Fabrication and characterization of PLA/PP/ABS ternary blend

In this study, we fabricated and studied properties of ternary polymer blends containing polylactic acid (PLA), polypropylene (PP), and acrylonitrile‐butadiene‐styrene (ABS). The melt rheology experiments showed that the present combination (PLA/PP/ABS) exhibited a melt process‐ability, which is comparable to those of individual components. The ternary blends prepared in this work can be exploited to fabricate hierarchically porous PLA materials for biomedical applications. POLYM. ENG. SCI., 59:2273–2278, 2019. © 2019 Society of Plastics Engineers     

Studies on Preparation and Hydrogen Storage Properties of Dual-Metal Ferrocenyl Coordination Polymer Microspheres

A series of dual-metal ferrocenyl coordination polymer microspheres (M₁M₂-CPMs, M₁M₂ = CoMn, CoCu, MnCu) were synthesized by the reaction of 1,1′-ferrocene dicarboxylic acid with mixed metal salts via solvothermal method. From SEM and TEM images, it was found that all the as-synthesized coordination polymers showed microspheres structures. The products were also characterized by X-ray photoelectron spectroscopy (XPS), fourier transform infrared (FT-IR), powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA). The M₁M₂-CPMs showed good thermostability and remained stable up to 250 °C. These M₁M₂-CPMs exhibited hydrogen uptake capacity. More interestingly, through the comparison among three microspheres we found that the M₁M₂-CPMs with hollow structures showed better hydrogen uptake.     

Multi-scale pharmaceutical process understanding: From particle to powder to dosage form

Understanding the properties and behavior of pharmaceutical materials is critical to the design of a safe and effective dosage form. The desired performance of pharmaceutical products differs from other areas of engineered material products. With pharmaceutical products, there is an increased level of importance on solubility, dissolution and stability; while a secondary level of importance is given to mechanical properties. The use of multi-scale process understanding suggests incorporating data from the different scales (particle, powder, and dosage form) into a single informatics database. The properties of the active pharmaceutical ingredient and the excipients must be interrogated at each scale. At the particle level, the primary concerns are with solubility, dissolution rate, the anisotropic properties of pharmaceutical crystals, polymorphism and the degree of crystallinity. At the level of the powder scale, the primary concerns are powder flow and the ability of the bulk powder to be compacted into a dosage form. Finally, at the dosage form level, critical issues include the effect of excipient crystallinity on dosage form dissolution rate and the tensile strength of compacts made from milled, roller compacted ribbons. Examples of existing and emerging approaches for understanding these properties and behaviors at each scale are illustrated as key elements in developing a multi-scale process understanding of a pharmaceutical process.     

Surface morphology and chemistry of epoxy-based coatings after exposure to ultraviolet radiation

The effects of ultraviolet (UV) radiation on the surface morphology and the surface chemistry of an epoxy-resin-based coating were characterized with both scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The techniques were applied to follow the chemical changes that occur after different UV-exposure periods.     

Pulicaria glutinosa Extract: A Toolbox to Synthesize Highly Reduced Graphene Oxide-Silver Nanocomposites

A green, one-step approach for the preparation of graphene/Ag nanocomposites (PE-HRG-Ag) via simultaneous reduction of both graphene oxide (GRO) and silver ions using Pulicaria glutinosa plant extract (PE) as reducing agent is reported. The plant extract functionalizes the surfaces of highly reduced graphene oxide (HRG) which helps in conjugating the Ag NPs to HRG. Increasing amounts of Ag precursor enhanced the density of Ag nanoparticles (NPs) on HRG. The preparation of PE-HRG-Ag nanocomposite is monitored by using ultraviolet–visible (UV-Vis) spectroscopy, powder X-ray diffraction (XRD), and energy dispersive X-ray (EDX). The as-prepared PE-HRG-Ag nanocomposities display excellent surface-enhanced Raman scattering (SERS) activity, and significantly increased the intensities of the Raman signal of graphene.     

