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The present study was focused on the effect of chitosan, a linear amino-polysaccharide, on the properties of handsheets made from bleached kenaf kraft pulp. Chitosan was incorporated into the sheets by three distinct techniques, equilibrium adsorption (pH 5), precipitation (pH 10), and spray application. The chitosan dosages tested were 0.5%, 1%, 1.5%, and 2% based on oven dry pulp. Chitosan was found to increase the dry-strength properties of paper such as tear, burst, and tensile index, but its effectiveness was strongly dependent on the method of addition. Spray application gives superior strength properties, followed by equilibrium adsorption. Chitosan is less effective under alkaline conditions. The results showed that chitosan addition improved the mechanical properties of sheets, but the rate of increase in strength properties was higher from 0% to 0.5% compared to 1% to 1.5% regardless of the treatment techniques. [ABSTRACT FROM AUTHOR]

Karst areas are characterized by extreme heterogeneity and variability of geologic, morphologic, hydrogeologic, hydrologic, hydraulic, ecologic and other parameters in space and time. Therefore, the occurrence of floods under such condition manifests in different forms, intensities, and durations. Heavy precipitation in karst areas leads to a considerable increase in groundwater levels and the activation of temporary springs. Karst fields that have not been properly meliorated are particularly vulnerable to such phenomena and, can remain flooded for several weeks. In Dalmatia, in the southern Croatian region, there are 12 karst poljes with an area larger than 1000 ha, including Dicmanjsko-Bisko polje (1700 ha). Our study presents a conceptual model of the interaction of underground and surface water in the Dicmanjsko-Bisko polje, as well as the process of flooding. The input data were geological mapping and measured precipitation. The paper describes the December 2021 flood in detail. The average 11-day precipitation recorded in the field catchment area was 292 mm, which led to the flooding of 230 ha (approximately 14% of the field area). The main cause of the flooding in the western part of the field was a large amount of surface runoff, resulting in insufficient capacity of the existing drainage channels. In the eastern lowest part of the field, flooding was even more intense due to the insufficient capacity of the sinkhole. The flood caused damage to agricultural lands, infrastructure, and economic facilities. The paper proposes flood mitigation measures. The study is an example of the practical application of karst research, that can be used for different purposes (spatial planning, hydrologic monitoring, modeling hydrogeological processes). [ABSTRACT FROM AUTHOR]

This paper examines precipitation associated with large-scale patterns of water vapor transport in the eastern United States. Daily 4 km gridded precipitation from PRISM (1981–2017) is sorted into a subset according to previously defined patterns of water vapor transport supplying the moisture on each day. These subsets are then analyzed to characterize the precipitation associated with each water vapor transport pattern. While each moisture transport pattern is associated with at least occasional precipitation, with seasonal variations, the highest precipitation averages are issued from near-coastal and coastal moisture transport patterns. Moisture transport patterns emanating from the Gulf of Mexico are associated with highest average precipitation inland. Each pattern has a spatially distinct contribution to annual and seasonal precipitation totals. The water vapor transport patterns of moderate intensity and moderate associated precipitation contribute the most to average annual precipitation. Most moisture transport patterns are associated with statistically significant increases in areas of very heavy precipitation (x ≥ 50 mm). By identifying which atmospheric moisture transport patterns are responsible for increasing areas of very heavy precipitation, and by characterizing the precipitation totals and contribution associated with each, this paper demonstrates the utility of examining precipitation variability through moisture transport patterns. [ABSTRACT FROM AUTHOR]

Copyright of Atmosphere -- Ocean (Taylor & Francis Ltd) is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Understanding the M23C6 carbides precipitation sequence aims to determine a correct heat treatment design in order to optimise the mechanical properties of the Fe-18Cr-8Ni steel. In this paper, the ageing influence at 800°C on the mechanical properties and microstructure of this steel has been studied. The aged material was examined with nanoindentation, macrohardness, scanning electron microscopy, light microscopy, and X-ray diffraction techniques. The hardness test results showed a continuous softening of the Fe-18Cr-8Ni steel when increasing the treatment time up to 6000 minutes. The nanoindentation tests revealed a decrease in the nanohardness of the austenite and M23C6 carbides as the ageing time increased. Before the ageing process, the solution treatment produced completely austenitic steel. After 30 and 60 minutes of ageing, the M23C6 carbides were located at the grain boundaries. The precipitation of the M23C6 carbides within the grains was observed from 300 to 6000 minutes of ageing. The coarsening of the M23C6 carbides occurred at high holding times. [ABSTRACT FROM AUTHOR]

The critical size of clusters is a well-known key quantity for precipitation modelling, especially for nucleation. Classically, its value is obtained from a mean-field model which approximates the free energy of clusters. AKMC simulations rely on a set of physical parameters defined at the microscopic scale, thus the nature of hypotheses is very different from its equivalent in phenomenological models. It has been shown recently than the free energy of clusters as well as other important quantities can be directly extracted from AKMC simulations. Thanks to these advances, the critical size for nucleation can now be derived from such measurements. In practice, one faces various problems depending on the quality of the available information. Thus, one has to adapt the measuring method to the different ranges of cluster size and/or the different stages of precipitation. This paper focuses on three methods, considering the precipitation in concentrated AlLi alloys as a model case to explore the evolution of the critical size versus the physical time, from nucleation to coarsening. [ABSTRACT FROM AUTHOR]

