bluuebunny/crossref_metadata_2025 huggingface dataset:
Fatal Myocarditis Following Treatment with the PD‐1 Inhibitor Nivolumab
Authors: Matson Daniel R. , Accola Molly A. , Rehrauer William M. , Corliss Robert F.
Published: August 2017

Therapeutic antibodies targeting the programmed cell death protein 1 (PD‐1) pathway function as immune checkpoint inhibitors, allowing the immune system to recognize tumors which otherwise escape immune surveillance. However, these agents can also elicit an autoimmune response by inhibiting the ability of non‐neoplastic tissues and regulatory cells to suppress the immune system. Here we present a fatal case of active myocarditis in a 55‐year‐old man with non‐small‐cell lung cancer which occurred following monotherapy with the PD‐1 inhibitor nivolumab (Opdivo). He presented with acute right‐sided heart failure and died 1 day after admission. Postmortem examination revealed multiple gelatinous lesions in the myocardium of the interventricular septum and the bilateral atria and ventricles which had microscopic features diagnostic of myocarditis. Subsequent studies failed to identify an infectious cause. Immune checkpoint inhibitors are an increasingly common addition to anticancer regimens and they should be considered in the evaluation of acute myocarditis.
Do you see what I see: A mother's plea
Authors: Nydam Kees , Soole Rebecca
Published: August 2017

There is sometimes dissonance between the medical services that the general public expects an ED to provide and the acute critical care that emergency clinicians hope to provide. One explanation for this is that the ED is both a territory and a meeting place for a cornucopia of clinicians, some of whom are not ED clinicians themselves. Roles are sometimes ambiguous and location‐specific. Recently, one Queensland mother believed that her son's suicide could have been prevented had emergency staff been better educated. This perspective aims to reflect on several pertinent questions: Should suicide risk be treated as a medical emergency? Is suicide prevention everyone's business? Is suicide risk assessment and management a core component of ED? How common, precise and non‐stigmatising is the language around suicide? To what extent is that language underpinned by mythology rather than fact? For some, these will be inconvenient questions. How they are answered is undoubtedly framed within the language used when discussing suicide.
First detection of Russian wheat aphid Diuraphis noxia Kurdjumov (Hemiptera: Aphididae) in Australia: a major threat to cereal production
Authors: Yazdani Maryam , Baker Greg , DeGraaf Helen , Henry Ken , Hill Kelly , Kimber Bill , Malipatil Mallik , Perry Kym , Valenzuela Isabel , Nash Michael A
Published: August 2017

Invasive pest species pose a major threat to agricultural production around the world. Until recently, the Russian wheat aphid, Diuraphis noxia Kurdjumov, a major pest of wheat and barley crops worldwide, was considered a high‐priority exotic pest threat to the Australian grains industry. Here, we document the initial detection and establishment of D. noxia in Australia in 2016. These are the first records for this genus from South Australia, Victoria and New South Wales. Morphological and molecular information is presented for confirmed diagnosis of the species based on voucher specimens. Known distribution data are provided, along with a list of Poaceae hosts on which D. noxia has been recorded, and a brief description of the typical damage symptoms caused by these aphids. The potential impact of this aphid on Australian cereal production is discussed, and we identify research areas required to underpin future management of this new threat to the Australian cereal industry.
Biopesticide effects on pupae and adult mortality ofAnastrepha fraterculusandCeratitis capitata(Diptera: Tephritidae)
Authors: Oviedo Andrea , Van Nieuwenhove Guido , Van Nieuwenhove Carina , Rull Juan
Published: August 2017

Reliance on broad spectrum insecticides for pest control has led to significant environmental damage, human health problems and rapid evolution of insect resistance. These shortcomings have caused a renewed interest in exploring biologically based pest control methods. Among these, the use of plant essential oils, hydrolates and other natural products offer a promising alternative to broad spectrum pesticides. Here, we explored the effect of several bioproducts on pupal and adult mortality (through contact and ingestion) of the two most important pest species of fruit production in South America, South American fruit fly,Anastrepha fraterculusand Medfly,Ceratitis capitata. Topical application of different bioproducts produced different effects on pupal mortality ofA. fraterculusandC. capitata.Essential oils ofBaccharis dracunculifoliaandPinus elliottii,both containing high proportions of α and β‐pinene and limonene (among other compounds), caused 100% mortality onC. capitatapupae and strongly suppressed adult eclosion ofA. fraterculusin comparison with controls. Extracts ofSolanum granulosumplusRicinus communisalso caused a moderate yet significant reduction in adult eclosion when compared with the control. All other tested products had no effect on adult emergence. Toxicity on adults through ingestion was greatest for extracts ofS. granulosumplusR. communis, followed by Spinosad (Flipper®) andB.dracunculifoliaoil (although in these two cases survival was above 40%), while other tested products had no effect on adult mortality. We discuss future research and the potential use of some of the tested products as a component for rational pest management strategies.
Energy, households, gender and science: A feminist retrofit framework for transdisciplinary research
Authors: Waitt Gordon
Published: August 2017

