796 research outputs found

    Sector Mode Assembling Reduction Technique for High-Fidelity Blisk Models with Geometry Mistuning

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    Blade mistuning in blisks arises primarily from the scatters of blade geometry profiles caused by manufacturing tolerance, in-service wear, blade repairs, etc. There is a recent trend to capture the blade-to-blade geometry variances through precise geometry measurements by a 3D optical scanning system in order to obtain an improved blade geometric mistuning evaluation capability. However, this usually leads to prohibitive computational costs due to the large-scale, high-fidelity industrial blisk finite element models. This paper develops an original model reduction approach, Sector Mode Assembling Reduction Technique (SMART), specifically for the high-fidelity blisk model fully mistuned by blade geometric variances, with either topologically compatible or incompatible blade meshes. The basic idea of SMART is to construct the sector-level reduction mode basis by strategically assembling the truncated cyclic modes independently computed for each “isolated” sector with assumed cyclic symmetry at the sector interfaces. Benefiting from the block structure of the SMART mode basis, the reduced-order models are derived by a series of sector-level projections with a relatively low memory requirement and computational cost. Another hidden benefit is that the SMART approach enables efficient structural modification predictions of the global blisk modes because only the modes of the sectors undergoing blade modification need to be re-evaluated and replaced in the SMART mode basis. The SMART approach is applied into a high-fidelity “as-measured model” of a blended blisk, constructed upon the geometry measurement by the state-of-the-art 3D optical scanning technology. It is fully demonstrated that the reduced-order model derived by SMART, featured by a minimal size, is able to reproduce the dynamics of the full-order as-measured blisk model with high accuracy

    Blisk With Small Geometry Mistuning and Blend Repair: As-Measured Finite Element Model and Experimental Verification

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    This paper presents an “As-Measured Model” (AMM) of a blended blisk, built upon the measurement of the true geometry of the blisk by the three-dimensional optical scanning technology. This high-fidelity model aims to account for the variances of blade frequencies and mode shapes within the real blisk in the presence of both the blend repair and inherent geometry mistuning due to manufacturing, etc. An improved mesh updating strategy is proposed to adapt a seed blisk finite element model (FEM) to the measured geometry. The resultant AMM is therefore able to accurately represent the measured blade-to-blade geometry variances. The classical blade detuning test (BDT) in combination with a novel “correction” procedure is employed to experimentally evaluate the “blade-alone” frequency mistuning pattern in the real blisk. Experimental verification of the AMM demonstrates that it is able to not only capture the blade-alone frequency and mode shape variations due to both the blend and intrinsic blade geometry variances, but also to reproduce the global dynamics of the blended blisk with acceptable accuracy

    Experimental Joint Identification Using System Equivalent Model Mixing in a Bladed-Disk

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    A joint between two components can be seen as a means to transmit dynamic information from one side to the other. To identify the joint, a reverse process called decoupling can be applied. This is not as straightforward as the coupling, especially when the substructures have three-dimensional characteristics or sensor mounting effects are significant or the interface degrees-of-freedom (DOF) are inaccessible for response measurement and excitation. Acquiring frequency response functions (FRFs) at the interface DOF, therefore, becomes challenging. Consequently, one has to consider hybrid or expansion methods that can expand the observed dynamics on accessible DOF to inaccessible DOF. In this work, we attempt to identify the joint dynamics using the System Equivalent Model Mixing (SEMM) decoupling method with a virtual point description of the interface. Measurements are made only at the internal DOF of the uncoupled substructures and also of the coupled structure assuming that the joint dynamics are observable in the assembled state. Expanding them to the interface DOF and performing coupling and decoupling operations iteratively, the joint is identified. The substructures under consideration are a disk and blade - an academic test geometry which has a total of 18 blades but only one blade-to-disk joint is considered in this investigation. The joint is a typical dove-tail assembly. The method is shown to identify the joint without any direct interface DOF measurement

    Effects of American Ginseng on Preimplantation Development and Pregnancy in Mice.

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    In North America, a high proportion of pregnant women use herbal medications including North American ginseng. This medicinal plant contains high amounts of triterpene saponins (ginsenosides), which are the main bioactive compounds. It is important to assess ginseng\u27s impact on all reproductive functions to ensure the safety of pregnant women and fetuses. In this study, we defined the concentration-responsive effects of North American alcoholic and aqueous ginseng extracts on preimplantation development in vitro and on pregnancy and post-partum development in the mouse. Two-cell mouse embryos were cultured with 5 different concentrations of whole ginseng root extracts, or ginsenosides Rb1, Rg1 and Re alone, a combinatorial ginsenoside solution and a crude polysaccharide fraction solution. Embryonic development and recovery from each treatment was assessed. To investigate the in vivo effects of ginseng extracts, female mice were gavaged with 50[Formula: see text]mg/kg/day, 500[Formula: see text]mg/kg/day or 2000[Formula: see text]mg/kg/day of either extract (treatment) or water (sham) for 2 weeks prior to mating and throughout gestation. Gestation period, litter size, pup growth and pup sex ratio were evaluated. Oral ginseng consumption did not significantly affect fertility or pregnancy in the mouse. High doses of ginseng (2000[Formula: see text]mg/kg/day) decreased maternal weight gain. Direct treatment of preimplantation embryos in vitro demonstrated that ALC and AQ extract treatment reduced development in a concentration responsive manner, while only ALC extract effects were largely reversible. Treatments with individual or combinatorial ginsenosides, or the polysaccharide fraction solution alone did not impair preimplantation development, in vitro. In conclusion, maternal oral consumption of ginseng has little negative impact on pregnancy in the mouse, however, direct exposure to ginseng extract during mouse preimplantation development in vitro is detrimental

