Sample records for understanding high-shear wet

  1. The effect of the physical state of binders on high-shear wet granulation and granule properties: a mechanistic approach to understand the high-shear wet granulation process. part IV. the impact of rheological state and tip-speeds. (United States)

    Li, Jinjiang; Tao, Li; Buckley, David; Tao, Jing; Gao, Julia; Hubert, Mario


    The purpose of this study is to provide a mechanistic understanding concerning the effect of tip-speed on a granulation at various binder rheological states; the in situ rheological state of a binder was controlled by exposing a granulation blend to 96% relative humidity. This approach allowed us to investigate the impact of tip-speed on granule consolidation coupled with the in situ binder state, which was not possible using a conventional granulation approach. Experimentally, the rheological state of binders was characterized using a rheometer. Granule size and granule porosity were measured by Qicpic instrument and Mercury Intrusion Porosimetry, respectively. For the granulations containing binders at viscous state (PVP K17 and PVP K29/32), the granule size increased significantly with mixing time and the growth rate increased with tip-speed until 5.8 m/s; when binders were at viscoelastic state, tip-speed had no impact on granulation. Furthermore, the granule porosity was higher for granulation with binders at viscoelastic state (HPC and PVP K90), whereas it was lower for granulation with binders at viscous state. In addition, the impeller tip-speed had minimal impact on the porosity of the final granules. Finally, Ennis' model was used for interpreting results, providing mechanistic insights on granulation. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

  2. Transfer from high-shear batch to continuous twin screw wet granulation: a case study in understanding the relationship between process parameters and product quality attributes. (United States)

    Beer, Paul; Wilson, David; Huang, Zhenyu; De Matas, Marcel


    A twin screw to high-shear batch granulation technology switch was evaluated for a pharmaceutical development project. Differences in granule (particle size distribution and porosity) and tablet (dissolution) quality attributes were analysed for both continuous and batch technologies. Liquid to solid (L/S) ratio, screw configuration and screw speed parameters on the twin screw granulator were varied, with output granule and tablet properties characterised. L/S and screw configuration were found to influence the granule particle size distribution, porosity and tablet dissolution. At 0.15 L/S, the particle size distribution showed a significant proportion of ungranulated material in the output granule. As the L/S is increased, the level of ungranulated material decreased. An increase in L/S and the number of kneader elements caused a decrease in granule porosity and tablet dissolution. Twin screw and batch granulation technologies generated different granule properties (size and shape) at a constant L/S. A lower L/S in twin screw granulation was needed to achieve similar tablet attributes. It is concluded that differences in liquid addition and therefore initial granule nucleation caused differences in granule properties, which impacted tablet attributes and manufacturability. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  3. Analysis of the origins of content non-uniformity in high-shear wet granulation. (United States)

    Oka, Sarang; Smrčka, David; Kataria, Anjali; Emady, Heather; Muzzio, Fernando; Štěpánek, František; Ramachandran, Rohit


    In this study, the origins of granule content non-uniformity in the high-shear wet granulation of a model two-component pharmaceutical blend were investigated. Using acetaminophen as the active pharmaceutical ingredient (API) and microcrystalline cellulose as the excipient, the distribution of the API across the granule size classes was measured for a range of conditions that differed in the duration of the initial dry mixing stage, the overall composition of the blend and the wet massing time. The coarse granule fractions were found to be systematically sub-potent, while the fines were enriched in the API. The extent of content non-uniformity was found to be dependent on two factors - powder segregation during dry mixing and redistribution of the API between the granule size fractions during the wet massing phase. The latter was demonstrated in an experiment where the excipient was pre-granulated, the API was added later and wet massed. The content non-uniformity in this case was comparable to that obtained when both components were present in the granulator from the beginning. With increasing wet massing time, the extent of content non-uniformity decreased, indicating that longer wet massing times might be a solution for systems with a natural tendency for component segregation. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Model-based analysis of high shear wet granulation from batch to continuous processes in pharmaceutical production - A critical review

    DEFF Research Database (Denmark)

    Kumar, Ashish; Gernaey, Krist; De Beer, Thomas


    continuous production line is still hampered by complex steps such as granulation and drying which are considered to be too inflexible to handle potential product change-overs. Granulation is necessary in order to achieve good flowability properties and better control of drug content uniformity. This paper...... reviews modelling and supporting measurement tools for the high shear wet granulation (HSWG) process, which is an important granulation technique due to the inherent benefits and the suitability of this unit operation for the desired switch to continuous mode. For gaining improved insight...... into the complete system, particle-level mechanisms are required to be better understood, and linked with an appropriate meso- or macro-scale model. A brief review has been provided to understand the mechanisms of the granulation process at micro- or particle-level such as those involving wetting and nucleation...

  5. Artificial Intelligence Tools for Scaling Up of High Shear Wet Granulation Process. (United States)

    Landin, Mariana


    The results presented in this article demonstrate the potential of artificial intelligence tools for predicting the endpoint of the granulation process in high-speed mixer granulators of different scales from 25L to 600L. The combination of neurofuzzy logic and gene expression programing technologies allowed the modeling of the impeller power as a function of operation conditions and wet granule properties, establishing the critical variables that affect the response and obtaining a unique experimental polynomial equation (transparent model) of high predictability (R 2 > 86.78%) for all size equipment. Gene expression programing allowed the modeling of the granulation process for granulators of similar and dissimilar geometries and can be improved by implementing additional characteristics of the process, as composition variables or operation parameters (e.g., batch size, chopper speed). The principles and the methodology proposed here can be applied to understand and control manufacturing process, using any other granulation equipment, including continuous granulation processes. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  6. Development of a process map: A step towards a regime map for steady-state high shear wet twin screw granulation

    DEFF Research Database (Denmark)

    Kumar, Ashish; Dhondt, Jens; Vercruysse, Jurgen


    Twin-screw granulation is an emerging continuous granulation technique in the pharmaceutical industry. The flexibility in process settings such as the binder addition method (wet vs. dry), screw configuration, screw speed and material throughput allows to modify the granule size and shape. However......, twin-screw granulation, being a rather new granulation technique, is not yet as well understood as batch-wise high shear wet granulation. Furthermore, most of the studies performed on twin-screw granulation are limited to a certain design and scale of the twin-screw granulator. In this study, in order...... to improve the understanding about the granulation process and to comprehend the applicability and limits of the process variables in a scale independent manner, the regime theory was applied to one specific twin-screw granulator equipment In this study, a-lactose monohydrate was granulated...

  7. Monitoring of multiple solvent induced form changes during high shear wet granulation and drying processes using online Raman spectroscopy. (United States)

    Reddy, Jay Poorna; Jones, John W; Wray, Patrick S; Dennis, Andrew B; Brown, Jonathan; Timmins, Peter


    Form changes during drug product processing can be a risk to the final product quality in terms of chemical stability and bioavailability. In this study, online Raman spectroscopy was used to monitor the form changes in real time during high shear wet granulation of Compound A, a highly soluble drug present at a high drug load in an extended release formulation. The effect of water content, temperature, wet massing time and drying technique on the degree of drug transformation were examined. A designed set of calibration standards were employed to develop quantitative partial least square regression models to predict the concentration of each drug form during both wet granulation and the drying process. Throughout all our experiments we observed complex changes of the drug form during granulation, manifest as conversions between the initial non-solvated form of Compound A, the hemi-hydrate form and the "apparent" amorphous form (dissolved drug). The online Raman data demonstrate that the non-solvated form converts to an "apparent" amorphous form (dissolved drug) due to drug dissolution with no appearance of the hemi-hydrate form during water addition stage. The extent of conversion of the non-solvated form was governed by the amount of water added and the rate of conversion was accelerated at higher temperatures. Interestingly, in the wet massing zone, the formation of the hemi-hydrate form was observed at a rate equivalent to the rate of depletion of the non-solvated form with no change in the level of the "apparent amorphous" form generated. The level of hemi-hydrate increased with an increase in wet massing time. The drying process had a significant effect on the proportion of each form. During tray drying, changes in drug form continued for hours. In contrast fluid bed drying appeared to lock the final proportions of drug form product attained during granulation, with comparatively small changes observed during drying. In conclusion, it was possible to

  8. Dextrose monohydrate as a non-animal sourced alternative diluent in high shear wet granulation tablet formulations. (United States)

    Mitra, Biplob; Wolfe, Chad; Wu, Sy-Juen


    The feasibility of dextrose monohydrate as a non-animal sourced diluent in high shear wet granulation (HSWG) tablet formulations was determined. Impacts of granulation solution amount and addition time, wet massing time, impeller speed, powder and solution binder, and dry milling speed and screen opening size on granule size, friability and density, and tablet solid fraction (SF) and tensile strength (TS) were evaluated. The stability of theophylline tablets TS, disintegration time (DT) and in vitro dissolution were also studied. Following post-granulation drying at 60 °C, dextrose monohydrate lost 9% water and converted into the anhydrate form. Higher granulation solution amounts and faster addition, faster impeller speeds, and solution binder produced larger, denser and stronger (less friable) granules. All granules were compressed into tablets with acceptable TS. Contrary to what is normally observed, denser and larger granules (at ≥21% water level) produced tablets with a higher TS. The TS of the weakest tablets increased the most after storage at both 25 °C/60% RH and 40 °C/75% RH. Tablet DT was higher for stronger granules and after storage. Tablet dissolution profiles for 21% or less water were comparable and did not change on stability. However, the dissolution profile for tablets prepared with 24% water was slower initially and continued to decrease on stability. The results indicate a granulation water amount of not more than 21% is required to achieve acceptable tablet properties. This study clearly demonstrated the utility of dextrose monohydrate as a non-animal sourced diluent in a HSWG tablet formulation.

  9. Model-based analysis of high shear wet granulation from batch to continuous processes in pharmaceutical production--a critical review. (United States)

    Kumar, Ashish; Gernaey, Krist V; De Beer, Thomas; Nopens, Ingmar


    The manufacturing of pharmaceutical dosage forms, which has traditionally been a batch-wise process, is now also transformed into a series of continuous operations. Some operations such as tabletting and milling are already performed in continuous mode, while the adaptation towards a complete continuous production line is still hampered by complex steps such as granulation and drying which are considered to be too inflexible to handle potential product change-overs. Granulation is necessary in order to achieve good flowability properties and better control of drug content uniformity. This paper reviews modelling and supporting measurement tools for the high shear wet granulation (HSWG) process, which is an important granulation technique due to the inherent benefits and the suitability of this unit operation for the desired switch to continuous mode. For gaining improved insight into the complete system, particle-level mechanisms are required to be better understood, and linked with an appropriate meso- or macro-scale model. A brief review has been provided to understand the mechanisms of the granulation process at micro- or particle-level such as those involving wetting and nucleation, aggregation, breakage and consolidation. Further, population balance modelling (PBM) and the discrete element method (DEM), which are the current state-of-the-art methods for granulation modelling at micro- to meso-scale, are discussed. The DEM approach has a major role to play in future research as it bridges the gap between micro- and meso-scales. Furthermore, interesting developments in the measurement technologies are discussed with a focus towards inline measurements of the granulation process to obtain experimental data which are required for developing good models. Based on the current state of the developments, the review focuses on the twin-screw granulator as a device for continuous HSWG and attempts to critically evaluate the current process. As a result, a set of open

  10. Process Analytical Technology for High Shear Wet Granulation: Wet Mass Consistency Reported by In-Line Drag Flow Force Sensor Is Consistent With Powder Rheology Measured by At-Line FT4 Powder Rheometer. (United States)

    Narang, Ajit S; Sheverev, Valery; Freeman, Tim; Both, Douglas; Stepaniuk, Vadim; Delancy, Michael; Millington-Smith, Doug; Macias, Kevin; Subramanian, Ganeshkumar


    Drag flow force (DFF) sensor that measures the force exerted by wet mass in a granulator on a thin cylindrical probe was shown as a promising process analytical technology for real-time in-line high-resolution monitoring of wet mass consistency during high shear wet granulation. Our previous studies indicated that this process analytical technology tool could be correlated to granulation end point established independently through drug product critical quality attributes. In this study, the measurements of flow force by a DFF sensor, taken during wet granulation of 3 placebo formulations with different binder content, are compared with concurrent at line FT4 Powder Rheometer characterization of wet granules collected at different time points of the processing. The wet mass consistency measured by the DFF sensor correlated well with the granulation's resistance to flow and interparticulate interactions as measured by FT4 Powder Rheometer. This indicated that the force pulse magnitude measured by the DFF sensor was indicative of fundamental material properties (e.g., shear viscosity and granule size/density), as they were changing during the granulation process. These studies indicate that DFF sensor can be a valuable tool for wet granulation formulation and process development and scale up, as well as for routine monitoring and control during manufacturing. Copyright © 2016. Published by Elsevier Inc.

  11. Process understanding on high shear granulated lactose agglomerates during and after drying

    NARCIS (Netherlands)

    Nieuwmeyer, F.J.S.


    In 2001 the FDA launched the Process Analytical Technology initiative as a response to the growing public and industrial awareness that there is a lack of process understanding required to have an optimal control of pharmaceutical manufacturing. The current research project was initiated based upon

  12. SEDflume - High Shear Stress Flume (United States)

    Federal Laboratory Consortium — The U.S. Army Corps of Engineers High Shear Stress flume (SEDflume) is designed for estimating erosion rates of fine-grained and mixed fine/coarse grained sediments...

  13. Understanding the edge effect in wetting: a thermodynamic approach. (United States)

    Fang, Guoping; Amirfazli, A


    Edge effect is known to hinder spreading of a sessile drop. However, the underlying thermodynamic mechanisms responsible for the edge effect still is not well-understood. In this study, a free energy model has been developed to investigate the energetic state of drops on a single pillar (from upright frustum to inverted frustum geometries). An analysis of drop free energy levels before and after crossing the edge allows us to understand the thermodynamic origin of the edge effect. In particular, four wetting cases for a drop on a single pillar with different edge angles have been determined by understanding the characteristics of FE plots. A wetting map describing the four wetting cases is given in terms of edge angle and intrinsic contact angle. The results show that the free energy barrier observed near the edge plays an important role in determining the drop states, i.e., (1) stable or metastable drop states at the pillar's edge, and (2) drop collapse by liquid spilling over the edge completely or staying at an intermediate sidewall position of the pillar. This thermodynamic model presents an energetic framework to describe the functioning of the so-called "re-entrant" structures. Results show good consistency with the literature and expand the current understanding of Gibbs' inequality condition.

  14. A Comparison of Granules Produced by High-Shear and Fluidized-Bed Granulation Methods


    Morin, Garett; Briens, Lauren


    Placebo granules were manufactured by both wet high-shear and fluidized-bed techniques. The granules were compared based on size, shape, surface morphology, and a variety of different flowability measurements. This comparison showed that granule formation and growth were different, with induction growth for high-shear granulation and steady growth for fluidized-bed granulation. Final granules from high-shear granulation were more spherical and dense compared with the irregular granules from f...

  15. A comparison of granules produced by high-shear and fluidized-bed granulation methods. (United States)

    Morin, Garett; Briens, Lauren


    Placebo granules were manufactured by both wet high-shear and fluidized-bed techniques. The granules were compared based on size, shape, surface morphology, and a variety of different flowability measurements. This comparison showed that granule formation and growth were different, with induction growth for high-shear granulation and steady growth for fluidized-bed granulation. Final granules from high-shear granulation were more spherical and dense compared with the irregular granules from fluidized-bed granulation. The high-shear granules demonstrated better overall flow properties.

  16. The relation between granule size, granule stickiness, and torque in the high-shear granulation process

    NARCIS (Netherlands)

    Bouwman, A.M.; Henstra, M.J.; Hegge, J.J.M.E.; Zhang, Z.; Ingram, A.; Seville, J.P.K.; Frijlink, H.W.


    Purpose. To investigate the background of the observed relationship between measured torque and granule size in high-shear granulation processes. Methods. Torque was measured during the granulation process; the behavior of individual wet granules during compaction was investigated using

  17. A review of monitoring methods for pharmaceutical wet granulation. (United States)

    Hansuld, E M; Briens, L


    High-shear wet granulation is commonly used in the pharmaceutical industry to improve powder properties for downstream processes such as tabletting. Granule growth, however, is difficult to predict because the process is sensitive to raw material properties and operating conditions. Development of process analytical technologies is encouraged by regulatory bodies to improve process understanding and monitor quality online. The primary technologies investigated for high-shear wet granulation monitoring include power consumption, near-infrared spectroscopy, Raman spectroscopy, capacitance measurements, microwave measurements, imaging, focused beam reflectance measurements, spatial filter velocimetry, stress and vibration measurements, as well as acoustic emissions. This review summarizes relevant research related to each of these technologies and discusses the challenges associated with each approach as a possible process analytical technology tool for high-shear wet granulation. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Educators' understanding of workplace bullying | de Wet | South ...

    African Journals Online (AJOL)

    This article looks at educators' understanding of workplace bullying through the lens of a twodimensional model of bullying. Educators, who were furthering their studies at the University of the Free State, were invited to take part in a study on different types of bullying. Deductive, directed content analysis was used to ...

  19. Topographic characterization of polymer materials at different length scales and the mechanistic understanding of wetting phenomena


    Calvimontes, Alfredo


    The present study suggests new insights into topographic characterisation of engineering polymer surfaces towards to physical-chemical and mechanistic understanding of wetting phenomena on rough surfaces. Non-contact chromatic confocal imaging was chosen and justified as the optimal measuring method to study and correlate surface topography and surface properties of Sheet Moulding Compounds (SMC) as well as polyester and cotton fabrics. Before topographical characterisation, an adequate se...

  20. High-shear granulation as a manufacturing method for cocrystal granules

    DEFF Research Database (Denmark)

    Rehder, Sönke; Christensen, Niels Peter Aae; Rantanen, Jukka


    influenced by the excipients, since in presence of calcium hydrogenphosphate, the poorly water-soluble salt calcium tartrate monohydrate was formed at high relative humidity. Interestingly, compactability was increased by cocrystal formation compared to that of the reference granules (piracetam......Cocrystal formation allows the tailoring of physicochemical as well as of mechanical properties of an API. However, there is a lack of large-scale manufacturing methods of cocrystals. Therefore, the objective of this work was to examine the suitability of high-shear wet granulation...... as a manufacturing method for cocrystal granules on a batch scale. Furthermore, the cocrystal granules were characterized regarding their mechanical properties as well as their dissolution behavior. High-shear wet granulation was found to be a feasible manufacturing method for cocrystal granules. Cocrystal formation...

  1. Cascading hazards: Understanding triggering relations between wet tropical cyclones, landslides, and earthquakes (United States)

    Wdowinski, S.; Peng, Z.; Ferrier, K.; Lin, C. H.; Hsu, Y. J.; Shyu, J. B. H.


    Earthquakes, landslides, and tropical cyclones are extreme hazards that pose significant threats to human life and property. Some of the couplings between these hazards are well known. For example, sudden, widespread landsliding can be triggered by large earthquakes and by extreme rainfall events like tropical cyclones. Recent studies have also shown that earthquakes can be triggered by erosional unloading over 100-year timescales. In a NASA supported project, titled "Cascading hazards: Understanding triggering relations between wet tropical cyclones, landslides, and earthquake", we study triggering relations between these hazard types. The project focuses on such triggering relations in Taiwan, which is subjected to very wet tropical storms, landslides, and earthquakes. One example for such triggering relations is the 2009 Morakot typhoon, which was the wettest recorded typhoon in Taiwan (2850 mm of rain in 100 hours). The typhoon caused widespread flooding and triggered more than 20,000 landslides, including the devastating Hsiaolin landslide. Six months later, the same area was hit by the 2010 M=6.4 Jiashian earthquake near Kaohsiung city, which added to the infrastructure damage induced by the typhoon and the landslides. Preliminary analysis of temporal relations between main-shock earthquakes and the six wettest typhoons in Taiwan's past 50 years reveals similar temporal relations between M≥5 events and wet typhoons. Future work in the project will include remote sensing analysis of landsliding, seismic and geodetic monitoring of landslides, detection of microseismicity and tremor activities, and mechanical modeling of crustal stress changes due to surface unloading.

  2. Optimization of the High-Shear Wet Granulation Wetting Process Using Fuzzy Logic Modeling

    Czech Academy of Sciences Publication Activity Database

    Bělohlav, Z.; Břenková, L.; Kalčíková, J.; Hanika, Jiří; Durdil, P.; Tomášek, V.; Palatová, M.


    Roč. 12, č. 4 (2007), s. 345-352 ISSN 1083-7450 Institutional research plan: CEZ:AV0Z40720504 Keywords : fuzzy logic * mathematical model * granulation Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 0.876, year: 2007

  3. Scale-down of a high-shear pelletisation process : Flow profile and growth kinetics

    NARCIS (Netherlands)

    Ramaker, JS; Jelgersma, MA; Vonk, P; Kossen, NWF


    For the predictive modelling of the high-shear pelletisation process it is necessary to have a better understanding of the underlying mechanisms. Therefore, pelletisation experiments were carried out with microcrystalline cellulose and lactose in a coffee grinder (small-scale) and in a Gral 10

  4. Quantitative analysis of precipitation over Fukushima to understand the wet deposition process in March 2011 (United States)

    Yatagai, A.; Onda, Y.; Watanabe, A.


    The Great East Japan Earthquake caused a severe accident at the Fukushima-Daiichi nuclear power plant (NPP), leading to the emission of large amounts of radioactive pollutants into the environment. The transport and diffusion of these radioactive pollutants in the atmosphere caused a disaster for residents in and around Fukushima. Studies have sought to understand the transport, diffusion, and deposition process, and to understand the movement of radioactive pollutants through the soil, vegetation, rivers, and groundwater. However, a detailed simulation and understanding of the distribution of radioactive compounds depend on a simulation of precipitation and on the information on the timing of the emission of these radioactive pollutants from the NPP. Past nuclear expansion studies have demonstrated the importance of wet deposition in distributing pollutants. Hence, this study examined the quantitative precipitation pattern in March 2011 using rain-gauge observations and X-band radar data from Fukushima University. We used the AMeDAS rain-gauge network data of 1) the Japan Meteorological Agency (1273 stations in Japan) and 2) the Water Information System (47 stations in Fukushima prefecture) and 3) the rain-gauge data of the Environmental Information Network of NTT Docomo (30 stations in Fukushima) to construct 0.05-degree mesh data using the same method used to create the APHRODITE daily grid precipitation data (Yatagai et al., 2009). Since some AMeDAS data for the coastal region were lost due to the earthquake, the complementary network of 2) and 3) yielded better precipitation estimates. The data clarified that snowfall was observed on the night of Mar 15 into the morning of Mar 16 throughout Fukushima prefecture. This had an important effect on the radioactive contamination pattern in Fukushima prefecture. The precipitation pattern itself does not show one-on-one correspondence with the contamination pattern. While the pollutants transported northeast of the

  5. Understanding the wetting properties of nanostructured selenium coatings: the role of nanostructured surface roughness and air-pocket formation

    Directory of Open Access Journals (Sweden)

    Tran PA


    Full Text Available Phong A Tran,1,2 Thomas J Webster31Department of Chemical and Biomolecular Engineering, University of Melbourne, Melbourne, VIC, Australia; 2The Particulate Fluid Processing Centre, University of Melbourne, Melbourne, VIC, Australia; 3Department of Chemical Engineering and Program in Bioengineering, Northeastern University, Boston, MA, USAAbstract: Wetting properties of biomaterials, in particular nanomaterials, play an important role, as these influence interactions with biological elements, such as proteins, bacteria, and cells. In this study, the wetting phenomenon of titanium substrates coated with selenium nanoparticles was studied using experimental and mathematical modeling tools. Importantly, these selenium-coated titanium substrates were previously reported to increase select protein adsorption (such as vitronectin and fibronectin, to decrease bacteria growth, and increase bone cell growth. Increased selenium nanoparticle coating density resulted in higher contact angles but remained within the hydrophilic regime. This trend was found in disagreement with the Wenzel model, which is widely used to understand the wetting properties of rough surfaces. The trend also did not fit well with the Cassie–Baxter model, which was developed to understand the wetting properties of composite surfaces. A modified wetting model was thus proposed in this study, to understand the contributing factors of material properties to the hydrophilicity/hydrophobicity of these nanostructured selenium-coated surfaces. The analysis and model created in this study can be useful in designing and/or understanding the wetting behavior of numerous biomedical materials and in turn, biological events (such as protein adsorption as well as bacteria and mammalian cell functions.Keywords: hydrophilicity, hydrophobicity, Wenzel model, Cassie–Baxter model, free energy, implant material, proteins, cells, bacteria

  6. Linked Min.B configuration inside high shear magnetic surface

    International Nuclear Information System (INIS)

    Ohasa, K.; Ikuta, K.


    Arrangement of the l = m baseball coils to form the toroidally linked Min.B configuration with large rotational transform is studied analytically and numerically. By an optimization the closed magnetic isobars are obtained inside the last closed magnetic surface having practical volume and high shear if l = 3 baseball coils are arranged. (auth.)

  7. Fluid bed granulation of a poorly water soluble, low density, micronized drug: comparison with high shear granulation. (United States)

    Gao, Julia Z H; Jain, A; Motheram, R; Gray, D B; Hussain, M A


    A 2(4-1) fractional factorial design was used to evaluate the effect of various process variables in fluid bed granulation, on the physico-chemical properties of granule and tablet containing a high dose, poorly water soluble, low density, and micronized drug. The process variables studied were inlet air temperature, inlet air flow, spray rate of the binder solution, and atomization air pressure. Tablets with identical composition, weight, size and hardness were also manufactured in a high shear granulator and their physical properties were determined and compared with those produced by the fluidized bed granulation method. Except for the granule size distribution, other physical properties of granulations and tablets produced in a fluid bed granulator are independent of the selected process variables within the study range. Both atomization air pressure and spray rate of the binder solution had strong impact on granule size distribution. Irrespective of the process conditions used in the fluid bed granulation, granules from this process were more porous, less dense and more compressible than the granules from the high shear granulation process. Comparable tablet dissolution rates to those prepared by the optimized high shear granulation method can be achieved by selecting the appropriate process conditions in fluid bed granulation. These results suggest that wet granulation tablets of a high dose, poorly water soluble, low density, micronized drug can be manufactured using a fluidized bed granulation method, with comparable tablet dissolution rates to those produced with an optimized high shear granulation method.

  8. In-depth experimental analysis of pharmaceutical twin-screw wet granulation in view of detailed process understanding. (United States)

    Verstraeten, Maxim; Van Hauwermeiren, Daan; Lee, Kai; Turnbull, Neil; Wilsdon, David; Am Ende, Mary; Doshi, Pankaj; Vervaet, Chris; Brouckaert, Davinia; Mortier, Séverine T F C; Nopens, Ingmar; Beer, Thomas De


    Twin-screw wet granulation is gaining increasing interest within the pharmaceutical industry for the continuous manufacturing of solid oral dosage forms. However, limited prior fundamental physical understanding has been generated relating to the granule formation mechanisms and kinetics along the internal compartmental length of a twin-screw granulator barrel, and about how process settings, barrel screw configuration and formulation properties such as particle size, density and surface properties influence these mechanisms. One of the main reasons for this limited understanding is that experimental data is generally only collected at the exit of the twin-screw granulator barrel although the granule formation occurs spatially along the internal length of the barrel. The purpose of this study is to analyze the twin-screw wet granulation process using both hydrophilic and hydrophobic formulations, manufactured under different process settings such as liquid-to-solid ratio, mass throughput and screw speed, in such a way that the mechanisms occurring in the individual granulator barrel compartments (i.e., the wetting and different conveying and kneading compartments) and their impact upon granule formation are understood. To achieve this, a unique experimental setup was developed allowing granule characteristic data-collection such as size, shape, liquid and porosity distribution at the different compartments along the length of the granulator barrel. Moreover, granule characteristic information per granule size class was determined. The experimental results indicated that liquid-to-solid ratio is the most important factor dictating the formation of the granules and their corresponding properties, by regulating the degree of aggregation and breakage in the different compartments along the internal length of the twin-screw granulator barrel. Collecting appropriate and detailed experimental data about granule formation along the internal length of the granulator barrel

  9. Hijama therapy (wet cupping) - its potential use to complement British healthcare in practice, understanding, evidence and regulation. (United States)

    Sajid, Mohammed Imran


    Wet cupping was used in the nineteenth century for treatment of patients in the United Kingdom (UK) by a few experienced practitioners. Revival Hijama use by practitioners in the UK in recent years has been observed as well as interest from the public, with developments of specific certified training programmes, established businesses providing tailored Hijama therapy Clinical Waste disposal services, provisions of insurance cover, involvement of medical professionals and membership with the General Regulatory Council for Complementary Therapies (GRCCT). However, there has also been noted that there is not much in the way of guidance or regulation. Therefore, we would like to initiate some communication and understanding of Hijama (wet cupping) to benefit medical professionals, discussing recent research undertaken as a basis for potentially more in the future (evidence-based practice), in the likely event that a patient might request to be referred for this therapy during a consultation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Understanding and Managing Aging of Spent Nuclear Fuel and Facility Components in Wet Storage

    International Nuclear Information System (INIS)

    Johnson, A. B.


    Storage of nuclear fuel after it has been discharged from reactors has become the leading spent fuel management option. Many storage facilities are being required to operate longer than originally anticipated. Aging is a term that has emerged to focus attention on the consequences of extended operation on systems, structures, and components that comprise the storage facilities. The key to mitigation of age-related degradation in storage facilities is to implement effective strategies to understand and manage aging of the facility materials. A systematic approach to preclude serious effects of age-related degradation is addressed in this paper, directed principally to smaller facilities (test and research reactors). The first need is to assess the materials that comprise the facility and the environments that they are subject to. Access to historical data on facility design, fabrication, and operation can facilitate assessment of expected materials performance. Methods to assess the current condition of facility materials are summarized in the paper. Each facility needs an aging management plan to define the scope of the management program, involving identification of the materials that need specific actions to manage age-related degradation. For each material identified, one or more aging management programs are developed and become part of the plan Several national and international organizations have invested in development of comprehensive and systematic approaches to aging management. A method developed by the US Nuclear Regulatory Commission is recommended as a concise template to organize measures to effectively manage age-related degradation of storage facility materials, including the scope of inspection, surveillance, and maintenance that is needed to assure successful operation of the facility over its required life. Important to effective aging management is a staff that is alert for evidence of materials degradation and committed to carry out the aging

  11. New gentle-wing high-shear granulator: impact of processing variables on granules and tablets characteristics of high-drug loading formulation using design of experiment approach. (United States)

    Fayed, Mohamed H; Abdel-Rahman, Sayed I; Alanazi, Fars K; Ahmed, Mahrous O; Tawfeek, Hesham M; Al-Shdefat, Ramadan I


    The aim of this work was to study the application of design of experiment (DoE) approach in defining design space for granulation and tableting processes using a novel gentle-wing high-shear granulator. According to quality-by-design (QbD) prospective, critical attributes of granules, and tablets should be ensured by manufacturing process design. A face-centered central composite design has been employed in order to investigate the effect of water amount (X 1 ), impeller speed (X 2 ), wet massing time (X 3 ), and water addition rate (X 4 ) as independent process variables on granules and tablets characteristics. Acetaminophen was used as a model drug and granulation experiments were carried out using dry addition of povidone k30. The dried granules have been analyzed for their size distribution, density, and flow pattern. Additionally, the produced tablets have been investigated for; weight uniformity, breaking force, friability and percent capping, disintegration time, and drug dissolution. Results of regression analysis showed that water amount, impeller speed and wet massing time have significant (p tablets characteristics. However, the water amount had the most pronounced effect as indicated by its higher parameter estimate. On the other hand, water addition rate showed a minimal impact on granules and tablets properties. In conclusion, water amount, impeller speed, and wet massing time could be considered as critical process variables. Thus, understanding the relationship between these variables and quality attributes of granules and corresponding tablets provides the basis for adjusting granulation variables in order to optimize product performance.

  12. Thermoplastic encapsulation of waste surrogates by high-shear mixing

    International Nuclear Information System (INIS)

    Lageraaen, P.R.; Kalb, P.D.; Patel, B.R.


    Brookhaven National Laboratory (BNL) has developed a robust, extrusion-based polyethylene encapsulation process applicable to a wide range of solid and aqueous low-level radioactive, hazardous and mixed wastes. However, due to the broad range of physical and chemical properties of waste materials, pretreatment of these wastes is often required to make them amenable to processing with polyethylene. As part of the scope of work identified in FY95 open-quotes Removal and Encapsulation of Heavy Metals from Ground Water,close quotes EPA SERDP No. 387, that specifies a review of potential thermoplastic processing techniques, and in order to investigate possible pretreatment alternatives, BNL conducted a vendor test of the Draiswerke Gelimat (thermokinetic) mixer on April 25, 1995 at their test facility in Mahwah, NJ. The Gelimat is a batch operated, high-shear, high-intensity fluxing mixer that is often used for mixing various materials and specifically in the plastics industry for compounding additives such as stabilizers and/or colorants with polymers

  13. How Do You Like Your Science, Wet or Dry? How Two Lab Experiences Influence Student Understanding of Science Concepts and Perceptions of Authentic Scientific Practice (United States)

    Munn, Maureen; Knuth, Randy; Van Horne, Katie; Shouse, Andrew W.; Levias, Sheldon


    This study examines how two kinds of authentic research experiences related to smoking behavior--genotyping human DNA (wet lab) and using a database to test hypotheses about factors that affect smoking behavior (dry lab)--influence students' perceptions and understanding of scientific research and related science concepts. The study used pre and…

  14. Optimization of melt pelletization in a high shear mixer. (United States)

    Bukovec, P; Kroselj, V; Turk, S; Vrecer, F


    The effects of process conditions and binder content on the process yield and pellet characteristics of two formulations prepared by melt pelletization in a laboratory-type high shear mixer were investigated. The formulations were prepared using Gelucire 50/13 and Lutrol F68 as meltable binders. The factors under investigation were impeller speed, mixing time, mixer load, binder concentration, and their reciprocal interactions. Analysis of variance (ANOVA) was used in order to study the significance of above mentioned process variables on the useful yield. Twenty-seven experiments were required for the response surface methodology based on Box-Behnken experimental design (24 combinations with three replications of the centre point) for each formulation. The control over the process and the quality of the resulting pellets were found to depend on the rheological properties of the binders used. In the case of a low viscosity binder (Gelucire 50/13), the process was easily controllable whereas in the case of a high viscosity binder (Lutrol F68), the process was more difficult to control. The useful yield of the formulation in the case of the low viscosity binder was found to be mostly influenced by the concentration of the binder. On the other hand, different binder concentrations did not affect the useful yield of the formulation prepared by use of the high viscosity binder. In the latter case, mixing time was identified as the variable that mostly influenced the pelletization process. Finally response surface methodology was applied to find the optimum values of the process variables.

  15. 3D Simulations of NIF Wetted Foam Experiments to Understand the Transition from 2D to 3D Implosion Behavior (United States)

    Haines, Brian; Olson, Richard; Yi, Austin; Zylstra, Alex; Peterson, Robert; Bradley, Paul; Shah, Rahul; Wilson, Doug; Kline, John; Leeper, Ramon; Batha, Steve


    The high convergence ratio (CR) of layered Inertial Confinement Fusion capsule implosions contribute to high performance in 1D simulations yet make them more susceptible to hydrodynamic instabilities, contributing to the development of 3D flows. The wetted foam platform is an approach to hot spot ignition to achieve low-to-moderate convergence ratios in layered implosions on the NIF unobtainable using an ice layer. Detailed high-resolution modeling of these experiments in 2D and 3D, including all known asymmetries, demonstrates that 2D hydrodynamics explain capsule performance at CR 12 but become less suitable as the CR increases. Mechanisms for this behavior and detailed comparisons of simulations to experiments on NIF will be presented. To evaluate the tradeoff between increased instability and improved 1D performance, we present a full-scale wetted foam capsule design with 17

  16. Selective recovery of pure copper nanopowder from indium-tin-oxide etching wastewater by various wet chemical reduction process: Understanding their chemistry and comparisons of sustainable valorization processes. (United States)

    Swain, Basudev; Mishra, Chinmayee; Hong, Hyun Seon; Cho, Sung-Soo


    Sustainable valorization processes for selective recovery of pure copper nanopowder from Indium-Tin-Oxide (ITO) etching wastewater by various wet chemical reduction processes, their chemistry has been investigated and compared. After the indium recovery by solvent extraction from ITO etching wastewater, the same is also an environmental challenge, needs to be treated before disposal. After the indium recovery, ITO etching wastewater contains 6.11kg/m(3) of copper and 1.35kg/m(3) of aluminum, pH of the solution is very low converging to 0 and contain a significant amount of chlorine in the media. In this study, pure copper nanopowder was recovered using various reducing reagents by wet chemical reduction and characterized. Different reducing agents like a metallic, an inorganic acid and an organic acid were used to understand reduction behavior of copper in the presence of aluminum in a strong chloride medium of the ITO etching wastewater. The effect of a polymer surfactant Polyvinylpyrrolidone (PVP), which was included to prevent aggregation, to provide dispersion stability and control the size of copper nanopowder was investigated and compared. The developed copper nanopowder recovery techniques are techno-economical feasible processes for commercial production of copper nanopowder in the range of 100-500nm size from the reported facilities through a one-pot synthesis. By all the process reported pure copper nanopowder can be recovered with>99% efficiency. After the copper recovery, copper concentration in the wastewater reduced to acceptable limit recommended by WHO for wastewater disposal. The process is not only beneficial for recycling of copper, but also helps to address environment challenged posed by ITO etching wastewater. From a complex wastewater, synthesis of pure copper nanopowder using various wet chemical reduction route and their comparison is the novelty of this recovery process. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Construction and Deployment of Tilt Sensors along the Lateral Margins of Jarvis Glacier, Alaska to improve understanding of the Deformation Regime of Wet-Based Polythermal Glaciers (United States)

    Lee, I. R.; Hawley, R. L.; Clemens-Sewall, D.; Campbell, S. W.; Waszkiewicz, M.; Bernsen, S.; Gerbi, C. C.; Kreutz, K. J.; Koons, P. O.


    Most studies of natural ice have been on bodies of ice with frozen beds which experience minimal lateral shear strain, to the exclusion of polythermal ice sheets & glaciers which due to their mixed basal thermal regime have wet-based beds. The deficiency in knowledge and understanding of the operative deformation mechanisms of wet-based bodies of ice results in uncertainty in the constitutive flow law of ice. Given that the flow law was derived experimentally under assumptions more conducive to bodies of ice with frozen-based beds, it is necessary to calibrate the flow law when applied to different bodies of ice such as wet-based polythermal glaciers. To this end, Dartmouth and the University of Maine have collaborated to carry out research on Jarvis Glacier in Alaska, a geometrically simple, wet-based glacier. Here, we constructed and deployed an array of 25 tilt sensors into 3 boreholes drilled along the glacier's shear margin. Our goal is to obtain 3D strain measurements to calculate the full velocity field & create deformation regime maps in the vicinity of the boreholes, as well as to support numerical modeling. The tilt sensors were developed in-lab: Each tilt sensor comes equipped with an LSM303C chip (embedded with a 3-axis accelerometer and magnetometer) and Arduino Pro-Mini mounted on a custom-made printed circuit board encased within a watertight aluminum tube. The design concept was to produce a sensor string, consisting of tilt sensors spaced apart at pre-calculated intervals, to be lowered into a borehole and frozen-in over months to collect strain data through a Campbell Scientific CR1000 datalogger. Three surface-to-bed boreholes were successfully installed with tilt sensor strings. Given the lack of prior in-situ borehole geophysics studies on polythermal glaciers, deliberate consideration on factors such as strain relief and waterproofing electrical components was necessary in the development of the sensor system. On-site challenges also arose due

  18. Morphology and mechanical properties of PA12/plasticized starch blends prepared by high-shear extrusion

    International Nuclear Information System (INIS)

    Teyssandier, F.; Cassagnau, P.; Gérard, J.F.; Mignard, N.; Mélis, F.


    Highlights: ► High shear rate processing was found to greatly impact PA12/starch blend morphologies. ► The morphology was observed to be stable under subsequent processing conditions. ► The mechanical properties of the blends under high-shear rate were greatly improved. ► Polymer blend preparation via high-shear processing has proved to be very effective. ► Finally, polymer blends with improved mechanical properties were obtained. - Abstract: PA12/plasticized starch blends (PA12/TPS) were prepared by high-shear twin screw extruder. The morphology development and the mechanical properties of the blends were investigated as a function of the apparent shear rate. High-shear processing has proved to be an efficient method to finely disperse thermoplastic starch in polyamide 12 matrix. Blends containing TPS domains with a size at the nano-scale (R n ∼ 150 nm) homogeneously dispersed in PA12 matrix were obtained. From a modeling point of view, the variation of the droplet radius is closer to the Wu's predictions compared to the Serpe's predictions. From the basic hypothesis of these models, it can be then assumed that compatibilization between both phases occurs during the blend processing. Furthermore, this morphology of the blends has been proved to be stable after a reprocessing step in an internal mixer most likely due to either strong hydrogen bonds between the hydroxyl groups of starch and amide groups of polyamide 12 or to potentially cross reactions between macroradicals accounting for in situ formation of graft copolymers with the potential function of compatibilizers. Mechanical properties of the blends were found to be strongly dependent on the shear rate parameter of blend processing as the mechanical properties increase with shear rate. In agreement to the blend morphology, the elongation at break of the blends was greatly improved attesting of a good adhesion between both phases.

  19. Cohesion and agglomeration of wet powders (United States)

    Raux, Pascal S.; Biance, Anne-Laure


    Wet high-shear granulation consists in vigorously mixing grains and a liquid binder to create agglomerates of various sizes. The process results from a balance between cohesion of the wet granular agglomerates and fragmentation due to the high mixing. By performing a simple test with glass beads and various liquids, we first focus on the static cohesion of wet granular media. Contrary to previous works, we extend the study to larger values of the liquid fraction w . After the well-documented plateau, the cohesive strength increases again with w , a behavior we capture by a simple model. We then focus on the dynamical cohesion of the media and we design an agglomeration process that consists in vibrating a bead/liquid mixture at a large amplitude. The vibrations induce not only the fluidization of the wet granular material but also the formation of aggregates. As expected, their size is affected by the liquid content, the frequency, and the amplitude of the vibrations, similarly to high-shear granulation data. However, the number of beads in an agglomerate does not depend on the bead size, showing a self-similar mechanism of agglomeration. The role of the static cohesion strength in this dynamical process remains therefore ambiguous.

  20. Selective recovery of pure copper nanopowder from indium-tin-oxide etching wastewater by various wet chemical reduction process: Understanding their chemistry and comparisons of sustainable valorization processes

    International Nuclear Information System (INIS)

    Swain, Basudev; Mishra, Chinmayee; Hong, Hyun Seon; Cho, Sung-Soo


    Sustainable valorization processes for selective recovery of pure copper nanopowder from Indium-Tin-Oxide (ITO) etching wastewater by various wet chemical reduction processes, their chemistry has been investigated and compared. After the indium recovery by solvent extraction from ITO etching wastewater, the same is also an environmental challenge, needs to be treated before disposal. After the indium recovery, ITO etching wastewater contains 6.11 kg/m 3 of copper and 1.35 kg/m 3 of aluminum, pH of the solution is very low converging to 0 and contain a significant amount of chlorine in the media. In this study, pure copper nanopowder was recovered using various reducing reagents by wet chemical reduction and characterized. Different reducing agents like a metallic, an inorganic acid and an organic acid were used to understand reduction behavior of copper in the presence of aluminum in a strong chloride medium of the ITO etching wastewater. The effect of a polymer surfactant Polyvinylpyrrolidone (PVP), which was included to prevent aggregation, to provide dispersion stability and control the size of copper nanopowder was investigated and compared. The developed copper nanopowder recovery techniques are techno-economical feasible processes for commercial production of copper nanopowder in the range of 100–500 nm size from the reported facilities through a one-pot synthesis. By all the process reported pure copper nanopowder can be recovered with>99% efficiency. After the copper recovery, copper concentration in the wastewater reduced to acceptable limit recommended by WHO for wastewater disposal. The process is not only beneficial for recycling of copper, but also helps to address environment challenged posed by ITO etching wastewater. From a complex wastewater, synthesis of pure copper nanopowder using various wet chemical reduction route and their comparison is the novelty of this recovery process. - Highlights: • From the Indium-Tin-Oxide etching wastewater

  1. High Shear Stresses under Exercise Condition Destroy Circulating Tumor Cells in a Microfluidic System


    Regmi, Sagar; Fu, Afu; Luo, Kathy Qian


    Circulating tumor cells (CTCs) are the primary targets of cancer treatment as they cause distal metastasis. However, how CTCs response to exercise-induced high shear stress is largely unknown. To study the effects of hemodynamic microenvironment on CTCs, we designed a microfluidic circulatory system that produces exercise relevant shear stresses. We explore the effects of shear stresses on breast cancer cells with different metastatic abilities, cancer cells of ovarian, lung and leukemic orig...

  2. Development and optimization of solid dispersion containing pellets of itraconazole prepared by high shear pelletization. (United States)

    Ye, Guanhao; Wang, Siling; Heng, Paul Wan Sia; Chen, Ling; Wang, Chao


    This study investigated the solid dispersion containing pellets of itraconazole for enhanced drug dissolution rate. The influence of process parameters used during high shear pelletization on the pellet properties including pellet size and dissolution rate was also studied. Solid dispersions of itraconazole were prepared with Eudragit E100, a hydrophilic polymer, by a simple fusion method followed by powdered and characterized by differential scanning calorimetry and X-ray powder diffraction. Solid dispersions containing pellets were consequently prepared using a lab-scale high shear mixer. In order to improve the product quality, a central composite design was applied to optimize the critical process variables, such as impeller speed and kneading time, and the results were modeled statistically. Itraconazole was presented as an amorphous state in the solid dispersion prepared at a drug to polymer ratio of 1:2. Both studied parameters had great effect on the responses. Powdered solid dispersion and pellets prepared using the optimal parameter settings showed approximately 30- and 70-fold increases in dissolution rate over the pure drug, respectively. Solid dispersion prepared by simple fusion method could be an option for itraconazole solubility enhancement. Pelletization process in high shear mixer can be optimized effectively by central composite design.

  3. PREFACE: Dynamics of wetting Dynamics of wetting (United States)

    Grest, Gary S.; Oshanin, Gleb; Webb, Edmund B., III


    Capillary phenomena associated with fluids wetting other condensed matter phases have drawn great scientific interest for hundreds of years; consider the recent bicentennial celebration of Thomas Young's paper on equilibrium contact angles, describing the geometric shape assumed near a three phase contact line in terms of the relevant surface energies of the constituent phases [1]. Indeed, nearly a century has passed since the seminal papers of Lucas and Washburn, describing dynamics of capillary imbibition [2, 3]. While it is generally appreciated that dynamics of fluid wetting processes are determined by the degree to which a system is out of capillary equilibrium, myriad complications exist that challenge the fundamental understanding of dynamic capillary phenomena. The topic has gathered much interest from recent Nobel laureate Pierre-Gilles de Gennes, who provided a seminal review of relevant dissipation mechanisms for fluid droplets spreading on solid surfaces [4] Although much about the dynamics of wetting has been revealed, much remains to be learned and intrinsic technological and fundamental interest in the topic drives continuing high levels of research activity. This is enabled partly by improved experimental capabilities for resolving wetting processes at increasingly finer temporal, spatial, and chemical resolution. Additionally, dynamic wetting research advances via higher fidelity computational modeling capabilities, which drive more highly refined theory development. The significance of this topic both fundamentally and technologically has resulted in a number of reviews of research activity in wetting dynamics. One recent example addresses the evaluation of existing wetting dynamics theories from an experimentalist's perspective [5]. A Current Opinion issue was recently dedicated to high temperature capillarity, including dynamics of high temperature spreading [6]. New educational tools have recently emerged for providing instruction in wetting

  4. Identifying overarching excipient properties towards an in-depth understanding of process and product performance for continuous twin-screw wet granulation. (United States)

    Willecke, N; Szepes, A; Wunderlich, M; Remon, J P; Vervaet, C; De Beer, T


    The overall objective of this work is to understand how excipient characteristics influence the process and product performance for a continuous twin-screw wet granulation process. The knowledge gained through this study is intended to be used for a Quality by Design (QbD)-based formulation design approach and formulation optimization. A total of 9 preferred fillers and 9 preferred binders were selected for this study. The selected fillers and binders were extensively characterized regarding their physico-chemical and solid state properties using 21 material characterization techniques. Subsequently, principal component analysis (PCA) was performed on the data sets of filler and binder characteristics in order to reduce the variety of single characteristics to a limited number of overarching properties. Four principal components (PC) explained 98.4% of the overall variability in the fillers data set, while three principal components explained 93.4% of the overall variability in the data set of binders. Both PCA models allowed in-depth evaluation of similarities and differences in the excipient properties. Copyright © 2017. Published by Elsevier B.V.

  5. In-Line Monitoring of a High-Shear Granulation Process Using the Baseline Shift of Near Infrared Spectra. (United States)

    Kuriyama, Atsushi; Osuga, Jin; Hattori, Yusuke; Otsuka, Makoto


    Although near infrared (NIR) spectra are primarily influenced by undesired variations, i.e., baseline shifts and non-linearity, and many applications of NIR spectroscopy to the real-time monitoring of wet granulation processes have been reported, the granulation mechanisms behind these variations have not been fully discussed. These variations of NIR spectra can be canceled out using appropriate pre-processing techniques prior to spectral analysis. The present study assessed the feasibility of directly using baseline shifts in NIR spectra to monitor granulation processes, because such shifts can reflect changes in the physical properties of the granular material, including particle size, shape, density, and refractive index. Specifically, OPUSGRAN ® , a novel granulation technology, was investigated by in-line NIR monitoring. NIR spectra were collected using a NIR diffuse reflectance fiber optic probe immersed in a high-shear granulator while simultaneously examining the morphology, particle size, density, strength, and Raman images of the mixture during granulation. The NIR baseline shift pattern was found to be characteristic of the OPUSGRAN ® technology and was attributed to variations in the light transmittance, reflection, and scattering resulting from changes in the physicochemical properties of the samples during granulation. The baseline shift also exhibited an inflection point around the completion of granulation, and therefore may be used to determine the endpoint of the process. These results suggest that a specific pattern of NIR baseline shifts are associated with the unique OPUSGRAN ® granulation mechanism and can be applied to monitor the manufacturing process and determine the endpoint.

  6. Synthesis of submicron silver powder from scrap low-temperature co-fired ceramic an e-waste: Understanding the leaching kinetics and wet chemistry. (United States)

    Swain, Basudev; Shin, Dongyoon; Joo, So Yeong; Ahn, Nak Kyoon; Lee, Chan Gi; Yoon, Jin-Ho


    The current study focuses on the understanding of leaching kinetics of metal in the LTCC in general and silver leaching in particular along with wet chemical reduction involving silver nanoparticle synthesis. Followed by metal leaching, the silver was selectively precipitated using HCl as AgCl. The precipitated AgCl was dissolved in ammonium hydroxide and reduced to pure silver metal nanopowder (NPs) using hydrazine as a reductant. Polyvinylpyrrolidone (PVP) used as a stabilizer and Polyethylene glycol (PEG) used as reducing reagent as well as stabilizing reagent to control size and shape of the Ag NPs. An in-depth investigation indicated a first-order kinetics model fits well with high accuracy among all possible models. Activation energy required for the first order reaction was 21.242 kJ mol -1 for Silver. PVP and PEG 1% each together provide better size control over silver nanoparticle synthesis using 0.4 M hydrazine as reductant, which provides relatively regular morphology in comparison to their individual application. The investigation revealed that the waste LTCC (an industrial e-waste) can be recycled through the reported process even in industrial scale. The novelty of reported recycling process is simplicity, versatile and eco-efficiency through which waste LTCC recycling can address various issues like; (i) industrial waste disposal (ii) synthesis of silver nanoparticles from waste LTCC (iii) circulate metal economy within a closed loop cycle in the industrial economies where resources are scarce, altogether. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. The effect of particle shape on mixing in a high shear mixer (United States)

    Sinnott, Matthew D.; Cleary, Paul W.


    Discrete element method modelling is used to study the effect of particle shape on the flow dynamics and mixing in a high shear mixer. The blade generates strong flow over its top surface while compacting and pushing forward particles that are directly in front of the blade. A complex three dimensional flow is established with vertical and radial flow components that are shape dependent and which control the nature of the mixing. Mixing was found to be fast in the azimuthal direction, of intermediate speed in the vertical direction and comparatively slow in the radial mixing. Diffusive mixing is characterised using the granular temperature which shows that the regions of higher granular temperature are larger for round particles than non-round ones leading to stronger diffusive mixing. The spatial distribution of the convective component of mixing is identified using novel calculation of shear strain rate. This size and shape of the high shear region is found to be only slightly sensitive to the particle shape indicating that the convective mixing is relatively independent of shape, except in the middle of the mixer. The blockiness of the particles has the strongest impact on flow and mixing while the mixing has only a weak dependence on the particle aspect ratio.

  8. High shear dispersion of tracers in polyolefins for improving their detection

    Directory of Open Access Journals (Sweden)

    Valérie Massardier


    Full Text Available Abstract An efficient recycling of end-of-life products is of crucial interest from an economical and ecological point of view. However, the near infrared spectroscopy often used for the optic sorting processes is limited because of the absorption of carbon black present in black plastics and as it only sorts as a function of chemical formulas. The tracing technology developed in this study is based on the dispersion of lanthanide complexes particles into polymers to give them a code that can be related to their formulation and viscosity that are important parameters for their re-processing. As the success of this technology is conditioned by achieving a fine dispersion of the tracer particles, we also focus on accomplishing a fine dispersion of tracer particles by using a high shear process. Processing under high shear rate (N= 800 rpm has proved to play a determining role in dispersing finely and homogenously tracer particles within PP matrix. Thanks to the good quality of dispersion, the detection of three tracers at a level of 0.1 wt% has been successfully achieved, even in black matrices for an acquisition time of 10 ms.

  9. Optimization of operating conditions in a high-shear mixer using dem model: determination of optimal fill level. (United States)

    Terashita, Keijiro; Nishimura, Takehiko; Natsuyama, Susumu


    For the purpose of evaluating optimal fill level of starting materials in a high-shear mixer, discrete element method (DEM) simulation was conducted to visualize kinetic status between particles. The simulation results obtained by changing fill levels were used to determine solid fraction of particles, particle velocity, particle velocity vector, and kinetic energy and discuss the flow pattern. Optimal fill level was obtained from the information on these matters. It was pointed out that understanding the kinetic energy between particles in an agitating vessel was effective in determining the optimal fill level. Granulation experiment was conducted to validate the optimal fill level obtained by the simulation, confirming the good agreement between these two results. It was pointed out that determination of kinetic energy between particles through the simulation was effective in obtaining an index of the kinetic status of particles. Further, it was confirmed that the simulation could provide more information than conventional granulation experiments could provide and also helpful in optimizing the operating conditions.

  10. Multivariate statistical modelling of the pharmaceutical process of wet granulation and tableting

    NARCIS (Netherlands)

    Westerhuis, Johannes Arnold


    Wet granulation in high-shear mixers is a process of particle size enlargement much used in the pharmaceutical industry to improve the tableting properties of powder mixtures, such as flowability and compactibility, necessary for the large scale production of pharmaceutical talbets. ... Zie: Summary

  11. Understanding and optimizing the dual excipient functionality of sodium lauryl sulfate in tablet formulation of poorly water soluble drug: wetting and lubrication. (United States)

    Aljaberi, Ahmad; Chatterji, Ashish; Dong, Zedong; Shah, Navnit H; Malick, Waseem; Singhal, Dharmendra; Sandhu, Harpreet K


    To evaluate and optimize sodium lauryl sulfate (SLS) and magnesium stearate (Mg.St) levels, with respect to dissolution and compaction, in a high dose, poorly soluble drug tablet formulation. A model poorly soluble drug was formulated using high shear aqueous granulation. A D-optimal design was used to evaluate and model the effect of granulation conditions, size of milling screen, SLS and Mg.St levels on tablet compaction and ejection. The compaction profiles were generated using a Presster(©) compaction simulator. Dissolution of the kernels was performed using a USP dissolution apparatus II and intrinsic dissolution was determined using a stationary disk system. Unlike kernels dissolution which failed to discriminate between tablets prepared with various SLS contents, the intrinsic dissolution rate showed that a SLS level of 0.57% was sufficient to achieve the required release profile while having minimal effect on compaction. The formulation factors that affect tablet compaction and ejection were identified and satisfactorily modeled. The design space of best factor setting to achieve optimal compaction and ejection properties was successfully constructed by RSM analysis. A systematic study design helped identify the critical factors and provided means to optimize the functionality of key excipient to design robust drug product.


    Fayed, Mohamed H; Abdel-Rahman, Sayed I; Alanazi, Fars K; Ahmed, Mahrous O; Tawfeek, Hesham M; Al-Shedfat, Ramadan I


    Application of quality by design (QbD) in high shear granulation process is critical and need to recognize the correlation between the granulation process parameters and the properties of intermediate (granules) and corresponding final product (tablets). The present work examined the influence of water amount (X,) and wet massing time (X2) as independent process variables on the critical quality attributes of granules and corresponding tablets using design of experiment (DoE) technique. A two factor, three level (32) full factorial design was performed; each of these variables was investigated at three levels to characterize their strength and interaction. The dried granules have been analyzed for their size distribution, density and flow pattern. Additionally, the produced tablets have been investigated for weight uniformity, crushing strength, friability and percent capping, disintegration time and drug dissolution. Statistically significant impact (p < 0.05) of water amount was identified for granule growth, percent fines and distribution width and flow behavior. Granule density and compressibility were found to be significantly influenced (p < 0.05) by the two operating conditions. Also, water amount has significant effect (p < 0.05) on tablet weight unifornity, friability and percent capping. Moreover, tablet disintegration time and drug dissolution appears to be significantly influenced (p < 0.05) by the two process variables. On the other hand, the relationship of process parameters with critical quality attributes of granule and final product tablet was identified and correlated. Ultimately, a judicious selection of process parameters in high shear granulation process will allow providing product of desirable quality.

  13. Integrated flow reactor that combines high-shear mixing and microwave irradiation for biodiesel production

    International Nuclear Information System (INIS)

    Choedkiatsakul, I.; Ngaosuwan, K.; Assabumrungrat, S.; Tabasso, S.; Cravotto, G.


