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Abstract The present study evaluates the feasibility of applying forward osmosis (FO) process for the pretreatment of feed solution to a Multi Stage Flash (MSF) desalination plant. For the first time, real brine reject and real seawater were used as the draw solution and the feed solution, respectively in the FO process. The FO pretreatment is expected to dilute the brine reject and reduce the concentration of divalent ions, which are responsible for scale formation on the surface of heat exchanger in the MSF evaporator unit. The FO experiments were performed at different draw solution temperatures ranging between 25 and 40 °C, different draw and feed solutions flowrates and different membrane orientations. A maximum average membrane flux of 22.3 L/m2·h was reported at a draw solution temperature of 40 °C and 0.8 and 2.0 LPM flow rate of draw and feed solutions, respectively. The experimental results also revealed the process sensitivity to the feed solution temperature. It was found that the average membrane flux in the FO process operating at 0.8 and 2 LPM draw and feed solution flow rates, respectively was 16.9 L/m2·h at 25 °C brine temperature but increased to 22.3 L/m2·h at 40 °C brine temperature. These membrane fluxes resulted in 3% and 8.5% dilution of the draw solution at 25 °C and 40 °C temperatures, respectively. The average membrane flux in the FO mode was equal to that in the PRO mode at low flow rates but it was lower than that in the PRO mode at high flow rates of the feed and draw solutions. The outcomes of the study are very promising with regard to membrane flux and dilution of draw solution. Highlights • The brine was diluted by 3% and 8.5% when flow rate was changed to 0.8 LPM and 2 LPM respectively. • At low flow rate, membrane orientation had no effect on the flux. • At high flow rate the flux was lower for PRO mode. • At 0.8 LPM flow rate and at 25 °C, the flux was 16.9 L/m2·h. • At 2 LPM flow rate and at 40 °C, the flux was 22.3 L/m2·h. [ABSTRACT FROM AUTHOR]

Abstract One of the major problems of seawater reverse osmosis (SWRO) process is the formation of inorganic scales (calcium carbonate, CaCO 3) and calcium sulfate, CaSO 4)) on the membrane surface, which degrades the filtration performance. Antiscalants have been applied to SWRO plants to overcome the scaling problem. In this study, we used the air micro-nano bubbles (MNBs) as a chemical-free scale inhibition method to improve the overall membrane performance in the comparison with the commercially available antiscalants. During four days of continuous experiments with MNBs, the permeate fluxes declined to 86.5(0.4)% and 83.0(0.5)% with CaCO 3 and CaSO 4 containing feed solutions, respectively. These values were higher than those obtained with the use of antiscalants in the feed water (CaCO 3 –63.5(0.4)% and CaSO 4 –55.8(1.0)%). Membrane fouling characterization results showed that the MNBs efficiently controlled the scaling development on the membrane surface without any chemical addition. Graphical abstract Unlabelled Image Highlights • Air micro-nano bubbles (MNBs) inhibit calcium crystal formation on SWRO membranes. • Continuous MNBs application is effective to improve the SWRO performances. • Scaling inhibition of MNBs is better than antiscalant used in this study. • MNBs helps to achieve a chemical-free SWRO operation. • MNBs can reduce the operational cost and the environmentally negative impacts. [ABSTRACT FROM AUTHOR]

Graphical abstract (a) Electric field amplitude (E 0) dependence of P - E hysteresis loops measured at 0.1 Hz. The inset (b) shows hysteresis area < A > of the hysteresis loops with variation E 0. (c), (d) are the plots of ln P r , ln E c , ln< A > and dln< A >/dln E 0 versus ln E 0. Here, the polarization reversal and dynamic hysteresis were investigated in (Bi 1/2 Na 1/2)TiO 3 (BNT) ceramics. The scaling behaviors were presented by studying the dependence of hysteresis loops on the field amplitude E 0. New feature of polarization responses and scaling behaviors were obtained. The exponent α in an equation of the hysteresis loop area < A >∝ E 0 α displayed large values in high- E 0 stage. Highlights • The exponent α in the hysteresis loop area < A >∝ E 0 α equation shown large values in high- E 0 stage. • The < A > displayed abnormal increase with temperature. • A near frequency-invariant coercive field E C , accompanied by a weakly dependent P r and < A > was observed. Abstract The excellent electrical properties and potential applications of ferroelectric ceramics are intrinsically correlated with the dynamic polarization response under applied electric field. However, the lack of clarity with regard to global polarization reversal process has hindered the understanding of the functional properties. Here, the polarization reversal and dynamic hysteresis were investigated in (Bi 1/2 Na 1/2)TiO 3 (BNT) ceramics. The scaling behaviors were presented by studying the field amplitude E 0 , frequency f 0 and temperature T 0 dependence of hysteresis loops. Three new features of polarization responses and scaling behaviors were obtained. First, the exponent α in the hysteresis loop area < A >∝ E 0 α equation displayed large values in high- E 0 stage. Then, the < A > displayed an abnormal increase with increasing temperature. Finally, a near frequency-invariant coercive field E C , accompanied by a weak dependent P r and < A >, was observed. The correlation between these new features and polarization extension/rotation as well as complex domain structure and field-induced phase transition was demonstrated. [ABSTRACT FROM AUTHOR]

One of the major challenges in membrane distillation (MD) desalination is scaling, mainly CaSO 4 and CaCO 3 . In this study, in order to achieve a better understanding and establish a strategy for controlling scaling, a detailed investigation on the MD scaling was performed by using various analytical methods, especially an in-situ monitoring technique using an optical coherence tomography (OCT) to observe the cross-sectional view on the membrane surface during operation. Different concentrations of CaSO 4 , CaCO 3 , as well as NaCl were tested separately and in different mixed feed solutions. Results showed that when CaSO 4 alone was employed in the feed solution, the mean permeate flux (MPF) has significantly dropped at lower volume concentration factor (VCF) compared to other feed solutions and this critical point was observed to be influenced by the solubility changes of CaSO 4 resulting from the various inlet feed temperatures. Although the inlet feed and permeate flow rates could contribute to the initial MPF value, the VCF, which showed a sharp MPF decline, was not affected. It was clearly observed that the scaling on the membrane surface due to crystal growth in the bulk and the deposition of aggregated crystals on the membrane surface abruptly appeared close to the critical point of VCF by using OCT observation in a real time. On the other hand, NaCl + CaSO 4 mixed feed solution resulted in a linear MPF decline as VCF increases and delayed the critical point to higher VCF values. In addition, CaCO 3 alone in feed solution did not affect the scaling, however, when CaSO 4 was added to CaCO 3 , the initial MPF decline and VCF met the critical point earlier. In summary, calcium scaling crystal formed at different conditions influenced the filtration dynamics and MD performances. [ABSTRACT FROM AUTHOR]

