Preparation of cerium oxide nanoparticles in Salvia Macrosiphon Boiss seeds extract and investigation of their photo-catalytic activities

Cerium oxide nanoparticles (CNPs) with desired particle size and spherical morphology were prepared from cerium nitrate in bio media of Salvia macrosiphon Boiss seeds extract, as a green synthesis route. Then they were characterized by XRD, UV–Vis and FTIR spectroscopies, FESEM and TGA. Band gap energy of the prepared powders was also determined which was found in the range of 2.5–3.5?eV. Determination of DLS and zeta potential were showed that CNPs had the small size and unique colloidal stability, respectively. Then the photo-catalytic activity of them was investigated by degradation of Rhodamine B (RhB) dye as a model of waste water pollutants, under UV-irradiation and optimum conditions were evaluated. Results showed that decreasing the particle size increased the rate of photo-catalytic reaction remarkably but ascending the band gap energy, in contrast. The photo-catalytic mechanism was also studied by using different scavengers.     

Hydrogen production from co-gasification of asphaltene and plastic

At present, due to the environmental considerations and world energy crisis, there is a growing trend towards using gasification instead of combustion as a thermochemical route for power generation. The purpose of this work was to provide a computer-based model to predict the potential of gasification process for syngas production. The influence of the most important operational conditions namely asphaltene/plastic mass ratio (A/P), steam/fuel ratio (S/F), gasification temperature (T_gas), and equivalence ratio (ER) on gas composition and tar concentration was evaluated. With the asphaltene/plastic ratio (A/P) increasing from 0.2 (wt/wt) to 0.6 (wt/wt), the carbon conversion efficiency (CCE) initially increases from 47.88% to 54.61% for S/F = 0.25, from 49.80% to 54.11% for S/F = 0.5, from 51.83% to 58.36% for S/F = 0.75, and from 52.69% to 60.57% for S/F = 1.0, then steadily decreased. The gas yield also increased from 45.12 (%) to 92.08 (%) with increasing ER from 0.1 to 0.8, while the tar yield decreased from 12.24 (%) to 00.14 (%).     

Power allocations in minimum-energy SER-constrained cooperative networks

In this paper, we propose minimum power allocation strategies for repetition-based amplify-and-forward (AF) relaying, given a required symbol error rate (SER) at the destination. We consider the scenario where one source and multiple relays cooperate to transmit messages to the destination. We derive the optimal power allocation strategy for two-hop AF cooperative network that minimizes the total relay power subject to the SER requirement at the destination. Two outstanding features of the proposed schemes are that the power coefficients have a simple solution and are independent of knowledge of instantaneous channel state information (CSI). We further extend the SER constraint minimum power allocation to the case of multibranch, multihop network and derive the closed-form solution for the power control coefficients. For the case of power-limited relays, we propose two iterative algorithms to find the power coefficients for the SER constraint minimum-energy cooperative networks. However, this power minimization strategy does not necessarily maximize the lifetime of battery-limited systems. Thus, we propose two other AF cooperative schemes which consider the residual battery energy, as well as the statistical CSI, for the purpose of lifetime maximization. Simulations show that the proposed minimum power allocation strategies could considerably save the total transmitted power compared to the equal transmit power scheme.     

One-Step Synthesis of Zirconia and Magnetite Nanocomposite Immobilized Chitosan for Micro-Solid-Phase Extraction of Organophosphorous Pesticides from Juice and Water Samples Prior to Gas Chromatography/Mass Spectroscopy

In this research, a magnetic sorbent was prepared by immobilizing zirconia and magnetite (Fe₃O₄) nanoparticles in chitosan, which is characterized and used as an effective nanosorbent in magnetic dispersive micro-solid-phase extraction (MDMSPE) of organophosphorous pesticides (OPPs) from juice and water samples prior to gas chromatography-mass detection (GC-MS). The properties and morphology of synthesized sorbent were characterized by scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM), and differential scanning calorimetric (DSC) analysis. The main experimental parameters including pH level, extraction time, sorbent mass, salt concentration, and desorption conditions were investigated and optimized to maximize extraction efficiency. Under optimized conditions, the calibration curves were obtained in the concentration range of 0.1–500 ng mL^?1 with correlation coefficients between 0.9993 and 0.9999. The limits of detection (signal-to-noise ratio (S/N) = 3) and limits of quantification (S/N = 10) of the method ranged from 0.031 to 0.034 ng mL^?1 and 0.105–0.112 ng mL^?1, respectively. The intra-day and inter-day RSDs were 2.2–5.7 and 2.5–7.5%, respectively. The method was successfully applied to the analysis of OPPs in fruit juices (apple, peach, and cherry) and water (mineral, tap, and river) real samples, with recoveries in the range of 86.0–106.0% for the spiked juice and water samples. The results showed that with combination of high selectivity of zirconia and magnetic property of magnetite as well as immobilizing ability of chitosan, the fabricated sorbent exhibited exceptional extraction ability toward the OPPs.     

