Nanocelluloses with fiber diameter of ∼ 5 nm were extracted facilely from seasonal defoliation of ginkgo leaves by combined TEMPO-mediated oxidation/mechanical treatment and were used as adsorbents to remove charged contaminants from water. The chemical composition of nanocellulose was determined by solid-state 13C NMR and elemental analysis, whereas the morphology was characterized by TEM and POM techniques. The adsorption capacity of ginkgo nanocellulose against cationic dye molecules and heavy metal ions (e.g., cupric ions) were investigated in a static adsorption study. The results verified that nanocelluloses extracted from biomass waste, such as ginkgo leaves, could be used as efficient adsorption media for remediation of contaminated water.

We define Regenerative Engineering as a Convergence of Advanced Materials Science, Stem Cell Science, Physics, Developmental Biology, and Clinical Translation. We believe that an “un-siloed’ technology approach will be important in the future to realize grand challenges such as limb and organ regeneration. We also believe that biomaterials will play a key role in achieving overall translational goals. Through convergence of a number of technologies, with advanced materials science playing an important role, we believe the prospect of engaging future grand challenges is possible. Regenerative Engineering as a field is particularly suited for solving clinical problems that are relevant today. The paradigms utilized can be applied to the regeneration of tissue in the shoulder where tendon and muscle currently have low levels of regenerative capability, and the consequences, especially in alternative surgical solutions for massive tendon and muscle loss at the shoulder have demonstrated significant morbidity. Polymer, polymer-cell, and polymer biological factor, and polymer-physical systems can be utilized to propose a range of solutions to shoulder tissue regeneration. The approaches, possibilities, limitations and future strategies, allow for a variety of clinical solutions in musculoskeletal disease treatment.

In this contribution we report on the synthesis of n-type Bismuth vanadate (BiVO4) nanorods prepared via the use of aqueous extracts of Callistemon viminalis. X-ray diffraction analysis confirmed the formation of highly crystalline monoclinic BiVO4 nanorods post annealing of the Bismuth vanadate precursor powder at 500 °C. Scanning Electron Microscopy and High Resolution Transmission Electron Microscopy showed that BiVO4 nanorods have a high aspect ratio. Using UV-Vis absorption measurements the optical band gap of the nanorods is estimated to be 2.4 eV which makes the bio-synthesized BiVO4 powder a good candidate for sunlight driven photocatalysis.

Nanomaterials have broad application potential in biomedical and environmental science. Engineered nanomaterials are required to explore such potential. Among them carbon-based fluorescent nanoparticles offer promising alternative of conventionally used semiconductor nanocrystals, as they do not have heavy metals and associated toxicity issues. We are developing synthetic methods for high quality fluorescent carbon nanoparticle, suitable for biological staining and diagnostics. Here we focus on synthesis of fluorescent carbon nanoparticle from biomolecules, exploiting the conventionally used nucleation-growth conditions for synthesis of high quality nanocrystals such as quantum dot and metal oxides. We have shown that high quality fluorescent carbon nanoparticle can be synthesized from folic acid, riboflavin and lactose and they can be used as non-toxic bio-imaging probe.

This research shows the development of alternative Cu-based materials for applications where enhanced thermal properties are desired. Cu/AlN composites were fabricated from mixtures of pure Cu and copper plated AlN-Cu composite powders. The ceramic phase was added in amounts of 10, 20 and 30 vol.% and the mixtures sintered by pulsed electric current sintering process (PECS). The results showed that the AlN particles are homogeneously distributed in the copper matrix and that the true contacts between hard particles are reduced because of the deposited copper on their surfaces, improving the connectivity of the matrix phase and bonding at the metal-ceramic interface. The relative density of the Cu/AlN composites was major than 97% in all cases. Thermal conductivity of the composites was high and decreased with the ceramic content from 359 to 194 W/mK, for 10 and 30% AlN, respectively. The coefficient of thermal expansion followed a lineal behavior with temperature and is also reduced with the ceramic content.