    A new simple flow system which is made up of a multi-rotor high-shear mixer connected to a multimode microwave reactor has been assembled. This simple loop reactor has been successfully used in the NaOH-catalyzed transesterification of refined palm oil in methanol. Thanks to optimal mass/heat transfer, full conversion was achieved within 5 min (biodiesel yield of 99.80%). High-quality biodiesel was obtained that is in accordance with international specifications and analytical ASTM standards. The procedure's high efficiency and low energy consumption should pave the way for process scale up. - Highlights: • The combination of HSM-MW flow system for biodiesel production has been proposed. • Highly efficient mass and heat transfer in transesterification reaction. • The hybrid reactor enables a complete conversion in 5 min reaction time. • The new system halved the energy consumption of conventional processes


    Ali, Bahaa E; Al-Shedfat, Ramadan I; Fayed, Mohamed H; Alanazi, Fars K


    Development of orodispersible delivery system of high mechanical properties and low disintegration time is a big challenge. The aim of the current work was to assess and optimize the high shear granulation process as a new methodology for development of orodispersible tablets of high quality attributes using design of experiment approach. A two factor, three levels (32), full factorial design was carried out to investigate the main and interaction effects of independent variables, water amount (XI) and granulation time (X2) on the characteristics of granules and final product, tablet. The produced granules were analyzed for their granule size, density and flowability. Furthermore, the produced tablets were tested for: weight variation, breaking force/ crushing strength, friability, disintegration time and drug dissolution. Regression analysis results of multiple linear models showed a high correlation between the adjusted R-squared and predicted R-squared for all granules and tablets characteristics, the difference is less than 0.2. All dependent responses of granules and tablets were found to be impacted significantly (p granules and tablet characteristics as shown by higher its coefficient estimate for all selected responses. Numerical optimization using desirability function was performed to optimize the variables under study to provide orodispersible system within the USP limit with respect of mechanical properties and disintegration time. It was found that the higher desirability (0.915) could be attained at the low level pf water (180 g) and short granulation time (1.65 min). Eventually, this study provides the formulator with helpful information in selecting the proper level of water and granulation time to provide an orodispersible system of high crushing strength and very low disintegration time, when high shear granulation methodology was used as a method of manufacture.

  15. Two-dimensional strain-hardening membrane model for large deformation behavior of multiple red blood cells in high shear conditions. (United States)

    Ye, Swe Soe; Ng, Yan Cheng; Tan, Justin; Leo, Hwa Liang; Kim, Sangho


    Computational modeling of Red Blood Cell (RBC) flow contributes to the fundamental understanding of microhemodynamics and microcirculation. In order to construct theoretical RBC models, experimental studies on single RBC mechanics have presented a material description for RBC membranes based on their membrane shear, bending and area moduli. These properties have been directly employed in 3D continuum models of RBCs but practical flow analysis with 3D models have been limited by their computationally expensive nature. As such, various researchers have employed 2D models to efficiently and qualitatively study microvessel flows. Currently, the representation of RBC dynamics using 2D models is a limited methodology that breaks down at high shear rates due to excessive and unrealistic stretching. We propose a localized scaling of the 2D elastic moduli such that it increases with RBC local membrane strain, thereby accounting for effects such as the Poisson effect and membrane local area incompressibility lost in the 2D simplification. Validation of our 2D Large Deformation (2D-LD) RBC model was achieved by comparing the predicted RBC deformation against the 3D model from literature for the case of a single RBC in simple shear flow under various shear rates (dimensionless shear rate G = 0.05, 0.1, 0.2, 0.5). The multi-cell flow of RBCs (38% Hematocrit) in a 20 μm width microchannel under varying shear rates (50, 150, 150 s-1) was then simulated with our proposed model and the popularly-employed 2D neo-Hookean model in order to evaluate the efficacy of our proposed 2D-LD model. The validation set indicated similar RBC deformation for both the 2D-LD and the 3D models across the studied shear rates, highlighting the robustness of our model. The multi-cell simulation indicated that the 2D neo-Hookean model predicts noodle-like RBC shapes at high shear rates (G = 0.5) whereas our 2D-LD model maintains sensible RBC deformations. The ability of the 2D-LD model to

  16. Wetting 101 degrees. (United States)

    Gao, Lichao; McCarthy, Thomas J


    We review our 2006-2009 publications on wetting and superhydrophobicity in a manner designed to serve as a useful primer for those who would like to use the concepts of this field. We demonstrate that the 1D (three-phase, solid/liquid/vapor) contact line perspective is simpler, more intuitive, more useful, and more consistent with facts than the disproved but widely held-to-be-correct 2D view. We give an explanation of what we believe to be the reason that the existing theoretical understanding is wrong and argue that the teaching of surface science over the last century has led generations of students and scientists to a misunderstanding of the wetting of solids by liquids. We review our analyses of the phenomena of contact angle hysteresis, the lotus effect, and perfect hydrophobicity and suggest that needlessly complex theoretical understandings, incorrect models, and ill-defined terminology are not useful and can be destructive.

  17. Improvement of enalapril maleate chemical stability by high shear melting granulation. (United States)

    de Oliveira, Ana Paula Montandon; Cunha, Talita Amorim; Serpa, Raphael Caixeta; Taveira, Stephânia Fleury; Lima, Eliana Martins; Almeida Diniz, Danielle Guimarães; de Freitas, Luis Alexandre Pedro; Marreto, Ricardo Neves


    Abstract Enalapril maleate is a widely used drug, which is chemically unstable when mixed with excipients resulting in enalaprilat and diketopiperazine as the main degradation products. The preparation of enalapril sodium salt has been used to improve drug stability in solid dosage forms; however, product rejection is observed when the chemical reaction for obtaining the sodium salt is not completely finished before packaging. In this study, granules were prepared by melting granulation using stearic acid or glyceryl monostearate, with a view to developing more stable enalapril maleate solid dosage forms. The granules were prepared in a laboratory-scale high shear mixer and compressed in a rotary machine. Size distribution, flow properties, in vitro drug release and enalapril maleate chemical stability were evaluated and compared with data obtained from tablets prepared without hydrophobic binders. All formulations showed good physical properties and immediate drug release. The greatest improvement in the enalapril maleate stability was observed in formulations containing stearic acid. This study showed that hot melting granulation could be successfully used to prepare enalapril maleate granules which could substitute the in situ formation of enalapril sodium salt, since they provided better enalapril stability in solid dosage forms.

  18. Optimization of {beta}-carotene loaded solid lipid nanoparticles preparation using a high shear homogenization technique

    Energy Technology Data Exchange (ETDEWEB)

    Triplett, Michael D., E-mail: triplettm@battelle.or [Battelle Memorial Institute, Health and Life Sciences Global Business (United States); Rathman, James F. [The Ohio State University, Department of Chemical and Biomolecular Engineering (United States)


    Using statistical experimental design methodologies, the solid lipid nanoparticle design space was found to be more robust than previously shown in literature. Formulation and high shear homogenization process effects on solid lipid nanoparticle size distribution, stability, drug loading, and drug release have been investigated. Experimentation indicated stearic acid as the optimal lipid, sodium taurocholate as the optimal cosurfactant, an optimum lecithin to sodium taurocholate ratio of 3:1, and an inverse relationship between mixing time and speed and nanoparticle size and polydispersity. Having defined the base solid lipid nanoparticle system, {beta}-carotene was incorporated into stearic acid nanoparticles to investigate the effects of introducing a drug into the base solid lipid nanoparticle system. The presence of {beta}-carotene produced a significant effect on the optimal formulation and process conditions, but the design space was found to be robust enough to accommodate the drug. {beta}-Carotene entrapment efficiency averaged 40%. {beta}-Carotene was retained in the nanoparticles for 1 month. As demonstrated herein, solid lipid nanoparticle technology can be sufficiently robust from a design standpoint to become commercially viable.

  19. Optimization of β-carotene loaded solid lipid nanoparticles preparation using a high shear homogenization technique

    International Nuclear Information System (INIS)

    Triplett, Michael D.; Rathman, James F.


    Using statistical experimental design methodologies, the solid lipid nanoparticle design space was found to be more robust than previously shown in literature. Formulation and high shear homogenization process effects on solid lipid nanoparticle size distribution, stability, drug loading, and drug release have been investigated. Experimentation indicated stearic acid as the optimal lipid, sodium taurocholate as the optimal cosurfactant, an optimum lecithin to sodium taurocholate ratio of 3:1, and an inverse relationship between mixing time and speed and nanoparticle size and polydispersity. Having defined the base solid lipid nanoparticle system, β-carotene was incorporated into stearic acid nanoparticles to investigate the effects of introducing a drug into the base solid lipid nanoparticle system. The presence of β-carotene produced a significant effect on the optimal formulation and process conditions, but the design space was found to be robust enough to accommodate the drug. β-Carotene entrapment efficiency averaged 40%. β-Carotene was retained in the nanoparticles for 1 month. As demonstrated herein, solid lipid nanoparticle technology can be sufficiently robust from a design standpoint to become commercially viable.

  20. Use of in-line near-infrared spectroscopy in combination with chemometrics for improved understanding of pharmaceutical processes

    DEFF Research Database (Denmark)

    Rantanen, Jukka; Wikström, Håkan; Turner, Rebecca


    was extracted. Principal component loadings were fully interpreted to validate the conclusions drawn from scores and predictions. Thus NIR spectroscopy could be used to determine the end points of the three subphases of high shear wet granulation and, as such, provide a fast in-line quality control tool....... solid dosage form. In this study, the use of in-line near-infrared (NIR) spectroscopy as a process analytical tool for high shear granulation was investigated. In combination with principal component-based methods, process analysis of three separate phases of high shear wet granulation (mixing, spraying...

  1. The paradox of high shear granulation : the formation of non-homogeneous granules

    NARCIS (Netherlands)

    Dries, Kaspar van den


    Wet granulation is a process used for the particle size enlargement of primary powders. The mixing of a liquid with the powder glues the primary particles together, which results in the formation of the granules. The mixing action can be performed in many ways, like tumbling (drum granulation),


    Fayed, Mohamed H; Abdel-Rahman, Sayed I; Alanazi, Fars K; Ahmed, Mahrous O; Tawfeek, Hesham M; Ali, Bahaa E


    High shear wet granulation is a significant component procedure in the pharmaceutical industry. The objective of the study was to investigate the influence of two independent formulation variables; polyvinypyrrolidone (PVP) as a binder (X,) and croscarmellose sodium (CCS) as a disintegrant (X2) on the crit- ical quality attributes of acetaminophen granules and their corresponding tablets using design of experiment (DoE) approach. A two factor, three level (32) full factorial design has been applied; each variable was investi- gated at three levels to characterize their strength and interaction. The dried granules have been analyzed for their density, granule size and flowability. Additionally, the produced tablets have been investigated for: break- ing force, friability, disintegration time and t. of drug dissolution. The analysis of variance (ANOVA) showed that the two variables had a significant impact (p < 0.05) on granules and tablets characteristics, while only the binder concentration influenced the tablets friability. Furthermore, significant interactions (p < 0.05) between the two variables, for granules and tablets attributes, were also found. However, variables interaction showed minimal effect for granules flowability as well as tablets friability. Desirability function was carried out to opti- mize the variables under study to obtain product within the USP limit. It was found that the higher desirability (0.985) could be obtained at the medium level of PVP and low level of CCS. Ultimately, this study supplies the formulator with beneficial tools in selecting the proper level of binder and disintegrant to attain product with desired characteristics.

  3. Role of red blood cells in the anemia-associated bleeding under high shear conditions. (United States)

    Yaoi, H; Shida, Y; Ogiwara, K; Hosokawa, K; Shima, M; Nogami, K


    Red blood cells (RBCs) contribute to hemostasis under blood-flow, and anemia might contribute to a hemorrhagic diathesis. The majority of current laboratory techniques to assess hemostasis do not consider the effects of RBCs. An assay to determine the role of RBCs in hemostasis could be beneficial for clinical management. To investigate the influence of RBCs in hemostasis. Hemostasis was investigated using a novel microchip flow-chamber system (T-TAS ® ) in an anemic patient with von Willebrand disease. Subsequently, the effects of RBCs in total thrombus analysis system (T-TAS) were examined using reconstituted whole blood at various hematocrit levels. In vivo: When the patient was anemic and demonstrated persisted hemorrhagic symptoms despite the maintained adequate von Willebrand factor ristocetin cofactor activity levels, thrombus formation determined by T-TAS was delayed. However, transfusions of RBCs resolved bleeding symptom and, accordingly, the thrombus formation in T-TAS improved. In vitro: Thrombus formation determined by T-TAS at 1000 s -1 was dose-dependent on hematocrit (the time to reach 10 kPa (T 10 ): 10.0 ± 0, 9.5 ± 1.4, 6.7 ± 2.4, 2.8 ± 1.6 min at hematocrits of 0%, 12.5%, 25% and 50%, respectively). Markedly defective thrombus formation (T 10 >10 min) was confirmed at a hematocrit <25% at 2000 s -1 . Red blood cells play an essential role in hemostasis under high shear, and RBC transfusions could be effective for refractory bleeding in patients with anemia. T-TAS measurements appear to reflect the hemostatic consequences of diminished red cell numbers under blood-flow, and could provide a valuable means for monitoring patients. © 2017 John Wiley & Sons Ltd.

  4. Effect of high shear mixing parameters and degassing temperature on the morphology of epoxy-clay nanocomposites

    KAUST Repository

    Al-Qadhi, Muneer


    Epoxy-clay nanocomposites were prepared by high shear mixing method using Nanomer I.30E nanoclay as nano-reinforcement in diglycidyl ether of bisphenol A (DGEBA). The effect of mixing speed and time on the nature and degree of clay dispersion were investigated by varying the mixing speed in the range of 500-8000 RPM and mixing time in the range of 15-90 minutes. The effect of degassing temperature on the morphology of the resultant nanocomposites was also studied. Scanning and transmission microscopy (SEM and TEM) along with x-ray diffraction (XRD) have been used to characterize the effect of shear mixing speed, mixing time and degassing temperature on the structure of the resultant nanocomposites. The SEM, TEM and XRD examinations demonstrated that the degree of clay dispersion was improved with increasing the high shear mixing speed and mixing time. The results showed that the optimum high shear mixing speed and mixing time were 6000 rpm and 60 min, respectively. It was observed that the structure of the nanocomposites that have been degassed at 65°C was dominated by ordered intercalated morphology while disordered intercalated with some exfoliated morphology was found for the sample degassed at 100°C for the first 2 hours of the degassing process. © (2013) Trans Tech Publications, Switzerland.

  5. Modeled Wet Nitrate Deposition (United States)

    U.S. Environmental Protection Agency — Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface...

  6. Quality by Design (QbD) approach to optimize the formulation of a bilayer combination tablet (Telmiduo®) manufactured via high shear wet granulation. (United States)

    Lee, Ah Ram; Kwon, Seok Young; Choi, Du Hyung; Park, Eun Seok


    A bilayer tablet, which consisted of telmisartan and amlodipine besylate, was formulated based on a Quality by Design (QbD) approach. The control and response factors were determined based on primary knowledge and the target values of the control tablet (Twynsta ® ). A D-optimal mixture design was used to obtain the optimal formulations in terms of D-mannitol, crospovidone, and MCC for the telmisartan layer, and CCM-Na, PVP K25, and Prosolv for the amlodipine layer. The quantitative effects of the different formulation factors on the response factors were accurately predicted using the equations of best fit and a strong linearity was observed between the predicted and actual values of the response factors. The optimized bilayer tablet was obtained using a numeric optimization technique and was characterized compared with a control (Twynsta ® ) by using various physical evaluations and in vivo pharmacokinetic parameters. The physical stability of Telmiduo ® was greater than that of Twynsta ® owing to the improvement of formulation factors. The in vivo pharmacokinetic parameters suggested that Telmiduo ® might have pharmaceutical equivalence and bioequivalence with Twynsta ® . Therefore, the bilayer tablet that consisted of telmisartan and amlodipine besylate could be produced using a more economical and simpler method than that used to produce Twynsta ® . Moreover, the suitability of QbD for effective product development in the pharmaceutical industry was shown. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Mixing of low-dose cohesive drug and overcoming of pre-blending step using a new gentle-wing high shear mixer granulator. (United States)

    Alsulays, Bader B; Fayed, Mohamed H; Alalaiwe, Ahmed; Alshahrani, Saad M; Alshetaili, Abdullah S; Alshehri, Sultan M; Alanazi, Fars K


    The objective of this study was to examine the influence of drug amount and mixing time on the homogeneity and content uniformity of a low-dose drug formulation during the dry mixing step using a new gentle-wing high shear mixer. Moreover, the study investigated the influence of drug incorporation mode on the content uniformity of tablets manufactured by different methods. Albuterol sulphate was selected as a model drug and was blended with the other excipients at two different levels, 1% w/w and 5% w/w at impeller speed of 300 rpm and chopper speed of 3000 rpm up to 30 minutes. Utilizing a 1 ml unit side-sampling thief probe, triplicate samples were taken from 9 different positions in the mixer bowl at selected time points. Two methods were used for manufacturing of tablets, direct compression and wet granulation. The produced tablets were sampled at the beginning, middle, and end of the compression cycle. An ANOVA analysis indicated the significant effect (P drug amount on the content uniformity of the powder blend and the corresponding tablets. For 1% w/w and 5% w/w formulations, incorporation of the drug in the granulating fluid provided tablets with excellent content uniformity and very low RSD (∼ 0.61%) during the whole tableting cycle compared to direct compression and granulation method with dry incorporation mode of the drug. Overall, gentle-wing mixer is a good candidate for mixing of low dose cohesive drug and provide tablets with acceptable content uniformity with no need for pre-blending step.

  8. Haptic perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kosters, N.D.; Daanen, H.A.M.; Kappers, A.M.L.


    The sensation of wetness is well-known but barely investigated. There are no specific wetness receptors in the skin, but the sensation is mediated by temperature and pressure perception. In our study, we have measured discrimination thresholds for the haptic perception of wetness of three di erent

  9. Sense Things in the Big Deep Water Bring the Big Deep Water to Computers so People can understand the Deep Water all the Time without getting wet (United States)

    Pelz, M.; Heesemann, M.; Scherwath, M.; Owens, D.; Hoeberechts, M.; Moran, K.


    Senses help us learn stuff about the world. We put sense things in, over, and under the water to help people understand water, ice, rocks, life and changes over time out there in the big water. Sense things are like our eyes and ears. We can use them to look up and down, right and left all of the time. We can also use them on top of or near the water to see wind and waves. As the water gets deep, we can use our sense things to see many a layer of different water that make up the big water. On the big water we watch ice grow and then go away again. We think our sense things will help us know if this is different from normal, because it could be bad for people soon if it is not normal. Our sense things let us hear big water animals talking low (but sometimes high). We can also see animals that live at the bottom of the big water and we take lots of pictures of them. Lots of the animals we see are soft and small or hard and small, but sometimes the really big ones are seen too. We also use our sense things on the bottom and sometimes feel the ground shaking. Sometimes, we get little pockets of bad smelling air going up, too. In other areas of the bottom, we feel hot hot water coming out of the rock making new rocks and we watch some animals even make houses and food out of the hot hot water that turns to rock as it cools. To take care of the sense things we use and control water cars and smaller water cars that can dive deep in the water away from the bigger water car. We like to put new things in the water and take things out of the water that need to be fixed at least once a year. Sense things are very cool because you can use the sense things with your computer too. We share everything for free on our computers, which your computer talks to and gets pictures and sounds for you. Sharing the facts from the sense things is the best part about having the sense things because we can get many new ideas about understanding the big water from anyone with a computer!

  10. Melt pelletization of a hygroscopic drug in a high shear mixer. Part 3. Effects of binder variation. (United States)

    Thies, R; Kleinebudde, P


    Melt pelletization experiments with sodium valproate as a hygroscopic drug were performed in a laboratory scale high shear mixer. In the current part, the effect of altering the binder liquid properties (using different binders, varying the temperature, or adding highly dispersed silicon dioxide to the molten binder) on the pellet size, size distribution and the growth rate was studied. Three meltable binders, namely glycerol monostearate (GMS), hydrated castor oil (HCO), and polyethylene glycol (PEG), were included in the study. Two series of experiments with GMS or HCO showed a higher granule growth rate with decreasing binder viscosity. Also, increases in the granule growth rate were observed for all meltable binders tested, when the binder amount and the impeller speed were increased. Factorial designs with all three binders were performed under the same conditions. In these experiments, no correlation existed between the granule growth rate and the viscosity of the different binders. The different granule growth rate, however, was mainly attributed to the different solubility of sodium valproate in the binder liquid used. Higher solubility increased the volume of the binder liquid and, accordingly, the granule growth rate. Taking the amount of dissolved drug into account, the granule growth rates of GMS and PEG were comparable. However, HCO displayed a lower granule growth rate, which might be related to its low adhesion tension. During melt pelletization in a high shear mixer the solubility of the drug in the molten binder strongly influences the pelletization process.

  11. Effects of physical properties of powder particles on binder liquid requirement and agglomerate growth mechanisms in a high shear mixer. (United States)

    Johansen, A; Schaefer, T


    A study was performed in order to elucidate the effects of the physical properties of small powder particles on binder liquid requirement and agglomerate growth mechanisms. Three grades of calcium carbonate having different particle size distribution, surface area, and particle shape but approximately the same median particle size (4-5 microm), were melt agglomerated with polyethylene glycol (PEG) 3000 or 20,000 in an 8-l high shear mixer at three impeller speeds. The binder liquid requirement was found to be very dependent on the packing properties of the powder, a denser packing resulting in a lower binder liquid requirement. The densification of the agglomerates in the high shear mixer could be approximately predicted by compressing a powder sample in a compaction simulator. With the PEG having the highest viscosity (PEG 20,000), the agglomerate formation and growth occurred primarily by the immersion mechanism, whereas PEG 3000 gave rise to agglomerate growth by coalescence. Powder particles with a rounded shape and a narrow size distribution resulted in breakage of agglomerates with PEG 3000, whereas no breakage was seen with PEG 20,000. Powder particles having an irregular shape and surface structure could be agglomerated with PEG 20,000, whereas agglomerate growth became uncontrollable with PEG 3000. When PEG 20,000 was added as a powder instead of flakes, the resultant agglomerates became rounder and the size distribution narrower.

  12. Defined wetting properties of optical surfaces (United States)

    Felde, Nadja; Coriand, Luisa; Schröder, Sven; Duparré, Angela; Tünnermann, Andreas


    Optical surfaces equipped with specific functional properties have attracted increasing importance over the last decades. In the light of cost reduction, hydrophobic self-cleaning behavior is aspired. On the other side, hydrophilic properties are interesting due to their anti-fog effect. It has become well known that such wetting states are significantly affected by the surface morphology. For optical surfaces, however, this fact poses a problem, as surface roughness can induce light scattering. The generation of optical surfaces with specific wetting properties, hence, requires a profound understanding of the relation between the wetting and the structural surface properties. Thus, our work concentrates on a reliable acquisition of roughness data over a wide spatial frequency range as well as on the comprehensive description of the wetting states, which is needed for the establishment of such correlations. We will present our advanced wetting analysis for nanorough optical surfaces, extended by a vibration-based procedure, which is mainly for understanding and tailoring the wetting behavior of various solid-liquid systems in research and industry. Utilizing the relationships between surface roughness and wetting, it will be demonstrated how different wetting states for hydrophobicity and hydrophilicity can be realized on optical surfaces with minimized scatter losses.

  13. Wet oxidation of quinoline

    DEFF Research Database (Denmark)

    Thomsen, A.B.; Kilen, H.H.


    The influence of oxygen pressure (0.4 and 2 MPa). reaction time (30 and 60 min) and temperature (260 and 280 degrees C) on the wet oxidation of quinoline has been studied. The dominant parameters for the decomposition of quinoline were oxygen pressure and reaction temperature. whereas the reaction...... time was less important within the range studied. Nitrifying bacteria were used to measure the inhibition from wet oxidative-treated samples to study the effect of the (wet oxidation) reaction conditions. Wet oxidation made quinoline more toxic to Nitrosomonas. This was observed for Nitrobacter as well....... The combined wet oxidation and biological treatment of reaction products resulted in 91% oxidation of the parent compound to CO2 and water. Following combined wet oxidation and biological treatment the sample showed low toxicity towards Nitrosomonas and no toxicity towards Nitrobacter. (C) 1998 Elsevier...

  14. PREFACE: Wetting: introductory note (United States)

    Herminghaus, S.


    The discovery of wetting as a topic of physical science dates back two hundred years, to one of the many achievements of the eminent British scholar Thomas Young. He suggested a simple equation relating the contact angle between a liquid surface and a solid substrate to the interfacial tensions involved [1], γlg cos θ = γsg - γsl (1) In modern terms, γ denotes the excess free energy per unit area of the interface indicated by its indices, with l, g and s corresponding to the liquid, gas and solid, respectively [2]. After that, wetting seems to have been largely ignored by physicists for a long time. The discovery by Gabriel Lippmann that θ may be tuned over a wide range by electrochemical means [3], and some important papers about modifications of equation~(1) due to substrate inhomogeneities [4,5] are among the rare exceptions. This changed completely during the seventies, when condensed matter physics had become enthusiastic about critical phenomena, and was vividly inspired by the development of the renormalization group by Kenneth Wilson [6]. This had solved the long standing problem of how to treat fluctuations, and to understand the universal values of bulk critical exponents. By inspection of the critical exponents of the quantities involved in equation~(1), John W Cahn discovered what he called critical point wetting: for any liquid, there should be a well-defined transition to complete wetting (i.e., θ = 0) as the critical point of the liquid is approached along the coexistence curve [7]. His paper inspired an enormous amount of further work, and may be legitimately viewed as the entrance of wetting into the realm of modern physics. Most of the publications directly following Cahn's work were theoretical papers which elaborated on wetting in relation to critical phenomena. A vast amount of interesting, and in part quite unexpected, ramifications were discovered, such as the breakdown of universality in thin film systems [8]. Simultaneously, a number

  15. Process analytical technology (PAT) approach to the formulation of thermosensitive protein-loaded pellets: Multi-point monitoring of temperature in a high-shear pelletization. (United States)

    Kristó, Katalin; Kovács, Orsolya; Kelemen, András; Lajkó, Ferenc; Klivényi, Gábor; Jancsik, Béla; Pintye-Hódi, Klára; Regdon, Géza


    In the literature there are some publications about the effect of impeller and chopper speeds on product parameters. However, there is no information about the effect of temperature. Therefore our main aim was the investigation of elevated temperature and temperature distribution during pelletization in a high shear granulator according to process analytical technology. During our experimental work, pellets containing pepsin were formulated with a high-shear granulator. A specially designed chamber (Opulus Ltd.) was used for pelletization. This chamber contained four PyroButton-TH® sensors built in the wall and three PyroDiff® sensors 1, 2 and 3cm from the wall. The sensors were located in three different heights. The impeller and chopper speeds were set on the basis of 3 2 factorial design. The temperature was measured continuously in 7 different points during pelletization and the results were compared with the temperature values measured by the thermal sensor of the high-shear granulator. The optimization parameters were enzyme activity, average size, breaking hardness, surface free energy and aspect ratio. One of the novelties was the application of the specially designed chamber (Opulus Ltd.) for monitoring the temperature continuously in 7 different points during high-shear granulation. The other novelty of this study was the evaluation of the effect of temperature on the properties of pellets containing protein during high-shear pelletization. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Wet granular matter a truly complex fluid

    CERN Document Server

    Herminghaus, Stephan


    This is a monograph written for the young and advanced researcher who is entering the field of wet granular matter and keen to understand the basic physical principles governing this state of soft matter. It treats wet granulates as an instance of a ternary system, consisting of the grains, a primary, and a secondary fluid. After addressing wetting phenomena in general and outlining the basic facts on dry granular systems, a chapter on basic mechanisms and their effects is dedicated to every region of the ternary phase diagram. Effects of grain shape and roughness are considered as well. Rather than addressing engineering aspects such as existing books on this topic do, the book aims to provide a generalized framework suitable for those who want to understand these systems on a more fundamental basis. Readership: For the young and advanced researcher entering the field of wet granular matter.

  17. Evaluatie Wet openbare manifestaties

    NARCIS (Netherlands)

    Roorda, Berend; Brouwer, Jan; Schilder, A.E.


    Het rapport betreft een uitgebreide evaluatie van de Wet openbare manifestaties (Wom) in opdracht van het Ministerie van Binnenlandse Zaken en Koninkrijksrelaties. Op grond van onderzoek naar de parlementaire geschiedenis van de Wom, de literatuur, de jurisprudentie, gesprekken met beleidsadviseurs

  18. Enuresis (Bed-Wetting) (United States)

    ... Symptoms of enuresis Enuresis is when an older child (age 7 or older) wets the bed at night ... feel guilt and embarrassment. It’s true that your child should take responsibility for bedwetting. He or she could do this ...

  19. Comparison of torque measurements and near-infrared spectroscopy in characterization of a wet granulation process

    DEFF Research Database (Denmark)

    Jørgensen, Anna Cecilia; Luukkonen, Pirjo; Rantanen, Jukka


    The purpose of this study was to compare impeller torque measurements and near-infrared (NIR) spectroscopy in the characterization of the water addition phase of a wet granulation process. Additionally, the effect of hydrate formation during granulation on the impeller torque was investigated....... Anhydrous theophylline, alpha-lactose monohydrate, and microcrystalline cellulose (MCC) were used as materials for the study. The materials and mixtures of them were granulated using purified water in a small-scale high-shear mixer. The impeller torque was registered and NIR spectra of wet samples were...... recorded at-line. The torque and the NIR baseline-corrected water absorbances increased with increasing water content. A plateau in the NIR baseline-corrected water absorbances was observed for wet masses containing MCC. This was at the region of optimal water amount for granulation according to the torque...

  20. Multi-channel analysis of surface waves MASW of models with high shear-wave velocity contrast (United States)

    Ivanov, J.; Miller, R.D.; Peterie, S.; Zeng, C.; Xia, J.; Schwenk, T.


    We use the multi-channel analysis of surface waves MASW method to analyze synthetic seismic data calculated using models with high shear-wave velocity Vs contrast. The MASW dispersion-curve images of the Rayleigh wave are obtained using various sets of source-offset and spread-size configurations from the synthetic seismic data and compared with the theoretically calculated fundamental- and higher-mode dispersion-curves. Such tests showed that most of the dispersion-curve images are dominated by higher-mode energy at the low frequencies, especially when analyzing data from long receiver offsets and thus significantly divert from numerically expected dispersion-curve trends, which can lead to significant Vs overestimation. Further analysis showed that using data with relatively short spread lengths and source offsets can image the desired fundamental-mode of the Rayleigh wave that matches the numerically expected dispersion-curve pattern. As a result, it was concluded that it might be possible to avoid higher-mode contamination at low frequencies at sites with high Vs contrast by appropriate selection of spread size and seismic source offset. ?? 2011 Society of Exploration Geophysicists.

  1. Melt pelletization in high shear mixer using a hydrophobic melt binder: influence of some apparatus and process variables. (United States)

    Voinovich, D; Moneghini, M; Perissutti, B; Franceschinis, E


    The effects of process conditions and the apparatus variables on the granulometric characteristics of a formulation containing a hydrophobic binder (stearic acid), lactose and paracetamol prepared by melt pelletization process were investigated in a 10-litre high shear mixer. The factors under investigation were: impeller speed, massing time, type of impeller blades and presence of the deflector and their reciprocal interactions. Two granule characteristics were analysed: the percentage of aggregates larger than 3000 microm (Y(1)) and the yield of the 2000-microm pellet size fraction (Y(2)). In order to estimate simultaneously the above-mentioned factors, a particular experimental design was adopted, that allowed the reduction of the number of trials from 378 to 35 and took into consideration other uncontrolled factors with the aid of a block variable. Using the postulated model, we found the optimal operating conditions to minimize Y(1) and increase Y(2) by selecting the type of impeller, and by using an impeller speed lower than 300 rpm, a massing time of 8-9 min and by not using the deflector. Finally, the validity of the adopted strategy has been proved with an additional check point.

  2. Nitrogen-Doped Carbon Nanoparticles for Oxygen Reduction Prepared via a Crushing Method Involving a High Shear Mixer

    Directory of Open Access Journals (Sweden)

    Lei Shi


    Full Text Available The disposal of agricultural wastes such as fresh banana peels (BPs is an environmental issue. In this work, fresh BPs were successfully transformed into nitrogen-doped carbon nanoparticles (N-CNPs by using a high shear mixer facilitated crushing method (HSM-FCM followed by carbonization under Ar atmosphere. Ammonia-activated N-CNPs (N-CNPs-NH3 were prepared via subsequent ammonia activation treatments at a high temperature. The as-prepared N-CNPs and N-CNPs-NH3 materials both exhibited high surface areas (above 700 m2/g and mean particle size of 50 nm. N-CNPs-NH3 showed a relatively higher content of pyridinic and graphitic N compared to N-CNPs. In alkaline media, N-CNPs-NH3 showed superior performances as an oxygen reduction reaction (ORR catalyst (E0 = −0.033 V, J = 2.4 mA/cm2 compared to N-CNPs (E0 = 0.07 V, J = 1.8 mA/cm2. In addition, N-CNPs-NH3 showed greater oxygen reduction stability and superior methanol crossover avoidance than a conventional Pt/C catalyst. This study provides a novel, simple, and scalable approach to valorize biomass wastes by synthesizing highly efficient electrochemical ORR catalysts.

  3. Effects of interactions between powder particle size and binder viscosity on agglomerate growth mechanisms in a high shear mixer. (United States)

    Johansen, A; Schaefer, T


    A study was performed in order to elucidate the effects of the interactions between powder particle size and binder viscosity on the mechanisms involved in agglomerate formation and growth. Calcium carbonates having mean particle sizes in the range of 5-214 microm and polyethylene glycols having viscosities in the range of approximately 50-100000 mPas were melt agglomerated in a high shear mixer. Agglomerate growth by nucleation and coalescence was found to dominate when agglomerating small powder particles and binders with a low viscosity. Increasing the binder viscosity increased the formation of agglomerates by immersion of powder particles in the surface of the binder droplets. With a larger powder particle size, an increasing binder viscosity was necessary in order to obtain an agglomerate strength being sufficient to avoid breakage. Due to a low agglomerate strength, a satisfying agglomeration of very large particles (214 microm) could not be obtained, even with very viscous binders. The study demonstrated that the optimum agglomerate growth occurred when the agglomerates were of an intermediate strength causing an intermediate deformability of the agglomerates. In order to produce spherical agglomerates (pellets), a low viscosity binder has to be chosen when agglomerating a powder with a small particle size, and a high viscosity binder must be applied in agglomeration of powders with large particles.

  4. The effect of the amount of binder liquid on the granulation mechanisms and structure of microcrystalline cellulose granules prepared by high shear granulation

    NARCIS (Netherlands)

    Bouwman, A M; Henstra, M J; Westerman, D; Chung, J T; Zhang, Z; Ingram, A; Seville, J P K; Frijlink, H W


    The structure of granules changes during the high shear granulation process. The purpose of this research was to investigate the effect of the amount of binder liquid on the structure of the granules and the structural changes which occur during the granulation process, using microcrystalline

  5. Effects of Coating Materials and Processing Conditions on Flow Enhancement of Cohesive Acetaminophen Powders by High-Shear Processing With Pharmaceutical Lubricants. (United States)

    Wei, Guoguang; Mangal, Sharad; Denman, John; Gengenbach, Thomas; Lee Bonar, Kevin; Khan, Rubayat I; Qu, Li; Li, Tonglei; Zhou, Qi Tony


    This study has investigated the surface coating efficiency and powder flow improvement of a model cohesive acetaminophen powder by high-shear processing with pharmaceutical lubricants through 2 common equipment, conical comil and high-shear mixer. Effects of coating materials and processing parameters on powder flow and surface coating coverage were evaluated. Both Carr's index and shear cell data indicated that processing with the lubricants using comil or high-shear mixer substantially improved the flow of the cohesive acetaminophen powder. Flow improvement was most pronounced for those processed with 1% wt/wt magnesium stearate, from "cohesive" for the V-blended sample to "easy flowing" for the optimally coated sample. Qualitative and quantitative characterizations demonstrated a greater degree of surface coverage for high-shear mixing compared with comilling; nevertheless, flow properties of the samples at the corresponding optimized conditions were comparable between 2 techniques. Scanning electron microscopy images demonstrated different coating mechanisms with magnesium stearate or l-leucine (magnesium stearate forms a coating layer and leucine coating increases surface roughness). Furthermore, surface coating with hydrophobic magnesium stearate did not retard the dissolution kinetics of acetaminophen. Future studies are warranted to evaluate tableting behavior of such dry-coated pharmaceutical powders. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  6. Wet storage integrity update

    International Nuclear Information System (INIS)

    Bailey, W.J.; Johnson, A.B. Jr.


    This report includes information from various studies performed under the Wet Storage Task of the Spent Fuel Integrity Project of the Commercial Spent Fuel Management (CSFM) Program at Pacific Northwest Laboratory. An overview of recent developments in the technology of wet storage of spent water reactor fuel is presented. Licensee Event Reports pertaining to spent fuel pools and the associated performance of spent fuel and storage components during wet storage are discussed. The current status of fuel that was examined under the CSFM Program is described. Assessments of the effect of boric acid in spent fuel pool water on the corrosion and stress corrosion cracking of stainless steel and the stress corrosion cracking of stainless steel piping containing stagnant water at spent fuel pools are discussed. A list of pertinent publications is included. 84 references, 21 figures, 11 tables

  7. Leaf wetness distribution within a potato crop (United States)

    Heusinkveld, B. G.


    The Netherlands has a mild maritime climate and therefore the major interest in leaf wetness is associated with foliar plant diseases. During moist micrometeorological conditions (i.e. dew, fog, rain), foliar fungal diseases may develop quickly and thereby destroy a crop quickly. Potato crop monocultures covering several hectares are especially vulnerable to such diseases. Therefore understanding and predicting leaf wetness in potato crops is crucial in crop disease control strategies. A field experiment was carried out in a large homogeneous potato crop in the Netherlands during the growing season of 2008. Two innovative sensor networks were installed as a 3 by 3 grid at 3 heights covering an area of about 2 hectares within two larger potato crops. One crop was located on a sandy soil and one crop on a sandy peat soil. In most cases leaf wetting starts in the top layer and then progresses downward. Leaf drying takes place in the same order after sunrise. A canopy dew simulation model was applied to simulate spatial leaf wetness distribution. The dew model is based on an energy balance model. The model can be run using information on the above-canopy wind speed, air temperature, humidity, net radiation and within canopy air temperature, humidity and soil moisture content and temperature conditions. Rainfall was accounted for by applying an interception model. The results of the dew model agreed well with the leaf wetness sensors if all local conditions were considered. The measurements show that the spatial correlation of leaf wetness decreases downward.

  8. Wetting of real surfaces

    CERN Document Server

    Bormashenko, Edward Yu


    The problem of wetting and drop dynamics on various surfaces is very interesting from both the scientificas well as thepractical viewpoint, and subject of intense research.The results are scattered across papers in journals, sothis workwill meet the need for a unifying, comprehensive work.

  9. WetVegEurope

    NARCIS (Netherlands)

    Landucci, Flavia; Řezníčková, Marcela; Šumberová, Kateřina; Hennekens, S.M.; Schaminée, J.H.J.


    WetVegEurope is a research project ( whose goal is to provide a synthesized formalized classification of the aquatic and marsh vegetation across Europe at the level of phytosociological associations. In order to achieve the project objective, a

  10. Elucidating the mysteries of wetting.

    Energy Technology Data Exchange (ETDEWEB)

    Webb, Edmund Blackburn, III (,; ); Bourdon, Christopher Jay; Grillet, Anne Mary; Sackinger, Philip A.; Grest, Gary Stephen; Emerson, John Allen; Ash, Benjamin Jesse; Heine, David R.; Brooks, Carlton, F.; Gorby, Allen D.


    Nearly every manufacturing and many technologies central to Sandia's business involve physical processes controlled by interfacial wetting. Interfacial forces, e.g. conjoining/disjoining pressure, electrostatics, and capillary condensation, are ubiquitous and can surpass and even dominate bulk inertial or viscous effects on a continuum level. Moreover, the statics and dynamics of three-phase contact lines exhibit a wide range of complex behavior, such as contact angle hysteresis due to surface roughness, surface reaction, or compositional heterogeneities. These thermodynamically and kinetically driven interactions are essential to the development of new materials and processes. A detailed understanding was developed for the factors controlling wettability in multicomponent systems from computational modeling tools, and experimental diagnostics for systems, and processes dominated by interfacial effects. Wettability probed by dynamic advancing and receding contact angle measurements, ellipsometry, and direct determination of the capillary and disjoining forces. Molecular scale experiments determined the relationships between the fundamental interactions between molecular species and with the substrate. Atomistic simulations studied the equilibrium concentration profiles near the solid and vapor interfaces and tested the basic assumptions used in the continuum approaches. These simulations provide guidance in developing constitutive equations, which more accurately take into account the effects of surface induced phase separation and concentration gradients near the three-phase contact line. The development of these accurate models for dynamic multicomponent wetting allows improvement in science based engineering of manufacturing processes previously developed through costly trial and error by varying material formulation and geometry modification.

  11. Wetting of porous solids. (United States)

    Patkar, Saket; Chaudhuri, Parag


    This paper presents a simple, three stage method to simulate the mechanics of wetting of porous solid objects, like sponges and cloth, when they interact with a fluid. In the first stage, we model the absorption of fluid by the object when it comes in contact with the fluid. In the second stage, we model the transport of absorbed fluid inside the object, due to diffusion, as a flow in a deforming, unstructured mesh. The fluid diffuses within the object depending on saturation of its various parts and other body forces. Finally, in the third stage, oversaturated parts of the object shed extra fluid by dripping. The simulation model is motivated by the physics of imbibition of fluids into porous solids in the presence of gravity. It is phenomenologically capable of simulating wicking and imbibition, dripping, surface flows over wet media, material weakening, and volume expansion due to wetting. The model is inherently mass conserving and works for both thin 2D objects like cloth and for 3D volumetric objects like sponges. It is also designed to be computationally efficient and can be easily added to existing cloth, soft body, and fluid simulation pipelines.

  12. Wetting Transition and Line Tension of Oil on Water (United States)

    Matsubara, H.; Aratono, M.

    Wetting has attracted wide attention in the field of applied chemistry because of its crucial importance in industrial operations such as coating, painting, and lubrication. Here, we summarize our fundamental understandings of surfactant-assisted wetting transitions which we have found and studied for the last ten years. The difference between the surfactant-assisted wetting transitions and existing ones is discussed. Moreover, the relation between wetting transitions and the stability of the three-phase contact line is examined in terms of the line tension of oil lenses.

  13. The wetting transition in water (United States)

    Friedman, Serah Ruth

    This work addresses both the design and experimental procedure for finding the wetting transition in water on a variety of solid surfaces. When a liquid drop is placed onto a solid surface it will either completely spread out or form a finite contact angle between 0 and 180 degrees. When a drop spreads, forming a film across the surface, this is called complete wetting. If a drop forms a finite contact angle with the surface, this is called partial wetting. A wetting transition is a surface phase transition from partial to complete wetting. This work is the first to experimentally measure the wetting transition in water on a solid surface. The temperature at which the wetting transition occurs is called the wetting temperature. The wetting temperature for solid-liquid-vapor systems can be theoretically predicted using both molecular dynamics simulations and density functional theory. Density functional theory predicts, with reasonable accuracy, the wetting temperature of "simple" non-polar liquids on a solid surface. The accuracy of density functional theory in predicting wetting temperature has yet to be experimentally tested on more complex polar liquids, and more specifically on water. In this work, we set out to measure the wetting transition in water on a variety of surfaces, namely: Graphite, Sapphire, Quartz, Mica, Gold, Silicon and Hexagonal Boron Nitride.

  14. Molecular Dynamics Simulations for Predicting Surface Wetting

    Directory of Open Access Journals (Sweden)

    Jing Chen


    Full Text Available The investigation of wetting of a solid surface by a liquid provides important insights; the contact angle of a liquid droplet on a surface provides a quantitative measurement of this interaction and the degree of attraction or repulsion of that liquid type by the solid surface. Molecular dynamics (MD simulations are a useful way to examine the behavior of liquids on solid surfaces on a nanometer scale. Thus, we surveyed the state of this field, beginning with the fundamentals of wetting calculations to an examination of the different MD methodologies used. We highlighted some of the advantages and disadvantages of the simulations, and look to the future of computer modeling to understand wetting and other liquid-solid interaction phenomena.

  15. Wet-dog shake (United States)

    Dickerson, Andrew; Mills, Zack; Hu, David


    The drying of wet fur is a critical to mammalian heat regulation. We investigate experimentally the ability of hirsute animals to rapidly oscillate their bodies to shed water droplets, nature's analogy to the spin cycle of a washing machine. High-speed videography and fur-particle tracking is employed to determine the angular position of the animal's shoulder skin as a function of time. We determine conditions for drop ejection by considering the balance of surface tension and centripetal forces on drops adhering to the animal. Particular attention is paid to rationalizing the relationship between animal size and oscillation frequency required to self-dry.

  16. Optical wet steam monitor (United States)

    Maxey, L.C.; Simpson, M.L.


    A wet steam monitor determines steam particle size by using laser doppler velocimeter (LDV) device to produce backscatter light. The backscatter light signal is processed with a spectrum analyzer to produce a visibility waveform in the frequency domain. The visibility waveform includes a primary peak and a plurality of sidebands. The bandwidth of at least the primary frequency peak is correlated to particle size by either visually comparing the bandwidth to those of known particle sizes, or by digitizing the waveform and comparing the waveforms electronically. 4 figures.

  17. Wet steam wetness measurement in a 10 MW steam turbine

    Directory of Open Access Journals (Sweden)

    Kolovratník Michal


    Full Text Available The aim of this paper is to introduce a new design of the extinction probes developed for wet steam wetness measurement in steam turbines. This new generation of small sized extinction probes was developed at CTU in Prague. A data processing technique is presented together with yielded examples of the wetness distribution along the last blade of a 10MW steam turbine. The experimental measurement was done in cooperation with Doosan Škoda Power s.r.o.

  18. Wetting front instability in an initially wet unsaturated fracture

    International Nuclear Information System (INIS)

    Nicholl, M.J.; Glass, R.J.; Nguyen, H.A.


    Experimental results exploring gravity-driven wetting from instability in a pre-wetted, rough-walled analog fractures such as those at Yucca Mountain are presented. Initial conditions considered include a uniform moisture field wetted to field capacity of the analog fracture and the structured moisture field created by unstable infiltration into an initially dry fracture. As in previous studies performed under dry initial conditions, instability was found to result both at the cessation of stable infiltration and at flux lower than the fracture capacity under gravitational driving force. Individual fingers were faster, narrower, longer, and more numerous than observed under dry initial conditions. Wetting fronts were found to follow existing wetted structure, providing a mechanism for rapid recharge and transport

  19. Wetting Hierarchy in Oleophobic 3D Electrospun Nanofiber Networks. (United States)

    Stachewicz, Urszula; Bailey, Russell J; Zhang, Hao; Stone, Corinne A; Willis, Colin R; Barber, Asa H


    Wetting behavior between electrospun nanofibrous networks and liquids is of critical importance in many applications including filtration and liquid-repellent textiles. The relationship between intrinsic nanofiber properties, including surface characteristics, and extrinsic nanofibrous network organization on resultant wetting characteristics of the nanofiber network is shown in this work. Novel 3D imaging exploiting focused ion beam (FIB) microscopy and cryo-scanning electron microscopy (cryo-SEM) highlights a wetting hierarchy that defines liquid interactions with the network. Specifically, small length scale partial wetting between individual electrospun nanofibers and low surface tension liquids, measured both using direct SEM visualization and a nano Wilhelmy balance approach, provides oleophobic surfaces due to the high porosity of electrospun nanofiber networks. These observations conform to a metastable Cassie-Baxter regime and are important in defining general rules for understanding the wetting behavior between fibrous solids and low surface tension liquids for omniphobic functionality.

  20. Detection of component segregation in granules manufactured by high shear granulation with over-granulation conditions using near-infrared chemical imaging. (United States)

    Koide, Tatsuo; Nagato, Takuya; Kanou, Yoshiyuki; Matsui, Kou; Natsuyama, Susumu; Kawanishi, Toru; Hiyama, Yukio


    The objective of this study was to evaluate the high shear granulation process using near-infrared (NIR) chemical imaging technique and to make the findings available for pharmaceutical development. We prepared granules and tablets made under appropriate- and over-granulation conditions with high shear granulation and observed these granules and tablets using NIR chemical imaging system. We found an interesting phenomenon: lactose agglomeration and segregation of ingredients occurred in experimental tablets when over-granulation conditions, including greater impeller rotation speeds and longer granulation times, were employed. Granules prepared using over-granulation conditions were larger and had progressed to the consolidation stage; segregation between ethenzamide and lactose occurred within larger granules. The segregation observed here is not detectable using conventional analytical technologies such as high pressure liquid chromatography (HPLC) because the content of the granules remained uniform despite the segregation. Therefore, granule visualization using NIR chemical imaging is an effective method for investigating and evaluating the granulation process. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Statistical analysis and comparison of a continuous high shear granulator with a twin screw granulator: Effect of process parameters on critical granule attributes and granulation mechanisms. (United States)

    Meng, Wei; Kotamarthy, Lalith; Panikar, Savitha; Sen, Maitraye; Pradhan, Shankali; Marc, Michaelis; Litster, James D; Muzzio, Fernando J; Ramachandran, Rohit


    This study is concerned with identifying the design space of two different continuous granulators and their respective granulation mechanisms. Performance of a continuous high shear granulator and a twin screw granulator with paracetamol formulations were examined by face-centered cubic design, which focused on investigating key performance metrics, namely, granule size, porosity, flowability and particle morphology of granules as a function of essential input process parameters (liquid content, throughput and rotation speed). Liquid and residence time distribution tests were also performed to gain insights into the liquid-powder mixing and flow behavior. The results indicated that continuous high shear granulation was more sensitive to process variation and produced spherical granules with monomodal size distribution and distinct internal structure and strength variation. Twin screw granulation with such a particular screw configuration showed narrower design space and granules were featured with multimodal size distribution, irregular shape, less detectible porosity difference and tighter range of strength. Granulation mechanisms explored on the basis of nucleation and growth regime maps revealed that for most cases liquid binder was uniformly distributed with fast droplet penetration into the powder bed and that granule consolidation and coalescence mainly took place in the nucleation, steady growth and rapid growth regimes. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Wet Deposition Flux of Reactive Organic Carbon (United States)

    Safieddine, S.; Heald, C. L.


    Reactive organic carbon (ROC) is the sum of non-methane volatile organic compounds (NMVOCs) and primary and secondary organic aerosols (OA). ROC plays a key role in driving the chemistry of the atmosphere, affecting the hydroxyl radical concentrations, methane lifetime, ozone formation, heterogeneous chemical reactions, and cloud formation, thereby impacting human health and climate. Uncertainties on the lifecycle of ROC in the atmosphere remain large. In part this can be attributed to the large uncertainties associated with the wet deposition fluxes. Little is known about the global magnitude of wet deposition as a sink of both gas and particle phase organic carbon, making this an important area for research and sensitivity testing in order to better understand the global ROC budget. In this study, we simulate the wet deposition fluxes of the reactive organic carbon of the troposphere using a global chemistry transport model, GEOS-Chem. We start by showing the current modeled global distribution of ROC wet deposition fluxes and investigate the sensitivity of these fluxes to variability in Henry's law solubility constants and spatial resolution. The average carbon oxidation state (OSc) is a useful metric that depicts the degree of oxidation of atmospheric reactive carbon. Here, we present for the first time the simulated gas and particle phase OSc of the global troposphere. We compare the OSc in the wet deposited reactive carbon flux and the dry deposited reactive carbon flux to the OSc of atmospheric ROC to gain insight into the degree of oxidation in deposited material and, more generally, the aging of organic material in the troposphere.

  3. Nuclear turbine efficiency improvement by wet steam study

    International Nuclear Information System (INIS)

    Nishikawa, Tsuyoshi; Morson, A.; Markytan, R.


    Most of the turbine used at the nuclear power plant are operated at environment of wet steam, which composes of a big factor of its inner loss in comparison with those of the thermal power plant. If an analytical method predictable on behavior of the wet steam is established, it could be upgraded efficiency of the turbine and also reliability against corrosion formed by moisture. This study, therefore, aims at understanding of physical property of the wet steam flow scarcely known at present, development of an optimum turbine cascade design tool reflected by the property, development of a turbine cascade design reducible of steam loss due to wet steam by using the tool, and development on a method of removing moisture in the turbine to its outer portion. For the tool, a new three dimensional flow numerical analysis is necessary to be developed, to aim at accurately and numerically understanding of the behavior of wet steam. As this study is in advancing now, by using a turbine cascade optimized on the wet steam flow and a developed moisture removing apparatus, about 0.6 % of upgrading in turbine efficiency can be predicted in comparison with that of the advanced aero-cascade of the GE Corporation. (G.K.)

  4. Wetting of Water on Graphene

    KAUST Repository

    Bera, Bijoyendra


    The wetting properties of graphene have proven controversial and difficult to assess. The presence of a graphene layer on top of a substrate does not significantly change the wetting properties of the solid substrate, suggesting that a single graphene layer does not affect the adhesion between the wetting phase and the substrate. However, wetting experiments of water on graphene show contact angles that imply a large amount of adhesion. Here, we investigate the wetting of graphene by measuring the mass of water vapor adsorbing to graphene flakes of different thickness at different relative humidities. Our experiments unambiguously show that the thinnest of graphene flakes do not adsorb water, from which it follows that the contact angle of water on these flakes is ~180o. Thicker flakes of graphene nanopowder, on the other hand, do adsorb water. A calculation of the van der Waals (vdW) interactions that dominate the adsorption in this system confirms that the adhesive interactions between a single atomic layer of graphene and water are so weak that graphene is superhydrophobic. The observations are confirmed in an independent experiment on graphene-coated water droplets that shows that it is impossible to make liquid \\'marbles\\' with molecularly thin graphene.

  5. Does Surface Roughness Amplify Wetting?

    Czech Academy of Sciences Publication Activity Database

    Malijevský, Alexandr


    Roč. 141, č. 18 (2014), s. 184703 ISSN 0021-9606 R&D Projects: GA ČR GA13-09914S Institutional support: RVO:67985858 Keywords : density functional theory * wetting * roughness Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.952, year: 2014

  6. Influence of High Shear Dispersion on the Production of Cellulose Nanofibers by Ultrasound-Assisted TEMPO-Oxidation of Kraft Pulp. (United States)

    Loranger, Eric; Piché, André-Olivier; Daneault, Claude


    Cellulose nanofibers can be produced using a combination of TEMPO, sodium bromide (NaBr) and sodium hypochlorite, and mechanical dispersion. Recently, this process has been the subject of intensive investigation. However, studies on the aspects of mechanical treatment of this process remain marginal. The main objective of this study is to evaluate the high shear dispersion parameters (e.g., consistency, stator-rotor gap, recirculation rate and pH) and determine their influences on nanocellulose production using ultrasound-assisted TEMPO-oxidation of Kraft pulp. All nanofiber gels produced in this study exhibited rheological behaviors known as shear thinning. From all the dispersion parameters, the following conditions were identified as optimal: 0.042 mm stator-rotor gap, 200 mL/min recycle rate, dispersion pH of 7 and a feed consistency of 2%. High quality cellulose gel could be produced under these conditions. This finding is surely of great interest for the pulp and paper industry.

  7. Influence of High Shear Dispersion on the Production of Cellulose Nanofibers by Ultrasound-Assisted TEMPO-Oxidation of Kraft Pulp

    Directory of Open Access Journals (Sweden)

    Claude Daneault


    Full Text Available Cellulose nanofibers can be produced using a combination of TEMPO, sodium bromide (NaBr and sodium hypochlorite, and mechanical dispersion. Recently, this process has been the subject of intensive investigation. However, studies on the aspects of mechanical treatment of this process remain marginal. The main objective of this study is to evaluate the high shear dispersion parameters (e.g., consistency, stator-rotor gap, recirculation rate and pH and determine their influences on nanocellulose production using ultrasound-assisted TEMPO-oxidation of Kraft pulp. All nanofiber gels produced in this study exhibited rheological behaviors known as shear thinning. From all the dispersion parameters, the following conditions were identified as optimal: 0.042 mm stator-rotor gap, 200 mL/min recycle rate, dispersion pH of 7 and a feed consistency of 2%. High quality cellulose gel could be produced under these conditions. This finding is surely of great interest for the pulp and paper industry.

  8. Physical chemistry of wet chemical anisotropic etching of silicon

    NARCIS (Netherlands)

    Elwenspoek, Michael Curt


    In this paper we explain a view to understand the anisotropy of the etching of silicon in certain wet chemical agents (such as KOH). The starting point is the assumption that the [Left angle bracket]111[Right Angle Bracket] face of silicon is a flat face, the etch rate of which is then governed by a

  9. Educators' understanding of workplace bullying | de Wet | South ...

    African Journals Online (AJOL)

    South African Journal of Education. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 34, No 1 (2014) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected ...

  10. Kinetic effects in dynamic wetting (United States)

    Sprittles, James


    The maximum speed at which a liquid can wet a solid is limited by the need to displace gas lubrication films in front of the moving contact line. The characteristic height of these films is often comparable to the mean free path in the gas so that hydrodynamic models do not adequately describe the flow physics. In this talk, I will develop a model which incorporates kinetic effects in the gas, via the Boltzmann equation, and can predict experimentally-observed increases in the maximum speed of wetting when (a) the liquid's viscosity is varied, (b) the ambient gas pressure is reduced or (c) the meniscus is confined. This work was supported by the Leverhulme Trust (Research Project Grant) and the Engineering & Physical Sciences Research Council (Grant EP/N016602/1).

  11. Formative Assessment Probes: Wet Jeans (United States)

    Keeley, Page


    Picture a wet towel or a puddle of water on a hot, sunny day. An hour later, the towel is dry and the puddle no longer exists. What happened to the water? Where did it go? These are questions that reveal myriad interesting student ideas about evaporation and the water cycle--ideas that provide teachers with a treasure trove of data they can use to…

  12. Wet water glass production plant

    Directory of Open Access Journals (Sweden)

    Stanković Mirjana S.


    Full Text Available The IGPC Engineering Department designed basic projects for a wet hydrate dissolution plant, using technology developed in the IGPC laboratories. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, a production plant of a capacity of 75,000 t/y was manufactured, at "Zeolite Mira", Mira (VE, Italy, in 1997. and 1998, increasing detergent zeolite production, from 50,000 to 100,000 t/y. Several goals were realized by designing a wet hydrate dissolution plant. The main goal was increasing the detergent zeolite production. The technological cycle of NaOH was closed, and no effluents emitted, and there is no pollution (except for the filter cake. The wet water glass production process is fully automatized, and the product has uniform quality. The production process can be controlled manually, which is necessary during start - up, and repairs. By installing additional process equipment (centrifugal pumps and heat exchangers technological bottlenecks were overcome, and by adjusting the operation of autoclaves, and water glass filters and also by optimizing the capacities of process equipment.

