steatosis: A comparison of the accuracy among multiple magnetic resonance techniques
Authors: Wu Chih‐Horng , Ho Ming‐Chih , Jeng Yung‐Ming , Hsu Chao‐Yu , Liang Po‐Chin , Hu Rey‐Heng , Lai Hong‐Shiee , Shih Tiffany Ting‐Fang
Published: November 2013

Background and Aim

Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) are important diagnostic tools for the non‐invasive assessment of hepatic steatosis (HS). This study was conducted to compare different magnetic resonance (MR) techniques and correlate the MR findings with histological and intracellular lipid density findings.

Methods

In this institutional review board‐approved, Health Insurance Portability and Accountability Act‐compliant prospective study, 60 patients scheduled for liver resection were included in this study. Fat fraction in the non‐tumorous liver parenchyma was estimated using double‐echo MRI, triple‐echo MRI (TE‐MRI), and MRS. HS was defined by the histologic steatosis percentage (HSP), and intrahepatocellular triglyceride density (IHTGD) of the surgical specimen used as the reference standard. Imaging quantification results were evaluated using Pearson's correlation. Lin's concordance coefficient and Bland–Altman 95% limits of agreement were used to evaluate the concordance of IHTGDs estimated by the three MR techniques. The diagnostic performance was compared using receiver operating characteristic curve analysis.

Results

HS assessed by TE‐MRI and MRS had a stronger relationship with HS assessed by HSP and IHTGD. The TE‐MRI method had the highest concordance correlation coefficients (ρ = 0.881) and percentage (95%, 57/60) within the Bland–Altman 95% limits of agreement. Receiver operating characteristic curve analysis for diagnosing > 5% HSP showed significantly larger area under the curve (0.9783) for TE‐MRI than for double‐echo MRI (0.8773, P = 0.0121).

Conclusions

Among the three MR techniques, TE‐MRI and MRS may be the preferred techniques for non‐invasive assessment of HS.
Effectiveness of Tadalafil 5 mg Once Daily in the Treatment of Men with Lower Urinary Tract Symptoms Suggestive to Benign Prostatic Hyperplasia With or Without Erectile Dysfunction: Results from Naturalistic Observational TadaLutsEd Study
Authors: Bechara Amado , Casabe Adolfo , Rodriguez Baigorri Gustavo , Cobreros Christian
Published: November 2013

Introduction

Naturalistic clinical trials provide data on the effectiveness of drugs in nonexperimental and everyday situations and are extremely helpful for decision-making purposes and for confirming experimental findings in clinical trials. No data have been published from naturalistic studies performed in patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia (LUTS/BPH) with or without erectile dysfunction (ED) and treated with phosphodiesterase type 5 inhibitors.

Aim

The aim of this study (TadaLutsEd Study) was to assess, in the context of medical practice, the effectiveness of tadalafil 5 mg once daily in patients with LUTS/BPH with or without erectile dysfunction.

Methods

The study was a 6-week uncontrolled, prospective, open-label, multicentric, observational study.

The patient population involved sexually active males aged ≥50 years, diagnosed with LUTS/BPH with or without concomitant ED, and treated with tadalafil 5 mg daily in accordance with standard urological practice.

Main Outcome Measures

Effectiveness was assessed through the self-administered International Prostate Symptom Score (IPSS) questionnaire; quality of life was evaluated through the IPSS quality of life section (IPSS-QoL). The patients were also evaluated with the International Index of Erectile Function (IIEF-5). Adverse events were recorded. Statistical analyses using paired data samples was applied (Wilcoxon signed-ranks test).

Results

Sixty-two patients (mean age 62.2 years) completed the treatment, of whom 85.5% showed improvement in their urinary symptoms. Pre- and post-treatment differences in the IPSS, IPSS-QoL, and IIEF-5 scores were statistically significant at 4.4, 1, and 5.4 points, respectively (P < 0.0001). Tadalafil was well tolerated, and adverse events were mild, with a discontinuation rate of 1.6%.

