Papers by Keyword: MIC

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Authors: Cheng Chen, Can Qun Yang, Wen Ke Yao, Jin Qi, Qiang Wu
Abstract: Utilizing iterative method to solve the large sparse linear systems is the key to many practical mathematical and physical problems. Recently, Intel released Xeon Phi, a many-core processor of Intel’s Many Integrated Core (MIC) architecture, comprises 60 cores and supports 512-bit SIMD operation. In this work, we aim at accelerating an iterative algorithm for large spare linear system, named PQMRCGSTAB, by using both Xeon Phi’s 8-way vector operation and dense threads. Then, we propose three optimizations to improve the performance: data prefetching to hide the data latency, vector register reusing, and SIMD-friendly reduction. Our experimental evaluation on Xeon Phi delivers a speedup of close to a factor 6 compared to the Intel Xeon E5-2670 octal-core CPU running the same problem.
Authors: Ai Mei Yang, Xiao Long Shi, Jing Sun, Lin Yang, Yun Men
Abstract: The antibacterial activity of extracts from Gentiana farreri Balf. f. was studied using Bnfillus licheniformis, Aeruginosus Bacillus, Staphylococcus aureus, Streptococcus pneumoniae and Escherichia coli as the test bacteria by Oxford cup. Meanwhile, the MIC of each extraction part of the ethanol extracts were determined. The results showed that the EtOAc extracts displayed the best antibacterial activity, the n-BuOH extracts had the lower activity, and the petroleum ether extracts had the lowest activity. The antibacterial activity enhanced along with the increase of sample concentration.
Authors: Christian Thyssen, David Holuscha, Jens Kuhn, Friederike Walter, Wolfram Fürbeth, Wolfgang Sand
Abstract: Bioleaching and biocorrosion are based on similar biochemical processes. Microbe-surface interaction, biofilm formation and concomitant extracellular polymeric substance (EPS) production gained increasing interest in the past decades. Nowadays it is generally accepted that biofilm formation and an accompanying formation of manganese oxides by manganese oxidizing bacteria such as Leptothrix spp. account for one type of pitting corrosion of stainless steel (SS). However, little is known about biofilm formation, EPS composition of manganese oxidizing microorganisms and their influence on microbiologically influenced corrosion. Consequently, we studied biofilm formation of Leptothrix discophora, the biooxidation of manganese in biofilms on floating filters as well as biofilm formation on stainless steel and the involved corrosion processes. Cells were visualized by epifluorescence (EFM) or confocal laser scanning –microscopy (CLSM). Additionally, the influence of biofilm formation and biooxidation of manganese by L. discophora on the open circuit potential (OCP) and pitting potential (Epit) of stainless steel was measured using a 3 electrode setup. L. discophora grew well in biofilms on floating filters and on SS coupons and incorporated in both conditions Mn2+ in the form of MnO2 from the bulk phase into the biofilm. OCP measurements of actively manganese-oxidizing biofilms on stainless steel showed a significant ennoblement of ≥200 mV.
Authors: Xiao Sheng Shen, Bei Lei Qian, Wei Hua Wu, You Qiong Cai, Cheng Chu Liu
Abstract: In this study, the survival of Vibrio parahaemolyticus in suspension in the presence of tea-polyphenols for 6h was first examined. The shucked oysters containing V. parahaemolyticus then were exposed to 2048μg/mL , 1024 μg/mL and 512 μg/mL tea-polyphenols for 4h and the population of V. parahaemolyticus in shucked oysters was determined every 1h. In addition, shucked oysters containing V. parahaemolyticus exposed into the dose of 1024 μg/mL tea-polyphenols were held at various temperature (0, 5, and 20°C) to examine survival of V. parahaemolyticus every 6h till 24h. Populations of V. parahaemolyticus in oyster were determined using 3-tube most probable number (MPN) method. The study found that the MIC of tea-polyphenols to Vibrio parahaemolyticus suspension is 1024 μg/mL; when exposed to 2048 μg/mL, 1024 μg/mL and 512 μg/mL tea-polyphenols for 4h, the population of V. parahaemolyticus in shucked oysters decreased by 3.29,2.43 and 1.84 Log10MPN/g respectively; 0, 5 and 20°C, 1024 μg/mL tea-polyphenols can decrease the population of V. parahaemolyticus in shucked by 4.10, 3.32 and 3.00Log MPN/g at 24th h. Sensory analysis showed that treatments of tea-polyphenols at concentrations 1024μg/mL did not cause negative effects on taste of oyster meat. These results indicated that tea-polyphenols have bactericidal effects against V. parahaemolyticus and can be applied to shucked oysters to reduce contamination of V. parahaemolyticus.
