Exploring network-level performances of wireless nanonetworks utilizing gains of different types of nano-antennas with different materials

Wireless nanonetworks are not a simple extension of traditional communication networks at the nano-scale. Owing to being a completely new communication paradigm, existing research in this field is still at an embryonic stage. Furthermore, most of the existing studies focus on performance enhancement of nanonetworks via designing new channel models and routing protocols. However, the impacts of different types of nano-antennas on the network-level performances of the wireless nanonetworks remain still unexplored in the literature. Therefore, in this paper, we explore the impacts of different well-known types of antennas such as patch, dipole, and loop nano-antennas on the network-level performances of wireless nanonetworks. We also investigate the performances of nanonetworks for different types of traditional materials (e.g., copper) and for nanomaterials (e.g., carbon nanotubes and graphene). We perform rigorous simulation using our customized ns-2 simulation to evaluate the network-level performances of nanonetworks exploiting different types of nano-antennas using different materials. Our evaluation reveals a number of novel findings pertinent to finding an efficient nano-antenna from its several alternatives for enhancing network-level performances of nanonetworks. Our evaluation demonstrates that a dipole nano-antenna using copper material exhibits around 51% better throughput and about 33% better end-to-end delay compared to other alternatives for large-size nanonetworks. Furthermore, our results are expected to exhibit high impacts on the future design of wireless nanonetworks through facilitating the process of finding the suitable type of nano-antenna and suitable material for the nano-antennas.

     

Drivers of microbial community composition in mesophilic and thermophilic temperature-phased anaerobic digestion pre-treatment reactors

Temperature-phased anaerobic digestion (TPAD) is an emerging technology that facilitates improved performance and pathogen destruction in anaerobic sewage sludge digestion by optimising conditions for 1) hydrolytic and acidogenic organisms in a first-stage/pre-treatment reactor and then 2) methogenic populations in a second stage reactor. Pre-treatment reactors are typically operated at 55–65 °C and as such select for thermophilic bacterial communities. However, details of key microbial populations in hydrolytic communities and links to functionality are very limited. In this study, experimental thermophilic pre-treatment (TP) and control mesophilic pre-treatment (MP) reactors were operated as first-stages of TPAD systems treating activated sludge for 340 days. The TP system was operated sequentially at 50, 60 and 65 °C, while the MP rector was held at 35 °C for the entire period. The composition of microbial communities associated with the MP and TP pre-treatment reactors was characterised weekly using terminal-restriction fragment length polymorphism (T-RFLP) supported by clone library sequencing of 16S rRNA gene amplicons. The outcomes of this approach were confirmed using 454 pyrosequencing of gene amplicons and fluorescence in-situ hybridisation (FISH). TP associated bacterial communities were dominated by populations affiliated to the Firmicutes, Thermotogae, Proteobacteria and Chloroflexi. In particular there was a progression from Thermotogae to Lutispora and Coprothermobacter and diversity decreased as temperature and hydrolysis performance increased. While change in the composition of TP associated bacterial communities was attributable to temperature, that of MP associated bacterial communities was related to the composition of the incoming feed. This study determined processes driving the dynamics of key microbial populations that are correlated with an enhanced hydrolytic functionality of the TPAD system.     

Effect vapor grown carbon nanofiber on thermal and mechanical properties of epoxy

In the present investigation, dynamic mechanical analysis (DMA), thermo gravimetric analysis (TGA), tensile tests, fatigue tests and the single edge notch tensile (SENT) tests were performed on unfilled, 1, 2 and 3 wt.% vapor grown carbon nanofiber (CNF) filled SC-15 epoxy to identify the loading effect on thermal and mechanical properties of the composites. DMA studies revealed that filling the 3% carbon nanofiber into epoxy can produce 65% enhancement in storage modulus at room temperature and 6 °C increase in T _g. However, TGA results show that thermal stability of composite is insensitive to the CNF content. Tensile tests were carried out at the strain rate range from 0.02 min⁻¹ to 2 min⁻¹. Results show that CNF/epoxy are strain rate sensitive materials, the modulus and tensile strength increased with increasing of strain rate. Experimental results also indicate that modulus of the nanophased epoxy increases continuously with increasing CNF content. But the 2% CNF infusion system exhibit maximum enhancement in tensile strength, fatigue performance and fracture toughness as compared with other system.     

