bluuebunny/crossref_metadata_2025_split huggingface dataset:
Life Extension of Axial Compressor Disc of a Turbo-Shaft Engine
Authors: Muthu S. Esakki , Selwyn A. , Roy Hardik , Degaonkar Girish K. 
Published: July 2018

The cost of aero engine and its maintenance is going higher day by day, the life of the critical parts and its availability play a major role to keep the fleet in operation. Engine components works under extremely high stress levels so the life of the components is limited. Most of the critical components are retired by the operator before they reach their theoretical life. The uncertainty in accurate life prediction induces the risk which is the cause for premature retirement. Metallurgical study of the life expired components and fatigue/fracture methodologies are used to estimate the residual useful life of the components.
This paper describes the life extension methodology used for an axial compressor disc of turbo-shaft engine. The disc has completed its safe life in the aircraft. The studies are carried out to determine the residual life of the disc to extend the life. Two life completed disc are identified. Specimens are cut from the disc for tensile test and LCF tests. Probable mission cycles for the aircraft are collected and fatigue cycle data are prepared. Finite element based stress analysis is carried out using Ansys software with multi axial loads. Based on the stress analysis, disc bore and pin hole are identified as critical area. The computed stress–strain response is used to predict the fatigue crack initiation life using effective strain range parameters on the critical areas. Fatigue damage for different mission cycles are also calculated using critical plane approach. The plane where crack initiate is called critical plane and it is calculated iteratively based on the nodal stress result. Life for different mission cycle is calculated and minimum life of all the cycle is determined. This calculated life gives the amount of residual life available and the scope for life extension. The disc is tested in cyclic spin test rig to confirm the remaining potential life. The test results are compared with the numerical estimation. It is found that the residual life of the life completed component has got potential life of one more overhaul.
Correlation Between FEA and Testing for HCF-Safety Assessment of an Aero Engine Turbine Rotor Blade
Authors: Khan Reshma , Kamili Owais Majid , Togere Nagabhushana Suresh , Subbaram Shylaja 
Published: July 2018

High Cycle Fatigue (HCF) of turbine blades is one of the major design concerns in an Aero Gas turbine engine developmental program. Resonance induced High Cycle Fatigue (HCF) failure of blades may result in engine catastrophe having expensive consequences leading to program delays and cost overruns in a project. Even though, the resonance regimes in operating envelope can be predicted using FE tools, there are uncertainties involved in theoretical prediction of blade vibratory amplitudes. If these blade amplitudes cross the allowable limits during operation, HCF failures are expected to occur. The purpose of this paper is to assess the safety of the blades from HCF point of view. An integrated approach using test data and analytical model was employed to evaluate the vibratory behavior of a Low Pressure turbine rotor blade of an Aero-Gas Turbine engine. Correlation factors between blade tip amplitudes and dynamic stresses during critical modes of vibration were established using the data from strain gages, Non Intrusive Stress Measurement System (NSMS) and FE Model. Good agreement was found between the predicted stresses using FE/NSMS and measured vibratory stresses from strain gages. Fine tuned FE model was generated for evaluation of vibratory stresses from NSMS data.
Results have shown up to 300% scatter in the dynamic responses across the blades and 2% scatter in natural frequency for a particular resonance. Amplitude–stress relationship shows linearity and is observed to be invariant across the blades. All these statistical variations in responses along-with established correlation factors were considered for the safety assessment of blades from HCF point of view.
Enhancing Gas Turbine Operation With Heavy Fuel Oil
Authors: Muralidharan Vikram , Vierling Matthieu 
Published: July 2018