Conclusion

According to study results, the use of tadalafil 5 mg once daily in a nonselected patient population with LUTS/BPH with or without ED led to improvements in terms of symptoms and quality of life and exhibited a safety profile similar to that obtained in controlled tadalafil clinical trials.
A Functional Magnetic Resonance Imaging Study of Foreign‐Language Vocabulary Learning Enhanced by Phonological Rehearsal: The Role of the Right Cerebellum and Left Fusiform Gyrus
Authors: Makita Kai , Yamazaki Mika , Tanabe Hiroki C. , Koike Takahiko , Kochiyama Takanori , Yokokawa Hirokazu , Yoshida Haruyo , Sadato Norihiro
Published: November 2013

Psychological research suggests that foreign‐language vocabulary acquisition recruits the phonological loop for verbal working memory. To depict the neural underpinnings and shed light on the process of foreign language learning, we conducted functional magnetic resonance imaging of Japanese participants without previous exposure to the Uzbek language using learning of novel Uzbek words. During encoding, spoken Uzbek words and corresponding visual objects were shown, and subjects either overtly repeated the words (phonological rehearsal) or overtly rehearsed numbers (phonological suppression). Phonological rehearsal improved the encoding performance. A learning‐related decrease in rehearsal‐specific activation was found in the left fusiform gyrus, right inferior temporal gyrus, and right cerebellum. Recollection of the phonologically rehearsed words activated the right cerebellum and left fusiform gyrus more prominently than recollection of the phonologically suppressed words in a performance‐dependent manner. The phonological loop might provide the temporal and fragile registration of the articulatory pattern that is converted into a more durable form in the right cerebellum, which is in turn integrated with the object information in the fusiform gyrus.
Loss of endoplasmic reticulum calcium pump expression in choroid plexus tumours
Authors: Ait‐Ghezali Lamia , Arbabian Atousa , Jeibmann Astrid , Hasselblatt Martin , Hallaert Giorgio G. , Van den Broecke Caroline , Gray Françoise , Brouland Jean‐Philippe , Varin‐Blank Nadine , Papp Bela
Published: November 2013

Aims

Sarco/Endoplasmic Reticulum Calcium ATPase‐type calcium pumps (SERCA enzymes) control cell activation by sequestering calcium ions from the cytosol into the endoplasmic reticulum. Although endoplasmic reticulum calcium signalling plays an important role in the regulation of choroid plexus epithelial function, SERCA expression in the choroid plexus has not been investigated so far.

Methods

In this work we investigated the expression of the SERCA3‐type calcium pump in choroid plexus epithelial cells grown in vitro, and in normal and hyperplastic choroid plexus tissue, in choroid plexus papillomas displaying various degrees of atypia, and in choroid plexus carcinoma by immunohistochemistry in situ.

Results

Whereas normal choroid plexus epithelial cells express SERCA3 abundantly, SERCA3 expression is strongly decreased in papillomas, and is absent in choroid plexus carcinoma, while expression in hyperplastic epithelium is high, similarly to normal epithelium. SERCA3 expression was detected also in normal primary choroid plexus epithelial cells grown in vitro, and expression was markedly enhanced by short‐chain fatty acid‐type cell differentiation inducing agents, including valproate.

Conclusion

These observations show that SERCA3 is a new phenotypic marker of normal choroid plexus epithelial differentiation, and that SERCA3 constitutes an early tumour marker ‘by loss of expression’ in the choroid plexus that may be useful to distinguish hyperplastic processes from papillomas. Endoplasmic reticulum calcium homeostasis becomes anomalous, due to loss of SERCA3 expression, already in benign neoplastic lesions of the choroid plexus epithelium.
Diaper Dermatitis: Etiology, Manifestations, Prevention, and Management
Authors: Stamatas Georgios N. , Tierney Neena K.
Published: November 2013

Pediatricians and parents report diaper dermatitis (DD) to be one of the most common skin diseases that affects almost every child at some point during the early months and years of life. Diapered skin is exposed to friction and excessive hydration, has a higher pH than nondiapered skin, and is repeatedly soiled with feces that contains enzymes with high irritation potential for the skin. The combination of these factors frequently results in skin damage, leading to visible erythematous lesions that can be irritating and painful to the child. Behavioral changes such as increased crying and agitation and changes in eating and sleeping patterns indicate emotional distress. Appropriate skin care can help to prevent the occurrence of DD and to speed up the healing of affected skin. This includes frequent diaper changes and aeration, gentle cleansing, and the use of a barrier cream. Mild to moderate cases usually resolve after a few days of following this routine, but the use of harsh cleaning products can exacerbate DD.
Langerhans Cell Disease of the Eyelids Masquerading as Blepharochalasis
Authors: Gupta Ruchi , Gautam Ram Krishan , Dewan Taru , Bhardwaj Minakshi
Published: November 2013

