Flow boiling heat transfer of R134a and R245fa in a 2.3 mm tube

This paper presents new experimental flow boiling heat transfer results in micro-scale tubes. The experimental data were obtained in a horizontal 2.3 mm I.D stainless steel tube with heating length of 464 mm, R134a and R245fa as working fluids, mass velocities ranging from 50 to 700 kg m(-2) s(-1), heat flux from 5 to 55 kW m(-2), exit saturation temperatures of 22, 31 and 41 degrees C, and vapor qualities ranging from 0.05 to 0.99. Flow pattern characterization was also performed from images obtained by high-speed filming. Heat transfer coefficient results from 1 to 14 kW m(-2) K(-1) were measured. It was found that the heat transfer coefficient is a strong function of heat flux, mass velocity and vapor quality. The experimental data were compared against ten flow boiling predictive methods from the literature. Liu and Winterton [3], Zhang et al. [5] and Saitoh et al. [6] worked best for both fluids, capturing most of the experimental heat transfer trends. (C) 2010 Elsevier Ltd. All rights reserved.

Slip ratio in dispersed viscous oil-water pipe flow

In this article, dispersed flow of viscous oil and water is investigated. The experimental work was performed in a 26.2-mm-i.d. 12-m-long horizontal glass pipe using water and oil (viscosity of 100 mPa s and density of 860 kg/m(3)) as test fluids. High-speed video recording and a new wire-mesh sensor based on capacitance (permittivity) measurements were used to characterize the flow. Furthermore, holdup data were obtained using quick-closing-valves technique (QCV). An interesting finding was the oil-water slip ratio greater than one for dispersed flow at high Reynolds number. Chordal phase fraction distribution diagrams and images of the holdup distribution over the pipe cross-section obtained via wire-mesh sensor indicated a significant amount of water near to the pipe wall for the three different dispersed flow patterns identified in this study: oil-in-water homogeneous dispersion (o/w H), oil-in-water non-homogeneous dispersion (o/w NH) and Dual continuous (Do/w & Dw/o). The phase slip might be explained by the existence of a water film surrounding the homogeneous mixture of oil-in-water in a hidrofilic-oilfobic pipe. (C) 2010 Elsevier Inc. All rights reserved.

Robust model predictive controller with output feedback and target tracking

A model predictive controller (MPC) is proposed, which is robustly stable for some classes of model uncertainty and to unknown disturbances. It is considered as the case of open-loop stable systems, where only the inputs and controlled outputs are measured. It is assumed that the controller will work in a scenario where target tracking is also required. Here, it is extended to the nominal infinite horizon MPC with output feedback. The method considers an extended cost function that can be made globally convergent for any finite input horizon considered for the uncertain system. The method is based on the explicit inclusion of cost contracting constraints in the control problem. The controller considers the output feedback case through a non-minimal state-space model that is built using past output measurements and past input increments. The application of the robust output feedback MPC is illustrated through the simulation of a low-order multivariable system.

Effects of sewage sludge amendment on the properties of two Brazilian oxisols and their humic acids

The effect of sewage sludge (SS) amendment on the general properties of the top layers of a sandy and a clayey oxisols and on the nature of their humic acid (HA) fractions was evaluated by chemical and physico-chemical techniques. The amended soils, especially the sandy soil, benefited of SS amendment by increasing their pH to above neutrality and enhancing the contents of C, N, P, and Ca and cation exchange capacity. The SS-HA-like sample showed larger H and N contents and a greater aliphatic character and humification degree than the HAs isolated from non-amerided soils. The composition and structure of amended soil HAs were affected by SS application as a function of soil type and layer. In particular, N-containing groups and aliphatic structures of SS-HA-like sample appears to be partially incorporated in the amended soil HAs, and these effects were more evident in the HAs from the sandy oxisol. (C) 2007 Elsevier Ltd. All rights reserved.

