Knowledge-based artificial neural network model to predict the properties of alpha+ beta titanium alloys

In view of emerging applications of alpha+beta titanium alloys in aerospace and defense, we have aimed to develop a Back propagation neural network (BPNN) model capable of predicting the properties of these alloys as functions of alloy composition and/or thermomechanical processing parameters. The optimized BPNN model architecture was based on the sigmoid transfer function and has one hidden layer with ten nodes. The BPNN model showed excellent predictability of five properties: Tensile strength (r: 0.96), yield strength (r: 0.93), beta transus (r: 0.96), specific heat capacity (r: 1.00) and density (r: 0.99). The developed BPNN model was in agreement with the experimental data in demonstrating the individual effects of alloying elements in modulating the above properties. This model can serve as the platform for the design and development of new alpha+beta titanium alloys in order to attain desired strength, density and specific heat capacity.

     

Effect of Tio2 Nanoparticles on the Antibacterial and Physical Properties of Low-Density Polyethylene Film

In this study, TiO₂ nanoparticles were incorporated into low-density polyethylene by melt blending. Morphological properties and dispersion behavior of TiO₂ nanocomposite were characterized through field emission scanning electron microscope, X-ray diffraction, and Fourier transform infrared spectroscopy. Thermal stability of the nanocomposites was determined by thermogravimetric analysis. Moreover, the mechanical properties of nanocomposites were determined. Antimicrobial activity of TiO₂ nanocomposites was investigated by in vitro test. Dispersion of the nanoparticles was good in nanocomposites_. According to thermogravimetric analysis, incorporation of TiO₂ nanoparticles into low-density polyethylene enhanced the thermal stability. Mechanical properties of nanocomposites were improved by TiO₂ nanoparticles. Results showed that the antibacterial effect of low-density polyethylene –TiO₂ nanocomposite was significantly enhanced by TiO₂nanoparticles (p?2 nanoparticles not only can improve the properties of low-density polyethylene but they also have the potential to be used as an active food packaging film.     

Synthesis,Characterization and Antibacterial Properties of Nano-Porous Zn3(BTC)2·12H2O upon Silk Yarn Under Ultrasound Irradiation

A porous coordination polymer, Zn₃(BTC)₂·12H₂O (Zn-BTC) upon silk yarn, has been synthesized under ultrasound irradiation of identical reaction mixtures of Zn(II) and H₃BTC (BTC = 1,3,5-benzenetricarboxylate). Effects of temperature, sequential dipping steps and sonication on the growth of Zn-BTC upon silk yarn were investigated. These systems depicted a decrease in the particles size accompanying a decrease in the sequential dipping steps. Results showed a decrease in the particles size as decreasing frequency of ultrasound irradiation. The antimicrobial activity of Zn-BTC upon fiber was tested against the Gram positive strain Micrococcus sp. and Gram negative bacterial strain Escherichia coli. The samples were characterized with X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy spectra and scanning electron microscopy. XRPD analyses indicated that the prepared Zn-BTC nanostructures on silk fibers were crystalline.     

A macro-level decision analysis of wind power as a solution for sustainable energy in the USA

This study aims to quantify the socio-economic and environmental impacts of producing electricity by wind power plants for the US electricity mix. To accomplish this goal, all direct and supply chain-related impacts of different onshore and offshore wind turbines are quantified using a hybrid economic input-output-based triple bottom line (TBL) life cycle assessment model. Furthermore, considering TBL sustainability implications of each onshore and offshore wind energy technology, a multi-criteria decision-making tool which is coupled with Monte Carlo simulation is utilised to find the optimal choice of onshore and offshore wind energy. The analysis results indicate that V90-3.0 MW wind turbines have lower impacts than V80-3.0 MW for both socio-economic and environmental indicators. The Monte Carlo simulation results reveal that when environmental issues are more important than socio-economic impacts, V90-3.0 MW offshore is selected among the alternatives.     

A Generic Framework for Supporting Internet Services to Achieve Customer Value Creation

This paper discusses the current trends within the software industry that have affected the evolution of software support and its move to the Internet. Accordingly, it proposes a scheme for an Internet support framework within the software industry, and analyses the specific elements required for building and implementing such a system. The framework leverages and extends on strategic analysis discussed by Rayport and Viokla [1]. The evolution of ‘live’ support to Internet services emulates the evolution from the Physical Value Chain (PVC) to the Virtual Value Chain (VVC) discussed by them. In particular, the benefits of this proposed scheme to both the customer and the organisation are outlined.     

Homoacetogenesis during hydrogen production by mixed cultures dark fermentation: Unresolved challenge

This paper is a comprehensive review of H₂ consumption during anaerobic mixed culture H₂ dark fermentation with a focus on homoacetogenesis. Homoacetogenesis consumed from 11% to 43% of the H₂ yield in single and repeated batch fermentations, respectively. However, its quantification and extent during continuous fermentation are still not well understood. Models incorporating thermodynamic and kinetic controls are required to provide insight into the dynamic of homoacetogenesis during H₂ dark fermentation. Currently, no adequate method exists to eliminate homoacetogenesis because it does not depend on the culture's source, pre-treatment, substrate, type of reactor, or operation conditions. Controlling CO₂ concentrations during dark fermentation needs further investigation as a potential strategy towards controlling homoacetogenesis. Incorporating radioactive labeling technique in H₂ fermentation research could provide information on simultaneous production and consumption of H₂ during dark fermentation. Genetic studies investigating blocking H₂ consuming pathways and enhancing H₂ evolving hydrogenases are suggested towards controlling homoacetogenesis during dark fermentation.     