To facilitate its vitrification, a portion of the radioactive wastes currently stored at the Hanford Site will be staged and treated using tank-side operations to render their chemistry compliant with the requirements of Hanford's low-activity waste vitrification facility. Initial sampling of staged feeds indicates that process-water dilution, used to reduce waste feed sodium content to levels acceptable for vitrification (5–6 M Na), may cause precipitation of fine, difficult to settle solids that could affect downstream tank-side filtration and ion-exchange. However, dilution-induced precipitation has not been demonstrated under controlled, rigorous laboratory conditions. This paper presents a set of qualitative and quantitative assessments of dilution-induced precipitation using a nonradioactive, Hanford Tank AP-105 simulated waste. These studies found that dilution of AP-farm waste simulants induced precipitation of up to 150 ppm solids, regardless of whether dilution was done with process water (which contains, among other analytes, naturally occurring Ca and Mg) or deionized water. Naturally occurring process-water analytes appeared to accelerate the rate (and possibly extent) of precipitation. Filtration of diluted waste simulants also found that the precipitated solids challenged prototypic tank-side filter operations; however, the impact to filtration performance was readily managed through waste staging settle/decant operations. [ABSTRACT FROM AUTHOR]

Asphaltene precipitation and deposition in different parts of petroleum industry increase considerably cost and problems in oil production. Due to these facts controlling asphaltene precipitation becomes one of valuable topics for research in petroleum engineering. Utilization of Asphaltene inhibitors is known as one of the dominant methods for controlling asphaltene precipitation so in this paper Adaptive neuro-fuzzy inference system (ANFIS) is joint with Genetic Algorithm (GA) to study effectiveness of asphaltene inhibitors on precipitation in terms of oil and inhibitors properties. In order to prepare and evaluate the ANFIS-GA algorithm, some reliable experimental data were gathered. The obtained results from the comparison shows the coefficient of determination (R2) for training and testing phases are 0.98804 and 0.9916 respectively. The determined indexes and graphical comparisons expresses that ANFIS-GA has enough accuracy and potential to estimate effectiveness of inhibitors on asphaltene precipitation reductions. [ABSTRACT FROM AUTHOR]

Precipitation prediction is central in hydrology and water resources planning and management. This paper introduces a semi-empirical predictive model to predict monthly precipitation and compares its predictive skill with those of machine learning (ML) methods. The stochastic method presented herein estimates monthly precipitation with one-step-ahead prediction properties. The ML predictive skill of the algorithms is evaluated by predicting monthly precipitation relying on the statistical association between precipitation and environmental and topographic factors. The semi-empirical predictive model features non-negative matrix factorization (NMF) for investigating the influence of multiple predictor variables on precipitation. The semi-empirical predictive model's parameters are optimized with the hybrid genetic algorithm (GA) and Levenberg-Marquardt algorithm (LM), or GALMA, yielding a validated model with high predictive skill. The methodologies are illustrated with data from Hubei Province, China, which comprise 27 meteorological station datasets from 1988–2017. The empirical results provide valuable insights for developing semi-empirical rainfall prediction models. [ABSTRACT FROM AUTHOR]

The application of treated wastewater (TWW) via pressurized drip irrigation (DI) systems, specifically micro-irrigation, is an effective solution to mitigate water scarcity. TWW contains a higher concentration of nutrients and microbial activity compared to fresh water (FW) and poses a larger danger of fouling and subsequent clogging to DI systems. The goal of this paper was to characterize the effectiveness of chemical treatments, specifically hydrogen peroxide (H2O2) in preventing clogging in DI systems utilizing secondary (ST) and tertiary (TT)_TWW. A novel field model was employed to compare the flow rate (FR), fouling accumulation and composition in laterals and emitters of different treatments. Under ST_TWW irrigation, control treatment performance quickly declined while regular low concentration H2O2 treatments exhibited the lowest amounts of fouling and maintained nominal FR and coefficient of variation (CV). Shock treatments, defined as periodical applications of concentrated chemicals combined with lateral flushing, were ineffective in maintaining satisfactory irrigation performance. [ABSTRACT FROM AUTHOR]

The effects of drought, a devastating natural disaster, have expanded due to intense global warming. Therefore, studying the spatio-temporal evolution and formation mechanism of drought is urgent and important. In this paper, the standardized precipitation evapotranspiration index (SPEI) of the source region of Yellow River was calculated for the years 1961–2015, and the heuristic segmentation and Modified Mann-Kendall methods were used to study the change points and trends of precipitation, temperature, and SPEI. The empirical orthogonal function was used to study the major modes of the SPEI, and cross wavelet analysis was used to demonstrate the relationship between SPEI and large-scale climate factors. The results initially demonstrated no change point and an insignificant positive trend in precipitation. Temperature revealed a significant increasing trend, and a change point was detected in 1997. SPEI indicated a change point in 1993, and a significant increasing trend was observed thereafter. These findings reveal that drought in the study area is highly related to the El Niño-Southern Oscillation. The North Atlantic and Arctic oscillations caused similar impacts on drought. By comparison, changes in SPEI were slightly related to the Pacific decadal oscillation. These results provide useful information for evaluating drought changes in the study area, early warning of drought, and water resource management. [ABSTRACT FROM AUTHOR]