The application of reverse osmosis (RO) membrane in wastewater reclamation is emerged as a potential technology. As far as the operational conditions are concerned, inorganic fouling is a major challenge for membrane treatment systems. At present various antiscalants and chemicals are commercially available for scale inhibition on the surface of membrane. In an earlier study we found that CO 2 can effectively inhibit scale growth on the surface of RO membrane in wastewater reclamation. On the basis of previous study, the scale inhibiting efficiency of CO 2 was compared with three commercially available antiscalants. The RO system was operated at constant applied pressure with four different scale inhibition methods including CO 2 , Flocon 260, Flocon 300 and Kuriverter N-500. The permeate flux decline was considered as an indication of scale growth on the membrane surface. The percent salt rejection and ionic mass balance was used to determine the scaling behavior of the RO modules. Membrane autopsy was done to determine the effect of CO 2 and antiscalants on the membrane structure. The experimental data revealed that CO 2 can effectively inhibit scale growth as compared with all of three antiscalants. However, the Flocon 260 was found better than other two antiscalants. [ABSTRACT FROM AUTHOR]

Scaling effects in the perforation resistance of a carbon fibre-reinforced polymer (CFRP) composite have been investigated under quasi-static and low velocity impact loading conditions. The perforation data have been supplemented with results from additional flexural tests on scaled composite beams, which highlighted a decrease in both strength and failure strain as scale size increases. Strain-rate effects in this composite have been also identified, with the plates absorbing less energy as the loading-rate is increased. Tests on scaled plates have shown that the normalised perforation energy increases rapidly with scale size. An examination of the load-displacement response indicates that the elastic response obeys a simple scaling law, whereas that the damage does not. It was found that fibre damage was more severe in larger composite panels. It is argued that the energy absorbed in fibre fracture does not scale in the expected manner, leading to greater levels of fibre damage in the larger plates. [ABSTRACT FROM AUTHOR]

The performance of pressure retarded osmosis (PRO) processes is significantly limited by membrane fouling. This study systematically investigated PRO scaling by silica, which is one of the most common salts causing membrane scaling. In particular, the effect of silica concentration, the initial water flux, the chemistry of feed solution (FS) /draw solution (DS), and the type of membrane were studied in the PRO mode of operation. It has been observed that a low silica concentration (e.g., 10 mg/L SiO 2 ) could even cause membrane scaling during a PRO process. The rate and extent of the scaling was mainly governed by the internal concentration of silica in the membrane support layer and the solution chemistry of the FS/DS. The results suggested that the scaling could be mitigated by decreasing the internal concentration through the reduction of bulk silica concentration, the optimization of operating water flux, and the decrease in membrane structural parameter. The structural parameter seems to play a dominant role in PRO scaling by silica than the membrane materials and other physico-chemical properties. In addition, silica scaling can be controlled by lowering the pH of the FS and/or DS. For the first time, it has been demonstrated that utilizing an acidic DS was highly effective in controlling PRO scaling, which can be attributed to the low local pH in the membrane support layer as a result of the internal concentration polarization (ICP) of the reversely diffused H + . This method opens a new dimension for PRO scaling/fouling control. [ABSTRACT FROM AUTHOR]

A chemical separation technique for removing interfering gamma-ray radionuclides by combined precipitation of Nb pentoxide and anion exchange was proposed, thereby allowing detection of trace 94 Nb in low-level radwastes. The detection limit for 94 Nb was improved by a factor of 10–10 3 , and the scaling factor ( 94 Nb/ 60 Co) of the radwastes was estimated to be less than 10 −5 . This technique can be used for low-level radwaste classification and power reactor decommissioning. [ABSTRACT FROM AUTHOR]

Experimental results are reported on the effect of polysaccharides in the early stage of membrane scaling. Sodium alginate at small concentration (2 and 10 mg/L) was employed as typical polysaccharide. Synthetic solutions, characterized by small bulk supersaturation ratio S in calcium sulfate (S ~ 1.4), were filtered through a desalination membrane in dead-end cells under agitation. Three types of tests were performed; i.e. membrane scaling in absence of alginates (as reference), combined fouling-scaling (i.e. scaling in presence of alginates) and scaling tests after a fouling layer was formed on the membrane. Examination of various deposits by Scanning Electron Microscopy (SEM) and determination of calcium on membrane deposits and in filtered solids (from retentate and feed-fluid samples) provide useful insights including clear evidence that alginates tend to inhibit CaSO 4 crystallization, likely due to calcium binding with carboxylates of alginate macromolecules and formation of gel deposits. The inhibition effect, manifested in the reduced deposit-mass density on membranes and crystallization–rate, as well as in crystal-shape modification, is stronger at the higher alginate concentration. Similarly, incipient membrane scaling, pretreated with alginate foulant solution, appears to be significantly inhibited compared to clean membranes. Under the conditions tested, membrane salt rejection was unaffected. [ABSTRACT FROM AUTHOR]

Purpose High silicon amorphous steels are gaining preference as the material of choice for the fabrication of the core of low and medium power electrical transformers because they present a better electromagnetic behaviour compared to that offered by common grain-oriented and non-oriented high silicon steels. This study aims to investigate the effects that the environmental conditions present during the high temperature annealing of cores exert on the surface oxidation and electromagnetic changes experienced by a commercial amorphous steel alloy.Design/methodology/approach The effect of environmental impact on the correct development of annealing practices during the manufacture process of amorphous steel cores used in distribution transformers was studied by the development of an oxidation reactor. With this installation, it was possible to simulate environmental conditions that could affect the surface of magnetic cores made from amorphous steel.Findings It was found that: the surface oxidation of amorphous steels affects their electromagnetic behaviour, environmentally induced surface degradation can be modelled at laboratory scale and oxide formation does not affect the amorphous condition of the alloy.Originality/value The effect of surface oxidation induced by the existence of water vapour in the annealing process of cores made from amorphous steels and its impact on the electromagnetic behavior of these alloys has been barely studied. [ABSTRACT FROM AUTHOR]

