Converting Daily Rainfall Data to Sub-daily—Introducing the MIMD Method

One of the most important analysis in many hydrological and agricultural studies is to convert the daily rainfall data into sub-daily (hourly) because in many rainfall stations, only the daily rainfall data are available and for a comprehensive rainfall analysis, these data should be converted to sub-daily. Many experimental and analytical methods are available for this conversion but one of the simplest yet accurate ones has been proposed by the Indian Meteorological Department (IMD). Since the IMD method has shown low accuracy in some regions, in this study, the IMD method is modified to a single parameter equation, called Modified Indian Meteorological Department (MIMD) in order to improve the accuracy of the conversion. For this reason, the parameter is calibrated so that the maximum correlation between observed and estimated values is achieved. Five stations in different regions with different climatic conditions were selected so that the daily and sub-daily rainfall data were available in each of them. Then, the parameter of the MIMD method was derived for each station. The results were compared with both observed data and IMD method and it was shown that the mean correlation coefficient of MIMD and IMD methods were 0.9 and 0.73 respectively for 12-h rainfall depth which indicated that the accuracy of the MIMD method in estimation of sub-daily rainfall depths was significantly increased. Moreover, the results showed that the accuracy of the MIMD method decreases as rainfall duration decreases.

     

Improving the Pressurized Flushing Efficiency in Reservoirs: an Experimental Study

Sediment flushing in many reservoirs of the world is accomplished with low efficiency. In this study, a new configuration was proposed for reservoir bottom outlet to increase the pressurized flushing efficiency. In the new configuration, a projecting semi-circular structure was connected to the upstream edge of bottom outlet. It was observed that by employing the projecting bottom outlet, the sediment removal efficiency increased significantly compared to the flushing via typical bottom outlet. In the case of new-configuration bottom outlet with L _sc /D _outlet  = 5.26 and D _sc /D _outlet  = 1.32, the dimensionless length, width and depth of flushing cone increased 280%, 45% and 14%, respectively, compared to the reference test. The proposed structure can ensure the sustainable use of reservoirs.     

Pervaporative removal of acrylonitrile from aqueous streams through polydimethylsiloxane membrane

This study describes the successful separation of acrylonitrile (ACN) from dilute aqueous streams using pervaporation process. The influences of ACN feed concentration, permeate pressure, operating temperature, feed flow rate and membrane thickness on the membrane separation performance were investigated. The results showed that with an increase in ACN concentration in the feed solution, the permeation flux of ACN increased while the enrichment factor decreased. It was also indicated that increasing the permeate pressure reduced the driving force for mass transfer and consequently the permeation flux dropped while the enrichment factor enhanced. Polydimethylsiloxane membranes used in this study showed very good properties in the separation process, leading to enrichment factors in the range of 70-140. Furthermore, the activation energy for pervaporation of both ACN and water calculated from Arrhenius plot indicated that the permeation of water through the membrane was more temperature dependant than ACN.     

Efficient biodegradation of naphthalene by a newly characterized indigenous Achromobacter sp. FBHYA2 isolated from Tehran Oil Refinery Complex

A bacterial strain, FBHYA2, capable of degrading naphthalene, was isolated from the American Petroleum Institute (API) separator of the Tehran Oil Refinery Complex (TORC). Strain FBHYA2 was identified as Achromobacter sp. based on physiological and biochemical characteristics and also phylogenetic similarity of 16S rRNA gene sequence. The optimal growth conditions for strain FBHYA2 were pH 6.0, 30 °C and 1.0% NaCl. Strain FBHYA2 can utilize naphthalene as the sole source of carbon and energy and was able to degrade naphthalene aerobically very fast, 48 h for 96% removal at 500 mg/L concentration. The physiological response of Achromobacter sp., FBHYA2 to several hydrophobic chemicals (aliphatic and aromatic hydrocarbons) was also investigated. No biosurfactant was detected during bacterial growth on any aliphatic/aromatic hydrocarbons. The results of hydrophobicity measurements showed no significant difference between naphthalene- and LB-grown cells. The capability of the strain FBHYA2 to degrade naphthalene completely and rapidly without the need to secrete biosurfactant may make it an ideal candidate to remediate polycyclic aromatic hydrocarbon (PAH)-contaminated sites.     

