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Chávez, V.; Mendoza, E.; Ramírez, E., and Silva, R., 2017. Impact of inlet management on the resilience of a coastal lagoon: La Mancha, Veracruz, Mexico. In: Martinez, M.L.; Taramelli, A., and Silva, R. (eds.), Coastal Resilience: Exploring the Many Challenges from Different Viewpoints. Journal of Coastal Research, Special Issue No. 77, pp. 51-61. Coconut Creek (Florida), ISSN 0749-0208. The importance of conserving wetlands for their functions and services, has shown the need for adequate management practices, which take into consideration the vulnerability and resilience of these ecosystems. The lagoon of La Mancha, Veracruz, Mexico, is a Ramsar site, which in practice is empirically managed by local fishermen. To assess the vulnerability of this ecosystem, the erosion/accretion of the beach, inlet dynamics, the hydrodynamics of circulation patterns in the lagoon during winter storms, and the effects of anthropogenic activities were studied. Four topographic surveys were performed between 2013 and 2015. Complementarily, physicochemical parameters in the lagoon and at the inlet were registered in November 2014.The field data shows that the beach is resilient to the effects of winter storms, as long as sediment availability is not interrupted. The circulation patterns of the lagoon were obtained using a 2D non linear shallow water numerical model; the results indicate that the winds and waves can induce the opening and closing of the inlet. The governing force in the lagoon hydrodynamics is the tidal oscillation, as corroborated by the physicochemical parameters measured. The natural cycles of the system are altered by the local fishermen, who once or twice a year open the inlet of the lagoon. It was found that the environmental resilience of the estuarine-lagoon system is quite sensitive to the number of times and the season when the inlet is opened and that the anthropogenic interference is increasing the vulnerability of the ecosystem of La Mancha. [ABSTRACT FROM AUTHOR]

Sea chests are cavities built into a vessel's hull to aid the efficiency of pumping seawater into internal pipework systems. Sea chests and internal pipework are known hotspots for the accumulation of biofouling, and vessel biofouling is a major pathway for the introduction and spread of nonindigenous marine species. The use of preventive strategies to minimize biofouling within sea chests and internal pipework is difficult due to their structural complexity; therefore, reactive methods to manage the associated biosecurity risk are required. This review examines the efficacy, environmental considerations, and cost of different systems to reactively manage sea chest and internal pipework biofouling within operationally realistic time frames (<3 days) and identifies those that warrant further investigation. Physical removal systems with recapture capability should be developed for accessible areas (e.g., grates), as such systems provide an operational benefit to the vessel. For internal and inaccessible surfaces, the development of thermal systems, particularly steam systems, is encouraged as they offer broad-spectrum efficacy at obtainable temperatures and require relatively short exposure periods. Compared to chemical treatments, thermal treatments are less influenced by environmental variables (e.g., temperature, water chemistry) and regulatory constraints. [ABSTRACT FROM AUTHOR]

Purpose Biofouling of marine vessels results in significant operational costs, as well as the bio-security risk associated with the transport of marine pests. Biofouling is particularly rapid in sea-chest water intakes due to elevated temperatures and circulating flow. Inspection challenges are exacerbated, as sea chests are difficult to inspect and clean. This paper aims to present a method that utilises the flexibility and low-batch capabilities of additive manufacture to manufacture custom sea-chest inserts that eliminate circulating flow and increase the uniformity of shear stress distributions to enable more constant ablation of anti-biofouling coatings.Design/methodology/approach An automated design procedure has been developed to optimise sea-chest insert geometry to achieve desirable flow characteristics, while eliminating the necessity for support material in FDM manufacture – thereby significantly reducing build cost and time.Findings Numerical flow simulation confirms that the fluid-flow approximation is robust for optimising sea-chest insert geometry. Insert geometry can be manipulated to enable support-free additive manufacture; however, as the threshold angle for support-free manufacture increases, the set of feasible sea-chest aspect ratios decreases.Research limitations/implications The surface of revolution that defines the optimal insert geometry may result in features that are not compatible with additive manufacture constraints. An alternate geometry is proposed that may be more useful in practice without compromising anti-biofouling properties.Practical implications Marine sea-chest biofouling results in significant negative environmental and economic consequence. The method developed in this paper can reduce the negative impact of sea-chest biofouling.Social implications Marine sea-chest biofouling results in significant resource consumption and emissions. The method developed in this paper can reduce the negative impact of sea-chest biofouling.Originality/value The method presented in this paper provides an entirely original opportunity to utilise additive manufacture to mitigate the effects of marine biofouling. [ABSTRACT FROM AUTHOR]

Dewatering on the paper machine takes place by gravity, suction, pressing, and evaporation. Optimizing the operation of the vacuum system is important, since the electricity consumption of the vacuum pumps might be one-fifth of the total electricity consumption of the paper machine. Vacuum dewatering involves large volumes of air penetrating the web. The present study presents four sets of measured air flow rates useful for designing industrial equipment. The mass flux of air increases with increasing applied vacuum and decreases with increasing basis weight. Paper technological parameters, such as fiber size and fiber flexibility, also influence the mass flux. [ABSTRACT FROM AUTHOR]

