Scalable Methodology Research Articles

Cesium salts as superior catalysts for solvent-free modifications of biosourced pterolactam

γ-Lactam derivatives are widespread biologically active compounds, covering a large range of activities. Following our interest in both medicinal and green chemistries, we developed an original, cesium salts-mediated, scalable and solvent-free methodology to transform biosourced pyroglutamic acid and its derivatives to their N,N′-aminals, N,O,N,S-acetals and C5-substituted γ-lactams in good to excellent yields. This protocol is applicable to a large range of substrates, conducting to C5-substituted γ-lactam derivatives as potential new biologically active compounds.

Improving electrocoagulation floatation for harvesting microalgae

Electro-coagulation floatation (ECF) is a foam-floatation dewatering method that has been shown to be a highly effective, rapid, and scalable separation methodology. In this manuscript, an in-depth analysis of the gas and flocculant levels observed during the process is provided, with microbubbles observed in the 5–80 μm size range at a concentration of 102–103 bubbles mL−1. Electrolysis of microalgae culture was then observed, demonstrating both effective separation using aluminium electrodes (nine microalgal species tested, 1–40 μm size range, motile and non-motile, marine and freshwater), and sterilisation of culture through bleaching with inert titanium electrodes. Atomic force microscopy was used to visualise floc formation in the presence and absence of algae, showing nanoscale structures on the magnitude of 40–400 nm and entrapped microalgal cells. Improvements to aid industrial biotechnology processing were investigated: protein-doping was found to improve foam stability without inducing cell lysis, and an oxalate buffer wash regime was found to dissolve the flocculant whilst producing no observable difference in the final algal lipid or pigment profiles, leaving the cells viable at the end of the process. ECF separated microalgal culture had an algal biomass loading of 13% and as such was ideal for direct down-stream processing through hydrothermal liquefaction. High bio-crude yields were achieved, though this was reduced slightly on addition of the Al(OH)3 after ECF, with carbon being distributed away to the aqueous and solid residue phases. The amenability and compatibility of ECF to integration with, or replacement of, existing centrifugation and settling processes suggests this process may be of significant interest to the biotechnology industry.

An Ultralow Phase Noise Eight-Core Fundamental 62-to-67-GHz VCO in 65-nm CMOS

An eight-core fundamental VCO with ultralow phase noise (PN) performance is presented. Eight VCOs are in-phase coupled for low PN, and a 9-dB PN improvement is achieved. A scalable layout methodology is presented to solve the layout difficulties in multicore VCOs. Two VCO cores are connected together directly to form a VCO cell. By simply connecting $N$ /2 VCO cells, the PN of the entire multicore VCO will achieve a 10 logN dB PN improvement compared with the single VCO core. The proposed eight-core VCO is fabricated in 65-nm CMOS and occupies 0.15 mm2. The measured PN is −105.5 dBc/Hz at 1-MHz offset, with the tuning range from 62.2 to 67.3 GHz (7.9%). The VCO consumes 61.2-mW power with the figure-of-merit of −183.5 dBc/Hz at 1-MHz offset.

Generalists are the most urban‐tolerant of birds: a phylogenetically controlled analysis of ecological and life history traits using a novel continuous measure of bird responses to urbanization

Identifying which ecological and life history traits influence a species’ tolerance to urbanization is critical to understanding the trajectory of biodiversity in an increasingly urbanizing world. There is evidence for a wide array of contrasting patterns for single trait associations with urbanization. In a continental‐scale analysis, incorporating 477 species and >5 000 000 bird observations, we developed a novel and scalable methodology that evaluated the ecological and life history traits which most influence a species’ adaptability to persist in urban environments. Specifically, we assigned species‐specific scores based on continuous measures of response to urbanization, using VIIRS night‐time light values (i.e. radiance) as a proxy for urbanization. We identified generalized, phylogenetically controlled patterns: bird species which are generalists (i.e. large niche breadth), with large clutch size, and large residual brain size are among the most urban‐tolerant bird species. Conversely, specialized feeding strategies (i.e. insectivores and granivores) were negatively associated with urbanization. Enhancement and persistence of avian biodiversity in urban environments probably relies on protecting, maintaining and restoring diverse habitats serving a range of life history strategies.

Macromolecules with programmable shape, size, and chemistry

Shape, size, and composition are the most fundamental design features, enabling highly complex functionalities. Despite recent advances, the independent control of shape, size, and chemistry of macromolecules remains a synthetic challenge. We report a scalable methodology to produce large, well-defined macromolecules with programmable shape, size, and chemistry that combines reactor engineering principles and controlled polymerizations. Specifically, bottlebrush polymers with conical, ellipsoidal, and concave architectures are synthesized using two orthogonal polymerizations. The chemical versatility is highlighted by the synthesis of a compositional asymmetric cone. The strong agreement between predictions and experiments validates the precision that this methodology offers.