The energy field is characterised by an unusual degree of transdisciplinary research. At a moment when transdisciplinary work is valued within certain policy realms for its more apparent relevance and problem‐solving attributes to global challenges, it is therefore helpful to consider frameworks that may facilitate such research. To do so, this paper explores how feminist geographers might help recognise and mitigate against the imbalances of power in relationships between researchers from different disciplines by carefully considering questions of epistemology and methodology in collaborative projects. Attentive to the feminist concepts of “situated knowledge” and “reflexivity”, this paper examines what constitutes acceptably scholarly knowledge on domestic energy. The paper thus proposes a feminist retrofit framework (FRF) with three components: (1) gendered science and knowledge of domestic energy efficiency; (2) everyday knowledge of domestic energy efficiency; and (3) experimental participatory approaches to investigating energy efficiency. By bringing into conversation feminist science studies and feminist post‐structuralist geography, the proposed FRF facilitates rigorous analyses of gender, power and epistemologies in energy research. To illustrate one way to achieve more equitable energy research and interventions, the paper draws on three events in which [self‐]reflexivity contests and extends conventional approaches to conducting a domestic energy project with older low‐income households in a regional centre of New South Wales, Australia.
Look to the past for an optimistic future
Authors: O'Dea Aaron , Dillon Erin M. , Altieri Andrew H. , Lepore Mauro L.
Published: August 2017

Article impact statement: With greater integration between paleontologists and conservationists, the fossil record can be a positive force in conservation.
Relationships between central arterial stiffness, lean body mass, and absolute and relative strength in young and older men and women
Authors: Fahs Christopher A. , Thiebaud Robert S. , Rossow Lindy M. , Loenneke Jeremy P. , Bemben Debra A. , Bemben Michael G.
Published: August 2017

Relationships between muscular strength and arterial stiffness as well as between muscle mass and arterial stiffness have been observed suggesting a link between the neuromuscular system and vascular health. However, the relationship between central arterial stiffness and absolute and relative strength along with muscle mass has not been investigated in both sexes across a broad age range. The purpose of this study was to examine the relationship between central arterial stiffness and absolute and relative strength as well as between central arterial stiffness and lean body mass (LBM) in men and women across a broad age range. LBM, central arterial stiffness and strength were measured on 36 men and 35 women between the ages of 18 and 75 years. Strength was measured on five machine resistance exercises and summed as one measure of overall strength (absolute strength). Relative strength was calculated as total strength divided by LBM (relative strength). Central arterial stiffness was inversely related to both absolute (r = −0·230; P = 0·029) and relative strength (r = −0·484; P < 0·001) but not LBM (r = 0·097; P = 0·213). The relationship between central arterial stiffness and relative strength was attenuated but still present when controlling for either age, per cent body fat, LBM or mean arterial pressure. These results suggest that, across a wide age range, the expression of relative muscular strength has a stronger relationship with central arterial stiffness compared to either LBM or absolute strength. This suggests that muscle function more than muscle mass may be coupled with vascular health.
Multiple progressive annular telangiectasias: A clinicopathological variant of cutaneous collagenous vasculopathy?
Authors: García‐Martínez Pablo , Gomez‐Martin Ignacio , Lloreta Josep , Pujol Ramon M
Published: August 2017

Telangiectasias are the clinical manifestation of diverse processes affecting blood vessels. Herein we report the case of a 60‐year‐old man presenting long‐standing asymptomatic annular telangiectatic lesions with whitish centers. The histopathologic examination revealed thickened blood dermal vessel walls in the superficial dermis showing reduplication of the basement membrane resembling cutaneous collagenous vasculopathy (CCV). We suggest that this atypical clinicopathological presentation may represent either a localized annular variant of CCV or a previously unreported clinical form of multiple cutaneous telangiectasias.
Oviposition responses of Queensland fruit fly (Bactrocera tryoni) to mineral oil deposits on tomato fruit
Authors: Nguyen V. L. , Beattie G. A. C. , Meats A. W. , Holford P. , Spooner‐Hart R. N.
Published: August 2017

