Freezing of tilapia fillets in an air blast freezer

This paper explores the numerical simulation of freezing tilapia fillets of five different geometries, which are the slab, elliptical, disc, spherical and cylindrical shapes, in an air blast freezer. The air velocities and temperatures inside the freezer are varied in the simulation to determine the freezing times and energy consumptions for freezing the tilapia fillets of different shapes. The results show that the cylindrical-shaped fillet has the longest freezing time and also required the most energy for freezing. The slab-shaped fillet has the shortest freezing time, but the spherical-shaped fillet requires the least energy to freeze. The simulation is also applied to a case study to compare the processing rate, energy consumption and the cost of freezing the fillets of different shapes. The freezing cost for a tray of spherical-shaped fillet is the lowest among all.     

Evolutionary Computing on Consumer Graphics Hardware

We propose implementing a parallel EA on consumer graphics cards, which we can find in many PCs. This lets more people use our parallel algorithm to solve large-scale, real-world problems such as data mining. Parallel evolutionary algorithms run on consumer-grade graphics hardware achieve better execution times than ordinary evolutionary algorithms and offer greater accessibility than those run on high-performance computers     

The K-pulse and E-pulse

The relationship between the K-pulse and the E-pulse is considered. Conditions are derived whereby the two waveforms differ, at most, by a multiplicative constant.     

MR imaging of the brain: comparison of gradient-echo and spin-echo pulse sequences

OBJECTIVE: Gradient-echo pulse sequences can reduce imaging time and decrease motion artifacts. If gradient-echo pulse sequences are shown to be comparable to spin-echo sequences in MR imaging of the brain, then gradient-echo imaging can be valuable for examining critically ill, anxious, or uncooperative patients and can increase patient throughput. The purpose of this study was to prospectively compare one fast multiplanar spoiled gradient-recalled acquisition in the steady state (GRASS) (FMPSPGR) sequence with one conventional T1-weighted spin-echo sequence to determine the reliability of the FMPSPGR sequence for detecting cerebral lesions. SUBJECTS AND METHODS: Fifty-one patients with 142 cranial lesions, including brain tumors, infarction, infection, and noninflammatory lesions, were examined. Forty-two unenhanced and 39 contrast-enhanced FMPSPGR (113-240/2.6-3.6/90 degrees/4 [TR/TE/flip angle/acquisitions]) and spin-echo T1-weighted (400-579/11-12/90 degrees/2) MR images of the head were obtained with a 1.5-T system. The visibility, margination, and extent of the lesions; image quality; contrast; and artifacts were qualitatively and quantitatively compared. RESULTS: Supratentorial lesions were more conspicuous on the unenhanced FMPSPGR images because of the higher signal-to-noise ratio of the normal brain resulting in higher lesion contrast. The higher contrast-to-noise ratio of neoplasms on the contrast-enhanced spin-echo images was not found to be significant in the independent qualitative analysis. The conspicuity and extent of other lesions evaluated with the two pulse sequences were not significantly different for either the unenhanced or the contrast-enhanced studies. Vascular pulsation artifacts were significantly reduced on the contrast-enhanced FMPSPGR images. Susceptibility and chemical-shift phase-cancellation artifacts were more pronounced on the FMPSPGR images. CONCLUSION: The FMPSPGR sequence provides high-quality images with fewer vascular pulsation artifacts three to four times faster than the spin-echo sequence. The FMPSPGR sequence can reliably show intracranial lesions and can substitute for the T1-weighted spin-echo sequence in routine brain imaging.     

Relationship between nuclear graphite moderator brick bore profile measurement and irradiation-induced dimensional change

A stress analysis for a hypothetical nuclear graphite moderator brick is presented, considering dimensional and other property changes due to fast neutron irradiation, to illustrate the relationship between the change in moderator brick bore profile and dimensional change of the material. The results give the stresses and deformations of the brick during operation and at shutdown, with the effect of irradiation creep on the deformation of the brick also considered. The analyses provide information useful to reactor designers and operators for planning graphite monitoring campaigns.     

