Ow Conditions Research Articles

Effects of ocean acidification over successive generations decrease resilience of larval European sea bass to ocean acidification and warming but juveniles could benefit from higher temperatures in the NE Atlantic.

European sea bass (Dicentrarchus labrax) is a large, economically important fish species with a long generation time whose long-term resilience to ocean acidification (OA) and warming (OW) is not clear. We incubated sea bass from Brittany (France) for two generations (>5 years in total) under ambient and predicted OA conditions (PCO2: 650 and 1700 µatm) crossed with ambient and predicted OW conditions in F1 (temperature: 15-18°C and 20-23°C) to investigate the effects of climate change on larval and juvenile growth and metabolic rate. We found that in F1, OA as a single stressor at ambient temperature did not affect larval or juvenile growth and OW increased developmental time and growth rate, but OAW decreased larval size at metamorphosis. Larval routine and juvenile standard metabolic rate were significantly lower in cold compared with warm conditioned fish and also lower in F0 compared with F1 fish. We did not find any effect of OA as a single stressor on metabolic rate. Juvenile PO2,crit was not affected by OA or OAW in both generations. We discuss the potential underlying mechanisms resulting in the resilience of F0 and F1 larvae and juveniles to OA and in the beneficial effects of OW on F1 larval growth and metabolic rate, but contrastingly in the vulnerability of F1, but not F0 larvae to OAW. With regard to the ecological perspective, we conclude that recruitment of larvae and early juveniles to nursery areas might decrease under OAW conditions but individuals reaching juvenile phase might benefit from increased performance at higher temperatures.

A Preliminary Investigation of the Effects of Obstacle Negotiation and Turning on Gait Variability in Adults with Multiple Sclerosis.

Many falls in persons with multiple sclerosis (PwMS) occur during daily activities such as negotiating obstacles or changing direction. While increased gait variability is a robust biomarker of fall risk in PwMS, gait variability in more ecologically related tasks is unclear. Here, the effects of turning and negotiating an obstacle on gait variability in PwMS were investigated. PwMS and matched healthy controls were instrumented with inertial measurement units on the feet, lumbar, and torso. Subjects completed a walk and turn (WT) with and without an obstacle crossing (OW). Each task was partitioned into pre-turn, post-turn, pre-obstacle, and post-obstacle phases for analysis. Spatial and temporal gait measures and measures of trunk rotation were captured for each phase of each task. In the WT condition, PwMS demonstrated significantly more variability in lumbar and trunk yaw range of motion and rate, lateral foot deviation, cadence, and step time after turning than before. In the OW condition, PwMS demonstrated significantly more variability in both spatial and temporal gait parameters in obstacle approach after turning compared to before turning. No significant differences in gait variability were observed after negotiating an obstacle, regardless of turning or not. Results suggest that the context of gait variability measurement is important. The increased number of variables impacted from turning and the influence of turning on obstacle negotiation suggest that varying tasks must be considered together rather than in isolation to obtain an informed understanding of gait variability that more closely resembles everyday walking.

Ocean warming and acidification may challenge the riverward migration of glass eels.

The dramatic decline of European eel ( Anguilla anguilla) populations over recent decades has attracted considerable attention and concern. Furthermore, little is known about the sensitivity of the early stages of eels to projected future environmental change. Here, we investigated, for the first time, the potential combined effects of ocean warming (OW; Δ + 4°C; 18°C) and acidification (OA; Δ - 0.4 pH units) on the survival and migratory behaviour of A. anguilla glass eels, namely their preference towards riverine cues (freshwater and geosmin). Recently arrived individuals were exposed to isolated and combined OW and OA conditions for 100 days, adjusting for the salinity gradients associated with upstream migration. A two-choice test was used to investigate migratory activity and shifts in preference towards freshwater environments. While OW decreased survival and increased migratory activity, OA appears to hinder migratory response, reducing the preference for riverine cues. Our results suggest that future conditions could potentially favour an early settlement of glass eels, reducing the proportion of fully migratory individuals. Further research into the effects of climate change on eel migration and habitat selection is needed to implement efficient conservation plans for this critically endangered species.