Monitoring aquatic plants: An evaluation of hydroacoustic, on-site digitising and airborne remote sensing techniques

Aquatic macrophytes are often monitored to detect change in ecosystem function and state, as well as assessing the effectiveness of invasive aquatic plant management. This study compares seven methodologies to monitor the distribution and abundances of aquatic macrophytes. Four line transect methodologies and three spatial mapping techniques were employed in parallel over a broad turbidity gradient in two lentic habitats of south-eastern Australia. The methodologies examined included hydroacoustic surveys, on-site digitising, and digitisation of airborne remote sensing imagery. Variation in estimates of macrophyte coverage were observed between methodologies. Consistency in the collection and interpretation of data was greatest for the line transect methodologies and the digitisation of satellite imagery. Duel-frequency identification sonar proved to be an effective novel hydroacoustic technique to monitor macrophyte abundances over broad spatial scales. Single beam sonar transects was also an objective, repeatable and scalable methodology. Videography and on-site handheld PDA mapping were of limited utility due to restrictions imposed by turbidity. The utility of sidescan sonar could be improved when used in conjunction with on-site handheld PDA mapping. This study outlines important considerations when selecting a methodology to monitor macrophyte distribution and abundance. Results indicate that no one specific method can be employed across all macrophyte monitoring studies. The method or combination of methods employed during macrophyte monitoring studies is dependent upon the study objectives, budget and environmental conditions of the study site.

Experimental validation of a ducted wind turbine design strategy

Abstract. A synergistic design strategy for ducted horizontal axis wind turbines (DWTs), utilizing the numerical solution of a ducted actuator disk system as the input condition for a modified blade element momentum method, is presented. Computational results of the ducted disk have shown that the incoming flow field for a DWT differs substantially from that of a conventional open rotor. The rotor plane velocity is increased in the ducted flow field, and, more importantly, the axial velocity component varies radially. An experimental full-scale 2.5 m rotor and duct were designed, using this numerical strategy, and tested at the University of Waterloo's wind turbine test facility. Experimental results indicated a very good correlation of the data with the numerical predictions, namely a doubling of the power output at a given velocity, suggesting that the numerical strategy can provide a means for a scalable design methodology.

Spatially Self-Confined Formation of Ultrafine NiCoO2 Nanoparticles@Ultralong Amorphous N-Doped Carbon Nanofibers as an Anode towards Efficient Capacitive Li+ Storage.

The exploration of anode materials with a high degree of electrochemical utilization for Li-ion batteries (LIBs) still remains a huge challenge despite pioneering breakthroughs. Rational engineering of electrode structures/components by facile strategies would offer infinite possibilities for the development of LIBs. In this study, one-dimensional ultralong nanohybrids of ultrafine NiCoO2 nanoparticles dispersed in situ in and/or on the surface of amorphous N-doped carbon nanofibers (NCO@ANCNFs) were fabricated by a bottom-up electrospinning protocol. By virtue of synergistic structural/component features, the obtained ultralong NCO@ANCNFs with low NCO loading (≈33.6 wt %) show highly efficient Li+ storage performance with high reversible capacity, high rate capability, and long cycle life. The unusual reversible crystalline transformation during cycling was analyzed. Quantitative analysis revealed that the pseudocapacitive contribution mainly accounts for the superior lithium storage of the NCO@ANCNFs. Besides, the ability of the hybrid anode to deliver competitive Li-storage properties even without conductive carbon greatly enhances its commercial applicability. An NCO@ANCNFs//LiNi0.8 Co0.15 Al0.05 O2 full battery was assembled and exhibited striking electrochemical properties. This contribution offers a scalable methodology to fabricate highly efficient hybrid anodes for advanced next-generation LIBs.

Mechanically Guided Assembly of Monolithic Three-Dimensional Structures from Elastomer Composites.

