201 resultados para materials control

em University of Queensland eSpace - Australia


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The National Health and Medical Research Council has funded Professor Wayne Hall (University of Queensland) and Professor Simon Chapman (University of Sydney) for three years 2006-2008, to research aspects of the future of tobacco control, particularly in nations with advanced tobacco control programs like Australia. Dr Coral Gartner (UQ) and Ms Becky Freeman (USyd) are also working on the project. The University of Queensland's eSpace site provides links to papers and data appendices produced by the University of Queensland team on the project. Materials relevant to this project produced by the University of Sydney group are available at the link provided.

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The fabrication of heavy-duty printer heads involves a great deal of grinding work. Previously in the printer manufacturing industry, four grinding procedures were manually conducted in four grinding machines, respectively. The productivity of the whole grinding process was low due to the long loading time. Also, the machine floor space occupation was large because of the four separate grinding machines. The manual operation also caused inconsistent quality. This paper reports the system and process development of a highly integrated and automated high-speed grinding system for printer heads. The developed system, which is believed to be the first of its kind, not only produces printer heads of consistently good quality, but also significantly reduces the cycle time and machine floor space occupation.

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We describe remarkable success in controlling dengue vectors, Aedes aegypti (L.) and Aedes albopictus (Skuse), in 6 communes with 11,675 households and 49,647 people in the northern provinces of Haiphong, Hung Yen, and Nam Dinh in Vietnam. The communes were selected for high-frequency use of large outdoor concrete tanks and wells. These were found to be the source of 49.6-98.4% of Ae. aegypti larvae, which were amenable to treatment with local Mesocyclops, mainly M. woutersi Van der Velde, M. aspericornis (Daday) and M. thermocyclopoides Harada. Knowledge, attitude, and practice surveys were performed to determine whether the communities viewed dengue and dengue hemorrhagic fever as a serious health threat; to determine their knowledge of the etiology, attitudes, and practices regarding control methods including Mesocyclops; and to determine their receptivity to various information methods. On the basis of the knowledge, attitude, and practice data, the community-based dengue control program comprised a system of local leaders, health volunteer teachers, and schoolchildren, supported by health professionals. Recycling of discards for economic gain was enhanced, where appropriate, and this, plus 37 clean-up campaigns, removed small containers unsuitable for Mesocyclops treatment. A previously successful eradication at Phan Boi village (Hung Yen province) was extended to 7 other villages forming Di Su commune (1,750 households) in the current study. Complete control was also achieved in Nghia Hiep (Hung Yen province) and in Xuan Phong (Nam Dinh province); control efficacy was greater than or equal to 99.7% in the other 3 communes (Lac Vien in Haiphong, Nghia Dong, and Xuan Kien in Nam Dinh). Although tanks and wells were the key container types of Ae. aegypti productivity, discarded materials were the source of 51% of the standing crop of Ae. albopictus. Aedes albopictus larvae were eliminated from the 3 Nam Dinh communes, and 86-98% control was achieved in the other 3 communes. Variable dengue attack rates made the clinical and serological comparison of control and untreated communes problematic, but these data indicate that clinical surveillance by itself is inadequate to monitor dengue transmission.

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A method is proposed for determining the optimal placement and controller design for multiple distributed actuators to reduce the vibrations of flexible structures. In particular, application of piezoceramic patches to a horizontally-slewing single-link flexible manipulator modeled using the assumed modes method is investigated. The optimization method uses simulated annealing and allows placement of any number of distributed actuators of unequal length, although piezoceramics of fixed equal lengths are used in the example. It also designs an linear-quadratic-regulator controller as part of the optimization procedure. The measures of performance used in the investigation to determine optimality are the total mass of the system and the time integral of the absolute value of the hub and tip position error. This study also varies the relative weightings for each of these performance measures to observe the effects on the controller designs and piezoceramic patch positions in the optimized solutions.

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Targeted treatment education for cancer patients has the potential to promote adjustment through assisting patients to participate in treatment decision making, comply with treatment regimens and cope more effectively with treatment side effects. A quasi-experimental longitudinal pre-test post-test and follow-up design was used to assess the effect of a patient education video about radiation therapy on patients' psychological distress, knowledge about radiation therapy, self-efficacy about coping with treatment and physical symptoms. Patients with head and neck (n = 26) and breast cancer (n = 66) were recruited into the study and allocated into control and intervention groups. No significant differences were found between the control and intervention groups on any of the outcome variables. However, patients in the intervention group reported high levels of satisfaction with the video and all reported that they would recommend the video to other patients preparing for radiation therapy. As well, 90% of patients in the intervention group reported that some or all of the information in the video was new to them. Education materials that have excellent face validity and that are well received by patients may fail to produce significant change using standard controlled study designs. Future research in this area may need to consider alternative paradigms for evaluating the helpfulness of such materials. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved.

