894 resultados para Oxyacetylene welding and cutting


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Camptosema grandiflorum Benth., belonging to Fabaceae, is a voluble climber plant native to Brazil. Plants bloom in autumn-winter, producing long and hanging inflorescences with showy red flowers, which are much visited by hummingbirds. The leaves are also attractive, composed by three leaflets. It can be propagated by seeds or cuttings, but both seed germination and cutting rooting percentages are very low. Thus, the objective of this work was to study the effect of different temperatures on seed germination and of different indolebutyric acid (IBA) concentrations on the rooting of cuttings of C. grandiflorum. The experiment was set up at the São Paulo State University, located in Jaboticabal, São Paulo State, Brazil. The germination study was conducted in an entirely randomized design with six different temperatures (constant at 20, 25, 30 and 35°C; and alternated at 20-30 and 25-35°C, with a photoperiod of 12 hours) and four replications of 25 seeds each, placed in plastic boxes with vermiculite. The percentage of germination and the speed germination index (SGI) were evaluated. An entirely randomized block design was adopted for the cutting rooting evaluation, with four IBA concentrations (0; 1,000; 2,000; and 3,000 mg kg-1) and five replications of ten cuttings each, comprising 200 cuttings. After 30 days from the beginning of the rooting experiment, data referring to rooting percentage, number and length of roots and dry weight of roots were collected. For the seed germination experiment, fastest germination and highest germination percentage (87%) were obtained when seeds were maintained under the constant temperature of 30°C. For the cutting experiment, the concentrations of 2,000 and 3,000 mg kg-1 of IBA promoted the highest rooting percentages (98.5 and 94.1%, respectively) and number of roots. There were no statistical differences among the IBA concentrations for length of roots and dry weight of roots.

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The effects of the moisture content of the raw material, extrusion temperature and screw speed on flavor retention, sensory acceptability and structure of corn grits extrudates flavored with isovaleraldehyde, ethyl butyrate and butyric acid were investigated. Higher temperature resulted in more expanded extrudates with lower density and cutting force, while higher moisture content increased ethyl butyrate retention. The most acceptable extrudates were those obtained with low moisture content, under conditions of high extrusion temperature and high screw speed, or low screw speed and low extrusion temperature, whereas the aroma intensity closest to the ideal was observed under conditions of low extrusion temperature and low moisture content of the raw material. © 2013 Elsevier Ltd.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The aim of this PhD thesis " Simulation Guided Navigation in cranio- maxillo- facial surgery : a new approach to Improve intraoperative three-dimensional accuracy and reproducibility during surgery ." was at the center of its attention the various applications of a method introduced by our School in 2010 and has as its theme the increase of interest of reproducibility of surgical programs through methods that in whole or in part are using intraoperative navigation. It was introduced in Orthognathic Surgery Validation a new method for the interventions carried out according to the method Simulation Guided Navigation in facial deformities ; was then analyzed the method of three-dimensional control of the osteotomies through the use of templates and cutting of plates using the method precontoured CAD -CAM and laser sintering . It was finally proceeded to introduce the method of piezonavigated surgery in the various branches of maxillofacial surgery . These studies have been subjected to validation processes and the results are presented .

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The aim of this study was to compare the effect of an anaesthetic combination given either intramuscularly (IM) or intranasally (IN) for castration of piglets. Forty piglets aged 4 to 7 days were randomly assigned to receive a mixture of ketamine 15 mg kg-1, climazolam 1.5 mg kg-1 and azaperone 1.0 mg kg-1, IN or IM, 10 minutes prior to castration. Physiological parameters were measured. Castration was videotaped for evaluation by 3 independent observers using a scoring system. Reaction and vocalization to the skin incision and cutting of spermatic cord was evaluated and scored (0 = no reaction, 16 = strong reaction). The IN group had a significantly higher (P < 0.01) castration score, compared to the IM group. There was an association between castration score and room temperature in the IN group (with temperatures below 18 "C associated with a higher castration scores (P < 0.001). Heart rate was significantly higher 10 minutes after castration in the IN group (P < 0.05). Respiratory rate was significantly higher in the IM group at time points -5, -1, 10, 20 and 30 (P < 0.05).The IN group was walking significantly (P < 0.0001) faster than the IM group. In conclusion, this combination provides effective anaesthesia for routine castration of newborn piglets when administered IM. IN administration provided shorter recovery times but had significantly higher castration scores.