Power generation in south Asia has witnessed a steep fall due to the shortage of natural gas supplies for power plants and poor water storage in reservoirs for low hydro power generation. Due to the current economic scenario, there is worldwide pressure to secure and make more gas and oil available to support global power needs. With constrained fuel sources and increasing environmental focus, the quest for higher efficiency would be imminent.
Natural gas combined cycle plants operate at a very high efficiency, increasing the demand for gas. At the same time, countries may continue to look for alternate fuels such as coal and liquid fuels, including crude and residual oil, to increase energy stability and security.
In over the past few decades, the technology for refining crude oil has gone through a significant transformation. With the advanced refining process, there are additional lighter distillates produced from crude that could significantly change the quality of residual oil used for producing heavy fuel.
Using poor quality residual fuel in a gas turbine to generate power could have many challenges with regards to availability and efficiency of a gas turbine. The fuel needs to be treated prior to combustion and needs a frequent turbine cleaning to recover the lost performance due to fouling.
This paper will discuss GE’s recently developed gas turbine features, including automatic water wash, smart cooldown and model based control (MBC) firing temperature control. These features could significantly increase availability and improve the average performance of heavy fuel oil (HFO). The duration of the gas turbine offline water wash sequence and the rate of output degradation due to fouling can be considerably reduced.
Experimental Study on the Stability and Thermophysical Properties of Binary Propanol-Water Mixtures Based Phase Change Microencapsule Suspensions
Authors: Wang Liang , Liu Li , Wang Yifei , Chai Lei , Yang Zheng , Chen Haisheng , Tan Chunqing 
Published: July 2018

Phase change microencapsules are the microsized particles made of phase change materials (paraffin wax ect.) sealed by the thin shell (polymer ect.) via the methods of microencapsulation. During last decade, due to the large amount of melting/solidifying heat, much attention have been paid on their application in environmental control, building, textiles and electronics ect. Also the novel thermal fluids by phase change microencapsules suspending in the traditional thermal fluids have shown their superior heat storage density and convective heat transfer performance, which can behave as heat storage media and heat transfer media simultaneously. However, the density difference between the phase change microencapsules and tranditional unitary fluid would lead to the unstable suspending states which seriously affect the heat storage and heat transfer performance.
Binary mixtures such as alcohol-water etc have already played the important roles in the heat transfer equipments. In this paper, binary propanol-water mixtures of various proportion were formulated as the base fluids, and their stabilities were studied. The result shows that binary propanol-water mixtures with the desity of 941kg/m3 showed the best stability and no stratification was found after standing for 48 hours.
The morphology and diameter distribution of the microencapsule particles were tested by the scanning electron microscope (SEM) and Malvern Nanosizer respectively, and the result show that the diameter of the particles is in the range of 10–80μm with the average value of 26.4μm. The phase change enthalpy and the effective heat capacity of phase change microencapsule suspensions with the concentration of 10–40wt% were measured by the differencial scanning calorimeter (DSC) and it was found the phase change enthalpy of the phase change microencapsule is 152.8J/g and the undercooling is only 7.3°C. The effect of concentration and temperature on the rheological behavior and viscosities of suspensions were experimentally studied by the TA DHR-G2 rheometer. The result shows that the suspensions behave as Newtonian fluids even when the concentration is as high as 40wt% and the viscosities fit well with Vand model. By the Hot Disk 2500S thermal constant analyzer (Sweden), the thermal conductivities of 0–40wt% suspensions were tested at 20–70°C and the variation was analyzed further. The concentration and expansion of MPCM particles during the phase change period were found to affect the thermal expansion coefficient of the MPCM suspensions obviously. The above experimental result and analyzation of stability and thermophysical properties will provide a complete and important data for the application in heat storage and heat transfer.
A Method for Predicting Six Degrees-of-Freedom Ultimate Limit State of Subsea Mudmats
Authors: Feng Xiaowei , Gourvenec Susan 
Published: July 2018

