Scale Dispersion Research Articles

Modeling air concentrations and risk of carcinogens and co–carcinogens in Gibraltar and source apportionment of nearby industrial facilities

Airborne exposures of carcinogenic and co–carcinogenic pollutants, emitted from industries and various diffuse sources in a 10km radius of Gibraltar, were calculated at the west side of the Rock of Gibraltar facing the Bay. 2005 and 2008 industrial annual emission rates reported to E–PRTR and 2005 municipal diffuse annual emission rates were entered in OML–Multi, a multi–source version of an atmospheric Gaussian plume local scale dispersion model. The model results reveal that carcinogens PAH, represented by benzo[a]pyrene (BaP), arsenic and nickel, and potentially chromium are the priority pollutants with respect to human cancer risk and that the contribution from industrial sources on the Spanish coastal area exceeds that from the diffuse sources from adjacent Spanish municipalities. There is a decrease in annual mean air concentrations from industrial emissions between the years 2005 and 2008. The assessment of contribution to the Gibraltar air concentrations of the priority pollutants from industrial sources shows that refinery CEPSA, chemical industry Petresa and petroleum industry Lubricantes del Sur are significant for nickel. Chemical industry Interquisa is significant for PAHs with a notable decrease in PAH emissions from 2006 to 2007, whereas the contribution from CEPSA is more constant. For arsenic only CEPSA shows a continuous trend and contributes to the 2008 air concentration together with sewerage Edar de la Linea de la Concepcion. CEPSA and metal industry Acerinox contribute the most to the chromium air concentrations. NO2/NOx is the most critical co–carcinogen and electricity plant Central Termica Los Barrios, CEPSA, electricity plant Generacion Electrica Peninsular and electricity plant Cogeneracion de Interquisa are the most significant contributors to the air concentrations in Gibraltar. Pollutant contributions from CEPSA flaring, ship traffic in the Bay and Strait, local road traffic and local diesel generators are currently un–quantified.

Co-benefits of climate change mitigation policies on health: a case study in Suzhou City, China

Background Economic expansion in China recentlyhas mainly relied on consumption of fossil fuel, which has led to dramatic increases in air pollutants and greenhouse gases emissions. China’s cities are now facing the worst problems of air pollution and energy consumption in the world. Combined with high density of population in urban areas, urban residents are at significant and increasing health risk. Local city governments have already proposed various policies to reduce energy consumption and air pollution which may also produce co-benefits on public health. Aims The aim was to develop a methodology and apply it to assess co-benefit of climate change mitigation policies on health in a case city of Suzhou, China. Methods Air pollutant concentrations of Suzhou urban area were modelled using traffic and city scale dispersion models (OSPM/CALINE 4 and CMAQ) coupledwith monitored air quality data. Population density and resident time activity diary (TAD) data have been incorporated with air quality data to calculate the exposure of urban resident to PM10/PM2.5 in Suzhou city for the period 2006-2010. Health impacts have beencalculated using published exposure-response functions in China. Results GIS-based exposure assessment methods which can assess air pollution exposures at various scales have been designed for Chinese cities. They have been appliedto assess the health impact of air pollution in Suzhou urban area during the period 2006-2010. Conclusions Although the emissions of air pollutants and greenhouse gases have increased in Suzhou during the period 2006-2010, policies have slowed the exponential increase of these emissions and have avoided air quality deteriorating so quickly. Quantitative results of the effect of major climate change mitigation policies on air pollution and thus population health will be presented. We also recommend which of the climate change policy options are most successful to avoid adverse health impacts for Chinese cities.

Synthesis, Characterization and Properties of the IA / SAS Copolymer

A copolymer was prepared from itaconic acid (IA) and sodium allysulfonate (SAS). The structure of the IA/SAS copolymer was characterized by the means of FTIR. The performances of scale inhibition, dispersion and biodegradability of the IA/SAS copolymer were studied. The results showed that the IA/SAS copolymer had good scale inhibition and dispersing performance. The scale inhibition rate on calcium carbonate was 93% when the copolymer was 20 mg·L-1. The scale inhibition rate on calcium phosphate was 92% when the copolymer was 24 mg·L-1. The copolymer had good biodegradation performance and biodegradation rate could reach 69.5% after 28 days.

