Periods Of Immersion In Water Research Articles

Nanosecond laser interference ablation of fluorine-free aluminum alloy surfaces for dynamic adhesion and static wettability synergistically modulating water collection

Water collection from mist is a potential solution to water scarcity, which is a critical issue worldwide. In this paper, laser interference ablation assisted with stearic acid immersion has been used to achieve synergistic modulation of dynamic adhesion and static wettability for water collection on fluorine-free aluminum alloy surface. The research demonstrates that there is an optimal balance point between dynamic adhesion and static wettability for water collection. This optimal point shifts toward low dynamic adhesion at the high misting rate due to the flooding on metastable surfaces with high dynamic adhesion. In addition, wetting transition induced by tilting is observed on metastable surfaces. The good stability of the proposed fluorine-free surface has been demonstrated by the long-term water collection and long periods of immersion in water. This work can provide theoretical inspiration and a scalable preparation method for green and stable water collection strategies.

Experimental evaluation of fatigue performance of recycled asphalt mixture using refined separation recycled aggregates

In order to improve the utilization of reclaimed asphalt pavement (RAP) in recycled asphalt mixtures (RAMs), RAP was firstly separated into recycled mortar and coarse refined separation recycled aggregates (CRSRAs) with different particle sizes based on a laboratory refined separation method. Meanwhile, the process parameters for RAP separation were optimized by using the orthogonal test method. The related properties of the aggregates before and after refined separation, including residual bitumen binder content, particle agglomeration, angularity, and sphericity, were characterized. The cumulative distribution of sphericity of CRSRAs was fitted with the Weibull function. Asphalt mixtures with 0, 30%, and 50% RAP content were prepared by the Marshall design method. Moreover, the indirect tensile dynamic modulus and fatigue life of these asphalt mixtures after different water immersion periods were evaluated. The results showed that the CRSRAs had a residual binder content less than 1.0% and fewer pseudo particles after refined separation. Furthermore, a bitumen-rich mortar with a particle size less than 2.36 mm and a bitumen content of 10–14% was obtained. Angularity and Weibull fitting results verified that refined separation could homogenize RAP and obtain CRSRAs with a low variability, which helps to prepare better RAMs with high RAP content. RAMs prepared with CRSRAs exhibit superior fatigue performance compared to the traditional RAMs. Their fatigue life was less sensitive to stress changes and fluctuated little with the increasing water immersion time.

Effect of heat treatment on mechanical behavior and scaling resistance of slag impregnated low strength recycled compacted concrete

Recycling concrete waste via high-pressure compaction is a new way of producing recycled concrete, which is developed in 2016. However, it is limited in that the compressive strength of the compacted product is less than 21 MPa. This study focuses on the characterization of recycled compacted concrete (also referred to as compact) quantified according to mechanical behavior, including compressive strength, flexural strength, tensile strength, and scaling resistance, quantified based on a salt scaling test. Investigations were conducted to enhance the strength of compact from previous studies by observing the influence of byproducts such as granulated blast furnace slag and base course materials of iron and steel slag (as replacements for natural fine and coarse aggregates) using water immersion and heat treatment. At 100% replacement, heat treatment increased the compressive, tensile, and flexural strengths by 1.77, 2.23, and 2.32 times, respectively than that of the untreated specimens. Also, morphological observation through Scanning Electron Microscopy indicated that bond performance of compact is improved by incorporating slag materials. This study experimentally demonstrated the potential of heat treatment in the strength enhancement of compacts after specified water immersion period and thus, rendered heat treatment as a prospective experimental method of increasing the strength of compact.

Improvement of the Impact Strength Properties for Nanocomposites Based on Polymers

This study aims to prepare composite materials and improve some of their mechanical properties by using epoxy resin (EP) and polyurethane (PU) as the matrix material and nanoparticles (Al2O3) as reinforcing agents in different ratio with weight fractions (5%, 10%, and 15%). The results in the tables show that increasing the weight fraction of nanoparticles leads to an increase in the elasticity coefficient and durability of the impact and absorbed energy, with an increase in the temperature of the composite material reinforced with nanoaluminum oxide particles. The mechanical properties gradually decrease with the increase of the period of immersion in water.

