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A Short History Of...
01 Jan 2013-
TL;DR: The history of the Church at Leiper's Fork, now known as Hillsboro, TN, has been discussed in this article, where it is suggested that it would be encouraging to the congregation if its history would be kept fresh in the minds of its members.
Abstract: There are very few people who have lived the allotted time but have an interesting biography, and there are very few congregations but have a very profitable history. The church at Leiper’s Fork, now known as Hillsboro, TN, has a most interesting history. There are few, if any, who know the history of their congregation. It seems that it would be encouraging to the congregation if its history would be kept fresh in the minds of its members.
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01 Jan 2015
TL;DR: Among the precursors used for the production of carbon fibers, polyacrylonitrile (PAN)-based and pitch-based precursor are the most important and many linear and cyclic polymers for carbon fibers are expected to open the door for the low-cost carbon fibers.
Abstract: In this chapter, we will present the precursors and manufacturing of carbon fibers. Among the precursors used for the production of carbon fibers, polyacrylonitrile (PAN)-based and pitch-based precursors are the most important. A significant amount of work has been done on relating the fiber structure to the properties and translating that relationship into production for either reducing cost or increasing fiber properties. However, challenges, including cost reduction, improvement in tensile and compressive strength, and alternative precursor development, still remain. We will also introduce many linear and cyclic polymers for carbon fibers, which are expected to open the door for the low-cost carbon fibers.
92 citations
19 Oct 2018
TL;DR: This paper aims to present a systematic review of the interactions between Big Data and cryptocurrency and serve as the one stop reference directory for researchers with regard to identifying research gaps and directing future explorations.
Abstract: Cryptocurrency has been a trending topic over the past decade, pooling tremendous technological power and attracting investments valued over trillions of dollars on a global scale. The cryptocurrency technology and its network have been endowed with many superior features due to its unique architecture, which also determined its worldwide efficiency, applicability and data intensive characteristics. This paper introduces and summarises the interactions between two significant concepts in the digitalized world, i.e., cryptocurrency and Big Data. Both subjects are at the forefront of technological research, and this paper focuses on their convergence and comprehensively reviews the very recent applications and developments after 2016. Accordingly, we aim to present a systematic review of the interactions between Big Data and cryptocurrency and serve as the one stop reference directory for researchers with regard to identifying research gaps and directing future explorations.
63 citations
TL;DR: The proposed iterative approach is a stochastic extension of the kNN density-based clustering method which randomly assigns objects to clusters by sampling a posterior class label distribution, and is shown to improve the correct classification rate in most experiments.
Abstract: We address the problem of unsupervised clustering of multidimensional data when the number of clusters is not known a priori. The proposed iterative approach is a stochastic extension of the $k {\rm NN}$ density-based clustering (knnclust) method which randomly assigns objects to clusters by sampling a posterior class label distribution. In our approach, contextual class-conditional distributions are estimated based on a $k$ nearest neighbors graph, and are iteratively modified to account for current cluster labeling. Posterior probabilities are also slightly reinforced to accelerate convergence to a stationary labeling. A stopping criterion based on the measure of clustering entropy is defined thanks to the Kozachenko-Leonenko differential entropy estimator, computed from current class-conditional entropies. One major advantage of our approach relies in its ability to provide an estimate of the number of clusters present in the data set. The application of our approach to the clustering of real hyperspectral image data is considered. Our algorithm is compared with other unsupervised clustering approaches, namely affinity propagation (ap), knnclust and Non Parametric Stochastic Expectation Maximization (npsem), and is shown to improve the correct classification rate in most experiments.
57 citations
TL;DR: A mechanistic investigation of the changes associated with distinct oxidation states of cobalt oximes and relevant for catalytic hydrogen generation.
