Failure of Azotobacter Vinelandii to Fix Nitrogen in Soil

It was found that Azotobacter vinelandii grown in a dialyzed soil medium did not fix nitrogen and had a much lower rate of respiration than when grown in Burk's nitrogen-free medium. When para-hydroxybenzoic acid served as the added oxidizable organic carbon source in dialyzed soil medium, the azotobacter grown in it were found to be unable to fix nitrogen. On the other hand, A. vinelandii fixed nitrogen when grown in soil supplemented with glucose. It was concluded that natural conditions in the soil are not conducive to nitrogen fixation by A. vinelandii

Design and implementation of a single input fuzzy logic controller for boost converters

This paper describes the design and hardware implementation of a Single Input Fuzzy Logic Controller (SIFLC) to regulate the output voltage of a boost power converter. The proposed controller is derived from the signed distance method, which reduces a multi-input conventional Fuzzy Logic Controller (CFLC) to a single input FLC. This allows the rule table to be approximated to a one-dimensional piecewise linear control surface. A MATLAB simulation demonstrated that the performance of a boost converter is identical when subjected to the SIFLC or a CFLC. However, the SIFLC requires nearly an order of magnitude less time to execute its algorithm. Therefore the former can replace the latter with no significant degradation in performance. To validate the feasibility of the SIFLC, a 50W boost converter prototype is built. The SIFLC algorithm is implemented using an Altera FPGA. It was found that the SIFLC with asymmetrical membership functions exhibits an excellent response to load and input reference changes

FPGA implementation of a single-input fuzzy logic controller for boost converter with the absence of an external analog-to-digital converter

In this paper, the single-input fuzzy logic controller (FLC) (SIFLC) for boost converter output-voltage regulation is proposed. The SIFLC utilizes the signed distance method that reduces the multidimensional rule table to 1-D with only one input variable, i.e., distance d. The simplification allows for the control surface to be approximated by a piecewise linear. It is shown that, despite the simplicity of SIFLC, its control performance is almost equivalent to that of the conventional FLC. As a proof of concept, the SIFLC is implemented using the Altera EP2C35F672C6N field-programmable gate array (FPGA) and applied on a 50-W boost converter. The SIFLC is compared to the proportional–integral controller; the simulation and practical results indicate that SIFLC exhibits excellent performance for step load and input reference changes. Another feature of this work is the absence of an external analog-to-digital converter (ADC). Instead, a simple analog-to-digital conversion scheme is implemented using the FPGA itself. Due to the simplicity of the SIFLC algorithm and the absence of an external ADC, the overall implementation requires only 408 logic elements and five input–output pins of the FPGA. Index Terms—Boost converter

NiCo₂O₄@ZnCo₂O₄ nanomaterial for selective and fast dispersive solid phase micro-extraction of manganese and lead in water, tea and cinnamon samples followed by FAAS determination

NiCo2O4@ZnCo2O4 nanomaterial was synthesized and XRD, FTIR, FESEM, zeta potential measurements, and BET were used for characterization. It was first used as a sorbent for simultaneous dispersive solid phase micro extraction (d-SP mu E) of manganese and lead in water, tea and cinnamon. The determination of analytes was made by FAAS. The pH, elution conditions, sample volume, contact times, and effect of competing ions on the d-SP mu E of manganese and lead was examined. The optimal pH, and eluent for manganese and lead were found to be 4 and 2 mol/L hydrochloric acid (3 mL), respectively. The adsorption was carried out without vortexing and contact time for elution was only 30 s. The LOD and PFs of the d-SP mu E for manganese and lead were 1.7 mu g L-1, 16.7 for manganese and 4.0 mu g L-1, 33.3 for lead, respectively. The tolerable concentrations of interfering ions for analytes were rather high. The accuracy of d-SP mu E was confirmed with analyses of BCR-482 Lichen, TMDA-70.2 Lake water, and NIST RM 8704 Buffalo River Sediment and applying d-SP mu E to spiked sea water, wastewater, dam water, tea and cinnamon

Capturing and transacting ‘value for students’ in the Digital University: the Blockchain Educational Passport

A combination of economic, social and political factors, have impacted on universities’ core activities, their mission, identity and relationship with students, staff and stakeholders. The expectation is that universities should operate in a Triple Helix system of knowledge production characterized by dynamic trans-disciplinary links between academia, government and industry (Etzkowitz, et al, 2000), reiterated in a number of recent UK policies culminating in the Higher Education Research Act 2017 and the creation of the Office for Students as a regulatory body focusing on ‘value for money’, while also having social and civic impact (Goddard and Vallance, 2011). Cast between achieving ‘value for money’ as cost efficiency and ‘value for students’ and society, universities in the UK and Europe are struggling to achieve at times contradictory goals. It is therefore in the interest of learners, universities and employers to have a reliable, permanent and yet flexible way to acknowledge learning achievements and their impact. In addressing the need for a new and more nuanced accountability system, this paper draws from the Whitepaper 5.0 Blockchain Educational Passport: the Decentralised Learning Ledger (DLL) to suggest ways in which universities, employers and learners can gain from each other’s contribution. By using Blockchain as an immutable ledger of learning gains, the whitepaper contributes to the University of Northampton’s Future Focused revised strategic goal of ‘working closely with technology industry leaders ... [to] implement innovative sector leading solutions’ (UoN, 2017)