Mussel-inspired Coating of α-AlH3: A Compact Structure with Highly Enhanced Stability

we present a novel surfacing coating to resolve the stability of α-AlH3. Inspired by the strong chemical adhesion of mussels, the polymerization of dopamine was first introduced to coat α-AlH3 through a simple situ polymerization. The α-AlH3 was used as a substrate. In-depth characterizations confirmed compact formation with PDA on α-AlH3 surface. The coated α-AlH3 sample was characterized by XRD XPS and SEM . The results show that a strong PDA film is formed on the surface of α-AlH3, the PDA@α-AlH3 retained primary morphology. The crystal form of α-AlH3 does not change after coated by PDA. The results of XPS analysis show that N1s appears on the material after coated by PDA, indicating that polydopamine is formed on the surface of α-AlH3. The moisture absorption tests show that the moisture absorption rate of α-AlH3 is greatly reduced after being coated with PDA. The excellent intact ability of PDA prevent α-AlH3 reacting with watered in the air. The thermal stability of α-AlH3 before and after coating was analyzed by DSC. This work demonstrates the successful applications of dopamine chemistry to α-AlH3, thereby providing a potential method for the metastable materials.

Thermal response of electronic, optical, mechanical properties, phonon frequencies, and sound velocity of InPxAsySb1-x-y/InAs quaternary semiconductor system

The temperature dependence of acoustic velocities, thermal properties, and phonon frequencies, mechanical, electronic, and optical properties for the InPxAsySb1-x-y/InAs system has been studied. The physical properties of the binary components InSb, InP, and InAs that constitute the quaternary alloy were used in this research. The study has been done using the empirical pseudo-potential method (EPM) under the virtual crystal approximation (VCA). The thermal properties, phonon frequencies, and acoustic velocities for the InPxAsySb1-x-y/InAs system under the effect of temperature have not been fully studied. Therefore, we have focused on these properties under the influence of temperature. Due to the lack of the published theoretical and experimental values on these properties, our findings will provide a significant reference for future experimental work.

Photocrosslinking of Adventitial Collagen in the Porcine Abdominal Aorta: A Preliminary Approach to a Strategy for Prevention of Aneurysmal Rupture

This study was aimed at generating data for designing a potential method to prevent the rupture of the abdominal aortic aneurysm (AAA). We found that the mechanical strength and stiffness of blood vessel walls was enhanced by the crosslinking of adventitial collagen through a photochemical process promoted by ultraviolet-A (UV-A) radiation. The experiments were carried out on samples isolated from 25 normal porcine aortas. The adventitial layer was separated from the other layers and exposed to UV radiation of 365-nm wavelength, in the presence of a riboflavin compound as the photosensitizer. Mechanical testing of 30 specimens, prior to and after exposure, indicated an increase in both strength (ultimate stress) and stiffness (Young’s modulus) of the adventitial specimens following irradiation. The crosslinking process also led to an enhanced resistance to experimental collagenolysis, as determined on six specimens. At this phase of conceptual design, we suggest that by applying this method to an aneurysmal dilated wall region, the stabilization of tunica adventitia may delay or prevent the rupture of the aneurysm and, with further investigation and refinement, can become a therapeutic strategy for arresting the progression of AAA.

Finite-Element Modeling of Spontaneous Potential in an Axisymmetric Reservoir Model with Account of Its Shale Content

(1) This article is devoted to the development of a theoretical and algorithmic basis for numerical modeling of the spontaneous potential method (SP) as applied to the study of sandy-argillaceous reservoirs. (2) In terms of coupled flows, we consider a physical–mathematical model of SP signals from an electrochemical source, with regards to the case of fluid-saturated shaly sandstone. (3) An algorithm for 2D finite-element modeling of SP signals was developed and implemented in software, along with its internal and external testing with analytical solutions. The numerical SP modeling was carried out, determining the dependences on the reservoir thickness and porosity, the amount of argillaceous material and the type of minerals. We performed a comparative analysis of the simulated and field SP data, using the results of laboratory core examinations taken from wells in a number of fields in the Latitudinal Ob Region of Western Siberia. (4) The results of the study may be used either for the development of the existing SP techniques, by providing them with a consistent computational model, or for the design of new experimental approaches.

Open holes in composite laminates with finite dimensions: structural assessment by analytical methods

Open circular holes are an important design feature, for instance in bolted joint connections. However, stress concentrations arise whose magnitude depends on the material anisotropy and on the defect size relative to the outer finite plate dimensions. To design both safe and light-weight optimal structures, precise means for the assessment are crucial. These can be based on analytical methods providing efficient computation. For this purpose, the focus of the present paper is to provide a comprehensive stress and failure analysis framework based on analytical methods, which is also suitable for use in industry contexts. The stress field for the orthotropic finite-width open-hole problem under uniform tension is derived using the complex potential method. The results are eventually validated against Finite-Element analyses revealing excellent agreement. Then, a failure analysis to predict brittle crack initiation is conducted by means of the Theory of Critical Distances and Finite Fracture Mechanics. These failure concepts of different modelling complexity are compared to each other and validated against experimental data. The size effect is captured, and in this context, the influence of finite width on the effective failure load reduction is investigated.

An evaluation of the capacitive behavior of supercapacitors as a function of the radius of cations using simulations with a constant potential method.

We report on the molecular dynamics atomistic applying the constant potential method to determine the structural and electrostatic interactions at the electrode-electrolyte interface of electrochemical supercapacitors as a function of...

Torrential Floods and Soil Erosion

Floods on large rivers and torrential floods are the most common natural disasters in the Republic of Serbia. Floods on rivers are natural phenomena that go far beyond the framework of water management and hydro-technical measures. Given the distribution of hilly and mountainous areas in the Republic of Serbia and the developed hydrographic network, torrential floods occur very often, almost every year. Torrential floods and soil erosion are inseparable natural phenomena that shaped the relief long before the appearance of living beings on Earth. Erosion processes are difficult to notice and slow and are most often noticed only when large areas are exposed, and then the problem of erosion becomes a difficult-to-solve or unsolvable problem. For the classification of erosion processes in the Republic of Serbia, the EPM method (erosion potential method) is used, which classifies erosion into five categories that have their own quantitative characteristics.

The effect of initial phase on the emission characteristics of forward electron colliding with a tightly focused linearly polarized few-cycle laser pulse

We have studied the high harmonic radiation property from the scattering of an electron with a focused few-cycle laser pulse by analyzing the distribution of the radiation field and the motion state of the electron. In the time domain, temporal width of the compressed radiation can reach 33 zs (zeptosecond), thus an ultrashort x-ray pulse was generated in the interaction process. The radiation in this process is vastly similar to high harmonic generation in the process of atomic strong-field. The latter depends to a large extent on the phase of carrier-envelope (CE) driving laser pulse. The cutoff of radiation spectrum can reach 1 × 10 5 ω 0 , and whether the high-order harmonic spectrum in the cut-off region can be well resolved depends on the CE phase. We have investigated the relationship between the maximum radiation intensity and the CE phase, and discussed a potential method to characterize the CE phase of an intense few-cycle laser pulse for broader application prospects.