Some Analytical Solutions for Groundwater Flow and Transport Equation

This paper presents the use of symmetry reduction method resulting in new exact solutions for the groundwater flow and transport equation. It is assumed that the radionuclides are transported by advection-diffusion in a single fracture and diffusion in the surrounding rock-matrix. The application of one-parameter group reduces the number of independent variables, and consequently the governing PDE of (1+2)-dimension reduces to set of ODEs which are solved analytically. This enables us to present some new exact time-dependent solutions of the advection-diffusion equation.     

Decoration of electrospun polyacrylonitrile nanofibers with ZnO nanoparticles and their application for removal of Pb ions from waste water

The adsorption behavior of lead (II) from aqueous solutions utilizing ZnO/polyacrylonitrile (PAN) nanofibers was studied. ZnO/PAN nanofibers were prepared by electrospinning method. The changes of the parameters of adsorbent amount, pH, contact time, and temperature were tested in the adsorption experiments. The adsorption was well described by the Langmuir adsorption isotherm model. The thermodynamic parameters indicate that the adsorption process is exothermic. The dynamic behavior of the lead (II) ions adsorption by PAN/ZnO nanofibers was well described by the pseudo-second-order kinetic model. The adsorbent can be regenerated by suitable desorption processes for multiple uses without significant loss of its adsorption capacity.     

Optimization of an HPLC method for determination of gabapentin in dosage forms through derivatization with 1-fluoro-2,4-dinitrobenzene

A rapid, sensitive and accurate high performance liquid chromatography with UV detection method was developed and validated for the quantification of gabapentin in dosage forms. Gabapentin was quantified after pre-column derivatization with 1-fluoro-2,4-dinitrobenzene. Amlodipine was used as an internal standard. The chromatographic separation was carried out on a Nova-Pak C(18) column using a mixture of acetonitrile-sodium dihydrogenphosphate (pH 2.5; 0.05 M) (70:30, v/v) as mobile phase with UV detection at 360 nm. The method was linear over the range of 10-500 microg/ml of gabapentin (r(2)>0.999). The within-day and between-day precision values were in the range of 0.86-1.11%. The method was successfully used for quantitative determination and dissolution rate study of Neurontin capsules.     

Application of ZnO‐Al2O3 Nanocomposite as Nanocatalyst for Photodegradation of Acid Violet 5B

ZnO‐Al₂O₃ nanocomposite (ZANC) is used as nanocatalyst for photodegradation of acid violet 5B (AV5B) as an industrial dye. The experimental data shows that the degradation of AV5B is accelerated by ZANC and UV light. The effects of various parameters such as pH, hydrogen peroxide and ethanol are investigated on the photodegradation efficiency. Photocatalytic degradation rate of AV5B is increased by ethanol and hydrogen peroxide. Based on the kinetic studies, the rate constant of the photodegradation reaction is estimated 2.829 × 10^‐1 min^‐1.     

A rewarding-punishing coordination mechanism based on Trust in a divergent supply chain

Coordination of decentralized supply chains using contract design is a problem that has been widely addressed in the literature. We consider a divergent supply chain including a supplier and several retailers producing fashion products with short sale seasons. The retailers cooperate with the supplier as sales agents; i.e., they work in the framework of revenue sharing contracts. Because of their proximity to the market, retailers can provide more accurate demand forecasts to the supplier that is used to decide on issues such as capacity building and market prices with regard to retailers stiff due dates, different lead times and different price-dependent demand functions. To ensure abundant supply and cope with the demand variability, the retailers have an incentive to exaggerate their private forecast information. In this study, we propose a new rewarding-punishing coordination mechanism based on trust between supply chain tiers, considered as a differentiation factor between honest and deceptive partners. An optimization model is developed as a building block of this mechanism. An approximation method is used to simplify and solve the problem. The model is then implemented using Monte-Carlo simulation in four different situations, according to 10 different strategies for forecast information sharing. The findings from the tests show that the mechanism including trust as a decisional factor performs better than ‘No Trust’ mechanism in all situations. These results suggest that taking into account Trust in designing coordination mechanism may have significant influence on the financial performance of the supply chain.     

Study on the effect of laser parameters on wakefield excitation in femtosecond pulsed laser–plasma interaction using PIC method

Propagation of an intense short laser pulse through under-dense plasma can produce huge amplitude plasma wake field. A 3D particle in cell (PIC) method was used to simulate the wakefield generation for different laser parameters such as intensity, pulse duration, spot size and temporal pulse shape. Our study shows that the amplitude of wakefield is increased with laser intensity, but it is decreased with spot size. The results for pulse shape and pulse duration depend on their optimum values.     

