An exploration of key information models and their relationships in global manufacturing decision support

Global manufacturing businesses are beginning to benefit from the information and knowledge support provided by modern IT tools such as Product Lifecycle Management (PLM), Enterprise Resource Planning (ERP), and Customer Relations Management (CRM). Many types of information and knowledge, from customer requirements through product information to global enterprise manufacturing capability are involved in global manufacturing decisions. Understanding the appropriate structures and relationships for this information and knowledge is a significant issue if effective wide-ranging support is to be provided. This paper focuses on global manufacturing decision support and explores three key types of information and knowledge relationship: (a) relationships between information and knowledge elements within a single information and knowledge model; (b) relationships between different information and knowledge models at one organizational level; (c) relationships between different information and knowledge models at different organizational levels. The corresponding information and knowledge structures have been presented with Unified Modelling Language (UML) to show the multiplicity of relationship required, and these are explored with an experimental system based on Rational Unified Process, Visual C++, and object-oriented DBMS ObjectStore. A case study has been pursued to explore the application of the information and knowledge models to a real industry environment

Hafnium and Zirconium Complexes Bearing ONN-Tridentate Ligands and Their Catalytic Properties toward Olefin Polymerization

The development of high-performance catalysts is a goal that is constantly being pursued in the field of polyolefins. In this study, a class of Hf (Hf1 and Hf2) and Zr (Zr1 and Zr2) dimethyl complexes were prepared by one-pot reactions of phenoxy-imino-quinoline compounds with MMe4 (M = Hf and Zr). Both NMR spectroscopy and X-ray studies suggested the formation of phenoxy-amido-quinoline metal complexes because of methyl migration from the metal center to the carbon atom of imine. These Hf and Zr complexes exhibited moderate to high activity (up to 9060 kg (PE)·mol–1(M)·h–1) toward ethylene homopolymerization and copolymerization with 1-octene in the presence of 1 equiv of [Ph3C][B(C6F5)4] as a cocatalyst. It was significant that Zr complexes were far more active than Hf complexes bearing the same ligand under otherwise identical conditions, revealing a tremendous metal center effect on catalysis. On the other hand, the nature of the ligand also strongly influenced the catalytic properties, including the activity and properties, of resultant polymers. Thus, Zr complex Zr1 with a sterically demanding and electron-donating Me group on the 2-position of quinoline showed the highest activity and good thermal stability

Dinuclear Group 4 Metal Complexes Bearing Anthracene-Bridged Bifunctional Amido-Ether Ligands: Remarkable Metal Effect and Cooperativity toward Ethylene/1-Octene Copolymerization

Two types of bifunctional amido-ether ligands (syn-L and anti-L) with the rigid anthracene skeleton were designed to support dinuclear group 4 metal complexes. All organic ligands and organometallic complexes (syn-M2 and anti-M2; M = Hf, Zr, and Ti) were fully characterized by 1H and 13C NMR spectroscopies and elemental analyses. The anti-Hf2 complex showed two confirmations at room temperature with C2-symmetry or S2-symmetry that can inter-exchange, as indicated by VT NMR, while only a C2-symmetric isomer was observed for syn-Hf2 complex at room temperature. However, for Zr and Ti analogues, both syn and anti complexes exhibited only one conformation at room temperature. The molecular structures of complexes syn-Hf2, anti-Hf2, and syn-Ti2 in the solid state were further determined by single-crystal X-ray diffraction, revealing the distances between two metal centers in syn-M2 from 7.138 Å (syn-Ti2) to 7.321 Å (syn-Hf2) but a much farther separation in anti-M2 (8.807 Å in C2-symmetric anti-Hf2). The mononuclear complex (2-CH3O–C6H4–N–C14H9)Zr(NMe2)3 (mono-Zr1) was also prepared for control experiments. In the presence of alkyl aluminum (AlEt3) as the alkylating agent and trityl borate ([Ph3C][B(C6F5)4]) as the co-catalyst, all metal complexes were tested for copolymerization of ethylene with 1-octene at high temperature (130 °C). The preliminary polymerization results revealed that the activity was highly dependent upon the nature of metal centers, and syn-Zr2 showed the highest activity of 9600 kg(PE)·mol–1 (Zr)·h–1, which was about 17- and 2.2-fold higher than those of syn-Hf2 and syn-Ti2, respectively. Benefitting from both steric proximity and electronical interaction of two metal centers, syn-Zr2 exhibited significant cooperativity in comparison to anti-Zr2 and mono-Zr1, with regard to activity and molecular weight and 1-octene incorporation of resultant copolymers

