Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2019 ( 14 )

2018 ( 89 )

2017 ( 87 )

2016 ( 110 )

Custom range...

Search Results: 1 - 10 of 32655 matches for " Daniel Forchheim "
All listed articles are free for downloading (OA Articles)
Page 1 /32655
Display every page Item
Influence of RANEY Nickel on the Formation of Intermediates in the Degradation of Lignin
Daniel Forchheim,Ursel Hornung,Philipp Kempe,Andrea Kruse,David Steinbach
International Journal of Chemical Engineering , 2012, DOI: 10.1155/2012/589749
Abstract: Lignin forms an important part of lignocellulosic biomass and is an abundantly available residue. It is a potential renewable source of phenol. Liquefaction of enzymatic hydrolysis lignin as well as catalytical hydrodeoxygenation of the main intermediates in the degradation of lignin, that is, catechol and guaiacol, was studied. The cleavage of the ether bonds, which are abundant in the molecular structure of lignin, can be realised in near-critical water (573 to 673?K, 20 to 30?MPa). Hydrothermal treatment in this context provides high selectivity in respect to hydroxybenzenes, especially catechol. RANEY Nickel was found to be an adequate catalyst for hydrodeoxygenation. Although it does not influence the cleavage of ether bonds, RANEY Nickel favours the production of phenol from both lignin and catechol. The main product from hydrodeoxygenation of guaiacol with RANEY Nickel was cyclohexanol. Reaction mechanism and kinetics of the degradation of guaiacol were explored. 1. Introduction Earth?s resources of crude oil are limited [1]. An important challenge for scientists and engineers is to develop technologies that are largely independent from fossil crude oils. Biomass, especially organic waste material, has a high potential to replace crude oil as a basic input material for the production of many organic chemicals. Lignocellulosic biomass is one of the most abundant renewable organic materials in the world. Lignin, a major component of lignocellulosic biomass, is mostly available as waste material. The paper industry produces more than 50 million tons of dry lignin every year worldwide [2]. It is mainly burned to recover its energetic value. Lignin has a structure similar to brown coal, being an aromatic heteropolymer. The three basic building blocks, p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol. are interlinked by C–C or ether bonds. The latter is the weaker one of the two bonds mentioned and thus of high interest for lignin degradation. As lignin is relatively resistant to chemical or enzymatic degradation, harsh reaction conditions are required to break down this polymer [3]. By cleavage of the ether bonds, aromatic monomers are formed. Thus lignin provides high potential to serve as a renewable source for phenol or benzene [4]. Phenol is extremely interesting as building block for synthetic polymers, resins, and epoxy- or polyurethane [3]. It is however a challenge to gain a high-value product from a chemically complicated and inhomogeneous component as lignin. In order to do so, char formation is to be avoided. Char formation can be
Poetry Teaching and Multimodality: Theory into Practice  [PDF]
Daniel Xerri
Creative Education (CE) , 2012, DOI: 10.4236/ce.2012.34077
Abstract: This article discusses the theoretical concepts underpinning a multimodal approach to poetry teaching and considers a number of ways in which this can be adopted in practice. It discusses what is entailed by the concept of multimodality and examines the claims made about the benefits of employing a multimodal approach. It reviews the literature on multimodality and examines how teachers may blend a variety of techniques and resources in order not just to engage their students with poetry but also to activate language learning. In particular, this article examines how by tapping students’ visual and digital literacy skills they are enabled to create video poems, podcasts, hypertexts and wikis, all of which represent new ways of using language and experiencing poetry. Through constant reference to the research carried out so far, this article seeks to show how by means of a multimodal approach poetry can act as a springboard for the development of students’ language proficiency and creative engagement.
Mathematical Derivation of Angular Momenta in Quantum Physics  [PDF]
Daniel Grucker
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.47125

For a two-dimensional complex vector space, the spin matrices can be calculated directly from the angular momentum commutator definition. The 3 Pauli matrices are retrieved and 23 other triplet solutions are found. In the three-dimensional space, we show that no matrix fulfills the spin equations and preserves the norm of the vectors. By using a Clifford geometric algebra it is possible in the four-dimensional spacetime (STA) to retrieve the 24 different spins 1/2. In this framework, spins 1/2 are rotations characterized by multivectors composed of 3 vectors and 3 bivectors. Spins 1 can be defined as rotations characterized by 4 vectors, 6 bivectors and 4 trivectors which result in unit multivectors which preserve the norm. Let us note that this simple derivation retrieves the main spin properties of particle physics.

