滑坡和泥石流致灾条件叠合技术及风险分析-以川藏公路然乌至鲁朗段为例

As one part of national road No. 318, Sichuan-Tibet (Chengdu-Lasha) Highway is one of traffic life lines connecting Tibet municipality to the inland, which is very important to the economic development of Tibet. In addition, it is still an important national defence routeway, with extremely important strategic position on maintaining the stability and solidarity of Tibet municipality and consolidating national defence. Particular geological condition, terrain and landform condition and hydrometeorological condition induce large-scale debris flows and landslides (including landslips) and the like geological hazards frequently occur along the highway. High frequency geological hazards not only result in high casualties and a great property loss, but also block traffic at every turn, obstructing the Sichuan-Tibet highway seriously. On the basis of considerable engineering geological investigation and analysis to the relative studying achievements of predecessors, it is found that one of the dominating reason incurring landslides or debris flows again and again in a place is that abundant loose materials are accumulated in valleys and slopes along the highway. Taking landslides' and debris flows along Ranwu-Lulang section of Sichuan-Tibet highway as studying objects, the sources and cause of formation of loose accumulation materials in the studying area are analyzed in detail, the major hazard-inducing conditions, hazard, dynamic risk, prediction of susceptibility degree of landslides and debris flows, and the relations between landslides and debris flows and various hazard-inducing conditions are systematically researched in this paper. All of these will provide scientific foundation for the future highway renovating and reducing and preventing geological hazards. For the purpose of quantitatively analyzing landslide and debris flow hazards, the conception of entropy and information entropy are extended, the conception of geological hazard entropy is brought forward, and relevant mathematics model is built. Additionally, a new approach for the dynamic risk analysis of landslide and debris flow is put forward based on the dynamic characteristics of the hazard of hazard-inducings and the vulnerability of hazard-bearings. The formation of landslide and debris flow is a non-linear process, which is synthetically affected by various factors, and whose formation mechanics is extremely complex. Aiming at this question, a muli-factors classifying and overlapping technique is brought forward on the basis of engineering geomechanics meta-synthesis (EGMS) thought and approach, and relevant mathematics model is also built to predict the susceptibility degree of landslide or debris flow. The example analysis result proves the validity of this thought and approach. To studying the problem that whether the formation and space distribution of landslides and debris flows are controlled by one or several hazard-inducing conditions, the theme graphics of landslides and debris flows hazard and various hazard-inducing conditions are overlapped to determine the relationship between hazard and hazard-inducing conditions. On this basis, the semi-quantitative engineering zonation of the studying area is carried out. In addition, the overlapping analysis method of the hazard-indue ing conditions of landslides and debris flows based on "digital graphics system" is advanced to orderly organize and effectively manage the spatial and attributive data of hazard and hazard-inducing conditions theme graphics, and to realize the effectively combination of graphics, images and figures.

Spatial vision in the purple sea urchin Strongylocentrotus purpuratus (Echinoidea).

Recent evidence that echinoids of the genus Echinometra have moderate visual acuity that appears to be mediated by their spines screening off-axis light suggests that the urchin Strongylocentrotus purpuratus, with its higher spine density, may have even more acute spatial vision. We analyzed the movements of 39 specimens of S. purpuratus after they were placed in the center of a featureless tank containing a round, black target that had an angular diameter of 6.5 deg. or 10 deg. (solid angles of 0.01 sr and 0.024 sr, respectively). An average orientation vector for each urchin was determined by testing the animal four times, with the target placed successively at bearings of 0 deg., 90 deg., 180 deg. and 270 deg. (relative to magnetic east). The urchins showed no significant unimodal or axial orientation relative to any non-target feature of the environment or relative to the changing position of the 6.5 deg. target. However, the urchins were strongly axially oriented relative to the changing position of the 10 deg. target (mean axis from -1 to 179 deg.; 95% confidence interval +/- 12 deg.; P<0.001, Moore's non-parametric Hotelling's test), with 10 of the 20 urchins tested against that target choosing an average bearing within 10 deg. of either the target center or its opposite direction (two would be expected by chance). In addition, the average length of the 20 target-normalized bearings for the 10 deg. target (each the vector sum of the bearings for the four trials) were far higher than would be expected by chance (P<10(-10); Monte Carlo simulation), showing that each urchin, whether it moved towards or away from the target, did so with high consistency. These results strongly suggest that S. purpuratus detected the 10 deg. target, responding either by approaching it or fleeing it. Given that the urchins did not appear to respond to the 6.5 deg. target, it is likely that the 10 deg. target was close to the minimum detectable size for this species. Interestingly, measurements of the spine density of the regions of the test that faced horizontally predicted a similar visual resolution (8.3+/-0.5 deg. for the interambulacrum and 11+/-0.54 deg. for the ambulacrum). The function of this relatively low, but functional, acuity - on par with that of the chambered Nautilus and the horseshoe crab - is unclear but, given the bimodal response, is likely to be related to both shelter seeking and predator avoidance.