National culture, networks and ethnic entrepreneurship: A comparison of the Indian and Chinese immigrants in the US

This paper uses a combination of national cultural frameworks and social capital theory to explain the formation and management of entrepreneurial ventures among immigrant communities. The varying rates of venture formation and performance among different ethnic groups points to the role that the different dimensions of culture play in how immigrants use their social networks to start such firms. We use the specific example of the Indian and Chinese communities in the US to demonstrate this effect and explain how businesses created by members of these communities could have potentially different ways of starting and operating that can be directly traced to the differences in cultural orientation of their owners. What emerges can be summarized as: (a) different immigrant communities have different ways of accumulating and using social capital in starting and managing their ethnic ventures; (b) these dissimilarities manifest themselves in variations in the motives for forming these ventures, human resource practices and termination rates; and (c) that these variations can partly be explained by the differences in their respective national cultures.     

Application of Bayesian Decision Networks for Groundwater Resources Management Under the Conditions of High Uncertainty and Data Scarcity

This paper presents management of groundwater resource using a Bayesian Decision Network (BDN). The Kordkooy region in North East of Iran has been selected as study area. The region has been sub-divided into three zones based on transmissivity (T) and electrical conductivity (EC) values. The BDN parameters: prior probabilities and Conditional Probability Tables - CPTs) have been identified for each of the three zones. Three groups of management scenarios have been developed based on the two decision variables including “Crop pattern” and “Domestic water demand” across the three zones of the study area: 1) status quo management for all three zones represent current conditions; 2) the effect of change in cropping pattern on management endpoints and 3) the effect of future increased domestic water demand on management endpoints. The outcomes arising from implementing each scenario have been predicted by use of the constructed BDN for each of the zones. Results reveal that probability of drawdown in groundwater levels of southern areas is relatively high compared with other zones. Groundwater withdrawal from northern and northwestern areas of the study area should be limited due to the groundwater quality problems associated with shallow groundwater of these two zones. The ability of the Bayesian Decision Network to take into account key uncertainties in natural resources and perform meaningful analysis in cases where there is not a vast amount of information and observed data available – and opportunities for enabling inputs for the analysis based partly on expert elicitation,emphasizes key advantages of this approach for groundwater management and addressing the groundwater related problems in a data-scarce area.     

Dynamic capabilities in entrepreneurial firms: A case study approach

Three entrepreneurial case studies in Canada show that changes in the environment??such as changes in customers?? needs and changes in competitive products??are the major sources of opportunities. To recognize and exploit these opportunities, the firm needs entrepreneurial capabilities. At the same time, to gain long-run competitive advantage, the firm needs dynamic capabilities. The case findings show that entrepreneurial capabilities have circular and iterative relationship with dynamic capabilities??each reinforces the other. The more often the iteration takes place, the stronger entrepreneurial capabilities and dynamic capabilities are. Further, the study builds on the extant literature and develops a new method to capture dynamic capabilities through capturing changes in ordinary capabilities.     

Social Planner’s Solution for the Caspian Sea Conflict

This paper evaluates the proposed alternatives for sharing the Caspian Sea from the social planner’s or systems-level perspective with respect to the stakeholders’ utilities from the oil and natural gas resources of the sea. Different multi-criteria decision-making methods, namely dominance, maximin, lexicography, simple additive weighting, and TOPSIS are applied to determine the social planner’s ranking of these alternatives. Results suggest the Condominium governance regime as the most promising division method. Bankruptcy rules and cooperative game theory methods can be considered as the other socially optimal resolutions to the conflict over sharing the Caspian Sea energy resources among its five littoral countries. Consideration of these methods in negotiations may help with resolving the existing deadlock, which has been in place for two decades.     

Debt, growth and inflation in large European economies: a vector auto-regression analysis

This paper attempts to empirically test the hypothesis that whether debt matters in the EU. This has been performed by examining the potential adverse effects of debt in large European economies on investment, inflation and growth. Using the hybrid cointegration and vector autoregressive models, the findings, based on the period 1970–97, suggest that debt causes significant adverse effects on investment, but its impact on growth is not clear-cut. Moreover, debt appears to be inflationary in most cases in the long run, though produces no clear short run pattern on inflation.