Nanoscale biofilm modification-method concerning a myoglobin/11-MUA bilayers for bioelectronic device

We developed surface modification tools for the fabrication of a bioelectronic device which consists of a myoglobin monolayer self-assembled on an 11-MUA layer. To utilize a single protein as the active element, it was necessary to reduce protein aggregation on the protein layer in the nanobio electronic device, which was developed in our previous study and shown to display basic biomemory functions. Here, the reduction of myoglobin aggregation was accomplished by using 3-(3-cholamidopropyl) dimethylammonio-11-propanesulfonate (CHAPS) to fabricate a well-defined protein layer on the bioelectronic device. We investigated two different surface modification methods for making well oriented biofilm. The effects of CHAPS on the formation of a myoglobin layer self-assembled on an 11-MUA layer were examined by atomic force microscopy and Raman spectroscopy. The size of the myoglobin aggregates was reduced from 200-250 nm to 10-40 nm depending on treatment method. The sustaining redox property of the CHAPS treated myoglobin layer was examined using cyclic voltammetry. Using these techniques, we found that after surfactant CHAPS treatment, protein aggregation was dramatically reduced and the protein layer still maintained its inherent electrochemical properties.     

Utilisation of modified atmosphere packaging to extend the shelf life of Khalas fresh dates

Completely matured tamr stage dates are widely available and consumed throughout the year. However, for some date varieties, the earlier khalal stage crunchy fruit is considered a premium product. This work examines the use of modified atmosphere packaging to extend the shelf life of khalal dates under refrigerated conditions. Modified atmosphere packaging with 10% or 20% CO₂ in air was successful in reducing the rate of the ripening processes while control‐packaged dates showed signs of ripening development such as significant weight loss and darkening in date colour (identified visually and as low lactic acid bacteria measurements at 18 and 27 days after packaging), similar to that observed in tamr stage fruit.     

Backtracking-Based Instruction Scheduling to Fill Branch Delay Slots

Conventional schedulers schedule operations in dependence order and never revisit or undo a scheduling decision on any operation. In contrast, backtracking schedulers may unschedule operations and can often generate better schedules. This paper develops and evaluates the backtracking approach to fill branch delay slots. We first present the structure of a generic backtracking scheduling algorithm and prove that it terminates. We then describe two more aggressive backtracking schedulers and evaluate their effectiveness. We conclude that aggressive backtracking-based instruction schedulers can effectively improve schedule quality by eliminating branch delay slots with a small amount of additional computation.     

Discrete fractional Fourier transform based on the eigenvectors of tridiagonal and nearly tridiagonal matrices

The recent emergence of the discrete fractional Fourier transform (DFRFT) has caused a revived interest in the eigenanalysis of the discrete Fourier transform (DFT) matrix F with the objective of generating orthonormal Hermite–Gaussian-like eigenvectors. The Grünbaum tridiagonal matrix T—which commutes with matrix F—has only one repeated eigenvalue with multiplicity two and simple remaining eigenvalues. A detailed eigendecomposition of matrix T is performed with the objective of deriving two orthonormal eigenvectors—common to both the F and T matrices—pertaining to the repeated eigenvalue of T. The nearly tridiagonal matrix S first introduced by Dickinson and Steiglitz and later studied by Candan et al.—which commutes with matrix F—is rigorously proved to reduce to a 2×2 block diagonal form by means of a similarity transformation defined in terms of an involutary matrix P. Moreover explicit expressions are derived for the elements of the two tridiagonal submatrices forming the two diagonal blocks in order to circumvent the need for performing two matrix multiplications. Although matrix T has the merit of being tridiagonal and does not need the tridiagonalization step as matrix S, the simulation results show that the eigenvectors of matrix S better approximate samples of the Hermite–Gaussian functions than those of matrix T and moreover they have a shorter computation time due to the block diagonalization result. Consequently they can serve as a better basis for developing the DFRFT.     

Schottky barrier effect of ZnO modified methyl glycol thin films for detection of hydrogen sulfide gas

Highly nanocrystalline ZnO modified methyl glycol thin films have been deposited on a p-type silicon substrate via the sol–gel spin coating manner. The morphology of the as-deposited film was scrutinized using scanning electron microscopy. I–V characteristics of the as-prepared ZnO film under vacuum and in open air were monitored. The results showed that the ZnO films have a barrier height of 0.38 eV under vacuum and 0.62 eV in open air. The Schottky barrier height between ZnO grains was determined for different reducing gases. The ZnO film showed high sensitivity to H₂S gas compared with other reducing gases due to the reduction of barrier height between ZnO grains. The as-prepared ZnO film was annealed at four different temperatures. X-ray diffraction manifested that the wurtzite hexagonal structure of ZnO deviated from ideality at annealing temperature greater than 650 °C. The barrier height of ZnO film decreased due to the increase of annealing temperature up to 650 °C and then decreased. The results also confirmed that the change of barrier height strongly affected the sensitivity of ZnO film.     

Global Search Method for Locating General Slip Surface Using Monte Carlo Techniques

Searching for the critical slip surface and the lowest factor of safety in slope stability analysis can be achieved by means of optimization techniques. A new search procedure in generating kinematically admissible slip surfaces has been introduced in this paper. Such a procedure is based, mainly, on the Monte Carlo methods, where both the critical global slip surface as well as its associated factor of safety is determined. Several practical examples, of known minimum factor of safety and its associated slip surface, have been used to demonstrate the efficiency and capability of the proposed method. The method is intended to be robust and effective to solve problems that involve extremely complicated slope geometry. It is as powerful as any other powerful optimization methods.     

Influence of Clay Lens on Migration of Light Nonaqueous Phase Liquid in Unsaturated Zone

This study concerns the control of movement of light nonaqueous phase liquid (LNAPL) in unsaturated zone in the presence of relatively low permeability clay lens. A two-dimensional, finite-difference numerical model for the simultaneous movement of LNAPL and water through the unsaturated zone of the soil has been developed. The system is a three fluid phase system (water, LNAPL, and air) but in the derivation of the model, air was treated as an immobile phase at constant atmospheric pressure. The flow equations for LNAPL and water were cast in terms of the wetting and non-wetting fluid pressure heads, respectively. The finite-difference equations were solved implicitly with explicitly scheme using Newton-Raphson iteration with Taylor series expansion to treat nonlinearity. A physical model to represent the infiltration of kerosene above the clay lens was constructed. The numerical results were compared with those observed experimentally. The results of all tests showed that the presence of clay lens controls the vertical movement of LNAPL in heterogeneous porous medium.     

Investigation of Efficiency Deterioration Causes in Process Centrifugal Compressor Operation

The high operating efficiency of centrifugal compressor is a basic requirement to maintain the gas productivity and machine availability. However, there are several factors influencing the stage efficiency in the operating environment leading to a deterioration in the compressor performance in addition to its impact on the mechanical integrity of the internal components. These variables can be classified into three main groups which are suction parameters variation, flow profile distortion, and compressor component damage. The determination of the root cause will help for a proper maintenance plan and to reduce the machine downtime. Hence, this paper will introduce a new approach to identify the inefficient compressor operation causes based on the available operation data. The investigated case is a three-stage gas transport centrifugal compressor driven by 2.9 MW two-shaft gas turbine. The outcomes from the conducted optimisation are compared with the measured discharge parameters and the findings from the internal inspection observation to emphasize the outcomes from the derived approach.