Moisture and temperature in a proppant-enveloped silt block of a recharge dam reservoir: Laboratory experiment and 1-D mathematical modelling

Mosaic 3-D cascade of parallelepiped-shaped silt blocks, which sandwich sand- lled cracks, has been discovered in the eld and tested in lab experiments. Controlled wetting-drying of these blocks, collected from a dam reservoir, mimics field ponding-desiccation conditions of the topsoil layer subject to caustic solar radiation, high temperature and wind, typical in the Batinah region of Oman. In 1-D analytical modelling of a transient Richards’ equation for vertical evaporation, the method of small perturbations is applied, assuming that the relative permeability is Avery-anov’s 3.5-power function of the moisture content and capillary pressure is a given (measured) function. A linearized advective dispersion equation is solved with respect to the second term in the series expansion of the moisture content as a function of spatial coordinates and time. For a single block of a nite thickness we solve a boundary value problem with a no- ow condition at the bottom and a constant moisture content at the surface. Preliminary comparisons with theta-, TDR- probes measuring the moisture content and temperature at several in-block points are made. Results corroborate that a 3-D heterogeneity of soil physical properties, in particular, horizontal and vertical capillary barriers emerging on the interfaces between silt and sand generate eco-niches with stored soil water compartments favourable for lush vegetation in desert conditions. Desiccation significantly increases the temperature in the blocks and re-wetting of the blocks reduces the daily average and peak temperatures, the latter by almost 15°C. This is important for planning irrigation in smartly designed soil substrates and sustainability of wild plants in the region where the top soil peak temperature in the study area exceeds 70°C in Summer but smartly structured soils maintain lash vegetation. Thee layer of dry top-blocks acts as a thermal insulator for the subjacent layers of wet blocks that may host the root zone of woody species.

Evaluating the effects of high liquid viscosity and flow variables on horizontal oil–gas slug flows by gamma radiation method

Hydrodynamic slug fl ow is the commonest fl ow regime observed in high viscosity liquid–gas horizontal pipelines over a wide range of different fl ow conditions. Hydrodynamic slugging tends to generate large vibrations that may impose structural instability or even damage oil production pipelines. For that reason, there is a need to investigate high viscosity slug fl ow regime to understand its complex characteristics. This is pertinent when considering that existing slug fl ow models used in the petroleum industry to design production pipelines are not suitable for predicting the behaviour of high viscosity oil–gas fl ow. In this study, the effects of liquid viscosity and fl ow variables on slug fl ow regime were investigated experimentally through the analysis of two key parameters—slug frequency and slug body liquid holdup, both measured with a gamma densitometer. Comparison of the measured slug parameters to existing correlations revealed that slug body liquid holdup correlations were in close agreement with high viscosity experimental data. However, none of the existing slug frequency correlations used was able to produce accurate predictions. A new empirical correlation for slug frequency was proposed. Compared with existing correlations, the newly proposed correlation performed much better in predicting slug frequency of high viscosity liquid–gas fl ows.

The local ventilation system coupled with the indirect green façade: a priliminary study

Green facades are becoming an important architectural element in an urban environment. Regarding the technology of the installation of green facades, one can distinguish between direct and indirect green facades, living walls and double skin facades with foliage. In addition to aesthetics of green facades, an impact on the outdoor and the indoor comfort has been proven. That is due to changed temperature and air fl ow conditions at the building envelope boundary. It has been proven that green facades impact lower surface temperatures of a building envelope and enhance thermal insulation properties of a building envelope, thus reducing the energy demand of a building. Based on the results from green facade thermal response research and growing interest in local ventilation systems, one can conclude that there is potential for a free cooling of a building. Therefore, this paper presents the design and the preliminary experimental research of a local ventilation system coupled with an indirect green facade. Based on the experimental work, it has been ascertained that the indirect green facade can impact a 5 K lower inlet air temperature for the local ventilation system compared with the one at the traditional facade.

