A new class of solution methods for multicomponent, multistage separation processes

1974 ◽  
Vol 52 (1) ◽  
pp. 52-63 ◽  
Author(s):  
J. F. Boston ◽  
S. L. Sullivan
Keyword(s):  
Separation Processes ◽  
New Class ◽  
Solution Methods

scholarly journals Lightning for Energy and Material Uses: A Structured Review

2020 ◽  
Author(s):  
Daniel S. Helman
Keyword(s):  
Lightning Discharge ◽  
Atmospheric Electricity ◽  
Dusty Plasmas ◽  
Biomass Energy ◽  
Separation Processes ◽  
New Class ◽  
Surface Charging ◽  
Oceanic Surface ◽  
Triggered Lightning ◽  
Early Translation

The average atmospheric charge density of Earth is neutral. Charge built up from thunderstorms and lightning phenomena is offset by oceanic surface charging, and offers a source of energy that has not been harnessed broadly. Unfortunately, the total terrestrial energy of the Earth’s atmospheric electrical system is modest (250–500 MW) compared to industrial requirements: Innovations are likely to offer improvements to societal efficiency rather than broad transformations. Direct capture systems located in places with very high occurrence of lightning discharge can generate ≈1 kWh per year on average. Material processing via triggered lightning is limited to techniques that utilize rapid discharges, e.g., metal and glass preprocessing of materials, waste volume reduction, biomass energy conversion, where current prices make plasma‐arc processes prohibitive. Triggered lightning may be used to assist blasting of mountain rock; or as a high‐voltage input for processes such as nuclear fusion. Passive collection of atmospheric electricity is modest but may be used in urban agriculture to increase biomass production. Thunderstorm charge‐separation processes suggest a new class of electricity generators based on kinetic energy and material collision. Ball lightning suggests additional research in dusty plasmas. These methods are all at proof‐of‐concept or early translation stages.

scholarly journals Colour-producing β-keratin nanofibres in blue penguin ( Eudyptula minor ) feathers

2011 ◽  
Vol 7 (4) ◽  
pp. 543-546 ◽  
Author(s):  
Liliana D'Alba ◽  
Vinodkumar Saranathan ◽  
Julia A. Clarke ◽  
Jakob A. Vinther ◽  
Richard O. Prum ◽  
...  
Keyword(s):  
Self Assembly ◽  
Coherent Scattering ◽  
Two Dimensional ◽  
Collagen Fibres ◽  
Separation Processes ◽  
New Class ◽  
X Ray Scattering ◽  
Absorption Of Light ◽  
Physical Interactions ◽  
Living Organisms

The colours of living organisms are produced by the differential absorption of light by pigments (e.g. carotenoids, melanins) and/or by the physical interactions of light with biological nanostructures, referred to as structural colours. Only two fundamental morphologies of non-iridescent nanostructures are known in feathers, and recent work has proposed that they self-assemble by intracellular phase separation processes. Here, we report a new biophotonic nanostructure in the non-iridescent blue feather barbs of blue penguins ( Eudyptula minor ) composed of parallel β-keratin nanofibres organized into densely packed bundles. Synchrotron small angle X-ray scattering and two-dimensional Fourier analysis of electron micrographs of the barb nanostructure revealed short-range order in the organization of fibres at the appropriate size scale needed to produce the observed colour by coherent scattering. These two-dimensional quasi-ordered penguin nanostructures are convergent with similar arrays of parallel collagen fibres in avian and mammalian skin, but constitute a novel morphology for feathers. The identification of a new class of β-keratin nanostructures adds significantly to the known mechanisms of colour production in birds and suggests additional complexity in their self-assembly.

Solution Methods for a New Class of Simple Model Neurons

2007 ◽  
Vol 19 (12) ◽  
pp. 3216-3225 ◽  
Author(s):  
Mark D. Humphries ◽  
Kevin Gurney
Keyword(s):  
Simple Model ◽  
Neuron Model ◽  
Solution Method ◽  
Cortical Cell ◽  
Spike Generation ◽  
Firing Patterns ◽  
New Class ◽  
Efficient Simulation ◽  
Different Types ◽  
Solution Methods

Izhikevich (2003) proposed a new canonical neuron model of spike generation. The model was surprisingly simple yet able to accurately replicate the firing patterns of different types of cortical cell. Here, we derive a solution method that allows efficient simulation of the model.