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Sanidine separates from pumice of the early Miocene Peach Springs Tuff are concordantly dated at 18.5 ± 0.2 Ma by two isotopic techniques. The Peach Springs Tuff is the only known unit that can be correlated between isolated outcrops of Miocene strata from the central Mojave Desert of southeastern California to the western Colorado Plateau in Arizona, across five structural provinces, a distance of 350 km. Thus the age of the Peach Springs Tuff is important to structural and paleogeographic reconstructions of a large region. Biotite and sanidine separates from bulk samples of the Peach Springs Tuff from zones of welding and vapor-phase alteration have not produced consistent ages by the K-Ar method. Published ages of mineral separates from 17 localities ranged from 16.2 to 20.5 Ma. Discordant 40Ar/39Ar incremental release spectra were obtained for one biotite and two of the sanidine separates. Ages that correspond to the last gas increments are as old as 27 Ma. The 40Ar/39Ar incremental release determinations on sanidine separated from blocks of Peach Springs Tuff pumice yield ages of 18.3 ± 0.3 and 18.6 ± 0.4 Ma. Laser fusion measurements yield a mean age of 18.51 ± 0.10. The results suggest that sanidine and biotite K-Ar ages older than about 18.5 Ma are due to inherited Ar from pre-Tertiary contaminants, which likely were incorporated into the tuff during deposition. Sanidine K-Ar ages younger than 18 Ma probably indicate incomplete extraction of radiogenic 40Ar, whereas laser fusion dates of biotite and hornblende younger than 18 Ma likely are due to postdepositional alteration. Laser fusion ages as high as 19.01 Ma on biotite grains from pumice suggest that minerals from pre-Tertiary country rocks also were incorporated in the magma chamber.

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Agriculture is the back borne of the economy of Tanzania and its main objective is to ensure food security and eradication of rural poverty through the promotion of production systems, technologies and practices that are environmental sound (Tanzania National Environmental Policy, 1999). However, this has not been achieved due to rapid land degradation, which has consequently lead to massive soil loss, decline in crop yields, disruption of water resources and the destruction of the natural resources in general. This report highlights the extent to which agricultural related activities like agronomic and cultural practices such as use of fire for preparation of farms and cutting of trees to meet villagers’ needs have devastating effect on the quality of the environment. Besides these observed difficulties this paper argued that as the survival, well being and future of the Uluguru and Usambara people it is essential to provide continuous training to farmers, so that they know how best to continue farming and harvesting forest products on a sustainable basis without causing much harm to the environment. Most of all this paper recommends the introduction of Ngolo cultivation technology on steep slopes of Usambara and Uluguru mountains in order to enhance the conservation of the environment.

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"Compiled and edited by": 1921-24, L.B. Mackenzie, H.S. Card; 1926-32, H.S. Card; 1938-41, "re-edited by" Stuart Plumley; 1943- "completely revised and re-edited by" T.B. Jefferson.

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Developing a means of predicting tool life has been and continues to be a focus of much research effort. A common experience in attempting to replicate such efforts is an inability to achieve the levels of agreement between theory and practice of the original researcher or to extrapolate the work to different materials or cutting conditions to those originally used. This thesis sets out to examine why most equations or models when replicated do not give good agreements. One reason which was found is that researchers in wear prediction, their predictions are limited because they generally fail to properly identify the nature of wear mechanisms operative in their study. Also they fail to identify or recognise factors having a significant influence on wear such as bar diameter. Also in this research the similarities and differences between the two processes of single point turning and drilling are examined through a series of tests. A literature survey was undertaken in wear and wear prediction. As a result it was found that there was a paucity in information and research in the work of drilling as compared to the turning operation. This was extended to the lack of standards that exist for the drilling operation. One reason for this scarcity in information on drilling is due to the complexity of the drilling and the tool geometry of the drill. In the comparative drilling and turning tests performed in this work, the same tool material; HSS, and similar work material was used in order to eliminate the differences which may occur due to this factor. Results of the tests were evaluated and compared for the two operations and SEM photographs were taken for the chips produced. Specific test results were obtained for the cutting temperatures and forces of the tool. It was found that cutting temperature is influenced by various factors like tool geometry and cutting speed, and the temperature itself influenced the tool wear and wear mechanisms that act on the tool. It was found and proven that bar diameter influences the temperature, a factor not considered previously.

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The manufacturing industry faces many challenges such as reducing time-to-market and cutting costs. In order to meet these increasing demands, effective methods are need to support the early product development stages by bridging the gap of communicating early design ideas and the evaluation of manufacturing performance. This paper introduces methods of linking design and manufacturing domains using disparate technologies. The combined technologies include knowledge management supporting for product lifecycle management systems, Enterprise Resource Planning (ERP) systems, aggregate process planning systems, workflow management and data exchange formats. A case study has been used to demonstrate the use of these technologies, illustrated by adding manufacturing knowledge to generate alternative early process plan which are in turn used by an ERP system to obtain and optimise a rough-cut capacity plan. Copyright © 2010 Inderscience Enterprises Ltd.

