a laboratory stirred tank bioreactor with six single and dual-impeller configurations was tested to obtain the optimum operating conditions for future biological processes. six impeller combinations consisting of three basic impeller types, namely rushton turbine (rt), pitched 4blade (p4b) and pitched 2blade (p2b) downward flow were investigated in 1.77 l bioreactor working volume. power consum...

Conventional anaerobic digesters (ADs) treating dairy manure are fed with raw or fermented manure rich in volatile fatty acids (VFAs). In contrast, pre-fermented AD (PF-AD) is fed with the more recalcitrant, fiber-rich fraction of manure that has been pre-fermented and depleted of VFAs. Thus, the substrate of PF-AD may be likened to a lean diet rich in fibers while the pre-fermentation stage fe...

The Minimum Cost Network Flow Problem (MCNFP) constitutes a wide category of network flow problems. A Dual Network Exterior Point Simplex Algorithm (DNEPSA) for the MCNFP is presented here, together with some computational results. Similarly to the classical Dual Network Simplex Algorithm (DNSA), the new algorithm starts with a dual feasible tree-solution and, after a number of iterations, it p...

Field and flow programming and their combination, dual programming, are shown to extend the particle size range to which a single flow/hyperlayer field-flow fractionation (FFF) run is applicable to approximately 1-50 microns. The rationale for programming flow/hyperlayer FFF (or other forms of lift hyperlayer FFF) is to expand the diameter range of micron size particles that can be resolved in ...

it is several decades that the application of membrane processes for gas separation has become a great concern within industries. among them, the polymeric membranes of different structures have played the most important role. such application has been widely extended to gas separation and due to the necessity of both; prediction of the behavior of these processes and recognition of the effecti...

In this paper, a system for efficient removal of carbon dioxide by hollow fiber membranes is proposed. The system is compact, and it is very useful for application in the offshore energy industries. In particular, it is used to removing CO2 from the exhaust of power generation facilities on offshore platforms.The proposed dual membrane contactor contains two types of membranes (polypropylene me...

What effect does variation in dual citizenship policies of both sending and receiving societies have on bilateral migration flow? Employing a modified gravity model, we use a new dual citizenship database to examine the effects of allowance within 14 Organisation for Economic Co-Operation and Development (OECD) receiving states and more than 100 sending states between 1980 and 2006. We show tha...