Cyclodextrin-assisted capillary electrophoresis for determination of the cyclic nitramine explosives RDX,HMX and CL-20 comparison with high-performance liquid chromatography

A sulfobutyl ether-beta-cyclodextrin-assisted electrokinetic chromatographic method was developed to rapidly resolve and detect the cyclic nitramine explosives 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaaza-isowurtzitane (CL-20), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and their related degradation intermediates in environmental samples. Development of the electrophoretic method required the measurement of the aqueous solubility of CL-20 which was determined to be 3.59 +/- 0.74 mg/l at 25 degrees C (95% confidence interval, n=3). The performance of the method was then compared to results obtained from existing high-performance liquid chromatography methods including US Environmental Protection Agency method 8330.     

A comparison of the extraction of clove buds with supercritical carbon dioxide and superheated water

Supercritical carbon dioxide and superheated water (subcritical water above 100 °C under pressure) have both been used to extract the buds of cloves (Syzygium aromaticum). The yields of eugenol and eugenyl acetate obtained by these methods and also by steam distillation and liquid solvent (Soxhlet) extraction are similar, but the yields of caryophyllene were lower for the methods using water. Received: 23 December 1998 / Revised: 26 March 1999 / Accepted: 31 March 1999     

Local properties of geodesics onp-convex sets

Summary We prove some local properties of geodesics on p-convex sets. First of all, we give an intrinsic characterization of geodesic in terms of local minimality for the energy functional. Then, we prove local uniqueness and continuous dependence from extrema for geodesics with assigned endpoints. Further, we show a consequence of these results.     

Using several advertising media in a homogeneous market

We propose a variety of models to represent the joint effect of several advertising media on the demand for a product in a homogeneous market, and discuss the associated profit maximization problems. An advertising productivity function represents the combination of several media and, together with demand and advertising cost functions, determines the features of the associated profit problem. We distinguish between additive and nonadditive advertising productivity functions, then between smooth and nonsmooth ones. The demand function may either be linear or not. We observe how different models may exhibit either synergy or interference effects. In some cases we obtain explicit optimal solutions.     

Almost Exponential Maps and Integrability Results for a Class of Horizontally Regular Vector Fields

We consider a family ${\mathcal{H}}:= \{X_1, \dots, X_m\}$ of C ¹ vector fields in ? ⁿ and we discuss the associated ${\mathcal{H}}$ -orbits. Namely, we assume that our vector fields belong to a horizontal regularity class and we require that a suitable s-involutivity assumption holds. Then we show that any ${\mathcal{H}}$ -orbit ${\mathcal{O}}$ is a C ¹ immersed submanifold and it is an integral submanifold of the distribution generated by the family of all commutators up to length s. Our main tool is a class of almost exponential maps of which we discuss carefully some precise first order expansions.     

Local {W^{2,m(\cdot)}_{loc}}regularity for p(.)-Laplace equations

We study ${W^{2,m(\cdot)}_{loc}}$ regularity for local weak solutions of p(·)-Laplace equations where ${p\in C^1(\Omega) \cap C(\overline{\Omega})}$ and ${\min_{x\in \overline{\Omega}} p(x) > 1}$ .     

Lipschitz Continuous Viscosity Solutions for a Class of Fully Nonlinear Equations on Lie Groups

In this paper, we prove existence and uniqueness of Lipschitz continuous viscosity solutions for Dirichlet problems involving a class a fully non-linear operators on Lie groups. In particular, we consider the elementary symmetric functions of the eigenvalues of the Hessian built with left-invariant vector fields.     

Diffusion of iron in lithium niobate: a secondary ion mass spectrometry study

Iron-doped X-cut lithium niobate crystals were prepared by means of thermal diffusion from thin film varying in a systematic way the process parameters such as temperature and diffusion duration. Secondary Ion Mass Spectrometry was exploited to characterize the iron in-depth profiles. The evolution of the composition of the Fe thin film in the range between 600°C and 800°C was studied, and the diffusion coefficient at different temperatures in the range between 900°C and 1050°C and the activation energy of the diffusion process were estimated.     

Synthesis of tetrasubstituted 4,4'-biimidazoles

Highly substituted 4,4'-biimidazoles were synthesized, in good to excellent yields, through a multicomponent imidazole ring synthesis by using imidazol-4-yl-ethane-1,2-diones as starting materials. The obtained compounds were preliminarily tested as chromogenic and fluorescent sensors for heavy metals.