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Highlights • Chemical Conversion and hydrodynamics of fuel particle is studied simultaneously. • The effect of bed temperature is investigated on the devolatilization rate. • Pyrolysis time of particle is measured at different ranges of fluidization velocity. • Mass loss of the fuel particle is recorded due to the devolatilization. Abstract Measuring the temperature of a fuel particle during the thermochemical process inside the fluidized bed is of great importance in order to obtain detailed knowledge of the conversion behavior of the fuel particle and so optimize the combustion performance. In this study a number of experiments were done in order to register the temperature and hydrodynamics of a biomass fuel particle in a fluidized bed during the devolatilization process of a biomass particle. The experiments were done in a 2D fluidized bed with a front transparent window in order to use the particle image velocimetry (PIV) method to obtain information on the hydrodynamics of the fuel particle and inert bed material inside the bed. A thermocouple was also used to measure the temperature of the particle during the conversion. Experiments were done at a fluidized bed temperature and fluidization velocity in the range of 350–450 °C and 0.2–0.6 m/s, respectively. The effect of the bed’s temperature and fluidization velocity on the drying and devolatilization process of the biomass fuel particle was investigated. The results indicate that the bed’s temperature and fluidization velocity have a significant effect on the mass and heat transfer between the fuel particle and the bed during the conversion process. [ABSTRACT FROM AUTHOR]

Reduce activation ferritic/martensitic steels are candidate materials for future nuclear reactors due to their superior mechanical properties and reduced swelling under irradiation. In this research, single − crystal models of Fe-10%Cr have been built with [ 100 ] [ 010 ] [ 001 ] crystal orientations. The models stressed in both compression and tension by applying seven different pressures between −1000 MPa (tension) to +1000 MPa (compression) in uniaxial, biaxial, and hydrostatic cases. Displacement cascades have been initiated by imparting kinetic energy to an atom in the center of the simulation box. The produced point defects have been identified using the Wigner − Seitz cell method. In all cases, increasing the imparted energy increases the number of point defects. For models under uniaxial pressure, three different regions have been identified and each region has its own unique mechanism that controls the defect production process. For models under biaxial and hydrostatic pressure, the number of produced point defects increases with increasing the pressure in both tension and compression regions; in addition, the number of produced point defects with pressures shows an empirical power relationship. The Cr atoms prefer interstitial positions over creating vacancies in all cases. [ABSTRACT FROM AUTHOR]

Biomass as a renewable fuel compared to fossil fuels usually contains high moisture content and volatile release. Hydrogen production by large particle biomass gasification is a promising technology for utilizing high moisture content biomass particle in the high temperature fluidized bed reactor. In the present work, simulation of large particles biomass gasification investigated at high temperature by using the discrete phase model (DPM). Combustible gases with homogeneous gas phase reactions, drying process with a heterogeneous reaction, primary and secondary pyrolysis with independent parallel-reaction by using two-competing-rate model to control a high and low temperature were used. During the thermochemical process of biomass, gaseous products containing of H 2 , H 2 O, CH 4 , CO and CO 2 was obtained. The effects of concentration, mole and mass fraction and hydrodynamics effects on gaseous production during gasification were studied. The results showed that hydrodynamic effect of hot bed is different from cold bed. Concentration and molar fraction of CO and H 2 production by continually and stably state and small amount of CO 2 , H 2 O, and CH 4 was obtained. The hydrodynamic of bed plays the significant role on the rate of gaseous products. [ABSTRACT FROM AUTHOR]