Mining Evolving Data Streams with Particle Filters

We propose a particle filter‐based learning method, PF‐LR, for learning logistic regression models from evolving data streams. The method inherently handles concept drifts in a data stream and is able to learn an  ensemble of logistic regression models with particle filtering. A key feature of PF‐LR is that in its resampling, step particles are sampled from the ones that maximize the classification accuracy on the current data batch. Our experiments show that PF‐LR gives good performance, even with relatively small batch sizes. It reacts to concept drifts quicker than conventional particle filters while being robust to noise. In addition, PF‐LR learns more accurate models and is more computationally efficient than the gradient descent method for learning logistic regression models. Furthermore, we evaluate PF‐LR on both synthetic and real data sets and find that PF‐LR outperforms some other state‐of‐the‐art streaming mining algorithms on most of the data sets tested.     

Multifunctional fluorescence correlation microscope for intracellular and microfluidic measurements

A modified fluorescence correlation microscope (FCM) was built on a commercial confocal laser scanning microscope (CLSM) by adding two sensitive detectors to perform fluorescence correlation spectroscopy (FCS). A single pinhole for both imaging and spectroscopy and a simple slider switch between the two modes thus facilitate the accurate positioning of the FCS observation volume after the confocal image acquisition. Due to the use of a single pinhole for CLSM and FCS the identity of imaged and spectroscopically observed positions is guaranteed. The presented FCM system has the capability to position the FCS observation volume at any point within the inner 30% of the field of view without loss in performance and in the inner 60% of the field of view with changes of FCS parameters of less than 10%. A single pinhole scheme for spatial fluorescence cross correlation spectroscopy performed on the FCM system is proposed to determine microfluidic flow angles. To show the applicability and versatility of the system, we measured the translational diffusion coefficients on the upper and lower membranes of Chinese hamster ovary cells. Two-photon excitation FCS was also realized by coupling a pulsed Ti: sapphire laser into the microscope and used for flow direction characterization in microchannels.     

Variable Temperature Blackbodies via Variable Conductance: Thermal Design,Modelling and Testing

This paper presents the overall design for large (\(\sim \)400 mm aperture) reference blackbody cavities currently under development at the Science and Technology Facilities Council Rutherford Appleton Laboratory Space Department (STFC RAL Space), in collaboration with the National Physical Laboratory (NPL). These blackbodies are designed to operate in vacuum over a temperature range from 160 K to 370 K, with an additional capability to operate at \(\sim \)100 K as a point of near-zero radiance. This is a challenging problem for a single blackbody. The novel thermal design presented in this paper enables one target that can physically achieve and operate successfully at both thermal extremes, whilst also meeting stringent temperature gradient requirements. The overall blackbody design is based upon a helium gas-gap heat switch and modified to allow for variable thermal conductance. The blackbody design consists of three main concentric cylinder components—an inner cavity (aluminium alloy), a radiation shield (aluminium) and an outer liquid nitrogen (\(\hbox {LN}_{2}\)) jacket (stainless steel). The internal surface of the cavity is the effective radiating surface. There is a helium gas interspace surrounding the radiation shield and enclosed by the \(\hbox {LN}_{2}\) jacket and the inner cavity. The blackbodies are now at a mature stage of development. In this paper, the overall design, focusing upon the thermal design solution, is detailed. This paper will also concern the full-scale prototype breadboard model, for which results on thermal stability, spatial gradients and other sensitivities will be presented.     

Integrated knowledge-based assembly sequence planning

This paper presents a novel approach and system for the automatic generation, selection and evaluation, optimisation, and simulation of assembly plans. The information and knowledge about a product and its assembly (e.g. assembly constraints, solid model and CAD database, heuristic rules) are described using a hybrid approach and model with numeric and symbolic representation. A new methodology is presented to generate all feasible assembly sequences of the product by reasoning and decomposing the feasible subassemblies, and representing them by the assembly Petri net modelling. Qualitative strategic constraints are then used to evaluate the feasible assembly sequences. In order to obtain a good assembly sequence, some quantitative criteria such as assembly time and cost, workstation number, operator number, and part priority index are applied to select the optimal assembly sequence. Based on DFA analysis, MTM time analysis, and assemblability analysis, estimates are made of the assembly time and cost of the product when each of these sequences is used. A knowledge-based system KAPSS has been developed to achieve the integration of generation, selection evaluation, and visualisation of the assembly sequences.