The functionalization of tetrathienoanthracene (TTA) with bromine and 2-hexylthiophene moieties is described, and their influence at both the molecular and solid-state level has been investigated. Comparative optical and electrochemical studies indicate an increase in conjugation for the thiophene derivative compared to the parent TTA. In the solid state, these materials form slipped π-stack structures with a number of close intermolecular contacts. Comparison of the two structures reveals a more steeply inclined slipped π-stack for the thiophene derivative resulting in a closer interplanar separation. This, coupled with the extended molecular framework, leads to an enhanced number of π−π interactions within the stack. The combination of increased conjugation at the molecular level, and π-stacked structures with strong intermolecular communication at the solid-state level, augurs well for the use of TTA materials in optoelectronic applications.
A novel injectable composite hydrogel based on chitosan and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) reinforced with nanohydroxyapatite particles was synthesized. The chemical structure and morphology of the composite hydrogel were characterized. The composite hydrogel porosity, swelling, mechanical properties, viscoelasticity and in vitro biodegradation were also examined. Compared with the non-reinforced hydrogel, the composite hydrogel showed increased compressive strength, elastic modulus, viscous modulus, stiffness and had shear-thinning behaviour proving the injectability of the system. Swelling and biodegradation studies revealed that the composite scaffold possesses proper hydrophilicity and biodegradability. These properties make this composite hydrogel a promising injectable scaffold for bone regeneration.
Construction projects are often challenged by tight budgets and limited time and resources. Contractors are, therefore, looking for ways to become competitive by improving efficiency and using cost-effective materials. Using three-dimensional (3D) printing for shaping materials to produce cost-effective construction elements is becoming a feasible option to make contractors more competitive locally and globally. The process capabilities for 3D printers and related devices have been tightened in recent years with the booming of 3D printing industries and applications. Contractors are attempting to improve production skills to satisfy firm specifications and standards, while attempting to have costs within competitive ranges. The aim of this research is to investigate and test the production process capability (Cp) of 3D printers using fused deposition modeling (FDM) to manufacture 3D printed parts made from plastic waste for use in the construction of buildings with different infill structures and internal designs to reduce cost. This was accomplished by calculating the actual requirement capabilities of the 3D printers under consideration. The production capabilities and requirements of FDM printers are first examined to develop instructions and assumptions to assist in deciphering the characteristics of the 3D printers that will be used. Possible applications in construction are then presented. As an essential outcome of this study, it was noticed that the 3D printed parts made from plastic waste using FDM printers are less expensive than using traditional lightweight non-load bearing concrete hollow masonry blocks, hourdi slab hollow bocks, and concrete face bricks.
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