Structural,Thermal and Luminescence Study of Ceria Nanocrystals Dispersed in Silica Matrix

Silicon - Ceria (CeO2) nanocrystals dispersed in silica were prepared by sol-gel, a very suitable method for large-scale production. The formation of cubic fluorite structure of CeO2 nanocrystals...     

Assessment of proteolysis in ultra‐high temperature milk using attenuated total reflectance–Fourier transform infrared spectroscopy

This study investigated the suitability of attenuated total reflectance–Fourier transform infrared spectroscopy (ATR‐FTIR) as an alternative technique to assess proteolysis in ultra‐high temperature (UHT) milk. Commercial UHT milk samples were stored (5 and 30 °C) and analysed for four months. Milk samples were treated with acetic acid and trichloroacetic acid to obtain milk extracts containing peptides. The concentrated extracts were subjected to ATR‐FTIR, and the spectrum was obtained. Results were compared with techniques like high‐performance liquid chromatography, fluorescamine and 2,4,6‐trinitrobenzenesulphonic acid. The present study indicated that ATR‐FTIR‐based method can be used as an alternative method for assessing proteolysis in UHT milk.     

Tuning of structural,optical, and magnetic properties of ultrathin and thin ZnO nanowire arrays for nano device applications

One-dimensional (1-D) ultrathin (15 nm) and thin (100 nm) aligned 1-D (0001) and (0001¯) oriented zinc oxide (ZnO) nanowire (NW) arrays were fabricated on copper substrates by one-step electrochemical deposition inside the pores of polycarbonate membranes. The aspect ratio dependence of the compressive stress because of the lattice mismatch between NW array/substrate interface and crystallite size variations is investigated. X-ray diffraction results show that the polycrystalline ZnO NWs have a wurtzite structure with a = 3.24 Å, c = 5.20 Å, and [002] elongation. HRTEM and SAED pattern confirmed the polycrystalline nature of ultrathin ZnO NWs and lattice spacing of 0.58 nm. The crystallite size and compressive stress in as-grown 15- and 100-nm wires are 12.8 nm and 0.2248 GPa and 22.8 nm and 0.1359 GPa, which changed to 16.1 nm and 1.0307 GPa and 47.5 nm and 1.1677 GPa after annealing at 873 K in ultrahigh vacuum (UHV), respectively. Micro-Raman spectroscopy showed that the increase in E₂ (high) phonon frequency corresponds to much higher compressive stresses in ultrathin NW arrays. The minimum-maximum magnetization magnitude for the as-grown ultrathin and thin NW arrays are approximately 8.45 × 10⁻³ to 8.10 × 10⁻³ emu/g and approximately 2.22 × 10⁻⁷ to 2.190 × 10⁻⁷ emu/g, respectively. The magnetization in 15-nm NW arrays is about 4 orders of magnitude higher than that in the 100 nm arrays but can be reduced greatly by the UHV annealing. The origin of ultrathin and thin NW array ferromagnetism may be the exchange interactions between localized electron spin moments resulting from oxygen vacancies at the surfaces of ZnO NWs. The n-type conductivity of 15-nm NW array is higher by about a factor of 2 compared to that of the 100-nm ZnO NWs, and both can be greatly enhanced by UHV annealing. The ability to tune the stresses and the structural and relative occupancies of ZnO NWs in a wide range by annealing has important implications for the design of advanced photonic, electronic, and magneto-optic nano devices.     

Urea biosensors

A biosensor is an analytical tool that comprises two essential components—an immobilized biocomponent, in intimate contact with a transducer that converts a biological signal into a measurable electrical signal. This review summarizes the studies carried on the development of biosensors for the analysis of urea in different fields of application, the various techniques of immobilization of urease enzyme, the stability and response time characteristics and the transducers used for biosensor development such as pH electrodes, ammonia gas sensing electrodes, ammonium ion-selective electrodes, optical, conductometric and amperometric transducers. Underlying the importance of this study is the fact that urea is toxic above certain concentrations and its continuous real time monitoring in clinical, environmental and food related environments is of utmost interest. The conventional analytical techniques used, although precise, are time consuming and mostly laboratory bound whereas biosensors have the advantages of ease of use, portability and the ability to furnish real time signals.     

