Applying an intelligent model and sensitivity analysis to inspect mass transfer kinetics,shrinkage and crust color changes of deep-fat fried ostrich meat cubes

The objectives of this study were to use image analysis and artificial neural network (ANN) to predict mass transfer kinetics as well as color changes and shrinkage of deep-fat fried ostrich meat cubes. Two generalized feedforward networks were separately developed by using the operation conditions as inputs. Results based on the highest numerical quantities of the correlation coefficients between the experimental versus predicted values, showed proper fitting. Sensitivity analysis results of selected ANNs showed that among the input variables, frying temperature was the most sensitive to moisture content (MC) and fat content (FC) compared to other variables. Sensitivity analysis results of selected ANNs showed that MC and FC were the most sensitive to frying temperature compared to other input variables. Similarly, for the second ANN architecture, microwave power density was the most impressive variable having the maximum influence on both shrinkage percentage and color changes.     

A Novel Approach to Efficient Resource Allocation in NOMA Heterogeneous Networks: Multi-Criteria Green Resource Management

ABSTRACT

Nowadays, Green Communications has been introduced as an appealing approach to achieve the maximum degree of energy efficiency in new generation heterogeneous networks. To achieve the effective resource management, this paper suggests a novel approach to joint optimal power allocation and user association techniques in which cells are powered via a common grid network and alternative energy resources. This research focuses on resource assignment in energy-cooperated heterogeneous systems with non-orthogonal multiple access so that the quality of experience indexes are assumed to be bounded during multicell multicast sessions. The solution to the introduced problem has been developed to a mixed-integer programming framework in which the goal function is solved based on a Lagrangian convex optimization method by considering user association constraints. The effectiveness of the suggested approach has been confirmed by the numerical results and we compared the complexity of the proposed model to those of the conventional schemes. Also, the results reveal that non-orthogonal multiple access can provide greater energy efficiency than orthogonal multiple access in heterogeneous wireless networks.     

Crystallization and photo‐curing kinetics of biodegradable poly(butylene succinate‐co‐butylene fumarate) short‐segmented block copolyester

Short‐segmented block copolymers of poly(butylene succinate‐co‐butylene fumarate) were synthesized and their crystallinity and crosslinking behavior were investigated. ¹H NMR was used to characterize the microstructure and composition of the copolyesters. Molecular weight determination was performed using gel permeation chromatography. Based on the DSC results all copolyesters were crystalline and the degree of crystallinity of the copolymers did not change with butylene fumarate mole fraction due to co‐crystallization of the butylene succinate and butylene fumarate groups. Crosslinked copolyesters showed a lower crystallization rate and degree of crystallinity while the crystallization temperature shifted to higher temperatures compared with uncrosslinked copolyesters due to the formation of nucleating agents by crosslinkages. Photo‐DSC was used to investigate the crosslinking kinetics for UV‐initiated photo‐curing. Three kinetics parameters including the rate constant (k) and the orders of the initiation and propagation reactions (m and n, respectively) were determined for the quenched and unquenched copolymers. © 2016 Society of Chemical Industry     

Creep rupture assessment for Level-2 PSA of a 2-loop PWR: accounting for phenomenological uncertainties

The Level-2 probabilistic safety assessment (PSA) of pressurized water reactors studies the possibility of creep rupture for major reactor coolant system components during the course of high pressure severe accident sequences.The present paper covers this technical issue and tries to quantify its associated phenomenological uncertainties for the development of Level-2 PSA.A framework is proposed for the formal quantification of uncertainties in the Level-2 PSA model of a PWR type nuclear power plant using an integrated deterministic and PSA approach.This is demonstrated for estimation of creep rupture failure probability in station blackout severe accident of a 2-loop PWR,which is the representative case for high pressure sequences.MELCOR 1.8.6 code is employed here as the deterministic tool for the assessment of physical phenomena in the course of accident.In addition,a MATLAB code is developed for quantification of the probabilistic part by treating the uncertainties through separation of aleatory and epistemic sources of uncertainty.The probability for steam generator tube creep rupture is estimated at 0.17.     

Synthesis and characterization of novel polyurethanes based on aminolysis of poly(ethylene terephthalate) wastes,and evaluation of their thermal and mechanical properties

BACKGROUND: Much research is currently directed towards recycling post‐consumer poly(ethylene terephthalate) (PET) products for both environmental and economic reasons. Aminolysis of PET wastes using different amines, such as allylamine, morpholine, hydrazine and polyamines, leads to different reaction products as diamides of terephthalic acid, which do not possess any potential for further chemical reactions. In the past, the use of ethanolamine has been investigated for the aminolytic degradation of PET waste in the presence of different simple chemicals such as sodium acetate as catalysts. The product obtained, bis(2‐hydroxyethylene) terephthalamide (BHETA), has potential for further reactions to obtain useful products. Nevertheless, there has been no report on using recycled BHETA from PET to synthesize polyurethanes. RESULTS: In this research the product of aminolysis of PET waste, BHETA, was prepared. Then novel polyurethanes were synthesized based on the BHETA prepared, 1,4‐butanediol, ether‐type polyol and various molar ratios of hexamethylene diisocyanate. To evaluate the effect of BHETA, the properties of the polyurethanes without and with BHETA were compared. Fourier transform infrared spectra, thermal transitions, degradation, swelling ratio and chemical resistance of the synthesized polyurethanes were investigated. Also, the polyurethanes were applied as adhesives on various substrates. Comparison of the maximum bond strength of the synthesized polyurethane to that of commercial adhesives shows an about 2.2‐fold increase. CONCLUSION: It is possible to synthesize new polyurethanes with interesting properties using BHETA as an aminolysis product of PET waste. These kinds of materials have potential for many applications, such as adhesives and coatings. Copyright © 2008 Society of Chemical Industry     

