scholarly journals Milling as a route to porous graphitic carbons from biomass

2021 ◽  
Vol 379 (2209) ◽  
pp. 20200336
Author(s):  
R. D. Hunter ◽  
J. Davies ◽  
S. J. A. Hérou ◽  
A. Kulak ◽  
Z. Schnepp
Keyword(s):  
Lignocellulosic Biomass ◽  
Iron Catalyst ◽  
Adsorption Properties ◽  
Advanced Materials ◽  
Catalyst Precursor ◽  
Waste Biomass ◽  
Theme Issue ◽  
Simple Method ◽  
Fine Powders ◽  
Wide Range

This paper reports a simple way to produce porous graphitic carbons from a wide range of lignocellulosic biomass sources, including nut shells, softwood sawdust, seed husks and bamboo. Biomass precursors are milled and sieved to produce fine powders and are then converted to porous graphitic carbons by iron-catalysed graphitization. Graphitizing the raw (unmilled) biomass creates carbons that are diverse in their porosity and adsorption properties. This is due to the inability of the iron catalyst precursor to penetrate the structure of dense biomass material. Milling enables much more efficient impregnation of the biomass and produces carbons with homogeneous properties. Lignocellulosic biomass (particularly waste biomass) is an attractive precursor to technologically important porous graphitic carbons as it is abundant and renewable. This simple method for preparing the biomass enables a wide range of biomass sources to be used to produce carbons with homogeneous properties. This article is part of the theme issue ‘Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 2)’.

scholarly journals The spider cuticle: a remarkable material toolbox for functional diversity

2021 ◽  
Vol 379 (2206) ◽  
pp. 20200332 ◽  
Author(s):  
Yael Politi ◽  
Luca Bertinetti ◽  
Peter Fratzl ◽  
Friedrich G. Barth
Keyword(s):  
Design Space ◽  
Sensory Information ◽  
Advanced Materials ◽  
Single Type ◽  
Theme Issue ◽  
Light Manipulation ◽  
Wide Range ◽  
Compositional Changes ◽  
Engineered Systems ◽  
Internal Architecture

Engineered systems are typically based on a large variety of materials differing in composition and processing to provide the desired functionality. Nature, however, has evolved materials that are used for a wide range of functional challenges with minimal compositional changes. The exoskeletal cuticle of spiders, as well as of other arthropods such as insects and crustaceans, is based on a combination of chitin, protein, water and small amounts of organic cross-linkers or minerals. Spiders use it to obtain mechanical support structures and lever systems for locomotion, protection from adverse environmental influences, tools for piercing, cutting and interlocking, auxiliary structures for the transmission and filtering of sensory information, structural colours, transparent lenses for light manipulation and more. This paper illustrates the ‘design space’ of a single type of composite with varying internal architecture and its remarkable capability to serve a diversity of functions. This article is part of the theme issue ‘Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 1)’.

scholarly journals Introduction to redundancy rules: the continuous wavelet transform comes of age

2018 ◽  
Vol 376 (2126) ◽  
pp. 20170258 ◽  
Author(s):  
Paul S. Addison
Keyword(s):  
Wavelet Transform ◽  
Continuous Wavelet Transform ◽  
State Of The Art ◽  
Structural Characteristics ◽  
Continuous Wavelet ◽  
Theme Issue ◽  
Current State ◽  
Analysis Methods ◽  
Wide Range ◽  
New Form

Redundancy: it is a word heavy with connotations of lacking usefulness. I often hear that the rationale for not using the continuous wavelet transform (CWT)—even when it appears most appropriate for the problem at hand—is that it is ‘redundant’. Sometimes the conversation ends there, as if self-explanatory. However, in the context of the CWT, ‘redundant’ is not a pejorative term, it simply refers to a less compact form used to represent the information within the signal. The benefit of this new form—the CWT—is that it allows for intricate structural characteristics of the signal information to be made manifest within the transform space, where it can be more amenable to study: resolution over redundancy. Once the signal information is in CWT form, a range of powerful analysis methods can then be employed for its extraction, interpretation and/or manipulation. This theme issue is intended to provide the reader with an overview of the current state of the art of CWT analysis methods from across a wide range of numerate disciplines, including fluid dynamics, structural mechanics, geophysics, medicine, astronomy and finance. This article is part of the theme issue ‘Redundancy rules: the continuous wavelet transform comes of age’.

