Application of Organic Acid Based Artificial Neural Network Modeling for Assessment of Commercial Vinegar Authenticity

Food Analytical Methods - Vinegar as a nutraceutical substance is classified to various types related to the different substances applied in production process. Therefore, identity of the source...     

On the stabilization mechanism of Doogh (Iranian yoghurt drink) by gum tragacanth

Serum separation in Doogh, a favorite acidic dairy drink in the Middle East, is a major problem which happens due to low pH (≤4.00) and aggregation of caseins. Therefore, in the present study the influence of gum tragacanth (GT) and its soluble and insoluble fractions on prevention of serum separation as well as stabilization mechanisms were investigated using rheological, zeta potential and microscopic measurements. According to our findings, the soluble tragacanthin (T) and GT prevented serum separation at concentrations of 0.100 and 0.200%, respectively. Furthermore, the proper rheological model for control was Newtonian whereas for the others it was Power law. Based on viscoelastic experiments, Dooghs containing T and GT exhibited dominant viscose and elastic behaviors, respectively. In addition, the presence of T and GT changed the zeta potential values from positive to negative. It was elucidated that T adsorbs onto casein and induces stabilization via electrostatic and steric repulsions. Moreover, the insoluble bassorin (B) may assist stabilization by increasing the viscosity.     

A statistical investigation of wind characteristics and wind energy potential based on the Weibull and Rayleigh models in Rwanda

A wind energy system converts the kinetic energy of the wind into mechanical or electrical energy that can be harnessed for practical uses and transform the economy of rural areas where access to water and electricity is very restricted and industry is almost nonexistent in most of the developing countries like Rwanda. Assessing wind power potential for a location is an imperative requirement before making a decision for the installation of windmills or a wind electric generator and evaluating plans for relating projects. The aim of the present study was to evaluate the potential of wind resource in Rwanda and to constitute a database for the users of the wind power. A time series of hourly daily measured wind speed and wind direction for the period between 1974 and 1993 on five main Rwandan meteorological stations was provided by the National Meteorology Department. Statistical methods applying Weibull and Rayleigh distribution were presented to evaluate the wind speed characteristics and the wind power potential at a height of 10 m above ground level using hourly monthly average data. Those characteristics were extrapolated for higher levels in altitude. The results give a global picture of the distribution of the wind potential in different locations of Rwanda.     

Sol-gel derived PbTio3-polymer piezoelectric composites

Amorphous lead titanate powder was prepared using a sol-gel process. The powder was fired to temperatures ranging from 500°C to 1200°C and soaked for various lengths of time. X-ray diffraction confirmed that the fired powders were tetragonal PbTiO₃. Surface area measurements indicated that the specific surface area of the powder decreased with increasing heat treatment. The powders were mixed with Eccogel polymer to make composites in which the ceramic phase constituted 60 percent by volume. Piezoelectric coefficients were found to be greatest for those composites containing powder fired to 1100°C and soaked for 1 hour. The d_hg_h value obtained for this heat treatment was 540×10^-15m²N^-1.     

An efficient parallel algorithm for the longest path problem in meshes

The longest path problem is the problem of finding a simple path with the maximum number of vertices in a given graph, and so far it has been solved polynomially only for a few classes of graphs. This problem generalizes the well-known Hamiltonian path problem, hence it is NP-hard in general graphs. In this paper, first we give a sequential linear-time algorithm for the longest path problem in meshes. Then based on this algorithm, we present a constant-time parallel algorithm for the problem, which can be run on every parallel machine.