Physical and Morphological Properties of Combined Treated Wood Polymer Composites by Maleic Anhydride and Methyl Methacrylate

Wood polymer composites were prepared by consecutive impregnation with maleic anhydride (MAN) and methyl methacrylate (MMA). Samples impregnated with MAN alone, were heated at 120°C and 150°C for 4 and 8 h. Based on the Fourier transform infrared (FT-IR) analysis and soaking-drying test results, treatment with MAN at 150°C for 4 h resulted in formation of stable crosslinks. In the second stage, MMA was used for in situ polymerization within MAN-treated wood. Field emission scanning electron microscopy observation and FT-IR analysis indicated that MMA copolymerized with MAN, and the resultant polymer filled up the lumen and is also grafted on to the cell wall. Improvement of water repellency and dimensional stability were observed in the treated samples, particularly in combined treated samples. The MAN/MMA treatment improved interaction between polymer and wood.     

Analytical formulation of transient oscillation amplitude in rotary traveling wave oscillators

This paper presents an accurate analysis for deriving transient oscillation amplitude of Rotary Traveling Wave Oscillators (RTWOs) as a transmission-line based and high frequency circuit. The procedure of the paper is based on considering the nonlinear behavior of negative transconductors that are used for loss compensation of the transmission line. Finally, a closed-form expression for the time-domain amplitude of the RTWOs is obtained. The proposed useful and accurate expression could be used for designing the RTWOs for high performance-high speed systems. Also, it enables us to analyze and synthesize the oscillators with the desired transient behavior. This aspect of the RTWOs is not studied in previous works. The proposed theoretical results are then compared with accurate simulations. Simulations have been done in 0.18 μm CMOS technology with 1.8 V supply voltage. Results show less than 10% difference in steady state oscillation amplitude of theoretical expression and simulations. Considering the nonlinear equation of the RTWOs amplitude, complicated type of solving, simplifications and its numerical solution, the proposed derived expression has a good agreement with simulations.     

Stochastic models for transfer point location problem

The transfer point location problem has been introduced recently and for the case of minimax objective and planar topology, has only been studied for situations in which demand points are not weighted and have known coordinates. In this paper, we consider the case in which demand points are weighted and their coordinates have bivariate uniform distribution. Also, the problem is developed from a conceptual view and different distance measures are used to make models more applicable in real world situations. The problem is to find the best location for the transfer point such that the maximum expected weighted distance to all demand points through the transfer point is minimized. Depending on assumptions for uniform distributions, two models are considered, convexity conditions are discussed, properties of the optimal solution are obtained and methods to solve the problems are proposed. Finally, numerical examples are given.     

Effect of deep cryogenic processing on tensile toughness of 45WCrV7 steel

Toughness is an important property for being used in steels in engineering applications. In this research, tensile toughness of 45WCrV7 steel was measured and calculated in 10 different processing conditions. The results of tensile test showed that two samples had maximum tensile toughness. Microstructural studies demonstrated that the required condition for high tensile toughness was simultaneous increase in two microstructural factors named content and population density of the secondary carbides because a matrix which was poor of carbon and alloying elements was softened and thus increased total tensile toughness.     

Optimising the ice cream formulation using basil seed gum (Ocimum basilicum L.) as a novel stabiliser to deliver improved processing quality

Mixture design was used to determine the optimum ratio as well as concentration of basil seed gum (BSG), guar gum (GG) and carboxymethyl cellulose (CMC) in the formulation of ice cream stabilisers. Predicted equations and contour plots of physicochemical responses were also generated. Generally, increasing the ratio of BSG in gums mixture increased the apparent viscosity of ice cream mixes and decreased the melting rate. Increasing the proportion of GG at concentration of 0.35% enhanced overrun of samples. High ratios of BSG at concentration of 0.35% and CMC at concentration of 0.15% increased the fat destabilisation in ice creams. Combination of 84.31% BSG and 15.69% CMC at concentration of 0.35% proposed as optimum formulation which verified in practice. Introducing BSG as a novel source of stabiliser could be promising as alternative and improve the quality and diversity of ice cream and related products.     

Bitter sweet: How sustainable is bio-ethanol production in Brazil?

While biofuels have currently been regarded as a good alternative for fossil fuels, there remain many debates on their impacts on human and environment. This paper tried to shed light on bio-ethanol in Brazil as one of the main producers and exporters in the world. The main question was to understand “how sustainable is bio-ethanol production in Brazil?” To answer, the political motives of producing bio-ethanol followed by its ecological and socio-economic impacts were discussed. The paper concluded that although bio-ethanol production in Brazil seems environmentally friendly, it might socio-economically be hazardous.     

An iterative learning approach for network contraction: Path finding problem in stochastic time‐varying networks

Path finding problem has a broad application in different fields of engineering. Travel time uncertainty is a critical factor affecting this problem and the route choice of transportation users. The major downside of the existing algorithms for the reliable path finding problem is their inefficiency in computational time. This study aims to develop a network contraction approach to reduce the network size of each specific origin and destination (OD) pair in stochastic time‐dependent networks. The network contraction is based on the comparison of optimistic and pessimistic solutions resulting from minimum and maximum travel time realizations of a Monte‐Carlo simulation (MCS)‐based approach. In this respect, the researchers propose a learning approach to utilize the information of the realizations in the initial iterations of the MCS approach. Implementation of this approach is in place for several OD pairs of two real‐world large‐scale applications. First, it is calibrated for the Chicago downtown network; the performance and accuracy of the proposed approach are investigated by comparing the results against that of the approach without any network contraction. In addition, the Salt Lake City network illustrates the transferability of the approach to other networks. The results demonstrate significant computational improvements, with an acceptable accuracy level relative to the approach without network contraction.