Mechanically guided assembly is considered a facile and scalable methodology for fabrication of three-dimensional (3D) structures. However, most of the previous methods require multistep processes for bonding bi- or multilayers and only result in non-freestanding 3D structures because of usage of a supporting elastomer substrate. Herein, we report a functional elastomer composite that can be transformed to a freestanding and monolithic 3D structure driven by the mechanically guided assembly. Photolithography can be used to selectively tune the mechanical properties of UV-exposed regions which exhibit enhanced ductility compared with the nonexposed regions. Thus, a gradient of the residual strain in the thickness direction makes the films assemble into 3D structures. These 3D structures are also predicted by our computational models using finite element simulations, which yields a reasonable agreement with the experiments. The systematically designed 2D structures with varied patterns can be transformed to various 3D structures with the control of the residual strain gradient, via key processing parameters including pre-strain, film thickness, and UV exposure time. By integrating different active electronic components on the fabricated 3D structures, potential applications of this 3D platform in electronics were demonstrated. This study offers a unique capability in constructing monolithic and freestanding 3D assembly, paving new routes to many applications such as wearable electronics, smart textiles, soft robotics, and structural health monitoring.

Decorated fibrous silica epoxy coating exhibiting anti-corrosion properties

In this paper we report a simple approach of preparation of fibrous superhydrophobic silica employing a low cost and scalable methodology. The prepared superhydrophobic fibrous silica was characterized using thermal gravimetric analysis, transmission electron microscopy, Fourier transform infrared spectrophotometry (FTIR) and 13C solid-state NMR spectroscopy. The findings revealed that the hydrophobic alkyl chains were introduced into silica particles via modification and the fibrous silica particles were modified from a hydrophilic to hydrophobic nature. TEM analysis revealed that the unique morphology of the fibrous silica remained intact after its modification with alkoxysilane reagents. The particles were spatially stuck on the surface of the epoxy resin coating with the purpose to create a rough surface with random micro/nano structures. The prepared superhydrophobic surface exhibited robust water-repellent surface, excellent durability and corrosion resistance. It not only introduces a cost-effective process for superhydrophobic modification of epoxy coating, but also provides a promising strategy to protect metals by simultaneously combining the protective functions of both superhydrophobic surface and organic protective coating, which could be employed for large-scale industrial fabrication of superhydrophobic epoxy coating onto steel materials.

DESIGNING FOR AUTISM: AN ASPECTSS™ POST-OCCUPANCY EVALUATION OF LEARNING ENVIRONMENTS

The objective of this paper is to demonstrate the application of the Autism ASPECTSS™ Design Index in the Post-Occupancy Evaluation of existing learning environments for children along the autism spectrum. First published in 2014 this index outlines 7 design criteria that have been hypothesized to support environments conducive of learning for children with autism spectrum disorder (ASD). Using the index as a framework, this paper outlines a case study of a Post-Occupancy Evaluation (POE) of an existing pre-K-8th grade public charter purpose-built school for children on the autism spectrum. The tools used for the evaluation were: the ASPECTSS scoring of the school through a survey of teachers and administrators; on-site behavioral in-class observation; and focus groups of parents, teachers, staff and administrators. The results informed a design retro-fit proposal that strived to assess any ASPECTSS compliance issues and implement the index across the learning spaces, therapy spaces, support services and outdoor learning environments of the school. This paper will outline the application of the index and the resultant design from this process. The results will strive to present a scalable and replicable methodology and prototype for improving existing built environments for learners with ASD.

Scalable Compact Modeling of III–V DHBTs: Prospective Figures of Merit Toward Terahertz Operation

We investigate the bias, temperature, and frequency dependence of two III–V double heterojunction bipolar transistors technologies based on InGaAs/InP and GaAsSb/InP processes, using a HiCuM/L2 compact model-based multigeometry scalable parameter extraction methodology. Very good agreement between the model simulations and experimental data is demonstrated. Transistor currents and junction capacitances show very good scaling, thereby allowing the separation of intrinsic and peripheral effects. Prediction of future III–V HBT technologies figures-of-merit is performed by using the generated scalable model card.

Printed Nanocomposite Energy Harvesters with Controlled Alignment of Barium Titanate Nanowires.

Piezoelectric nanocomposites are commonly used in the development of self-powered miniaturized electronic devices and sensors. Although the incorporation of one-dimensional (1D) piezoelectric nanomaterials (i.e., nanowires, nanorods, and nanofibers) in a polymer matrix has led to the development of devices with promising energy harvesting and sensing performance, they have not yet reached their ultimate performance due to the challenges in fabrication. Here, a direct-write additive manufacturing technique is utilized to facilitate the fabrication of spatially tailored piezoelectric nanocomposites. High aspect ratio barium titanate (BaTiO3) nanowires (NWs) are dispersed in a polylactic acid (PLA) solution to produce a printable piezoelectric solution. The BaTiO3 NWs are arranged in PLA along three different axes of alignment via shear-induced alignment during a controlled printing process. The result of electromechanical characterizations shows that the nanowire alignment significantly affects the energy harvesting performance of the nanocomposites. The optimal power output can be enhanced by as much as eight times for printed nanocomposites with a tailored architecture of the embedded nanostructures. This power generation capacity is 273% higher compared to conventional cast nanocomposites with randomly oriented NWs. The findings of this study suggest that 3D printing of nanowire-based nanocomposites is a feasible, scalable, and rapid methodology to produce high-performance piezoelectric transducers with tailored micro- and nanostructures. This study offers the first demonstration of nanocomposite energy harvesters with spatially controlled filler orientation realized directly from a digital design.