Sustainable urban drainage approach, focusing on lid techniques, applied to the design of new housing subdivisions in the context of a growing city

City growth must be carefully planned, in order to deal with the relevant hydrological changes, caused by urbanisation effects. Frequently, the increasing of the impervious surface areas is the major cause of urban fl oods aggravation. For this reason, new urban drainage design concepts have been researched in the recent decades, looking for a more sustainable stormwater management approach. The concept of sustainability in urban drainage implies that fl oods may not be transferred to downstream and that drainage systems must be planned considering urban development along time. Storage and infi ltration measures, distributed over the watershed and integrated with urban landscape, should be introduced to reduce fl ood peaks and reorganise fl ood fl ow patterns. Following this path, the concept of low impact development (LID) may be a reference for urban drainage projects of new housing subdivisions. This concept tends to produce built environments with minor hydrological changes, trying to preserve or recover natural fl ow conditions prior to the urbanisation. In this context, this paper aims to discuss the problems related to urban fl ood in a conceptual, but practical, perspective, comparing different alternatives of drainage design for urban areas in a development process. In particular, a case study in the neighbourhood of Guaratiba, at Rio de Janeiro City, Brazil, will be developed. This region is under an increasing urban growth pressure, but it is still possible to plan and design an alternative occupation. Basically, two approaches were compared: a traditional end of pipe design concept and an alternative sustainable design approach, based on the LID concept. The effects of the LID fl ood control measures were analysed and compared, applied in both public and private areas of a new urban subdivision project. A critical storm event was considered for the local scale and for Cabucu River, which is the receiving water body for the local drainage system. The combined use of infi ltration and storage measures was able to recover fl ood peaks. The pre-urbanisation values were approximately reproduced, both for the local and the basin scales, although peak times were not recovered.

Modeling of Filtration Investigations Under Unstable Conditions of Injection of Water Into Hyperlow-Permeability Samples

We report the results of modeling laboratory experiments for unstable fi ltration conditions. It has been shown that the form of pressure curves is infl uenced by the spurious volume coeffi cient, the length of the core sample, and the collectorpermeability. We have diagnosed by the log-log curves of the pressure and its logarithmic derivative the liquid fl ow conditions for early and later times of the nonstationary fi ltration experiment infl uencing the possibility of estimating the collector permeability. conditions already at distances of about 30 m from the well into the depth of the productive oil fi eld. In (2), the results are presented of the numerical simulation and estimation of the infl uence of a decrease in the effective permeability of the collector at nonlinear fi ltration in low-permeability fl ooded oil fi elds on the remnant oil stock distribution and the oil extraction factor. In the present paper, we have explored the possibility of determining the effective permeability as part of fi ltration investigations under unstable fi ltration conditions. The theory and approaches for working with data on the pressure change were developed and described well by many authors within the framework ofhydrodynamical investigations of wells (HDIW) under unstable fi ltration conditions (3-6). In the present work, these approaches for HDIW were also used to describe laboratory experiments performed under unstable fi ltration conditions. Important points in laboratory fi ltration works are designing of experiments, prevention of possible problems in interpreting obtained data, the infl uence of model parameters on the duration of the investigation and the necessary accuracy of the measuring equipment, and diagnostics of liquid fl ow conditions and boundary effects at early and later times by analyzing the pressure curves and the Bourdet logarithmic derivative (7). In the present paper, we propose a mathematical model that can be used for planning laboratory investigations of core samples under unstable fi ltration conditions and interpreting results. The model takes into account the infl uence of the spurious volume and the change in the collector properties in the skin zone and in the boundary effects of the core sample. 1. Infl uence of the Spurious Volume on the Flow Rate of the Injected Liquid. Thespurious volume is largely determined by the internal volume of metal pipes in the facility for liquid injection located before the inlet to the investigated sample model. In the initial period of the injection/termination processes, due to the infl uence of compression/expansion