CYP17 polymorphism and hot flushes in postmenopausal women

Objective To investigate the association between the CYP17 alpha gene polymorphism and hot flushes in postmenopausal women. Methods Ninety-three non-hysterectomized, postmenopausal women were enrolled in this study. Vasomotor symptoms were assessed at the baseline visit and based on information provided by each participant. The genotypic polymorphism of CYP17 alpha gene was analyzed by PCR-RFLP assay using genomic DNA isolated from peripheral blood lymphocytes. Results Thirty-six women reported hot flushes of mild intensity, 25 reported hot flushes of moderate intensity and 32 of severe intensity. There was no significant difference between the severity of hot flushes and the CYP17 genotype or allele frequencies, 0.58 and 0.67 respectively. No association was found between hot flush severity and the CYP17 allele (odds ratio = 1.17, p = 0.61). Conclusion The results of this study suggest that the CYP17 MspAI polymorphism was not significantly associated with an increased risk of reporting hot flushes. At the World Congress on Menopause in Madrid, May 2008, Dr Massad-Costa was awarded the Robert Greenblatt Prize for Basic Science for the study reported in this paper.

A comparison of anterior adhesive areas and secretions in Troglocephalus rhinobatidis and Neoheterocotyle rhinobatidis (Monogenea : Monocotylidae) from the gills of the shovelnose ray, Rhinobatos typus (Rhinobatidae)

This study continues the collection of data on the anterior adhesive areas and secretions of monopisthocotylean monogenean (flatworm) parasites and begins an investigation of their phylogenetic usefulness. Here, two species of parasitic worms from an elasmobranch, Troglocephalus rhinobatidis (Monocotylidae: Dasybatotreminae) and Neoheterocotyle rhinobatidis (Monocotylidae: Heterocotylinae), are compared and contrasted. It has been suggested in recent literature that these two taxa are more closely related than is currently recognised. Our data support this view. Both species have multiple apertures on the ventral anterior margin through which adhesive is secreted. Two types of secretion exit from multiple adjacent duct endings terminating in each aperture: rod-shaped (S1) and spherical-shaped (S2) bodies. S1 bodies of both species show nano-banding of similar size and are membrane bound. Ultrastructure of the glands, ducts, duct endings and secreted adhesive is similar for both species, but aperture shape differs. Away from the adhesive areas, tegumental inclusions are found to differ between the two species and another, apparently non-adhesive, secretion is found in N. rhinobatidis.

A new genus of viviparous gyrodactylid (Monogenea) from the Great Barrier Reef, Australia with descriptions of seven new species

Acanthoplacatus gen. nov., a new genus of viviparous gyrodactylid, is described from the rns and skin of siganid fishes from the Great Barrier Reef, Australia. The genus is characterized by a muscular, tube-like haptor with 16 marginal hooks on the posterior margin. The ventral lobe of the haptor is located anteriorly relative to the dorsal lobe and contains a pair of hamuli and a ventral bar with posteriorly-projecting ventral bar membrane. A dorsal bar is absent. Five pairs of posterior gland cells surround the posterior terminations of the gut. The male copulatory organ is a muscular, non-eversible bulb with several spines around the distal opening. Species of Acanthoplacatus have a bilateral excretory system consisting of six pairs of flame cells and a pair of excretory bladders. Seven new species are described: Acanthoplacatus adlardi sp. nov. and A. amplihamus sp. nov. from Siganus punctatus (Forster, 1801), A. brauni sp. nov. from S. corallinus (Valenciennes, 1835), A. parvihamus sp. nov. from S. vulpinus (Schlegel and Mueller, 1845), A. puelli sp. nov. from S. puellus Schlegel, 1852, A. shieldsi sp. nov. from S. lineatus (Valenciennes, 1835) and A. sigani sp. nov. from S. fuscescens (Houttuyn, 1782). Species can be discriminated by shape and size of the hamuli, marginal hooks and ventral bar and by male copulatory organ sclerite morphology. Three species (A. brauni sp. nov., A. shieldsi sp. nov. and A. sigani sp. nov.) were assessed for seasonal variation of sclerite size. Ten of thirteen morphological characters showed seasonal variation in size for at least one of the species. The characters were longer in winter except dorsal root tissue cap width. Only one character, marginal hook length, showed significant seasonal variation for all three species. Species of Acanthoplacatus were observed to attach using only the marginal hooks and the role of hamuli in attachment is unclear. The dorsal rn of the host is the preferred site for most species but the anal fin, caudal fin and body surfaces are preferred by some species. Prevalences for species range from 57 to 100%.