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Adsorption of argon and nitrogen at their respective boiling points in cylindrical pores of MCM-41 type silica-like adsorbents is studied by means of a non-local density functional theory (NLDFT), which is modified to deal with amorphous solids. By matching the theoretical results of the pore filling pressure versus pore diameter against the experimental data, we arrive at a conclusion that the adsorption branch (rather than desorption) corresponds to the true thermodynamic equilibrium. If this is accepted, we derive the optimal values for the solid–fluid molecular parameters for the system amorphous silica–Ar and amorphous silica–N2, and at the same time we could derive reliably the specific surface area of non-porous and mesoporous silica-like adsorbents, without a recourse to the BET method. This method is then logically extended to describe the local adsorption isotherms of argon and nitrogen in silica-like pores, which are then used as the bases (kernel) to determine the pore size distribution. We test this with a number of adsorption isotherms on the MCM-41 samples, and the results are quite realistic and in excellent agreement with the XRD results, justifying the approach adopted in this paper.

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In this paper we apply a new method for the determination of surface area of carbonaceous materials, using the local surface excess isotherms obtained from the Grand Canonical Monte Carlo simulation and a concept of area distribution in terms of energy well-depth of solid–fluid interaction. The range of this well-depth considered in our GCMC simulation is from 10 to 100 K, which is wide enough to cover all carbon surfaces that we dealt with (for comparison, the well-depth for perfect graphite surface is about 58 K). Having the set of local surface excess isotherms and the differential area distribution, the overall adsorption isotherm can be obtained in an integral form. Thus, given the experimental data of nitrogen or argon adsorption on a carbon material, the differential area distribution can be obtained from the inversion process, using the regularization method. The total surface area is then obtained as the area of this distribution. We test this approach with a number of data in the literature, and compare our GCMC-surface area with that obtained from the classical BET method. In general, we find that the difference between these two surface areas is about 10%, indicating the need to reliably determine the surface area with a very consistent method. We, therefore, suggest the approach of this paper as an alternative to the BET method because of the long-recognized unrealistic assumptions used in the BET theory. Beside the surface area obtained by this method, it also provides information about the differential area distribution versus the well-depth. This information could be used as a microscopic finger-print of the carbon surface. It is expected that samples prepared from different precursors and different activation conditions will have distinct finger-prints. We illustrate this with Cabot BP120, 280 and 460 samples, and the differential area distributions obtained from the adsorption of argon at 77 K and nitrogen also at 77 K have exactly the same patterns, suggesting the characteristics of this carbon.

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Soldering alloys based oft the Sn-Cu alloy system are amongst the most favourable lead-free alternatives due to a range of attractive properties. Trace additions of Ni have been found to significantly improve the soldering characteristics of these alloys (reduced bridging etc.). This paper examines the mechanisms underlying the improvement in soldering properties of Sn-0.7 mass%Cu eutectic alloys modified with concentrations of Ni ranging front 0 to 1000 ppm. The alloys were investigated by thermal analysis during solidification, as well as optical/SEM microanalyses of fully solidified samples anti samples quenched during solidification. It is concluded that Ni additions dramatically alter the nucleation patterns and solidification behaviour of the Sn-Cu6Sn5 eutectic anti that these changes are related to the superior soldering characteristics of the Ni-modified Sn-0.7 mass%Cu alloys.

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Leptin and Y2 receptors on hypothalamic NPY neurons mediate leptin effects on energy homeostasis; however, their interaction in modulating osteoblast activity is not established. Here, direct testing of this possibility indicates distinct mechanisms of action for leptin anti-osteogenic and Y2(-/-) anabolic pathways in modulating bone formation. Introduction: Central enhancement of bone formation by hypothalamic neurons is observed in leptin-deficient oblob and Y2 receptor null mice. Similar elevation in central neuropeptide Y (NPY) expression and effects on osteoblast activity in these two models suggest a shared pathway between leptin and Y2 receptors in the central control of bone physiology. The aim of this study was to test whether the leptin and Y2 receptor pathways regulate bone by the same or distinct mechanisms. Materials and Methods: The interaction of concomitant leptin and Y2 receptor deficiency in controlling bone was examined in Y2(-/-) oblob double mutant mice, to determine whether leptin and Y2 receptor deficiency have additive effects. Interaction between leptin excess and Y2 receptor deletion was examined using recombinant adeno-associated viral vector overproduction of NPY (AAV-NPY) to produce weight gain and thus leptin excess in adult Y2(-/-) mice. Cancellous bone volume and bone cell function were assessed. Results: Osteoblast activity was comparably elevated in oblob, Y2(-/-), and Y2(-/-) oblob mice. However, greater bone resorption in oblob and Y2(-/-) oblob mice reduced cancellous bone volume compared with Y2(-/-). Both wildtype and Y2(-/-) AAV-NPY mice exhibited marked elevation of white adipose tissue accumulation and hence leptin expression, thereby reducing osteoblast activity. Despite this anti-osteogenic leptin effect in the obese AAV-NPY model, osteoblast activity in Y2(-/-) AAV-NPY mice remained significantly greater than in wildtype AAV-NPY mice. Conclusions: This study suggests that NPY is not a key regulator of the leptin-dependent osteoblast activity, because both the leptin-deficient stimulation of bone formation and the excess leptin inhibition of bone formation can occur in the presence of high hypothalamic NPY. The Y2(-/-) pathway acts consistently to stimulate bone formation; in contrast, leptin continues to suppress bone formation as circulating levels increase. As a result, they act increasingly in opposition as obesity becomes more marked. Thus, in the absence of leptin, the cancellous bone response to loss of Y2 receptor and leptin activity can not be distinguished. However, as leptin levels increase to physiological levels, distinct signaling pathways are revealed.