The high concentration of ammonium chloride in the wastewater from the precipitation of rare earth carbonate was studied by an electrolytic method in this paper. The decomposition rate of ammonium chloride is obtained by electrolysis experiment, and the main components of wastewater can be transformed into raw and auxiliary materials that can be reused in the rare earth smelting process, so as to achieve the purpose of treating rare earth carbonate precipitation wastewater and provide a new method for the treatment of rare earth carbonate precipitation wastewater. The principle of the electrolysis process is analyzed in this study, and the optimum electrolysis factor is determined by the condition experiment. The changes in membrane materials and electrode materials before and after use are discussed. The experiments of stripping ammonia water and the reaction conditions of the formation experiment of ammonium bicarbonate are studied. The rare earth carbonate precipitation wastewater with the initial ammonium chloride concentration of 50 g/L was electrolyzed. The concentration of ammonia chloride was reduced to 3.5 g/L after electrolysis, and the electrolysis rate exceeded 90%. The purity of the ammonium chloride after electrolysis could exceed 93%. No industrial reagent was introduced in the electrolysis process, and no other pollutants were produced. [ABSTRACT FROM AUTHOR]

Asphaltene generally existed in colloidal form in cruds and will precipitate in non-equilibrium conditions. Asphaltene instability may take place in the reservoir leading to permeability damage and contributing to flow restriction issues. It may also occur in production strings and surface facilities causing pipe blockage. Any change in oil composition or pressure and temperature at any stage of production will destabilize crude oil producing asphaltene precipitation. In this paper, the stability of target crude oil under the influence of a direct current and contacting with polar fluid, water, is investigated. The amount of the asphaltene deposit and its electrical charge at various operating conditions are investigated. The fact that deposits form on the anode surface proves that asphaltene particles possess a positive charge. The amounts of asphaltenes precipitation were increased considerably by increasing water as polar component. [ABSTRACT FROM AUTHOR]

In this paper, the precipitation behaviour of γ′ phases during cooling after solution treatment has been investigated. An experimental superalloy with a large γ′ volume fraction was employed, and the average cooling rate was ca. 5°C min−1. In order to investigate the forming of precipitates at different temperature stages, interrupt quenching was used during the cooling process. As the results show, the γ′ precipitates change from monomodal to multimodal size distributions with quenching temperature. On the one hand, the large γ′ phases were mainly formed by coalescing and merging. On the other hand, small γ′ in the matrix were continuously precipitated during the cooling process, and the nucleation was not shut off until quenching at 1100°C. The precipitation mechanism is also discussed in this paper. [ABSTRACT FROM AUTHOR]

This paper examines the long-run and short-run impact of changes in temperature and precipitation on tourist arrivals in Mauritius. In this study, the bounds testing approach to cointegration is used. The autoregressive distributed lag model is applied on yearly time series data over the period 1980–2017. The main findings show that precipitation level as proxied by rainfall negatively affect tourist arrivals in both the short run and long run while the temperature is an insignificant factor. Moreover, an increase in the income of tourists and hotel rooms availability is seen to increase tourist arrivals. However, high domestic prices discourage tourists from visiting the island. The findings further confirm the stability of the model for the small island developing state of Mauritius. [ABSTRACT FROM AUTHOR]

Depending on the particle used to irradiate Fe–Cr alloys, at the same dose and temperature, α′ precipitation may occur or not. This paper aims at explaining the origin of the absence of α′ precipitation under ion irradiation. A Fe–15at.%Cr alloy was irradiated with 2 MeV Fe2+ions at 300°C and analysed using atom probe tomography. For the first time to our knowledge, α′ particles were observed under ion irradiation. The characterisation of the α/α′ decomposition with depth showed that injected Fe strongly reduced α′ precipitation. They might have played a major role in the absence of α′ precipitation under ion irradiation. IMPACT STATEMENT This paper reports the first observation of α′ precipitation in Fe–Cr alloys after heavy ion irradiation and demonstrates that the injected interstitial effect drastically modifies the precipitation behaviour. [ABSTRACT FROM PUBLISHER]

This paper uses daily data from 43 police districts across New Zealand from 2000 to 2008 and employs panel econometric techniques to investigate the effect of weather on crime. Temperature and precipitation are found to have a significant effect on the number of violent crimes recorded, and temperature also affects the number of property crimes recorded. As an extension, the common belief that the Nor'wester wind causes ‘disorderly’ behavior is empirically investigated. Studies of this nature are important for the allocation of police resources. [ABSTRACT FROM AUTHOR]

This paper addresses warm season hydroclimatic variability in the southern Appalachian region of the southeastern U.S., where precipitation can vary as much as 127 mm or more, with maximum seasonal totals exceeding 736 mm in extreme cases. Despite the occurrence of droughts, floods, and their socioecological impacts, hydroclimate variability is still poorly understood. This study characterizes the regional scale variations in the hydroclimate by examining the daily distribution of precipitation patterns in different topographic environments. Parameter-elevation relationships on independent slopes model (PRISM) gridded precipitation estimates are used to identify the location and frequency of different types of rainfall events. Several types of clustering algorithms are used as a regionalization approach to define areas where the precipitation regime exhibits similarities in its frequency of occurrence. The results are compared with internal validation statistics and a visualization is used to assess how well the resulting hydroclimatic regions align with different topographic environments. This study reveals the intricate spatial footprint of dry and wet regimes and demonstrates how clustering applications can be used with gridded climate data to determine where extremes are most likely to develop across mountain catchments. [ABSTRACT FROM AUTHOR]