Background: Mineral precipitates (scaling) from deep saline thermal waters often constitute a major problem during geothermal energy production. The occurrence of scale-fragments accumulating and clogging pipes, filters, and heat exchangers is of particular concern regarding an efficient energy extraction. Methods: Carbonate scale-fragments from different sections of two geothermal power plants were collected and studied in a high-resolution scaling forensic approach comprising of microstructural characterization, elemental mapping, and stable carbon and oxygen isotope transects. The solid-phase analyses were evaluated in the context of natural environmental and technical (man-made) production conditions. Results and discussion: Our results indicate an interaction of metal sulfide mineral layers mainly from HS corrosion of the steel pipes and CaCO nucleation and crystal growth. A conceptual model of scale-fragment development addresses the relevance of two key interfaces: 1) the corrosion layer between the steel substrate and calcite scale and 2) the scale surface versus thermal fluid flow. The corrosion products constitute an attractive crystallization substrate of brittle and mechanically weak consistency. A rough carbonate scale surface tends to induce (micro) turbulences and increased flow resistance (frictional forces). These factors promote partial exfoliation, scale-fragment mobilization, and rapid clogging. This investigation highlights the potential of detailed petrographic and geochemical analyses of mineral precipitates for evaluating favorable versus unfavorable processes in geotechnical environmental settings. [ABSTRACT FROM AUTHOR]

Silicate scaling is often induced by alkaline surfactant polymer (ASP) flooding in sandstone reservoirs. The formation of silicate scale is complicated by its dependence on multiple factors including pH, silica concentration, and magnesium concentration, which vary as the flood progresses. These factors affect silicate scaling tendency, and consequently, severity of the problem. Silicate scale is a very serious problem in the oil and gas production system. Therefore, silicate scale inhibitors have been suggested to mitigate problems in oilfields. In this study, some of the dendrimers inhibitors with enhanced functionality used in the water industry were reviewed and assessed for possible application in oilfields scales. It was found that the NH 2 -terminated dendrimers exhibited excellent inhibitory silica polymerization efficiency compared with the control. It is now certain that effective silica scale inhibition is dependent on the cationic charge on the polymer backbone. However, these dendrimer inhibitors suffered from a serious disadvantage when the silicates that had not been inhibited entrapped the dendrimers. Visual observations showed that these particles appeared as white flocculant precipitates at the bottom of the test vessels. Previously, it had been found that silica scale inhibition could be achieved by using of scale inhibitors in combination with anionic polymer additives. It is believed that an effective silica inhibition should be based on a delicate balance structure of cationic–anionic charges. Therefore, in the present study pteroyl-L-glutamic acid (PGLU) compound is used in synergistic action with cationic dendrimer polymer. PGLU was proven to be an effective scale inhibitor at high temperature in aqueous solution of synthetic produced water. Furthermore, it was found that PGLU assisted the inhibitory action of dendrimers by alleviating formation of insoluble SiO 2 -PAMAM precipitates to operate more effectively. [ABSTRACT FROM AUTHOR]

The role of gas stirring in ladle metallurgy has been well appreciated and a great volume of pertaining studies have been carried out, mostly resorting to numerical modeling and/or physical modeling. As for physical modeling of gas-liquid flow in metallurgical ladles, a (conventional) scaling equation, i.e. [ABSTRACT FROM AUTHOR]

The influence of the reagent KISK-1 (Russia) on the rate of corrosion of Steel 3 in mineralized (“hard”) waters of two industrial plants was studied. The water supply system of the two plants used in the study had sufficient difference in chemical composition. Thermostability of these waters was investigated in the presence of KISK-1 (the complex inhibitor of scaling and corrosion). It was shown that when used at correct dosage, KISK-1 is capable of significantly reducing the rate of corrosion of Steel 3 while also providing the water system’s thermostability in evaporation, i.e. preventing the formation of sediments and deposits of salts. It was shown that the optimum dosage of KISK-1 remains relatively stable, while the tested waters were evaporated by 1.7–2.5 times. At the same time, the existence of some threshold concentration, above which the increase in the concentration of KISK-1 does not produce a proportional decrease in the rate of corrosion of Steel 3 was established. The approach offered in this study provides a useful framework to conduct comparative analysis and choose suitable reagents for the prevention of scaling and corrosion in water supply systems in a variety of industrial plants. [ABSTRACT FROM PUBLISHER]

Water quality entering the drinking water distribution network often provides requirements for corrosion and scaling in rural areas due to the lack of suitable treatment methods. It leads to pipe clogging, reducing longevity of the equipment, and health problems caused by dissolved compounds in the water. The present study aims to evaluate the corrosion and scaling potential in water distribution networks of four villages located in different geographical locations of Urmia, Iran. In this descriptive cross-sectional study, 36 samples of water entering the villages of Dizaj-e Siavosh, Dolama, Gogtapeh, and Band distribution networks were analyzed according to standard methods for water and wastewater examinations. The corrosion and scaling potential were evaluated based on Ryznar stability (RSI), Langelier saturation (LSI), Puckorius scaling (PSI), and Larson–Skold (LRI) indices after determination of pH, total dissolved solids, sulfate, alkalinity, calcium hardness, and chloride. The results indicated that the values of LSI, RSI, PSI, and LRI indices were −1.94, 12.05, 12.20, and 0.68 for Gogtapeh water supply; −2.22, 12.72, 13.6, and 0.4 for Dizaj-e Siavosh water supply; −2.03, 12.1, 12.06, and 0.3 for Band water supply; and finally −2.09, 12.30, 12.59, and 0.29 for Dolama water supply, respectivly. Therefore, the water entering Gogtapeh distribution system has a tendency to scaling based on the LRI as an only appropriate index for the corrosion and scaling potential in this village. However, the water entering Dizaj-e Siavosh, Dolama, and Band distribution networks are highly corrosive based on the LSI, RSI, and PSI indices. The concordance between the analysis of chemical water quality and national standards could not be sufficient to confirm the water quality balance in terms of corrosion and scaling potential. [ABSTRACT FROM PUBLISHER]