A systolic array realization of the adaptive decision feedback equalizer

This paper presents a systolic array architecture for the adaptive decision feedback equalizer. The design is based on an algebra developed earlier by Kung and Lin (Proceedings of the Conference of Elliptic Problem Solvers, Monterey, CA, January 1983; Research Report CMU-CS-84-100, Department of Computer Science, Carnegie-Mellon University, Pittsburgh, PA, April 1983.) and is largely made up of two basic processing cells that are computationally equivalent and simple to realize. To maintain accuracy of the algorithm, the array needs to be operated by a clock with a speed twice of that the input. The increase in clock speed can, however, be exploited to reduce the total number of adders and multipliers by about 50%.     

A Mobile App Search Engine

With the popularity of mobile apps on mobile devices based on iOS, Android, Blackberry and Windows Phone operating systems, the numbers of mobile apps in each of the respective native app stores are increasing in leaps and bounds. Currently there are close to one million mobile apps across these four major native app stores. Due to the enormous number of apps, both the constituents in the app ecosytem, consumers and app developers, face problems in ‘app discovery’. For consumers, it is a daunting task to discover the apps they like and need among the huge number of available apps. Likewise, for developers, enabling their apps to be discovered is a challenge. To address these issues, Mobilewalla (MW) an app search engine provides an independent unbiased search for mobile apps with semantic search capabilities. It has also developed an objective scoring mechanism based on user and developer involvement with an app. The scoring mechanism enables MW to provide a number of other ways to discover apps—such as dynamically maintained ‘hot’ lists and ‘fast rising’ lists. In this paper, we describe the challenges of developing the MW platform and how these challenges have been mitigated. Lastly, we demonstrate some of the key functionalities of MW.     

Microwave irradiation of hazelnuts for the control of aflatoxin producing Aspergillus parasiticus

In this study, the effects of microwave treatment on hazelnuts artificially contaminated with aflatoxigenic fungi were evaluated qualitatively and quantitatively. The physical quality attributes (color, moisture loss, and sensory attributes) of microwave treated hazelnuts were also evaluated. A significant 3-log reduction in Aspergillus parasiticus contamination was observed after 120 s treatment, no or similar changes were observed during the storage of microwave treated hazelnuts under the storage conditions. While taste and odour of microwaved in shell hazelnuts were unaffected during treatment and subsequent storage, microwave treatment duration of 120 s was found to be capable of reducing fungal count of A. parasiticus on in-shell hazelnut without any noticeable change in nutritional and organoleptic properties of nuts. Based on this and the earlier study, a hybrid process is proposed, where UV-C surface treatment and vacuum assisted microwave are combined with air drying to increase the shelf life and control the quality.Industrial relevanceA hybrid industrial process is proposed, where UV-C surface treatment and vacuum assisted microwave treatment are combined to increase the shelf life and control the quality of hazelnuts.     

Nutritional and anti-nutritional components in Pachyrhizus erosus L. tuber

Tuber of Pachyrhizus erosus L., an underutilized crop, was analyzed to determine its proximate chemical composition, vitamin, mineral, and amino acid contents, and enzymatic activity. The anti-nutritional factors were also determined. The tuber had a high level of moisture, appreciable amounts of carbohydrate, crude fibre and protein and negligibly low amount of lipid. The total caloric value corresponded to 39 kcal/100 g. The amino acid profile was deficient compared to the [FAO/WHO (1973). Energy and Protein Requirements. Technical Report Series (Vol. 52, pp. 1–118). Switzerland, Geneva: WHO.] recommended pattern. The micro- and macro-nutrient analysis revealed the tuber to be potential source of potassium, sodium, phosphorus, calcium and magnesium. The tuber contained a significant amount of ascorbic acid. Thiamine, riboflavin, pyridoxine, niacin and folic acid were also detected. Very negligible contents of anti-nutrient components were observed. Comparison of these data to those of several other commonly consumed local tubers revealed that P. erosus tuber could be included in dietary formulae for man or monogastric animals, especially in those areas where carbohydrate is in short supply.