Rivers as a potential dispersing agent of the invasive tree Acacia dealbata

BackgroundThe silver wattle Acacia dealbata is a fast-growing tree from Australia that has become naturalised in different regions of the world, attaining invasive status in most of them. In Chile, A. dealbata reaches large abundances along banks and floodplains of invaded fluvial systems, suggesting that rivers may act as a vector for seed dispersal. As hydrochory has not been documented previously in this species, the aim of this study is to evaluate the potential for water dispersal of seeds of this invasive tree along rivers.MethodsSeed samples from rivers were collected at three sites along two A. dealbata-invaded rivers within the Cachapoal basin, central Chile. Number of seeds collected was contrasted versus hydraulic and local conditions with RDA. Seed buoyancy and sedimentation velocity were determined and compared between sites with an ANCOVA. Finally, the probability of seed germination after long periods of immersion in water was assessed, simulating transport conditions in the flow. Germination results were tested with a GLM.ResultsResults indicate that increasing abundance of A. dealbata seeds in the flow is related to the level of turbulence of the flow. Seeds display high floatability but their sedimentation velocity is high when they do sink. Finally, silver wattle seeds can germinate after long periods (many weeks) of immersion in water; however, their probability of germination depends to a large extent on whether seeds are scarified or not.ConclusionsBased on the evidence collected, we suggest that the seeds of A. dealbata have the necessary traits to be dispersed by rivers, this being the first research testing this hypothesis. The success of hydrochory of A. dealbata would depend on river flow turbulence, and whether there are natural mechanisms for scarifying the seeds either before or during transport. The proposed methodology can be used to assess river hydrochory for any tree species.

Physical and Mechanical Properties and Decay Resistance of Poplar Modified with mDMDHEU

Chemical modification as a non-biocidal treatment is an effective method to improve physical and biological properties of wood. Poplar is a fast growing species but has poor dimensional stability and durability in addition to low mechanical properties. Low molecular weight Dimethylol dihydroxyethyleneurea (mDMDHEU) was used to improve the properties of poplar mainly dimensional stability and decay resistance. Results indicated high anti-swelling efficiency (ASE), but low variation between both concentrations of mDMDHEU. Tangential swelling was greatly reduced by mDMDHEU treatment during the water immersion period. Untreated poplar samples were severely decayed as compared to modified samples. Modified samples showed lower bending strength unlike to compression strength. Ester peak at 1720 cm-1 revealed chemical reaction between chemical reagent and wood cell wall components. Control samples exhibited considerably higher thermal degradation when compared to the samples modified with mDMDHEU.

Novel animal feed binder from soybean hulls -evaluation of binding properties

The physical properties, especially water stability, of aquatic animal feed are important components of feed quality. Novel feed binders from soybean hulls (SBH) were developed to further improve water stability of the compound feed. Three (SBH) -based binders were evaluated as binding agent (2%) against three natural control binders (carboxymethyl cellulose (CMC), corn starch (CS) and wheat glucan (WG)) with respect to water stability and nutrient leaching after being immersed in water up to 48 h at two water temperatures (22 °C and 28 °C). Pacific white shrimp, Litopenaeus vannamei (mean weight of 6.08 ± 0.04 g) were fed in triplicate aquaria with the experimental diets at a rate of 4% of body weight per day, four times daily, for 6 weeks in a recirculating water system. Diets with SHB had significantly improved pellet water stability compared to the diets with control binders (CS and WG) after being immersed in water for longer than 12 h. CMC had the poorest water stability at 3 h and longer water immersion. Recovery of pellets with soybean hull binders was significantly higher than the pellets with control binders at 24 h of water immersion. After 48 h of water immersion, only diets with SHB were recovered ranging from 30% to 40%. Increasing water temperature resulted in a corresponding decrease in water stability of all pellets. At higher water temperature, however, water stability of pellets with control binders were significantly lower compared to pellets with SHB. The binder that best retained crude protein in all time periods was SHB-3. However, it was not significantly different from other soybean hull binders. Percent lipid remained unchanged in all leached pellets up to 12 h of water immersion and increased afterward. Percent ash of the leached pellets increased at 3 h of immersion and continued to increase with the increasing period of water immersion. Diets with SHB retained higher nutrients than the diets containing control binders after being immersed in water 3 h or longer. Weight gain and survival of shrimp fed diets with control or SHB for 6 weeks were not significantly influenced by binder type. In summary, the SBH-bound pellets were more water stable than the control binders and can produce better and be less expensive natural alternatives to conventional binders.