The paper evaluates long-term seasonal variations of the deuterium excess (d-excess = δ2H - 8... δ18O) in precipitation of stations located north and south of the main ridge of the Austrian Alps. It demonstrates that sub-cloud evaporation during precipitation and continental moisture recycling are local, respectively, regional processes controlling these variations. In general, sub-cloud evaporation decreases and moisture recycling increases the d-excess. Therefore, evaluation of d-excess variations in terms of moisture recycling, the main aim of this paper, includes determination of the effect of sub-cloud evaporation. Since sub-cloud evaporation is governed by saturation deficit and distance between cloud base and the ground, its effect on the d-excess is expected to be lower at mountain than at lowland/valley stations. To determine quantitatively this difference, we examined long-term seasonal d-excess variations measured at three selected mountain and adjoining valley stations. The altitude differences between mountain and valley stations ranged from 470 to 1665 m. Adapting the 'falling water drop' model by Stewart [J. Geophys. Res., 80(9), 1133-1146 (1975).], we estimated that the long-term average of sub-cloud evaporation at the selected mountain stations (altitudes between about 1600 and 2250 m.a.s.l.) is less than 1 % of the precipitation and causes a decrease of the d-excess of less than 2 ‰. For the selected valley stations, the corresponding evaporated fraction is at maximum 7 % and the difference in d-excess ranges up to 8 ‰. The estimated d-excess differences have been used to correct the measured long-term d-excess values at the selected stations. Finally, the corresponding fraction of water vapour has been estimated that recycled by evaporation of surface water including soil water from the ground. For the two mountain stations Patscherkofel and Feuerkogel, which are located north of the main ridge of the Alps, the maximum seasonal change of the corrected d-excess (July/August) has been estimated to be between 5 and 6 ‰, and the corresponding recycled fraction between 2.5-3 % of the local precipitation. It has been found that the estimated recycled fractions are in good agreement with values derived from other approaches. [ABSTRACT FROM AUTHOR]

A comparative study on prediction of water table depth using Back Propagation Neural Network (BPNN) and Adaptive Neuro-Fuzzy Inference System (ANFIS) is addressed in this paper. BPNN and ANFIS models are developed using precipitation, temperature, humidity, surface runoff and evapotranspiration loss to simulate water table depth fluctuations at Rengali, Odisha. Multiple linear regressions have been applied to observe the correlation between the dependent variable i.e. water table depth and the independent variables i.e. precipitation, temperature, humidity, surface runoff and evapotranspiration losses. Six different types of membership functions for ANFIS and three different transfer functions in case of BPNN are employed to compare the results of the models to predict water table depth. The model considering the physical parameters- precipitation, average temperature, evapotranspiration losses and humidity shows better performances on ANFIS as compared to BPNN. BPNN model using purelin transfer function produced best result with MAE testing 0.189701, RMSE testing 0.209842, and R2 testing 0.8512. ANFIS model with gauss2 membership function as input mf presented a superior ability to predict water table depth fluctuation over BPNN with MAE testing 0.080684, RMSE testing 0.089129, and R2 testing 0.9671. Taken as a whole, ANFIS is superior to BPNN for predicting water table depth. [ABSTRACT FROM AUTHOR]

This paper presents a review of the bubble column evaporator (BCE) and its many novel applications. The BCE process offers a continuously produced source of high air–water interface and consequently provides high overall heat and mass transfer coefficients. Although the bubbling process itself is both simple to use and apply, our understanding of the fundamental physical and chemical principles involved is surprisingly limited and there are many issues yet to be explained. Recently the process has been used to develop new methods for the precise determination of enthalpies of vaporisation (?Hvap) of concentrated salt solutions, as an evaporative cooling system, a sub-boiling thermal desalination unit, for sub-boiling thermal sterilisation, for low temperature thermal decomposition of different solutes in aqueous solution and for the inhibition of particle precipitation in supersaturated solutions. These novel applications can be very useful in many industrial practices, such as desalination, water/waste water treatment, thermolysis of ammonium bicarbonate (NH4HCO3) for the regeneration in forward osmosis and refrigeration related industries. The background theories and models used to explain the BCE process are also reviewed and this fundamental knowledge is applied to the design of BCE systems and to explain recently explored applications, as well as potential improvements. Many other prospective applications of the BCE process are also reported in this paper. [ABSTRACT FROM AUTHOR]

Accurate estimations of spatio-temporal fields at unsampled locations are important in a number of applications. Often, spatio-temporal fields are advected, which means the change in field values over time at a particular point in space stems to a large extent from motion of a more or less constant spatial field. For such dynamic fields, interpolation methods including information on the motion behaviour of the field are promising extensions of solely spatial (snapshot) and symmetric spatio-temporal methods. In this paper, the performance of different deterministic and geostatistical interpolation methods is compared for precipitation estimation from 1-minute time series of spatially distributed rain gauges. The focus is on spatio-temporal methods that include information on the motion behaviour of the rainfield, estimated from weather radar using optical flow. The different interpolation methods are introduced and evaluated using rain gauge measurements of a 15-day period and cross-validation. The results show that including information on the motion behaviour significantly improves interpolation quality in terms of RMSE. [ABSTRACT FROM PUBLISHER]

