Biohydrogen production through dark fermentation from waste biomass:Current status and future perspectives on biorefinery development

Green and clean hydrogen production has become a significant focus in recent years to achieve sustainable renewable energy fuel needs. Biohydrogen production through the dark fermentation (DF) process from organic wastes is advantageous with its environmentally friendly, energy-efficient, and cost-effective characteristics. This article elucidates the viability of transforming the DF process into a biorefinery system. Operational pH, temperature, feeding rate, inoculum-to-substrate ratio, and hydrogen partial pressure and its liquid-to-gas mass transfer rate are the factors that govern the performance of the DF process. Sufficient research has been made that can lead to upscaling the DF process into an industrial-scale technology. However, the DF process cannot be upscaled at the current technology readiness level as a stand-alone technology. Hence, it requires a downstream process (preferably anaerobic digestion) to improve energy recovery efficiency and economic viability. The article also discusses the possible hydrogen purification and storage techniques for achieving fuel quality and easy accessibility. The article further tries to unfold the opportunities, challenges, and current scenario/future research directions to enhance hydrogen yield and microbial metabolism, depicting the commercialization status for biorefinery development. Finally, the current progress gaps and policy-level loopholes from the Indian perspective are highlighted by analyzing the strengths, weaknesses, opportunities, and threats

Distributed algorithms for coloring and domination in wireless ad hoc networks

Abstract. We present fast distributed algorithms for coloring and (connected) dominating set construction in wireless ad hoc networks. We present our algorithms in the context of Unit Disk Graphs which are known to realistically model wireless networks. Our distributed algorithms take into account the loss of messages due to contention from simultaneous interfering transmissions in the wireless medium. We present randomized distributed algorithms for (conflict-free) Distance-2 coloring, dominating set construction, and connected dominating set construction in Unit Disk Graphs. The coloring algorithm has a time complexity of O( ∆ log 2 n) and is guaranteed to use at most O(1) times the number of colors required by the optimal algorithm. We present two distributed algorithms for constructing the (connected) dominating set; the former runs in time O( ∆ log 2 n) and the latter runs in time O(log 2 n). The two algorithms differ in the amount of local topology information available to the network nodes. Our algorithms are geared at constructing Well Connected Dominating Sets (WCDS) which have certain powerful and useful structural properties such as low size, low stretch and low degree. In this work, we also explore the rich connections between WCDS and routing in ad hoc networks. Specifically, we combine the properties of WCDS with other ideas to obtain the following interesting applications: – An online distributed algorithm for collision-free, low latency, low redundancy and high throughput broadcasting. – Distributed capacity preserving backbones for unicast routing and scheduling.

Fifteen dimensions of health and their association with quality of life among elderly in rural villages in Maharashtra, India

Indian Journal of Gerontology34