216 research outputs found
Recommended from our members
The design of an effective sensor fusion model for condition monitoring systems of turning processes
No full textHigh energy price and the increasing requirements of quality and low cost of products have created an urgent need to implement new technologies in current automated manufacturing environments. Condition monitoring systems of manufacturing processes have been recognised in recent years as one of the essential technologies that provide the competitive advantage in many manufacturing environments. This research aims to develop an effective sensor fusion model for turning processes for the detection of tool wear. Multi-sensors combined with a novelty detection algorithm and Learning Vector Quantisation (LVQ) neural networks are used in this research to detect tool wear and provide diagnostic and prognostic information. A novel approach, termed ASPST, (Automated Sensor and Signal Processing Selection System for Turning) is used to select the most appropriate sensors and signal processing methods. The aim is to reduce the number of sensors needed in the overall system and reduce the cost. The ASPST approach is based on simplifying complex sensory signals into a group of Sensory Characteristic Features (SCFs) and evaluating the sensitivity of these SCFs in detecting tool wear. A wide range of sensory signals (cutting forces, strain, acceleration, acoustic emission and sound) and signal processing methods are also implemented to verify the capability of the approach. A cost reduction method is also implemented based on eliminating the least utilised sensor in an attempt to reduce the overall cost of the system without sacrificing the capability of the condition monitoring system. The experimental results prove that the suggested approach provides a responsive and effective solution in monitoring tool wear in turning with reduced time and cost
Fusion breeder with enhanced safeguarding capabilities against nuclear weapon proliferation
No full textThe breeding capability of a fusion reactor for Pu-239 is analyzed to provide fissile fuel for LWRs as a prospective alternative in addition to existing methods of nuclear fuel enrichment, such as gas diffusion and gas centrifuge plants. The analysis is conducted for the catalyzed-(D,D) and (D,T) fusion reactors. Two different coolants (helium gas and Flibe "Li2BeF4") are selected for the nuclear heat transfer out of the fissile breeding zone fuelled with natural uranium. Depending on the type of fusion driver and coolant in the fission zone, power plant operation periods between 12 and 36 months are evaluated to achieve a fissile fuel enrichment quality between 3% and 4% under a first-wall fusion neutron energy load of 5 MW/m(2) and a plant factor of 75%. For unit fusion neutron energy flux on the first-wall, a catalyzed (D,D) fusion reactor can breed faster than a (D,T) reactor because the former is richer in neutrons than the latter. The Flibe coolant is superior to helium coolant with regard to fissile fuel breeding. During a plant operation over four years, enrichment grades between 4.4% and 8.9% are calculated. The denaturation of the plutonium fuel requires about 2 years of irradiation with fusion neutrons for all investigated cases. During this period, it is possible to breed a high quality, but denatured plutonium for light water reactors. This is an important factor with regard to international safeguarding. (C) 1998 Elsevier Science Ltd. All rights reserved
Design and evaluation of multispectral LiDAR for the recovery of arboreal parameters
No full textMultispectral light detection and ranging (LiDAR) has the potential to recover structural and physiological data from arboreal samples and, by extension, from forest canopies when deployed on aerial or space platforms. In this paper, we describe the design and evaluation of a prototype multispectral LiDAR system and demonstrate the measurement of leaf and bark area and abundance profiles using a series of experiments on tree samples “viewed from above” by tilting living conifers such that the apex is directed on the viewing axis. As the complete recovery of all structural and physiological parameters is ill posed with a restricted set of four wavelengths, we used leaf and bark spectra measured in the laboratory to constrain parameter inversion by an extended reversible jump Markov chain Monte Carlo algorithm. However, we also show in a separate experiment how the multispectral LiDAR can recover directly a profile of Normalized Difference Vegetation Index (NDVI), which is verified against the laboratory spectral measurements. Our work shows the potential of multispectral LiDAR to recover both structural and physiological data and also highlights the fine spatial resolution that can be achieved with time-correlated single-photon countin
