A finite element (FE) modelling methodology is presented to analyse the dynamic response of carbon fibre reinforced polymer laminates when loaded by the shock wave generated by an airborne explosive ...blast. An FE model is developed to calculate the out-of-plane deformation of laminates over the entire duration of an explosive blast loading event. The FE model can also predict the initiation and propagation of delamination cracking and ply rupture in laminates. The response of the composite target plates to explosive blast loading was modelled in the FE program Abaqus using an explicit solver. The explosive air blast load was modelled using the ConWep algorithm. The accuracy of the FE model is assessed using experimental data obtained from small-scale far-field and near-field explosive blast tests performed on carbon-polyester and carbon-vinyl ester laminates. The FE model can predict the dynamic deformation of the laminates to within an accuracy of ~10%. The model can also accurately determine delamination cracks and broken plies.
•A novel approach to achieve solvent switching and focusing of sub-column-volume analyte fractions in liquid chromatography is presented.•The proposed method relies on temperature effects on ...retention to induce solvent switching and focusing of anlaytes in a back-flush arrangement.•The principle is demonstrated using three small aromatic analytes.
A novel approach to achiveve solvent switching and focusing of sub-column-volume analyte fractions in liquid chromatography is presented. By altering the temperature between loading and elution in back-flush mode, solvent transfer of analytes and focusing occurs, provided that the analytes exhibit temperature dependent retention on a given trap column. When retention on the trap decreases with increasing temperature, which is almost always the case, the loading of the trap-column takes place at a higher temperature than the elution. This principle is demonstrated using three small aromatic molecules (toluene, p-xylene and benzophenone) on a capillary monolithic column. On this column, the analytes show a traditional van’t Hoff dependence on temperature with enthalpy effects of, −15, −16 and −18kJmol−1, respectively, for a mobile phase of 25% acetonitrile in water. The column was loaded at 110°C, cooled in an ice bath and eluted in back-flush mode at 0°C. When operated in this way, the analytes are transferred from the loading solvent to the elution solvent, achieving solvent switching. Substantial focusing can also be obtained if the desorption solvent is stronger than the loading solvent.
Many industrial enzymes exhibit macro- and micro-heterogeneity due to co-occurring post-translational modifications. The resulting proteoforms may have different activity and stability and, ...therefore, the characterization of their distributions is of interest in the development and monitoring of enzyme products. Protein glycosylation may play a critical role as it can influence the expression, physical and biochemical properties of an enzyme.
We report the use of hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS) to profile intact glycoform distributions of high mannose-type N-glycosylated proteins, using an industrially produced fungal lipase for the food industry as an example. We compared these results with conventional reversed phase LC-MS (RPLC-MS) and sodium dodecyl sulfate–polyacrylamide gel-electrophoresis (SDS-PAGE). HILIC appeared superior in resolving lipase heterogeneity, facilitating mass assignment of N-glycoforms and sequence variants. In order to understand the glycoform selectivity provided by HILIC, fractions from the four main HILIC elution bands for lipase were taken and subjected to SDS-PAGE and bottom-up proteomic analysis. These analyses enabled the identification of the most abundant glycosylation sites present in each fraction and corroborated the capacity of HILIC to separate protein glycoforms based on the number of glycosylation sites occupied.
Compared to RPLC-MS, HILIC-MS reducted the sample complexity delivered to the mass spectrometer, facilitating the assignment of the masses of glycoforms and sequence variants as well as increasing the number of glycoforms detected (69 more proteoforms, 177% increase). The HILIC-MS method required relatively short analysis time (<30 min), in which over 100 glycoforms were distinguished.
We suggest that HILIC(-MS) can be a valuable tool in characterizing bioengineering processes aimed at steering protein glycoform expression as well as to check the consistency of product batches.
Display omitted
•Comparison of SDS-PAGE, RPLC-MS and HILIC-MS of intact lipase.•HILIC-MS allows for high-resolution separation of lipase glycoforms.•In-depth glycoform characterization combining bottom-up and intact-protein methods.
A critical challenge in genetic diagnostics is the computational assessment of candidate splice variants, specifically the interpretation of nucleotide changes located outside of the highly conserved ...dinucleotide sequences at the 5′ and 3′ ends of introns. To address this gap, we developed the Super Quick Information-content Random-forest Learning of Splice variants (SQUIRLS) algorithm. SQUIRLS generates a small set of interpretable features for machine learning by calculating the information-content of wild-type and variant sequences of canonical and cryptic splice sites, assessing changes in candidate splicing regulatory sequences, and incorporating characteristics of the sequence such as exon length, disruptions of the AG exclusion zone, and conservation. We curated a comprehensive collection of disease-associated splice-altering variants at positions outside of the highly conserved AG/GT dinucleotides at the termini of introns. SQUIRLS trains two random-forest classifiers for the donor and for the acceptor and combines their outputs by logistic regression to yield a final score. We show that SQUIRLS transcends previous state-of-the-art accuracy in classifying splice variants as assessed by rank analysis in simulated exomes, and is significantly faster than competing methods. SQUIRLS provides tabular output files for incorporation into diagnostic pipelines for exome and genome analysis, as well as visualizations that contextualize predicted effects of variants on splicing to make it easier to interpret splice variants in diagnostic settings.