  13. European wet deposition maps based on measurements

    NARCIS (Netherlands)

    Leeuwen EP van; Erisman JW; Draaijers GPJ; Potma CJM; Pul WAJ van; LLO


    To date, wet deposition maps on a European scale have been based on long-range transport model results. For most components wet deposition maps based on measurements are only available on national scales. Wet deposition maps of acidifying components and base cations based on measurements are needed

  14. Wetting behavior of flax fibers as reinforcement for polypropylene. (United States)

    Aranberri-Askargorta, Ibon; Lampke, Thomas; Bismarck, Alexander


    The wetting behavior of several flax (cellulose as reference) and polypropylene fibers is characterized by measuring the wetting rates (penetration velocities) of a series of liquids using the capillary rise technique. This present paper aims to provide a deeper understanding of the complex nature of natural fibers and their surface properties. The fiber surface tensions are estimated from plots of the normalized wetting rate as a function of the surface tension of the liquids assuming, in analogy to Zisman's method, that the maximum of the normalized wetting rate corresponds to the solid surface tension. The estimated surface tensions of the investigated flax fibers indicate that all the fibers are quite "hydrophobic." The method used to separate the fibers from the rest of the plants has a large influence on the estimated fiber surface tensions. In the case of polypropylene (PP) fibers, the estimated surface tension corresponds well with literature data. Grafting small amounts of maleic acid anhydrite (MAH) onto the PP surfaces will not affect the wetting behavior and, therefore, the surface tension, whereas grafting larger amounts (10 wt%) of MAH causes the polymer surface tension to increase significantly. Additional pH-dependent zeta-potential measurements show that even the "pure" PP-fibers contain acidic surface functions, possibly due to further processing at elevated temperatures (thermal degradation or other aging processes).

  15. An analysis of Simpson's notebook data on the wet nurse. (United States)

    Mander, Rosemary


    to understand the meaning of the qualitative data included in the Notebook of wet nurses kept by James Young Simpson. quantitative and qualitative analysis of data in an historical document. a list of wet nurses kept by a 'Professor of Midwifery' in mid-19th century Edinburgh. the Notebook lists the names and other details of 749 women. the Notebook indicates how the wet nurse was recruited, the implications for her baby, how she negotiated her role and the decision-making around her recruitment. the ambiguity of this medical pioneer's decision-making is demonstrated. Simpson's scientific credentials may have featured much rhetoric. While in the forefront of many obstetric and medical developments, Simpson was regressive in his support for wet nursing. The social input into the selection of the wet nurse has not been identified previously. the woman's ability to negotiate her terms of employment emerges. The social determinants of baby feeding decisions, identified in this document, have assumed greater significance since the time that this Notebook was written.

  16. Analysis of wet granulation process with Plackett-Burman design--case study. (United States)

    Woyna-Orlewicz, Krzysztof; Jachowicz, Renata


    According to Process Analytical Technology perspective, drug product quality should be ensured by manufacturing process design. Initial step of the process analysis is investigation of critical process parameters (CPPs). It is generally accepted to type the CPPs based on project team knowledge and experience [5]. This paper describes the use of Design of Experiments tool for selection of the CPPs. Seven factors of wet granulation process were investigated for criticality. Low and high levels of each factor represented maximal and minimal settings of wide operational ranges. Granulates were produced in line with Plackett-Burman experimental matrix, blended with extra-granular excipients and compressed into tablets. Semi-products and final products were tested. Out of specification result of any critical quality attribute was treated as critical failure. The high-shear granulation factors, i.e. quantity of binding solution, rotational speed of impeller and wet massing time were considered of critical importance. Operational ranges of the parameters were optimized. The process performance was confirmed in qualification trials.


    International Nuclear Information System (INIS)

    Hugo S. Caram; Natalie Foster


    The objective was to visualize the flow of granular materials in flat bottomed silo. This was done by for dry materials introducing mustard seeds and poppy seeds as tracer particles and imaging them using Nuclear Magnetic Resonance. The region sampled was a cylinder 25 mm in diameter and 40 mm in length. Eight slices containing 128*128 to 256*256 pixels were generated for each image. The size of the silo was limited by the size of the high resolution NMR imager available. Cross-sections of 150mm flat bottomed silos, with the tracer layers immobilized by a gel, showed similar qualitative patterns for both dry and wet granular solids

  18. Wet season range fidelity in a tropical migratory ungulate. (United States)

    Morrison, Thomas A; Bolger, Douglas T


    1. In migratory populations, the degree of fidelity and dispersal among seasonal ranges is an important population process with consequences for demography, management, sensitivity to habitat change and adaptation to local environmental conditions. 2. Characterizing patterns of range fidelity in ungulates, however, has remained challenging because of the difficulties of following large numbers of marked individuals across multiple migratory cycles and of identifying the appropriate scale of analysis. 3. We examined fidelity to wet season (i.e. breeding) ranges in a recently declining population of wildebeest Connochaetes taurinus Burchell in northern Tanzania across 3 years. We used computer-assisted photographic identification and capture-recapture to characterize return patterns to three wet season ranges that were ecologically discrete and topographically isolated from one another. 4. Among 2557 uniquely identified adult wildebeest, we observed 150 recaptures across consecutive wet seasons. Between the two migratory subpopulations, the probability of remaining faithful to wet season areas ranged between 0·82 and 1·00. Animals from a non-migratory segment of the population (near Lake Manyara National Park) were rarely observed in other wet season ranges, despite proximity to one of the migratory pathways. 5. We found no effect of sex on an individuals' probability of switching wet season ranges. However, the breeding status of females in year i had a strong influence on patterns of range selection in year i + 1, with surviving breeders over three times as likely to switch ranges as non-breeders. 6. Social-group associations between pairs of recaptured animals were random with respect to an individual's wet season range during the previous or forthcoming wet seasons, suggesting that an individual's herd identity during the dry season does not predict wet season range selection. 7. Examining fidelity and dispersal in terrestrial migrations improves

  19. Effect of wetting-drying cycles on soil desiccation cracking behaviour

    Directory of Open Access Journals (Sweden)

    Tang Chao-Sheng


    Full Text Available Better understanding the desiccation cracking process is essential in analysing drought effects on soil hydraulic and mechanical properties through consideration of the atmosphere-ground interaction. Laboratory tests were conducted to investigate the consequence of wetting-drying cycles on the initiation and propagation characteristics of desiccation cracks on soil surface. Initially saturated slurry specimens were prepared and subjected to five subsequent wetting-drying cycles. Image processing technique was employed to quantitatively analyze the morphology characteristics of crack patterns formed during each drying path. The results show that the desiccation cracking behaviour of soil is significantly affected by the wetting-drying cycles. Before the third wetting-drying cycle is reached, the surface crack ratio and the average crack width increases while the average clod area decreases with increasing the number of wetting-drying cycles. The number of intersections and crack segments per unit area reaches the peak values after the second wetting-drying cycle. After the third wetting-drying cycle is reached, the effect of increasing wetting-drying cycles on crack patterns is insignificant. Moreover, it is observed that the applied wetting-drying cycles are accompanied by a continual reconstruction of soil structure. The initial homogenous slurry structure is completely replaced with aggregated structure after the third cycles, and a significant increase in the inter-aggregate porosity can be observed.

  20. Drop splashing is independent of substrate wetting (United States)

    Latka, Andrzej; Boelens, Arnout M. P.; Nagel, Sidney R.; de Pablo, Juan J.


    A liquid drop impacting a dry solid surface with sufficient kinetic energy will splash, breaking apart into numerous secondary droplets. This phenomenon shows many similarities to forced wetting, including the entrainment of air at the contact line. Because of these similarities and the fact that forced wetting has been shown to depend on the wetting properties of the surface, existing theories predict splashing to depend on wetting properties as well. However, using high-speed interference imaging, we observe that at high capillary numbers wetting properties have no effect on splashing for various liquid-surface combinations. Additionally, by fully resolving the Navier-Stokes equations at length and time scales inaccessible to experiments, we find that the shape and motion of the air-liquid interface at the contact line/edge of the droplet are independent of wettability. We use these findings to evaluate existing theories and to compare splashing with forced wetting.

  1. Wetting and evaporation of binary mixture drops. (United States)

    Sefiane, Khellil; David, Samuel; Shanahan, Martin E R


    Experimental results on the wetting behavior of water, methanol, and binary mixture sessile drops on a smooth, polymer-coated substrate are reported. The wetting behavior of evaporating water/methanol drops was also studied in a water-saturated environment. Drop parameters (contact angle, shape, and volume) were monitored in time. The effects of the initial relative concentrations on subsequent evaporation and wetting dynamics were investigated. Physical mechanisms responsible for the various types of wetting behavior during different stages are proposed and discussed. Competition between evaporation and hydrodynamic flow are evoked. Using an environment saturated with water vapor allowed further exploration of the controlling mechanisms and underlying processes. Wetting stages attributed to differential evaporation of methanol were identified. Methanol, the more volatile component, evaporates predominantly in the initial stage. The data, however, suggest that a small proportion of methanol remained in the drop after the first stage of evaporation. This residual methanol within the drop seems to influence subsequent wetting behavior strongly.

  2. Wet motor geroter fuel pump

    Energy Technology Data Exchange (ETDEWEB)

    Wiernicki, M.V.


    This patent describes a wet motor gerotor fuel pump for pumping fuel from a fuel source to an internal combustion which consists of: gerotor pump means comprising an inner pump gear, an outer pump gear, and second tang means located on one of the inner and outer pump gears. The second tang means further extends in a second radial direction radially offset from the first radial direction and forms a driving connection with the first tang means such that the fuel pump pumps fuel from the fuel source into the narrow conduit inlet chamber, through the gerotor pump means past the electric motor means into the outlet housing means substantially along the flow axis to the internal combustion engine.

  3. Carbon nanotube fiber spun from wetted ribbon (United States)

    Zhu, Yuntian T; Arendt, Paul; Zhang, Xiefei; Li, Qingwen; Fu, Lei; Zheng, Lianxi


    A fiber of carbon nanotubes was prepared by a wet-spinning method involving drawing carbon nanotubes away from a substantially aligned, supported array of carbon nanotubes to form a ribbon, wetting the ribbon with a liquid, and spinning a fiber from the wetted ribbon. The liquid can be a polymer solution and after forming the fiber, the polymer can be cured. The resulting fiber has a higher tensile strength and higher conductivity compared to dry-spun fibers and to wet-spun fibers prepared by other methods.

  4. Tropopause Pressure May Explain California Droughts and Wet Period (United States)

    Mazdiyasni, O.; AghaKouchak, A.


    Sea surface temperatures and teleconnection patterns such as El Nino/La Nina are considered the main culprits behind major California droughts. However, the underlying relationship between sea surface temperatures (SSTs) and precipitation anomalies is relatively weak. In 2015-2016 the most extreme El Nino did not lead to a wet season as expected, which triggered a series of studies on this topic. Here we show that tropopause level pressure in a region in the northeastern Pacific Ocean (dubbed the PARS-NEP region) plays a major role in whether California will experience a wet or dry year and often dominates the role of SST-based teleconnections. Our results indicate that pressure in the PARS-NEP region Granger-Causes precipitation in California during the wet season. We show that when pressure in the PARS-NEP region is in the lower (upper) tertile, 85% of wet seasons across California have a positive (negative) precipitation anomaly. The observed relationship between PARS-NEP and California precipitation is stronger than all the commonly used SST-based climatic indictors frequently used for understanding causes of droughts.

  5. Electrostatic cloaking of surface structure for dynamic wetting (United States)

    Shiomi, Junichiro; Nita, Satoshi; Do-Quang, Minh; Wang, Jiayu; Chen, Yu-Chung; Suzuki, Yuji; Amberg, Gustav


    Dynamic wetting problems are fundamental to the understanding of the interaction between liquids and solids. Even in a superficially simple experimental situation, such as a droplet spreading over a dry surface, the result may depend not only on the liquid properties but also strongly on the substrate-surface properties; even for macroscopically smooth surfaces, the microscopic geometrical roughness can be important. In addition, as surfaces may often be naturally charged, or electric fields are used to manipulate fluids, electric effects are crucial components that influence wetting phenomena. Here we investigate the interplay between electric forces and surface structures in dynamic wetting. While surface microstructures can significantly hinder the spreading, we find that the electrostatics can ``cloak'' the microstructures, i.e. deactivate the hindering. We identify the physics in terms of reduction in contact-line friction, which makes the dynamic wetting inertial force dominant and insensitive to the substrate properties. This work was financially supported in part by, the Japan Society for the Promotion of Science, Swedish Governmental Agency for Innovation Systems, and the Japan Science and Technology Agency.

  6. Characteristics of wet work in nurses

    NARCIS (Netherlands)

    Jungbauer, FHW; Steenstra, FB; Groothoff, JW; Coenraads, PJ

    Background objectives: Nursing is known for its high prevalence of hand dermatitis, mainly caused by the intense exposure to wet work in nursing activities. We aimed to study the characteristics of wet work exposure in nursing. Method: Trained observers monitored the duration and frequency of

  7. Leaf Wetness within a Lily Canopy

    NARCIS (Netherlands)

    Jacobs, A.F.G.; Heusinkveld, B.G.; Klok, E.J.


    A wetness duration experiment was carried out within a lily field situated adjacent to coastal dunes in the Netherlands. A within-canopy model was applied to simulate leaf wetness in three layers, with equal leaf area indices, within the canopy. This simulation model is an extension of an existing

  8. Ovine wet carcass syndrome of unknown aetiology

    African Journals Online (AJOL)

    A condition of unknown aetiology, known as 'the wet sheep carcass syndrome' has led to the loss of about ... aetiology. Introduction. Wet sheep carcasses were seen with increasing frequency at abattoirs from January 1981. ... the holding pens, and transport stress. In the high incidence area (see Figure 1), feeding systems.

  9. Curvature controlled wetting in two dimensions

    DEFF Research Database (Denmark)

    Gil, Tamir; Mikheev, Lev V.


    . As the radius of the substrate r0→∞, the leading effect of the curvature is adding the Laplace pressure ΠL∝r0-1 to the pressure balance in the film. At temperatures and pressures under which the wetting is complete in planar geometry, Laplace pressure suppresses divergence of the mean thickness of the wetting...

  10. Long term wet spent nuclear fuel storage

    International Nuclear Information System (INIS)


    The meeting showed that there is continuing confidence in the use of wet storage for spent nuclear fuel and that long-term wet storage of fuel clad in zirconium alloys can be readily achieved. The importance of maintaining good water chemistry has been identified. The long-term wet storage behaviour of sensitized stainless steel clad fuel involves, as yet, some uncertainties. However, great reliance will be placed on long-term wet storage of spent fuel into the future. The following topics were treated to some extent: Oxidation of the external surface of fuel clad, rod consolidation, radiation protection, optimum methods of treating spent fuel storage water, physical radiation effects, and the behaviour of spent fuel assemblies of long-term wet storage conditions. A number of papers on national experience are included

  11. Teaching Teaching & Understanding Understanding

    DEFF Research Database (Denmark)


    "Teaching Teaching & Understanding Understanding" is a 19-minute award-winning short-film about teaching at university and higher-level educational institutions. It is based on the "Constructive Alignment" theory developed by Prof. John Biggs. The film delivers a foundation for understanding what...

  12. Catechol-Cation Synergy in Wet Adhesive Materials (United States)

    Maier, Gregory Peter

    In physiological fluids and seawater, adhesion of synthetic polymers to solid surfaces is impaired by high salt, pH, and hydration. However, mussels have evolved effective strategies for wet adhesion despite these impediments. Inspection of mussel foot proteins (Mfps) provides insights into adhesive adaptations. Catecholic Dopa (3,4-dihydroxyphenylalanine) and lysine residues are present in high mole percent in the interfacial Mfps. The siderophore cyclic trichrysobactin also contains high mole percent of catechol and lysine and serves as a simplified mimic of Mfps. This work is focused on use of Mfp-mimetic siderophores and synthetic siderophore analogs as model systems for dissecting the chemical and physical interactions that enable wet adhesion. Variation in number and identity of functional groups appended to the synthetic siderophore analogs allows identification of the specific contributions of those functional groups to wet adhesion. Both catechol and amine functional groups are critical to strong wet adhesion. The primary amine of lysine and catechol cooperatively displace interfacial hydration and bind to the underlying substrate. Variation in the amine identity as well as the amine to catechol ratio within siderophore analogs also has a significant impact on wet adhesive performance. Catechol undergoes a pH-dependent autoxidation in which higher pH leads to faster oxidation by dioxygen. This oxidation abolishes all adhesion of Mfps to mica by pH 7.5, yet many applications of synthetic wet adhesives require adhesion at physiological or oceanic pH. A better understanding of catechol redox chemistry is critical to the design of wet adhesives. To this end, the pH-dependent autoxidation of catechol and substituted catechols was investigated and results are consistent with a mechanism in which O2 oxidizes both the mono-deprotonated and di-deprotonated catechol. A linear Hammett correlation for the pH-independent second order rate constants for catechol

  13. Technical Efficiency of Wet Season Melon Farming

    Directory of Open Access Journals (Sweden)

    Ananti Yekti


    Full Text Available Melon is one of high-value horticulture commodity which is cultivated widely in Kulon Progo regency. The nature of agricultural products is heavily dependent on the season, so it causes the prices of agricultural products always fluctuated every time. In wet season the price of agricultural products tends to be more expensive. Melon cultivation in wet season provide an opportunity to earn higher profits than in the dry season. The price of agricultural products tends to be more expensive in wet season, thus melon cultivation in wet season prospectively generate high profits. In order to achieve high profitability, melon farming has to be done efficiently. Objective of this study was to 1 determined the factors that influence melon production in wet season 2 measured technical efficiency of melon farming and 3 identified the factors that influanced technical efficiency. Data collected during April – June 2014. Location determined by multistage cluster sampling. 45 samples of farmers who cultivated melon during wet season obtained based on quota sampling technique. Technical efficiency was measured using Cobb-Douglas Stochastic Frontier. The result reveals that 1 land use, quantity of seed, K fertilizer contributed significantly increasing melon production, while N fertilizer decreased melon production significantly 2 technical efficiency indeces ranged from 0.40 to 0.99, with a mean of  0.77; 3 farmer’s experience gave significant influence to technical efficiency of melon farming in wet season.

  14. Observation of nonlinear sloshing induced by wetting dynamics (United States)

    Michel, Guillaume; Pétrélis, François; Fauve, Stéphan


    Back-and-forth oscillations of a container filled with fluid often result in spilling as the gravest mode gets excited, a well-known phenomenon experienced in everyday life and of particular importance in industry. Our understanding of sloshing is largely restricted to linear response, and existing extensions mostly focus on nonlinear coupling between modes. Linear theory is expected to correctly model the dynamics of the system as long as the amplitude of the mode remains small compared to another length scale, so far unknown. Using a fluid in the vicinity of its critical point, we demonstrate that in perfect wetting this length scale is neither the wavelength nor the capillary length but a much shorter one, the thickness of the boundary layer. Above this crossover length scale, the resonance frequency remains roughly constant while dissipation significantly increases. We also show that dynamical wetting is involved in both linear and nonlinear dissipative processes.

  15. Characteristics of wet work in nurses. (United States)

    Jungbauer, F H W; Steenstra, F B; Groothoff, J W; Coenraads, P J


    Nursing is known for its high prevalence of hand dermatitis, mainly caused by the intense exposure to wet work in nursing activities. We aimed to study the characteristics of wet work exposure in nursing. Trained observers monitored the duration and frequency of different wet work activities in 45 randomly chosen nurses from different wards during a morning shift, using a method of continuous observation based on labour-observation techniques. Wet work in intensive care units accounted for 24% of the overall morning shift duration, with a frequency of 49 incidents. This was 16% in dialysis wards, with a frequency of 30 incidents, and 9% on regular wards, with a frequency of 39 incidents. The wet work activities had short mean duration cycles. The mean duration of occlusion by gloves was 3.1 min on regular wards and 6.7 min in intensive care units. The characteristics of wet work in nurses differed substantially, depending on the ward. According to the German regulation TRGS 531, our observations classify nursing as a wet work occupation, due to the frequency of wet work rather than its duration. The mean duration of occlusion in our observations was short, which makes an occlusion-induced irritating effect doubtful. Reduction in wet work exposure in nursing on regular wards could focus on the reduction of the frequency of hand-washing and patient-washing. We suggest increasing the use of gloves for patient washing. Although this will increase exposure to occlusion from gloves, it may reduce the frequency of exposure to water and soap by about a quarter.

  16. How to determine wet-snow instability (United States)

    Reiweger, Ingrid; Mitterer, Christoph


    Processes leading to wet-snow instability are very complex and highly non-linear in time and space. Infiltrating water changes wet-snow strength and other mechanical properties. A high liquid water content presumably favors fracture propagation, which consequently has an influence on the formation of wet slab avalanches. The weakening of snow due to liquid water within the snowpack might be gradual (melt event) or sudden (rain-on-snow event). There are several feedback mechanisms between liquid water and snow stratigraphy, making the weakening process complex. We used modelled stability indices to determine periods with high wet-snow instability. These indices were either based on energy and mass balances indicating critical amounts of water within the snowpack or on simple hydro-mechanical relationships. In addition to the modelled indices, preliminary field studies investigated the fracture initiation and fracture propagation propensity within wet snowpacks. We therefore performed Rutschblock and propagation saw tests in faceted weak layers with different volumetric liquid water contents. Results of simulations and field experiments showed that a critical amount of liquid water combined with a pre-critical snow stratigraphy were relevant for wet-snow instability. The critical amount of water was assumed to drive both failure initiation and fracture propagation. The simulated indices and observed stability tests indicated a high wet-snow instability when the volumetric liquid water content within faceted weak layers exceeded 3. Within our propagation saw test measurements crack propagation propensity even slightly decreased at very low liquid water contents compared to completely dry conditions, presumably due to capillary forces. For liquid water contents higher than 3-4%, however, crack propagation propensity strongly increased, which we assume was due to the weakening of bonds between grains within the increasingly wet weak snow layer. Our results could be used

  17. Catalytic wet oxidation of black liquor


    Viader Riera, Gerard


    The major aspects of wet air oxidation and catalytic wet air oxidation have been reviewed in this work paying special attention to the reaction mechanisms, kinetics and the industrial process. In the experimental section a set of heterogeneous catalysts have been tested in the wet oxidation of non-wood black liquor. The oxidation runs were performed batchwise in a laboratory-scale mechanically stirred slurry reactor for 1 h at a temperature of 170°C and total pressure of 12 bar. Pure oxygen w...

  18. Designer-Wet Micromodels for Studying Potential Changes in Wettability during Microbial Enhanced Oil Recovery (United States)

    Armstrong, R. T.; Wildenschild, D.


    Microbial Enhanced Oil Recovery (MEOR) is a process where microorganisms are used for tertiary recovery of oil. Some bacteria can facilitate the mobilization of oil through the production of amphiphilic compounds called biosurfactants that reduce the interfacial tension (IFT) between immiscible phases. Additionally, most bacteria have an inclination to colonize surfaces and form biofilm, which can change a reservoir's wetting properties or clog preferential flow paths. Herein, we aim to understand changes in wettability during MEOR under mixed wettability conditions within silicon etched micromodels and to identify the type of oil field (i.e. based on wettability) in which MEOR is likely to be most profitable. To quantify porous media wettability, macro-scale indexes (obtained with techniques such as the Carter or Amott methods) are used regularly. However, these measurements lack the capability for characterization of changes in wettability during MEOR treatment, and only provide macro-scale information. In an effort to understand micro-scale temporal and spatial changes in wettability we measure interfacial curvature from stereo microscope images using level set methods. Curvature, from the perspective of the oil phase, is positive for a concave interface (i.e. water-wet surface) and negative for a convex interface (i.e. oil-wet surface). Thus, shifts in the radius of curvature distribution (i.e. from positive to negative or conversely) are indicative of wettability changes. Both curvature distributions using level-set methods and the Carter method are used to characterize wettability before and after microbial treatment. In preliminary studies aimed at understanding wettability changes due to microbial surface interactions by Bacillus mojavensis JF-2, oil droplets were placed on glass slides suspended in growth media and the resulting contact angle was measured over time. Results showed that a water-wet surface will become more water wet as JF-2 accumulated in

  19. Development of a novel pelletization technique through an extremely high-shear process using a mechanical powder processor to produce high-dose small core granules suitable for film coating. (United States)

    Kondo, Keita; Kato, Aya; Niwa, Toshiyuki


    We established an extremely high-shear melt pelletization technique using a mechanical powder processor to produce high-dose granules smaller than 300 μm with properties suitable for film coating. A mixture of ethenzamide and polyethylene glycol (used as a low-melting binder) at various weight ratios was mechanically treated under various jacket temperatures. When the jacket temperature was set to 50 °C or greater, the product temperature reached the melting point of the binder, resulting in pelletization. The drug powder were pelletized with a small amount of binder to yield pellets of approximately 150 μm with a drug content of more than 90%. The mechanism of melt pelletization through ultrahigh shearing involves a series of nucleation, consolidation, coalescence and breakage stages. The power consumption profile corresponding to each stage in the pelletization revealed that pellets between 75 and 300 μm were effectively obtained at a large power consumption peak. The resultant pellets showed comparative sphericity and smoothness, and higher durability than commercial core granules for film coating. In conclusion, this study demonstrates that the extremely high-shear melt pelletization technique can give drug pellets with desirable properties as core particles for the coating process. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Structure of Wet Specimens in Electron Microscopy (United States)

    Parsons, D. F.


    Discussed are past work and recent advances in the use of electron microscopes for viewing structures immersed in gas and liquid. Improved environmental chambers make it possible to examine wet specimens easily. (Author/RH)

  1. 7 CFR 51.897 - Wet. (United States)


    ... the grapes are wet from moisture from crushed, leaking, or decayed berries or from rain. Grapes which are moist from dew or other moisture condensation such as that resulting from removing grapes from a...

  2. ROE Wet Nitrate Deposition 2011-2013 (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet nitrate deposition in kilograms per hectare from 2011 to 2013. Summary data in this indicator were provided by EPA’s...

  3. ROE Wet Nitrate Deposition 1989-1991 (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet nitrate deposition in kilograms per hectare from 1989 to 1991. Summary data in this indicator were provided by EPA’s...

  4. ROE Wet Sulfate Deposition 2009-2011 (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet sulfate deposition in kilograms per hectare from 2009 to 2011. Summary data in this indicator were provided by EPA’s...

  5. 7 CFR 29.3567 - Wet (W). (United States)


    ... Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO... damage if treated in the customary manner. (See Rule 22, § 29.3623.) (For extremely wet or watered...

  6. 7 CFR 29.2316 - Wet (W). (United States)


    ... Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO... order. Wet applies to any tobacco which is not damaged but which is likely to damage if treated in the...

  7. 7 CFR 29.3077 - Wet (W). (United States)


    ... Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO... doubtful-keeping order. Wet applies to any tobacco which is not damaged but which is likely to damage if...

  8. Wet winter pore pressures in railway embankments


    Briggs, Kevin M; Smethurst, Joel A; Powrie, William; O'Brien, Anthony S


    This paper demonstrates the influence of extreme wet winter weather on pore water pressures within clay fill railway embankments, using field monitoring data and numerical modelling. Piezometer readings taken across the London Underground Ltd network following the wet winter of 2000/2001 were examined, and showed occurrences of hydrostatic pore water pressure within embankments but also many readings below this. A correlation was found between the maximum pore water pressures and the permeabi...

  9. Allergenic Ingredients in Personal Hygiene Wet Wipes. (United States)

    Aschenbeck, Kelly A; Warshaw, Erin M

    Wet wipes are a significant allergen source for anogenital allergic contact dermatitis. The aim of the study was to calculate the frequency of potentially allergenic ingredients in personal hygiene wet wipes. Ingredient lists from brand name and generic personal hygiene wet wipes from 4 large retailers were compiled. In the 54 personal hygiene wet wipes evaluated, a total of 132 ingredients were identified (average of 11.9 ingredients per wipe). The most common ingredients were Aloe barbadensis (77.8%), citric acid (77.8%), fragrance (72.2%), sorbic acid derivatives (63.0%), tocopherol derivatives (63.0%), glycerin (59.3%), phenoxyethanol (55.6%), disodium cocoamphodiacetate (53.7%), disodium ethylenediaminetetraacetic acid (EDTA) (42.6%), propylene glycol (42.6%), iodopropynyl butylcarbamate (40.7%), chamomile extracts (38.9%), sodium benzoate (35.2%), bronopol (22.2%), sodium citrate (22.2%), lanolin derivatives (20.4%), parabens (20.4%), polyethylene glycol derivatives (18.5%), disodium phosphate (16.7%), dimethylol dimethyl hydantoin (DMDM) (14.8%), and cocamidopropyl propylene glycol (PG)-dimonium chloride phosphate (11.1%). Of note, methylisothiazolinone (5.6%) was uncommon; methylchloroisothiazolinone was not identified in the personal hygiene wet wipes examined. There are many potential allergens in personal hygiene wet wipes, especially fragrance and preservatives.

  10. Rainforest-initiated wet season onset over the southern Amazon. (United States)

    Wright, Jonathon S; Fu, Rong; Worden, John R; Chakraborty, Sudip; Clinton, Nicholas E; Risi, Camille; Sun, Ying; Yin, Lei


    Although it is well established that transpiration contributes much of the water for rainfall over Amazonia, it remains unclear whether transpiration helps to drive or merely responds to the seasonal cycle of rainfall. Here, we use multiple independent satellite datasets to show that rainforest transpiration enables an increase of shallow convection that moistens and destabilizes the atmosphere during the initial stages of the dry-to-wet season transition. This shallow convection moisture pump (SCMP) preconditions the atmosphere at the regional scale for a rapid increase in rain-bearing deep convection, which in turn drives moisture convergence and wet season onset 2-3 mo before the arrival of the Intertropical Convergence Zone (ITCZ). Aerosols produced by late dry season biomass burning may alter the efficiency of the SCMP. Our results highlight the mechanisms by which interactions among land surface processes, atmospheric convection, and biomass burning may alter the timing of wet season onset and provide a mechanistic framework for understanding how deforestation extends the dry season and enhances regional vulnerability to drought.

  11. Temperature profile around a basaltic sill intruded into wet sediments (United States)

    Baker, Leslie; Bernard, Andrew; Rember, William C.; Milazzo, Moses; Dundas, Colin M.; Abramov, Oleg; Kestay, Laszlo P.


    The transfer of heat into wet sediments from magmatic intrusions or lava flows is not well constrained from field data. Such field constraints on numerical models of heat transfer could significantly improve our understanding of water–lava interactions. We use experimentally calibrated pollen darkening to measure the temperature profile around a basaltic sill emplaced into wet lakebed sediments. It is well known that, upon heating, initially transparent palynomorphs darken progressively through golden, brown, and black shades before being destroyed; however, this approach to measuring temperature has not been applied to volcanological questions. We collected sediment samples from established Miocene fossil localities at Clarkia, Idaho. Fossils in the sediments include pollen from numerous tree and shrub species. We experimentally calibrated changes in the color of Clarkia sediment pollen and used this calibration to determine sediment temperatures around a Miocene basaltic sill emplaced in the sediments. Results indicated a flat temperature profile above and below the sill, with T > 325 °C within 1 cm of the basalt-sediment contact, near 300 °C at 1–2 cm from the contact, and ~ 250 °C at 1 m from the sill contact. This profile suggests that heat transport in the sediments was hydrothermally rather than conductively controlled. This information will be used to test numerical models of heat transfer in wet sediments on Earth and Mars.

  12. Semi-Automatic Apparatus for Measuring Wetting Properties at High Temperatures

    Directory of Open Access Journals (Sweden)

    Bąkała Marcin


    Full Text Available Determination of the physico-chemical interactions between liquid and solid substances is a key technological factor in many industrial processes in metallurgy, electronics or the aviation industry, where technological processes are based on soldering/brazing technologies. Understanding of the bonding process, reactions between materials and their dynamics enables to make research on new materials and joining technologies, as well as to optimise and compare the existing ones. The paper focuses on a wetting force measurement method and its practical implementation in a laboratory stand – an integrated platform for automatic wetting force measurement at high temperatures. As an example of using the laboratory stand, an analysis of Ag addition to Cu-based brazes, including measurement of the wetting force and the wetting angle, is presented.

  13. Critical wetting of n-alkanes on water; Mouillage critique des alcanes sur l`eau

    Energy Technology Data Exchange (ETDEWEB)

    Ragil, K.


    This study concerns the wetting properties of n-alkanes on water under thermodynamic equilibrium conditions, a problem that is interesting for the petroleum industry as well as for the fundamental understanding of wetting phenomena. An experimental study using ellipsometry reveals that pentane on water undergoes a continuous or critical wetting transition at a temperature equal to 53.1 deg. C. This is the first experimental observation of such a transition, confirming theoretical predictions made on this subject over ten years. This transition is characterized by a continuous and reversible evolution of the thickness of the film of pentane with temperature from a thick (but finite film) to a macroscopic film. The critical wetting transition occurs when the Hamaker constant of the system, which gives the net interaction between the two interfaces bounding the wetting layer of pentane in terms of the van der Waals forces, changes sign. A theoretical approach based on the Cahn-Landau theory, which takes into account long range forces (van der Waals forces), enables us to explain the mechanism of the critical wetting transition and to show that a first-order wetting transition should precede it. Because of their similar dispersive properties, linear alkanes could all be able to show such a succession of transitions. An ellipsometry study performed on a brine/hexane/vapor system confirms that a discontinuous transition from a thin microscopic film to a thick but finite adsorbed film takes place. THis study demonstrates that the wetting of alkanes on water is determined by subtle interplay between short range and long range forces, which can lead to an intermediary state between partial and complete wetting. (author)

  14. Run don't walk: locomotor performance of geckos on wet substrates. (United States)

    Stark, Alyssa Y; Ohlemacher, Jocelyn; Knight, Ashley; Niewiarowski, Peter H


    The gecko adhesive system has been under particular scrutiny for over a decade, as the field has recently attracted attention for its application to bio-inspired design. However, little is known about how the adhesive system behaves in ecologically relevant conditions. Geckos inhabit a variety of environments, many of which are characterized by high temperature, humidity and rain. The van der Waals-based gecko adhesive system should be particularly challenged by wet substrates because water can disrupt the intimate contact necessary for adhesion. While a few previous studies have focused on the clinging ability of geckos on wet substrates, we tested a dynamic performance characteristic, sprint velocity. To better understand how substrate wettability and running orientation affect locomotor performance of multiple species on wet substrates, we measured average sprint velocity of five species of gecko on substrates that were either hydrophilic or intermediately wetting and oriented either vertically or horizontally. Surprisingly, we found no indication that wet substrates impact average sprint velocity over 1 m, and rather, in some species, sprint velocity was increased on wet substrates rather than reduced. When investigating physical characteristics and behavior that may be associated with running on wet substrates, such as total number of stops, slips and wet toes at the completion of a race, we found that there may be habitat-related differences between some species. Our results show that in general, unlike clinging and walking, geckos running along wet substrates suffer no significant loss in locomotor performance over short distances. © 2015. Published by The Company of Biologists Ltd.

  15. Wetting films on chemically patterned surfaces. (United States)

    Karakashev, Stoyan I; Stöckelhuber, Klaus W; Tsekov, Roumen


    The behavior of thin wetting films on chemically patterned surfaces was investigated. The patterning was performed by means of imprinting of micro-grid on methylated glass surface with UV-light (λ=184.8 nm). Thus imprinted image of the grid contained hydrophilic cells and hydrophobic bars on the glass surface. For this aim three different patterns of grids were utilized with small, medium and large size of cells. The experiment showed that the drainage of the wetting aqueous films was not affected by the type of surface patterning. However, after film rupturing in the cases of small and medium cells of the patterned grid the liquid from the wetting film underwent fast self-organization in form of regularly ordered droplets covering completely the cells of the grid. The droplets reduced significantly their size upon time due to evaporation. In the cases of the largest cell grid, a wet spot on the place of the imprinted grid was formed after film rupturing. This wet spot disassembled slowly in time. In addition, formation of a periodical zigzag three-phase contact line (TPCL) was observed. This is a first study from the planned series of studies on this topic. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Evaporation from rain-wetted forest in relation to canopy wetness, canopy cover, and net radiation

    NARCIS (Netherlands)

    Klaassen, W.


    Evaporation from wet canopies is commonly calculated using E-PM, the Penman-Monteith equation with zero surface resistance. However, several observations show a lower evaporation from rain-wetted forest. Possible causes for the difference between E-PM and experiments are evaluated to provide rules

  17. Advanced methods for the treatment of organic aqueous wastes: wet air oxidation and wet peroxide oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Debellefontaine, Hubert; Chakchouk, Mehrez; Foussard, Jean Noel [Institut National des Sciences Appliquees (INSA), 31 - Toulouse (France). Dept. de Genie des Procedes Industriels; Tissot, Daniel; Striolo, Phillipe [IDE Environnement S.A., Toulouse (France)


    There is a growing concern about the problems of wastes elimination. Various oxidation techniques are suited for elimination of organic aqueous wastes, however, because of the environmental drawbacks of incineration, liquid phase oxidation should be preferred. `Wet Air Oxidation` and `Wet Peroxide Oxidation`are alternative processes which are discussed in this paper. 17 refs., 13 figs., 4 tabs.

  18. Development and Optimization of a Wet Granulation Process at Elevated Temperature for a Poorly Compactible Drug Using Twin Screw Extruder for Continuous Manufacturing. (United States)

    Meena, Anuprabha K; Desai, Divyakant; Serajuddin, Abu T M


    The objective of this study was to enhance tabletability of a poorly compactible drug, acetaminophen, by wet granulation using twin screw extruder at high temperature. It was desired that there would be minimum amounts of excipients used and the granules obtained after extrusion would be dry and fall within a size range suitable for tableting without any further processing. Mixtures of acetaminophen (95%) with binders (5% povidone or partially pregelatinized starch) were wet granulated through twin screw extruder at 70°C by adding 7% w/w water. The process had a short granulation time (90% granules in the size range of 125 to 1000 μm (granules were compressed by adding 1% disintegrant and 0.5% lubricant extragranularly, tablets produced (93.6% drug load) had good mechanical strength having hardness >1.7 MPa, which was superior to that of tablets prepared by conventional high shear wet granulation. As the granules could be extruded continuously and did not require drying and milling, the method was amenable to continuous processing. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  19. Teknologi penyamakan kulit wet blue buaya

    Directory of Open Access Journals (Sweden)

    Bambang Oetojo


    Full Text Available For this study it was used 12 pieces of grain salted crocodile skin of 11 up to 14 inch width. All of the crocodile skin were process up to pickling with the same way. Furthermore pickled crocodile skins were process up to pickling with the same way. Furthermore pickled crocodile skins and was done twice. The wet blue output from the research was visual investigated for the coulor using staning scale method. For comparition it was used pickled crocodile skins. Statistical analysis pints out that there is unsignify difference (P<0.05 the influence of the used of basic chrome sulphate to the colour of wet blue crocodile skins. Practical meaning of the research is, for tanning of crocodile skins to the wet blue, it is used 1.5% basic chromium sulphate.

  20. Handling of wet residues in industry

    DEFF Research Database (Denmark)

    Villanueva, Alejandro

    to water bodies and uses of such bodies, distance to available agricultural land, characteristics of the local wastewater treatment plant, local and national legislation, or availability of subsidies. This study uses as example the geographical, legislative, economic and social boundary conditions......In countries with high prices of fresh water use and wastewater discharge, water recycling has become an alternative to traditional water consumption and discharge for industries with water-based processes. Industrial water recycling means in many cases that water has to be treated and cleaned......, to remove from it the substances which presence impedes reusing the water. These substances accumulate in a by-product called wet residue. An integral part of water recycling projects in the industry is the handling and disposal of the wet residues generated. The treatment, utilisation and disposal of wet...


    Energy Technology Data Exchange (ETDEWEB)

    Jill S. Buckley; Norman R. Morrow; Chris Palmer; Purnendu K. Dasgupta


    The questions of reservoir wettability have been approached in this project from three directions. First, we have studied the properties of crude oils that contribute to wetting alteration in a reservoir. A database of more than 150 different crude oil samples has been established to facilitate examination of the relationships between crude oil chemical and physical properties and their influence on reservoir wetting. In the course of this work an improved SARA analysis technique was developed and major advances were made in understanding asphaltene stability including development of a thermodynamic Asphaltene Solubility Model (ASM) and empirical methods for predicting the onset of instability. The CO-Wet database is a resource that will be used to guide wettability research in the future. The second approach is to study crude oil/brine/rock interactions on smooth surfaces. Contact angle measurements were made under controlled conditions on mica surfaces that had been exposed to many of the oils in the CO-Wet database. With this wealth of data, statistical tests can now be used to examine the relationships between crude oil properties and the tendencies of those oils to alter wetting. Traditionally, contact angles have been used as the primary wetting assessment tool on smooth surfaces. A new technique has been developed using an atomic forces microscope that adds a new dimension to the ability to characterize oil-treated surfaces. Ultimately we aim to understand wetting in porous media, the focus of the third approach taken in this project. Using oils from the CO-Wet database, experimental advances have been made in scaling the rate of imbibition, a sensitive measure of core wetting. Application of the scaling group to mixed-wet systems has been demonstrated for a range of core conditions. Investigations of imbibition in gas/liquid systems provided the motivation for theoretical advances as well. As a result of this project we have many new tools for studying

  2. Sphere impact and penetration into wet sand

    KAUST Repository

    Marston, J. O.


    We present experimental results for the penetration of a solid sphere when released onto wet sand. We show, by measuring the final penetration depth, that the cohesion induced by the water can result in either a deeper or shallower penetration for a given release height compared to dry granular material. Thus the presence of water can either lubricate or stiffen the granular material. By assuming the shear rate is proportional to the impact velocity and using the depth-averaged stopping force in calculating the shear stress, we derive effective viscosities for the wet granular materials.

  3. Evaporation and wetted area of single droplets on waxy and hairy leaf surfaces. (United States)

    Zhu, H; Yu, Y; Ozkan, H E; Derksen, R C; Krause, C R


    Understanding the evaporation of pesticide droplets and wetting of Leaf surfaces can increase foliar application efficiency and reduce pesticide use. Evaporation time and wetted area of single pesticide droplets on hairy and waxy geranium leaf surfaces were measured under the controlled conditions for five droplet sizes and three relative humidities. The sprays used to form droplets included water, a nonionic colloidal polymer drift retardant, an alkyl polyoxyethylene surfactant, and an insecticide. Adding the surfactant into spray mixtures greatly increased droplet wetted area on the surfaces while droplet evaporation time was greatly reduced. Adding the drift retardant into spray mixture slightly increased the droplet evaporation time and the wetted area. Also, droplets had Longer evaporation times on waxy leaves than on hairy leaves for all droplet diameters and all relative humidity conditions. Increasing relative humidity could increase the droplet evaporation time greatly but did not change the the wetted area. The droplet evaporation time and wetted area increased exponentially as the droplet size increased. Therefore, droplet size, surface characteristics of the target, relative humidity, and chemical composition of the spray mixtures (water alone, pesticide, additives) should be included as important factors that affect the efficacy and efficiency of pesticide applications.

  4. Catalytic gasification of dry and wet biomass

    NARCIS (Netherlands)

    van Rossum, G.; Potic, B.; Kersten, Sascha R.A.; van Swaaij, Willibrordus Petrus Maria


    Catalytic gasification of dry biomass and of wet biomass streams in hot compressed water are reviewed and discussed as potential technologies for the production of synthesis gas, hydrogen- and methane-rich gas. Next to literature data also new experimental results from our laboratory on catalytic

  5. Microwave moisture sensing of wet bales (United States)

    Sensing of moisture in very wet lint bales is unique due to the fact that moisture distribution is typically non-uniform and can in some instances be highly localized. This issue is even further complicated by the use of a sensor that reads only a portion of the bale and/or with a sensor that provid...

  6. Verification of wet blasting decontamination technology

    International Nuclear Information System (INIS)

    Matsubara, Sachito; Murayama, Kazunari; Yoshida, Hirohisa; Igei, Shigemitsu; Izumida, Tatsuo


    Macoho Co., Ltd. participated in the projects of 'Decontamination Verification Test FY 2011 by the Ministry of the Environment' and 'Decontamination Verification Test FY 2011 by the Cabinet Office.' And we tested verification to use a wet blasting technology for decontamination of rubble and roads contaminated by the accident of Fukushima Daiichi Nuclear Power Plant of the Tokyo Electric Power Company. As a results of the verification test, the wet blasting decontamination technology showed that a decontamination rate became 60-80% for concrete paving, interlocking, dense-grated asphalt pavement when applied to the decontamination of the road. When it was applied to rubble decontamination, a decontamination rate was 50-60% for gravel and approximately 90% for concrete and wood. It was thought that Cs-134 and Cs-137 attached to the fine sludge scraped off from a decontamination object and the sludge was found to be separated from abrasives by wet cyclene classification: the activity concentration of the abrasives is 1/30 or less than the sludge. The result shows that the abrasives can be reused without problems when the wet blasting decontamination technology is used. (author)

  7. Aqueous Wetting Films on Fused Quartz. (United States)

    Mazzoco; Wayner


    Using an image analyzing interferometer, IAI, the interfacial characteristics of an isothermal constrained vapor bubble, CVB, in a quartz cuvette were studied as a precursor to heat transfer research. The effects of pH and electrolyte concentration on the meniscus properties (curvature and adsorbed film thickness) and the stability of the aqueous wetting films were evaluated. The surface potential in the electric double layer was a function of the cleaning and hydroxylation of the quartz surface. The disjoining pressure isotherm for pure water was very close to that predicted by the Langmuir equation. For aqueous solutions of moderate electrolyte concentration, the Gouy-Chapman theory provided a good representation of the electrostatic effects in the film. The effect of temperature on the film properties of aqueous solutions and pure water was also evaluated: The meniscus curvature decreased with increasing temperature, while Marangoni effects, intermolecular forces, and local evaporation and condensation enhanced waves on the adsorbed film layer. Pure water wetting films were mechanically metastable, breaking into droplets and very thin films (less than 10 nm) after a few hours. Aqueous wetting films with pH 12.4 proved to be stable during a test of several months, even when subjected to temperature and mechanical perturbations. The mechanical stability of wetting films can explain the reported differences between the critical heat fluxes of pure water and aqueous solutions. The IAI-CVB technique is a simple and versatile experimental technique for studying the characteristics of interfacial systems. Copyright 1999 Academic Press.

  8. Wet steam turbines for CANDU-Reactors

    International Nuclear Information System (INIS)

    Westmacott, C.H.L.


    The technical characteristics of 4 wet steam turbine aggregates used in the Pickering nuclear power station are reported on along with operational experience. So far, the general experience was positive. Furthermore, plans are mentioned to use this type of turbines in other CANDU reactors. (UA) [de

  9. Characteristics of wetting temperature during spray cooling

    International Nuclear Information System (INIS)

    Mitsutake, Yuichi; Monde, Masanori; Hidaka, Shinichirou


    An experimental study has been done to elucidate the effects of mass flux and subcooling of liquid and thermal properties of solid on the wetting temperature during cooling of a hot block with spray. A water spray was impinged at one of the end surfaces of a cylindrical block initially heated at 400 or 500degC. The experimental condition was mass fluxes G=1-9 kg/m 2 s and degrees of subcooling ΔT sub =20, 50, 80 K. Three blocks of copper, brass and carbon steel were prepared. During spray cooling internal block temperature distribution and sputtering sound pressure level were recorded and the surface temperature and heat flux were evaluated with 2D inverse heat conducting analysis. Cooling process on cooling curves is divided into four regimes categorized by change in a flow situation and the sound level. The wetting temperature defined as the wall temperature at a minimum heat flux point was measured over an extensive experimental range. The wetting wall temperature was correlated well with the parameter of GΔT sub . The wetting wall temperature increases as GΔT sub increases and reaches a constant value depending on the material of the surface at higher region of GΔT sub . (author)

  10. Wet adhesion and adhesive locomotion of snails on anti-adhesive non-wetting surfaces.

    Directory of Open Access Journals (Sweden)

    Neil J Shirtcliffe

    Full Text Available Creating surfaces capable of resisting liquid-mediated adhesion is extremely difficult due to the strong capillary forces that exist between surfaces. Land snails use this to adhere to and traverse across almost any type of solid surface of any orientation (horizontal, vertical or inverted, texture (smooth, rough or granular or wetting property (hydrophilic or hydrophobic via a layer of mucus. However, the wetting properties that enable snails to generate strong temporary attachment and the effectiveness of this adhesive locomotion on modern super-slippy superhydrophobic surfaces are unclear. Here we report that snail adhesion overcomes a wide range of these microscale and nanoscale topographically structured non-stick surfaces. For the one surface which we found to be snail resistant, we show that the effect is correlated with the wetting response of the surface to a weak surfactant. Our results elucidate some critical wetting factors for the design of anti-adhesive and bio-adhesion resistant surfaces.

  11. Wet adhesion and adhesive locomotion of snails on anti-adhesive non-wetting surfaces. (United States)

    Shirtcliffe, Neil J; McHale, Glen; Newton, Michael I


    Creating surfaces capable of resisting liquid-mediated adhesion is extremely difficult due to the strong capillary forces that exist between surfaces. Land snails use this to adhere to and traverse across almost any type of solid surface of any orientation (horizontal, vertical or inverted), texture (smooth, rough or granular) or wetting property (hydrophilic or hydrophobic) via a layer of mucus. However, the wetting properties that enable snails to generate strong temporary attachment and the effectiveness of this adhesive locomotion on modern super-slippy superhydrophobic surfaces are unclear. Here we report that snail adhesion overcomes a wide range of these microscale and nanoscale topographically structured non-stick surfaces. For the one surface which we found to be snail resistant, we show that the effect is correlated with the wetting response of the surface to a weak surfactant. Our results elucidate some critical wetting factors for the design of anti-adhesive and bio-adhesion resistant surfaces.

  12. µPlasma patterning and inkjet printing to enhance localized wetting and mixing behaviour

    NARCIS (Netherlands)

    van Dongen, Martinus Henricus Adrianus; van Dongen, Martinus Henricus Adrianus


    In the development of applications for printed electronics, the interaction of fluids with substrates is of great importance. Control and understanding of the wetting behaviour of fluids on substrates, as well as fluid-fluid interaction on the substrate is necessary to develop new applications. This

  13. Patterns of primary succession of native and introduced plants in lowland wet forests in eastern Hawaii (United States)

    Naupaka Zimmerman; Flint 1 Hughes; Patrick Hart; Heather Kalei Chang; David Perez; Ryan Kaipoalohaakala Like; Rebecca. Ostertag


    The majority of Hawaii's lowland wet forests no longer exist, with many of the last remaining patches found on the eastern, windward sides of the largest islands. To better understand successional patterns and invasion in these native systems, we quantified basal area (BA) and densities of woody species and understory cover at nine sites in the Puna district on...

  14. A wet-chemical approach to perovskite and fluorite-type nanoceramics: synthesis and processing

    NARCIS (Netherlands)

    Veldhuis, Sjoerd


    In thesis the low-temperature, wet-chemical approach to various functional inorganic oxide materials is described. The main focus of this research is to control the material’s synthesis from liquid precursor to metal oxide powder or thin film; while understanding its formation mechanism. In

  15. Characterization of pavement texture by means of height difference correlation and relation to wet skid resistance

    Directory of Open Access Journals (Sweden)

    Stefan Torbruegge


    We deduce within this article the correlation between classical surface roughness parameters and the parameter set of self-affine surfaces. These parameters allow for a detailed understanding of the relationship between pavement texture and its wet skid resistance. We present wet skid resistance measurements with the British pendulum and a linear friction tester device on different pavement textures. We demonstrate that the so-called estimated texture depth does not correlate to the surface skid resistance measured with the British pendulum. Finally, we deduce a dependency of wet skid resistance on pavement texture which is supported by current models for hysteresis friction.

  16. Dynamics of Wetting of Ultra Hydrophobic Surfaces (United States)

    Mohammad Karim, Alireza; Kim, Jeong-Hyun; Rothstein, Jonathan; Kavehpour, Pirouz; Mechanical and Industrial Engineering, University of Massachusetts, Amherst Collaboration


    Controlling the surface wettability of hydrophobic and super hydrophobic surfaces has extensive industrial applications ranging from coating, painting and printing technology and waterproof clothing to efficiency increase in power and water plants. This requires enhancing the knowledge about the dynamics of wetting on these hydrophobic surfaces. We have done experimental investigation on the dynamics of wetting on hydrophobic surfaces by looking deeply in to the dependency of the dynamic contact angles both advancing and receding on the velocity of the three-phase boundary (Solid/Liquid/Gas interface) using the Wilhelmy plate method with different ultra-hydrophobic surfaces. Several fluids with different surface tension and viscosity are used to study the effect of physical properties of liquids on the governing laws.

  17. Avoided critical behavior in dynamically forced wetting. (United States)

    Snoeijer, Jacco H; Delon, Giles; Fermigier, Marc; Andreotti, Bruno


    A solid object can be coated by a nonwetting liquid since a receding contact line cannot exceed a critical speed. In this Letter we study the dynamical wetting transition at which a liquid film gets deposited by withdrawing a vertical plate out of a liquid reservoir. It has recently been predicted that this wetting transition is critical with diverging time scales and coincides with the disappearance of stationary menisci. We demonstrate experimentally and theoretically that the transition is due to the formation of a solitary wave, well below the critical point. As a consequence, relaxation times remain finite at threshold. The structure of the liquid deposited on the plate involves a capillary ridge that does not trivially match the Landau-Levich film.

  18. Wet precipitators for sulphuric acid plants

    International Nuclear Information System (INIS)

    Ojanpera, R.O.


    Both the service requirements and design construction details have changed considerably in recent years for wet electrostatic precipitators as used for gas cleaning ahead of metallurgical sulphuric acid plants. Increased concern over acid quality has resulted in more emphasis on dust efficiencies compared to collection of acid mist. Also, higher static operating pressures have caused large structural loads on casing and internal components. In this paper these two issues are addressed in the following ways: Recognition that all dusts do not collect similarly. The mechanism by which various dusts collect affect the design of the entire wet gas cleaning system. Use of both traditional and newer materials of construction to accommodate the higher design pressures while still maintaining corrosion resistance

  19. The unusual wet summer (July) of 2014 in Southern Europe (United States)

    Ratna, Satyaban B.; Ratnam, J. V.; Behera, Swadhin K.; Cherchi, Annalisa; Wang, Wanqiu; Yamagata, Toshio


    Southern Europe (Italy and the surrounding countries) experienced an unusual wet summer in 2014. The monthly rainfall in July 2014 was 84% above (more than three standard deviation) normal with respect to the 1982-2013 July climatology. The heavy rainfall damaged agriculture, and affected tourism and overall economy of the region. In this study, we tried to understand the physical mechanisms responsible for such abnormal weather by using model and observed datasets. The anomalously high precipitation over Italy is found to be associated with the positive sea surface temperature (SST) and convective anomalies in the tropical Pacific through the atmospheric teleconnection. Rossby wave activity flux at upper levels shows an anomalous tropospheric quasi-stationary Rossby wave from the Pacific with an anomalous cyclonic phase over southern Europe. This anomalous cyclonic circulation is barotropic in nature and seen extending to lower atmospheric levels, weakening the seasonal high and causing heavy precipitation over the Southern Europe. The hypothesis is verified using the National Centers for Environmental Prediction (NCEP) coupled forecast system model (CFSv2) seasonal forecasts. It is found that two-month lead forecast of CFSv2 was able to capture the wet summer event of 2014 over Southern Europe. The teleconnection pattern from Pacific to Southern Europe was also forecasted realistically by the CFSv2 system.

  20. Predictive modeling of reactive wetting and metal joining.

    Energy Technology Data Exchange (ETDEWEB)

    van Swol, Frank B.


    The performance, reproducibility and reliability of metal joints are complex functions of the detailed history of physical processes involved in their creation. Prediction and control of these processes constitutes an intrinsically challenging multi-physics problem involving heating and melting a metal alloy and reactive wetting. Understanding this process requires coupling strong molecularscale chemistry at the interface with microscopic (diffusion) and macroscopic mass transport (flow) inside the liquid followed by subsequent cooling and solidification of the new metal mixture. The final joint displays compositional heterogeneity and its resulting microstructure largely determines the success or failure of the entire component. At present there exists no computational tool at Sandia that can predict the formation and success of a braze joint, as current capabilities lack the ability to capture surface/interface reactions and their effect on interface properties. This situation precludes us from implementing a proactive strategy to deal with joining problems. Here, we describe what is needed to arrive at a predictive modeling and simulation capability for multicomponent metals with complicated phase diagrams for melting and solidification, incorporating dissolutive and composition-dependent wetting.

  1. Making Activated Carbon by Wet Pressurized Pyrolysis (United States)

    Fisher, John W.; Pisharody, Suresh; Wignarajah, K.; Moran, Mark


    A wet pressurized pyrolysis (wet carbonization) process has been invented as a means of producing activated carbon from a wide variety of inedible biomass consisting principally of plant wastes. The principal intended use of this activated carbon is room-temperature adsorption of pollutant gases from cooled incinerator exhaust streams. Activated carbon is highly porous and has a large surface area. The surface area depends strongly on the raw material and the production process. Coconut shells and bituminous coal are the primary raw materials that, until now, were converted into activated carbon of commercially acceptable quality by use of traditional production processes that involve activation by use of steam or carbon dioxide. In the wet pressurized pyrolysis process, the plant material is subjected to high pressure and temperature in an aqueous medium in the absence of oxygen for a specified amount of time to break carbon-oxygen bonds in the organic material and modify the structure of the material to obtain large surface area. Plant materials that have been used in demonstrations of the process include inedible parts of wheat, rice, potato, soybean, and tomato plants. The raw plant material is ground and mixed with a specified proportion of water. The mixture is placed in a stirred autoclave, wherein it is pyrolized at a temperature between 450 and 590 F (approximately between 230 and 310 C) and a pressure between 1 and 1.4 kpsi (approximately between 7 and 10 MPa) for a time between 5 minutes and 1 hour. The solid fraction remaining after wet carbonization is dried, then activated at a temperature of 500 F (260 C) in nitrogen gas. The activated carbon thus produced is comparable to commercial activated carbon. It can be used to adsorb oxides of sulfur, oxides of nitrogen, and trace amounts of hydrocarbons, any or all of which can be present in flue gas. Alternatively, the dried solid fraction can be used, even without the activation treatment, to absorb

  2. Exposure to wet work in working Australians. (United States)

    Keegel, Tessa G; Nixon, Rosemary L; LaMontagne, Anthony D


    The Australian National Hazard Exposure Worker Surveillance (NHEWS) Survey 2008 was a cross-sectional survey undertaken by Safe Work Australia to inform the development of exposure prevention initiatives for occupational disease. This is a descriptive study of workplace exposures. To assess the occupational and demographic characteristics of workers reporting exposure to wet work. Computer-assisted telephone interviews were conducted with 4500 workers. Two wet work exposure outcomes (frequent washing of hands and duration of time spent at work with the hands immersed in liquids) were analysed. The response rate for the study was 42.3%. For hand-washing, 9.8% [95% confidence interval (CI) 8.9-10.7] reported washing their hands more than 20 times per day. For immersion of hands in liquids, 4.5% (95% CI 3.9-5.1) reported immersion for more than 2 hr per day. Females were more likely to report exposure to frequent hand-washing than males [odds ratio (OR) 1.97, 95% CI 1.49-2.61]. Workers in the lowest occupational skill level jobs were more likely to report increased exposure to hands immersed in liquids than those in the highest (OR 6.41, 95% CI 3.78-10.88). Workers reporting skin exposure to chemicals were more likely to report exposure to hand-washing (OR 3.68, 95% CI 2.91-4.66) and immersion of the hands in liquids (OR 4.09, 95% CI 2.92-5.74). Specific groups of workers reported high levels of exposure to wet work. There were differences between the profiles of workers reporting frequent hand-washing and workers reporting increased duration of exposure to hands immersed in liquids. We also found a high correlation between wet work and chemical exposure. © 2011 John Wiley & Sons A/S.

