Measurement of residual stress by using focused ion beam and digital image correlation method in thin-sized wires used for steel cords

Residual stress in the axial direction of the steel wires has been measured by using a method based on the combination of the focused ion beam (FIB) milling and digital image correlation software. That is, the residual stress was calculated from the measured displacement field before and after the introduction of a slot along the steel wires. The displacement was obtained by the digital correlation analysis of high-resolution scanning electron micrographs, while the slot was introduced by FIB milling with low energy beam. The fitting of the experimental results to an analytical model with the independent Young's modulus determined allows us to find the residual stress. The complete experimental procedures are described and its feasibilities are also evaluated for the thin-sized steel wires.open112sciescopu

The intermediate pyrolysis of de-inking sludge to produce a sustainable liquid fuel

De-inking sludge is a waste product generated from secondary fibre paper mills who manufacture recycled paper into new paper sheets; it refers directly to the solid residues which evolve during the de-inking stage of the paper pulping process. The current practice for the disposal of this waste is either by land-spreading, land-filling or incineration which are unsustainable. This work has explored the intermediate pyrolysis of pre-conditioned de-inking sludge pellets in a recently patented 20 kg/h intermediate pyrolysis reactor (The Pyroformer). The reactor is essentially two co-axial screws which are configured in such a way as to circulate solids within the reactor and thus facilitate in the cracking of tars. The potential application of using the volatile organic vapours and permanent gases evolved would be to generate both combined heat and power (CHP) located at paper making sites. The results show that de-inking sludge could be successfully pyrolysed and the organic vapours produced were composed of a mixture of aromatic hydrocarbons, phenolic compounds and some fatty acid methyl esters as detected by liquid GC-MS. The calorific value of the oil after condensing was between 36 and 37 MJ/kg and the liquid fuel properties were also determined, permanent gases were detected by a GC-TCD and were composed of approximately 24% CO, 6% CH and 70% CO (v/v%). The solid residue from pyrolysis also contained a small residual calorific value, and was largely composed of mainly calcium based inert metal oxides. The application of applying intermediate pyrolysis to de-inking sludge for both CHP production and waste reduction is in principle a feasible technology which could be applied at secondary fibre paper mills

Efficient adaptive importance sampling for time-dependent reliability analysis of structures

Various methods have been used by researchers to evaluate the time-dependent reliability of structures. Among them, the stochastic-process-based method is theoretically the most rigorous but also computationally the most expensive. To enable the wide application of the stochastic-process-based method in the time-dependent reliability analysis of complex problems, an efficient importance sampling method is presented. This new method, extended from an existing method for time-independent reliability analysis, offers an efficient solution for time-dependent problems of structural systems with multiple important regions. Furthermore, to enhance the efficiency and robustness of the proposed method, a number of numerical measures are proposed. The capability and efficiency of the proposed method are demonstrated through two numerical examples

FPGA Implementation of a Parameterized Fourier Synthesizer

International audienceField-Programmable Gate Array (FPGA) offers advantages for many applications, particularly where missions are complex and time performance is critical. For small-production digital acoustic synthesizers, FPGA can achieve the above-mentioned tighter system requirements with low total system costs on single chip. In this manuscript, a real-time acoustic synthesizer is implemented using Fourier series algorithm on Altera's Cyclone II FPGA chip. This work emphasizes systematic designs and parallel computations. The proposed system includes a flexible processor and a parallel parameterized acoustic module. On one hand, the Nios II embedded processor, which is relatively low-speed component, is used to generate commands and configure high-speed acoustic module parameters. On the other hand, acoustic module which should require high-speed components contains 4 parallel architectures to gain high-speed simultaneous calculus of 4 independent digital timbres. Every timbre is equivalent to 16 parallel high-precision harmonic channels with 0.3 % frequency error. Experimental results corroborate the fact that a single FPGA chip can achieve complex missions and attain real-time performances

Intermediate pyrolysis of biomass energy pellets for producing sustainable liquid, gaseous and solid fuels

This work describes the use of intermediate pyrolysis system to produce liquid, gaseous and solid fuels from pelletised wood and barley straw feedstock. Experiments were conducted in a pilot-scale system and all products were collected and analysed. The liquid products were separated into an aqueous phase and an organic phase (pyrolysis oil) under gravity. The oil yields were 34.1 wt.% and 12.0 wt.% for wood and barley straw, respectively. Analysis found that both oils were rich in heterocyclic and phenolic compounds and have heating values over 24 MJ/kg. The yields of char for both feedstocks were found to be about 30 wt.%, with heating values similar to that of typical sub-bituminous class coal. Gas yields were calculated to be approximately 20 wt.%. Studies showed that both gases had heating values similar to that of downdraft gasification producer gas. Analysis on product energy yields indicated the process efficiency was about 75%