Influence of the forming angle in cross wedge rolling on the multi-directional forging of crankshafts

In each industrial process for the production of crankshafts a low energy demand and a fast processing time are required. Crankshafts have a very complex geometry and are forged with a high percentage of flash compared to other forging parts. Recent research showed the feasibility of a flashless forging of crankshafts. One way to forge a flashless crankshaft within three steps is to use cross wedge rolling, multi-directional forging and final forging. This paper presents the investigation results regarding the influence of the forming angle α in cross wedge rolling on different parameters at multi-directional forging. First, the state of the art is presented. As a basis for the investigations the process development and tool design of cross wedge rolling and multi-directional forging are described. Afterwards the paper’s results regarding the influence of the forming angle α on flash generation, billet temperatures, forming degree, forming forces and effective strain will be presented as a parameter study. Generally, flash is generated because a rotation-symmetric billet is forced into an asymmetric movement. The influence of an increasing forming angle leads to a higher amount of flash at the bottom of the crankwebs.     

Naphthalene diimide self-assembled ribbons with high electrical conductivity and mobility without doping

The thermally activated electrical conductivity and charge transfer properties of self-assembled naphthalene diimide molecule have been studied with N,N’di(hexadecyl)naphthalene tetracarboxylic diimide (HD-NDI) derivative. The self-assembly of HD-NDI has been resulted in one-dimensional large micron-size ribbons. The aggregate formation and self-assembling property have been extensively studied by absorption, fluorescence and X-ray diffraction analysis. Absorption and fluorescence measurements were taken in variety of solvents in fresh and aged samples, and the study suggested J-type aggregation for self-assembly formation. The electrical conductivity of self-assembled HD-NDI material was measured as a function of temperature where the conductivity increased with temperature and the highest conductivity (1 × 10^?5 S/cm) was obtained at 250 °C. SEM images clearly show the formation of ribbons of micron size. Further the electron transport property of HD-NDI was also evaluated by SCLC method at room temperature by fabricating electron-only devices with annealing the film at ~ 200 °C. HD-NDI shows excellent electron mobility (1.8 × 10^?3 cm² V^?1 s^?1) because of effective channel formation due to self-assembly of HD-NDI molecules, and this material may find potential application in variety of electronic devices.     

Economic Analysis of Recreation Access at a Lake Facing Water Crisis due to Municipal Water Demand

Water Resources Management - Droughts and water demand for competing uses such as municipal supply, nature-based recreation, and fisheries have added challenges in lake management. Sustaining the...     

Effect of thermal and non-thermal processing on antioxidant potential of cowpea seeds

Legumes are a good source of bioactive components, besides being nutrient dense. These components have antioxidant properties and have a protective role against free radicals. Legumes like cowpeas are usually consumed after certain processing, so the present study was intended to assess antioxidant property of selected four cultivars of cowpea after going through various thermal (autoclaving, microwave, boiling, and roasting) and non-thermal (soaking and fermentation) processings. Thermal processing reduced total phenolic content (TPC), total flavonoid content (TFC), and ferric reducing antioxidant power (FRAP) in all cultivars with respect to antioxidant activity of raw cultivars, while DPPH scavenging activity increased after all thermal treatments excluding few thermal processings. Non-thermal processing revealed increase in TPC, DPPH scavenging activity, and FRAP values, while TFC content showed a decreasing trend. A moderately high correlation between TPC and DPPH scavenging activity was observed in both kinds of thermal treatments indicating the role of phenolic compounds for antioxidant activity. It was concluded from the study that fermentation processing has promising effects on retention and enhancement of antioxidant activity of cowpea cultivars.     

Crossing the boundaries of safe operation: An approach for training technical skills in error management

Robust error management within the cockpit is crucial to aviation safety. Crew resource management (CRM) focuses on non-technical skills for error management but the training of technical skills for error detection and error recovery is also a potentially valuable strategy. We propose a theoretical basis for training technical skills in error management as well as a cognitively oriented technique for analysing accidents and incidents to identify specific training requirements. To evaluate the strengths and limitations of this new approach, we present a case study of its application to the F-111, a strike aircraft in the Royal Australian Air Force. This case study demonstrates that the new training approach is both feasible and useful, although an empirical validation of the approach is still necessary. In addition, the case study highlights the limitations of the current F-111 simulator for training technical skills for error detection and error recovery.

Designing teams for first-of-a-kind, complex systems using the initial phases of cognitive work analysis: case study

We present a technique for team design based on cognitive work analysis (CWA). We first develop a rationale for this technique by discussing the limitations of conventional approaches for team design in light of the special characteristics of first-of-a-kind, complex systems. We then introduce the CWA-based technique for team design and provide a case study of how we used this technique to design a team for a first-of-a-kind, complex military system during the early stages of its development. In addition to illustrating the CWA-based technique by example, the case study allows us to evaluate the technique. This case study demonstrates that the CWA-based technique for team design is both feasible and useful, although empirical validation of the technique is still necessary. Applications of this work include the design of teams for first-of-a-kind, complex systems in military, medical, and industrial domains.