  3. Wet flue gas desulphurization and new fuels

    Energy Technology Data Exchange (ETDEWEB)

    Kiil, S.; Dam-Johansen, K.; Michelsen, M.L.


    This thesis describes experimental and theoretical investigations of wet flue gas desulphurization (FGD). A review of the current knowledge of the various rate determining steps in wet FDG plants is presented. The mechanism underlying the rate of dissolution of finely grained limestone particles was examined in a laboratory batch apparatus using acid titration. Three Danish limestones of different origin were tested. A transient, mass transport controlled, mathematical model was developed to describe the dissolution process. Model predictions were found to be qualitatively in good agreement with experimental data. Empirical correlations for the dimensionless mass transfer coefficients in a pilot plant (falling-film column) were determined. The presence of inert particles in the liquid phase was found to decrease the rate of gas phase mass transport with up to 15%, though the effect could not be correlated. A detailed model for a wet FGD pilot plant, based on the falling film principle, was developed. All important rate determining steps, absorption of SO{sub 2}, oxidation of HSO{sub 3}{sup -}, dissolution of limestone, and crystallisation of gypsum were included. Model predictions were compared to experimental data such as gas phase concentration profiles of SO{sub 2}, slurry pH-profiles, solids contents of slurry, liquid phase concentrations, and residual limestone in the gypsum. The possibility of co-firing straw and coal was investigated in a full-scale power plant. No effects on the overall performance of the wet FGD plant were observed, though laboratory experiments with fine dust and fly ash from the full-scale experiments showed a decrease in limestone reactivity. (EG) EFP-95. 45 refs.; Also ph.d. thesis of Soeren Kiil

  4. Mixing and transport during pharmaceutical twin-screw wet granulation: experimental analysis via chemical imaging. (United States)

    Kumar, Ashish; Vercruysse, Jurgen; Toiviainen, Maunu; Panouillot, Pierre-Emmanuel; Juuti, Mikko; Vanhoorne, Valérie; Vervaet, Chris; Remon, Jean Paul; Gernaey, Krist V; De Beer, Thomas; Nopens, Ingmar


    Twin-screw granulation is a promising continuous alternative for traditional batch high shear wet granulation (HSWG). The extent of HSWG in a twin screw granulator (TSG) is greatly governed by the residence time of the granulation materials in the TSG and degree of mixing. In order to determine the residence time distribution (RTD) and mixing in TSG, mostly visual observation and particle tracking methods are used, which are either inaccurate and difficult for short RTD, or provide an RTD only for a finite number of preferential tracer paths. In this study, near infrared chemical imaging, which is more accurate and provides a complete RTD, was used. The impact of changes in material throughput (10-17 kg/h), screw speed (500-900 rpm), number of kneading discs (2-12) and stagger angle (30-90°) on the RTD and axial mixing of the material was characterised. The experimental RTD curves were used to calculate the mean residence time, mean centred variance and the Péclet number to determine the axial mixing and predominance of convective over dispersive transport. The results showed that screw speed is the most influential parameter in terms of RTD and axial mixing in the TSG and established a significant interaction between screw design parameters (number and stagger angle of kneading discs) and the process parameters (material throughput and number of kneading discs). The results of the study will allow the development and validation of a transport model capable of predicting the RTD and macro-mixing in the TSG. These can later be coupled with a population balance model in order to predict granulation yields in a TSG more accurately. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Characterization of Polymer Surfaces by the Use of Different Wetting Theories Regarding Acid-Base Properties

    Directory of Open Access Journals (Sweden)

    Eduard Kraus


    Full Text Available The existing wetting methods for the determination of acid-base properties on solid surfaces are discussed. Striving for a better understanding of the adhesive polymer interactions in adhesively joined polymers, the methods of Berger and van Oss-Chaudhury-Good were found as the most suitable methods for the investigation of wetting on solid polymer surfaces. Methods of nonlinear systems by Della Volpe and Siboni were adapted and evaluated on plastic surfaces. In the context of these investigations various data of the surface free energy as well as its components have been identified for a number of polymer surfaces by application of spatial equation solutions.

  6. Study of polycaprolactone wet electrospinning process

    Directory of Open Access Journals (Sweden)

    E. Kostakova


    Full Text Available Wet electrospinning is a useful method for 3-dimensional structure control of nanofibrous materials. This innovative technology uses a liquid collector instead of the metal one commonly used for standard electrospinning. The article compares the internal structural features of polycaprolactone (PCL nanofibrous materials prepared by both technologies. We analyze the influence of different water/ethanol compositions used as a liquid collector on the morphology of the resultant polycaprolactone nanofibrous materials. Scanning electron micro-photographs have revealed a bimodal structure in the wet electrospun materials composed of micro and nanofibers uniformly distributed across the sample bulk. We have shown that the full-faced, twofold fiber distribution is due to the solvent composition and is induced and enhanced by increasing the ethanol weight ratio. Moreover, the comparison of fibrous layers morphology obtained by wet and dry spinning have revealed that beads that frequently appeared in dry spun materials are created by Plateau-Rayleigh instability of the fraction of thicker fibers. Theoretical conditions for spontaneous and complete immersion of cylindrical fibers into a liquid collector are also derived here.

  7. Wetting, superhydrophobicity, and icephobicity in biomimetic composite materials (United States)

    Hejazi, Vahid

    data are collected in terms of oleophobicity especially when underwater applications are of interest. We develop models for four-phase rough interface of underwater oleophobicity and develop a novel approach to predict the CA of organic liquid on the rough surfaces immersed in water. We investigate wetting transition on a patterned surface in underwater systems, using a phase field model. We demonstrated that roughening on an immersed solid surface can drive the transition from Wenzel to Cassie-Baxter state. This discovery improves our understanding of underwater systems and their surface interactions during the wetting phenomenon and can be applied for the development of underwater oil-repellent materials which are of interest for various applications in the water industry, and marine devices. In chapter five, we experimentally and theoretically investigate the icephobicity of composite materials. A novel comprehensive definition of icephobicity, broad enough to cover a variety of situations including low adhesion strength, delayed ice crystallization, and bouncing is determined. Wetting behavior and ice adhesion properties of various samples are theoretically and experimentally compared. We conclude superhydrophobic surfaces are not necessarily icephobic. The models are tested against the experimental data to verify the good agreement between them. The models can be used for the design of novel superhydrophobic, oleophobic, omniphobic and icephobic composite materials. Finally we conclude that creating surface micro/nanostructures using mechanical abrasion or chemical etching as well as applying low energy materials are the most simple, inexpensive, and durable techniques to create superhydrophobic, oleophobic, and icephobic materials.

  8. Characteristics of wet work in the cleaning industry

    NARCIS (Netherlands)

    Jungbauer, F H W; Van Der Harst, J J; Schuttelaar, M L; Groothoff, J W; Coenraads, P J

    Wet work is the main cause of occupational contact dermatitis in the cleaning industry. Dermatologists and occupational physicians need to base their primary and secondary prevention for workers in the cleaning industry on the characteristics of wet work exposures. We quantified the burden of wet

  9. Experimental and Theoretical Investigations of Wet Flue Gas Desulphurisation

    DEFF Research Database (Denmark)

    Kiil, Søren

    This thesis describes experimental and theoretical investigations of wet flue gas desulphurisa-tion (FGD). A review of the current knowledge of the various rate determining steps in wet FGD plants is presented. The experimental work covers laboratory studies as well as pilot- and full-scale exper...... and mass transport phenomena in wet FGD plants....

  10. Artificial wetting of buffer material. Small scale

    International Nuclear Information System (INIS)

    Holt, E.; Marjavaara, P.; Loeija, M.


    The purpose of this work was to investigate the swelling behaviour of artificially wetted highly compacted bentonite buffer blocks used in deposition holes for nuclear waste containment. The target was to make a preliminary study if homogeneous and rapid swelling of the bentonite is possible to achieve in the gap between the buffer and the rock wall of the deposition hole by artificial wetting. It is expected that the thermal, mechanical, chemical and hydraulic properties of the whole deposition system are better when the bentonite-rock gap is closed. In practice it is desirable that the bentonite material has a volume increase sufficient enough to create pressure against the rock surface. Uniform bentonite buffer swelling into the gap would prevent rock scaling while lowering the risks of bentonite piping and erosion due to potential water flow. In this work, two preliminary sets of tests were done on bentonite block swelling and water filtration through pellets. The majority of work was within the primary tests, where bentonite blocks were confined in a test chamber and swelling was induced by artificial wetting. Water was poured directly into the gap from the top, without the aid of pipes or pressure. After the initial watering, no additional water or moisture was made available for the system during the test duration. The resulting bentonite swelling pressure in both the radial and vertical directions was measured over time. 13 different test scenarios were investigated, including: varying block size of 10 cm height disks or 30 cm blocks, eccentric aligned blocks with gap sizes of 5 and 45 mm, gap sizes of 25 mm or 50 mm, using gap filling with pellets or granular in combined with water, free upward swelling or confinement, addition of water at varying rates, and longer term test duration. In some cases, video images were taken during the swelling, to get an indication of the time until the gap was sealed. After the wetting tests, material properties of the

  11. Multimodal approach to characterization of hydrophilic matrices manufactured by wet and dry granulation or direct compression methods. (United States)

    Kulinowski, Piotr; Woyna-Orlewicz, Krzysztof; Obrał, Jadwiga; Rappen, Gerd-Martin; Haznar-Garbacz, Dorota; Węglarz, Władysław P; Jachowicz, Renata; Wyszogrodzka, Gabriela; Klaja, Jolanta; Dorożyński, Przemysław P


    The purpose of the research was to investigate the effect of the manufacturing process of the controlled release hydrophilic matrix tablets on their hydration behavior, internal structure and drug release. Direct compression (DC) quetiapine hemifumarate matrices and matrices made of powders obtained by dry granulation (DG) and high shear wet granulation (HS) were prepared. They had the same quantitative composition and they were evaluated using X-ray microtomography, magnetic resonance imaging and biorelevant stress test dissolution. Principal results concerned matrices after 2 h of hydration: (i) layered structure of the DC and DG hydrated tablets with magnetic resonance image intensity decreasing towards the center of the matrix was observed, while in HS matrices layer of lower intensity appeared in the middle of hydrated part; (ii) the DC and DG tablets retained their core and consequently exhibited higher resistance to the physiological stresses during simulation of small intestinal passage than HS formulation. Comparing to DC, HS granulation changed properties of the matrix in terms of hydration pattern and resistance to stress in biorelevant dissolution apparatus. Dry granulation did not change these properties-similar hydration pattern and dissolution in biorelevant conditions were observed for DC and DG matrices. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Modeling and analysis of wet friction clutch engagement dynamics (United States)

    Iqbal, Shoaib; Al-Bender, Farid; Ompusunggu, Agusmian P.; Pluymers, Bert; Desmet, Wim


    In recent years, there has been a significant increase in the usage of wet-friction clutches. Presently researchers across the globe are involved in improving the performance and lifetime of clutches through testing and simulation. To understand the clutch vibrational and dynamical behavior, an SAE#2 test setup mathematical model based on extended reset-integrator friction model is developed in this paper. In order to take into account the different phases of fluid lubrication during engagement cycle, the model includes the experimentally determined Stribeck function. In addition the model considers the viscous effect and the delay in the actuation pressure signal. The model is validated with the experiments performed on the SAE#2 test setup in both time and frequency domains. By analyzing the set of experimental results, we confirmed that the amplitude of shudder vibration is independent of the amplitude of applied contact pressure fluctuation.

  13. Application of In-line Focused Beam Reflectance Measurement to Brivanib Alaninate Wet Granulation Process to Enable Scale-up and Attribute-based Monitoring and Control Strategies. (United States)

    Narang, Ajit S; Stevens, Timothy; Macias, Kevin; Paruchuri, Srinivasa; Gao, Zhihui; Badawy, Sherif


    Application of in-line real-time process monitoring using a process analytical technology for granule size distribution can enable quality-by-design development of a drug product and enable attribute-based monitoring and control strategies. In this study, an in-line laser focused beam reflectance measurement (FBRM) C35 probe was used to investigate the effect of formulation and process parameters on the granule growth profile over time during the high shear wet granulation of a high drug load formulation of brivanib alaninate. The probe quantitatively captured changes in the granule chord length distribution (CLD) with the progress of granulation and delineated the impact of water concentration used during granulation. The results correlated well with offline particle size distribution measured by nested sieve analyses. An end point indication algorithm was developed that was able to successfully track the process time needed to reach the target CLD. Testing of the brivanib alaninate granulation through 25-fold scale-up of the batch process indicated that the FBRM CLD profile can provide a scale-independent granule attribute-based process fingerprint. These studies highlight the ability of FBRM to quantitate a granule attribute of interest during wet granulation that can be used as an attribute-based scale-up and process monitoring and control parameter. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  14. Uncertainty associated with convective wet removal of entrained aerosols in a global climate model

    Directory of Open Access Journals (Sweden)

    B. Croft


    scheme since nearly all entrained accumulation and coarse mode aerosols are assumed to be cloud-droplet borne or ice-crystal borne, and evaporation due to the Bergeron-Findeisen process is neglected.

    The simulated convective wet scavenging of entrained accumulation and coarse mode aerosols has feedbacks on new particle formation and the number of Aitken mode aerosols, which control stratiform and convective cloud droplet number concentrations and yield precipitation changes in the ECHAM5-HAM model. However, the geographic distribution of aerosol annual mean convective wet deposition change in the model is driven by changes to the assumptions regarding the scavenging of aerosols entrained above cloud bases rather than by precipitation changes, except for sea salt deposition in the tropics. Uncertainty in the seasonal, regional cycles of AOD due to assumptions about entrained aerosol wet scavenging is similar in magnitude to the estimated error in the AOD retrievals.

    The uncertainty in aerosol concentrations, burdens, and AOD attributed to different assumptions for the wet scavenging of aerosols entrained above convective cloud bases in a global model motivates the ongoing need to better understand and model the activation and impaction processes that aerosols undergo after entrainment into convective updrafts.

  15. The impact of intermediate wet states on two-phase flow in porous media, studied by network modelling

    Energy Technology Data Exchange (ETDEWEB)

    Hoeiland, Linda Kaada


    Reservoir wettability is a measure of a rocks preference for the oil and/or the brine phase. Wettability has a dominant impact on fluid movements in porous media, hence oil displacement in reservoir rocks. Understanding the local wettability and the effect of wettability on the fluid movements are therefore of interest in relation to oil recovery processes. Contrary to the earlier believed homogenous wetted cases where the porous media was strongly oil-wet for carbonate reservoirs or strongly water-wet for clastic reservoirs, it is now believed that most reservoir rocks experience some kind of intermediate wet state. Since wettability affects oil recovery, different classes of intermediate wettability are expected to have different impacts on the fluid flow processes. The major subject treated in this thesis is how different intermediate wet states affect fluid flow parameters which are important for the oil recovery. This is done by use of a capillary dominated network model of two-phase flow, where the network is based on a model of reconstructed sandstone. The existence of different intermediate wet classes is argued in Paper I, while Paper II, III and IV analyse the effect different intermediate wet classes have on wettability indices, residual oil saturation, capillary pressure and relative permeability (author)

  16. Dynamics of the wet granular Leidenfrost phenomenon. (United States)

    Roeller, Klaus; Herminghaus, Stephan


    By event-driven molecular dynamics simulations, we study the Leidenfrost effect for wet granular matter driven from below. In marked contrast to all earlier studies on other fluids, the dense plug hovering on the hot gas cushion undergoes an undamped oscillation. The location of the Hopf bifurcation leading to this oscillation is strongly dependent on the inelasticity of the grain impacts. The vertical separation into a gas phase with a condensed plug hovering above it is particularly pronounced due to the cohesiveness of the granulate. For sufficiently large system sizes, the Rayleigh-Taylor instability terminates the oscillatory state at late times.

  17. Wetting of two-dimensional physically patterned surfaces (United States)

    Bell, Michael Scott

    An understanding of wetting phenomena is important, in part, due to the many practical applications of controlled wetting. Some of the most exciting applications involve superhydrophobic surfaces, on which water droplets exhibit contact angles larger than 150° and contact angle hysteresis less than 10°. These surfaces are notable for their low-drag, antifouling, and self-cleaning properties, among others. Wetting is known to be affected by both the chemistry and the physical patterning of a surface, with the chemistry affecting what is called the intrinsic contact angle, which is the contact angle displayed by a droplet on a smooth flat surface made of the given material. To date, the largest intrinsic contact angle observed for any material is only about 120°, which does not confer superhydrophobicity. Thus, physical patterning is a crucial component of any superhydrophobic surface. Interestingly, many natural examples of superhydrophobic surfaces exist, with one of the most notable being the lotus leaf. In designing such surfaces, scientists have turned to the natural examples for inspiration, and have found that most natural examples have multiple (usually two) scales of roughness, commonly referred to as hierarchical roughness. Though hierarchical roughness is ubiquitous in the superhydrophobic surfaces of the natural world, its precise role in conferring superhydrophobicity has so far remained elusive. In this work, we develop a thermodynamic model to study the wetting of two-dimensional physically patterned surfaces. Past models that have been developed for this purpose often make several assumptions: the drop must be much larger than the surface features while simultaneously being small enough that the effects of gravity are negligible. Many of these models ultimately rely on the older Cassie and Wenzel models, which themselves make assumptions about the drop size relative to the surface features--namely that the drop is again much larger than the surface

  18. Wet deposition of mercury at Lhasa, the capital city of Tibet. (United States)

    Huang, Jie; Kang, Shichang; Wang, Shuxiao; Wang, Long; Zhang, Qianggong; Guo, Junming; Wang, Kang; Zhang, Guoshuai; Tripathee, Lekhendra


    Quantifying the contribution of mercury (Hg) in wet deposition is important for understanding Hg biogeochemical cycling and anthropogenic sources, and verifying atmospheric models. Mercury in wet deposition was measured over the year 2010, in Lhasa the capital and largest city in Tibet. Precipitation samples were analyzed for total Hg (HgT), particulate-bound Hg (HgP), and reactive Hg (HgR). The volume-weighted mean (VWM) concentrations and wet deposition fluxes of HgT, HgP and HgR in precipitation were 24.8 ng L-1 and 8.2 μg m-2 yr-1, 19.9 ng L-1 and 7.1 μg m-2 yr-1, and 0.5 ng L-1 and 0.19 μg m-2 yr-1, respectively. Concentrations of HgT and HgP were statistically higher during the non-monsoon season than during the monsoon season, while HgR concentrations were statistically higher during the monsoon season than during the non-monsoon season. Most HgT, HgP and HgR wet deposition occurred during the monsoon season. Concentrations of HgP and HgR were 77% and 5% of the HgT on average (VWM), respectively. Concentrations of HgT and HgP were weakly negatively correlated with precipitation amount (r2 = 0.09 and 0.10; p < 0.05), indicating that below-cloud scavenging of Hg from the local atmosphere was an important mechanism contributing Hg to precipitation. High HgP%, as well as a significant positive correlation between HgT and HgP, confirms that Hg wet deposition at Lhasa was primarily occurring in the form of atmospheric HgP below-cloud scavenging. Moreover, the HgT concentration, rather than the precipitation amount, was found to be the governing factor affecting HgT wet deposition flux. A comparison among modeled wet and dry deposition fluxes, and measurements suggested that estimates of both wet and dry Hg deposition fluxes by the GEOS-Chem model were 2 to 3 times higher than the measured annual wet flux. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. A critical analysis of one standard and five methods to monitor surface wetness and time-of-wetness (United States)

    Camuffo, Dario; della Valle, Antonio; Becherini, Francesca


    Surface wetness is a synergistic factor to determine atmospheric corrosion, monument weathering, mould growth, sick buildings, etc. However, its detection and monitoring are neither easy nor homogeneous, for a number of factors that may affect readings. Various types of methods and sensors, either commercial or prototypes built in the lab, have been investigated and compared, i.e. the international standard ISO 9223 to evaluate corrosivity after wetness and time-of-wetness; indirect evaluation of wetness, based on the dew point calculated after the output of temperature and relative humidity sensors and direct measurements by means of capacitive wetness sensors, safety sensors, rain sensors (also known as leaf wetness sensors), infrared reflection sensors and fibre optic sensors. A comparison between the different methods is presented, specifying physical principles, forms of wetting to which they are respondent (i.e. condensation, ice melting, splashing drops, percolation and capillary rise), critical factors, use and cost.

  20. What's So Bad about Being Wet All Over: Investigating Leaf Surface Wetness. (United States)

    Brewer, Carol A.


    Presents investigations of leaf surface wetness that provide ideal opportunities for students to explore the relationships between leaf form and function, to study surface conditions of leaves and plant physiology, and to make predictions about plant adaptation in different environments. Describes simple procedures for exploring questions related…

  1. Understanding Carbohydrates (United States)

    ... Size: A A A Listen En Español Understanding Carbohydrates How much and what type of carbohydrate foods ... glucose levels in your target range. Explore: Understanding Carbohydrates Glycemic Index and Diabetes Learn about the glycemic ...

  2. Reactive wetting by liquid sodium on thin Au platin

    International Nuclear Information System (INIS)

    Kawaguchi, Munemichi; Hamada, Hirotsugu


    For practical use of an under-sodium viewer, the behavior of sodium wetting is investigated by modeling the reactive and non-reactive wetting of metallic-plated steels by liquid sodium to simulate sodium wetting. The non-reactive wetting simulation results showed good agreement with Tanner's law, in which the time dependencies of the droplet radius and contact angle are expressed as R N ∝ t 1/10 and θ∝ t -3/10 , respectively; therefore, the model was considered suitable for the simulation. To simulate reactive wetting, the model of fluid flow induced by the interfacial reaction was incorporated into the simulation of non-reactive wetting. The reactive wetting simulation results, such as the behavior of the precursor liquid film and central droplet, showed good agreement with sodium wetting experiments using thin Au plating at 250°C. An important result of the reactive wetting simulation is that the gradient of the reaction energy at the interface appeared on the new interface around the triple line, and that fluid flow was induced. This interfacial reactivity during sodium wetting of thin Au plating was enhanced by the reaction of sodium and nickel oxide through pinholes in the plating. (author)

  3. Why Wet Kaolin can be used as a Crustal Analog and its Application to Fault Evolution at Restraining Bends (United States)

    Cooke, M. L.; van der Elst, N.; Schottenfeld, M. T.


    To simulate geologic deformation on observable time and length scales within the lab, a subset of analog modelers have used wet kaolin. Unlike the more often used sand, wet kaolin beautifully exhibits detailed fault structures. Furthermore, faults within the kaolin are more readily reactivated than those in sand. The low plasticity of kaolin (compared to other clays) gives it low shear strength. Consequently, the clay is a suitable analog material if we assume that the wet kaolin deforms by coulomb frictional failure. Koalin generally deforms as a Bingham solid and exhibits more complex deformation than the perfectly plastic behavior assumed with Coulomb failure. We performed fall cone and rheometric tests on wet kaolin to refine our quantitative understanding of its rheology. We use North American wet kaolin with density 1.65-1.7 g/cm3 and water content of 37.5-38.5%. The fall cone tests reveal that the undrained shear strength (100-160 Pa) is greater than previously measured with a viscometer. The rheometer tests show that the wet koalin exhibits many of the same properties of crustal materials including: 1) elastic behavior at low strains, 2) stress relaxation at near-failure strains, 3) creep under static load, 4) yield strength sensitive to strain rate and 5) rate and state dependent failure. Armed with quantitative values for this complex deformation, we can better scale the length and strain rate of the wet koalin experiments to specific crustal settings. Experiments of deformation around restraining bends show features very similar to those found in natural examples. The detailed fault structures produced in the wet kaolin can be analyzed to understand the evolution of active faulting at restraining bends.

  4. Doubly Reentrant Cavities Prevent Catastrophic Wetting Transitions on Intrinsically Wetting Surfaces

    KAUST Repository

    Domingues, Eddy


    Omniphobic surfaces, i.e. which repel all known liquids, have proven of value in applications ranging from membrane distillation to underwater drag reduction. A limitation of currently employed omniphobic surfaces is that they rely on perfluorinated coatings, increasing cost and environmental impact, and preventing applications in harsh environments. There is, thus, a keen interest in rendering conventional materials, such as plastics, omniphobic by micro/nano-texturing rather than via chemical make-up, with notable success having been achieved for silica surfaces with doubly reentrant micropillars. However, we found a critical limitation of microtextures comprising of pillars that they undergo catastrophic wetting transitions (apparent contact angles, θr → 0° from θr > 90°) in the presence of localized physical damages/defects or on immersion in wetting liquids. In response, a doubly reentrant cavity microtexture is introduced, which can prevent catastrophic wetting transitions in the presence of localized structural damage/defects or on immersion in wetting liquids. Remarkably, our silica surfaces with doubly reentrant cavities could exhibited apparent contact angles, θr ≈ 135° for mineral oil, where the intrinsic contact angle, θo ≈ 20°. Further, when immersed in mineral oil or water, doubly reentrant microtextures in silica (θo ≈ 40° for water) were not penetrated even after several days of investigation. Thus, microtextures comprising of doubly reentrant cavities might enable applications of conventional materials without chemical modifications, especially in scenarios that are prone to localized damages or immersion in wetting liquids, e.g. hydrodynamic drag reduction and membrane distillation.

  5. Removal of Atmospheric Ethanol by Wet Deposition: A Global Flux Estimate (United States)

    Felix, J. D. D.; Willey, J. D.; Avery, B.; Thomas, R.; Mullaugh, K.; Kieber, R. J.; Mead, R. N.; Helms, J. R.; Campos, L.; Shimizu, M. S.; Guibbina, F.


    Global ethanol fuel consumption has increased exponentially over the last two decades and the US plans to double annual renewable fuel production in the next five years as required by the renewable fuel standard. Regardless of the technology or feedstock used to produce the renewable fuel, the primary end product will be ethanol. Increasing ethanol fuel consumption will have an impact on the oxidizing capacity of the atmosphere and increase atmospheric concentrations of the secondary pollutant peroxyacetyl nitrate as well a variety of VOCs with relatively high ozone reactivities (e.g. ethanol, formaldehyde, acetaldehyde). Despite these documented effects of ethanol emissions on atmospheric chemistry, current global atmospheric ethanol budget models have large uncertainties in the magnitude of ethanol sources and sinks. The presented work investigates the global wet deposition sink by providing the first estimate of the global wet deposition flux of ethanol (2.4 ± 1.6 Tg/yr) based on empirical wet deposition data (219 samples collected at 12 locations). This suggests the wet deposition sink removes between 6 and 17% of atmospheric ethanol annually. Concentrations of ethanol in marine wet deposition (25 ± 6 nM) were an order of magnitude less than in the majority of terrestrial deposition (345 ± 280 nM). Terrestrial deposition collected in locations impacted by high local sources of biofuel usage and locations downwind from ethanol distilleries were an order of magnitude higher in ethanol concentration (3090 ± 448 nM) compared to deposition collected in terrestrial locations not impacted by these sources. These results indicate that wet deposition of ethanol is heavily influenced by local sources and ethanol emission impacts on air quality may be more significant in highly populated areas. As established and developing countries continue to rapidly increase ethanol fuel consumption and subsequent emissions, understanding the magnitude of all ethanol sources and

  6. Tympanoplasty: does dry or wet temporalis fascia graft matter? (United States)

    Singh, G B; Kumar, D; Aggarwal, K; Garg, S; Arora, R; Kumar, S


    To evaluate the success rate of dry and wet temporalis fascia grafts in type I underlay tympanoplasty. A prospective, randomised study was conducted. One hundred adult patients (males and females) with chronic suppurative otitis media (mucosal type) were divided into 2 groups of 50 each: one group underwent dry graft tympanoplasty and the other underwent wet graft tympanoplasty. Fibroblast count was calculated in dry and wet grafts. The dry graft and wet graft groups had overall surgical success rates of 82 and 90 per cent, respectively; this finding was not statistically significant. A statistically significant high fibroblast count was observed in wet grafts, but it did not correlate with surgical success. A dry or wet temporalis fascia graft does not influence the outcome of tympanoplasty type I.

  7. Wet-cupping removes oxidants and decreases oxidative stress. (United States)

    Tagil, Suleyman Murat; Celik, Huseyin Tugrul; Ciftci, Sefa; Kazanci, Fatmanur Hacievliyagil; Arslan, Muzeyyen; Erdamar, Nazan; Kesik, Yunus; Erdamar, Husamettin; Dane, Senol


    Wet-cupping therapy is one of the oldest known medical techniques. Although it is widely used in various conditions such as acute\\chronic inflammation, infectious diseases, and immune system disorders, its mechanism of action is not fully known. In this study, we investigated the oxidative status as the first step to elucidate possible mechanisms of action of wet cupping. Wet cupping therapy is implemented to 31 healthy volunteers. Venous blood samples and Wet cupping blood samples were taken concurrently. Serum nitricoxide, malondialdehyde levels and activity of superoxide dismutase and myeloperoxidase were measured spectrophotometrically. Wet cupping blood had higher activity of myeloperoxidase, lower activity of superoxide dismutase, higher levels of malondialdehyde and nitricoxide compared to the venous blood. Wet cupping removes oxidants and decreases oxidative stress. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Proteomic effects of wet cupping (Al-hijamah). (United States)

    Almaiman, Amer A


    Wet cupping (Al-hijamah) is a therapeutic technique practiced worldwide as a part of the Unani system of medicine. It involves bloodletting from acupoints on a patient's skin to produce a therapeutic outcome. A thorough review of research articles on wet cupping with relevance to proteomics field that are indexed by Google Scholar, PubMed, and/or Science Direct databases was performed. Eight original research articles were summarized in this paper. Overall, wet cupping did not have a significant effect on C-reactive protein, Hsp-27, sister chromatid exchanges, and cell replication index. In contrast, wet cupping was found to produce higher oxygen saturation, eliminate lactate from subcutaneous tissues, remove blood containing higher levels of malondialdehyde and nitric oxide, and produce higher activity of myeloperoxidase. The proteomic effects of wet cupping therapy have not been adequately investigated. Thus, future studies on wet cupping that use systemic and sound protocols to avoid bias should be conducted.

  9. Dynamic wetting with viscous Newtonian and non-Newtonian fluids

    International Nuclear Information System (INIS)

    Wei, Y; Garoff, S; Rame, E; Walker, L M


    We examine various aspects of dynamic wetting with viscous Newtonian and non-Newtonian fluids. Rather than concentrating on the mechanisms that relieve the classic contact line stress singularity, we focus on the behavior in the wedge flow near the contact line which has the dominant influence on wetting with these fluids. Our experiments show that a Newtonian polymer melt composed of highly flexible molecules exhibits dynamic wetting behavior described very well by hydrodynamic models that capture the critical properties of the Newtonian wedge flow near the contact line. We find that shear thinning has a strong impact on dynamic wetting, by reducing the drag of the solid on the fluid near the contact line, while the elasticity of a Boger fluid has a weaker impact on dynamic wetting. Finally, we find that other polymeric fluids, nominally Newtonian in rheometric measurements, exhibit deviations from Newtonian dynamic wetting behavior.


    Directory of Open Access Journals (Sweden)

    Tamara STANCIU


    Full Text Available The heat losses of human body are greater in underwater environment than in dry, normal atmosphere, due to the great heat capacity of water. Body temperature of divers in immersion was studied taking into account the pressure the divers are subjected to. The theoretic equation that describes the total heat transfer- at both levels: skin and respiratory system- was established, considering conduction, convection and respiratory gas heating and humidification. The body temperature of the divers was measured in a series of dives at different depths of immersion, conducted in the wet simulator of the Diving Center, in Constanta. The experimental results were in good accordance with the temperature predicted by the mathematical model.


    Energy Technology Data Exchange (ETDEWEB)

    Youmans-Mcdonald, L.


    Analysis for beryllium by fluorescence is now an established method which is used in many government-run laboratories and commercial facilities. This study investigates the use of this technique using commercially available wet wipes. The fluorescence method is widely documented and has been approved as a standard test method by ASTM International and the National Institute for Occupational Safety and Health (NIOSH). The procedure involves dissolution of samples in aqueous ammonium bifluoride solution and then adding a small aliquot to a basic hydroxybenzoquinoline sulfonate fluorescent dye (Berylliant{trademark} Inc. Detection Solution Part No. CH-2) , and measuring the fluorescence. This method is specific to beryllium. This work explores the use of three different commercial wipes spiked with beryllium, as beryllium acetate or as beryllium oxide and subsequent analysis by optical fluorescence. The effect of possible interfering metals such as Fe, Ti and Pu in the wipe medium is also examined.

  12. Textile UWB Antenna Bending and Wet Performances

    Directory of Open Access Journals (Sweden)

    Mai A. R. Osman


    Full Text Available The vision and ideas of wearable computing systems describe future electronic systems as an integral part of our everyday clothing that provides the wearer with such intelligent personal assistants. Recently, there has been growing interest in the antenna community to merge between wearable systems technology, ultrawideband (UWB technology and textile technology. This work aimed to make closer steps towards real wearability by investigating the possibilities of designing wearable UWB antenna where textile materials are used for the substrate as well as the conducting parts of the designed antenna. Two types of conducting materials have been used for conducting parts, while a nonconducting fabric has been used as antenna substrate material. A set of comparative results of the proposed design were presented and discussed. Moreover, effects on the return loss by means of measurements for each fabricated antenna prototype under bent and fully wet conditions were discussed in more details.

  13. Modelling spontaneous combustion in wet lignite (United States)

    Gong, Rose; Burnell, John G.; Wake, Graeme C.


    A model of self-heating of wet coal is presented. This involves coupled heat and mass transport within a coal pile, together with an exothermic reaction and phase changes of water. There are four state variables: temperature, oxygen, water vapour and liquid water concentrations. Heat and mass are conducted or diffused through the pile, while simultaneously undergoing chemical reaction. As demonstrated by experiment, the heat release rate depends in a quadratic fashion on the liquid water content and this feature is a distinctive aspect of the model. After development of the model, an illustrative spatially uniform model of just three state variables (temperature, oxygen and liquid water concentrations) is analysed for its bifurcational structure of steady states, periodic solutions and their stability. By this means, thresholds for the onset of ignition can be determined as a function of the physical and chemical parameters.

  14. Wetting morphologies on chemically nanopatterned surfaces (United States)

    Checco, Antonio; Gang, Oleg; Ocko, Benjamin M.


    We study the wetting of simple, volatile liquids on model chemical nanopatterns created using Local Oxidation Nanolithography. This technique makes use of a biased, metallic AFM tip to locally oxidize the methyl-terminations of a self-assembled monolayer (octadecylthrichlorosilane) into carboxylic acid termination[1]. With this method we have realized parallel, 50 to 500 nm wide, wettable stripes (carboxylic) embedded into a non-wettable (methyl) surface. Several organic (polar, non-polar), volatile liquids have been condensed onto the wettable stripes and the resulting droplet morphologies have been studied in-situ by using an environmental AFM. We show that close to saturation and for droplet thickness less than 10 nm long-range forces are relevant to the nanoliquid shape. These results are well described by Density Functional Theory assuming dispersive molecular interactions. In addition, we explore the dynamics of condensation/evaporation of the liquid nanodrops.

  15. Wet-Bulb-Globe Temperature Data Report (United States)


    ARL‐SR‐0317 ● MAR 2015          US Army Research Laboratory      Wet‐ Bulb –Globe Temperature Data Report    by David P Sauter...originator.         ARL‐SR‐0317 ● MAR 2015      US Army Research Laboratory      Wet‐ Bulb –Globe Temperature Data Report    by David P Sauter...March 2015 2. REPORT TYPE  Special Report 3. DATES COVERED (From ‐ To)  11 Aug 2014–23 Aug 2014 4. TITLE AND SUBTITLE  Wet- Bulb –Globe Temperature

  16. Flow studies in a wet steam turbine (United States)

    Evans, D. H.; Pouchot, W. D.


    The design and test results of a four stage wet vapor turbine operating with slightly superheated inlet steam and expanding to 10% exit moisture are presented. High speed movies at 3000 frames per second of liquid movement on the pressure side and along the trailing edge of the last stator blade are discussed along with back lighted photographs of moisture drops as they were torn from the stator blade trailing edge. Movies at lower framing rates were also taken of the exit of the last rotating blade and the casing moisture removal slot located in line with the rotor blade shroud. Also moisture removal data are presented of casing slot removal at the exit of the third and fourth rotor blades and for slots located in the trailing edge of the last stator blade. Finally, the degradation of turbine thermodynamic performance due to condensation formation and movement is discussed.

  17. Dynamics of wetting explored with inkjet printing

    Directory of Open Access Journals (Sweden)

    Völkel Simeon


    Full Text Available An inkjet printer head, which is capable of depositing liquid droplets with a resolution of 22 picoliters and high repeatability, is employed to investigate the wetting dynamics of drops printed on a horizontal plane as well as on a granular monolayer. For a sessile drop on a horizontal plane, we characterize the contact angle hysteresis, drop volume and contact line dynamics from side view images. We show that the evaporation rate scales with the dimension of the contact line instead of the surface area of the drop. We demonstrate that the system evolves into a closed cycle upon repeating the depositing-evaporating process, owing to the high repeatability of the printing facility. Finally, we extend the investigation to a granular monolayer in order to explore the interplay between liquid deposition and granular particles.

  18. Timing of wet snow avalanche activity: An analysis from Glacier National Park, Montana, USA. (United States)

    Peitzsch, Erich H.; Hendrikx, Jordy; Fagre, Daniel B.


    Wet snow avalanches pose a problem for annual spring road opening operations along the Going-to-the-Sun Road (GTSR) in Glacier National Park, Montana, USA. A suite of meteorological metrics and snow observations has been used to forecast for wet slab and glide avalanche activity. However, the timing of spring wet slab and glide avalanches is a difficult process to forecast and requires new capabilities. For the 2011 and 2012 spring seasons we tested a previously developed classification tree model which had been trained on data from 2003-2010. For 2011, this model yielded a 91% predictive rate for avalanche days. For 2012, the model failed to capture any of the avalanche days observed. We then investigated these misclassified avalanche days in the 2012 season by comparing them to the misclassified days from the original dataset from which the model was trained. Results showed no significant difference in air temperature variables between this year and the original training data set for these misclassified days. This indicates that 2012 was characterized by avalanche days most similar to those that the model struggled with in the original training data. The original classification tree model showed air temperature to be a significant variable in wet avalanche activity which implies that subsequent movement of meltwater through the snowpack is also important. To further understand the timing of water flow we installed two lysimeters in fall 2011 before snow accumulation. Water flow showed a moderate correlation with air temperature later in the season and no synchronous pattern associated with wet slab and glide avalanche activity. We also characterized snowpack structure as the snowpack transitioned from a dry to a wet snowpack throughout the spring. This helped to assess potential failure layers of wet snow avalanches and the timing of avalanches compared to water moving through the snowpack. These tools (classification tree model and lysimeter data), combined with

  19. New insights on the complex dynamics of two-phase flow in porous media under intermediate-wet conditions. (United States)

    Rabbani, Harris Sajjad; Joekar-Niasar, Vahid; Pak, Tannaz; Shokri, Nima


    Multiphase flow in porous media is important in a number of environmental and industrial applications such as soil remediation, CO 2 sequestration, and enhanced oil recovery. Wetting properties control flow of immiscible fluids in porous media and fluids distribution in the pore space. In contrast to the strong and weak wet conditions, pore-scale physics of immiscible displacement under intermediate-wet conditions is less understood. This study reports the results of a series of two-dimensional high-resolution direct numerical simulations with the aim of understanding the pore-scale dynamics of two-phase immiscible fluid flow under intermediate-wet conditions. Our results show that for intermediate-wet porous media, pore geometry has a strong influence on interface dynamics, leading to co-existence of concave and convex interfaces. Intermediate wettability leads to various interfacial movements which are not identified under imbibition or drainage conditions. These pore-scale events significantly influence macro-scale flow behaviour causing the counter-intuitive decline in recovery of the defending fluid from weak imbibition to intermediate-wet conditions.

  20. Anti wetting additives for aluminosilicate refractories in molten aluminum contact applications (United States)

    Shukla, Devdutt Pramod

    Aluminosilicate based refractories are widely used in furnace installations for melting aluminum because they are inexpensive, readily available and generally exhibit the properties desired from a refractory material. However, they face severe corrosion and degradation issues due to the extremely reducing nature of molten aluminum alloys. Isothermal static cup testing is widely used as a tool to evaluate the performance of refractories against penetration by molten aluminum alloys. Various testing methods were reviewed and an upgraded static cup test was recommended. Commercially available aluminosilicate refractories were tested using this method and their results were studied in order to understand the corrosion process. Barium sulfate, which is widely used as an anti-wetting additive to improve refractory performance by limiting physical contact between molten metal and the refractory, has proved ineffective at temperatures above 1000°C. A literature review suggested that barium sulfate formed barium celsian at high temperatures and that the celsian was responsible for the non-wetting effect. Wetting angle measurements of molten AL 5083 on synthetic celsian discs revealed that barium celsian and strontium celsian were both not wetted by molten aluminum. Static cup tests were performed on aluminosilicate refractories containing barium carbonate and strontium carbonate. These additives led to the in-situ formation of celsian phases within the refractory matrix that led to improved corrosion resistance at 1300°C. Phase analysis revealed that celsian formation suppressed the formation of mullite within refractories, thereby reducing penetration.

  1. Impact of Asphaltenes and Resins on the Wetting Characteristics of Tars at Former Manufactured Gas Plants (United States)

    Hauswirth, S. C.; Birak, P. S.; Rylander, S.; Pedit, J. A.; Miller, C. T.


    Tars produced as a byproduct of coal and oil gasification at manufactured gas plants (MGPs) during the 19th and early 20th centuries were often released into the environment through poor disposal practices or leaks in holding tanks and piping. These tars are persistent contaminants, leaching polycyclic aromatic hydrocarbons (PAHs) into groundwater and posing a significant risk to human and ecological health. MGP tars also have several properties that make them notoriously difficult to remediate. They are denser than water, so they can migrate to depths which make direct removal difficult or impossible, and their relatively high viscosities and ability to alter the wetting characteristics of porous media result in inefficient removal by traditional pump-and-treat methods. In this study, we investigate the last of these properties. Previous studies have linked wetting changes to asphaltenes---polar, high molecular weight compounds present in the tars. However, we have conducted qualitative bottle tests for tar samples collected from two former MGPs which indicate that there is no direct correlation between asphaltene concentration and the tendency to alter wetting characteristics of porous media. To better understand the factors controlling wetting behavior, we isolate asphaltenes and resins, another class of polar compounds, from a tar sample and recombine them with the remaining PAH mixture to create a series of tars of varying composition. We assess the relative impact of each of the fractions on wettability through contact angle measurements conducted at three different pHs.

  2. Moving contact lines in partial wetting: bridging the gap across the scales (United States)

    Pahlavan, Amir; Cueto-Felgueroso, Luis; McKinley, Gareth; Juanes, Ruben


    The spreading and dewetting of liquid films on solid substrates is a common phenomenon in nature and industry from a snail secreting a mucosal film to printing and coating processes. A quantitative description of these phenomena, however, requires a detailed understanding of the flow physics at the nanoscale as the intermolecular interactions become important close to the contact line. Classical hydrodynamic theory describes wetting as an interplay between viscous and interfacial forces, neglecting the intermolecular interactions, leading to a paradox known as the moving contact line singularity. By contrast, molecular kinetic theory describes wetting as an activated process, neglecting the bulk hydrodynamics in the spreading viscous fluid film altogether. Here, we show that our recently developed model for thin liquid films in partial wetting, which properly incorporates the role of van der Waals interactions in a thin spreading fluid layer into a height-dependent surface tension, bridges the gap between these two approaches and leads to a unified framework for the description of wetting phenomena. We further use our model to investigate the instability and dewetting of nanometric liquid films, and show that it brings theoretical predictions closer to experimental observations.

  3. Understanding classification

    NARCIS (Netherlands)

    Subianto, M.


    In practical data analysis, the understandability of models plays an important role in their acceptance. In the data mining literature, however, understandability plays is hardly ever mentioned. If it is mentioned, it is interpreted as meaning that the models have to be simple. In this thesis we

  4. Embodied understanding. (United States)

    Johnson, Mark


    Western culture has inherited a view of understanding as an intellectual cognitive operation of grasping of concepts and their relations. However, cognitive science research has shown that this received intellectualist conception is substantially out of touch with how humans actually make and experience meaning. The view emerging from the mind sciences recognizes that understanding is profoundly embodied, insofar as our conceptualization and reasoning recruit sensory, motor, and affective patterns and processes to structure our understanding of, and engagement with, our world. A psychologically realistic account of understanding must begin with the patterns of ongoing interaction between an organism and its physical and cultural environments and must include both our emotional responses to changes in our body and environment, and also the actions by which we continuously transform our experience. Consequently, embodied understanding is not merely a conceptual/propositional activity of thought, but rather constitutes our most basic way of being in, and engaging with, our surroundings in a deep visceral manner.

  5. Should there be a "Wet" Soil Order in Soil Taxonomy? (United States)

    Rabenhorst, Martin; Wessel, Barret; Stolt, Mark; Lindbo, David


    Early soil classification systems recognized wet soils at the highest categorical level. Among the Intrazonal Soils of the US classification utilized between the 1920s and 1960, were included as Great Soil Groups, the Wiesenboden, Bog, Half-Bog, Ground-Water Podzols and Ground-Water Laterites. In other systems, groups named with such terms as ground water gley and pseudogley were also used. With the advent of Soil Taxonomy and it's precursor (1960, 1975), Histosols (organic soils) were distinguished as one of the initial 10 soil orders, and while many of these organic soils are wet soils, some are not (Folists for example). Thus, for over 50 years, with the exception of Histosols, wet soils (which typically represent the wettest end of subaerial wet soils) have not been collectively recognized within taxa at the highest categorical level (order) in the US soil classification system. Rather, the wettest soils were designated at the second categorical level as wet (Aqu) suborders among the various soil orders, and more recently, subaqueous soils as "Wass" suborders of Entisols and Histosols. Soils with less-wet conditions have been recognized at the subgroup (4th) level. Further, in impoundments and regions of transgressing coastlines, submerged upland soils have been found that still classify in soil orders that do not accommodate subaqueous soils ("Wass" suborders). Notwithstanding, other contemporary soil classification systems do (have continued to) recognize wet soils at the highest level. In the World Reference Base (WRB) for example, wet soils are designated as Gleysols or Stagnosols. As efforts are underway to revisit, simplify, and revise Soil Taxonomy, questions have been raised regarding whether wet soils should again be moved back with a place among taxa at the highest category using a name such as Hydrasols, Aquasols, etc. This paper will explore and consider the questions and arguments for and against such proposals and the difficult question regarding

  6. GPD+ wet tropospheric correctionsfor eight altimetric missions (United States)

    Fernandes, Joana; Benveniste, Jérôme; Lázaro, Clara


    Due to its large space-temporal variability, the delay induced by the water vapour and liquid water content of the atmosphere in the altimeter signal or wet tropospheric delay (WTD) is still one of the largest sources of uncertainty in satellite altimetry. In the scope of the Sea Level Climate Change Initiative (SL-cci) project, the University of Porto (UPorto) has been developing methods to improve the wet tropospheric correction (WTC), which corrects for the effect of the WPD in the altimetric measurements. Developed as a coastal algorithm to remove land effects in the microwave radiometers (MWR) on board altimeter missions, the GNSS-derived Path Delay (GPD) methodology evolved over time, currently correcting for invalid observations due to land, ice and rain contamination, band instrument malfunction in open ocean, coastal and polar regions. The most recent version of the algorithm, GPD Plus (GPD+) computes wet path delays based on: i) WTC from the on-board MWR measurements, whenever they exist and are valid; ii) new WTC values estimated through space-time objective analysis of all available data sources, whenever the previous are considered invalid. In the estimation of the new WTC values, the following data sets are used: valid measurements from the on-board MWR, water vapour products derived from a set of 17 scanning imaging radiometers (SI-MWR) on board various remote sensing satellites and tropospheric delays derived from Global Navigation Satellite Systems (GNSS) coastal and island stations. In the estimation process, WTC derived from an atmospheric model such as the European Centre for Medium-range Weather Forecasts (ECMWF) ReAnalysis (ERA) Interim or the operational (Op) model are used as first guess, which is the adopted value in the absence of measurements. The corrections are provided for the most recent products of all missions used to generate the SL Essential Climate Variable (ECV): TOPEX/Poseidon- T/P, Jason-1, Jason-2, ERS-1, ERS-2, CryoSat-2

  7. Characterizing wet slab and glide slab avalanche occurrence along the Going-to-the-Sun Road, Glacier National Park, Montana, USA (United States)

    Peitzsch, Erich H.; Hendrikx, Jordy; Fagre, Daniel B.; Reardon, Blase


    Wet slab and glide slab snow avalanches are dangerous and yet can be particularly difficult to predict. Both wet slab and glide slab avalanches are thought to depend upon free water moving through the snowpack but are driven by different processes. In Glacier National Park, Montana, both types of avalanches can occur in the same year and affect the Going-to-the-Sun Road (GTSR). Both wet slab and glide slab avalanches along the GTSR from 2003-2010 are investigated. Meteorological data from two high-elevation weather stations and one SNOTEL site are used in conjunction with an avalanche database and snowpit profiles. These data were used to characterize years when only glide slab avalanches occurred and those years when both glide slab and wet slab avalanches occurred. Results of 168 glide slab and 57 wet slab avalanches along the GTSR suggest both types of avalanche occurrence depend on sustained warming periods with intense solar radiation (or rain on snow) to produce free water in the snowpack. Differences in temperature and net radiation metrics between wet slab and glide slab avalanches emerge as one moves from one day to seven days prior to avalanche occurrence. On average, a more rapid warming precedes wet slab avalanche occurrence. Glide slab and wet slab avalanches require a similar amount of net radiation. Wet slab avalanches do not occur every year, while glide slab avalanches occur annually. These results aim to enhance understanding of the required meteorological conditions for wet slab and glide slab avalanches and aid in improved wet snow avalanche forecasting.

  8. Analysis on Wetting Deformation Properties of Silty Clay

    Directory of Open Access Journals (Sweden)

    Xinrong Liu


    Full Text Available Changes in water level that cause deformation and stability problems often occur in foundation pit engineering. Water damage is one of the main problems that will lead to disasters in foundation pit engineering. Research findings with regard to properties of wetting deformation due to water damage can be applied not only in foundation pit engineering, slope engineering, hydraulic engineering, and mining engineering but also in related issues in the field of theoretical research and practice. In this study, the characteristics of silty clay deformation after wetting are examined from the perspective of the effect of wetting on the side wall of foundation pit, and wetting experiments on silty clay of a selected area’s stratum located in Chongqing Municipality are conducted under different confining pressures and stress levels through a multi-function triaxial apparatus. Then, laws of silty clay wetting deformation are obtained, and the relationship between wetting stress level and wetting deformation amount is also figured out. The study reveals that the maximum values of wetting deformation under different confining pressures have appear at a particular stress level; therefore, the related measures should be taken to avoid this deformation in the process of construction.

  9. Electrophoretic deposition of titania nanoparticles: Wet density of ...

    Indian Academy of Sciences (India)

    ... with time and attained the plateau at longer times. The velocity at which particles attach to the deposit, strongly influences its wet density at initial times. However, the effect of electro-osmotic flow is dominant at longer times. The coating with higher wet density had the higher corrosion resistance in Ringer's solution at 37.5 ...

  10. Exposure of the hands to wet work in nurses

    NARCIS (Netherlands)

    Jungbauer, F.H.W.; Lensen, G.J.; Groothoff, J.W.; Coenraads, P.J.

    Prevention of hand dermatitis among nurses can be achieved by reduction of wet-work exposure. A preventive programme should be based on knowledge of exposure levels. An accurate method to assess such exposure levels is needed. Duration and frequency of wet-work activities were assessed by a

  11. The Influence of Wetting Rate and Electrolyte Concentration on the ...

    African Journals Online (AJOL)

    The hydrologic response of a degraded red earth's topsoil to varying wetting rates (w) followed by falling electrolyte concentration (c) was investigated. Rapid wetting and the resulting structural failure increased total porosity and water retention across the 0 to 1500 kPa matric potential range. Substantial macroscopic ...

  12. Phase change materials and the perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kosters, N.D.; Kappers, A.M.L.; Daanen, H.A.M.


    Phase change materials (PCMs) are increasingly incorporated in textiles in order to serve as a thermal buffer when humans change from a hot to a cold environment and the reverse. Due to the absence of wetness sensors in the skin, cooling of the skin may be perceived as a sensation of wetness instead

  13. Electrophoretic deposition of titania nanoparticles: Wet density of ...

    Indian Academy of Sciences (India)


    Abstract. Electrophoretic deposition (EPD) of titania nanoparticles was performed at different voltages and times. The wet density of deposits was calculated according to the Archimedes' principle. The wet density as well as the electric field over the deposits increased with time and attained the plateau at longer times. The.

  14. Wet season spatial occurrence of phytoplankton and zooplankton in ...

    African Journals Online (AJOL)

    Science World Journal ... Investigation into the spatial occurrence of wet season phytoplankton and zooplankton in Lagos lagoon, Nigeria was carried out in October, 2008 in 12 stations. A total of ... The wet season spectrum of the lagoon was dominated by diatoms for the phytoplankton and copepods for the zooplankton.

  15. Fingerlike wetting patterns in two water-repellent loam soils

    NARCIS (Netherlands)

    Dekker, L.W.; Ritsema, C.J.


    In soils with fingered flow, surface-applied solutes can reach the groundwater more rapidly than in the case of homogeneous wetting. This study was undertaken to demonstrate the occurrence of finger-like wetting patterns in a silt loam soil and a silty clay loam soil, and to investigate the

  16. Phase Change Materials and the perception of wetness.

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kappers, A.M.L.; Daanen, H.A.M.


    Phase change materials (PCMs) are increasingly incorporated in textiles in order to serve as a thermal buffer when humans change from a hot to a cold environment and the reverse. Due to the absence of wetness sensors in the skin, cooling of the skin may be perceived as a sensation of wetness instead

  17. Electrophoretic deposition of titania nanoparticles: Wet density of ...

    Indian Academy of Sciences (India)


    Electrophoretic deposition (EPD); electro-osmotic flow; titania nanoparticles; triethanolamine. (TEA); wet density. 1. .... (25 °C) and atmospheric pressure. The immersion weight ... Wet density of deposits and velocity of electro-osmotic flow against TEA concentration at (a) 60 and (b) 200 V and longer EPD times (360 s).

  18. Southern African Regional Science Initiative (SAFARI 2000): wet season campaigns

    CSIR Research Space (South Africa)

    Otter, LB


    Full Text Available The Southern African Regional Science Initiative (SAFARI 2000) involved two wet season and one dry season field campaigns. This paper reports on the wet season campaigns. The first was conducted at five sites along the Kalahari Transect in Zambia...

  19. Spatial and temporal variations in the occurrences of wet periods ...

    Indian Academy of Sciences (India)

    This study highlights the hydro-climatic features of the five wet periods contributing in different percentages to the annual rainfall total over major river basins in India.Spatial and temporal variations in the parameters such as starting date,duration and rainfall intensity of these wet periods throughout India have been ...

  20. Comparative Batch and Column Evaluation of Thermal and Wet ...

    African Journals Online (AJOL)

    batch adsorption experiments and continous flow (fixed bed) column experiment to study the mechanism of dye removal by the commercial ... compared with those obtained for thermal regeneration method (qmax = 61.73mgg-1) and wet oxidative method (qmax .... Carbon hardness was determined using a wet attrition test ...

  1. Tactile cues significantly modulate the perception of sweat-induced skin wetness independently of the level of physical skin wetness. (United States)

    Filingeri, Davide; Fournet, Damien; Hodder, Simon; Havenith, George


    Humans sense the wetness of a wet surface through the somatosensory integration of thermal and tactile inputs generated by the interaction between skin and moisture. However, little is known on how wetness is sensed when moisture is produced via sweating. We tested the hypothesis that, in the absence of skin cooling, intermittent tactile cues, as coded by low-threshold skin mechanoreceptors, modulate the perception of sweat-induced skin wetness, independently of the level of physical wetness. Ten males (22 yr old) performed an incremental exercise protocol during two trials designed to induce the same physical skin wetness but to induce lower (TIGHT-FIT) and higher (LOOSE-FIT) wetness perception. In the TIGHT-FIT, a tight-fitting clothing ensemble limited intermittent skin-sweat-clothing tactile interactions. In the LOOSE-FIT, a loose-fitting ensemble allowed free skin-sweat-clothing interactions. Heart rate, core and skin temperature, galvanic skin conductance (GSC), and physical (w(body)) and perceived skin wetness were recorded. Exercise-induced sweat production and physical wetness increased significantly [GSC: 3.1 μS, SD 0.3 to 18.8 μS, SD 1.3, P 0.05). However, the limited intermittent tactile inputs generated by the TIGHT-FIT ensemble reduced significantly whole-body and regional wetness perception (P < 0.01). This reduction was more pronounced when between 40 and 80% of the body was covered in sweat. We conclude that the central integration of intermittent mechanical interactions between skin, sweat, and clothing, as coded by low-threshold skin mechanoreceptors, significantly contributes to the ability to sense sweat-induced skin wetness. Copyright © 2015 the American Physiological Society.

  2. Understanding semantics

    DEFF Research Database (Denmark)

    Thrane, Torben


    Understanding natural language is a cognitive, information-driven process. Discussing some of the consequences of this fact, the paper offers a novel look at the semantic effect of lexical nouns and the identification of reference types....

  3. Understanding Alzheimer's (United States)

    ... Navigation Bar Home Current Issue Past Issues Understanding Alzheimer's Past Issues / Fall 2007 Table of Contents For ... and brain scans. No treatment so far stops Alzheimer's. However, for some in the disease's early and ...

