205 research outputs found
Determination of Corresponding Temperature Distribution within CFRP during Laser Cutting
AbstractLaser cutting of carbon fiber reinforced plastics as a thermal process results in a thermal load on the material. Due to the high thermal conductivity of carbon fibers, residual heat is conducted along the fibers, away from the laser interaction zone. Common temperature measurement techniques, such as pyrometry and infrared thermography only allow for observation of the temperature development on the surface of the material. In order to achieve information about the temperature distribution within the material during the cutting process, thermochromes and thermocouples were implemented during the laminating process of CFRP. The cutting tests were performed with a single mode fiber laser emitting a continuous wave and at a wavelength of λ = 1080 nm
Effects of Age, Gender, Obesity, and Diabetes on the Efficacy and Safety of the Selective A(2A) Agonist Regadenoson Versus Adenosine in Myocardial Perfusion Imaging Integrated ADVANCE-MPI Trial Results
ObjectivesTo compare the effects of age, gender, body mass index, and diabetes on the safety and efficacy of regadenoson stress myocardial perfusion imaging, and to assess the noninferiority of regadenoson to adenosine for the detection of reversible myocardial perfusion defects.BackgroundPrevious reports have shown that a fixed unit bolus of regadenoson is safe and noninferior to adenosine for the detection of reversible perfusion defects by radionuclide imaging.MethodsUsing a database of 2,015 patients, we evaluated the effects of age, gender, body mass index, and diabetes on the safety and efficacy of regadenoson compared to adenosine.ResultsFor detection of ischemia relative to adenosine, noninferiority was demonstrated for all patients (agreement rate difference 0%, 95% CI −6.2% to +6.8%). The average agreement rate between adenosine-adenosine and adenosine-regadenoson were 0.62 ± 0.03 and 0.63 ± 0.02. Detection of ischemia was also comparable in specific subgroups. Agreement was less for both agents in women versus men with moderate and large areas of ischemia. Compared to adenosine, regadenoson had a lower combined symptom score and less chest pain, flushing, and throat, neck, or jaw pain, but more headache and gastrointestinal discomfort. This was true in nearly all subgroups. Regadenoson patients reported feeling more comfortable (1.7 ± .02 vs. 1.9 ± 0.03, p < 0.001). Based on the overall tolerability score, women felt less comfortable than men with both stress agents. Image quality was rated good or excellent in 92% for both agents.ConclusionsRegadenoson can be safely administered as a fixed unit bolus and is as efficacious as adenosine in detecting ischemia regardless of age, gender, body mass index, and diabetes. Regadenoson is better tolerated overall and across various subgroups
Robot based remote laser cutting of three-dimensional automotive composite parts with thicknesses up to 5mm
With the intention to develop a robot based laser cutting process for automotive 3D parts with varying thickness consisting of carbon fibre reinforced plastics (CFRP), strategies of 2D investigations were adapted. The used setup consist of a fibre guided nanosecond pulsed laser with an average power of P L = 1.5 kW, a 6-axis robot and a 3D programmable focusing optic (I-PFO). In a first instance strategies for the remote cutting of material with a thickness of d = 5 mm were developed and optimized concerning cutting efficiency and quality. In a second step the results were transferred to a robot based 3D cutting process. Main challenges are the consideration of the correct angle of incidence, the geometric constancy and the accessibility of the cutting geometry by the I-PFO for complex shaped 3D parts. Therewith, “cutting-on-the-fly” strategies were realized for automated trimming and drilling of large automotive structures
Lake-size dependency of wind shear and convection as controls on gas exchange
High-frequency physical observations from 40 temperate lakes were used to examine the relative contributions of wind shear (u*) and convection (w*) to turbulence in the surface mixed layer. Seasonal patterns of u* and w* were dissimilar; u* was often highest in the spring, while w * increased throughout the summer to a maximum in early fall. Convection was a larger mixed-layer turbulence source than wind shear (u */w*-1 for lakes* and w* differ in temporal pattern and magnitude across lakes, both convection and wind shear should be considered in future formulations of lake-air gas exchange, especially for small lakes. © 2012 by the American Geophysical Union.Jordan S. Read, David P. Hamilton, Ankur R. Desai, Kevin C. Rose, Sally MacIntyre, John D. Lenters, Robyn L. Smyth, Paul C. Hanson, Jonathan J. Cole, Peter A. Staehr, James A. Rusak, Donald C. Pierson, Justin D. Brookes, Alo Laas, and Chin H. W