scholarly journals Automatic and Online Detection of Rotor Fault State

2018 ◽  
Vol 7 (1) ◽  
pp. 43 ◽  
Author(s):  
Ali Ouanas ◽  
Ammar Medoued ◽  
Salim Haddad ◽  
Mourad Mordjaoui ◽  
D. Sayad
Keyword(s):  
Induction Motor ◽  
Dimensional Space ◽  
Operating Conditions ◽  
Online Detection ◽  
K Nearest Neighbor ◽  
Simple Method ◽  
Important Place ◽  
Motor Test ◽  
Wide Range ◽  
Fault State

In this work, we propose a new and simple method to insure an online and automatic detection of faults that affect induction motor rotors. Induction motors now occupy an important place in the industrial environment and cover an extremely wide range of applications. They require a system installation that monitors the motor state to suit the operating conditions for a given application. The proposed method is based on the consideration of the spectrum of the single-phase stator current envelope as input of the detection algorithm. The characteristics related to the broken bar fault in the frequency domain extracted from the Hilbert Transform is used to estimate the fault severity for different load levels through classification tools. The frequency analysis of the envelope gives the frequency component and the associated amplitude which define the existence of the fault. The clustering of the indicator is chosen in a two-dimensional space by the fuzzy c mean clustering to find the center of each class. The distance criterion, the K-Nearest Neighbor (KNN) algorithm and the neural networks are used to determine the fault type. This method is validated on a 5.5-kW induction motor test bench.Article History: Received July 16th 2017; Received: October 5th 2017; Accepted: Januari 6th 2018; Available onlineHow to Cite This Article: Ouanas, A., Medoued, A., Haddad, S., Mordjaoui, M., and Sayad, D. (2017) Automatic and online Detection of Rotor Fault State. International Journal of Renewable Energy Development, 7(1), 43-52.http://dx.doi.org/10.14710/ijred.7.1.43-52

scholarly journals Development of a New Stoichiometric Equilibrium-Based Model for Wood Chips and Mixed Paper Wastes Gasification by ASPEN Plus

2019 ◽  
Author(s):  
Sahar Safarianbana ◽  
Runar Unnthorsson ◽  
Christiaan Richter
Keyword(s):  
Moisture Content ◽  
Aspen Plus ◽  
Wood Chips ◽  
Thermochemical Conversion ◽  
Waste Biomass ◽  
Operation Conditions ◽  
High Heating Value ◽  
Cold Gas Efficiency ◽  
Wide Range ◽  
Steady State Simulation

Abstract Wood and paper residues are usually processed as wastes, but they can also be used to produce electrical and thermal energy through processes of thermochemical conversion of gasification. This study proposes a new steady state simulation model for down draft waste biomass gasification developed using the commercial software Aspen Plus for optimization of the gasifier performance. The model was validated by comparison with experimental data obtained from six different operation conditions. This model is used for analysis of gasification performance of wood chips and mixed paper wastes. The operating parameters of temperature and moisture content (MC) have been varied over wide range and their effect on the high heating value (HHV) of syngas and cold gas efficiency (CGE) were investigated. The results show that increasing the temperature improves the gasifier performance and it increases the production of CO and H2 which leads to higher LHV and CGE. However, an increase in moisture content reduces gasifier performance and results in low CGE.

Synthesis of bio-based 2-thiothiophenes

2021 ◽  
Vol 379 (2209) ◽  
pp. 20200350
Author(s):  
Yichen Qiu ◽  
Yunchao Feng ◽  
Ashley C. Lindsay ◽  
Xianhai Zeng ◽  
Jonathan Sperry
Keyword(s):  
Small Molecule ◽  
Chemical Industry ◽  
Emerging Technologies ◽  
Advanced Materials ◽  
Organosulfur Compounds ◽  
Theme Issue ◽  
Widespread Application ◽  
Fossil Carbon ◽  
Functionally Diverse

While the synthesis of bio-based compounds containing carbon, oxygen and (to a lesser extent) nitrogen is well studied, the production of organosulfur compounds from biomass has received virtually no attention, despite their widespread application throughout the chemical industry. Herein, we demonstrate that a range of bio-based 2-thiothiophenes are available from the biopolymer cellulose, proving that functionally diverse small-molecule organosulfurs can be prepared independent of fossil carbon. This article is part of the theme issue ‘Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 2)’.