The presence of initial stress in solids changes the material's response to finite and infinitesimal deformations. This paper presents a study on the effects of initial stress, finite deformation, and material properties on the speed of interfacial waves which are assumed to travel at the joint boundary of two incompressible half-spaces. The theory of infinitesimal deformations superimposed on finite deformations is used along with the theory of invariants. Boundary conditions at the interface result in an explicit secular equation, which is analyzed generally. For each half-space, a prototype strain–energy function is assumed, which is a function of the deformation gradient and initial stress tensors. The effect of different governing parameters is observed on the wave speed and is analyzed theoretically. Graphical illustrations are also presented to elaborate on the theoretical results. It is observed that for admissible values of parameters, a real wave speed exists and is bounded by values depending on the governing parameters. A comparison between Rayleigh and interfacial wave speeds is also made and supported with graphs of dimensionless wave speeds with respect to initial stresses. • The effect of initial stress on the interfacial waves is studied. • An explicit secular equation is obtained which is analyzed generally. • For a particular strain–energy function, a real wave speed exists which is bounded. • A comparison between Rayleigh and interfacial wave speeds is also presented. • It is found that the interfacial wave speed is affected by the initial-stress. [ABSTRACT FROM AUTHOR]

With the presence of ever-rising customers' concerns about environmental impacts, companies are utilizing used products and recyclable materials in their supply chains to manage the products' end-of-life effectively. Effective utilization requires a proper logistical structure to flow used and recovered products throughout the supply chain. In the carpet industry, reverse logistics operations are complex and susceptible to high uncertainty affecting the collection rate, recovered items' availability, and reverse channel capacity. Besides total cost efficiency, carpet manufacturers and other logistics actors are willing to plan the production and reverse logistics functional areas to optimize sustainability attributes. Armed with these insights, this paper addresses a multi-product, multi-site, and multi-period production planning problem integrated with reverse logistics under uncertainty. A novel fuzzy multi-objective programming model (combining possibility and flexibility) is proposed with chance constraints. Finally, new hybrid fuzzy goal programming is presented to solve the developed model. Numerical study in the carpet industry is included to show the model applicability and sensitivity. • Integration of (reverse/forward) logistics, production and transportation planning through the lens of sustainability. • Carbon dioxide emissions and energy consumption are contemplated. • We incorporate systems' soft constraints with a dynamic nature and data fuzziness into a mathematical programming model. • A possibility-based chance-constraint programming and g -ranking function are successfully utilized to derive an equivalent defuzzified model. • A real-life-like numerical example in woven carpet industry is studied. [ABSTRACT FROM AUTHOR]

Abstract: Agrobacteria are common soil bacteria that interact with plants as commensals, plant growth promoting rhizobacteria or alternatively as pathogens. Indigenous agrobacterial populations are composites, generally with several species and/or genomic species and several strains per species. We thus developed a recA-based PCR approach to accurately identify and specifically detect agrobacteria at various taxonomic levels. Specific primers were designed for all species and/or genomic species of Agrobacterium presently known, including 11 genomic species of the Agrobacterium tumefaciens complex (G1-G9, G13 and G14, among which only G2, G4, G8 and G14 still received a Latin epithet: pusense, radiobacter, fabrum and nepotum, respectively), A. larrymoorei, A. rubi, R. skierniewicense, A. sp. 1650, and A. vitis, and for the close relative Allorhizobium undicola. Specific primers were also designed for superior taxa, Agrobacterium spp. and Rhizobiaceace. Primer specificities were assessed with target and non-target pure culture DNAs as well as with DNAs extracted from composite agrobacterial communities. In addition, we showed that the amplicon cloning-sequencing approach used with Agrobacterium-specific or Rhizobiaceae-specific primers is a way to assess the agrobacterial diversity of an indigenous agrobacterial population. Hence, the agrobacterium-specific primers designed in the present study enabled the first accurate and rapid identification of all species and/or genomic species of Agrobacterium, as well as their direct detection in environmental samples. [Copyright &y& Elsevier]

Abstract: This work discusses the development of a three-dimensional Eulerian–Lagrangian CFD model for a gas–liquid flow in a rectangular column. The model resolves the time-dependent, three-dimensional motion of small gas bubbles in a liquid to simulate the dynamic characteristics of the oscillating bubble plume. Our model incorporates drag, gravity, buoyancy, lift, pressure gradient and virtual mass forces acting on a bubble rising in a liquid, and accounts for two-way momentum coupling between the phases. We use MUSIG model that provides a framework in which the population balance method together with the break up and coalescence models can be incorporated into three-dimensional CFD calculations. We use turbulent flow to describe liquid flow field. The standard κ–ε of turbulence is selected for calculating the properties of turbulent flow. The effect of aspect ratio of the column on the flow pattern, liquid velocity and gas hold-up profiles is discussed. [Copyright &y& Elsevier]