Evaluation of the Water Sorption and Solubility Behavior of Different Polymeric Luting Materials.

Objective: The study evaluated the water sorption (WSP) and water solubility (WSL) characteristics of different luting agents over a 180-day water storage period. Materials and Methods: Nine luting materials, i.e., conventional resin cement: Panavia F (PF), Rely X ARC (RA), self-adhesive resin cement: Rely X Unicem (RU), Breez (BZ), Maxcem Elite (MX), BisCem (BC) and resin-modified glass ionomer cement: FujiCem (FC), FujiPlus (FP) Rely X luting plus (RL) were assessed and fifty-two-disc specimens of each material were fabricated. All specimens were desiccated until a constant weight (W0) was reached. Thirteen specimens for each luting material were then randomly assigned to one of the four water immersion periods (7, 30, 90, and 180 days). After each period, the specimens were removed from the water and weighed to get W1. The samples were again desiccated for a second time and W2 was measured. Both WSP and WSL were determined by the following equations: WSP (%) = (W1 − W2) × 100/W0 and WSL (%) = (W0 − W2) × 100/W0. Assessments were performed following ISO standards. ANOVA was used to assess the effect of luting agent and time period on water sorption and solubility. Pair-wise comparisons were adjusted using Tukey’s multiple comparison procedure. A significance level of 0.05 was used for all statistical tests. Results: The highest mean WSP and WSL (WSP/WSL) were demonstrated by resin-modified glass-ionomers (RL 18.32/3.25, FC 17.08/4.83, and FP 14.14/1.99), while resin luting agents showed lower WSP and WSL results (PF 1.6/0.67 and RA 1.76/0.46), respectively. The self-adhesive agents exhibited a wide range of WSP and WSL values (RU 1.86/0.13, BZ 4.66/0.93, and MX 3.68/1.11). Self-adhesive cement showed lower WSP and WSL compared with the resin-modified glass-ionomers (p < 0.05). All the materials reached equilibrium after 90-days. Conclusions: Resin-based luting materials have the lowest sorption and solubility. Rely X Unicem self-adhesive luting materials were comparable to resin luting materials for WSL and WSP. Resin-modified glass-ionomer showed the highest water sorption and solubility compared with both resin and self-adhesive materials.

Tracking astronaut physical activity and cardiorespiratory responses with the Bio‐Monitor sensor shirt

