Effect of rotation in generalized thermoelastic solid under the influence of gravity with an overlying infinite thermoelastic fluid

The present problem is concerned with the study of deformation of a rotating generalized thermoelastic solid with an overlying infinite thermoelastic fluid due to different forces acting along the interface under the influence of gravity.The components of displacement,force stress,and temperature distribution are first obtained in Laplace and Fourier domains by applying integral transforms,and then obtained in the physical domain by applying a numerical inversion method.Some particular cases are also discussed in the context of the problem.The results are also presented graphically to show the effect of rotation and gravity in the medium.     

具有立方对称性及两个弛豫时间的微极热弹性介质中调和时间源引起的变形

研究了具有立方对称性及两个弛豫时间的微极热弹性介质在调和时间源中的响应．采用了Fourier变换以及数值逆变换技术．在物理域中,得到了位移、应力、微转动和温度分布的数值结果．将微极立方晶体法向位移、法向力应力、切向耦合应力和温度分布的计算结果,与微极各向同性固体的结果进行比较．绘制了指定材料的数值结果图形．还推断了某些特殊情况的结果．     

Low-Temperature,Ambient Pressure Oxidation of Methane to Methanol Over Every Tri-Iron Node in a Metal–Organic Framework Material

In contrast with metal-modified zeolites, metal–organic framework materials (MOFs) provide a platform that may be significantly more amenable to creating catalysts in which every metal site is endowed with the same coordination environment, and hence, catalytic function. Using MIL-100(Fe) as a prototype, we present the first example of a synthetic heterogeneous catalyst comprised exclusively of active tri-iron moieties participating in the low-temperature oxidation of methane to methanol; in contrast with prior reports on iron-MOFs, we report the near-exclusive formation of methanol at low temperatures and sub-ambient methane pressures, and evidence its effectuation solely by Fe²⁺ sites. The study captures the utility of exploring classes of materials endowed with a high level of definition in structure and catalytic function for the purposes of overcoming persistent scientific and technological challenges in the field of synthetic heterogeneous catalysis.     

Recent Development of Active Ingredients in Mouthwashes and Toothpastes for Periodontal Diseases

Periodontal diseases like gingivitis and periodontitis are primarily caused by dental plaque. Several antiplaque and anti-microbial agents have been successfully incorporated into toothpastes and mouthwashes to control plaque biofilms and to prevent and treat gingivitis and periodontitis. The aim of this article was to review recent developments in the antiplaque, anti-gingivitis, and anti-periodontitis properties of some common compounds in toothpastes and mouthwashes by evaluating basic and clinical studies, especially the ones published in the past five years. The common active ingredients in toothpastes and mouthwashes included in this review are chlorhexidine, cetylpyridinium chloride, sodium fluoride, stannous fluoride, stannous chloride, zinc oxide, zinc chloride, and two herbs—licorice and curcumin. We believe this comprehensive review will provide useful up-to-date information for dental care professionals and the general public regarding the major oral care products on the market that are in daily use.     

Formation of phosphonates and pyrophosphates in the reactions of chlorophosphate esters with strong organic bases

The compounds S(6-t-Bu-4-Me-C₆H₂O)₂P(O)Cl (1), CH₂(6-t-Bu-4-Me-C₆H₂O)₂P(O)Cl (2) and (2,2′-C₂₀H₁₂O₂)P(O)Cl (3) react with diazabicycloundecene (DBU) to give rise to, predominantly, the phosphonate compounds [S(6-t-Bu-4-Me-C₆H₆O)₂P(O)(DBU)]⁺[Cl]⁻ (4), [CH₂(6-t-Bu-4-Me-C₆H₂O)₂P(O) (DBU)]⁺[Cl]⁻ (5) and [(2,2′-C₂₀Hi₂O₂)P(0)(DBU)]⁺[Cl]^- (6). The first two compounds could be isolated in the pure state. In analogous reactions of 1 and 2 with diazabicyclononene (DBN) or N-methyl imidazole, only the pyrophosphates [S(6-t-Bu-4-Me-C₆H₂O)₂P(O)]₂O (7) and [CH₂(6-t-Bu-4-Me-C₆H₂O)₂P(O)]₂O (8) could be isolated, although the reaction mixture showed several other compounds in the phosphorus NMR. A possible pathway for the formation of phosphonate salts is proposed. The X-ray crystal structures of4,7 and8 are also discussed.     

Co-catalysis by transition metal ions in the hydrogen ion catalysed oxidation of iodide ions. A kinetic study

The reaction between KI and [Fe(CN)₆]^3– ion, catalysed by hydrogen ions, was found to be catalysed further by PdCl₂. Separate reactions under similar conditions, studied in the absence as well as in the presence of PdCl₂ catalyst, were found to follow first order kinetics w.r. to [Fe(CN)₆]^3– and [H⁺], while the order was two w.r. to [I^–]. [Fe(CN)₆]^4– ions were found to have a negative effect while changes in ionic strength of the medium do not effect the reaction velocity. Reaction in the presence of PdCl₂ showed direct proportionality w.r. to [PdCl₂]. The rate and extent of the reaction, which takes place even at zero [PdCl₂] in the co-catalysed reaction, was calculated and was found to be in accordance with the rate values of the separately studied reaction at similar concentrations without adding PdCl₂.     

Characterisation and nonisothermal decomposition of cobalt(II) soaps

Summary Cobalt(II) soaps of general formula, Co(O₂CR)₂ (where R= C₁₁H₂₃ and C₁₇H₃₃) have been analysed by elemental analysis and i.r. spectra. Nonisothermal decomposition of these soaps has been studied by t.g.a. The activation energy, E, frequency factor, Z, entropy, S, and free energy, G, are calculated and a probable mechanism for decomposition is proposed.     

Probabilistic and thermodynamic approach on phase behavior of nematic liquid crystals: A comparative study

The systems chosen for the present investigation, p-n-alkylbenzoic acid (nBAC; n = 6, 7) exhibits nematic-isotropic transition. A comparative study based on quantum probabilistic and statistical thermodynamics has been carried out with respect to translational and orientational motions. The evaluation of net atomic charges and dipole moment at each atomic centre has been carried out through the complete neglect differential overlap (CNDO/2) method. The modified Rayleigh-Schrodinger perturbation theory along with multicentered-multipole expansion method has been employed to evaluate the long-range intermolecular interactions, while the ‘6-exp’ potential function has been assumed for short-range interactions. The total interaction energy values obtained through these computations have been used as input to calculate the probability of occurrence of a particular configuration using the Maxwell-Boltzmann formula. Further, thermodynamic parameters such as Helmholtz free energy, and entropy at room temperature (300 K), and nematic-isotropic transition temperatures have been computed. An attempt has been made to understand the structure-phase behaviour relationship at molecular level.     

Normal- and Reversed-Phase Thin-Layer Chromatography of Three Structurally Related Organophosphorus Pesticides of Forensic Importance

JPC – Journal of Planar Chromatography – Modern TLC - Recently, considerable numbers of poisoning cases have been reported owing to the ingestion of three structurally related...