Emergency Separation Simulation and Damage Prediction of an Airliner under Wheel-Up Landing Condition

To predict the damage to and response of aircraft structures during wheel-up crash landing, numerical simulations were performed using a constitutive and damage model for ductile metallic materials developed in the ABAQUS/Explicit environment. The model of an entire aircraft and detailed submodels were established. The Johnson–Cook and Gurson material constitutive models were validated by conducting Hopkinson’s bar test. A drop hammer test and a static test of the fuse pins were performed to determine and verify the response and strength of the structure. The experimental and analytical results indicate that the stain rate and damage parameters significantly influence the emergency separation load, fuse pin strength, and separation sequence. The analysis results were compared with the test results, and a close agreement was found in terms of the maximum load and deformation.

Intrinsically disordered protein regions and phase separation: sequence determinants of assembly or lack thereof

Intrinsically disordered protein regions (IDRs) — regions that do not fold into a fixed three-dimensional structure but instead exist in a heterogeneous ensemble of conformations — have recently entered mainstream cell biology in the context of liquid–liquid phase separation (LLPS). IDRs are frequently found to be enriched in phase-separated compartments. Due to this observation, the presence of an IDR in a protein is frequently assumed to be diagnostic of its ability to phase separate. In this review, we clarify the role of IDRs in biological assembly and explore the physical principles through which amino acids can confer the attractive molecular interactions that underlie phase separation. While some disordered regions will robustly drive phase separation, many others will not. We emphasize that rather than ‘disorder' driving phase separation, multivalency drives phase separation. As such, whether or not a disordered region is capable of driving phase separation will depend on the physical chemistry encoded within its amino acid sequence. Consequently, an in-depth understanding of that physical chemistry is a prerequisite to make informed inferences on how and why an IDR may be involved in phase separation or, more generally, in protein-mediated intermolecular interactions.

Selection of Optimum Separation Sequence for Multicomponent Distillation

This paper considers the process of multicomponent distillation. It is shown that energy consumption (per mole of mixture being separated) depends monotonously on efficiency if the capacity is constant and separation is reversible. Authors suggest the technique for selection of distillation sequence for which the total energy consumption in the cascade of columns reaches its minimum. This sequence is determined by values of thermal coefficients. Coefficients themselves depend on temperatures in the reboiler and condenser. This paper offers the algorithm for the calculation of these coefficients.

Optimization of Distillation Sequences with Nonsharp Separation Columns

Nonsharp distillation sequences are widely used in industrial separation processes; however, most current research has not discussed this topic, except in sequences with heat integration under special operating conditions, including complex columns. The sequence with nonsharp separation has the features of general distillation sequences, which are usually optimized by adjusting the separation sequence and the design/operation parameters of each column in the sequence, making the optimization a mixed integer nonlinear programming (MINLP) problem, which is usually hard to solve. With inclusion of nonsharp separation columns, the sequence optimization becomes even more complicated and computationally intensive. This work aimed to optimize the distillation sequence, including nonsharp distillation alongside simple columns and dividing wall columns. Inspired by the dynamic programing method for sharp distillation sequence, a framework for automatic optimization is proposed to decompose the MINLP problem into integer programming (IP) and nonlinear programming (NLP) problems. The optimization processes of sharp and nonsharp distillation sequences are compared and the solution space in terms of the possible number of distillation sequences with nonsharp separation is discussed. Two optimization cases, including an industrial one, are included to validate the proposed framework.

Continuous generation, in-line quantification and utilization of nitrosyl chloride in photonitrosation reactions

The reagent is prepared from stable, inexpensive and readily available starting materials. In-line UV/vis monitoring enables determination of the reagent's concentration after a continuous extraction and liquid–liquid separation sequence.

The Rule of Temperature Coefficients for Selection of Optimal Separation Sequence for Multicomponent Mixtures in Thermal Systems

In this paper an estimate for the reversible molar heat supply needed for fully separating a certain mixture is given on the basis of thermodynamic balance equations. It is shown that in order to estimate this heat supply one should solve the problem of selecting the optimal separation sequence. The algorithm solving this task is given. This algorithm allows to select the separation sequence on the basis of preliminary calculations, knowing only the properties of the component that one wants to separate. The solution algorithm is demonstrated for an exemplary system: a gas-fractionation plant.