Scalable authentic assessment of collaborative work assignments in wikis

Wikis are appropriate tools for deploying authentic assessment experiences for learning and work scenarios in which a group of users are asked to develop a shared task. However, when the number of wiki users increases, the number of contributions can grow at a pace whereby accurately assessing them becomes a complex and non-scalable task. While different quantitative approaches have been shown to be scalable, they are usually coarse-grained and provide limited feedback about the assessment. This work proposes a scalable assessment methodology for wiki-based tasks, based on qualitative self- and peer assessment of wiki contributions. The methodology is implemented using a software tool and is applied as part of an undergraduate course, complementing a quantitative assessment approach. Positive evidence on the scalability of the method and how it implements a more fine-grained qualitative assessment than the regular quantitative approach is found, providing indicators for assessing both individual and group generic skills.

Au-TiO2-Loaded Cubic g-C3N4 Nanohybrids for Photocatalytic and Volatile Organic Amine Sensing Applications.

A green and efficient approach for efficient nanohybrid photocatalysts in extending the light response to the visible spectrum is a hot research topic in sustainable energy technologies. In this work, novel Au-TiO2@m-CN nanocomposite was synthesized using hard template of cubic ordered mesoporous KIT-6 via the nanocasting process. The as-prepared Au-TiO2@m-CN nanohybrids exhibit enhanced photocatalytic activities with improved stability and reusability using methyl orange dye. The enhanced photocatalytic performance is a result of the conjugated effect of catalytic active Au and TiO2 nanoparticles supported on highly efficient visible light sensitizer, graphitic carbon nitride (m-CN or g-C3N4), and ordered mesoporous morphology. Besides, the sensing performance of Au-TiO2@m-CN nanohybrids was also tested for the detection of amine gases, wherein a significant response was reported for triethylamine at low operating temperatures. This study reveals a simple and scalable methodology to design and develop next generation of layered mesoporous materials for multifunctional applications.

Scalable Manufacturing of Nanogaps.

The ability to manufacture a nanogap in between two electrodes has proven a powerful catalyst for scientific discoveries in nanoscience and molecular electronics. A wide range of bottom-up and top-down methodologies are now available to fabricate nanogaps that are less than 10 nm wide. However, most available techniques involve time-consuming serial processes that are not compatible with large-scale manufacturing of nanogap devices. The scalable manufacturing of sub-10 nm gaps remains a great technological challenge that currently hinders both experimental nanoscience and the prospects for commercial exploitation of nanogap devices. Here, available nanogap fabrication methodologies are reviewed and a detailed comparison of their merits is provided, with special focus on large-scale and reproducible manufacturing of nanogaps. The most promising approaches that could achieve a breakthrough in research and commercial applications are identified. Emerging scalable nanogap manufacturing methodologies will ultimately enable applications with high scientific and societal impact, including high-speed whole genome sequencing, electromechanical computing, and molecular electronics using nanogap electrodes.

Scalable Synthesis of a Ruthenium-Based Electrocatalyst as a Promising Alternative to Pt for Hydrogen Evolution Reaction.

Designing highly active, stable, and cost-efficient electrocatalysts as alternatives to replace Pt is extremely desirable for hydrogen evolution reaction (HER). Despite much progress that has been made based on complete nonprecious metals (NPMs), very few NPM catalysts have shown comparable performance to Pt-based catalysts. Herein, a cost-efficient, environmentally friendly, and scalable method to synthesize a novel ruthenium(Ru)-doped transition-metal carbide (Mo2C) hybrid catalyst was proposed. The hybrid nanoparticles were uniformly distributed and strongly embedded in a biomass-derived highly porous N-doped carbon framework. In particular, Mo2C@Ru exhibited a Pt-like remarkable electrocatalytic performance for HER, and it only required an extremely low overpotential of 24.6 mV to reach the current density of 10 mA cm-2. Furthermore, our density functional theory calculations indicated that the nanocomposite exhibits improved metal-hydrogen binding and favorable hydrogen adsorption energy, which is comparable to that of Pt. The facile and scalable synthesis methodology, the relatively low cost, and the excellent electrochemical HER performance comparable to that of commercial Pt/C suggest that the Mo2C@Ru electrocatalyst is a promising alternative to Pt for large-scale hydrogen production.

