Sample records for hydrophobic packing materials

  1. Packing material formulation for odorous emission biofiltration. (United States)

    Gaudin, François; Andres, Yves; Le Cloirec, Pierre


    In biological gas treatment, like biofiltration of volatile organic compounds or odorous substances, the microbial nutritional needs could be a key factor of the process. The aim of this work is to propose a new packing material able to provide the lacking nutrients. In the first part of this study, two kinds of material composed of calcium carbonate, an organic binder and two different nitrogen sources, ammonium phosphate and urea phosphate (UP), were compared. The new supports present bulk densities between 0.88 and 1.15g cm(-3), moisture retention capacities close to 50% and 70%, and water cohesion capacities greater than six months for the material with 20% binder. In the second part, oxygen consumption measurements in liquid experiments show that these packing materials could enhance bacterial growth compared to pine bark or pozzolan and have no inhibitory effect. The biodegradation of different substrates (sodium sulfide and ammonia) and the support colonization by the biomass were evaluated. Finally, UP 20 was chosen and tested in a hydrogen sulfide or ammoniac biofiltration process. This showed that, for H2S concentrations greater than 100mg m(-3), UP 20 has a real advantage over pine bark or pozzolan.

  2. Differential Effects of Hydrophobic Core Packing Residues for Thermodynamic and Mechanical Stability of a Hyperthermophilic Protein. (United States)

    Tych, Katarzyna M; Batchelor, Matthew; Hoffmann, Toni; Wilson, Michael C; Hughes, Megan L; Paci, Emanuele; Brockwell, David J; Dougan, Lorna


    Proteins from organisms that have adapted to environmental extremes provide attractive systems to explore and determine the origins of protein stability. Improved hydrophobic core packing and decreased loop-length flexibility can increase the thermodynamic stability of proteins from hyperthermophilic organisms. However, their impact on protein mechanical stability is not known. Here, we use protein engineering, biophysical characterization, single-molecule force spectroscopy (SMFS), and molecular dynamics (MD) simulations to measure the effect of altering hydrophobic core packing on the stability of the cold shock protein TmCSP from the hyperthermophilic bacterium Thermotoga maritima. We make two variants of TmCSP in which a mutation is made to reduce the size of aliphatic groups from buried hydrophobic side chains. In the first, a mutation is introduced in a long loop (TmCSP L40A); in the other, the mutation is introduced on the C-terminal β-strand (TmCSP V62A). We use MD simulations to confirm that the mutant TmCSP L40A shows the most significant increase in loop flexibility, and mutant TmCSP V62A shows greater disruption to the core packing. We measure the thermodynamic stability (ΔGD-N) of the mutated proteins and show that there is a more significant reduction for TmCSP L40A (ΔΔG = 63%) than TmCSP V62A (ΔΔG = 47%), as might be expected on the basis of the relative reduction in the size of the side chain. By contrast, SMFS measures the mechanical stability (ΔG*) and shows a greater reduction for TmCSP V62A (ΔΔG* = 8.4%) than TmCSP L40A (ΔΔG* = 2.5%). While the impact on the mechanical stability is subtle, the results demonstrate the power of tuning noncovalent interactions to modulate both the thermodynamic and mechanical stability of a protein. Such understanding and control provide the opportunity to design proteins with optimized thermodynamic and mechanical properties.

  3. Surface analysis of selected hydrophobic materials (United States)

    Wisniewska, Sylwia Katarzyna

    This dissertation contains a series of studies on hydrophobic surfaces by various surface sensitive techniques such as contact angle measurements, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Hydrophobic surfaces have been classified as mineral surfaces, organic synthetic surfaces, or natural biological surfaces. As a model hydrophobic mineral surface, elemental sulfur has been selected. The sulfur surface has been characterized for selected allotropic forms of sulfur such as rhombic, monoclinic, plastic, and cyclohexasulfur. Additionally, dextrin adsorption at the sulfur surface was measured. The structure of a dextrin molecule showing hydrophobic sites has been presented to support the proposed hydrophobic bonding nature of dextrin adsorption at the sulfur surface. As a model organic hydrophobic surface, primary fatty amines such as dodecylamine, hexadecylamine, and octadecylamine were chosen. An increase of hydrophobicity, significant changes of infrared bands, and surface topographical changes with time were observed for each amine. Based on the results it was concluded that hydrocarbon chain rearrangement associated with recrystallization took place at the surface during contact with air. A barley straw surface was selected as a model of biological hydrophobic surfaces. The differences in the contact angles for various straw surfaces were explained by the presence of a wax layer. SEM images confirmed the heterogeneity and complexity of the wax crystal structure. AFM measurements provided additional structural details including a measure of surface roughness. Additionally, straw degradation as a result of conditioning in an aqueous environment was studied. Significant contact angle changes were observed as soon as one day after conditioning. FTIR studies showed a gradual wax layer removal due to straw surface decomposition. SEM and AFM images revealed topographical changes and biological

  4. Effects of Different Packing Materials on Cotton Fires (United States)

    Zhou, Yanzhao; Liu, Wanfu; Ni, Zhaopeng; Wang, Lu; Gao, Bo


    The aim of this study is to investigate the effects of different packing materials on cotton fires. After the cotton bale is ignited, the caving area, the mass loss rate and the temperature variation of cotton bales were measured. Through the experiment, it was found that Cotton bale packed with Plastic belt has the phenomenon of collapse, but the cotton bale packed with Steel ribbon does not happen to collapse. The mass loss rate of the Cotton bale packed with Plastic belt is faster than that of the cotton bale packed with Steel ribbon, and the temperature is higher.

  5. [Stability of oral rehydration solutions in various packing materials]. (United States)

    Santoro, M I; Hackmann, E R; Moudatsos, K M


    The aim of this research was to provide data to select an ideal packing material to preserve the integrity of oral rehydration salts (ORS), a therapeutic formulation that is essential in developing countries. Previous research had verified that water is the factor that most affects ORS stability. For this research, a pharmaceutical industry prepared an ORS batch that was packed in six different types of packing materials. The humidity determination was made after storage of samples during 36 weeks at room temperature, at room temperature with 76% relative humidity, and at 40 degrees C with 80% relative humidity. The moisture in the samples was measured at pre-determined intervals using methods like loss on drying at 50 degrees C and the Karl Fischer method. The results indicated that the most efficient packing material was composed of 18g polyester, 35 g aluminum, and 50 g polyethylene (packing material no. 6).

  6. Thermal effects of water intrusion in hydrophobic nanoporous materials. (United States)

    Karbowiak, Thomas; Paulin, Christian; Ballandras, Anthony; Weber, Guy; Bellat, Jean-Pierre


    Liquid water intrusion in hydrophobic nanoporous silicalite-1, a pure siliceous zeolite, in isothermal conditions under high pressure produces an endothermic effect. After intrusion, confined water in zeolite pores is in a different state from that of the liquid bulk water. Such forced intrusion also chemically modifies the material and tends to render it slightly more hydrophilic.

  7. Single molecule force spectroscopy reveals critical roles of hydrophobic core packing in determining the mechanical stability of protein GB1. (United States)

    Bu, Tianjia; Wang, Hui-Chuan Eileen; Li, Hongbin


    Understanding molecular determinants of protein mechanical stability is important not only for elucidating how elastomeric proteins are designed and functioning in biological systems but also for designing protein building blocks with defined nanomechanical properties for constructing novel biomaterials. GB1 is a small α/β protein and exhibits significant mechanical stability. It is thought that the shear topology of GB1 plays an important role in determining its mechanical stability. Here, we combine single molecule atomic force microscopy and protein engineering techniques to investigate the effect of side chain reduction and hydrophobic core packing on the mechanical stability of GB1. We engineered seven point mutants and carried out mechanical φ-value analysis of the mechanical unfolding of GB1. We found that three mutations, which are across the surfaces of two subdomains that are to be sheared by the applied stretching force, in the hydrophobic core (F30L, Y45L, and F52L) result in significant decrease in mechanical unfolding force of GB1. The mechanical unfolding force of these mutants drop by 50-90 pN compared with wild-type GB1, which unfolds at around 180 pN at a pulling speed of 400 nm/s. These results indicate that hydrophobic core packing plays an important role in determining the mechanical stability of GB1 and suggest that optimizing hydrophobic interactions across the surfaces that are to be sheared will likely be an efficient method to enhance the mechanical stability of GB1 and GB1 homologues.

  8. Noncontact ultrasound detection of exotic insects in wood packing materials (United States)

    Mary R. Fleming; Dinesh K. Agrawal; Mahesh C. Bhardwaj; Leah S. Bauer; John J. Janowiak; Deborah L. Miller; Jeffrey E. Shield; Kelli Hoover; Rustum Roy


    Nondestructive methods for detection of wood-boring insects such as the Asian longhorned beetle (ALB), Anoplophora glabripennis (Coleoptera: Cerambycidae) inside solid wood packing materials is a valuable tool in the fight to exclude exotic insects from attacking a nation?s timber resources. Nondestructive, non-contact, ultrasound was investigated as...

  9. Transistor memory devices with large memory windows, using multi-stacking of densely packed, hydrophobic charge trapping metal nanoparticle array. (United States)

    Cho, Ikjun; Kim, Beom Joon; Ryu, Sook Won; Cho, Jeong Ho; Cho, Jinhan


    Organic field-effect transistor (OFET) memories have rapidly evolved from low-cost and flexible electronics with relatively low-memory capacities to memory devices that require high-capacity memory such as smart memory cards or solid-state hard drives. Here, we report the high-capacity OFET memories based on the multilayer stacking of densely packed hydrophobic metal NP layers in place of the traditional transistor memory systems based on a single charge trapping layer. We demonstrated that the memory performances of devices could be significantly enhanced by controlling the adsorption isotherm behavior, multilayer stacking structure and hydrophobicity of the metal NPs. For this study, tetraoctylammonium (TOA)-stabilized Au nanoparticles (TOA-Au(NPs)) were consecutively layer-by-layer (LbL) assembled with an amine-functionalized poly(amidoamine) dendrimer (PAD). The formed (PAD/TOA-Au(NP))(n) films were used as a multilayer stacked charge trapping layer at the interface between the tunneling dielectric layer and the SiO2 gate dielectric layer. For a single AuNP layer (i.e. PAD/TOA-Au(NP))1) with a number density of 1.82 × 10(12) cm(-2), the memory window of the OFET memory device was measured to be approximately 97 V. The multilayer stacked OFET memory devices prepared with four Au(NP) layers exhibited excellent programmable memory properties (i.e. a large memory window (ΔV(th)) exceeding 145 V, a fast switching speed (1 μs), a high program/erase (P/E) current ratio (greater than 10(6)) and good electrical reliability) during writing and erasing over a relatively short time scale under an operation voltage of 100 V applied at the gate.

  10. Numerical study on hygroscopic material drying in packed bed

    Directory of Open Access Journals (Sweden)

    M. Stakić


    Full Text Available The paper addresses numerical simulation for the case of convective drying of hygroscopic material in a packed bed, analyzing agreement between the simulated and the corresponding experimental results. In the simulation model of unsteady simultaneous one-dimensional heat and mass transfer between gas phase and dried material, it is assumed that the gas-solid interface is at thermodynamic equilibrium, while the drying rate of the specific product is calculated by applying the concept of a "drying coefficient". Model validation was done on the basis of the experimental data obtained with potato cubes. The obtained drying kinetics, both experimental and numerical, show that higher gas (drying agent velocities (flow-rates, as well as lower equivalent grain diameters, induce faster drying. This effect is more pronounced for deeper beds, because of the larger amount of wet material to be dried using the same drying agent capacity.

  11. Method for immobilizing particulate materials in a packed bed (United States)

    Even, Jr., William R.; Guthrie, Stephen E.; Raber, Thomas N.; Wally, Karl; Whinnery, LeRoy L.; Zifer, Thomas


    The present invention pertains generally to immobilizing particulate matter contained in a "packed" bed reactor so as to prevent powder migration, compaction, coalescence, or the like. More specifically, this invention relates to a technique for immobilizing particulate materials using a microporous foam-like polymer such that a) the particulate retains its essential chemical nature, b) the local movement of the particulate particles is not unduly restricted, c) bulk powder migration and is prevented, d) physical and chemical access to the particulate is unchanged over time, and e) very high particulate densities are achieved. The immobilized bed of the present invention comprises a vessel for holding particulate matter, inlet and an outlet ports or fittings, a loosely packed bed of particulate material contained within the vessel, and a three dimensional porous matrix for surrounding and confining the particles thereby fixing the movement of individual particle to a limited local position. The established matrix is composed of a series of cells or chambers comprising walls surrounding void space, each wall forming the wall of an adjacent cell; each wall containing many holes penetrating through the wall yielding an overall porous structure and allowing useful levels of gas transport.

  12. Exploiting the bead-injection approach in the integrated sequential injection Lab-on-Valve format using hydrophobic packing materials for on-line matrix removal and preconcentration of trace levels of cadmium in environmental and biological samples via formation of non-charged chelates prior to ETAAS detection

    DEFF Research Database (Denmark)

    Miró, Manuel; Jonczyk, Sylwia; Wang, Jianhua


    The concept of renewable microcolumns within the conduits of an automated single injection lab-on-valve system was exploited in a sorption/elution fashion using sorbents of hydrophobic nature. The scheme's practical applicability was demonstrated for the electrothermal atomic absorption...... spectrometry determination of trace level concentrations of cadmium in complex matrices. Statistical comparisons between the proposed procedure and certified values revealed no significant differences at the 95% confidence level....

  13. Recent advances in food-packing, pharmaceutical and biomedical applications of zein and zein-based materials. (United States)

    Corradini, Elisângela; Curti, Priscila S; Meniqueti, Adriano B; Martins, Alessandro F; Rubira, Adley F; Muniz, Edvani Curti


    Zein is a biodegradable and biocompatible material extracted from renewable resources; it comprises almost 80% of the whole protein content in corn. This review highlights and describes some zein and zein-based materials, focusing on biomedical applications. It was demonstrated in this review that the biodegradation and biocompatibility of zein are key parameters for its uses in the food-packing, biomedical and pharmaceutical fields. Furthermore, it was pointed out that the presence of hydrophilic-hydrophobic groups in zein chains is a very important aspect for obtaining material with different hydrophobicities by mixing with other moieties (polymeric or not), but also for obtaining derivatives with different properties. The physical and chemical characteristics and special structure (at the molecular, nano and micro scales) make zein molecules inherently superior to many other polymers from natural sources and synthetic ones. The film-forming property of zein and zein-based materials is important for several applications. The good electrospinnability of zein is important for producing zein and zein-based nanofibers for applications in tissue engineering and drug delivery. The use of zein's hydrolysate peptides for reducing blood pressure is another important issue related to the application of derivatives of zein in the biomedical field. It is pointed out that the biodegradability and biocompatibility of zein and other inherent properties associated with zein's structure allow a myriad of applications of such materials with great potential in the near future.

  14. Recent Advances in Food-Packing, Pharmaceutical and Biomedical Applications of Zein and Zein-Based Materials

    Directory of Open Access Journals (Sweden)

    Elisângela Corradini


    Full Text Available Zein is a biodegradable and biocompatible material extracted from renewable resources; it comprises almost 80% of the whole protein content in corn. This review highlights and describes some zein and zein-based materials, focusing on biomedical applications. It was demonstrated in this review that the biodegradation and biocompatibility of zein are key parameters for its uses in the food-packing, biomedical and pharmaceutical fields. Furthermore, it was pointed out that the presence of hydrophilic-hydrophobic groups in zein chains is a very important aspect for obtaining material with different hydrophobicities by mixing with other moieties (polymeric or not, but also for obtaining derivatives with different properties. The physical and chemical characteristics and special structure (at the molecular, nano and micro scales make zein molecules inherently superior to many other polymers from natural sources and synthetic ones. The film-forming property of zein and zein-based materials is important for several applications. The good electrospinnability of zein is important for producing zein and zein-based nanofibers for applications in tissue engineering and drug delivery. The use of zein’s hydrolysate peptides for reducing blood pressure is another important issue related to the application of derivatives of zein in the biomedical field. It is pointed out that the biodegradability and biocompatibility of zein and other inherent properties associated with zein’s structure allow a myriad of applications of such materials with great potential in the near future.

  15. Effect of material flexibility on the thermodynamics and kinetics of hydrophobically induced evaporation of water. (United States)

    Altabet, Y Elia; Haji-Akbari, Amir; Debenedetti, Pablo G


    The evaporation of water induced by confinement between hydrophobic surfaces has received much attention due to its suggested functional role in numerous biophysical phenomena and its importance as a general mechanism of hydrophobic self-assembly. Although much progress has been made in understanding the basic physics of hydrophobically induced evaporation, a comprehensive understanding of the substrate material features (e.g., geometry, chemistry, and mechanical properties) that promote or inhibit such transitions remains lacking. In particular, comparatively little research has explored the relationship between water's phase behavior in hydrophobic confinement and the mechanical properties of the confining material. Here, we report the results of extensive molecular simulations characterizing the rates, free energy barriers, and mechanism of water evaporation when confined between model hydrophobic materials with tunable flexibility. A single-order-of-magnitude reduction in the material's modulus results in up to a nine-orders-of-magnitude increase in the evaporation rate, with the corresponding characteristic time decreasing from tens of seconds to tens of nanoseconds. Such a modulus reduction results in a 24-orders-of-magnitude decrease in the reverse rate of condensation, with time scales increasing from nanoseconds to tens of millions of years. Free energy calculations provide the barriers to evaporation and confirm our previous theoretical predictions that making the material more flexible stabilizes the confined vapor with respect to liquid. The mechanism of evaporation involves surface bubbles growing/coalescing to form a subcritical gap-spanning tube, which then must grow to cross the barrier.

  16. Effect of Hydrophobization on Wetting, Drying and Salt Crystallization in Porous Materials

    NARCIS (Netherlands)

    Shahidzadeh, N.


    We discuss the major role played by both the wetting properties of the porous material and the boundary conditions on the drying process. For hydrophobic materials, it will be shown how under some circumstances the evaporation rate becomes lower in the presence of an air flow over the surface than

  17. Material selection and assembly method of battery pack for compact electric vehicle (United States)

    Lewchalermwong, N.; Masomtob, M.; Lailuck, V.; Charoenphonphanich, C.


    Battery packs become the key component in electric vehicles (EVs). The main costs of which are battery cells and assembling processes. The battery cell is indeed priced from battery manufacturers while the assembling cost is dependent on battery pack designs. Battery pack designers need overall cost as cheap as possible, but it still requires high performance and more safety. Material selection and assembly method as well as component design are very important to determine the cost-effectiveness of battery modules and battery packs. Therefore, this work presents Decision Matrix, which can aid in the decision-making process of component materials and assembly methods for a battery module design and a battery pack design. The aim of this study is to take the advantage of incorporating Architecture Analysis method into decision matrix methods by capturing best practices for conducting design architecture analysis in full account of key design components critical to ensure efficient and effective development of the designs. The methodology also considers the impacts of choice-alternatives along multiple dimensions. Various alternatives for materials and assembly techniques of battery pack are evaluated, and some sample costs are presented. Due to many components in the battery pack, only seven components which are positive busbar and Z busbar are represented in this paper for using decision matrix methods.

  18. Synthesis and hydrophobic adsorption properties of microporous/mesoporous hybrid materials. (United States)

    Hu, Qin; Li, Jinjun; Qiao, Shizhang; Hao, Zhengping; Tian, Hua; Ma, Chunyan; He, Chi


    Hybrid materials of silicalite-1 (Sil-1)-coated SBA-15 particles (MSs) have been successfully synthesized by crystallization process under hydrothermal conditions. These MSs materials were characterized by X-ray diffraction, nitrogen adsorption/desorption and TEM techniques, which illustrated that the silicalite-1-coated SBA-15 particles were successfully prepared and had large pore volume and hierarchical pore size distribution. Further experimental studies indicated that longer crystallization time under basic condition caused the mesostructure of SBA-15 materials to collapse destructively and higher calcination temperature tended to disrupt the long-range mesoscopic order while they had little influence on the phase of microcrystalline silicalite-1 zeolite. The resultant MSs materials were investigated by estimating dynamic adsorption capacity under dry and wet conditions to evaluate their adsorptive and hydrophobic properties. The hydrophobicity index (HI) value followed the sequence of silicalite-1>MSs>SBA-15, which revealed that the SBA-15 particles coated with the silicalite-1 seeds enhanced the surface hydrophobicity, and also were consistent with FTIR results. Our studies show that MSs materials combined the advantages of the ordered mesoporous material (high adsorptive capacity, large pore volume) and silicalite-1 zeolite (super-hydrophobic property, high hydrothermal stability), and the presence of micropores directly led to an increase in the dynamic adsorption capacity of benzene under dry and wet conditions.