Abstract: Three new heteroaxial cobalt oxime catalysts, namely [CoIII(prdioxH)(4tBupy)(Cl)]PF6 (1), [CoIII(prdioxH)(4Pyrpy)(Cl)]PF6 (2), and [CoIII(prdioxH)(4Bzpy)(Cl)]PF6 (3) have been studied. These species contain chloro and substituted tert-butyl/pyrrolidine/benzoyl-pyridino ligands axially coordinated to a trivalent cobalt ion bound to the N4-oxime macrocycle (2E,2'E,3E,3'E)-3,3'-(propane-1,3-diylbis(azanylylidene))bis(butan-2-one)dioxime, abbreviated (prdioxH)- in its monoprotonated form. Emphasis was given to the spectroscopic investigation of the coordination preferences and spin configurations among the different 3d6 CoIII, 3d7 CoII, and 3d8 CoI oxidation states of the metal, and to the catalytic proton reduction with an evaluation of the pathways for the generation of H2via CoIII-H- or CoII-H- intermediates by mono and bimetallic routes. The strong field imposed by the (prdioxH)- ligand precludes the existence of high-spin configurations, and 6-coordinate geometry is favored by the LSCoIII species. Species 1 and 3 show a split CoIII/CoII electrochemical wave associated with partial chemical conversion to a [CoIII(prdioxH)Cl2] species, whereas 2 shows a single event. The reduction of these CoIII complexes yields LSCoII and LSCoI species in which the pyridine acts as the dominant axial ligand. In the presence of protons, the catalytically active CoI species generates a CoIII-H- hydride species that reacts heterolytically with another proton to generate dihydrogen. The intermediacy of a trifluoroacetate-bound CoIII/CoII couple in the catalytic mechanism is proposed. These results allow for a generalization of the behavior of heteroaxial cobalt macrocycles and serve as guidelines for the development of new catalysts based on macrocyclic frameworks.
37 citations
TL;DR: Two self-assembled redox-active cages are presented and are constituted of 12 electro-active subunits that can be reversibly oxidized.
Abstract: Two self-assembled redox-active cages are presented. They are obtained by coordination-driven self-assembly of a tetra-pyridile tetrathiafulvalene ligand with cis-M(dppf)(OTf)2 (M = Pd or Pt; dppf = 1,1′-bis(diphenylphosphino)ferrocene; OTf = trifluoromethane-sulfonate) complexes. Both species are fully characterized and are constituted of 12 electro-active subunits that can be reversibly oxidized.
31 citations
References
More filters
01 Jan 2015
TL;DR: Among the precursors used for the production of carbon fibers, polyacrylonitrile (PAN)-based and pitch-based precursor are the most important and many linear and cyclic polymers for carbon fibers are expected to open the door for the low-cost carbon fibers.
Abstract: In this chapter, we will present the precursors and manufacturing of carbon fibers. Among the precursors used for the production of carbon fibers, polyacrylonitrile (PAN)-based and pitch-based precursors are the most important. A significant amount of work has been done on relating the fiber structure to the properties and translating that relationship into production for either reducing cost or increasing fiber properties. However, challenges, including cost reduction, improvement in tensile and compressive strength, and alternative precursor development, still remain. We will also introduce many linear and cyclic polymers for carbon fibers, which are expected to open the door for the low-cost carbon fibers.
92 citations
19 Oct 2018
TL;DR: This paper aims to present a systematic review of the interactions between Big Data and cryptocurrency and serve as the one stop reference directory for researchers with regard to identifying research gaps and directing future explorations.
Abstract: Cryptocurrency has been a trending topic over the past decade, pooling tremendous technological power and attracting investments valued over trillions of dollars on a global scale. The cryptocurrency technology and its network have been endowed with many superior features due to its unique architecture, which also determined its worldwide efficiency, applicability and data intensive characteristics. This paper introduces and summarises the interactions between two significant concepts in the digitalized world, i.e., cryptocurrency and Big Data. Both subjects are at the forefront of technological research, and this paper focuses on their convergence and comprehensively reviews the very recent applications and developments after 2016. Accordingly, we aim to present a systematic review of the interactions between Big Data and cryptocurrency and serve as the one stop reference directory for researchers with regard to identifying research gaps and directing future explorations.
