DNA binding site characterization by means of Rényi entropy measures on nucleotide transitions.

In this work, parametric information-theory measures for the characterization of binding sites in DNA are extended with the use of transitional probabilities on the sequence. We propose the use of parametric uncertainty measures such as Rényi entropies obtained from the transition probabilities for the study of the binding sites, in addition to nucleotide frequency-based Rényi measures. Results are reported in this work comparing transition frequencies (i.e., dinucleotides) and base frequencies for Shannon and parametric Rényi entropies for a number of binding sites found in E. Coli, lambda and T7 organisms. We observe that the information provided by both approaches is not redundant. Furthermore, under the presence of noise in the binding site matrix we observe overall improved robustness of nucleotide transition-based algorithms when compared with nucleotide frequency-based method.     

Measurement of stress in multicoat systems

Mathematical relationships to calculate the stress in each layer of a multicoat system are derived. They were verified for a bi- and a trilayer acrylic/melamine system by comparing the thermal stress values determined from the derived equations with those calculated from an equation which requires the knowledge of the layers’ properties (elastic modulus, Poisson’s ratio, and glass transition temperature). Experimental procedures for coating systems unaffected and affected by multiple application and curing are described, and a few cases met in practice are presented. This study should provide a better understanding of the interactions between various layers of a multicoat system, and the damage (delamination, cracking) which might result from them. RGE Dept., P.O. Box 9300, 6800 SB Arnhem, The Netherlands.     

Performance assessment of multicriteria damage identification genetic algorithms

Damage detection methods based on model updating method have usually been developed as single objective optimization problems. However, the lack of a clear objective function in the context of real-world damage detection problems advises simultaneous optimizations of several objectives with the purpose of improving the performance of the procedure. The application of genetic algorithms for solving multiobjective optimization constitutes an emergent research area nowadays. However, their application to damage identification problems is very limited and, practically, no comparative study has been presented up to now. In this paper, some multiobjective GAs based on aggregating functions and Pareto optimality are compared.     

Ionic conductivity of a gel polymer electrolyte based on Mg(ClO4)2 and polyacrylonitrile (PAN)

Magnesium ion containing gel polymer electrolytes based on polyacrylonitrile (PAN) have been synthesized and characterized using ac impedance measurements. The electrolyte composition having the highest room temperature conductivity was found by varying the ratios propylene carbonate/ethylene carbonate (PC/EC) and PAN/Mg(ClO₄)₂. The corresponding composition was 18 mol% PAN:64 mol% EC:14 mol% PC:4 mol% Mg(ClO₄)₂. The ac conductivity measurements were carried out from room temperature upto 70 °C with blocking (stainless steel) electrodes. The room temperature conductivity is 3.2×10⁻³ S cm⁻¹ and the activation energy is 0.24 eV over the temperature range used. The high conductivity and the low activation energy of the material could possibly be due to the liquid electrolyte, Mg(ClO₄)₂ in EC/PC trapped in a matrix of PAN, as suggested by previous workers. According to dc polarization measurements, the gel electrolyte appears to be predominantly an anionic conductor.     

Demonstration of feasibility of operating a silicon ZIP detector with 20 eV threshold

100-g silicon detectors (known as “ZIPs,” Z-resolving Ionization and Phonon detectors) developed by the Cryogenic Dark Matter Search Experiment have been tested at charge bias voltages of up to 200 V/cm, significantly above their usual operating range (3–6 V/cm). Thermal gain factors in excess of 50 were observed due to the primary ionization drifting in the large applied field, with only minimal increase in phonon noise. The observed thermal gain corresponds to an intrinsic threshold of 20 eV, resulting in detectors that have direct application for use in a neutrino magnetic moment measurement based on a 40-MCi tritium source.     