  19. Hydrophobic properties and chemical characterisation of natural water repellent materials in Australian sands (United States)

    Franco, C. M. M.; Clarke, P. J.; Tate, M. E.; Oades, J. M.


    Water-repellency in non-wetting sands is due to hydrophobic waxes present on the surface of sand grains and contained in particulate organic matter present in these sands. This study investigates the physico-chemical characteristics of these natural waxes and compares them to waxes extracted from potential original source materials. Non-polar and polar hydrophobic wax extracts were obtained from whole non-wetting sand, and its individual constituents, and associated organic matter. These included the sand fraction, the intrinsic particulate organic matter, tree litter, eucalyptus leaves, bark, lucerne and lupin plants, and fungi and actinomycetes isolated from these sands. Waxes were characterised for their hydrophobic properties and composition of their chemical constituents. The hydrophobicities of the waxes were assessed by measuring the water-repellency induced after treating acid washed sand with wax extracts. Non-polar and polar wax extracts of the tree litter displayed hydrophobic properties that were similar to the corresponding waxes isolated from non-wetting sand and intrinsic particulate organic matter. Unlike these plant-derived waxes, the microbial wax extracts possessed different hydrophobic properties. Characterisation of the components of the extracted waxes by gas chromatography-mass spectroscopy (GC-MS) analysis revealed a strong similarity in the composition of waxes isolated from non-wetting sand, tree litter and other plant material. The major components found were unbranched and branched C16 to C36 fatty acids and their esters, alkanes, phytanols, phytanes, and sterols. Some of these components were not detected in the microbial waxes. Unextracted samples, as well as wax extracts of non-wetting sand, intrinsic particulate organic matter, tree litter and fresh plant material were further analysed by solution and solid state Nuclear Magnetic Resonance spectroscopy which revealed the relative content of the different chemical species present.

  20. Dimensional Accuracy of Hydrophilic and Hydrophobic VPS Impression Materials Using Different Impression Techniques - An Invitro Study. (United States)

    Basapogu, Sreeramulu; Pilla, Ajai; Pathipaka, Suman


    The dimensional stability of the impression material could have an influence on the accuracy of the final restoration. Vinyl Polysiloxane Impression materials (VPS) are most frequently used as the impression material in fixed prosthodontics. As VPS is hydrophobic when it is poured with gypsum products, manufacturers added intrinsic surfactants and marketed as hydrophilic VPS. These hydrophilic VPS have shown increased wettability with gypsum slurries. VPS are available in different viscosities ranging from very low to very high for usage under different impression techniques. To compare the dimensional accuracy of hydrophilic VPS and hydrophobic VPS using monophase, one step and two step putty wash impression techniques. To test the dimensional accuracy of the impression materials a stainless steel die was fabricated as prescribed by ADA specification no. 19 for elastomeric impression materials. A total of 60 impressions were made. The materials were divided into two groups, Group1 hydrophilic VPS (Aquasil) and Group 2 hydrophobic VPS (Variotime). These were further divided into three subgroups A, B, C for monophase, one-step and two-step putty wash technique with 10 samples in each subgroup. The dimensional accuracy of the impressions was evaluated after 24 hours using vertical profile projector with lens magnification range of 20X-125X illumination. The study was analyzed through one-way ANOVA, post-hoc Tukey HSD test and unpaired t-test for mean comparison between groups. Results showed that the three different impression techniques (monophase, 1-step, 2-step putty wash techniques) did cause significant change in dimensional accuracy between hydrophilic VPS and hydrophobic VPS impression materials. One-way ANOVA disclosed, mean dimensional change and SD for hydrophilic VPS varied between 0.56% and 0.16%, which were low, suggesting hydrophilic VPS was satisfactory with all three impression techniques. However, mean dimensional change and SD for hydrophobic VPS

  1. Performance of a Novel Hydrophobic Mesoporous Material for High Temperature Catalytic Oxidation of Naphthalene

    Directory of Open Access Journals (Sweden)

    Guotao Zhao


    Full Text Available A high surface area, hydrophobic mesoporous material, MFS, has been successfully synthesized by a hydrothermal synthesis method using a perfluorinated surfactant, SURFLON S-386, as the single template. N2 adsorption and TEM were employed to characterize the pore structure and morphology of MFS. Static water adsorption test indicates that the hydrophobicity of MFS is significantly higher than that of MCM-41. XPS and Py-GC/MS analysis confirmed the existence of perfluoroalkyl groups in MFS which led to its high hydrophobicity. MFS was used as a support for CuO in experiments of catalytic combustion of naphthalene, where it showed a significant advantage over MCM-41 and ZSM-5. SEM was helpful in understanding why CuO-MFS performed so well in the catalytic combustion of naphthalene. Experimental results indicated that MFS was a suitable support for catalytic combustion of large molecular organic compounds, especially for some high temperature catalytic reactions when water vapor was present.

  2. Biodegradable packing materials from hydrolysates of collagen waste proteins. (United States)

    Langmaier, F; Mokrejs, P; Kolomaznik, K; Mladek, M


    Enzymatic hydrolysates of waste collagen proteins (H), from current industrial manufacture (leather, edible meat product casings, etc.) of mean molecular mass 20-30 kDa by a reaction with dialdehyde starch (DAS), produces hydrogels applicable as biodegradable (or even edible) packaging materials for food, cosmetic and pharmaceutical products. Thermo-reversibility of prepared hydrogels is given by concentrations of H and DAS in a reaction mixture. At concentrations of H 25-30% (w/w) and that of DAS 15-20% (related to weight of hydrolysate), thermo-reversible hydrogels arise, which can be processed into packaging materials by a technique similar to that of soft gelatin capsules (SGC). Exceeding the limit of 20% DAS leads to hydrogels that are thermo-reversible only in part, a further increase in DAS concentration then leads to thermo-irreversible gels whose processing into biodegradable packaging materials necessitates employment of other procedures.

  3. Treatability Variance Petition for SRS Raschig Ring Packing Material

    Energy Technology Data Exchange (ETDEWEB)

    Hagstrom, T.


    The Department of Energy's Savannah River Site (SRS) is a vital component in the nation's nuclear weapons complex. When in full operation, SRS produced nuclear material by manufacturing fuel and target components that were then irradiated in nuclear reactors.

  4. Development of anti-icing materials by chemical tailoring of hydrophobic textured metallic surfaces. (United States)

    Charpentier, Thibaut V J; Neville, Anne; Millner, Paul; Hewson, Rob W; Morina, Ardian


    Ice on surfaces can have dramatic consequences for human activities. Over the last decades, the design of new materials with anti-icing properties has generated significant research efforts for the prevention of ice accretion. Here we investigate water freezing temperatures on untreated and negatively charged hydrophobic stainless steel surfaces and use these temperatures to evaluate icephobicity. Supercooled water microdroplets are deposited and undergo a slow controlled cooling until spontaneous freezing occurs. Textured hydrophobic stainless steel surfaces functionalized with anionic polyelectrolytes brushes display unexpectedly lower freezing temperatures, at least 7 °C lower than polished untreated steel. On the basis of the entropy reduction of the crystalline phase near a charged solid surface, we used a modification of the classical heterogeneous nucleation theory to explain the observed freezing temperatures lessening. Our results could help the design of new composite materials that more efficiently prevent ice formation. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Polymer-coated fibrous materials as the stationary phase in packed capillary gas chromatography. (United States)

    Saito, Yoshihiro; Tahara, Ai; Imaizumi, Motohiro; Takeichi, Tsutomu; Wada, Hiroo; Jinno, Kiyokatsu


    Synthetic polymer filaments have been introduced as the support material in packed capillary gas chromatography (GC). The filaments of the heat-resistant polymers, Zylon, Kevlar, Nomex, and Technora, were longitudinally packed into a short fused-silica capillary, followed by the conventional coating process for open-tubular GC columns. The separation of several test mixtures such as n-alkylbenzenes and n-alkanes was carried out with these polymer-coated fiber-packed capillary columns. With the coating by various polymeric materials on the surface of these filaments, the retentivity was significantly improved over the parent fiber-packed column (without polymer coating) as well as a conventional open-tubular capillary of the same length. The results demonstrated a good combination of Zylon as the support and poly(dimethylsiloxane)-based materials as the coating liquid-phase for the successful GC separation of n-alkanes and polycyclic aromatic hydrocarbons (PAHs), while successful applications for other separations such as poly(ethylene glycol) coating for the separation of alcohols were also obtained. From the results it has been suggested that the selectivity of the fiber-packed column could be tuned by selecting different coating materials, indicating the promising possibility for a novel usage of fine fibrous polymers as the support material that can be combined with newly synthesized coating materials specially designed for particular separations. Taking advantage of good thermal stability of the fibers, the column temperature could be elevated to higher than 350 degrees C with the combination of a short metallic capillary.

  6. Influence of synthetic packing materials on the gas dispersion and biodegradation kinetics in fungal air biofilters

    NARCIS (Netherlands)

    Prenafeta-Boldú, F.X.; Illa, J.; Groenestijn, J.W. van; Flotats, X.


    The biodegradation of toluene was studied in two lab-scale air biofilters operated in parallel, packed respectively with perlite granules (PEG) and polyurethane foam cubes (PUC) and inoculated with the same toluene-degrading fungus. Differences on the material pore size, from micrometres in PEG to

  7. Numerical Model and Analysis of Peak Temperature Reduction in LiFePO4 Battery Packs Using Phase Change Materials

    DEFF Research Database (Denmark)

    Coman, Paul Tiberiu; Veje, Christian


    Numerical model and analysis of peak temperature reduction in LiFePO4 battery packs using phase change materials......Numerical model and analysis of peak temperature reduction in LiFePO4 battery packs using phase change materials...

  8. Antibacterial Activity of Hydrophobic Composite Materials Containing a Visible-Light-Sensitive Photocatalyst

    Directory of Open Access Journals (Sweden)

    Kentaro Yamauchi


    Full Text Available The conventional superhydrophobic surface offered by PTFE provides no sterilization performance and is not sufficiently repellent against organic liquids. These limit PTFE's application in the field of disinfection and result a lack of durability. N-doped TiO2 photocatalyst added PTFE composite material was developed to remedy these shortcomings. This paper reports the surface characteristics, and the bactericidal and self-cleaning performance of the newly-developed composite material. The material exhibited a contact angle exceeding 150 degrees consistent with its hydrophobicity despite the inclusion of the hydrophilic N-doped TiO2. The surface free energy obtained for this composite was 5.8 mN/m. Even when exposed to a weak fluorescent light intensity (100 lx for 24 hours, the viable cells of gram-negative E. coli on the 12% N-doped TiO2-PTFE film were reduced 5 logs. The higher bactericidal activity was also confirmed on the gram-positive MRSA. Compared with the N-doped TiO2 coating only, the inactivation rate of the composite material was significantly enhanced. Utilizing the N-doped TiO2 with the PTFE composite coating could successfully remove, by UV illumination, oleic acid adsorbed on its surface. These results demonstrate the potential applicability of the novel N-doped TiO2 photocatalyst hydrophobic composite material for both indoor antibacterial action and outdoor contamination prevention.

  9. Virtual modeling of polycrystalline structures of materials using particle packing algorithms and Laguerre cells (United States)

    Morfa, Carlos Recarey; Farias, Márcio Muniz de; Morales, Irvin Pablo Pérez; Navarra, Eugenio Oñate Ibañez de; Valera, Roberto Roselló


    The influence of the microstructural heterogeneities is an important topic in the study of materials. In the context of computational mechanics, it is therefore necessary to generate virtual materials that are statistically equivalent to the microstructure under study, and to connect that geometrical description to the different numerical methods. Herein, the authors present a procedure to model continuous solid polycrystalline materials, such as rocks and metals, preserving their representative statistical grain size distribution. The first phase of the procedure consists of segmenting an image of the material into adjacent polyhedral grains representing the individual crystals. This segmentation allows estimating the grain size distribution, which is used as the input for an advancing front sphere packing algorithm. Finally, Laguerre diagrams are calculated from the obtained sphere packings. The centers of the spheres give the centers of the Laguerre cells, and their radii determine the cells' weights. The cell sizes in the obtained Laguerre diagrams have a distribution similar to that of the grains obtained from the image segmentation. That is why those diagrams are a convenient model of the original crystalline structure. The above-outlined procedure has been used to model real polycrystalline metallic materials. The main difference with previously existing methods lies in the use of a better particle packing algorithm.

  10. Molecular organization of hydrophobic molecules and co-adsorbed water in SBA-15 ordered mesoporous silica material. (United States)

    Mellaerts, Randy; Roeffaers, Maarten B J; Houthoofd, Kristof; Van Speybroeck, Michiel; De Cremer, Gert; Jammaer, Jasper A G; Van den Mooter, Guy; Augustijns, Patrick; Hofkens, Johan; Martens, Johan A


    The purpose of this study was to improve our understanding of the molecular organization of hydrophobic guest molecules in the presence of co-adsorbed water inside SBA-15 ordered mesoporous silica material. Understanding this adsorption competition is essential in the development of applications of controlled adsorption and desorption. The poorly water soluble drug compound itraconazole and the fluorescent probe Nile red were selected for the study. The interaction between itraconazole and SBA-15 was investigated using FT-IR, (1)H MAS NMR and (29)Si MAS NMR spectroscopy, by determination of adsorption isotherms and release kinetics in simulated gastric fluid. The distribution and migration of the hydrophobic fluorescent probe Nile red was visualized in situ using confocal fluorescence microscopy. For both molecules, there was a pronounced influence of the co-adsorbed water on adsorption, hydrophobic aggregation and migration in SBA-15 pores. These insights contribute to the development of practical methods for loading ordered mesoporous silica materials with hydrophobic molecules.

  11. Synthesis of Hydrophobic Mesoporous Material MFS and Its Adsorption Properties of Water Vapor

    Directory of Open Access Journals (Sweden)

    Guotao Zhao


    Full Text Available Fluorine-containing hydrophobic mesoporous material (MFS with high surface area is successfully synthesized with hydrothermal synthesis method by using a perfluorinated surfactant SURFLON S-386 template. The adsorption properties of water vapor on the synthesized MFS are also investigated by using gravimetric method. Results show that SEM image of the MFS depicted roundish morphology with the average crystal size of 1-2 μm. The BET surface area and total pore volume of the MFS are 865.4 m2 g−1 and 0.74 cm3 g−1 with a narrow pore size distribution at 4.9 nm. The amount of water vapor on the MFS is about 0.41 mmol g−1 at 303 K, which is only 52.6% and 55.4% of MCM-41 and SBA-15 under the similar conditions, separately. The isosteric adsorption heat of water on the MFS is gradually about 27.0–19.8 kJ mol−1, which decreases as the absorbed water vapor amount increases. The value is much smaller than that on MCM-41 and SBA-15. Therefore, the MFS shows more hydrophobic surface properties than the MCM-41 and SBA-15. It may be a kind of good candidate for adsorption of large molecule and catalyst carrier with high moisture resistance.

  12. Analyze of Hydrophobic Characteristic of Surface Material Based on The Value of THD Leakage Current

    Directory of Open Access Journals (Sweden)

    Abdul Syakur


    Full Text Available Polymer material has been developed to replace the porcelain insulator material and glass. When it is used as outdoor insulator, environmental conditions have a significant influence to the value of surface discharge current, especially for the coastal area and industry. Salt, dust and chemicals contaminant are suspected as the causes of initial current of surface discharge and the insulator surface degradation which lead to a flashover. To analyze the performance of the insulator surface when the leakage current occurs, the Total Harmonic Distortion (THD is needed to be determined. The value of THD leakage current indicates the hydrophobic characteristic of surface material. This paper analyzes the results of leakage current measurement in laboratory-scale based on IEC 587:1986 with Inclined-Plane Tracking (IPT method to the High Density Polyethylene (HDPE polymer material which is provided in smooth and rough surface. The testing voltage is 50 Hz AC. Data of leakage current magnitude values cover its maximum average as a function of time and the result of FFT to the wave form of the leakage current. As the result, the value of percentage THD decrease as the function of time. The smooth surface material has THD value 43.42% and the rough surface has 15.89%.


    Directory of Open Access Journals (Sweden)

    I. Karpunin


    Full Text Available The paper reveals that while using magnesium bisulfite pulp cooking of raw material which serves for obtaining a desired product with its further application for packing making it is rather important that the raw material should contain hemicellulose and lignin. In the case when the content of hemicellulose  and lignin is rather high in the desired product its qualitative (physical and mechanical indices are deteriorating that negatively affects the qualitative values of the obtained packing.

  14. Performance evaluation of a slow-release packing material-embedded functional microorganisms for biofiltration. (United States)

    Zhu, Rencheng; Li, Shunyi; Wu, Zhenjun; Dumont, Éric


    A composite packing material (CM-5) was prepared in this study, mainly consisting of compost with functional microorganisms, calcium carbonate (CaCO3), perlite, cement and plant fiber. To get stronger compressive strength, mass ratios of these components were optimized based on single factor experiments, and finally adding amounts of perlite, cement, plant fiber, CaCO3, compost and binder at 18%, 18%, 7%, 13%, 17% and 27%, respectively. According to the optimum proportion, CM-5 was extruded in cylindrical shape (12 mm in diameter and 20 mm in length) with a bulk density of 470 kg m-3, a moisture retention capacity of 49% and the microbial counts of × 105 CFU g-1 of packing material. The cumulative release rates of total organic carbon (TOC) and total nitrogen (TN) from CM-5 were 3.1% and 6.5%, respectively, after 19 times extraction in distilled water. To evaluate the H2S removal capacity, CM-5 was compared with an organic (corncob) and an inorganic (ceramsite) packing material in three biofilters. The results showed that CM-5 had higher H2S removal capacity compared with corncob and ceramsite. CM-5 could avoid the large fluctuation of pH value and pressure drop during the operation. The maximum H2S removal capacity of CM-5 was 12.9 g m-3 h-1 and the removal efficiency could maintain over 95.4% when the inlet H2S loading rate was lower than 11.3 g m-3 h-1 without any addition of nutrients and pH buffer substances. Besides, only 2-3 days were needed for the recovery of biofiltration performance after about two weeks of idle period.

  15. Transparent Heat-Resistant PMMA Copolymers for Packing Light-Emitting Diode Materials

    Directory of Open Access Journals (Sweden)

    Shu-Ling Yeh


    Full Text Available Transparent and heat-resistant poly(methyl methacrylate copolymers were synthesized by bulk polymerizing methyl methacrylate (MMA, isobornyl methacrylate (IBMA, and methacrylamide (MAA monomers. Copolymerization was performed using a chain transfer agent to investigate the molecular weight changes of these copolymers, which exhibited advantages including a low molecular weight distribution, excellent optical properties, high transparency, high glass transition temperature, low moisture absorption, and pellets that can be readily mass produced by using extrusion or jet injection for packing light-emitting diode materials.


    Directory of Open Access Journals (Sweden)

    S. T. Antipov


    Full Text Available Summary. For increase of profitability of the food enterprises, decrease in an ecological trace from technogenic activity of the food industry the concept of development of low-waste and waste-free productions considered on the example of technology of receiving a biodegradable packing material from secondary material resources of food productions is offered: beer pellet, beet press, spirit bards, Pancake week press and bone glue. The technology of receiving biodegradable material from secondary material resources of food productions includes itself the following main stages: dehydration, crushing, mixing, leveling, formation, glazing. Advantage of the offered product consists of: - low cost of packing due to use of secondary material resources and full naturalness (now the raw materials for biodegradable packing specially are grown up on technical fields with use of GMO; - full decomposition in nature less than in 6 months according to GOST R 54533-2011 (EN 13432:2000 "Resource-saving. Packing. Requirements, criteria and the scheme of utilization of packing by means of a composting and biological decomposition"; - presence at the compost received at decomposition, the elements promoting increase of fertility of the soil. Application of technology allows reach at the same time three effects of a positive orientation: economic, ecological and social.