Lignin of high purity can be separated from black liquor using the LignoBoost process, of which the overall efficiency is largely dependent on the precipitation yield of lignin, which depends on the properties of black liquor and process conditions. In this paper, the influences of process conditions on the precipitation yield of lignin from mixed hardwood/softwood black liquor were investigated. The Klason and standard UV method were used to determine lignin concentration. The chemical and structural properties of lignin were also analyzed. The results showed that the precipitation yield of lignin increased along with a decrease in pH and temperature, or with an increase in the ion strength of black liquor, and the yield was lower when mixed softwood/hardwood black liquor was used. It also showed that at a higher precipitation yield the precipitated lignin had a lower average molecular weight but had higher methoxyl and phenolic hydroxyl content. [ABSTRACT FROM PUBLISHER]

In a recent paper, the authors showed how the clusters free energies are constrained by the coagulation probability, and explained various anomalies observed during the precipitation kinetics in concentrated alloys. This coagulation probability appeared to be a too complex function to be accurately predicted knowing only the cluster distribution in Cluster Dynamics (CD). Using atomistic Monte Carlo (MC) simulations, it is shown that during a transformation at constant temperature, after a short transient regime, the transformation occurs at quasi-equilibrium. It is proposed to use MC simulations until the system quasi-equilibrates then to switch to CD which is mean field but not limited by a box size like MC. In this paper, we explain how to take into account the information available before the quasi-equilibrium state to establish guidelines to safely predict the cluster free energies. [ABSTRACT FROM PUBLISHER]

Precipitation strategy of struvite-family crystals is presented in this paper to recover phosphate and potassium from a synthetic wastewater in the presence of citric acid at elevated temperature. The crystal-forming solutions were prepared from crystals of MgCl2and NH4H2PO4with a molar ratio of 1:1:1 for Mg+2,, and, and the citric acid (C6H8O7) was prepared (1.00 and 20.00 ppm) from citric acid crystals. The Rietveld analysis of X-ray powder diffraction pattern confirmed a mixed product of struvite, struvite-(K), and newberyite crystallized at 30°C in the absence of citric acid. In the presence of citric acid at 30° and 40°C, an abundance of struvite and struvite-(K) were observed. A minute impurity of sylvite and potassium peroxide was unexpectedly found in certain precipitates. The crystal solids have irregular flake-shaped morphology, as shown by scanning electron microscopy micrograph. All parameters (citric acid, temperature, pH, Mg/P, and N/P) were deliberately arranged to control struvite-family crystals precipitation. [ABSTRACT FROM PUBLISHER]

This paper focus on the main influence factors (temperature, pressure, and mass fraction of CO2) on the state of asphaltene in the crude oil during CO2flooding by using high temperature and high pressure microanalysis system of solid precipitation. For the simulated oil sample – CO2system, the state of asphaltene is not affected by temperature within this range of 50°C to 100°C, the particle size of the asphaltene has an increase with the increase of the pressure from 8MPa to 40 MPa. When the mass fraction of CO2is less than 35%, the state of the asphaltene has not changed and the asphaltene particles are in a suspension state. When the mass fraction of CO2increases to 40%, the aggregation of the asphaltenes occurs and then form precipitation. With the further increase of the mass fraction of CO2, the particle of the asphaltene aggregates has a significant increase. For the field development project design of CO2flooding, the influence of the temperature can be ignored, the appropriate mass fraction of CO2is below 35% and the gas injection pressure should maintain a relatively low value. The results can provide a theoretical basis to avoid the asphaltene precipitation during CO2flooding. [ABSTRACT FROM AUTHOR]

The identification of homogeneous precipitation regions has value in many water resources engineering applications (infrastructure planning, design, operations; climate forecasting, modelling). The objective of this paper is to assess the sensitivity of precipitation regions to the temporal resolution (monthly, seasonal, annual and the annual maximum series) of the data. The presented method uses the fuzzyc-means clustering algorithm to partition climate sites into statistically homogeneous precipitation regions. The regions are validated using an approach based on L-moment statistics. The method is conducted in two climatically different study areas in western and eastern Canada. There does not appear to be a relationship between the spatial distributions of the regions formed using different temporal resolutions of the precipitation data. It is recommended to delineate precipitation regions that are specific to the task at hand, and to select a temporal resolution that is consistent with the final application of the regional precipitation dataset.EDITOR A. Castellarin; ASSOCIATE EDITOR T. Kjeldsen [ABSTRACT FROM PUBLISHER]

Industrial production operations generate huge amounts of heavy metals enriched sludge. Due to inadequate management and illegal disposal practices, this waste sludge can deteriorate human and environmental health. For sustainable environmental development and conserving human health, sludge should be recycled to recover the heavy metals and the treated sludge (with permissible or safe limits of heavy metals) should be used to improve the soil fertility and physical properties. Herein, a study is carried out to identify the optimum concentration of sulphuric acid (H2SO4) to remove copper (Cu), nickel (Ni) and chromium (Cr) from the waste sludge and the number of organic matter residues that remained after the acid digestion. Besides, the optimum pH to precipitate Cu, Ni, and dissolute the Cr in the form of metal hydroxide is determined. Acid digestion is done by using H2SO4 and precipitation is done by sodium hydroxide (NaOH). The heavy metals concentrations were determined through inductively coupled plasma-optical emission spectroscopy (ICP-OES). The result showed that the concentration of H2SO4 is significantly affecting the sludge organic content. The respective percentage of Cu, Ni and Cr removed by 30% of H2SO4 were 98.99, 99.27 and 97.22%. At pH 14, Cu, Ni and Cr precipitation to form metal hydroxide was the highest. About 4.01%, 23.75% and 13.93% of copper hydroxide, nickel hydroxide and chromium hydroxide are, respectively, precipitated out. However, slight dissolution occurred due to the nature solubility of metal hydroxide. [ABSTRACT FROM AUTHOR]