The damage resistance of 3D textile composites when subjected to shock wave loading caused by an explosive blast is experimentally investigated. Non-crimp 3D orthogonal textile carbon-epoxy ...composites with different volume contents of through-thickness z-binder yarns are subjected to explosive blasts of increasing intensity, and the resultant damage is compared to a 2D woven carbon-epoxy laminate. At high blast impulse, the 3D textile composites are highly effective at resisting large delamination crack growth, and display superior damage resistance compared to the 2D laminate. The delamination resistance of the 3D textile composites at high blast impulse increases with their z-binder yarn content, and this correlates with higher modes I and II interlaminar fracture toughness properties. Furthermore, the 2D laminate completely shatters under high blast impulse whereas the 3D textile composites remain intact, which is also evidence of higher explosive damage resistance.
An experimental investigation is presented into the explosive blast response of fibre-reinforced polymer laminates used in naval ship structures. Blast tests using plastic explosive charges were ...performed in air on square target plates made of carbon-polyester, glass-polyester, carbon-vinyl ester or glass-vinyl ester laminates, which are composite materials used in naval ships. The laminates were dynamically loaded by shock waves of increasing pressure and impulse, and the deformation, damage and residual mechanical properties were determined. The amount of blast-induced damage and the post-blast mechanical properties depend on both the fibre reinforcement and polymer matrix. E-glass laminates have higher resistance to blast-induced delamination cracking and tow rupture than carbon fibre composites. Furthermore, glass or carbon fibre laminates with a vinyl ester matrix have superior blast damage resistance compared to composites with a polyester matrix. The higher damage resistance is attributed to the higher flexural strain energy capacity and interlaminar fracture toughness properties of laminates containing glass fibres or vinyl ester matrix.
•Comparison explosive blast response of metals and composites.•Blast deformation resistance correlated with tensile strain energy density of material.•Blast resistance of materials dependent on ...thickness and areal density.•Validated finite element model to predict deformation and damage to metals and composites.
Naval ships, military aircraft and land defence platforms are mostly constructed using steel, aluminium alloy, carbon fibre composite and/or glass fibre composite materials. Defence platforms are at risk from shock wave loads generated by explosive events, and therefore it is imperative that the construction materials are resistant to blast-induced deformation and damage. A comparative assessment is presented into the dynamic deformation and damage of metals and composites representative of naval construction materials when subjected to explosive air blasts. Flat plates of equal thickness (4 mm) or plates of similar areal density (in the range 6.2–9.2 kg/m2) made of the four materials were subjected to explosive blasts. Experimental blast testing and finite element (FE) modelling revealed that when the plate thickness was the same (4 mm) then the steel experienced less deformation (by ∼50–60%) and plasticity than the aluminium alloy due to its higher mechanical properties. The steel and aluminium plates were more resistance to blast-induced deformation (by up to ∼260–320% and ∼130–145% respectively) than the composite materials of the same thickness (4 mm). However, when the materials are compared on similar areal density, which is critical for lightweight design, the blast performance of the composite materials was similar to aluminium alloy and superior to steel. Deformation of the steel was up to 50% higher than the other construction materials, with the percentage increase rising with blast impulse.
Three-nucleon force and continuum play important roles in reproducing the properties of atomic nuclei around driplines. Therefore it is valuable to build up a theoretical framework where both effects ...can be taken into account to solve the nuclear Schrödinger equation. To this end, in this letter, we have expressed the chiral three-nucleon force within the continuum Berggren representation, so that bound, resonant and continuum states can be treated on an equal footing in the complex-momentum space. To reduce the model dimension and computational cost, the three-nucleon force is truncated at the normal-ordered two-body level and limited in the sd-shell model space, with the residual three-body term being neglected. We choose neutron-rich oxygen isotopes as the test ground because they have been well studied experimentally, with the neutron dripline determined. The calculations have been carried out within the Gamow shell model. The quality of our results in reproducing the properties of oxygen isotopes around the neutron dripline shows the relevance of the interplay between three-nucleon force and the coupling to continuum states. We also analyze the role played by the chiral three-nucleon force, by dissecting the contributions of the 2π exchange, 1π exchange and contact terms.
This paper discusses the derivation of an effective shell-model hamiltonian starting from a realistic nucleon–nucleon potential by way of perturbation theory. More precisely, we present the state of ...the art of this approach when the starting point is the perturbative expansion of the Qˆ-box vertex function. Questions arising from diagrammatics, intermediate-states and order-by-order convergences, and their dependence on the chosen nucleon–nucleon potential, are discussed in detail, and the results of numerical applications for the p-shell model space starting from chiral next-to-next-to-next-to-leading order potentials are shown. Moreover, an alternative graphical method to derive the effective hamiltonian, based on the Zˆ-box vertex function recently introduced by Suzuki et al., is applied to the case of a non-degenerate (0+2)ħω model space. Finally, our shell-model results are compared with the exact ones obtained from no-core shell-model calculations.
► The derivation of nuclear realistic shell-model effective hamiltonians is studied. ► Perturbation theory. ► Diagrammatics, intermediate-states and order-by-order convergences are investigated. ► Shell-model calculations in degenerate and non-degenerate model spaces are presented. ► Shell-model results are compared with the exact ones.
PDF
