A low-cost multiscale model with fiber/matrix interface for cryogenic composite storage tanks considering temperature effects based on self-consistent clustering analysis

Matrix (including interface) failure is a typical form of failure in the composite laminates for cryogenic storage tanks causing functionally useless of the structure. In this work, a low-cost multiscale model based on the Self-consistent Clustering Analysis (SCA) method is developed to predict the matrix failure process of the composite storage tanks. First, a reduced order model modeling method with fiber/matrix interfaces is proposed. Then, in conjunction with Progressive Failure Analysis (PFA), a reduced-order model is used to predict matrix failure and interface failure of the composites, mesh sensitivity analyses were carried out, and strength damage envelopes were obtained for unidirectional composites subjected to a combination of transverse stresses and in-plane shear. Compared with the prediction results of the Puck criterion, the errors in predicting damage strength for compressive-shear load and tensile-shear load do not exceed 10% and 30%, respectively. And finally, the thermal-mechanical load analysis of the composite storage tanks is carried out and the effect of homogenous temperature field and heterogenous temperature field on the load-bearing performance of the composite structure is analyzed. The method is proved to have good accuracy and to be very efficient. Its main feature is the ability to rapidly predict the stiffness and strength properties of composite structures under different environmental conditions, in agreement with experimental results, showing the potential to reduce the time and cost required for structural design.</p

Comparison of OS, DFS, RFS between zoledronic acid therapy and control.

<p>Comparison of OS, DFS, RFS between zoledronic acid therapy and control.</p

Summary of LF-induced SNHL case studies.

<p>Summary of LF-induced SNHL case studies.</p

Summary of the relative risks of all outcomes assessed.

<p>Summary of the relative risks of all outcomes assessed.</p

Subgroup analysis for the effect of zoledronic acid therapy on total death, disease recurrence, and fracture.

<p>Subgroup analysis for the effect of zoledronic acid therapy on total death, disease recurrence, and fracture.</p

Mechanistic Insights into the Cu(I)- and Cu(II)-Catalyzed Cyclization of <i>o</i>‑Alkynylbenzaldehydes: The Solvent DMF and Oxidation State of Copper Affect the Reaction Mechanism

A computational study with the BhandHLYP density functional is conducted to elucidate the mechanisms of Cu­(I)- and Cu­(II)-catalyzed reactions of <i>o</i>-alkynylbenzaldehydes with a nucleophile (MeOH). Our calculations suggest the following. (a) The use of CuCl as a catalyst deceases significantly the energy barrier and promotes intramolecular cyclization. (b) Solvent DMF is critical in the stepwise hydrogen-transport process involved in an intermolecular nucleophilic addition because it can greatly reduce the free energy barrier of the hydrogen-transfer process as a proton shuttle. In addition, we find that substrate MeOH also plays a role similar to that of DMF in the hydrogen-transport reaction. (c) The 6-endo product P1 is formed exclusively using a catalytic system consisting of CuCl and DMF, whereas a mixture of 6-endo product P1 and 5-exo product P2 in a ratio of ∼1:1 is produced using CuCl₂ and DMF as a catalytic system. Our theoretical calculations reproduce the experimental results very well. This study is expected to improve our understanding of Cu­(I)- and Cu­(II)-catalyzed reactions involving Lewis base solvents and to provide guidance for the future design of new catalysts and new reactions

Effect of ammonia solution concentration on the measured element.

Effect of ammonia solution concentration on the measured element.</p

Determination results of national standard references of soils.

Determination results of national standard references of soils.</p

Working parameters of ICP OES.

To overcome the corrosion of hydrofluoric acid on the ICP OES injection system in the acid dissolution system, this paper makes some improvements based on the traditional open digestion. The improved method does not require the complete removal of hydrofluoric acid. After appropriate digestion of the sample with a mixed acid, the solution can be transferred to a colorimetric tube containing ammonium hydroxide solution to give the final volume for analysis. In this paper, two-point standard curves are plotted using soil standards and process blanks, which is not only convenient but also overcomes the interference of the matrix effect. Through continuous experiments, the preferred ratio of mixed acid is 3 mL nitric acid + 5 mL hydrofluoric acid, and the concentration of ammonia solution is 0.5%. The spectral lines of the measured elements V (292.4), Cr (283.5), Co (228.6), Ni (231.6), Cu (324.7), Zn (213.8) and Pb (220.3) were determined. The method quantification limits of the seven measured elements V, Cr, Co, Ni, Cu, Zn and Pb were 0.909, 4.32, 0.269, 0.261, 0.968, 3.69 and 2.64 μg g-1, respectively, and the precision was 3.5%, 5.2%, 4.8%, 2.4%, 6.1% and 4.5%, respectively. After processing six national standard materials according to the experimental method, the measured values of each measured element were basically in agreement with the certified values, indicating that this method is fully feasible for the measurement of V, Cr, Co, Ni, Cu, Zn and Pb in soil. This method greatly improves the efficiency of pretreatment and is particularly suitable for analysing large batches of samples.</div