  4. Modeling and optimization of wet sizing process

    International Nuclear Information System (INIS)

    Thai Ba Cau; Vu Thanh Quang and Nguyen Ba Tien


    Mathematical simulation on basis of Stock law has been done for wet sizing process on cylinder equipment of laboratory and semi-industrial scale. The model consists of mathematical equations describing relations between variables, such as: - Resident time distribution function of emulsion particles in the separating zone of the equipment depending on flow-rate, height, diameter and structure of the equipment. - Size-distribution function in the fine and coarse parts depending on resident time distribution function of emulsion particles, characteristics of the material being processed, such as specific density, shapes, and characteristics of the environment of classification, such as specific density, viscosity. - Experimental model was developed on data collected from an experimental cylindrical equipment with diameter x height of sedimentation chamber equal to 50 x 40 cm for an emulsion of zirconium silicate in water. - Using this experimental model allows to determine optimal flow-rate in order to obtain product with desired grain size in term of average size or size distribution function. (author)

  5. Thin wetting film lens-less imaging

    International Nuclear Information System (INIS)

    Allier, C.P.; Poher, V.; Coutard, J.G.; Hiernard, G.; Dinten, J.M.


    Lens-less imaging has recently attracted a lot of attention as a compact, easy-to-use method to image or detect biological objects like cells, but failed at detecting micron size objects like bacteria that often do not scatter enough light. In order to detect single bacterium, we have developed a method based on a thin wetting film that produces a micro-lens effect. Compared with previously reported results, a large improvement in signal to noise ratio is obtained due to the presence of a micro-lens on top of each bacterium. In these conditions, standard CMOS sensors are able to detect single bacterium, e.g. E. coli, Bacillus subtilis and Bacillus thuringiensis, with a large signal to noise ratio. This paper presents our sensor optimization to enhance the SNR; improve the detection of sub-micron objects; and increase the imaging FOV, from 4.3 mm 2 to 12 mm 2 to 24 mm 2 , which allows the detection of bacteria contained in 0.5 μl to 4 μl to 10 μl, respectively. (authors)

  6. Photochemical organonitrate formation in wet aerosols (United States)

    Lim, Yong Bin; Kim, Hwajin; Kim, Jin Young; Turpin, Barbara J.


    Water is the most abundant component of atmospheric fine aerosol. However, despite rapid progress, multiphase chemistry involving wet aerosols is still poorly understood. In this work, we report results from smog chamber photooxidation of glyoxal- and OH-containing ammonium sulfate or sulfuric acid particles in the presence of NOx and O3 at high and low relative humidity. Particles were analyzed using ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). During the 3 h irradiation, OH oxidation products of glyoxal that are also produced in dilute aqueous solutions (e.g., oxalic acids and tartaric acids) were formed in both ammonium sulfate (AS) aerosols and sulfuric acid (SA) aerosols. However, the major products were organonitrogens (CHNO), organosulfates (CHOS), and organonitrogen sulfates (CHNOS). These were also the dominant products formed in the dark chamber, indicating non-radical formation. In the humid chamber (> 70 % relative humidity, RH), two main products for both AS and SA aerosols were organonitrates, which appeared at m / z- 147 and 226. They were formed in the aqueous phase via non-radical reactions of glyoxal and nitric acid, and their formation was enhanced by photochemistry because of the photochemical formation of nitric acid via reactions of peroxy radicals, NOx and OH during the irradiation.

  7. Wetting hysteresis of nanodrops on nanorough surfaces (United States)

    Chang, Cheng-Chung; Sheng, Yu-Jane; Tsao, Heng-Kwong


    Nanodrops on smooth or patterned rough surfaces are explored by many-body dissipative particle dynamics to demonstrate the influence of surface roughness on droplet wetting. On a smooth surface, nanodrops exhibit the random motion and contact angle hysteresis is absent. The diffusivity decays as the intrinsic contact angle (θY) decreases. On a rough surface, the contact line is pinned and the most stable contact angle (θY') is acquired. The extent of contact angle hysteresis (Δ θ ) is determined by two approaches, which resemble the inflation-deflation method and inclined plane method for experiments. The hysteresis loop is acquired and both approaches yield consistent results. The influences of wettability and surface roughness on θY' and Δ θ are examined. θY' deviates from that estimated by the Wenzel or Cassie-Baxter models. This consequence can be explained by the extent of impregnation, which varies with the groove position and wettability. Moreover, contact angle hysteresis depends more on the groove width than the depth.

  8. Green Gasification Technology for Wet Biomass

    Directory of Open Access Journals (Sweden)

    W. H. Chong


    Full Text Available The world now is facing two energy related threats which are lack of sustainable, secure and affordable energy supplies and the environmental damage acquired in producing and consuming ever-increasing amount of energy. In the first decade of the twenty-first century, increasing energy prices reminds us that an affordable energy plays an important role in economic growth and human development. To overcome the abovementioned problem, we cannot continue much longer to consume finite reserves of fossil fuels, the use of which contributes to global warming. Preferably, the world should move towards more sustainable energy sources such as wind energy, solar energy and biomass. However, the abovementioned challenges may not be met solely by introduction of sustainable energy forms. We also need to use energy more efficiently. Developing and introducing more efficient energy conversion technologies is therefore important, for fossil fuels as well as renewable fuels. This assignment addresses the question how biomass may be used more efficiently and economically than it is being used today. Wider use of biomass, a clean and renewable feedstock may extend the lifetime of our fossil fuels resources and alleviate global warming problems. Another advantage of using of biomass as a source of energy is to make developed countries less interdependent on oil-exporting countries, and thereby reduce political tension. Furthermore, the economies of agricultural regions growing energy crops benefit as new jobs are created. Keywords: energy, gasification, sustainable, wet biomass

  9. Wet Beriberi Associated with Hikikomori Syndrome. (United States)

    Tanabe, Natsumi; Hiraoka, Eiji; Kataoka, Jun; Naito, Takaki; Matsumoto, Ko; Arai, Junya; Norisue, Yasuhiro


    Wet beriberi, characterized by high cardiac output with predominantly right-sided heart failure and lactic acidosis, is a disease caused by thiamine deficiency, and is rarely seen in modern society. However, patients with social withdrawal syndrome, also known as hikikomori syndrome, may be a new population at risk of thiamine deficiency. Hikikomori syndrome, first recognized in Japan, is becoming a worldwide issue. A 39-year-old Japanese patient was brought to our hospital, with a 3-week history of progressive shortness of breath and generalized edema. The patient had right-sided high-output heart failure, lactic acidosis, and Wernicke-Korsakoff syndrome. Because of his history of social isolation, we diagnosed hikikomori syndrome according to the Japanese government's definition, which is as follows: lifestyle centered at home; no interest or willingness to attend school or work; persistence of symptoms beyond 6 months; and exclusion of other psychiatric and developmental disorders. Considering his diagnosis of hikikomori syndrome and social isolation, we suspected malnutrition, particularly thiamine deficiency, and successfully treated him. Clinicians should be aware of the potential risk of thiamine deficiency associated with hikikomori syndrome and initiate thiamine replacement in cases of high-output heart failure associated with lactic acidosis.

  10. Aerial shaking performance of wet Anna's hummingbirds (United States)

    Ortega-Jimenez, Victor Manuel; Dudley, Robert


    External wetting poses problems of immediate heat loss and long-term pathogen growth for vertebrates. Beyond these risks, the locomotor ability of smaller animals, and particularly of fliers, may be impaired by water adhering to the body. Here, we report on the remarkable ability of hummingbirds to perform rapid shakes in order to expel water from their plumage even while in flight. Kinematic performance of aerial versus non-aerial shakes (i.e. those performed while perching) was compared. Oscillation frequencies of the head, body and tail were lower in aerial shakes. Tangential speeds and accelerations of the trunk and tail were roughly similar in aerial and non-aerial shakes, but values for head motions in air were twice as high when compared with shakes while perching. Azimuthal angular amplitudes for both aerial and non-aerial shakes reached values greater than 180° for the head, greater than 45° for the body trunk and slightly greater than 90° for the tail and wings. Using a feather on an oscillating disc to mimic shaking motions, we found that bending increased average speeds by up to 36 per cent and accelerations of the feather tip up to fourfold relative to a hypothetical rigid feather. Feather flexibility may help to enhance shedding of water and reduce body oscillations during shaking. PMID:22072447

  11. Wetting of silicone oil onto a cell-seeded substrate (United States)

    Lu, Yongjie; Chan, Yau Kei; Chao, Youchuang; Shum, Ho Cheung


    Wetting behavior of solid substrates in three-phase systems containing two immiscible liquids are widely studied. There exist many three-phase systems in biological environments, such as droplet-based microfluidics or tamponade of silicone oil for eye surgery. However, few studies focus on wetting behavior of biological surfaces with cells. Here we investigate wetting of silicone oil onto cell-seeded PMMA sheet immersed in water. Using a simple parallel-plate cell, we show the effect of cell density, viscosity of silicone oil, morphology of silicone oil drops and interfacial tension on the wetting phenomenon. The dynamics of wetting is also observed by squeezing silicone oil drop using two parallel plates. Experimental results are explained based on disjoining pressure which is dependent on the interaction of biological surfaces and liquid used. These findings are useful for explaining emulsification of silicone oil in ophthalmological applications.

  12. Modeling the wet bulb globe temperature using standard meteorological measurements. (United States)

    Liljegren, James C; Carhart, Richard A; Lawday, Philip; Tschopp, Stephen; Sharp, Robert


    The U.S. Army has a need for continuous, accurate estimates of the wet bulb globe temperature to protect soldiers and civilian workers from heat-related injuries, including those involved in the storage and destruction of aging chemical munitions at depots across the United States. At these depots, workers must don protective clothing that increases their risk of heat-related injury. Because of the difficulty in making continuous, accurate measurements of wet bulb globe temperature outdoors, the authors have developed a model of the wet bulb globe temperature that relies only on standard meteorological data available at each storage depot for input. The model is composed of separate submodels of the natural wet bulb and globe temperatures that are based on fundamental principles of heat and mass transfer, has no site-dependent parameters, and achieves an accuracy of better than 1 degree C based on comparisons with wet bulb globe temperature measurements at all depots.

  13. Understanding homelessness


    Somerville, Peter


    This paper reviews the literature on understanding homelessness. It criticizes approaches that ignore, distort or diminish the humanity of homeless people, or else, add little to our understanding of that humanity. In particular, it rejects what it calls “epidemiological” approaches, which deny the possibility of agency for homeless people, insofar as those approaches view the situation of those people largely as a “social fact”, to be explained in terms of causal variables or “risk factors” ...

  14. The sensitivity of Sphagnum to surface layer conditions in a re-wetted bog: a simulation study of water stress

    NARCIS (Netherlands)

    Schouwenaars, J.M.; Gosen, A.M.


    The behaviour of the water table in re-wetted bogs varies widely between different locations so that recolonising Sphagnum is vulnerable to water stress, especially when the water table is drawn down in summer. It is important to understand how physical site conditions influence the occurrence of

  15. Increases in mean annual temperature do not alter soil bacterial community structure in tropical montane wet forests (United States)

    Paul C. Selmants; Karen L. Adair; Creighton M. Litton; Christian P. Giardina; Egbert Schwartz


    Soil bacteria play a key role in regulating terrestrial biogeochemical cycling and greenhouse gas fluxes across the soil-atmosphere continuum. Despite their importance to ecosystem functioning, we lack a general understanding of how bacterial communities respond to climate change, especially in relatively understudied ecosystems like tropical montane wet...

  16. The Dependency between the Arabian Peninsula Wet Events and Sea Level Pressure Patterns during Spring Season

    KAUST Repository

    El Kenawy, Ahmed M.


    This work investigates the relationships between regional extreme wet events in the Arabian Peninsula during the spring season (MAM) and sea level pressure (SLP) patterns. Based on NCEP/NCAR reanalysis data, S-mode principal components were computed from the de-seasonalized daily SLP for spring months between 1960 and 2013. The analysis covered a window for the region (15-70°E and 2.5-50°N). This window coupled different oceanic-land influences (e.g. the Indian, Mediterranean and the Sahara configurations) that may impart an effect on rainfall variations in the study domain. A set of eight significant circulation spatial patterns were retained, which explained 84.8% of the total explained variance. The derived patterns explained a wide variety of flows over the peninsula, with a clear distinction between zonal and meridional advections. The extreme wet events (R95 and R99) were defined from a relatively dense network of 209 observatories covering the peninsula, using the 95th and 99th percentile of rainfall distribution respectively. The links between the dominant SLP patterns and significant wet events were established and the physical interpretations of these associations were examined. The results, as revealed by the location and intensity of high pressure centers, highlight the strength of eastern and southeastern advections corresponding to these extreme events. Other patterns have a local character, suggesting an orographic origin of some wet events in the region. The relationships described in this research can advance the understanding of the large-scale processes that contribute to the wet weather events in the Arabian Peninsula. These findings can therefore contribute to better management of water resources and agricultural practices in the region.

  17. Quantification of wet-work exposure in nurses using a newly developed wet-work exposure monitor

    NARCIS (Netherlands)

    Visser, Maaike J.; Behroozy, Ali; Verberk, Maarten M.; Semple, Sean; Kezic, Sanja


    Occupational contact dermatitis (OCD) is an important work-related disease. A major cause of OCD is 'wet work': frequent contact of the skin with water, soap, detergents, or occlusive gloves. The German guidance TRGS 401 recommends that the duration of wet work (including use of occlusive gloves)

  18. Wetting and surface tension of bismate glass melt

    International Nuclear Information System (INIS)

    Shim, Seung-Bo; Kim, Dong-Sun; Hwang, Seongjin; Kim, Hyungsun


    Lead oxide glass frits are used widely in the electronics industry for low-temperature firing. On the other hand, one of the low-sintering and low-melting lead-free glass systems available, the bismate glass system, is considered to be an alternative to lead oxide glass. In order to extend the applications of Bi 2 O 3 glasses, this study examined the thermophysical properties of low-melting Bi 2 O 3 -B 2 O 3 -ZnO-BaO-Al 2 O 3 -SiO 2 glass frits with various ZnO/B 2 O 3 ratios. The fundamental thermal properties, such as glass transition temperature and softening point, were examined by differential thermal analysis and a glass softening point determination system. The wetting angles, viscosities and surface tension of the various bismate glasses on an alumina substrate were measured using hot-stage microscopy and the sessile drop method. These thermophysical properties will be helpful in understanding the work of adhesion and the liquid spread kinetics of glass frits.

  19. Coffee-stain growth dynamics on dry and wet surfaces (United States)

    Boulogne, François; Ingremeau, François; Stone, Howard A.


    The drying of a drop containing particles often results in the accumulation of the particles at the contact line. In this work, we investigate the drying of an aqueous colloidal drop surrounded by a hydrogel that is also evaporating. We combine theoretical and experimental studies to understand how the surrounding vapor concentration affects the particle deposit during the constant radius evaporation mode. In addition to the common case of evaporation on an otherwise dry surface, we show that in a configuration where liquid is evaporating from a flat surface around the drop, the singularity of the evaporative flux at the contact line is suppressed and the drop evaporation is homogeneous. For both conditions, we derive the velocity field and we establish the temporal evolution of the number of particles accumulated at the contact line. We predict the growth dynamics of the stain and the drying timescales. Thus, dry and wet conditions are compared with experimental results and we highlight that only the dynamics is modified by the evaporation conditions, not the final accumulation at the contact line.

  20. Gecko Adhesion on Wet and Dry Patterned Substrates.

    Directory of Open Access Journals (Sweden)

    Alyssa Y Stark

    Full Text Available Perhaps one of the most astounding characteristics of the gecko adhesive system is its versatility. Geckos can locomote across complex substrates in a variety of conditions with apparent ease. In contrast, many of our synthetic pressure sensitive adhesives fail on substrates that are dirty, wet or rough. Although many studies have investigated the effect of environmental challenges on performance, the interaction of multiple, potentially compromising variables is studied less often. Here we focus on substrate structure and surface water, both of which are highly relevant to the biological system and to synthetic design. To do this we utilized a highly controlled, patterned substrate (Sharklet®, by Sharklet® Technologies Inc.. This allowed us to test independently and jointly the effects of reduced surface area substrates, with a defined pattern, on adhesion in both air and water. Our results show that adhesion is not significantly impaired in air, whereas surface area and pattern significantly affect adhesion in water. These findings highlight the need to study multiple parameters that are relevant to the gecko adhesive system to further improve our understanding of the biological system and to design better, more versatile synthetics.

  1. Freeze-drying wet digital prints: An option for salvage?

    International Nuclear Information System (INIS)

    Juergens, M C; Schempp, N


    On the occasion of the collapse of the Historical Archive of the City of Cologne in March 2009 and the ensuing salvage effort, questions were raised about the use of freeze-drying for soaked digital prints, a technique that has not yet been evaluated for these materials. This study examines the effects of immersion, air-drying, drying in a blotter stack, freezing and freeze-drying on 35 samples of major digital printing processes. The samples were examined visually before, during and after testing; evaluation of the results was qualitative. Results show that some prints were already damaged by immersion alone (e.g. bleeding inks and soluble coatings) to the extent that the subsequent choice of drying method made no significant difference any more. For those samples that did survive immersion, air-drying proved to be crucial for water-sensitive prints, since any contact with the wet surface caused serious damage. Less water-sensitive prints showed no damage throughout the entire procedure, regardless of drying method. Some prints on coated media suffered from minor surface disruption up to total delamination of the surface coating due to the formation of ice crystals during shock-freezing. With few exceptions, freeze-drying did not cause additional damage to any of the prints that hadn't already been damaged by freezing. It became clear that an understanding of the process and materials is important for choosing an appropriate drying method.

  2. Precipitation chemistry and wet deposition in a remote wet savanna site in West Africa: Djougou (Benin) (United States)

    Akpo, A. B.; Galy-Lacaux, C.; Laouali, D.; Delon, C.; Liousse, C.; Adon, M.; Gardrat, E.; Mariscal, A.; Darakpa, C.


    In the framework of the IDAF (IGAC/DEBITS/AFrica) international program, this study aims to study the chemical composition of precipitation and associated wet deposition at the rural site of Djougou in Benin, representative of a West and Central African wet savanna. Five hundred and thirty rainfall samples were collected at Djougou, Benin, from July 2005 to December 2009 to provide a unique database. The chemical composition of precipitation was analyzed for inorganic (Ca2+, Mg2+, Na+, NH4+, K+, NO3-, Cl-, SO42-) and organic (HCOO-, CH3COO-, C2H5COO-, C2O42-) ions, using ion chromatography. The 530 collected rain events represent a total of 5706.1 mm of rainfall compared to the measured pluviometry 6138.9 mm, indicating that the collection efficiency is about 93%. The order of total annual loading rates for soluble cations is NH4+ > Ca2+ > Mg2+ > K+. For soluble anions the order of loading is carbonates > HCOO- > NO3- > CH3COO- > SO42- > Cl- > C2O42- > C2H5COO-. In the wet savanna of Djougou, 86% of the measured pH values range between 4.7 and 5.7 with a median pH of 5.19, corresponding to a VWM (Volume Weighed Mean) H+ concentration of 6.46 μeq·L-1. This acidity results from a mixture of mineral and organic acids. The annual sea salt contribution was computed for K+, Mg2+, Ca2+ and SO42- and represents 4.2% of K+, 41% of Mg2+, 1.3% of Ca2+, and 7.4% of SO42-. These results show that K+, Ca2+, SO42-, and Mg2+ were mainly of non-marine origin. The marine contribution is estimated at 9%. The results of the chemical composition of rainwater of Djougou indicates that, except for the carbonates, ammonium has the highest VWM concentration (14.3 μeq·L-1) and nitrate concentration is 8.2 μeq·L-1. The distribution of monthly VWM concentration for all ions is computed and shows the highest values during the dry season, comparing to the wet season. Identified nitrogenous compound sources (NOx and NH3) are domestic animals, natural emissions from savanna soils, biomass

  3. Wetting behavior of mixtures of water and nonionic polyoxyethylene alcohol. (United States)

    Wu, Chih-Kang; Chen, Li-Jen


    Five binary water + C4Ej mixtures, water + n-C4E0, water + 2-C4E0, water + iso-C4E0, water + n-C4E1, and water + iso-C4E1, were chosen to perform the surface/interfacial tension measurements over the experimental temperature range from 10 to 85 degrees C at the normal pressure by using a homemade pendent drop/bubble tensiometer. The symbol CiEj is the abbreviation of a nonionic polyoxyethylene alcohol CiH(2i+1)(OCH2CH2)jOH. The wetting behavior of the CiEj-rich phase at the interface separating gas and the aqueous phase is systematically examined according to the wetting coefficient resulting from the experimental data of surface/interfacial tensions measurements. For those systems with a lower critical solution temperature, for example, water + n-C6E2, water + n-C4E1, and water + iso-C4E1, a wetting transition from partial wetting to nonwetting is always observed when the system is brought to close to its lower critical solution temperature. On the other hand, to start with a partial wetting CiEj-rich phase, a wetting transition from partial wetting to complete wetting is always observed when the system is driven to approach its upper critical solution temperature. The effect of hydrophobicity of CiEj on the wetting behavior of the CiEj-rich phase at the interface separating gas and the aqueous phase was carefully investigated by using five sets of mixtures: (1) water + n-C4E0, water + n-C5E0, and water + n-C6E0; (2) water + 2-C4E0 and water + 2-C5E0; (3) water + 2-C4E0 and water + n-C4E0; (4) water + n-C4E1, water + n-C5E1, and water + n-C6E1; (5) water + n-C4E0 and water + n-C4E1. The CiEj-rich phase would tend to drive away from complete wetting (or nonwetting) to partial wetting with an increase in the hydrophobicity of CiEj in the binary water + CiEj system. All the wetting behavior observed in the water + CiEj mixtures is consistent with the prediction of the critical point wetting theory of Cahn.

  4. Understanding Maple

    CERN Document Server

    Thompson, Ian


    Maple is a powerful symbolic computation system that is widely used in universities around the world. This short introduction gives readers an insight into the rules that control how the system works, and how to understand, fix, and avoid common problems. Topics covered include algebra, calculus, linear algebra, graphics, programming, and procedures. Each chapter contains numerous illustrative examples, using mathematics that does not extend beyond first-year undergraduate material. Maple worksheets containing these examples are available for download from the author's personal website. The book is suitable for new users, but where advanced topics are central to understanding Maple they are tackled head-on. Many concepts which are absent from introductory books and manuals are described in detail. With this book, students, teachers and researchers will gain a solid understanding of Maple and how to use it to solve complex mathematical problems in a simple and efficient way.

  5. New 'wet and dry' coolers; Neuentwicklung von Wet- und Dry-Kuehlern

    Energy Technology Data Exchange (ETDEWEB)

    Filippini, S.; Macchi, E.; Merlo, U. [LU-VE CONTARDO S.p.A., Uboldo (Italy)


    'Wet and dry' coolers are the result of a 4-year research programme. Theoretical fundamentals of heat transfer with and without water spraying are presented to begin with, as are the method of calculation using innovative FLUENTL software, and the experimental result. 'Wet and dry' systems consist of one or several chillers and a water conditioning system. They function as conventional dry coolers as long as the ambient temperature is low enough to ensure the required cooling water temperature. As the ambient temperature increases, demineralised water is sprayed onto the heat exchanger surface. The system has the following advantages as compared to conventional evaporation systems: (a) Water consumption is reduced significantly as water is required only during a limited period of the year; (b) Nearly complete evaporation of the sprayed water without water circulation, i.e. no collector basin is required below the heat exchanger. (c) Environment-friendliness: No undesired plumes, no health risk (e.g. legionellosis) from open basins of warm water, no residual droplets; (d) Automatic control minimises energy and water consumption in all seasons. (orig.) [German] Die Unterlage beschreibt die Ergebnisse eines vierjaehrigen Forschungsprogramms fuer die Entwicklung der extrem innovativen ''Wet-and-Dry''-Produktreihe. Es werden eingangs die wichtigsten theoretischen Grundlagen des Waermeuebergangs mit bzw. ohne Spruehwassereinsatz vorgestellt, die Berechnungsmethodologie mit innovativer FLUENT-Software und das experimentelle Ergebnis. Das ''Wet-and-Dry''-System besteht aus einem oder mehreren Kuehlern und einem Gesamtwasseraufbereitungssystem. Diese Produkte arbeiten als herkoemmliche ''Trocken-''Kuehler, solange die Aussentemperatur niedrig genug ist, um die verlangte Kuehlwassertemperatur zu gewaehrleisten. Wenn die Umgebungstemperatur steigt, wird entmineralisiertes Wasser auf die

  6. Uranium recovery from wet process phosphoric acid

    International Nuclear Information System (INIS)

    Carrington, O.F.; Pyrih, R.Z.; Rickard, R.S.


    Improvement in the process for recovering uranium from wetprocess phosphoric acid solution derived from the acidulation of uraniferous phosphate ores by the use of two ion exchange liquidliquid solvent extraction circuits in which in the first circuit (A) the uranium is reduced to the uranous form; (B) the uranous uranium is recovered by liquid-liquid solvent extraction using a mixture of mono- and di-(Alkyl-phenyl) esters of orthophosphoric acid as the ion exchange agent; and (C) the uranium oxidatively stripped from the agent with phosphoric acid containing an oxidizing agent to convert uranous to uranyl ions, and in the second circuit (D) recovering the uranyl uranium from the strip solution by liquid-liquid solvent extraction using di(2ethylhexyl)phosphoric acid in the presence of trioctylphosphine oxide as a synergist; (E) scrubbing the uranium loaded agent with water; (F) stripping the loaded agent with ammonium carbonate, and (G) calcining the formed ammonium uranyl carbonate to uranium oxide, the improvement comprising: (1) removing the organics from the raffinate of step (B) before recycling the raffinate to the wet-process plant, and returning the recovered organics to the circuit to substantially maintain the required balance between the mono and disubstituted esters; (2) using hydogren peroxide as the oxidizing agent in step (C); (3) using an alkali metal carbonate as the stripping agent in step (F) following by acidification of the strip solution with sulfuric acid; (4) using some of the acidified strip solution as the scrubbing agent in step (E) to remove phosphorus and other impurities; and (5) regenerating the alkali metal loaded agent from step (F) before recycling it to the second circuit

  7. Understanding physics

    CERN Document Server

    Mansfield, Michael


    Understanding Physics - Second edition is a comprehensive, yet compact, introductory physics textbook aimed at physics undergraduates and also at engineers and other scientists taking a general physics course. Written with today's students in mind, this text covers the core material required by an introductory course in a clear and refreshing way. A second colour is used throughout to enhance learning and understanding. Each topic is introduced from first principles so that the text is suitable for students without a prior background in physics. At the same time the book is designed to enable

  8. Rinsing of wafers after wet processing: Simulation and experiments (United States)

    Chiang, Chieh-Chun

    In semiconductor manufacturing, a large amount (50 billion gallons for US semiconductor fabrication plants in 2006) of ultrapure water (UPW) is used to rinse wafers after wet chemical processing to remove ionic contaminants on surfaces. Of great concern are the contaminants left in narrow (tens of nm), high-aspect-ratio (5:1 to 20:1) features (trenches, vias, and contact holes). The International Technology Roadmap for Semiconductors (ITRS) stipulates that ionic contaminant levels be reduced to below ˜ 10 10 atoms/cm2. Understanding the bottlenecks in the rinsing process would enable conservation of rinse water usage. A comprehensive process model has been developed on the COMSOL platform to predict the dynamics of rinsing of narrow structures on patterned SiO 2 substrates initially cleaned with NH4OH. The model considers the effect of various mass-transport mechanisms, including convection and diffusion/dispersion, which occur simultaneously with various surface phenomena, such as adsorption and desorption of impurities. The influences of charged species in the bulk and on the surface, and their induced electric field that affect both transport and surface interactions, have been addressed. Modeling results show that the efficacy of rinsing is strongly influenced by the rate of desorption of adsorbed contaminants, mass transfer of contaminants from the mouth of the feature to the bulk liquid, and the trench aspect ratio. Detection of the end point of rinsing is another way to conserve water used for rinsing after wet processing. The applicability of electrochemical impedance spectroscopy (EIS) to monitor rinsing of Si processed in HF with and without copper contaminant was explored. In the first study, the effect of the nature of surface state (flat band, depletion, or accumulation) of silicon on rinsing rate was investigated. The experimental results show that the state of silicon could affect rinsing kinetics through modulation of ion adsorption. In the second

  9. Double-barreled wet colostomy: urinary and fecal diversion. (United States)

    Kecmanovic, Dragutin M; Pavlov, Maja J; Ceranic, Miljan S; Masulovic, Dragan M; Popov, Ivan P; Micev, Marjan T


    Double-barreled wet colostomy represents simultaneous urinary and fecal surgical diversion performed most commonly after pelvic exenteration as a palliative procedure or after actinic damage. We report the structural and functional results of double-barreled wet colostomy with special attention to surgical technique, morbidity and functional results compared to those described in the available literature. We retrospectively followed 38 patients who underwent double-barreled wet colostomy at our institution from April 2003 to November 2007. The parameters were patient age and gender, the indication for double-barreled wet colostomy, postoperative morbidity and mortality, length of hospital stay and functional assessment by excreting excretory urography. A total of 38 double-barreled wet colostomies were performed at our institution, including 24 following total pelvic exenteration, 14 without resection, 9 in inoperable tumor cases and 5 in actinic damage cases. The postoperative morbidity rate was 15.7% with no treatment related mortality. Two patients had late postoperative complications, including stenosis of the ureterocolonic anastomosis and conduit necrosis, respectively. In our experience double-barreled wet colostomy has an acceptable morbidity and mortality rate, is performed without technical difficulties and does not require prolonged operative time. Double-barreled wet colostomy represents the procedure of choice in patients who require concurrent urinary and fecal diversion.

  10. Monitoring Technology Meets Care Work: Challenges of monitoring wet-beds in a nursing home. (United States)

    Kanstrup, Anne Marie; Bygholm, Ann


    Monitoring technology, especially sensor-based technology, is increasingly taken into use in care work. Despite the simplicity of these technologies - aimed to automate what appear as mundane monitoring tasks - recent research has identified major challenges primarily related to the technology's ability to meet the complexity of care work. Understanding intersectional challenges between these care technologies and care work is fundamental to improve design and use of health informatics. In this paper we present an analysis of interaction challenges between a wet-sensor at the task of monitoring wet beds at a nursing home. The analysis identifies the multifaceted nature of monitoring work and the intricacy of integrating sensor technology into the complex knowledge system of monitoring work.

  11. Effect of Wetting and Contamination of Granular Beds During Sphere Impact

    KAUST Repository

    Kouraytem, Nadia


    This thesis presents results from an experimental study of the impact of dense solid spheres onto granular beds. The overall aim is to further our understanding of the dynamical response of granular materials to impact. In order to do this, we will study both the initial penetration stages and peak acceleration exerted on the sphere by using high-speed imaging. Another critical part is to measure the penetration depth of the sphere and calculate the corresponding depth-averaged stopping force. Both of these main focal points will be assessed for not only dry, but wet and “contaminated” grains, whereby the granular bed will be comprised of two distinct size ranges of base grains. In doing so, we aim to broadly determine whether contaminated grains or wet grains are more effective at increasing the tensile strength of granular materials.

  12. Viscoelastic and poroelastic effects in the wetting dynamics of soft gels by liquids (United States)

    Limat, Laurent; Dervaux, Julien; Roche, Matthieu; Zhao, Menghua; Narita, Tetsuharu; Lequeux, Francois


    We have developed experiments and modeling of elastowetting dynamics on soft gels. First, wetting is very sensitive to the thickness of the gel, when deposited on a rigid basis. We reconsidered Long et al. approach, and extended it to finite depth. This yields a new scaling law, at low thickness, for dynamic contact angle, in very good agreement with experiment but not consistent with recent approachs assuming Neuman triangle to hold even in the dynamics. In a second step, we examined solvent migration in the bulk of the gel, and showed that poroelasticity is an essential ingredient to understand old unsolved issues (hysteresis on elastomers by Extrand and Kumagai), as well as recent puzzling measurements (long life footprints left by drops). Our calculations lead to ridges at the contact lines evolving logarithmically with time, with a very strong infuence on wetting properties of soft materials, and with possible applications to biophysics.

  13. Friction between footwear and floor covered with solid particles under dry and wet conditions. (United States)

    Li, Kai Way; Meng, Fanxing; Zhang, Wei


    Solid particles on the floor, both dry and wet, are common but their effects on the friction on the floor were seldom discussed in the literature. In this study, friction measurements were conducted to test the effects of particle size of solid contaminants on the friction coefficient on the floor under footwear, floor, and surface conditions. The results supported the hypothesis that particle size of solids affected the friction coefficient and the effects depended on footwear, floor, and surface conditions. On dry surfaces, solid particles resulted in friction loss when the Neolite footwear pad was used. On the other hand, solid particles provided additional friction when measured with the ethylene vinyl acetate (EVA) footwear pad. On wet surfaces, introducing solid particles made the floors more slip-resistant and such effects depended on particle size. This study provides information for better understanding of the mechanism of slipping when solid contaminants are present.

  14. Understanding Energy (United States)

    Menon, Deepika; Shelby, Blake; Mattingly, Christine


    "Energy" is a term often used in everyday language. Even young children associate energy with the food they eat, feeling tired after playing soccer, or when asked to turn the lights off to save light energy. However, they may not have the scientific conceptual understanding of energy at this age. Teaching energy and matter could be…

  15. Condensation and Wetting Dynamics on Micro/Nano-Structured Surfaces (United States)

    Olceroglu, Emre

    Because of their adjustable wetting characteristics, micro/nanostructured surfaces are attractive for the enhancement of phase-change heat transfer where liquid-solid-vapor interactions are important. Condensation, evaporation, and boiling processes are traditionally used in a variety of applications including water harvesting, desalination, industrial power generation, HVAC, and thermal management systems. Although they have been studied by numerous researchers, there is currently a lack of understanding of the underlying mechanisms by which structured surfaces improve heat transfer during phase-change. This PhD dissertation focuses on condensation onto engineered surfaces including fabrication aspect, the physics of phase-change, and the operational limitations of engineered surfaces. While superhydrophobic condensation has been shown to produce high heat transfer rates, several critical issues remain in the field. These include surface manufacturability, heat transfer coefficient measurement limitations at low heat fluxes, failure due to surface flooding at high supersaturations, insufficient modeling of droplet growth rates, and the inherent issues associated with maintenance of non-wetted surface structures. Each of these issues is investigated in this thesis, leading to several contributions to the field of condensation on engineered surfaces. A variety of engineered surfaces have been fabricated and characterized, including nanostructured and hierarchically-structured superhydrophobic surfaces. The Tobacco mosaic virus (TMV) is used here as a biological template for the fabrication of nickel nanostructures, which are subsequently functionalized to achieve superhydrophobicity. This technique is simple and sustainable, and requires no applied heat or external power, thus making it easily extendable to a variety of common heat transfer materials and complex geometries. To measure heat transfer rates during superhydrophobic condensation in the presence of non

  16. Modelling of wetting tests for a natural pyroclastic soil

    Directory of Open Access Journals (Sweden)

    Moscariello Mariagiovanna


    Full Text Available The so-called wetting-induced collapse is one of the most common problems associated with unsaturated soils. This paper applies the Modified Pastor-Zienkiewicz model (MPZ to analyse the wetting behaviour of undisturbed specimens of an unsaturated air-fall volcanic (pyroclastic soil originated from the explosive activity of the Somma-Vesuvius volcano (Southern Italy. Both standard oedometric tests, suction-controlled oedometeric tests and suction-controlled isotropic tests are considered. The results of the constitutive modelling show a satisfactory capability of the MPZ to simulate the variations of soil void ratio upon wetting, with negligible differences among the measured and the computed values.

  17. Partial wetting gas-liquid segmented flow microreactor. (United States)

    Kazemi Oskooei, S Ali; Sinton, David


    A microfluidic reactor strategy for reducing plug-to-plug transport in gas-liquid segmented flow microfluidic reactors is presented. The segmented flow is generated in a wetting portion of the chip that transitions downstream to a partially wetting reaction channel that serves to disconnect the liquid plugs. The resulting residence time distributions show little dependence on channel length, and over 60% narrowing in residence time distribution as compared to an otherwise similar reactor. This partial wetting strategy mitigates a central limitation (plug-to-plug dispersion) while preserving the many attractive features of gas-liquid segmented flow reactors.

  18. Understanding Microstructural Properties of Perovskite Ceramics through Their Wet-Chemical Synthesis

    NARCIS (Netherlands)

    Stawski, Tomasz


    This thesis comprises of seven full research chapters on the morphology, properties and processing of sol-gel precursor systems of barium titanate and lead zirconate titanate thin films and powders. In all the considered problems, the synthesis leading to nano-sized perovskite ceramics constitutes

  19. The Balkan wet grassland vegetation: a prerequisite to better understanding of European habitat diversity

    Czech Academy of Sciences Publication Activity Database

    Hájek, Michal; Hájková, Petra; Sopotlieva, D.; Apostolova, I.; Velev, N.


    Roč. 195, č. 2 (2008), s. 197-213 ISSN 1385-0237 Grant - others:GA AV ČR(CZ) KJB6163302 Institutional research plan: CEZ:AV0Z60050516 Keywords : climate * vegetation * grasslands Subject RIV: EF - Botanics Impact factor: 1.730, year: 2008

  20. Understanding microstructural evolution of mixed metal-oxide silsesquioxane glasses through wet-chemical synthesis

    NARCIS (Netherlands)

    Besselink, R.


    Membrane separation offers energy efficient alternatives for distillation in separation of small molecules. Among a large variety of materials that can be used, microporous hybrid silica membranes are (1) suitable for the separation of the smallest molecules eg: H2/N2, (2) have a superior

  1. Surface Modifications in Adhesion and Wetting (United States)

    Longley, Jonathan

    Advances in surface modification are changing the world. Changing surface properties of bulk materials with nanometer scale coatings enables inventions ranging from the familiar non-stick frying pan to advanced composite aircraft. Nanometer or monolayer coatings used to modify a surface affect the macro-scale properties of a system; for example, composite adhesive joints between the fuselage and internal frame of Boeing's 787 Dreamliner play a vital role in the structural stability of the aircraft. This dissertation focuses on a collection of surface modification techniques that are used in the areas of adhesion and wetting. Adhesive joints are rapidly replacing the familiar bolt and rivet assemblies used by the aerospace and automotive industries. This transition is fueled by the incorporation of composite materials into aircraft and high performance road vehicles. Adhesive joints have several advantages over the traditional rivet, including, significant weight reduction and efficient stress transfer between bonded materials. As fuel costs continue to rise, the weight reduction is accelerating this transition. Traditional surface pretreatments designed to improve the adhesion of polymeric materials to metallic surfaces are extremely toxic. Replacement adhesive technologies must be compatible with the environment without sacrificing adhesive performance. Silane-coupling agents have emerged as ideal surface modifications for improving composite joint strength. As these coatings are generally applied as very thin layers (compression of a water drop between two gradient surfaces. This inchworm type motion is studied in detail and offers an alternative method to surface vibration for moving drops in microfluidic devices. The final surface modification considered is the application of a thin layer of rubber to a rigid surface. While this technique has many practical uses, such as easy release coatings in marine environments, it is applied herein to enable spontaneous

  2. Wet high-intensity magnetic separation

    International Nuclear Information System (INIS)

    Levin, J.; Shanks, R.I.


    Miscellaneous laboratory tests (most of them on cyanide residues) were undertaken to supplement on-site pilot-plant work on wet high intensity magnetic separation (WHIMS). Initially, the main concern was with blockage of the matrix, and consideration was given to the use of a reverse-flushing system. The laboratory tests on this system were encouraging, but they were not of sufficiently long duration to be conclusive. The velocity of the pulp through the matrix is important, because it determines the capacity of the separator and the recovery obtainable. Of almost equal importance is the magnetic load, which affects the velocity of the pulp and the recovery. Typically, a recovery of 51 per cent of the uranium was reduced to one of 40 per cent as the magnetic load was increased from 25 to 100 g/l, while the pulp velocity decreased from 62 to 36 mm/s. There was some indication that, for the same pulp velocity, lower recoveries are obtained when free-fall feeding is used. Some benefit was observed in the application of WHIMS to coarsely ground ore; from a Blyvooruitzicht rod-mill product, 25 per cent of the total uranium was recovered when only 29 per cent of the rod-mill product (the finest portion) was treated. A similar recovery was made from 43 per cent of the rod-mill product from Stilfontein; a second stage of treatment after regrinding raised the overall recovery of uranium to 76,4 per cent. Recoveries of 55 and 42 per cent of the uranium were obtained in tests on two flotation tailings from Free State Geduld. In a determination of the mass magnetic susceptibilities of the constituents in a typical concentrate obtained by WHIMS, it was found that some 20 per cent of the magnetic product had a susceptibility of less than 5,4 X 10 -6 e.m.u. but contained 38 per cent of the uranium recovered by WHIMS. A few tests were conducted on different types of matrix. A matrix of spaced horizontal rods is recommended for possible future consideration [af

  3. Understanding translation

    DEFF Research Database (Denmark)

    Schjoldager, Anne Gram; Gottlieb, Henrik; Klitgård, Ida

    Understanding Translation is designed as a textbook for courses on the theory and practice of translation in general and of particular types of translation - such as interpreting, screen translation and literary translation. The aim of the book is to help you gain an in-depth understanding...... of the phenomenon of translation and to provide you with a conceptual framework for the analysis of various aspects of professional translation. Intended readers are students of translation and languages, but the book will also be relevant for others who are interested in the theory and practice of translation...... - translators, language teachers, translation users and literary, TV and film critics, for instance. Discussions focus on translation between Danish and English....

  4. Understanding Resilience

    Directory of Open Access Journals (Sweden)

    Gang eWu


    Full Text Available Resilience is the ability to adapt successfully in the face of stress and adversity. Stressful life events, trauma and chronic adversity can have a substantial impact on brain function and structure, and can result in the development of PTSD, depression and other psychiatric disorders. However, most individuals do not develop such illnesses after experiencing stressful life events, and are thus thought to be resilient. Resilience as successful adaptation relies on effective responses to environmental challenges and ultimate resistance to the deleterious effects of stress, therefore a greater understanding of the factors that promote such effects is of great relevance. This review focuses on recent findings regarding genetic, epigenetic, developmental, psychosocial and neurochemical factors that are considered essential contributors to the development of resilience. Neural circuits and pathways involved in mediating resilience are also discussed. The growing understanding of resilience factors will hopefully lead to the development of new pharmacological and psychological interventions for enhancing resilience and mitigating the untoward consequences.

  5. Understand electronics

    CERN Document Server

    Bishop, Owen


    Understand Electronics provides a readable introduction to the exciting world of electronics for the student or enthusiast with little previous knowledge. The subject is treated with the minimum of mathematics and the book is extensively illustrated.This is an essential guide for the newcomer to electronics, and replaces the author's best-selling Beginner's Guide to Electronics.The step-by-step approach makes this book ideal for introductory courses such as the Intermediate GNVQ.

  6. Understanding users

    DEFF Research Database (Denmark)

    Johannsen, Carl Gustav Viggo


    Segmentation of users can help libraries in the process of understanding user similarities and differences. Segmentation can also form the basis for selecting segments of target users and for developing tailored services for specific target segments. Several approaches and techniques have been...... segmentation project using computer-generated clusters. Compared to traditional marketing texts, this article also tries to identify user segments or images or metaphors by the library profession itself....

  7. Understanding unemployment


    Guillaume Rocheteau


    Modern economists have built models of the labor market, which isolate the market’s key drivers and describe the way these interact to produce particular levels of unemployment. One of the most popular models used by macroeconomists today is the search-matching model of equilibrium unemployment. We explain this model, and show how it can be applied to understand the way various policies, such as unemployment benefits, taxes, or technological changes, can affect the unemployment rate.

  8. Understanding Technology?

    Directory of Open Access Journals (Sweden)

    Erik Bendtsen


    Full Text Available We are facing radical changes in our ways of living in the nearest future. Not necessarily of our own choice, but because tchnological development is moving so fast, that it will have still greater impact on many aspects of our lives. We have seen the beginnings of that change within the latest 35 years or so, but according to newest research that change will speed up immensely in the nearest years to come. The impact of that change or these changes will affect our working life immensely as a consequence of automation. How these changes are brought about and which are their consequences in a broad sense is being attempted to be understood and guessed by researchers. No one knows for sure, but specific patterns are visible. This paper will not try to guess, what will come, but will rather try to understand the deepest ”nature” of technology in order to understand the driving factors in this development: the genesis of technology in a broad sense in order to contibute to the understanding of the basis for the expected development.

  9. From soaking wet to bone dry

    DEFF Research Database (Denmark)

    Båstrup-Spohr, Lars; Sand-Jensen, Kaj; Nicolajsen, Sascha Veggerby


    Question Why do plants grow where they grow? Prediction of species' occurrence and abundance in relation to the environment is a core aim of ecology, as is understanding the link between environmental stressors and adaptive traits. Community assembly may be viewed as a sequence of filters, sortin...

  10. The biology of skin wetness perception and its implications in manual function and for reproducing complex somatosensory signals in neuroprosthetics (United States)

    Ackerley, Rochelle


    Our perception of skin wetness is generated readily, yet humans have no known receptor (hygroreceptor) to signal this directly. It is easy to imagine the sensation of water running over our hands or the feel of rain on our skin. The synthetic sensation of wetness is thought to be produced from a combination of specific skin thermal and tactile inputs, registered through thermoreceptors and mechanoreceptors, respectively. The present review explores how thermal and tactile afference from the periphery can generate the percept of wetness centrally. We propose that the main signals include information about skin cooling, signaled primarily by thinly myelinated thermoreceptors, and rapid changes in touch, through fast-conducting, myelinated mechanoreceptors. Potential central sites for integration of these signals, and thus the perception of skin wetness, include the primary and secondary somatosensory cortices and the insula cortex. The interactions underlying these processes can also be modeled to aid in understanding and engineering the mechanisms. Furthermore, we discuss the role that sensing wetness could play in precision grip and the dexterous manipulation of objects. We expand on these lines of inquiry to the application of the knowledge in designing and creating skin sensory feedback in prosthetics. The addition of real-time, complex sensory signals would mark a significant advance in the use and incorporation of prosthetic body parts for amputees in everyday life. PMID:28123008

  11. Physiological wet laboratory facilities in colleges of nursing. (United States)

    Schaffer, Susan; Yucha, Carolyn B


    The purpose of this study was to describe physiological wet laboratories as they exist within colleges of nursing with doctoral programs. Surveys were sent to the current deans and directors of all 96 nursing colleges/schools with doctoral programs as of January 2004, obtained from the American Association of Colleges of Nursing Web site. Only 26 (37%) of 71 responding schools operate their own wet laboratory, either singly or with another college. The most common analyses done are hormone levels, immune proteins, and cell counts, followed by catecholamines, chemistries, and bacterial cultures. Approximate annual costs of running wet laboratories range from 1,500 dollars to 320,000 dollars per school. Schools based in an academic health center were more likely to operate a wet laboratory ( chi2 = .003). There were no differences based on source of university funding (public vs. private) or Carnegie classification.

  12. SAFARI 2000 PAR Measurements, Kalahari Transect, Botswana, Wet Season 2000 (United States)

    National Aeronautics and Space Administration — ABSTRACT: Ceptometer data from a Decagon AccuPAR (Model PAR-80) were collected at four sites in Botswana during the SAFARI 2000 Kalahari Transect Wet Season Campaign...


    Directory of Open Access Journals (Sweden)



    Full Text Available The experiment used 240 Landrace pigs assigned to 3 groups. The control group received ground dry feed; group 1 received wet feed 1/1, while group 2 received pelleted feed. The compound feeds were assayed with the Weende method. Compared to the control group, the 60 kg weight was reached three days later by the animals with wet feeding and four days earlier by the animals receiving pelleted feed. At the wet feeding, the average daily gain was 484 g, near control group (p ≤ 0.05 and the feed conversion ratio was 8.9% lower. Wet feeding is an economic alternative for pig feeding during heir first fattening stage, improving the local microclimate by the generation of less powders.

  14. The Geologic Evidence for a Warm and Wet Early Mars (United States)

    Craddock, R. A.; Irwin, R. P.; Howard, A. D.; Morgan, A. M.


    The geologic evidence supporting a warm and wet climate on early Mars is presented. The case against an "icy highlands" scenario is also made. Climate models are converging to a solution, but any theoretical data must explain the empirical data.

  15. ROE Wet Sulfate Deposition Raster 2011-2013 (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet sulfate deposition in kilograms per hectare from 2011 to 2013. Summary data in this indicator were provided by EPA’s...

  16. ROE Wet Sulfate Deposition Raster 1989-1991 (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet sulfate deposition in kilograms per hectare from 1989 to 1991. Summary data in this indicator were provided by EPA’s...

  17. Thermo-fluid dynamic analysis of wet compression process

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, Abhay; Kim, Heuy Dong [School of Mechanical Engineering, Andong National University, Andong (Korea, Republic of); Chidambaram, Palani Kumar [FMTRC, Daejoo Machinery Co. Ltd., Daegu (Korea, Republic of); Suryan, Abhilash [Dept. of Mechanical Engineering, College of Engineering Trivandrum, Kerala (India)


    Wet compression systems increase the useful power output of a gas turbine by reducing the compressor work through the reduction of air temperature inside the compressor. The actual wet compression process differs from the conventional single phase compression process due to the presence of latent heat component being absorbed by the evaporating water droplets. Thus the wet compression process cannot be assumed isentropic. In the current investigation, the gas-liquid two phase has been modeled as air containing dispersed water droplets inside a simple cylinder-piston system. The piston moves in the axial direction inside the cylinder to achieve wet compression. Effects on the thermodynamic properties such as temperature, pressure and relative humidity are investigated in detail for different parameters such as compression speeds and overspray. An analytical model is derived and the requisite thermodynamic curves are generated. The deviations of generated thermodynamic curves from the dry isentropic curves (PV{sup γ} = constant) are analyzed.

  18. Thermo-fluid dynamic analysis of wet compression process

    International Nuclear Information System (INIS)

    Mohan, Abhay; Kim, Heuy Dong; Chidambaram, Palani Kumar; Suryan, Abhilash


    Wet compression systems increase the useful power output of a gas turbine by reducing the compressor work through the reduction of air temperature inside the compressor. The actual wet compression process differs from the conventional single phase compression process due to the presence of latent heat component being absorbed by the evaporating water droplets. Thus the wet compression process cannot be assumed isentropic. In the current investigation, the gas-liquid two phase has been modeled as air containing dispersed water droplets inside a simple cylinder-piston system. The piston moves in the axial direction inside the cylinder to achieve wet compression. Effects on the thermodynamic properties such as temperature, pressure and relative humidity are investigated in detail for different parameters such as compression speeds and overspray. An analytical model is derived and the requisite thermodynamic curves are generated. The deviations of generated thermodynamic curves from the dry isentropic curves (PV γ = constant) are analyzed

  19. SAFARI 2000 Leaf Spectral Measurements, Kalahari Transect, Wet Season 2000 (United States)

    National Aeronautics and Space Administration — The Boston University team collected several data sets along the Kalahari Transect during the SAFARI 2000 wet season field campaign between March 3 and March 18,...

  20. SAFARI 2000 Leaf Spectral Measurements, Kalahari Transect, Wet Season 2000 (United States)

    National Aeronautics and Space Administration — ABSTRACT: The Boston University team collected several data sets along the Kalahari Transect during the SAFARI 2000 wet season field campaign between March 3 and...

  1. Mercury Wet Scavenging and Deposition Differences by Precipitation Type. (United States)

    Kaulfus, Aaron S; Nair, Udaysankar; Holmes, Christopher D; Landing, William M


    We analyze the effect of precipitation type on mercury wet deposition using a new database of individual rain events spanning the contiguous United States. Measurements from the Mercury Deposition Network (MDN) containing single rainfall events were identified and classified into six precipitation types. Mercury concentrations in surface precipitation follow a power law of precipitation depth that is modulated by precipitation system morphology. After controlling for precipitation depth, the highest mercury deposition occurs in supercell thunderstorms, with decreasing deposition in disorganized thunderstorms, quasi-linear convective systems (QLCS), extratropical cyclones, light rain, and land-falling tropical cyclones. Convective morphologies (supercells, disorganized, and QLCS) enhance wet deposition by a factor of at least 1.6 relative to nonconvective morphologies. Mercury wet deposition also varies by geographic region and season. After controlling for other factors, we find that mercury wet deposition is greater over high-elevation sites, seasonally during summer, and in convective precipitation.

  2. Bioaccumulation of heavy metals in two wet retention ponds

    DEFF Research Database (Denmark)

    Søberg, Laila C.; Vollertsen, Jes; Blecken, Godecke-Tobias


    Metal accumulation in stormwater ponds may contaminate the inhabiting fauna, thus jeopardizing their ecosystem servicing function. We evaluated bioaccumulation of metals in natural fauna and caged mussel indicator organisms in two wet retention ponds. Mussel cages were distributed throughout the ...

  3. In silico and wet lab approaches to study transcriptional regulation

    NARCIS (Netherlands)

    Hestand, Matthew Scott


    Gene expression is a complicated process with multiple types of regulation, including binding of proteins termed transcription factors. This thesis looks at transcription factors and transcription factor binding site discovery through computational predictions and wet lab work to better elucidate

  4. SAFARI 2000 PAR Measurements, Kalahari Transect, Botswana, Wet Season 2000 (United States)

    National Aeronautics and Space Administration — Ceptometer data from a Decagon AccuPAR (Model PAR-80) were collected at four sites in Botswana during the SAFARI 2000 Kalahari Transect Wet Season Campaign (March,...

  5. Microbial community composition of transiently wetted Antarctic Dry Valley soils. (United States)

    Niederberger, Thomas D; Sohm, Jill A; Gunderson, Troy E; Parker, Alexander E; Tirindelli, Joëlle; Capone, Douglas G; Carpenter, Edward J; Cary, Stephen C


    During the summer months, wet (hyporheic) soils associated with ephemeral streams and lake edges in the Antarctic Dry Valleys (DVs) become hotspots of biological activity and are hypothesized to be an important source of carbon and nitrogen for arid DV soils. Recent research in the DV has focused on the geochemistry and microbial ecology of lakes and arid soils, with substantially less information being available on hyporheic soils. Here, we determined the unique properties of hyporheic microbial communities, resolved their relationship to environmental parameters and compared them to archetypal arid DV soils. Generally, pH increased and chlorophyll a concentrations decreased along transects from wet to arid soils (9.0 to ~7.0 for pH and ~0.8 to ~5 μg/cm(3) for chlorophyll a, respectively). Soil water content decreased to below ~3% in the arid soils. Community fingerprinting-based principle component analyses revealed that bacterial communities formed distinct clusters specific to arid and wet soils; however, eukaryotic communities that clustered together did not have similar soil moisture content nor did they group together based on sampling location. Collectively, rRNA pyrosequencing indicated a considerably higher abundance of Cyanobacteria in wet soils and a higher abundance of Acidobacterial, Actinobacterial, Deinococcus/Thermus, Bacteroidetes, Firmicutes, Gemmatimonadetes, Nitrospira, and Planctomycetes in arid soils. The two most significant differences at the genus level were Gillisia signatures present in arid soils and chloroplast signatures related to Streptophyta that were common in wet soils. Fungal dominance was observed in arid soils and Viridiplantae were more common in wet soils. This research represents an in-depth characterization of microbial communities inhabiting wet DV soils. Results indicate that the repeated wetting of hyporheic zones has a profound impact on the bacterial and eukaryotic communities inhabiting in these areas.

  6. Specific features of aluminum nanoparticle water and wet air oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Lozhkomoev, Aleksandr S., E-mail:; Glazkova, Elena A., E-mail:; Svarovskaya, Natalia V., E-mail:; Bakina, Olga V., E-mail:; Kazantsev, Sergey O., E-mail:; Lerner, Marat I., E-mail: [National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)


    The oxidation processes of the electrically exploded aluminum nanopowders in water and in wet air are examined in the paper. The morphology of the intermediate reaction products of aluminum oxidation has been studied using the transmission electron microscopy. It was shown that the aluminum nanopowder water oxidation causes the formation of the hollow spheres with mesoporous boehmite nanosheets coating. The wedge-like bayerite particles are formed during aluminum nanopowder wet air oxidation.

  7. Human skin wetness perception: psychophysical and neurophysiological bases (United States)

    Filingeri, Davide; Havenith, George


    The ability to perceive thermal changes in the surrounding environment is critical for survival. However, sensing temperature is not the only factor among the cutaneous sensations to contribute to thermoregulatory responses in humans. Sensing skin wetness (i.e. hygrosensation) is also critical both for behavioral and autonomic adaptations. Although much has been done to define the biophysical role of skin wetness in contributing to thermal homeostasis, little is known on the neurophysiological mechanisms underpinning the ability to sense skin wetness. Humans are not provided with skin humidity receptors (i.e., hygroreceptors) and psychophysical studies have identified potential sensory cues (i.e. thermal and mechanosensory) which could contribute to sensing wetness. Recently, a neurophysiological model of human wetness sensitivity has been developed. In helping clarifying the peripheral and central neural mechanisms involved in sensing skin wetness, this model has provided evidence for the existence of a specific human hygrosensation strategy, which is underpinned by perceptual learning via sensory experience. Remarkably, this strategy seems to be shared by other hygroreceptor-lacking animals. However, questions remain on whether these sensory mechanisms are underpinned by specific neuromolecular pathways in humans. Although the first study on human wetness perception dates back to more than 100 years, it is surprising that the neurophysiological bases of such an important sensory feature have only recently started to be unveiled. Hence, to provide an overview of the current knowledge on human hygrosensation, along with potential directions for future research, this review will examine the psychophysical and neurophysiological bases of human skin wetness perception. PMID:27227008

  8. Evaluation of the effectiveness of coal and mine dust wetting

    Directory of Open Access Journals (Sweden)

    Krzysztof Cybulski


    This paper presents a method to evaluate the effectiveness of coal or mine dust's moistening conducted with the use of water solutions of wetting agents in order to deprive the dust of its volatility, is based on the method of measurement of time of complete moistening of that dust's one-gram samples with the use of “pure” water or water solutions of the particular wetting agent.

  9. Apparent de-wetting due to superfluid flow

    CERN Document Server

    Poujade, M; Rolley, E


    We have investigated the wetting behaviour of superfluid helium-4 on silicon. Surprisingly, we observe pseudo-de-wetting: though a thick superfluid film covers the substrate, the meniscus displays a finite contact angle which decreases from about 5 deg C at low temperature down to zero at the superfluid transition. We show that this behaviour can be explained by a pressure decrease due to a superfluid flow, closely related to the Kontorovich effect. (authors)

  10. Proteomic effects of wet cupping (Al-hijamah

    Directory of Open Access Journals (Sweden)

    Amer A. Almaiman


    Full Text Available Wet cupping (Al-hijamah is a therapeutic technique practiced worldwide as a part of the Unani system of medicine. It involves bloodletting from acupoints on a patient’s skin to produce a therapeutic outcome. A thorough review of research articles on wet cupping with relevance to proteomics field that are indexed by Google Scholar, PubMed, and/or Science Direct databases was performed. Eight original research articles were summarized in this paper. Overall, wet cupping did not have a significant effect on C-reactive protein, Hsp-27, sister chromatid exchanges, and cell replication index. In contrast, wet cupping was found to produce higher oxygen saturation, eliminate lactate from subcutaneous tissues, remove blood containing higher levels of malondialdehyde and nitric oxide, and produce higher activity of myeloperoxidase. The proteomic effects of wet cupping therapy have not been adequately investigated. Thus, future studies on wet cupping that use systemic and sound protocols to avoid bias should be conducted.