It is important to achieve materials with large coefficient of thermal expansion in science and engineering applications. In this paper, we propose an experimentally-validated metamaterial approach to amplify the thermal expansion of materials based on the guiding principles of flexible hinges and displacement amplification mechanism. The thermal expansion property of the designed metamaterial is demonstrated by simulation and experiment with a temperature increase of 245 K for the two-dimensional sample. Both experimental and simulation results display amplified thermal expansion property of the metamaterial. The effective coefficient of thermal expansion of the metamaterials is demonstrated to be dependent on the size parameters of the structure, which means by appropriately tailoring these parameters, the thermal expansion of materials could be amplified with different amplification factor. This work provides an important method to control the thermal expansion coefficient of materials and could be applied in various industry domain.

High quality active layers for hybrid organic-inorganic perovskite solar cells are essential for achieving maximum device performance. However, perovskite active layers in solar cells are frequently prepared with unoptimized processes that lead to layers of inferior quality. This is often the case when research focuses on other aspects of the solar cell device, such as device design and architecture, carrier transport layers, electrodes, interlayers, etc. In this study, a single-step spin-coating method was used to prepare semi-crystalline PbI2(DMSO) complex films via evaporation-induced self-assembly. These optimized intermediate films were then used to form homogeneous methylammonium lead iodide (MAPbI3) perovskite films of optimum thickness (ca. 400 nm) with uniform surface coverage, good crystallinity, high purity, and grain sizes up to one micron, by employing a sequential deposition process involving intramolecular exchange between the PbI2(DMSO) complex film and a methylammonium iodide (MAI) layer deposited on top of it. We found that for certain ranges of MAI concentration, the formation of optimal-quality perovskite active layers was independent of MAI concentration, so long as MAI deposition occurred at specific corresponding spin speeds. Planar p-i-n perovskite solar cells comprising the optimized active layers were fabricated, and they exhibited negligible hysteresis and a maximum power conversion efficiency (PCE) of 16.72%, without any additional compositional and interfacial engineering. The latter can be used in the future to further enhance the PCE. These findings demonstrate the importance of an optimized perovskite active layer for reproducibly fabricating high-efficiency planar p-i-n photovoltaic devices. Additionally, the simplicity of the PbI2(DMSO) complex film preparation and the versatility of the MAI deposition with this fabrication method further enhances the potential of this material for large-scale processing.

The properties of a mixed metallic and semiconducting carbon nanotube (CNT) sample dispersed in nonconjugated poly(methyl methacrylate) (PMMA) and conjugated poly(bisdodecylquaterthiophene) (PQT12) were compared, with and without p-doping by NOBF4. The CNTs were distributed much more evenly, and percolated at much lower concentrations (ca. 2%), in the PMMA as compared to PQT12, as judged by optical microscopy and electronic conductivity measurements. Seebeck coefficients (S) obtained on the PMMA samples indicated dominance by the metallic fraction, with values <10 µV/K. Composites made with PQT12 alone showed slightly higher values of S, but with the addition of 3 wt % dopant, S increased markedly to about 100 µV/K at 5-10% CNT fractions, while conductivity was unexpectedly low. As the CNT fraction in the doped sample was increased to 25-30%, conductivity approached that of the comparable concentration of CNTs in PMMA, while S, ca. 15 µV/K, was still higher than that measured in PMMA. The observations inform interpretations of CNT-polymer composite thermoelectric data, pointing out the roles of conjugated main chains and added dopants in modulating contributions of CNTs to thermoelectric composite performance.

This paper reports on what differentiates the field of soft (i.e. soft-bodied) robotics from the conventional hard (i.e. rigid-bodied) robotics. The main difference centres on seamlessly combining the actuation, sensing, motion transmission and conversion mechanism elements, electronics and power source into a continuum body that ideally holds the properties of morphological computation and programmable compliance (i.e. softness). Another difference is about the materials they are made of. While the hard robots are made of rigid materials such as metals and hard plastics with a bulk elastic modulus of as low as 1 GPa, the monolithic soft robots should be fabricated from soft and hard materials or from a strategic combination of them with a maximum elasticity modulus of 1 GPa. Soft smart materials with programmable mechanical, electrical and rheological properties, and conformable to additive manufacturing based on 3D printing are essential to realise soft robots. Selecting the actuation concept and its power source, which is the first and most important step in establishing a robot, determines the size, weight, performance of the soft robot, the type of sensors and their location, control algorithm, power requirement and its associated flexible and stretchable electronics. This paper outlines how crucial the soft materials are in realising the actuation concept, which can be inspired from animal and plant movements.

