Plant growth promotion effect of plasma activated water on Lactuca sativa L. cultivated in two different volumes of substrate

Plasma activated water (PAW) can represent an alternative to chemical fertilizers in agriculture. The effects of PAW treatment applied in two concentrations (1.5 or 3.0 mg L−1 NO3−) on some morphological, physiological, biochemical parameters and yield of Lactuca sativa L. grown in two different pot volumes (400 or 3200 cm3) were investigated in this study. The results showed that both PAW concentrations did not influence the germination, once the process was initiated. Positive effects of the treatments were registered on the length of radicle and hypocotyls of lettuce at a concentration of 1.5 mg L−1 NO3− (PAW I), the chlorophyll content was significantly increased at a concentration of 3.0 mg L−1 NO3− (PAW II) and bigger pot volume, also the foliar weight and area. No significant differences between the treated and untreated plants were recorded for the root weight, leaf length and width. The dry weight was significantly higher for the lettuce treated with PAW I and II grown in big volume pots at 57 days after transplanting (DAT) and small volume pots at 64 DAT. The nitrites content of the lettuce grown in big pots was lower than of the lettuce grown in small pots, regardless of the PAW treatment. Contrary, the nitrates content was higher in the lettuce grown in big pots (up to 36.4 mg KNO3/g DW), compared to small pots (under 0.3 mg KNO3/g DW)

Robust node localization for wireless sensor networks

The node localization problem in Wireless Sensor Networks has received considerable attention, driven by the need to obtain a higher location accuracy without incurring a large, per node, cost (dollar cost, power consumption and form factor). Despite the efforts made, no system has emerged as a robust, practical, solution for the node localization problem in realistic, complex, outdoor environments. In this paper, we argue that the existing localization algorithms, individually, work well for single sets of assumptions. These assumptions do not always hold, as in the case of outdoor, complex environments. To solve this problem, we propose a framework that allows the execution of multiple localization schemes. This “protocol multi-modality ” enables robustness against any single protocol failure, due to its assumptions. We present the design of the framework, and show a 50% decrease in localization error in comparison with state of art node localization protocols. We also show that complex, more robust, localization systems can be build from localization schemes that have limitations

A Hybrid Multicast Routing for Large Scale Sensor Networks with Holes

In this article, we present RE2 MR, the first hybrid multicast routing protocol that builds on the strengths of existing topology-based, hierarchical and geographic multicast solutions, while addressing their limitations. In RE2 MR, the multicast path search problem is formulated as the capacitated concentrator location problem (CCLP) which yields the network topology that minimizes the sum of path lengths from the multicast root to multicast members. Furthermore, its trajectory-based lightweight hole detection (THLD) discovers deployment area irregularities (i.e., network holes) that affect its solution and autonomously take them into account to generate updated routing paths, and its Energy-efficient Packet Forwarding (EPF) and Multi-level Facility Computation (MFC) reduce computational and communication overheads. We implement RE2MR in TinyOS and evaluate it extensively using TOSSIM for relatively large-scale simulations (400 nodes); we also implement RE 2MR on real-hardware and perform experiments on a testbed consisting of 42 TelosB motes. Through the simulations and experiments on real-hardware, we demonstrate that RE2MR reduces the energy consumption by up to 57 percent and the end-to-end delay by up to 8 percent, when compared with the state-of-the-art multicast routing protocols

Destination-based Cut Detection in Wireless Sensor Networks

Abstract—Wireless Sensor Networks (WSNs) often suffer from disrupted connectivity caused by its numerous aspects such as limited battery power of a node and unattended operation vulnerable to hostile tampering. The disruption of connectivity, often referred to as network cut, leads to ill-informed routing decisions, data loss, and waste of energy. A number of protocols have been proposed to efficiently detect network cuts; they focus solely on a cut that disconnects nodes from the base station. However, a cut detection scheme is truly useful when a cut is defined with respect to multiple destinations (i.e., target nodes), rather than a single base station. Thus, we extend the existing notion of cut detection, and propose an algorithm that enables sensor nodes to autonomously monitor the connectivity to multiple target nodes. We introduce a novel reactive cut detection solution, the Point-to-Point Cut Detection, where given any pair of source and destination, a source is able to locally determine whether the destination is reachable or not. Furthermore, we propose a lightweight proactive cut detection algorithm specifically designed for a small set of target destinations. We prove the effectiveness of the proposed algorithms through extensive simulations. Keywords-Wireless sensor networks; cut detection; energy efficiency I