A botanical polysaccharide extracted from abandoned corn stalks: Modification and evaluation of its scale inhibition and dispersion performance

A botanical hetero-polysaccharide sulfonated salt was prepared with hetero-polysaccharide extracted from abandoned corn stalks and cheap starting materials such as epichlorohydrin, and sodium bisulfite commercially available. The structures were characterized by FT-IR and 1H-NMR. Then, the novel sulfonated botanical hetero-polysaccharide derivative (PS-NAEP) was employed as an anti-scaling and dispersing agent. Its scale inhibition performance was evaluated by static test against calcium sulfate and calcium phosphate scaling while the dispersity test was performed for ferric oxide. The impact factors of scale inhibition performance such as agent concentration, pH value, total hardness and temperature, were investigated. The experimental results demonstrated that scale inhibition efficiency of PS-NAEP was close to 95% top against calcium sulfate and 55% against calcium phosphate in the simulation experiment. Scanning electron microscope (SEM) and X ray diffraction (XRD) analysis were also utilized to characterize morphology and crystal form of calcium sulfate and calcium phosphate scale. It appears that the higher scale inhibition efficiency and the worse distortion of the crystal form of calcium sulfate and calcium phosphate are all due to PS-NAEP. Moreover, special dispersion to ferric oxide was studied through observation of light transmittance of the dispersing solution, which suggested PS-NAEP was an effective dispersant.

Oocyte dynamics and reproductive strategy of Aphanopus carbo in the NE Atlantic—Implications for fisheries management

Black scabbardfish is a deep water species of high commercial interest in the NE Atlantic; however the life history and stock structure is poorly understood. For this study, specimens were collected from commercial trawls off west of the British Isles and longliners from the Madeira Islands, between September 2008 and May 2010. Geographical differences in the reproductive state of scabbardfish were evident, supporting the theory of a north-south migration. Only immature specimens were found in the northern area, while in Madeira all maturity stages were observed, with the peak spawning in October–November. Consistently, the gonadosomatic index (GSI) showed an increase throughout the year, reaching a maximum in October and November for males and females, respectively; while for the northern area the GSI values had low variability. Oocyte development was described and characterized for each maturity stage. Histology revealed that the oocytes have a group-synchronous development and it was concluded that black scabbardfish was a total spawner and had determinate fecundity. The geographical quasi-complete separation of the immature and mature individuals necessitated the use of a novel bias-reduction GLM in the estimation of length at maturity (LC50%). Estimated LC50% for both sexes was significantly higher when data from both areas were combined (females=1156mm, males=1098mm) than using the Madeira dataset (females=1110mm, males=1010mm). The results highlight large scale dispersal in this species which needs to be treated as a highly migratory species and be managed as a single population.

Steady plumes in heterogeneous porous formations: A stochastic Lagrangian approach

Key Points Steady concentration (C) field in heterogeneous formations is analyzed Analytical solutions for the mean and variance of C are developed Local scale dispersion exerts a great influence on both C moments

Distribution function approach to redshift space distortions. Part IV: perturbation theory applied to dark matter

We develop a perturbative approach to redshift space distortions (RSD) using the phase space distribution function approach and apply it to the dark matter redshift space power spectrum and its moments. RSD can be written as a sum over density weighted velocity moments correlators, with the lowest order being density, momentum density and stress energy density. We use standard and extended perturbation theory (PT) to determine their auto and cross correlators, comparing them to N-body simulations. We show which of the terms can be modeled well with the standard PT and whichneed additional terms that include higher order corrections which cannot be modeled in PT. Most of these additional terms are related to the small scale velocity dispersion effects, the so called finger of god (FoG) effects,which affect some, but not all, of the terms in this expansion, and which can be approximately modeled using a simple physically motivated ansatz such as the halo model. We point out that there are several velocity dispersions that enter into thedetailed RSD analysis with very different amplitudes, which can be approximately predicted by the halo model. In contrast to previous models our approach systematically includes all of the termsat a given order in PT and provides a physical interpretation for the small scale dispersion values. We investigate RSD power spectrum as a function of μ, the cosine of the angle between the Fourier mode and line of sight, focusing on the lowest order powers of μ and multipole momentswhich dominate the observable RSD power spectrum. Overall we find considerable success in modeling many, but not all, of the terms in this expansion. This is similar to the situation in real space, but predicting power spectrum in redshift spaceis more difficult because of the explicit influence of small scale dispersion type effects in RSD, which extend to very large scales.