Langerhans cell disease (LCD) occurring as an isolated tumor of the eyelids has been described infrequently. Moreover, none of the reported cases had associated systemic involvement. We present an unusual case of LCD of the eyelids masquerading as blepharochalasis with central diabetes insipidus (CDI).
Pediatric Cutaneous Lupus Erythematosus Treated with Pulsed Dye Laser
Authors: Yélamos Oriol , Roé Esther , Baselga Eulàlia , Puig Lluís
Published: November 2013

Pulsed dye laser (PDL) has been used in adults to treat refractory cutaneous lupus erythematosus (CLE). We report the first case of CLE in a child successfully treated with PDL.
Combined effects of resource heterogeneity and simulated herbivory on plasticity of clonal integration in a rhizomatous perennial herb
Authors: Gao Y. , Wang D. , Xing F. , Liu J. , Wang L.
Published: November 2013

Previous lines of investigation assuming potential advantage of clonal integration generally have neglected its plasticity in complex heterogeneous environments. Clonal plants adaptively respond to abiotic heterogeneity (patchy resource distribution) and herbivory‐induced heterogeneity (within‐clone heterogeneity in ramet performance), but to date little is known about how resource heterogeneity and simulated herbivory jointly affect the overall performance of clones. Partial damage within a clone caused by herbivory might create herbivory‐induced heterogeneity in a resource‐homogeneous environment, and might also decrease or increase the extent of heterogeneity under resource‐heterogeneous conditions. We conducted a greenhouse experiment in which target‐ramets of Leymus chinensis segments within homogeneous or heterogeneous nutrient treatments were subject to clipping (0% or 75% shoot removal). In homogeneous environments with high (9:9) nutrient availability, ramet biomass of L. chinensis with intact or severed rhizomes is 0.70 or 0.69 g. Conversely, target‐ramet biomass with intact rhizomes is obviously lower than that of the severed target‐ramets in the homogeneous environments with medium (5:5) and low (1:1) nutrient availability. High resource availability and the presence of herbivory can alleviate negative effects of rhizome connection under homogeneous conditions, by providing copious resource or creating herbivory‐induced heterogeneity respectively. Herbivory tolerance of clonal fragments with connected rhizomes was higher than that of fragments with severed rhizomes under heterogeneous conditions. These findings confirmed the unconditional advantage of clonal integration on reproduction under the combined influence of resource heterogeneity and simulated herbivory. Moreover, our results made clear the synergistically interactive effects of resource heterogeneity and simulated herbivory on costs and benefits of clonal integration. This will undoubtedly advance our understanding on the plasticity of clonal integration under complex environmental conditions.
Prediction of correlates of daily physical activity in Spanish children aged 8–9 years
Authors: Saavedra J. M. , Escalante Y. , Domínguez A. M. , García‐Hermoso A. , Hernández‐Mocholí M. A.
Published: November 2013

The aims of the study were (a) to examine the associations between the daily physical activity (PA) of 8‐ to 9‐year‐old children and their parents, and (b) to examine what effect the child's daily PA has on its cardiorespiratory fitness (CRF), body mass index (BMI), and health‐related quality of life (HRQoL). The sample consisted of 1021 persons [351 children (8.73 ± 0.69 years in age) and 670 parents]. Pedometers were used to evaluate PA in parents and their children over the course of 4 days (Thursday–Sunday), with the instructions on how to wear the pedometers for 24 h a day. Also evaluated were height, weight, BMI, CRF (via the maximal multistage 20‐m shuttle run test), and HRQoL (via the EQ‐5D‐Y questionnaire). Associations between these variables were studied using path model techniques. The father's PA predicts his child's daily PA. This in turn predicts the child's lower BMI, CRF, and perceived quality of life. The findings suggest that the role model of a physically active father positively influences the child's PA habits, and hence that the family environment can have an important part to play in promoting health.
In vitro properties of platelets stored in a small container for pediatric transfusion
Authors: Tynngård Nahreen , Trinks Marie , Berlin Gösta
Published: November 2013

Background

The quality of a platelet (PLT) concentrate (PC) is affected by the number of PLTs in relation to the size and gas permeability of the container. This study evaluates the in vitro function, including hemostatic properties (clot formation and elasticity), of PLTs stored in a container of standard or small size.