Flame temperature analysis of biodiesel blends and components

Meeting sustainable energy demand with minimum environmental impact is a major area of concern in the energy sector. Alternative fuels such as biodiesel, ethanol etc. have been quite promising for fulfilling both these aspects. While biodiesel reduces emissions of CO, life cycle CO₂, SO_x, volatile organic compounds (VOC) and particulate matter (PM) significantly, the propensity for the production of NO_x is an important problem that requires extensive research. NO_x emission from a direct-injection diesel engine is mainly due to formation of thermal NO that is described by Zeldovich mechanism. Thus, studying temperature profile during biodiesel combustion can provide useful insights to the formation and destruction of NO_x. The main objective of this work is to investigate the effect of component methyl esters of biodiesel on open air flame temperature distribution and the effect of blending biodiesel with diesel and oxygenates (ethanol and methyl acetate) on open air flames. This objective was achieved by obtaining thermocouple measurements and thermal infrared imaging of local flame temperatures of wick-generated open air flames. A relationship between blend proportions and relative flame temperatures were obtained. In general, it was found that blending oxygenates such as ethanol and methyl acetate into petroleum diesel tended to increase the flame temperature in comparison with straight diesel fuel. The analyses of relative flame temperatures of different components of biodiesel were performed to evaluate the effect of unsaturation level and the hydrocarbon chain length on the flame temperature. It was found that the saturated methyl esters resulted in greater flame temperatures in comparison to unsaturated methyl esters. It was also revealed that shorter chained fatty acid methyl esters lead to higher flame temperatures as compared to its longer chained counterparts.     

Integration of a double-polysilicon emitter-base self-alignedbipolar transistor into a 0.5-μm BiCMOS technology for fast 4-MbSRAM's

The single-polysilicon non-self-aligned bipolar transistor in a 0.5-μm BiCMOS technology has been converted into a double-polysilicon emitter-base self-aligned bipolar transistor with little increase in process complexity. Improved bipolar performance in the form of smaller base resistance and base-collector capacitance, larger knee current, higher peak cutoff frequency, and shorter ECL gate delay has been demonstrated. This technology will prove useful in meeting the requirements for higher performance in fast, high-density, SRAM circuits     

Comparison of Structural Deterioration Models for Stormwater Drainage Pipes

Abstract:   Structural deterioration of pipes is the continuing reduction of load bearing capacity, which can be characterized through structural defects. Structural deterioration has been a major concern for asset managers in maintaining the required performance of stormwater drainage systems in Australia. Condition assessment using closed circuit television (CCTV) inspection is often carried out to assess the deteriorating condition of individual pipes. In this study, two models were developed using ordered probit and neural networks (NNs) techniques for predicting the structural condition of individual pipes. The predictive performances were compared using CCTV data collected for a local government authority in Melbourne, Australia. The significant input factors to the outputs of both models were also identified. The results showed that the NN model was more suitable for modeling structural deterioration than the ordered probit model. The hydraulic condition, pipe size, and pipe location were found to be significant factors for this case study.     

EVALUATION OF A COMPOSITE BASED ON HIGH-DENSITY POLYETHYLENE FILLED WITH SURFACE-TREATED HYDROXYAPATITE

Summary  Composites properties are directly related to the degree of interaction between the plastic matrix and the inorganic filler. In the present work, the improvement of the composite’s properties by means of the addition of surface-treated and untreated hydroxyapatite (STHA and HA, respectively) was studied. An ethylene-acrylic acid copolymer was melt blended with high-density polyethylene and HA (HDPE/HA/EA). A surface treatment was performed using an ethylene-acrylic acid (EA) copolymer for STHA₁ and acrylic acid (AA) for STHA₂. High-density polyethylene (HDPE) was also tested. STHA₁ and STHA₂ composites exhibited Young’s modulus values (556 and 558 MPa, respectively) 22 % higher than that of HDPE/HA (455 MPa) and 8 % higher than that of HDPE/HA/EA (520 MPa). Additionally, STHA composites showed both yield stress and strain (σ_STHA1= 23 MPa; ε_STHA1= 9 %; σ_STHA2= 22 MPa; ε_STHA2= 10 %) having a remarkably different behavior from that of the HA composites, which showed no yielding at all. TEM micrographs showed better filler dispersion when surface treatment was applied to HA. Yet, the presence of EA copolymer exhibited a poorer thermal stability. The crystallinity degree as well as the crystallization and melting temperatures showed no significant variation. Regarding in vitro evaluation, composites with HA and EA copolymer proved to have better cell adhesion at early stages. The results of the STHA composites could be attributed to the electrostatic interactions taking place between the ethylene-acrylic acid copolymer and the polar groups of the HA.     

A combinatorial approach in designing hydrophilic surfaces for solid‐phase peptide synthesis

A hydrophilic surface suitable for solid‐state peptide synthesis was developed on a solid support called a lantern. The split‐and‐mix combinatorial technique was used to prepare about 500 surfaces in a very short time. Surfaces were analyzed according to values for gel formation, percentage weight grafted, grafted copolymer composition, and number of functional groups per lantern. These values were correlated to the purity of a peptide synthesized on these surfaces. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3371–3378, 2003