Field Redefinitions, T-duality and Solutions in Closed String Field Theories

We investigate classical solutions in closed bosonic string field theory and heterotic string field theory that are obtained order by order starting from solutions of the linearized equations of motion, and we discuss the ``field redefinitions'' which relate massless fields in the string field theory side and the low energy effective theory side. Massless components of the string field theory solutions are not corrected and from them we can infer corresponding solutions in the effective theory: the chiral null model and the pp-wave solution with B-field, which have been known to be alpha'-exact. These two sets of solutions in the two sides look slightly different because of the field redefinitions. It turns out that T-duality is a useful tool to determine them: We show that some part of the field redefinitions can be determined by using the correspondence between T-duality rules in the two sides, irrespective of the detail of the interaction terms and the integrating-out procedure. Applying the field redefinitions, we see that the solutions in the effective theory side are reproduced from the string field theory solutions.Comment: LaTeX, 40 pages, no figure v2: minor corrections v3: minor correctio

Analysis of Two-Body Decays of Charmed Baryons Using the Quark-Diagram Scheme

We give a general formulation of the quark-diagram scheme for the nonleptonic weak decays of baryons. We apply it to all the decays of the antitriplet and sextet charmed baryons and express their decay amplitudes in terms of the quark-diagram amplitudes. We have also given parametrizations for the effects of final-state interactions. For SU(3) violation effects, we only parametrize those in the horizontal $W$-loop quark diagrams whose contributions are solely due to SU(3)-violation effects. In the absence of all these effects, there are many relations among various decay modes. Some of the relations are valid even in the presence of final-state interactions when each decay amplitude in the relation contains only a single phase shift. All these relations provide useful frameworks to compare with future experiments and to find out the effects of final-state interactions and SU(3) symmetry violations.Comment: 28 pages, 20 Tables in landscape form, 4 figures. Main changes are: (i) some errors in the Tables and in the relations between the quark-diagram amplitudes of this paper and those of Ref.[10] are corrected, (ii) improvements are made in the presentation so that comparisons with previous works and what have been done to include SU(3) breaking and final-state interactions are more clearly stated; to appear in the Physical Review

Holonomy Transformation in the FRW Metric

In this work we investigate loop variables in Friedman-Robertson-Walker spacetime. We analyze the parallel transport of vectors and spinors in several paths in this spacetime in order to classify its global properties. The band holonomy invariance is analysed in this background.Comment: 8 page

Combined heat and power from the intermediate pyrolysis of biomass materials:performance, economics and environmental impact

Combined heat and power from the intermediate pyrolysis of biomass materials offers flexible, on-demand renewable energy with some significant advantages over other renewable routes. To maximise the deployment of this technology an understanding of the dynamics and sensitivities of such a system is required. In the present work the system performance, economics and life-cycle environmental impact is analysed with the aid of the process simulation software Aspen Plus. Under the base conditions for the UK, such schemes are not currently economically competitive with energy and char products produced from conventional means. However, under certain scenarios as modelled using a sensitivity analysis this technology can compete and can therefore potentially contribute to the energy and resource sustainability of the economy, particularly in on-site applications with low-value waste feedstocks. The major areas for potential performance improvement are in reactor cost reductions, the reliable use of waste feedstocks and a high value end use for the char by-product from pyrolysis

The totally asymmetric exclusion process on a ring: Exact relaxation dynamics and associated model of clustering transition

The totally asymmetric simple exclusion process in discrete time is considered on finite rings with fixed number of particles. A translation-invariant version of the backward-ordered sequential update is defined for periodic boundary conditions. We prove that the so defined update leads to a stationary state in which all possible particle configurations have equal probabilities. Using the exact analytical expression for the propagator, we find the generating function for the conditional probabilities, average velocity and diffusion constant at all stages of evolution. An exact and explicit expression for the stationary velocity of TASEP on rings of arbitrary size and particle filling is derived. The evolution of small systems towards a steady state is clearly demonstrated. Considering the generating function as a partition function of a thermodynamic system, we study its zeros in planes of complex fugacities. At long enough times, the patterns of zeroes for rings with increasing size provide evidence for a transition of the associated two-dimensional lattice paths model into a clustered phase at low fugacities.Comment: 9 pages 5 figures accepted for publication in Physica