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Theoretical research and specific surface area analysis of nitrogen adsorption indicated that a lot of structural micropores exist in sepiolite minerals fibers. However, the microporous size, existing form, and the distribution relationship between microporous structures were not proved yet. In this paper, the section TEM samples of nanofibers were prepared on the basis of the metal embedding and cutting technique, and the inner structure of sepiolite nanofibers was observed by TEM. The results showed that sepiolite fibers have multiplayer structure similar to concentric circles, and many micropores with the size of about 2–5 nm are normal and parallel to the -axis. The reason for the previously mentioned phenomenon was explained by using BET analysis and X-ray diffraction analysis results.

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The mechanical behaviour and performance of a ductile iron component is highly dependent on the local variations in solidification conditions during the casting process. Here we show a framework which combine a previously developed closed chain of simulations for cast components with a micro-scale Finite Element Method (FEM) simulation of the behaviour and performance of the microstructure. A casting process simulation, including modelling of solidification and mechanical material characterization, provides the basis for a macro-scale FEM analysis of the component. A critical region is identified to which the micro-scale FEM simulation of a representative microstructure, generated using X-ray tomography, is applied. The mechanical behaviour of the different microstructural phases are determined using a surrogate model based optimisation routine and experimental data. It is discussed that the approach enables a link between solidification- and microstructure-models and simulations of as well component as microstructural behaviour, and can contribute with new understanding regarding the behaviour and performance of different microstructural phases and morphologies in industrial ductile iron components in service.

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Mechanical harmonic transmissions are relatively new kind of drives having several unusual features. For example, they can provide reduction ratio up to 500:1 in one stage, have very small teeth module compared to conventional drives and very large number of teeth (up to 1000) on a flexible gear. If for conventional drives manufacturing methods are well-developed, fabrication of large size harmonic drives presents a challenge. For example, how to fabricate a thin shell of 1.7m in diameter and wall thickness of 30mm having high precision external teeth at one end and internal splines at the other end? It is so flexible that conventional fabrication methods become unsuitable. In this paper special fabrication methods are discussed that can be used for manufacturing of large size harmonic drive components. They include electro-slag welding and refining, the use of special expandable devices to locate and hold a flexible gear, welding peripheral parts of disks with wear resistant materials with subsequent machining and others. These fabrication methods proved to be effective and harmonic drives built with the use of these innovative technologies have been installed on heavy metallurgical equipment and successfully tested.

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The LiteSteel Beam (LSB) is a new hollow flange section developed by OneSteel Australian Tube Mills using their patented dual electric resistance welding and automated continuous roll-forming technologies. It has a unique geometry consisting of torsionally rigid rectangular hollow flanges and a relatively slender web. It has found increasing popularity in residential, industrial and commercial buildings as flexural members. The LSB is considerably lighter than traditional hot-rolled steel beams and provides both structural and construction efficiencies. However, the LSB flexural members are subjected to a relatively new lateral distortional buckling mode, which reduces their member moment capacities. Unlike the commonly observed lateral torsional buckling of steel beams, the lateral distortional buckling of LSBs is characterised by simultaneous lateral defection, twist and cross sectional change due to web distortion. The current design rules in AS/NZS 4600 (SA, 2005) for flexural members subject to lateral distortional buckling were found to be conservative by about 8% in the inelastic buckling region. Therefore, a new design rule was developed for LSBs subject to lateral distortional buckling based on finite element analyses of LSBs. The effect of section geometry was then considered and several geometrical parameters were used to develop an advanced set of design rules. This paper presents the details of the finite element analyses and the design curve development for hollow flange sections subject to lateral distortional buckling.

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Ecological sustainable development (ESD), defined as that which meets the needs of the present without compromising the ability of future generations to meet their own needs, has much to offer in enhancing the quality of life of people and maintaining the environment for future generations by reducing the pollution of water, air and land, minimizing the destruction of irreplaceable ecosystems and cutting down the amount of toxic materials released. However, there is still much to do to achieve full implementation world-wide. This paper reports on three factors-design, attitudes and financial constraints - that are likely barriers to the implementation of ESD within the built environment in Australian industry. A postal questionnaire survey is described aimed at soliciting views on detailed aspects of the factors. This shows that ESD in the Australian built environment has also not been successfully implemented. The main reason is found to be due to the perceived costs involved - the cost of using environmental materials being a predominant factor. The design of ESD, being more sophisticated, also is perceived as involving stakeholders in more expense. There also appears to be a lack of knowledge and a lack of specialised and interdisciplinary design teams available in the Australian context.