  11. Pipe flow of pumping wet shotcrete based on lubrication layer. (United States)

    Chen, Lianjun; Liu, Guoming; Cheng, Weimin; Pan, Gang


    Wet shotcrete can reduce dust and improve supporting strength, however, safe and efficient pipage is a key technical part of wet shotcrete process. The paper studied the pipe flow law of wet shotcrete based on lubrication layer by build the experimental pumping circuit of wet shotcrete that can carry out a number of full-scale pumping tests. The experimental results show there was a linear relationship between pressure loss and flow rate. Combined with the Buckingham rheological equation, the computing equations of the yield shear stress and plastic viscosity were deduced through linear regression. A simple analytical method allowing for a rough estimation of the pumping pressure was proposed and used when considering the lubrication layer of wet shotcrete in pipes. In addition, two kinds of particulate distributive models were established along the time axial to analyze the formation of lubrication layer which is related with particles migration. By computational fluid dynamics simulation, the lubrication layer thickness of different mix proportions was estimated. A new method for measuring the thickness of lubrication layer was proposed to verify it by binarization processing. Finally, according to the comparative analysis of experiments, simulation and computed value, it can be seen that the lubrication layer plays a key role in the process of wet shotcrete flow and with the increase of lubrication layer thickness pipe pressure declines gradually.

  12. Understanding uncertainty

    CERN Document Server

    Lindley, Dennis V


    Praise for the First Edition ""...a reference for everyone who is interested in knowing and handling uncertainty.""-Journal of Applied Statistics The critically acclaimed First Edition of Understanding Uncertainty provided a study of uncertainty addressed to scholars in all fields, showing that uncertainty could be measured by probability, and that probability obeyed three basic rules that enabled uncertainty to be handled sensibly in everyday life. These ideas were extended to embrace the scientific method and to show how decisions, containing an uncertain element, could be rationally made.

  13. Atmospheric wet and dry deposition of trace elements at 10 sites in Northern China (United States)

    Pan, Y. P.; Wang, Y. S.


    Atmospheric deposition is considered to be a major process that removes pollutants from the atmosphere and an important source of nutrients and contaminants for ecosystems. Trace elements (TEs), especially toxic metals deposited on plants and into soil or water, can cause substantial damage to the environment and human health due to their transfer and accumulation in food chains. Despite public concerns, quantitative knowledge of metal deposition from the atmosphere to ecosystems remains scarce. To advance our understanding of the spatiotemporal variations in the magnitudes, pathways, compositions and impacts of atmospherically deposited TEs, precipitation (rain and snow) and dry-deposited particles were collected simultaneously at 10 sites in Northern China from December 2007 to November 2010. The measurements showed that the wet and dry depositions of TEs in the target areas were orders of magnitude higher than previous observations within and outside China, generating great concern over the potential risks. The spatial distribution of the total (wet plus dry) deposition flux was consistent with that of the dry deposition, with a significant decrease from industrial and urban areas to suburban, agricultural and rural sites, while the wet deposition exhibited less spatial variation. In addition, the seasonal variation of wet deposition was also different from that of dry deposition, although they were both governed by the precipitation and emission patterns. For the majority of TEs that exist as coarse particles, dry deposition dominated the total flux at each site. This was not the case for potassium, nickel, arsenic, lead, zinc, cadmium, selenium, silver and thallium, for which the relative importance between wet and dry deposition fluxes varied by site. Whether wet deposition is the major atmospheric cleansing mechanism for the TEs depends on the size distribution of the particles. We found that atmospheric inputs of copper, lead, zinc, cadmium, arsenic and

  14. Atmospheric wet and dry deposition of trace elements at ten sites in Northern China (United States)

    Pan, Y. P.; Wang, Y. S.


    Atmospheric deposition is considered to be a major process that removes pollutants from the atmosphere and an important source of nutrients and contaminants for ecosystems. Trace elements (TEs), especially toxic metals deposited on plants and into soil and water, can cause substantial damage to the environment and human health due to their transfer and accumulation in food chains. Despite public concerns, quantitative knowledge of metal deposition from the atmosphere to ecosystems remains scarce. To advance our understanding of the spatio-temporal variations in the magnitudes, pathways, compositions and impacts of atmospherically deposited TEs, precipitation (rain and snow) and dry-deposited particles were collected simultaneously at ten sites in Northern China from December 2007 to November 2010. The measurements showed that the wet and dry depositions of TEs in the target areas were orders of magnitude higher than previous observations within and outside China, generating great concern over the potential risks. The spatial distribution of the total (wet plus dry) deposition flux was consistent with that of the dry deposition, with a significant decrease from industrial and urban areas to suburban, agricultural and rural sites. In contrast, the wet deposition exhibited less spatial variation. The seasonal variation of wet deposition was also different from that of dry deposition, although they were both governed by the precipitation and emission patterns. For the majority of TEs that exist as coarse particles, dry deposition dominated the total flux at each site. This was not the case for K, Ni, As, Pb, Zn, Cd, Se, Ag and Tl, for which the relative importance between wet and dry deposition fluxes varied by site. Whether wet deposition is the major atmospheric cleansing mechanism for the TEs depends on the size distribution and solubility of the particles. We found that atmospheric inputs of Cu, Pb, Zn, Cd, As and Se were of the same magnitude as their increases in

  15. Understanding analysis

    CERN Document Server

    Abbott, Stephen


    This lively introductory text exposes the student to the rewards of a rigorous study of functions of a real variable. In each chapter, informal discussions of questions that give analysis its inherent fascination are followed by precise, but not overly formal, developments of the techniques needed to make sense of them. By focusing on the unifying themes of approximation and the resolution of paradoxes that arise in the transition from the finite to the infinite, the text turns what could be a daunting cascade of definitions and theorems into a coherent and engaging progression of ideas. Acutely aware of the need for rigor, the student is much better prepared to understand what constitutes a proper mathematical proof and how to write one. Fifteen years of classroom experience with the first edition of Understanding Analysis have solidified and refined the central narrative of the second edition. Roughly 150 new exercises join a selection of the best exercises from the first edition, and three more project-sty...

  16. Understanding ayurveda. (United States)

    Gadgil, Vaidya Dilip


    Ayurveda needs to achieve its full potential both in India and globally. This requires imparting to its students full appreciation of Ayurveda's power and strength, particularly proper understanding of the advantages of applying it to treat chronic and acute diseases. To this end, we explain the necessity of learning Sanskrit as a medium of study, and the advantages of learning the Texts in the traditional way, rather than relying on translations with all the loss of meaning and precision, which that entails. We emphasize the use of Triskandhakosha as a means to fully understand Ayurveda fundamental concepts and technical terms, so that all their shades of meaning are fully understood, and all their usages given in different places in the texts. Only by such methods can full appreciation of Ayurvedic wisdom be achieved, and the full depth and power of its knowledge be applied. Only then will its true status among systems of medicine come to be appreciated, either in India or more widely in the world as a whole.

  17. Understanding Ayurveda

    Directory of Open Access Journals (Sweden)

    Vaidya Dilip Gadgil


    Full Text Available Ayurveda needs to achieve its full potential both in India and globally. This requires imparting to its students full appreciation of Ayurveda′s power and strength, particularly proper understanding of the advantages of applying it to treat chronic and acute diseases. To this end, we explain the necessity of learning Sanskrit as a medium of study, and the advantages of learning the Texts in the traditional way, rather than relying on translations with all the loss of meaning and precision, which that entails. We emphasize the use of Triskandhakosha as a means to fully understand Ayurveda fundamental concepts and technical terms, so that all their shades of meaning are fully understood, and all their usages given in different places in the texts. Only by such methods can full appreciation of Ayurvedic wisdom be achieved, and the full depth and power of its knowledge be applied. Only then will its true status among systems of medicine come to be appreciated, either in India or more widely in the world as a whole.

  18. Quantification of immiscible fluid distribution of an oil-wet and water-wet bead pack imaged using x-ray computed microtomography (United States)

    Landry, C. J.; Karpyn, Z. T.; Piri, M.


    history hysteresis and a zone of distinct saturation history hysteresis. The meniscus specific interfacial area of the fluids is shown to trend towards a maximum at a brine saturation of 0.25 to 0.40, in good agreement with previously reported values, regardless of saturation history and wettability. The total specific interfacial area of the fluids is shown to correlate linearly with non-wetting phase saturation, independent of fluid distribution zone, saturation history and wettability. The fluid-normalized specific interfacial areas are shown to be nearly constant, independent of saturation, saturation history and wettability. Furthermore a population analysis of individual blob volume, surface area, shape, aspect ratio and orientation provides insight into the effect of wettability on immiscible fluid microstructure. The agreement between our measurements and others conducted with natural soils, sands and rock cores is promising for furthering our understanding of how pore-scale processes influence macroscale properties used to describe multiphase flow and transport.

  19. Mechanical and microstructural properties of "wet" alginate and composite films containing various carbohydrates. (United States)

    Harper, B Allison; Barbut, Shai; Smith, Alexandra; Marcone, Massimo F


    Composite "wet" alginate films were manufactured from alginate-carbohydrate solutions containing 5% alginate and 0.25% pectin, carrageenan (kappa or iota), potato starch (modified or unmodified), gellan gum, or cellulose (extracted or commercial). The "wet" alginate films were used as a model to understand co-extruded alginate sausage casings that are currently being used by several sausage manufacturers. The mechanical, optical, and microstructural properties of the calcium cross-linked composite films were explored. In addition, the water holding capacity and textural profile analysis properties of the alginate-carbohydrate gels were studied. The results indicate that the mechanical properties of "wet" alginate films/casings can be modified by adding various carbohydrates to them. Alginate films with pectin, carrageenan, and modified potato starch had significantly (P < 0.05) greater elongation values than pure alginate films. The alginate-pectin films also had greater (P < 0.05) tensile strengths than the pure alginate films. Alginate films with extracted cellulose, commercial cellulose, and modified potato starch had lower (P < 0.05) puncture force, distance, and work values than the alginate control films. Transmission electron microscopy images showed a very uniform alginate network in the control films. Several large cellulose fibers were visible in the films with extracted cellulose, while the cellulose fibers in the films with commercial cellulose were difficult to distinguish. Despite these apparent differences in cellulose fiber length, the 2 cellulose films had similar puncture and tensile properties. © 2014 Institute of Food Technologists®

  20. Mechanisms of dynamic wetting failure in the presence of soluble surfactants (United States)

    Kumar, Satish; Liu, Chen-Yu; Carvalho, Marcio S.


    A hydrodynamic model and flow visualization experiments are used to understand the mechanisms through which soluble surfactants can influence the onset of dynamic wetting failure. In the model, a Newtonian liquid displaces air in a rectangular channel in the absence of inertia. A Navier-slip boundary condition and constant contact angle are used to describe the dynamic contact line, and surfactants are allowed to adsorb to the interface and moving channel wall (substrate). The Galerkin finite element method is used to calculate steady states and identify the critical capillary number Cacrit at which wetting failure occurs. It is found that surfactant solubility weakens the influence of Marangoni stresses, which tend to promote the onset of wetting failure. The experiments indicate that Cacrit increases with surfactant concentration. For the more viscous solutions used, this behaviour can largely be explained by accounting for changes to the mean surface tension and static contact angle produced by surfactants. For the lowest-viscosity solution used, comparison between the model predictions and experimental observations suggests that other surfactant-induced phenomena such as Marangoni stresses may play a more important role.

  1. Spatiotemporal characteristics of severe dry and wet conditions in the Free State Province, South Africa (United States)

    Mbiriri, M.; Mukwada, G.; Manatsa, D.


    This paper assesses the spatiotemporal characteristics of agricultural droughts and wet conditions in the Free State Province of South Africa for the period between 1960 and 2013. Since agriculturally, the Free State Province is considered the bread basket of the country, understanding the variability of drought and wet conditions becomes necessary. The Standardised Precipitation Index (SPI) computed from gridded monthly precipitation data was used to assess the rainfall extreme conditions. Hot spot analysis was used to divide the province into five homogenous clusters where the spatiotemporal characteristics for each cluster were analysed. The results show a west to east increase in seasonal average total precipitation. However, the eastern part of the province demonstrates higher occurrences of droughts, with SPI ≤ - 1.282. This is despite the observation that the region shows a recent increase in droughts unlike the western region. It is also noted that significant differences in drought/wet intensities between clusters are more pronounced during the early compared to the late summer period.

  2. Dynamic Temperature Rise Mechanism and Some Controlling Factors of Wet Clutch Engagement

    Directory of Open Access Journals (Sweden)

    Zhang Zhigang


    Full Text Available The friction transmission model of wet clutch is established to analyze the friction transmission mechanism of its engagement. The model is developed by applying both the average flow model and the elastic contact model between the friction disk and separator plate. The key components during wet clutch engagement are the separator plate, friction disk, and lubricant. The one-dimension transient models of heat transfer in radial direction for the three components are built on the basis of the heat transfer theory and the conservation law of energy. The friction transmission model and transient heat transfer models are coupled and solved by using the Runge-Kutta numerical method, and the radial temperature distribution and their detailed parametric study for the three components are conducted separately. The simulation results show that the radial temperature for the three components rises with the increase of radius in engagement. The changes in engagement pressure, lubricant viscosity, friction lining permeability, combined surface roughness RMS, equivalent elasticity modulus, difference between dynamic and static friction coefficients, and lubricant flow have important influence on the temperature rise characteristics. The proposed models can get better understanding of the dynamic temperature rise characteristics of wet clutch engagement.

  3. Understanding physics

    CERN Document Server

    Cassidy, David; Rutherford, James


    Understanding Physics provides a thorough grounding in contemporary physics while placing physics into its social and historical context Based in large part on the highly respected Project Physics Course developed by two of the authors, it also integrates the results of recent pedagogical research The text thus - teaches about the basic phenomena in the physical world and the concepts developed to explain them - shows that science is a rational human endeavor with a long and continuing tradition, involving many different cultures and people - develops facility in critical thinking, reasoned argumentation, evaluation of evidence, mathematical modeling, and ethical values The treatment emphasizes not only what we know but also how we know it, why we believe it, and what effects that knowledge has - Why do we believe the Earth and planets revolve around the Sun? - Why do we believe that matter is made of atoms? - How do relativity theory and quantum mechanics alter our conception of Nature and in what ways do th...

  4. Molecular dynamics of wetting layer formation and forced water invasion in angular nanopores with mixed wettability

    Energy Technology Data Exchange (ETDEWEB)

    Sedghi, Mohammad, E-mail:; Piri, Mohammad; Goual, Lamia [Department of Chemical and Petroleum Engineering, University of Wyoming, 1000 East University Avenue, Laramie, Wyoming 82071 (United States)


    The depletion of conventional hydrocarbon reservoirs has prompted the oil and gas industry to search for unconventional resources such as shale gas/oil reservoirs. In shale rocks, considerable amounts of hydrocarbon reside in nanoscale pore spaces. As a result, understanding the multiphase flow of wetting and non-wetting phases in nanopores is important to improve oil and gas recovery from these formations. This study was designed to investigate the threshold capillary pressure of oil and water displacements in a capillary dominated regime inside nanoscale pores using nonequilibrium molecular dynamics (NEMD) simulations. The pores have the same cross-sectional area and volume but different cross-sectional shapes. Oil and water particles were represented with a coarse grained model and the NEMD simulations were conducted by assigning external pressure on an impermeable piston. Threshold capillary pressures were determined for the drainage process (water replaced by oil) in different pores. The molecular dynamics results are in close agreements with calculations using the Mayer-Stowe-Princen (MS-P) method which has been developed on the premise of energy balance in thermodynamic equilibrium. After the drainage simulations, a change in wall particles’ wettability from water-wet to oil-wet was implemented based on the final configuration of oil and water inside the pore. Waterflooding simulations were then carried out at the threshold capillary pressure. The results show that the oil layer formed between water in the corner and in the center of the pore is not stable and collapses as the simulation continues. This is in line with the predictions from the MS-P method.

  5. Thickness of Residual Wetting Film in Liquid-Liquid Displacement in Capillary Channels (United States)

    Beresnev, I. A.; Gaul, W.; Vigil, D.


    Core-annular flow is common in nature, representing, for example, how streams of oil, surrounded by water, move in petroleum reservoirs. Oil, typically a non-wetting fluid, tends to occupy the middle (core) part of a channel, while water forms a surrounding wall-wetting film. What is the thickness of this wetting film? Understanding this question may determine the ultimate oil recovery. A classic theory has been in existence for nearly 50 years offering a solution, although in a controversial manner, for moving gas bubbles. On the other hand, an acceptable, experimentally verified theory for a body of one liquid flowing in another has not been available. We develop a hydrodynamic, testable theory providing an explicit relationship between the thickness of the wetting film and fluid properties for a blob of one fluid moving in another, with neither phase being gas. In its relationship to the capillary number Ca, the thickness of the film is predicted to be proportional to Ca2 at lower Ca and to level off at a constant value of about 20 % the channel radius at higher Ca. The thickness of the film is deduced to be approximately unaffected by the viscosity ratio of the fluids. We have conducted our own laboratory experiments and compiled experimental data from other studies, all of which are mutually consistent and confirm the salient features of the theory. At the same time, the classic law, originally deduced for films surrounding moving gas bubbles but often believed to hold for liquids as well, fails to explain the observations.

  6. Improved hydrogen sorption kinetics in wet ball milled Mg hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Li


    In this work, wet ball milling method is used in order to improve hydrogen sorption behaviour due to its improved microstructure of solid hydrogen materials. Compared to traditional ball milling method, wet ball milling has benefits on improvement of MgH{sub 2} microstructure and further influences on its hydrogen sorption behavior. With the help of solvent tetrahydrofuran (THF), wet ball milled MgH{sub 2} powder has much smaller particle size and its specific surface area is 7 times as large as that of dry ball milled MgH{sub 2} powder. Although after ball milling the grain size is decreased a lot compared to as-received MgH{sub 2} powder, the grain size of wet ball milled MgH{sub 2} powder is larger than that of dry ball milled MgH{sub 2} powder due to the lubricant effect of solvent THF during wet ball milling. The improved particle size and specific surface area of wet ball milled MgH{sub 2} powder is found to be determining its hydrogen sorption kinetics especially at relatively low temperatures. And it also shows good cycling sorption behavior, which decides on its industrial applicability. With three different catalysts MgH{sub 2} powder shows improved hydrogen sorption behavior as well as the cyclic sorption behavior. Among them, the Nb{sub 2}O{sub 5} catalyst is found to be the most effective one in this work. Compared to the wet ball milled MgH{sub 2} powder, the particle size and specific surface area of the MgH{sub 2} powder with catalysts are similar to the previous ones, while the grain size of the MgH{sub 2} with catalysts is much finer. In this case, two reasons for hydrogen sorption improvement are suggested: one is the reduction of the grain size. The other may be as pointed out in some literatures that formation of new oxidation could enhance the hydrogen sorption kinetics, which is also the reason why its hydrogen capacity is decreased compared to without catalysts. After further ball milling, the specific surface area of wet ball milled Mg

  7. A novel linear physical model for remote sensing of snow wetness and snow density using the visible and infrared bands (United States)

    Varade, D. M.; Dikshit, O.


    Modeling and forecasting of snowmelt runoff are significant for understanding the hydrological processes in the cryosphere which requires timely information regarding snow physical properties such as liquid water content and density of snow in the topmost layer of the snowpack. Both the seasonal runoffs and avalanche forecasting are vastly dependent on the inherent physical characteristics of the snowpack which are conventionally measured by field surveys in difficult terrains at larger impending costs and manpower. With advances in remote sensing technology and the increase in the availability of satellite data, the frequency and extent of these surveys could see a declining trend in future. In this study, we present a novel approach for estimating snow wetness and snow density using visible and infrared bands that are available with most multi-spectral sensors. We define a trapezoidal feature space based on the spectral reflectance in the near infrared band and the Normalized Differenced Snow Index (NDSI), referred to as NIR-NDSI space, where dry snow and wet snow are observed in the left diagonal upper and lower right corners, respectively. The corresponding pixels are extracted by approximating the dry and wet edges which are used to develop a linear physical model to estimate snow wetness. Snow density is then estimated using the modeled snow wetness. Although the proposed approach has used Sentinel-2 data, it can be extended to incorporate data from other multi-spectral sensors. The estimated values for snow wetness and snow density show a high correlation with respect to in-situ measurements. The proposed model opens a new avenue for remote sensing of snow physical properties using multi-spectral data, which were limited in the literature.

  8. Understanding PISA

    Directory of Open Access Journals (Sweden)

    Stephen DOWNES


    Full Text Available Understanding PISA Stephen DOWNESMoncton, CANADA ABSTRACT The headline was dramatic enough to cause a ripple in the reading public. "Students who use computers a lot at school have worse maths and reading performance," noted the BBC news article, citing a 2004 study by Ludger Woessmann and Thomas Fuchs (Fuchs and Woessman, 2004. It was not long before the blogosphere took notice. Taking the theme and running with it, Alice and Bill ask, "Computers Make School Kids Dumber?" They theorize, "If you track the admitted decline of education, you'll probably notice that it follows along with the increase of technology in the classroom." In a similar vein, James Bartholomew asks, "Do you think that the government will turn down the volume of its boasting about how it has spent billions introducing computers in schools (while keeping down the pay of teachers so much that there are shortages? Do you think it will stop sending governors of state schools glossy pamphlets about insisting that computers are used in their schools as much as possible?" In this study, therefore, PISA looks well beyond educational attainment, and also includes school demographics, such as whether it is a public or private school, has large or small classes, or has access or not to technological resources. Finally, it does measure student information-their family background, access to books and computers and parental support as well. The PISA survey departs from previous surveys in disregarding the stated curricula of the schools being measured. Therefore, the conclusion is not surprising, nor even wrong for him to consider independently of any parental or teacher support, considered without reference to the software running on it, considered without reference to student attitudes and interests, does not positively impact an education. Finally, he focus on missing the reporting of results

  9. The Sequence of Wet and Dry Days at Ibadan and Onne (Sub ...

    African Journals Online (AJOL)

    Twenty-three years daily rainfall data were collected for Ibadan while twenty years data were collected for Onne. These data were analysed and modelled for the dependence of wet days following dry days; dry days following wet days; dry days following dry days and wet days following wet days using the first order Markov ...

  10. Examining Wetting and Dewetting Processes in Thin-films on Crystalline Substrates at the Nanoscale (United States)

    Hihath, Sahar

    Controlling the wetting and dewetting of ultra-thin films on solid substrates is important for a variety of technological and fundamental research applications. These applications include film deposition for semiconductor manufacturing, the growth of nanowires through nanoparticle-based catalysis sites, to making ordered arrays of nanoscale particles for electronic and optical devices. However, despite the importance of these processes, the underlying mechanisms by which a film wets a surface or dewets from it is still often unclear and widely debated. In this dissertation we examine wetting and dewetting processes in three materials systems that are relevant for device applications with the ultimate goal of understanding what mechanisms drive the wetting (or dewetting) process in each case. First, we examine the formation of wetting layers between nanoparticle films and highly conductive GaAs substrates for spintronic applications. In this case, the formation of a wetting layer is important for nanoparticle adhesion on the substrate surface. Wetting layers can be made by annealing these systems, which causes elemental diffusion from nanoparticles into the substrate, thereby adhesion between the nanoparticles and the substrate. Here we investigate the feasibility of forming a wetting layer underneath nanoparticles post-annealing in a system of Fe3O4 nanoparticles on a (100) GaAs substrate by studying the interface structure and composition via Transmission Electron Microscopy (TEM), Scanning Transmission Electron Microscopy (STEM), Electron Energy Loss Spectroscopy (EELS) and Energy Dispersive X-ray Spectroscopy (EDXS). Electron Energy-Loss fine structures of the Fe-L 3,2 and O-K absorption edges were quantitatively analyzed to gain insight about the compositional gradient of the interface between the nanoparticles and the GaAs substrate. Additionally, real-space density functional theory calculations of the dynamical form factor was performed to confirm the

  11. Skid resistance determination for pavement management and wet-weather road safety


    T.F. Fwa


    Road accidents during wet weather have been a topic of major concern of road engineers in regions of wet-tropical climate and in other parts of the world during the wet season of the year. Road safety studies indicate that approximately 20% of all road accidents occurred during wet weather, and that the skid resistance of wet pavements have a major influence on the occurrences of wet-weather accidents. Monitoring of wet pavement skid resistance has been an integral part of a typical pavement ...

  12. Liquid Metal Phagocytosis: Intermetallic Wetting Induced Particle Internalization. (United States)

    Tang, Jianbo; Zhao, Xi; Li, Jing; Zhou, Yuan; Liu, Jing


    A biomimetic cellular-eating phenomenon in gallium-based liquid metal to realize particle internalization in full-pH-range solutions is reported. The effect, which is called liquid metal phagocytosis, represents a wet-processing strategy to prepare various metallic liquid metal-particle mixtures through introducing excitations such as an electrical polarization, a dissolving medium, or a sacrificial metal. A nonwetting-to-wetting transition resulting from surface transition and the reactive nature of the intermetallic wetting between the two metallic phases are found to be primarily responsible for such particle-eating behavior. Theoretical study brings forward a physical picture to the problem, together with a generalized interpretation. The model developed here, which uses the macroscopic contact angle between the two metallic phases as a criterion to predict the particle internalization behavior, shows good consistency with experimental results.

  13. Helminths in rodents from Wet Markets in Thailand

    Directory of Open Access Journals (Sweden)

    Ribas A.


    Full Text Available Only a few surveys have ever been carried out of the helminths of the commensal rodents found in the traditional wet markets that play such an important part of daily life in South-east Asia. The potential of rodents as reservoirs of zoonoses including helminths is of great interest since in these markets humans and rodents come into closer contact than in other environments and food may be indirectly contaminated via rodent faeces. Helminths in a total of 98 rats belonging to two species (Rattus norvegicus and Rattus exulans were surveyed in eight traditional wet markets in Udon Thani, Thailand. Thirteen species of helminths were recovered, seven of which are potentially zoo-notic, with an overall prevalence of 89.8 %. Our results show that rodents in wet markets could pose a threat to human health as potential reservoirs of zoonotic helminthiases.

  14. Bio-Inspired Extreme Wetting Surfaces for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Sera Shin


    Full Text Available Biological creatures with unique surface wettability have long served as a source of inspiration for scientists and engineers. More specifically, materials exhibiting extreme wetting properties, such as superhydrophilic and superhydrophobic surfaces, have attracted considerable attention because of their potential use in various applications, such as self-cleaning fabrics, anti-fog windows, anti-corrosive coatings, drag-reduction systems, and efficient water transportation. In particular, the engineering of surface wettability by manipulating chemical properties and structure opens emerging biomedical applications ranging from high-throughput cell culture platforms to biomedical devices. This review describes design and fabrication methods for artificial extreme wetting surfaces. Next, we introduce some of the newer and emerging biomedical applications using extreme wetting surfaces. Current challenges and future prospects of the surfaces for potential biomedical applications are also addressed.

  15. Regulated wet nursing: managed care or organized crime? (United States)

    Obladen, Michael


    Wet nursing was widely practiced from antiquity. For the wealthy, it was a way to overcome the burdens of breastfeeding and increase the number of offspring. For the poor, it was an organized industry ensuring regular payment, and in some parishes the major source of income. The abuse of wet nursing, especially the taking in of several nurslings, prompted legislation which became the basis of public health laws in the second half of the 19th century. The qualifications demanded from a mercenary nurse codified by Soran in the 2nd century CE remained unchanged for 1,700 years. When artificial feeding lost its threat thanks to sewage disposal, improved plumbing, the introduction of rubber teats, cooling facilities and commercial formula, wet nursing declined towards the end of the 19th century. Copyright © 2012 S. Karger AG, Basel.

  16. Some specificities of wetting by cyanobiphenyl liquid crystals

    Energy Technology Data Exchange (ETDEWEB)

    Delabre, U; Richard, C; Cazabat, A M, E-mail: cazabat@lps.ens.f [Laboratoire de Physique Statistique, Ecole Normale Superieure, Universite Pierre et Marie Curie, CNRS, 24 rue Lhomond, 75231 Paris Cedex 05 (France)


    The present paper provides an up to date restatement of the wetting behaviour of the series of cyanobiphenyl liquid crystals (LCs) on usual substrates, i.e. oxidized silicon wafers, water and glycerol, at both the macroscopic and microscopic scale, in the nematic range of temperature. We show that on water the systems are close to a wetting transition, especially 5CB and 7CB. In that case, the wetting behaviour is controlled by the presence of impurities. On a mesoscopic scale, we observe for all our (thin LC film-substrate) systems an identical, complex, but well defined general scenario, not accounted for by the available models. In the last part, we present a study on line tension which results from the specific organization of LCs at the edge of the nematic film. We report preliminary results on two-dimensional film coalescence where this line tension plays a major role.

  17. Wet deposition flux of trace elements to the Adirondack region

    International Nuclear Information System (INIS)

    Huang, X.; Keskin, S.S.; Gullu, G.; Olmez, I.


    Wet deposition samples from two locations in the Adirondack region of New York were analyzed for trace elemental composition by instrumental neutron activation analysis. Annual fluxes of the measured species were determined by precipitation-weighted and linear-regression methods. Despite several episodes of high deposition fluxes, the cumulative areal wet deposition of trace elements increased fairly linearly (r 2 > 0.9) over the two year sampling period at both sites. This implies that short duration sampling programs may be used to estimate long-term fluxes and cumulative wet deposition impacts. Based on the magnitude of their fluxes, the measured species have been divided into four groups: acidic anions, electroneutral balancing cations, and minor and trace elements of anthropogenic origin. (author)

  18. Phycoremediation of Heavy Metals in Wet Market Wastewater (United States)

    Apandi, Najeeha; Saphira Radin Mohamed, Radin Maya; Al-Gheethi, Adel; Latiffi, Atikah; Nor Hidayah Arifin, Siti; Gani, Paran


    The efficiency of phycoremediation using microalgae for removing nutrients and heavy metals from wastewaters has been proved. However, the differences in the composition of wastewaters as well as microalgae species play an important role in the efficient of this process. Therefore, the present study aimed to investigate the effectiveness of Scenedesmus sp. to removal of heavy metals from wet market wastewater. Scenedesmus sp. was inoculated with 106 cells/mL into each wet market wastewater concentration included 10, 25, 50, 75 and 100% and incubated for 18 days. The highest growth rate was recorded in 50% WM with a maximum dry weight of 2006 mg L-1 which subsequently removed 93.06% of Cd, 91.5% of Cr, 92.47% of Fe, 92.40% of Zn. These findings reflected the high potential of Scenedesmus sp. in the treatment of wet market wastewater and production microalgae biomass.

  19. In situ transesterification of highly wet microalgae using hydrochloric acid. (United States)

    Kim, Bora; Im, Hanjin; Lee, Jae W


    This study addresses in situ transesterification of highly wet microalgae with hydrochloric acid (HCl) as a catalyst. In situ transesterification was performed by heating the mixture of wet algal cells, HCl, methanol, and solvent in one pot, resulting in the fatty acid methyl ester (FAME) yield over 90% at 95°C. The effects of reaction variables of temperature, amounts of catalyst, reactant, and solvent, and type of solvents on the yield were investigated. Compared with the catalytic effect of H2SO4, in situ transesterification using HCl has benefits of being less affected by moisture levels that are as high as or above 80%, and requiring less amounts of catalyst and solvent. For an equimolar amount of catalyst, HCl showed 15wt.% higher FAME yield than H2SO4. This in situ transesterification using HCl as a catalyst would help to realize a feasible way to produce biodiesel from wet microalgae. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Drying and wetting of building materials and components

    CERN Document Server


    This book, Drying and Wetting of Building Materials and Components, provides a collection of recent contributions in the field of drying and wetting in porous building materials. The main benefit of the book is that it discusses some of the most important topics related to the drying and wetting processes, namely, innovations and trends in drying science and technology, drying mechanism and theory, equipment, advanced modelling, complex simulation and experimentation. At the same time, these topics will be going to the encounter of a variety of scientific and engineering disciplines. The book is divided in several chapters that intend to be a resume of the current state of knowledge for benefit of professional colleagues.

  1. Bio-Inspired Extreme Wetting Surfaces for Biomedical Applications (United States)

    Shin, Sera; Seo, Jungmok; Han, Heetak; Kang, Subin; Kim, Hyunchul; Lee, Taeyoon


    Biological creatures with unique surface wettability have long served as a source of inspiration for scientists and engineers. More specifically, materials exhibiting extreme wetting properties, such as superhydrophilic and superhydrophobic surfaces, have attracted considerable attention because of their potential use in various applications, such as self-cleaning fabrics, anti-fog windows, anti-corrosive coatings, drag-reduction systems, and efficient water transportation. In particular, the engineering of surface wettability by manipulating chemical properties and structure opens emerging biomedical applications ranging from high-throughput cell culture platforms to biomedical devices. This review describes design and fabrication methods for artificial extreme wetting surfaces. Next, we introduce some of the newer and emerging biomedical applications using extreme wetting surfaces. Current challenges and future prospects of the surfaces for potential biomedical applications are also addressed. PMID:28787916

  2. Sequence stratigraphy on an early wet Mars (United States)

    Barker, Donald C.; Bhattacharya, Janok P.


    The evolution of Mars as a water-bearing body is of considerable interest for the understanding of its early history and evolution. The principles of terrestrial sequence stratigraphy provide a useful conceptual framework to hypothesize about the stratigraphic history of the planets northern plains. We present a model based on the hypothesized presence of an early ocean and the accumulation of lowland sediments eroded from highland terrain during the time of the valley networks and later outflow channels. Ancient, global environmental changes, induced by a progressively cooling climate would have led to a protracted loss of surface and near surface water from low-latitudes and eventual cold-trapping at higher latitudes - resulting in a unique and prolonged, perpetual forced regression within basins and lowland depositional environments. The Messinian Salinity Crisis (MSC) serves as a potential terrestrial analogue of the depositional and environmental consequences relating to the progressive removal of large standing bodies of water. We suggest that the evolution of similar conditions on Mars would have led to the emplacement of diagnostic sequences of deposits and regional scale unconformities, consistent with intermittent resurfacing of the northern plains and the progressive loss of an early ocean by the end of the Hesperian era.

  3. Study of wet blasting of components in nuclear power stations

    International Nuclear Information System (INIS)

    Hall, J.


    This report looks at the method of wet blasting radioactive components in nuclear power stations. The wet blaster uses pearl shaped glass beads with the dimensions of 150-250 μm mixed with water as blasting media. The improved design, providing outer operator's positions with proper radiation protection and more efficient blasting equipment has resulted in a lesser dose taken by the operators. The main reason to decontaminate components in nuclear power plants is to enable service on these components. On components like valves, pump shafts, pipes etc. oxides form and bind radiation. These components are normally situated at some distance from the reactor core and will mainly suffer from radiation from so called activation products. When a component is to be decontaminated it can be decontaminated to a radioactive level where it will be declassified. This report has found levels ranging from 150-1000 Bq/kg allowing declassification of radioactive materials. This difference is found between different countries and different organisations. The report also looks at the levels of waste generated using wet blasting. This is done by tracking the contamination to determine where it collects. It is either collected in the water treatment plant or collected in the blasting media. At Barsebaeck the waste levels, from de-contaminating nearly 800 components in one year, results in a waste volume of about 0,250 m 3 . This waste consists of low and medium level waste and will cost about 3 600 EURO to store. The conclusions of the report are that wet blasting is an indispensable way to treat contaminated components in modern nuclear power plants. The wet blasting equipment can be improved by using a robot enabling the operators to remotely treat components from the outer operator's positions. There they will benefit from better radiation protection thus further reduce their taken dose. The wet blasting equipment could also be used to better control the levels of radioactivity on

  4. Wet-dry cycles impact DOM retention in subsurface soils (United States)

    Olshansky, Yaniv; Root, Robert A.; Chorover, Jon


    Transport and reactivity of carbon in the critical zone are highly controlled by reactions of dissolved organic matter (DOM) with subsurface soils, including adsorption, transformation and exchange. These reactions are dependent on frequent wet-dry cycles common to the unsaturated zone, particularly in semi-arid regions. To test for an effect of wet-dry cycles on DOM interaction and stabilization in subsoils, samples were collected from subsurface (Bw) horizons of an Entisol and an Alfisol from the Catalina-Jemez Critical Zone Observatory and sequentially reacted (four batch steps) with DOM extracted from the corresponding soil litter layers. Between each reaction step, soils either were allowed to air dry (wet-dry treatment) before introduction of the following DOM solution or were maintained under constant wetness (continually wet treatment). Microbial degradation was the dominant mechanism of DOM loss from solution for the Entisol subsoil, which had higher initial organic C content, whereas sorptive retention predominated in the lower C Alfisol subsoil. For a given soil, bulk dissolved organic C losses from solution were similar across treatments. However, a combination of Fourier transform infrared (FTIR) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopic analyses revealed that wet-dry treatments enhanced the interactions between carboxyl functional groups and soil particle surfaces. Scanning transmission X-ray microscopy (STXM) data suggested that cation bridging by Ca2+ was the primary mechanism for carboxyl association with soil surfaces. STXM data also showed that spatial fractionation of adsorbed OM on soil organo-mineral surfaces was diminished relative to what might be inferred from previously published observations pertaining to DOM fractionation on reaction with specimen mineral phases. This study provides direct evidence of the role of wet-dry cycles in affecting sorption reactions of DOM to a complex soil matrix. In the soil

  5. Fluorinated Silsesquioxanes: Structure, Solubility, and Wetting (Briefing charts) (United States)


    Charts 3. DATES COVERED (From - To) July 2015-July 2015 4. TITLE AND SUBTITLE FLUORINATED SILSESQUIOXANES: STRUCTURE, SOLUBILITY, AND WETTING... FLUORINATED SILSESQUIOXANES: STRUCTURE, SOLUBILITY, AND WETTING Joseph Mabry, Andrew Guenthner, Scott Iacono, Raymond Campos, Sean Ramirez, Brian Moore...Si O O Si Si Si Si O O O O Si O Si O O O O O Rf Rf Rf Rf Rf Rf Rf Rf OH-/H2O solvent RfSiX3 n = 0, 3, 5, 7 T8 Fluorinated POSS Synthesis Angew Chem

  6. Overview of Nanoparticle Array Formation by Wet Coating

    International Nuclear Information System (INIS)

    Maenosono, Shinya; Okubo, Tatsuya; Yamaguchi, Yukio


    We give a concise overview of nanoparticle array formation by wet coating techniques including patterned assembly, surface modification of nanoparticles, rheology, assembling dynamics, and function of nanoparticle arrays. For the rapid fabrication of large-area and/or patterned nanoparticle arrays, wet coating techniques, such as spin, dip, spray, gravure, slot, roll, and ink-jet coating, are promising ways for practical use in combination with an evaporation-driven self-assembly technique. We have also referred to the concept of array formation via surface modification

  7. Ranibizumab vs. aflibercept for wet age-related macular degeneration

    DEFF Research Database (Denmark)

    Szabo, Shelagh M; Hedegaard, Morten; Chan, Keith


    the efficacy and safety of reduced frequency dosing for aflibercept, relative to other approved and marketed vascular endothelial growth factor inhibitors for wet AMD, over 12 months. RESEARCH DESIGN AND METHODS: Based on a systematic literature review performed according to a pre-specified protocol......OBJECTIVE: Although a reduced aflibercept (2.0 mg) injection frequency relative to the approved dosing posology is included in national treatment guidelines for wet age-related macular degeneration (AMD), there is limited evidence of its comparative efficacy. The objective was to compare...

  8. Energy and exergy analysis of counter flow wet cooling towers

    Directory of Open Access Journals (Sweden)

    Saravanan Mani


    Full Text Available Cooling tower is an open system direct contact heat exchanger, where it cools water by both convection and evaporation. In this paper, a mathematical model based on heat and mass transfer principle is developed to find the outlet condition of water and air. The model is solved using iterative method. Energy and exergy analysis infers that inlet air wet bulb temperature is found to be the most important parameter than inlet water temperature and also variation in dead state properties does not affect the performance of wet cooling tower. .

  9. Wet-air oxidation cleans up black wastewater

    Energy Technology Data Exchange (ETDEWEB)


    Sterling Organics produces the analgesic paracetamol (acetaminophen) at its Dudley, England, plant. The wastewater from the batch process contains intermediates such as para-aminophenol (PAP) and byproducts such as thiosulfates, sulfites and sulfides. To stay ahead of increasingly strict environmental legislation, Sterling Organics installed a wet-air oxidation system at the Dudley facility in August 1992. The system is made by Zimpro Environmental Inc. (Rothschild, Wis.). Zimpro's wet-air oxidation system finds a way around the limitations of purely chemical or physical processes. In the process, compressed air at elevated temperature and pressure oxidizes the process intermediates and byproducts and removes the color from the wastewater.

  10. Effect of Atmospheric Press on Wet Bulb Depression (United States)

    Wheeler, Raymond M.; Stasiak, Michael A.; Lawson, Jamie; Wehkamp, Cara Ann P.; Dixon, Michael A.


    Our measurements of wet bulb depression at different pressures matched the modeled adiabatic saturation temps reasonably well. At a dry bulb temp of 25 C, the normal wet bulb temp for 30% RH and 100 kPa is approx.15 C, but this dropped to approx.8 C at 10 kPa. The results suggest that psychrometers need direct calibration at the target pressures or that pressure corrected charts are required. For a given vapour pressure deficit, any moist surfaces, including transpiring plant leaves, will be cooler at lower pressures due to the increased evaporation rates.

  11. Topographical Anisotropy and Wetting of Ground Stainless Steel Surfaces

    Directory of Open Access Journals (Sweden)

    Cornelia Bellmann


    Full Text Available Microscopic and physico-chemical methods were used for a comprehensive surface characterization of different mechanically modified stainless steel surfaces. The surfaces were analyzed using high-resolution confocal microscopy, resulting in detailed information about the topographic properties. In addition, static water contact angle measurements were carried out to characterize the surface heterogeneity of the samples. The effect of morphological anisotropy on water contact angle anisotropy was investigated. The correlation between topography and wetting was studied by means of a model of wetting proposed in the present work, that allows quantifying the air volume of the interface water drop-stainless steel surface.

  12. Wetting of doped carbon nanotubes by water droplets

    DEFF Research Database (Denmark)

    Kotsalis, E. M.; Demosthenous, E.; Walther, Jens Honore


    We study the wetting of doped single- and multi-walled carbon nanotubes by water droplets using molecular dynamics simulations. Chemisorbed hydrogen is considered as a model of surface impurities. We study systems with varying densities of surface impurities and we observe increased wetting......, as compared to the pristine nanotube case, attributed to the surface dipole moment that changes the orientation of the interfacial water. We demonstrate that the nature of the impurity is important as here hydrogen induces the formation of an extended hydrogen bond network between the water molecules...

  13. Methane fluxes from a wet puna ecosystem in the Peruvian Andes (United States)

    Jones, Sam; Diem, Torsten; Priscila Huaraca Quispe, Lidia; Quispe Ccahuana, Adan Julian; Meir, Patrick; Arn Teh, Yit


    the seasonal scale with fluxes during the wet season almost an order of magnitude greater than those of the dry season. Mean emissions from bogs during wet and dry season were 85.0 (15.0) and 10.0 (2.0) mg C-CH4 m-2 d-1, respectively. Similarly, mean fluxes in the grassland were 0.4 (0.7) and -0.05 (0.6) mg C-CH4 m-2 d-1. These data highlight the importance of considering such Andean highlands in landscape scale source-sink inventories. In this respect, understanding the influence of differences in climatic regime found across the Andes and determining the areal extent of topographic hotspots driving methane emissions within these environments are key challenges.

  14. Opposing Responses of Bird Functional Diversity to Vegetation Structural Diversity in Wet and Dry Forest. (United States)

    Sitters, Holly; York, Alan; Swan, Matthew; Christie, Fiona; Di Stefano, Julian


    Disturbance regimes are changing worldwide, and the consequences for ecosystem function and resilience are largely unknown. Functional diversity (FD) provides a surrogate measure of ecosystem function by capturing the range, abundance and distribution of trait values in a community. Enhanced understanding of the responses of FD to measures of vegetation structure at landscape scales is needed to guide conservation management. To address this knowledge gap, we used a whole-of-landscape sampling approach to examine relationships between bird FD, vegetation diversity and time since fire. We surveyed birds and measured vegetation at 36 landscape sampling units in dry and wet forest in southeast Australia during 2010 and 2011. Four uncorrelated indices of bird FD (richness, evenness, divergence and dispersion) were derived from six bird traits, and we investigated responses of these indices and species richness to both vertical and horizontal vegetation diversity using linear mixed models. We also considered the extent to which the mean and diversity of time since fire were related to vegetation diversity. Results showed opposing responses of FD to vegetation diversity in dry and wet forest. In dry forest, where fire is frequent, species richness and two FD indices (richness and dispersion) were positively related to vertical vegetation diversity, consistent with theory relating to environmental variation and coexistence. However, in wet forest subject to infrequent fire, the same three response variables were negatively associated with vertical diversity. We suggest that competitive dominance by species results in lower FD as vegetation diversity increases in wet forest. The responses of functional evenness were opposite to those of species richness, functional richness and dispersion in both forest types, highlighting the value of examining multiple FD metrics at management-relevant scales. The mean and diversity of time since fire were uncorrelated with vegetation

  15. Opposing Responses of Bird Functional Diversity to Vegetation Structural Diversity in Wet and Dry Forest.

    Directory of Open Access Journals (Sweden)

    Holly Sitters

    Full Text Available Disturbance regimes are changing worldwide, and the consequences for ecosystem function and resilience are largely unknown. Functional diversity (FD provides a surrogate measure of ecosystem function by capturing the range, abundance and distribution of trait values in a community. Enhanced understanding of the responses of FD to measures of vegetation structure at landscape scales is needed to guide conservation management. To address this knowledge gap, we used a whole-of-landscape sampling approach to examine relationships between bird FD, vegetation diversity and time since fire. We surveyed birds and measured vegetation at 36 landscape sampling units in dry and wet forest in southeast Australia during 2010 and 2011. Four uncorrelated indices of bird FD (richness, evenness, divergence and dispersion were derived from six bird traits, and we investigated responses of these indices and species richness to both vertical and horizontal vegetation diversity using linear mixed models. We also considered the extent to which the mean and diversity of time since fire were related to vegetation diversity. Results showed opposing responses of FD to vegetation diversity in dry and wet forest. In dry forest, where fire is frequent, species richness and two FD indices (richness and dispersion were positively related to vertical vegetation diversity, consistent with theory relating to environmental variation and coexistence. However, in wet forest subject to infrequent fire, the same three response variables were negatively associated with vertical diversity. We suggest that competitive dominance by species results in lower FD as vegetation diversity increases in wet forest. The responses of functional evenness were opposite to those of species richness, functional richness and dispersion in both forest types, highlighting the value of examining multiple FD metrics at management-relevant scales. The mean and diversity of time since fire were uncorrelated

  16. Contribution of fine filler particles to energy dissipation during wet sliding of elastomer compounds on a rough surface

    International Nuclear Information System (INIS)

    Pan Xiaodong


    Elastomer compounds reinforced with precipitated silica can exhibit elevated wet sliding friction on a rough surface in comparison with corresponding compounds filled with carbon black particles. The underlying mechanism is currently not well understood. To unravel this puzzling observation, the variation of wet sliding friction with filler volume fraction is examined at the sliding speed of the order of 1 m s -1 under different lubrication conditions. Depending on the lubrication liquid-water or ethanol-a compound that shows both higher bulk hysteretic loss and lower modulus does not always exhibit a higher wet sliding friction. A thorough characterization of the bulk rheology of the compounds investigated fails to provide the rationale for such behaviour, thus constituting an apparent violation of the conventional viscoelastic understanding of rubber friction on a rough surface. On the other hand, the detected lowering of friction when the lubrication liquid is changed from water to ethanol resembles the effect of liquid medium on interfacial adhesion reported in the literature. Hence, it is suggested that a stronger interfacial attractive interaction should exist in water between the road surface and silica particles on the compound surface immediately next to the road surface. This should be related to the elevated wet sliding friction detected for silica-filled compounds under water lubrication

  17. Wet-etch sequence optimisation incorporating time dependent chemical maintenance

    NARCIS (Netherlands)

    Kruif, B.J. de


    Wafer fabrication is the major cost contributor in semiconductor manufacturing. One of the steps in the fabrication is the removal of exposed layers in an automatic wet-etch station with chemicals. In time, these chemicals get polluted and their effectiveness decreases. Therefore, the chemicals in

  18. Teach Battery Technology with Class-Built Wet Cells (United States)

    Roman, Harry T.


    With some simple metal samples and common household liquids, teachers can build wet cell batteries and use them to teach students about batteries and how they work. In this article, the author offers information that is derived from some simple experiments he conducted in his basement workshop and can easily be applied in the classroom or lab. He…

  19. Aerodynamic force coefficients of plain bridge cables in wet conditions

    DEFF Research Database (Denmark)

    Matteoni, Giulia; Georgakis, Christos T.

    In this paper, the aerodynamic forces and force coefficients from preliminary static wind tunnel tests on a plain cable in wet conditions are presented. The presented results are for several different relative cable wind-angles. A comparison is made with tests in dry conditions. In dry conditions...

  20. Effect of supplementation on reproduction of wet season kidding ...

    African Journals Online (AJOL)

    Seventy-seven mature Tswana goats were used to investigate the effect of supplementation on reproduction of wet season kidding animals. Treatments groups with similar weights were: Unsupplemented Control (UC), Continuous Supplementation (CS), Before Rain Supplementation (BRS) and After Rain Supplementation ...

  1. Dough Rheology and Wet Milling of Hard Waxy Wheat Flours (United States)

    To realize the full potential of waxy wheat (Triticum aestivum L.), wet milling of waxy wheat flour to produce gluten and waxy wheat starch was investigated. Flours of six advanced lines of waxy hard wheats, one normal hard wheat (‘Karl 92’), and one partial waxy wheat (‘Trego’) were fractionated by...

  2. Wetting of water on graphene nanopowders of different thicknesses

    KAUST Repository

    Bera, Bijoyendra


    We study the wetting of graphene nanopowders by measuring the water adsorption in nanopowder flakes of different flake thicknesses. Chemical analysis shows that the graphene flakes, especially the thin ones, might exist in the partially oxidized state. We observe that the thinnest graphene nanopowder flakes do not adsorb water at all, independent of the relative humidity. Thicker flakes, on the other hand, do adsorb an increasing amount of water with increasing humidity. This allows us to assess their wetting behavior which is actually the result of the competition between the adhesive interactions of water and graphene and the cohesive interactions of water. Explicit calculation of these contributions from the van der Waals interactions confirms that the adhesive interactions between very thin flakes of graphene oxide and water are extremely weak, which makes the flakes superhydrophobic. “Liquid marble” tests with graphene nanopowder flakes confirm the superhydrophobicity. This shows that the origin of the much debated “wetting transparency” of graphene is due to the fact that a single graphene or graphene oxide layer does not contribute significantly to the adhesion between a wetting phase and the substrate.

  3. Safety criteria for wet and dry spent fuel storage

    International Nuclear Information System (INIS)

    Vitkova, M.; Gorinov, I.; Dacheva, D.


    An overview of the safety criteria for both type of storage (wet and dry) is presented in this paper. The main criteria - thermal, shielding, radiological - are discussed in details. Some requirement to the materials and the operational regimes are also discussed. An attempt for comparison of the safety criteria and general problems for these both type of storage is made

  4. Deformation of fine-grained synthetic peridotite under wet conditions

    NARCIS (Netherlands)

    McDonnell, R.D.


    Fine-grained hydrated peridotite mylonites have been proposed to play an important role in controlling the strength of the continental lithosphere during rifting. For this reason, the deformation behaviour of wet fine-grained forsterite and forsterite-enstatite materials and the underlying

  5. Macroscopic bulk cohesion and torque for wet granular materials

    NARCIS (Netherlands)

    Roy, Sudeshna; Luding, Stefan; Weinhart, Thomas


    Wet granular materials in steady-state in a quasi-static flow have been studied with discrete particle simulations. The total torque is an experimentally accessible macroscopic quantity that can be used to investigate the shear strength, bulk cohesion and other properties of the materials. We report

  6. Effect of wet feed on cockerel chicken performance | Ogbonna ...

    African Journals Online (AJOL)

    The mean daily feed intake, water consumption, body weight gain and feed conversion efficiency values showed significant differences (P<0.05) between treatments. Considering the ease in producing wet ("moist") feeds, their use in cockerel nutrition offers tremendous commercial benefits if suitable equipment are ...

  7. Wetting characteristics of 3-dimensional nanostructured fractal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Ethan, E-mail: [Nano & Microsystems Research Laboratory, Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, W342 Nebraska Hall, Lincoln, NE 68588-0526 (United States); Liu, Ying; Jiang, Lijia; Lu, Yongfeng [Laser Assisted Nano Engineering Lab, Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, 209N Scott Engineering Center, Lincoln, NE 68588-0511 (United States); Ndao, Sidy, E-mail: [Nano & Microsystems Research Laboratory, Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, W342 Nebraska Hall, Lincoln, NE 68588-0526 (United States)


    Highlights: • Hierarchically structured surfaces were fabricated on the micro/nano-scale. • These structures reduced the contact angle of the inherently hydrophilic material. • Similar surfaces have applications in two-phase heat transfer and microfluidics. - Abstract: This article reports the fabrication and wetting characteristics of 3-dimensional nanostructured fractal surfaces (3DNFS). Three distinct 3DNFS surfaces, namely cubic, Romanesco broccoli, and sphereflake were fabricated using two-photon direct laser writing. Contact angle measurements were performed on the multiscale fractal surfaces to characterize their wetting properties. Average contact angles ranged from 66.8° for the smooth control surface to 0° for one of the fractal surfaces. The change in wetting behavior was attributed to modification of the interfacial surface properties due to the inclusion of 3-dimensional hierarchical fractal nanostructures. However, this behavior does not exactly obey existing surface wetting models in the literature. Potential applications for these types of surfaces in physical and biological sciences are also discussed.

  8. Wet explosion pretreatment of sugarcane bagasse for enhanced enzymatic hydrolysis

    DEFF Research Database (Denmark)

    Biswas, Rajib; Uellendahl, Hinrich; Ahring, Birgitte Kiær


    Wet explosion pretreatment of sugarcane bagasse was investigated in pilot-scale with the aim of obtaining the highest possible sugar yield after pretreatment. The temperatures used were 155, 170, 185 and 200 C with or without addition of oxygen (0.6 MPa pressure). Enzymatic hydrolysis of washed...

  9. A comparative study on isotopic composition of precipitation in wet ...

    Indian Academy of Sciences (India)

    A comparative study on isotopic composition of precipitation in wet tropic and semi-arid stations across southern India. C Unnikrishnan Warrier∗ and M Praveen Babu. Isotope Hydrology Division, Centre for Water Resources Development and Management,. Kunnamangalam P.O., Kozhikode 673 571, Kerala, India. ∗.

  10. Simulations of tropical rainforest albedo: is canopy wetness important?

    Directory of Open Access Journals (Sweden)

    Silvia N.M. Yanagi

    Full Text Available Accurate information on surface albedo is essential for climate modelling, especially for regions such as Amazonia, where the response of the regional atmospheric circulation to the changes on surface albedo is strong. Previous studies have indicated that models are still unable to correctly reproduce details of the seasonal variation of surface albedo. Therefore, it was investigated the role of canopy wetness on the simulated albedo of a tropical rainforest by modifying the IBIS canopy radiation transfer code to incorporate the effects of canopy wetness on the vegetation reflectance. In this study, simulations were run using three versions of the land surface/ecosystem model IBIS: the standard version, the same version recalibrated to fit the data of albedo on tropical rainforests and a modified version that incorporates the effects of canopy wetness on surface albedo, for three sites in the Amazon forest at hourly and monthly scales. The results demonstrated that, at the hourly time scale, the incorporation of canopy wetness on the calculations of radiative transfer substantially improves the simulations results, whereas at the monthly scale these changes do not substantially modify the simulated albedo.

  11. Converting SDAP into gypsum in a wet limestone scrubber

    Energy Technology Data Exchange (ETDEWEB)

    Fogh, F. [Faelleskemikerne, Elsamprojekt A/S, Fredericia (Denmark)


    The ELSAM power pool has an installed electrical capacity of approx. 5 GW{sub e}, mainly firing import coal. The major base load units are equipped with desulphurization units and three different desulphurization technologies are used: the wet limestone gypsum process, the spray dry absorption process and a sulphuric acid process. Gypsum and sulphuric acid are commercialized, whereas it has been difficult to utilize the spray dry absorption product (SDAP). The main constituents of SDAP are calcium sulphide, calcium chloride, hydrated lime and impurities mainly originating from fly ash. Sulphide can be oxidized into sulphate in acidic solution - the reaction is utilized in the wet limestone gypsum process - and the possibility of using any spare capacity in the wet limestone gypsum units to oxidize the sulphide content of SDAP into sulphate and produce usable gypsum has been investigated in the laboratory and in a 400 MW{sub e} equivalent wet limestone unit. The limestone inhibition effect of the addition of SDAP is currently being studied in the laboratory in order to determine the effect of different SDAP types (plant/coal sources) on limestone reactivity before further long-term full-scale tests are performed and permanent use of the process planned. (EG)

  12. Catalytic wet peroxide oxidation of formic acid in wastewater with ...

    African Journals Online (AJOL)


    Jul 3, 2016 ... ABSTRACT. The catalytic wet oxidation of formic acid, using hydrogen peroxide as the oxidizing agent over naturally-occurring iron ore, was explored. Firstly, the decomposition of hydrogen peroxide to its hydroxyl radicals (HO• and HOO•) over naturally-occurring iron ore was investigated. The reaction was ...

  13. Coupling between drainage and coarsening in wet foam

    Indian Academy of Sciences (India)

    Drainage and coarsening are two coupled phenomena during the evolution of wet foam. We show the variation in the growth rate of bubble size, along the height in a column of Gillette shaving foam, by microscope imaging. Simultaneously, the drainage of liquid at the same heights has been investigated by Raman ...

  14. Enhanced wet air oxidation : synergistic rate acceleration upon effluent recirculation (United States)

    Matthew J. Birchmeier; Charles G. Hill; Carl J. Houtman; Rajai H. Atalla; Ira A. Weinstock


    Wet air oxidation (WAO) reactions of cellobiose, phenol, and syringic acid were carried out under mild conditions (155°C; 0.93MPa 02; soluble catalyst, Na5[PV2Mo10O40]). Initial oxidation rates were rapid but decreased to small values as less reactive oxidation products accumulated. Recalcitrant oxidation products were consumed more rapidly, however, if additional...

