Routing for Intermittently-Powered Sensing Systems

Recently, intermittent computing (IC) has received tremendous attention due to its high potential in perpetual sensing for Internet-of-Things (IoT). By harvesting ambient energy, battery-free devices can perform sensing intermittently without maintenance, thus significantly improving IoT sustainability. To build a practical intermittently-powered sensing system, efficient routing across battery-free devices for data delivery is essential. However, the intermittency of these devices brings new challenges, rendering existing routing protocols inapplicable. In this paper, we propose RICS, the first-of-its-kind routing scheme tailored for intermittently-powered sensing systems. RICS features two major designs, with the goal of achieving low-latency data delivery on a network built with battery-free devices. First, RICS incorporates a fast topology construction protocol for each IC node to establish a path towards the sink node with the least hop count. Second, RICS employs a low-latency message forwarding protocol, which incorporates an efficient synchronization mechanism and a novel technique called pendulum-sync to avoid the time-consuming repeated node synchronization. Our evaluation based on an implementation in OMNeT++ and comprehensive experiments with varying system settings show that RICS can achieve orders of magnitude latency reduction in data delivery compared with the baselines

The stability analysis of blasting excavation in short distance on water diversion tunnel underpassing Jinduicheng Molybdenum Mine

To investigate effect induced by blasting in Jinduicheng molybdenum mine on the Dongchuan river diversion tunnel, the tunnel vibration has been monitored. According to the actual conditions, the corresponding numerical simulation is performed in FLAC3D, and dynamic response of the lining and surrounding rock of the diversion tunnel caused by blasting load is analyzed. The variation of vibration velocity in the later stage of tunnel under the action of existing blasting scale is predicted, when the vertical distance between blasting source and diversion tunnel is 50 m, the velocity of tunnel vibration reaches the critical value. The blasting scheme of mine production can be modified according to the practical distance between the explosion source and the diversion tunnel

Adsorption of Phosphate from Aqueous Solution Using an Iron-Zirconium Binary Oxide Sorbent

In this study, an iron-zirconium binary oxide with a molar ratio of 4:1 was synthesized by a simple coprecipitation process for removal of phosphate from water. The effects of contact time, initial concentration of phosphate solution, temperature, pH of solution, and ionic strength on the efficiency of phosphate removal were investigated. The adsorption data fitted well to the Langmuir model with the maximum P adsorption capacity estimated of 24.9 mg P/g at pH 8.5 and 33.4 mg P/g at pH 5.5. The phosphate adsorption was pH dependent, decreasing with an increase in pH value. The presence of Cl-, SO (4) (2-) , and CO (3) (2-) had little adverse effect on phosphate removal. A desorbability of approximately 53 % was observed with 0.5 M NaOH, indicating a relatively strong bonding between the adsorbed PO (4) (3-) and the sorptive sites on the surface of the adsorbent. The phosphate uptake was mainly achieved through the replacement of surface hydroxyl groups by the phosphate species and formation of inner-sphere surface complexes at the water/oxide interface. Due to its relatively high adsorption capacity, high selectivity and low cost, this Fe-Zr binary oxide is a very promising candidate for the removal of phosphate ions from wastewater