  17. Sorption of hydrophobic organic compounds to a diverse suite of carbonaceous materials with emphasis on biochar. (United States)

    Kupryianchyk, Darya; Hale, Sarah; Zimmerman, Andrew R; Harvey, Omar; Rutherford, David; Abiven, Samuel; Knicker, Heike; Schmidt, Hans-Peter; Rumpel, Cornelia; Cornelissen, Gerard


    Carbonaceous materials like biochars are increasingly recognized as effective sorbent materials for sequestering organic pollutants. Here, we study sorption behavior of two common hydrophobic organic contaminants 2,2',5,5'-tetrachlorobiphenyl (CB52) and phenanthrene (PHE), on biochars and other carbonaceous materials (CM) produced at a wide range of conditions and temperatures from various feedstocks. The primary aim was to establish structure-reactivity relationships responsible for the observed variation in CM and biochar sorption characteristics. CM were characterized for their elemental composition, surface area, pore size distribution, aromaticity and thermal stability. Freundlich sorption coefficients for CB52 and PHE (i.e. LogK(F,CB52) and K(F,PHE), respectively) to CM showed a variation of two to three orders of magnitude, with LogK(F,CB52) ranging from 5.12 ± 0.38 to 8.01 ± 0.18 and LogK(F,PHE) from 5.18 ± 0.09 to 7.42 ± 1.09. The highest LogK(F) values were observed for the activated CM, however, non-activated biochars produced at high temperatures (>700 °C) sorbed almost as strongly (within 0.2-0.5 Log units) as the activated ones. Sorption coefficients significantly increased with pyrolysis temperature, CM surface area and pore volume, aromaticity, and thermal stability, and decreased with H/C, O/C, (O + N)/C content. The results of our study contribute to the understanding of processes underlying HOC sorption to CM and explore the potential of CM as engineered sorbents for environmental applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. The role of condensed carbonaceous materials on the sorption of hydrophobic organic contaminants in subsurface sediments. (United States)

    Jeong, Sangjo; Wander, Michelle M; Kleineidam, Sybille; Grathwohl, Peter; Ligouis, Bertrand S; Werth, Charles J


    The identification and characterization of carbonaceous materials (CMs) that control hydrophobic organic chemical (HOC) sorption is essential to predict the fate and transport of HOCs in soils and sediments. The objectives of this paper are to determine the types of CMs that control HOC sorption in the oxidized and reduced zones of a glacially deposited groundwater sediment in central Illinois, with a special emphasis on the roles of kerogen and black carbon. After collection, the sediments were treated to obtain fractions of the sediment samples enriched in different types of CMs (e.g., humic acid, kerogen, black carbon), and selected fractions were subject to quantitative petrographic analysis. The original sediments and their enrichment fractions were evaluated for their ability to sorb trichloroethene (TCE), a common groundwater pollutant. Isotherm results and mass fractions of CM enrichments were used to calculate sorption contributions of different CMs. The results indicate that CMs in the heavy fractions dominate sorption because of their greater mass. Black carbon mass fractions of total CMs in the reduced sediments were calculated and used to estimate the sorption contribution of these materials. Results indicate that in the reduced sediments, black carbon may sequester as much as 32% of the sorbed TCE mass, butthat kerogen and humin are the dominant sorption environments. Organic carbon normalized sorption coefficients (K(oc)) were compared to literature values. Values for the central Illinois sediments are relatively large and in the range of values determined for materials high in kerogen and humin. This work demonstrates the advantage of using both sequential chemical treatment and petrographic analysis to analyze the sorption contributions of different CMs in natural soils and sediments, and the importance of sorption to natural geopolymers in groundwater sediments not impacted by anthropogenic sources of black carbon.

  19. Evaluation of low-cost materials for sorption of hydrophobic organic pollutants in stormwater. (United States)

    Björklund, Karin; Li, Loretta


    Conventional stormwater treatment techniques such as sedimentation and filtration are inefficient for removing the dissolved and colloidal phases of hydrophobic organic compounds (HOCs) present in stormwater. Adsorption could be a promising technique for removing colloidal and dissolved pollutants. Five low-cost sorbent materials were investigated in this project, including two minerals – vermiculite and perlite – and three waste products – two pine barks and a sawdust – as potential adsorbents for removal of polycyclic aromatic hydrocarbons (PAHs), alkylphenols and phthalates; HOCs commonly found in stormwater. Adsorption capacity and kinetics were studied through batch adsorption tests using synthetic stormwater spiked with a mixture of HOCs. Vermiculite and perlite exhibited insignificant removal of the organic contaminants. The three wood-based materials retained >80% of the initial HOC concentration (10-300 μg/L). The two barks exhibited slightly higher adsorption capacities of HOCs than the sawdust. For all compounds tested, maximum adsorption onto the wood-based media was reached in <10 min. The highest adsorption capacity was found for PAHs (up to 45 μg/g), followed by alkylphenols and phthalates. No correlation was found between adsorption capacity and physical-chemical parameters such as solubility and partition coefficients (log K(ow)). Agreement between empirical data and the pseudo-second order kinetic model suggest chemisorption of HOCs onto a monolayer on wood-based media. This could lead to early saturation of the materials and should be investigated in future studies through repeated adsorption of HOCs, for example in column studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Investigation of surface properties of soil particles and model materials with contrasting hydrophobicity using atomic force microscopy. (United States)

    Cheng, Shuying; Bryant, Robert; Doerr, Stefan H; Wright, Christopher I; Williams, P Rhodri


    Surface images and force measurements obtained using atomic force microscopy (AFM) were used to assess the hydrophobicity of particles from soils and model soil material (smooth glass and acid-washed sand (AWS) exposed to soil-derived humic acid (HA) or lecithin (LE)). Height and phase images, and phase distributions (from soil particles) show complex morphology and heterogeneously distributed organic matter. Forces at model surfaces indicate that, in air, reduction in adhesion corresponded with increased hydrophobicity, but in water, corresponded with a decrease (and serve to guide interpretation of data from natural particles). Adhesion forces on hydrophobic soil particles in water were larger than those for hydrophilic ones, but surface roughness and complexity may obscure any opposite trend for measurements in air. Combination of force measurements, applied forthe first time to soil particles, together with those on model surfaces, and independent assessments of hydrophobicity of corresponding single particle layers, indicate good, but not consistent qualitative agreement between hydophobicity at bulk and nanoscales. AFM is likely to facilitate detailed evaluation of soil particle surface hydrophobicity, which contributes to bulk wetting behavior of soils and other porous systems, including assessments of the potential for contributons to supehydrophobicity from surfaces at the micro- and nanoscales.

  1. Preventing thermal runaway propagation in lithium ion battery packs using a phase change composite material: An experimental study (United States)

    Wilke, Stephen; Schweitzer, Ben; Khateeb, Siddique; Al-Hallaj, Said


    The safety issues of lithium ion batteries pose ongoing challenges as the market for Li-ion technology continues to grow in personal electronics, electric mobility, and stationary energy storage. The severe risks posed by battery thermal runaway necessitate safeguards at every design level - from materials, to cell construction, to module and pack assembly. One promising approach to pack thermal management is the use of phase change composite materials (PCC™), which offer passive protection at low weight and cost while minimizing system complexity. We present experimental nail penetration studies on a Li-ion pack for small electric vehicles, designed with and without PCC, to investigate the effectiveness of PCC thermal management for preventing propagation when a single cell enters thermal runaway. The results show that when parallel cells short-circuit through the penetrated cell, the packs without PCC propagate fully while those equipped with PCC show no propagation. In cases where no external short circuits occur, packs without PCC sometimes propagate, but not consistently. In all test conditions, the use of PCC lowers the maximum temperature experienced by neighboring cells by 60 °C or more. We also elucidate the propagation sequence and aspects of pack failure based on cell temperature, voltage, and post-mortem data.

  2. Biosorption of copper by marine algae Gelidium and algal composite material in a packed bed column. (United States)

    Vilar, Vítor J P; Botelho, Cidália M S; Loureiro, José M; Boaventura, Rui A R


    Marine algae Gelidium and algal composite material were investigated for the continuous removal of Cu(II) from aqueous solution in a packed bed column. The biosorption behaviour was studied during one sorption-desorption cycle of Cu(II) in the flow through column fed with 50 and 25 mg l(-1) of Cu(II) in aqueous solution, at pH 5.3, leading to a maximum uptake capacity of approximately 13 and 3 mg g(-1), respectively, for algae Gelidium and composite material. The breakthrough time decreases as the inlet copper concentration increases, for the same flow rate. The pH of the effluent decreases over the breakthrough time of copper ions, which indicates that ion exchange is one of the mechanisms involved in the biosorption process. Temperature has little influence on the metal uptake capacity and the increase of the ionic strength reduces the sorption capacity, decreasing the breakthrough time. Desorption using 0.1M HNO(3) solution was 100% effective. After two consecutive sorption-desorption cycles no changes in the uptake capacity of the composite material were observed. A mass transfer model including film and intraparticle resistances, and the equilibrium relationship, for adsorption and desorption, was successfully applied for the simulation of the biosorption column performance.

  3. Surface Characterization of Some Novel Bonded Phase Packing Materials for HPLC Columns Using MAS-NMR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Jude Abia


    Full Text Available Information on the surface properties of three novel chemically bonded phase packing materials for High performance liquid chromatography (HPLC were obtained using spectra obtained by solid state cross-polarization (CP magic-angle spinning (MAS nuclear magnetic resonance (NMR spectroscopic experiments for the 29Si, and 13C nuclei. These packing materials were: Cogent bidentate C18 bonded to type-C silica, hybrid packing materials XTerra MS C18, and XBridge Prep. C18. The spectra obtained using cross-polarization magic angle spinning (CP-MAS on the Cogent bidentate C18 bonded to type-C silica show the surface to be densely populated with hydride groups (Si-H, with a relative surface coverage exceeding 80%. The hybrid packing materials XTerra and XBridge gave spectra that reveal the silicon atoms to be bonded to organic moieties embedded in the molecular structure of these materials with over 90% of the alkyl silicon atoms found within the completely condensed silicon environments. The hydrolytic stability of these materials were investigated in acidic aqueous solutions at pHs of 7.0 and 3.0, and it was found that while the samples of XTerra and XBridge were not affected by hydrolysis at this pH range, the sample of Cogent lost a significant proportion of its Si-H groups after five days of treatment in acidic aqueous solution.

  4. Influence of synthetic packing materials on the gas dispersion and biodegradation kinetics in fungal air biofilters

    Energy Technology Data Exchange (ETDEWEB)

    Prenafeta-Boldu, F.X. [GIRO Technological Centre, Mollet del Valles, Barcelona (Spain); IRTA, Barcelona (Spain); Illa, J. [Lleida Univ. (Spain); Groenestijn, J.W. van [TNO, Zeist (Netherlands). Dept. of Microbiology; Flotats, X. [GIRO Technological Centre, Mollet del Valles, Barcelona (Spain); Lleida Univ. (Spain)


    The biodegradation of toluene was studied in two lab-scale air biofilters operated in parallel, packed respectively with perlite granules (PEG) and polyurethane foam cubes (PUC) and inoculated with the same toluene-degrading fungus. Differences on the material pore size, from micrometres in PEG to millimetres in PUC, were responsible for distinct biomass growth patterns. A compact biofilm was formed around PEG, being the interstitial spaces progressively filled with biomass. Microbial growth concentrated at the core of PUC and the excess of biomass was washed-off, remaining the gas pressure drop comparatively low. Air dispersion in the bed was characterised by tracer studies and modelled as a series of completely stirred tanks (CSTR). The obtained number of CSTR (n) in the PEG packing increased from 33 to 86 along with the applied gas flow (equivalent to empty bed retention times from 48 to 12 s) and with operation time (up to 6 months). In the PUC bed, n varied between 9 and 13, indicating that a stronger and steadier gas dispersion was achieved. Michaelis-Menten half saturation constant (k{sub m}) estimates ranged 71-113 mg m{sup -3}, depending on the experimental conditions, but such differences were not significant at a 95% confidence interval. The maximum volumetric elimination rate (r{sub m}) varied from 23 to 50 g m{sup -3} h{sup -1}. Comparison between volumetric and biomass specific biodegradation activities indicated that toluene mass transfer was slower with PEG than with PUC as a consequence of a smaller biofilm surface and to the presence of larger zones of stagnant air. (orig.)

  5. 49 CFR 173.226 - Materials poisonous by inhalation, Division 6.1, Packing Group I, Hazard Zone A. (United States)


    ... packaging system. The inner packaging system consists of two packagings: (i) an impact-resistant receptacle... MATERIALS REGULATIONS SHIPPERS-GENERAL REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS Non-bulk Packaging for....133) must be packed in non-bulk packagings in accordance with the following paragraphs: (a) In...

  6. Parameters for scale-up of lethal microwave treatment to eradicate cerambycid larvae infesting solid wood packing materials (United States)

    Mary R. Fleming; John J. Janowiak; Joseph Kearns; Jeffrey E. Shield; Rustum Roy; Dinesh K. Agrawal; Leah S. Bauer; Deborah L. Miller; Kelli Hoover


    The use of microwave irradiation to eradicate insects infesting wood used to manufacture packing materials such as pallets and crateswas evaluated. The focus of this preliminary studywas to determinewhich microwave parameters, including chamber-volume to sample-volumeratios,variations ofpower and time, and energydensity (total microwavepower/woodvolume), affect the...

  7. Conversion of hydrophilic SiOC nanofibrous membrane to robust hydrophobic materials by introducing palladium (United States)

    Wu, Nan; Wan, Lynn Yuqin; Wang, Yingde; Ko, Frank


    Hydrophobic ceramic nanofibrous membranes have wide applications in the fields of high-temperature filters, oil/water separators, catalyst supports and membrane reactors, for their water repellency property, self-cleaning capability, good environmental stability and long life span. In this work, we fabricated an inherently hydrophobic ceramic nanofiber membrane without any surface modification through pyrolysis of electrospun polycarbosilane nanofibers. The hydrophobicity was introduced by the hierarchical microstructure formed on the surface of the nanofibers and the special surface composition by the addition of trace amounts of palladium. Furthermore, the flexible ceramic mats demonstrated robust chemical resistance properties with consistent hydrophobicity over the entire pH value range and effective water-in-oil emulsion separation performance. Interestingly, a highly cohesive force was found between water droplet and the ceramic membranes, suggesting their great potentials in micro-liquid transportation. This work provides a new route for adjusting the composition of ceramic surface and flexible, recyclable and multifunctional ceramic fibrous membranes for utilization in harsh environments.

  8. Middle ear packing materials: comparison between absorbable hemostatic gelatine sponge and sugarcane biopolymer sponge in rats

    Directory of Open Access Journals (Sweden)

    Débora Lopes Bunzen


    Full Text Available INTRODUCTION: Several biomaterials can be used in ear surgery to pack the middle ear or support the graft. The absorbable gelatin sponge is the most widely used, but it may produce fibrosis and impair ventilation of the middle ear. OBJECTIVE: This experimental study aimed to investigate the inflammatory effects of the sugarcane biopolymer sponge (BP in the rat middle ear compared with absorbable gelatin sponge (AGS. MATERIALS AND METHODS: Prospective experimental study design. Thirty adult female Wistar rats were allocated to receive the BP sponge into the right ear and AGS into the left ear. Animals were randomly killed at 4 and 12 weeks post-procedure. Qualitative histological assessments were performed to evaluate the inflammatory reaction in the tympanic bullae. RESULTS: The BP sponge caused inflammation more intense and persistent than AGS. The BP was not absorbed during the experiment. Fibrosis was observed only in the ears with AGS. There were thickening of the mucosa and neoangiogenesis in the group of AGS. CONCLUSION: Despite inflammation, the BP sponge produced less fibrosis and neoangiogenesis compared to AGS. The sponge BP appeared to be a non-absorbable biomaterial in the middle ear.


    Directory of Open Access Journals (Sweden)



    Full Text Available The effect of storage duration on fungal population, moisture content, lipid and free fatty acid contents, lipase activity, viability and vigor of physic nut seeds was investigated. Physic nut seeds with initial moisture content of 7.9% were stored in plastic bags under warehouse conditions. Samples of physic nut were collected before storage, and subsequently after one to six months of storage. The results showed that the moisture contents increased after one month of storage, and became relatively constant up to six months of storage. The range of moisture contents (7.9 – 8.4% was safe for storage of physic nut seeds. Sixteen fungal species were isolated from physic nut seeds during six months of storage. Fungal population decreased with the increase of storage duration. At the beginning of storage, most of the fungi that infected the seeds were classified as field fungi, such as Colletotrichum sp., Cladosporium spp., and Fusarium spp.. Their populations decreased with the increase of storage duration. After three months of storage, the existence of field fungi was generally replaced by storage fungi, such as Aspergillus spp., and Penicillium spp . dominate the population. Lipid contents, viabilities and vigors decreased with the increase of storage duration, while free fatty acids and lipase activities increased. Under uncontrolled condi -tions, physic nut seeds packed in plastic material can be stored up to one month for seeds to be planted, while it can be stored up to five months for producing oil.

  10. Sulfuryl fluoride as a quarantine treatment for Anoplophora glabripennis (Coleoptera: Cerambycidae) in regulated wood packing material. (United States)

    Barak, A V; Wang, Y; Zhan, G; Wu, Y; Xu, L; Huang, Q


    The Asian longhorned beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), was probably introduced into the United States from China with solid wood packing and dunnage during the 1980s, and it has recently become established in limited infestations near several major cities in the United States. Regulated wood packing material (RWPM) arriving in the United States from China is required to undergo fumigation with methyl bromide (MeBr), to be heat treated, or kiln dried. Sulfuryl fluoride (SF) is a candidate fumigant to replace MeBr under certain conditions. SF fumigations were conducted in 432-liter Lexan chambers held in a 6.1-m (20-foot) refrigerated container for temperature control. Each fumigation consisted of 12 Populus spp. 10- by 10- by 115-cm timbers, of high moisture content, naturally infested with Asian longhorned beetle. During 2001, we fumigated wood for 24 h at a range of doses (20-112 g/m3) and temperatures (4.4, 10.0, 15.6, and 21.1 degrees C) and subjected the data to probit analysis. Confirmatory fumigations were conducted at doses of 120 and 104 g/m3 at temperatures of 10.0 and 15.6 or 21.1 degrees C, respectively, which resulted in complete kill of all larvae. Pupae that became available later in the year as temperatures warmed were fumigated at 15.6 and 21.1 degrees C with 104 g/m3, which resulted in complete pupal mortality. The next year (2002), we conducted 24-h fumigations with doses of 116 g/m3 at 4.4 and 10.0 degrees C with cold-harvested wood infested with cold-acclimated larvae. Cold-acclimated larvae required much higher concentration times time (CxT) product for control at 4.4 and 10.0 degrees C compared with nonacclimated larvae. Sulfuryl fluoride treatments at a dose of 104 g/m3 and temperature of 15.6 degrees C and above and that achieved a CxT product of 1,095 g-h/m3 or above are recommended for RWPM infested with Asian longhorned beetle larvae and pupae.

  11. Micelle swelling agent derived cavities for increasing hydrophobic organic compound removal efficiency by mesoporous micelle@silica hybrid materials

    KAUST Repository

    Shi, Yifeng


    Mesoporous micelle@silica hybrid materials with 2D hexagonal mesostructures were synthesized as reusable sorbents for hydrophobic organic compounds (HOCs) removal by a facile one-step aqueous solution synthesis using 3-(trimethoxysily)propyl-octadecyldimethyl-ammonium chloride (TPODAC) as a structure directing agent. The mesopores were generated by adding micelle swelling agent, 1,3,5-trimethyl benzene, during the synthesis and removing it afterward, which was demonstrated to greatly increase the HOC removal efficiency. In this material, TPODAC surfactant is directly anchored on the pore surface of mesoporous silica via SiOSi covalent bond after the synthesis due to its reactive Si(OCH 3) 3 head group, and thus makes the synthesized materials can be easily regenerated for reuse. The obtained materials show great potential in water treatment as pollutants sorbents. © 2011 Elsevier Inc. All rights reserved.