Prediction of the Groundwater Rebound Process in a Backfilled Open Cut Mine Using an Artificial Neural Network

A neural network model was used to predict the groundwater rebound process after cessation of dewatering at a restored open cut coal site in the East Midlands area of the UK. Time (days after dewatering), water table levels in the aquifer and the backfilled site, hydraulic conductivity of the aquifer and backfilled site, and precipitation were used as input. The output of the network was the water table height, until the water table reached its equilibrium position. A feed-forward artificial neural network that uses batch gradient descent with a momentum-learning algorithm and 6-1-6-1 arrangement was found capable of predicting the groundwater rebound process. Predicted values were very close to the monitored results. The correlation coefficient values were 0.98221 for the training set, and 0.99329, 0.99499, 0.98667, 0.98289, and 0.97141 during the testing stage for the five monitoring points, showing that the model prediction was satisfactory.     

Development and characterisation of composite films made of kefiran and starch

In this study, new edible composite films were prepared by blending kefiran with corn starch. Film-forming solutions of different ratios of kefiran to corn starch (100/0, 70/30, 50/50, 30/70) were cast at room temperature. The effects of starch addition on the resulting films’ physical, mechanical and water–vapor permeability (WVP) properties were investigated. Increasing starch content from 0% to 50% (v/v) decreased the WVP of films; however, with further starch addition the WVP increased. Also, this increase in starch content increased the tensile strength and extensibility of the composite films. However, these mechanical properties decreased at higher starch contents. Dynamic mechanical thermal analysis (DMTA) curves showed that addition of starch at all levels increased the glass transition temperature of films. The electron scanning micrograph for the composite film was homogeneous, without signs of phase separation between the components. Thus, it was observed that these two film-forming components were compatible, and that an interaction existed between them.     

Characterization,microstructure and corrosion behavior of magnesia refractories produced from recycled refractory aggregates

This paper aims to report the results of some investigations carried out in Iranian steel industries to reuse the spent magnesia graphite refractory bricks in the forms of the new shaped and unshaped magnesia refractories. Economical aspects of recycling and minimizing the environmental effects of spent refractories landfills were the basic goals of this research. The spent MgO–C refractory bricks from electric arc (EAF) and ladle (LF) furnaces were analyzed in terms of microstructural and chemical properties. Different samples were prepared from natural sintered magnesia and 10–30 wt.% of recycled aggregates in the forms of magnesia refractory brick and ramming mix and their physical and mechanical properties were evaluated. Also the slag corrosion behavior and microstructural properties of corroded samples were investigated. The results showed that the addition of up to 30 wt.% of recycled aggregates had no negative effects on the properties of magnesia refractories.     

Enhanced Production of Iranian Kefir Grain Biomass by Optimization and Empirical Modeling of Fermentation Conditions Using Response Surface Methodology

This study focused on the optimization of key process parameters for maximizing kefir grain biomass yield using statistical methodology. A response surface methodology (RSM) was developed to describe the effects of whey lactose and yeast concentrations, temperature and pH on increases in kefir grain biomass using cheese whey as a fermentation medium. Initially, one factor at a time was applied to evaluate the effect of different nitrogen sources. The results showed that the concentration of yeast extract significantly influenced the biomass increase. Then, a 2⁴ full-factorial central composite design was used to optimize the process conditions. By using multiple regression analysis, the experimental data were fitted to a second-order polynomial model. RSM analysis indicated good correlation between experimental and predicted values. The most suitable combination of variables for higher biomass increase (76.13%) was 88.4 and 21.3 g/l, 5.2, and 20 °C for concentration of whey lactose, concentration of yeast extract, pH, and temperature, respectively. At these optimal conditions, biomass increased by 81.34%, which was close to the amount predicted by the model.     

High-Temperature Raman Spectra and Thermal Expansion of Wollastonite

Unpolarized single-crystal Raman spectra in the temperature interval of 298–1235 K and powder X-ray diffractometry data from room temperature up to 1295 K have been obtained from a natural triclinic wollastonite of almost-ideal composition. Room-temperature spectra, along with the temperature dependencies of nine major Raman modes, are presented. The temperature shifts of the Raman modes indicate a discontinuity in the temperature range of 950–980 K. No corresponding changes are observed in the temperature dependencies of the lattice parameters. Thermal expansion coefficients for the lattice parameters in the temperature range of 298–1295 K are given.