Scaling of the MOSFET faces greater challenge because of extreme power density due to leakage current in ultra-deep sub-micron (UDSM) technology. To overcome this situation double gate device such as FinFET is used which has excellent control over the thin silicon fins with two electrically coupled gates that mitigate shorter channel effect and exponentially reduce leakage current. The present work utilized the property of FinFET in domino logic, for high speed operation and reduction of power consumption in wide fan-in OR gate. The proposed circuit is simulated in FinFET technology by BISM4 model using HSPICE and 32nm process technology at 25 °C with CL =1 pF and 100 MHz frequency. For 8 and 16 input OR gate in SG mode, we saved an average power of 11.5 % and 11.39 % in SFLD, 22.97 % and 18.12 % in HSD, 30.90 % and 34.57 % in CKD, respectively; while for that in LP mode, we saved an average power of 11.26 % and 15.78 % in SFLD, 19.74 % and 17.94 % in HSD, 45.23 % and 34.69 % in CKD respectively. [ABSTRACT FROM AUTHOR]

The statistical effects of different conditions in physical vapor deposition, such as sputter deposition, have on thin film morphology has long been the subject of interest. One notable effect is that of column development due to differential chamber pressure in the well-known empirical model called the Thornton's Structure Zone Model. The model is qualitative in nature and theoretical understanding with quantitative predictions of the morphology is still lacking due, in part, to the absence of a quantitative description of the incident flux distribution on the growth front. In this work, we propose an incident Gaussian flux model developed from a series of binary hard-sphere collisions and simulate its effects using Monte Carlo methods and a solid-on-solid growth scheme. We also propose an approximate cosine-power distribution for faster Monte Carlo sampling. With this model, it is observed that higher chamber pressures widen the average deposition angle, and similarly increase the growth of column diameters (or lateral correlation length) and the column-to-column separation (film surface wavelength). We treat both the column diameter and the surface wavelength as power laws. It is seen that both the column diameter exponent and the wavelength exponent are very sensitive to changes in pressure for low pressures (0.13 Pa to 0.80 Pa); meanwhile, both exponents saturate for higher pressures (0.80 Pa to 6.7 Pa) around a value of 0.6. These predictions will serve as guides to future experiments for quantitative description of the film morphology under a wide range of vapor pressure. [ABSTRACT FROM AUTHOR]

Assessing the vulnerability of biological communities to anthropic pressures in marine systems may be challenging because of the difficulty to properly model each species' response to the pressure due to lack of information. One solution is to apply factor-mediated vulnerability assessment which combines (i) information on species ecological traits and conservation status organized in a matrix of so-called "vulnerability factors", (ii) a conceptual model of how these factors affect species vulnerability, and (iii) data on the spatial distribution and abundance of each species issued from at-sea surveys. Such factor-mediated vulnerability assessment was originally introduced in the seabird-wind farm context by Garthe and Hüppop (2004. Scaling possible adverse effects of marine wind farms on seabirds: developing and applying a vulnerability index. Journal of Applied Ecology, 41: 724-734) and has since then been expanded to many case studies. However, the mathematical formulations that were proposed at that time are overly simplistic and may overlook critical components of the impact assessment. Our study briefly reviews the original approach and highlights its hidden assumptions and associated interpretation problems, for example, the overestimation of disturbance pressure to the detriment of collision, or the very high contribution of log abundances in vulnerability maps. Then, we propose a revised framework that solves these issues and permits easy transposition to other community-pressure case studies. To illustrate the usefulness and generality of the revised framework, we apply it to two case studies, one concerning the vulnerability assessment of a seabird community to offshore wind farms in the Bay of Biscay, and another focusing on the vulnerability assessment of the benthic megafauna community to trawling pressure in the Barents Sea. [ABSTRACT FROM AUTHOR]

A study of the temperature (T) and density (ns) dependence of conductivity σ(ns,T) of a highly disordered, two-dimensional (2D) electron system in Si demonstrates scaling behavior consistent with the existence of a metal-insulator transition (MIT). The same critical exponents are found when the Coulomb interaction is screened by the metallic gate and when it is unscreened or long range. The results strongly suggest the existence of a disorder-dominated 2D MIT, which is not directly affected by the range of the Coulomb interactions. [ABSTRACT FROM AUTHOR]

This study reports on experimental investigations on the prosodic patterns of restrictive and appositive relative clauses (RRCs and ARCs) in German. RRCs and ARCs are associated with distinct prosodic patterns: While RRCs involve prosodic integration with their antecedent and may involve an accent shift from the antecedent to the determiner, ARCs are prosodically separated from their host clause. In the framework of two production experiments and one perception experiment, RRC and ARC constructions were tested in regard to F0 scaling, segment duration, silent pauses, and accent placement under different conditions. The results support the intuitive prosodic patterns described in the literature: ARC constructions were realized with higher F0 scaling and longer word duration preceding the relative clause, which indicates the presence of a prosodic phrase boundary, and accentuation of the determiner occurred only with RRC constructions. In perception, silent pauses were taken as cues to ARCs and accent shift as a cue to RRCs. These results suggest a difference in prosodic phrase structure reflecting the different syntactic structures. However, the production experiments also revealed that the prosodic differences are absent when the communicative situation does not require the disambiguation of the relative clause types. [ABSTRACT FROM AUTHOR]

On the benefit of the concept of the so-called diluted magnetic oxides, Fex(ZnO)1-x (x = 0.50-0.85) granular thin films with different thickness through 2D and 3D percolation region were prepared by ion beam assisted deposition. All samples are ferromagnetic at room-temperature due to the ferromagnetic nature of the Fe-doped ZnO matrix, which is quite different from the superparamagnetic behavior in the insulator-matrix based granular films. Along with decreasing thickness, the Hall coefficient RS is largely enhanced. The maximum RS reaches 4.27 x 10-7m³/C in ~2.8nm Fe0.6(ZnO)0.4 granular film, which is nearly 9 times larger than the RS (4.64 x 10-8m³/C) of the ~50nm Fe0.6(ZnO)0.4 sample. Meanwhile, the RS could maintain in a wide temperature region from 10K to 300K and the Hall sensitivity reaches ~130V/AT at room-temperature. The scaling exponential of n = 1.7 ± 0.1 in σxy ~ σnxx is observed, fitting well with the recent developed universal scaling theory characterized by n = 1.6 in the dirty limit. [ABSTRACT FROM AUTHOR]