Risk of dislocation using large- vs. small-diameter femoral heads in total hip arthroplasty.

BACKGROUND: Dislocation remains a difficult problem in total hip arthroplasty. Large-diameter femoral heads may lower the incidence of dislocation by enhancing the jump distance and decreasing impingement, but their performance against small-diameter heads has not been assessed. This study compared the mid-term radiographic and functional outcomes of two matched cohorts of patients undergoing total hip arthroplasty who had a high pre-operative risk for dislocation and who received either small-diameter (26- or 28-millimeters) or large-diameter (≥36-millimeters) femoral heads. METHODS: All patients who received large-diameter heads (≥36-millimeter) between 2002 and 2005, and who had pre-operative risk factors for dislocation, were identified in the institution's joint registry. Forty-one patients (52 hips) who received large-diameter heads were identified, and these patients were matched to 48 patients (52 hips) in the registry who received small-diameter femoral heads. RESULTS: At mean final follow-up of 62 months (range, 49 to 101 months), both groups achieved excellent functional outcomes as measured by Harris Hip scores, with slightly better final scores in the large-diameter group (90 vs. 83 points). No patient showed any radiographic signs of loosening. No patient dislocated in the large-diameter femoral head group; the smaller-diameter group had a greater rate of dislocation (3.8%, 2 out of 52). CONCLUSIONS: Large-diameter femoral head articulations may reduce dislocation rates in patients who have a high pre-operative risk for dislocation while providing the same functional improvements and safety as small-diameter bearings.

An integrated multi-sensor data fusion algorithm and autopilot iImplementation in an uninhabited surface craft

Unmanned surface vehicles (USVs) are able to accomplish difficult and challenging tasks both in civilian and defence sectors without endangering human lives. Their ability to work round the clock makes them well-suited for matters that demand immediate attention. These issues include but not limited to mines countermeasures, measuring the extent of an oil spill and locating the source of a chemical discharge. A number of USV programmes have emerged in the last decade for a variety of aforementioned purposes. Springer USV is one such research project highlighted in this paper. The intention herein is to report results emanating from data acquired from experiments on the Springer vessel whilst testing its advanced navigation, guidance and control (NGC) subsystems. The algorithms developed for these systems are based on soft-computing methodologies. A novel form of data fusion navigation algorithm has been developed and integrated with a modified optimal controller. Experimental results are presented and analysed for various scenarios including single and multiple waypoints tracking and fixed and time-varying reference bearings. It is demonstrated that the proposed NGC system provides promising results despite the presence of modelling uncertainty and external disturbances.

Microabrasion-corrosion of cast CoCrMo alloy in simulated body fluids

Wear and corrosion of metal-on-metal hip replacements results in wear debris and metal-ion release in vivo, which may subsequently cause pain and hypersensitivity for patients. Retrieved metal-on-metal hip replacements have revealed that two-body sliding wear and three-body abrasive wear are the predominant wear mechanisms. However, there is a lack of understanding of the combined effects of wear/corrosion, especially the effect of abrasion-corrosion.