SAR imaging of buried objects from MoM modelled scattered field

Synthetic aperture radar (SAR) images of resonant buried objects are modelled in the presence of ground surface clutter. The method of moments (MoM) is used to model scattered fields from a resonant buried conductor and clutter is modelled as a bivariant Gaussian distribution. A diffraction stack SAR imaging technique is applied to the ultra-wideband waveforms to give a bipolar signal image. A number of examples have been computed to illustrate the combined effects of SAR processing with resonant targets and clutter. SAR images of different targets show differences which may facilitate target identification. To maximise the peak signal-to-clutter ratio, an image correlation technique is applied and the results are shown.

The calibre of the Foramen of Panizza in Crocodylus porosus is variable and under adrenergic control

The foramen of Panizza is located within the outflow tract of the crocodilian heart, between the left and right aortas. It has been suggested that the foremen of Panizza has a variable calibre, which could explain the profound changes in the distribution of flows and pressure profiles recorded in the right and left aortas. We investigated this possibility using a modified in-situ perfused heart preparation in combination with isolated strip preparations from the outflow tract. In the perfused heart preparation, bolus injections of adrenaline increased the resistance in the foramen of Panizza, indicating a decrease in its diameter. Isolated strip preparations from the outflow tract showed a concentration-dependent increase in tension in response to adrenaline, while vasoactive intestinal polypeptide caused a relaxation in adrenaline pre-contracted strip preparations. We propose that an increase in the diameter of the foremen of Panizza may be important during pulmonary to systemic shunts to allow blood to flow from the left to right aorta (reverse foramen flow) in order to supply the carotid and coronary arteries. During non-shunting conditions, a constricted foramen may prevent excess flow from the right to left aorta during diastole.

High resolution 3-D imaging via multi-pass SAR

Spaceborne/airborne synthetic aperture radar (SAR) systems provide high resolution two-dimensional terrain imagery. The paper proposes a technique for combining multiple SAR images, acquired on flight paths slightly separated in the elevation direction, to generate high resolution three-dimensional imagery. The technique could be viewed as an extension to interferometric SAR (InSAR) in that it generates topographic imagery with an additional dimension of resolution. The 3-D multi-pass SAR imaging system is typically characterised by a relatively short ambiguity length in the elevation direction. To minimise the associated ambiguities we exploit the relative phase information within the set of images to track the terrain landscape. The SAR images are then coherently combined, via a nonuniform DFT, over a narrow (in elevation) volume centred on the 'dominant' terrain ground plane. The paper includes a detailed description of the technique, background theory, including achievable resolution, and the results of an experimental study.

Three-dimensional space-borne synthetic aperture radar (SAR) imaging with multiple pass processing

Three-dimensional (3D) synthetic aperture radar (SAR) imaging via multiple-pass processing is an extension of interferometric SAR imaging. It exploits more than two flight passes to achieve a desired resolution in elevation. In this paper, a novel approach is developed to reconstruct a 3D space-borne SAR image with multiple-pass processing. It involves image registration, phase correction and elevational imaging. An image model matching is developed for multiple image registration, an eigenvector method is proposed for the phase correction and the elevational imaging is conducted using a Fourier transform or a super-resolution method for enhancement of elevational resolution. 3D SAR images are obtained by processing simulated data and real data from the first European Remote Sensing satellite (ERS-1) with the proposed approaches.

Physical aging of amorphous fructose

Physical aging of amorphous anhydrous fructose at temperature 5 degreesC and at 22 degreesC was studied using differential scanning calorimetry (DSC). The dynamic glass transitions temperature, T-g0 for unaged samples was 16 degreesC and 13.3 degreesC for heating rate of 10 degreesC/min and 1 degreesC/min, respectively. The fictive temperature, T-f0 for unaged samples calculated by Richardson and Savill method was 12 degreesC, which is close to the dynamic value obtained from the lower DSC heating rate. The fictive temperature T-f of the aged fructose glasses at temperatures both below and above the transition region was fitted well by a non-exponential decay function (Williams-Watts form). Aging above the transition region (22 degreesC) for 18 d increased both the dynamic glass transition temperature T and the fictive temperature T-f. However, aging below the transition region (5 degreesC) for I d increased the dynamic glass transition temperature T-g but decreased the fictive temperature T-f.