scholarly journals On the Riemann Function

Mathematics ◽  
2018 ◽  
Vol 6 (12) ◽  
pp. 316
Author(s):  
Peter Zeitsch
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Governing Equation ◽  
Symmetry Algebra ◽  
Riemann Function ◽  
Original Study ◽  
Hyperbolic Partial Differential Equation ◽  
Order Linear ◽  
New Class ◽  
Solution Methods

Riemann’s method is one of the definitive ways of solving Cauchy’s problem for a second order linear hyperbolic partial differential equation in two variables. The first review of Riemann’s method was published by E.T. Copson in 1958. This study extends that work. Firstly, three solution methods were overlooked in Copson’s original paper. Secondly, several new approaches for finding Riemann functions have been developed since 1958. Those techniques are included here and placed in the context of Copson’s original study. There are also numerous equivalences between Riemann functions that have not previously been identified in the literature. Those links are clarified here by showing that many known Riemann functions are often equivalent due to the governing equation admitting a symmetry algebra isomorphic to S L ( 2 , R ) . Alternatively, the equation admits a Lie-Bäcklund symmetry algebra. Combining the results from several methods, a new class of Riemann functions is then derived which admits no symmetries whatsoever.

scholarly journals On The Riemann Function

2018 ◽  
Author(s):  
Peter J. Zeitsch
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Governing Equation ◽  
Symmetry Algebra ◽  
Riemann Function ◽  
Original Study ◽  
Hyperbolic Partial Differential Equation ◽  
Order Linear ◽  
New Class ◽  
Solution Methods

Riemann’s method is one of the definitive ways of solving Cauchy’s problem for a second order linear hyperbolic partial differential equation in two variables. The first review of Riemann’s method was published by E. T. Copson in 1958. This study extends that work. Firstly, three solution methods were overlooked in Copson’s original paper. Secondly, several new approaches for finding Riemann functions have been developed since 1958. Those techniques are included here and placed in the context of Copson’s original study. There are also numerous equivalences between Riemann functions that have not previously been identified in the literature. Those links are clarified here by showing that many known Riemann functions are often equivalent due to the governing equation admitting a symmetry algebra isomorphic to $SL(2,R)$. Alternatively, the equation admits a Lie-Bäcklund symmetry algebra. Combining the results from several methods, a new class of Riemann functions is then derived which admits no symmetries whatsoever.

A SEM/TEM examination of a ceramic membrane

1986 ◽  
Vol 44 ◽  
pp. 682-683
Author(s):  
C.E. Voegele-Kliewer ◽  
A.D. McMaster ◽  
G.W. Dirks
Keyword(s):  
Electron Microscopy ◽  
Gas Separation ◽  
Ceramic Membrane ◽  
Hydrogen Iodide ◽  
Separation Processes ◽  
Corning Glass ◽  
Gas Transport Properties ◽  
Porous Microstructure ◽  
Microscopy Techniques ◽  
The Relationship

Materials other than polymers, e.g. ceramic silicates, are currently being investigated for gas separation processes. The permeation characteristics of one such material, Vycor (Corning Glass #1370), have been reported for the separation of hydrogen from hydrogen iodide. This paper will describe the electron microscopy techniques applied to reveal the porous microstructure of a Vycor membrane. The application of these techniques has led to an increased understanding in the relationship between the substructure and the gas transport properties of this material.

In Situ microscopy of the anodic etching of silicon

1995 ◽  
Vol 53 ◽  
pp. 232-233
Author(s):  
Frances M. Ross ◽  
Peter C. Searson
Keyword(s):  
Composite Structures ◽  
High Surface ◽  
High Surface Area ◽  
Chemical Properties ◽  
Selective Etching ◽  
Silicon On Insulator ◽  
Second Phase ◽  
Porous Layers ◽  
New Class ◽  
Porous Semiconductors

Porous semiconductors represent a relatively new class of materials formed by the selective etching of a single or polycrystalline substrate. Although porous silicon has received considerable attention due to its novel optical properties1, porous layers can be formed in other semiconductors such as GaAs and GaP. These materials are characterised by very high surface area and by electrical, optical and chemical properties that may differ considerably from bulk. The properties depend on the pore morphology, which can be controlled by adjusting the processing conditions and the dopant concentration. A number of novel structures can be fabricated using selective etching. For example, self-supporting membranes can be made by growing pores through a wafer, films with modulated pore structure can be fabricated by varying the applied potential during growth, composite structures can be prepared by depositing a second phase into the pores and silicon-on-insulator structures can be formed by oxidising a buried porous layer. In all these applications the ability to grow nanostructures controllably is critical.