Simplified approach to confidence limited in radioimmunassay.

1980 ◽  
Vol 26 (6) ◽  
pp. 763-765 ◽  
Author(s):  
R C Baxter
Keyword(s):  
Quality Control ◽  
Mean Value ◽  
Confidence Limits ◽  
Simple Method ◽  
Response Variable ◽  
Simplified Approach ◽  
Quadratic Curve ◽  
Wide Range ◽  
Advanced Computing ◽  
Routine Quality Control

Abstract A simple method of calculating confidence limits for radioimmunoassay data is presented. The method involves the use of the within-assay variation in dose estimate of three routine quality-control specimens, measured in repeated assays, to estimate the confidence limits for results on unknown samples. Results for control specimens are combined by calculating the unique quadratic curve fitting a graph of within-assay standard deviation vs mean value for each control. This method requires no special data accumulation or advanced computing equipment. For cortisol, lutropin, and thyroxine radioimmunoassays, confidence limits calculated in this way have been compared with those calculated from the variance of the response variable “B/B0” in repeated standard curves. Both methods agree well with actual limits observed when plasma pools containing a wide range of hormone concentrations are assayed repeatedly.

scholarly journals Rheology of magnetic colloids containing clusters of particle platelets and polymer nanofibres

2020 ◽  
Vol 378 (2171) ◽  
pp. 20190255 ◽  
Author(s):  
Mariem Mekni Abrougui ◽  
Ezzeddine Srasra ◽  
Modesto T. Lopez-Lopez ◽  
Juan D. G. Duran
Keyword(s):  
Magnetic Fields ◽  
Magnetic Particles ◽  
Polymer Network ◽  
Soft Materials ◽  
Design Parameters ◽  
Heterogeneous Structure ◽  
High Porosity ◽  
Theme Issue ◽  
Wide Range ◽  
Magnetorheological Effect

Magnetic hydrogels (ferrogels) are soft materials with a wide range of applications, especially in biomedicine because (i) they can be provided with the required biocompatibility; (ii) their heterogeneous structure allows their use as scaffolds for tissue engineering; (iii) their mechanical properties can be modified by changing different design parameters or by the action of magnetic fields. These characteristics confer them unique properties for acting as patterns that mimic the architecture of biological systems. In addition, and (iv) given their high porosity and aqueous content, ferrogels can be loaded with drugs and guided towards specific targets for local (non-systemic) pharmaceutical treatments. The ferrogels prepared in this work contain magnetic particles obtained by precipitation of magnetite nanoparticles onto the porous surface of bentonite platelets. Then, the particles were functionalized by adsorption of alginate molecules and dispersed in an aqueous solution of sodium alginate. Finally, the gelation was promoted by cross-linking the alginate molecules with Ca 2+ ions. The viscoelastic properties of the ferrogels were measured in the absence/presence of external magnetic fields, showing that these ferrogels exhibited a strong enough magnetorheological effect. This behaviour is explained considering the field-induced strengthening of the heterogeneous (particle–polymer) network generated inside the ferrogel. This article is part of the theme issue ‘Patterns in soft and biological matters'.

scholarly journals A simple enzymatic assay for the quantification of C1-specific cellulose oxidation by lytic polysaccharide monooxygenases

2019 ◽  
Vol 42 (1) ◽  
pp. 93-102 ◽  
Author(s):  
M. B. Keller ◽  
C. Felby ◽  
C. A. Labate ◽  
V. O. A. Pellegrini ◽  
P. Higasi ◽  
...  
Keyword(s):  
Lignocellulosic Biomass ◽  
Oxidation Product ◽  
Gluconic Acid ◽  
Enzymatic Assay ◽  
Cellulose Oxidation ◽  
Metal Chelator ◽  
Pure Cellulose ◽  
Lytic Polysaccharide Monooxygenases ◽  
Wide Range ◽  
Polysaccharide Monooxygenases

