Search results for "NUMB"

Dual Substituent Parameter Modeling of Theoretical, NMR and IR Spectral Data of 5-Substituted Indole-2,3-diones

2002

Correlations of AM1 and PM3 theoretical data, 13C-NMR substituent chemical shifts (13C-SCS) and IR carbonyl group wave numbers [ν(C3â•ÂO)] were studied using dual substituent parameter (DSP) models for 5-substituted indole-2,3-diones. For the C7 atom a reverse substituent effect attributed to extended À-polarization was observed. On the other hand, the DSP approaches for the C3 atom showed normal substituent effects with some contribution of reverse effect supported strongly by 13C-SCS correlations. In the ν(C3â•ÂO) and p(C3â•ÂO) DSP correlations the field effect contribution predominates over the resonance effect, which justifies the using of earlier suggested vibrational cou…

Valence Topological Charge-Transfer Indices for Reflecting Polarity: Correction for Heteromolecules

2005

Valence topological charge-transfer (CT) indices are applied to the calculation of dipole moments mu. The mu calculated by algebraic and vector semisums of the CT indices are defined. The model is generalized for molecules with heteroatoms and corrected for sp(3)-heteromolecules. The ability of the indices for the description of the molecular charge distribution is established by comparing them with mu of the valence-isoelectronic series of cyclopentadiene, benzene and styrene. Two CT indices, mu(vec) (vector semisum of vertex-pair mu) and mu(vec)V (valence mu(vec)) are proposed. The mu(vec) behaviour is intermediate between mu(vec) and mu(experiment). The correction is produced in the corr…

Tin( II ) and Lead( II ) 4‐Acyl‐5‐pyrazolonates: Synthesis, Spectroscopic and X‐ray Structural Characterization

2004

Novel tin(II) β-diketonate Sn(Q)2 complexes [HQ = 1-R1-3-R3-4-R4(C=O)-pyrazol-5-one; HQC: R1 = Ph, R3 = Me, R4 = Cy; HQS: R1 = Ph, R3 = Me, R4 = CHPh2; HQL: R1 = Ph, R3 = Me, R4 = CH2Ph; HQT: R1 = Ph, R3 = Me, R4 = CH2tBu; HQE: R1 = Ph, R3 = Me, R4 = Et; HQB: R1 = Ph, R3 = Me, R4 = tBu; HQW: R1 = Ph, R3 = Me, R4 = p-(tBu)Ph; HQR: R1 = Ph, R3 = Me, R4 = p-[(CH2)5CH3]Ph; HQN: R1 = p-NO2Ph, R3 = Me, R4 = Ph; HQM: R1 = Me, R3 = Me, R4 = Ph; HQD: R1 = Me, R3 = Me, R4 = Me; HQP: R1 = Ph, R3 = Ph, R4 = Ph; HQG: R1 = Ph, R3 = Ph, R4 = Me; HQF: R1 = p-CF3Ph, R3 = Me, R4 = Ph; HQH: R1 = p-CF3Ph, R3 = Me, R4 = Me] have been isolated and characterized by single-crystal X-ray diffraction analyses, IR, 1…

Heisenberg picture in the description of simplified stock markets

2008

Mixed mode energy release rates for bonded composite joints

2011

Abstract: Analytical formulae developed by Luo and Tong (2009) to determine the mixed mode strain energy release rates of laminated and co-cured composite structures and joints are reviewed. The effects of varying loading conditions and geometries on the mode mixity found analytically are investigated via a parametric study. A critical evaluation of the analytical formulae indicates that the formulae are robust in calculating the total strain energy release rate, but may underestimate the mode II component compared with the finite element analysis and experimental results. Possible reasons for this discrepancy are discussed, including the effect of stress concentrations and singularities at…

Rapid prototyping for micro-engineering and microfluidic applications: Recycled pmma, a sustainable substrate material

2018

Poly(methylmethacrylate), PMMA, is one of the most commonly used thermoplastics for the manufacture of micromechanical and microfluidic devices, due to its optical transparency, rigid mechanical properties, low cost and good workability in conjunction with its rapid prototyping and mass manufacturing. Recent advances in the rapid-prototyping fields have allowed the production of precise features compatible with microfluidic structures and accelerated the conversion process from bench-side to mass market. For example, to address the need for fast design cycles using material compatible with mass manufacturing, we have developed an ultrafast prototyping technique for the manufacture of multil…

Advances in Strain Gauge Measurement on Composite Materials

2010

Abstract:  This article gives an overview on the application of strain gauge techniques to the analysis of the strains in composite materials. The orthotropic behaviour of the composite influences the performance of strain gauges that are calibrated for use on isotropic materials. The article considers therefore the typical topics of the strain gauge technology applied to composites with particular reference to the compensation of thermal output, the measurement of the coefficients of thermal expansion, the determination of the strain and stress state, the influence of the misalignment error, the reinforcement effect, the determination of the stress intensification factor, the analysis of r…

Trapping Amorphous Intermediates of Carbonates – A Combined Total Scattering and NMR Study

2018

Crystallization via metastable phases plays an important role in chemical manufacturing, biomineralization, and protein crystallization, but the kinetic pathways leading from metastable phases to the stable crystalline modifications are not well understood. In particular, the fast crystallization of amorphous intermediates makes a detailed characterization challenging. To circumvent this problem, we devised a system that allows trapping and stabilizing the amorphous intermediates of representative carbonates (calcium, strontium, barium, manganese, and cadmium). The long-term stabilization of these transient species enabled a detailed investigation of their composition, structure, and morpho…

Effect of proanthocyanidin mediated immediate and delayed dentin sealing on the strength of premolars restored with composite resin inlay.

2019

Background Immediate dentin sealing (IDS) with proanthocyanidin (PA) could be used before cementation with a self-adhesive (SA) cement. The aim of this study was to assess the effect of PA treatment on acid-etched dentin before adhesive application, in IDS and delayed dentin sealing (DDS), on the strengthening property of SA-cemented composite resin inlay in premolars. Material and Methods Eighty-four maxillary premolars were divided into 7 groups (n=12): 1) (Intact) Sound teeth served as controls; groups 2-7) After cavity preparation and fabrication of composite resin inlay, temporary inlays were made and cemented. After one week, the inlays were removed and composite inlays were luted wit…

Effect of composite/amalgam thickness on fracture resistance of maxillary premolar teeth, restored with combined amalgam-composite restorations

2016

Background: Combined amalgam-composite restorations have been used through many years to benefit from the advantages of both dental amalgam and composite resin. Two variations have been mentioned for this technique, this study investigated the fracture resistance of maxillary premolar teeth with extended mesio-occluso-distal (MOD) cavities, restored with the two variations of combined amalgam-composite restorations. Material and Methods: Sixty intact extracted premolar teeth were randomly divided into 6 groups (G1-G6) of 10 teeth. G1; consisted of intact teeth and G2; consisted of teeth with MOD preparations were assigned as the positive and negative control groups respectively. Other exper…