Astronauts develop insulin resistance, and are at risk for cardiovascular deconditioning, during long-duration missions to the International Space Station (ISS) despite their daily exercise sessions (Hughson et al. Am J Physiol Heart Circ Physiol 310: H628–H638, 2016). Chronic unloading of the musculoskeletal and cardiovascular systems in microgravity dramatically reduces the challenge of daily activities, and the astronauts’ schedules limit them to approximately 30-min/day aerobic exercise. To understand the physical demands of spaceflight and how these change from daily life on Earth, the Vascular Aging experiment is equipping astronauts for 48-72h continuous recordings with the Canadian Space Agency's Bio-Monitor wearable sensor shirt. The Bio-Monitor (Bio-M), developed from the commercial Hexoskin® device, consists of 3-lead ECG, thoracic and abdominal respiratory bands, 3-axis accelerometer, skin temperature and SpO2 sensor placed on the forehead. Our utilisation of this equipment necessitated the development of novel processing and visualisation techniques, to better interpret and guide subsequent data analyses. Here we present initial data from astronauts wearing the BioM prior to launch and aboard the ISS, demonstrating the ability to extract useful data from BioM, using software developed ‘in-house’. Astronauts wore the Bio-M continually for 72-h except for periods of water immersion or when the device conflicted with another activity. After physical exercise, astronauts changed to a dry shirt. First, we assessed the key data-quality metrics to provide initial appraisals of acceptable recordings. Mean total recording length pre-flight (60.5 hours) was similar to that in-flight (66.5 hours), with a consistent distribution of recorded day (44% vs 45%, 6am-6pm) and night (56% vs 55%, 6pm-6am) hours (pre-flight vs in-flight respectively). For each recording, quality assessment of ECG signals was performed for individual leads, before combining signals and cross-correlating R-waves to produce reliable heart-rate timings. Mean ECG quality for individual leads, represented here as the percentage of usable signal to total recording duration, was somewhat lower in-flight (92%) when compared to pre-flight (96%), likely caused by poor skin contact or dry shirt electrodes; combining lead signals as mentioned above improved the proportion of usable data to 97% and 98% respectively. Accelerometer recordings identified a significant reduction in high-force movements over the 72-hour recordings, with just over 2.5 hours/day of high-force activity in astronauts pre-flight vs 50 minutes/day in-flight. It should be noted however that accelerometer measurements in zero-gravity are likely to be reduced, and future refinement of activity data continues. Average heart rates in-flight showed little difference when compared to pre-flight, although future analyses will compare periods of sleep, rest, and activity to further refine this comparison. We conclude that utilisation of the BioM hardware with our own analysis techniques produces high-quality data allowing for future interpretation and investigation of spaceflight-induced physiological adaptations.

Early Age Compressive Strength of Waste-based-glass-powder Magnesium Silicate Binders on Initial Carbonation Curing

In this preliminary study, the effect of glass powder content at early age compressive strength and its effect at strength retention coefficient during water immersion period on magnesium silicate hydroxide cement pastes on carbonation curing was investigated. A magnesium oxide-rich powder with a maximum grain size of 150 μm was used, as well as, a waste glass powder with a maximum grain size of 250 μm, which was obtained from grinded flint glass bottles. Cement pastes were produced with 0, 10, 20, 30, 40, and 50 glass powder weight percentage. The specimens were compacted into cubic moulds (e = 20 mm) under 70 MPa and, subsequently, cured on accelerate carbonation chamber for 2h at &gt;99% CO2 concentration. The compressive strength was determined 3 days after CO2, period which the specimens were preserved on room conditions (20∘C and 60%RH), and also at 3, 7 and 14 days of water immersion period. Comparison of the results obtained for different mixing compositions, as well as, different water immersion periods are discussed in this work.

Recycling waste materials in geopolymer concrete

The widespread industry adoption of geopolymer concrete has the potential to positively contribute to environmental sustainability in both the industrial and construction sectors, through the recycling of waste materials, and the reduction in carbon emissions. Extensive research has been conducted into geopolymers during the past two decades, demonstrating the potential for the alkali-activated cement to replace ordinary Portland cement. However, there are a number of challenges facing the adoption of geopolymers. Much of the research into geopolymers uses sodium silicate solution as the alkali activator. Studies have noted that sodium silicate solutions are highly corrosive, and, as such, can be defined as user-hostile systems. Alternative alkali activators, such as potassium silicate solutions, have been proposed as more user-friendly and therefore more favourable for industry adoption. The highly variable nature of waste materials needs to be a focus of future research, with mix designs that focus on locally available waste materials with minimal processing. Much research has focused on heat-cured geopolymers; however, this increases the embodied energy while reducing the environmental benefit, which also acts as a limiting factor for in situ applications. Research into ambient temperature curing, addressing the issues of compressive strength, the rate of strength development, and curing time is required. Durability issues need to be addressed with studies finding the compressive strength of geopolymers being reduced after relatively short time periods of immersion in water, and potential problems relating to chloride induced corrosion of reinforcing steel. Further research is recommended for developing standardized leachate analysis for geopolymers containing recycled waste materials. The objective of this paper is to review the research into waste-incorporated geopolymers and highlight the barriers to industry adoption with a view to pointing the way forward for future research.

