Fabrication of carbon paste electrode containing a new inorganic–organic hybrid based on [SiW12O40]4− polyoxoanion and Nile blue and its electrocatalytic activity toward nitrite reduction

In this study, a new inorganic–organic hybrid compound consisting of a Keggin type polyoxometalate, H4SiW12O40 (SiW12), and Nile blue (NB) was synthesized and characterized. The (NB)2H2SiW12O40 (NB2SiW12) hybrid compound was characterized by Fourier transform infrared (FT-IR), elemental (CHNS) analysis, UV–Vis and thermogravimetry techniques, and used as a bulk modifier to fabricate a chemically modified carbon paste electrode (CPE) by direct mixing. The electrochemical behavior of the newly NB2SiW12 composite CPE was analyzed by cyclic voltammetry, and the electrode was applied for nitrite reduction, exhibiting high electrocatalytic activity. Determination of nitrite by fixed potential amperometry was done under various experimental conditions and, at the optimum conditions, the linear response ranged from 5 to 1200 μM with a high sensitivity of and a low detection limit. The electrode has the remarkable advantage of surface renewal owing to bulk modification, as well as simple preparation, good mechanical and chemical stability and reproducibility. No noticeable interferences from other ionic species usually found in natural water were observed. The new developed electrode has been successfully applied for detection of nitrite in real water samples

Qualitative Research in Psychology: Unsilencing the Marginalized Voices

What better way of building bridges between diverse people and communities, than through developing an understanding of their lived experiences and untold stories? Qualitative methods not only provide a voice to the silenced marginalized individuals that are often overlooked in research since they do not fit the paradigm, but qualitative approaches also provide a platform for social justice, multiculturalism and collaborative community based action research. In the recent years, there has been a paradigm shift in the field of psychology and researchers are moving from more traditional quantitative methods towards qualitative ways for analysing the data (Ponterotto, 2005). Quantitative research in psychology was originally derived for the “majority white male” population and many of the quantitative measures in psychology did not and to an extent still do not take into account minority individuals. Due to the depth and richness of context provided by the qualitative data and its discovery oriented approach (Hill, 1997), qualitative research can help provide a voice to the marginalized groups (Ponterotto, 2010). Thus, as a part of this symposium, we will be presenting on the qualitative approaches and theoretical background of Consensual Qualitative Research (CQR), Grounded Theory, Phenomenology, Narrative Analysis, Action Research and Arts - Based Research. We will conclude with examples of qualitative studies using the above mentioned methods in psychology and a discussion of how these different approaches could be utilized for research focusing on individuals with a minority status. Lastly, we will impart future implications for using qualitative methods as a way of bridging the gap between psychological research and multiculturalism in order to facilitate advocacy, social justice and empowerment

Design and application of a flow cell for carbon-film based electrochemical enzyme biosensors

A flow cell has been designed for use with an electrochemical enzyme biosensor, based on low-cost carbon-film electrodes. Three types of mediators were used: cobalt and copper hexacyanoferrates and poly(neutral red) (PNR), covered with glucose oxidase (GOx) immobilised by cross-linking with glutaraldehyde in the presence of bovine serum albumin or inside a oxysilane sol-gel network. Mixtures of sol-gel precursors were made from 3-aminopropyl-triethoxysilane (APTOS) together with methyltrimethoxysilane (MTMOS), methyltriethoxysilane (MTEOS), tetraethyloxysilane (TEOS) or 3-glycidoxypropyl-trimethoxysilane (GOPMOS), and the best chosen for encapsulation. Optimisation in batch mode, using amperometric detection at fixed potential, showed the PNR-GOx modified carbon-film electrodes to be best for flow analysis for both glutaraldehyde and sol-gel enzyme immobilisation. Both types of enzyme electrode were tested under flow conditions and the reproducibility and stability of the biosensors were evaluated. The biosensors were used for fermentation monitoring of glucose in grape must and interference studies were also performed.http://www.sciencedirect.com/science/article/B6THP-4M0BH9Y-2/1/306f5db86217ea276bf808fb05c0288

Rare earth oxycarbonates as a material class for chemoresistive CO2 gas sensors

AbstractIn this work we compare the CO2 gas sensing properties of two new materials synthesized from rare earth hydroxide (La(OH)3,Pr(OH)3) precursors, with the already reported ones for neodymium oxycarbonate, which was synthesized from the corresponding Nd(OH)3 precursor. In-situ XRD measurements show that by following similar thermal treatment, praseodymium hydroxide is transforming to the metal oxide while lanthanum hydroxide forms an oxycarbonate, like in the case of neodymium. The chemoresistive effects we found for the lanthanum oxycarbonate were even higher than the ones recorded for the neodymium oxycarbonate; for the praseodymium metal oxide we could not find any CO2 sensitivity. Accordingly, we think that the condition for CO2 sensing is the formation of the rare earth oxycarbonate

CO2 sensing with chemoresistive Nd2O2CO3 sensors - Operando insights

AbstractIn this work the sensing of Nd2O2CO3-based chemoresistive CO2 sensor was investigated combining DRIFT and DC-resistance measurements. Besides the already reported effect of CO2 exposure, we found that exposure to CO determines comparable effects and that the presence of oxygen in the background is not important. The humidity significantly influences the response for both gases. The spectroscopic results reveal that the exposure to both CO and CO2 consumes the water-related surface species – the rooted-hydroxyls being the electrically active one – and increases the concentration of carbonates; the decrease of the rooted-hydroxyls is probably the cause of the resistance increase

Behaviours, motivations and values: Validity, reliability, and utility of novice motorcyclist' self-report in road safety research

The continuing use of self-report methods demands consideration of the validity, reliability, and utility of self-report in road safety research. This thesis assesses self-report issues with respect to four key constructs in motorcycle safety research—exposure, on-road behaviours, riding motivations, and perceived value in a sample of Australian novice motorcycle riders. In Study 1 a comprehensive set of statistical analyses was performed to test the validity and reliability of various self-report measures of riding exposure. In Study 2 and Study 3 previously untested psychometric properties of stability, content validity, and predictive validity of the Motorcycle Rider Behaviour Questionnaire and the Motorcycle Rider Motivation Questionnaire in terms of police-recorded offences and crashes as well as previously assessed factor structure, internal consistency, and predictive validity in terms of self-reported crashes were examined. In Study 4 I demonstrated the utility of a contingent valuation (CV) survey in measuring, understanding, and therefore addressing the perceived value of rider training amongst novice riders. The four studies highlight that the appropriateness of self-report depends on not only the nature of the phenomenon under study but the extent to which the factors that contribute to validity and reliability are accounted for in the design of self-report measures

TECHNOLOGY FOR ORGANIC WEED CONTROL

In recent years, crop maintenance works have become a major challenge for organic farming systems, where the application of chemical treatments is totally forbidden. The effect of weeds on crops varies according to pedoclimatic, biological or technological parameters, the resulting damages being both quantitative and qualitative. By weed control, we aim to prevent their competition in order to obtain maximum crop yields.Among the methods of thermal weed control, used as an alternative to chemical weeding, steam or hot water-based ones have been increasingly used as they provide an efficient, environmentally friendly and economical way of removing harmful plants.This paper presents a technology for the maintenance of medicinal and aromatic plant organic crops, based on the use of innovative equipment for weed thermal control by using hot water