Mechanical performance of composite bonded joints in the presence of localised process-induced zero-thickness defects

Processing parameters and environmental conditions can introduce variation into the performance of adhesively bonded joints. The effect of such variation on the mechanical performance of the joints is not well understood. Moreover, there is no validated nondestructive inspection (NDI) available to ensure bond integrity post-process and in-service so as to guarantee initial and continued airworthiness in aerospace sector. This research studies polymer bond defects produced in the laboratory scale single-lap composite-to-composite joints that may represent the process-induced defects occurring in actual processing scenarios such as composite joining and repair in composite aircrafts. The effect of such defects on the degradation of a joint's mechanical performance is then investigated via quasi-static testing in conjunction with NDI ultrasonic C-scanning and pulsed thermography. This research is divided into three main sections: 1- manufacturing carbon fibre-reinforced composite joints containing representative nearly zero-thickness bond defects, 2- mechanical testing of the composite joints, and 3- assessment of the NDI capability for detection of the bond defects in such joints

Stimulation of shrimp (Penaeus monodon) hemocytes by lipopolysaccharide-like molecules derived from Novacq™

Immune stimulation through feed additives is a promising strategy that can help to combat disease in shrimp farming and reduce the use of antibiotics and other chemotherapeutics. The present study investigated the in vitro immunostimulatory effects of lipopolysaccharide (LPS)-like molecules isolated from the microbial based feed additive Novacq™ (N-LPS). The presence of LPS-like molecules was confirmed and quantified Novacq™ using a HEK-TLR4 reporter cell line. Primary hemocytes isolated from adult Penaeus monodon were used to measure the immunostimulatory of N-LPS compared with the control group that were treated with E. coli derived LPS (E-LPS). The N-LPS stimulated a rapid and significant induction of the phenoloxidase (PO) response in the hemocytes. The PO response increased with exposure time and LPS concentration and was significantly higher compared with an E. coli LPS (E-LPS) control. In addition, using gene expression data, we quantified the transcriptome response of the hemocytes at 15, 30 and 60 mins post stimulation. Compared with the controls, the N-LPS treated hemocytes had a significant up-regulation of genes involved in the immune system modulation and control at all time-points. Most noteworthy was the significant induction of transcripts that function as serine protease inhibitors (namely SERPINs), that regulate the overexpression of the PO system. Transcription factors from the Notch family which directly regulate the expression of many immune genes were also induced within the hemocytes. Additionally, we also saw a strong up-regulation of crustacean hyperglycemic hormone (CHH) transcripts, an important neuropeptide involved in immune function. Overall, the transcriptome profile of the hemocytes suggests that the LPS component of Novacq™ is highly immunostimulatory and generates a strong PO response in vitro. The subsequent transcriptional response appears to be directed towards preventing further activation of the PO system most likely in an attempt to limit cytoxicity to the host. Our study highlights the immunostimulatory ability of Novacq™ and provides further evidence of the positive health benefits this microbial based feed additive can have in shrimp.</p

Detecting failure of a material handling system through a cognitive twin

This paper describes a methodology for developing a digital twin (DT) based on a rich semantic model and principles of system engineering. The aim is to provide a general model of digital twins (DT) that can improve decision making based on semantic reasoning on real-time system monitoring. The methodology has been tested on a laboratory pilot plant that acts as a material handling system. The key contribution of this research is to propose a generic information model for DT using foundational ontology and principles of systems engineering. The efficacy of the proposed methodology is demonstrated by the automatic detection of a component level failure using semantic reasoning

A Polyadenylation Factor Subunit Implicated in Regulating Oxidative Signaling in Arabidopsis thaliana