Rectangular mudmat foundations are extensively deployed in deep waters to support subsea infrastructure leading to renewed interest in optimizing the design of offshore shallow foundations. Offshore industry guidelines (e.g. API RP2GEO and ISO 19901-4) are based on classical bearing capacity theory of a plane strain strip foundation resting on the surface of a uniform Tresca material. More realistic conditions are accounted for through a range of superposed empirical modification factors and the effective width principle.
In practice, subsea foundations experience complex loading in six degrees-of-freedom (vertical load, biaxial horizontal load, biaxial moment and torsion), due to expansion and contraction of connected pipelines and jumpers; they may be able to mobilize transient tensile capacity; and they are typically three-dimensional in plan, shallowly embedded and founded on soft, normally consolidated, soils with linearly increasing strength with depth. Accurate determination of the ultimate limit state of subsea mudmats is best achieved by considering the relevant foundation, soil and loading boundary conditions explicitly.
In this paper, a simplified approach for predicting the ultimate limit state of mudmat foundations under six degrees-of-freedom, based on failure envelopes, obtained from extensive finite element analyses, is compared with the traditional bearing capacity methods as recommended in industry guidelines.
Sustained Uplift of Skirted Foundation in Clay
Authors: Li Xiaojun , Tian Yinghui , Cassidy Mark J. , Gaudin Christophe 
Published: July 2018

A series of centrifuge tests have been performed to investigate the uplift behaviour of a shallow skirted foundation resting on clay subjected to various sustained loadings expressed as a fraction of the undrained bearing capacity in compression. Displacements, uplift loads, total and pore pressures underneath the foundation were monitored during testing to provide insight on the development of negative pore pressure (suction) at the foundation base and on the mechanism triggering breakout. The results indicate that the displacement rate and the time the uplift load can be sustained depend on the magnitude of the load, but also on the time the foundation experienced consolidation prior to uplift. Breakout was not observed at a relatively large time scale under low sustained loadings, while the foundation was pulled out directly under high loading levels. At intermediate loadings, breakout was inferred from the sudden increase in displacement rate. The breakout mechanism of the foundation is also discussed based on the observation of pore pressure variations underneath the foundation.
The outcomes of the present study have the potential to provide a better understanding of the suction mechanism for offshore foundations and to provide guidelines for offshore retrieval operations.
Evaluation of Plate Anchors Capacity in Saturated Soils Using Different Constitutive Models
Authors: Aghazadeh Zahra , Rahman M. S. , Gabr M. A. 
Published: July 2018

Evaluation of the uplift capacity of plate anchors in saturated clay is an important aspect in offshore anchoring of various structures. In most of the literature reviewed, a constitutive model such as Tresca or Mohr-Coulomb has been used in analyses. There exists a need to study the anchors’ pull out capacity using other advanced soil models and discern differences in results.
This study presents the results of finite element simulation of a rectangular or circular plate anchor in saturated clay. The capacity factors (Nc) of the plate are assessed through the application of displacement control approach and the results are compared to the lower bound solution as well as to data obtained from similar studies available in the literature.
In addition to Mohr-Coulomb model, two other constitutive models are used to represent the soil deformation. These are Modified Cam-Clay, and Soft Soil models. Undrained effective stress analyses are conducted using the computer program PLAXIS. A series of analyses using different embedment depths are performed for all three constitutive models. Results as Nq value from the three constitutive models are presented and discussed.
A Genome-Wide Screen of Deletion Mutants in the Filamentous Saccharomyces cerevisiae Background Identifies Ergosterol as a Direct Trigger of Macrophage Pyroptosis
Authors: Koselny Kristy , Mutlu Nebibe , Minard Annabel Y. , Kumar Anuj , Krysan Damian J. , Wellington Melanie 
Published: July 2018