Abstract: This study examined the efficacy of heated seawater for the treatment and remediation of fouled vessel sea chest habitats. In laboratory trials, three temperature regimes (37.5°C for 60min, 40°C for 30min and 42.5°C for 20min) were tested on a range of temperate taxa commonly found in sea chests. Field validation trials further assessed the efficacy of heat treatment within a replica sea chest environment. During laboratory trials, 100% mortality was achieved across all three treatments for the majority of taxa; the exceptions being the barnacle Elminius modestus and the oyster Crassostrea gigas. Temperature tolerance limits observed in the laboratory were successfully replicated under simulated sea chest conditions; however, a failure to achieve even heat distribution was an obstacle to achieving uniform mortality. This study provides guidance on the temperature/exposure parameters required for vessels plying temperate latitudes, and demonstrates that heated seawater has potential for controlling biofouling in vessel sea chests. [Copyright &y& Elsevier]

Abstract: During paper forming on a single-wire paper machine, i.e. a Fourdrinier or a hybrid paper machine, the pulp suspension is dewatered on a moving wire mainly through vacuum assisted devices (suction boxes). The dewatering process is supposed to occur by dead-end filtration under constant pressure as long as the fiber mat (filter cake) remains fully saturated with water. A physical model was written based on the kinetics of deposition of a compressible fiber mat and a drainage model for the filtrate. After some mathematical arrangements, a model similar to Hermans and Bredée’s formulation was obtained. It states that, at a constant suction pressure, the amount of filtrate per unit surface area is proportional to the square root of suction time. Our approach also yields an equation that is similar to the empirical drainage model used in the paper industry, which links the drained flow rate to a power law of the suction pressure and of the dwell time. By identification of the values of the coefficients, it is then possible to analyze the compressibility of the fibrous mat. For purpose of validation, experimental investigations were performed on one slotted suction box of a Fourdrinier pilot paper machine. The suction pressure was varied from 0.5 to 3.0kPa and the dwell time was changed by successively increasing the number of slots from 1 to 6 slots. The flow rate of filtrate was measured in each case in order to determine the corresponding specific amount of filtrate. Result analysis confirmed that the specific volume of filtrate varies as the square root of the dwell time. In addition, we could calculate the basis weight of the mat deposited on the wire upstream of the suction box and on the suction box itself, the average specific filtration resistance which was 1010 mkg−1 for the studied case. The methodology developed in this study can be transposed to other dead-end filtration processes. [Copyright &y& Elsevier]

This paper describes research involving an in-service failure of a "variable pitch in motion" fan's blade bearing. Variable pitch in motion fans rotate at a constant speed, with the changing blade angle varying the load. A pitch-change mechanism facilitates the change in blade angle. A blade bearing supports each blade enabling it to rotate. The author observed that as the fan aerodynamic stage loading progressively increased, so did the rate of blade-bearing wear. The reported research addressed two separate, but linked, needs. First, the ongoing need to increase fan pressure development capability required an increase in fan loading. This increase was within the context of an erosive operating regime which systematically reduced fan pressure development capability. The second need was to identify the root cause of blade-bearing failures. The author addressed the linked needs using a computational analysis, improving the rotor inflow aerodynamic characteristics through an analysis of the inlet box and design of inlet guide vanes to control flow nonuniformities at the fan inlet. The results of the improvement facilitated both an increase in fan-pressure-developing capability and identification of the root cause of the blade-bearing failures. [ABSTRACT FROM AUTHOR]

Abstract: The characteristics of the flow over the rudder’s pintle gap are investigated by using the particle image velocimetry (PIV) technique. The propeller and rudder models are scaled down to 1/28.5. Highly accelerated leakage outflows are separated at the discontinuities of the gap and generate strong cavitation at the suction side of the rudder. In the rudder and propeller configuration, the propeller wake sheet ahead of the gap entrance region starts to induce leakage flow over the lower pintle gaps of the suction side. The gap flow has a velocity magnitude as high as 0.4U 0 in the high leakage flow condition, where the wake sheet locates over the gap entrance. The cross-flow of the propeller wake sheet interferes the gap entrance region and triggers gap cavitation. As the propeller wake sheet moves downstream and weakens, the gap flow velocity decreases over the gap entrance. [ABSTRACT FROM AUTHOR]

A total of 150 different organisms, including one plant species and 12 animal phyla were identified from sea-chests of 42 vessels visiting or operating in New Zealand between May 2000 and November 2004. Forty-nine percent of organisms were sessile, 42% mobile adults and the remaining 9% sedentary. Decapods were the most represented group with 19 species present among 79% of vessels. Forty percent of organisms were indigenous to New Zealand, 15% introduced, 10% non-indigenous, and 35% of unknown origin. Sea-chests have the potential to (1) transfer non-indigenous organisms between countries across oceanic boundaries; and (2) disperse both indigenous and introduced organisms domestically. The occurrence of adult mobile organisms is particularly significant and indicates that sea-chests may be of greater importance than ballast water or hull fouling for dispersing certain marine species. These findings emphasise the need to assess and manage biosecurity risks for entire vessels rather than different mechanisms (i.e., ballast water, hull fouling, sea-chests, etc.) in isolation. [Copyright &y& Elsevier]