Water distribution in wood after short term wetting

Water has a major influence on wood properties, especially dynamic moisture cycles, which affect the wood in outdoor applications. It is thus important to understand the penetration and distribution of water in wood. In this study, rainfall events were simulated to correspond to water immersion periods of 1 h. Specimens were imaged by magnetic resonance imaging (MRI) after 1 h of immersion. These measurements were used to determine the water distribution in the wood and to elucidate changes during the drying of specimens of five wood species: sweet chestnut heartwood (Castanea sativa), European larch heartwood (Larix decidua), Scots pine heartwood and sapwood (Pinus sylvestris) and Norway spruce (Picea abies). Both gravimetric and MRI analysis showed that after 1 h of immersion, pine sapwood took up the highest amount of water, followed by spruce wood. Considerably lower moisture contents were determined in pine heartwood, chestnut and larch, which correlated with a lower signal intensity. The outer parts of the specimens exhibited similar patterns with all of the specimens. The most variable results were the moisture content time profiles in the middle part of the specimens. Comparison of the MRI measurements and gravimetrically determined moisture contents during drying validated the MRI measurements and confirmed the method to be suitable for giving comprehensive information about the water drying kinetic.

Strange lights in the night: using abnormal peaks of light in geolocator data to infer interaction of seabirds with nocturnal fishing vessels

Many seabird species forage at night and potentially interact with nocturnal fishing activities. Jigging fisheries use powerful lights to attract squid, and such high intensity lights can be recorded using global location-sensing loggers (geolocators) attached to seabirds. We use this potential source of information as evidence for interaction of southern giant petrels Macronectes giganteus with night fisheries during the non-breeding season. We compared the number of light spikes at night between sexes and evaluated whether the intensity of the light on those geolocator records matched periods of water immersion (wet–dry) of geolocators, as a measure of foraging activity. Females had more night light spikes than males, and although the activity on water was higher during nights with light spikes than nights without light spikes for both sexes, females had a higher probability to be resting on the water when peaks of light were higher. Females moved further north than males and used areas of higher squid fishery activities within Patagonian waters. This type of information is useful to record potential interactions with night fisheries and proposes that future studies should relate the accurate distribution of individuals (from GPS loggers) with light information (geolocators data) to highlight this undocumented interaction. Southern giant petrels are recognized as interacting intensively with fisheries off Patagonia waters with consequences for population dynamics (e.g. mortality through bycatch events).

Effect of Post-thermal shock on Prolonged Sea Water aged GFRP Composite

The present investigation is an attempt of evaluating the suitability of glass fibre reinforced polymer composites to thermal shock treatments of various lengths of time subject to pre-immersion in sea water for 1 year. Mechanical properties like inter laminar shear strength (ILSS), stress at rupture, strain at rupture and modulus values are recorded by adopting 3-point bend test method. Mechanical properties show a general decreasing trend at higher durations of up and down-thermal shock exposure irrespective of showing initial nonequilibrium zig-zag trend. Glass Transition temperature (Tg) with respect to optimum durations of thermal shock treatment show considerable variation for the sample with minimum sea water immersion period. SEM fractographs of the thermally shocked specimens revealed the mode of failures like fibre pull out, fibre/matrix debonding, cusp formation indicating polymer crazing, matrix cracking, fibre breaking etc.