  12. Submicron and Nanoparticulate Matter Removal by HEPA-Rated Media Filters and Packed Beds of Granular Materials (United States)

    Perry, J. L.; Agui, J. H.; Vijayakimar, R


    Contaminants generated aboard crewed spacecraft by diverse sources consist of both gaseous chemical contaminants and particulate matter. Both HEPA media filters and packed beds of granular material, such as activated carbon, which are both commonly employed for cabin atmosphere purification purposes have efficacy for removing nanoparticulate contaminants from the cabin atmosphere. The phenomena associated with particulate matter removal by HEPA media filters and packed beds of granular material are reviewed relative to their efficacy for removing fine (less than 2.5 micrometers) and ultrafine (less than 0.01 micrometers) sized particulate matter. Considerations are discussed for using these methods in an appropriate configuration to provide the most effective performance for a broad range of particle sizes including nanoparticulates.

  13. Graphite intercalated polyaniline composite with superior anticorrosive and hydrophobic properties, as protective coating material on steel surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rathnayake, R.M.N.M. [National Institute of Fundamental Studies, Kandy (Sri Lanka); Graduate School of Engineering, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya 468-8511 (Japan); Mantilaka, M.M.M.G.P.G. [Sri Lanka Institute of Nanotechnology, Nanotechnology and Science Park, Mahenwatte, Pitipana, Homagama (Sri Lanka); Hara, Masanori; Huang, Hsin-Hui [Graduate School of Engineering, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya 468-8511 (Japan); Wijayasinghe, H.W.M.A.C., E-mail: [National Institute of Fundamental Studies, Kandy (Sri Lanka); Yoshimura, Masamichi [Graduate School of Engineering, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya 468-8511 (Japan); Pitawala, H.M.T.G.A. [Department of Geology, University of Peradeniya, Peradeniya (Sri Lanka)


    Highlights: • In this paper, it has been utilized a novel method to prepare a new composite material of PANI/NPG graphite composite, using NPG vein graphite variety. • It is found that the composite works as an anti-corrosive coating on steel surfaces. Further, the prepared composite shows good hydrophobic ability, which is very useful in preventing corrosion on metal surfaces. • The prepared PANI/NPG composite material shows a significantly high corrosion resistance compared to alkyd resin/PANI coatings or alkyd resin coatings, on steel surfaces. - Abstract: Solid polymer composite systems are widely being used for potential technological applications in secondary energy sources and electrochromic devices. In this study, we synthesized and characterized a composite material composed of polyaniline (PANI) and natural needle platy (NPG) vein graphite. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), cyclic voltammetry (CV), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), micro-Raman analysis, thermogravimetric and differential thermal analysis (TGA/DTA), transmission electron microscopy (TEM) were used to study the structural and electrochemical properties of the prepared PANI/NPG graphite composite. XPS, FTIR, and micro-Raman analysis confirmed the existence of relevant functional groups and bonding in the prepared PANI/NPG composite material. The composite shows a very low corrosion rate, approximately 29 μm per year, and high hydrophobicity on steel surfaces, which helps to prevent the corrosion due to O{sub 2} penetration towards the metal surface. It indicates that the composite can be used as a high potential surface coating material to anticorrosion. The specific capacitance of PANI/NPG composite is 833.3 F g{sup −1}, which is higher than that of PANI. This synergistic electrical performance result proves the prepared PANI/NPG graphite composite as a suitable protective coating material for steel

  14. The vitamin C content of orange juice packed in an oxygen scavenger material

    NARCIS (Netherlands)

    Zerdin, K.; Rooney, M.L.; Vermuë, J.


    A storage study of orange juice packed in oxygen scavenging (OS) film and oxygen barrier film was conducted to determine the extent of ascorbic acid loss due to oxygen as a function of time and temperature. The initial concentration of ascorbic acid in the orange juice was 374 mg/l and this was

  15. Packing in protein cores (United States)

    Gaines, J. C.; Clark, A. H.; Regan, L.; O'Hern, C. S.


    Proteins are biological polymers that underlie all cellular functions. The first high-resolution protein structures were determined by x-ray crystallography in the 1960s. Since then, there has been continued interest in understanding and predicting protein structure and stability. It is well-established that a large contribution to protein stability originates from the sequestration from solvent of hydrophobic residues in the protein core. How are such hydrophobic residues arranged in the core; how can one best model the packing of these residues, and are residues loosely packed with multiple allowed side chain conformations or densely packed with a single allowed side chain conformation? Here we show that to properly model the packing of residues in protein cores it is essential that amino acids are represented by appropriately calibrated atom sizes, and that hydrogen atoms are explicitly included. We show that protein cores possess a packing fraction of φ ≈ 0.56 , which is significantly less than the typically quoted value of 0.74 obtained using the extended atom representation. We also compare the results for the packing of amino acids in protein cores to results obtained for jammed packings from discrete element simulations of spheres, elongated particles, and composite particles with bumpy surfaces. We show that amino acids in protein cores pack as densely as disordered jammed packings of particles with similar values for the aspect ratio and bumpiness as found for amino acids. Knowing the structural properties of protein cores is of both fundamental and practical importance. Practically, it enables the assessment of changes in the structure and stability of proteins arising from amino acid mutations (such as those identified as a result of the massive human genome sequencing efforts) and the design of new folded, stable proteins and protein-protein interactions with tunable specificity and affinity.

  16. Hydrophobic modification of polymethyl methacrylate as intraocular lenses material to improve the cytocompatibility. (United States)

    Wang, Bailiang; Lin, Quankui; Shen, Chenghui; Tang, Junmei; Han, Yuemei; Chen, Hao


    The development of posterior capsule opacification (PCO) after intraocular lenses (IOL) implantation for dealing with cataract is mainly due to the severe loss of the human lens epithelial cells (HLECs) during surgery contact. A novel poly (hedral oligomeric silsesquioxane-co-methyl methacrylate) copolymer (allyl POSS-PMMA) was synthesized by free radical polymerization method to promote the adhesion of HLECs. FT-IR and (1)H NMR measurements indicated the existence of POSS cage in the product, which demonstrated the successful synthesis of allyl POSS-PMMA copolymer. Effect of allyl POSS in the hybrids on crystal structure, surface wettability and morphology, optical transmission, thermodynamic properties and cytocompatibility was investigated in detail. X-ray diffraction peaks at 2θ∼11° and 12° indicated that POSS molecules had aggregated and crystallized. Thermogravimetric analysis-differential scanning calorimeter and optical transmission measurements confirmed that the allyl POSS-PMMA copolymer had high glass transition temperatures (more than 100°C) and good transparency. The hydrophilicity and morphology of PMMA and copolymers surfaces were characterized by static water contact angle and atomic force microscopy. The results revealed that the surface of the allyl POSS-PMMA copolymer displayed higher hydrophobicity and higher roughness than that of pure PMMA. The surface biocompatibility was evaluated by morphology and activity measurement with HLECs in vitro. The results verified that the surface of allyl POSS-PMMA copolymer films had more HLECs adhesion and better spreading morphology than that of PMMA film. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Graphite intercalated polyaniline composite with superior anticorrosive and hydrophobic properties, as protective coating material on steel surfaces (United States)

    Rathnayake, R. M. N. M.; Mantilaka, M. M. M. G. P. G.; Hara, Masanori; Huang, Hsin-Hui; Wijayasinghe, H. W. M. A. C.; Yoshimura, Masamichi; Pitawala, H. M. T. G. A.


    Solid polymer composite systems are widely being used for potential technological applications in secondary energy sources and electrochromic devices. In this study, we synthesized and characterized a composite material composed of polyaniline (PANI) and natural needle platy (NPG) vein graphite. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), cyclic voltammetry (CV), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), micro-Raman analysis, thermogravimetric and differential thermal analysis (TGA/DTA), transmission electron microscopy (TEM) were used to study the structural and electrochemical properties of the prepared PANI/NPG graphite composite. XPS, FTIR, and micro-Raman analysis confirmed the existence of relevant functional groups and bonding in the prepared PANI/NPG composite material. The composite shows a very low corrosion rate, approximately 29 μm per year, and high hydrophobicity on steel surfaces, which helps to prevent the corrosion due to O2 penetration towards the metal surface. It indicates that the composite can be used as a high potential surface coating material to anticorrosion. The specific capacitance of PANI/NPG composite is 833.3 F g-1, which is higher than that of PANI. This synergistic electrical performance result proves the prepared PANI/NPG graphite composite as a suitable protective coating material for steel surfaces.

  18. Modeling a material from packing, through sintering and to the final microstructural properties

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Nielsen, Kaspar Kirstein

    and magnetism known as the magnetocaloric effect. We present a 3-dimensional time-dependent numerical model that spatially resolves samples down to the grain size, and includes the demagnetizing field, chemical inhomogeneity realized as a spatial variation of Curie temperature across the sample, local...... hysteresis and heat transfer. We can thus model how particle size, packing, sintering and chemical inhomogeneity affect the observed properties of magnetocaloric samples. For example, we show that even a modest distribution in Curie temperature (TC) across the sample results in a significant broadening...... and lowering of the total entropy change of the sample around TC. We discuss how clustering of grains with similar values of TC across the sample influences the results....

  19. Electrochemical synthesis of hexagonal closed pack nickel: A hydrogen storage material

    Energy Technology Data Exchange (ETDEWEB)

    Lahiri, Abhishek; Das, Rupak; Reddy, Ramana G. [Department of Metallurgical and Material Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States)


    An in situ hydrogen generation and storage technique is demonstrated during the electrodeposition of hexagonal closed pack (HCP) nickel from NiCl{sub 2}-1-ethyl-3-methylimidazolium chloride (NiCl{sub 2}-EmimCl) and NiCl{sub 2}.6H{sub 2}O-1-ethyl-3-methylimidazolium chloride (NiCl{sub 2}.6H{sub 2}O-EmimCl) melts. During electrolysis, the dissolution of hydrogen in nickel takes place due to the electrolysis of water. This results in the production of HCP nickel. The hydrogen content of the electrodeposited nickel from NiCl{sub 2}-EmimCl was found to be 1.2 wt.%. Thermal analysis showed that the phase transformation from HCP nickel to FCC occurred at 462 C, releasing hydrogen in the process. (author)

  20. Relationship between Surface Properties and In Vitro Drug Release from Compressed Matrix Containing Polymeric Materials with Different Hydrophobicity Degrees

    Directory of Open Access Journals (Sweden)

    Cristhian J. Yarce


    Full Text Available This work is the continuation of a study focused on establishing relations between surface thermodynamic properties and in vitro release mechanisms using a model drug (ampicillin trihydrate, besides analyzing the granulometric properties of new polymeric materials and thus establishing the potential to be used in the pharmaceutical field as modified delivery excipients. To do this, we used copolymeric materials derived from maleic anhydride with decreasing polarity corresponding to poly(isobutylene-alt-maleic acid (hydrophilic, sodium salt of poly(maleic acid-alt-octadecene (amphiphilic, poly(maleic anhydride-alt-octadecene (hydrophobic and the reference polymer hydroxyl-propyl-methyl-cellulose (HPMC. Each material alone and in blends underwent spectroscopic characterization by FTIR, thermal characterization by DSC and granulometric characterization using flow and compaction tests. Each tablet was prepared at different polymer ratios of 0%, 10%, 20%, 30% and 40%, and the surface properties were determined, including the roughness by micro-visualization, contact angle and water absorption rate by the sessile drop method and obtaining Wadh and surface free energy (SFE using the semi-empirical models of Young–Dupré and  Owens-Wendt-Rabel-Käelbe (OWRK, respectively. Dissolution profiles were determined simulating physiological conditions in vitro, where the kinetic models of order-zero, order-one, Higuchi and Korsmeyer–Peppas were evaluated. The results showed a strong relationship between the proportion and nature of the polymer to the surface thermodynamic properties and kinetic release mechanism.

  1. Relationship between Surface Properties and In Vitro Drug Release from Compressed Matrix Containing Polymeric Materials with Different Hydrophobicity Degrees. (United States)

    Yarce, Cristhian J; Echeverri, Juan D; Palacio, Mario A; Rivera, Carlos A; Salamanca, Constain H


    This work is the continuation of a study focused on establishing relations between surface thermodynamic properties and in vitro release mechanisms using a model drug (ampicillin trihydrate), besides analyzing the granulometric properties of new polymeric materials and thus establishing the potential to be used in the pharmaceutical field as modified delivery excipients. To do this, we used copolymeric materials derived from maleic anhydride with decreasing polarity corresponding to poly(isobutylene-alt-maleic acid) (hydrophilic), sodium salt of poly(maleic acid-alt-octadecene) (amphiphilic), poly(maleic anhydride-alt-octadecene) (hydrophobic) and the reference polymer hydroxyl-propyl-methyl-cellulose (HPMC). Each material alone and in blends underwent spectroscopic characterization by FTIR, thermal characterization by DSC and granulometric characterization using flow and compaction tests. Each tablet was prepared at different polymer ratios of 0%, 10%, 20%, 30% and 40%, and the surface properties were determined, including the roughness by micro-visualization, contact angle and water absorption rate by the sessile drop method and obtaining Wadh and surface free energy (SFE) using the semi-empirical models of Young-Dupré and  Owens-Wendt-Rabel-Käelbe (OWRK), respectively. Dissolution profiles were determined simulating physiological conditions in vitro, where the kinetic models of order-zero, order-one, Higuchi and Korsmeyer-Peppas were evaluated. The results showed a strong relationship between the proportion and nature of the polymer to the surface thermodynamic properties and kinetic release mechanism.

  2. Teflon-carbon black as new material for the hydrophobic patterning of polymer labs-on-a-chip


    Mielnik, Michal Marek


    We provide a new method for the selective surface patterning of microfluidic chips with hydrophobic fluoropolymers which is demonstrated by the fabrication of hydrophobic valves. It enables efficient optical quality control for the surface patterning thus permitting the lowcost production of highly reproducible hydrophobic valves. Specifically, a fluoropolymer-solvent-dye solution based on carbon black (CB) is presented which creates superhydrophobic surfaces (contact angle = 157.9°) onchips ...

  3. Noncovalent Intermolecular Interactions in Organic Electronic Materials: Implications for the Molecular Packing vs Electronic Properties of Acenes

    KAUST Repository

    Sutton, Christopher


    Noncovalent intermolecular interactions, which can be tuned through the toolbox of synthetic chemistry, determine not only the molecular packing but also the resulting electronic, optical, and mechanical properties of materials derived from π-conjugated molecules, oligomers, and polymers. Here, we provide an overview of the theoretical underpinnings of noncovalent intermolecular interactions and briefly discuss the computational chemistry approaches used to understand the magnitude of these interactions. These methodologies are then exploited to illustrate how noncovalent intermolecular interactions impact important electronic properties-such as the electronic coupling between adjacent molecules, a key parameter for charge-carrier transport-through a comparison between the prototype organic semiconductor pentacene with a series of N-substituted heteropentacenes. Incorporating an understanding of these interactions into the design of organic semiconductors can assist in developing novel materials systems from this fascinating molecular class. © 2015 American Chemical Society.

  4. Support material dictates the attached biomass characteristics during the immobilization process in anaerobic continuous-flow packed-bed bioreactor. (United States)

    Kerčmar, Jasmina; Pintar, Albin


    Hydrogen is considered to be an ideal energy alternative to replace environmentally burdensome fossil fuels. For its long-term production the immobilized biofilm system is the most promising and to choose the right support material the most challenging. In this respect, the anaerobic up-flow bioreactors packed with four most used support materials (polyethylene, polyurethane, activated carbon and expanded clay) were tested to investigate the crucial bacteria sensitive period-the immobilization process. Seven-day-operation was necessary and sufficient to reach metabolic and microbial stability regardless of support material used. The support material had an influence on the microbial metabolic activity as well as on quantity and quality characteristics of the immobilized microbial community, being polyethylene and expanded clay more appropriate as supports among the materials evaluated; this could be attributed to pH alteration. The obtained results suggest that the support material dictates the outcome of the immobilization process in the anaerobic continuous-flow bioreactor. Copyright © 2017. Published by Elsevier Ltd.

  5. Washable hydrophobic smart textiles and multi-material fibers for wireless communication (United States)

    Gorgutsa, Stepan; Bachus, Kyle; LaRochelle, Sophie; Oleschuk, Richard D.; Messaddeq, Younes


    This paper reports on the performance and environmental endurance of the recently presented wirelessly communicating smart textiles with integrated multi-material fiber antennas. Metal–glass–polymer fiber composites were fabricated using sub-1 mm hollow-core silica fibers and liquid state silver deposition technique. These fibers were then integrated into textiles in the form of center-fed dipole and loop antennas during standard weaving procedure. Fiber antennas performance was found to be directly comparable to classic ‘rigid’ solutions in terms of return loss, gain and radiation patterns, which allowed transmitting data through Bluetooth protocol at 2.4 GHz frequency. Applied superhydrophobic coatings (water contact angle = 152°, sliding angle = 6°) allow uninterrupted wireless communication of the textiles under direct water application even after multiple washing cycles.

  6. Effect of different tetra pack juices on microhardness of direct tooth colored-restorative materials. (United States)

    Fatima, Nazish; Abidi, Syed Yawar Ali; Qazi, Fazal-Ur-Rehaman; Jat, Shahbaz Ahmed


    To examine the effect of apple and orange juices on the surface hardness of direct tooth-colored restorative materials. The materials included resin-modified glass ionomer cement (Vitremer 3M™ ESPE™ Core buildup restorative) and composite resin (Filtek™ 3M™ ESPE™ Z350). A total of 45 disks of each restorative material were prepared. The disks were divided into groups of 15, which were immersed for 7 days in deionized water (G1/G4, control group), apple juice (G2/G5), or orange juice (G3/G6). The pH of the apple juice was approximately 4.8 and the pH of the orange juice was approximately 4.9. Surface hardness tests were performed before immersion and at various times following immersion. Statistical analysis included two-way ANOVA with repeated measurement and Tukey's test. Exposure to juices significantly reduced the hardness of both materials (p material. The ionomer cement experienced a greater reduction than the composite resin (p = 0.000). There was no significant difference in the effect of apple and orange juices. Juice box-type fruit juices reduced the hardness of direct tooth-colored restorative materials. Material selection should be considered when planning restorations in patients who have experienced tooth surface loss. In terms of the materials evaluated in this study, the composite material provides greater durability under acidic conditions.

  7. Molecular Packing and Arrangement Govern the Photo-Oxidative Stability of Organic Photovoltaic Materials

    KAUST Repository

    Mateker, William R.


    For long-term performance chemically robust materials are desired for organic solar cells (OSCs). Illuminating neat films of OSC materials in air and tracking the rate of absorption loss, or photobleaching, can quickly screen a material’s photo-chemical stability. In this report, we photobleach neat films of OSC materials including polymers, solution-processed oligomers, solution-processed small molecules, and vacuum-deposited small molecules. Across the materials we test, we observe photobleaching rates that span seven orders of magnitude. Furthermore, we find that the film morphology of any particular material impacts the observed photobleaching rate, and that amorphous films photobleach faster than crystalline ones. In an extreme case, films of amorphous rubrene photobleach at a rate 2500 times faster than polycrystalline films. When we compare density to photobleaching rate, we find that stability increases with density. We also investigate the relationship between backbone planarity and chemical reactivity. The polymer PBDTTPD is more photostable than it’s more twisted and less ordered furan derivitative, PBDFTPD. Finally, we relate our work to what is known about the chemical stability of structural polymers, organic pigments, and organic light emitting diode materials. For the highest chemical stability, planar materials that form dense, crystalline film morphologies should be designed for OSCs.

  8. Modeling Temperature Development of Li-ion Battery Packs using Phase Change Materials (PCM) and Fluid Flow

    DEFF Research Database (Denmark)

    Coman, Paul Tiberiu; Veje, Christian


    This paper presents a dynamic model for simulating the heat generation and the impact of Phase Change Materials (PCMs) on the maximum temperature in LiFePO4 battery cells. The model is constructed by coupling a one-dimensional electro-chemical model with a two-dimensional thermal model and fluid...... flow model in a battery pack array. Two different physics are analysed and compared, one when the heat equation is considered for the PCM (no-flow case) and another one when fluid flow is considered. The results show that by using PCMs, the maximum temperature drops considerably for both physics....... The temperature differences between the two cases is insignificant, with the observation that by adding fluid flow, the phases mixture is more uniform. Moreover, by using fluid flow, the calculation time increases excessively due to the high non-linearity....