Improved light-weighting potential of SS316L triply periodic minimal surface shell lattices by micro laser powder bed fusion
No full textMicro laser powder bed fusion (μLPBF), for the first time, enables fabrication of low-density triply periodic minimal surface (TPMS) shell lattices with smaller feature size. However, the understandings on the mechanical responses of lightweight TPMS structures by μLPBF are yet to be updated. Herein, stainless steel 316L TPMS shell lattices (i.e., Primitive (P), Diamond (D) and Gyroid (G)) with different shell thicknesses and cell orientations were fabricated by µLPBF. Low-density TPMS structures with shell thickness as small as ∼100 μm and relative density ∼5 % were realized. Quasi-static compression tests and finite element modelling were conducted to study their compressive responses. Their light-weighting potential related to the scaling behavior of mechanical properties as a function of relative density was analyzed. Results show with increasing relative density, the deformation mechanism transforms from localized collapse to homogeneous bulk deformation. P-type TPMS exhibits the highest anisotropy of stiffness, strength and energy absorption capability, while G-type TPMS is near-isotropic. [1 0 0] oriented D-type TPMS shows the highest strength and best light-weighting potential. Compared with conventional LPBF, the µLPBF TPMS structures demonstrate higher mechanical properties and superior light-weighting potential. Overall, this work highlights the superiority of the µLPBF technology in fabricating lightweight TPMS structures for mechanical applications.</p
The Ancient Gamete Fusogen HAP2 Is a Eukaryotic Class II Fusion Protein
No full textComment in What Came First-the Virus or the Egg? [Cell. 2017] Gamete fusion gone viral. [Sci Transl Med. 2017]International audienceSexual reproduction is almost universal in eukaryotic life and involves the fusion of male and female haploid gametes into a diploid cell. The sperm-restricted single-pass transmembrane protein HAP2-GCS1 has been postulated to function in membrane merger. Its presence in the major eukaryotic taxa-animals, plants, and protists (including important human pathogens like Plasmodium)-suggests that many eukaryotic organisms share a common gamete fusion mechanism. Here, we report combined bioinformatic, biochemical, mutational, and X-ray crystallographic studies on the unicellular alga Chlamydomonas reinhardtii HAP2 that reveal homology to class II viral membrane fusion proteins. We further show that targeting the segment corresponding to the fusion loop by mutagenesis or by antibodies blocks gamete fusion. These results demonstrate that HAP2 is the gamete fusogen and suggest a mechanism of action akin to viral fusion, indicating a way to block Plasmodium transmission and highlighting the impact of virus-cell genetic exchanges on the evolution of eukaryotic life
Overview of the JET results in support to ITER
No full textThe 2014-2016 JET results are reviewed in the light of their significance for optimising
the ITER research plan for the active and non-active operation. More than 60 h of plasma
operation with ITER first wall materials successfully took place since its installation in
2011. New multi-machine scaling of the type I-ELM divertor energy flux density to ITER
is supported by first principle modelling. ITER relevant disruption experiments and first
principle modelling are reported with a set of three disruption mitigation valves mimicking
the ITER setup. Insights of the L-H power threshold in Deuterium and Hydrogen are given,
stressing the importance of the magnetic configurations and the recent measurements of
fine-scale structures in the edge radial electric. Dimensionless scans of the core and pedestal
confinement provide new information to elucidate the importance of the first wall material on
the fusion performance. H-mode plasmas at ITER triangularity (H = 1 at βN ~ 1.8 and n/nGW
~ 0.6) have been sustained at 2 MA during 5 s. The ITER neutronics codes have been validated
on high performance experiments. Prospects for the coming D-T campaign and 14 MeV
neutron calibration strategy are reviewed
Author response