ABSTRACT

Phagocytic cells such as macrophages play an important role in the host defense mechanisms mounted in response to the common human fungal pathogen
Candida albicans
.
In vitro
,
C. albicans
triggers macrophage NLRP3-
Casp1/11
-mediated pyroptosis, an inflammatory programmed cell death pathway. Here, we provide evidence that
Casp1/11
-dependent pyroptosis occurs in the kidney of infected mice during the early stages of infection. We have also used a genome-wide screen of nonessential Σ1278b
Saccharomyces cerevisiae
genes to identify genes required for yeast-triggered macrophage pyroptosis. The set of genes identified by this screen was enriched for those with functions in lipid and sterol homeostasis and trafficking. These observations led us to discover that cell surface localization and/or total levels of ergosterol correlate with the ability of
S. cerevisiae
,
C. albicans
, and
Cryptococcus neoformans
to trigger pyroptosis. Since the mammalian sterol cholesterol triggers NLRP3-mediated pyroptosis, we hypothesized that ergosterol may also do so. Consistent with that hypothesis, ergosterol-containing liposomes but not ergosterol-free liposomes induce pyroptosis. Cell wall mannoproteins directly bind ergosterol, and we found that Dan1, an ergosterol receptor mannoprotein, as well as specific mannosyltransferases, is required for pyroptosis, suggesting that cell wall-associated ergosterol may mediate the process. Taken together, these data indicate that ergosterol, like mammalian cholesterol, plays a direct role in yeast-mediated pyroptosis.

IMPORTANCE
Innate immune cells such as macrophages are key components of the host response to the human fungal pathogen
Candida albicans
. Macrophages undergo pyroptosis, an inflammatory, programmed cell death, in response to some species of pathogenic yeast. Prior to the work described in this report, yeast-triggered pyroptosis has been observed only
in vitro
; here, we show that pyroptosis occurs in the initial stages of murine kidney infection, suggesting that it plays an important role in the initial response of the innate immune system to invasive yeast infection. We also show that a key component of the fungal plasma membrane, ergosterol, directly triggers pyroptosis. Ergosterol is also present in the fungal cell wall, most likely associated with mannoproteins, and is increased in hyphal cells compared to yeast cells. Our data indicate that specific mannoproteins are required for pyroptosis. This is consistent with a potential mechanism whereby ergosterol present in the outer mannoprotein layer of the cell wall is accessible to the macrophage-mediated process. Taken together, our data provide the first evidence that ergosterol plays a direct role in the host-pathogen interactions of fungi.
New Tools for Syphilis Research
Authors: Lukehart Sheila A. 
Published: July 2018

Syphilis research has been severely limited by the necessity to propagate
Treponema pallidum
in vivo
in rabbits. After decades of erroneous or irreproducible reports of cultivation of
T. pallidum
, the recent very convincing report of its successful long-term
in vitro
propagation opens numerous opportunities for development of genetic tools for studying pathogenesis and protein function, antigenic variation, and surface exposure of antigens.
Similarities and differences in the associations between patient safety culture dimensions and self-reported outcomes in two different cultural settings: a national cross-sectional study in Palestinian and Belgian hospitals
Authors: Najjar Shahenaz , Baillien Elfi , Vanhaecht Kris , Hamdan Motasem , Euwema Martin , Vleugels Arthur , Sermeus Walter , Schrooten Ward , Hellings Johan , Vlayen Annemie 
Published: July 2018