Abstract: This paper presents a methodology to quantitatively gauge the potential economical loss due to unobserved faults when standard statistical monitoring charts are used. It is shown that in closed loop operation, a shorter time for detection may result from retuning the controller at the expense of higher product variability. Accordingly, an optimization approach is proposed for finding a trade-off between the economic losses resulting from lack of detection and losses resulting from higher product variability. In order to account for faults with different frequency contents, the method is applied in the frequency domain. The proposed optimization based methodology is later validated in the time domain. [ABSTRACT FROM AUTHOR]

Abstract: If the hydrodynamic diameter of a channel is comparable with the mean free path of the gas molecules moving inside the channel, the fluid can no longer be considered to be in thermodynamic equilibrium and a variety of non-continuum or rarefaction effects can occur. To avoid enormous complexity and extensive numerical cost encountered in modeling of nonlinear Boltzmann equations, the Navier–Stokes equations can be solved considering the concepts of slip flow regime and applying slip velocity boundary conditions at the solid walls. In this study, the Navier–Stokes and energy equations for fluid flow in a microchannel in slip flow regime were solved analytically and temperature and velocity profiles were evaluated. The effect of different parameters on heat transfer and dispersion of nanoparticles was discussed. Dispersion of particles due to drag force, Saffman lift force, Brownian forces and gravity force was studied using a Lagrangian approach. The presented results could provide guidelines for heat transfer modeling in nanofluids. [Copyright &y& Elsevier]

Abstract: Microgeometry fluid dynamics has gotten a lot interest due to the arrival of Micro-Electro-Mechanical systems (MEMS). When the mean free path of a gas and characteristic length of the channel are in the same order, continuum assumption is no longer valid. In this situation velocity slip and temperature jump occur in the duct walls. Fully developed numerical analysis for characteristic laminar slip flow and heat transfer in rhombus microchannels are performed with slip velocity, and temperature-jump boundary condition at walls. The impacts of Reynolds number (0.1< Re <40), velocity slip, and temperature-jump on Poiseuille number, and Nusselt number for different aspect ratio (0.15

Abstract: A two dimensional numerical simulation is performed for incompressible and compressible fluid flows through microchannels in slip flow regime with consideration of slip and temperature jump boundary conditions. The wall roughness is simulated in two cases with triangular microelements and random shaped micro peaks distributed on wall surfaces to study the effects of roughness shape and distribution on the flow field. Various Mach and Knudsen numbers have been used to investigate the effects of rarefaction as well as compressibility. It is found that rarefaction has a more significant effect on the flow field in microchannels with higher relative roughness. It is also found that the effect of compressibility will be more noticeable when relative roughness increases. In addition a high influence of roughness distribution and shape can be seen for both compressible and incompressible flows. The numerical results have also been checked with available theoretical and experimental relations and a good agreement has been achieved. [Copyright &y& Elsevier]

Abstract: A numerical simulation for studying fluid flow and heat transfer characteristics in microchannels at slip flow regime with consideration of slip and temperature jump is studied. The wall roughness is simulated in two cases with periodically distributed triangular microelements and random shaped micro peaks distributed on the wall surfaces. Various Knudsen numbers have used to investigate the effects of rarefaction. The numerical results have also checked with available theoretical and experimental relations and good agreements has achieved. It has been found that rarefaction has more significant effect on flow field in microchannels with higher relative roughness. The negative influence of roughness on fluid flow and heat transfer found to be the friction factor increment and Nusselt number reduction. In addition high influence of roughness distribution and shape has been shown by a comparison of Poiseuille and Nusselt numbers for tow different cases. [Copyright &y& Elsevier]

We have written out all shifting algorithm in the QR corresponding to article [SIAM J. Matrix Anal. 12 (1991) 385], specially the block shift algorithm, and tested them with Maple8. A comparison table has been designed in each case to compare the implementation of the algorithms with each other. The differences of the shifts have been noted in the last section. [Copyright &y& Elsevier]