Although approximately 100 physical measurands can be detected using physical sensors, in the case of chemosensors this number is higher by several orders of magnitude. The types of chemosensors that can be used in an e-nose need to respond to odorous molecules in the gas phase, which are typically selleck chem volatile organic molecules with different relative molar masses [3].The ideal sensors to be integrated in an electronic nose should fulfill the following criteria [7]: high sensitivity towards chemical compounds, that is, similar to that of the human nose (down to 10?12 g/mL); low sensitivity towards humidity and temperature; medium selectivity, they must respond to different compounds present in the headspace of the sample; high stability; high reproducibility and reliability; short reaction and recovery time; robust and durable; easy calibration; easily processable data output; small dimensions.

As the sensors are designed for industrial purposes, especially as on-line systems, a minimal working temperature with low power consumption, a high safety level, and low manufacturing costs present valuable advantages. Most manufacturers are looking for highly selective sensors. In the case of an electronic nose, every compound present Inhibitors,Modulators,Libraries in the gaseous phase should be detecte
Wireless sensor networks (WSNs) have a wide range of potential applications, including environment monitoring, military surveillance, and remote medical systems [1]. The energy-efficient routing has become a key issue attracting recent interest, since the battery of nodes is the most critical limiting Inhibitors,Modulators,Libraries factor [2�C5].

Power failure of a node affects its ability to forward the data packets of others as well as sending its own messages. Thus, the overall network lifetime will be seriously reduced. For this Inhibitors,Modulators,Libraries reason, extensive research has focused on how to prolong the network lifetime [6�C12].Much of the research on energy efficient routing Inhibitors,Modulators,Libraries for WSNs has several drawbacks. A single-hop clustering algorithm [13] can reduce energy consumption since only a fraction of the nodes, called cluster heads, communicate with the sink in one hop. However, a single-hop clustering algorithm is impractical, because nodes at a distance greater than one hop from the sink do not have adequate transmission power to communicate with the sink [14].

Although the multi-hop model would be a more GSK-3 practical approach to solve this problem, it can increase communication overhead and costs required to obtain the routing information in large-scale networks. In view of these issues, routing through a backbone reduces communication overhead and overall energy consumption selleck chemicals llc for WSNs [15�C17]. However, backbone nodes require extra functionality and therefore consume more energy compared with other nodes in the network. Unbalanced energy consumption among the sensor nodes may cause network partition and node failures where transmission from some sensors to the sink node becomes blocked.