Distinctive effects of allochthonous and autochthonous organic matter on CDOM spectra in a tropical lake
Despite the increasing understanding about differences in carbon cycling between temperate and tropical freshwater systems, our knowledge on the importance of organic matter (OM) pools on light absorption properties in tropical lakes is very scarce. We performed a factorial mesocosm experiment in a tropical lake (Minas Gerais, Brazil) to evaluate the effects of increased concentrations of al-lochthonous and autochthonous OM, and differences in light availability on the light absorption characteristics of chromophoric dissolved organic matter (CDOM). Autochthonous OM deriving from phytoplankton (similar to Chl a) was stimulated by addition of nutrients, while OM from degradation of terrestrial leaves increased allochthonous OM, and neutral shading was used to manipulate light availability. Effects of the additions and shading on DOC, Chl a, nutrients, total suspended solid concentrations (TSM) and spectral CDOM absorption were monitored every 3 days. CDOM quality was characterized by spectral indices (S250-450, S275-295, S350-450, S-R and SUVA(254)). Effects of carbon sources and shading on the spectral CDOM absorption was investigated through principal component (PCA) and redundancy (RDA) analyses. The two different OM sources affected CDOM quality very differently and shading had minor effects on OM levels, but significant effects on OM quality, especially in combination with nutrient additions. Spectral indices (S250-450 and S-R) were mostly affected by allochthonous OM addition. The PCA showed that enrichment by allochthonous carbon had a strong effect on the CDOM spectra in the range between 300 and 400 nm, while the increase in autochthonous carbon increased absorption at wavelengths below 350 nm. Our study shows that small inputs of allochthonous OM can have large effects on the spectral light absorption compared to large production of autochthonous OM, with important implications for carbon cycling in tropical lakes.Peer reviewe
Linking shifts in bacterial community with changes in dissolved organic matter pool in a tropical lake
Bacterioplankton communities have a pivotal role in the global carbon cycle. Still the interaction between microbial community and dissolved organic matter (DOM) in freshwater ecosystems remains poorly understood. Here, we report results from a 12-day mesocosm study performed in the epilimnion of a tropical lake, in which inorganic nutrients and allochthonous DOM were supplemented under full light and shading. Although the production of autochthonous DOM triggered by nutrient addition was the dominant driver of changes in bacterial community structure, temporal covariations between DOM optical proxies and bacterial community structure revealed a strong influence of community shifts on DOM fate. Community shifts were coupled to a successional stepwise alteration of the DOM pool, with different fractions being selectively consumed by specific taxa Typical freshwater clades as Limnohabitans and Sporichthyaceae were associated with consumption of low molecular weight carbon, whereas Gammaproteobacteria and Flavobacteria utilized higher molecular weight carbon, indicating differences in DOM preference among Glades. Importantly. Verrucomicrobiaceae were important in the turnover of freshly produced autochthonous DOM, ultimately affecting light availability and dissolved organic carbon concentrations. Our findings suggest that taxonomically defined bacterial assemblages play definite roles when influencing DOM fate, either by changing specific fractions of the DOM pool or by regulating light availability and DOC levels. (C) 2019 Elsevier B.V. All rights reserved.Peer reviewe
Effects of Free Fatty Acids Per Se on Glucose Production, Gluconeogenesis, and Glycogenolysis
Wind and trophic status explain within and among-lake variability of algal biomass
Phytoplankton biomass and production regulates key aspects of freshwater ecosystems yet its variability and subsequent predictability is poorly understood. We estimated within-lake variation in biomass using high-frequency chlorophyll fluorescence data from 18 globally distributed lakes. We tested how variation in fluorescence at monthly, daily, and hourly scales was related to high-frequency variability of wind, water temperature, and radiation within lakes as well as productivity and physical attributes among lakes. Within lakes, monthly variation dominated, but combined daily and hourly variation were equivalent to that expressed monthly. Among lakes, biomass variability increased with trophic status while, within-lake biomass variation increased with increasing variability in wind speed. Our results highlight the benefits of high-frequency chlorophyll monitoring and suggest that predicted changes associated with climate, as well as ongoing cultural eutrophication, are likely to substantially increase the temporal variability of algal biomass and thus the predictability of the services it provides.Peer reviewe
