Optimization of waste quail eggshells as biocomposites for polyaniline in ammonia gas detection

A simple, cost-effective, and novel chemical sensor for ammonia (NH₃) gas detection was developed from polyaniline (PANI)/quail eggshell (QES) composites. QES is a natural waste enriched in calcium carbonate. In this work, pure PANI was synthesized from chemical oxidation method and PANI/QES composites were prepared from physical mixing of QES with the synthesized PANI at different mass ratio. A series of complementary techniques including Fourier transform infrared and ultraviolet-visible spectrometers, scanning electron microscope with energy dispersive detection coupled with mapping, thermogravimetric analysis, and X-ray diffractometer were used to characterize the physicochemical and textural properties of the biocomposites. From the results, PANI/QES composite with a mass ratio of 1 exhibited the lowest NH₃ detection limit of 5.24 ppm with a linear correlation coefficient (R²) of close to unity (0.9932) between the signal and NH₃ gas concentration. As a whole, the PANI/QES biocomposites synthesized from this work exhibited excellent selectivity toward NH₃ gas even in the presence of other gas impurities, such as acetone, ethanol, and hexane. For the sensor reusability, the PANI/QES biocomposites can be reused in the application of NH₃ gas detection for at least 4 cycles.     

Non-Intrusive Monitoring of Everyday Behavioral Activities in an Indoor Environment

A non-intrusive design for monitoring everyday activities of an elderly person is presented. The proposed system is intended to be used in the bedroom, allowing the elders to stay at home in a safe environment. The required hardware design is simple in structure and cost effective. The sensor design is implemented by using capacitive sensors and an Arduino microcontroller unit. And a real time graphical user interface is implemented to monitor the elderly person. The performance analysis shows that the sensor design is able to differentiate between a human body and a house pet.     

Multi-User Ultra-Wide Band Communication System Based on Modified Gegenbauer and Hermite Functions

In this paper a multi-user communication system based on ultra-wide band (UWB) technology is studied. UWB uses very short pulses, so that the spectrum of the emitted signals may spread over several GHz. In order to implement multi-user communication, the emitted signal must be modulated. One modulation scheme for UWB communications is to use analog waveforms to modulate the data. In this study, orthogonal waveforms called modified Gegenbauer functions are introduced as basis functions for the pulse shape and compared to the previously proposed modified Hermite functions. It is shown that Gegenbauer functions offer better performance for multi-user UWB communications. Fouzia Elbahhar was born in 1975. She received the M.S. and Ph.D. degrees from the University of Valenciennes (France) in 2000 and 2004, respectively. She is actually employed as Research Asistant at this university. She is especially involved in Ultra Wide Band technology. Her primary interest is in systems dedicated to land transportation for communications, like vehicle to vehicle telecommunication. Atika Rivenq-Menhaj was born in 1970. She received her Diploma of Engineering and the M.S. degree in 1993 and then her Ph.D. degree in 1996, from the University of Valenciennes (France). She actually is Assistant Professor in electronics at this university. Her primary interest is in signal processing applied to intelligent transportation systems and telecommunication systems. Jean-Michel Rouvaen was born in 1947. He received his M.S. degree in 1968 and his Ph.D. degree in 1971, from the University of Valenciennes (France). He is now Professor of electronics at ENSIAME, an engineering school of university of Valenciennes. His primary interests are in signal processing, nonlinear phenomena and telecommunications.     

A new approach to mixing techniques for enhanced performance in automated sample preparation

In the automation of sample dilution or derivatization, the performance of the mixing technique employed when adding solvents or reagents to samples is critical. This paper presents a newly developed mixing method, based on conventional aspiration and dispensing of liquid techniques, but which considerably improves the precision of mixing. The paper discusses the results of a comparison of the technique with other methods and describes the application of the technique to several different types of sample solutions, including a highly concentrated glucose solution. The mixing technique was performed on a Gilson XL Sampling Injector, with a 1/25 dilution of a paraben solution in 2 ml vials to give relative standard deviations of 0.2 to 0.3% (N =10).     