Models for the onset of plasma leakage in dengue haemorrhagic fever

Dengue Hemorrhagic Fever (DHF) is a disease caused by Dengue virus infection. The main characteristic of the DHF is plasma leakage that leading to death. By modifying of the Navier Stokes equation, a mathematical model for blood ow conditions at the onset of plasma leakage are built. In this paper, three models of blood condition are reviewed by considering pressure variation i.e. blood ow with a con

Complement- and platelet-mediated shuttling of blood-borne bacteria to CD8A+ dendritic cells

Beyond its role in innate immunity, complement mediates a ide range of functions in tissue remodeling. Although activaion of platelets is crucial during tissue injury and remodeling n multiple diseases, the exact mechanisms how platelet funcions are modulated by complement components remain elusive. e found that platelets express the complement receptor C3aR. timulation of isolated platelets with C3a peptide enhanced ADP nduced aggregation of platelets using aggregometry and resulted n increased adhesion of platelets to fibrinogen under arterial ow conditions. Moreover, platelets isolated from C3aR−/− mice evealed reduced spreading on fibrinogen. In vivo using C3a recepor knockout mice and C5a receptor knockout mice we could emonstrate that specifically lack of the C3a receptor resulted in educed thrombus formation after vascular injury in an intravial microscopy setting. Accordingly, C3aR-deficient mice displayed ncreased bleeding time in tail bleeding time experiments, which ould not be explained by a difference in peripheral platelet count, nd after reperfusion of C3aR+/+ platelets into C3aR−/− mice proongedbleeding timeassociatedwithC3aRdeficiencywas reversed. n an experimental stroke model, C3aR−/− mice displayed reduced nfarct volume, a difference that was abolished in the absence of latelets. In conclusion, these data indicate a new and surprising unctionof theanaphylatoxin receptorC3aRonplatelets forplatelet unction and thrombosis.

OXYGEN MICROENVIRONMENT OF CORALLINE ALGAL TUFTS AND THEIR ASSOCIATED EPIPHYTIC ANIMALS

Separate subhabitats are distinguishable in tufts of Corallina offi cinalis, including the surface of the algae itself and the interspace (areas of water) within the algal tufts. The oxygen microenvironment of each of these was investigated in laboratory investigations using oxygen microelectrodes to test the hypothesis that oxygen gradients form adjacent to the seaweed surface and that the oxygen concentration of the seawater between the branches of individual plants differs from that of the surrounding water body due the tuft forming nature of this seaweed. Regions of hyperoxia (up to 250% of saturation) were detected at the surface of Corallina branches in static conditions, with steep declining gradients of oxygen concentration through the diffusive boundary layer in the vertical plane to 100% of saturation a distance almost 2mm from the surface. Oxygen concentration at the surface did not vary with position along individual branches, or with position on any one branch segment. Concentrations were signifi cantly higher on main branches than on peripheral branches of individual plants. Water fl ow was the dominant factor controlling the depth and oxygen supply of diffusive boundary layers and in moving water oxygen levels did not achieve such high saturation levels and the boundary layer was thinner. On a larger scale, oxygen concentrations in the interspace of C. offi cinalis tufts were highly variable and commonly in excess of air saturation. The oxygen environment was both temporally and spatially dynamic, and very rapid changes in oxygen concentration were observed in response to changing fl ow conditions. Despite the ranges of oxygen concentrations, and often hyperoxic conditions described, a thriving epiphytic community of animals smaller than 2mm, dominated by harpacticoid copepods and marine mites is associated with this extreme and dynamic environment.