Study Design and Methods

PCs with 30% plasma and 70% PLT additive solution were prepared from buffy coats. Two PCs were pooled and divided into the following containers: 1 unit and ½ a unit into a 1.8‐L container (reference container) and ½ a unit into a 0.45‐L container (test container). In a second set of experiments ¼ of a unit was stored in the reference and test containers. Swirling, PLT count, blood gases, metabolic variables, PLT activation markers, hypotonic shock response (HSR), and coagulation by free oscillation rheometry were analyzed during 7 days of storage.

Results

Swirling was well preserved and pH was acceptable (6.4‐7.4) during storage of PLTs in both containers. Glycolysis and PLT activation were higher when storing ½ and ¼ of a unit in the reference container and storage of ¼ of a unit in the reference container resulted in the largest decrease in HSR. The clotting time was similar whereas the clot elasticity was slightly lower for PLTs when stored as ½ and ¼ of a unit in the reference container.

Conclusion

Storage of a low number of PLTs benefits by storage in a small container in terms of better maintained in vitro properties.
When Labor and Migration Dis‐Place Film: Sketch of an Idea
Authors: Bâ Saër Maty
Published: November 2013

This essay proposes a sketch of an Idea for how to investigate connections between Film Studies, film as a medium, labor, and migration. It begins by making three interconnected provocations: (1) histories of Film Studies, and of film as a medium, should display constant engagement with labor, work, labor movements, class, and justice; (2) in our current world of globalized capital and culture, film embodies the unending processes of adjustment intrinsic to labor, class, and migration; (3) nowadays, images cross borders and boundaries easily, and thus call for a sustained critical look at how the medium of film represents matters of labor, class, and migration. Building on these provocations, the essay argues that labor, class, and migration might be, collectively, what Alain Badiou calls “a new sun” and “a new mental country” that Film Studies must desperately find lest, perhaps, Film Studies perishes. In so doing, the essay explores three interrelated questions: firstly, ways in which belief (in specific processes) can be described, prior to being applicable to anything; secondly, in a search for the real, in a quest for what is real, how an Idea of science is mobilized; and finally, ways in which “Labor”/“Migrant Labor” and “Film” can be perceived today.
Class, Ethnicity, and Immigration in Sweden: Two Films, Two Strategies
Authors: Lindvall Daniel
Published: November 2013

Against a background of growing inequality, “class” as a subject has made its comeback in Swedish arts and public debate generally. This has resulted in some very strong cinematic depictions of the upper social classes. But when it comes to the working class, films have tended to demonize or mock, to focus on criminality and drug abuse, and to equate the working class either with the immigrant population or with ethnically Swedish “rednecks” isolated from urban “civilization.” Recently, however, two films have stood out by avoiding such “othering” stereotypes: Sebbe (2010) and Eat Sleep Die (2012). Both films were written and directed by filmmakers with an immigrant background: Iranian‐born Babak Najafi and Gabriella Pichler, whose Bosnian mother and Austrian father both arrived as migrant workers in the 1970s. Interestingly, the directors have chosen radically different approaches to the issue of the class–ethnicity relationship. Najafi focuses entirely on ethnically Swedish protagonists in Sweden's second largest city, Gothenburg, while Pichler situated her film among the ethnically mixed working class of a small industrial countryside town, giving her main protagonist a background similar to her own. This essay will comparatively analyze the two films against a background of contemporary Swedish history, while also highlighting how the immigrant and class experiences of the directors have beneficially influenced their work.
Class Struggle and Religious Difference in the Workplace: The Politics of Representing Islam in Rabah Ameur‐Zaïmeche's Dernier maquis (2008)
Authors: Higbee Will
Published: November 2013

The aim of this article is to explore how the 2008 film Dernier maquis, by Maghrebi‐French director Rabah Ameur‐Zaïmeche, attempts to correct a perceived absence in French cinema of Islam by focusing its narrative on the conflict that ensues between Mao, a French Muslim boss, and his Muslim immigrant workers, when Mao unilaterally appoints an imam to preside over the mosque he has constructed for his workers in a pallet yard located on a remote industrial estate on the outskirts of Paris. The article analyzes how, in Dernier maquis, Ameur‐Zaïmeche combines issues of class struggle and exclusion of the immigrant worker in contemporary France, with the potentially problematic place of ethnic and religious difference within the Republican nation.
Transverse Injection Into a Supersonic Cross Flow Through a Circular Injector With Chevrons
Authors: Hariharan Anand Raj , Babu V.
Published: November 2013

