Design and operating parameters of a fulidized bed for the combustion of municipal solid waste using standpipes air distributors

Hydrodynamic studies and combustion of simulated and actual municipal solid waste were carried out in a fluidized bed system. A wide range of parameters was investigated in hydrodynamic study after which the optimum parameters were implemented in the combustion studies. A newly fabricated standpipes air distributor (primary air inlet) was designed based on findings of the optimum orifice diameter, orifice distance and distance between pipes. Orifice diameter, orifice distance and distance between pipes of 3 mm, 10 mm and 70 mm were used in the hydrodynamic studies of circular and rectangular columns (CHS and RHS). The operating parameters investigated in the CHS and RHS included the effect of sand sizes and aspect ratios on the fluidization profile. Standpipes air distributors having the same orifice diameter and distance but with a wider pipe distance of 200 mm were used in the hydrodynamic studies of a bigger rectangular (big scale) column. Different air flow strategies were implemented to ensure good mixing between sand and samples and to investigate the penetration of the incombustibles into the sand bed. Parameters studied in the combustion of municipal solid waste included the effect of fluidizing velocity and air factor on the combustion profile in the bed as well as the freeboard region with standpipe air distributor design and dimension established from the hydrodynamic studies of a bigger scale rectangular column. Findings from the CHS and RHS showed that sand particles with mean size of 0.34 mm performed good fluidization profile compared to other coarser sand sizes. The ratio of the bed height over diameter of column (Dc) for good fluidization was determined at cDH?for the circular column whereas the ratio of the bed height (H) over the length (L) of column was observed at H<L for the rectangular columns. A two side air flow was seen as the best air flow strategy for good mixing in a bigger rectangular column. The range of fluidization number and air factor for the combustion of simulated municipal solid waste in a rectangular fluidized bed combustor was 5 – 7 mfUin which 5 mf U was found to be the optimum with air factor of 0.8 (primary air). Air factor of 0.4 (secondary air) was observed to show good temperature profile in the freeboard region for the combustion of municipal solid waste. The optimum total combined air factor for the combustion of municipal solid waste was 1.2 in which inlet primary air factor and inlet secondary air factor were 0.8 and 0.4, respectively

Fields in Motion, Fields of Friction: Tales of Betrayal and Promise from Kangra District, India

Over a period of five decades, Kangra District, located in the mountainous northern Indian state of Himachal Pradesh, has been continually si(gh)ted within different development imaginaries that have evolved at particular configurations of scale and time and been given shape within a succession of international bilateral projects. These development flows into the region have in turn fostered a plethora of competing institutions and practices, contributing their own sometimes divergent flows within an inherently mobile and “developmentalizing” terrain. While this dynamic and multi-textured terrain offers rich opportunities for partnerships forged across disparate sites, there is, I argue, a need to revisit “collaboration” as a key feminist tool for facilitating social justice and change. Widely lauded for its empowering, equalizing and transformative potential by feminist scholars, collaboration is also viewed prescriptively in terms of “success” and “failure.” Consequently, “strategies and solutions” are sought to negotiate its minefields and to resolve, often futilely, the friction that repeatedly erupts within them. In this paper, I suggest a re-viewing of friction as a valuable methodological frame within feminist collaborative research and praxis. In place of the prevalent emphasis on containing and resolving friction generated at border crossings, I contend that feminist-oriented “location work” that engages with friction and follows its routes through the fluid and fertile space of a “developmentalizing terrain” can provide promising avenues and detours for empowerment and social justice. Drawing on Tsing’s (2005) discussion of the creative role of friction across global connections, I reflect on some of the ways in which it played out as a creative source of production, interruption and mutation within two of my collaborative ventures in Kangra. In doing so, I demonstrate how an attention to the sometimes unanticipated and diversionary routes that are generated by friction within collaborative efforts, and the vistas of “betrayal” and promise that they reveal, offer valuable insights for encounters at the interface of feminist praxis, anthropology and development practice

Mean Field Equilibrium in Dynamic Games with Complementarities

We study a class of stochastic dynamic games that exhibit strategic complementarities between players; formally, in the games we consider, the payoff of a player has increasing differences between her own state and the empirical distribution of the states of other players. Such games can be used to model a diverse set of applications, including network security models, recommender systems, and dynamic search in markets. Stochastic games are generally difficult to analyze, and these difficulties are only exacerbated when the number of players is large (as might be the case in the preceding examples). We consider an approximation methodology called mean field equilibrium to study these games. In such an equilibrium, each player reacts to only the long run average state of other players. We find necessary conditions for the existence of a mean field equilibrium in such games. Furthermore, as a simple consequence of this existence theorem, we obtain several natural monotonicity properties. We show that there exist a "largest" and a "smallest" equilibrium among all those where the equilibrium strategy used by a player is nondecreasing, and we also show that players converge to each of these equilibria via natural myopic learning dynamics; as we argue, these dynamics are more reasonable than the standard best response dynamics. We also provide sensitivity results, where we quantify how the equilibria of such games move in response to changes in parameters of the game (e.g., the introduction of incentives to players).Comment: 56 pages, 5 figure