Managing changes initiated by industrial big data technologies : a technochange management model
With the adoption of Internet of Things and advanced data analytical technologies in manufacturing firms, the industrial sector has launched an evolutionary journey toward the 4th industrial revolution, or so called Industry 4.0. Industrial big data is a core component to realize the vision of Industry 4.0. However, the implementation and usage of industrial big data tools in manufacturing firms will not merely be a technical endeavor, but can also lead to a thorough management reform. By means of a comprehensive review of literature related to Industry 4.0, smart manufacturing, industrial big data, information systems (IS) and technochange management, this paper aims to analyze potential changes triggered by the application of industrial big data in manufacturing firms, from technological, individual and organizational perspectives. Furthermore, in order to drive these changes more effectively and eliminate potential resistance, a conceptual technochange management model was developed and proposed. Drawn upon theories reported in literature of IS technochange management, this model proposed four types of interventions that can be used to copy with changes initiated by industrial big data technologies, including human process intervention, techno-structural intervention, human resources management intervention and strategic intervention. This model will be of interests and value to practitioners and researchers concerned with business reforms triggered by Industry 4.0 in general and by industrial big data technologies in particular
Detecting spatio-temporal mortality clusters of European countries by sex and ag
[EN] Background: Mortality decreased in European Union (EU) countries during the last century. Despite these similar
trends, there are still considerable differences in the levels of mortality between Eastern and Western European
countries. Sub-group analysis of mortality in Europe for different age and sex groups is common, however to our
knowledge a spatio-temporal methodology as in this study has not been applied to detect significant spatial
dependence and interaction with time. Thus, the objective of this paper is to quantify the dynamics of mortality in
Europe and detect significant clusters of mortality between European countries, applying spatio-temporal
methodology. In addition, the joint evolution between the mortality of European countries and their neighbours over
time was studied.
Methods: The spatio-temporal methodology used in this study takes into account two factors: time and the
geographical location of countries and, consequently, the neighbourhood relationships between them. This
methodology was applied to 26 European countries for the period 1990-2012.
Results: Principally, for people older than 64 years two significant clusters were obtained: one of high mortality
formed by Eastern European countries and the other of low mortality composed of Western countries. In contrast, for
ages below or equal to 64 years only the significant cluster of high mortality formed by Eastern European countries
was observed. In addition, the joint evolution between the 26 European countries and their neighbours during the
period 1990-2012 was confirmed. For this reason, it can be said that mortality in EU not only depends on differences in
the health systems, which are a subject to national discretion, but also on supra-national developments.
Conclusions: This paper proposes statistical tools which provide a clear framework for the successful implementation
of development public policies to help the UE meet the challenge of rethinking its social model (Social Security and
health care) and make it sustainable in the medium term.The authors are grateful for the financial support provided by the Ministry of Economy and Competitiveness, project MTM2013-45381-P. Adina Iftimi gratefully acknowledges financial support from the MECyD (Ministerio de Educacion, Cultura y Deporte, Spain) Grant FPU12/04531. Francisco Montes is grateful for the financial support provided by the Spanish Ministry of Economy and Competitiveness, project MTM2016-78917-R. The research by Patricia Carracedo and Ana Debon has been supported by a grant from the Mapfre Foundation.Carracedo-Garnateo, P.; Debón Aucejo, AM.; Iftimi, A.; Montes-Suay, F. (2018). Detecting spatio-temporal mortality clusters of European countries by sex and ag. International Journal for Equity in Health. 17:1-19. https://doi.org/10.1186/s12939-018-0750-zS11917Anderson TW, Goodman LA. Statistical Inference about Markov Chains. Ann Math Stat. 1957; 28(1):89–110.Anselin L. 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