Scaling is a major obstacle in harnessing of geothermal energy from the geothermal resources. This paper presents a case study for inhibition of metal silicate scaling using formic acid, harvesting more energy in particular case of Tuzla Geothermal Field (TGF), located on Biga Peninsula, in the northwestern of Turkey. TGF is 5 km far from Aegean Sea and 80 km south of Çanakkale. Geothermal fluid of TGF has high salinity (EC > 91 mS/cm) and medium temperature (reservoir temperature is 173 °C). The acidification of high-salinity brine to mitigate silicate scaling is examined. Results of the study showed that a compromise between scaling and corrosion is achieved by reducing pH of brine to <6 using 55 ppm formic acid. [ABSTRACT FROM AUTHOR]

Abstract: The use of redox potential measurements for corrosion and scaling monitoring, including microbially mediated processes, is demonstrated. As a case study, monitoring data from 10years of operation of an aquifer thermal energy storage (ATES) site located in Berlin, Germany, were examined. (Fe2+)-activities as well as [Fe3+]-build up rates were calculated from redox potential, pH, conductivity, temperature and dissolved oxygen measurements. Calculations are based on assuming (Fe3+)-activity being controlled by Fe(OH)3-solubility, the primary iron(III)-precipitate. This approach was tested using a simple log-linear model including dissolved oxygen besides major Fe2+-ligands. Measured redox potential values in groundwater used for thermal storage are met within ±8mV. In other systems comprising natural groundwater and in heating and cooling systems in buildings, quantitatively interpretable values are obtained also. It was possible to calculate particulate [Fe3+]-loads in the storage fluids in the order of 2μM and correlate a decrease in filter lifetimes to [Fe3+]-build up rates, although observations show clear signs of microbially mediated scaling processes involving iron and sulphur cycling. [Copyright &y& Elsevier]

Highlights: [•] Feed and permeate velocities influenced DCMD performance and scaling development. [•] Suitable velocity combination enhanced recovery ratio with reduced pumping energy. [•] Surface crystallisation was reduced with suitable velocity combination. [Copyright &y& Elsevier]

Abstract: Pressure retarded osmosis (PRO) is an osmotically-driven membrane process that can be used to harvest salinity-gradient power. The PRO performance (both water flux and power density) can be severely limited by membrane fouling. The current study, for the first time, investigates PRO scaling in a bench-scale pressurized system using calcium sulfate dihydrate (gypsum) as a model scalant. In addition to the bulk feed solution (FS) saturation index (SIbulk), gypsum scaling was found to be strongly affected by the draw solution (DS) type and concentration, the applied hydraulic pressure, and the membrane orientation. The commonly recommended active layer facing draw solution (AL-DS) orientation was highly prone to internal scaling. In this orientation, severe internal concentration polarization (ICP) of scaling precursors induced gypsum clogging in membrane support layer even when the FS was undersaturated (e.g., SIbulk = 0.8). At higher SIbulk values, external gypsum crystal deposition occurred in addition to internal scaling. More severe scaling was observed when the DS contained scaling precursors such as Ca2+ or , suggesting that the reverse diffusion of these precursors into the FS can significantly enhanced gypsum scaling. Increasing applied hydraulic pressure could enhance reverse solute diffusion and thus result in more severe gypsum scaling when the DS contained scaling precursors. A conceptual model, capturing the two important PRO scaling mechanisms (ICP of scaling precursors from FS and reverse diffusion of scaling precursors from the DS), is presented to rationalize the experimental results. Our results provide significant implications for PRO scaling control. [Copyright &y& Elsevier]

Modeling the operation of spiral-wound membrane modules is essential for their successful design and optimization. Such models must include the main types of membrane fouling, degrading desalination plant performance, including scaling due to sparingly soluble salts. Unfortunately, the complexity of underlying physicochemical processes and the coexistence of several spatial and temporal scales render intractable modeling of membrane scaling based on first principles. Therefore, a suitable (albeit simplified) framework is developed for incorporating scaling dynamics into a fluid flow model formulated at an intermediate (i.e., mesoscopic) length scale of membrane operation. The general mesoscopic approach involves integration of spatially distributed submodels, thereby allowing predictions at the large (entire membrane sheet) scale; these submodels comprise constitutive laws and kinetic rate expressions derived at fine scales. A submodel for the effect of pre-existing bulk particles on scale formation is developed herein. Several numerical results are presented to exemplify the potential of the proposed framework. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2917-2927, 2013 [ABSTRACT FROM AUTHOR]

We consider the exclusion process in the one-dimensional discrete torus with N points, where all the bonds have conductance one, except a finite number of slow bonds, with conductance N-β with β ε [0, ∞). We prove that the time evolution of the empirical density of particles, in the diffusive scaling, has a distinct behavior according to the range of the parameter β. If β ε [0, 1), the hydrodynamic limit is given by the usual heat equation. If β = 1, it is given by a parabolic equation involving an operator ... where W is the Lebesgue measure on the torus plus the sum of the Dirac measure supported on each macroscopic point related to the slow bond. If β ε (1, ∞), it is given by the heat equation with Neumann's boundary conditions, meaning no passage through the slow bonds in the continuum. [ABSTRACT FROM AUTHOR]

Seawater contains high concentrations of sparingly soluble salts which can cause scaling of membrane surface, limiting the productivity and water recovery of seawater reverse osmosis (SWRO). Nanofiltration (NF) pretreatment of seawater, prevents scaling via preferential removal of scale-forming ions. Several studies have shown that the rejection of scale-forming ions is not the same for various membranes. In a previous study, a selection of the best NF membranes for scaling prevention in SWRO was developed using synthetic seawater. The main objective of this study is to test the same NF membranes using real seawater in order to compare the membrane performance using synthetic and real seawater. The seawater used in this study was collected in El Prat de Llobregat (Barcelona). The results obtained showed that the monovalent ions are less rejected in real seawater than in synthetic seawater. However, the rejection of scale forming ions has been practically the same for all membranes in both types of seawater, obtaining a sulphate rejection higher than 90% for the majority of membranes studied, which is highly important for scaling prevention. [ABSTRACT FROM AUTHOR]

