EMERGENCY REPAIRS TO THE MAIN BREAKWATER OF CALSHOT HARBOUR ON TRISTAN DA CUNHA ISLAND

The breakwater at Tristan da Cunha suffered structural damage during heavy seas that battered the island during winter 2010 (June and August). The damage was of such a nature that emergency repairs had to be designed and constructed before the onset of the next winter season. The damage entailed the loss of primary armour units (3.5t dolosse) at the head of the western breakwater exposing the under-layer rock as well as some slight movement of the end section of the crest slab (cap). Further damage to the breakwater head (130m offshore in 6m water depth) was reported one month later; with the crest slab being lifted further by approximately 500mm. The construction methodology during the emergency repair design process, laboratory validation and onsite construction is covered in this manuscript.

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Is flow velocity a significant parameter in flood damage modelling?

Natural Hazards and Earth System Science ◽

10.5194/nhess-9-1679-2009 ◽

2009 ◽

Vol 9 (5) ◽

pp. 1679-1692 ◽

Cited By ~ 135

Author(s):

H. Kreibich ◽

K. Piroth ◽

I. Seifert ◽

H. Maiwald ◽

U. Kunert ◽

...

Keyword(s):

Flow Velocity ◽

Water Depth ◽

Structural Damage ◽

Residential Buildings ◽

Flood Damage ◽

Damage Models ◽

Damage Modelling ◽

Impact Parameters ◽

A Minor ◽

The Impact

Abstract. Flow velocity is generally presumed to influence flood damage. However, this influence is hardly quantified and virtually no damage models take it into account. Therefore, the influences of flow velocity, water depth and combinations of these two impact parameters on various types of flood damage were investigated in five communities affected by the Elbe catchment flood in Germany in 2002. 2-D hydraulic models with high to medium spatial resolutions were used to calculate the impact parameters at the sites in which damage occurred. A significant influence of flow velocity on structural damage, particularly on roads, could be shown in contrast to a minor influence on monetary losses and business interruption. Forecasts of structural damage to road infrastructure should be based on flow velocity alone. The energy head is suggested as a suitable flood impact parameter for reliable forecasting of structural damage to residential buildings above a critical impact level of 2 m of energy head or water depth. However, general consideration of flow velocity in flood damage modelling, particularly for estimating monetary loss, cannot be recommended.

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INFLUENCE OF THE WATER DISTRIBUTION UNIFORMITY AND IRRIGATION DEPTH ON THE YIELD OF IRRIGATED BEAN CROP

Irriga ◽

10.15809/irriga.2009v14n4p458-469 ◽

2009 ◽

Vol 14 (4) ◽

pp. 458-469 ◽

Cited By ~ 1

Author(s):

Everardo C. Mantovani ◽

Gregório G. Faccioli ◽

Brauliro Gonçalves Leal ◽

Antonio Alves Soares ◽

Luis Claudio Costa ◽

...

Keyword(s):

