In-plane and shear buckling analysis of FG-CNTRC annular sector plates based on the third-order shear deformation theory using a numerical approach

The buckling analysis of thick composite annular sector plates reinforced with functionally graded carbon-nanotubes (CNTs) is presented under in-plane and shear loadings based on the higher-order shear deformation theory. It is considered that the plate is resting on the Pasternak-type elastic foundation. The overall material properties of functionally graded carbon nanotube-reinforced composites (FG-CNTRCs) are estimated through the micromechanical model. The governing equations are derived on the basis of the higher-order shear deformation plate theory, and the quadratic form of the energy functional of the system is presented. An efficient numerical method is presented in the context of variational formulation to obtain the discretized version of stability equations. The validation of the present study is demonstrated through comparisons with the results available in the literature and then comprehensive numerical results are given to investigate the impacts of model parameters on the stability of CNT-reinforced composite annular sector plates.     

The influence of build strategies in selective inhibition sintering (SIS)

Selective Inhibition Sintering of metal alloys (SIS-metal) has been proven effective in the additive manufacture (AM) of low resolution bronze parts. Recent advancements in the use of a high-precision inkjet print head represented an order of magnitude improvement in SIS-metal resolution. However, the fabrication of complex three-dimensional metallic parts required new SIS-metal compatible, cross-sectional image generation based on the part boundary profile. In the proposed study, five candidate layer-processing approaches were identified and validated for basic geometries. These approaches were chosen from previous research as well as preliminary investigations and were applied to a modified SIS-metal process for validation. The validation criteria were based upon the amount of powder waste produced, the ability to handle complex geometries, printing speed, extraction (post-processing) speed, and part integrity. Results are discussed for implementation of the five candidate layer processing approaches in the fabrication of basic shapes. A preliminary evaluation is presented for their use on more complex geometries. Two approaches were then chosen for the construction of more complex geometries, the results of which are presented.     

In situ synthesis of Al2O3‐supported ZnCr2O4 nanoparticles for application as an activated photocatalyst

Zincochromite nanoparticles (NPs) were precipitated on surfaces of the as‐prepared Al₂O₃ micron‐sized particles by a heterogeneous precipitation technique using urea as a homogeneous precipitation agent. This procedure leads to decrease the pore diameter and increase the pore volume and specific surface area (a_s), realizing the potential access to ZnCr₂O₄ catalytic sites. Although the obtained band gap energy (E_g) of Al₂O₃‐ZnCr₂O₄ composite is about 2.3 eV (more than ZnCr₂O₄), the absorbance is enhanced about 1.5 orders of magnitude. These characteristics make it an effective photocatalyst of inorganic dyes from an aqueous media. Dye removal performance of the nanocomposite powder is higher than that of pure ZnCr₂O₄, which is attributed to an increase in the photocatalytic sites and the absorbance intensity. It was believed that the surface area created from Al₂O₃ support realized the potential access to ZnCr₂O₄ catalytic sites. To confirm these assertions, X‐ray diffractometry (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), and N₂ adsorption‐desorption analysis were applied.     

Effect of Calculation Method on Values of Hansen Solubility Parameters of Polymers

Summary The simplest experimental method to determine the Hansen Solubility Parameters (HSP) for a polymer is to evaluate whether or not it dissolves in selected solvents. The solvents dissolve the polymer have HSP closer to it than those which don’t. Then a computer program can be used to find the HSP of the selected polymer. In this work, the effect of calculation method on the values of HSP has been analyzed completely. The results show that optimization method for calculation of HSP is an important factor in the precision of obtained values of these parameters.     

Sudden Fracture from U-Notches in Fine-Grained Isostatic Graphite Under Mixed Mode I/II Loading

The U-notched maximum tangential stress (UMTS) criterion, proposed originally and utilized previously by the author and his co-researcher for predicting mixed mode I/II fracture in plexi-glass (PMMA) and also pure mode II fracture in PMMA and soda-lime glass, was employed to estimate the experimental results reported in literature dealing with brittle fracture of many U-notched fine-grained isostatic graphite plates under combined tensile/shear loading conditions. By using the fracture curves of the UMTS criterion, which can predict the onset of brittle fracture in terms of the notch stress intensity factors (NSIFs) in the entire domain from pure mode I to pure mode II, the mixed mode fracture toughness (i.e. the load-bearing capacity) of U-notched graphite plates was successfully estimated.     

Extended beam search for non-exhaustive state space analysis

State space explosion is a major problem in both qualitative and quantitative model checking. This article focuses on using beam search, a heuristic search algorithm, for pruning weighted state spaces while generating. The original beam search is adapted to the state space generation setting and two new variants, motivated by practical case studies, are devised. These beam searches have been implemented in the μCRL toolset and applied on several case studies reported in the article.