Irreversible membrane scaling caused by silica remains a severe problem in many reverse osmosis plants. The engineering task is to find out the appropriate anti-scalant agent and its optimal dosage. Because suitable test methods are missing, a new membrane-based test method was developed. The fully automatically controlled test set-up and the test procedure are described. The effectiveness of 13 anti-scalants for silica was measured at different pHvalues between 7.6 and 9.0 and with silica concentrations from 120 to 275 mg/L. The results show that two of the anti-scalants investigated in this paper have a significant anti-scaling effect for silica. Confocal Laser Scanning Microscope data indicate that even a very thin layer of some 10th of a micrometre can cause heavy scaling on the membrane. [ABSTRACT FROM AUTHOR]

Use of reverse osmosis for treatment of water with high scaling potential was investigated in this study. Treated water comes from a disposal site of ash and desulfurization products and its saturation index of calcium sulfate dihydrate (gypsum) ~0.94. Among other components of the leachate are other dissolved solids (~800 mg/L) with significant content of iron ions (~2.7 mg/L). A series of experiments were performed to study the gypsum bulk crystallization in the presence of antiscalant and iron ions followed by pilot plant testing at the locality with raw leachate and leachate pretreated by coagulation/flocculation to investigate membrane scaling. The results showed that the presence of iron ions significantly reduced the induction time of gypsum crystallization, thereby reducing antiscalant effectiveness for its crystallization suppression. Severe membrane scaling confirmed by permeate flux measurement and pressure drop measurement was found, when raw leachate was treated. Removal of most of iron by pretreatment caused that no undesirable precipitation of solution components and an abrupt decrease in permeate flux was detected during separation process. Average rejection of total dissolved solids was 99.5% in this case. Produced permeate could be reuse as source water for the power plant, thus 80% of wastewater could be recycled by means of reverse osmosis. [ABSTRACT FROM AUTHOR]

This work deals with the optimization, in reverse osmosis desalination plants, of the scheduling of membrane cleanings and rotation of the membrane modules inside each pressure vessel. Each pressure vessel consists of several membrane modules (typically around seven) in series. The modules closer to the feed inlet are prone to be damaged by biofouling and solids, while the modules closer to the reject outlet are prone to be damaged by scaling due to increased salt concentration. Besides, the permeate flux varies for different modules along the pressure vessel. In order to increase the life of the membrane modules, it is a good practice to rotate the modules, thus spreading the difference effects in each module. The topic of this work is to suggest a way to calculate the number and time instants for the rotations, and the optimal operation scheduling. This depends on several factors, such as the time instant for cleanings, the percentage of replacements, the quality of the feed water, etc. Due to the structure of the problem, the calculation is proposed to be done using genetic algorithms or Monte Carlo optimization. [ABSTRACT FROM AUTHOR]

In the present study, the convective flow and heat transfer of an incompressible viscous nanofluid past a semi-infinite vertical stretching sheet in the presence of a magnetic field are investigated. The governing partial differential equations with the auxiliary conditions are reduced to ordinary differential equations with the appropriate corresponding conditions via scaling transformations. The semi-analytical solutions of the resulting ordinary differential equations are obtained using differential transformation method coupled with Pade approximation. Comparison with published results is presented which reveals that the applied method is sufficiently accurate for engineering applications. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigated silica and silicate precipitation as limiting factors in high-recovery membrane operations. For this purpose a cation exchange pretreatment is proposed to reduce Ca2+, Ba2+, Mg2+ levels to prevent scaling of salts containing these ions during subsequent NF and RO filtration, in which RO is fed with NF concentrate. In a pilot plant experiments were carried out at total (NF+RO) water recovery of 91, 94, 96 and 98% with locally available tap water which contains 20mg/L of silica as feed water. Autopsy studies were performed with the RO membranes after each experiment in which the fouling layer was studied using SEM–EDX to determine the structure and the composition of the fouling deposits. A thin cake layer was observed which covered approximately half of the membrane surface after operating for 20 days at 91 and 94% recovery. At 96 and 98% recovery the fouling layer was thicker and completely covered the membrane surface. EDX analysis indicated that the fouling layer was mainly composed of Si, Al, Fe and O, most likely due to the presence of iron oxides, iron hydroxides, silica and aluminosilicates. To be able to work at these high recoveries for an extended period, further measures need to be taken to prevent silica and aluminosilicate scaling. [Copyright &y& Elsevier]

Abstract: The Ho2CoZrO6 (HCZ) double perovskite has been prepared in polycrystalline form by solid state reaction technique. The analysis of the X-ray powder diffraction pattern indicates that the crystal structure is monoclinic at room temperature with cell parameters a =8.1858±0.0023Å, b =5.2599±0.0027Å, c =7.9874±0.0031Å and β =108.51±0.021°. The compound shows significant frequency dispersion in its dielectric properties. The Cole–Cole model is used to determine the polydispersive nature of dielectric relaxation. The scaling behaviour of dielectric loss and imaginary electric modulus suggest that the relaxation describe same mechanism at various temperatures. Impedance data presented in the Nyquist plot (Z″ versus Z′) are used to identify an equivalent circuit and to know the bulk and interface contributions. The complex impedance analysis of HCZ exhibits the appearance of both the grain and the grain-boundary contribution. The frequency dependent conductivity spectra follow the universal power law. The magnitude of the activation energy indicates that the carrier transport is due to the hopping conduction. [Copyright &y& Elsevier]

Seawater desalination is currently considered a vital and dependable water resource to meet all requirements of fresh water. Kuwait has been a leading country in fresh water production from the sea using the multistage flash (MSF) unit. All MSF plants in Kuwait are operated on the principle of chemical additives dosing for scale inhibition, and at a top brine temperature below 120°C. This is because calcium sulfate scaling phenomenon usually occurs when the temperature is higher than 120°C. This type of scaling is a hard scale that cannot be removed easily by chemical or mechanical cleaning. Until recent years, no antiscalants could overcome this type of scaling at high temperatures. The new generation of antiscalants is able to stand high operation temperature without hydrolysis or without losing their reactivity and can solve sulfate scaling problem. This paper consists of laboratory tests to evaluate the performance of new inhibitors that can overcome sulfate scaling. In particular, experiments were conducted to study the antiscalants effectiveness under different operating conditions with different brine concentration, especially in high-temperature operation mode. The result of the experiment showed that the performance of these chemical additives varied with the operating temperature, flow rate, and the brine concentration. The tested chemicals showed reduction in the percentage precipitation at high temperature up to 160°C. A techno-economic feasibility study was also conducted. [ABSTRACT FROM AUTHOR]

