Polycarbonate‐based composites reinforced by in situ polytetrafluoroethylene fibrillation: Preparation,thermal and rheological behavior

Fibrillar reinforced composites of polytetrafluoroethylene (PTFE) and polycarbonate (PC) were prepared by in situ fibrillation of PTFE into PC matrix using twin screw extruder. Different samples were obtained by varying the relative ratio between PC and PTFE. The rheological properties of the PC/PTFE composites were found to depend on concentration of the PTFE fibrils. The melt strength analysis in nonisothermal conditions was also studied. The increase in force and decrease in drawability with increasing the PTFE content are associated with the PTFE fibrils formed in situ during the thermomechanical process in twin screw extruder. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42401.     

Magnetic resonance image denoising using nonlocal maximum likelihood paradigm in DCT‐framework

The data acquired by magnetic resonance (MR) imaging system are inherently degraded by noise that has its origin in the thermal Brownian motion of electrons. Denoising can enhance the quality (by improving the SNR) of the acquired MR image, which is important for both visual analysis and other post processing operations. Recent works on maximum likelihood (ML) based denoising shows that ML methods are very effective in denoising MR images and has an edge over the other state‐of‐the‐art methods for MRI denoising. Among the ML based approaches, the Nonlocal maximum likelihood (NLML) method is commonly used. In the conventional NLML method, the samples for the ML estimation of the unknown true pixel are chosen in a nonlocal fashion based on the intensity similarity of the pixel neighborhoods. Euclidean distance is generally used to measure this similarity. It has been recently shown that computing similarity measure is more robust in discrete cosine transform (DCT) subspace, compared with Euclidean image subspace. Motivated by this observation, we integrated DCT into NLML to produce an improved MRI filtration process. Other than improving the SNR, the time complexity of the conventional NLML can also be significantly reduced through the proposed approach. On synthetic MR brain image, an average improvement of 5% in PSNR and 86%reduction in execution time is achieved with a search window size of 91 × 91 after incorporating the improvements in the existing NLML method. On an experimental kiwi fruit image an improvement of 10% in PSNR is achieved. We did experiments on both simulated and real data sets to validate and to demonstrate the effectiveness of the proposed method. © 2015 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 25, 256–264, 2015     

Empowering Communities Through Design

Francesca Galeazzi is an architectural engineer who leads the sustainability team at Arup Associates in Shanghai. Here she looks back with hindsight from 2050, reflecting on how rapid urbanisation in China, which started in the 1990s, played out over the next half-century. She describes how the initial highly centralised, mass urbanisation programmes gave way to a more local and community-based, participatory approach to decision-making and planning, foreshadowed by some key legislation around land ownership and design for community-based planning models in the early 2010s.     

“Virtual Design Studio”—Part 1: Interdisciplinary design processes

The “Virtual Design Studio (VDS)” is a software platform currently under development in support of an integrated, coordinated and optimized design of buildings and their energy and environmental systems. It is intended to assist collaborating architects, engineers and project management team members throughout from the early phases to the detailed building design development. The platform helps to facilitate the workflow and the processing of information in combination with appropriate, task-based performance simulation tools as further analyzed in Part 2 of this study (DOI: 10.1007/s12273-013-0111-1). The present paper summarizes how VDS relates to the building design process and its typical project stages, performance-based design considerations and respective performance optimization strategies. It outlines the methodology and scope for the organization, implementation and respective requirements for the VDS platform development based on the interdisciplinary design needs. Part 2 will present the methodology for the systems integration and software implementation of VDS.     

Assessing the aggregation behaviour of iron oxide nanoparticles under relevant environmental conditions using a multi-method approach

Iron nanoparticles are becoming increasingly popular for the treatment of contaminated soil and groundwater; however, their mobility and reactivity in subsurface environments are significantly affected by their tendency to aggregate. Assessing their stability under environmental conditions is crucial for determining their environmental fate. A multi-method approach (including different size-measurement techniques and the DLVO theory) was used to thoroughly characterise the behaviour of iron oxide nanoparticles (Fe₂O₃NPs) under environmentally relevant conditions. Although recent studies have demonstrated the importance of using a multi-method approach when characterising nanoparticles, the majority of current studies continue to use a single-method approach.Under some soil conditions (i.e. pH 7, 10 mM NaCl and 2 mM CaCl₂) and increasing particle concentration, Fe₂O₃NPs underwent extensive aggregation to form large aggregates (>1 μm). Coating the nanoparticles with dissolved organic matter (DOM) was investigated as an alternative “green” solution to overcoming the aggregation issue instead of using the more commonly proposed polyelectrolytes. At high concentrations, DOM effectively covered the surface of the Fe₂O₃NPs, thereby conferring negative surface charge on the particles across a wide range of pH values. This provided electrostatic stabilisation and considerably reduced the particle aggregation effect. DOM-coated Fe₂O₃NPs also proved to be more stable under high ionic strength conditions. The presence of CaCl₂, however, even at low concentrations, induced the aggregation of DOM-coated Fe₂O₃NPs, mainly via charge neutralisation and bridging. This has significant implications in regards to the reactivity and fate of these materials in the environment.     

