A homotopy continuation method for solving normal equations

In this paper, we present a continuation method for solving normal equations generated byC ² functions and polyhedral convex sets. We embed the normal map into a homotopyH, and study the existence and characteristics of curves inH ¹(0) starting at a specificd point. We prove the convergence of such curves to a solution of the normal equation under some conditions on the polyhedral convex setC and the functionf. We prove that the curve will have finite are length if the normal map, associated with the derivative df(·) and the critical coneK, is coherently oriented at each zero of the normal mapf _c inside a certain ball of ⁿ . © 1998 The Mathematical Programming Society, Inc. Published by Elsevier Science B.V.This research was performed at the Department of Industrial Engineering, University of Wisconsin-Madison, Madison, WI, USA.     

One-step Synthesis of PCL-Urethane Networks using a Crosslinking/de-crosslinking Agent

Thermally reversible cross-linked polycaprolactone-urethane (PCL-U) was prepared in one-step procedure. The PCL-U networks were synthesized from a di-isocyanate (4,4′-methylene bis(cyclohexylisocyanate) (HMDI) and hydroxyl bearing macromers and monomers: hydroxy-terminated PCL, glycerol and a di-alcohol Diels-Alder (DA) adduct. This adduct was used to introduce both diene and dienophile functions in the structure and also to protect the maleimide functions from polymerization. The thermoresponsive behavior of the material was characterized by commonly used methods such as solubility tests at different temperatures and differential scanning calorimetry analyses to highlight rDA reactions and also by rheological analysis. The effects of the cooling rate, the molar mass of polycaprolactone as well as the molar ratio [di-Isocyanate]/[PCL-diol] on the cross-linking/de-cross-linking temperatures were also analyzed. The reversible networks obtained have a self-healing behavior.     

Experimental and theoretical cooling velocity profile inside laser welded metals using keyhole approximation and Boubaker polynomials expansion

In this paper we are concerned with the t-dependent cooling velocity during laser welding sequences. The temperature profile has been yielded by using keyhole approximation for the melted zone and solving the heat transfer equation. A polynomial expansion has been adopted as a guide to determining the cooling velocity during welding cut-off stage. A thorough comparison with experimental results and recently published profiles has been carried out.     

Chemical composition and in vitro evaluation of antimicrobial and anti-acetylcholinesterase properties of the flower oil of Ferula lutea

The present work describes the chemical composition and evaluates the antimicrobial and the anti-acetylcholinesterase properties of the flower oil from the Tunisian Ferula lutea obtained by hydrodistillation and analyzed by combination of GC/FID and GC/MS. The chemical composition of the flower oil of this species is reported for the first time. Seventeen compounds were identified accounting for 94.3% of the total oil. The chemical composition of this essential oil was characterized by a high proportion of monoterpene hydrocarbons (80.4%) among which delta-3-carene (31.2%) and alpha-pinene (25.8%) were the predominant compounds. The oxygenated monoterpenes represent the second major fraction (12.0%), 2,3,6-trimethylbenzaldehyde (10.9%) being the predominant one. Furthermore, the isolated oil was tested for its antimicrobial activity using the disc-diffusion and the microdilution assays against six Gram-positive and five Gram-negative bacteria as well as towards eight Candida species. It was found that flower oil of F. lutea exhibited interesting antibacterial and anticandidal activity (MIC = 39 mcirog/mL against Escherichia coli, Staphylococcus aureus and S. epidermidis and MIC = 156 microg/mL against Candida albicans). The anti-acetylcholinesterase effect of this oil was also evaluated in this work. Results showed that this oil exhibits significant activity (IC50 =70.25 +/- 5.41 microg/mL).     