  9. Use of wood-based materials in beef bedded manure packs: 2. Effect on odorous volatile organic compounds, odor activity value, , and nutrient concentrations. (United States)

    Spiehs, Mindy J; Brown-Brandl, Tami M; Berry, Elaine D; Wells, James E; Parker, David B; Miller, Daniel N; Jaderborg, Jeffrey P; DiCostanzo, Alfred


    The objectives of this study were to determine the effects of three types of wood-based bedding materials (kiln-dried pine wood chips, dry cedar chips, and green cedar chips) and corn stover on the concentration of odorous volatile organic compounds (VOCs) and total in bedded pack material. Four bedded packs of each bedding material were maintained for two 42-d periods ( = 32; eight replicates/bedding material). Straight- and branched-chained fatty acids, aromatic compounds, and sulfide compounds were measured from the headspace above each bedded pack. Green cedar bedding had the highest concentration of odorous VOCs, and pine chip bedding had the lowest ( materials ( materials may be better suited for a scrape-and-haul system, where the bedded pack is removed after 1 or 2 wk. Total concentrations did not differ between any of the four bedding materials over time. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  10. Lipid for biodiesel production from attached growth Chlorella vulgaris biomass cultivating in fluidized bed bioreactor packed with polyurethane foam material. (United States)

    Mohd-Sahib, Ainur-Assyakirin; Lim, Jun-Wei; Lam, Man-Kee; Uemura, Yoshimitsu; Isa, Mohamed Hasnain; Ho, Chii-Dong; Kutty, Shamsul Rahman Mohamed; Wong, Chung-Yiin; Rosli, Siti-Suhailah


    The potential to grow attached microalgae Chlorella vulgaris in fluidized bed bioreactor was materialized in this study, targeting to ease the harvesting process prior to biodiesel production. The proposed thermodynamic mechanism and physical property assessment of various support materials verified polyurethane to be suitable material favouring the spontaneous adhesion by microalgae cells. The 1-L bioreactor packed with only 2.4% (v/v) of 1.00-mL polyurethane foam cubes could achieve the highest attached growth microalgae biomass and lipid weights of 812±122 and 376±37mg, respectively, in comparison with other cube sizes. The maturity of attached growth microalgae biomass for harvesting could also be determined from the growth trend of suspended microalgae biomass. Analysis of FAME composition revealed that the harvested microalgae biomass was dominated by C16-C18 (>60%) and mixture of saturated and mono-unsaturated fatty acids (>65%), satiating the biodiesel standard with adequate cold flow property and oxidative stability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Li-Ion Pouch Cells for Vehicle Applications — Studies of Water Transmission and Packing Materials

    Directory of Open Access Journals (Sweden)

    Göran Flodberg


    Full Text Available This study includes analysis of encapsulation materials from lithium-ion pouch cells and water vapour transmission rate (WVTR measurements. WVTR measurements are performed on both fresh and environmentally stressed lithium-ion pouch cells. Capacity measurements are performed on both the fresh and the environmentally stressed battery cells to identify possible influences on electrochemical performance. Preparation of the battery cells prior to WVTR measurements includes opening of battery cells and extraction of electrode material, followed by resealing the encapsulations and adhesively mounting of gas couplings. A model describing the water diffusion through the thermal welds of the encapsulation are set up based on material analysis of the encapsulation material. Two WVTR equipments with different type of detectors are evaluated in this study. The results from the WVTR measurements show how important it is to perform this type of studies in dry environment and apply a rigorous precondition sequence before testing. Results from modelling confirm that the WVTR method has potential to be used for measurements of water diffusion into lithium-ion pouch cells. Consequently, WVTR measurements should be possible to use as a complement or alternative method to for example Karl Fisher titration.

  12. A model for numerical simulation of devolatilization and combustion of waste material in packed beds

    Energy Technology Data Exchange (ETDEWEB)

    Peters, B. [Kernforschungszentrum Karlsruhe GmbH (Germany). Inst. fuer Angewandte Thermo- und Fluiddynamik (IATF)


    The objective of this paper is to present a numerical simulation method for the calculation of an unsteady, three-dimensional flow and combustion phenomena in a packed bed of a furnace. The entire arrangement of a furnace partly filled with solid particles is separated into a gas phase and a solid phase. The gas flow within the void space between particles is approximated by flow through porous media according to Darcy`s law. The outer flow region of the combustion chamber will be modelled as a laminar/turbulent viscous flow. Therefore a set of equations, i.e. continuity, momentum and energy equation including the homogeneous combustion between a gaseous fuel and air are applied to describe accurately the behaviour of the phenomena encountered. The motion of the solid phase, as a flow of one particle past another, is accounted for by particle-to-particle friction. As heating up and combustion of particles significantly changes their size, temeprature and composition this behaviour is treated by a special particle modelling step. It takes into account a size reduction due to heterogeneous combustion, non-uniform temperature distribution due to internal heat generation and both convective and radiative heat transfer within the gas phase and the solid phase, and a varying composition due to pyrolysation and gasification. Similar to the gas phase, a set of conservation equations applied to particles yields the solution for the relevant variables. The sets of equations for both the solid and the gas phases will be solved by a time-marching finite volume approach on an unstructured computational mesh with arbitrarily shaped cells. This novelty enhances body fitted meshing and resolution of high gradient domains. An efficient non-iterative solution algorithm is employed, which allows the size of the computational time step to be controlled solely by accuracy considerations, rather than numerical stability, in the interest of economy. [Deutsch] Innerhalb des vorliegenden

  13. Low water permeability through hydrophobicity : COIN Project P1 advanced cementing materials : SP 1.5 F Low porosity / permeability


    Justnes, Harald


    The durability and aesthetic appearance of concrete may be improved by the addition of hydrophobizing agents as a consequence of reduced water permeability. Hydrophobizing agents lead to less water absorption at the same time as they let water vapour out. This may lead to a dryer interior over time and thereby reduced rate of detrimental reactions needing liquid water as reaction medium. The ingress of water born aggressives like chlorides will be reduced (in particular in marine splash zones...

  14. Low water permeability through hydrophobicity : COIN Project P1 advanced cementing materials : SP 1.5 F Low porosity / permeability


    Justnes, Harald


    - The durability and aesthetic appearance of concrete may be improved by the addition of hydrophobizing agents as a consequence of reduced water permeability. Hydrophobizing agents lead to less water absorption at the same time as they let water vapour out. This may lead to a dryer interior over time and thereby reduced rate of detrimental reactions needing liquid water as reaction medium. The ingress of water born aggressives like chlorides will be reduced (in particular in marine splash ...

  15. Mesophilic hydrogen production in acidogenic packed-bed reactors (APBR) using raw sugarcane vinasse as substrate: Influence of support materials. (United States)

    Nunes Ferraz Júnior, Antônio Djalma; Etchebehere, Claudia; Zaiat, Marcelo


    Bio-hydrogen production from sugarcane vinasse in anaerobic up-flow packed-bed reactors (APBR) was evaluated. Four types of support materials, expanded clay (EC), charcoal (Ch), porous ceramic (PC), and low-density polyethylene (LDP) were tested as support for biomass attachment. APBR (working volume - 2.3 L) were operated in parallel at a hydraulic retention time of 24 h, an organic loading rate of 36.2 kg-COD m(-3) d(-1), at 25 °C. Maximum volumetric hydrogen production values of 509.5, 404, 81.4 and 10.3 mL-H2 d(-1) L(-1)reactor and maximum yields of 3.2, 2.6, 0.4 and 0.05 mol-H2 mol(-1) carbohydrates total, were observed during the monitoring of the reactors filled with LDP, EC, Ch and PC, respectively. Thus, indicating the strong influence of the support material on H2 production. LDP was the most appropriate material for hydrogen production among the materials evaluated. 16S rRNA gene by Terminal Restriction Fragment Length Polymorphism (T-RFLP) analysis and scanning electron microscopy confirmed the selection of different microbial populations. 454-pyrosequencing performed on samples from APBR filled with LDP revealed the presence of hydrogen-producing organisms (Clostridium and Pectinatus), lactic acid bacteria and non-fermentative organisms. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Nutritive value of palm oil sludge fermented with Aspergillus niger after stored in different packing materials

    Directory of Open Access Journals (Sweden)

    T Pasaribu


    Full Text Available An experiment has been conducted to determine the effect of type of packaging and time of storage on fermented palm oil sludge. The palm oil sludge was fermented with Aspergillus niger, dried, kept in differentpackaging materials (plastic bags, feed bag, and paper bag and stored under room temperatures for 12 weeks. The experiment was assigned in a split plot design (3x7. The parameters measured were water content, crude protein, soluble nitrogen, true protein, in vitro dry matter (IVDMD and true protein digestibilities (IVTPD, total in vitro digestible protein, and the activities of mannanase and cellulase. Results showed that fermented palm oil sludge stored for 12 weeks increased the water content, decreased the true protein and fiber contents, and also reduced the activity of mannanase and cellulase and in vitro dry matter digestibility but no changes on the crude protein content, protein digestibility, and total digestible protein. It was concluded that fermented palm oil sludge should be kept in feed bag under room temperature if to be stored for 12 weeks.

  17. High-Throughput Image Analysis of Fibrillar Materials: A Case Study on Polymer Nanofiber Packing, Alignment, and Defects in Organic Field Effect Transistors. (United States)

    Persson, Nils E; Rafshoon, Joshua; Naghshpour, Kaylie; Fast, Tony; Chu, Ping-Hsun; McBride, Michael; Risteen, Bailey; Grover, Martha; Reichmanis, Elsa


    High-throughput discovery of process-structure-property relationships in materials through an informatics-enabled empirical approach is an increasingly utilized technique in materials research due to the rapidly expanding availability of data. Here, process-structure-property relationships are extracted for the nucleation, growth, and deposition of semiconducting poly(3-hexylthiophene) (P3HT) nanofibers used in organic field effect transistors, via high-throughput image analysis. This study is performed using an automated image analysis pipeline combining existing open-source software and new algorithms, enabling the rapid evaluation of structural metrics for images of fibrillar materials, including local orientational order, fiber length density, and fiber length distributions. We observe that microfluidic processing leads to fibers that pack with unusually high density, while sonication yields fibers that pack sparsely with low alignment. This is attributed to differences in their crystallization mechanisms. P3HT nanofiber packing during thin film deposition exhibits behavior suggesting that fibers are confined to packing in two-dimensional layers. We find that fiber alignment, a feature correlated with charge carrier mobility, is driven by increasing fiber length, and that shorter fibers tend to segregate to the buried dielectric interface during deposition, creating potentially performance-limiting defects in alignment. Another barrier to perfect alignment is the curvature of P3HT fibers; we propose a mechanistic simulation of fiber growth that reconciles both this curvature and the log-normal distribution of fiber lengths inherent to the fiber populations under consideration.

  18. Influence of batch-to-batch reproducibility of Luna C-18(2) packing material, nature of column wall material, and column diameter on the liquid chromatographic analysis of basic analytes

    NARCIS (Netherlands)

    Vervoort, RJM; Ruyter, E; Debets, AJJ; Claessens, HA; Cramers, CA; de Jong, GJ

    This paper discusses aspects arising on transferring liquid chromatography (LC) methods developed on conventional size columns to micro LC, i.e. the influence of batch-to-batch reproducibility of packing material, the nature of the column wall material, and the column inner diameter. it was shown

  19. Optimized packings with applications

    CERN Document Server

    Pintér, János


    This volume presents a selection of case studies that address a substantial range of optimized object packings (OOP) and their applications. The contributing authors are well-recognized researchers and practitioners. The mathematical modelling and numerical solution aspects of each application case study are presented in sufficient detail. A broad range of OOP problems are discussed: these include various specific and non-standard container loading and object packing problems, as well as the stowing of hazardous and other materials on container ships, data centre resource management, automotive engineering design, space station logistic support, cutting and packing problems with placement constraints, the optimal design of LED street lighting, robust sensor deployment strategies, spatial scheduling problems, and graph coloring models and metaheuristics for packing applications. Novel points of view related to model development and to computational nonlinear, global, mixed integer optimization and heuristic st...

  20. Hydrophobic surface modification of TiO2 nanoparticles for production of acrylonitrile-styrene-acrylate terpolymer/TiO2 composited cool materials (United States)

    Qi, Yanli; Xiang, Bo; Tan, Wubin; Zhang, Jun


    Hydrophobic surface modification of TiO2 was conducted for production of acrylonitrile-styrene-acrylate (ASA) terpolymer/titanium dioxide (TiO2) composited cool materials. Different amount of 3-methacryloxypropyl-trimethoxysilane (MPS) was employed to change hydrophilic surface of TiO2 into hydrophobic surface. The hydrophobic organosilane chains were successfully grafted onto TiO2 through Sisbnd Osbnd Ti bonds, which were verified by Fourier transformed infrared spectra and X-ray photoelectron spectroscopy. The water contact angle of the sample added with TiO2 modified by 5 wt% MPS increased from 86° to 113°. Besides, all the ASA/TiO2 composites showed significant improvement in both solar reflectance and cooling property. The reflectance of the composites throughout the near infrared (NIR) region and the whole solar wavelength is increased by 113.92% and 43.35% compared with pristine ASA resin. Simultaneously, significant drop in temperature demonstrates excellent cooling property. A maximum decrease approach to 27 °C was observed in indoor temperature test, while a decrease around 9 °C tested outdoors is achieved.

  1. Packing Smart

    Centers for Disease Control (CDC) Podcasts


    In this podcast for kids, the Kidtastics talk about packing a lunch that's not boring and is full of the power and energy kids need to make it through the day.  Created: 8/22/2011 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 8/22/2011.

  2. Power Packing

    Centers for Disease Control (CDC) Podcasts


    In this podcast for kids, the Kidtastics talk about how to pack a lunch safely, to help keep you from getting sick.  Created: 8/16/2011 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 8/16/2011.

  3. The Role of Charge Density and Hydrophobicity on the Biocidal Properties of Self-Protonable Polymeric Materials. (United States)

    Matrella, Simona; Vitiello, Carmela; Mella, Massimo; Vigliotta, Giovanni; Izzo, Lorella


    Intrinsic antimicrobial thermoplastic A(BC)n copolymers (n = 1, 2, 4), where A was poly(ethylene glycol) (PEG), BC was a random chain of methylmethacrylate (MMA), and alkyl-aminoethyl methacrylate (AAEMA), were synthesized and the antimicrobial activity and hemolyticity were evaluated on plaques obtained by casting as a function of the architecture, the N-substituent groups of the AAEMAs (methyl, ethyl, isopropyl, and tert-butyl groups) and the hydrophobic/charge density balance. Antimicrobial effectiveness and efficiency is controlled by the surface charge density and by the influence of N-alkyl groups on the surface morphology. Also interestingly, it is the absence of hemolitytic activity in all copolymers. In presence of Escherichia coli, the A(BC)2 copolymer with 40% of N-methyl groups is the most efficient, killing 91% of the bacteria already after 1.5 h. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. [Glass fibre HEPA filters. II. Communication: Microbiological and physico-chemical researchs on used and unusued, hydrophilic and hydrophobic filter materials in an air conditioning plant (author's transl)]. (United States)

    Rüden, H; Mihm, U; Schoemann, D; Botzenhart, K; Thofern, E


    Hydrophobic and hydrophilic, used and unused HEPA filters from various manufacturers, inoculated with vegetative bacteria, bacterial and fungal spores, were exposed to clean outside air for up to 17 weeks in an air conditioning plant. With relative humidities up to 60%, an increase in germ count could not be found. The rate of killing the micro-organisms inoculated were different and were generally higher on used filters. The low water content of the filter material was apparently not sufficient for microbial growth. In addition, the increase in electric conductivity and reduction of pH value resulting from deposition of substances from the outside air with an acid reaction ascertained in the aqueous filter extracts had a negative effect on the living conditions of the microorganisms.

  5. Relationship between Surface Properties and In Vitro Drug Release from Compressed Matrix Containing Polymeric Materials with Different Hydrophobicity Degrees


    Yarce, Cristhian J.; Echeverri, Juan D.; Palacio, Mario A.; Rivera, Carlos A.; Salamanca, Constain H.


    This work is the continuation of a study focused on establishing relations between surface thermodynamic properties and in vitro release mechanisms using a model drug (ampicillin trihydrate), besides analyzing the granulometric properties of new polymeric materials and thus establishing the potential to be used in the pharmaceutical field as modified delivery excipients. To do this, we used copolymeric materials derived from maleic anhydride with decreasing polarity corresponding to poly(isob...

  6. Study and selection of structured packing material: metallic, polymeric or ceramic to operate a column of absorption polluting gases coming from brick kilns efficiently; Estudio y seleccion de material empaque estructurado: metalico, polimerico o ceramico, para operar eficientemente una columna de absorcion de gases contaminantes provenientes de hornos tabiqueros

    Energy Technology Data Exchange (ETDEWEB)

    Salazar P, A.


    In this research three structured packing materials were characterized: a metallic, polymeric and ceramic. The study of the physical properties of structured packing materials, and their behavior within the absorption column allowed to suggest a gas-liquid contactor material with higher mechanical and chemical resistance, which is more efficient for the treatment of sour gases from brick kilns. To study the mechanical properties (hardness, tension and elastic modulus) were used procedures of the American Society for Testing Materials, as well as resistance to corrosion. The geometric characteristics, the density, the melting temperature and the weight were tested with procedures of the measuring equipment. The structure was evaluated by X-ray diffraction, morphology was observed by scanning electron microscopy coupled to a sound of dispersive energy of X-ray, to quantify elemental chemical composition. The interaction of gas-liquid contactors materials in presence of CO{sub 2}, was evaluated in three absorption columns built of Pyrex glass, with a diameter of 0.1016 m, of 1.5 m in height, 0.0081m{sup 2} cross-sectional area, packed with every kind of material: metallic, polymeric and ceramic, processing a gas flow of 20m{sup 3} / h at 9% CO{sub 2}, in air and a liquid flow to 30% of Mea 5 L/min. The results of the properties studied were by the metallic material: more density, higher roughness, the greater tensile strength, greater resistance to corrosion in the presence of an aqueous solution of monoethanolamine (Mea) to 30% by weight, improvement more efficient absorption of CO{sub 2}, and higher modulus of elasticity. The polymeric material was characterized to have lower hardness, lower roughness, lower density, lower melting temperature, greater resistance to corrosion in the presence of 1 N H{sub 2}SO{sub 4} aqueous solution, and allowed an absorption efficiency of CO{sub 2}, 2% lower than that presented by the material metallic. The ceramic material found to

  7. Random packing of colloids and granular matter

    NARCIS (Netherlands)

    Wouterse, A.


    This thesis deals with the random packing of colloids and granular matter. A random packing is a stable disordered collection of touching particles, without long-range positional and orientational order. Experimental random packings of particles with the same shape but made of different materials

  8. Significance and technology of coal mine packing (United States)

    Wang, Yunliang


    Packing is a kind of mining method which is used to fill the goaf with filling material to control the movement of overlying strata and reduce the deformation of the surface. This paper mainly discusses the significance of coal mine packing, and introduces the current method of filling and mining. Finally, the future of coal mine packing is forecasted.

  9. A Super Cooled, Non-toxic, Non-flammable Phase Change Material Thermal Pack for Portable Life Support Systems Project (United States)

    National Aeronautics and Space Administration — The concept development and test of a water-based, advanced Phase Change Material (PCM) heat sink is proposed. Utilizing a novel material choice for both an...

  10. A Super Cooled, Non-toxic, Non-flammable Phase Change Material Thermal Pack for Portable Life Support Systems Project (United States)

    National Aeronautics and Space Administration — The continuation of concept development and test of a water-based, advanced Phase Change Material (PCM) heat sink is proposed. Utilizing a novel material choice for...