Ground water fed system restoration on the area of Przemkowsko-Przecławskie Wetlands

Ground water fed system restoration on the area of Przemkowsko-Przeclawskie Wetlands. The aim of the paper is the estimation of hydrological conditions occurring on the area of Przemkowsko-Przeclawskie Wetlands in the proposed water management scenarios, which are implemented to restore natural values of the wetland environment. In each of the scenarios, the operation parameters of hydraulic structures were changed, causing the potential increase of ground water alimentation to the wetland area. Common and recognized ground water fl ow model MODFLOW was used to calculate ground water levels for each scenario and to study the long-term effect of restoration measures on Przemkowsko-Przeclawskie Wetlands. Following hydrological characteristics were analysed: mean of the mean ground water levels, inundation frequency, mean ground water amplitude and mean low ground water levels. These characteristics were modeled for the long-term period 1964–1985 for unsteady fl ow conditions and were compared with the values adopted from intact, reference wetlands. It was proved, that slowing down the outfl ow of ground water (scenario 1) didn’t provide hydrological conditions desired for the maintenance of swampy habitats. The combination of outfl ow slow down and restriction of ground water abstraction by existing pumping stations (scenario 2) didn’t guarantee the maintenance of desired values of hydrological characteristics for a swampy habitat as well. The realization of the proposed scenarios enables to keep proper conditions for wet and moist habitats. The management policy for Przemkowsko-Przeclawskie Wetlands should then be directed at the development of those habitats, providing broad realization of environmental protection goals.

Basaltic scoria textures from a zoned conduit as precursors to violent Strombolian activity

Pyroclast textures document volcanic conduit processes and may be key to hazard forecasting. Here we show that the relative abundances of mingled, variably crystallized domains in pyroclasts from scoria cone eruptions provide a record of magma ascent velocity and can be used to predict the onset of violent Strombolian activity. Scoria clasts from the Croscat complex scoria cone (Spain) ubiquitously show micrometer- to centimeter-sized, microlite-rich domains (MRD) intermingled with volumetrically dominant, microlite-poor domains (MPD). Glass and bulk composition show that MRDs formed by microlite crystallization of MPDs, the former residing longer in a relatively cooler, degassed zone lining the conduit walls, the latter traveling faster in the central, hotter streamline. MPD and MRD magmas intermingled along the interface between the two velocity zones. The proportion of MPD and MRD in different tephra layers refl ects the extent of the fast- and slow-fl owing zones, thus refl ecting the ascent velocity profi le of magma during the different phases. At Croscat, the MPD/MRD volume ratio increased rapidly during the early Strombolian activity, peaked around the Strombolian to violent Strombolian transition, and then decreased smoothly irrespective of shifts in eruptive style. We suggest that magma ascent velocity escalated during the Strombolian phase due to the buoyant push of the underlying, volatile-rich magma that was about to drive the following violent Strombolian activity. Monitoring the MPD/MRD ratio of tephra during ongoing scoria cone eruptions may reveal changes in magma fl ow conditions and could forecast the onset of hazardous violent Strombolian activity.

Effect of an open window and conspecifics within view on the welfare of stabled horses, estimated on the basis of positive and negative behavioural indicators

AbstractThe effect of environmental enrichment on the welfare of stabled horses was estimated on the basis of positive and negative behavioural indicators. Six stabled horses were exposed for seven days to each of two conditions in early spring: i) a window at the back of the loose box was opened, but no horses were within the view of the subject horses (OW) and ii) the window in the loose box was opened and two horses that had been in the same stable as the subject horses were turned out to the paddock next to the stable and were within view of the subject horses (OWH). The window in the loose box had been closed prior to the start of the study for protection against the cold during winter months (CW condition) but horses could see outside the loose box through the grille door. The behaviour of the subject horses was recorded by video camera from 1300 to 1530h, firstly, in the CW condition for the three days prior to treatment as the control condition, and then for the last three days of each week in the OW and OWH conditions. The behaviour was focal- and instantaneous-sampled at 30-s intervals. Significant differences between the effects of the loose box conditions on the mean percentage of time spent in standing behaviour, looking behaviour, and bedding investigation behaviour (which may be an indicator of frustration) were observed but no significant difference in the mean percentage of time spent in standing-sleep behaviour (which may be an indicator of behavioural satisfaction) was observed. When the window was opened, bedding investigation and standing behaviour decreased and, when the conspecifics were within view, bedding investigation behaviour decreased and looking behaviour increased. The results suggested that the OW and OWH treatments suppressed the frustration of stabled horses which did not perform any abnormal behaviour, but may not increase the behavioural satisfaction of stabled horses.

