The design and testing of a 400 mm diameter contra-rotating fan unit was undertaken to study the flow behavior through the contra-rotating fans, and to find ways and means of improving their design and performance. The performance characteristics of the two-fan unit have shown that large overall stall margins can be achieved. Also, the effect of axial gaps showed that at the design speed combination best performance was observed at an axial gap of 50% of the 1st Fan chord. Studies on the 2nd fan exit flow field, performance characteristics of individual fans and casing boundary layer development have been made. Significant performance enhancement is observed with serration on 2nd fan rotor blade surface. When casing boundary layer suction is employed in between the two blades, the 2nd fan exit flow shows better uniformity and increased total pressure at all radii. However, to obtain a large operating range, careful optimization of the 2nd rotor blade design would be required, taking into account peculiarities shown by the present study in variation of deviation and exit flow angles of the individual fans, and casing boundary layer development with increased axial pressure gradient.

It is difficult to incorporate multidimensional effect of the ground motion in the design and response analysis of structures. The motion trajectory in the corresponding multi-dimensional space results in time variant principal axes of the motion and defies any meaningful definition of directionality of the motion. However, it is desirable to consider the directionality of the ground motion in assessing the seismic damageability of bridges which are one of the most vulnerable components of highway transportation systems. This paper presents a practice-oriented procedure in which the structure can be designed to ensure the safety under single or a pair of independent orthogonal ground motions traveling horizontally with an arbitrary direction to structural axis. This procedure uses nonlinear time history analysis and accounts for the effect of directionality in the form of fragility curves. The word directionality used here is different from "directivity" used in seismology to mean a specific characteristic of seismic fault movement.

and Shanghai, China-we engage in an intersectional analysis of the gendered impacts of the Covid-19 pandemic in women's everyday lives. Our research employs a variety of context-specific methods, including virtual methods, phone interviews, and socially-distanced interviews to engage women living in neighbourhoods characterized by underdevelopment and economic insecurity. While existing conditions of precarity trouble the beforeand-after terminology of Covid-19, across the five cities the narratives of women's everyday lives reveal shifts in spatial-temporal orders that have deepened gendered and racial exclusions. We find that limited mobilities and the different and changing dimensions of production and social reproduction have led to increased care work, violence, and strained mental health. Finally, we also find that social reproduction solidarities, constituting old and new circuits of care, have been reinforced during the pandemic.

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