A 1D Helical Ni(II) Coordination Polymer Based on Butylphenyl Imidazole Dicarboxylate

<div><p>Solvothermal reaction of nitrate salt with a multifunctional organic ligand, 2-(<i>p-tert-</i>butylphenyl)-1<i>H</i>-imidazole-4,5-dicarboxylic acid (<i>p</i>-H₃BuPhIDC), leads to a novel 1-D helical chain coordination polymer, {[Ni₄(μ<i>₂</i>-<i>p</i>-HBuPhIDC)₄(H₂O)₄]·H₂O}_n (1), which has been characterized by single-crystal X-ray diffraction, spectroscopy, and elemental analysis. The thermal and photoluminescent properties of polymer 1 have been investigated as well.</p></div

Dinuclear Group 4 Metal Complexes Bearing Anthracene-Bridged Bifunctional Amido-Ether Ligands: Remarkable Metal Effect and Cooperativity toward Ethylene/1-Octene Copolymerization

Two types of bifunctional amido-ether ligands (syn-L and anti-L) with the rigid anthracene skeleton were designed to support dinuclear group 4 metal complexes. All organic ligands and organometallic complexes (syn-M2 and anti-M2; M = Hf, Zr, and Ti) were fully characterized by 1H and 13C NMR spectroscopies and elemental analyses. The anti-Hf2 complex showed two confirmations at room temperature with C2-symmetry or S2-symmetry that can inter-exchange, as indicated by VT NMR, while only a C2-symmetric isomer was observed for syn-Hf2 complex at room temperature. However, for Zr and Ti analogues, both syn and anti complexes exhibited only one conformation at room temperature. The molecular structures of complexes syn-Hf2, anti-Hf2, and syn-Ti2 in the solid state were further determined by single-crystal X-ray diffraction, revealing the distances between two metal centers in syn-M2 from 7.138 Å (syn-Ti2) to 7.321 Å (syn-Hf2) but a much farther separation in anti-M2 (8.807 Å in C2-symmetric anti-Hf2). The mononuclear complex (2-CH3O–C6H4–N–C14H9)Zr(NMe2)3 (mono-Zr1) was also prepared for control experiments. In the presence of alkyl aluminum (AlEt3) as the alkylating agent and trityl borate ([Ph3C][B(C6F5)4]) as the co-catalyst, all metal complexes were tested for copolymerization of ethylene with 1-octene at high temperature (130 °C). The preliminary polymerization results revealed that the activity was highly dependent upon the nature of metal centers, and syn-Zr2 showed the highest activity of 9600 kg(PE)·mol–1 (Zr)·h–1, which was about 17- and 2.2-fold higher than those of syn-Hf2 and syn-Ti2, respectively. Benefitting from both steric proximity and electronical interaction of two metal centers, syn-Zr2 exhibited significant cooperativity in comparison to anti-Zr2 and mono-Zr1, with regard to activity and molecular weight and 1-octene incorporation of resultant copolymers

Stereoselective Ring-Opening Polymerization of <i>rac</i>-Lactide Using Organocatalytic Cyclic Trimeric Phosphazene Base