  15. Drought in an invaded Hawaiian lowland wet forest (United States)

    Jené Michaud; Susan Cordell; T. Colleen Cole; Rebecca Ostertag


    In this study we examined historic drought frequency and hydrologic effects of removing invasive plants from one of the few remaining Hawaiian wet lowland forests, near Hilo, Hawai‘i. We developed a conceptual and statistical model of Hilo droughts using historic rainfall and pan evaporation data and discovered that episodes of low soil moisture were most likely from...

  16. Simulated and measured soil wetting patterns for overlap zone ...

    African Journals Online (AJOL)



    Oct 17, 2011 ... Key words: Drip irrigation, HYDRUS, intersection, soil wetting pattern. INTRODUCTION. Improving water use efficiency is very important for agriculture in arid and semi-arid region. Xinjiang is a typical arid region in China, with water resource only 7.93. × 108 m3, severe evaporation and less rainfall. High.

  17. Characterization of silver nanoparticles prepared by wet chemical ...

    African Journals Online (AJOL)

    produced by wet chemical method exhibited an absorption band at 392.37 nm which is a typical plasmon band, suggesting the formation of silver nanoparticles. The results of dynamic light scattering (DLS) showed non homogeneous. AgNPs with average particle size of 10.31 nm. The appearance of the three peaks in Fig 2.

  18. Adsorption and wetting : experiments, thermodynamics and molecular aspects

    NARCIS (Netherlands)

    Schlangen, L.J.M.


    Adsorption and wetting are related phenomena. In order to improve knowledge of both and their relations, experiments, thermodynamics and a theoretical interpretation have been connected, starring n-alkanes.

    Starting from the Gibbs adsorption equation thermodynamic relations between

  19. Making cassava flour safe using the wetting method

    African Journals Online (AJOL)

    neuropathy in older people, and aggravation of iodine deficiency disorders (such as goitre and cretinism) in iodine deficient areas. The wetting method .... neuropsychological effects in children exposed to high cyanide intake from bitter ... The free poster on page. 24 (back cover) is available in 13 languages - see http://.

  20. Comparison of wet and dry corn stover harvest and storage

    Energy Technology Data Exchange (ETDEWEB)

    Shinners, Kevin J.; Binversie, Benjamin N. [University of Wisconsin, Madison, WI (United States). Department of Biological Systems Engineering; Muck, Richard E.; Weimer, Paul J. [US Dairy Forage Research Center, USDA-ARS, University of Wisconsin (United States)


    Corn stover has great potential as a biomass feedstock, but harvest and storage of this material is challenged by weather conditions at harvest; material moisture; and equipment shortcomings. Field drying characteristics, harvest efficiency and rate, product bulk density, and storage characteristics were quantified for stover harvested and stored in wet or dry form. Only in one case did stover reach dry baling moisture ({proportional_to}20%) in the first 4 d of field drying. Conventional hay and forage harvesting equipment (shredder, rake, forage harvester, round baler, and square baler) produced an average harvested yield of about 30% of the total available stover mass. Harvesting capacity of this equipment was limited by difficulty in gathering shredded stover. The density of chopped or baled stover was less than that typically expected with hay and forage crops. Losses of wet stover ensiled at 44% moisture averaged 3.9% with low levels of fermentation products. Dry stover losses were 3.3% and 18.1% for bales stored indoors and outdoors, respectively. Harvesting wet stover right after grain harvest was timelier and resulted in a greater harvesting rate and yield compared to dry stover harvest. Storing wet stover by ensiling resulted in lower losses and more uniform product moisture compared to dry stover bales stored outdoors. (author)

  1. Microclimate conditions in ventilated wet-walled greenhouses in a ...

    African Journals Online (AJOL)

    Spatial variations of microclimatic conditions in enclosed north–south (N–S) oriented single-arched greenhouse polycarbonate structures, with a wet-wall providing evaporative cooling at the S end, were investigated and displayed online in near real-time. Temperature-controlled fans at the N end extracted air.

  2. Wet faeces produced by sheep fed dried spineless cactus pear ...

    African Journals Online (AJOL)

    Cactus pear cladodes in ruminant diets are characterized by the production of wet faeces and assumed to be diarrhoea. Incremental levels of sun-dried and coarsely ground spineless cactus pear (Opuntia ficus-indica var. Algerian) cladodes were used to substitute part of the lucerne hay in balanced sheep diets. Feed and ...

  3. Locomotion and drag in wet and dry granular media (United States)

    Goldman, Daniel; Kuckuk, Robyn; Sharpe, Sarah


    Many animals move within substrates such as soil and dry sand; the resistive properties of such granular materials (GM) can depend on water content and compaction, but little is known about how such parameters affect locomotion or the relevant physics of drag and penetration. We developed a system to create homogeneous wet GM of varying moisture content and compaction in quantities sufficient to study the burial and subsurface locomotion of the Ocellated skink (C. ocellatus) a desert-generalist lizard. X-ray imaging revealed that in wet and dry GM the lizard slowly buried (~ 30 seconds) propagating a wave from head to tail, while moving in a start-stop motion. During forward movement, the head oscillated, and the forelimb on the convex side of the body propelled the animal. Although body kinematics (and ``slip'') were similar in both substrates, the burial depth was smaller in wet GM. Penetration and drag force experiments on smooth cylinders revealed that wet GM was ~ 3 × more resistive than dry GM, suggesting that during burial the lizard operated near its maximum force producing capability and was thus constrained by environmental properties. work supported by NSF PoLS.

  4. Making cassava flour safe using the wetting method

    Directory of Open Access Journals (Sweden)

    J. Howard Bradbury


    Full Text Available Many people, particularly in Africa, suffer various conditions from eating bitter cassava which contains poisonous cyanogens. As well as poisoning, which sometimes causes death, these conditions include konzo, an irreversible paralysis of the legs, which affects mainly children and young women, impaired neurocognition in children, tropical ataxic neuropathy in older people, and aggravation of iodine deficiency disorders (such as goitre and cretinism in iodine deficient areas. The wetting method removes residual cyanogens, and is an additional method of processing cassava flour after its preparation by one of the traditional methods. The wetting method is simple and easy to use, the traditional thick porridge (fufu or ugali made from the treated flour tastes very good, and the method is readily accepted by rural women in East and Central Africa. Regular use of the wetting method by rural women in 13 villages in the Democratic Republic of Congo has prevented konzo amongst more than 9,000 people. We recommend that the wetting method be used as an additional method to traditional methods to remove cyanogens from cassava flour in tropical Africa.

  5. Wet Season Spatial Occurrence Of Phytoplankton and Zooplankton

    African Journals Online (AJOL)


    ABSTRACT. Investigation into the spatial occurrence of wet season phytoplankton and zooplankton in Lagos lagoon, Nigeria was carried out in October, 2008 in 12 stations. A total of 36 species of phytoplankton from 21 genera, 20 zooplankton species from 17 genera and 10 juvenile forms were recorded for the study.

  6. Robust non-wetting PTFE surfaces by femtosecond laser machining. (United States)

    Liang, Fang; Lehr, Jorge; Danielczak, Lisa; Leask, Richard; Kietzig, Anne-Marie


    Nature shows many examples of surfaces with extraordinary wettability,which can often be associated with particular air-trapping surface patterns. Here,robust non-wetting surfaces have been created by femtosecond laser ablation of polytetrafluoroethylene (PTFE). The laser-created surface structure resembles a forest of entangled fibers, which support structural superhydrophobicity even when the surface chemistry is changed by gold coating. SEM analysis showed that the degree of entanglement of hairs and the depth of the forest pattern correlates positively with accumulated laser fluence and can thus be influenced by altering various laser process parameters. The resulting fibrous surfaces exhibit a tremendous decrease in wettability compared to smooth PTFE surfaces; droplets impacting the virgin or gold coated PTFE forest do not wet the surface but bounce off. Exploratory bioadhesion experiments showed that the surfaces are truly air-trapping and do not support cell adhesion. Therewith, the created surfaces successfully mimic biological surfaces such as insect wings with robust anti-wetting behavior and potential for antiadhesive applications. In addition, the fabrication can be carried out in one process step, and our results clearly show the insensitivity of the resulting non-wetting behavior to variations in the process parameters,both of which make it a strong candidate for industrial applications.

  7. Bianchi Type-I Universe with wet dark fluid

    Indian Academy of Sciences (India)

    In this work, we use wet dark fluid (WDF) as a model for dark energy. This model is in the spirit of the generalized Chaplygin gas (GCG) [9], where a physically motivated equation of state is offered with properties relevant for the dark energy problem. Here the motivation stems from an empirical equation of state proposed.

  8. Robust Non-Wetting PTFE Surfaces by Femtosecond Laser Machining

    Directory of Open Access Journals (Sweden)

    Fang Liang


    Full Text Available Nature shows many examples of surfaces with extraordinary wettability, which can often be associated with particular air-trapping surface patterns. Here, robust non-wetting surfaces have been created by femtosecond laser ablation of polytetrafluoroethylene (PTFE. The laser-created surface structure resembles a forest of entangled fibers, which support structural superhydrophobicity even when the surface chemistry is changed by gold coating. SEM analysis showed that the degree of entanglement of hairs and the depth of the forest pattern correlates positively with accumulated laser fluence and can thus be influenced by altering various laser process parameters. The resulting fibrous surfaces exhibit a tremendous decrease in wettability compared to smooth PTFE surfaces; droplets impacting the virgin or gold coated PTFE forest do not wet the surface but bounce off. Exploratory bioadhesion experiments showed that the surfaces are truly air-trapping and do not support cell adhesion. Therewith, the created surfaces successfully mimic biological surfaces such as insect wings with robust anti-wetting behavior and potential for antiadhesive applications. In addition, the fabrication can be carried out in one process step, and our results clearly show the insensitivity of the resulting non-wetting behavior to variations in the process parameters, both of which make it a strong candidate for industrial applications.

  9. Coupling between drainage and coarsening in wet foam

    Indian Academy of Sciences (India)

    Abstract. Drainage and coarsening are two coupled phenomena during the evolution of wet foam. We show the variation in the growth rate of bubble size, along the height in a column of Gillette shaving foam, by microscope imaging. Simultaneously, the drainage of liquid at the same heights has been investigated by ...

  10. Phase change materials and the perception of wetness. (United States)

    Tiest, Wouter M Bergmann; Kosters, N Dolfine; Kappers, Astrid M L; Daanen, Hein A M


    Phase change materials (PCMs) are increasingly incorporated in textiles in order to serve as a thermal buffer when humans change from a hot to a cold environment and the reverse. Due to the absence of wetness sensors in the skin, cooling of the skin may be perceived as a sensation of wetness instead of cold. In order to investigate if this phenomenon occurs when manipulating textiles, nine subjects were asked to touch or manipulate PCM-treated and untreated fabrics. In 75% of the cases, the subjects indicated that the treated material felt wetter than the untreated material independent of the way the textiles were manipulated. We conclude that incorporating PCMs in textiles may lead to a feeling of wetness which might be uncomfortable. Therefore, we recommend investigating a change in cooling properties to minimise this feeling. This article describes a psychophysical experiment into the sensation of wetness of textiles treated with phase change materials. It was found that in 75% of the cases, subjects found the treated fabric to feel wetter than the untreated. This may affect the comfort of wearing clothes made of these textiles.

  11. Neuropeptide Y inhibits hippocampal seizures and wet dog shakes

    DEFF Research Database (Denmark)

    Woldbye, D P; Madsen, T M; Larsen, P J


    effects in the dentate gyrus and subiculum, but also in areas to which epileptiform EEG activity spreads before reverberating. In addition, NPY strongly reduced seizure-related 'wet dog shakes' (WDS). This is consistent with previous studies showing that the dentate gyrus is essential for the generation...

  12. Catalytic wet peroxide oxidation of formic acid in wastewater with ...

    African Journals Online (AJOL)

    The catalytic wet oxidation of formic acid, using hydrogen peroxide as the oxidizing agent over naturally-occurring iron ore, was explored. Firstly, the decomposition of hydrogen peroxide to its hydroxyl radicals (HO• and HOO•) over naturally-occurring iron ore was investigated. The reaction was monitored by ATR FTIR by ...

  13. Effect of Drug Active Substance Particles on Wet Granulation Process.

    Czech Academy of Sciences Publication Activity Database

    Bělohlav, Z.; Břenková, L.; Hanika, Jiří; Durdil, P.; Rapek, P.; Tomášek, V.


    Roč. 85, A7 (2007) , s. 974-980 ISSN 0263-8762 Institutional research plan: CEZ:AV0Z40720504 Keywords : wet granulation * control * active substance Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 0.837, year: 2007

  14. Effect of Hydrochloric Acid, Mechanical Scarification, Wet Heat ...

    African Journals Online (AJOL)

    Michael Horsfall

    variance showed significant differences between the treatments, the leaves and seedling height performed better than the control(untreated seeds), wet heat, mechanical scarification and 50% hydrochloric acid were found to induce germination of the dormant seeds of Parkia biglobosa These methods could be applied to ...

  15. Effects of sulphuric acid, mechanical scarification and wet heat ...

    African Journals Online (AJOL)

    Effects of different treatment methods on the germination of seeds of Parkia biglobosa (mimosaceae) were carried out. Prior treatment of seeds with sulphuric acid, wet heat and mechanical scarification were found to induce germination of the dormant seeds. These methods could be applied to raise seedlings of the plant for ...

  16. Preparation of tools for lithographically controlled wetting and soft lithography




    Authors: Massmiliano Cavallini, Denis Gentili, Pierpaolo Greco, Francesco Valle & Fabio Biscarini ### Abstract This protocol provides the instructions for designing and fabricating stamping tools with features ranging from nanometer to micrometer scale, including the fabrication using commercial tools such as compact disks or digital video disks. In particular the reported procedures are oriented towards the tools fabrication for lithographically controlled wetting and soft lithograph...

  17. Spatial Variability of Wet Troposphere Delays Over Inland Water Bodies (United States)

    Mehran, Ali; Clark, Elizabeth A.; Lettenmaier, Dennis P.


    Satellite radar altimetry has enabled the study of water levels in large lakes and reservoirs at a global scale. The upcoming Surface Water and Ocean Topography (SWOT) satellite mission (scheduled launch 2020) will simultaneously measure water surface extent and elevation at an unprecedented accuracy and resolution. However, SWOT retrieval accuracy will be affected by a number of factors, including wet tropospheric delay—the delay in the signal's passage through the atmosphere due to atmospheric water content. In past applications, the wet tropospheric delay over large inland water bodies has been corrected using atmospheric moisture profiles based on atmospheric reanalysis data at relatively coarse (tens to hundreds of kilometers) spatial resolution. These products cannot resolve subgrid variations in wet tropospheric delays at the spatial resolutions (of 1 km and finer) that SWOT is intended to resolve. We calculate zenith wet tropospheric delays (ZWDs) and their spatial variability from Weather Research and Forecasting (WRF) numerical weather prediction model simulations at 2.33 km spatial resolution over the southwestern U.S., with attention in particular to Sam Rayburn, Ray Hubbard, and Elephant Butte Reservoirs which have width and length dimensions that are of order or larger than the WRF spatial resolution. We find that spatiotemporal variability of ZWD over the inland reservoirs depends on climatic conditions at the reservoir location, as well as distance from ocean, elevation, and surface area of the reservoir, but that the magnitude of subgrid variability (relative to analysis and reanalysis products) is generally less than 10 mm.

  18. Effects of different feed form (dry and wet) supplemented with ...

    African Journals Online (AJOL)

    This study was conducted to evaluate the effect of different forms of feed presentation (dry and wet) supplemented with Probiotics containing Lactobacillus acidophilus on blood characteristics, microbial load and respiratory rate of growing pigs. Twenty-four crossbreed (Large white x Landrace) pigs with an initial body ...

  19. Enzymatic corn wet milling: engineering process and cost model. (United States)

    Ramírez, Edna C; Johnston, David B; McAloon, Andrew J; Singh, Vijay


    Enzymatic corn wet milling (E-milling) is a process derived from conventional wet milling for the recovery and purification of starch and co-products using proteases to eliminate the need for sulfites and decrease the steeping time. In 2006, the total starch production in USA by conventional wet milling equaled 23 billion kilograms, including modified starches and starches used for sweeteners and ethanol production 1. Process engineering and cost models for an E-milling process have been developed for a processing plant with a capacity of 2.54 million kg of corn per day (100,000 bu/day). These models are based on the previously published models for a traditional wet milling plant with the same capacity. The E-milling process includes grain cleaning, pretreatment, enzymatic treatment, germ separation and recovery, fiber separation and recovery, gluten separation and recovery and starch separation. Information for the development of the conventional models was obtained from a variety of technical sources including commercial wet milling companies, industry experts and equipment suppliers. Additional information for the present models was obtained from our own experience with the development of the E-milling process and trials in the laboratory and at the pilot plant scale. The models were developed using process and cost simulation software (SuperPro Designer) and include processing information such as composition and flow rates of the various process streams, descriptions of the various unit operations and detailed breakdowns of the operating and capital cost of the facility. Based on the information from the model, we can estimate the cost of production per kilogram of starch using the input prices for corn, enzyme and other wet milling co-products. The work presented here describes the E-milling process and compares the process, the operation and costs with the conventional process. The E-milling process was found to be cost competitive with the conventional

  20. Enzymatic corn wet milling: engineering process and cost model

    Directory of Open Access Journals (Sweden)

    McAloon Andrew J


    Full Text Available Abstract Background Enzymatic corn wet milling (E-milling is a process derived from conventional wet milling for the recovery and purification of starch and co-products using proteases to eliminate the need for sulfites and decrease the steeping time. In 2006, the total starch production in USA by conventional wet milling equaled 23 billion kilograms, including modified starches and starches used for sweeteners and ethanol production 1. Process engineering and cost models for an E-milling process have been developed for a processing plant with a capacity of 2.54 million kg of corn per day (100,000 bu/day. These models are based on the previously published models for a traditional wet milling plant with the same capacity. The E-milling process includes grain cleaning, pretreatment, enzymatic treatment, germ separation and recovery, fiber separation and recovery, gluten separation and recovery and starch separation. Information for the development of the conventional models was obtained from a variety of technical sources including commercial wet milling companies, industry experts and equipment suppliers. Additional information for the present models was obtained from our own experience with the development of the E-milling process and trials in the laboratory and at the pilot plant scale. The models were developed using process and cost simulation software (SuperPro Designer® and include processing information such as composition and flow rates of the various process streams, descriptions of the various unit operations and detailed breakdowns of the operating and capital cost of the facility. Results Based on the information from the model, we can estimate the cost of production per kilogram of starch using the input prices for corn, enzyme and other wet milling co-products. The work presented here describes the E-milling process and compares the process, the operation and costs with the conventional process. Conclusion The E-milling process

  1. Biogenic cloud nuclei in the central Amazon during the transition from wet to dry season

    Directory of Open Access Journals (Sweden)

    J. D. Whitehead


    Full Text Available The Amazon basin is a vast continental area in which atmospheric composition is relatively unaffected by anthropogenic aerosol particles. Understanding the properties of the natural biogenic aerosol particles over the Amazon rainforest is key to understanding their influence on regional and global climate. While there have been a number of studies during the wet season, and of biomass burning particles in the dry season, there has been relatively little work on the transition period – the start of the dry season in the absence of biomass burning. As part of the Brazil–UK Network for Investigation of Amazonian Atmospheric Composition and Impacts on Climate (BUNIAACIC project, aerosol measurements, focussing on unpolluted biogenic air masses, were conducted at a remote rainforest site in the central Amazon during the transition from wet to dry season in July 2013. This period marks the start of the dry season but before significant biomass burning occurs in the region. Median particle number concentrations were 266 cm−3, with size distributions dominated by an accumulation mode of 130–150 nm. During periods of low particle counts, a smaller Aitken mode could also be seen around 80 nm. While the concentrations were similar in magnitude to those seen during the wet season, the size distributions suggest an enhancement in the accumulation mode compared to the wet season, but not yet to the extent seen later in the dry season, when significant biomass burning takes place. Submicron nonrefractory aerosol composition, as measured by an aerosol chemical speciation monitor (ACSM, was dominated by organic material (around 81 %. Aerosol hygroscopicity was probed using measurements from a hygroscopicity tandem differential mobility analyser (HTDMA, and a quasi-monodisperse cloud condensation nuclei counter (CCNc. The hygroscopicity parameter, κ, was found to be low, ranging from 0.12 for Aitken-mode particles to 0.18 for accumulation

  2. Efficient solvothermal wet in situ transesterification of Nannochloropsis gaditana for biodiesel production. (United States)

    Kim, Bora; Chang, Yong Keun; Lee, Jae W


    In situ transesterification of wet microalgae is a promising, simplified alternative biodiesel production process that replaces multiple operations of cell drying, extraction, and transesterification reaction. This study addresses enhanced biodiesel production from Nannochloropsis gaditana at elevated temperatures. Compared with the previously reported in situ transesterification process of conducting the reaction at a temperature ranging from 95 to 125 °C, the present work employs higher temperatures of at least 150 °C. This relatively harsh condition allows much less acid catalyst with or without co-solvent to be used during this single extraction-conversion process. Without any co-solvent, 0.58% (v/v) of H 2 SO 4 in the reaction medium can achieve 90 wt% of the total lipid conversion to biodiesel at 170 °C when the moisture content of wet algal paste is 80 wt%. Here, the effects of temperature, acid catalyst, and co-solvent on the FAEE yield and specification were scrutinized, and the reaction kinetic was investigated to understand the solvothermal in situ transesterification reaction at the high temperature. Having a biphasic system (water/chloroform) during the reaction also helped to meet biodiesel quality standard EN 14214, as Na + , K + , Ca 2+ , Mg 2+ cations and phosphorus were detected only below 5 ppm. With highlights on the economic feasibility, wet in situ transesterification at the high temperature can contribute to sustainable production of biodiesel from microalgae by reducing the chemical input and relieve the burden of extensive post purification process, therefore a step towards green process.

  3. Investigation on the effect of seawater to hydraulic property and wetting process of bentonite

    International Nuclear Information System (INIS)

    Hasegawa, Takuma


    On high-level waste disposal, bentonite is one of the most promising material for buffer and backfill material. The hydraulic properties and wetting process of bentonite are important not only for barrier performance assessment but also for prediction of waste disposal environment, such as resaturation time and thermal distribution. In Japan, we should consider the effect of seawater for bentonite, because radioactive waste will be disposed of in coastal area and in marine sediment where seawater remained. However, it is not enough to understand the effect of seawater. Therefore, experimental study was conducted to investigate the effect of seawater on the hydraulic conductivity and wetting process of bentonite. The effect of seawater on hydraulic conductivity is significant for Na-bentonite, the hydraulic conductivity of Na-bentonite in seawater is one order to magnitude higher than that in distilled water. On the other hand, the hydraulic conductivity of Ca-bentonite is not influenced by seawater. The hydraulic conductivity of bentonite decreases as effective montmorillonite density increases. The effective montmorillonite density is ratio between the weight of montmorillonite and volume of porosity and montmorillonite. The hydraulic conductivity of bentonite is close related to swelling property since the hydraulic conductivity decrease as the swelling pressure increase. Wetting process of compacted bentonite could be evaluated by diffusion phenomena since infiltration rate and change of saturation rate and represented by diffusion equation. The effect of seawater on water diffusivity is significant for Na-type bentonite with low effective montmorillonite density. Except for that condition, the water diffusivity of bentonite is almost constant and is not influenced by effective montmorillonite density and seawater. (author)

  4. Two liquids wetting and low hysteresis electrowetting on dielectric applications. (United States)

    Maillard, Mathieu; Legrand, Julien; Berge, Bruno


    This study focuses on electrowetting using two immmiscible liquids on a dielectric coating. It is demonstrated that low contact angle of oil on the hydrophobic surfaces is a key parameter to obtain a low hysteresis system, below 2 degrees . On the basis of these results, three aspects of the wetting properties have been studied: the influence of the surface hydrophobic properties, the design of the liquids according to the hydrophobic surface, and a graphical method to solve the Bartell-Osterhof equation and predict the wetting properties of two liquids on a surface. These results define clear design rules to obtain a low hysteresis system, useful for many applications from liquid lenses to displays and laboratory-on-a-chip.

  5. Analytical modeling of wet compression of gas turbine systems

    International Nuclear Information System (INIS)

    Kim, Kyoung Hoon; Ko, Hyung-Jong; Perez-Blanco, Horacio


    Evaporative gas turbine cycles (EvGT) are of importance to the power generation industry because of the potential of enhanced cycle efficiencies with moderate incremental cost. Humidification of the working fluid to result in evaporative cooling during compression is a key operation in these cycles. Previous simulations of this operation were carried out via numerical integration. The present work is aimed at modeling the wet-compression process with approximate analytical solutions instead. A thermodynamic analysis of the simultaneous heat and mass transfer processes that occur during evaporation is presented. The transient behavior of important variables in wet compression such as droplet diameter, droplet mass, gas and droplet temperature, and evaporation rate is investigated. The effects of system parameters on variables such as droplet evaporation time, compressor outlet temperature and input work are also considered. Results from this work exhibit good agreement with those of previous numerical work.

  6. Non-wetting droplets on hot superhydrophilic surfaces (United States)

    Adera, Solomon; Raj, Rishi; Enright, Ryan; Wang, Evelyn N.


    Controlling wettability by varying surface chemistry and roughness or by applying external stimuli is of interest for a wide range of applications including microfluidics, drag reduction, self-cleaning, water harvesting, anti-corrosion, anti-fogging, anti-icing and thermal management. It has been well known that droplets on textured hydrophilic, that is superhydrophilic, surfaces form thin films with near-zero contact angles. Here we report an unexpected behaviour where non-wetting droplets are formed by slightly heating superhydrophilic microstructured surfaces beyond the saturation temperature (>5 °C). Although such behaviour is generally not expected on superhydrophilic surfaces, an evaporation-induced pressure in the structured region prevents wetting. In particular, the increased thermal conductivity and decreased vapour permeability of the structured region allows this behaviour to be observed at such low temperatures. This phenomenon is distinct from the widely researched Leidenfrost and offers an expanded parametric space for fabricating surfaces with desired temperature-dependent wettability.

  7. Wet Mechanochemical Processing of Celestine using (NH42CO3

    Directory of Open Access Journals (Sweden)

    Deniz Bingöl


    Full Text Available In this study, traditional (univariate method of processing to the wet mechanochemical treatment were applied to obtain both SrCO3 and (NH42SO4 from celestite (SrSO4-(NH42CO3-H2O mixtures in a planetary ball mill. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and chemical analysis were used to analyze products formed during wet milling. A hydrometallurgical process was carried out to examine milling time, ball to grinding material mass ratio, (NH42CO3 to SrSO4 mole ratio and rotational speed of the mill in a planetary mill. Under optimum conditions, a conversion approaching 100% of SrCO3 was obtained.

  8. Reactive wet stamping for patterning of polyelectrolyte multilayers. (United States)

    Cho, Chungyeon; Valverde, Lauralee; Ozin, Geoffrey A; Zacharia, Nicole S


    Patterning of soft films, especially their bulk and not only their surface properties, presents a challenge. Several lithographic techniques do exist, but many of them are complex or limited in their ability to change properties. A few methods of patterning polyelectrolyte multilayers (PEM) have been reported, including microcontact printing and selectively growing layers on patterned self-assembled monolayers, but these all come with certain limitations. We present here the use of a modified microcontact printing method, reactive wet stamping (r-WETs), using a hydrogel stamp soaked in aqueous solutions to create patterns in PEMs. With this technique we are able to locally cause swelling and porosity changes in the PEM films and use our method to qualitatively study the evolution of the porous film morphology. This technique has the potential to locally control chemical functionality, film thickness, and mechanical properties, leading to a new ability to control film architectures both at the film surface and within the bulk of the film.

  9. A big picture prospective for wet waste processing management

    International Nuclear Information System (INIS)

    Gibson, J.D.


    This paper provides an overview of general observations made relative to the technical and economical considerations being evaluated by many commercial nuclear power plants involving their decision making process for implementation of several new wet waste management technologies. The waste management processes reviewed include the use of, Reverse Osmosis, Non-Precoat Filters, Resin Stripping ampersand Recycling, Evaporation ampersand Calcination (RVR trademark, ROVER trademark ampersand Thermax trademark), Compression Dewatering (PressPak trademark), Incineration (Resin Express trademark), Survey ampersand Free Release (Green Is Clean) and Quantum Catalytic Extraction Processing (QCEP trademark). These waste management processes are reviewed relative to their general advantages and disadvantages associated with the processing of various wet waste streams including: reactor make-up water, floor drain sludges and other liquid waste streams such as boric acid concentrates and steam generator cleaning solutions. A summary of the conclusions generally being derived by most utilities associated with the use of these waste management processes is also provided

  10. Comparison of Wet and Dry Grinding in Electromagnetic Mill

    Directory of Open Access Journals (Sweden)

    Szymon Ogonowski


    Full Text Available Comparison of dry and wet grinding process in an electromagnetic mill is presented in this paper. The research was conducted in a batch copper ore grinding. Batch mode allows for precise parametrization and constant repetitive conditions of the experiments. The following key aspects were tested: processing time, feed size, size of the grinding media, mass of the material and graining media, and density of the pulp. The particles size distribution of the product samples was analyzed in the laboratory after each experiment. The paper discusses the experimental results as well as the concept of dry and wet grinding and classification circuits for the electromagnetic mill. The main points of the discussion are the size reduction effectiveness and power consumption of the entire system.

  11. Immobilization of wet solid wastes at nuclear power plants

    International Nuclear Information System (INIS)

    Neilson, R.M. Jr.


    Wet solid wastes are classified into four basic types: spent resins, filter sludges, evaporator concentrates, and miscellaneous liquids. Although the immobilization of wet solid wastes is primarily concerned with the incorporation of the waste with a solidification agent, there are a number of other discrete operations or subsystems involved in the treatment of these wastes that may affect the immobilized waste product. The immobilization process may be broken down into five basic operations: waste collection, waste pretreatment, solidification agent handling, mixing/packaging, and waste package handling. The properties of the waste forms that are ultimately shipped from the reactor site are primarily influenced by the methods utilized during the waste collection, waste pretreatment and mixing/packaging operations. The mixing/packaging (solidification) operation is perhaps the most important stage of the immobilization process. The basic solidification agent types are: absorbants, hydraulic cement, urea-formaldehyde, bitumen, and other polymer systems

  12. Sharing breastmilk: wet nursing, cross feeding, and milk donations. (United States)

    Thorley, Virginia


    Wet nursing and cross feeding both involve the breastfeeding of a child by someone other than the mother. Wet nursing involves a woman who is not the social equal of the employer, is never reciprocal, and is normally for payment. Cross feeding (also 'cross nursing') is the informal sharing of breastfeeding between equals, and is usually unpaid and may be reciprocal. Community attitudes in the late 20th and early 21st centuries are distrustful of this practice, though satisfaction is reported by the women involved in sharing breastfeeding. Community unease has included feelings of revulsion, rationalized by concern about the transmission of infections. Yet recently there have been sporadic feature articles in the print media reporting instances of, and opinions, on these practices. This review article explores the sharing of breastfeeding, principally in Australia, and provides an historical context for concerns about transmission of infection. These issues will also be discussed in relation to human milk banking.

  13. Atmospheric corrosion of copper under wet/dry cyclic conditions

    Energy Technology Data Exchange (ETDEWEB)

    EL-Mahdy, Gamal A. [Department of Metallurgical System Engineering, Yonsei University, 134-Shinchon-dong, Seodaemun-Ku, Seoul, 120-749 (Korea, Republic of)


    The polarization resistance of copper subjected to NaCl and an ammonium sulfate solution under wet/dry cycling conditions was monitored using an EIS impedance technique. The copper samples were exposed to 1 h of immersion using different solutions of pH, temperature and surface orientation and 7 h of drying. The copper plates corroded more substantially on the skyward side than those for a ground ward side. The degree of protection copper oxide provides decrease in an acidic medium (pH 4) more than in a neutral medium (pH 7). The corrosion rate of copper increases rapidly during the initial stages of exposure then decreases slowly and eventually attains the steady state during the last stages of exposure. The corrosion products were analyzed using X-ray diffraction. The corrosion mechanism for copper studied under wet/dry cyclic conditions was found to proceed under the dissolution-precipitation mechanism.

  14. Numerical analysis of wet separation of particles by density differences (United States)

    Markauskas, D.; Kruggel-Emden, H.


    Wet particle separation is widely used in mineral processing and plastic recycling to separate mixtures of particulate materials into further usable fractions due to density differences. This work presents efforts aiming to numerically analyze the wet separation of particles with different densities. In the current study the discrete element method (DEM) is used for the solid phase while the smoothed particle hydrodynamics (SPH) is used for modeling of the liquid phase. The two phases are coupled by the use of a volume averaging technique. In the current study, simulations of spherical particle separation were performed. In these simulations, a set of generated particles with two different densities is dropped into a rectangular container filled with liquid. The results of simulations with two different mixtures of particles demonstrated how separation depends on the densities of particles.

  15. Wetting and free surface flow modeling for potting and encapsulation.

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, Carlton, F.; Brooks, Michael J. (Los Alamos National Laboratory, Los Alamos, NM); Graham, Alan Lyman (Los Alamos National Laboratory, Los Alamos, NM); Noble, David F. (David Frederick) (.; )); Notz, Patrick K.; Hopkins, Matthew Morgan; Castaneda, Jaime N.; Mahoney, Leo James (Kansas City Plant, Kansas City, MO); Baer, Thomas A.; Berchtold, Kathryn (Los Alamos National Laboratory, Los Alamos, NM); Adolf, Douglas Brian; Wilkes, Edward Dean; Rao, Rekha Ranjana; Givler, Richard C.; Sun, Amy Cha-Tien; Cote, Raymond O.; Mondy, Lisa Ann; Grillet, Anne Mary; Kraynik, Andrew Michael


    As part of an effort to reduce costs and improve quality control in encapsulation and potting processes the Technology Initiative Project ''Defect Free Manufacturing and Assembly'' has completed a computational modeling study of flows representative of those seen in these processes. Flow solutions are obtained using a coupled, finite-element-based, numerical method based on the GOMA/ARIA suite of Sandia flow solvers. The evolution of the free surface is solved with an advanced level set algorithm. This approach incorporates novel methods for representing surface tension and wetting forces that affect the evolution of the free surface. In addition, two commercially available codes, ProCAST and MOLDFLOW, are also used on geometries representing encapsulation processes at the Kansas City Plant. Visual observations of the flow in several geometries are recorded in the laboratory and compared to the models. Wetting properties for the materials in these experiments are measured using a unique flowthrough goniometer.

  16. Molecular Structure and Dynamics of Water on Pristine and Strained Phosphorene: Wetting and Diffusion at Nanoscale. (United States)

    Zhang, Wei; Ye, Chao; Hong, Linbi; Yang, Zaixing; Zhou, Ruhong


    Phosphorene, a newly fabricated two-dimensional (2D) nanomaterial, has emerged as a promising material for biomedical applications with great potential. Nonetheless, understanding the wetting and diffusive properties of bio-fluids on phosphorene which are of fundamental importance to these applications remains elusive. In this work, using molecular dynamics (MD) simulations, we investigated the structural and dynamic properties of water on both pristine and strained phosphorene. Our simulations indicate that the diffusion of water molecules on the phosphorene surface is anisotropic, with strain-enhanced diffusion clearly present, which arises from strain-induced smoothing of the energy landscape. The contact angle of water droplet on phosphorene exhibits a non-monotonic variation with the transverse strain. The structure of water on transverse stretched phosphorene is demonstrated to be different from that on longitudinal stretched phosphorene. Moreover, the contact angle of water on strained phosphorene is proportional to the quotient of the longitudinal and transverse diffusion coefficients of the interfacial water. These findings thereby offer helpful insights into the mechanism of the wetting and transport of water at nanoscale, and provide a better foundation for future biomedical applications of phosphorene.

  17. Electrospun Ultrafine Fiber Composites Containing Fumed Silica: From Solution Rheology to Materials with Tunable Wetting. (United States)

    Dufficy, Martin K; Geiger, Mackenzie T; Bonino, Christopher A; Khan, Saad A


    Fumed silica (FS) particles with hydrophobic (R805) or hydrophilic (A150) surface functionalities are incorporated in polyacrylonitrile (PAN) fibers by electrospinning to produce mats with controlled wettability. Rheological measurements are conducted to elucidate the particle-polymer interactions and characterize the system while microscopic and analytic tools are used to examine FS location within both fibers and films to aid in the fundamental understanding of wetting behavior. Unlike traditional polymers, we find these systems to be gel-like, yet electrospinnable; the fumed silica networks break down into smaller aggregates during the electrospinning process and disperse both within and on the surface of the fibers. Composite nanofiber mats containing R805 FS exhibit an apparent contact angle over 130° and remain hydrophobic over 30 min, while similar mats with A150 display rapid surface-wetting with a static contact angle of ∼30°. Wicking experiments reveal that the water absorption properties can be further manipulated, with R805 FS-impregnated mats taking up only 8% water relative to mat weight in 15 min. In contrast, PAN fibers containing A150 FS absorb 425% of water in the same period, even more than the pure PAN fiber (371%). The vastly different responses to water demonstrate the versatility of FS in surface modification, especially for submicron fibrous mats. The role of fumed silica in controlling wettability is discussed in terms of their surface functionality, placement on nanofibers and induced surface roughness.

  18. Transport and transformation of mercury during wet flue gas cleaning process of nonferrous metal smelting. (United States)

    Liu, Zhilou; Wang, Dongli; Peng, Bing; Chai, Liyuan; Liu, Hui; Yang, Shu; Yang, Bentao; Xiang, Kaisong; Liu, Cao


    Reducing mercury emission is hot topic for international society. The first step for controlling mercury in fuel gas is to investigate mercury distribution and during the flue gas treatment process. The mercury transport and transformation in wet flue gas cleaning process of nonferrous smelting industry was studied in the paper with critical important parameters, such as the solution temperature, Hg 0 concentration, SO 2 concentration, and Hg 2+ concentration at the laboratory scale. The mass ratio of the mercury distribution in the solution, flue gas, sludge, and acid fog from the simulated flue gas containing Hg 2+ and Hg 0 was 49.12~65.54, 18.34~35.42, 11.89~14.47, and 1.74~3.54%, respectively. The primary mercury species in the flue gas and acid fog were gaseous Hg 0 and dissolved Hg 2+ . The mercury species in the cleaning solution were dissolved Hg 2+ and colloidal mercury, which accounted for 56.56 and 7.34% of the total mercury, respectively. Various mercury compounds, including Hg 2 Cl 2 , HgS, HgCl 2 , HgSO 4 , and HgO, existed in the sludge. These results for mercury distribution and speciation are highly useful in understanding mercury transport and transformation during the wet flue gas cleaning process. This research is conducive for controlling mercury emissions from nonferrous smelting flue gas and by-products.

  19. Synthesis of ZnO nanopencils using wet chemical method and its investigation as LPG sensor

    Energy Technology Data Exchange (ETDEWEB)

    Shimpi, Navinchandra G., E-mail: [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Jain, Shilpa [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Karmakar, Narayan [Department of Physics, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Shah, Akshara [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Kothari, D.C. [Department of Physics, University of Mumbai, Santacruz (East), Mumbai-400098 (India); National Centre for Nanosciences & Nanotechnology, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Mishra, Satyendra [University Institute of Chemical Technology, North Maharashtra University, Jalgaon (India)


    Highlights: • Synthesis using a simple and cost-effective wet chemical process. • Uniform, monodispersed and pure nanoparticles. • Pencil shaped rods with sharp tips. • Understanding of Growth mechanism. • Efficient LPG sensing with high response. • Morphology dependent sensing. - Abstract: ZnO nanopencils (NPCs) were prepared by a novel wet chemical process, using triethanolamine (TEA) as a mild base, which is relatively simple and cost effective method as compared to hydrothermal method. ZnO NPCs were characterized using powder X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy in mid-IR and far-IR regions, X-ray Photoelectron Spectroscopy (XPS), UV–vis (UV–vis) absorption spectroscopy, room temperature Photoluminescence (PL) spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). ZnO NPCs obtained, were highly pure, uniform and monodispersed.XRD pattern indicated hexagonal unit cell structure with preferred orientation along the c-axis. Sensing behaviour of ZnO NPCs was studied towards Liquefied Petroleum Gas (LPG) at different operating temperatures. The study shows that ZnO NPCs were most sensitive and promising candidate for detection of LPG at 250 °C with gas sensitivity > 60%. The high response towards LPG is due to high surface area of ZnO NPCs and their parallel alignment.

  20. Remarks relating to field experiments to measure the wet scavenging of tracer aerosols

    International Nuclear Information System (INIS)

    Stensland, G.J.


    An important question is whether or not the wet deposition of debris from a single (or multiple) airburst of a nuclear device poses a significant hazard to people on the ground. To answer this question for various scenarios, a basic understanding of the aerosol attachment rates to cloud water and raindrops is needed. The attachment rates can then be incorporated into the cloud physics scavenging models to make intelligent assessments. In order to gain an initial impression as to the importance (order of magnitude) of the wet scavenging effects and to provide the data to validate the cloud scavenging models, tracer release field experiments are useful and necessary. The major purpose of this report is to address questions related to the operation and interpretation of such field tracer efforts and in particular to consider the results from the August 3, 1972, Battelle Northwest Laboratory tracer experiment in St. Louis. The Battelle experiment involved the release of several aerosol tracers at 10,000 to 13,000 feet, near rain clouds, and the measurement of the resulting tracer in the rain collected at the ground level sampling sites

  1. Direct and accurate measurement of size dependent wetting behaviors for sessile water droplets (United States)

    Park, Jimin; Han, Hyung-Seop; Kim, Yu-Chan; Ahn, Jae-Pyeong; Ok, Myoung-Ryul; Lee, Kyung Eun; Lee, Jee-Wook; Cha, Pil-Ryung; Seok, Hyun-Kwang; Jeon, Hojeong


    The size-dependent wettability of sessile water droplets is an important matter in wetting science. Although extensive studies have explored this problem, it has been difficult to obtain empirical data for microscale sessile droplets at a wide range of diameters because of the flaws resulting from evaporation and insufficient imaging resolution. Herein, we present the size-dependent quantitative change of wettability by directly visualizing the three phase interfaces of droplets using a cryogenic-focused ion beam milling and SEM-imaging technique. With the fundamental understanding of the formation pathway, evaporation, freezing, and contact angle hysteresis for sessile droplets, microdroplets with diameters spanning more than three orders of magnitude on various metal substrates were examined. Wetting nature can gradually change from hydrophobic at the hundreds-of-microns scale to super-hydrophobic at the sub-μm scale, and a nonlinear relationship between the cosine of the contact angle and contact line curvature in microscale water droplets was demonstrated. We also showed that the wettability could be further tuned in a size-dependent manner by introducing regular heterogeneities to the substrate. PMID:26657208

  2. Wet-steam erosion of steam turbine disks and shafts

    International Nuclear Information System (INIS)

    Averkina, N. V.; Zheleznyak, I. V.; Kachuriner, Yu. Ya.; Nosovitskii, I. A.; Orlik, V. G.; Shishkin, V. I.


    A study of wet-steam erosion of the disks and the rotor bosses or housings of turbines in thermal and nuclear power plants shows that the rate of wear does not depend on the diagrammed degree of moisture, but is determined by moisture condensing on the surfaces of the diaphragms and steam inlet components. Renovating the diaphragm seals as an assembly with condensate removal provides a manifold reduction in the erosion.

  3. Wetting and Diffusion of Water on Pristine and Strained Phosphorene


    Zhang, Wei; Ye, Chao; Bi, Lin; Yang, Zaixing; Zhou, Ruhong


    Phosphorene, a newly fabricated two-dimensional (2D) nanomaterial, have exhibited promising application prospect in biology. Nonetheless, the wetting and diffusive properties of bio-fluids on phosphorene are still elusive. In this study, using molecular dynamics (MD) simulations, we investigated the structural and dynamic properties of water on pristine and strained phosphorene. The MD simulations illustrated that the diffusion of water molecules on the phosphorene surface is anisotropic, whi...

  4. The Fernald wet records recovery project: A case history

    Energy Technology Data Exchange (ETDEWEB)

    Sterling, H.J.; Devir, B.R.; Hawley, R.A. [Fernald Environmental Restoration Management Corp., Cincinnati, OH (United States); Freesmeyer, M.T. [USDOE Ohio Field Office (United States)


    This paper discusses a project performed to recover wet records discovered in January 1995 at the Fernald Environmental Management Project (FEMP). This paper discusses the emergency and record recovery phases of the project, the technical options considered for records recovery, and special measures which were required due to radiological contamination of the records. Also, the root causes and lessons learned from the incident, and path forward for future records management operations at Fernald, are discussed.

  5. Estimating Wet Bulb Globe Temperature Using Standard Meteorological Measurements

    International Nuclear Information System (INIS)

    Hunter, C.H.


    The heat stress management program at the Department of Energy''s Savannah River Site (SRS) requires implementation of protective controls on outdoor work based on observed values of wet bulb globe temperature (WBGT). To ensure continued compliance with heat stress program requirements, a computer algorithm was developed which calculates an estimate of WBGT using standard meteorological measurements. In addition, scripts were developed to generate a calculation every 15 minutes and post the results to an Intranet web site

  6. Wetting of bituminized ion-exchangers under simulated repository conditions

    International Nuclear Information System (INIS)

    Aalto, H.; Valkiainen, M.


    According to the present plans the spent nuclear fuel from four Finnish nuclear power units will be transferred after interim storage to the final disposal site where it will be encapsulated and disposed of in a final repository constructed into the bedrock at a depth of 500 meters. Low and medium level waste generated at nuclear power plants will be finally disposed of in caverns constructed in the bedrock at the power plant site. The safety of the final disposal is based on a multibarrier concept and the degree of safety is estimated by using predictive models. The properties of the waste form are taken into account in the design of the repository construction. Bitumen has been chosen as an immobilisation agent for the wet wastes at Olkiluoto Power Plant, where two BWR units, TVO 1 and TVO 2, have separate bituminization facilities designed by Asea-Atom. Properties of bituminized spent ion-exchange resins from Olkiluoto power plant have been studied by VTT Chemical Technology since the late 70's. These studies have concentrated mainly on determining the long-term behaviour of the bituminization product under the repository conditions. Current interest lies on wetted product as a diffusion barrier. For this purpose a microscopic method for the visualisation of the structure of the wetted product has been developed. The equilibration of the samples in simulated concrete groundwater is currently going on at a temperature of 5-8 deg. C. Preliminary results are presented in this paper. Diffusion experiments have been planned for the further characterising of the wetted product as a release barrier for radionuclides including modelling. (author)

  7. Deburring die-castings by wet vibratory plant (United States)

    Loeschbart, H. M.


    A wet vibratory procedure for the removal of burrs from die castings is described. In this process synthetic abrasive chips and detergent solutions are agitated with the work in such a way as to produce a spiral circulatory movement. Details of various forms of vibrator basin and shapes of abrasive are illustrated. The automation of deburring is illustrated through the application of vibrators of spiral design in combination with transport and drying devices.

  8. Manganese zinc ferrite nanoparticles as efficient catalysts for wet ...

    Indian Academy of Sciences (India) Keywords. Spinel ferrites; catalytic activity; wet peroxide oxidation; 4-chlorophenol; water treatment. Abstract. Manganese substituted zinc nanoparticles, MnxZn1−xFe2O4 (x = 0.0, 0.25, 0.5, 0.75, 1.0) prepared by sol gel method were found to be efficient catalysts for ...

  9. Capillary Contact Angle in a Completely Wet Groove

    Czech Academy of Sciences Publication Activity Database

    Parry, A.O.; Malijevský, Alexandr; Rascón, C.


    Roč. 113, č. 14 (2014), s. 146101 ISSN 0031-9007 R&D Projects: GA ČR GA13-09914S Grant - others:EPSRC UK(GB) EP/J009636/1; SSF(ES) FIS2010-22047-C05 Institutional support: RVO:67985858 Keywords : phase equilibria * wetting transitions * narrow pores Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 7.512, year: 2014

  10. Double Barreled Wet Colostomy: Initial Experience and Literature Review


    Luis Salgado-Cruz; Eloy Espin-Basany; Francesc Vallribera-Valls; Jose Sanchez-Garcia; Luis Miguel Jimenez-Gomez; Marc Marti-Gallostra; Ana Garza-Maldonado


    Background. Pelvic exenteration and multivisceral resection in colorectal have been described as a curative and palliative intervention. Urinary tract reconstruction in a pelvic exenteration is achieved in most cases with an ileal conduit of Bricker, although different urinary reservoirs have been described. Methods. A retrospective and observational study of six patients who underwent a pelvic exenteration and urinary tract reconstruction with a double barreled wet colostomy (DBWC) was done,...

  11. A comparison of wet and dry season ozone and CO over Brazil using in situ and satellite measurements

    International Nuclear Information System (INIS)

    Watson, C.E.; Fishman, J.; Gregory, G.L.; Sachse, G.W.


    Several field experiments have measured the regional effects of biomass burning. Two such experiments, designed to understand the chemistry of the Amazon rainforest during both the wet season and dry season, were conducted in the Amazon Basin. The first experiment, ABLE-2A (Amazon Boundary Layer Experiment), took place from July to August 1985, the early dry season, when biomass burning was just beginning. The second experiment, ABLE-2B, took place during the wet season, from April to May 1987, when little biomass burning was occurring. Comparing ABLE ozone data with tropospheric ozone concentrations derived from satellite data, using the method described by Fishman et al., shows a strong correlation between the direct measurements and the derived ozone concentrations, as well as a direct correlation of both to biomass burning. This comparison gives credence to the use of space-based platforms to monitor global chemistry and, in this case, the regional effects of biomass burning

  12. 46 CFR 183.210 - Protection from wet and corrosive environments. (United States)


    ... 46 Shipping 7 2010-10-01 2010-10-01 false Protection from wet and corrosive environments. 183.210... (UNDER 100 GROSS TONS) ELECTRICAL INSTALLATION General Requirements § 183.210 Protection from wet and... corrosion-resistant. ...

  13. A Study on Wet and Dry Tensile Properties of Wood pulp/Lyocell Wetlace Nonwovens (United States)

    Zhang, Yinjiang; Deng, Chao; Qu, Benchen; Zhan, Qu; Jin, Xiangyu


    A new biodegradable wood pulp/Lyocell moist wipe had been developed, which made from wetlaid/spunlace(wetlace) technology. The dry and wet tensile curve characteristics were described and the relationship between dry and wet strength in both machine direction (MD) and cross-machine direction (CD) were investigated. The results indicate that the fabricated wetlace materials are composed of the entanglements and cohesions of wood pulp/Lyocell fibres. The modulus and tensile strength of the materials were obviously decreased in wet state, and the tensile curves in the dry and wet state both can be divided into two parts. It is noted that there exists a high linear correlation between the dry and wet strength in MD or CD. Meanwhile, the diminished amplitude of wet strength in CD is larger than that of wet strength in MD and the relationship fluctuation between the wet and dry strength in CD is significantly higher than that in MD.

  14. Spatial variability of leaf wetness duration in different crop canopies (United States)

    Sentelhas, Paulo C.; Gillespie, Terry J.; Batzer, Jean C.; Gleason, Mark L.; Monteiro, José Eduardo B. A.; Pezzopane, José Ricardo M.; Pedro, Mário J.


    The spatial variability of leaf wetness duration (LWD) was evaluated in four different height-structure crop canopies: apple, coffee, maize, and grape. LWD measurements were made using painted flat plate, printed-circuit wetness sensors deployed in different positions above and inside the crops, with inclination angles ranging from 30 to 45°. For apple trees, the sensors were installed in 12 east-west positions: 4 at each of the top (3.3 m), middle (2.1 m), and bottom (1.1 m) levels. For young coffee plants (80 cm tall), four sensors were installed close to the leaves at heights of 20, 40, 60, and 80 cm. For the maize and grape crops, LWD sensors were installed in two positions, one just below the canopy top and another inside the canopy. Adjacent to each experiment, LWD was measured above nearby mowed turfgrass with the same kind of flat plate sensor, deployed at 30 cm and between 30 and 45°. We found average LWD varied by canopy position for apple and maize (Pcoffee plants, average LWD did not differ between the top and inside the canopy. The comparison by geometric mean regression analysis between crop and turfgrass LWD measurements showed that sensors at 30 cm over turfgrass provided quite accurate estimates of LWD at the top of the crops, despite large differences in crop height and structure, but poorer estimates for wetness within leaf canopies.

  15. Lithium wetting of stainless steel for plasma facing components (United States)

    Skinner, C. H.; Capece, A. M.; Roszell, J. P.; Koel, B. E.


    Ensuring continuous wetting of a solid container by the liquid metal is a critical issue in the design of liquid metal plasma facing components foreseen for NSTX-U and FNSF. Ultrathin wetting layers may form on metallic surfaces under ultrahigh vacuum (UHV) conditions if material reservoirs are present from which spreading and wetting can start. The combined scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and ion beam etching capabilities of a Scanning Auger Microprobe (SAM) have been used to study the spreading of lithium films on stainless steel substrates. A small (mm-scale) amount of metallic lithium was applied to a stainless steel surface in an argon glove box and transferred to the SAM. Native impurities on the stainless steel and lithium surfaces were removed by Ar+ ion sputtering. Elemental mapping of Li and Li-O showed that surface diffusion of Li had taken place at room temperature, well below the 181°C Li melting temperature. The influence of temperature and surface oxidation on the rate of Li spreading on stainless steel will be reported. Support was provided through DOE Contract Number DE-AC02-09CH11466.

  16. Performance of a UASB reactor treating coffee wet wastewater

    International Nuclear Information System (INIS)

    Guardia Puebla, Yans; Rodríguez Pérez, Suyén; Janet Jiménez Hernández; Sánchez Girón, Víctor


    The present work shows the results obtained in the anaerobic digestion process of coffee wet wastewater processing. An UASB anaerobic reactor was operated in single-stage in mesophilic temperature controlled conditions (37±1ºC). The effect of both organic loading rate (OLR) and hydraulic retention time (HRT) in the anaerobic digestion of coffee wet wastewater was investigated. The OLR values considered in the single-stage UASB reactor varied in a range of 3,6-4,1 kgCOD m-3 d-1 and the HRT stayed in a range of 21,5-15,5 hours. The evaluation results show that the best performance of UASB reactor in single-stage was obtained at OLR of 3,6 kg COD m-3 d-1 with an average value of total and soluble COD removal of 77,2% and 83,4%, respectively, and average methane concentration in biogas of 61%. The present study suggests that the anaerobic digestion is suitable to treating coffee wet wastewater. (author)

  17. Level Set Approach to Anisotropic Wet Etching of Silicon

    Directory of Open Access Journals (Sweden)

    Branislav Radjenović


    Full Text Available In this paper a methodology for the three dimensional (3D modeling and simulation of the profile evolution during anisotropic wet etching of silicon based on the level set method is presented. Etching rate anisotropy in silicon is modeled taking into account full silicon symmetry properties, by means of the interpolation technique using experimentally obtained values for the etching rates along thirteen principal and high index directions in KOH solutions. The resulting level set equations are solved using an open source implementation of the sparse field method (ITK library, developed in medical image processing community, extended for the case of non-convex Hamiltonians. Simulation results for some interesting initial 3D shapes, as well as some more practical examples illustrating anisotropic etching simulation in the presence of masks (simple square aperture mask, convex corner undercutting and convex corner compensation, formation of suspended structures are shown also. The obtained results show that level set method can be used as an effective tool for wet etching process modeling, and that is a viable alternative to the Cellular Automata method which now prevails in the simulations of the wet etching process.

  18. Mercury removal in utility wet scrubber using a chelating agent (United States)

    Amrhein, Gerald T.


    A method for capturing and reducing the mercury content of an industrial flue gas such as that produced in the combustion of a fossil fuel or solid waste adds a chelating agent, such as ethylenediaminetetraacetic acid (EDTA) or other similar compounds like HEDTA, DTPA and/or NTA, to the flue gas being scrubbed in a wet scrubber used in the industrial process. The chelating agent prevents the reduction of oxidized mercury to elemental mercury, thereby increasing the mercury removal efficiency of the wet scrubber. Exemplary tests on inlet and outlet mercury concentration in an industrial flue gas were performed without and with EDTA addition. Without EDTA, mercury removal totaled 42%. With EDTA, mercury removal increased to 71%. The invention may be readily adapted to known wet scrubber systems and it specifically provides for the removal of unwanted mercury both by supplying S.sup.2- ions to convert Hg.sup.2+ ions into mercuric sulfide (HgS) and by supplying a chelating agent to sequester other ions, including but not limited to Fe.sup.2+ ions, which could otherwise induce the unwanted reduction of Hg.sup.2+ to the form, Hg.sup.0.

  19. An algorithm for the optimal collection of wet waste. (United States)

    Laureri, Federica; Minciardi, Riccardo; Robba, Michela


    This work refers to the development of an approach for planning wet waste (food waste and other) collection at a metropolitan scale. Some specific modeling features distinguish this specific waste collection problem from the other ones. For instance, there may be significant differences as regards the values of the parameters (such as weight and volume) characterizing the various collection points. As it happens for classical waste collection planning, even in the case of wet waste, one has to deal with difficult combinatorial problems, where the determination of an optimal solution may require a very large computational effort, in the case of problem instances having a noticeable dimensionality. For this reason, in this work, a heuristic procedure for the optimal planning of wet waste is developed and applied to problem instances drawn from a real case study. The performances that can be obtained by applying such a procedure are evaluated by a comparison with those obtainable via a general-purpose mathematical programming software package, as well as those obtained by applying very simple decision rules commonly used in practice. The considered case study consists in an area corresponding to the historical center of the Municipality of Genoa. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Rapid biodiesel production using wet microalgae via microwave irradiation

    International Nuclear Information System (INIS)

    Wahidin, Suzana; Idris, Ani; Shaleh, Sitti Raehanah Muhamad


    Highlights: • Lipid was directly extracted from wet microalgae using microwave irradiation. • The microwave irradiation and water bath-assisted solvent extraction are applied. • Cell walls are significantly disrupted under microwave irradiation. • Highly disrupted cell walls led to higher biodiesel yield in microwave irradiation. • Microwave irradiation is a promising direct technique with high biodiesel yields. - Abstract: The major challenges for industrial commercialized biodiesel production from microalgae are the high cost of downstream processing such as dewatering and drying, utilization of large volumes of solvent and laborious extraction processes. In order to address these issues the microwave irradiation method was used to produce biodiesel directly from wet microalgae biomass. This alternative method of biodiesel production from wet microalgae biomass is compared with the conventional water bath-assisted solvent extraction. The microwave irradiation extracted more lipids and high biodiesel conversion was obtained compared to the water bath-assisted extraction method due to the high cell disruption achieved and rapid transesterification. The total content of lipid extracted from microwave irradiation and water bath-assisted extraction were 38.31% and 23.01% respectively. The biodiesel produced using microwave irradiation was higher (86.41%) compared to the conventional method. Thus microwave irradiation is an attractive and promising technology to be used in the extraction and transesterification process for efficient biodiesel production

  1. Random Vibration Testing of Advanced Wet Tantalum Capacitors (United States)

    Teverovsky, Alexander


    Advanced wet tantalum capacitors allow for improved performance of power supply systems along with substantial reduction of size and weight of the systems that is especially beneficial for space electronics. Due to launch-related stresses, acceptance testing of all space systems includes random vibration test (RVT). However, many types of advanced wet tantalum capacitors cannot pass consistently RVT at conditions specified in MIL-PRF-39006, which impedes their use in space projects. This requires a closer look at the existing requirements, modes and mechanisms of failures, specifics of test conditions, and acceptance criteria. In this work, different lots of advanced wet tantalum capacitors from four manufacturers have been tested at step stress random vibration conditions while their currents were monitored before, during, and after the testing. It has been shown that the robustness of the parts and their reliability are mostly due to effective self-healing processes and limited current spiking or minor scintillations caused by RVT do not increase the risk of failures during operation. A simple model for scintillations events has been used to simulate current spiking during RVT and optimize test conditions. The significance of scintillations and possible effects of gas generation have been discussed and test acceptance criteria for limited current spiking have been suggested.