Magnesium (Mg)-based biomaterials have attracted increasing attention in biomedical applications, such as orthopaedic, cardiovascular, urological, and neural applications because of the biocompatibility, biodegradability, antibacterial properties, and excellent mechanical properties. However, rapid degradation of Mg is the major concern for many clinical applications. Alloying Mg with other elements and engineering proper surfaces are the two approaches to control the degradation of Mg-based biomaterials. Our lab has investigated several classes of Mg-based biodegradable alloys and various surface treatment methods for medical implant and device applications. This mini-review highlights key research progress on Mg-based biomaterials and suggests future directions for Mg-based biomaterials.

In this paper, we presented design specifications and operational test results of large-sized high temperature superconducting (HTS) magnets for Superconducting Induction Heater (SIH). HTS magnets were designed and fabricated with the metal insulation method. Critical currents of the HTS magnets were estimated by considering the angular dependency on the magnetic flux density of HTS tape. The characteristic resistance, the charging and discharging time were calculated and measured in the liquid nitrogen and the conduction cooling condition achieved with the 2nd stage GM cryo-cooler. The saturated temperature of the HTS magnet reached at 5.6 K. The performances of the large-sized HTS magnet including cooling and magnetic field characteristics were tested under the conduction cooling. These results were evaluated with those of finite element method analysis results. The characteristic analysis results of the large-sized HTS magnets will be applied for development of the commercial 300 kW SIH.

The widespread occurrence and availability of coal makes it the world’s prime source of energy for different end use applications. Coal is commonly used for electricity production through coal combustion. However, many researchers have indicated that coal combustion is a prime contributor to emission of greenhouse gases contributing to global warming. During combustion gaseous elements such as sulfur, hydrogen, carbon and nitrogen react with oxygen to produce their respective oxides. These oxides contribute to global warming, air and water pollution as well as acid deposition. Emission of these oxides and their effect on the environment has resulted in increased interest in clean coal technologies. Clean coal technologies, such as coal gasification technology, use multiple technologies to control the emissions so as to minimize environmental effects from coal utilization.

In this paper, the characteristics of Morupule coal from the south and east main sections are determined to establish its suitability for gasification. The characterization was conducted using thermal analysis (Thermogravimetric Analyzer) and an X-Ray Fluorescence (XRF). Numerical simulation was also carried out using Ansys software for species transport. The samples proved the coal to be from a high ash and sulfur content and medium volatiles bituminous parent rock, whilst species transport revealed a sufficient syngas yield per kilogram of coal for downstream processes.

Significant developments in micro-electrical-mechanical systems (MEMS)-based devices for use in transmission electron microscopy (TEM) sample holders have recently led to the commercialization of windowed gas cells that now enable the atomic-resolution visualization of phenomena occurring during gas-solid interactions at atmospheric pressure. In situ atmospheric TEM study provides unique information that is beneficial to correlating the structure-properties relationship of catalytic nanomaterials, particularly under realistic gaseous reaction conditions. In this paper, we illustrate the capability of this novel in situ device as applied to our study of two catalyst systems: (1) In situ kinetic growth of free standing Pt nanowires as active catalysts toward oxygen reduction reaction (ORR); (2) In situ observation of facet-dependent oxidation of another promising ORR catalyst, Pt3Co nanoparticles.

A new family of six ionenes containing aromatic amide linkages has been synthesized from ready available starting materials at scales up to ∼50 g. These ionene-polyamides are all constitutional isomers and vary only in the regiochemistry of the amide linkages (para, meta) and xylyl linkages (ortho, meta, para) which are present in the polymer backbone. This paper details the synthesis of these ionenes and associated characterizations. Ionene-polyamides exhibit relatively low melting points (∼150 oC) allowing them to be readily processed into films and other objects. These ionene-polyamide materials are being developed for further study as polymer membranes for the separations of gases such as CO2, N2, CH4 and H2.