An environment for modelling and simulating communication systems: Application to a system based on a satellite backbone

The availability of good software tools is vital to simulation practitioners. The objective of the OSISIM project (open system integrated simulator) is to set up an environment which integrates facilities and tools to build a communication system, and to study its performance. The environment is called AMS : atelier for modelling and simulation. Using it, the network architect, i.e. the user of the atelier, can quickly construct, in a graphical environment, a concise system from models of several standard networks available in a specific library, and execute the system in an efficient manner. Starting with an outline of the components of the atelier, we describe the AMS prototype, and the internal structure of basic models to be included in it. Moreover, a concrete example of a communication system including a satellite backbone is provided to illustrate how AMS is used to simulate such a system.     

Mobile banking in the government-to-person payment sector for financial inclusion in Pakistan*

ABSTRACT

Whilst there have been growing interest and efforts by governments in developing countries to disburse digital government-to-person (G2P) payments to promote financial inclusion, the role of mobile banking in the receipt of social cash remains under-researched. Through an interpretive case study of the Benazir Income Support Programme (BISP) in Pakistan, this paper applies Orlikowski’s Duality of Technology that critically examines mobile banking usage by women beneficiaries and technology's effects on the institutional properties of their households. Qualitative data were collected through semi-structured interviews from participants located in Pakistan. The findings highlighted that mobile banking enabled women to receive the full amount of grants, securely and conveniently, from agents. However, mobile banking imposed human, socio-economic and technological constraints which restricted women's access to and usage of financial services that limited financial inclusion. Women were socially and politically empowered, thereby, social inclusion was transformative. This paper theoretically contributes to the Duality of Technology framework that was deterministic for women beneficiaries. The study accentuates the redesign of mobile banking to match women's capabilities, and imparting financial and digital training to them. Also, the provision of a range of financial resources to beneficiaries may steer micro-entrepreneurial activities to advance the inclusion agenda in Pakistan.     

Preparation and electroanalytical characterization of polyaniline: Polyacrylonitrile composite films

Electrically conducting composite films of polyaniline:polyacyrlonitrile (PANI:PAN) prepared with varying composition ratios of aniline mixed with a fixed amount PAN. The films of optimum thicknesses (0.10 mm) were obtained using an electrically operated automatic pressure machine. The films polymerized by oxidative polymerization using 0.1M potassium persulphate (K₂S₂O₈), undoped in 1M aqueous ammonia (NH₄OH) and doped in 1M hydrochloric acid (HCl). The conductivity of composite films was studied by keeping it in 1M HCl for different time period using 4-in-line probe DC electrical conductivity measuring instrument and the temperature dependence of DC electrical conductivity was studied using isothermal technique. The PANI:PAN composite film is used as a working electrode in an electrochemical cell. Chemically doped composite film is used as cathode (working electrode), aluminum metal foil as anode (counter electrode) and platinum foil as reference electrode. The electrolyte is of 0.05M aluminum chloride (AlCl₃) in dimethyl sulfoxide (DMSO). The voltage of the working electrode is stabilized with respect to the reference electrode and current applied between the working and counter electrode through a 9-V battery. The change in voltage versus time is plotted as the discharge curve and reversing the cell processes results in the doping of the composite films. The diffusion coefficient of the dopant ion (Cl⁻) present in the fully doped films were estimated by the galvanostatic pulse technique and found to bedifferent in different samples in the range of 10⁻¹⁶ to 10⁻¹² cm² s⁻¹. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Polyphasic characterization of Aspergillus section Flavi isolated from animal feeds in Algeria

In Algeria, little information is available on the population structure of Aspergillus section Flavi in raw materials and resultant animal feeds. A total of 172 isolates belonging to Aspergillus section Flavi were recovered from 57 animal feeds and identified on the basis of macro and micro-morphological characters, mycotoxin production and genetic relatedness. For the molecular analysis, sequencing of the calmodulin gene (CaM) and the internal transcribed spacer (ITS) regions were performed for representative isolates. Four distinct morphotypes were distinguished: Aspergillus flavus (78.5%), Aspergillus tamarii (19.2%), Aspergillus parasiticus (1.7%), and Aspergillus alliaceus (0.6%). All A. flavus isolates were of the L type and no correlation between sclerotia production and aflatoxigenicity was observed. Our results showed that 68% of the A. flavus strains produced aflatoxins B (AFB), and 72.7% were cyclopiazonic acid (CPA) producers. The three isolates of A. parasiticus were able to produce AFB and aflatoxins G but not CPA whereas, all the strains of A. tamarii produced only CPA. The obtained results revealed the presence of different species of Aspergillus section Flavi, among which were aflatoxin producers. This study provides evidence useful for considerations in aflatoxin control strategies.