ObjectivesTo investigate the relationships between patient safety culture (PSC) dimensions and PSC self-reported outcomes across different cultures and to gain insights in cultural differences regarding PSC.DesignObservational, cross-sectional study.SettingNinety Belgian hospitals and 13 Palestinian hospitals.ParticipantsA total of 2836 healthcare professionals matched for profession, tenure and working hours.Primary and secondary outcome measuresThe validated versions of the Belgian and Palestinian Hospital Survey on Patient Safety Culture were used. An exploratory factor analysis was conducted. Reliability was tested using Cronbach’s alpha (α). In this study, we examined the specific predictive value of the PSC dimensions and its self-reported outcome measures across different cultures and countries. Hierarchical regression and bivariate analyses were performed.ResultsEight PSC dimensions and four PSC self-reported outcomes were distinguished in both countries. Cronbach’s α was α≥0.60. Significant correlations were found between PSC dimensions and its self-reported outcome (p value range <0.05 to <0.001). Hierarchical regression analyses showed overall perception of safety was highly predicted by hospital management support in Palestine (β=0.16, p<0.001) and staffing in Belgium (β=0.24, p<0.001). The frequency of events was largely predicted by feedback and communication in both countries (Palestine: β=0.24, p<0.001; Belgium: β=0.35, p<0.001). Overall grade for patient safety was predicted by organisational learning in Palestine (β=0.19, p<0.001) and staffing in Belgium (β=0.19, p<0.001). Number of events reported was predicted by staffing in Palestine (β=−0.20, p<0.001) and feedback and communication in Belgium (β=0.11, p<0.01).ConclusionTo promote patient safety in Palestine and Belgium, staffing and communication regarding errors should be improved in both countries. Initiatives to improve hospital management support and establish constructive learning systems would be especially beneficial for patient safety in Palestine. Future research should address the association between safety culture and hard patient safety measures such as patient outcomes.
Prognostic value of chronic total occlusions detected on coronary computed tomographic angiography
Authors: Opolski Maksymilian P , Gransar Heidi , Lu Yao , Achenbach Stephan , Al-Mallah Mouaz H , Andreini Daniele , Bax Jeroen J , Berman Daniel S , Budoff Matthew J , Cademartiri Filippo , Callister Tracy Q , Chang Hyuk-Jae , Chinnaiyan Kavitha , Chow Benjamin JW , Cury Ricardo C , DeLago Augustin , Feuchtner Gudrun M , Hadamitzky Martin , Hausleiter Joerg , Kaufmann Philipp A , Kim Yong-Jin , Leipsic Jonathon A , Maffei Erica C , Marques Hugo , Pontone Gianluca , Raff Gilbert , Rubinshtein Ronen , Shaw Leslee J , Villines Todd C , Gomez Millie , Jones Erica C , Peña Jessica M , Min James K , Lin Fay Y 
Published: July 2018

ObjectiveData describing clinical relevance of chronic total occlusion (CTO) identified by coronary CT angiography (CCTA) have not been reported to date. We investigated the prognosis of CTO on CCTA.MethodsWe identified 22 828 patients without prior known coronary artery disease (CAD), who were followed for a median of 26 months. Based on CCTA, coronary lesions were graded as normal (no atherosclerosis), non-obstructive (1%–49%), moderate-to-severe (50%–99%) or totally occluded (100%). All-cause mortality, and major adverse cardiac events defined as mortality, non-fatal myocardial infarction and late coronary revascularisation (≥90 days after CCTA) were assessed.ResultsThe distribution of patients with normal coronaries, non-obstructive CAD, moderate-to-severe CAD and CTO was 10 034 (44%), 7965 (34.9%), 4598 (20.1%) and 231 (1%), respectively. The mortality rate per 1000 person-years of CTO patients was non-significantly different from patients with moderate-to-severe CAD (22.95; 95% CI 12.71 to 41.45 vs 14.46; 95% CI 12.34 to 16.94; p=0.163), and significantly higher than of those with normal coronaries and non-obstructive CAD (p<0.001 for both). Among 14 382 individuals with follow-up for the composite end point, patients with CTO had a higher rate of events than those with moderate-to-severe CAD (106.56; 95% CI 76.51 to 148.42 vs 65.45; 95% CI 58.01 to 73.84, p=0.009). This difference was primarily driven by an increase in late revascularisations in CTO patients (27 of 35 events). After multivariable adjustment, compared with individuals with normal coronaries, the presence of CTO conferred the highest risk for adverse cardiac events (14.54; 95% CI 9.11 to 23.20, p<0.001).ConclusionsThe detection of CTO on non-invasive CCTA is associated with increased rate of late revascularisation but similar 2-year mortality as compared with moderate-to-severe CAD.Trial registration numberNCT01443637.