  11. Aeration effect on the efficiency of swine manure treatment in a trickling filter packed with organic materials. (United States)

    Garzón-Zúñiga, M A; Lessard, P; Aubry, G; Buelna, G


    Effect of aeration rate on the removal of organic matter and nitrogen and on the formation of NH3, N2O and N2 was studied for an extensive biofiltration system packed with an organic media, which was used to treat pig manure. The results show high removal of BOD5 and TSS (99 and > or = 98%), independently of the four aeration rate tested (3.4-34 m3/m2 x h). Aeration rate > or = 4.4 m/h resulted in high ammonia stripping during start-up (> or = 1.0 kg NH3-N/m3 of swine manure treated), while using 3.4 m/h only 0.3 kg NH3-N/m3 were stripped. Complete nitrification was achieved after day 100 of operation, except in the biofilter with the lowest aeration rate. Simultaneous denitrification established in all the biofilters. Applying an aeration rate of 9.4 m/h up to 1.2 kg nitrogen was removed in the form of N2 for each m3 of swine manure treated. Contrary to the expectations, N2 formation and release increased with the aeration rate. This particular behaviour seems to be related to the punctual accumulation of water layers inside the biofilters, caused by the air force flowing in the opposite direction to the water flux. N2O production was quite similar in all biofilters (between 0.25-0.36 kg N2O-N/m3 of swine manure treated).

  12. Preparation and performance of Pt/PTFE/Foam SiC as a hydrophobic catalyst for LPCE

    Energy Technology Data Exchange (ETDEWEB)

    He, Jianchao; Wang, Heyi, E-mail:; Xiao, Chengjian; Li, Jiamao; Chen, Ping; Hou, Jingwei


    Highlights: • A new type of foam material, Foam SiC with three-dimensional network structure, was chosen as the carrier of catalyst. • Foam SiC was hydrophobic treated by PTFE, and achieved a good hydrophobic property. • Pt/PTFE/Foam SiC was prepared by impregnation method with Pt-organic solution and gaseous phase reduction method. • The hydrophobic catalysts were packed with Dixon phosphor bronze gauze rings (about 3 mm × 3 mm) in LPCE system to test the catalytic performance. • The effect of different size of the catalyst on LPCE was been tested. - Abstract: Platinum catalysts supported on a composite of polytetrafluoroethylene (PTFE) and Foam SiC (Pt/PTFE/Foam SiC) have been proposed and prepared by an impregnation method. The as-prepared Pt/PTFE/Foam SiC was characterized by compression load testing, dynamic contact angle measurement, SEM, XRD, and TEM. The results show that the catalyst prepared by triple hydrophobic treatment had an initial contact angle of 134.2°, a good compression performance of 3.2 MPa, and platinum nanoparticles of 12.1 nm (average size). The catalytic activity of the catalyst was tested with different packing methods, reaction temperatures, and gas-liquid ratios. An excellent hydrogen isotope exchange performance was observed using a hydrophilic packing material-to-catalyst ratio of 25% and reaction temperature of 80 °C. Pt/PTFE/Foam SiC may be used as a hydrophobic catalyst for a water detritiation system (WDS) via a liquid-phase catalytic exchange process (LPCE).

  13. Preliminary Evaluation of Commercial Off the Shelf (COTS) Packing Materials for Flight Medication Dispenser (FMD) Technology Development (United States)

    Du, B.; Daniels, V.; Crady, C.; Putcha, L.


    This slide presentation reviews preliminary results of the program to evaluate Commercial Off the Shelf (COTS) packaging materials for pharmaceutical stability. The need for improved packaging is due to possible changes in chemical and/or physical properties of the drugs, which cause reported reduced potency and/or altered bioavailability and decreased efficacy.

  14. Improvement of airtight property and workability of joint packing material; Teikeimejizai no shirusei oyobi sagyosei no kaizen

    Energy Technology Data Exchange (ETDEWEB)

    Ouchi, Tatsuya.; Harada, Tsutomu.; Ando, Hideyuki.; Yamato, Tsugio. [Kurosaki Corp., Fukuoka (Japan). Technical Research Center


    It is connected, and many refractories s are being used with continuous cast law. An including air volume from these union parts causes the quality decline of the steel and the problem of unusual loss around the union part of the refractories. Therefore, there is a big thing in the part, which the eye area material used for the union part of the refractories for the continuous cast plays. This time, the fixed form area material of the hard type which has a sticker and work between the excellent heat could get it in comparison with the usual fixed form area material for the purpose of the improvement in the sticker of the eye area material and the work (acceptable convenience time in the normal temperature form, the space of the heat) as a result of examining the application of the Al metal which doesn`t react easily with the new binder and the water. As for the utility test as well, it is reported because it was used without problem and that validity could be confirmed. (NEDO)

  15. Packing element of a packer

    Energy Technology Data Exchange (ETDEWEB)

    Safin, V.A.


    The packing element of a packer is proposed which consists of an elastic core and outer layer made of plastic sealing material. It is distinguished by the fact that in order to facilitate removal of the packing element from the site of installation, the outer layer has a sublayer made of polymer material which is chemically inactive in relationship to the material of the core, for example polytetrafluoroethylene. The element is also distinguished by the fact that the outer layer together with the sublayer is attached to the core through a nonhardening and nondrying glue composition, for example, based on rubber, rosin, lanolin, vaseline oil and zinc oxide.

  16. 48 CFR 452.247-72 - Packing for Domestic Shipment. (United States)


    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Packing for Domestic... Packing for Domestic Shipment. As prescribed in 447.305-10(b), insert the following clause: Packing for Domestic Shipment (FEB 1988) Material shall be packed for shipment in such a manner that will insure...

  17. Structure-Packing-Property Correlation of Self-Sorted vs. Interdigitated Assembly in TTF.TCNQ Based Charge-Transport Materials. (United States)

    Niyas, M A; Ramakrishnan, Remya; Vijay, Vishnu; Hariharan, Mahesh


    Among the various donor-acceptor (D-A) charge transfer cocrystals investigated in the past few decades, tetrathiafulvalene-tetracyanoquinodimethane (F.Q, popularly known as TTF.TCNQ) based cocrystals have fascinated materials chemists owing to its packing and exceptional properties. Here, crystallographic information files of eighteen F.Q based cocrystals were extracted from Cambridge Structural Database and classified into Class 1 (D on D and A on A segregated stacks; F.Q, F1.Q - F6.Q and F.Q1), Class 2 (-A-D-A-D-A-D- mixed stacks; F6a.Q - F11.Q and F.Q2) and Class 3 (-A-D-A-A-D-A-; Class 3a (F12.Q and F13.Q) and -D-D-A-A-D-D-; Class 3b (F14.Q)) systems based on their packing modes. PIXEL calculations revealed that the Q on Q dimer is the energetically most favored dimer in F.Q, the substituents on F capable of forming hydrogen bonding, C...S and other weak intermolecular interactions resulted in the greater stability of F on F dimer for F1.Q - F6.Q (except F2.Q). Band structure of F.Q and F6.Q with high interaction of electronic orbitals between D on D and A on A in segregated stacks were found to be metal-like (band gap, Eg = 0.003 eV) and metallic (overlapping bands in the Fermi level) respectively while the polymorph of F6.Q belonging to Class 2 (F6a.Q) displayed a semiconductor-type band structure (Eg = 0.053 eV). F12.Q of Class 3a exhibited a metal-like band structure (Eg = 0.001 eV). © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Modelling Assisted Design and Synthesis of Highly Porous Materials for Chemical Adsorbents (United States)


    and the organic groups protrude to define a hydrophobic region. Typically, these organic groups pack efficiently and any sorption phenomena arise due...une région hydrophobe . Généralement, ces groupes organiques s’empilent de manière efficace et les phénomènes de sorption prennent naissance en...smaller pore zeolitic materials and importantly, confirm that there are accessible micropores in 1. The desorption cycle showed evidence of

  19. Interfacial Engineering of Perovskite Solar Cells by Employing a Hydrophobic Copper Phthalocyanine Derivative as Hole-Transporting Material with Improved Performance and Stability. (United States)

    Jiang, Xiaoqing; Yu, Ze; Lai, Jianbo; Zhang, Yuchen; Hu, Maowei; Lei, Ning; Wang, Dongping; Yang, Xichuan; Sun, Licheng


    In high-performance perovskite solar cells (PSCs), hole-transporting materials (HTMs) play an important role in extracting and transporting the photo-generated holes from the perovskite absorber to the cathode, thus reducing unwanted recombination losses and enhancing the photovoltaic performance. Herein, solution-processable tetra-4-(bis(4-tert-butylphenyl)amino)phenoxy-substituted copper phthalocyanine (CuPc-OTPAtBu) was synthesized and explored as a HTM in PSCs. The optical, electrochemical, and thermal properties were fully characterized for this organic metal complex. The photovoltaic performance of PSCs employing this CuPc derivative as a HTM was further investigated, in combination with a mixed-ion perovskite as a light absorber and a low-cost vacuum-free carbon as cathode. The optimized devices [doped with 6 % (w/w) tetrafluoro-tetracyano-quinodimethane (F4TCNQ)] showed a decent power conversion efficiency of 15.0 %, with an open-circuit voltage of 1.01 V, a short-circuit current density of 21.9 mA cm-2 , and a fill factor of 0.68. Notably, the PSC devices studied also exhibited excellent long-term durability under ambient condition for 720 h, mainly owing to the introduction of the hydrophobic HTM interlayer, which prevents moisture penetration into the perovskite film. The present work emphasizes that solution-processable CuPc holds a great promise as a class of alternative HTMs that can be further explored for efficient and stable PSCs in the future. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Effect of TiO2 Powder on the Surface Morphology of Micro/Nanoporous Structured Hydrophobic Fluoropolymer Based Composite Material

    Directory of Open Access Journals (Sweden)

    Bichitra Nanda Sahoo


    Full Text Available The present work reports a simple and effective way to produce hydrophobic foams with polyvinylidene fluoride (PVDF and TiO2 by using a phase separation technique. This method involved the phase separation during the deposition of PVDF from its DMF solution with nonsolvent water in the presence of TiO2. The surface morphology of hydrophobic surfaces was characterized by Field Emission Scanning Electron Microscope (FESEM. The maximum water contact angle of 129° was observed. The results confirm that the surface texture of polymer composite exhibits mixture of microporous and nanoporous structure. The impact of TiO2 on the wettability property of polymer composite has been studied. The proposed methodology might find applications in the preparation of hydrophobic surfaces for industrial applications.

  1. Experiment and simulation of a LiFePO4 battery pack with a passive thermal management system using composite phase change material and graphite sheets (United States)

    Lin, Chunjing; Xu, Sichuan; Chang, Guofeng; Liu, Jinling


    A passive thermal management system (TMS) for LiFePO4 battery modules using phase change material (PCM) as the heat dissipation source to control battery temperature rise is developed. Expanded graphite matrix and graphite sheets are applied to compensate low thermal conductivity of PCM and improve temperature uniformity of the batteries. Constant current discharge and mixed charge-discharge duties were applied on battery modules with and without PCM on a battery thermal characteristics test platform. Experimental results show that PCM cooling significantly reduces the battery temperature rise during short-time intense use. It is also found that temperature uniformity across the module deteriorates with the increasing of both discharge time and current rates. The maximum temperature differences at the end of 1C and 2C-rate discharges are both less than 5 °C, indicating a good performance in battery thermal uniformity of the passive TMS. Experiments on warm-keeping performance show that the passive TMS can effectively keep the battery within its optimum operating temperature for a long time during cold weather uses. A three dimensional numerical model of the battery pack with the passive TMS was conducted using ANSYS Fluent. Temperature profiles with respect to discharging time reveal that simulation shows good agreement with experiment at 1C-discharge rate.

  2. Hydrophobicity and its applications (United States)

    Rios, Fabian

    Two different types of smart surfaces that are able to change their hydrophobicity by different stimuli are presented. In both types, the self assembled mono-layers have mixtures of hydrophobic moieties with active ligands. In the first, with biotin being the ligand, wetting changes induced by streptavidin binding onto the biotin were demonstrated and evaluated for different biotin concentrations on the surface and streptavidin concentrations in solution. In the second, aminated silanes allow wetting to be sensitive to pH changes and, by choosing their appropriate proportion of amines on the surface, can be made to switch hydrophobicity at a desired pH. Wetting of hydrophobic porous substrates induced by pressure, surfactants and pH was also studied for the pore diameters in the range 20-200 nm. Different mechanisms of wetting by amphiphiles were identified for high cmc and low cmc cases. In the latter, represented by phospholipids of the cell membrane, wetting occurs only in contact between the hydrophobic pores and the membrane, as was experimentally illustrated. It led to formulation of a new concept of drug delivery using hydrophobicity switching by membrane amphiphiles. Hydrophobic nanocontainers with dual release mechanism combining hydrophobicity switching by amphiphiles and by pH were explored as a potential new drug delivery system.

  3. Super-hydrophobic fluorine containing aerogels (United States)

    Coronado, Paul R [Livermore, CA; Poco, John F [Livermore, CA; Hrubesh, Lawrence W [Pleasanton, CA


    An aerogel material with surfaces containing fluorine atoms which exhibits exceptional hydrophobicity, or the ability to repel liquid water. Hydrophobic aerogels are efficient absorbers of solvents from water. Solvents miscible with water are separated from it because the solvents are more volatile than water and they enter the porous aerogel as a vapor across the liquid water/solid interface. Solvents that are immisicble with water are separated from it by selectively wetting the aerogel. The hydrophobic property is achieved by formulating the aerogel using fluorine containing molecules either directly by addition in the sol-gel process, or by treating a standard dried aerogel using the vapor of fluorine containing molecules.

  4. Electrohydrodynamics near hydrophobic surfaces. (United States)

    Maduar, S R; Belyaev, A V; Lobaskin, V; Vinogradova, O I


    We show that an electro-osmotic flow near the slippery hydrophobic surface depends strongly on the mobility of surface charges, which are balanced by counterions of the electrostatic diffuse layer. For a hydrophobic surface with immobile charges, the fluid transport is considerably amplified by the existence of a hydrodynamic slippage. In contrast, near the hydrophobic surface with mobile adsorbed charges, it is also controlled by an additional electric force, which increases the shear stress at the slipping interface. To account for this, we formulate electrohydrodynamic boundary conditions at the slipping interface, which should be applied to quantify electro-osmotic flows instead of hydrodynamic boundary conditions. Our theoretical predictions are fully supported by dissipative particle dynamics simulations with explicit charges. These results lead to a new interpretation of zeta potential of hydrophobic surfaces.


    Directory of Open Access Journals (Sweden)

    Valderi D. Leite


    Full Text Available About 245 thousand tones of municipal solid w aste are collected daily in Brazil. Nearly 32 thousand tones of the collected amount are treated in sanitary landfill, which generates biogas and leachate as byproduct. The leachate resulting from sanitary landfill contains high concentration of carbonaceous and nitrogenized material. The crucial question is that the biodegradation of the carbonaceous material is difficult as long as the nitrogenized material is presen t in the form of ammoniacal nitrogen (NH 4 + , which compromises performance of biological tr eatment process. Therefore, a physical and chemical treatment of the leachate should be done before its biological treatment, especially for reduction of ammoniacal nitr ogen concentration and for propitiating the realization of application of biological treatment. The treatment of leachate requires specific consideration, which is not needed fo r other types of waste. In the specific case in this study, where ammoniacal nitrogen concentration was about 2,200 mgN L -1 and the BOD 5 /COD ratio was 0.3, the study of ammonia stripping process was performed. Ammonia stripping process was studied in pack ed towers of 35 L capacity each and the parameters investigated were pH, ratio of contact area/leach volume and the aeration time. One of the parameters that influenced most in efficiency of ammonia stripping process was pH of the leachate since it contributes in conversion of ammoniacal nitrogen from NH 4 + to NH 3 .

  6. Hydrophobicity measurements of microfiltration and ultrafiltration membranes.

    NARCIS (Netherlands)

    Keurentjes, J.T.F.; Harbrecht, J.G.; Brinkman, D.; Hanemaaijer, J.H.; Cohen Stuart, M.A.; Riet, van 't K.


    A method for the determination of the hydrophobicity of membrane materials is developed. The advantage of this method over existing methods is that it is not influenced by the presence of the pores. A piece of the membrane material is submerged horizontally in a liquid with surface tension L.

  7. Reduction of microbial biofilm formation using hydrophobic nano ...

    African Journals Online (AJOL)

    hydrophobic coating on cooling tower fill materials – polypropylene cooling tower fill material was coated with nano-silica. The effectiveness of the hydrophobic coating was investigated for a 6-month test period in a model cooling tower system, ...

  8. Development of an effective valve packing program

    Energy Technology Data Exchange (ETDEWEB)

    Hart, K.A.


    Current data now shows that graphite valve packing installed within the guidance of a controlled program produces not only reliable stem sealing but predictable running loads. By utilizing recent technological developments in valve performance monitoring for both MOV`s and AOV`s, valve packing performance can be enhanced while reducing maintenance costs. Once known, values are established for acceptable valve packing loads, the measurement of actual valve running loads via the current MOV/AOV diagnostic techniques can provide indication of future valve stem sealing problems, improper valve packing installation or identify the opportunity for valve packing program improvements. At times the full benefit of these advances in material and predictive technology remain under utilized due to simple past misconceptions associated with valve packing. This paper will explore the basis for these misconceptions, provide general insight into the current understanding of valve packing and demonstrate how with this new understanding and current valve diagnostic equipment the key aspects required to develop an effective, quality valve packing program fit together. The cost and operational benefits provided by this approach can be significant impact by the: elimination of periodic valve repacking, reduction of maintenance costs, benefits of leak-free valve operation, justification for reduced Post Maintenance Test Requirements, reduced radiation exposure, improved plant appearance.

  9. Packing properties 1-alkanols and alkanes in a phospholipid membrane

    DEFF Research Database (Denmark)

    Westh, Peter


    and long chain alcohols. On the basis of these observations, previously published information on the structure of the membrane-solute complexes and the free volume properties of (pure) phospholipid membranes, we suggest that two effects dominate the packing properties of hydrophobic solutes in DMPC. First......, perturbation of the tightly packed interfacial zone around the ester bonds and first few methylene groups of DMPC brings about a positive contribution to Vm(puremem). This effect dominates the volume behavior for alcohols like 1-butanol, 1-pentanol and 1-hexanol. More hydrophobic solutes penetrate......We have used vibrating tube densitometry to investigate the packing properties of four alkanes and a homologous series of ten alcohols in fluid-phase membranes of dimyristoyl phosphatidylcholine (DMPC). It was found that the volume change of transferring these compounds from their pure states...

  10. TLC Pack Unpacked (United States)

    Oberhofer, Margret; Colpaert, Jozef


    TLC Pack stands for Teaching Languages to Caregivers and is a course designed to support migrants working or hoping to work in the caregiving sector. The TLC Pack resources range from A2 to B2 level of the Common European Framework of Reference for Languages (CEFR), and will be made available online in the six project languages: Dutch, English,…

  11. Packing degenerate graphs greedily

    Czech Academy of Sciences Publication Activity Database

    Allen, P.; Böttcher, J.; Hladký, J.; Piguet, Diana


    Roč. 61, August (2017), s. 45-51 ISSN 1571-0653 R&D Projects: GA ČR GJ16-07822Y Institutional support: RVO:67985807 Keywords : tree packing conjecture * graph packing * graph processes Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics

  12. Packing Structures of Soft Particles by Compression (United States)

    Lee, Sangwoo; Chen, Liwen

    Recent discovery of Frank-Kasper phases in self-assembling materials stimulates exploration of new crystal structure to understand the origin of the complex packing structures nature selects. We investigated packing structures by block copolymer micelles in an aqueous/organic solvent mixture. The micellar solution showed two phase states of globular polymer phase and liquid phase containing homogeneously dispersed polymeric micelles. The micelles developed a close-packed order which transforms into a Frank-Kasper C14 phase as the concentration of block copolymer surfactant increases. This transition aligns with the sphericity criteria.

  13. Hydrophobic interactions and chemical reactivity

    NARCIS (Netherlands)

    Otto, Sijbren; Engberts, Jan B.F.N.


    This perspective describes how kinetic studies of organic reactions can be used to increase our understanding of hydrophobic interactions. In turn, our understanding of hydrophobic interactions can be used as a tool to influence chemical reactions.

