2,679 research outputs found
From Design to Production Control Through the Integration of Engineering Data Management and Workflow Management Systems
At a time when many companies are under pressure to reduce "times-to-market"
the management of product information from the early stages of design through
assembly to manufacture and production has become increasingly important.
Similarly in the construction of high energy physics devices the collection of
(often evolving) engineering data is central to the subsequent physics
analysis. Traditionally in industry design engineers have employed Engineering
Data Management Systems (also called Product Data Management Systems) to
coordinate and control access to documented versions of product designs.
However, these systems provide control only at the collaborative design level
and are seldom used beyond design. Workflow management systems, on the other
hand, are employed in industry to coordinate and support the more complex and
repeatable work processes of the production environment. Commercial workflow
products cannot support the highly dynamic activities found both in the design
stages of product development and in rapidly evolving workflow definitions. The
integration of Product Data Management with Workflow Management can provide
support for product development from initial CAD/CAM collaborative design
through to the support and optimisation of production workflow activities. This
paper investigates this integration and proposes a philosophy for the support
of product data throughout the full development and production lifecycle and
demonstrates its usefulness in the construction of CMS detectors.Comment: 18 pages, 13 figure
Hydrogel microparticles for biosensing
Due to their hydrophilic, biocompatible, and highly tunable nature, hydrogel materials have attracted strong interest in the recent years for numerous biotechnological applications. In particular, their solution-like environment and non-fouling nature in complex biological samples render hydrogels as ideal substrates for biosensing applications. Hydrogel coatings, and later, gel dot surface microarrays, were successfully used in sensitive nucleic acid assays and immunoassays. More recently, new microfabrication techniques for synthesizing encoded particles from hydrogel materials have enabled the development of hydrogel-based suspension arrays. Lithography processes and droplet-based microfluidic techniques enable generation of libraries of particles with unique spectral or graphical codes, for multiplexed sensing in biological samples. In this review, we discuss the key questions arising when designing hydrogel particles dedicated to biosensing. How can the hydrogel material be engineered in order to tune its properties and immobilize bioprobes inside? What are the strategies to fabricate and encode gel particles, and how can particles be processed and decoded after the assay? Finally, we review the bioassays reported so far in the literature that have used hydrogel particle arrays and give an outlook of further developments of the field. Keywords: Hydrogel; Biosensor; Microparticle; Multiplex assayNovartis Institutes of Biomedical Research (Presidential Fellowship)Novartis Institutes of Biomedical Research (Education Office)National Cancer Institute (U.S.) (Grant 5R21CA177393-02)National Science Foundation (U.S.) (Grant CMMI-1120724)Institute for Collaborative Biotechnologies (Grant W911NF-09-0001)United States. Army Research Offic
Effect of processing gas on spatter generation and oxidation of TiAl6V4 alloy in laser powder bed fusion process
The atmosphere is a vital factor influencing powder degradation during laser powder bed fusion. Particularly, its purity, density, and thermal conductivity, can strongly affect spatter generation, thermal history, and oxidation. It is critical to understand the atmosphere-spatter properties relationship to enhance powder recyclability and overall process sustainability. Herein, the effect of processing gases, among pure Ar, (Ar+He), and He, on spatter generation and oxidation during TiAl6V4 processing is investigated. To evaluate their influence on impurity pickup and morphology of spatters, bulk chemical analysis and scanning electron microscopy were conducted. The nature and thickness of surface oxides on spatters were comprehensively examined using surface analysis tools including X-ray photoelectron spectroscopy, Auger electron spectroscopy, and nano secondary ion mass spectroscopy. The bulk chemical analysis showed a 70% increase in oxygen content and a 3-fold increase in nitrogen content from virgin to spatter collected in standard argon atmosphere. The increase of impurities was substantially lower for the spatters generated in He and the mixture of (Ar+He). The surface analysis showed that the spatter surface was covered with a uniform Ti- and Al-rich oxide layer along with Al-based oxide particulates. Finally, this study discusses the nature of oxide on TiAl6V4 spatters
Low-complexity transmit diversity scheme using moderate-sized signal constellations
In the conventional space-time coding technique [1], nT radio frequency (RF) chains are employed to transmit signals simultaneously from nT transmit antennas. In this Letter, a lowcomplexity transmit diversity scheme with nT = 2 transmit antennas is proposed. The proposed system employs only one RF chain as well as a low-complexity switch for transmission
Role of the Netrin-like Domain of Procollagen C-Proteinase Enhancer-1 in the Control of Metalloproteinase Activity
The netrin-like (NTR) domain is a feature of several extracellular proteins, most notably the N-terminal domain of tissue inhibitors of metalloproteinases (TIMPs), where it functions as a strong inhibitor of matrix metalloproteinases and some other members of the metzincin superfamily. The presence of a C-terminal NTR domain in procollagen C-proteinase enhancers (PCPEs), proteins that stimulate the activity of astacin-like tolloid proteinases, raises the possibility that this might also have inhibitory activity. Here we show that both long and short forms of the PCPE-1 NTR domain, the latter beginning at the N-terminal cysteine known to be critical for TIMP activity, show no inhibition, at micromolar concentrations, of several members of the metzincin superfamily, including matrix metalloproteinase-2, bone morphogenetic protein-1 (a tolloid proteinase), and different ADAMTS (a disintegrin and a metalloproteinase with thrombospondin motifs) proteinases from the adamalysin family. In contrast, we report that the NTR domain within PCPE-1 leads to superstimulation of bone morphogenetic protein-1 activity in the presence of heparin and heparan sulfate. These observations point to a new mechanism whereby binding to cell surface-associated or extracellular heparin-like sulfated glycosaminoglycans might provide a means to accelerate procollagen processing in specific cellular and extracellular microenvironments
Extreme Mountain Ultra-Marathon Leads to Acute but Transient Increase in Cerebral Water Diffusivity and Plasma Biomarkers Levels Changes.