Results from 3D, compressible, unsteady Favre-averaged calculations of transverse injection into a supersonic cross flow are reported. Four injector geometries, namely, circular, wedge, diamond, and chevron, have been investigated. The effectiveness of the chevron injector is demonstrated by comparing performance metrics, such as degree of mixing and total pressure loss, against those of the other injectors. The results show that the chevron injector provides better mixing and spreading compared to other injectors, with almost the same total pressure loss. Furthermore, for the operating conditions studied, the chevron-penetration angle is shown to have a minimal impact on the mixing and the total pressure loss.
Fatigue Testing of Full Scale Girth Welded Pipes Under Variable Amplitude Loading
Authors: Zhang Y.-H. , Maddox S. J.
Published: November 2013

In the fatigue design of steel catenary risers, there are concerns regarding the fatigue damage to girth welds from low stresses, below the constant amplitude fatigue limit, in the loading spectrum and the validity of Miner's cumulative damage rule. These fundamental issues were addressed in a recent joint-industrial project (JIP). A key feature was development of the resonance fatigue testing rigs to enable them to test full-scale pipes under variable amplitude loading. Such tests were performed under a loading spectrum representative of that experienced by some risers, with many tests lasting over 100 million cycles to investigate the fatigue damage due to small stresses as well as the validity of Miner's rule. However, the resonance rigs are only capable of producing spectrum loading by gradually increasing or decreasing the applied load whereas more “spiky” random load sequences may be relevant in practice. Therefore, the program also included fatigue tests in conventional testing machines on strip specimens cut from pipes to compare the two types of loading sequence. This paper presents the results of these tests, conclusions drawn, and recommendations for changes to current fatigue design guidance for girth welded pipes regarding the definition of the fatigue limit, allowance for the damaging effect of low stresses, and the validity of Miner's rule.
Longitudinal Impact of Semi-Infinite Elastic Bars: Plane Any Time Solution
Authors: Malkov M. A.
Published: November 2013

Using the Sobolev–Smirnov method, we have found the exact analytical solution of a longitudinal impact of semi-infinite plane elastic bars for any time after the impact. After collision, there are loading waves from contact surfaces of bars and unloading waves from lateral surfaces. Then the unloading waves reach the opposite surface of the bars and create the reflected loading waves. These loading waves reach the other surface of the bars and generate new unloading waves. The number of waves grows exponentially. The sum of waves tends to the wave of the one-dimensional approximation.
User-Centered Design Customization of Rugby Wheelchairs Based on the Taguchi Method
Authors: Usma-Alvarez Clara C. , Fuss Franz K. , Subic Aleksandar
Published: November 2013

Competitive wheelchair sport performance is dependent on three factors: the athlete, the wheelchair, and the interaction between the athlete and the wheelchair (Goosey-Tolfrey, 2010, “Supporting the Paralympic Athlete: Focus on Wheeled Sports,” Disabil Rehabil., 32(26), pp. 2237–2243). In order to effectively refine the user interphase design of the wheelchair, it is essential to narrow down the key dimensions within the design space, which are likely to have an effect on the performance of an individual athlete. This paper provides a case study analysis of the test data obtained from five elite wheelchair rugby athletes, using a purpose-built adjustable wheelchair on a wheelchair ergometer. Four design factors (wheel diameter, camber angle, seat height, and camber bar depth) were tested at incremental dimensional levels to the athlete's current chair configuration; and tests were performed according to an L9 Taguchi orthogonal array. The case study analyzes acceleration, velocity, and time in the push phase of the propulsion cycle; as well as recovery time for each of the participating athletes performing a linear sprint task. The Taguchi method is applied to determining the positive/negative contribution of each of the four design factors to the outlined performance variables as well as their combined effect in a specific wheelchair configuration model. A performance ranking system and magnitude-based inferences on the true value of the effect statistic are used to define a high performance design space for individual athlete wheelchairs. Finally, the athlete's preferred ergonomics are considered to assess the narrowed high performance wheelchair options. As such, when adopting the approach presented in this paper, it becomes possible to customize an athlete's wheelchair design to meet the athlete's anthropometric needs as well as their performance requirements.
General Method for the Development of Gas Turbine Based Plant Simulators: An IGCC Application
Authors: Cerri Giovanni , Chennaoui Leila
Published: November 2013

