Optimization studies on the ducted wind turbine

The concept of the Ducted Wind Turbine (DWT) has received significant research interest over the last fifty years. Several attempts to commercialize the DWT have been made in the past, but a commercial version does not exist at present. One of the primary concerns has been the size of the duct of the DWT and the economical and structural challenges relative to its design. It has been observed, both from existing as well as new experimental results at UNH, that significant reductions in the size of the duct can be achieved by better modeling the three dimensional flow in the duct. Specifically, the inherent swirling nature of the turbine wake flow is found to have significant influence on delaying the boundary layer separation in the diffuser, and thereby improving the diffuser performance considerably, concurring with Prasad and Ostrach (1971); McDonald et al. (1971); Senoo et al. (1978); Okhio et al. (1983). This improvement in diffuser performance facilitates a smaller diffuser, and hence a smaller duct. The present work addresses a DWT design optimization study in two parts: (1) a preliminary theoretical analysis showing a potential to reduce the length of the diffuser by up to 40%, and (2) experiments that were carried out on three DWT scale models that were prototyped at UNH to study the influence of swirl on the diffuser pressure recovery. Additionally, results from experiments have also shown scope of power augmentation of more than 40% through the use of a duct, compared to a same-rotor-diameter unducted turbine

Lymphotoxin-β Receptor Signaling through NF-κB2-RelB Pathway Reprograms Adipocyte Precursors as Lymph Node Stromal Cells

SummaryLymph node development during embryogenesis involves lymphotoxin-β receptor engagement and subsequent differentiation of a poorly defined population of mesenchymal cells into lymphoid tissue organizer cells. Here, we showed that embryonic mesenchymal cells with characteristics of adipocyte precursors present in the microenvironment of lymph nodes gave rise to lymph node organizer cells. Signaling through the lymphotoxin-β receptor controlled the fate of adipocyte precursor cells by blocking adipogenesis and instead promoting lymphoid tissue stromal cell differentiation. This effect involved activation of the NF-κB2-RelB signaling pathway and inhibition of the expression of the key adipogenic factors Pparγ and Cebpα. In vivo organogenesis assays show that embryonic and adult adipocyte precursor cells can migrate into newborn lymph nodes and differentiate into a variety of lymph node stromal cells. Thus, we propose that adipose tissues act as a source of lymphoid stroma for lymph nodes and other lymphoid structures associated with fat