Liquid ethanol (C2H5OH) was used to generate a spray of sub-micron droplets. Sprays with different nozzle geometries have been tested and characterised using Mie scattering to find scaling properties and to generate droplets with different diameters within the spray. Nozzles having throat diameters of 470 μm and 560 μm showed generation of ethanol spray with droplet diameters of (180 ± 10) nm and (140 ± 10) nm, respectively. These investigations were motivated by the observation of copious negative ions from these target systems, e.g., negative oxygen and carbon ions measured from water and ethanol sprays irradiated with ultra-intense (5 × 1019 W/cm2), ultra short (40 fs) laser pulses. It is shown that the droplet diameter and the average atomic density of the spray have a significant effect on the numbers and energies of accelerated ions, both positive and negative. These targets open new possibilities for the creation of efficient and compact sources of different negative ion species. [ABSTRACT FROM AUTHOR]

A systematic technique has been developed to determineantiscalingefficiency and dissolution capacity for calcium carbonate in oilfieldbrines under various ultrasonic treating conditions. During the staticexperiments, effects of ultrasonic frequency, acoustic intensity,treating time, and water level on the antiscaling efficiency havebeen evaluated, while the underlying antiscaling mechanism is identifiedand determined. Physically, the formation of calcium carbonate ispromoted as a result of the decreased molecular force and acceleratedmovement of salty ions under ultrasonic irradiation. Most of the formedscale is found to loosely suspend in the liquid, rather than tightlyadhere to the solid surface. During the dynamic experiments, orthogonaltests have been designed to examine effects of interval time, treatingtime, and flow velocity on antiscaling efficiency. As for the dissolutionexperiment, dissolution capacity is measured to evaluate the effectof ultrasonic frequency on dissolution of the formed calcium carbonate.The antiscaling efficiency is found to achieve its maximum value of81.1%, using the ultrasonic treatment with a frequency of 28 kHz,an acoustic intensity of 0.61 W/cm2, an interval time of2 h, a treatment time of 15 min, and a flow velocity of 1.8 m/s. Itis also found that dissolution capacity does not impose a dominanteffect on scale prevention and that the highest dissolution capacityof 19.3% is obtained with an ultrasonic frequency of 28 kHz. [ABSTRACT FROM AUTHOR]

Abstract: Continuous scaling of transistor feature size rapidly increases the effect of intermittent faults. These faults manifest as timing violations due to the combined effects of process variation, circuit wear-out, and variation in environmental conditions. In this paper, we combine all critical sources of intermittent faults in a comprehensive framework. Our experiments with the MIPS-789 processor reveal that at the 22nm technology node, the combined effect of all the factors can degrade the delay by 2.5X. Such gross delay degradation extending more than two cycles can render many recently proposed time borrowing techniques ineffective. We analyze three architectural techniques to mitigate intermittent faults and evaluate them using full system architectural simulation. [Copyright &y& Elsevier]

This study was conducted to investigate the applicability of pulsed electric field (PEF) treatment for the prevention of scaling formation and membrane fouling reduction as the pretreatment of reverse osmosis desalination. To validate the effect of the PEF and to identify the mechanism, a series of experiments with and without the PEF treatment were carried out. All the precipitated crystals in solution were calcite and there were slight differences between with and without the PEF by X-ray diffraction analysis. A rapid particle growth was observed in the case of the PEF treatment. Permeate volume and permeation flux were higher than those without the PEF case. The new PEF method presents an effective tool to mitigate CaCO3 fouling as a pretreatment of membrane filtration. [ABSTRACT FROM AUTHOR]

Higher gas densities and lower diffusion losses at higher operating pressures typically lead to increased charged species densities (and hence flux) for a constant power deposition in capacitively coupled plasmas (CCP). As a result, one would expect that the bias radio-frequency (rf) voltage required to deposit a given power in a CCP reactor decreases with increasing operating pressure. These observations may not hold true in multiple frequency CCPs, commonly used for dielectric etching in microelectronics fabrication, due to nonlinear interactions between the rf sources. Wafer-based measurements of the rf and self-generated direct current (dc) bias voltages in a dual-frequency capacitively coupled electronegative plasma were made, which indicate that the rf and dc voltages vary nonmonotonically with pressure. These experimental results are presented in this paper and a computational plasma model is used to explain the experimental observations for varying 60 MHz and 13 MHz powers in the Ar/CF4/CHF3 plasma over a pressure range of 25 to 400 mTorr. The authors found that while the ion density increases with pressure, the increase is most dominant near the electrode with the high frequency source (60 MHz). The rf and dc bias voltages are ultimately influenced by both charged species density magnitudes and spatial profiles. [ABSTRACT FROM AUTHOR]

Engineering structures such as aircraft, bridges, dams, nuclear containments and ships, as well as computer circuits, chips and MEMS, should be designed for failure probability < 10-10 per lifetime. The safety factors required to ensure it are still determined empirically, even though they represent much larger and much more uncertain corrections to deterministic calculations than do the typical errors of modern computer analysis of structures. The empirical approach is sufficient for perfectly brittle and perfectly ductile structures since the cumulative distribution function (cdf) of random strength is known, making it possible to extrapolate to the tail from the mean and variance. However, the empirical approach does not apply to structures consisting of quasibrittle materials, which are brittle materials with inhomogeneities that are not negligible compared to structure size. This paper presents a refined theory on the strength distribution of quasibrittle structures, which is based on the fracture mechanics of nanocracks propagating by activation energy controlled small jumps through the atomic lattice and an analytical model for the multi-scale transition of strength statistics. Based on the power law for creep crack growth rate and the cdf of material strength, the lifetime distribution of quasibrittle structures under constant load is derived. Both the strength and lifetime cdf's are shown to be size- and geometry-dependent. The theory predicts intricate size effects on both the mean structural strength and lifetime, the latter being much stronger. The theory is shown to match the experimentally observed systematic deviations of strength and lifetime histograms of industrial ceramics from the Weibull distribution. [ABSTRACT FROM AUTHOR]