  2. Review of BNFL's operational experience of wet type flasks

    International Nuclear Information System (INIS)

    McWilliam, D.S.


    BNFL International Transport's operational experience includes shipping 6000te of spent fuel from Japan to Sellafield, through its dedicated terminal at Barrow, and to Cogema La Hague. This fuel was shipped under the PNTL (Pacific Nuclear Transport Ltd) banner for which BNFL is responsible. PNTL owned and operated a fleet of 5 ships for Japanese business and a fleet of 80 wet and 58 dry flasks, for the transport of Light Water Reactor (LWR) spent fuel, from both Pressurised Water Reactors (PWR) and Boiling Water Reactors (BWR). ''Wet'' or ''dry'' flask is the common terminology used to distinguish between spent fuel flasks transporting fuel where the fuel is immersed in water, or spent fuel flasks that have been drained of water and dried. This paper concentrates on the wet type of flask utilised to transport fuel to Sellafield, that is the Excellox type (including similar type NTL derivatives). It aims to provide a summary of operational experience during handling at power stations, shipment, unloading at reprocessors and from scheduled maintenance

  3. Calcium phosphate bioceramics prepared from wet chemically precipitated powders

    Directory of Open Access Journals (Sweden)

    Kristine Salma


    Full Text Available In this work calcium phosphates were synthesized by modified wet chemical precipitation route. Contrary to the conventional chemical precipitation route calcium hydroxide was homogenized with planetary mill. Milling calcium oxide and water in planetary ball mill as a first step of synthesis provides a highly dispersed calcium hydroxide suspension. The aim of this work was to study the influence of main processing parameters of wet chemical precipitation synthesis product and to control the morphology, phase and functional group composition and, consequently, thermal stability and microstructure of calcium phosphate bioceramics after thermal treatment. The results showed that it is possible to obtain calcium phosphates with different and reproducible phase compositions after thermal processing (hydroxyapatite [HAp], β-tricalcium phosphate [β-TCP] and HAp/β-TCP by modified wet-chemical precipitation route. The β-TCP phase content in sintered bioceramics samples is found to be highly dependent on the changes in technological parameters and it can be controlled with ending pH, synthesis temperature and thermal treatment. Pure, crystalline and highly thermally stable (up to 1300°C HAp bioceramics with homogenous grainy microstructure, grain size up to 200–250 nm and high open porosity can be successfully obtained by powder synthesized at elevated synthesis temperature of 70°C and stabilizing ending pH at 9.

  4. Thickness of residual wetting film in liquid-liquid displacement (United States)

    Beresnev, Igor; Gaul, William; Vigil, R. Dennis


    Core-annular flow is common in nature, representing, for example, how streams of oil, surrounded by water, move in petroleum reservoirs. Oil, typically a nonwetting fluid, tends to occupy the middle (core) part of a channel, while water forms a surrounding wall-wetting film. What is the thickness of the wetting film? A classic theory has been in existence for nearly 50 years offering a solution, although in a controversial manner, for moving gas bubbles. On the other hand, an acceptable, experimentally verified theory for a body of one liquid flowing in another has not been available. Here we develop a hydrodynamic, testable theory providing an explicit relationship between the thickness of the wetting film and fluid properties for a blob of one fluid moving in another, with neither phase being gas. In its relationship to the capillary number Ca, the thickness of the film is predicted to be proportional to Ca2 at lower Ca and to level off at a constant value of ˜20% the channel radius at higher Ca. The thickness of the film is deduced to be approximately unaffected by the viscosity ratio of the fluids. We have conducted our own laboratory experiments and compiled experimental data from other studies, all of which are mutually consistent and confirm the salient features of the theory. At the same time, the classic law, originally deduced for films surrounding moving gas bubbles but often believed to hold for liquids as well, fails to explain the observations.

  5. Stochastic Rotation Dynamics simulations of wetting multi-phase flows (United States)

    Hiller, Thomas; Sanchez de La Lama, Marta; Brinkmann, Martin


    Multi-color Stochastic Rotation Dynamics (SRDmc) has been introduced by Inoue et al. [1,2] as a particle based simulation method to study the flow of emulsion droplets in non-wetting microchannels. In this work, we extend the multi-color method to also account for different wetting conditions. This is achieved by assigning the color information not only to fluid particles but also to virtual wall particles that are required to enforce proper no-slip boundary conditions. To extend the scope of the original SRDmc algorithm to e.g. immiscible two-phase flow with viscosity contrast we implement an angular momentum conserving scheme (SRD+mc). We perform extensive benchmark simulations to show that a mono-phase SRDmc fluid exhibits bulk properties identical to a standard SRD fluid and that SRDmc fluids are applicable to a wide range of immiscible two-phase flows. To quantify the adhesion of a SRD+mc fluid in contact to the walls we measure the apparent contact angle from sessile droplets in mechanical equilibrium. For a further verification of our wettability implementation we compare the dewetting of a liquid film from a wetting stripe to experimental and numerical studies of interfacial morphologies on chemically structured surfaces.

  6. Environmental management system case study: textile wet processes

    International Nuclear Information System (INIS)

    Nasreldin, A.A.


    Textile industry is one of the oldest industries, it started very early in the ancient ages, its grows and improves gradually at the first and then rapidly to satisfy other different need of the mankind, even for luxury purposes, this development caused damage to environment, then its need the treatment. Textile wet processes used significant quantities of water and various kind of chemicals marketed under the name textile auxiliaries, to enhance the appearance of the fabric, serviceability, and durability. The chemical contamination of textile wet processes can be a health risk for the mill workers, consumers and for the environment as well. A number of schemes have been proposed in different countries to control the textile wet processes to create better environment and protect the ecosystem from further degradation, the developing countries need to apply their designed policies from the beginning. A theoretical study for probability of application of environmental management system in textile industry, to prevent or eliminate textile industry pollution that considered as one of the largest polluters in Sudanese environment, especially after the government (industrial ministry) support and facilitate to textile industry development. Applying environmental management system can appreciably reduce the textile industry pollution as founded from the study.(Author)

  7. Leakage Currents and Gas Generation in Advanced Wet Tantalum Capacitors (United States)

    Teverovsky, Alexander


    Currently, military grade, established reliability wet tantalum capacitors are among the most reliable parts used for space applications. This has been achieved over the years by extensive testing and improvements in design and materials. However, a rapid insertion of new types of advanced, high volumetric efficiency capacitors in space systems without proper testing and analysis of degradation mechanisms might increase risks of failures. The specifics of leakage currents in wet electrolytic capacitors is that the conduction process is associated with electrolysis of electrolyte and gas generation resulting in building up of internal gas pressure in the parts. The risk associated with excessive leakage currents and increased pressure is greater for high value advanced wet tantalum capacitors, but it has not been properly evaluated yet. In this work, in Part I, leakages currents in various types of tantalum capacitors have been analyzed in a wide range of voltages, temperatures, and time under bias. Gas generation and the level of internal pressure have been calculated in Part II for different case sizes and different hermeticity leak rates to assess maximal allowable leakage currents. Effects related to electrolyte penetration to the glass seal area have been studied and the possibility of failures analyzed in Part III. Recommendations for screening and qualification to reduce risks of failures have been suggested.

  8. Wet milling versus co-precipitation in magnetite ferrofluid preparation

    Directory of Open Access Journals (Sweden)

    Almásy László


    Full Text Available Various uses of ferrofluids for technical applications continuously raise the interest in improvement and optimization of preparation methods. This paper deals with preparation of finely granulated magnetite particles coated with oleic acid in hydrocarbon suspensions following either chemical co-precipitation from iron salt precursors or wet milling of micron size magnetite powder with the goal to compare the benefits and disadvantages of each method. Microstructural measurements showed that both methods gave similar magnetite particle size of 10-15 nm. Higher saturation magnetization was achieved for the wet-milled magnetite suspension compared to relatively rapid co-precipitation synthesis. Different efficacies of ferrophase incorporation into kerosene could be related to the different mechanisms of oleic acid bonding to nanoparticle surface. The comparative data show that wet milling represents a practicable alternative to the traditional co-precipitation since despite of longer processing time, chemicals impact on environment can be avoided as well as the remnant water in the final product.

  9. Melt-Crucible Wetting Behavior in Semiconductor Melt Growth Systems (United States)

    Croell, A.; Lantzsch, R.; Kitanov, S.; Salk, N.; Szofran, F. R.; Tegetmeier, A.


    The wetting angles of several semiconductor-substrate combinations that are of practical importance for crystal growth have been measured: Ga-GaSb-Sb on fused quartz; Ge on fused quartz and carbon-based substrates, each with different roughness; Si on fused quartz plates and on plates coated with fused quartz, Si3N4, and BN powders. The Ga-GaSb-Sb system showed no significant dependence of the wetting angle on the composition despite a large composition dependence of the surface tension. For Ge, the effect of the roughness on the angle could initially be seen on both types of substrates, but for the fused quartz substrates an equilibrium value independent of the surface treatment was reached after several hours of contact time. For Si, total wetting was found for Si3N4 powders. A reduction of the angle over time was found for both fused quartz and BN powders, with the BN powder showing the highest angle at 150-120 deg.

  10. Meteorological testing and analysis of sampling equipment for wet deposition

    International Nuclear Information System (INIS)

    Winkler, P.; Jobst, S.; Harder, C.


    11 rain collector types for wet deposition were subjected to a field test. Two of the nine types were identically constructed. The following measured values were analyzed: amount of rainfall, electrical conductivity, pH value, Cl - , NO 3 - , SO 4 = , NH 4 + , Na + , K + , Ca ++ , Mg ++ , Fe, Pb, Cu, Cd. The analysis was restricted to rainfall. In a basic study structural and statistical analyses of precipitations were made in order to find out from which extent of intensity resp. rain volume per rainfall the precipitations are important for wet deposition. Some sensors required intensities of nearly 1 mm/h in order to recognize all rainfalls. In order to reach a better standardization of the measuring technique the funnel geometry should be standardized. The current technique is not suited for correctly registering the deposition which is connected with light and very light rainfall. It was found out in rinsing tests with diluted HNO 3 that considerable amounts of trace metals accumulate at funnel walls and in headers, although the collecting device had been subjected to a thorough acid purification before. For the determination of the wet deposition of the trace metals problems arise if the samples are filtered and the filters are not analyzed. In that case particle-bound metals which are suspended in raindrops will not be registered. After comparing the equipment some of the devices were improved in order to eliminate known sources of contamination. (orig./KW) [de

  11. Roughness, optical, and wetting properties of nanostructured thin films (United States)

    Schröder, Sven; Coriand, Luisa; Duparré, Angela


    Roughness structures are essential for a variety of functional surfaces, for example surfaces with extreme wetting behavior like superhydrophobicity or superhydrophilicity. On the other hand, roughness also gives rise to light scattering, and thus limits the usability of such surfaces for optical applications. Our approach is based on using small-scale intrinsic roughness components of thin film coatings to achieve the desired functional properties while keeping the light scattering at acceptable levels. A comprehensive measurement and analysis methodology for effectively predicting, defining and controlling the structural and wetting properties of stochastically rough superhydrophobic surfaces is presented. Power Spectral Density (PSD) functions determined from atomic force microscopy data are used for thorough roughness analysis as well as to predict the wetting and light scattering properties. Dynamic contact angle analysis is performed by measuring advancing, receding, roll-off, and bounce-off angles. Examples of natural and technical superhydrophobic surfaces like the Lotus leaf and thin film coatings with stochastic nanoroughness are given. These surfaces reveal high advancing contact angles, low contact angle hysteresis, low roll-off angles, and, consequently, the effect of self-cleaning.

  12. The Investigation of the Cavitation Phenomenon in the Laval Nozzle with Full and Partial Surface Wetting

    Directory of Open Access Journals (Sweden)

    Jablonská Jana


    Full Text Available The article deals with the cavitation phenomenon affected by full and partial wetting of the wall. For the numerical computation of flow in the Laval nozzle the Schnerr-Sauer cavitation model was tested and was used for cavitation research of flow within the nozzle considering partial surface wetting. The coefficient of wetting for various materials was determined using experimental, theoretical and numerical methods of fluid flow due to partial surface wetting.

  13. Surfactant controlled switching of water-in-oil wetting behaviour of ...

    Indian Academy of Sciences (India)


    face wettability due to the surfactant diffusion may have implications in oil–water separation, chemical bed reactors and microfluidic devices. Keywords. Wetting control; porous substrate wetting; porous silica film; surfactant mediated wetting; oil–water contact angle. 1. Introduction. Spreading of liquid on a porous solid. 1.

  14. Surfactant controlled switching of water-in-oil wetting behaviour of ...

    Indian Academy of Sciences (India)


    Abstract. Selective permeation of oil and water across a porous medium, as in oil recovery operations, depends on the preferential wetting properties of the porous medium. We show a profound influence of surfactants in wetting of porous media and thus demonstrate a new route for the control of water-in-oil wetting of ...

  15. 40 CFR 425.40 - Applicability; description of the retan-wet finish-sides subcategory. (United States)


    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Applicability; description of the retan-wet finish-sides subcategory. 425.40 Section 425.40 Protection of Environment ENVIRONMENTAL... CATEGORY Retan-Wet Finish-Sides Subcategory § 425.40 Applicability; description of the retan-wet finish...

  16. Effects of wet-pressing-induced fiber hornification on enzymatic saccharification of lignocelluloses (United States)

    X.L. Luo; Junyong Zhu; Roland Gleisner; H.Y. Zhan


    This article reports the effect of wet-pressing-induced fiber hornification on enzymatic saccharification of lignocelluloses. A wet cellulosic substrate of bleached kraft eucalyptus pulp and two wet sulfite-pretreated lignocellulosic substrates of aspen and lodgepole pine were pressed to various moisture (solids) contents by variation of pressing pressure and pressing...

  17. Elimination and accumulation of polycyclic aromatic hydrocarbons (PAHs) in urban stormwater wet detention ponds

    DEFF Research Database (Denmark)

    Istenič, Daria; Arias, Carlos Alberto; Matamoros, Victor


    The concentrations of polycyclic aromatic hydrocarbons (PAHs) in water and sediments of seven wet detention ponds receiving urban stormwater were investigated. The ponds comprised traditional wet detention ponds with a permanent wet volume and a storage volume as well as ponds that were expanded...

  18. 40 CFR 428.80 - Applicability; description of the wet digestion reclaimed rubber subcategory. (United States)


    ... digestion reclaimed rubber subcategory. 428.80 Section 428.80 Protection of Environment ENVIRONMENTAL... Wet Digestion Reclaimed Rubber Subcategory § 428.80 Applicability; description of the wet digestion... discharges resulting from the production of reclaimed rubber by use of the wet digestion process. ...

  19. [Syphilis, brothels, unwanted children and wet nurses. Italy and syphilis infection in the 19th century]. (United States)

    Sabbatani, S


    In 1861 in Italy a repressive law was passed against prostitution to reduce syphilis transmission. After the constitution of the Kingdom of Italy there began a debate on this law which was harsh on prostitutes and failed to resolve the health problem in question. In 1880, in Italy, studies were promoted under the aegis of a royal commission to understand the social situation of prostitution and the epidemic spread of syphilis. In 1888 Crispi issued new regulations concerning prostitution, prevention and therapy of infectious diseases: three years later a new regulation was established which partly restored the 1861 law. In this paper we present not only the question of prostitution in Italy in relation to syphilis, but also the serious problem of infection transmission to unweaned babies and to wet nurses in orphanages.

  20. Foam-film-stabilized liquid bridge networks in evaporative lithography and wet granular matter

    KAUST Repository

    Vakarelski, Ivan Uriev


    Evaporative lithography using latex particle templates is a novel approach for the self-assembly of suspension-dispersed nanoparticles into ordered microwire networks. The phenomenon that drives the self-assembly process is the propagation of a network of interconnected liquid bridges between the template particles and the underlying substrate. With the aid of video microscopy, we demonstrate that these liquid bridges are in fact the border zone between the underlying substrate and foam films vertical to the substrate, which are formed during the evaporation of the liquid from the suspension. The stability of the foam films and thus the liquid bridge network stability are due to the presence of a small amount of surfactant in the evaporating solution. We show that the same type of foam-film-stabilized liquid bridge network can also propagate in 3D clusters of spherical particles, which has important implications for the understanding of wet granular matter. © 2013 American Chemical Society.

  1. Wetting kinetics of water nano-droplet containing non-surfactant nanoparticles: A molecular dynamics study

    International Nuclear Information System (INIS)

    Lu, Gui; Hu, Han; Sun, Ying; Duan, Yuanyuan


    In this Letter, dynamic wetting of water nano-droplets containing non-surfactant gold nanoparticles on a gold substrate is examined via molecular dynamics simulations. The results show that the addition of non-surfactant nanoparticles hinders the nano-second droplet wetting process, attributed to the increases in both surface tension of the nanofluid and friction between nanofluid and substrate. The droplet wetting kinetics decreases with increasing nanoparticle loading and water-particle interaction energy. The observed wetting suppression and the absence of nanoparticle ordering near the contact line of nano-sized droplets differ from the wetting behaviors reported from nanofluid droplets of micron size or larger

  2. Shape understanding system machine understanding and human understanding

    CERN Document Server

    Les, Zbigniew


    This is the third book presenting selected results of research on the further development of the shape understanding system (SUS) carried out by authors in the newly founded Queen Jadwiga Research Institute of Understanding. In this book the new term Machine Understanding is introduced referring to a new area of research aiming to investigate the possibility of building machines with the ability to understand. It is presented that SUS needs to some extent mimic human understanding and for this reason machines are evaluated according to the rules applied for the evaluation of human understanding. The book shows how to formulate problems and how it can be tested if the machine is able to solve these problems.    

  3. The effect of wet-dry weathering on the rate of bedrock river channel erosion by saltating gravel (United States)

    Inoue, Takuya; Yamaguchi, Satomi; Nelson, Jonathan M.


    Previous work has shown that the bedrock erosion rate E because of collisions of saltating bedload can be expressed by E = βqb(1-Pc), where qb is the sediment transport rate, Pc is the extent of alluvial cover, and β is the abrasion coefficient. However, the dependence of the abrasion coefficient on the physical characteristics of the bedrock material is poorly known, and in particular, the effects of wet-dry weathering on the saltation-abrasion bedrock incision has not been specifically characterized. Observation suggests that the typical wet-dry cycling of exposed bedrock in river beds gives rise to cracks and voids that are likely to alter the incision rate of the material when subjected to impacts of moving sediment. In this study, flume experiments are performed to develop an understanding of how wet-dry cycling affects the rock tensile strength and the bedrock erosion rate. To represent the physical effects of weathering, boring cores taken from natural bedrock channel are exposed to artificial wet-dry cycles. The experimental results suggest the following: (1) the abrasion coefficient for fresh bedrock is estimated by β = 1.0 × 10− 4σT− 2(d/ksb)0.5, where σT is the tensile strength, d is the diameter of colliding gravel, and ksb is the hydraulic roughness height of bedrock; (2) the tensile strength of the bedrock decreases exponentially as a result of repeated wet-dry cycles, σT/σT0 = exp (-CTNWa0/σT0), where σT0 is the initial tensile strength, Wa0 is the initial normalized rate of water absorption., N is the number of wet-dry cycles, and CT is a constant; (3) the erosion rate of fresh bedrock depends on the inverse of the square of tensile strength, but the erosion rate of weathered bedrock depends on the − 1.5 power of tensile strength.

  4. Thermogenic Wet Gas in Immature Caprock Sections: Leakage or Generation. (United States)

    Abrakasa, Selegha; Beka, Francis; Ndukauba, Egesi


    Gas geochemistry, an aspect of Petroleum Geoscience is a growing science, various concepts has been used to evaluation potential source rock for shale gas while in conventional petroleum exploration similar concepts have been used to determine potential productive formation for liquid hydrocarbons. Prior to the present times, headspace gas data had been used to recognize by pass pays, serve as indicators of petroleum accumulations, evaluate maturity and productive capacity of corresponding formations, evaluate the maturity and source of gas accumulations. Integrating studies in bid to achieve high degree of accuracy, data on direct hydrocarbon indicators (DHIs) such as oil stains, oil shows and seeps have been employed. Currently popular among professionals is the use of gas clouds on seismic cross sections. In contemporary times, advancement in gas geochemistry has witnessed the application of concepts on headspace gas to expound the efficiency of petroleum caprocks whose major role is to foster accumulation and preservation. This enables extricating potential leakage mechanism via caprock reservoir interface and unravel its corresponding migrational pathways. In this study thermogenic wet gas has been used as a dependable tool for delineating caprock leakage by discriminating migrant from indigenous hydrocarbons in caprock rock sections overlying the reservoirs. The thermogenic gas profile in corroboration with the thermogenic signature and maturity data were used. Summary statistics indicates that 60% of the 50 wells studied has wet gas up to 500m above the reservoir-caprock interface and 10% of the leaking wells are fracture prone leakage.The amount of wet gas ranges of up to 200,000 ppm in the caprock sections, this indicates pervasive leakage. Log view plots were modelled using Schlumbergers' Techlog, while descriptive lithologies were modeled using Zetawares' genesis.

  5. Dust emission from wet, low-emission coke quenching process (United States)

    Komosiński, Bogusław; Bobik, Bartłomiej; Konieczny, Tomasz; Cieślik, Ewelina


    Coke plants, which produce various types of coke (metallurgical, foundry or heating), at temperatures between 600 and 1200°C, with limited access to oxygen, are major emitters of particulates and gaseous pollutants to air, water and soils. Primarily, the process of wet quenching should be mentioned, as one of the most cumbersome. Atmospheric pollutants include particulates, tar substances, organic pollutants including B(a)P and many others. Pollutants are also formed from the decomposition of water used to quench coke (CO, phenol, HCN, H2S, NH3, cresol) and decomposition of hot coke in the first phase of quenching (CO, H2S, SO2) [1]. The development of the coke oven technology has resulted in the changes made to different types of technological installations, such as the use of baffles in quench towers, the removal of nitrogen oxides by selective NOx reduction, and the introduction of fabric filters for particulates removal. The BAT conclusions for coke plants [2] provide a methodology for the measurement of particulate emission from a wet, low-emission technology using Mohrhauer probes. The conclusions define the emission level for wet quenching process as 25 g/Mgcoke. The conducted research was aimed at verification of the presented method. For two of three quench towers (A and C) the requirements included in the BAT conclusions are not met and emissions amount to 87.34 and 61.35 g/Mgcoke respectively. The lowest particulates emission was recorded on the quench tower B and amounted to 22.5 g/Mgcoke, therefore not exceeding the requirements.

  6. Designing Yellow Intervals for Rainy and Wet Roadway Conditions

    Directory of Open Access Journals (Sweden)

    Huan Li


    Full Text Available The research presented in this paper quantifies and models the impact of wet pavement surface and rainy weather conditions on driver perception-reaction times (PRTs, deceleration levels, and traffic signal change interval durations. A total of 648 stop-run records were collected as part of the research effort for a 72 km/h (45 mi/h approach speed where participant drivers encountered a yellow indication initiation at different distances from the intersection. The participant drivers were randomly selected in different age groups (under 40 years old, 40 to 59 years old, and 60 years of age or older and genders (female and male. Using the gathered data, statistical models for driver PRT and deceleration levels were developed, considering roadway surface and environmental parameters, driver attributes (age and gender, roadway grade, approaching speed, and time and distance to the intersection at the onset of yellow. Inclement weather yellow timings were then developed and summarized in lookup tables as a function of different factors (driver age/gender, roadway grade, speed limit, precipitation level, and roadway surface condition to provide practical guidelines for the design of yellow signal timings in wet and rainy weather conditions. The results indicate that wet roadway surface conditions require a 5 percent increase in the change interval and that rainy conditions require a 10 percent or more increase in the duration of the change interval. These recommended change durations can also be integrated within the Vehicle Infrastructure Integration (VII initiative to provide customizable driver warnings prior to a transition to a red indication.

  7. Dust emission from wet, low-emission coke quenching process

    Directory of Open Access Journals (Sweden)

    Komosiński Bogusław


    Full Text Available Coke plants, which produce various types of coke (metallurgical, foundry or heating, at temperatures between 600 and 1200°C, with limited access to oxygen, are major emitters of particulates and gaseous pollutants to air, water and soils. Primarily, the process of wet quenching should be mentioned, as one of the most cumbersome. Atmospheric pollutants include particulates, tar substances, organic pollutants including B(aP and many others. Pollutants are also formed from the decomposition of water used to quench coke (CO, phenol, HCN, H2S, NH3, cresol and decomposition of hot coke in the first phase of quenching (CO, H2S, SO2 [1]. The development of the coke oven technology has resulted in the changes made to different types of technological installations, such as the use of baffles in quench towers, the removal of nitrogen oxides by selective NOx reduction, and the introduction of fabric filters for particulates removal. The BAT conclusions for coke plants [2] provide a methodology for the measurement of particulate emission from a wet, low-emission technology using Mohrhauer probes. The conclusions define the emission level for wet quenching process as 25 g/Mgcoke. The conducted research was aimed at verification of the presented method. For two of three quench towers (A and C the requirements included in the BAT conclusions are not met and emissions amount to 87.34 and 61.35 g/Mgcoke respectively. The lowest particulates emission was recorded on the quench tower B and amounted to 22.5 g/Mgcoke, therefore not exceeding the requirements.

  8. Adhesive interactions of geckos with wet and dry fluoropolymer substrates. (United States)

    Stark, Alyssa Y; Dryden, Daniel M; Olderman, Jeffrey; Peterson, Kelly A; Niewiarowski, Peter H; French, Roger H; Dhinojwala, Ali


    Fluorinated substrates like Teflon® (poly(tetrafluoroethylene); PTFE) are well known for their role in creating non-stick surfaces. We showed previously that even geckos, which can stick to most surfaces under a wide variety of conditions, slip on PTFE. Surprisingly, however, geckos can stick reasonably well to PTFE if it is wet. In an effort to explain this effect, we have turned our attention to the role of substrate surface energy and roughness when shear adhesion occurs in media other than air. In this study, we removed the roughness component inherent to commercially available PTFE and tested geckos on relatively smooth wet and dry fluoropolymer substrates. We found that roughness had very little effect on shear adhesion in air or in water and that the level of fluorination was most important for shear adhesion, particularly in air. Surface energy calculations of the two fluorinated substrates and one control substrate using the Tabor-Winterton approximation and the Young-Dupré equation were used to determine the interfacial energy of the substrates. Using these interfacial energies we estimated the ratio of wet and dry normal adhesion for geckos clinging to the three substrates. Consistent with the results for rough PTFE, our predictions show a qualitative trend in shear adhesion based on fluorination, and the quantitative experimental differences highlight the unusually low shear adhesion of geckos on dry smooth fluorinated substrates, which is not captured by surface energy calculations. Our work has implications for bioinspired design of synthetics that can preferentially stick in water but not in air.

  9. An Evaluation of Portable Wet Bulb Globe Temperature Monitor Accuracy. (United States)

    Cooper, Earl; Grundstein, Andrew; Rosen, Adam; Miles, Jessica; Ko, Jupil; Curry, Patrick


    Wet bulb globe temperature (WBGT) is the gold standard for assessing environmental heat stress during physical activity. Many manufacturers of commercially available instruments fail to report WBGT accuracy.   To determine the accuracy of several commercially available WBGT monitors compared with a standardized reference device.   Observational study.   Field test.   Six commercially available WBGT devices.   Data were recorded for 3 sessions (1 in the morning and 2 in the afternoon) at 2-minute intervals for at least 2 hours. Mean absolute error (MAE), root mean square error (RMSE), mean bias error (MBE), and the Pearson correlation coefficient ( r) were calculated to determine instrument performance compared with the reference unit.   The QUESTemp° 34 (MAE = 0.24°C, RMSE = 0.44°C, MBE = -0.64%) and Extech HT30 Heat Stress Wet Bulb Globe Temperature Meter (Extech; MAE = 0.61°C, RMSE = 0.79°C, MBE = 0.44%) demonstrated the least error in relation to the reference standard, whereas the General WBGT8778 Heat Index Checker (General; MAE = 1.18°C, RMSE = 1.34°C, MBE = 4.25%) performed the poorest. The QUESTemp° 34 and Kestrel 4400 Heat Stress Tracker units provided conservative measurements that slightly overestimated the WBGT provided by the reference unit. Finally, instruments using the psychrometric wet bulb temperature (General, REED Heat Index WBGT Meter, and WBGT-103 Heat Stroke Checker) tended to underestimate the WBGT, and the resulting values more frequently fell into WBGT-based activity categories with fewer restrictions as defined by the American College of Sports Medicine.   The QUESTemp° 34, followed by the Extech, had the smallest error compared with the reference unit. Moreover, the QUESTemp° 34, Extech, and Kestrel units appeared to offer conservative yet accurate assessments of the WBGT, potentially minimizing the risk of allowing physical activity to continue in stressful heat environments. Instruments using the

  10. Universality in dynamic wetting dominated by contact-line friction. (United States)

    Carlson, Andreas; Bellani, Gabriele; Amberg, Gustav


    We report experiments on the rapid contact-line motion present in the early stages of capillary-driven spreading of drops on dry solid substrates. The spreading data fail to follow a conventional viscous or inertial scaling. By integrating experiments and simulations, we quantify a contact-line friction μ(f) which is seen to limit the speed of the rapid dynamic wetting. A scaling based on this contact-line friction is shown to yield a universal curve for the evolution of the contact-line radius as a function of time, for a range of fluid viscosities, drop sizes, and surface wettabilities.

  11. Wet scrubbing of biomass producer gas tars using vegetable oil (United States)

    Bhoi, Prakashbhai Ramabhai

    The overall aims of this research study were to generate novel design data and to develop an equilibrium stage-based thermodynamic model of a vegetable oil based wet scrubbing system for the removal of model tar compounds (benzene, toluene and ethylbenzene) found in biomass producer gas. The specific objectives were to design, fabricate and evaluate a vegetable oil based wet scrubbing system and to optimize the design and operating variables; i.e., packed bed height, vegetable oil type, solvent temperature, and solvent flow rate. The experimental wet packed bed scrubbing system includes a liquid distributor specifically designed to distribute a high viscous vegetable oil uniformly and a mixing section, which was designed to generate a desired concentration of tar compounds in a simulated air stream. A method and calibration protocol of gas chromatography/mass spectroscopy was developed to quantify tar compounds. Experimental data were analyzed statistically using analysis of variance (ANOVA) procedure. Statistical analysis showed that both soybean and canola oils are potential solvents, providing comparable removal efficiency of tar compounds. The experimental height equivalent to a theoretical plate (HETP) was determined as 0.11 m for vegetable oil based scrubbing system. Packed bed height and solvent temperature had highly significant effect (p0.05) effect on the removal of model tar compounds. The packing specific constants, Ch and CP,0, for the Billet and Schultes pressure drop correlation were determined as 2.52 and 2.93, respectively. The equilibrium stage based thermodynamic model predicted the removal efficiency of model tar compounds in the range of 1-6%, 1-4% and 1-2% of experimental data for benzene, toluene and ethylbenzene, respectively, for the solvent temperature of 30° C. The NRTL-PR property model and UNIFAC for estimating binary interaction parameters are recommended for modeling absorption of tar compounds in vegetable oils. Bench scale

  12. Ozone measurements in Amazonia - Dry season versus wet season (United States)

    Kirchhoff, V. W. J. H.; Da Silva, I. M. O.; Browell, Edward V.


    Recent ozone measurements taken in the Amazonian rain forest environment during the wet season (April-May 1987) are described, revealling new aspects of the regional atmospheric chemistry. The measurements were part of the Amazon Boundary Layer Experiment (ABLE 2B) mission and utilized UV absorption as a measurement technique to obtain surface ozone data; 20 ozonesondes were launched in order to obtain vertical ozone profiles used to describe the upper troposphere and stratosphere. The major differences in comparison to a previous dry season experiment, which found ozone concentrations to be lower in the whole troposphere by nearly a factor of 2, are stressed.

  13. Moisture separators and reheaters for wet steam turbines

    International Nuclear Information System (INIS)

    Gibbins, J.


    Moisture separator reheater (M.S.R.) units are now a well established feature of the wet steam cycle as associated with the various types of water cooled reactor. This paper describes the development of M.S.Rs. as supplied by GEC for turbine generators of up to 1200 MW ratings covering the design procedures used and the features required to ensure efficient and reliable operation. In addition to details of the M.S.R. design, the desirable features of the steam supply, venting and drain control systems are also discussed. The recent developments, as provided on current projects, are described. (author)

  14. Process for recovering uranium from wet process phosphoric acid (III)

    International Nuclear Information System (INIS)

    Pyrih, R.Z.; Rickard, R.S.; Carrington, O.F.


    Uranium is conventionally recovered from wet-process phosphoric acid by two liquid ion exchange steps using a mixture of mono- and disubstituted phenyl esters of orthophosphoric acid (OPPA). Efficiency of the process drops as the mono-OPPA is lost preferentially to the aqueous phase. This invention provides a process for the removal of the uranium process organics (OPPA and organic solvents) from the raffinate of the first liquid ion exchange step and their return to the circuit. The process organics are removed by a combination flotation and absorption step, which results in the recovery of the organics on beads of a hydrophobic styrene polymer


    Directory of Open Access Journals (Sweden)

    Xue Zhang


    Full Text Available Aluminium borate (Al₄B₂O₉ whiskers were successfully synthesized by the wet molten salt method at 800 oC through control the aluminum/boron atomic ratio and synthesis temperature. The as-received Al₄B₂O₉ whiskers were characterized by scanning electron microscopy (SEM, X-ray diffraction (XRD and thermal analysis. A solution-liquid-solid (SLS mechanism was proposed for the growth mechanism of the whiskers on the basis of the experimental phenomena and the TG-DSC data of the mixed raw materials.

  16. Evaluation of wet oxidation pretreatment for enzymatic hydrolysis of softwood

    DEFF Research Database (Denmark)

    Palonen, H.; Thomsen, A.B.; Tenkanen, M.


    , and the compositions of solid and liquid fractions were analyzed. The solid fraction after wet oxidation contained 58-64% cellulose, 2-16% hemicellulose, and 24-30% lignin. The pretreatment series gave information about the roles of lignin and hemicellulose in the enzymatic hydrolysis. The temperature...... of the pretreatment, the residual hemicellulose content of the substrate, and the type of the commercial cellulase preparation used were the most important factors affecting the enzymatic hydrolysis. The highest sugar yield in a 72-h hydrolysis, 79% of theoretical, was obtained using a pretreatment of 200degrees...

  17. Uranium recovery from wet-process phosphoric acid

    International Nuclear Information System (INIS)

    McCullough, J.F.; Phillips, J.F. Jr.; Tate, L.R.


    A method of recovering uranium from wet-process phosphoric acid is claimed where the acid is treated with a mixture of an ammonium salt or ammonia, a reducing agent, and then a miscible solvent. Solids are separated from the phosphoric acid liquid phase. The solid consists of a mixture of metal phosphates and uranium. It is washed free of adhering phosphoric acid with fresh miscible solvent. The solid is dried and dissolved in acid whereupon uranium is recovered from the solution. Miscible solvent and water are distilled away from the phosphoric acid. The distillate is rectified and water discarded. All miscible solvent is recovered for recycle. 5 claims

  18. Differences and commonalities impregnation of dry and wet sand

    Directory of Open Access Journals (Sweden)



    Full Text Available The article is devoted to research new methods of physic-chemical methods of preventing deflation to protect railways and highways from such phenomena as exogenous sand drifts. In particular, first studied the possibility of using binders in sand wet state. Results can significantly extend the scope of the method, and identified with particular impregnation maintaining stability requirements protective cover reduces both the concentration previously recommended binders, and their costs, thereby securing implementation in practice of shifting sands resource-saving technology.

  19. Scaling of wet granular flows in a rotating drum

    Directory of Open Access Journals (Sweden)

    Jarray Ahmed


    Full Text Available In this work, we investigate the effect of capillary forces and particle size on wet granular flows and we propose a scaling methodology that ensures the conservation of the bed flow. We validate the scaling law experimentally by using different size glass beads with tunable capillary forces. The latter is obtained using mixtures of ethanol-water as interstitial liquid and by increasing the hydrophobicity of glass beads with an ad-hoc silanization procedure. The scaling methodology in the flow regimes considered (slipping, slumping and rolling yields similar bed flow for different particle sizes including the angle of repose that normally increases when decreasing the particle size.

  20. Uranium tetrafluoride production via dioxide by wet process

    International Nuclear Information System (INIS)

    Aquino, A.R. de.


    The study for the wet way obtention of uranium tetrafluoride by the reaction of hydrofluoric acid and powder uranium dioxide, is presented. From the results obtained at laboratory scale a pilot plant was planned and erected. It is presently in operation for experimental data aquisition. Time of reaction, temperature, excess of reagents and the hydrofluoric acid / uranium dioxide ratio were the main parameters studied to obtain a product with the following characteristics: - density greater than 1 g/cm 3 , conversion rate greater than 96%, and water content equal to 0,2% that allows its application to heaxafluoride convertion or to magnesiothermic process. (author) [pt

  1. INTERATOM experience of cleaning sodium-wetted components

    International Nuclear Information System (INIS)

    Haubold, W.


    INTERATOM has been concerned since 1967 with the development, testing, and application of methods to clean sodium wetted components by moist nitrogen, vacuum distillation or alcohol. The activities of INTERATOM in this area have been reported at the IAEA Specialists Meeting on 'Decontamination of Plant Components from Sodium and Radioactivity' in Dounreay, April 9-12, 1973. The three cleaning methods mentioned above are practised at present, too - with minor modifications - by INTERATOM and in the facilities of the SNR project. This note summarizes the experiences of INTERATOM with methods of sodium removal since 1973

  2. Wet oxidation catalyzed by ruthenium supported on cerium (IV) oxides

    International Nuclear Information System (INIS)

    Imamura, S.; Fukuda, I.; Ishida, S.


    The activity of precious meta catalysts in the wet oxidation of organic compounds was investigated. Ruthenium was the most active catalyst among the precious metals examined, and cerium (IV) oxide was the most effective support. The Ru/Ce catalyst rivaled homogeneous copper catalyst, which is used in the practical wastewater treatment, for the oxidation of n-propyl alcohol, n-butyl alcohol, phenol, acetamide, poly (propylene glycol), and acetic acid. In addition, it was especially effective for the oxidation of some compounds with high oxygen content such as poly (ethylene glycol), ethylene glycol, formaldehyde, and formic acid

  3. Condition of research reactor spent nuclear fuels in wet storage

    International Nuclear Information System (INIS)

    Lambert, J.D.B.; Maksimkin, O.P.


    Full text: The condition of spent nuclear fuel (SNF) in wet storage at ten Soviet-designed research reactors has been assessed in the light of international experience in order to identify any associated safety issues. These reactors use Al-clad UO 2 -Al or U-Al alloy dispersion fuels of ≥20% enrichment that were fabricated in Russia; the reactors have been in operation since 1955-70. Although originally sent for reprocessing, much of the SNF generated over the last 25-30 years has been stored in fuel storage pools (FSPs) of variable water quality. The external condition of wet-stored SNF assemblies from the reactors surveyed varied from significant failure due to galvanic corrosion that was driven by poor water quality, through gradual pitting caused by slightly impure water, to a stable condition of no observable change in the oxidized Al alloy surface of the irradiated fuel. SNF stability in wet storage seems to depend on three factors: Al being the sole metal in the FSP (to avoid galvanic action); good water chemistry to suppress attack of the oxide layer by aggressive ions like Cl - , and gentle handling to limit physical damage to the oxide layer. If one of these factors is not satisfied, SNF degradation will take place; if more than one factor is not satisfied, failure of the Al cladding may occur. In general, however, even SNF failure in wet storage does not appear to raise significant safety concerns. A possible exception is where galvanic corrosion combined with poor water quality has caused massive fuel failure, as at the RA reactor in Belgrade. A potential safety problem was identified at reactors where unalloyed Al liners had been used in the FSPs. Unlike SNF that develops a protective oxide layer in-reactor, these Al liners were unprotected and prone to significant corrosion during an ill-defined early period of poor water quality. The risk of losing water from FSPs due to liner failure should be evaluated for all research reactors. Where the risk

  4. Aerial wetting contact angle measurement using confocal microscopy


    Chesna, Jacob W.; Wiedmaier, Bob F.; Wang, Jinlin; Samara, Ayman; Leach, Richard K.; Her, Tsing-Hua; Smith, Stuart T.


    A method is presented in which the wetting contact angle of a sessile drop is acquired aerially using confocal techniques to measure the radius and the height of a droplet deposited on a planar surface. The repeatability of this method is typically less than 0.25°, and often less than 0.1°, for droplet diameters less than 1 mm. To evaluate accuracy of this method, an instrument uncertainty budget is developed, which predicts a combined uncertainty of 0.91° for a 1 mm diameter water droplet wi...

  5. Expediency of wet-mix shotcreting in mines of Vostoktsvetmet (United States)

    Shaposhnik, YuN


    This paper offers a substantiation of the transition from heavy and difficult-to-install steel frame support to the cheaper and simpler reinforced shotcrete lining (at the same bearing-capacity of the support). The process line for the preparation of the shotcrete mix is designed. The author of the paper presents calculation of the material inputs and labor costs of installation of different support types in Kazakhstan Mines. The economic efficiency of the wet-mix shotcrete spraying technology is illustrated in terms of Orlov and Artemevsk Mines.

  6. ['Mercenary wet-nurses': the discourse of medical doctors and portraits of the wet-nurses--Brazil in the second half of the 19th century]. (United States)

    Koutsoukos, Sandra Sofia Machado


    The article explores the theme of wet-nurses using photographs and theses of medical doctors during the second half of the 19th century. The doctors at that time condemned the indiscriminate use of wet-nurses and tried to encourage construction of the 'new mother' image, one who ought to breast feed her own children. They approached the complexity of the feeding subject (by mother, wet-nurse, animal or object) at that time and the problems arising from it for the parties involved: the white baby, the black baby, the wet-nurse, the mother of the white baby, the seignorial family involved and medical doctors. Photos are highlighted of wet-nurses with children in an attitude that was intended to be 'positive' to demonstrate harmony and affection and, apparently, contradicting the debates regarding them.

  7. Geckolike high shear strength by carbon nanotube fiber adhesives (United States)

    Maeno, Y.; Nakayama, Y.


    Carbon nanotube adhesives can adhere strongly to surfaces as a gecko does. The number of carbon nanotube layers is an important determinant of the contact area for adhesion. Balancing the catalyst ratio and buffer layer used for chemical vapor deposition processing controls the number of carbon nanotube layers and their distribution. The features of carbon nanotubes determine the shear strength of adhesion. Carbon nanotubes with a broad distribution of layers exhibit enhanced shear strength with equivalent adhesive capability to that of a natural Tokay Gecko (Gekko gecko)

  8. On equivalent roughness of mobile bed at high shear stress

    Czech Academy of Sciences Publication Activity Database

    Matoušek, Václav; Krupička, Jan


    Roč. 57, č. 3 (2009), s. 191-199 ISSN 0042-790X R&D Projects: GA ČR GA103/06/0428 Institutional research plan: CEZ:AV0Z20600510 Keywords : bed shear * experiment * hydraulic transport * sediment transport Subject RIV: BK - Fluid Dynamics Impact factor: 1.000, year: 2009

  9. Pressurized wet digestion in open vessels (T11)

    International Nuclear Information System (INIS)

    Kettisch, P.; Maichin, P.; Zischka, M.; Knapp, G.


    Full text: Pressurized wet digestion in closed vessels, microwave assisted or with conventional conductive heating, is the most important sample preparation technique for digestion or leaching procedures in element analysis. In comparison to open vessel digestion closed vessel digestion methods have many advantages, but there is one disadvantage - complex and expensive vessel designs. A new technique - pressurized wet digestion in open vessels - combine the advantages of closed vessel sample digestion with the application of simple and cheap open vessels made of quartz or PFA. The vessels are placed in a high pressure Asher HPA, which is adapted with a Teflon liner and filled partly with water. The analytical results with 30 ml quartz vessels, 22 ml PFA vessels and 1.5 ml PIA auto sampler cups will be shown. In principle every dimensions of vessels can be used. The vessels are loaded with sample material (max. 1.5 g with quartz vessels, max. 0.5 g with PFA vessels and 50 mg with auto sampler cups) and digestion reagent. Afterwards the vessels are simply covered with PTFE stoppers and not sealed. The vessels are transferred into a special adapted HPA and digested at temperatures up to 270 o C. The digestion time is 90 min. and cooling down to room temperature 30 min. The analytical results of CRM's are within the certified values and no cross contamination and losses of volatile elements could be observed. (author)

  10. The development of a 'wet leg' pathway for chronic oedema. (United States)

    Morgan, Karen; Thomas, Melanie


    Chronic oedema and leaking lymphorrhoea can be distressing and challenging for patients to live with. This article introduces the Chronic Oedema 'Wet Leg' Pathway, which became an output from the Lymphoedema Network Wales 'On the Ground Education Project' ( Thomas et al, 2017 ). The evidence-based pathway provides nurses and therapists with clear guidelines to support prompt, efficient and effective management of all patients with chronic oedema and wet legs. This article presents the evidence and demonstrates the benefits of timely active treatment for all patients with leaking lymphorrhoea, which includes decreasing pain and improving mobility and daily activities. Other benefits include reducing the risk of cellulitis and the development of chronic wounds. The pathway also demonstrates opportunities for the NHS by decreasing both the number of community nursing visits and the number of wound dressings used. By actively treating symptoms-rather than simply mopping up the leaking lymphorrhoea-this pathway demonstrates value-based health care by reducing waste, harm and variation within the NHS.

  11. Improving energetics of triacylglyceride extraction from wet oleaginous microbes. (United States)

    Willis, Robert M; McCurdy, Alex T; Ogborn, Mariah K; Wahlen, Bradley D; Quinn, Jason C; Pease, Leonard F; Seefeldt, Lance C


    Oleaginous microbes can upgrade carbon to lipids, which can be used as a feedstock to produce renewable replacements for petroleum-based compounds. Efficient extraction of lipids from oleaginous microbes typically involves dewatering and drying of the biomass. Problematically, drying often requires an amount of energy approaching that available from the cells. Here, we report an approach for the high efficiency extraction of triacylglycerides (TAG) from wet oleaginous microbes, bypassing the drying process. Solvent candidates for extraction of wet oleaginous biomass were identified using ASPEN's databases to determine an activity based selectivity coefficient. Optimal extraction conditions were determined which resulted in >91% extraction of TAG from yeast, bacteria, and microalgae. Experimental data was integrated into system models to evaluate the energetics of the processes compared to traditional extraction methods. The net energy ratio (NER) of a traditional dry solvent extraction is 0.84, whereas the approach presented here has a NER of 0.34 for yeast. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Lunar Surface Systems Wet-Bath Design Evaluation (United States)

    Thompson, Shelby; Szabo, Rich; Howard, Robert


    The goal of the current evaluation was to examine five different wet-bath architectural design concepts. The primary means of testing the concepts required participants to physically act-out a number of functional tasks (e.g., shaving, showering, changing clothes, maintenance) in order to give judgments on the affordance of the volume as based on the design concepts. Each of the concepts was designed in such a way that certain features were exploited - for example, a concept may have a large amount of internal stowage, but minimum amount of usable space to perform tasks. The results showed that the most preferred concept was one in which stowage and usable space were balanced. This concept allowed for a moderate amount of stowage with some suggested redesign, but would not preclude additional personal items such as clothing. This concept also allowed for a greater distance to be achieved between the toilet and the sink with minimum redesign, which was desirable. Therefore, the all-in-one (i.e., toilet, sink, and shower all occupying a single volume) wet-bath concept seemed to be a viable solution in which there is a minimal amount of overall volume available with certain lunar habitat configurations.

  13. Unsteady coupling effects of wet steam in steam turbines flows

    International Nuclear Information System (INIS)

    Blondel, Frederic


    In addition to conventional turbomachinery problems, both the behavior and performances of steam turbines are highly dependent on the vapour thermodynamic state and the presence of a liquid phase. EDF, the main French electricity producer, is interested in further developing its' modelling capabilities and expertise in this area to allow for operational studies and long-term planning. This PhD thesis explores the modelling of wetness formation and growth in a steam turbine and an analysis of the coupling between the liquid phase and the main flow unsteadiness. To this end, the work in this thesis took the following approach. Wetness was accounted for using a homogeneous model coupled with transport equations to take into account the effects of non-equilibrium phenomena, such as the growth of the liquid phase and nucleation. The real gas attributes of the problem demanded adapted numerical methods. Before their implementation in the 3D elsA solver, the accuracy of the chosen models was tested using a developed one-dimensional nozzle code. In this manner, various condensation models were considered, including both poly-dispersed and monodispersed behaviours of the steam. Finally, unsteady coupling effects were observed from several perspectives (1D, 1D - 3D, 3D), demonstrating the ability of the method of moments to sustain unsteady phenomena which were not apparent in a simple monodispersed model. (author)

  14. Wetting kinetics of oil mixtures on fluorinated model cellulose surfaces. (United States)

    Aulin, Christian; Shchukarev, Andrei; Lindqvist, Josefina; Malmström, Eva; Wågberg, Lars; Lindström, Tom


    The wetting of two different model cellulose surfaces has been studied; a regenerated cellulose (RG) surface prepared by spin-coating, and a novel multilayer film of poly(ethyleneimine) and a carboxymethylated microfibrillated cellulose (MFC). The cellulose films were characterized in detail using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). AFM indicates smooth and continuous films on a nanometer scale and the RMS roughness of the RG cellulose and MFC surfaces was determined to be 3 and 6 nm, respectively. The cellulose films were modified by coating with various amounts of an anionic fluorosurfactant, perfluorooctadecanoic acid, or covalently modified with pentadecafluorooctanyl chloride. The fluorinated cellulose films were used to follow the spreading mechanisms of three different oil mixtures. The viscosity and surface tension of the oils were found to be essential parameters governing the spreading kinetics on these surfaces. XPS and dispersive surface energy measurements were made on the cellulose films coated with perfluorooctadecanoic acid. A strong correlation was found between the surface concentration of fluorine, the dispersive surface energy and the contact angle of castor oil on the surface. A dispersive surface energy less than 18 mN/m was required in order for the cellulose surface to be non-wetting (theta e>90 degrees ) by castor oil.

  15. Static and Dynamic Wetting Behavior of Triglycerides on Solid Surfaces. (United States)

    Michalski; Saramago


    Triglyceride wetting properties on solid surfaces of different hydro-phobicities were investigated using three different methods, namely, the sessile drop method for static contact angle measurements, the Wilhelmy method for dynamic contact angle measurements, and the captive bubble method to investigate thin triglyceride film stability. For solid surfaces having a surface free energy higher than the surface tension of triglycerides (tributyrin, tricaprylin, and triolein), a qualitative correlation was observed between wetting and solid/triglyceride relative hydrophobicities. On surfaces presenting extreme hydrophobic or hydrophilic properties, medium-chain triglycerides had a behavior similar to that of long-chain unsaturated ones. On a high-energy surface (glass), tricaprylin showed an autophobic effect subsequent to molecular adsorption in trident conformation on the solid, observed with the three methods. Thin triglyceride films between an air bubble and a solid surface were stable for a short time, for solids with a surface free energy larger than the triglyceride surface tension. If the solid surface had a lower surface free energy, the thin film collapsed after a time interval which increased with triglyceride viscosity. Copyright 2000 Academic Press.

  16. Modeling of Direct Contact Wet Cooling Tower in ETRR-2

    International Nuclear Information System (INIS)

    El Khatib, H.H.; Ismail, A.L.; ElRefaie, M.E.


    The Egyptian Testing and Research Reactor no.2 (ETRR-2) was commissioned at 1997 with maximum power 22 MW for research purposes; an induced draft wet cooling tower (counter flow type) was putted in operation in 2003 instead of the first one. Investigations are achieved to evaluate cooling tower performance to guarantee that the cooling tower capable to dissipate heat generated in reactor core. Merkel and Poppe analysis was applied to simulate this cooling tower packing. Merkel analysis was applied to predict water outlet temperature from cooling tower and also to show the effect of ambient conditions on this temperature. Poppe analysis was applied to predict Merkel number which evaluate cooling tower. The Runge-Kutta numerical method was applied to solve the differential equations in this model and an engineering equation solver (EES) is the language used to model the cooling tower. This research illustrates that the cooling tower achieves good performance in various sever ambient condition at maximum operating condition of reactor power. The results show that at severe summer condition of wet bulb temperature equals 24 degree c and tower inlet temperature equals 37 degree c, the outlet water temperature equals 30.4 degree c from cooling tower, while the Merkel number is be found 1.253

  17. Transmission studies involving a wet fowl pox isolate. (United States)

    Eleazer, T H; Harrell, J S; Blalock, H G


    An isolate of fowl pox (FP) virus from a case of "wet" pox in commercial white leghorn (WL) pullets was used to expose WL cockerels via the comb-scratch (CS), eye-drop (ED), or laryngeal-swab (LS) route. Seven days postinoculation (PI), the groups challenged via CS had scabby proliferative pox lesions at the challenge site, the groups challenged via LS had slight dyspnea and rales, and 20% of the cockerels challenged via ED had mild conjunctivitis and lacrimation. By termination of the trial on day 21 PI, the CS-challenged groups had developed pronounced pox lesions. The LS-challenged groups showed severe dyspnea and rales with pronounced raised plaque-like lesions at the opening to the trachea and extending into the upper quarter of the trachea with heavy yellowish caseous exudate partly occluding the glottis. The ED-challenged groups had severe lacrimation and conjunctivitis and small pox lesions on the face, comb, and wattles; 12 of 18 had proliferative lesions on the oral mucosa in the area of the larynx. Forty-five percent of the LS-challenged groups died of suffocation. Pox virus was re-isolated from tissues in all treatment groups. Wet pox transmission appears to be possible via the LS and ED routes.

  18. INTRODUCTION: Wetting and dewetting in bio-related systems (United States)

    Herminghaus, S.


    Research on such genuinely soft-matter related phenomena as wetting and dewetting would not be complete without reminiscence to biological systems. The recent stir around what has been known as the lotus effect, the amazing ultra-hydrophobic properties of many plants, has highlighted the interconnections of wetting with bio-systems. In the first paper of this section (Mock et al), a `biomimetic' system is conceived which imitates the properties of plant leaves with elastic hairs. The synthesis of such a system turns out to be tricky, but the progress is encouraging. The next three papers deal with surfactant layers, as they occur in many biological systems, such as the plasma membrane. Various experimental techniques, such as fluorescence microscopy (Tanaka et al), neutron reflectivity (Steitz et al), and x-ray scattering (Ahrens et al), are demonstrated as powerful tools for their investigation. The last paper (Heim et al) takes us back to where we started: the morphologies emerging upon dewetting of a liquid. This time, the full diversity of patterns is shown which appears in the deposited solute, once the liquid has evaporated. The motivation of this work is the morphology of deposition of DNA on bio-chips, which may affect the readout results of such devices. It is shown that although much can already be understood, a lot of work has still to be done, and many beautiful mechanisms may still be discovered.

  19. Diagnosis of pulmonary pneumocystosis by microscopy on wet mount preparations

    Directory of Open Access Journals (Sweden)

    BAVA Amadeo Javier


    Full Text Available We have compared the searching of the presence of "honeycomb" structures by direct microscopy on wet mount preparations with the direct immunofluorescence (DIF for the diagnosis of Pneumocystis carinii pneumonia (PCP in 115 bronchoalveolar (BAL fluids. The samples belonged to 115 AIDS patients; 87 with presumptive diagnosis of PCP and 28 with presumptive diagnosis other than PCP. The obtained results were coincident in 114 out of 115 studied samples (27 were positive and 87 negative with both techniques. A higher percentage of positive results (32.18% among patients with presumptive diagnosis of PCP with respect to those with presumptive diagnosis other than PCP (3.57% was observed. One BAL fluid was positive only with DIF, showed scarce and isolated P. carinii elements and absence of typical "honeycomb" structures. The searching for "honeycomb" structures by direct microscopy on wet mount preparations could be considered as a cheap and rapid alternative for diagnosis of PCP when other techniques are not available or as screening test for DIF. This method showed a sensitivity close to DIF when it was applied to BAL fluids of AIDS patients with poor clinical condition and it was performed by an experienced microscopist.

  20. NOx Effects on Photochemical Aging of Urban Wet Particles (United States)

    Lim, Y. B.; Seo, J.; Kim, J. Y.; Turpin, B. J.


    Aqueous chemistry in aerosol liquid water (ALW) has been considered an important pathway of particle formation, which is expected to improve current models; however, little is known about NOx effects on aqueous chemistry in wet urban particulate matter (PM). Here we show photochemical aging of wet aerosols at modest urban conditions conducted in a smog chamber and provide atmospheric evidence of these chamber reactions. At high relative humidity, HNO3, the main sink of photochemistry of NOx, initiates water uptake into aerosols and ALW in turn facilitates aqueous chemistry. The hygroscopic growth was significant, and aqueous chemistry led to mainly non-radical products, such as organonitrates and oligomers. This multiphase chemistry contributes to particle aging during a haze event in Seoul, a megacity in East Asia. PM2.5 at Seoul, a downwind site at high NOx conditions, and reference PM2.5 at Deokjeok Island, an upwind site that has no emission source, during winter including the haze period were analyzed. Chemical components of Seoul haze particles can be explained by photochemical aging of transported particles in the presence of NOx. East Asian megacities including Seoul suffer from high concentration particles, yet the formation is poorly understood. Our finding of chemical aging and secondary formation highlights the importance of multiphase reactions, including gas-phase photochemistry at high NOx and aqueous chemistry in ALW, which need to be incorporated into air quality models to improve predictions for public health.