  14. Layered circle packings

    Directory of Open Access Journals (Sweden)

    David Dennis


    Full Text Available Given a bounded sequence of integers {d0,d1,d2,…}, 6≤dn≤M, there is an associated abstract triangulation created by building up layers of vertices so that vertices on the nth layer have degree dn. This triangulation can be realized via a circle packing which fills either the Euclidean or the hyperbolic plane. We give necessary and sufficient conditions to determine the type of the packing given the defining sequence {dn}.

  15. Influence of hydrophobic characteristic of organo-modified precursor ...

    Indian Academy of Sciences (India)

    The objective of this study is to design new hybrid silica materials as templates with hydrophobic properties, prepared at room temperature by a base catalyzed sol–gel process. As silica sources, organoalkoxysilanes functionalized with short hydrophobic chains were used: tetraethylorthosilicate (TEOS), ...

  16. Incorporation of Certain Hydrophobic Excipients in the Core of Melt ...

    African Journals Online (AJOL)

    Patrick Erah

    been used to modify the dissolution rates of drug particles. The present study investigated how the incorporation of hydrophobic materials (talc or magnesium stearate) in the core of such granules may further retard drug release. Method - The hydrophobic powder was mixed with the drug (paracetamol) powder prior to melt.

  17. [Glass fibre HEPA filters. I. Communication: Microbiological and physico-chemical researchs on used and unused, hydrophobic and hydrophilic filter materials at relative humidities up to 98% in the climatic test chamber (author's transl)]. (United States)

    Rüden, H; Botzenhart, K; Mihm, U; Tenge, H; Thofern, E


    1. At high humidities up to 98%, an increase in bacteria cannot be detected. This applies to all HEPA filters investigated from the various manufacturers, independent of whether they are hydrophilic or hydrophobic, used or unused. 2. Fungal growth can only be obtained when large amounts of nutrient material (e.g. bacterial cultures) are present. In these cases a streaky growth appears . Under normal conditions of use, however, such intense contamination is not to be expected because of the prefiltration. Penetration only occurs with fungi. 3. Limitation of supply air humidity to 90% or less seems therefore to be unjustified on the basis of these investigations, if prefiltration and a satisfactory intermixing section can be guaranteed technically, and condensation is avoided. 4. HEPA filters of Grade S from various manufacturers and with different behaviour with respect to water do not allow bacterial growth even in the presence of nutrients. Additional measures for the killing of bacteria are therefore not considered necessary.

  18. Evaluation of the shelf life of sterile instrument packs. (United States)

    Butt, W E; Bradley, D V; Mayhew, R B; Schwartz, R S


    No published studies have specifically addressed the shelf life of sterile packaging materials commonly used in dentistry. This study examined the effect of time on the sterile integrity: paper envelopes, peel pouches, and nylon sleeves. Seven thousand two hundred sample packs, each containing three glass rods, were prepared and steam sterilized. After sterilization, half the packs (control packs) were immediately opened and the contents were analyzed for bacterial contamination. The other half (test packs) were randomly sorted and stored in dental treatment operatories. At monthly intervals for 12 months, 100 packs of each type were similarly opened and analyzed. The contamination rates between the control packs were not significantly different from one another. Differences in contamination rates between control packs and test packs for both the paper envelopes (0.4% and 0.7%) and the peel pouches (0.2% and 0.2%) were also insignificant. However, a significant difference (p less than 0.01) between control and test packs (0.3% and 1.5%) was found for the nylon sleeves. This increase was not time related and was attributed to difficulty in removing the glass rods from the nylon packs in a sterile manner. The most important finding was the absence of a trend toward an increased rate of contamination over time for any pack type. This indicates that when these materials are placed in covered storage in dental operatories, a 12-month storage period is not detrimental to their sterile integrity.

  19. Evaluation of polymeric materials packed in fixed bed column for oil water remediation; Avaliacao de materiais polimericos empacotados em colunas de leito fixo para a remediacao de aguas oleosas

    Energy Technology Data Exchange (ETDEWEB)

    Queiros, Yure G.C.; Barros, Cintia Chagas; Oliveira, Roberta S.; Marques, Luiz R.S.; Cunha, Luciana; Lucas, Elizabete F. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Macromoleculas Eloisa Mano], e-mail:, e-mail:


    Polymeric resins are being tried as an alternative material for treating oily waters from the petroleum industry, which have already been treated by conventional methods. The objective of this work has been to evaluate the purification degree of synthetic oily waters when treated in fixed bed columns packed with polymeric resins made up of hydrophilic and lipophilic moieties. The analysis used for characterizing the total grease and oil content (TOG) was fluorimetry. Starting oily waters of average TOG 50 ppm were prepared. Data obtained from eluted waters did not outweigh 10% of the TOG values of starting solutions in some blends of resins with a pretty good mechanical stability under the increase of pressure. Organoclay material showed a good retention performance, but has presented a mechanical instability too, compromising its use for larger amounts of wastewater. (author)

  20. Battery Pack Thermal Design

    Energy Technology Data Exchange (ETDEWEB)

    Pesaran, Ahmad


    This presentation describes the thermal design of battery packs at the National Renewable Energy Laboratory. A battery thermal management system essential for xEVs for both normal operation during daily driving (achieving life and performance) and off-normal operation during abuse conditions (achieving safety). The battery thermal management system needs to be optimized with the right tools for the lowest cost. Experimental tools such as NREL's isothermal battery calorimeter, thermal imaging, and heat transfer setups are needed. Thermal models and computer-aided engineering tools are useful for robust designs. During abuse conditions, designs should prevent cell-to-cell propagation in a module/pack (i.e., keep the fire small and manageable). NREL's battery ISC device can be used for evaluating the robustness of a module/pack to cell-to-cell propagation.

  1. Potential hydrophobic interaction between two cysteines in interior hydrophobic region improves thermostability of a family 11 xylanase from Neocallimastix patriciarum. (United States)

    You, Chun; Huang, Qiang; Xue, Huping; Xu, Yang; Lu, Hong


    In this study, we employed directed evolution and site-directed mutagenesis to screen thermostable mutants of a family 11 xylanase from Neocallimastix patriciarum, and found that the thermostability and specific activity are both enhanced when mutations (G201C and C60A) take place in the interior hydrophobic region of the enzyme. Far-ultraviolet circular dichroism analysis showed that the melting temperatures (T(m)) of the G201C and C60A-G201C mutants are higher than that of the wild type by about 10 and 12 degrees C, respectively. At 72 degrees C, their specific activities are about 4 and 6 times as that of the wild type, respectively. Homology modeling and site-directed mutagenesis demonstrated that the enhanced thermostability of the G201C and C60A-G201C mutants may be mainly attributed to a potential stronger hydrophobic interaction between the two well-packed cysteines at sites 50 and 201, rather than the disulfide bond formation which was ruled out by thiol titration with dithionitrobenzoic acid (DTNB). And the strength of such interaction depends on the packing of the side-chain and hydrophobicity of residues at these two sites. This suggests that cysteine could stabilize a protein not only by forming a disulfide bond, but also by the strong hydrophobicity itself. (c) 2009 Wiley Periodicals, Inc.

  2. The Six Pack Model

    DEFF Research Database (Denmark)

    Andersen, Henrik; Ritter, Thomas

    Ever seen a growth strategies fail because it was not connect ed to the firm’s customer base? Or a customer relationship strategy falters just because it was the wrong thing to do with that given customer? This article presents the six pack model, a tool that makes growth profitable and predictable...

  3. Computational Modelling of Particle Packing in Concrete

    NARCIS (Netherlands)

    He, H.


    Physical particle packing is becoming a hot topic in concrete technology as more and more types of granular materials are used in concrete either for ecological or for engineering purposes. Although various analytical methods have been developed for optimum mixture design, comprehensive information

  4. Numerical analysis of a SO{sub 3} packed column decomposition reactor with alloy RA 330 structural material for nuclear hydrogen production using the sulfur- iodine process

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jae Hyuk [Korea Maritime University, Busan (Korea, Republic of); Tak, Nam Il; Shin, Young Joon; Kim, Chan Soo; Lee, Ki Young [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)


    A directly heated SO{sub 3} decomposer for the sulfur-iodine and hybrid-sulfur processes has been introduced and analyzed using the computational fluid dynamics (CFD) code CFX 11. The use of a directly heated decomposition reactor in conjunction with a very high temperature reactor (VHTR) allows for higher decomposition reactor operating temperatures. However, the high temperatures and strongly corrosive operating conditions associated with SO{sub 3} decomposition present challenges for the structural materials of decomposition reactors. In order to resolve these problems, we have designed a directly heated SO{sub 3} decomposer using RA 330 alloy as a structural material and have performed a CFD analysis of the design based on the finite rate chemistry model. The CFD results show the maximum temperature of the structural material could be maintained sufficiently below 1073 K, which is considered the target temperature for RA 330. The CFD simulations also indicated good performance in terms of SO{sub 3} decomposition for the design parameters of the present study

  5. Packing defects into ordered structures

    DEFF Research Database (Denmark)

    Bechstein, R.; Kristoffersen, Henrik Høgh; Vilhelmsen, L.B.


    We have studied vicinal TiO2(110) surfaces by high-resolution scanning tunneling microscopy and density functional theory calculations. On TiO2 surfaces characterized by a high density of ⟨11̅ 1⟩ steps, scanning tunneling microscopy reveals a high density of oxygen-deficient strandlike adstructures....... With the help of density functional theory calculations we develop a complete structural model for the entire strand and demonstrate these adstructures to be more stable than an equivalent amount of bulk defects such as Ti interstitials. We argue that strands can form particularly easy on stepped surfaces...... because building material is available at step sites. The strands on TiO2(110) represent point defects that are densely packed into ordered adstructures....

  6. Packing and Disorder in Substituted Fullerenes

    KAUST Repository

    Tummala, Naga Rajesh


    Fullerenes are ubiquitous as electron-acceptor and electron-transport materials in organic solar cells. Recent synthetic strategies to improve the solubility and electronic characteristics of these molecules have translated into a tremendous increase in the variety of derivatives employed in these applications. Here, we use molecular dynamics (MD) simulations to examine the impact of going from mono-adducts to bis- and tris-adducts on the structural, cohesive, and packing characteristics of [6,6]-phenyl-C60-butyric acid methyl ester (PCBM) and indene-C60. The packing configurations obtained at the MD level then serve as input for density functional theory calculations that examine the solid-state energetic disorder (distribution of site energies) as a function of chemical substitution. The variations in structural and site-energy disorders reflect the fundamental materials differences among the derivatives and impact the performance of these materials in thin-film electronic devices.

  7. Comparison of the performance of a few packing materials designed to minimize the thermodynamic band tailing of basic compounds in reversed-phase liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Gritti, Fabrice [University of Tennessee, Knoxville (UTK); Guiochon, Georges A [ORNL


    The adsorption isotherms of phenol, caffeine, propranolol chloride, and amitriptyline chloride were measured on three new brands of C{sub 18}-bonded silica that have been designed to be more resistant than conventional C{sub 18}-bonded silica at high pHs (>8). These columns were the 4 {micro}m Bidendate Cogent-C{sub 18} (Microsolv Technology Corporation, Long Branch, NJ, USA), the 3.5 {micro}m Zorbax Extend-C{sub 18} (Agilent Technologies, Palo Alto, CA, USA), and the 5 {micro}m XTerra-C{sub 18} (Waters, Milford, MA, USA). The originality of these adsorbents is due to their surface chemistry, which protects them from rapid hydrolysis or dissolution at extreme pH conditions. Their adsorption properties were compared to those of the 3 {micro}m Luna-C{sub 18} (Phenomenex, Torrance, CA), which is a more conventional monofunctional material. The adsorption data were acquired by frontal analysis (FA) and the adsorption energy distributions (AEDs) of all systems studied were calculated by the expectation-maximization (EM) method. The experimental results show that neither a simple surface protection (Extend-C{sub 18}) nor the elimination of most of the silanol groups (Cogent-C{sub 18}) is sufficient to avoid a peak tailing of the basic compounds at pH 8 that is of thermodynamic origin. The incorporation of organic moieties in the silica matrix, which was achieved in XTerra-C{sub 18}, the first generation of hybrid methyl/silica material, reduces the silanols activity and is more successful in reducing this peak tailing.

  8. Influence of Hydrophobicity on Polyelectrolyte Complexation

    Energy Technology Data Exchange (ETDEWEB)

    Sadman, Kazi [Department; amp, Engineering, Northwestern University, Evanston, Illinois 60208, United States; Wang, Qifeng [Department; amp, Engineering, Northwestern University, Evanston, Illinois 60208, United States; Chen, Yaoyao [Department; amp, Engineering, Northwestern University, Evanston, Illinois 60208, United States; Keshavarz, Bavand [Department; Jiang, Zhang [X-ray; Shull, Kenneth R. [Department; amp, Engineering, Northwestern University, Evanston, Illinois 60208, United States


    Polyelectrolyte complexes are a fascinating class of soft materials that can span the full spectrum of mechanical properties from low viscosity fluids to glassy solids. This spectrum can be accessed by modulating the extent of electrostatic association in these complexes. However, to realize the full potential of polyelectrolyte complexes as functional materials their molecular level details need to be clearly correlated with their mechanical response. The present work demonstrates that by making simple amendments to the chain architecture it is possible to affect the salt responsiveness of polyelectrolyte complexes in a systematic manner. This is achieved by quaternizing poly(4-vinylpyridine) (QVP) with methyl, ethyl and propyl substituents– thereby increasing the hydrophobicity with increasing side chain length– and complexing them with a common anionic polyelectrolyte, poly(styrene sulfonate). The mechanical 1 ACS Paragon Plus Environment behavior of these complexes is compared to the more hydrophilic system of poly(styrene sulfonate) and poly(diallyldimethylammonium) by quantifying the swelling behavior in response to salt stimuli. More hydrophobic complexes are found to be more resistant to doping by salt, yet the mechanical properties of the complex remain contingent on the overall swelling ratio of the complex itself, following near universal swelling-modulus master curves that are quantified in this work. The rheological behavior of QVP complex coacervates are found to be approximately the same, only requiring higher salt concentrations to overcome strong hydrophobic interactions, demonstrating that hydrophobicity can be used as an important parameter for tuning the stability of polyelectrolyte complexes in general, while still preserving the ability to be processed “saloplastically”.

  9. Packing of nonoverlapping cubic particles: Computational algorithms and microstructural characteristics (United States)

    Malmir, Hessam; Sahimi, Muhammad; Tabar, M. Reza Rahimi


    Packing of cubic particles arises in a variety of problems, ranging from biological materials to colloids and the fabrication of new types of porous materials with controlled morphology. The properties of such packings may also be relevant to problems involving suspensions of cubic zeolites, precipitation of salt crystals during CO2 sequestration in rock, and intrusion of fresh water in aquifers by saline water. Not much is known, however, about the structure and statistical descriptors of such packings. We present a detailed simulation and microstructural characterization of packings of nonoverlapping monodisperse cubic particles, following up on our preliminary results [H. Malmir et al., Sci. Rep. 6, 35024 (2016), 10.1038/srep35024]. A modification of the random sequential addition (RSA) algorithm has been developed to generate such packings, and a variety of microstructural descriptors, including the radial distribution function, the face-normal correlation function, two-point probability and cluster functions, the lineal-path function, the pore-size distribution function, and surface-surface and surface-void correlation functions, have been computed, along with the specific surface and mean chord length of the packings. The results indicate the existence of both spatial and orientational long-range order as the the packing density increases. The maximum packing fraction achievable with the RSA method is about 0.57, which represents the limit for a structure similar to liquid crystals.

  10. ExactPack Documentation

    Energy Technology Data Exchange (ETDEWEB)

    Singleton, Robert Jr. [Los Alamos National Laboratory; Israel, Daniel M. [Los Alamos National Laboratory; Doebling, Scott William [Los Alamos National Laboratory; Woods, Charles Nathan [Los Alamos National Laboratory; Kaul, Ann [Los Alamos National Laboratory; Walter, John William Jr [Los Alamos National Laboratory; Rogers, Michael Lloyd [Los Alamos National Laboratory


    For code verification, one compares the code output against known exact solutions. There are many standard test problems used in this capacity, such as the Noh and Sedov problems. ExactPack is a utility that integrates many of these exact solution codes into a common API (application program interface), and can be used as a stand-alone code or as a python package. ExactPack consists of python driver scripts that access a library of exact solutions written in Fortran or Python. The spatial profiles of the relevant physical quantities, such as the density, fluid velocity, sound speed, or internal energy, are returned at a time specified by the user. The solution profiles can be viewed and examined by a command line interface or a graphical user interface, and a number of analysis tools and unit tests are also provided. We have documented the physics of each problem in the solution library, and provided complete documentation on how to extend the library to include additional exact solutions. ExactPack’s code architecture makes it easy to extend the solution-code library to include additional exact solutions in a robust, reliable, and maintainable manner.

  11. Cell packing structures

    KAUST Repository

    Pottmann, Helmut


    This paper is an overview of architectural structures which are either composed of polyhedral cells or closely related to them. We introduce the concept of a support structure of such a polyhedral cell packing. It is formed by planar quads and obtained by connecting corresponding vertices in two combinatorially equivalent meshes whose corresponding edges are coplanar and thus determine planar quads. Since corresponding triangle meshes only yield trivial structures, we focus on support structures associated with quad meshes or hex-dominant meshes. For the quadrilateral case, we provide a short survey of recent research which reveals beautiful relations to discrete differential geometry. Those are essential for successfully initializing numerical optimization schemes for the computation of quad-based support structures. Hex-dominant structures may be designed via Voronoi tessellations, power diagrams, sphere packings and various extensions of these concepts. Apart from the obvious application as load-bearing structures, we illustrate here a new application to shading and indirect lighting. On a higher level, our work emphasizes the interplay between geometry, optimization, statics, and manufacturing, with the overall aim of combining form, function and fabrication into novel integrated design tools.

  12. Thermo-super-hydrophobic effect (United States)

    Floryan, Jerzy M.


    Super-hydrophobic effect involves capture of gas bubbles in pores of solid wall. These bubbles separate moving liquid from the solid surface resulting in a substantial reduction of shear drag experienced by the liquid. The super-hydrophobic effect requires presence of two phases and thus drag reduction can be accomplished only for liquids. Thermo-super-hydrophobic effect takes advantage of the localized heating to create separation bubbles and thus can work with single phase flow systems. Analysis of a simple model problem shows that this effect is very strong in the case of small Re flows such as those found in micro-channels and can reduce pressure drop down to 50% of the reference value if the heating pattern as well as the heating intensity are suitable chosen. The thermo-super-hydrophobic effect becomes marginal when Re increases above a certain critical value.

  13. Hydrophobic repulsion and its origin


    Schlesinger, Itai; Sivan, Uri


    The fundamental role of hydrophobic interactions in nature and technology has motivated decades long research aimed at measuring the distance-dependent hydrophobic force and identifying its origin. This quest has nevertheless proved more elusive than anticipated and the nature of the interaction at distances shorter than 2-3 nanometers, or even its sign, have never been conclusively determined. Employing an ultra-high resolution frequency-modulation atomic force microscope (FM-AFM) we succeed...

  14. Wear resistance of hydrophobic surfaces (United States)

    Martinez, MA; Abenojar, J.; Pantoja, M.; López de Armentia, S.


    Nature has been an inspiration source to develop artificial hydrophobic surfaces. During the latest years the development of hydrophobic surfaces has been widely researched due to their numerous ranges of industrial applications. Industrially the use of hydrophobic surfaces is being highly demanded. This is why many companies develop hydrophobic products to repel water, in order to be used as coatings. Moreover, these coating should have the appropriated mechanical properties and wear resistance. In this work wear study of a hydrophobic coating on glass is carried out. Hydrophobic product used was Sika Crystal Dry by Sika S.A.U. (Alcobendas, Spain). This product is currently used on car windshield. To calculate wear resistance, pin-on-disk tests were carried out in dry and water conditions. The test parameters were rate, load and sliding distance, which were fixed to 60 rpm, 5 N and 1000 m respectively. A chamois was used as pin. It allows to simulate a real use. The friction coefficient and loss weight were compared to determinate coating resistance

  15. Laboratory Investigation of the Hydrophobicity Transfer Mechanism on Composite Insulators Aged in Coastal Service


    N. Mavrikakis; K. Siderakis; Koudoumas, E.; Drakakis, E.; Kymakis, E


    Silicone rubber (SIR) insulators are known to maintain their surface hydrophobicity even under severe pollution conditions in contrast to the other composite insulator materials used at the last decades. This critical advantage of silicone rubber insulators has made them dominant in high voltage power systems despite the fact that there are other composite materials with better static hydrophobicity. In service conditions, priority is given to the dynamic performance of hydrophobicity due to ...