Behavioural responses of wild and laboratory‐culture females of Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), to mineral oil deposits on tomato fruit dipped in aqueous oil emulsions were assessed in a no‐choice test and three choice tests. The oils were two commercial products used to manage plant pests and diseases, Ampol D‐C‐Tron NR and SK EnSpray 99, one distillation fraction of the base oil of the former, and four distillation fractions of the base oil of the latter. The initial and final boiling points of the fractions were equivalent to those of n‐alkanes with chain lengths of C20–22 (Ampol), and C21–C23, C22–23.5, C22–24, and C22–24.5 (SK). For both fly types in the no‐choice test, numbers of punctures and eggs per fruit declined strongly as concentrations of the nC20–22 Ampol fraction in emulsions rose from 0.25 to 2% (vol/vol). Fly type affected the extent of responses but there was no significant interaction for fly type*oil concentration. Responses of laboratory‐culture females in the choice tests also declined as concentrations of SK and the four fractions of its base oil in emulsions rose from 0 to 0.25%. The SK nC22–24 and nC22–24.5 fractions had least impact. Responses of laboratory‐culture flies to 0.5% emulsions of the nC20–22 Ampol fraction and the nC21–23 SK fraction in choice tests were not significantly different. Likewise, responses of laboratory‐culture flies to 0.5% emulsions of the two commercial products were not significantly different. Emulsifier type did not affect numbers of punctures or eggs per fruit in choice responses of laboratory‐culture flies to 0.5% emulsions of the Ampol nC20–22 fraction or 0.5% emulsions of the SK nC21–23 fraction. If the equivalence of no‐choice and choice responses in the laboratory were to hold in the field, then unsprayed ‘sacrificial’ plants would not be necessary and oil emulsions could be used as cover sprays.
Applying a Danish version of the Learning Transfer System Inventory and testing it for different types of education
Authors: Soerensen Peter , Stegeager Nikolaj , Bates Reid
Published: August 2017

The purpose of this study was to answer two research questions. First, will an exploratory factor analysis of a Danish version of the Learning Transfer System Inventory (LTSI) result in a factor structure which is consistent with the original American LTSI factor structure? Second, does the mean score in the factor analysis vary in a statistically significant way across different types of education, suggesting that the LTSI may be more suitable a measure in some educational contexts than others? To answer these questions survey data from 411 students following four different types of formal education – adult vocational training, academy profession programs, diploma programs and master's degree programs – were analysed. Principal component analysis was used to answer research question one. Factorial ANOVA was used to answer question two. The analysis resulted in fewer factors than in the original American LTSI. The study also found that the mean score differs in a statistically significant way between the different types of education. Specifically, LTSI may be more suitable in measuring transfer systems and therefore promoting transfer in relation to short courses offering training in specific skills than in relation to long‐term continuing education.
Real‐world efficacy and safety of ombitasvir, paritaprevir/r+dasabuvir+ribavirin in genotype 1b patients with hepatitis C virus cirrhosis
Authors: Preda Carmen M. , Popescu Corneliu P. , Baicus Cristian , Voiosu Theodor A. , Manuc Mircea , Pop Corina Silvia , Gheorghe Liana , Sporea Ioan , Trifan Anca , Tantau Marcel , Tantau Alina , Ceausu Emanoil , Proca Doina , Constantinescu Ileana , Ruta Simona M. , Diculescu Mircea M. , Oproiu Alexandru
Published: August 2017

Background

Direct antiviral agents (DAA) showed very good results in terms of efficacy and safety in clinical trials, but real‐life data are still needed in order to confirm this profile.

Material and methods

In Romania, through a nationwide government‐funded programme in 2015‐2016, approx.5800 patients with virus C cirrhosis received fully reimbursed DAA therapy with OBV/PTV/r+DSV+RBV for 12 weeks. We analysed a national prospective cohort enrolling the first 2070 patients, all with genotype 1b. The only key inclusion criteria was advanced fibrosis (Metavir stage F4) confirmed by Fibromax testing (or liver biopsy/Fibroscan). Efficacy was assessed by the percentage of patients achieving SVR 12 weeks post‐treatment (SVR12).

Results

Forty patients stopped the treatment because of hepatic decompensation (1.9%), 21 stopped because of other adverse events and one was lost to follow‐up. This cohort was 51% females, mean age 60 years (25÷82), 67% pretreated, 70% associated NASH, 67% with severe necro‐inflammation (severity score 3‐Fibromax), 37% with comorbidities, 10.4% with Child Pugh A6, 0.5% B7. The median MELD score was 8.09 (6 ÷ 22). SVR by intention‐to‐treat was reported in 1999/2070(96.6%), 55/2070 failed to respond. Liver decompensation was statistically associated in multivariate analysis with platelets< 105/mm3(P = .03), increased total bilirubin (P < .001), prolonged INR (P = .02), and albumin<3.5 g/dL (P = .03).

Conclusions

OBV/PTV/r+DSV+RBV proved to be highly efficient in our population of cirrhotics with a 96.6% SVR. Serious adverse events related to therapy were reported in 61/2070(2.9%), most of them liver decompensation (1.9%), related to hepatic dysfunction, and lower platelet count.
Late Pleistocene and Holocene chamois in Italy
Authors: Masseti Marco , Salari Leonardo
Published: August 2017

Two species of chamois currently live in Italy: Rupicapra rupicapra, with the subspecies Rupicapra rupicapra rupicapra, the Alpine chamois, and Rupicapra pyrenaica, with the subspecies Rupicapra pyrenaica ornata, the Apennine chamois.

Late Pleistocene and Holocene remains of chamois are numerous, but those attributable with reasonable certainty at the species or subspecies level are few and are mostly poorly dated.

