Extraction of Siphonochilus aethiopicus Essential Oil by Steam Distillation

Siphonochilus aethiopicus is an indigenous South African plant also known as African ginger. It has often been used for its medicinal properties to treat various ailments such as flu, colds, and so forth. The research aim of this study was to optimize the process parameters of steam distillation for the extraction of oil from African ginger rhizomes. This technology is the oldest and well known for extracting essential oils due to its economic viability and the higher final oil purity. The effects of operating parameters such as extraction duration, moisture content, particle size, and temperatures between 80°C and 100°C were studied for maximum oil recovery. The oil recovery of 0.61% (w/w) was achieved after 270?min of extraction time, using 6.37% (dry) moisture content of particle size 2.4?mm–4?mm at a maximum temperature of 100°C. Fick’s first law was used to mathematically model the experimental data of this study.     

Bioelectronic noses: a status report. Part I

The present state of the art to record or mimic electronically the human senses of olfaction and taste is characterized. In this part I, an introduction to our present understanding in the development of electronic and bioelectronic noses is given. Finally the natural olfactory system is described in detail.     

Green synthesis of silver nanoparticles using Zea mays and exploration of its biological applications

The biosynthesis of silver nanoparticles (AgNPs) has been proved to be a cost effective and environmental friendly approach toward chemical and physical methods. In the present study, biosynthesis of AgNPs was carried out using aqueous extract of Zea mays (Zm) husk. The initial colour change from golden yellow to orange was observed between 410 and 450 nm which confirmed the synthesis of AgNPs. Also, dynamic light scattering‐particle size analysis confirmed the average size to be 113 nm and zeta potential value of −28 kV. The morphology of synthesised Zm AgNPs displayed flower‐shaped structure, X‐ray diffraction pattern revealed the strongest peaks at 2θ = 38.6° and 64° which proved that the nanoparticle has the face centred crystalline structure. The Fourier transform infrared spectroscopy results showed strong absorption bands at 1394.53, 2980.02 and 2980.02 cm⁻¹ due to the presence of alkynes, carboxylic acids, alcoholic and phenolic groups. The maximum zone of inhibition was observed against Salmonella typhi (22 mm) and Candida albicans (18 mm). The synthesised nanoparticles exhibited more free radical scavenging activity than the aqueous plant extract. This is the first report on the synthesis of AgNP from Zm husk, delivers the efficient and stable Zm AgNPs through simple feasible approach toward green biotechnology.Inspec keywords: silver, nanoparticles, nanofabrication, light scattering, particle size, X‐ray diffraction, crystal structure, Fourier transform infrared spectra, absorption coefficients, free radicalsOther keywords: green synthesis, silver nanoparticles, biosynthesis, environmental friendly approach, aqueous extract, Zea mays husk, colour change, golden yellow, dynamic light scattering‐particle size analysis, average size, zeta potential value, flower‐shaped structure, X‐ray diffraction pattern, face centred crystalline structure, Fourier transform infrared spectroscopy, absorption bands, alkynes, carboxylic acids, alcoholic groups, phenolic groups, Salmonella typhi, Candida albicans, free radical scavenging activity, aqueous plant extraction, green biotechnology, size 113 nm, wavelength 410 nm to 450 nm     

Using split screens to combine maps and images for pedestrian navigation

Studies in the field of pedestrian navigation have shown advantages of map–image combinations. While in a previous work, the map view was either replaced with an image view in predefined situations, or the user was required to manually switch between both views, we suggest to use a split screen displaying maps and images at the same time. We developed two variants, one employing panoramic images aligned to the mobile device's orientation and the other using simple photographs, and we evaluated both against manual switching in a field study. While none of the interfaces outperformed the other, results indicate advantages of panoramic images independent of manual switching or the split screen.     

Reducing verification effort in component-based software engineering through built-in testing

Today component- and service-based technologies play a central role in many aspects of enterprise computing. However, although the technologies used to define, implement, and assemble components have improved significantly over recent years, techniques for verifying systems created from them have changed very little. The correctness and reliability of component-based systems are still usually checked using the traditional testing techniques that were in use before components and services became widespread, and the associated costs and overheads still remain high. This paper presents an approach that addresses this problem by making the system verification process more component-oriented. Based on the notion of built-in tests (BIT)—tests that are packaged and distributed with prefabricated, off-the-shelf components—the approach partially automates the testing process, thereby reducing the level of effort needed to establish the acceptability of the system. The approach consists of a method that defines how components should be written to support and make use of run-time tests, and a resource-aware infrastructure that arranges for tests to be executed when they have a minimal impact on the delivery of system services. After providing an introduction to the principles behind component-based verification and explaining the main features of the approach and its supporting infrastructure, we show by means of a case study how it can reduce system verification effort.     

Self-organization of unattended wireless acoustic sensor networks for ground target tracking

A distributed, self-organization algorithm for ground target tracking using unattended acoustic sensor network is developed. Instead of using microphone arrays, each sensor node in the sensor network uses only a single microphone as its sensing device. This design can greatly reduce the size and cost of each sensor node and allow more flexible deployment of the sensor network. The self-organization algorithm presented in this paper can dynamically select proper sensor nodes to form the localization sensor groups that can work as a virtual microphone array to perform energy efficient target localization and tracking. To achieve this, we use a time-delay based bearing estimation plus triangulation for source localization in the sensor network. Major error sources of the localization method like time delay estimation, bearing calculation and triangulation are analyzed and sensor selection criteria are developed. Based on these criteria and neighborhood information of each sensor node, a distributed self-organization algorithm is developed. Simulation results show the effectiveness of the proposed algorithm.