Wireless Sensor Networks (WSNs) are characterized by having scarce resources. The usual way of designing network functions is to consider them isolatedly, a strategy which may not guarantee the correct and efficient operation of WSNs. For this reason, in this paper we propose an integrated design of network functions. We take two important WSN functions -density control and routing -as an example and present two approaches to integrate them. In particular, we present two solutions, named RDC-Sync and RDC-Integrated, which integrate a geographical density control algorithm with tree routing. The simulations experiments performed prove that the integrated design improves the network performance, especially when density control and routing are fully integrated.
Background: Carbon nanotubes (CNTs) are novel materials with considerable potential in many areas related to nanomedicine. However, a major limitation in the development of CNT-based therapeutic nanomaterials is a lack of reliable and reproducible data describing their chemical and structural composition. Knowledge of properties including purity, structural quality, dispersion state, and concentration are essential before CNTs see widespread use in in vitro and in vivo experiments. In this work, we describe the characterization of several commercially available and two in-house-produced CNT samples and discuss the physicochemical profiles that will support their use in nanomedicine. Methods: Eighteen single-walled and multi-walled CNT raw materials were characterized using established analytical techniques. Solid CNT powders were analyzed for purity and structural quality using thermogravimetric analysis and Raman spectroscopy. Extinction coefficients for each CNT sample were determined by ultraviolet-visible near infrared absorption spectroscopy. Standard curves for each CNT sample were generated in the 0-5 µg/mL concentration range for dispersions prepared in 1,2-dichlorobenzene. Results: Raman spectroscopy and thermogravimetric analysis results demonstrated that CNT purity and overall quality differed substantially between samples and manufacturer sources, and were not always in agreement with purity levels claimed by suppliers. Absorbance values for individual dispersions were found to have significant variation between individual single-walled CNTs and multi-walled CNTs and sources supplying the same type of CNT. Significant differences (P , 0.01) in extinction coefficients were observed between and within single-walled CNTs (24.9-53.1 mL·cm ). The results described here suggest a considerable role for impurities and structural inhomogeneities within individual CNT preparations and the resulting spectroscopic properties of their dispersions. Conclusion: Raw CNT materials require thorough analytical workup before they can be used as nanoexcipients. This applies especially to the determination of CNT purity, structure, and concentration. The results presented here clearly demonstrate that extinction coefficients must be determined for individual CNT preparations prior to their use.
In the following a new data acquisition architecture is proposed allowing high sampling rates along with a large memory data buffer. The modular design allows up to four 250 MHZ, 8-bit acquisition channels to operate in an interleaved way, achieving 1 GSPS. Each channel can acquire continuously up to 3 ME3ytes of data (or 12 MBytes when interleaved). Since several modules can coesist in an acquisition system, provision was made for several parallel operations, including trigger distribution and download of digital signal processing programs.
The TOF-tracker concept, the simultaneous measurement of accurate time and bidimensional space coordinates in a single gaseous detector, has been previously demonstrated. The detector yielded a time resolution of 77 ps σ along with a bi-dimensional position resolution of 38 µm σ over a full active area of 60 × 60 mm 2. In here, we report about a large area, 1550 × 1250 mm 2 , TOF-tracker device, tested by tracking cosmic muons, yielding a position resolution down to 1.33 mm σ, a simultaneous time resolution of 150 ps σ and 92% detection efficiency, over the entire area of the detector. The sub-millimetre electronic resolution of the readout chain suggests that the position resolution here reported could be dominated by noncorrected systematic effects and therefore it could be yet significantly improved.
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