The recent finding of a sub‐complete partially articulated skeleton of chamois attributed to Rupicapra pyrenaica ornata, from Late Pleistocene sediments of Grotta Mora Cavorso (Simbruini Mountains, central Italy), provides new data and insights on the taxonomy and distribution of the genus Rupicapra in the Late Pleistocene and Holocene of Italy. Indeed, so far this subspecies was known with certainty only from Holocene and, possibly, in Lateglacial deposits.

From the current state of knowledge, it seems that the populations of southern chamois (Iberian and Apennine chamois), which had been living in Western Europe since the Middle Pleistocene, were separated by a dispersal wave of northern chamois (Alpine chamois) at least as far back as the latest Middle Pleistocene, earlier than previously thought.

The hypothesis of the anthropochorous origin of the extant chamois population of Abruzzo appears no longer to be convincing: the Iberian chamois allegedly imported from Spain to southern Italy during the 18th and 19th Centuries do not appear to have contributed to the genetic heritage of the extant Apennine chamois.
Typhonium muaklekense sp. nov. (Araceae) from Thailand
Authors: Sookchaloem Duangchai , Maneeanakekul Sutida
Published: August 2017

Typhonium muaklekense D. Sookchaloem & S. Maneeanakekul is described and illustrated. This new species resembles T. roxburghii Schott and T. varians Hett. & Sookch. in the spathe. Drawings, photographs and a table comparing diagnostic features of T. muaklekense, T. roxburghii and T. varians are provided.
The Effect of Sale Methods on the Interest Rate of Municipal Bonds: A Heterogeneous Endogenous Treatment Estimation
Authors: Liu Gao
Published: August 2017

Conventional wisdom argues that competitive bidding, compared to negotiated sale, can reduce the interest cost of municipal bonds in the primary market. Studies correcting for self‐selection bias have mixed findings. However, these studies are subject to some potential methodological issues. This study circumvents these pit‐falls and provides an estimate of the heterogeneous average treatment effect (ATE). After correcting for the endogeneity bias of sale method and its interaction effect, on average competitive sale still significantly lowers the interest rate, but the interest cost advantage decreases as issuer experience increases.
Complementarity, Linkages between Firms, and the Effect of Entry Costs on Productivity
Authors: del Rio Fernando , Sampayo Antonio
Published: August 2017

In a general equilibrium model where firms are heterogeneous in terms of productivity, we introduce differentiated goods in production that are not perfect substitutes, as well as intermediate inputs needed to produce those goods. We show that an increase in either the complementarity of differentiated goods or the share of intermediate inputs in gross output, significantly increases the negative effect of entry costs on total factor productivity (TFP) and output per worker. We also find that the effect of complementarity is quantitatively stronger. If we assume an empirically plausible value for the elasticity of substitution between differentiated goods, then the model considerably improves its ability to reproduce the observed negative relationship between entry costs and TFP or output per worker.
Effects of intergroup exclusion on individual needs threat and behavior tendencies
Authors: Yang Xiao Li , Wei Li , Zhao Qing Hua , Liu Li
Published: August 2017

This study explores the effects of intergroup exclusion on need‐threat and the behavioral tendencies of excluded individuals. Results show that those excluded by in‐group members perceived more threat to relational needs, while participants excluded by out‐group members perceived more threat to efficacy needs. In addition, participants excluded by out‐group members displayed significantly more aggression intention and less helping intention than those who were excluded by in‐group members. This study indicates that the group relationship between excluders and the excluded will directly affect threat perception and behavioral responses.
Multi‐Scale Meta‐Governance Strategies for Addressing Social Inequality in Resource Dependent Regions
Authors: Wilson Ceit E. , Morrison Tiffany H. , Everingham Jo‐Anne
Published: August 2017

Social inequality in resource‐dependent regions is a growing problem. Increasingly both state and private actors are acting as meta‐governors to address the issue. In this article, we focus on housing inequality as ‘the canary in the coalmine’ for broader social inequality. While affordable housing has been the subject of growing attention in urban scholarship, relatively few studies have considered the governance of affordable housing in rural regions. We report on a case analysis of affordable housing governance in the Gladstone‐Surat Region, a traditional agricultural area of Australia that has experienced a dramatic increase in housing inequality due to significant coal seam gas development in recent years. We show that networked arrangements for affordable housing delivery were the product of strategic policy structuring, resourcing, and hands‐off framing by the state government. Private meta‐governance was exercised only in relation to process management forms of meta‐governance, with private companies facilitating local ‘arenas’ for stakeholder discussion and connecting stakeholders in a synergistic manner. The dynamics of the case‐study examined demonstrate that meta‐governance in rural regions is not just about coordinating and mobilising horizontal (e.g., regional) cooperation, but about coalescing action within multiscale ‘exogenous’ networks and structures. These findings have important implications for future efforts to address social inequality in rural areas.
Critical interpretive synthesis of barriers and facilitators to TB treatment in immigrant populations
Authors: Lin S. , Melendez‐Torres G. J.
Published: August 2017

Objective

To systematically review studies of TB treatment experiences in immigrant populations, using Critical Interpretive Synthesis (CIS).