The microtubule associated protein (MAP) tau forms a new class of triple-stranded left-hand helical fibrous protein polymer

1992 ◽  
Vol 50 (1) ◽  
pp. 540-541
Author(s):  
G. C. Ruben ◽  
K. Iqbal ◽  
I. Grundke-Iqbal ◽  
H. Wisniewski ◽  
T. L. Ciardelli ◽  
...  
Keyword(s):  
Axial Ratio ◽  
Normal Structure ◽  
Paired Helical Filaments ◽  
Left Hand ◽  
New Class ◽  
Protein Polymer ◽  
Fibrous Protein ◽  
Protein Map ◽  
Neurotransmitter Transport ◽  
Alzheimer Neurofibrillary Tangles

In neurons, the microtubule associated protein, tau, is found in the axons. Tau stabilizes the microtubules required for neurotransmitter transport to the axonal terminal. Since tau has been found in both Alzheimer neurofibrillary tangles (NFT) and in paired helical filaments (PHF), the study of tau's normal structure had to preceed TEM studies of NFT and PHF. The structure of tau was first studied by ultracentrifugation. This work suggested that it was a rod shaped molecule with an axial ratio of 20:1. More recently, paraciystals of phosphorylated and nonphosphoiylated tau have been reported. Phosphorylated tau was 90-95 nm in length and 3-6 nm in diameter where as nonphosphorylated tau was 69-75 nm in length. A shorter length of 30 nm was reported for undamaged tau indicating that it is an extremely flexible molecule. Tau was also studied in relation to microtubules, and its length was found to be 56.1±14.1 nm.

Study of segregation in La1.8Sr0.2CuO4 superconductor by STEM-EDS microanalysis

1987 ◽  
Vol 45 ◽  
pp. 54-55
Author(s):  
T. F. Kelly ◽  
P. J. Lee ◽  
E. E. Hellstrom ◽  
D. C. Larbalestier
Keyword(s):  
Rare Earth ◽  
High Field ◽  
Transport Current ◽  
Total Thickness ◽  
New Class ◽  
Ceramic Superconductors ◽  
Current Densities ◽  
Group Ii ◽  
Eds Microanalysis

Recently there has been much excitement over a new class of high Tc (>30 K) ceramic superconductors of the form A1-xBxCuO4-x, where A is a rare earth and B is from Group II. Unfortunately these materials have only been able to support small transport current densities 1-10 A/cm2. It is very desirable to increase these values by 2 to 3 orders of magnitude for useful high field applications. The reason for these small transport currents is as yet unknown. Evidence has, however, been presented for superconducting clusters on a 50-100 nm scale and on a 1-3 μm scale. We therefore planned a detailed TEM and STEM microanalysis study in order to see whether any evidence for the clusters could be seen.A La1.8Sr0.2Cu04 pellet was cut into 1 mm thick slices from which 3 mm discs were cut. The discs were subsequently mechanically ground to 100 μm total thickness and dimpled to 20 μm thickness at the center.

Electronic structure studies of conducting polymers by electron energy-loss spectroscopy

1996 ◽  
Vol 54 ◽  
pp. 160-161
Author(s):  
J. Fink
Keyword(s):  
Electronic Structure ◽  
Conducting Polymers ◽  
Conjugated Polymers ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Light Emitting ◽  
One Dimensional ◽  
New Class ◽  
Electrical Conductivities ◽  
Electron Energy Loss

Conducting polymers comprises a new class of materials achieving electrical conductivities which rival those of the best metals. The parent compounds (conjugated polymers) are quasi-one-dimensional semiconductors. These polymers can be doped by electron acceptors or electron donors. The prototype of these materials is polyacetylene (PA). There are various other conjugated polymers such as polyparaphenylene, polyphenylenevinylene, polypoyrrole or polythiophene. The doped systems, i.e. the conducting polymers, have intersting potential technological applications such as replacement of conventional metals in electronic shielding and antistatic equipment, rechargable batteries, and flexible light emitting diodes.Although these systems have been investigated almost 20 years, the electronic structure of the doped metallic systems is not clear and even the reason for the gap in undoped semiconducting systems is under discussion.

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