An Energy Conversion Power Plant Simulator development is presented. The various aspects related to the identification of the problem to be solved (cycle calculation, component sizing, off-design component behaviour, components matching and Plant part load analysis) are discussed. Mathematical aspects are illustrated and the components physical models are discussed. Examples for validation purposes are shown. An application to the development of a Generic 300 MW F Class Gas Turbine to be fed with H2 Rich Syngas produced by an IGCC is illustrated.
The Effects of Biot Number on the Conjugate Film Cooling Effectiveness Under Different Blowing Ratios
Authors: Zhang Chao , Liu Jian-Jun , Wang Zhan , An Bai-Tao
Published: November 2013

Based on the one-dimensional heat transfer analysis of film cooled turbine blade, the correlation between overall cooling effectiveness and Biot number was obtained, where Biot number represents the ratio of the solid thermal resistance to the external convective heat transfer resistance. And a new parameter — net film cooling effectiveness was defined to evaluate the film cooling performance in the case of conjugate film cooling. Conjugate heat transfer simulation was carried out by using the commercial CFD package CFX for the typical cylindrical film cooling holes on flat plate. The influences of Biot number under different blowing ratios on laterally-averaged overall film cooling effectiveness, laterally-averaged and area-averaged net film cooling effectiveness were investigated systematically. The results showed that due to the effect of solid heat conduction, laterally averaged overall film cooling effectiveness is higher than adiabatic film cooling effectiveness, and the upstream region of the cooling hole can also be cooled by the coolant. With the decrease of Biot number, both the stream-wise and laterally overall cooling effectiveness are more uniform, and laterally-averaged net film cooling effectiveness is reduced. The trend of laterally-averaged net cooling effectiveness under different blowing ratios is consistent with the adiabatic case, but has lower values. For the engine-like Biot number Bi = 0.36, compared with the low blowing ratio M = 0.5 case, the value of area-averaged net film cooling effectiveness is reduced about 29% and 65% correspondingly under blowing ratio M = 1.0 and M = 1.5.
Steam Cycle Simulator for CHP Plants
Authors: Cerri Giovanni , Mazzoni Stefano , Salvini Coriolano
Published: November 2013

This paper describes a methodology to set up steam cycle simulators for CHP plants. The adopted approach consists in a simultaneous solution of modules representing plant components taking their actual behavior into account. Models are characterized by Reality Functions to adapt them to the reality of machines and apparatuses so that the New&Clean map of the real component can be established. Furthermore, to account for deterioration phenomena occurring during plant operations, Actuality Functions affecting component performance in terms of work and heat transfer, losses and effective flow functions have been introduced. Models have been validated and tested against real CHP plant data. Applications to different kinds of CHP steam cycles are presented and discussed. Results show a good simulator capability to estimate component deterioration status and to reproduce the plant actual behavior.
Experimental Study: Effects of the Annulus’ Center Body End Shape on the Performance of Low Mach Number Air-Air Ejector With Entraining Diffuser
Authors: Namet-Allah A. , Birk A. M.
Published: November 2013

In the present paper, an experimental investigation of the performance of a low mach number round straight air-air ejector with a 4-ring entraining diffuser is reported. The ejector system was mounted on an annular flow wind tunnel. Based on the hydraulic diameter and average velocity and temperature at the nozzle exit, the tunnel provides cold flow at Mach 0.2 with a Reynolds number of 5.2×105 and hot flow at Mach 0.27 with a Reynolds number of 2.6×105.

The end shape of the annulus’ center body has major effects on the core separation size and shape that strongly affects the ejector performance. The effects of the annulus’ center body with elliptical and square ends on the ejector pumping, wall static pressure distribution and back pressure were investigated under different flow temperatures and swirl angles: 0°, 10°, 20°, and 30°. These measurements were conducted at 129 mm standoff distance using two different nozzle exit diameters.

It was found that for both nozzle exit diameters, using the annulus’ center body with a square end improved the total pumping ratio over its ratio with an elliptical end due to the flatness of the core separation at the nozzle exits. For all configurations tested, the maximum entrainment ratio was observed with 20° swirl angle and the back pressure coefficient decreased as swirl angle increased. Removing the elliptical end, creating the square shape, the flow has more space to spread after the annulus’ center body to give the higher centerline velocity which enhances the flow uniformity at the nozzle and diffuser exits.
Using CFD to Enhance the Preliminary Design of High-Pressure Steam Turbines
Authors: Bellucci Juri , Sazzini Federica , Rubechini Filippo , Arnone Andrea , Arcangeli Lorenzo , Maceli Nicola
Published: November 2013

This paper focuses on the use of the CFD for improving a steam turbine preliminary design tool.