Uniform copper nanoparticles as an inexpensive and efficient catalyst for synthesis of novel β-carbonyl-1, 2, 3-triazoles in water medium

Copper nanoparticles as an efficient, inexpensive catalyst were prepared via ball milling for synthesis of β-carbonyl 1, 2, 3-triazoles from azido alcohol by click reaction in water. An extensive range of raw materials such as sodium azide, phenacyl bromide, epichlorohydrin, and terminal alkynes were used. Complete reduction of CuO in presence of NaBH₄ was done via ball milling with a ball-to-powder weight ratio of 50:1 under air atmosphere at room temperature. The final copper nanoparticles (Cu NPs) were characterized by SEM, EDX, XRD and FT-IR. The Cu NPs catalyzed one-pot three component synthesis of β-carbonyl 1, 2, 3-triazoles at room temperature with short reaction time and high product yields. The catalyst could be easily recovered and reused in several successive runs.

     

Metallat‐Ionen [Al(OR)4]— als Chelatliganden für Übergangsmetall‐Kationen

Metalat Ions [Al(OR)₄]^— as Chelating Ligands for Transition Metal Cations Waterfree CoCl₂ can be reacted with [{Li(Diglyme)}{Al(O^tBu)₄}] in THF to the complex [Li(THF)₄][{CoCl₂}{Al(O^tBu)₄}]. Addition of diglyme to the reaction mixtures gives the blue compound [Li(diglyme)₂][{CoCl₂}{Al(O^tBu)₄}] ( 1 ). According to this procedure the Fe^II complex [Li(Diglyme)₂][{FeCl₂}₂{Al(O^tBu)₄}] ( 2 ) was formed by treatment of FeCl₂ with Li[Al(O^tBu)₄]. [{Li(diglyme)}{Al(O^tBu)₄}] in THF/diglyme can be used as alkoxide transfer reagent on TiCl₄ to give the neutral complex [TiCl₂(O^tBu)₂(diglyme)] ( 3 ). The sky‐blue salt [Li(THF)₄]₂[{CoCl₂}₃{Al(OCH₂Ph)₄}₂] ( 4 ) was obtained by reaction of Li[Al(OCH₂Ph)₄] with CoCl₂ in THF. By treatment of 4 with diglyme ligand redistribution was observed giving the sky‐blue compound [Li(Diglyme)₂]₂[{CoCl₂}₃{Al(OCH₂Ph)₄}₂] ( 5 ) and the violet salt [Li(Diglyme)₂]₂[Co₂Cl₅(OCH₂Ph)] ( 6 ). A similar salt can be synthesized also directly from Li[Al(O^tBu)₄] and CoCl₂ in diglyme to give [Li(Diglyme)₂]₂[Co₂Cl₅(O^tBu)] ( 7 ). 1 — 7 were characterized by IR spectroscopy, partly by mass spectrometry and X‐ray analyses. UV‐VIS spectra were recorded from 1 and 5 . According to the X‐ray analyses the M^II ions as well as the Al^III ions are coordinated distorted tedrahedrally. In 1 , 2 , 4 und 5 the unit [Al(OR)₄]^— acts a chelating ligand as desired.     

Morpholin als ambidenter Ligand

Morpholine as Ambident Ligand The reaction of MeInCl₂ with Li‐morpholinate [Li(Morph)] at 20 °C in THF gave after work‐up and recrystallization from diglyme the salt [Li(Diglyme){In₃Me₂Cl₄(Morph)₄}]·Diglyme ( 1 ). The treatment of the reaction mixture of MesInCl₂/Li(Morph) with wet THF yield as only isolated compound the coordination polymer [Li₆Cl₆(HMorph)₃] ( 2 ). Under similar conditions the reaction of InCl₃ with Li(Morph) led after work‐up in wet THF to [Li(Diglyme)₂][InCl₄(HMorph)₂] ( 3 ). 1 – 3 were characterized by NMR and IR spectroscopy as well as by X‐ray analysis. According to this, 1 contains the trinuclear anion [In₃Me₂Cl₄(Morph)₄]^? in which one of the morpholinate ligands is coordinated via N atom to the In³⁺ ions, while the O atom belongs to the coordination sphere of the Li⁺ ion. In 2 , LiCl forms a hexagonal heteroprismn, in which the morpholine molecules are responsible for a 3d network via coordination of both Lewis‐basic heteroatoms. 3 contains trans‐[InCl₄(Hmorph)₂]^? ions, connected by hydrogen bonding along [011].     

β‐Aminoacrolein: An ab initio,AIM and NBO study

The molecular structure and the intramolecular hydrogen bonding of β‐aminoacrolein and its simple derivatives were investigated at the MP2 and B3LYP levels of theory using the standard 6‐311++G(d, p) basis set. The “atoms in molecules” or AIM theory of Bader which is based on topological properties of the electron density (ρ), was used. Additionally, an analysis of the critical points was performed to study the nature hydrogen bonding in these systems. Natural bond orbital (NBO) analysis was also carried out for to better comprehend the nature of the intramolecular interactions in β‐aminoacrolein and its derivatives. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008