This study investigates the sliding-corrosion and abrasion-corrosion performance of a cast CoCrMo alloy in simulated hip joint environments using a microabrasion rig integrated with an electrochemical cell. Tests have been conducted in 0.9% NaCl, phosphate buffered saline solution, 25% and 50% bovine serum solutions with 0 or 1 g cm(-3) SiC at 37 degrees C. Experimental results reveal that under abrasion-corrosion test conditions, the presence of proteins increased the total specific wear rate. Conversely, electrochemical noise measurements indicated that the average anodic current levels were appreciably lower for the proteinaceous solutions when compared with the inorganic solutions. A severely deformed nanocrystalline layer was identified immediately below the worn surface for both proteinaceous and inorganic solutions. The layer is formed by a recrystallisation process and/or a strain-induced phase transformation that occurs during microabrasion-corrosion. (C) 2008 Elsevier Ltd. All rights reserved.

Micro- and Nano-scale Tribo-Corrosion of Cast CoCrMo

Previous studies have established that some of the wear damage seen on cast CoCrMo joint surface is caused by entrained third-body hard particles. In this study, wet-cell micro-indentation and nano-scratch tests have been carried out with the direct aim of simulating wear damage induced by single abrasive particles entrained between the surfaces of cast CoCrMo hip implants. In situ electrochemical current noise measurements were uniquely performed to detect and study the wear-induced corrosion as well as the repassivation kinetics under the micro-/nano-scale tribological process. A mathematical model has been explored for the CoCrMo repassivation kinetics after surface oxide film rupture. Greater insights into the nature of the CoCrMo micro-/nano-scale wear-corrosion mechanisms and deformation processes are determined, including the identification of slip band formation, matrix/carbide deformation, nanocrystalline structure formation and strain-induced phase transformation. The electrochemical current noise provides evidence of instantaneous transient corrosion activity at the wearing surface resulting from partial oxide rupturing and stripping, concurrent with the indent/scratch.

An EPID-based method for comprehensive verification of gantry, EPID and the MLC carriage positional accuracy in Varian linacs during arc treatments

Background

]In modern radiotherapy, it is crucial to monitor the performance of all linac components including gantry, collimation system and electronic portal imaging device (EPID) during arc deliveries. In this study, a simple EPID-based measurement method has been introduced in conjunction with an algorithm to investigate the stability of these systems during arc treatments with the aim of ensuring the accuracy of linac mechanical performance.

The Varian EPID sag, gantry sag, changes in source-to-detector distance (SDD), EPID and collimator skewness, EPID tilt, and the sag in MLC carriages as a result of linac rotation were separately investigated by acquisition of EPID images of a simple phantom comprised of 5 ball-bearings during arc delivery. A fast and robust software package was developed for automated analysis of image data. Twelve Varian linacs of different models were investigated.

The average EPID sag was within 1 mm for all tested linacs. All machines showed less than 1 mm gantry sag. Changes in SDD values were within 1.7 mm except for three linacs of one centre which were within 9 mm. Values of EPID skewness and tilt were negligible in all tested linacs. The maximum sag in MLC leaf bank assemblies was around 1 mm. The EPID sag showed a considerable improvement in TrueBeam linacs.

The methodology and software developed in this study provide a simple tool for effective investigation of the behaviour of linac components with gantry rotation. It is reproducible and accurate and can be easily performed as a routine test in clinics.

