6,607 research outputs found
Uncertainty quantification of leakages in a multistage simulation and comparison with experiments
The present paper presents a numerical study of the impact of tip gap uncertainties in a multistage turbine. It is well known that the rotor gap can change the gas turbine efficiency but the impact of the random variation of the clearance height has not been investigated before. In this paper the radial seals clearance of a datum shroud geometry, representative of steam turbine industrial practice, was systematically varied and numerically tested. By using a Non-Intrusive Uncertainty Quantification simulation based on a Sparse Arbitrary Moment Based Approach, it is possible to predict the radial distribution of uncertainty in stagnation pressure and yaw angle at the exit of the turbine blades. This work shows that the impact of gap uncertainties propagates radially from the tip towards the hub of the turbine and the complete span is affected by a variation of the rotor tip gap. This amplification of the uncertainty is mainly due to the low aspect ratio of the turbine and a similar behavior is expected in high pressure turbines
Increased levels of RNA oxidation enhance the reversion frequency in aging pro-apoptotic yeast mutants
Despite recent advances in understanding the complexity of RNA processes, regulation of the metabolism of oxidized cellular RNAs and the mechanisms through which oxidized ribonucleotides affect mRNA translation, and consequently cell viability, are not well characterized. We show here that the level of oxidized RNAs is markedly increased in a yeast decapping Kllsm4Δ1 mutant, which accumulates mRNAs, ages much faster that the wild type strain and undergoes regulated-cell-death. We also found that in Kllsm4Δ1 cells the mutation rate increases during chronological life span indicating that the capacity to han- dle oxidized RNAs in yeast declines with aging. Lowering intracellular ROS levels by antioxidants recovers the wild- type phenotype of mutant cells, including reduced amount of oxidized RNAs and lower mutation rate. Since mRNA oxidation was reported to occur in different neurodegen- erative diseases, decapping-deficient cells may represent a useful tool for deciphering molecular mechanisms of cell response to such conditions, providing new insights into RNA modification-based pathogenesis
Applied linguistics as a manifestation of exo-, meso- and endo-symbiosis
An assumption is made that applied linguistics may be viewed as an outcome of an interplay of a dichotomy of endogenous and exogenous symbionts, mediated by important mesogenous symbionts acting jointly within the domain of language and communication. All of them form a system of bifurcations which may generally be called ‘a flow tool-language design’ or The Bifurcational Model of Symbiosis (BiMoS). In this model, bifurcations form a ‘grammar of bifurcations’ whose power is symbiotic in the overall functioning of language. Furthermore, the occurrence of the above mentioned types of symbionts on the language side allows for a division of ‘linguolabourese’ (or the whole ‘life of language’ as opposed to ‘instrumentolabourese’, or the whole ‘life of tools’) into three more or less distinct and interconnected areas of symbiosis: the exogenous area, the mesogenous area, and the endogenous area, respectively. The afore mentioned areas further justify a division of linguistics into three respective types: exogenous (exo-) linguistics, mesogenous (meso-) linguistics, and endogenous (endo-) linguistics. Their subdomains of interest vary but are highly interconnected, blended and synergistic. Applied linguistics is viewed here as belonging predominantly to (or taking theoretical and practical interest in) the mesogenous and endogenous areas of linguolabourese, though it is strongly supported by the underlying exogenous area.An assumption is made that applied linguistics may be viewed as an outcome of an interplay of a dichotomy of endogenous and exogenous symbionts, mediated by important mesogenous symbionts acting jointly within the domain of language and communication. All of them form a system of bifurcations which may generally be called ‘a flow tool-language design’ or The Bifurcational Model of Symbiosis (BiMoS). In this model, bifurcations form a ‘grammar of bifurcations’ whose power is symbiotic in the overall functioning of language. Furthermore, the occurrence of the above mentioned types of symbionts on the language side allows for a division of ‘linguolabourese’ (or the whole ‘life of language’ as opposed to ‘instrumentolabourese’, or the whole ‘life of tools’) into three more or less distinct and interconnected areas of symbiosis: the exogenous area, the mesogenous area, and the endogenous area, respectively. The afore mentioned areas further justify a division of linguistics into three respective types: exogenous (exo-) linguistics, mesogenous (meso-) linguistics, and endogenous (endo-) linguistics. Their subdomains of interest vary but are highly interconnected, blended and synergistic. Applied linguistics is viewed here as belonging predominantly to (or taking theoretical and practical interest in) the mesogenous and endogenous areas of linguolabourese, though it is strongly supported by the underlying exogenous area
A Proposal for an Environmental Decision Support System at the Regional Level: Concepts, Support Methodology, Tools and their Terminology
One of the goals of IIASA's research activities in the area of environmental quality modeling is the integration of data and models in a unified framework to assist decision makers with the management of complex environmental systems.
Building on IIASA's work undertaken within the WELMM (Water, Energy, Land, Materials and Manpower) project of the former Resources and Environment Area and the work on Decision Support Systems of the former Management and Technology Area, a conceptual framework for an environmental decision support system (EDSS) has been developed and is presented in this paper. The proposed EDSS has been developed with the interest and the financial support of the CSI, the Center for Information Systems of the Regional Government of Piemonte, Italy.
The main issue addressed by this paper is to devise a system assisting decision makers in tackling environmental problems at the regional level. These decisions are typically characterized by a combination of both structured (formalizable, described in a quantitative model) and unstructured elements (incomplete information, undefined cause-effect relationships, influence of political objectives, public perception, consideration of aesthetics, etc.).