Effect of Mean Network Coordination Number on Dispersivity Characteristics

In this study, we investigate the role of topology on the macroscopic (centimeter scale) dispersion characteristics derived from pore-network models. We consider 3D random porous networks extracted from a regular cubic lattice with coordination number distributed in accordance with real porous structures. We use physically consistent rules including ideal mixing in pore bodies, molecular diffusion, and Taylor dispersion in pore throats to simulate transport at the pore-scale level. Fundamental properties of porous networks are based on statistical distributions of basic parameters. Theoretical calculations demonstrate strong correspondence with data obtained from numerical experiments. For low coordination numbers, we observe normal transport in porous networks. Anomalous effects expressed by tailing in concentration evolution are seen for higher coordination numbers. We find that the mean network coordination number has significant influence on averaged characteristics of porous networks such as geometric and hydraulic dispersivity, while other topological properties are of less significance. We give an explicit formula that describes the decrease of geometric dispersivity with growing mean coordination number. The results demonstrate the importance of network topology for models for flow and transport in porous media.

Chameleonf(R)gravity in the virialized cluster

Current constraints on $f(R)$ gravity from the large-scale structure are at the verge of penetrating into a region where the modified forces become nonlinearly suppressed. For a consistent treatment of observables at these scales, we study cluster quantities produced in chameleon and linearized Hu-Sawicki $f(R)$ gravity dark matter $N$-body simulations. We find that the standard Navarro-Frenk-White halo density profile and the radial power law for the pseudo-phase-space density provide equally good fits for $f(R)$ clusters as they do in the Newtonian scenario. We give qualitative arguments for why this should be the case. For practical applications, we derive analytic relations, e.g., for the $f(R)$ scalar field, the gravitational potential, and the velocity dispersion as seen within the virialized clusters. These functions are based on three degrees of freedom fitted to simulations, i.e., the characteristic density, scale, and velocity dispersion. We further analyze predictions for these fitting parameters from the gravitational collapse and the Jeans equation, which are found to agree well with the simulations. Our analytic results can be used to consistently constrain chameleon $f(R)$ gravity with future observations on virialized cluster scales without the necessity of running a large number of simulations.

Preparation and Properties of Zinc Diacrylate-Modified Montmorillonite/Rubber Nanocomposite

Organo-montmorillonite (OMMT)/nature rubber (NR) nanocomposites were prepared by mixing method. The microstructure of these composites was characterized by SEM and XRD. The effect of OMMT on mechanical properties and thermal conductivity of the nanocomposites was investigated in detail. SEM and XRD confirmed the intercalated structure of OMMT/NR nanocomposites. The introduction of a small amount of OMMT greatly improved the mechanical properties and thermal conductivity behavior, which was attributed to the nanometer scale dispersion and stronger interactions between OMMT and NR chains.

Synthesis and Properties of the ESA/AMPS Copolymer

A copolymer was prepared from epoxy succinic acid (ESA) and 2-acrylamido-2-methyl propane sulfonic acid (AMPS). The structure of the ESA/AMPS copolymer was characterized by means of FTIR. The performances of scale inhibition, dispersion and biodegradability of the ESA/AMPS copolymer were studied. The results showed that the scale inhibition performance of the ESA/AMPS copolymer on calcium phosphate and dispersing performance on ferric oxide were much better than PESA. The scale inhibition rate on calcium carbonate was 85% when the ESA/AMPS copolymer was 8mg/L. The scale inhibition rate on calcium phosphate was 65% when the ESA/AMPS copolymer was 30mg/L. The ESA/AMPS copolymer had good biodegradation performance and biodegradation rate could reach 65% after 28 days.

Small scale particulate matter measurements and dispersion modelling in the inner city of Liège, Belgium

In the framework of the Interreg-IV ‘PM-Lab’ project a local-scale exercise was set up to evaluate air pollution in terms of particulate matter (PM) within the centre of Liège, Belgium (pop. 190,000). Sixteen sites distributed on a boulevard and its side streets were selected to determine the spatio-temporal variation of PM concentration in this traffic-dominated area. In addition to the in situ measurements numerical simulations were performed by means of AUSTAL2000. The performance of this Lagrangian dispersion model was checked through some basic qualitative and quantitative comparisons. As the model was able to detect highest PM concentrations both in space and time, test scenarios of emission reductions were also run in order to examine the impact of different traffic related measures.

Assessing the local scale annual air quality impact of industrial source from characteristic days

An approach of assessing the annual air quality impact of industrial sources from results of simulations performed for characteristic days, representative for different local scale dispersion conditions, is being studied. The methodology for selecting the characteristic days is presented. For classifications with different number of similar day clusters the air-quality directive limit and target values for SO 2 are calculated from CALMET/CALPUFF model simulations performed for representative days. These results are compared with target and limit values assessed from results of simulations performed over the entire one year time period. Results show that especially the annual average and hourly maximum fields can be assessed from characteristic days, but it cannot be assured that certain classification with selected characteristic days will provide accurate results.