Tipologia, instalação, funcionamento e manutenção dos diversos tipos de aparelhos de apoio em obras de arte

Trabalho Final para a obtenção do grau de Mestre em Engenharia Civil

Projecto de uma passagem superior à autoestrada 10

Trabalho de Projecto para obtenção do grau de Mestre em Engenharia Civil

Aparelhos de apoio em pontes: vida útil e procedimentos de substituição

Dissertação de Natureza Científica para obtenção do grau de Mestre em Engenharia Civil Perfil Estruturas

Pontes integrais: estado da arte

Dissertação para obtenção do grau de mestre em Engenharia Civil

Otimização Energética do Sistema de Refrigeração da máquina de impregnar ZELL

Esta dissertação teve como objetivo fundamental a otimização energética do sistema de refrigeração da máquina de impregnar tela ZELL e, como objetivo adicional, a avaliação da qualidade da água do circuito, justificada pela acentuada degradação dos rolos devido à corrosão provocada pela recirculação da água de arrefecimento. Inicialmente fez-se o levantamento de informações do processo produtivo para caracterizar o funcionamento do sistema de refrigeração, tendo-se selecionado duas telas de poliéster designadas neste estudo por P1 e P2 e, também, uma tela de nylon designada por N. Foram efetuados ensaios, um para cada tela, para a atual temperatura de setpoint da água à saída da torre de arrefecimento (30ºC). Realizou-se outro ensaio para a tela N mas com uma temperatura de setpoint de 37ºC, ao qual se chamou N37. Deste modo, determinou-se as potências térmicas removidas pela água de refrigeração e as potências térmicas perdidas por radiação e por convecção, tendo-se verificado que na generalidade dos rolos as referências P1 e P2 apresentam valores mais elevados. Em termos percentuais, a potência térmica removida pela água de refrigeração nos grupos tratores 1 e 3 e no conjunto de rolos de R1 a R29 corresponde a 48%, 10% e 70%, respetivamente. Com a avaliação às necessidades de arrefecimento da máquina ZELL, confirmou-se que os caudais atuais de refrigeração dos rolos garantem condições, mais que suficientes, de funcionamento dos rolamentos. Assim sendo, fez-se uma análise no sentido da diminuição do caudal total que passou de 10,25 L/s para 7,65 L/s. Considerando esta redução, determinou-se o caudal de ar húmido a ser introduzido na torre de arrefecimento. O valor determinado foi de 4,6 m3ar húmido/s, o que corresponde a uma redução de cerca de 32% em relação ao caudal atual que é de 6,8 m3ar húmido/s. Com os resultados das análises efetuadas à água do circuito de refrigeração, concluiu-se que a água de reposição e a água de recirculação possuem má qualidade para uso na generalidade dos sistemas de refrigeração, principalmente devido aos elevados valores de concentração de ferro e condutividade elétrica, responsáveis pela intensificação da corrosão no interior dos rolos.

Brock University Coat of Arms

The armorial bearings for Brock University, or more simply the University Coat of Arms, or crest, was designed in a large part by Presdent Gibson, assisted by other members of the Board of Governors (A preliminary design can be seen here). The Coat of Arms was granted to Brock University on March 17th, 1965. The Coat of Arms consist of an eagle, taken from General Brock’s own arms, displayed against a scarlet background - one of the official colours of Brock University. Immediately above it on a chief argent is displayed a maple-leaf (for Canada), a scallop shell (from the Lincoln and Welland regiment), and a trillium (for the province of Ontario). An open book fronts the eagle representing learning and knowledge. The crest itself is made up of a torch symbolizing learning, surrounded by a serpent for wisdom, with two calumet or North American pipes of peace, to symbolize Canada, friendship and agreement. The supporters consist of a beaver on the dexter side, emblematic of Canada and representing work and industry in learning. On the sinister side, a brock or badger (also in commemoration of General Brock) represents tenacity of purpose. The motto 'Surgite' is visible just below the arms.