Jute/polypropylene composites: Effect of enzymatic modification on thermo-mechanical and dynamic mechanical properties

In this study, a high-performance composite was prepared from jute fabrics and polypropylene (PP). In order to improve the compatibility of the polar fibers and the non-polar matrix, alkyl gallates with different hydrophobic groups were enzymatically grafted onto jute fabric by laccase to increase the surface hydrophobicity of the fiber. The grafting products were characterized by FTIR. The results of contact angle and wetting time showed that the hydrophobicity of the jute fabrics was improved after the surface modification. The effect of the enzymatic graft modification on the properties of the jute/PP composites was evaluated. Results showed that after the modification, tensile and dynamic mechanical properties of composites improved, and water absorption and thickness swelling clearly decreased. However, tensile properties drastically decreased after a long period of water immersion. The thermal behavior of the composites was evaluated by TGA/DTG. The fiber-matrix morphology in the modified jute/PP composites was confirmed by SEM analysis of the tensile fractured specimens.

PH do Exsudato na Avaliação da Viabilidade de Sementes de Araucaria angustifolia

RESUMOEste estudo objetivou verificar a eficiência de métodos de pré-condicionamento e períodos de embebição em água para a realização do teste de pH do exsudato para avaliação da viabilidade de sementes de Araucaria angustifolia. Testaram-se três pré-condicionamentos (semente inteira; semente seccionada longitudinalmente; embrião excisado) e três períodos de embebição em água (30, 60 e 90 minutos), avaliando-se a coloração da solução. Adicionalmente, as sementes foram envelhecidas artificialmente por 4 e 8 dias, a 40 °C. A viabilidade foi superior em embriões excisados e embebidos por 30 minutos, apresentando elevado coeficiente de correlação com os testes de germinação e tetrazólio. Para sementes em avançado estádio de deterioração, a avaliação deve associar a coloração da solução ao aspecto dos tecidos. Conclui-se que o teste do pH do exsudato é eficiente na avaliação da viabilidade de sementes de A. angustifolia, devendo ser realizado utilizando-se apenas o embrião embebido em água por 30 minutos.

The Effect of Light Exposure on Water Sorption and Solubility of Self-Adhesive Resin Cements.

Purpose. To investigate the effect of light activation on the water sorption (WS) and solubility (SL) of resin cements after 24 h and 7 days. Methods. Disk-shaped specimens were prepared using five dual-polymerized cements (four self-adhesive [RelyX Unicem, MaxCem, SeT and G-Cem] and one conventional [Panavia F 2.0]) and divided according to the curing mode (direct light exposure or self-cure) and water immersion period (24 h or 7 days). Specimens were dry-stored and weighed daily until a constant mass was recorded (M1). Then, specimens were stored in water for either 24 h or 7 days and immediately weighed (M2). After desiccation, specimens were weighed again until a constant mass was achieved (M3). WS and SL were calculated and statistically analyzed by Kruskal-Wallis, Dunn and Mann-Whitney U tests (α = 0.05%). Results. There was a significant increase in WS for all products after one-week immersion in water. The highest water uptake was observed for autopolymerized groups. Extended water immersion significantly affected the SL for most of autopolymerized cements. Significant differences between products were observed in both tests. Conclusions. The curing mode and the water immersion period may affect the mechanical stability of the resin cements, and these differences appear to be product-dependent.