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Equilibrium adsorption and desorption in mesoporous adsorbents is considered on the basis of rigorous thermodynamic analysis, in which the curvature-dependent solid-fluid potential and the compressibility of the adsorbed phase are accounted for. The compressibility of the adsorbed phase is considered for the first time in the literature in the framework of a rigorous thermodynamic approach. Our model is a further development of continuum thermodynamic approaches proposed by Derjaguin and Broekhoff and de Boer, and it is based on a reference isotherm of a non-porous material having the same chemical structure as that of the pore wall. In this improved thermodynamic model, we incorporated a prescription for transforming the solid-fluid potential exerted by the flat reference surface to the potential inside cylindrical and spherical pores. We relax the assumption that the adsorbed film density is constant and equal to that of the saturated liquid. Instead, the density of the adsorbed fluid is allowed to vary over the adsorbed film thickness and is calculated by an equation of state. As a result, the model is capable to describe the adsorption-desorption reversibility in cylindrical pores having diameter less than 2 nm. The generalized thermodynamic model may be applied to the pore size characterization of mesoporous materials instead of much more time-consuming molecular approaches. (c) 2005 Elsevier B.V. All rights reserved.

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We report a simple but efficient method to prepare stable homogeneous suspensions containing monodispersed MgAl layered double hydroxide (LDH) nanoparticles that have wide promising applications in cellular drug ( gene) delivery, polymer/LDH nanocomposites, and LDH thin films for catalysis, gas separation, sensing, and electrochemical materials. This new method involves a fast coprecipitation followed by controlled hydrothermal treatment under different conditions and produces stable homogeneous LDH suspensions under variable hydrothermal treatment conditions. Moreover, the relationship between the LDH particle size and the hydrothermal treatment conditions ( time, temperature, and concentration) has been systematically investigated, which indicates that the LDH particle size can be precisely controlled between 40 and 300 nm by adjusting these conditions. The reproducibility of making the identical suspensions under identical conditions has been confirmed with a number of experiments. The dispersion of agglomerated LDH aggregates into individual LDH crystallites during the hydrothermal treatment has been further discussed. This method has also been successfully applied to preparing stable homogeneous LDH suspensions containing various other metal ions such as Ni2+, Fe2+, Fe3+, Co2+, Cd2+, and Gd3+ in the hydroxide layers and many inorganic anions such as Cl-, CO32-, NO3-, and SO42-.

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Highly ordered rodlike periodic mesoporous organosilicas (PMO) were successfully synthesized using 1.2-bis(trimethoxysilyl)ethane as an precursor and triblock copolymer P123 as a template at low acid concentration and in the presence of inorganic salts (KCl). The role of acid and salt as well as the effects of synthesis temperature and reactant mole ratio in the control of morphology and the formation of ordered mesostructure was systematically examined. It was found that the addition of inorganic salt can dramatically expand the range of the synthesis parameters to produce highly ordered PMO structure and improve the quality of PMO materials. The morphology of PMOs was significantly dependent on the induction time for precipitation. The uniform PMO rods can only be synthesized in a narrow range of acid and salt concentrations. The results also show that the optimized salt concentration (I M) and low acidity (0.167 M) were beneficial to the formation of not only highly ordered mesostructure but also rodlike morphology. Increasing acidity resulted in fast hydrolysis reaction and short rod or plate-like particles. Highly ordered rod can also be prepared at low temperature (35 degrees C) with high salt amount (1.5 M) or high temperature (45 degrees C) with low salt amount (0.5 M). Optimum reactant molar composition at 40 degrees C is 0.035P123:8KCl:1.34HCI:444H(2)O:1.0bis(trimethoxysilyl)ethane. Lower or higher SiO2/PI23 ratio led to the formation of uniform meso-macropores or pore-blocking effect. (c) 2005 Elsevier Inc. All rights reserved.

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