Abstract: In this work, an asymmetrical T-shaped micromixer with replaceable channels was used to investigate comparatively the micromixing performance in various micromixing configurations by Villermaux/Dushman method and CFD simulation, and the scale-up strategy of mixing configuration was discussed as well. The results show that both the convergence region and mixing channel contribute considerably to the mixing, and widening the continuous fluid channel of micromixer to several millimeters in individual can still exhibit high micromixing performance as Re is above 6000. In an asymmetrical T-shaped micromixer with a constant height of mixing channel, the intensity of mixing (I M) has a nearly linear relationship with Re in the range from 2000 to 10,000 while independent on the width of the mixing channel. Compared with one-dimension scale-up in the vertical direction, one-dimension scale-up in the horizontal direction can benefit from less deterioration to micromixing performance. Adapting for this scale-up strategy, lower mechanical energy dissipation per mass is needed at higher operational capacity. The Re can be used as a fundamental criterion for an asymmetrical T-shaped micromixer to adjust the width of mixing channel according to the operational capacity. Our results would be helpful for understanding the mixing phenomena in the asymmetrical T-shaped micromixer and optimizing configuration or operation conditions for micromixer of this kind. [Copyright &y& Elsevier]

Abstract: The desalination of surface water (lake) was performed using direct contact membrane distillation. The membrane distillation process was carried out at 358K. As a consequence of water heating the CaCO3 deposit formed on the membrane surfaces, which resulted in a decrease in module efficiency. The polyphosphate antiscalant was used for restriction of carbonate deposition. In order to increase the scaling potential during the desalination process, the water was additionally enriched with bicarbonates (feed alkalinity 3.1mmol HCO3 –/dm3 and 4.5mmol HCO3 –/dm3). The membrane distillation with and without antiscalant was carried out to evaluate the scale inhibition effect. Various solution compositions (2–20ppm) of the commercial polyphosphate based antiscalant (destined for reverse osmosis) and laboratory-grade sodium polyphosphate was used. SEM–EDS was used to investigate the chemical composition and morphology of the precipitate formed on the membrane surface. It was found that the formation of CaCO3 crystallites was almost eliminated as a result of using antiscalant. However, a thin layer of amorphous deposits on the membrane surface was observed. As a results, a decline of the permeate flux was still observed. The initial module efficiency was restored by periodical rinsing of the membranes with diluted HCl solutions. The application of antiscalant minimized the penetration of deposit into the pores, and a high permeate flux was maintained over a period of 260h of performed investigations when periodical rinsing with HCl solution was used. [Copyright &y& Elsevier]

Abstract: Operational issues arising from scaling and fouling of membranes are addressed by pre-treatment processes and alternative membrane or membrane secondary structures. In the present work the flow patterns associated with fluids within the membrane module are investigated using Computational Fluid Dynamics (CFD) tools. The effects on flow patterns through a spacer filled Reverse Osmosis (RO) membrane with the secondary structure of the membranes (feed spacer filaments) at various angles with the inlet flow are analyzed. The presence of the feed spacers in membrane module appears to generate secondary flow patterns enhancing the prospects for self induced backwashing increasing the allowable operational time and membrane efficiency. The flow visualization in the present study is useful in understanding the complex flow patterns generated in spacer filled RO membrane modules and could possibly lead to developing a new RO membrane which is more efficient, economical and appears to be a practically viable solution to reduce costs associated with the maintenance of RO membranes. [Copyright &y& Elsevier]

Based on the methods of water quality analysis, corrosion electrochemistry analysis, and X-ray diffraction, he types of the corrosion and scaling of the gathering system are studied. The results indicated that the corrosion and scaling was taken place simultaneously with the main scale of calcium and magnesium carbonate. Meanwhile, it was found that the corrosion was electrochemical erosion controlled by the cathode process. The system had high DO, Cl- and SRB content, which was the main reason of causing corrosion. By researching the protect methods against corrosion and scaling, we proposed he chemical and physical methods as technical countermeasure based on the technical process and the research results, and achieved notable effect. [ABSTRACT FROM AUTHOR]

Abstract: Nanodot and nanopillar structures and precisely controlled reproducible fabrication thereof are of great interest in common nanoelectronic devices, including photonic crystals and surface plasmon resonance instruments. In this work, fabrication process of the silicon nanopillar structures is described. It includes self-organization of gold and chromium clusters at thickness close to that of one atomic diameter to serve as etching masks followed by the reactive ion etching to form silicon nanopillars. Scanning electron microscopy and X-ray photoelectron spectroscopy were used to characterize self-organized gold and chromium clusters as well as the final silicon nanopillars. This method was found to produce silicon nanopillars of sub-10nm lateral dimensions and the diameter-to-height aspect ratio of up to 1:14. [Copyright &y& Elsevier]

Abstract: At present the annual amount of wastewater is a lot and how to deal with wastewater is a major problem. Wastewater is a prerequisite for the classification of water, wastewater sorting in a variety of methods. A classification based on the water sources of water, have the pollutants have nontoxicity classification, etc. This article will be on mechanical vapor compression techniques to classify wastewater and there is uncertainty indicator: viscosity, scaling, pH and boiling point. Wastewater is divided into three categories. [Copyright &y& Elsevier]

Drinking water network is made usually of plastic materials, concrete or metals. Drinking water supply system is affected by the corrosion and the formation of deposits on pipe surfaces. Estimation of the corrosion potential and scale-forming properties of water can be performed by the data on its pH, total alkalinity, total dissolved solids (TDS), hardness. The present paper realises an estimation of corrosion potential and scale formation on the Danube water, the main drinking water source for Galati Braila agglomerations. This estimation is necessary because there are important investments designed to increase the drinking water quality and the water supply network could be affected by these parameters. [ABSTRACT FROM AUTHOR]

This study addresses the chemical and toxicological questions due to the wide use of chemical treatment programmes for industrial cooling water. First, natural problems encountered in cooling tower systems were presented and grouped into three categories: (i) scaling; (ii) corrosion and (iii) biofouling. Chemical solutions adopted in industrial plants were outlined for each one in order to minimize damage and catagorized as shut-down, production loss, heat transfer reduction, upsets, etc. Above all, the purpose of the work was to identify the most dangerous chemicals normally used, which mean sources of chemical risk for safety workers and their environment; thus, symptoms of exposure, prevention measures and protection tools are also described. [ABSTRACT FROM PUBLISHER]