Development of optimal water supply plan using integrated fuzzy Delphi and fuzzy ELECTRE III methods—Case study of the Gamasiab basin

This paper presents a novel method for the development of an optimal water supply plan showcased using data from the Gamasiab basin, located in Kermanshah province, Iran, concerning new dams that are being constructed in this semi-arid region. In this paper, a new group multi-criteria decision-making (MCDM) plan is proposed by combining two MCDM methods based on the fuzzy Delphi and fuzzy ELECTRE III methods that convert the experts' opinions to triangular fuzzy numbers based on the level of uncertainty associated with various quantitative and qualitative criteria. Considering the opinions of four non-stakeholder experts and data analysis using the fuzzy Delphi method, the criteria were evaluated. Then, by analysing the results using the fuzzy ELECTRE III method, the final ranking of scenarios is obtained. A sensitivity analysis was conducted to assess the effect of uncertainty on the performance of the decision-making system in scenarios ranking. The total expense, flood control, reservoir capacity and diversion and water transfer played a significant role in selecting the optimal scenario. Additionally, a hydrologic model was developed to evaluate the performance of the optimal scenario in terms of qualitative criteria. The data indicated that there was a good agreement between the results obtained from the hydrological model and the scenario ranking by the employed method. Altogether, a comparison of the proposed method with other MCDM methods, including fuzzy analytic hierarchy process and fuzzy technique for order preference by simulation of ideal solution, indicated that the results of the employed method matched more closely to the local experts' opinion.     

System Identification of Base-Isolated Building using Seismic Response Data

Due to the complex nature of the excitation, and the inherent dynamics characteristics of restoring force of the base isolation systems, the response of base-isolated structures subject to strong earthquakes often experiences excursion into the inelastic range. Therefore, in designing base-isolated structures, the nonlinear hysteretic restoring force model of the base isolation system is frequently used to predict structural response and to evaluate structural safety. In this paper, the prediction error method system identification technique is used in conjunction with nonlinear state-space models for identification of a base-isolated structure. Using a variety of nonlinear restoring force models and bidirectional recorded seismic responses, several identification runs are conducted to evaluate the accuracy of the selected models. Several nonlinear restoring force models are utilized for the base-isolation system, including a multiple shear spring (MSS) model. Among all models used, results indicate that the trilinear hysteretic MSS model closely matches the actual hysteretic restoring force profile and time histories obtained directly from the observed data.     

Scenario-based quasi-static task mapping and scheduling for temperature-efficient MPSoC design under process variation

Nowadays, employing the worst case analysis is the most common approach to provide unified static task mapping–scheduling plans on MPSoCs. Since the whole design space nor a subset of design space are not explored in the worst case methods, these approaches may fail to achieve efficient performance yield. In this paper, we present a temperature-aware quasi-static task mapping–scheduling framework under process variation for hard real-time and periodic systems on MPSoCs. By employing the stochastic optimization and scenario-based approaches, we explore a few representative scenarios in the whole design space of the chip using the probability density function of the problem random variables. Then, we obtain a compact set of near optimal mapping–scheduling of real-time tasks which targets performance-yield maximization and minimization of the expected values of peak temperature. Consequently, considering different chip parameter configurations, we construct the plan set as the solutions that attain the best variation-aware task mapping–scheduling that satisfy the deadline and minimize the temperature. This plan set can readily look up at run time by the system scheduler of the chip to find the proper plan of the tasks based on the run-time parameters. The experimental results demonstrate significant improvements in performance-yield and peak temperature for almost all of the test cases off homogenous and heterogeneous MPSoCs.     

Diverting Electron Fluxes to Hydrogen in Mixed Anaerobic Communities Fed with Glucose and Unsaturated C18 Long Chain Fatty Acids

Hydrogen (H2) production was maximized and methane (CH4) formation was minimized in a mixed anaerobic culture which was maintained at 21°C and fed glucose plus unsaturated long chain fatty acids (LCFAs). The initial pH in the batch reactors was 7.8±0.2. The two LCFAs under consideration included linoleic acid (LA) (two C=C bonds) and oleic acid (OA) (one C=C bond). Hydrogen production was observed when glucose was injected on Day 0 and again after Day 4. The H2 yield in cultures fed LA was less than those receiving OA. The H2 yield reached a maximum of approximately 1.1?mol?H2?mol?1 glucose when the LA level was 2,000?mg?L?1. In the case of OA, a maximum yield of 1.3?mol?H2?mol?1 glucose was attained with 2,000?mg?L?1. The inhibition caused by the addition of LA or OA diverted a fraction of electrons toward proton reduction. Under maximum H2 production conditions in the LA fed cultures the acetate production pathway was repressed, while in cultures fed OA the acetate pathway was dominant. The amount of CH4 produced decreased with increasing H2 production and the major volatile fatty acids detected were acetate, propionate and butyrate. Small quantities of formate were detected only in cultures fed LA after the first glucose injection. As the LCFA concentration increased, the initial glucose degradation rate decreased.