The Austrian guideline for short scale dispersion modelling

Dispersion modelling during licensing procedures is, due to the limited time frame, a rather challenging task. Complex building structures or source configurations, which call for sophisticated dispersion models require usually long computation times. A new modelling tool for such applications has been developed in Austria, which is based on simulations for 34 pre-defined source configurations using the Lagrangian Particle Model GRAL (Graz Lagrangian Model). Annual mean, maximum daily mean, and maximum hourly concentrations can be calculated within a few seconds/minutes. The model is already approved by the Austrian ministry and is made available free of charge.

Synthesis of polyaspartic acid–melamine grafted copolymer and evaluation of its scale inhibition performance and dispersion capacity for ferric oxide

Polyaspartic acid–melamine grafted copolymer (denoted as PASPM) was synthesized by using polysuccinimide and melamine as the starting materials. Resultant grafted copolymer was characterized by means of Fourier transform infrared spectrometry (FTIR) and NMR. The scale inhibition behavior of PASPM copolymer against CaCO 3 and Ca 3(PO 4) 2 scales was evaluated using static scale inhibition method, and its dispersion capacity for ferric oxide and ability to retard deposition of CaCO 3 were also examined. It was found that PASPM was able to efficiently inhibit deposition of CaCO 3 and had good dispersion ability for Fe 2O 3. The maximum inhibition efficiency, as high as 98.97%, was reached at an inhibitor concentration of 10 mg/L. The best dispersion efficiency for Fe 2O 3 was reached when 34 mg/L of PASPM was introduced into the tested solution, corresponding to 39.1% of light transmittance of the solution.

Scale Reduction and Dispersion of Production Systems (Value Chain): A New Opportunity for Innovation and Entrepreneurship

Managers of established firms as well as emerging firms continually search for unique strategies that ensure better returns with minimal risk, and that enable their businesses to effectively outsmart the competitive challenges by attaining the advantages in terms of innovation, cost efficiency and market responsiveness. While large firms struggle to sustain the innovativeness and market responsiveness as they experience inertia due to size, Whereas the small firms on the growth trajectory search for strategic means to overcome the competitive challenges and explore ways to break the industry barriers. Managers and organizational design experts have been proposing a variety of strategic and organizational solutions to sustain the dynamism and enable the firms to match the competition in terms of new products, lower cost, quality, and customer service. We propose in this paper, how a shoaling (school of fish design) approach will serve as distinctive corporate and business strategy and will benefit the firms to operate in a most nimble and effective way. This unique strategy will enable a large firm operate like a smaller firm as well as offer the small firm(s) many ways to cope with rivalry from larger players. On the one hand, this strategy reduces the opportunity cost of not exploiting the fleeting opportunities, and on the other hand reduces the sunk cost and investment risk by operating as dispersed but in a synchronized manner like the school of fish. We contemplate the economic and managerial rationale of the ‘shoaling strategy or disaggregated and dispersed organization’, and its significance in the context of knowledge economy and turbulence experienced in several markets and industries.

Ground-fixed and on-board measurements of nanoparticles in the wake of a moving vehicle

An integrated experimental methodology has been applied to measure number and size distributions of particles in the 5-560nm size range in the wake of a diesel car running at different speeds. Measurements were made at both ground-fixed (0.10 and 0.25m above the ground level) and on-board (in 12 different sampling locations behind the moving car) measurement configurations using a fast response differential mobility spectrometer (Cambustion DMS50) with a sampling frequency up to 10Hz. Results from both the experimental campaigns were analysed to understand the dynamics, dispersion and transport of nanoparticle emissions in the wake of a moving vehicle. Temporal changes in results were divided into three main stages (pre-evolution, evolution and post-evolution) after the release of exhaust emissions from the tailpipe. Evolution stage is of most interest where all the changes to particle number and size distribution occurred. Up to four evolution sub-stages were observed, each showing distinct evolution patterns of particle size distributions, depending on the particular experimental run. In agreement with previous studies, dilution was found to be the dominant process throughout all the evolution stages. The first evolution sub-stage was common to all the measurements, and consisted of an initial particle number concentrations and distributions change due to rapid (less than 1s) nucleation followed by a rapid increase of accumulation mode particle number concentrations. After this first sub-stage the presence of vehicle wake with recirculating particles and the possible influence of other transformation processes lead to complex interactions. Results from the two experimental datasets clearly confirm the presence of two separate groups of particles: (i) new particles, which are freshly emitted and come directly from the tailpipe and (ii) relatively aged particles, which are entrained within the recirculation vortices of the vehicle wake and reside there for a longer time. The two groups have different characteristics and interact with each other. This interaction has often been overlooked in past studies about local scale dispersion of nanoparticle from moving vehicles.