Phosphazene base is an important organocatalyst in polymer chemistry owing to its high activity and versatility. In this contribution, we demonstrate that cyclic trimeric phosphazene base (<b>CTPB</b>) can catalyze stereoselective ring-opening polymerization (ROP) of <i>rac</i>-lactide (<i>rac</i>-LA) to produce isotactic stereoblock PLA (<i>P</i>_i up to 0.93). The polymerizations are highly controlled, as evidenced by linear relationship between molecular weights (MW) and monomer conversions and the narrow dispersity (<i>Đ</i> = <i>M</i>_w/<i>M</i>_n) of the resulted polymers with high fidelity of end groups. The investigations on polymerization parameters show that the tacticity of produced PLA depends on the polymerization temperatures and solvents, while the kinetic studies reveal a faster rate for ROP of l-LA as compared to <i>rac</i>-LA under same conditions. Based on these results, the chain end control mechanism is proposed to explain the production of isotactic stereoblock PLA from <i>rac</i>-LA by an achiral catalyst

Stratigraphic records of the dynamic uplift of the Emeishan large igneous province

<div><p></p><p>Fluid dynamical and numerical modelling predicts a large-scale regional domal uplift prior to basalt eruptions in large igneous provinces, which can be readily measured when a plume head rises below a shallow marine sedimentary basin. Research on the sedimentology, biostratigraphy, and isotopic chronology of the Emeishan large igneous province demonstrates that the sedimentary environment in the Maokou stage is not uniform carbonate platform facies, but rather sedimentary facies with a north–south linear alignment and west–east different distribution controlled by the syn-depositional normal faulting of the Changhai and Xiaojiang faults, which are the result of underwater dynamic uplift induced by deep mantle activity. The dynamic uplift started in the Maokou stage. Thus, thinning of the Maokou limestone was the product of the difference in the initial depositional thickness caused by the underwater uplift and post-depositional surface uplift and erosion, but post-depositional uplift was much less than kilometre scale. Sedimentary facies differentiation and tectonic–sedimentary evolution in the Maokou stage provide a constraint for the time of the initial eruption and eruption environment before and during the Emeishan basalt eruption. Small-scale magmatic activity might have already begun in the middle of the Maokou stage, whereas submarine and terrestrial sedimentary environments coexisted before and during Emeishan basalt eruption.</p></div

Synthesis, Characterization, and Heterobimetallic Cooperation in a Titanium–Chromium Catalyst for Highly Branched Polyethylenes

A heterobimetallic catalyst, <b>{Ti--Cr}</b>, consisting of a constrained-geometry titanium olefin polymerization center (<b>CGC^EtTi</b>) covalently linked to a chromium bis­(thioether)­amine ethylene trimerization center (<b>SNSCr</b>) was synthesized and fully characterized. In ethylene homopolymerizations it affords linear low-density polyethylene with molecular weights as high as 460 kg·mol^–1 and exclusively <i>n</i>-butyl branches in conversion-insensitive densities of ∼18 branches/1000 carbon atoms, which are ∼17 and ∼3 times (conversion-dependent), respectively, those achieved by tandem mononuclear <b>CGC^EtTi</b> and <b>SNSCr</b> catalysts under identical reaction conditions

Editorial: fake news, misinformation, and supply chain disruptions: the role of emerging technologies

Editorial: fake news, misinformation, and supply chain disruptions: the role of emerging technologies.</p

Synthesis, Characterization, and Heterobimetallic Cooperation in a Titanium–Chromium Catalyst for Highly Branched Polyethylenes

A heterobimetallic catalyst, <b>{Ti--Cr}</b>, consisting of a constrained-geometry titanium olefin polymerization center (<b>CGC^EtTi</b>) covalently linked to a chromium bis­(thioether)­amine ethylene trimerization center (<b>SNSCr</b>) was synthesized and fully characterized. In ethylene homopolymerizations it affords linear low-density polyethylene with molecular weights as high as 460 kg·mol^–1 and exclusively <i>n</i>-butyl branches in conversion-insensitive densities of ∼18 branches/1000 carbon atoms, which are ∼17 and ∼3 times (conversion-dependent), respectively, those achieved by tandem mononuclear <b>CGC^EtTi</b> and <b>SNSCr</b> catalysts under identical reaction conditions