The proposed EDSS enables the user to use models and data, of relevance to a particular task, which are embedded in the EDSS in the form of a process information system. The specific feature of this process information system is that it contains processes of anthropogenic nature (the socio-economic activities being the cause of environmental impacts like power plants, industrial production units, etc.) as well as natural processes determining the spatial/temporal distribution and the extent of environmental quality changes (like the dispersion and deposition of air pollutants and their effect on human population, vegetation and wildlife).
The system ensures that the data and models, which have been developed in the context of specific EDSS applications are documented right from the outset and become thus equally available for further use. This becomes especially important in view of the long-term effort to be put into the development of data and models dealing with the large number of environmental problems that governments, industry and academic institutions are confronted with at the regional level
Structural aspects of the female sexual differentiation of the pirarucu (Arapaima gigas, SCHINZ, 1822).
The pirarucu (Arapaima gigas) are the biggest scale Amazonian fish and their farming potential is enormous. However, there are few studies involving the reproductive physiology of pirarucu. Raising fish in confined environments still encounters several adversities, being necessary basic studies for the development of the productive chain, mainly at the early stages of development. Thus, studies related to the gonadal development are essential for the understanding of the reproductive biology of the species
comparison of breast muscle traits and meat quality characteristics in 2 commercial chicken hybrids
Abstract A trial was conducted to compare muscle traits and meat quality characteristics of the pectoralis muscle in 2 chicken commercial hybrids having standard (SBY) and high breast yield (HBY), respectively. A total of 2,124 one-day-old male chicks, equally divided into 2 experimental groups represented by strains (SBY and HBY), were grown using homogenous conditions and fed the same standard diets until reaching live weight of 4.2 kg at 53 and 55 d for the SBY and HBY groups, respectively. Thirty-six birds per each genotype were randomly selected, and their pectoralis major muscles were used to assess meat quality properties (color attributes, pH, drip loss, cook loss, Allo-Kramer shear values after cooking, moisture, proteins, total lipids, and ashes) as well as histological traits (cross-sectional area, frequency of abnormal fibers, and intramuscular fat infiltration). As expected, HBY genotype had higher breast yield (31.0 vs. 30.0%; P ≤ 0.05). Histological evaluations showed that HBY pectoralis muscles had higher cross-sectional fiber area coupled with a dramatically higher (P ≤ 0.001) incidence of abnormal fibers and more abundant infiltration of intramuscular fat. Moreover, histopathological anomalous features such as central nuclei, proliferation of endomysial and perimysial collagen, inflammatory infiltrate, and necrosis of the fibers were also observed. As for meat quality, SBY hybrid showed lower ultimate pH values (5.97 vs. 6.07; P ≤ 0.01), whereas overall color parameters were not affected by genotype. Breast meat from the HBY genotype also exhibited significantly lower ability to retain liquid during refrigerated storage (drip loss, 2.46 vs. 2.06%; P ≤ 0.05) and cooking (26.2 vs. 21.1%; P ≤ 0.05) as well as higher shear-force values (2.59 vs. 2.11 kg/g; P ≤ 0.001). Finally, with regard to chemical composition, significant differences (P ≤ 0.05) were detected in protein (22.8 vs. 23.5%) and lipid (1.65 vs. 1.82%) contents, which were significantly lower in the HBY hybrid, whereas moisture content tended (P = 0.07) to be inferior in the SBY hybrid
Indoor height determination of the new absolute gravimetric station of L'Aquila
In this paper we describe all the field operations and the robust post-processing proceduresto determine the height of the new absolute gravimetric station purposely selected to belong to a new absolute gravimetric network and located in the Science Faculty of the L’Aquila University. This site has been realized indoor in the Geomagnetism laboratory, so that the height cannot be measured directly, but linking it to the GNSS antenna of AQUI benchmark located on the roof of the same building, by a classical topographic survey. After the topographic survey, the estimated height difference between AQUI and the absolute gravimetric site AQUIgis 14.970±0.003 m. At the epoch of the 2018 gravimetric measures, the height of AQUI GNSS station was 712.974±0.003 m, therefore the estimated ellipsoidalheight of the gravimetric site at the epoch of gravity measurements is 698.004±0.005 m. Absolute gravity measurements are referred to the equipotential surface of gravity field, so that the knowledge of the geoidal undulation at AQUIg allows us to infer the orthometric height as 649.32 m
A device to characterize optical fibres
ATLAS is a general purpose experiment approved for the LHC collider at CERN.
An important component of the detector is the central hadronic calorimeter; for
its construction more than 600,000 Wave Length Shifting (WLS) fibres
(corresponding to a total length of 1,120 Km) have been used.
We have built and put into operation a dedicated instrument for the
measurement of light yield and attenuation length over groups of 20 fibres at a
time.
The overall accuracy achieved in the measurement of light yield
(attenuation length) is 1.5% (3%).
We also report the results obtained using this method in the quality control
of a large sample of fibres.Comment: 17 pages 20 figeres submitted to NIM journa
Water level and volume estimations of the Albano and Nemi lakes (central Italy)
In April 2006 an airborne laser scanning (LIDAR) survey of the Albano and Nemi craters was carried out to obtain
a high resolution digital terrain model (DTM) of the area. We have integrated the LIDAR survey of the
craters and the recent bathymetry of the Albano lake to achieve a complete DTM, useful for morphological studies.
In addition, with a GPS RTK survey (July 2007) we estimated the Albano and Nemi mean lake levels respectively
at 288.16 m and 319.02 m (asl). Based on the integrated DTM and the newly estimated water level
values, we evaluated about 21.7·106 m3 the water volume loss of the Albano lake from 1993 to 2007, with an
average rate of about 1.6·106 m3/yr
Focal Liver Lesion Classification and Characterization in Noncirrhotic Liver: A Prospective Comparison of Diffusion-Weighted Magnetic Resonance–Related Parameters
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