Ice nucleation active (INA) bacteria are common epiphytic inhabitants that cause frost damage in many plants in the near-zero temperatures. Yet, no studies were found in ice nucleation bacteria associated with pistachio trees. In our earlier study some INA strains were identified and reported. These were assigned as Pseudomonas fragi, P. putida, P. moraviensis and Pantoea agglomerans. In current work, two new strains namely P. viridiflava and Entrobacter cloacea were identified. Their ice nucleation frequency were evaluated and compared with above-mentioned ice positive strains isolated from pistachio trees. Pseudomonas fragi raf3 was considered as the most ice nucleation active bacteria. This was followed by P. putida raf6, P. moraviensis raf1, P. moraviensis raf5, Pantoea agglomeranse raf7, P. viridiflava raf2, Entrobacter cloacea raf8 and Pseudomonas sp. raf4, respectively. To detect INA genes, two sets of degenerate primers were used and partial INA gene sequences were amplified. INA gene sequence )425bp) for Pseudomonas putida raf6, Pantoea agglomerans raf7 and P. fragi raf3 were amplified with primer pair of 3308/3463. Whereas, a fragment of 194bp was detected in Pseudomonas sp. raf4, P. moraviensis raf5 and P. moraviensis raf1 using forward and reverse primer pair of 3076/3463. Entrobacter cloacea raf8 has reported for the first time as epiphytic ice plus strain. The capability of the latter as a bacterial biocontrol agent against insect pests was reported.

In this study, considering slippage between a robot end-effector and an object, adaptive control of a one-finger hand manipulating an object is explored. This system is a good sample to develop different techniques such as grasp analysis, grasp synthesis, stability analysis and designing different types of controller for cooperative manipulator systems. Due to the presence of inequality equations in frictional point contact modeling, a novel formulation is developed to replace the equality and inequality equations with a single second order differential equation with switching coefficients. Introducing this new friction contact model, an input-output conventional form is derived using the equality and inequality equations of motion of the system. Using this new form of motion equations, two adaptive controllers with simple update laws are proposed that both of them ensure the asymptotic convergence of the object position tracking as well as slippage control while compensating the system uncertainties. The first controller compensates the uncertain masses of the manipulator links and the object while the second one compensates the uncertain coefficients of friction. Numerical simulation is utilized to evaluate performance of the proposed controllers.

In this paper, steady creeping motion of non-Newtonian falling drop through a viscous fluid is investigated analytically. Here, the Upper Convected Maxwell model (UCM) is used for drop phase and Newtonian model is considered for external fluid. The perturbation technique is used to solve both exterior and interior flows and Deborah number, which indicate the elastic effect is considered as the perturbation parameter. The present solution is derived up to second order of perturbation parameter so this solution has suitable accuracy for drops made from dilute polymeric solutions. It was found that the Newtonian drop has a spherical shape during the creeping motion but the non-Newtonian drop loses this shape and takes an oblate form. By increasing the elastic effect, a dimple at the rear end of the drop is created and developed. Here, it is shown that the present results have better agreement with experimental data than the previous analytical studies. The origin of drop deformation is also considered and it is proved that the elastic property of drop phase creates a concentrated normal stress at the rear end of the drop that causes the dimple shape in this region.

The ice nucleation active (INA+) bacteria are one of the most important biological factors in fields and orchards frost damage. Most of these bacteria usually accelerate the freezing process at-5° C and higher temperatures. In order to identify INA+ bacteria, many plant samples were screened and one positive Ice bacterium associated with onion bulb was selected. The bacterium was then tentatively identified using some key bacteriological methods. Accurate identification of the strain A at species level was made by PCR amplification of 16SrRNA followed by blast at NCBI. Ice nucleation activity of the bacterium was tested by tube INA assay and droplet freezing method. Due to the absence of a nucleus-producing gene for representative isolate at the NCBI site, a primer set similar to INAZ gene of Pseudomonas syringae was designed and PCR analysis was performed. PCR-amplicons were further analyzed by plasmid DNA analysis as well as cloning and sequencing. The results were indicated that there might be different types of ice gene in Bacillus cereus strain A. This is the first report of an Ice-plus Bacillus cereus from plant samples.

The present numerical study investigates the effect of a bluff body on outer wall temperature in micro scale combustor. Combustion of lean premixed hydrogen-air mixture is simulated in two dimensions domain utilizing the detailed chemistry of Li et al. (13 species with 19 chemical reactions) and different mass diffusivity for each species. The effect of bluff body in combustor is studied in two viewpoints: shape of bluff body and number of bluff bodies. Two shapes of bluff body including square and triangular shape are considered to study the combustion efficiency and outer wall temperature. The results illustrate that the shape of bluff body does not have an obvious effect on outer wall temperature so triangular shape outer wall temperature is slightly higher than square shape. However combustion efficiency of the square bluff body is larger than the triangular one. In the second part, the effect of bluff body number (i.e. one, two and four bluff bodies) in micro scale combustor is examined on combustion characteristics. With the increasing number of bluff bodies, the outer wall temperature increases. This is because of the creation of a uniform temperature field in micro scale combustor.

Background: Ice nucleation active (INA) bacteria have play a role in atmospheric processes and participate in assort of biological precipitation cycle. The most surveys on these bacteria were from subtropical area, so, studies of INA bacteria from other area are needed. The aim of current research was isolation and identification of INA bacteria from north of Tehran, Iran to investigate their ice nucleation property.Methods: Bacterial genus were isolated from plant surface (Japan allspice) and winter precipitation (snow and rain) after culturing on BHI medium and incubated in a various temperatures (4, 10, 15, 20 and 25oC) for 24-96 hours. Droplet freezing method was used to screen potential of ice nucleation producing bacteria. 16S rRNA analysis was applied to confirm genus and species of the isolates. Outer membrane protein of ice nucleation positive strain was purified and identified by SDS-PAGE method.Results: The results showed that among 50 isolates, 40 strains had the ability to produce ice nucleation and 10 strains showed extremely high ice nucleation activity. Gram positive cocobacilli (5%), gram negative bacilli and gram positive cocci (25%) were determined as the least and the most microbial populations, respectively.Conclusion: The best strain was a gram-negative rod shape with the ability of complete freezing of water in less than 5 minutes. It was identified as Pseudomonas syringea based on 16S rRNA gene sequencing. Selected isolate in this research could be a promising tool for biopercipitation.