Intense precipitation may occur in high-temperature materials during service. This precipitation significantly affects the mechanical properties. Coarse precipitates can reduce ductility and toughness dramatically. To investigate the phenomenon, precipitation in the austenitic stainless steel AISI 310 is quantified in a parallel paper. The samples were aged up to 5000 h at 800°C. Especially, σ-phase and M23C6-carbides were analysed. A model for the influence of coarse particles on ductility has been developed and successfully applied to the measured values. A model due to Chen and Mott has been used to compute the effect of particles on toughness. A satisfactory agreement with the observations was obtained. [ABSTRACT FROM AUTHOR]

Copyright of Hydrological Sciences Journal/Journal des Sciences Hydrologiques is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The identification of homogeneous precipitation regions is essential in the planning, design and management of water resources systems. Regions are identified using a technique that partitions climate sites into groups based on the similarity of their attributes; the procedure is known as regionalization. In this paper the ability of four attribute sets to form large, coherent precipitation zones is assessed in terms of the regional homogeneity of precipitation statistics and computational efficiency. The outcomes provide guidance for effective attribute selection for future studies in Canada. The attributes under consideration include location parameters (latitude, longitude), distance to major water bodies, site elevation and atmospheric variables modelled at different pressure levels. The analysis is conducted in two diverse climate regions within Canada including the Prairie and the Great Lakes–St Lawrence lowlands regions. The method consists of four main steps: (i) formation of the attribute sets; (ii) determination of the preferred number of regions (selection of thec-value) into which the sites are partitioned; (iii) regionalization of climate sites using the fuzzyc-means clustering algorithm; and (iv) validation of regional homogeneity usingL-moment statistics. The results of the attribute formation,c-value selection, regionalization and validation processes are presented and discussed in a comparative analysis. Based on the results it is recommended for both regions to use location parameters including latitude, longitude and distance to water bodies (in the Great Lakes region) to form precipitation regions and to consider atmospheric variables for future (climate change) applications of the regionalization procedure. [ABSTRACT FROM PUBLISHER]

Among various flow assurance problems, asphaltene precipitation is a major issue. This study aims to evaluate the potential application of silica-polyacrylamide nanocomposite to inhibit asphaltene precipitation for the first time. The nanocomposites were synthesized and characterized by Fourier transform infrared and field emission scanning electron microscopy techniques. The inhibitory effect of nanocomposites in water-based nanofluid on two unstable crude oils was evaluated using viscometry, asphaltene dispersion test, dynamic light scattering, and polarized microscopy techniques. The viscosity measurements indicate that nanocomposites postpone asphaltene onset of precipitation from 34 to 44 and 23 to 36 vol% nC7 for crude oil A and B, respectively. The maximum dispersion efficiency of nanocomposite was 69% and 79% at the 1% and 2.5% nanofluid volume dosages for crude oil A and B, respectively. Dynamic Light Scattering and microscopy results indicated the asphaltene size change to lower values in the presence of nanocomposites. Polyacrylamide attached to the silica surface promotes a surface with efficient functional groups that increase the asphaltene adsorption. Asphaltene adsorption leads to decreased aggregate size and controlling the asphaltene precipitation. The prepared nanocomposite was evaluated as an efficient dispersant and inhibitor that reveals the potential application of Silica-polyacrylamide for handling the asphaltene precipitation in reservoirs. [ABSTRACT FROM AUTHOR]

It is well known that a Cu/Li ratio over 4.0 leads to significant precipitation hardening in the third generation of Al–Li alloys, which have been widely used in aerospace and aeronautic industries. However, increasing Cu levels not only cancels some gains in weight reduction but also results in reductions in ductility when the traditional age-hardening process is adopted. In this study, we show that higher strength and ductility can be achieved simultaneously by replacing traditional artificial aging with new creep aging and tailoring the entire process from casting to age hardening without changing any nominal chemical compositions. Surprisingly, the precipitation kinetics of AA2060 alloy is significantly enhanced through the combination of hot extrusion, creep aging, and pre-strain compared to traditional artificial aging. For example, at 160°C, it follows the transformation path of supersaturated solid solution (SSSS)→GP zones + δ′+T1 precursors which will further transform into T1 +S'; at 200°C, SSS→ GP zones, and they transform into T1 + S' immediately. The precipitation of θ′ and δ′ phases is significantly inhibited at elevated temperatures due to the competing relationship with T1 and S' phases at a peak-aged state. Contrary to traditional knowledge in Al–Li alloys, we have found that the greater extrusion ratio at 33.0 and higher aging temperature at 200°C can give a much higher peak aging strength with average ultimate tensile strength 659 MPa. [ABSTRACT FROM AUTHOR]

