The proteolytic activity of selected lactic acid bacteria in fermenting cow's and camel's milk and the resultant sensory characteristics of the products

The aim of this study was to evaluate the proteolytic activities of 14 strains of lactic acid bacteria and their impact on sensory characteristics of the resultant fermented cow and camel milk. The results showed that Lactobacillus rhamnosus PTCC 1637 and Lactobacillus fermentum PTCC 1638 had high protease activity and high mean values for sensory quality in fermented cow's and camel's milk. Lactobacillus plantarum PTCC 1058 revealed high protease activity and sensory scores in camel milk. Consequently, milk fermentation using such strains might be recommended for the development of dairy products containing bioactive peptides.     

Rapid synthesis of flower-like ZnO nanostructures

Flower-like ZnO nanostructures were prepared via microwave assisted heating in the presence and absence of ionic liquid (IL). X-ray diffraction analysis (XRD), Scanning electron microscopy SEM and room temperature photoluminescence (PL) spectra have been employed for characterization of the products. The SEM image illustrates the surface of flower-like ZnO prepared in the presence of IL is not smooth and consists of nanoparticles with grain size of about 48 nm. PL spectra of flower-like ZnO in absence and presence IL reveal similar photoluminescence features: a strong UV, weak blue and green-yellow emissions peak at a bout 393 nm, 448 nm and 583 nm respectively. The strong UV photoluminescence and the weak green emission indicate the good crystallization quality of the flower-like nanostructure. The results show that imidazolium-based IL can be used as template for achieving very high level control over the size and shape of nanostructures. The approach developed in this work can potentially be used as a viable method for making various other uniform nanostructures in the presence of IL. This method is simple, fast, low-cost and suitable for large-scale production of ZnO nanostructures.     

Effect of tectonics and earthquakes on geothermal activity near plate boundaries: A case study from South Iceland

We studied fracture-controlled geothermal fields in the Hreppar Rift-Jump Block (HRJB), a micro-plate bounded by two NNE rifts and the E–W transform zone of the South Iceland Seismic Zone (SISZ). Distinguishing whether the extensional rift swarm or the transform zone shear fractures host the geothermal activity is challenging. GPS mapping of 208 springs and tectonic analysis indicate that six Riedel shear fracture sets of an older transform zone in the HRJB are permeable. Northerly dextral strike-slip faults are the principal permeable faults, although the highest discharge and temperature are found at their intersections with other fracture sets. Two northerly faults from the HRJB connect to the source faults of the major 1784 and 1896 earthquakes within the active SISZ. The 1784 earthquake caused pressure changes as far north as the studied springs, indicating that earthquakes keep faults permeable over hundreds of years.     

A stochastic games framework for verification and control of discrete time stochastic hybrid systems

We describe a framework for analyzing probabilistic reachability and safety problems for discrete time stochastic hybrid systems within a dynamic games setting. In particular, we consider finite horizon zero-sum stochastic games in which a control has the objective of reaching a target set while avoiding an unsafe set in the hybrid state space, and a rational adversary has the opposing objective. We derive an algorithm for computing the maximal probability of achieving the control objective, subject to the worst-case adversary behavior. From this algorithm, sufficient conditions of optimality are also derived for the synthesis of optimal control policies and worst-case disturbance strategies. These results are then specialized to the safety problem, in which the control objective is to remain within a safe set. We illustrate our modeling framework and computational approach using both a tutorial example with jump Markov dynamics and a practical application in the domain of air traffic management.     

Numerical solution of GRLW equation using Sinc-collocation method

In this paper, we present a meshfree technique for the numerical solution of the generalized regularized long wave (GRLW) equation. This approach is based on a global collocation method using Sinc basis functions. The propagation of single solitons and the interaction of two solitary waves are used to validate the method which is found to be accurate and efficient. The three invariants of the motion are evaluated to determine the conservation properties of the method.     

Fault-tolerant computation of distributed regular path queries

Regular path queries are the building blocks of almost any mechanism for querying semistructured data. Despite the fact that the main applications of such data are distributed, there are only few works dealing with distributed evaluation of regular path queries. In this paper we present a message-efficient and truly distributed algorithm for computing the answer to regular path queries in a multi-source semistructured database setting. Our algorithm is general as it works for the larger class of weighted regular path queries on weighted semistructured databases.     

Simulations of DNA Computing with In Vitro Selection

An attractive feature of DNA-based computers is the large number of possible sequences (4 ⁿ ) of a given length n with which to represent information. The problem, however, is that any given sequence is not necessarily independent of the other sequences, and thus, reactions among them can interfere with the reliability and efficiency of the computation. Independent sequences might be manufactured in the test tube using evolutionary methods. To this end, an in vitro selection has been developed that selects maximally mismatched DNA sequences. In order to understand the behavior of the protocol, a computer simulation of the protocol was done, results of which showed that Watson-Crick pairs of independent oligonucleotides were preferentially selected. In addition, to explore the computational capability of the selection protocol, a design is presented that generates the Fibonacci sequence of numbers.     

A method for data-driven evaluation of operator impact on energy efficiency of digging machines

Material handling (including digging) is one of the most energy-intensive processes in mining. Operators’ skills and practices are known to be some of the major factors that affect energy efficiency of digging operations. Improving operators’ skills through training is an inexpensive and effective method to improve energy efficiency. The method proposed in this work uses data collected by monitoring systems on digging equipment to detect the monitored parameters that lead to differences in energy efficiency of operators (responsible parameters). After data extraction, removing the outliers, and identifying the operators with sufficient working hours, correlation analysis can be used to find parameters that are correlated with energy efficiency. Regression analysis on pairs of operators is then used to detect responsible parameters. Random sampling is used to overcome missing data issues in the analysis. This statistics-based method is simple and adequately accounts for the high variability in data collected from these monitoring systems. The proposed method was illustrated using data collected on five operators working on a 64-m³ (85 yd³) Bucyrus-Erie 1570w dragline. The case study results show that dump height and engagement/disengagement position of the bucket are the most likely parameters to cause differences between energy efficiency of these operators. On the other hand, cycle time, payload, and swing in time are least likely to influence differences in operator energy efficiency.     

Study of hexavalent chromium ion adsorption on nano-porous anodic aluminum oxide

The present study evaluates adsorption of hexavalent chromium ion (Cr(VI)) from contaminated solution on nano-porous anodic aluminum oxide (AAO). The AAO sorbent was characterized by field emission scanning electron microscope (FE-SEM) and Fourier transform infrared (FTIR) spectroscope. Effects of the solution pH, contact time, and AAO quantity on Cr(VI) adsorption were investigated. It was shown that Cr(VI) adsorption on AAO was strongly pH dependent and Cr(VI) removal increased by decreasing of the pH, Cr(VI) displays anion-type sorption behavior on the AAO sorbent. Chromium ion removal of 82% was obtained at presence of 0.05 g/L AAO, pH of 1, and contact time of 40 min in the solution.