Methods

On 26 October 2014, MEDLINE, CINAHL, Embase, LILACS, and PsycINFO were systematically searched. Grey literature and reference lists were hand‐searched. Initial papers included were restricted to studies of immigrant patient perspectives; after a model was developed, a second set of papers was included to test the emerging theory.

Results

Of 1761 studies identified in the search, a total of 29 were included in the synthesis. Using those studies, we developed a model that suggested treatment experiences were strongly related to the way both individuals and societies adjusted to immigration (‘acculturation strategies’). Relationships with healthcare workers and immigration policies played particularly significant roles in TB treatment.

Conclusions

This review emphasised the roles of repatriation policy and healthcare workers in forming experiences of TB treatment in immigrant populations.
The Transfer Matrix Metamodel for Dynamic Systems With Arbitrary Time-Variant Inputs
Authors: Savage Gordon J. , Son Young Kap
Published: August 2017

This paper addresses the problem of mapping a vector of input variables (corresponding to discrete samples from a time-varying input) to a vector of output variables (discrete samples of the time-dependent response). This mapping is typically performed by a mechanistic model. However, when the mechanistic model is complex and dynamic, the computational effort to iteratively generate the response for design purposes can be burdensome. Metamodels (or, surrogate models) can be computationally efficient replacements, especially when the input variables have some amplitude and frequency bounds. Herein, a simple metamodel in the form of a transfer matrix is created from a matrix of a few training inputs and a corresponding matrix of matching responses provided by simulations of the dynamic mechanistic model. A least-squares paradigm reveals a simple way to link the input matrix to the columns of the response matrix. Application of singular value decomposition (SVD) introduces significant computational advantages since it provides matrices whose properties give, in an elegant fashion, the transfer matrix. The efficacy of the transfer matrix is shown through an investigation of a nonlinear, underdamped, double mass–spring–damper system. Arbitrary excitations and selected sinusoids are applied to check accuracy, speed and robustness of the methodology. The sources of errors are identified and ways to mitigate them are discussed. When compared to the ubiquitous Kriging approach, the transfer matrix method shows similar accuracy but much reduced computation time.
A Study About Performance Evaluation Criteria of Tube Banks With Various Shapes and Arrangements Using Numerical Simulation
Authors: Jodaei Amin , Zamzamian Kamiar
Published: August 2017

Tube bank heat exchangers are designed to efficiently transfer heat between two fluids. Shapes and arrangements of tubes in heat exchangers have significant effects in heat transfer and pressure drop of fluid. In this study, the three-dimensional (3D) numerical investigation is performed to determine heat transfer coefficients, friction factor, and performance evaluation criteria (PEC) of cam-shaped tube banks in aerodynamic and inverse aerodynamic directions in the cross flow air and compared with those of elliptical tube banks in heat exchanger. The arrangements of tubes are aligned and staggered with longitudinal pitch of 44.88 mm and transverse pitch of 28.05 mm. Reynolds number in the range of 11,500–18,500 was used, and the tube surface temperature was fixed and considered 352 K. Results indicate the superior heat transfer of elliptical tube bank over the cam-shaped tube banks in inverse aerodynamic and aerodynamic directions in both arrangements. Moreover, the PEC of the cam-shaped tube banks with inverse aerodynamic and aerodynamic directions and elliptical tube bank in aligned arrangement are approximately 1.4, 1.1, and 1.6, respectively. The obtained results for staggered arrangements are also 1.5, 1.3, and 1.8, respectively.
Selection of the Optimum Control Parameters for Compressor Design Optimization Algorithm
Authors: Kilchyk Viktor , Senay Emily , Abdelwahab Ahmed
Published: August 2017

Topology optimization in turbomachinery is a challenging nonlinear problem with a large number of variables. Compressor efficiency function is dependent on the particular design space and may complicate due to numerical (CFD) solution issue. This makes it difficult to provide high precision, fast convergence, and robustness that is required by a modern, fast paced manufacturing environment. Even the best optimization algorithms exhibit difficulties in addressing these issues. To resolve these difficulties, a new algorithm testing, and training approach was proposed. In the new approach, training function is specially constructed using compressor efficiency function. Efficiency is determined by a combination of analytically derived individual loss functions. To account for some numerical issues associated with automated CFD runs, the obtained efficiency function modified to include solution randomness (noise). After testing most common optimization algorithm, genetic algorithm and pattern search algorithm were selected for training. The training process was automated using nested optimization loops. First, in the inner optimization loop, the best impeller geometry is found. Then in the outer optimization loop, optimum optimization algorithm parameters are found. Comparison of the trained and non-trained algorithm performance demonstrated a positive impact of the new approach. Optimized for compressor efficiency algorithm demonstrated improvement in both convergence precision (over 2% points) and convergence time. Extending the present approach to include other loss mechanisms and CFD generated data is proposed for future work.
Assessment of Bearing Heat Generation Prediction by the Program ADORE With Respect to Experimental Results and SHABERTH Predictions
Authors: Nicholson Brian D. , Givan Garry D. , Thompson Kevin L. , Mason Justin , Gupta Pradeep K. , Trivedi Hitesh K.
Published: August 2017