Abstract Objective The development of an enzymatic assay for the specific quantification of the C1-oxidation product, i.e. gluconic acid of cellulose active lytic polysaccharide monooxygenases (LPMOs). Results In combination with a β-glucosidase, the spectrophotometrical assay can reliably quantify the specific C1- oxidation product of LPMOs acting on cellulose. It is applicable for a pure cellulose model substrate as well as lignocellulosic biomass. The enzymatic assay compares well with the quantification performed by HPAEC-PAD. In addition, we show that simple boiling is not sufficient to inactivate LPMOs and we suggest to apply a metal chelator in addition to boiling or to drastically increase pH for proper inactivation. Conclusions We conclude that the versatility of this simple enzymatic assay makes it useful in a wide range of experiments in basic and applied LPMO research and without the need for expensive instrumentation, e.g. HPAEC-PAD.

scholarly journals Translating surveillance data into incidence estimates

2019 ◽  
Vol 374 (1776) ◽  
pp. 20180262 ◽  
Author(s):  
Y. Bourhis ◽  
T. Gottwald ◽  
F. van den Bosch
Keyword(s):  
Infectious Disease ◽  
Disease Incidence ◽  
Disease Outbreaks ◽  
Estimation Methods ◽  
Estimation Model ◽  
Theme Issue ◽  
Online Application ◽  
Infectious Disease Outbreaks ◽  
Sampling Series ◽  
Wide Range

Monitoring a population for a disease requires the hosts to be sampled and tested for the pathogen. This results in sampling series from which we may estimate the disease incidence, i.e. the proportion of hosts infected. Existing estimation methods assume that disease incidence does not change between monitoring rounds, resulting in an underestimation of the disease incidence. In this paper, we develop an incidence estimation model accounting for epidemic growth with monitoring rounds that sample varying incidence. We also show how to accommodate the asymptomatic period that is the characteristic of most diseases. For practical use, we produce an approximation of the model, which is subsequently shown to be accurate for relevant epidemic and sampling parameters. Both the approximation and the full model are applied to stochastic spatial simulations of epidemics. The results prove their consistency for a very wide range of situations. The estimation model is made available as an online application. This article is part of the theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control’. This theme issue is linked with the earlier issue ‘Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes’.

scholarly journals Glass-on-Glass Fabrication of Bottle-Shaped Tunable Microlasers and their Applications

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Jonathan M. Ward ◽  
Yong Yang ◽  
Síle Nic Chormaic
Keyword(s):  
Gas Flow ◽  
60 Ghz ◽  
Melting Points ◽  
Simple Method ◽  
Flow Sensitivity ◽  
Whispering Gallery ◽  
Wide Range ◽  
Novel Method ◽  
Doped Glass ◽  
Lasing Modes

Abstract We describe a novel method for making microbottle-shaped lasers by using a CO2 laser to melt Er:Yb glass onto silica microcapillaries or fibres. This is realised by the fact that the two glasses have different melting points. The CO2 laser power is controlled to flow the doped glass around the silica cylinder. In the case of a capillary, the resulting geometry is a hollow, microbottle-shaped resonator. This is a simple method for fabricating a number of glass whispering gallery mode (WGM) lasers with a wide range of sizes on a single, micron-scale structure. The Er:Yb doped glass outer layer is pumped at 980 nm via a tapered optical fibre and WGM lasing is recorded around 1535 nm. This structure facilitates a new way to thermo-optically tune the microlaser modes by passing gas through the capillary. The cooling effect of the gas flow shifts the WGMs towards shorter wavelengths and thermal tuning of the lasing modes over 70 GHz is achieved. Results are fitted using the theory of hot wire anemometry, allowing the flow rate to be calibrated with a flow sensitivity as high as 72 GHz/sccm. Strain tuning of the microlaser modes by up to 60 GHz is also demonstrated.

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