Water Depth ◽

Water Distribution ◽

Irrigation System ◽

Winter Season ◽

Sprinkler Irrigation ◽

Field Capacity ◽

Uniformity Coefficient ◽

Irrigation Depth ◽

Distribution Uniformity ◽

Bean Crop

INFLUENCE OF THE WATER DISTRIBUTION UNIFORMITY AND IRRIGATION DEPTH ON THE YIELD OF IRRIGATED BEAN CROP Everardo C. Mantovani1; Gregório G. Faccioli2; Brauliro Gonçalves Leal3;Antônio Alves Soares1; Luis Cláudio Costa1; Paulo Sérgio L. Freitas4 1Departamento de Engenharia Agrícola, Universidade Federal de Viçosa, MG [email protected]úcleo de Estudos e Pesquisas do Nordeste, Universidade Federal de Sergipe, São Cristovão, SE3Intec Consultoria e Assessoria Ltda, Viçosa, MG4Departamento de Agronomia, Universidade Estadual de Maringá, Maringá, PR 1 ABSCTRACT This study aimed to evaluate the influence of the water distribution uniformity and three irrigation depths on the production variables for the bean crop, using a conventional sprinkler irrigation system, during the winter season. The treatments consisted of three irrigation depths and two uniformity levels of water distribution represented by the Christiansen uniformity coefficient (CUC). In the treatments L1A and L1B a sufficient water depth was applied to raise the soil water content to field capacity. The distribution uniformities (CUCs) were higher and lower than 80%, respectively. In treatments L2A and L3A, and L2B and L3B, the applied water depths corresponded to 50% and 150% of that applied to the LIA treatment. Because of rainfall events until the sampling date, no significant differences at 5% probability were found among treatments, when the variables were: leaf number, leaf area and dry matter. The F test for the contrast among the treatments with high and low uniformity was significant at 5% probability, when using 50% replacement of the water depth required by the crop. Significant differences were observed at 5% probability for pod number per plant among the treatments, when using 150, 100 and 50% replacement of the water depth required by the crop KEYWORDS: irrigation uniformity, sprinkler irrigation, yield. MANTOVANI, E. C.; FACCIOLI, G. G.; LEAL, B. G.; SOARES,A. A.; COSTA, L. C.; FREITAS, P. S. L. INFLUÊNCIA DA UNIFORMIDADE DE DISTRIBUIÇÃO DE ÁGUA E LÂMINA DE IRRIGAÇÃO NA PRODUTIVIDADE DO FEIJÃO 2 RESUMO O presente trabalho teve como objetivo avaliar a influência da uniformidade de distribuição de água e de três lâminas de irrigação nas variáveis de produção da cultura do feijão, utilizando um sistema de aspersão convencional, no período de inverno. Os tratamentos constaram de três lâminas de irrigação e dois níveis de uniformidade de distribuição de água, representados pelo coeficiente de uniformidade de Christiansen (CUC). Nos tratamentos L1A e L1B foi aplicada uma lâmina de água suficiente para elevar a umidade do solo à capacidade de campo, com uniformidade de distribuição (CUC) maior e menor que 80%, respectivamente. Nos tratamentos L2A e L3A, e L2B e L3B as lâminas aplicadas foram, respectivamente, 50% e 150% da lâmina aplicada no tratamento L1A. Não existiram diferenças significativas, a 5% de probabilidade, nos tratamentos para seguintes variáveis: número de folhas, área foliar e matéria seca, em razão das chuvas ocorridas até a data da amostragem. O teste F para o contraste entre os tratamentos de alta e baixa uniformidade com 50% de reposição da lâmina requerida pela cultura foi significativo a 5% de probabilidade. Observou-se diferenças significativas, a 5% de probabilidade entre os tratamentos com 150, 100 e 50% de reposição da lâmina requerida pela cultura, para o número de vagens por planta. UNITERMOS: Uniformidade de irrigação, irrigação por aspersão, produtividade.

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Measurement and Evaluation of Mooring Cable Forces During Storm Events on the Evergreen Point Floating Bridge: Lake Washington, Washington State

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1845-04 ◽

2003 ◽

Vol 1845 (1) ◽

pp. 28-36

Author(s):

Scott T. Peterson ◽

David I. McLean ◽

Mark Anderson ◽

David G. Pollock

Keyword(s):

Return Period ◽

Structural Damage ◽

Winter Season ◽

Storm Event ◽

Storm Events ◽

Lake Washington ◽

Mooring Cable ◽

Floating Bridge ◽

Measurement And Evaluation ◽

Cable Forces

On January 20, 1993, the Evergreen Point Floating Bridge incurred structural damage at two mooring cables and at various other locations during a storm event of approximately the 20-year return period magnitude. The two mooring cables damaged were the shorter and stiffer cables located at the ends of the bridge and were likely damaged because of load attraction issues. To improve the performance of the floating bridge during storms, special replacement cables were installed after the 1993 storm near the areas where cable distress was noted. Measurements of cable forces were made during the winter season of 2001–2002 to evaluate the effectiveness of the replacement mooring cables. From the experimental measurements, it was found that the special replacement mooring cables have reduced the load attraction at the shorter end cables with respect to cable tension values reported for the pre-retrofit analysis. However, the measurements indicate that the replacement cables continue to attract loads between 65% and 80% higher than those measured at the longer and more flexible cables located near the midspan of the floating bridge during storm events of approximately the 1-year return period magnitude.

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Study of a Rock-Ramp Fish Pass with Staggered Emergent Square Obstacles

Water ◽

10.3390/w13091175 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1175

Author(s):

Flavia Cavalcanti Miranda ◽

Ludovic Cassan ◽

Pascale Laurens ◽

Tien Dung Tran

Keyword(s):

Velocity Field ◽

Kinetic Energy ◽

Turbulent Kinetic Energy ◽

Design Process ◽

Water Depth ◽

Numerical Study ◽

Flow Characteristics ◽

Fish Passage ◽

Lower Velocity ◽

Water Depths

A rock-ramp fish passage with square obstacles was experimentally and numerically studied in this work with the objective of investigating in detail the hydraulic behind such fishways and to evaluate the importance of the shape of the obstacles. The LES and VOF methods were used for the simulations, and for the measurements, shadowgraphy and ADV were applied. Two different validations were successfully performed. In the first one, the experimental and numerical results of a chosen case were compared in detail. In the second validation, the focus was given to the stage-discharge. Following the validation, a numerical study was carried out to point out the differences in the flow characteristics from a configuration with square and circular obstacles. The discharge was nearly the same for both configurations, which implies different water depths. The results showed a lower velocity field, lower turbulent kinetic energy, and lower lateral fluctuations for the configuration with square blocks, which indicated a better passability for this geometry. However, it also presented a higher water depth, which led to a less attractive discharge. The differences in the flow generated in the two configurations indicated that the shape is an important modifiable parameter to be considered in the design process.