This work details the heat generation analysis of a turbine aero-engine main-shaft bearing using the computer program Advanced Dynamics Of Rolling Elements (ADORE). The empirical models used for traction and churning heat generation are detailed. The predictions of ADORE are shown to demonstrate the differing contributions of traction and churning to total heat generation at different load/speed regimes. These results are then compared with experimental results. In addition, the results of ADORE are also compared with results from the well-known bearing analysis program SHABERTH (Shaft Bearing Thermal Analysis). The comparisons showed good agreement between ADORE and the experimental results for loads between 13.35 and 53.40 kN and speeds between 1.8 and 2.2 MDN. The results also showed under prediction of heat generation by SHABERTH in this regime. Limitations of both programs were identified and speculated to include limitations in the empirical models due to the lack of available experimental traction data at high speeds/loads. Finally, recommendations for future research are provided which will likely provide significant improvements in the ability to predict bearing heat generation in turbine aero-engine applications.
Analysis of the Effect of Multi-Row and Multi-Passage Aerodynamic Interaction on the Forced Response Variation in a Compressor Configuration: Part 2 — Effects of Additional Structural Mistuning
Authors: Gross Johann , Krack Malte , Schoenenborn Harald
Published: August 2017

The prediction of aerodynamic blade forcing is a very important topic in turbomachinery design. Usually, the wake from the upstream blade row and the potential field from the downstream blade row are considered as the main causes for excitation, which in conjunction with relative rotation of neighboring blade rows, give rise to dynamic forcing of the blades. In addition to those two mechanisms so-called Tyler-Sofrin (or scattered or spinning) modes, which refer to the acoustic interaction with blade rows further up- or downstream, may have a significant impact on blade forcing. In particular, they lead to considerable blade-to-blade variations of the aerodynamic loading. In part 1 of the paper a study of these effects is performed on the basis of a quasi 3D multi-row and multi-passage compressor configuration.

Part 2 of the paper proposes a method to analyze the interaction of the aerodynamic forcing asymmetries with the already well-studied effects of random mistuning stemming from blade-to-blade variations of structural properties. Based on a finite element model of a sector, the equations governing the dynamic behavior of the entire bladed disk can be efficiently derived using substructuring techniques. The disk substructure is assumed as cyclically symmetric, while the blades exhibit structural mistuning and linear aeroelastic coupling. In order to avoid the costly multi-stage analysis, the variation of the aerodynamic loading is treated as an epistemic uncertainty, leading to a stochastic description of the annular force pattern. The effects of structural mistuning and stochastic aerodynamic forcing are first studied separately and then in a combined manner for a blisk of a research compressor without and with aeroelastic coupling.
Centrifugal Pump Performance Enhancement by Blade Shape Modification
Authors: Hassan A. Farid Ayad , Abdalla H. M. , Aly A. Abou El-Azm
Published: August 2017

The effect of impeller blades shape modification on the centrifugal pump performance has been investigated numerically. Impeller blades’ shape have been modified by new technique called “bladelet”. This technique has been called the “bladelet” after the name of the aeroplane winglet because of the great similarity between them in shape and function. The shapes of the blade trailing edge greatly affect the performance of the turbomachines. So, the purpose of the blade tilting (bladelet) is to decrease the recirculating flow at the pump trailing edge due to the high pressure difference and enhance the hydraulic performance of the centrifugal pump.

The bladelet technique has two main geometrical parameters: radial position RBL and bladelet inclination angle θBL. 3-D validated numerical simulation model has been carried out using commercial software, ANSYS® CFX, to study the effect of the bladelet technique and its different parameters on the pump performance at different flow rates.

In this study nine cases with different bladelet parameters have been numerically simulated in order to check its effect on the centrifugal pump performance. These nine cases have been chosen by considering the geometrical constrain of the bladelet parameters. The results of these nine cases have been compared with the basic impeller (the same impeller but without bladelet) at the same operating condition in order to discuss the effect of the bladelet parameters variation on the centrifugal pump performance.

It was found that the use of the bladelet technique decrease the pressure difference between the pressure and the suction side at the blade trailing edge. This decrease in pressure difference at the blade trailing edge decreases the flow recirculation at the impeller outlet from pressure side to suction side. Also, bladelet technique improves the hydraulic efficiency at the part-load operating zone. In addition, the bladelet has a regression effect on the pump head for some cases with high inclination angle and low radial position. However, the bladelet technique increases the impeller blades’ overlap.
Gas Turbine Fouling Offshore: Correction Methodology Compressor Efficiency
Authors: Madsen Stian , Bakken Lars E.
Published: August 2017

Gas turbine performance has been analyzed for a fleet of GE LM2500 engines at two Statoil offshore fields in the North Sea. Both generator drive engines and compressor driver engines have been analyzed, covering both the LM2500 base and plus configurations, as well as the SAC and DLE combustor configurations. Several of the compressor drive engines are running at peak load (T5.4 control), and the production rate is thus limited to the available power from these engines. The majority of the engines discussed run continuously without redundancy, implying that gas turbine uptime is critical for the field’s production and economy.