The Wei River Basin is a typical arid and semi-arid area of the Yellow River Basin. Quantitative estimates of the contributions of human activities and climate changes in this region will enhance our understanding of the local hydrological mechanism and provide an effective reference for other arid and semi-arid areas of the world in local water resource planning and management. The heuristic segmentation method was used to detect the inflection points of the annual runoff. The slope change ratio of accumulative quantity (SCRAQ) method was applied to compute the relative contributions of human activities and climate changes to the decreasing runoff in the whole basin and the basin above Linjiacun. For the whole basin, when 1960–1969 is selected as the baseline, the contributions of climate changes and human activities in 1970–1993 are 26.47% and 73.53%, respectively, those in 1993–2005 are 23.33% and 76.67%, respectively. When 1970–1993 is selected as the baseline, the contributions of climate and human impacts in 1994–2005 are 18.88% and 81.12%, respectively. The results imply that human activities are the dominant driving factors of runoff reduction, whose effect is increasingly intensifying. Furthermore, in order to verify the contributions of human activities and climate changes based on the SCRAQ method, an approach based on the Budyko hypothesis was used in this paper. The results indicate that the contributions of human activities and climate changes based on the SCRAQ method are consistent with those based on the sensitivity-based method.Editor Z.W. Kundzewicz; Associate editor D. Yang [ABSTRACT FROM PUBLISHER]

In a series of papers aimed at better understanding precipitation in binary alloys, it was shown that Cluster Dynamics (CD) is a valuable tool to bridge the gap between microscopic and macroscopic scales, provided that cluster-free energies are carefully derived from Monte Carlo calculations. Indeed, in such conditions, CD predictions compare well with Atomistic Kinetic MC simulations. Nevertheless, in a recent work, the authors pointed out some limitations of this approach at high solute concentration. The present work aims at revisiting the notion of cluster-free energy in the context of concentrated solid solutions at thermal equilibrium. [ABSTRACT FROM AUTHOR]

This paper reports the feasibility of nano-oxide precipitate formation in Fe–Cr alloy by ion implantation synthesis. High contents of Al+and O+ions were implanted into thin films of high purity Fe–10%Cr alloy at room temperature and were studied by transmission electron microscopy (TEM) and atom probe tomography (APT). In contrast, to the common two-stage implantation/annealing scheme of precipitate ensemble synthesis by ion beams, cluster formation took place at the implantation stage in our study, requiring no subsequent high-temperature annealing. The post-implantation microstructural examination revealed in the as-implanted thin foil an array of precipitates with diameters in the range of 3–30 nm. The precipitate number density distribution was found to depend on the foil thickness. The precipitate enrichment with both Al and O was confirmed by the energy-filtered TEM analysis. Judging from the electron diffraction pattern and high-resolution TEM analysis, the crystal lattice of precipitates corresponds to some cubic modification of aluminium-rich oxide or pure aluminium oxide. The precipitate lattice alignment with the host matrix was revealed for at least a part of precipitates. The analysis of APT data using cluster detection algorithm indicates the presence of local zones enriched in Al and O, even in those areas of as-implanted samples where no clusters were visible by TEM. [ABSTRACT FROM PUBLISHER]

This paper investigated the effect of different amounts of Ag addition on the microstructure, properties and precipitation processes of Al–4.6Cu–6.9Mg(wt-%) alloy using various analytical methods. It was found that Ag addition stimulated new X 9 and V phases precipitated finely and dispersively in the matrix, as a result of Mg–Ag co-clusters; the volume fraction of precipitates increased with the content of Ag addition. Such precipitation improved the mechanical performance of the Al–Cu–Mg alloy significantly. The mechanism for the formation of new precipitates is also described in this paper. [ABSTRACT FROM AUTHOR]

This paper presents the application of the advanced probabilistic slope stability model with precipitation effects developed to assess the performance of small homogeneous earthfill embankment dam slopes, when exposed to future seasonal precipitation scenarios. Here, the UK's latest probabilistic climate model known as UKCP09 is applied. To reflect the critical conditions conducive to slope failure, a benchmark has been developed to identify the change, if any, in the risk classification of the slope's performance level due to precipitation. Thus, enabling the reassessment of the dam's risk classification, as categorised by the Flood and Water Management Act 2010. Such an approach could therefore be well placed to support and enhance the decision-making process, its impact on the public, especially in relation to future climate effects. [ABSTRACT FROM AUTHOR]

Experience has shown the important influence of rainstorm water in the arrival of pollutants to receiving water bodies. This paper presents an identification of rain gauge stations and rainstorm variables with influence over water quality parameters such as Temperature, Conductivity, pH and COD, measured in the effluent of an urban catchment. Fourteen rainfall events registered by eight rain gauge stations within or in the proximity of the studied catchment (El Salitre Basin, Bogotá, Colombia) were analysed by the use of correlation tests and Kernel Classificatory methods. Some sensitive water quality parameters to rainfall (maximum rainfall height, mean of height, total height; during a rainstorm event) were identified (pH, temperature, conductivity and settleable solids). Correlations were significant mainly for two rain gauge stations in the proximity (about 5 km) of the effluent and two others near the eastern mountains of the city (zone with high slopes). [ABSTRACT FROM AUTHOR]

