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The objective of the present study is to evaluate the hot tearing tendency based on the Clyne and Davies model by evaluating the critical times which can be obtained using a newly developed method. A method to determine the critical times required to calculate the crack susceptibility was presented based on the measurement results with Al–Si alloys, and the method to calculate the crack susceptibility coefficient was presented. In the newly developed method named “Signal intensity method,” signals were generated by tapping the edge of a waveguide which is immersed in molten and solidifying sample and the critical solid fractions were obtained from the signal intensity change. The conventional thermal analysis was also performed simultaneously and the corresponding critical points were identified. The method shown in the present study will enable the determination of the crack susceptibility coefficient with higher accuracy.

Halide perovskite light-emitting diodes (PLEDs) have raised considerable attention due to their high color purity and rapid development performance. Although high-efficiency PLEDs have been continuously and repeatedly reported, the lack of a highly reproducible manufacturing process for PLEDs hinders their future development and commercialization. Here, a generic protocol for rational control of the nucleation and crystallization process of the perovskite emission layer is reported. Through the monitoring of the photoluminescence during spin-coating, the antisolvent dripping time can be precisely determined. Therefore, it is possible to repeatedly produce a perovskite emission layer with high PLQY, smooth surface/interface, and good homogeneity. As a result, high-performance PLEDs are easily obtained. Moreover, the standard deviation of the fabricated PLEDs performance is smaller than 0.8%, showing high reproducibility independent of the process conditions such as the process temperature, solvent atmosphere, and spin-coating parameters, which highlights the statement of the importance of rationally control of the antisolvent process. The methodology provides important progress towards highly reproducible manufacturing of PLEDs for practical applications. © 2021 Wiley-VCH GmbH

Halide perovskite light-emitting diodes (PLEDs) have raised considerable attention due to their high color purity and rapid development performance. Although high-efficiency PLEDs have been continuously and repeatedly reported, the lack of a highly reproducible manufacturing process for PLEDs hinders their future development and commercialization. Here, a generic protocol for rational control of the nucleation and crystallization process of the perovskite emission layer is reported. Through the monitoring of the photoluminescence during spin-coating, the antisolvent dripping time can be precisely determined. Therefore, it is possible to repeatedly produce a perovskite emission layer with high PLQY, smooth surface/interface, and good homogeneity. As a result, high-performance PLEDs are easily obtained. Moreover, the standard deviation of the fabricated PLEDs performance is smaller than 0.8%, showing high reproducibility independent of the process conditions such as the process temperature, solvent atmosphere, and spin-coating parameters, which highlights the statement of the importance of rationally control of the antisolvent process. The methodology provides important progress towards highly reproducible manufacturing of PLEDs for practical applications. © 2021 Wiley-VCH GmbH

Halide perovskite light-emitting diodes (PLEDs) have raised considerable attention due to their high color purity and rapid development performance. Although high-efficiency PLEDs have been continuously and repeatedly reported, the lack of a highly reproducible manufacturing process for PLEDs hinders their future development and commercialization. Here, a generic protocol for rational control of the nucleation and crystallization process of the perovskite emission layer is reported. Through the monitoring of the photoluminescence during spin-coating, the antisolvent dripping time can be precisely determined. Therefore, it is possible to repeatedly produce a perovskite emission layer with high PLQY, smooth surface/interface, and good homogeneity. As a result, high-performance PLEDs are easily obtained. Moreover, the standard deviation of the fabricated PLEDs performance is smaller than 0.8%, showing high reproducibility independent of the process conditions such as the process temperature, solvent atmosphere, and spin-coating parameters, which highlights the statement of the importance of rationally control of the antisolvent process. The methodology provides important progress towards highly reproducible manufacturing of PLEDs for practical applications. © 2021 Wiley-VCH GmbH

Boron compounds are effective ingredients, widely used in passive fire protection. In this work, epoxy-based hydrocarbon intumescent coatings, containing one of three boron compounds, zinc borate (ZB), ammonium pentaborate (APB), and boric acid (BA), were compared in thermal insulation performance at UL1709 heating conditions, char morphology, viscoelastic behavior, thermal degradation, and composition of the char surface layer. Results show that the char structure provides the most reliable indication of the thermal insulation performance. For APB- and BA-containing coatings, results were similar, while the ZB-containing ones showed a distinctive performance, especially the ones with the high borate concentration. The latter was attributed to the role of ZB in the intumescence and oxidation reactions, where the zinc, in the presence of boron, led to a compact char with less oxidation and high residual mass. In the char surface layer of one sample with a high concentration of ZB, a crystalline phase of boron trioxide, anticipated to be one important origin of the compact char, was detected. The present work contributes with an understanding of the essential roles of boron compounds, as well as the binder and pigment contents, and provides guidelines for seeking more sustainable and environmentally friendly alternatives.