Previous studies and operational experience have emphasized that the two key factors to minimize compressor fouling are the optimum designs of the inlet air filtration system and the water wash system. An optimized inlet air filtration system, in combination with daily online water wash (at high water-to-air ratio), are the key factors to achieve successful operation at longer intervals between offline washes and higher average engine performance. Operational experience has documented that the main gas turbine recoverable deterioration is linked to the compressor section.

The main performance parameter when monitoring compressor fouling is the gas turbine compressor efficiency. Previous studies have indicated that inlet depression (air mass flow at compressor inlet) is a better parameter when monitoring compressor fouling, whereas instrumentation for inlet depression is very seldom implemented on offshore gas turbine applications. The main challenge when analyzing compressor efficiency (uncorrected) is the large variation in efficiency during the periods between offline washes, mainly due to operation at various engine loads and ambient conditions.

Understanding the gas turbine performance deterioration is of vital importance. Trending of the deviation from the engine baseline facilitates load-independent monitoring of the gas turbine’s condition. Instrument resolution and repeatability are key factors for attaining reliable results in the performance analysis. A correction methodology for compressor efficiency has been developed, which improves the long term trend data for effective diagnostics of compressor degradation. Avenues for further research and development are proposed in order to further increase the understanding of the deterioration mechanisms, as well as gas turbine performance and response.
Development of a 350kW Marine Organic Rankine Power Module for Ship Waste Steam
Authors: Sellers Chris , Hawkins Larry
Published: August 2017

Growing world trade, stiffening emissions requirements, and rising fuel prices are driving the marine industry to improve fuel utilization in large vessels. Exhaust steam boilers are a popular means of capturing energy from ship engine exhaust. The steam is used in various systems around the ship from laundry services to the fresh water generator. However, in most cases the supply outstrips the demand, and energy from un-used steam is dumped into the ocean.

Calnetix Technologies is developing a marine based Organic Rankine Cycle (ORC) designed to produce 350 kW gross power from un-used ship steam. The ORC will operate with sat urated steam at 8 Bar G and 175 °C and cooling sea water at 25 °C. The additional power will be used to offset the fuel demand from onboard diesel generators. This results in a significant fuel savings as well as lowered emissions.

The ORC is comprised of a closed loop system with R245fa refrigerant as the working fluid. A pump is used to move the working fluid around the loop and increase its pressure into the evaporator. The high pressure refrigerant is vaporized using heat from the ship’s steam. The refrigerant then passes through a radial turbine where work is extracted and converted into electricity. Low pressure refrigerant is cooled and condensed by sea water, and then pumped back around the loop.

This paper will focus on the design of the ORC’s integrated power module which is comprised of a high speed radial turbine, variable speed motor/generator, active magnetic bearings, and backup bearings. A high frequency, bidirectional inverter is used to operate the radial turbine at high speed (25,000 RPM.) This allows the turbine to reach an isentropic efficiency of 0.88. The PM bias active magnetic bearing system allows the turbine/rotor combination to operate without the need for lubricating oil and with minimal friction. This reduces the required maintenance and drastically improves the life span of the unit compared to using conventional bearings.

An over-hung turbine design was chosen due to the high operating temperatures of the cycle. Cooling of the stator will be accomplished using a cooling water jacket. Cooling of the rotor will be accomplished by a cooled gas stream generated from a throttling process of the IPM inlet fluid and heat rejection via a heat exchanger.

Various analyses will be presented including calculation of the turbine isentropic efficiency, rotor/stator thermal analysis, component stress analysis, and linear system dynamics for the rotor and magnetic bearing system.
SPH Simulation of an Air-Assisted Atomizer Operating at High Pressure: Influence of Non-Newtonian Effects
Authors: Chaussonnet G. , Koch R. , Bauer H.-J. , Sänger A. , Jakobs T. , Kolb T.
Published: August 2017

A twin-fluid atomizer configuration is predicted by means of the 2D weakly-compressible Smooth Particle Hydrodynamics (SPH) method and compared to experiments. The setup consists of an axial liquid jet fragmented by a co-flowing high-speed air stream (Ug ≈ 60 m/s) in a pressurized atmosphere up to 11 bar (abs.). Two types of liquid are investigated: a viscous Newtonian liquid (μl = 200 mPas) obtained with a glycerol/water mixture and a viscous non-Newtonian liquid (μl, apparent. ≈ 150 mPas) obtained with a carboxymethyl cellulose (CMC) solution. 3D effects are taken into account in the 2D code by introducing (i) a surface tension term, (ii) a cylindrical viscosity operator and (iii) a modified velocity accounting for the divergence of the volume in the radial direction. The numerical results at high pressure show a good qualitative agreement with experiment, i.e. a correct transition of the atomization regimes with regard to the pressure, and similar dynamics and length scales of the generated ligaments. The predicted frequency of the Kelvin-Helmholtz instability needs a correction factor of 2 to be globally well recovered with the Newtonian liquid. The simulation of the non-Newtonian liquid at high pressure shows a similar breakup regime with finer droplets compared to Newtonian liquids while the simulation at atmospheric pressure shows an apparent viscosity similar to the experiment.
Prediction of Structural Supports Influence on Rotating Machinery Dynamics
Authors: Moroz Leonid , Romanenko Leonid , Kochurov Roman , Kashtanov Evgen
Published: August 2017