Effects of intravenous injection of Clostridium perfringens type D epsilon toxin in calves

In cattle, a neurological lesion similar to that produced in sheep and goats by Clostridium perfringens type D enterotoxaemia has been reported. However, no causal relationship has been established between this disease and the lesion in cattle. The effects of single and multiple intravenous injections of epsilon toxin in three calves aged 6 months were studied. A further calf was inoculated intravenously with saline solution and used as a control. Epsilon toxin invariably produced neurological signs within 2-60 min of the end of the injection process. Clinical signs consisted of loss of consciousness, recumbency, convulsions, paddling, opisthotonus, hyperaesthesia and dyspnoea. Gross changes consisted of severe acute pulmonary oedema, which was particularly marked in the interlobular septa. The histological lesions consisted of intra-alveolar and interstitial oedema of the lung and variable degrees of perivascular proteinaceous oedema in the internal capsule, thalamus and cerebellar white matter. No clinical or post-mortem changes were observed in the control calf. These results show that calves are susceptible to the intravenous injection of epsilon toxin, and that they can show at least some of the histological lesions produced in sheep and goats by this toxin. (C) 2002 Harcourt Publishers Ltd.

Critical comparison of Julius Kruttschnitt Mineral Research Centre (JKMRC) blast fragmentation models

Blast fragmentation can have a significant impact on the profitability of a mine. An optimum run of mine (ROM) size distribution is required to maximise the performance of downstream processes. If this fragmentation size distribution can be modelled and controlled, the operation will have made a significant advancement towards improving its performance. Blast fragmentation modelling is an important step in Mine to Mill™ optimisation. It allows the estimation of blast fragmentation distributions for a number of different rock mass, blast geometry, and explosive parameters. These distributions can then be modelled in downstream mining and milling processes to determine the optimum blast design. When a blast hole is detonated rock breakage occurs in two different stress regions - compressive and tensile. In the-first region, compressive stress waves form a 'crushed zone' directly adjacent to the blast hole. The second region, termed the 'cracked zone', occurs outside the crush one. The widely used Kuz-Ram model does not recognise these two blast regions. In the Kuz-Ram model the mean fragment size from the blast is approximated and is then used to estimate the remaining size distribution. Experience has shown that this model predicts the coarse end reasonably accurately, but it can significantly underestimate the amount of fines generated. As part of the Australian Mineral Industries Research Association (AMIRA) P483A Mine to Mill™ project, the Two-Component Model (TCM) and Crush Zone Model (CZM), developed by the Julius Kruttschnitt Mineral Research Centre (JKMRC), were compared and evaluated to measured ROM fragmentation distributions. An important criteria for this comparison was the variation of model results from measured ROM in the-fine to intermediate section (1-100 mm) of the fragmentation curve. This region of the distribution is important for Mine to Mill™ optimisation. The comparison of modelled and Split ROM fragmentation distributions has been conducted in harder ores (UCS greater than 80 MPa). Further work involves modelling softer ores. The comparisons will be continued with future site surveys to increase confidence in the comparison of the CZM and TCM to Split results. Stochastic fragmentation modelling will then be conducted to take into account variation of input parameters. A window of possible fragmentation distributions can be compared to those obtained by Split . Following this work, an improved fragmentation model will be developed in response to these findings.

A model updating technique based on FRFs for damped structures

Model updating methods often neglect that in fact all physical structures are damped. Such simplification relies on the structural modelling approach, although it compromises the accuracy of the predictions of the structural dynamic behaviour. In the present work, the authors address the problem of finite element (FE) model updating based on measured frequency response functions (FRFs), considering damping. The proposed procedure is based upon the complex experimental data, which contains information related to the damped FE model parameters and presents the advantage of requiring no prior knowledge about the damping matrix structure or its content, only demanding the definition of the damping type. Numerical simulations are performed in order to establish the applicability of the proposed damped FE model updating technique and its results are discussed in terms of the correlation between the simulated experimental complex FRFs and the ones obtained from the updated FE model.