Discours sociaux et aliénation dans deux romans de Gary Victor

L’aliénation est une problématique clé de la littérature haïtienne. Ce thème, abordé à de nombreuses reprises, est renouvelé dans les œuvres de l’écrivain Gary Victor, plus particulièrement dans les romans À l’angle des rues parallèles et Je sais quand Dieu vient se promener dans mon jardin. Ce mémoire a pour but d’étudier l’aliénation due à l’assimilation des différents discours qui circulent dans la société. Victor ne fait pas que montrer l’aliénation collective et individuelle ainsi que les différents mécanismes qui provoquent cette «folie». Il campe ses récits dans un univers chaotique où les modalités interdiscursives de la représentation des lieux et des milieux viennent renforcer cette impression d’aliénation quasi généralisée, et les personnages les plus fous apparaissent finalement comme étant les plus lucides. Des notions empruntées à la sociocritique nous ont servi de cadre théorique pour cette recherche. Le mémoire est composé de cinq chapitres. Les quatre premiers procèdent à l’analyse des discours qui sont présentés comme les sources de l’aliénation des personnages. Le chapitre un est consacré aux discours qui découlent de la société de consommation, qui ne s’appliquent plus uniquement aux objets, mais bien à la gestion des relations interpersonnelles. Le second chapitre se penche sur la question des croyances religieuses, que ce soient les croyances traditionnelles indigènes ou la religion catholique, et montre comment elles peuvent être potentiellement dangereuses pour ceux et celles qui sont trop crédules et comment elles peuvent devenir une arme pour les personnes malintentionnées. Le troisième chapitre étudie la façon dont les discours politiques et historiques sont devenus des lieux de référence pernicieux pour la société haïtienne et la manière dont les personnes au pouvoir les utilisent afin de manipuler le peuple. Le quatrième chapitre aborde les effets pervers des différents discours des savoirs en sciences humaines, plus particulièrement ceux de la philosophie et de la psychanalyse. Il montre les conséquences désastreuses qu’ils peuvent entraîner lorsqu’ils sont transformés en principes immuables. Le dernier chapitre analyse quelques modalités de cette représentation inédite de l’aliénation. Des lieux hostiles, des personnages violents ainsi que l’utilisation de références littéraires et cinématographiques marquant l’imaginaire social font partie des techniques employées par Victor. Ce chapitre fait ressortir également les différentes figures qui traduisent la résistance à cet univers démentiel. Notre lecture des romans de Victor conduit à une réflexion sur la définition du roman populaire, en lien avec la modernité telle que définie par Alexis Nouss. D’après ce qui se dégage de l’œuvre de Gary Victor, ce genre, objet de nombreuses critiques et défini comme servant uniquement au simple divertissement des lecteurs, peut aussi aider à prévenir les dérives des sociétés en perte de repères.

Le corps fantomatique dans Le Ravissement de Lol V. Stein de Marguerite Duras et La Maison étrangère d'Élise Turcotte

Depuis la valorisation du corps comme site identitaire et comme langage autre dans la théorisation de l’écriture au féminin des années 1970, les représentations du corps, notamment du corps féminin, occupent la scène romanesque jusqu’à aujourd’hui. Dans cette perspective, le présent mémoire s’intéresse au corps fantomatique des héroïnes du Ravissement de Lol V. Stein de Marguerite Duras et de La Maison étrangère d’Élise Turcotte. Le corps se fait littéralement hantise chez Duras et Turcotte : il est marqué d’absence, d’étrangeté, de fatigue et d’errance, ne trouvant plus de lieu d’être ni de repères à la suite d’un événement « traumatique », dans le cas de Lol, ou à la suite d’une séparation, dans celui d’Élisabeth. Les protagonistes sont sous l’emprise d’un sentiment d’étrangeté qui spectralise le corps en introduisant un décalage dans le rapport à soi et à autrui. Ce sentiment est causé en partie par une mémoire défaillante qui fragmente leur identité. C’est par un travail mémoriel que Lol V. Stein et Élisabeth tenteront de résoudre la hantise de leur histoire individuelle et familiale. Le texte fait écho à la corporalité fantomatique – mise en scène selon diverses représentations du corps dématérialisé – en se spectralisant à son tour par l’inscription des « blancs » dans l’écriture. Le processus d’effacement des corps sera mis en parallèle avec une spatio-temporalité elle aussi marquée par la hantise du passé. La spectralité apparaît, dans le récit contemporain au féminin, pour témoigner d’une identité (cor)rompue par la rupture ; celle-ci devient prétexte à une réflexion sur la manière d’habiter son corps et d’un être-au-monde à repenser.