The potential of algae blooms to produce renewable gaseous fuel

Ulva lactuca (commonly known as sea letuce) is a green sea weed which dominates Green Tides or algae blooms. Green Tides are caused by excess nitrogen from agriculture and sewage outfalls resulting in eutrophication in shallow estuaries. Samples of U. lactuca were taken from the Argideen estuary in West Cork on two consecutive years. In year 1 a combination of three different processes/pretreatments were carried out on the Ulva. These include washing, wilting and drying. Biomethane potential (BMP) assays were carried out on the samples. Fresh Ulva has a biomethane yield of 183 L CH₄/kg VS. For dried, washed and macerated Ulva a BMP of 250 L CH₄/kg VS was achieved. The resource from the estuary in West Cork was shown to be sufficient to provide fuel to 264 cars on a year round basis. Mono-digestion of Ulva may be problematic; the C:N ratio is low and the sulphur content is high. In year 2 co-digestion trials with dairy slurry were carried out. These indicate a potential increase in biomethane output by 17% as compared to mono-digestion of Ulva and slurry.     

一种改进的多学习教与学优化算法

针对传统教与学算法在解决复杂多峰函数优化问题时,具有局部最优且搜索开发能力较差的缺点,提出了一种改进的多学习教与学优化算法,新算法为学员的每一维加入不同的教学因子,设计了基于学员均值比较的教师选择策略和向教师及学员学习的多学习策略。基于多个单峰和多峰函数的仿真结果表明,新算法跟传统的、改进的教与学算法相比,在稳定性、寻优精度和收敛速度方面更具优势。     

Organizational embeddedness,turnover intentions,and voluntary turnover: The moderating effects of employee demographic characteristics and value orientations

To explain why some employees who experience high embeddedness contemplate leaving their organizations and others do not, we examined the moderating effects of employee demographic characteristics (age and gender) and value orientations (individualism and risk aversion) between organizational embeddedness and turnover intentions. Turnover intentions were further expected to increase voluntary turnover. Data were collected from 643 full‐time employees at three points in time over a 12‐month time period in a wide range of organizations in Japan, a relatively low turnover context with little prior embeddedness research. Findings show that gender and risk aversion moderate the relationship between organizational embeddedness and turnover intentions, which in turn predict voluntary turnover. Copyright © 2014 John Wiley & Sons, Ltd.     

Soil microbial response to waste potassium silicate drilling fluid

Potassium silicate drilling fluids (PSDF) are a waste product of the oil and gas industry with potential for use in land reclamation. Few studies have examined the influence of PSDF on abundance and composition of soil bacteria and fungi. Soils from three representative locations for PSDF application in Alberta, Canada, with clay loam, loam and sand textures were studied with applications of unused, used once and used twice PSDF. For all three soils, applying ≥ 40 m³/ha of used PSDF significantly affected the existing soil microbial flora. No microbiota was detected in unused PSDF without soil. Adding used PSDF to soil significantly increased total fungal and aerobic bacterial colony forming units in dilution plate counts, and anaerobic denitrifying bacteria numbers in serial growth experiments. Used PSDF altered bacterial and fungal colony forming unit ratios of all three soils.