BACKGROUND: Plants respond to many unfavorable environmental conditions via signaling mediated by altered levels of various reactive oxygen species (ROS). To gain additional insight into oxidative signaling responses, Arabidopsis mutants that exhibited tolerance to oxidative stress were isolated. We describe herein the isolation and characterization of one such mutant, oxt6. METHODOLOGY/PRINCIPAL FINDINGS: The oxt6 mutation is due to the disruption of a complex gene (At1g30460) that encodes the Arabidopsis ortholog of the 30-kD subunit of the cleavage and polyadenylation specificity factor (CPSF30) as well as a larger, related 65-kD protein. Expression of mRNAs encoding Arabidopsis CPSF30 alone was able to restore wild-type growth and stress susceptibility to the oxt6 mutant. Transcriptional profiling and single gene expression studies show elevated constitutive expression of a subset of genes that encode proteins containing thioredoxin- and glutaredoxin-related domains in the oxt6 mutant, suggesting that stress can be ameliorated by these gene classes. Bulk poly(A) tail length was not seemingly affected in the oxt6 mutant, but poly(A) site selection was different, indicating a subtle effect on polyadenylation in the mutant. CONCLUSIONS/SIGNIFICANCE: These results implicate the Arabidopsis CPSF30 protein in the posttranscriptional control of the responses of plants to stress, and in particular to the expression of a set of genes that suffices to confer tolerance to oxidative stress

Measurements of azimuthal anisotropies of jet production in Pb+Pb collisions at root sNN=5.02 TeV with the ATLAS detector

The azimuthal variation of jet yields in heavy-ion collisions provides information about the path-length dependence of the energy loss experienced by partons passing through the hot, dense nuclear matter known as the quark–gluon plasma. This paper presents the azimuthal anisotropy coefficients v2, v3, and v4 measured for jets in Pb + Pb collisions at √ sNN = 5.02 TeV using the ATLAS detector at the LHC. The measurement uses data collected in 2015 and 2018, corresponding to an integrated luminosity of 2.2 nb−1. The vn values are measured as a function of the transverse momentum of the jets between 71 and 398 GeV and the event centrality. A nonzero value of v2 is observed in all but the most central collisions. The value of v2 is largest for jets with lower transverse momentum, with values up to 0.05 in mid-central collisions. A smaller, nonzero value of v3 of approximately 0.01 is measured with no significant dependence on jet pT or centrality, suggesting that fluctuations in the initial state play a small but distinct role in jet energy loss. No significant deviation of v4 from zero is observed in the measured kinematic region.G. Aad … P. Jackson … A.X.Y. Kong … J.L. Oliver … H. Potti … T.A. Ruggeri … A.S. Sharma … M.J. White … et al. [The ATLAS Collaboration

Determination of the parton distribution functions of the proton using diverse ATLAS data from pp collisions at root s = 7, 8 and 13 TeV

This paper presents an analysis at next-to-next to-leading order in the theory of quantum chromodynamics for the determination of a new set of proton parton distribution functions using diverse measurements in pp collisions at √s = 7, 8 and 13 TeV, performed by the ATLAS experiment at the Large Hadron Collider, together with deep inelastic scattering data from ep collisions at the HERA collider. The ATLAS data sets considered are differential cross-section measurements of inclusive W± and Z/γ ∗ boson production, W± and Z boson production in association with jets, tt ¯ production, inclusive jet production and direct photon production. In the analysis, particular attention is paid to the correlation of systematic uncertainties within and between the various ATLAS data sets and to the impact of model, theoretical and parameterisation uncertainties. The resulting set of parton distribution functions is called ATLASpdf21.G. Aad … P. Jackson … A.X.Y. Kong … J.L. Oliver … H. Potti … T.A. Ruggeri … A.S. Sharma …E. X. L. Ting ... M.J. White … et al. (The ATLAS Collaboration

Search for new phenomena in multi-body invariant masses in events with at least one isolated lepton and two jets using root s = 13 TeV proton-proton collision data collected by the ATLAS detector

Published: July 26, 2023A search for resonances in events with at least one isolated lepton (e or μ) and two jets is performed using 139 fb⁻¹ of √s = 13 TeV proton-proton collision data recorded by the ATLAS detector at the LHC. Deviations from a smoothly falling background hypothesis are tested in three- and four-body invariant mass distributions constructed from leptons and jets, including jets identified as originating from bottom quarks. Model-independent limits on generic resonances characterised by cascade decays of particles leading to multiple jets and leptons in the final state are presented. The limits are calculated using Gaussian shapes with different widths for the invariant masses. The multi-body invariant masses are also used to set 95% confidence level upper limits on the cross-section times branching ratios for the production and subsequent decay of resonances predicted by several new physics scenarios.G. Aad ... E. K. Filmer ... P. Jackson ... A. X. Y. Kong ... H. Potti ... T. A. Ruggeri ... E. X. L. Ting ... M. J. White ... et al. (The ATLAS collaboration