Three-dimensional RANS analyses were carried out in order to independently investigate the effects of profile, secondary flow and tip clearance losses, on the efficiency of two high-pressure steam turbine stages. The parametric study included geometrical features such as stagger angle, aspect ratio and radius ratio, and was conducted for a wide range of flow coefficients to cover the whole operating envelope. The results are reported in terms of stage performance curves, enthalpy loss coefficients and span-wise distribution of the blade-to-blade exit angles. A detailed discussion of these results is provided in order to highlight the different aerodynamic behavior of the two geometries.

Once the analysis was concluded, the tuning of a preliminary steam turbine design tool was carried out, based on a correlative approach. Due to the lack of a large set of experimental data, the information obtained from the post-processing of the CFD computations were applied to update the current correlations, in order to improve the accuracy of the efficiency evaluation for both stages. Finally, the predictions of the tuned preliminary design tool were compared with the results of the CFD computations, in terms of stage efficiency, in a broad range of flow coefficients and in different real machine layouts.
High-Temperature Interlaminar Tension Test Method Development for Ceramic Matrix Composites
Authors: Engel Todd
Published: November 2013

Ceramic Matrix Composite (CMC) materials are an attractive design option for various high-temperature structural applications. In particular, the use of CMC materials as a replacement for state-of-the-art nickel-based superalloys in hot gas path turbomachinery components offers the potential for significant increases in turbine system efficiencies, due largely to reductions in cooling requirements afforded by the increased temperature capabilities inherent to the ceramic material. However, two-dimensional fabric-laminated CMCs typically exhibit low tensile strengths in the thru-thickness (interlaminar) direction, and interply delamination is a concern for some targeted applications. Currently, standardized test methods only address the characterization of interlaminar tensile strengths at ambient temperatures; this is problematic given that nearly all CMCs are slated for service in high-temperature operating environments. This work addresses the development of a new test technique for the high-temperature measurement of interlaminar tensile properties in CMCs, allowing for the characterization of material properties under conditions more analogous to anticipated service environments in order to yield more robust component designs.
Experimental Investigation of Performance of an Air Blast Atomizer by Planar Laser Sheet Imaging Technique
Authors: Liu Cunxi , Liu Fuqiang , Mao Yanhui , Mu Yong , Xu Gang
Published: November 2013

It is widely recognized that the fuel/air mixing process is a critical factor in improving combustion efficiency and in minimizing pollutants such as NOx. Enhancement of fuel/air mixing can lead to lower pollutant emissions and greater efficiency. However, swirling flows in lean combustors play the role of fuel/air mixing and flame stability. The complex fluid dynamic phenomena encountered in swirling two-phase flow contribute to the difficulty in complete understanding the different processes occurring in combustors. Fortunately, Optical and laser-based visualization techniques available in our lab are important non-intrusive tools for visualizing flow process, especially for fuel injection and fuel/air mixing. To provide for a better understanding of effects of counter-rotating flow on droplets in atomization process, this study is a detailed characterization of the spray generated by an airblast atomizer by planar laser sheet imaging method.

Optical facility for spray diagnostics with fuel Planar Laser Induced Fluorescence (fuel-PLIF) method for fuel distribution, and Particle Image Velocity (PIV) method for velocity of droplets, is used to evaluate the performance of an air-blast atomizer. The results show that the performance of secondary atomization is influenced by swirling flow and primary atomization simultaneously, the swirling flow exhibits significant influence on the droplet size and space distribution relative to that of primary atomization. The primary swirling air reopens the spray cone generated by pressure-swirl atomizer, and the secondary swirling air affects the fuel distribution by forming the recirculation zone. The results provide critical information for design and development of combustion chamber.
Design for Thermo-Acoustic Stability: Procedure and Data Base
Authors: Bade Stefanie , Wagner Michael , Hirsch Christoph , Sattelmayer Thomas , Schuermans Bruno
Published: November 2013

