Quality sentries: some trends in chocolate manufacturing

In-line control elements are an increasing development in the pursuit of efficient processes in a wide range of manufacturing sectors. Advances in sensor technology and computing power are now providing instruments which can greatly improve the efficiency and accuracy of manufacturing, and at a cost which is moderate in comparison with other costs, such as raw material prices and fuel costs. In the food sector, there are two clear incentives for pursuing in-line monitoring capabilities. Firstly, they raise the quality of the foods produced and secondly, they reduce the waste of valuable raw materials. Increasing commodity prices in regard to food ingredients give particular importance to this aspect

Injecting Shortcuts for Faster Running Java Code

Genetic Improvement of software applies search methods to existing software to improve the target program in some way. Impressive results have been achieved, including substantial speedups, using simple operations that replace, swap and delete lines or statements within the code. Often this is achieved by specialising code, removing parts that are unnecessary for particular use-cases. Previous work has shown that there is a great deal of potential in targeting more specialised operations that modify the code to achieve the same functionality in a different way. We propose six new edit types for Genetic Improvement of Java software, based on the insertion of break, continue and return statements. The idea is to add shortcuts that allow parts of the program to be skipped in order to speed it up. 10000 randomly-generated instances of each edit were applied to three open-source applications taken from GitHub. The key findings are: (1) compilation rates for inserted statements without surrounding "if" statements are 1.5-18.3%; (2) edits where the insert statement is embedded within an "if" have compilation rates of 3.2-55.8%; (3) of those that compiled, all 6 edits have a high rate of passing tests (Neutral Variant Rate), >60% in all but one case, and so have the potential to be performance improving edits. Finally, a preliminary experiment based on local search shows how these edits might be used in practice

Development of a single droplet freezing apparatus for studying crystallisation in cocoa butter droplets

The single droplet freezing apparatus described by Pore et al. (J. Am. Oil. Chem. Soc., 86, 215-225), which allows crystallisation to be monitored in situ by X-ray diffraction, was modified to allow rapid switching of coolant gas and monitoring by video microscopy. The apparatus was used to study drops of cocoa butter undergoing simulated spray freezing at high cooling rates, e.g. 130 K/min. The transformation of an Ivory Coast cocoa butter to the Form V polymorph was significantly faster in drops (~40 h) than in static bulk samples (10 days) crystallised under isothermal conditions. Phase transformation was observed from Forms I/II → III → IV → melt → V, with Form V crystallising directly from the melt at 28.6°C. Numerical simulations of the temperature evolution within the droplet established that the drops are not isothermal, explaining why nucleation was initially observed in the lower (upstream) part of the droplet.The provision of an EPSRC studentship for AMT and project support from Nestlé PTC York is gratefully acknowledged. The apparatus was constructed by Lee Pratt, Gary Chapman, Kevin Swan and Wei-Yao Ma. Assistance with the DSC testing from Zlatko Saraçevic, video microscopy from Dr Simon Butler, and general X-ray analysis from Dr Joanna Stasiak are all gratefully acknowledged.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.jfoodeng.2015.02.01

Optimal k-space sampling for single point imaging of transient systems

A modification of the Single Point Imaging (SPI) is presented. The novel approach aims at increasing the sensitivity of the method and hence the resulting Signal-to-Noise ratio (SNR) for a given total time interval. With prior knowledge of the shape of the object under study, a selective sparse k-space sampling can then be used to follow dynamic phenomena of transient systems, in this case the absorption of moisture by a cereal-based wafer material. Further improvement in the image quality is achieved when the un-sampled k-space points are replaced by those of the initial dry or the final wet sample acquired at the beginning and the end of the acquisition respectively when there are no acquisition time limitations

The effect of annealing on the elastoplastic and viscoelastic responses of isotactic polypropylene

Observations are reported on isotactic polypropylene (i) in a series of tensile tests with a constant strain rate on specimens annealed for 24 h at various temperatures in the range from 110 to 150 C and (ii) in two series of creep tests in the sub-yield region of deformation on samples not subjected to thermal treatment and on specimens annealed at 140 C. A model is developed for the elastoplastic and nonlinear viscoelastic responses of semicrystalline polymers. A polymer is treated an equivalent transient network of macromolecules bridged by junctions (physical cross-links, entanglements and lamellar blocks). The network is assumed to be highly heterogeneous, and it is thought of as an ensemble of meso-regions with different activation energies for separation of strands from temporary nodes. The elastoplastic behavior is modelled as sliding of meso-domains with respect to each other driven by mechanical factors. The viscoelastic response is attributed to detachment of active strands from temporary junctions and attachment of dangling chains to the network. Constitutive equations for isothermal uniaxial deformation are derived by using the laws of thermodynamics. Adjustable parameters in the stress-strain relations are found by fitting the experimental data.Comment: 29 pages, 14 figure

The effect of draw ratio on the mechanical properties and crystalline structure of single polymer polypropylene composites

The properties of self-reinforced single polymer composites produced by the Leeds hot compaction process are highly dependent on the compaction temperature as well as the constituent oriented elements used to produce the compacted sheets. In this paper, the variation in tensile mechanical properties of uniaxial hot compacted sheets manufactured from drawn polypropylene (PP) tapes with change in compaction temperature have been investigated, for a range of different draw ratio tapes. It is shown that there is a measureable difference between the optimum compaction temperatures required for obtaining the highest modulus and strength in the compacted sheets. The compaction temperature required to achieve the maximum tensile modulus was seen to increase with increasing draw ratio. The compaction temperature to obtain the maximum tensile strength was found to be both independent of the draw ratio and a few degrees higher than that for obtaining the maximum modulus. Peak modulus and peak tensile strength was shown to be dependent on the draw ratio of the drawn tape. Differential scanning calorimetry measurements on the compacted sheets were also performed in order to investigate the change in crystalline structure with compaction temperature and draw ratio. This has shown that the changes in structure within the oriented phase (i.e. tapes) during the compaction process itself are directly related to the final properties of the hot compacted sheets

Single-Polymer Composites (SPCs) : Status and Future Trends

Preparation, properties and applications of single-polymer composites (SPCs), representing an emerging family within the polymeric composite materials, have been surveyed. SPCs were classified in respect to their composition (one- and two-constituents), and preforms (non-consolidated and consolidated). SPCs composed of amorphous or semicrystalline matrices and semicrystalline reinforcements were considered. Methods to widen the temperature difference between the matrix- and reinforcement-giving materials of the same polymer (one-constituent) or same polymer type (two-constituent approach) have been introduced and discussed. Special attention was paid to the unsolved questions related to the interface/interphase in SPCs. It was emphasized that the development of SPCs is fuelled by the need of engineering parts in different applications which have low density and “ultimate” recyclability (i.e. reprocessing via remelting). Recent development of SPCs is supported by novel preform preparation, consolidation and production possibilities