Stability of the bond between two resin cements and an yttria-stabilized zirconia ceramic after six months of aging in water

The behavior of the luting cement and the cementation protocol are essential in the clinical success of ceramic restorations. The purpose of this study was to evaluate the bond stability of 2 resin cements and a yttria-stabilized tetragonal polycrystalline zirconia (Y-TZP) ceramic submitted to 2 surface treatments. Sixty plates of a Y-TZP ceramic were assigned to 3 groups according to the surface treatments: control, as sintered surface; methacryloxydecyl dihydrogen phosphate (MDP), coated with an MDP-based primer, and tribochemical silica-coating (TSC), coated with tribochemical silica. The plates of each group were further divided into 2 subgroups according to the resin cement as follows: RelyX adhesive resin cement (conventional) and RelyX Unicem (self-adhesive). Cylinders of resin cements (∅=0.75 mm× 0.5 mm in height) were built upon the ceramic surfaces, and the plates stored in distilled water at 37°C for either 24 hours or 6 months before being submitted to a microshear bond strength test. The data were submitted to 3-way ANOVA and the Tukey honestly significant difference test (α=.05). Three-way ANOVA showed statistical significance for the 3 independent factors: resin cement, surface treatment, andperiod of water immersion (P<.001). Unicem presented the highest microshear bond strength after 24 hours (MDP, 37.4±2.3and TSC, 36.2 ±2.1 MPa). Except for RelyX adhesive resin cement applied on ceramic surfaces treated with TSC, the microshear bond strength of all the other groups decreased after 6 months of aging in water. The microshear bond strength decreased most in the control groups (-81.5% for ARC and-93.1% for Unicem). In the group treated with TSC, the microshear bond strength for Unicem decreased by 54.8% and in that treated with MDP-based primer by-42.5%. Inthe group treated with MDP-based primer, the microshear bond strength for RelyX ARC decreased by-52.8%. Irrespective of surface treatments, self-adhesive resin cement was not able to maintain the bond to Y-TZP ceramic after 6 months of aging in water.

Temperature affects immersion tolerance of first-instar nymphs of the Australian plague locust, Chortoicetes terminifera

The population dynamics of the Australian plague locust, Chortoicetes terminifera, are strongly linked to the timing and distribution of heavy rainfall events in semiarid and arid environments. While the effects of insufficient rainfall on survival are relatively well understood, little information exists on the effects of excessively wet conditions. This study aimed to quantify the survival of first-instar C. terminifera nymphs to a range of water-immersion periods and temperatures. Results show that survival is strongly dependent on immersion temperature whereby survival times ranged from time to 50% mortality (LT50) = 8.12 ± 0.26 h at 15°C to 4.93 ± 0.30 h at 25°C. Nymphs entered a coma-like state within 2 min of immersion. Post-immersion recovery times were greater for longer immersion periods and longer at higher temperatures for immersion periods of &gt;3 h. These findings suggest that first-instar nymphs would be able to survive most instances of transient, localised pooling of water associated with heavy rainfall in the field. However, flooding that could trap individuals for &gt;5 h (including nymphs still underground within the egg pod before emergence to the soil surface) has the potential to cause high mortality, particularly during summer and early autumn when water temperatures may be high.

Impact of Infrastructure Coating Materials on Storm-Water Quality: Review and Experimental Study

A literature review and 30-day leaching regime were conducted to determine the extent storm-water infrastructure coatings affect water quality. Newly installed polymer-enhanced cement mortar (PECM) and polyurea (PEUU) storm-water pipe coatings were removed from the field and underwent 10 three-day water immersion periods. For both materials, the greatest water quality alterations occurred during the first water contact period, followed by significant reductions in water quality alterations. Mineral release from PECM consistently elevated pH from 7.1 to 10.1–11.8 throughout the entire study. Organic contaminant release [total organic carbon (TOC) and UV254] was also detected for PECM during the first two water contact periods only. Alkalinity increased by 534 mg/L as CaCO3 because of the first contact period and 18–50 mg/L as CaCO3 for each remaining periods. Isocyanate resin from PEUU reacted with water and reduced water pH by 1.0 to 1.2 pH units during the early contact periods and lesser magnitude for the remaining exposure period. Chemical oxygen demand (COD), TOC, and UV254 results showed that organic contaminants were released from PEUU. A limited quantity of organic contaminants released by PEUU was biodegradable. Nitrogen compounds were detected only during the first PEUU water contact period.