The work shows the preparation and characterization of composite materials using a polymer as a matrix (ABS) and carbon black or a graphenic material (graphene or graphene foam). The materials were individually mixed with the polymer and the process parameters were established in an extruder with capacity for temperature control starting at laboratory conditions and up to 600 °C. The process parameters were adjusted to form filaments that were subsequently used in a 3D printer. The parameters of the printing process were adjusted to achieve the production of flat prototypes. These prototypes were characterized by Digital Optical Microscopy. The degree of homogeneity of the prototypes and the working ranges for the graphene material concentrations were determined. Even though the characterizations were done in flat samples, 3D printing allows obtaining a great diversity of structure that broadens the diversity of applications for such kind of composite materials.

Four-wave mixing (FWM) is used to measure the vibrational modes of nanoparticles in solution. The vibrations give information about the particle size, material properties and shape. This method has been used for in-situ monitoring of the growth of nanoparticles with high accuracy, as confirmed by electron microscopy analysis. We observe a threshold in the FWM signal which we believe is from a cavity forming around the nanoparticles that reduces viscous damping. We have observed this effect in molecular dynamics simulations as well.

This paper discusses a pulse electroplating method for preparing copper (Cu)-coated gas diffusion electrodes (GDEs) for the electrochemical conversion of carbon dioxide (CO2) to hydrocarbons such as ethylene. Ionomer coating and air-plasma surface pre-treatments were explored as means of hydrophilizing the carbon surface to enable adhesion of electrodeposited material. The pulsed-current electrodeposition method used successfully generated copper and copper oxide micro- and nano-particles on the prepared surfaces. Copper(I) species identified on the ionomer-treated GDEs are presumed to be highly active for the selective generation of ethylene as compared to other gaseous byproducts of CO2 reduction. Conversely, copper catalysts deposited onto plasma-treated GDEs were found to have poor activity for hydrocarbon production, likely due to substantial metallic character. Of note, plasma treatment of an ionomer-treated GDE after copper plating yielded further improvements in catalytic activity and durability towards ethylene production.

Single-phase monazite-type ceramics are discussed as waste forms for the safe disposal of surplus plutonium or separated minor actinides. To derive a fundamental understanding of the long-term stability of these materials under repository relevant conditions, the dissolution kinetics of synthetic lanthanum monazite (LaPO4) were studied in dynamic dissolution experiments in the temperature range from 50 to 90°C under acidic conditions. The surface area normalised dissolution rates increased with temperature from 3.2·10-5 g m-2 d-1 at 50°C to 1.8·10-4 g m-2 d-1 at 90°C. The apparent activation energy Ea of the dissolution process was determined to be about 44 kJ mol-1, indicating a predominantly surface reaction controlled dissolution process in this temperature range. From thermodynamic considerations it can be inferred that the dissolution of the LaPO4 ceramics is governed by the dissolution of a thin layer of La-rhabdophane (LaPO4 · 0.667H2O) forming at the monazite surface in low temperature aqueous environments.

Efficient catalysts for the oxygen evolution reaction (OER) are widely applied in fuel cells and rechargeable lithium air batteries. It is desirable but challenging to achieve comparable activity to that of the noble-metal catalyst with non-precious metal catalyst. Highly active Co3O4 thin film electrodes have been successfully synthesized by a rapid one-step flame combustion synthesis method called Reactive Spray Deposition Technology. X-ray diffraction confirms the absence of any impurity phase with this synthesis process. The detailed morphology of the Co3O4 thin film is investigated with scanning electron microscopy and transmission electron microscopy. Cyclic voltammetry is used to investigate the redox activity of Co3+ to Co4+ which is crucial for the OER performance. The as-prepared Co3O4 catalyst demonstrates promising activity for OER, with an overpotential of 399 mV (at 10 mA cm-2) for OER.

The atmospheric pressure plasma sources with a coaxial geometry were used for generation of the radio frequency, microwave and pulsed dc plasmas inside water and aqueous solutions. Pulsed dc plasma generated in ethanol-water mixtures leads to production of the hydrogen-rich synthesis gas with hydrogen content up to 65 %. The effect of various plasma generation regimes on the performance of plasma, on the hydrogen production efficiency and on the hydrogen-rich synthesis gas production was examined. A role of the composition of the ethanol-water mixture was investigated.