Chemical acid leaching is an effective technique for extracting toxic metals from the finest fractions of polluted soils. Nevertheless, the use of large quantities of reagents and process water results in prohibitive operating costs. The purpose of this study was to evaluate the technical and economic advantages of recirculating water in a counter-current leaching process (CCLP). Five 1-h sulfuric acid extraction steps (at pH = 1.5) followed by three 5-min water-washing steps were applied to the fine particle fraction (<0.125 mm) of an industrial soil polluted by Cd (13.2 mg·kg−1), Cu (3 100 mg·kg−1), Mn (685 mg kg−1), Pb (550 mg·kg−1), and Zn (2 840 mg·kg−1). The leaching experiments were carried out at ambient temperature using a 10% soil suspension and in 1-L working volume stirred tank reactors. This paper presents results of conventional and counter-current leaching process (CCLP) tests and shows that the CCLP yields removal results for Cu (85%), Zn (86%), Mn (75%), and Cd (90%) that are similar to those obtained using the conventional leaching process. Moreover, the CCLP uses half of the quantity of acid and one-eighth of the amount of water that the conventional process uses. Metal precipitation with NaOH and Ca(OH)2was applied to treat the acidic leachates, and good metal removal yields were achieved with both reagents. However, the large consumption of chemicals implies high operating costs. In addition, the precipitation causes considerable sludge production, particularly when using Ca(OH)2. Overall, the CCLP coupled to metal precipitation using NaOH and water recycling appears to be the most attractive option for the removal of toxic metals from this industrial soil. [ABSTRACT FROM AUTHOR]

Copyright of Hydrological Sciences Journal/Journal des Sciences Hydrologiques is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Hydrological Sciences Journal/Journal des Sciences Hydrologiques is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Impact models investigating climate change effects on food safety often need detailed climate data. The aim of this study was to select climate change projection data for selected crop phenology and mycotoxin impact models. Using the ENSEMBLES database of climate model output, this study illustrates how the projected climate change signal of important variables as temperature, precipitation and relative humidity depends on the choice of the climate model. Using climate change projections from at least two different climate models is recommended to account for model uncertainty. To make the climate projections suitable for impact analysis at the local scale a weather generator approach was adopted. As the weather generator did not treat all the necessary variables, an ad-hoc statistical method was developed to synthesise realistic values of missing variables. The method is presented in this paper, applied to relative humidity, but it could be adopted to other variables if needed. [ABSTRACT FROM PUBLISHER]

Extensive precipitation can occur in high temperature materials during service. This is known to significantly affect the mechanical properties. To be able to study this phenomenon, particle formation in the austenitic stainless steel 310 has been quantified. In particular, σ-phase and M23C6-carbides have been analysed. Specimens have been aged up to 5000 h at 800°C. The precipitation of the two phases has been modelled. The basis of the model is diffusion-controlled growth. σ-phase shows a spherical growth and an M23C6 planar growth. The soft impingement of the diffusion zones with respect to both chromium and carbon is taken into account. The influence on mechanical properties is analysed in a parallel paper. [ABSTRACT FROM AUTHOR]

Radars at different frequencies have been used over five decades for observing precipitation. S and C bands have been employed for long range coverage observations. Dual-polarization X-band radars have been shown to be useful for networked applications. Space borne precipitation radars have been at Ku band, or higher frequencies such as Ka, as in the GPM mission. This paper presents a comprehensive and unified view of radar precipitation observations at these bands, highlighting the advantages, limitations and the specific applications associated to them. Moreover, relationships between radar measurements at different bands in rain are illustrated. Examples of their use to predict attenuation margin and to simulate observations of the dual polarization, dual frequency Ku and Ka scanning radar D3R to be used in the ground validation program of the GPM mission are shown. [ABSTRACT FROM AUTHOR]

Copyright of Hydrological Sciences Journal/Journal des Sciences Hydrologiques is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

There have, so far, been no papers about the detoxification effects on morphine-dependent animals of a mixture of cis-sec-butyl-1-propoenyl disulphide and trans-sec-butyl-1-propoenyl disulphide (SBD), which is isolated from crude essential oil of Ferula sinkiangensis K.M. Shen, a Chinese traditional herbal medicine. Naloxone-precipitated abstinent morphine-dependent models and naturally abstinent morphine-dependent models were used to evaluate the detoxification effects of intraperitoneal injection of SBD. In addition, the writhing test for mice was used to assess the anti-nociceptive effects of SBD, and the spontaneous activity test was used to verify the sedative effects of SBD. Acute toxicity tests of the SBD in mice were performed and the LD50 values were calculated. The results indicated that SBD can inhibit the abstinent syndromes, and that SBD had good anti-nociceptive and sedative effects. [ABSTRACT FROM AUTHOR]

Copyright of Hydrological Sciences Journal/Journal des Sciences Hydrologiques is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Records of precipitation extremes are essential for hydrological design. In urban hydrology, intensity-duration-frequency curves are typically estimated from observation records. However, conventional approaches seldom consider the areal extent of events. If they do, duration-dependent area reduction factors are used, but precipitation is measured at only a few locations. Due to the high spatial variability of precipitation, it is relatively unlikely that a gauged observation network will capture the extremes that occur during a precipitation event. Therefore, the area reduction approach cannot be regarded as the reduction of an observed maximum. To investigate precipitation extremes, spatial aspects need to be considered using different approaches. Here, we both address the conventional practice of area reduction and consider a within-area chance of increased precipitation, defined as the maximum precipitation intensity observed in a cluster within a selected domain. The results show that (1) the risk of urban flooding is routinely underestimated in current design practice, and (2) traditional calculations underestimate extremes by as much as 30-50%. We show how they can be revised sensibly. [ABSTRACT FROM AUTHOR]

Copyright of Hydrological Sciences Journal/Journal des Sciences Hydrologiques is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)