Measurements of the Higgs boson inclusive and differential fiducial cross-sections in the diphoton decay channel with pp collisions at s root = 13 TeV with the ATLAS detector

Published: August 2, 2022A measurement of inclusive and differential fiducial cross-sections for the production of the Higgs boson decaying into two photons is performed using 139 fb−1 of proton-proton collision data recorded at s√ = 13 TeV by the ATLAS experiment at the Large Hadron Collider. The inclusive cross-section times branching ratio, in a fiducial region closely matching the experimental selection, is measured to be 67 ± 6 fb, which is in agreement with the state-of-the-art Standard Model prediction of 64 ± 4 fb. Extrapolating this result to the full phase space and correcting for the branching ratio, the total cross-section for Higgs boson production is estimated to be 58 ± 6 pb. In addition, the cross-sections in four fiducial regions sensitive to various Higgs boson production modes and differential cross-sections as a function of either one or two of several observables are measured. All the measurements are found to be in agreement with the Standard Model predictions. The measured transverse momentum distribution of the Higgs boson is used as an indirect probe of the Yukawa coupling of the Higgs boson to the bottom and charm quarks. In addition, five differential cross-section measurements are used to constrain anomalous Higgs boson couplings to vector bosons in the Standard Model effective field theory framework.The ATLAS collaboration, G. Aad ... P.Jackson ... A.X.Y Kong ... H.Potti ... T.A. Ruggeri ... A.S.Sharma ... E.X.L.Ting ... M.J.White ... et al

Observation of electroweak production of two jets in association with an isolated photon and missing transverse momentum, and search for a Higgs boson decaying into invisible particles at 13 TeV with the ATLAS detector

This paper presents a measurement of the electroweak production of two jets in association with a Zγ pair, with the Z boson decaying into two neutrinos. It also presents a search for invisible or partially invisible decays of a Higgs boson with a mass of 125 GeV produced through vector-boson fusion with a photon in the final state. These results use data from LHC proton–proton collisions at s√ = 13 TeV collected with the ATLAS detector and corresponding to an integrated luminosity of 139 fb⁻¹. The event signature, shared by all benchmark processes considered for the measurements and searches, is characterized by a significant amount of unbalanced transverse momentum and a photon in the final state, in addition to a pair of forward jets. Electroweak Zγ production in association with two jets is observed in this final state with a significance of 5.2 (5.1 expected) standard deviations. The measured fiducial cross-section for this process is 1.31 ± 0.29 fb. An observed (expected) upper limit of 0.37 (0.34(+0.15)(−0.10)) at 95% confidence level is set on the branching ratio of a 125 GeV Higgs boson to invisible particles, assuming the Standard Model production cross-section. The signature is also interpreted in the context of decays of a Higgs boson into a photon and a dark photon. An observed (expected) 95% CL upper limit on the branching ratio for this decay is set at 0.018 (0.017(+0.007)(−0.005)), assuming the Standard Model production cross-section for a 125 GeV Higgs boson.G. Aad … P. Jackson … A.X.Y. Kong … J.L. Oliver … H. Potti … T.A. Ruggeri … A.S. Sharma … M.J. White … et al. [The ATLAS Collaboration

Search for Higgs boson decays into a pair of pseudoscalar particles in the bb mu mu final state with the ATLAS detector in pp collisions at root s=13TeV

This paper presents a search for decays of the Higgs boson with a mass of 125 GeV into a pair of new pseudoscalar particles, H → aa, where one a-boson decays into a b-quark pair and the other into a muon pair. The search uses 139 fb−1 of proton-proton collision data at a center-of-mass energy of ffiffiffi sp¼ 13 TeVrecorded between 2015 and 2018 by the ATLAS experiment at the LHC. A narrow dimuon resonance is searched for in the invariant mass spectrum between 16 GeV and 62 GeV. The largest excess of events above the Standard Model backgrounds is observed at a dimuon invariant mass of 52 GeVand corresponds to a local (global) significance of 3.3σ (1.7σ). Upper limits at 95% confidence level are placed on the branching ratio of the Higgs boson to the bbμμ final state, BðH → aa → bbμμÞ, and are in the range 0.2–4.0 × 10−4, depending on the signal mass hypothesis.G. Aad ... P. Jackson ... H. Potti ... M.J. White ... et al. (ATLAS Collaboration