Diodicity mechanism Tesla-type microvalves: a CFD study

Microvalve is one of the most important components in microfluidic systems and micropumps. In this paper, three-dimensional incompressible flow through a Tesla-type microvalve is simulated using FLUENT computational fluid dynamic package. The flow is laminar and SIMPLE algorithm is used. The second-order upwind method is implemented for discretizing convective terms. The diodicity mechanism is investigated in detail for three different microvalves. Effect of several series Tesla-type microvalves on diodicity is also studied. The numerical analyses reveal that the mechanism of diodicity occurs at the T-junction and side channel. If inlet and outlet channels are eliminated, diodicity can be increased by 2. Pressure field analysis shows that the pressure drop is much severe at the junction of the reverse flow compared to the forward flow. The obtained numerical results are compared with those of experimental and a good agreement between them is noticed

Diodicity mechanism Tesla-type microvalves: a CFD study

Microvalve is one of the most important components in microfluidic systems and micropumps. In this paper, three-dimensional incompressible flow through a Tesla-type microvalve is simulated using FLUENT computational fluid dynamic package. The flow is laminar and SIMPLE algorithm is used. The second-order upwind method is implemented for discretizing convective terms. The diodicity mechanism is investigated in detail for three different microvalves. Effect of several series Tesla-type microvalves on diodicity is also studied. The numerical analyses reveal that the mechanism of diodicity occurs at the T-junction and side channel. If inlet and outlet channels are eliminated, diodicity can be increased by 2. Pressure field analysis shows that the pressure drop is much severe at the junction of the reverse flow compared to the forward flow. The obtained numerical results are compared with those of experimental and a good agreement between them is noticed

Post Season Pricing as a Mechanism for Risk Sharing: Evidences from Laboratory Experiments in Bristol Bay Sockeye Salmon Ex-Vessel Market

We develop a theoretical model to address the effects of different market structures on the ex-vessel prices and consequently how this would impact the risk-sharing mechanism for harvesters and processors in fisheries. We focus our research on two market structures, price-at-landing (PL) and post-season pricing (PS). PL market structure is where ex-vessel prices are determined between harvesters and processors prior to realization of wholesale prices. PS market structure, modelled after Bristol Bay salmon ex-vessel market, is where a harvester signs a contract with a processor prior to the season without knowing how much they are getting paid at the end of the season. Then the ex-vessel prices are determined by processors after realization of wholesale prices. Our model show that when there is no uncertainty in wholesale prices, PL yields higher or equal ex-vessel prices than PS. With certainty, the bargaining power harvesters forgone by signing a contract may be translated into processors' market power in which may result in lower ex-vessel prices. When we introduce uncertainty in wholesale prices, PS yields higher ex-vessel prices than PL. With uncertainty, PS functions as a way for risk-adverse processors to share part of their wholesale price uncertainties with harvesters. In exchange, harvesters get higher ex-vessel prices. We also test out the model in a controlled-laboratory experiment setting. Our experiment data supports conjectures obtained from the theoretical model

Peptide deformylase inhibitors of Mycobacterium tuberculosis: synthesis, structural investigations, and biological results.

Bacterial peptide deformylase (PDF) belongs to a subfamily of metalloproteases catalyzing the removal of the N-terminal formyl group from newly synthesized proteins. We report the synthesis and biological activity of highly potent inhibitors of Mycobacterium tuberculosis (Mtb) PDF enzyme as well as the first X-ray crystal structure of Mtb PDF. Structure-activity relationship and crystallographic data clarified the structural requirements for high enzyme potency and cell based potency. Activities against single and multi-drug-resistant Mtb strains are also reported