Synthesis of polyaspartic acid–aminobenzenesulfonic acid grafted copolymer and its scale inhibition performance and dispersion capacity

Polysuccinimide (abridged as PSI) was synthesized by urea and maleic anhydride. Aminobenzenesulfonic acid (ABSA) was introduced at different mole ratio to PSI to generate polyaspartic acid (abridged as PASP)/ABSA graft copolymer. The scale inhibition behavior of resultant PASP/ABSA copolymer was evaluated by using static scale inhibition method. The transmittance of the supernatant of the copolymer solution was measured to evaluate its dispersion ability for ferric oxide. The corrosion inhibition performance of the copolymer for iron plates immersed in the refined testing water (including 0.555 g of CaCl2 2H2O, 0.493 g of MgSO4 7H2O, 50 mg PASP/ABSA graft copolymer and 0.168 g of NaCl) was tested. It was found that PASP/ABSA copolymer was able to efficiently inhibit CaCO3 and Ca3(PO4)2 scales and had good corrosion inhibition ability as well, and it also had good dispersion ability for Fe2O3. Besides, the inhibition efficiency of PASP/ABSA against CaCO3 and Ca3(PO4)2 scales and its dispersion capacity for Fe2O3 was highly dependent on dosage. The reason may lie in that PASP/ABSA copolymer simultaneously possesses carboxylic ion and sulfonic group which can chelate Ca2+ to form stabilized and dissoluble chelates, resulting in increase of solubility of calcium salts in water. Also it may lie in that the introduction of acidic hydrophilic sulfonic group with a strong electrolytic capacity into PASP molecule simultaneously enhances the dispersion of the inhibitor molecules and hinders the formation of Ca3(PO4)2 scale.

Preparation of Zinc Diacrylate-Modified Montmorillonite/Rubber Nanocomposite with High Thermal Properties

Organo-montmorillonite (OMMT)/nature rubber (NR) nanocomposites were prepared by mixing method. The microstructure of these composites was characterized by SEM and XRD. The effect of OMMT on mechanical properties and thermal conductivity of the nanocomposites was investigated in detail. SEM and XRD confirmed the intercalated structure of OMMT/NR nanocomposites. The introduction of a small amount of OMMT greatly improved the mechanical properties and thermal conductivity behavior, which was attributed to the nanometer scale dispersion and stronger interactions between OMMT and NR chains.

Temporal limits to simulating the future spread pattern of invasive species: Buddleja davidii in Europe and New Zealand

The spread of invasive species is a major ecological and economic problem. Dynamic spread modelling is a potentially valuable tool to assist regional and central government authorities to monitor and control invasive species. To date a lack of suitable data has meant that most broad scale dispersal models have not been validated with independent datasets, and so their predictive ability and reliability has remained unscrutinised. A dynamic, stochastic dispersal model of the widely invasive plant Buddleja davidii was calibrated on European spread data and then used to project the temporal progression of B. davidii's distribution in New Zealand, starting from several different historical distributions. To assess the model's performance, we constructed an occupancy map based on the average number of simulation realisations that have a population present. The application of Receiver Operating Characteristic (ROC) curves to occupancy maps is introduced, but with specificity substituted by the proportion of available area used in a realisation. A derivative measure, the partial area under these curves when assessed through time (pAUC), is introduced and used to assess overall performance of the spread model. The model was able to attain a high level of model sensitivity, encompassing all of the known locations within the occupancy envelope. However, attempting to simulate the spread of this invasive species beyond a decade had very low model specificity. This is due to several factors, including the exponential process of spread (the further a population spreads the more sites exist from which it can spread stochastically), and the Markovian chain property of the stochastic system whereby differences between realisations compound through time. These features are seen in many reports of spread models, without being explicitly acknowledged. Our measure of pAUC through time allows a model's temporal performance and its specificity to be simultaneously assessed. While the rapid deterioration in model performance limits the utility of this type of modelling for forecasting long-term broad-scale strategic management of biological invasions, it does not necessarily limit its attractiveness for informing smaller scale and shorter term invasion management activities such as surveillance, containment and local eradication.