A scalable solution strategy for high-order stabilized finite-element solvers using an implicit line preconditioner

This paper presents a robust, efficient, and strongly scalable solution methodology for simulation of complex turbulent flows on unstructured grids. The compressible Reynolds averaged Navier–Stokes (RANS) equations and the negative Spalart–Allmaras (SA) turbulence model are discretized, in coupled form, using a Streamline Upwind Petrov–Galerkin (SUPG) scheme. The time integration is fully implicit, and the discretized equations are advanced towards a steady-state solution using a pseudo-transient continuation (PTC). For solution of the linearized systems, a preconditioned Krylov solver is used. Seeking robustness, Krylov solvers are commonly preconditioned using incomplete factorization methods such as ILU(k). However, these methods are neither memory efficient, nor strongly scalable. To provide a better alternative, the implicit line solution method, which has been traditionally used in finite-volume methods, is revised and enhanced to solve stiffer linear systems. In the developed method, the lines are generated using a matrix-based approach, which connects the strongly-coupled unknowns. In addition, to improve the robustness of the line solver for high-CFL systems, a dual-CFL strategy, with a lower CFL number in the preconditioner matrix, is developed. Also, it is shown that for high-order continuous finite-element discretizations, the interconnections of the degrees of freedom on a line form a banded matrix which is wider than tridiagonal, but still can be factorized completely without generating any fill-ins. The developed line preconditioner is strongly scalable and, in contrast to the ILU factorization, its convergence behavior does not depend on the number of partitions. Two three-dimensional numerical examples are presented in which the performance of the line preconditioner is compared with that of the ILU(k) preconditioner. This comparison shows that, in addition to robustness improvements, the line preconditioner offers significant benefits in terms of memory efficiency.

Startups’ Roads to Failure

The role of a relatively small cadre of high-tech startup firms in driving innovation and economic growth has been well known and amply celebrated in recent history. At the same time, it is well recognized that, while the overall contribution of startups is crucial, the high-risk and high-reward strategy followed by these startups leads to significant failure rates and a low ratio of successful startups. So, it is curious to notice that literature tends to focus on successful startups and on quantitative studies looking for determinants of success while neglecting the numerous lessons that can be drawn by examining the stories of startups that failed. This paper aims to fill this gap and to contribute to the literature by providing a repeatable and scalable methodology that can be applied to databases of unstructured post-mortem documents deriving startup failure patterns. A further and related contribution is the analysis carried out with this methodology to a large database of 214 startup post-mortem reports. Descriptive statistics show how the lack of a structured Business Development strategy emerges as a key determinant of startup failure in the majority of cases.

Sulfanilic Acid Pending on a Graphene Scaffold: Novel, Efficient Synthesis and Much Enhanced Polymer Solar Cell Efficiency and Stability Using It as a Hole Extraction Layer.

In this contribution, we describe a novel, facile, and scalable methodology for high degree functionalization toward graphene by the reaction between bulk graphite fluoride and in situ generated amine anion. Using this, the rationally designed sulfanilic acid pending on a graphene scaffold (G-SO3H), a two-dimensional (2D) π-conjugated counterpart of poly(styrenesulfonate), is available. Combined reliable characterizations demonstrate that a very large quantity of sulfanilic blocks are linked to graphene through the foreseen substitution of carbon-fluorine units and an unexpected reductive defluorination simultaneously proceeds during the one-step reaction, endowing the resultant G-SO3H with splendid dispersity in various solvents and film-forming property via the former, and with recovered 2D π-conjugation via the latter. Besides, the work function of G-SO3H lies at -4.8 eV, well matched with the P3HT donor. Awarded with these fantastic merits, G-SO3H behaves capable in hole collection and transport, indicated by the enhanced device efficiency and stability of polymer solar cells (PSCs) based on intensively studied P3HT:PCBM blends as an active layer. In particular, comparison with conventional poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) and recently rising and shining graphene oxide, G-SO3H outperforms above 17 and 24%, respectively, in efficiency. More impressively, when these three unencapsulated devices are placed in a N2-filled glovebox at around 25 °C for 7 weeks, or subject to thermal treatment at 150 °C for 6 h also in N2 atmosphere, or even rudely exposed to indoor air, G-SO3H-based PSCs exhibit the best stability. These findings enable G-SO3H to be a strongly competitive alternative of the existing hole extraction materials for PSC real-life applications.