    Bioenergy II: Characterization of the Pesticide Properties of Tobacco Bio-Oil

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    Pyrolysis converts biomass such as agricultural and forestry waste into bio-oil, preserving some chemicals while creating other, new ones. Nicotine, a chemical present in tobacco leaves and a known pesticide, was found to remain intact during pyrolysis. As expected, insecticidal properties were observed for tobacco bio-oil. Pesticide characteristics of tobacco bio-oil have been observed on the Colorado potato beetle (CPB), a pest currently resistant to all major insecticides, as well as a few bacteria and fungi that do not currently respond well to chemical treatment. Unexpectedly, nicotine-free fractions of the bio-oil were also found to be highly lethal to the beetles and successful at inhibiting the growth of select microorganisms. Through GC-MS, it was found that the active, nicotine-free fractions were rich in phenolics, chemicals likely created from lignin during pyrolysis. While bio-oils in general are known to contain phenolic chemicals, such as cresols, to our best knowledge, quantitative analysis has not been performed to determine if these chemicals are solely responsible for the observed pesticide activities. Based on GC-MS results, ten of the most abundant chemicals, eight of which were phenolic chemicals, were identified and examined through bio-assays. A mixture of these chemicals at the concentration levels found in the bio-oil did not account for the bio-oil activity towards the microorganisms. Tobacco bio-oil may have potential as a pesticide, however, further analyses using liquid chromatography is necessary to identify the remaining active chemicals

    Merkel-cell carcinoma: ESMO-EURACAN Clinical Practice Guideline for diagnosis, treatment and follow-up

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    : ‱ This ESMO Clinical Practice Guideline provides key recommendations for managing Merkel-cell carcinoma (MCC). ‱ Recommendations are based on available scientific data and the multidisciplinary group of experts’ collective opinion. ‱ The guideline covers clinical and pathological diagnosis, staging and risk assessment, treatment and follow-up. ‱ Algorithms for the management of locoregional and inoperable/metastatic disease are provided. ‱ A multidisciplinary team with a high level of expertise in MCC should diagnose and make decisions about therapy

    Correction to: Human behavior and Homo-mammal interactions at the first European peopling: new evidence from the Pirro Nord site (Apricena, Southern Italy)

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    In the original publication of this article, one of the author names was incorrectly captured. The first name should be Razika, then family name should be Chelli–Cheheb

    Paclitaxel, vinorelbine and 5-fluorouracil in breast cancer patients pretreated with adjuvant anthracyclines

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    We investigated the activity and toxicity of a combination of vinorelbine (VNB), paclitaxel (PTX) and 5-fluorouracil (5-FU) continuous infusion administered as first-line chemotherapy in metastatic breast cancer patients pretreated with adjuvant anthracyclines. A total of 61 patients received a regimen consisting of VNB 25 mg m−2 on days 1 and 15, PTX 60 mg m−2 on days 1, 8 and 15 and continuous infusion of 5-FU at 200 mg m−2 every day. Cycles were repeated every 28 days. Disease response was evaluated by both RECIST and World Health Organization (WHO) criteria. Objective responses were recorded in 39 of 61 patients (64.0%) assessed by WHO and in 36 of 50 patients (72.0%) assessable by RECIST criteria. Complete remission occurred in 15 (24.6%) and 14 patients (28.0%), respectively. The median time to progression and overall survival of entire population was 10.6 and 27.3 months, respectively, and median duration of complete response was 14.8 months. The dose-limiting toxicity was myelosuppression (leucopenia grade 3/4 in 52.5% of patients). Grade 3/4 nonhaematologic toxicities included mucositis/diarrhoea in 13.1%, skin in 3.3% and cardiac in 1.6% of patients. Grade 2/3 neurotoxicity was observed in five patients (7.2%). The VNB, PTX and 5-FU continuous infusion combination regimen was active and manageable. Complete responses were frequent and durable

    Prognostic factors in stage III-IV adrenocortical carcinomas (ACC): an European Network for the Study of Adrenal Tumor (ENSAT) study.

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    BACKGROUND: The clinical course of advanced adrenocortical carcinoma (ACC) is heterogeneous. Our study aimed primarily to refine and make headway in the prognostic stratification of advanced ACC. PATIENTS AND METHODS: Patients with advanced ENSAT ACC (stage III or stage IV) at diagnosis registered between 2000 and 2009 in the ENSAT database were enrolled. The primary end point was overall survival (OS). Parameters of potential prognostic relevance were selected. Univariate and multivariate analyses were carried out: model 1 'before surgery'; model 2 'post-surgery'. RESULTS: Four hundred and forty-four patients with advanced ENSAT ACC (stage III: 210; stage IV: 234) were analyzed. After a median follow-up of 55.2 months, the median OS was 24 months. A modified ENSAT (mENSAT) classification was validated: stage III (invasion of surrounding tissues/organs or the vena renalis/cava) and stage IVa, IVb, IVc (2, 3 or >3 metastatic organs, including N, respectively). Two- or 5-year OS was 73%, 46%, 26% and 15% or 50%, 15%, 14% and 2% for stages III, IVa, IVb and IVc, respectively. In the multivariate analysis, mENSAT stages (stages IVa, IVb, or IVc, respectively) were significantly correlated with OS (P 6 and/or Ki67 ≄20%, P = 0.06) in model 2. CONCLUSION: The mENSAT classification and GRAS parameters (Grade, R status, Age and Symptoms) were found to best stratify the prognosis of patients with advanced ACC
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