A Study on the Performance of ARC Pavement for Traffic Noise Reduction - A SPB Comparison with Conventional Pavement

This research investigates traffic noise reduction on highways paved with ARC material and establishes a quantitative model for evaluating the effect of traffic flow on traffic noise. A series of traffic noise measurements have been combined with traffic flow monitoring to compare the sound performance of ARC with conventional pavements and analyze the relationship between the noise levels over ARC pavement with traffic flow conditions. The 24-hour averaged Statistical Pass-By (SPB) noise levels indicate that the ARC pavement demonstrates better sound performance than that of conventional pavement in traffic noise reduction. The energetic averaging method is employed to study the relationship between traffic noise levels and traffic flow conditions. The applicability of ARC pavement to traffic noise reduction under various traffic fl ow conditions is also investigated. A relationship between traffic flow and traffic noise is established in terms of SPB noise levels and the traffic volumes for different vehicle categories. The relationship is employed to compare the noise reduction performance between ARC and conventional pavements under various traffic flow conditions. The research results indicate that ARC pavement is very effective at reducing the noise generated by large vehicles.

Coexistence of an invasive and a native gammarid across an experimental flow gradient: flow-refuge use, -mortality, and leaf-litter decay

The Ponto-Caspian gammarid Dikerogammarus villosus currently expands its range and replaces native gammarid populations in many large rivers of Europe. Results of small-scale, still-water experimentation fostered the idea that D. villosus reduces native gammarid populations in large rivers through predation. However, in large rivers, the prevailing fl ow conditions (potentially harsh or benign for predator and/or prey) and related fl ow-refuge use (potentially concentrating predator and prey in small spaces) could interfere in this predator-prey interaction. We combined a fi eld survey with a mesocosm-fl ume experiment to assess fl ow-refuge use, mortality, and associated effects on leaf-litter decay through potential shredding by the gammarids of coexisting D. villosus and native Gam- marus pulex across a shear stress (τ) gradient. In real running waters, both species had no well defi ned preference for a narrow τ range, suggesting that D. villosus would effectively prey on G. pulex across a wide τ range. In our experiment, however, the concentration of D. villosus and G. pulex in fl ow refuges increased with τ and decreased with the duration of the experiment (decrease of D. villosus < G. pulex). Overall mortality over the entire experi- ment was higher in G. pulex than in D. villosus and tended to decrease with τ in D. villosus, whereas it tended to increase with τ in G. pulex. Decay of alder leaf litter decreased with τ and time; however, the difference (low vs. high τ) of the temporal decay-rate drop was low. Our experimental results support the idea that at higher τ, both D. villosus and G. pulex are concentrated in flrefuges, which facilitates predation of the former on the latter. These fl ow effects on the interaction between D. villosus and a native gammarid (and potentially other rheophilic inver- tebrates) have particularly important implications for restoration projects that increase the discharge in by-passed sections of large regulated rivers, as the concurrent or future invasion of D. villosus could imperil the restoration of rheophilic invertebrate populations.