A Design for Thermo-Acoustic Stability (DeTAS) procedure is presented, that aims at selecting a most stable burner geometry for a given combustor. It is based on the premise that a thermo-acoustic stability model of the combustor can be formulated and that a burner design exists, which has geometric design parameters that sufficiently influence the dynamics of the flame. Describing the burner and flame dynamics in dependence of the geometrical parameters an optimization procedure involving a linear stability model of the target combustor maximizes the damping and thereby yields the optimal geometrical parameters. To demonstrate the procedure on an existing annular combustor a generic burner design was developed that features two geometrical parameters that can easily be adjusted. To provide the data base for the DeTAS procedure static and dynamical properties of burner and flame were measured for three by three configurations at a fixed operation point. The data is presented and discussed. It is found that the chosen design exhibits a significant variability of the flame dynamics in dependence of the geometrical parameters indicating that a DeTAS should be possible for the targeted annular combustor.
Advancement in Heated Spin Testing Technologies
Authors: Endo Hiroaki , Wetherbee Robert , Kaushal Nikhil
Published: November 2013

An ever more rapidly accelerating trend toward pursuing more efficient gas turbines pushes the engines to hotter and more arduous operating conditions. This trend drives the need for new materials, coatings and associated modeling and testing techniques required to evaluate new component design in high temperature environments and complex stress conditions.

This paper will present the recent advances in spin testing techniques that are capable of creating complex stress and thermal conditions, which more closely represent “engine like” conditions. The data from the tests will also become essential references that support the effort in Integrated Computational Materials Engineering (ICME) and in the advances in rotor design and lifing analysis models. Future innovation in aerospace products is critically depended on simultaneous engineering of material properties, product design, and manufacturing processes. ICME is an emerging discipline with an approach to design products, the materials that comprise them, and their associated materials processing methods by linking materials models at multiple scales (Structural, Macro, Meso, Micro, Nano, etc). The focus of the ICME is on the materials; understanding how processes produce material structures, how those structures give rise to material properties, and how to select and/or engineer materials for a given application [34].

The use of advanced high temperature spin testing technologies, including thermal gradient and thermo-mechanical cycling capabilities, combined with the innovative use of modern sensors and instrumentation methods, enables the examination of gas turbine discs and blades under the thermal and the mechanical loads that are more relevant to the conditions of the problematic damages occurring in modern gas turbine engines.
Heat Transfer Measurements in Rotating Blade-Shape Serpentine Coolant Passage With Ribbed Walls at High Reynolds Numbers
Authors: Rallabandi Akhilesh , Lei Jiang , Han Je-Chin , Azad Salam , Lee Ching-Pang
Published: November 2013

Flow in the internal three-pass serpentine rib turbulated passages of an advanced high pressure rotor blade is simulated on a 1:1 scale in the laboratory. Tests to measure the effect of rotation on the Nusselt number are conducted at rotation numbers up to 0.4 and Reynolds numbers from 75,000 to 165,000. To achieve this similitude, pressurized Freon R134a vapor is utilized as the working fluid. Experimental heat transfer coefficient measurements are made using the copperplate regional average method. Regional heat transfer coefficients are correlated with rotation numbers. An increase in heat transfer rates due to rotation is observed in radially outward passes; a reduction in heat transfer rate is observed in the radially inward pass. Strikingly, a significant deterioration in heat transfer is noticed in the “hub” region — between the radially inward second pass and the radially outward third pass. This heat transfer reduction is critical for turbine cooling designs.
Study on Relevant Effects Concerning Heat Transfer of a Convection Cooled Gas Turbine Blade Under Realistic Engine Temperature Conditions
Authors: Mick Y. , Wörz B. , Findeisen E. , Jeschke P. , Caspary V.
Published: November 2013

This paper presents a study of the temperature distribution of a convection cooled gas turbine blade under realistic operating temperature conditions using experimental and numerical methods. The analysis is performed experimentally in a linear cascade with exhaust gas from a kerosene combustor. Detailed information at different operating points is taken from the experiments for which conjugate heat transfer (CHT) simulations with ANSYS CFX are carried out. By comparing the experimental and numerical results, the required complexity of the simulations is defined.

The subject of this study is a gas turbine rotor blade equipped with a state-of-the-art internal convection cooling system. The test rig enables the examination of the blade at temperatures up to 1300K. The temperature distribution of the blade is measured using thermocouples. The calculations are carried out using the SST turbulence model, the Gamma Theta transition model and the discrete transfer radiation model. The influence of hot gas properties and radiation effects are analysed at three different operating points. This paper gives a quantitative overview of the impact of the mentioned parameters on temperature level and distribution as well as thermal stresses in a convection cooled blade under realistic engine temperature conditions.