Figures 1(a)�C(d) show that the zeolites Wortmannin mw have nearly the same morphology. Inhibitors,Modulators,Libraries In addition, the zeolites Y with different Si/Al ratios possess nearly the same surface areas, pore sizes, and densities. When the zeolites Y are exposed to NH4NO3 at 377 ppm, the electrical conductivity values increase by one order of magnitude, relative to the values when exposed to nitrogen. The electrical conductivity sensitivity, ����/��N2, increases with the increasing Si/Al ratios as shown in Table 1.Figure 1.SEM micrographs of the dPPV/zeolite Y composites having different Si/Al ratios (magnification 1,500, 15 kV).Table 1.Surface areas, pore size and electrical conductivity sensitivity of the zeolites and the electrical conductivity sensitivity when exposed to NH4NO3.

A higher Si content of the zeolite Y, as accompanied by a greater amount of cations present, a
In this paper, we present an energy-efficient Rate-Adaptive MAC (RA-MAC) algorithm for long-lived WSNs [1�C3]. The lifetime of a long-lived WSN is typically Inhibitors,Modulators,Libraries expected to be on the order of years with node duty cycles less than 1% (e.g., less than 1 sample per minute). (An earlier version of this article appeared as a poster abstract in Proceedings of the 6th European Conference on Wireless Sensor Networks (EWSN 09) [4]. This article features comprehensive design, analysis, implementation, and evaluation of proposed Rate Adaptive Media Access Protocol.)Performance of radio communication links, in terms of Packet Reception Rate (PRR) for example, are critical to the overall performance of wireless sensor networks, both in terms of network data throughput and energy consumption.

Higher layers of the Inhibitors,Modulators,Libraries network stack are designed to maximally utilize the communications link and thus require an understanding Inhibitors,Modulators,Libraries of link characteristics.A long-term water monitoring network [3] of 8 nodes monitors ground water extraction and salinity in a sugar cane growing region of north-eastern Australia. The network is unusual in that it has long radio links��in the range from 1 to 1.8 km. In late summer, researchers observed that many of the radio links go down at night, regularly. They observed no direct correlation with local climatic conditions such as precipitation or humidity measured at a nearby weather station, and speculate Brefeldin_A the problem is due to a layer of moist air above the fully grown cane which is trapping or reflecting the radio waves.

In an independent study [5], detailed work shows that the transmission range sellekchem of Mica2 motes can be reduced by a factor of 5 in high humidity conditions, including fog.Zamalloa and Krishnamachari [6] take a theoretical approach to the problem. They model the radio channel, the radio itself, and the noise floor, and show the existence of a transition region, also referred to as a ��gray area�� [7], characterised by highly variable packet reception rates. They show how the transition region limits can be determined, and that these limits are a function of the received Signal-to-Noise Ratio (SNR).