From urban renewal to local development. New conceptions and governance practices in the Italian peripheries

This article explores the relationships between changes in the conception of urban peripheries and changes in urban renewal policies, mainly focusing on policy debates and theoretical discourses developed within Italy. The aim is to test the usefulness of a non‐conventional approach to urban peripheries, both from a theoretical and practical point of view. According to this approach, urban peripheries can be thought of as plural and complex places, which are considered to be a fundamental part of the city and as the builders of urban identity. The article initially explores the changes in describing and interpreting urban peripheries, showing how they must be related to actual changes in urban settlement dynamics, as well as to changes in the theoretical frameworks used to understand the phenomenon of the Italian ‘urban periphery’. The article then shows how changes in interpretation have redefined the objectives and methods of policy interventions in the Italian context. Finally, certain critical issues will be discussed, in particular the origins of urban renewal policies and their recent evolution; the redefinition of the local authority role, and the relationships between institutional and social projects and activities. In this view, institutional projects are considered to be the formal projects carried out by public actors, for example municipalities, in order to manage the change in urban peripheries while social projects are understood as the informal practices of inhabitants of peripheries that change their living neighbourhoods.     

Aromatic triblock polymers from natural sources as protective coatings for stone surfaces

Aromatic triblock polymers were synthesized, characterized, and tested as protective coatings for stone surfaces. Syntheses were carried out by a ring opening polymerization process from specifically synthesized monomers ((3S)‐6‐methyl‐3‐phenyl‐1,4‐dioxan‐2,5‐dione or 1,4‐benzodioxepin‐3‐methyl‐2,5‐dione) and a perfluoropolyether diol (Fluorolink D10‐H), as chain initiator. Polymers were characterized through spectroscopic and analytical techniques while their stability under photo‐oxidative conditions was tested using a Solar Box. An excellent stability to environmental conditions was noticed with very low degradation during accelerated aging tests up to 1000 h, as detected by FTIR, molecular weight, DSC and weight loss. Furthermore, these polymers formed an excellent protective coating on the stone surface as shown by capillary water absorption test. Finally, as expected, very stable coatings were obtained as shown by aging tests. The stone surface showed negligible changes of color and a good hydrorepellency confirming a good durability of treatments. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43377.     

Additive Manufacturing of Ceramics Enabled by Flash Pyrolysis of Polymer Precursors with Nanoscale Layers

We show that a polymer‐based route to ceramics can be implemented into additive manufacturing by reducing the time for pyrolysis to about a second, which we call flash pyrolysis. Repetitive deposition of nanometer scale coatings of the ceramic, in this way, is employed to create defect‐free infiltrations of carbon fiber composites. The mechanical strength of the fibers is retained in the composite. Excellent wetting properties of the polymer precursor permits three‐dimensional, conformal coating through the three stages of infiltration: nanoscale coating of the single fibers, filling of interstitial spaces between the fibers, and a buildup of the coating over the entire composite. The flash pyrolysis method will enable a new genre of polymer‐derived ceramics made into net shape by this unusual method of additive manufacturing.     

Identification and Structure–Activity Relationship Studies of Small‐Molecule Inhibitors of the Methyllysine Reader Protein Spindlin1

The methyllysine reader protein Spindlin1 has been implicated in the tumorigenesis of several types of cancer and may be an attractive novel therapeutic target. Small‐molecule inhibitors of Spindlin1 should be valuable as chemical probes as well as potential new therapeutics. We applied an iterative virtual screening campaign, encompassing structure‐ and ligand‐based approaches, to identify potential Spindlin1 inhibitors from databases of commercially available compounds. Our in silico studies coupled with in vitro testing were successful in identifying novel Spindlin1 inhibitors. Several 4‐aminoquinazoline and quinazolinethione derivatives were among the active hit compounds, which indicated that these scaffolds represent promising lead structures for the development of Spindlin1 inhibitors. Subsequent lead optimization studies were hence carried out, and numerous derivatives of both lead scaffolds were synthesized. This resulted in the discovery of novel inhibitors of Spindlin1 and helped explore the structure–activity relationships of these inhibitor series.