Development and characterisation of glass and glass ceramic sealants for solid oxide electrolyser cells

Glass and glass ceramic are now well known for their high performances as sealants operating around 800 °C in solid oxide electrolyser cell. Several new formulations have been prepared and investigated: silica alkali borosilicate glass formulations that will create a glass sealant and calcium aluminosilicate formulations that will create a glass ceramic sealant. Thermal and physicochemical properties of several glasses and glass ceramics along with the crystallisation behaviour were investigated. The glass transition temperatures (T _g) of the prepared glasses were found to be within the range of 600–730 °C. Shrinkage, sintering, softening, deformation and crystallisation temperatures of the parent glasses have been measured by hot stage microscopy. Microstructure and chemical composition of crystalline phases have been investigated using microprobe analysis. Bonding characteristics as well as chemical interactions of the parent glasses with yttria-stabilised zirconia (YSZ®) electrolyte and high chromium steel-based interconnect (Crofer®) have also been studied.     

Evaluation of the Anaerobic Co-Digestion of Sewage Sludge and Tomato Waste at Mesophilic Temperature

Sewage sludge is a hazardous waste, which must be managed adequately. Mesophilic anaerobic digestion is a widely employed treatment for sewage sludge involving several disadvantages such as low methane yield, poor biodegradability, and nutrient imbalance. Tomato waste was proposed as an easily biodegradable co-substrate to increase the viability of the process in a centralized system. The mixture proportion of sewage sludge and tomato waste evaluated was 95:5 (wet weight), respectively. The stability was maintained within correct parameters in an organic loading rate from 0.4 to 2.2 kg total volatile solids (VS)/m³ day. Moreover, the methane yield coefficient was 159 l/kg VS (0 °C, 1 atm), and the studied mixture showed a high anaerobic biodegradability of 95 % (in VS). Although the ammonia concentration increased until 1,864?±?23 mg/l, no inhibition phenomenon was determined in the stability variables, methane yield, or kinetics parameters studied.     

Existence of solutions for a perturbation sublinear elliptic equation in {\mathbb {R}^N}

In this paper we consider the following problem $\left\{\begin{array}{l} -\Delta u=u-\left|u\right|^{-2\theta}u+f \\u \in H^1(\mathbb{R}^N)\cap L^{2(1-\theta)}(\mathbb{R}^N)\end{array}\right.$ ${f \in L^2(\mathbb{R}^N)\cap L^\frac{2(1-\theta)}{1-2\theta}(\mathbb{R}^N),\, N\geq 3,\, f\geq 0,\, f \neq 0}In this paper we consider the following problem

{l -Du=u-|u|-2qu+f u ? H1(\mathbbRN)?L2(1-q)(\mathbbRN)\left\{\begin{array}{l} -\Delta u=u-\left|u\right|^{-2\theta}u+f \\u \in H^1(\mathbb{R}^N)\cap L^{2(1-\theta)}(\mathbb{R}^N)\end{array}\right.      60. Synthesis of New Phosphonate Derivatives of Naphtho[2,1-b[Pyran]3,2-e][1,2,4]Triazolo [1,5-c]Pyrimidines      Anis Romdhane  Jean-François Gallard  M’hamed Ali Hamza  Hichem Ben Jannet 《Phosphorus, sulfur, and silicon and the related elements》2013,188(5):612-618 Abstract The synthesis of new naphthopyranotriazolopyrimidines phosphonates 4a–i in good yields (74%–93%) has been accomplished via Michaelis–Arbusov rearrangement by the reaction of trialkyl phosphite with naphthopyranotriazolopyrimidines chloride 3a–e, which were obtained from α-functionalized iminoethers 1 in two steps. The synthesized compounds 4a–i were completely characterized by IR, 1H, 13C, and 31P NMR and HRMS. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.      [首页] « 上一页 [1] [2] [3] [4] [5] 6 [7] [8] [9] [10] [11] 下一页 » 末  页»

Synthesis of New Phosphonate Derivatives of Naphtho[2,1-b[Pyran]3,2-e][1,2,4]Triazolo [1,5-c]Pyrimidines

Abstract

The synthesis of new naphthopyranotriazolopyrimidines phosphonates 4a–i in good yields (74%–93%) has been accomplished via Michaelis–Arbusov rearrangement by the reaction of trialkyl phosphite with naphthopyranotriazolopyrimidines chloride 3a–e, which were obtained from α-functionalized iminoethers 1 in two steps. The synthesized compounds 4a–i were completely characterized by IR, ¹H, ¹³C, and ³¹P NMR and HRMS.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.