A Simplified Correlation for Bubble Volume Estimation

as injection into liquids is a common operation employed in many chemical and process engineering applications, such as bubble formation at spargers and single orifi ces in many different gas-liquid contactors. It is well known that both the bubble size and gas held up in a bubble column are important factors, which infl uence the gas-liquid mass transfer, liquid mixing, and residence time of gas and liquid. It is thus essential to estimate the volume of bubbles formed at an orifi ce and to determine factors that can infl uence the bubble size. Many theories on bubble formation have been proposed with experi-mental verifi cations, most of these experiment set-ups consisted of a test chamber with an orifi ce on the bottom plate and a gas chamber attach beneath the orifi ce. Gas is forced to form bubbles at the orifi ce via the gas chamber. It is well known that the gas chamber has a signifi cant effect on bubble formation. The operat-ing conditions can be divided into three regions, namely constant fl ow, intermediate and constant pressure conditions, based on a dimensionless parameter,

Blue InGaN/GaN Light-Emitting Diodes Using Mg-Doped AlGaN Electron-Blocking Barriers

Blue InGaN/GaN multiple-quantum-well light-emitting diodes were grown on sapphire substrates by using a metal-organic vapor phase epitaxy system. A Mg-doped AlGaN electron-blocking barrier was introduced under various Cp2Mg ow conditions at a high temperature of 1050 C. The characterization included current-voltage, capacitance-voltage and electroluminescence analyses. The luminescence e ciency showed an improvement of more than 90 % when the Cp2Mg ow rate was increased from 50 to 200 sccm. The forward voltage was reduced to 3.18 V at 20 mA. The series resistance was also estimated to be 10.81 . Secondary-ion mass spectrometry revealed the Mg doping pro les close to the quantum-well active region. The increased Mg concentration resulted in improved hole injection and carrier concentration. This is in agreement with the increased electroluminescence e ciency and luminous intensity and with the lower turn-on voltage. The Xray di raction study showed a full width at half maximum of 290.1 arcsec from the GaN (0002) di raction and 325.9 arcsec from the GaN (10 12) di raction.

Development of a road traffic noise prediction model under uninterrupted traffic flow conditions

The main objective of this study is to develop a noise prediction model under uninterrupted traffi c fl ow conditions. In this study, Bangalore city in Karnataka, India, was selected as the study area. The study locations are so chosen as to represent the different zones within an urban area like residential zone, commercial zone, silent zone and heavy traffi c zone. Traffi c noise was measured using the Leq index with an A-weighted scale of decibel unit for a 1-hour period at each study location. Based on fi eld observed traffi c data, a multiple regression noise prediction model was developed by considering all major causative factors. In the process of model development, a mean standard error of 2.32 dB(A) with r2 value of 0.82 was observed. The validation of the model was done by collecting traffi c data from Mysore city in Karnataka, India. The results of the model validation indicated that the model is accurate to 2.6 dB(A) with r2 value of 0.78. Statistical analysis was also done using the paired t-test technique on predicted and observed noise levels. The results indicated that the t-statistical value of the model is less than the t-critical value. This means that the values predicted by the model fi t signifi cantly with the fi eld observed ones and that the independent variables used in the model provide a better explanation of the dependent variable (Leq). The model developed in this study was also compared with the Federal Highway Administration (FHWA) Traffi c Noise Model from USA and the prediction results indicated that the values obtained from the present model are in good agreement with the fi eld observed values than the FHWA model. Therefore, the present model can be used for managing urban road traffi c noise in the Indian context.

Electrochemical Behavior of API X70 Steel in Hydrogen Sulfide-Containing Solutions

As an attempt to contribute to the understanding of the cor- rosion process of steel by hydrogen sulfi de (H2S), the corro- sion behavior of an X70 pipeline steel immersed in several H2S-containing solutions is analyzed in this work. Linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS) techniques were used in order to charac- terize the corrosion behavior of X70 steel in H2S-containing solutions. Electrochemical parameters such as charge-transfer resistance, Rct, polarization resistance, Rp, and corrosion rate are presented in this work. Additionally, a comparison be- tween static and turbulent fl ow conditions was made in order to describe the corrosion behavior of X70 steel. Turbulent fl ow conditions were controlled using the rotating cylinder electrode (RCE) (at 1,000 rpm) in a saturated H2S solution.