Background: Pioneer studies demonstrate the impact of extreme sport load on the human brain, leading to threatening conditions for athlete's health such as cerebral edema. The investigation of brain water diffusivity, allowing the measurement of the intercellular water and the assessment of cerebral edema, can give a great contribution to the investigation of the effects of extreme sports on the brain. We therefore assessed the effect of supra-physiological effort (extreme distance and elevation changes) in mountain ultra-marathons (MUMs) athletes combining for the first time brain magnetic resonance imaging (MRI) and blood parameters. Methods:This longitudinal study included 19 volunteers (44.2 ± 9.5 years) finishing a MUM (330 km, elevation + 24000 m). Quantitative measurements of brain diffusion-weighted images (DWI) were performed at 3 time-points: Before the race, upon arrival and after 48 h. Multiple blood biomarkers were simultaneously investigated. Data analyses included brain apparent diffusion coefficient (ADC) and physiological data comparisons between three time-points. Results:The whole brain ADC significantly increased from baseline to arrival (p = 0.005) and then significantly decreased at recovery (p = 0.005) to lower values than at baseline (p = 0.005). While sodium, potassium, calcium, and chloride as well as hematocrit (HCT) changed over time, the serum osmolality remained constant. Significant correlations were found between whole brain ADC changes and osmolality (p = 0.01), cholesterol (p = 0.009), c-reactive protein (p = 0.04), sodium (p = 0.01), and chloride (p = 0.002) plasma level variations. Conclusions:These results suggest the relative increase of the inter-cellular volume upon arrival, and subsequently its reduction to lower values than at baseline, indicating that even after 48 h the brain has not fully recovered to its equilibrium state. Even though serum electrolytes may only indirectly indicate modifications at the brain level due to the blood brain barrier, the results concerning osmolality suggest that body water might directly influence the change in cerebral ADC. These findings establish therefore a direct link between general brain inter-cellular water content and physiological biomarkers modifications produced by extreme sport
Electromechanical, Thermal Properties And Radiation Hardness Tests Of Piezoelectric Actuators At Low Temperature
IPN Orsay participates, in the frame of the CARE project activities supported by EU, to the development of a fast cold tuning system for SRF cavities. The main task of IPN is the full characterization of piezoelectric actuators at low temperature T, and the study of their behaviour when subjected to fast neutrons radiation at T=4.2 K. In order to compare the performance of various industrial piezoelectric actuators, a new apparatus was developed and successfully used for measuring their electromechanical and thermal properties for T in the range 1.8 K-300 K. Different parameters were investigated as function of T: piezoelectric constant, dielectric and thermal properties including heating ΔT due to dielectric losses vs. modulating voltage Vmod and frequency f. We observed a decrease of the maximum displacement ΔX of the actuators tested from ΔX ~40μm @ 300K down to 1.8μm-3.5 μm @ 1.8K, depending on both material and fabrication process of the piezostacks. Besides, both material and fabrication process have a strong influence on the shape of the characteristics ΔX vs. T dependence. Finally a dedicated facility located at CERI institute (Orléans, France) for radiation hardness tests of actuators with fast neutrons at T=4.2 K was developed and the first beam tests results are summarized
Effect of layer thickness on spatter properties during laser powder bed fusion of Ti–6Al–4V
High layer thicknesses for laser powder bed fusion are promising for productivity increase. However, these are associated with increased process instability, spatter generation and powder degradation, crucial for alloys sensitive to oxygen. The effect of increasing layer thickness from 30 to 60 \ub5m is studied focusing on Ti-6Al-4V spatter formation during LPBF and its characterisation, with scanning and transmission electron microscopy, combustion analysis and X-ray photoelectron spectroscopy. Results indicate that spatters are covered with a uniform Ti-Al-based oxide layer and Al-rich oxide particulates, the thickness of which is about twice that present on virgin powder. The oxygen content was about 60% higher in spatters compared to the virgin powder. The study highlights that increasing the layer thickness to 60 \ub5m permits to reduce the total generation of spatters by ∼40%, while maintaining similar spatter characteristics and static tensile properties. Hence, this allows to increase build rate without compromising process robustness
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