Authors: Lin Yang, Jing Long, Wei Juan Li, Ai Mei Yang, Zhong Duo Yang, Xiao Feng Liu, Rui Xue Zou
Abstract: In this study, 23 endophytic fungus were isolated from Anemone tomentosa. The antibacterial activity of the endophytic fungi were tested and analyzed by filter paper method. The results showed that the endophytic fungi from Anemone tomentosa had broad antibiogram and strong inhibited Gram-positive bacteria and Gram-negative bacteria, especially the mycelia extract of root-1, the ethyl acetate and the n-BuOH extracts of root-8. So the endophytic fungi from Anemone tomentosa could be an important resource for developing antimicrobial products.
Authors: Xin Wang, Jin Xu, Cheng Sun
Abstract: Corrosion behavior of steel Q235 was investigated during natural evaporation in soils with and without sulfate reducing bacteria (SRB) by microbiological analysis, electrochemical impedance spectroscopy (EIS), energy dispersive X-ray analysis (EDXA) and electron-probe X-ray microanalysis (EPMA). The results show that during natural evaporation, oxygen content increases, amounts of SRB decrease, and the corrosion rates of steel Q235 increase with decreasing humidity of soils with and without SRB. Increments of the corrosion rates are much bigger in soils with SRB than those without SRB.
Authors: Lin Yang, Wei Juan Li, Jing Long, Ai Mei Yang, Zhong Duo Yang, Xiao Feng Liu, Dong Hua, Wen Juan Wang, Jun Hong Ma
Abstract: 20 strains of endophytic fungi were isolated from roots and stems of Ephedra intermedia. After fermentation these strains, fermentation broth and mycelium were extracted by ethyl acetate, n-butanol and methyl alcohol, producing 60 extracts. Then the antibacterial activity of these extracts was researched, the result found that 33 extracted samples could evidently inhibit the growth of six different bacteria, accounted for 55%. The MIC of ethyl acetate extract of J109 was 0.15625mg/mL to five test bacterial expect Streptococcus uberi.
Authors: Edward C. Hill, Graham C. Hill
Abstract: Microbial contamination and growth in distillate fuels has been described for seventy years. The consequences have ranged from fouling of filters and injectors, to engine malfunction and damage, fuel gauge malfunctions and aggravated corrosion of engines, fuel tanks, equipment and facilities. The types of microbes present vary with the differences in fuel composition and differences in storage and use conditions. Anti-microbial strategies have traditionally included prevention by ‘good housekeeping’ and ‘fire-brigade’ applications of biocides when there are operational problems. Since 2002, first the aviation industry and later fuel suppliers and some militaries, have used simple on-site microbiological tests to monitor fuel and fuel systems and use the results to take remedial actions before operational problems occur. This paper will review our latest knowledge of microbially influenced corrosion and of the new anti-microbial strategies which are being successfully implemented to prevent it.
Authors: Kripa Suvarna, K. Rajendra Udupa, A.O. Surendranathan
Abstract: Austenitic stainless steels are susceptible to microbiologically influenced corrosion (MIC) when they are in contact with sea water. This is due to the changes in the chemistry of the environment at the metal surface because of the settlement and activities of microorganisms. The thrust of our work was in understanding the changes in the electrochemical behaviour of a type 316L stainless steel in the presence of a natural biofilm as well as the influence of metallurgical characteristics on microbial adhesion and MIC. The presence of a biofilm on material surface can influence the corrosion behaviour since the value of a given parameter such as temperature, pressure, concentration of a solute and pH at the water /substrate interface under the biofilm may be different from that in the bulk environment. The non-uniform nature of biofilm thus helps in generating heterogeneity in the environment at the surface. Thus, biofilms are known to aid in the initiation of corrosion, change the mode of corrosion or cause changes in the corrosion rate. Bacteria Arthobacter nicotinae (An) and algae Chlorella pyrenoidosa (Cp) were used for the study and bio film formed due to these showed pit initiation and increase in corrosion rate as time proceeds. 316L base metal (BM) and weld metal (WM) as received and after heat treated at 450°C for 10000 hours were studied and corrosion evaluation was done. Heat treated WM showed severe response to corrosion compared to as received WM. Key Words: MIC, AISI 316L SS, biofilm, weld metal, localized corrosion.
Authors: Xue Ting Chang, Shou Gang Chen, Yan Sheng Yin
Abstract: Electrochemical impedance spectrum (EIS) and potentiodynamic polarization curve were applied to invest the corrosive behavior of Fe3Al/ZrO2 composites with different components in marine microbial medium. The results indicated that the existence of microbiology negatively moved the open circle potential. When the composites contained 30% (wt %) ZrO2, the passive film on electrodes surface was the thickest one, even after 25 days the material was still protected. When the content of ZrO2 was 90%, Fe3Al was in the least content, after 25 days the passive film has disappeared, but the material was still not eroded because of the high hardness and corrosion-resistant properties of ZrO2. When the content of ZrO2 was 80%, the passive film was partly damaged, which could lead to more serious local corrosion.
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