63 citations
TL;DR: The proposed iterative approach is a stochastic extension of the kNN density-based clustering method which randomly assigns objects to clusters by sampling a posterior class label distribution, and is shown to improve the correct classification rate in most experiments.
Abstract: We address the problem of unsupervised clustering of multidimensional data when the number of clusters is not known a priori. The proposed iterative approach is a stochastic extension of the $k {\rm NN}$ density-based clustering (knnclust) method which randomly assigns objects to clusters by sampling a posterior class label distribution. In our approach, contextual class-conditional distributions are estimated based on a $k$ nearest neighbors graph, and are iteratively modified to account for current cluster labeling. Posterior probabilities are also slightly reinforced to accelerate convergence to a stationary labeling. A stopping criterion based on the measure of clustering entropy is defined thanks to the Kozachenko-Leonenko differential entropy estimator, computed from current class-conditional entropies. One major advantage of our approach relies in its ability to provide an estimate of the number of clusters present in the data set. The application of our approach to the clustering of real hyperspectral image data is considered. Our algorithm is compared with other unsupervised clustering approaches, namely affinity propagation (ap), knnclust and Non Parametric Stochastic Expectation Maximization (npsem), and is shown to improve the correct classification rate in most experiments.
57 citations
TL;DR: A mechanistic investigation of the changes associated with distinct oxidation states of cobalt oximes and relevant for catalytic hydrogen generation.
Abstract: Three new heteroaxial cobalt oxime catalysts, namely [CoIII(prdioxH)(4tBupy)(Cl)]PF6 (1), [CoIII(prdioxH)(4Pyrpy)(Cl)]PF6 (2), and [CoIII(prdioxH)(4Bzpy)(Cl)]PF6 (3) have been studied. These species contain chloro and substituted tert-butyl/pyrrolidine/benzoyl-pyridino ligands axially coordinated to a trivalent cobalt ion bound to the N4-oxime macrocycle (2E,2'E,3E,3'E)-3,3'-(propane-1,3-diylbis(azanylylidene))bis(butan-2-one)dioxime, abbreviated (prdioxH)- in its monoprotonated form. Emphasis was given to the spectroscopic investigation of the coordination preferences and spin configurations among the different 3d6 CoIII, 3d7 CoII, and 3d8 CoI oxidation states of the metal, and to the catalytic proton reduction with an evaluation of the pathways for the generation of H2via CoIII-H- or CoII-H- intermediates by mono and bimetallic routes. The strong field imposed by the (prdioxH)- ligand precludes the existence of high-spin configurations, and 6-coordinate geometry is favored by the LSCoIII species. Species 1 and 3 show a split CoIII/CoII electrochemical wave associated with partial chemical conversion to a [CoIII(prdioxH)Cl2] species, whereas 2 shows a single event. The reduction of these CoIII complexes yields LSCoII and LSCoI species in which the pyridine acts as the dominant axial ligand. In the presence of protons, the catalytically active CoI species generates a CoIII-H- hydride species that reacts heterolytically with another proton to generate dihydrogen. The intermediacy of a trifluoroacetate-bound CoIII/CoII couple in the catalytic mechanism is proposed. These results allow for a generalization of the behavior of heteroaxial cobalt macrocycles and serve as guidelines for the development of new catalysts based on macrocyclic frameworks.
37 citations
TL;DR: Two self-assembled redox-active cages are presented and are constituted of 12 electro-active subunits that can be reversibly oxidized.
Abstract: Two self-assembled redox-active cages are presented. They are obtained by coordination-driven self-assembly of a tetra-pyridile tetrathiafulvalene ligand with cis-M(dppf)(OTf)2 (M = Pd or Pt; dppf = 1,1′-bis(diphenylphosphino)ferrocene; OTf = trifluoromethane-sulfonate) complexes. Both species are fully characterized and are constituted of 12 electro-active subunits that can be reversibly oxidized.
31 citations