Multiple Pedestrian Detection and Tracking in Night Vision Surveillance Systems

Pedestrian detection and tracking are vital elements of today’s surveillance systems, which make daily life safe for humans. Thus, human detection and visualization have become essential inventions in the field of computer vision. Hence, developing a surveillance system with multiple object recognition and tracking, especially in low light and night-time, is still challenging. Therefore, we propose a novel system based on machine learning and image processing to provide an efficient surveillance system for pedestrian detection and tracking at night. In particular, we propose a system that tackles a two-fold problem by detecting multiple pedestrians in infrared (IR) images using machine learning and tracking them using particle filters. Moreover, a random forest classifier is adopted for image segmentation to identify pedestrians in an image. The result of detection is investigated by particle filter to solve pedestrian tracking. Through the extensive experiment, our system shows 93% segmentation accuracy using a random forest algorithm that demonstrates high accuracy for background and roof classes. Moreover, the system achieved a detection accuracy of 90% using multiple template matching techniques and 81% accuracy for pedestrian tracking. Furthermore, our system can identify that the detected object is a human. Hence, our system provided the best results compared to the state-of-art systems, which proves the effectiveness of the techniques used for image segmentation, classification, and tracking. The presented method is applicable for human detection/tracking, crowd analysis, and monitoring pedestrians in IR video surveillance.     

Shape-Memory Photonic Thermoplastics from Cellulose Nanocrystals

Responsive materials prepared using shape-memory photonic crystals have potential applications in rewritable photonic devices, security features, and optical coatings. By embedding chiral nematic cellulose nanocrystals (CNCs) in a polyacrylate matrix, a shape-memory photonic crystal thermoplastic (CNC-SMP) allows reversible capture of different colored states is reported. In this system, the temperature is used to program the shape-memory response, while pressure is used to compress the helical pitch of the CNC chiral nematic organization. By increasing the force applied ( ≈ 140–230 N), the structural color can be tuned from red to blue. Then, on-demand, the CNC-SMP can recover to its original state by heating it above the glass transition temperature. This cycle can be performed over 15 times without any loss of the shape-memory behavior or mechanical degradation of the sample. In addition, multicolor readouts can be programmed into the chiral nematic CNC-SMP by using a patterned substrate to press the sample, while the glass transition temperature of the CNC-SMP can be tuned over a 90  ° C range by altering the monomer composition used to prepare the polyacrylate matrix.     

Recent progress in multiphase flow simulation through multiphase pumps

The multiphase flow pumps cover a wide range of industrial sectors extending across petrochemical, metallurgy, and dredging, chemical industry, paint, and construction. The major application is the handling of wet gas and vapor that will condense partially during the compression stage. The main progress in the area of multiphase pumps has been the innovation of a computational fluid dynamics (CFD) numerical approach to simulate three‐dimensional flows inside the pump and to predict pump performance. CFD undoubtedly constitutes one of the most promising approaches for the design, analysis, and performance assessment of complex machines. However, practical application of the CFD tool to determine the internal flow field in multiphase pumps is still far from reality owing to the limitations of a detailed three‐dimensional model of the pump and accuracy of multiphase flow simulation. This review accentuates the influence of different geometrical and dynamical parameters on the performance of the pump and the use of CFD simulation to predict the detailed flow patterns of fluid mixtures. CFD analysis has unearthed the fact that the pattern of inner flow varies with the flow rate and concentration of each phase and the rotation speed of the impeller and number of blades were also found to considerably impact pump performance.     

Retrieving the Coassembly Pathway of Composite Cellulose Nanocrystal Photonic Films from their Angular Optical Response

Aqueous suspensions of cellulose nanocrystals (CNCs) are known to self-assemble into a chiral nematic liquid crystalline phase, leading to solid-state nanostructured colored films upon solvent evaporation, even in the presence of templating agents. The angular optical response of these structures, and therefore their visual appearance, are completely determined by the spatial arrangement of the CNCs when the drying suspension undergoes a transition from a flowing and liquid crystalline state to a kinetically arrested state. Here, it is demonstrated how the angular response of the final film allows for retrieval of key physical properties and the chemical composition of the suspension at the onset of the kinetic arrest, thus capturing a snapshot of the past. To illustrate this methodology, a dynamically evolving sol–gel coassembly process is investigated by adding various amounts of organosilica precursor, namely, 1,2-bis(trimethoxysilyl)ethane. The influence of organosilica condensation on the kinetic arrest can be tracked and thus explains the angular response of the resulting films. The a posteriori and in situ approach is general; it can be applied to a variety of additives in CNC-based films and it allows access to key rheological information of the suspension without using any dedicated rheological technique.