Contribution of Vertical Farms to Increase the Overall Energy Efficiency of Urban Agglomerations  [PDF]
Podmirseg Daniel
Journal of Power and Energy Engineering (JPEE) , 2014, DOI: 10.4236/jpee.2014.24013
Abstract: The 21st century keeps huge challenges for the system “city”. Shortage of resources and world population growth forces architects to think in spaces with increasingly more structural linkages. No era has shaped the system of a city like the oil age did. Its grown structures are dependent from cheap and easy to produce petroleum. The postmodern city, facing the end of cheap and abundant oil, is now dependent from this finite resource. To minimize the dependency from hydrocarbon energy it is necessary to increase urban density, to switch to renewable energy production and to create new spaces for multifunctional purposes. An essential problem of urban agglomeration, though, is the fact that distances between food production and consumption have increased drastically in the last fifty years. Cheap oil made it possible to implement a global food transportation
network and it also supported intensive monocultural food production. Today’s food no more gets bought from local markets, but from labels. Its value is dependent from the brand-image, represented from the tertiary sector. The end of cheap fossil fuels carries a huge potential for architects and urban planners—we can move away from representing abstract, non-spatial processes and identities but creating spaces for dynamic local interactions. A promising typus for this might be the Vertical Farm.
The Computational Theory of Intelligence: Information Entropy  [PDF]
Daniel Kovach
International Journal of Modern Nonlinear Theory and Application (IJMNTA) , 2014, DOI: 10.4236/ijmnta.2014.34020
Abstract: This paper presents an information theoretic approach to the concept of intelligence in the computational sense. We introduce a probabilistic framework from which computation alintelligence is shown to be an entropy minimizing process at the local level. Using this new scheme, we develop a simple data driven clustering example and discuss its applications.
The Computational Theory of Intelligence: Applications to Genetic Programming and Turing Machines  [PDF]
Daniel Kovach
International Journal of Modern Nonlinear Theory and Application (IJMNTA) , 2015, DOI: 10.4236/ijmnta.2015.41002

In this paper, we continue the efforts of the Computational Theory of Intelligence (CTI) by extending concepts to include computational processes in terms of Genetic Algorithms (GA’s) and Turing Machines (TM’s). Active, Passive, and Hybrid Computational Intelligence processes are also introduced and discussed. We consider the ramifications of the assumptions of CTI with regard to the qualities of reproduction and virility. Applications to Biology, Computer Science and Cyber Security are also discussed.

On Hypercomplex Extensions of Quantum Theory  [PDF]
Daniel Sepunaru
Journal of Modern Physics (JMP) , 2015, DOI: 10.4236/jmp.2015.65075
Abstract: This paper discusses quantum mechanical schemas for describing waves with non-abelian phases, Fock spaces of annihilation-creation operators for these structures, and the Feynman recipe for obtaining descriptions of particle interactions with external fields.
A Vector Matrices Realization of Hurwitz Algebras  [PDF]
Daniel Sepunaru
Journal of Modern Physics (JMP) , 2018, DOI: 10.4236/jmp.2018.914151
Abstract: We present here a realization of Hurwitz algebra in terms of 2 × 2 vector matrices which maintain the correspondence between the geometry of vector spaces that is used in the classical physics and the algebraic foundation underlying quantum theory. The multiplication rule we use is a modification of the one originally introduced by M. Zorn. We demonstrate that our multiplication is not intrinsically non-associative; the realization of the real and complex numbers is commutative and associative, the real quaternions maintain associativity and the real octonion matrices form an alternative algebra. Extension to the calculus of the matrices (with Hurwitz algebra valued matrix elements) of the arbitrary dimensions is straightforward. We briefly discuss applications of the obtained results to extensions of standard Hilbert space formulation in quantum physics and to alternative wave mechanical formulation of the classical field theory.
On the Problem of Eigenschaften in Quantum and Classical Mechanics  [PDF]
Daniel Sepunaru
Journal of Modern Physics (JMP) , 2018, DOI: 10.4236/jmp.2018.914152
Abstract: We argue that in contrast to the classical physics, measurements in quantum mechanics should provide simultaneous information about all relevant relative amplitudes (pure states and the transitions between them) and all relevant relative phases. Simultaneity is needed since measurement changes the state of the system (in both quantum and in classical physics). We call that measurement procedure holographic detection. Mathematically, it is described by a set of mutually commuting selfadjoint operators that are similar and closely related to projections. We present explicit examples and discuss general features of the corresponding experimental setup which we identify as the quantum reference frame.
Enhanced Frequency Resolution in Data Analysis  [PDF]
Luca Perotti, Daniel Vrinceanu, Daniel Bessis
American Journal of Computational Mathematics (AJCM) , 2013, DOI: 10.4236/ajcm.2013.33034

We present a numerical study of the resolution power of Padé Approximations to the Z-transform, compared to the Fourier transform. As signals are represented as isolated poles of the Padé Approximant to the Z-transform, resolution depends on the relative position of signal poles in the complex plane i.e. not only the difference in frequency (separation in angular position) but also the difference in the decay constant (separation in radial position) contributes to the resolution. The frequency resolution increase reported by other authors is therefore an upper limit: in the case of signals with different decay rates frequency resolution can be further increased.

Page 1 /32655
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.