Modeling and evaluating the time overhead induced by BER in COMA multiprocessors

Designing multiprocessors based on distributed shared memory (DSM) architecture considerably increases their scalability. But as the number of nodes in a multiprocessor increases, the probability of encountering failures in one or more nodes of the system raises as a serious problem. Thus, every large-scale multiprocessor should be equipped with mechanisms that tolerate node failures. Backward error recovery (BER) is one of the most feasible strategies to build fault tolerant multiprocessors and it can be shown that among various DSM-based architectures, cache only memory architecture (COMA) is the most suitable for implementing BER. The main reason is the existence of built-in mechanisms for data replication in COMA memory system. BER is applicable to COMA multiprocessors with minor hardware redundancy, but it will obviously cause some other kinds of overheads. The most important overhead induced by BER is the time required to produce and store recovery data. This paper introduces an analytical model for predicting the amount of this time overhead and then verifies the correctness of the model through comparing the results predicted from this model with the previously published simulation results. Both the analytical model and simulation results show that the overhead is nearly independent of the number of nodes. The immediate result is that BER is a cost-effective strategy for tolerating node failures in large-scale COMA multiprocessors with large numbers of nodes.     

A stochastic model of cash flow forecasting considering delays in owners’ payments

Delays in progress payments have always been one of the most aggravating difficulties, threatening the desired profit margin and should be considered based on the owners’ financial records at the bidding stage. However, previous models have often ignored the probabilistic nature of cash inflow. The conducted research endeavours to develop a new stochastic simulation-based framework for forecasting the cash flow of the construction projects considering the owners’ payment history in previous projects and intertemporal correlation between successive progress payments. This process involves introducing the Budget Realization Index, with probabilistic nature, whose underlying distribution is determined based on the owners’ behaviour. The model was applied to four real projects in Iran. The financing costs inflicted on the contractors stood in the range of the simulation results in the uncertainty level of 50–80%. Therefore, the proposed systematic framework would appropriately perform for forecasting contractors’ financial status through the project.     

Investigation on the formation of roll waves in chutes

Roll waves create unstable and turbulent behaviour in channels and chutes and also change the behaviour of water entering the energy dissipater structures. In the present study, the free surface of water in the chute is simulated by numerical models. The roll waves’ occurrence is investigated in the numerical model for the discharge up to 30 m³/s, the longitudinal slope varying from 17 to 20% and the width of chute varying from 3.4 to 4.0 m. The ratios of the hydraulic depth to the chute width and also the minimum velocity to the maximum velocity are calculated along the chute length for different discharges, widths and longitudinal slopes of the chute. Results indicated that for the chutes in which the ratio of hydraulic depth to the chute width less than 0.16 the ratio of minimum to maximum velocity is less than 0.75, the formation of roll waves is inevitable.     

Experimental and numerical study of distortion in flat,L‐shaped,and U‐shaped carbon fiber–epoxy composite parts

In this study, flat composite panels were fabricated to find the effect of different manufacturing parameters, including stacking sequence, part thickness, and tooling material, on distortion of carbon fiber‐epoxy composite parts. L‐shaped and U‐shaped panels were also made to investigate the effect of stacking sequence on spring‐in angle and warpage of the curved panels. Results showed that distortion of the flat panels caused by asymmetry in the stacking sequence was an order of magnitude greater than distortion of the panels with an unbalanced stacking sequence; whereas in the curved panels, the panel with an asymmetric stacking sequence showed the least spring‐in angle, and the largest angle was observed in the symmetric panel. MSC Marc was used to predict distortion of the panels, and the simulation results were compared with the experimental results for several stacking sequences of the flat and the L‐shaped panels. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40439.     

Cellulose Acetate Nanofibres Containing Alizarin as a Halochromic Sensor for the Qualitative Assessment of Rainbow Trout Fish Spoilage

A halochromic sensor of cellulose acetate nanofibres and alizarin as a fish spoilage indicator in real time is described. The colour of this on-packaging sensor changes visually with an increase in the amount of total volatile basic nitrogen (TVB-N) and a rise in the pH value of product. Rainbow trout fillets were kept at refrigerator temperature (4 °C) for 12 days. TVB-N, pH, total viable count (TVC) and colourimetric tests were performed. Results showed that the pH, the TVB-N and the TVC increased with time. No colour changes were observed within 48 h, but after the fourth day, a very light brick colour on the nanosensor was observed. This colour became darker on the sixth day, representing actual pH changes. The colour of sensor tended towards violet on the 12th day; the colourimetric result proved the expected visual colour change in the electrospun nanosensor due to alizarin usage as a halochromic dye.     

Recent development on recovering bioactive peptides and phenolic compounds from under-utilised by-products during production of certain edible oil plants: current situation and future perspectives

During the edible oil production process, massive amounts of by-products are generated each year that are not efficiently utilised, posing economic and environmental challenges. Under-utilised products derived from valuable oil-plants such as oil-extracted wheat germ, oil-extracted moringa seed, oil-extracted walnut and flaxseed meal will be increased, and new integration concepts will be required as soon as possible. These underutilised products can be rich sources of phenolic compounds and bioactive peptides with appropriate health-promoting properties such as anti-diabetic, antioxidant, anti-hypertensive, anti-inflammatory, anticancer and antibacterial properties, according to this review. The recovery of bioactive compounds from these by-products can go a long way toward ensuring a sustainable food supply. Current challenges and requirements for recovering bioactive peptides and phenolic compounds from underutilised products derived from valuable oil-plants as well as the relationship between their biological activity and structure are discussed in this study.