Highlights - Investigate time for morphogen gradient to effectively reach steady state. - Analyse both the concentration profile and the gradient of the concentration profile. - For typical problem, the gradient effectively reaches steady state faster. Abstract We extend some recent analysis regarding an approximation of the time scale required for a transient morphogen concentration profile to approach steady state. Motivated by experimental observations, we consider the time scale required for the spatial gradient of morphogen concentration to approach steady state. The analysis shows that the spatial gradient approaches steady state faster than the associated concentration profile approaches steady state. For typical parameter values, this difference in time scales appears to be significant because it is comparable to the time scale of a typical experiment.

The mean action time is the mean of a probability density function that can be interpreted as a critical time, which is a finite estimate of the time taken for the transient solution of a reaction-diffusion equation to effectively reach steady state. For high-variance distributions, the mean action time under-approximates the critical time since it neglects to account for the spread about the mean. We can improve our estimate of the critical time by calculating the higher moments of the probability density function, called the moments of action, which provide additional information regarding the spread about the mean. Existing methods for calculating the nth moment of action require the solution of n nonhomogeneous boundary value problems which can be difficult and tedious to solve exactly. Here we present a simplified approach using Laplace transforms which allows us to calculate the nth moment of action without solving this family of boundary value problems and also without solving for the transient solution of the underlying reaction-diffusion problem. We demonstrate the generality of our method by calculating exact expressions for the moments of action for three problems from the biophysics literature. While the first problem we consider can be solved using existing methods, the second problem, which is readily solved using our approach, is intractable using previous techniques. The third problem illustrates how the Laplace transform approach can be used to study coupled linear reaction-diffusion equations.

In 1991, McNabb introduced the concept of mean action time (MAT) as a finite measure of the time required for a diffusive process to effectively reach steady state. Although this concept was initially adopted by others within the Australian and New Zealand applied mathematics community, it appears to have had little use outside this region until very recently, when in 2010 Berezhkovskii and coworkers rediscovered the concept of MAT in their study of morphogen gradient formation. All previous work in this area has been limited to studying single–species differential equations, such as the linear advection–diffusion–reaction equation. Here we generalise the concept of MAT by showing how the theory can be applied to coupled linear processes. We begin by studying coupled ordinary differential equations and extend our approach to coupled partial differential equations. Our new results have broad applications including the analysis of models describing coupled chemical decay and cell differentiation processes, amongst others.

Heat and mass transport through multiple layers has applications to a wide range of areas, including industrial, geological, and medical problems. An important aspect of multilayer transport is the phenomenon of `critical time', which is a measure of how long the diffusive process takes. For example, how long until the coldest point of a steel coil reaches the annealing temperature during heating? The goals of this thesis are to: 1. explore the effect of layered structures on the critical time, thus demonstrating the limitations of the traditional averaging method for multilayer diffusion. 2. find simple approximate expressions of critical time that accurately reflect the multilayer behaviour, for both diffusion and reaction diffusion processes. 3. conduct a thorough comparison of prominent definitions currently in the literature, in particular finding when they are equivalent. 4. determine an averaging method which simplifies the multilayer reaction diffusion model to an analogous single layer system.In this thesis, an exact solution for multilayer diffusion is used to demonstrate the limitations of traditional averaging methods, which are only accurate for a large number of layers or in the steady state. The averaging method does not capture the asymmetric behaviour of the multilayer system. The exact solution is used to find elegant approximations for seven definitions of critical time, which accurately capture the multilayer behaviour. Each critical time definition is appropriate for different physical applications, with the most important difference being whether the definition is spatially dependent or independent. A thorough comparison between the critical time definitions is conducted. Reaction diffusion processes are considered, with the focus on a linear reaction function. An exact multilayer solution is found for a constant reactivity in all layers, which is then used to explore three critical time definitions. The outcome of the analysis is a simple, nov

A mathematical model of calculating the content of carboxyhaemoglobin in the blood of humans exposed to CO has been proposed. Results of comparing the calculation of carboxyhaemoglobin content with the experimental data of human exposure to constant concentration of CO during quiet breathing have been obtained. Results of numerical experiments for determining carboxyhaemoglobin concentration in case of rapid pulmonary ventilation that is characteristic for fire conditions in a room have been shown. The estimates of intervals of CO influence on the human body have been obtained with the use of the analytic solution of the integral model for calculating thermogasdynamics of fire. Critical fire durations obtained with the use of the proposed model and the traditional approach have been compared. It has been shown that the method of calculating the critical fire duration in terms of CO that exists in the scientific and regulatory literature on fire safety can lead to qualitatively and quantitatively incorrect results. © 2017 International Information Institute.