Rotor lifetime and safety primarily depend on the level of rotor vibration. In order to avoid unwanted consequences for the plant due to rotor damage and to meet the highest requirements of design reliability, accurate rotor dynamic predictions are mandatory. Having the correct rotor model is a critical issue in dynamics prediction. Often research activities are focused only on the rotor-bearing system analysis. However, generally, the whole system, which includes the rotor, bearings, casing and structural supports should be considered. Special attention should be paid to the influence of structural supports which reveals when the rotor is supported by ball bearings because of low damping and high bearing stiffness.

The approach presented in this paper allows us to simulate the influence of structural supports on rotor dynamics response and as a result, the full picture of rotor-bearing-support system resonances can be analyzed to avoid potential problems. The methodology is based on support vibrations modal reduction technics. According to the approach, the natural frequencies and their mode shapes should be calculated for the separate support structure applying a three-dimensional finite element model and the relative displacements at bearing location points are measured. Supports’ normalized modal characteristics (modal mass and modal stiffness) for each vibration mode should then be imported in a rotor dynamics algorithm for rotor unbalance response analysis.

The approach allows for simulation of different types of support structures such as bearing pedestals, steel foundations, tabletop-type foundation, frame and pipe supports of arbitrary geometry, and so on. Validation based on the Jeffcott rotor model is presented. The current methodology has been applied to a single-stage compressor’s rotor-bearing-support system which was manufactured and commissioned. The results of the simulations are discussed.
Heat Transfer Investigation on Center Housing Using Genetic Algorithms and Finite Element Method
Authors: Guo Henry , Ahdad Farid , Guo Wei , Yu Huade
Published: August 2017

Center housing is one of the components of turbocharger which has an undesirable event of excessive heat transfer from turbine side and an excessive heat soak back that lead to oil coking under steady-state conditions and engine shut down conditions. Heat transfer investigation on center housing is necessary to evaluate the designs and prevent oil coking. This paper presents an example of using the genetic algorithms combined to the finite element method to investigate the heat transfer conditions of center housing. First, the basic structure and operation principle of genetic algorithms in heat transfer problem is presented. Then, convection boundary conditions including film heat transfer convection coefficients and bulk temperatures are achieved using genetic algorithms combined with finite element method based on existing test data. Final thermal boundary conditions can be used to predict temperature distribution of center housings before testing in similar applications and which can help re-design the water jacket and oil channel as well in the initial design stage.
Experimental and Numerical Investigation of a Circumferential Groove Casing Treatment in a Low Speed Axial Research Compressor at Different Tip Clearances
Authors: Rolfes Matthias , Lange Martin , Vogeler Konrad , Mailach Ronald
Published: August 2017

The demand of increasing pressure ratios for modern high pressure compressors leads to decreasing blade heights in the last stages. As tip clearances cannot be reduced to any amount and minimum values might be necessary for safety reasons, the tip clearance ratios of the last stages can reach values notably higher than current norms. This can be intensified by a compressor running in transient operations where thermal differences can lead to further growing clearances. For decades, the detrimental effects of large clearances on an axial compressor’s operating range and efficiency are known and investigated. The ability of circumferential casing grooves in the rotor casing to improve the compressor’s operating range has also been in the focus of research for many years. Their simplicity and ease of installation are one reason for their continuing popularity nowadays, where advanced methods to increase the operating range of an axial compressor are known.

In a previous paper [1], three different circumferential groove casing treatments were investigated in a single stage environment in the Low Speed Axial Research Compressor at TU Dresden. One of these grooves was able to notably improve the operating range and the efficiency of the single stage compressor at very large rotor tip clearances (5% of chord length). In this paper, the results of tests with this particular groove type in a three stage environment in the Low Speed Axial Research Compressor are presented. Two different rotor tip clearance sizes of 1.2% and 5% of tip chord length were investigated. At the small tip clearance, the grooves are almost neutral. Only small reductions in total pressure ratio and efficiency compared to the solid wall can be observed. If the compressor runs with large tip clearances it notably benefits from the casing grooves. Both, total pressure and efficiency can be improved by the grooves in a similar extent as in single stage tests. Five-hole probe measurements and unsteady wall pressure measurements show the influence of the groove on the flow field. With the help of numerical investigations the different behavior of the grooves at the two tip clearance sizes will be discussed.