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Evaluation of single-electron movies of glutamine synthetase molecules

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075191 ◽

1983 ◽

Vol 41 ◽

pp. 280-281

Author(s):

W. Kunath ◽

E. Zeitler ◽

M. Kessel

Keyword(s):

Electron Microscope ◽

Glutamine Synthetase ◽

Electron Irradiation ◽

Structural Damage ◽

Structural Changes ◽

Single Electron ◽

Continuous Series ◽

Digital Recording ◽

Recording Device ◽

Low Exposure

The features of digital recording of a continuous series (movie) of singleelectron TV frames are reported. The technique is used to investigate structural changes in negatively stained glutamine synthetase molecules (GS) during electron irradiation and, as an ultimate goal, to look for the molecules' “undamaged” structure, say, after a 1 e/Å2 dose.The TV frame of fig. la shows an image of 5 glutamine synthetase molecules exposed to 1/150 e/Å2. Every single electron is recorded as a unit signal in a 256 ×256 field. The extremely low exposure of a single TV frame as dictated by the single-electron recording device including the electron microscope requires accumulation of 150 TV frames into one frame (fig. lb) thus achieving a reasonable compromise between the conflicting aspects of exposure time per frame of 3 sec. vs. object drift of less than 1 Å, and exposure per frame of 1 e/Å2 vs. rate of structural damage.

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Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053188 ◽

1982 ◽

Vol 40 ◽

pp. 78-79

Author(s):

Kenneth H. Downing ◽

Robert M. Glaeser

Keyword(s):

Electron Beam ◽

Fatty Acid ◽

Inelastic Scattering ◽

Temperature Dependence ◽

Structural Damage ◽

Direct Result ◽

Second Step ◽

Strong Temperature Dependence ◽

Electron Dose ◽

Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

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Modification of the Electron Microscope for Investigation of Fully Hydrated Biological Specimens

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100064001 ◽

1969 ◽

Vol 27 ◽

pp. 418-419 ◽

Cited By ~ 2

Author(s):

R. C. Moretz ◽

D. F. Parsons

Keyword(s):

Electron Beam ◽

Electron Microscope ◽

Structural Damage ◽

Lower Percentage ◽

Vacuum Drying ◽

Total Removal ◽

Total Absence ◽

Biological Studies ◽

Electron Microscopes ◽

Beam Damage

Short lifetime or total absence of electron diffraction of ordered biological specimens is an indication that the specimen undergoes extensive molecular structural damage in the electron microscope. The specimen damage is due to the interaction of the electron beam (40-100 kV) with the specimen and the total removal of water from the structure by vacuum drying. The lower percentage of inelastic scattering at 1 MeV makes it possible to minimize the beam damage to the specimen. The elimination of vacuum drying by modification of the electron microscope is expected to allow more meaningful investigations of biological specimens at 100 kV until 1 MeV electron microscopes become more readily available. One modification, two-film microchambers, has been explored for both biological and non-biological studies.

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Slow-scan CCD cameras and low-dose High-Resolution Electron Microscopy: Direct and quantitative

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100169791 ◽

1994 ◽

Vol 52 ◽

pp. 412-413

Author(s):

M. Pan

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Structural Damage ◽

Low Dose ◽

Dynamic Range ◽

High Resolution Electron Microscopy ◽

Operating Conditions ◽

Digital Data ◽

Ccd Cameras ◽

Resolution Electron

It has been known for many years that materials such as zeolites, polymers, and biological specimens have crystalline structures that are vulnerable to electron beam irradiation. This radiation damage severely restrains the use of high resolution electron microscopy (HREM). As a result, structural characterization of these materials using HREM techniques becomes difficult and challenging. The emergence of slow-scan CCD cameras in recent years has made it possible to record high resolution (∽2Å) structural images with low beam intensity before any apparent structural damage occurs. Among the many ideal properties of slow-scan CCD cameras, the low readout noise and digital recording allow for low-dose HREM to be carried out in an efficient and quantitative way. For example, the image quality (or resolution) can be readily evaluated on-line at the microscope and this information can then be used to optimize the operating conditions, thus ensuring that high quality images are recorded. Since slow-scan CCD cameras output (undistorted) digital data within the large dynamic range (103-104), they are ideal for quantitative electron diffraction and microscopy.

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