No full textDespite remarkable developments in diffraction unlimited super-resolution microscopy, in vivo nanoscopy of tissues and model organisms is still not satisfactorily established and rarely realized. RESOLFT nanoscopy is particularly suited for live cell imaging because it requires relatively low light levels to overcome the diffraction barrier. Previously, we introduced the reversibly switchable fluorescent protein rsEGFP2, which facilitated fast RESOLFT nanoscopy (Grotjohann et al., 2012). In that study, as in most other nanoscopy studies, only cultivated single cells were analyzed. Here, we report on the use of rsEGFP2 for live-cell RESOLFT nanoscopy of sub-cellular structures of intact Drosophila melanogaster larvae and of resected tissues. We generated flies expressing fusion proteins of alpha-tubulin and rsEGFP2 highlighting the microtubule cytoskeleton in all cells. By focusing through the intact larval cuticle, we achieved lateral resolution of <60 nm. RESOLFT nanoscopy enabled time-lapse recordings comprising 40 images and facilitated recordings 40 µm deep within fly tissues
The influence of red light on the aggregation of two castes of the ant, Lasius niger
No full textInsects are generally described as essentially blind to red wavelengths but sensitive to ultraviolet. Therefore, ants are generally reared in nests where "obscurity" is obtained by the use of a red filter. Yet, no study has been done in order to confirm this idea and to verify whether ants behave differently with or without red light. We performed aggregation experiments with the ant Lasius niger under red light and in total darkness to control the sensitivity of workers. Aggregation is a basic behavior associated with the origin of sociality and with the spatial organization of the colony. We demonstrate that L. niger is sensitive to red wavelengths. Moreover, we show that workers behave differently depending on their ethological caste: foragers aggregate well in total darkness but show low assembly under red light, whereas brood-tenders aggregate well in both conditions. For the first time, a link between vision, social organization and spatial patterns is revealed. The results are discussed relative to their adaptive value and relative to the physiology of the workers. Hypotheses are formulated concerning the acquisition of this change of behavior between castes. © 2004 Elsevier Ltd. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Particle fluxes and gross erosion at limiters in JET low-confinement mode plasmas measured with visible cameras
No full textPublisher Copyright: © 2025 The Author(s). Published by IOP Publishing Ltd on behalf of the IAEA.Deuterium (D) and beryllium (Be) fluxes are obtained in JET Low-confinement mode (L-mode) plasmas at the outer limiters of the first wall using calibrated visible cameras. They are inferred from the measured radiances using the spectroscopic S/XB method. From the fluxes, the effective gross erosion yield Yeff of the limiter surface is estimated. After discussing the uncertainties in the proposed methodology, we show the dependence of the deduced particle fluxes and Yeff of recent JET L-mode plasmas on: separatrix-limiter clearance, magnetic field and plasma current, neutral beam injection and ion cyclotron resonance heating power, average plasma density and majority ion mass, hydrogen (H), deuterium (D) and tritium (T). The results are in general accord with prior edge plasma L-mode understanding. Finally, the obtained Yeff yields are discussed in view of updated SDTrim surface-particle interaction code calculations. The possible contribution of parasitic light due to reflections from the divertor is examined.Peer reviewe
Roadmap on spatiotemporal light fields
No full textSpatiotemporal sculpturing of light pulse with ultimately sophisticated
structures represents the holy grail of the human everlasting pursue of
ultrafast information transmission and processing as well as ultra-intense
energy concentration and extraction. It also holds the key to unlock new
extraordinary fundamental physical effects. Traditionally, spatiotemporal light
pulses are always treated as spatiotemporally separable wave packet as solution
of the Maxwell's equations. In the past decade, however, more generalized forms
of spatiotemporally nonseparable solution started to emerge with growing
importance for their striking physical effects. This roadmap intends to
highlight the recent advances in the creation and control of increasingly
complex spatiotemporally sculptured pulses, from spatiotemporally separable to
complex nonseparable states, with diverse geometric and topological structures,
presenting a bird's eye viewpoint on the zoology of spatiotemporal light fields
and the outlook of future trends and open challenges.Comment: This is the version of the article before peer review or editing, as
submitted by an author to Journal of Optics. IOP Publishing Ltd is not
responsible for any errors or omissions in this version of the manuscript or
any version derived from i
- …
