Steady state analysis of an M/G/1 queue with two phase service and Bernoulli vacation schedule under multiple vacation policy

This paper examines the steady state behaviour of a batch arrival queue with two phases of heterogeneous service along and Bernoulli schedule vacation under multiple vacation policy, where after two successive phases service or first vacation the server may go for further vacations until it finds a new batch of customer in the system. We carry out an extensive stationary analysis of the system, including existence of stationary regime, queue size distribution of idle period process, embedded Markov chain steady state distribution of stationary queue size, busy period distribution along with some system characteristics.     

Correlation of thermodynamic stabilities of charge transfer complexes of anthracene and chloranil with those of tetra-cyanoethylene

The formation constants of charge-transfer complexes of a number of 9- and 9,10-substituted anthracenes with chloranil have been measured by a spectrophotometric method and the corresponding thermodynamic parameters ΔG°_c, ΔH°_c and ΔS°_c evaluated in various solvents. v_max values of the chargetransfer band for chloranil were linearly related to those for tetracyanoethylene (TCNE). Good correlations were also obtained between v_max and the corresponding ionisation potentials Ip of the donor molecules. In addition ΔG°_c varied linearly with Ip and from these correlations, values of ΔG°_c, etc. for the corresponding TCNE complexes could be calculated. These values are otherwise very difficult to obtain due to the high reactivity of TCNE.     

Cupressus sempervirens Essential Oil: Exploring the Antibacterial Multitarget Mechanisms,Chemcomputational Toxicity Prediction,and Safety Assessment in Zebrafish Embryos

Nowadays, increasing interest has recently been given to the exploration of new food preservatives to avoid foodborne outbreaks or food spoilage. Likewise, new compounds that substitute the commonly used synthetic food preservatives are required to restrain the rising problem of microbial resistance. Accordingly, the present study was conducted to examine the chemical composition and the mechanism(s) of action of the Cupressus sempervirens essential oil (CSEO) against Salmonella enterica Typhimuriumand Staphyloccocus aureus. The gas chromatography analysis revealed α-pinene (38.47%) and δ-3-carene (25.14%) are the major components of the CSEO. By using computational methods, such as quantitative structure–activity relationship (QSAR), we revealed that many CSEO components had no toxic effects. Moreover, findings indicated that α-pinene, δ-3-carene and borneol, a minor compound of CSEO, could inhibit the AcrB-TolC and MepR efflux pump activity of S. enterica Typhimurium and S. aureus, respectively. In addition, our molecular docking predictions indicated the high affinity of these three compounds with active sites of bacterial DNA and RNA polymerases, pointing to plausible impairments of the pathogenic bacteria cell replication processes. As well, the safety profile was developed through the zebrafish model. The in vivo toxicological evaluation of (CSEO) exhibited a concentration-dependent manner, with a lethal concentration (LC₅₀) equal to 6.6 µg/mL.     

Influences of nanoparticles and chain length on thermodynamic and electrical behavior of fluorine liquid crystals

Hydrogen-bonded polar nematic liquid crystal series with the general formula nOBAF (n = 7—12) is studied. The mesomorphic characterization is demonstrated through differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The complexes with short alkyl chains (n=7, 8) present a wide nematic range and monotropic smectic F mesophase, whereas the longer alkyl chain (n=10—12) analogues show high melting and low clearing mesomorphic liquid crystals. The thermal range of the mesophase and the birefringence increase with chain length decreasing. Furthermore, the effect of the nanoparticles (LiNbO₃) on the thermal and the electrical behavior of 8OBAF are investigated. The presence of LiNbO₃ nanoparticles increases the conductivity and reduces the resistivity of the complex.     

Access to New Endoperoxide Derivatives by Electrochemical Oxidation of Substituted 3‐Azabicyclo[4.1.0]hept‐4‐enes

A series of substituted 3‐azabicyclo[4.1.0]hept‐4‐ene derivatives were prepared and analysed by cyclic voltammetry. Preparative aerobic electrochemical oxidation reactions were then carried out. Three original endoperoxides were isolated, characterised and subjected to antimalarial and cytotoxicity activity assays.     

Finding weak defining hyperplanes of PPS of the BCC model

Production possibility set (PPS) is intersection of the several halfspaces. Every halfspace corresponds with one strong or weak defining hyperplane (facet). This research proposes a method to find weak defining hyperplanes of PPS of BCC model. We state and prove some properties relative to our method. Numerical examples are provided for illustration.     

Optimal Shape Design for Metal Forming Problems by the Finite Element Method

In this work, a method for calculation of the optimal shapes of axisymmetrical converging dies by the finite element method is presented. The shape optimization problem considered in this paper is to find the best shape of the die such that the flow rate will be uniform at the die exit.The optimization problem is to minimize an objective function by varying a part of boundary (ie: the shape of die) subject to constraints imposed by the metal forming problem. In this method, the B-spline functions allow us to determine the shape of the die, using its control points as design variables. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)