  16. MP:PD--a data base of internal packing densities, internal packing defects and internal waters of helical membrane proteins. (United States)

    Rose, Alexander; Theune, Dominic; Goede, Andrean; Hildebrand, Peter W


    The membrane protein packing database (MP:PD) ( is a database of helical membrane proteins featuring internal atomic packing densities, cavities and waters. Membrane proteins are not tightly packed but contain a considerable number of internal cavities that differ in volume, polarity and solvent accessibility as well as in their filling with internal water. Internal cavities are supposed to be regions of high physical compressibility. By serving as mobile hydrogen bonding donors or acceptors, internal waters likely facilitate transition between different functional states. Despite these distinct functional roles, internal cavities of helical membrane proteins are not well characterized, mainly because most internal waters are not resolved by crystal structure analysis. Here we combined various computational biophysical techniques to characterize internal cavities, reassign positions of internal waters and calculate internal packing densities of all available helical membrane protein structures and stored them in MP:PD. The database can be searched using keywords and entries can be downloaded. Each entry can be visualized in Provi, a Jmol-based protein viewer that provides an integrated display of low energy waters alongside membrane planes, internal packing density, hydrophobic cavities and hydrogen bonds.

  17. Surfactant Facilitated Spreading of Aqueous Drops on Hydrophobic Surfaces (United States)

    Kumar, Nitin; Couzis, Alex; Maldareili, Charles; Singh, Bhim (Technical Monitor)


    removes a significant amount of the surface water. In this presentation, we report the results of measurements of the molecular packing and rates of kinetic exchange of the trisiloxane surfactants at the air/water interface in order to confirm our picture of trisiloxane packing, and provide additional insight into the superspreading process. We used the pendant bubble technique as a Langmuir trough to measure the trisiloxane equation of state which relates the tension to the surface concentration. From these measurements we obtain accurate values for the maximum packing density. We find that trisiloxanes with 4 and 8 ethoxylate groups have the same maximum packing concentration, indicating that the maximum packing is controlled by the cross section of the head group. For trisiloxanes with larger than eight ethoxylates, the maximum packing increases with ethoxylate number, indicating that the disposition of the ethoxylate chain (i.e., its effective size) is controlling. This supports our picture of superspreading: The superspreading ability of trisiloxanes decreases considerably for trisiloxanes with larger than eight ethoxylates; the packing measurements indicate that for the higher ethoxylate number trisiloxanes, the compact nonpolar head groups are pushed apart by the ethoxylate chain. They leave spaces of surface water on adsorption and do not lower the solid tension as much as their lower chain analogues. Finally the report measurements of the dynamic tension reduction accompanying the adsorption of trisiloxanes onto an initially clean interface using the pendant bubble technique, and we obtain from these relaxations, the equation of state and a mass transfer model, the rate constants for kinetic exchange. We find that the rate constants for desorption of trisiloxanes are generally much slower than for analogous aliphatic polyethoxylate surfactants with identical ethoxylate chain lengths. When an aqueous drop of a superspreader solution is placed on a hydrophobic

  18. Polarizable protein packing

    KAUST Repository

    Ng, Albert H.


    To incorporate protein polarization effects within a protein combinatorial optimization framework, we decompose the polarizable force field AMOEBA into low order terms. Including terms up to the third-order provides a fair approximation to the full energy while maintaining tractability. We represent the polarizable packing problem for protein G as a hypergraph and solve for optimal rotamers with the FASTER combinatorial optimization algorithm. These approximate energy models can be improved to high accuracy [root mean square deviation (rmsd) < 1 kJ mol -1] via ridge regression. The resulting trained approximations are used to efficiently identify new, low-energy solutions. The approach is general and should allow combinatorial optimization of other many-body problems. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011 Copyright © 2011 Wiley Periodicals, Inc.

  19. Inverse colloidal crystal membranes for hydrophobic interaction membrane chromatography. (United States)

    Vu, Anh T; Wang, Xinying; Wickramasinghe, S Ranil; Yu, Bing; Yuan, Hua; Cong, Hailin; Luo, Yongli; Tang, Jianguo


    Hydrophobic interaction membrane chromatography has gained interest due to its excellent performance in the purification of humanized monoclonal antibodies. The membrane material used in hydrophobic interaction membrane chromatography has typically been commercially available polyvinylidene fluoride. In this contribution, newly developed inverse colloidal crystal membranes that have uniform pores, high porosity and, therefore, high surface area for protein binding are used as hydrophobic interaction membrane chromatography membranes for humanized monoclonal antibody immunoglobulin G purification. The capacity of the inverse colloidal crystal membranes developed here is up to ten times greater than commercially available polyvinylidene fluoride membranes with a similar pore size. This work highlights the importance of developing uniform pore size high porosity membranes in order to maximize the capacity of hydrophobic interaction membrane chromatography. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Softening of stressed granular packings with resonant sound waves. (United States)

    Reichhardt, C J Olson; Lopatina, L M; Jia, X; Johnson, P A


    We perform numerical simulations of a two-dimensional bidisperse granular packing subjected to both a static confining pressure and a sinusoidal dynamic forcing applied by a wall on one edge of the packing. We measure the response experienced by a wall on the opposite edge of the packing and obtain the resonant frequency of the packing as the static or dynamic pressures are varied. Under increasing static pressure, the resonant frequency increases, indicating a velocity increase of elastic waves propagating through the packing. In contrast, when the dynamic amplitude is increased for fixed static pressure, the resonant frequency decreases, indicating a decrease in the wave velocity. This occurs both for compressional and for shear dynamic forcing and is in agreement with experimental results. We find that the average contact number Zc at the resonant frequency decreases with increasing dynamic amplitude, indicating that the elastic softening of the packing is associated with a reduced number of grain-grain contacts through which the elastic waves can travel. We image the excitations created in the packing and show that there are localized disturbances or soft spots that become more prevalent with increasing dynamic amplitude. Our results are in agreement with experiments on glass bead packings and earth materials such as sandstone and granite and may be relevant to the decrease in elastic wave velocities that has been observed to occur near fault zones after strong earthquakes, in surficial sediments during strong ground motion, and in structures during earthquake excitation.

  1. Packing parameters effect on injection molding of polypropylene nanostructured surfaces

    DEFF Research Database (Denmark)

    Calaon, Matteo; Tosello, Guido; Hansen, Hans Nørgaard


    In today´s industry, applications involving surface patterning of sub-μm to nanometer scale structures have shown a high growth potential. To investigate the injection molding capability of replicating sub-μm surface texture on a large scale area, a 30x80 mm2 tool insert with surface structures...... having a diameter of 500 nm was employed. The tool insert surface was produced using chemical-based-batch techniques such aluminum anodization and nickel electroplating. During the injection molding process, polypropylene (PP) was employed as material and packing phase parameters (packing time, packing...

  2. Fluid model for a partially packed dielectric barrier discharge plasma reactor (United States)

    Gadkari, Siddharth; Tu, Xin; Gu, Sai


    In this work, a two-dimensional numerical fluid model is developed for a partially packed dielectric barrier discharge (DBD) in pure helium. Influence of packing on the discharge characteristics is studied by comparing the results of DBD with partial packing with those obtained for DBD with no packing. In the axial partial packing configuration studied in this work, the electric field strength was shown to be enhanced at the top surface of the spherical packing material and at the contact points between the packing and the dielectric layer. For each value of applied potential, DBD with partial packing showed an increase in the number of pulses in the current profile in the positive half cycle of the applied voltage, as compared to DBD with no packing. Addition of partial packing to the plasma-alone DBD also led to an increase in the electron and ion number densities at the moment of breakdown. The time averaged electron energy profiles showed that a much higher range of electron energy can be achieved with the use of partial packing as compared to no packing in a DBD, at the same applied power. The spatially and time averaged values over one voltage cycle also showed an increase in power density and electron energy on inclusion of partial packing in the DBD. For the applied voltage parameters studied in this work, the discharge was found to be consistently homogeneous and showed the characteristics of atmospheric pressure glow discharge.

  3. Bioconcentration factor hydrophobicity cutoff: an artificial phenomenon reconstructed. (United States)

    Jonker, Michiel T O; Van der Heijden, Stephan A


    The debate on whether highly hydrophobic organic chemicals (with log Kow > 5-6) bioconcentrate less than may be expected from their hydrophobicity is still not settled. The often-observed hydrophobicity "cutoff" might either be explained by artifacts occurring during bioconcentration factor (BCF) measurements or by a true mechanism, i.e., reduced uptake of larger molecules due to decreased membrane permeation. In this paper, we advocate there is no hydrophobicity cutoff, at least not for compounds with log Kow of up to 7.5. Data are presented on the uptake of polycyclic aromatic hydrocarbons (PAHs) in the aquatic worm Lumbriculus variegatus. For this combination of chemicals/organism, BCFs were measured using several approaches, including traditional batch uptake kinetics measurements and alternative ones, involving solid-phase microextraction (SPME), polyoxymethylene solid-phase extraction (POM-SPE), field exposures, and the substitution of living worms by dead worm material or liposomes. A hydrophobicity cutoff was observed at two levels during the traditional approach only, whereas for the other approaches it was absent. The data were used to demonstrate the presence and impact of artifacts due to so-called "third phase effects" and nonequilibrium conditions that can obscure "true uptake". The experiments suggest that previously observed cutoff effects can be ascribed to artifacts, and that current risk assessment (often incorporating a BCF cutoff) as well as BCF measurement techniques of very hydrophobic chemicals should be revised.


    Directory of Open Access Journals (Sweden)



    Full Text Available Septoplasty is one of the most commonly performed surgeries in rhinology to relieve nasal obstruction of patients with distortion in the midline cartilage or septum of the nose to relieve nasal obstruction of patient and findings consistent with nasal endoscopy. The anterior nasal packing routinely done following septoplasty is usually conventional and not evidence based. The purpose of nasal packing is to obtain haemostasis, enhance opposition of septal flaps, avoid septal haematoma formation, close the dead space, avoid synechiae formation, provide support to septal cartilage and prevent its displacement. OBJECTIVE This study intends to evaluate the effects of nasal packing on surgical success and related complications in septoplasty. MATERIALS AND METHODS The present clinical prospective and randomised study was carried out on patients attending Otorhinolaryngology Department of Santhiram Medical College & General Hospital between March 2012 and March 2015. Patients undergoing septoplasty were randomised either to receive anterior nasal packing or to not receive nasal packing postoperatively. RESULTS Levels of pain experienced by patients with nasal packing postoperatively during the initial 24 hours postoperatively and during the removal of the pack were significantly more. Post-operative headache, epiphora, swallowing discomfort and sleep disturbance were more in patients with nasal packing and statistically (p.05. Septal haematoma, adhesions and local infections in both groups were statistically insignificant (p>.05. CONCLUSION Septoplasty enhances the standard of living of patients with septal deviation and nasal obstruction. Our study results suggest that nasal packing after septoplasty is not obligatory. Nasal packing causes considerably more pain and complications, and it should be reserved only for those who have bleeding predisposition.

  5. Discrete element modelling of pebble packing in pebble bed reactors

    Energy Technology Data Exchange (ETDEWEB)

    Suikkanen, Heikki, E-mail:; Ritvanen, Jouni, E-mail:; Jalali, Payman, E-mail:; Kyrki-Rajamäki, Riitta, E-mail:


    Highlights: • A discrete element method code is developed for pebble bed reactor analyses. • Methods are established to extract packing information at various spatial scales. • Packing simulations inside annular core geometry are done varying input parameters. • The restitution coefficient has the strongest effect on the resulting packing density. • Detailed analyses reveal local densification especially near the walls. - Abstract: It is important to understand the packing characteristics and behaviour of the randomly packed pebble bed to further analyse the reactor physical and thermal-hydraulic behaviour and to design a safe and economically feasible pebble bed reactor. The objective of this work was to establish methods to model and analyse the pebble packing in detail to provide useful tools and data for further analyses. Discrete element method (DEM) is a well acknowledged method for analysing granular materials, such as the fuel pebbles in a pebble bed reactor. In this work, a DEM computer code was written specifically for pebble bed analyses. Analysis methods were established to extract data at various spatial scales from the pebble beds resulting from the DEM simulations. A comparison with available experimental data was performed to validate the DEM implementation. To test the code implementation in full-scale reactor calculations, DEM packing simulations were done in annular geometry with 450,000 pebbles. Effects of the initial packing configuration, friction and restitution coefficients and pebble size distribution to the resulting pebble bed were investigated. The packing simulations revealed that from the investigated parameters the restitution coefficient had the largest effect on the resulting average packing density while other parameters had smaller effects. Detailed local packing density analysis of pebble beds with different average densities revealed local variations especially strong in the regions near the walls. The implemented DEM

  6. Condensation in Nanoporous Packed Beds. (United States)

    Ally, Javed; Molla, Shahnawaz; Mostowfi, Farshid


    In materials with tiny, nanometer-scale pores, liquid condensation is shifted from the bulk saturation pressure observed at larger scales. This effect is called capillary condensation and can block pores, which has major consequences in hydrocarbon production, as well as in fuel cells, catalysis, and powder adhesion. In this study, high pressure nanofluidic condensation studies are performed using propane and carbon dioxide in a colloidal crystal packed bed. Direct visualization allows the extent of condensation to be observed, as well as inference of the pore geometry from Bragg diffraction. We show experimentally that capillary condensation depends on pore geometry and wettability because these factors determine the shape of the menisci that coalesce when pore filling occurs, contrary to the typical assumption that all pore structures can be modeled as cylindrical and perfectly wetting. We also observe capillary condensation at higher pressures than has been done previously, which is important because many applications involving this phenomenon occur well above atmospheric pressure, and there is little, if any, experimental validation of capillary condensation at such pressures, particularly with direct visualization.

  7. Impact of particle nanotopology on water transport through hydrophobic soils. (United States)

    Truong, Vi Khanh; Owuor, Elizabeth A; Murugaraj, Pandiyan; Crawford, Russell J; Mainwaring, David E


    The impact of non- and poorly wetting soils has become increasingly important, due to its direct influence on the water-limited potential yield of rain-fed grain crops at a time of enhanced global competition for fresh water. This study investigates the physical and compositional mechanisms underlying the influence of soil organic matter (SOM) on the wetting processes of model systems. These model systems are directly related to two sandy wheat-producing soils that have contrasting hydrophobicities. Atomic force microscopy (AFM), contact angle and Raman micro-spectroscopy measurements on model planar and particulate SOM-containing surfaces demonstrated the role of the hierarchical surface structure on the wetting dynamics of packed particulate beds. It was found that a nanoscale surface topology is superimposed over the microscale roughness of the packed particles, and this controls the extent of water ingress into particulate packed beds of these particles. Using two of the dominant component organic species found in the SOM of the two soils used in this study, it was found that the specific interactions taking place between the SOM components, rather than their absolute quantities, dictated the formation of highly hydrophobic surface nanotopologies. This hydrophobicity was demonstrated, using micro-Raman imaging, to arise from the surface being in a composite Cassie-Baxter wetting state. Raman imaging demonstrated that the particle surface nanotopography influenced the degree of air entrapment in the interstices within the particle bed. The influence of a conventional surfactant on the wetting kinetics of both the model planar surfaces and packed particulate beds was quantified in terms of their respective advancing contact angles and the capillary wetting force vector. The information obtained for all of the planar and particulate surfaces, together with that obtained for the two soils, allowed linear relationships to be obtained in plots of the contact angle

  8. Domain Discretization and Circle Packings

    DEFF Research Database (Denmark)

    Dias, Kealey

    , and the edges are geodesic segments (Euclidean, hyperbolic, or spherical) connecting centers of circles that are tangent to each other. Three circles that are mutually tangent form a face of the triangulation. Since circle packing is closely related to triangulation, circle packing methods can be applied...... to domain discretization problems such as triangulation and unstructured mesh generation techniques. We wish to ask ourselves the question: given a cloud of points in the plane (we restrict ourselves to planar domains), is it possible to construct a circle packing preserving the positions of the vertices...

  9. Strong, reversible underwater adhesion via gecko-inspired hydrophobic fibers. (United States)

    Soltannia, Babak; Sameoto, Dan


    Strong, reversible underwater adhesion using gecko-inspired surfaces is achievable through the use of a hydrophobic structural material and does not require surface modification or suction cup effects for this adhesion to be effective. Increased surface energy can aid in dry adhesion in an air environment but strongly degrades wet adhesion via reduction of interfacial energy underwater. A direct comparison of structurally identical but chemically different mushroom shaped fibers shows that strong, reversible adhesion, even in a fully wetted, stable state, is feasible underwater if the structural material of the fibers is hydrophobic and the mating surface is not strongly hydrophilic. The exact adhesion strength will be a function of the underwater interfacial energy between surfaces and the specific failure modes of individual fibers. This underwater adhesion has been calculated to be potentially greater than the dry adhesion for specific combinations of hydrophobic surfaces.

  10. Hydrophobic Calcium Carbonate for Cement Surface

    Directory of Open Access Journals (Sweden)

    Shashi B. Atla


    Full Text Available This report describes a novel way to generate a highly effective hydrophobic cement surface via a carbonation route using sodium stearate. Carbonation reaction was carried out at different temperatures to investigate the hydrophobicity and morphology of the calcium carbonate formed with this process. With increasing temperatures, the particles changed from irregular shapes to more uniform rod-like structures and then aggregated to form a plate-like formation. The contact angle against water was found to increase with increasing temperature; after 90 °C there was no further increase. The maximum contact angle of 129° was obtained at the temperature of 60 °C. It was also found that carbonation increased the micro hardness of the cement material. The micro hardness was found to be dependent on the morphology of the CaCO3 particles. The rod like structures which caused increased mineral filler produced a material with enhanced strength. The 13C cross polarization magic-angle spinning NMR spectra gave plausible explanation of the interaction of organic-inorganic moieties.

  11. The pursuit of perfect packing

    CERN Document Server

    Weaire, Denis


    Coauthored by one of the creators of the most efficient space packing solution, the Weaire-Phelan structure, The Pursuit of Perfect Packing, Second Edition explores a problem of importance in physics, mathematics, chemistry, biology, and engineering: the packing of structures. Maintaining its mathematical core, this edition continues and revises some of the stories from its predecessor while adding several new examples and applications. The book focuses on both scientific and everyday problems ranging from atoms to honeycombs. It describes packing models, such as the Kepler conjecture, Voronoï decomposition, and Delaunay decomposition, as well as actual structure models, such as the Kelvin cell and the Weaire-Phelan structure. The authors discuss numerous historical aspects and provide biographical details on influential contributors to the field, including emails from Thomas Hales and Ken Brakke. With examples from physics, crystallography, engineering, and biology, this accessible and whimsical bo...

  12. High performance hydrophobic solvent, carbon dioxide capture (United States)

    Nulwala, Hunaid; Luebke, David


    Methods and compositions useful, for example, for physical solvent carbon capture. A method comprising: contacting at least one first composition comprising carbon dioxide with at least one second composition to at least partially dissolve the carbon dioxide of the first composition in the second composition, wherein the second composition comprises at least one siloxane compound which is covalently modified with at least one non-siloxane group comprising at least one heteroatom. Polydimethylsiloxane (PDMS) materials and ethylene-glycol based materials have high carbon dioxide solubility but suffer from various problems. PDMS is hydrophobic but suffers from low selectivity. Ethylene-glycol based systems have good solubility and selectivity, but suffer from high affinity to water. Solvents were developed which keep the desired combinations of properties, and result in a simplified, overall process for carbon dioxide removal from a mixed gas stream.

  13. Incorporation of Certain Hydrophobic Excipients in the Core of Melt ...

    African Journals Online (AJOL)

    Purpose: A process of melt granulation whereby the drug powder is mixed with a melted wax has been used to modify the dissolution rates of drug particles. The present study investigated how the incorporation of hydrophobic materials (talc or magnesium stearate) in the core of such granules may further retard drug ...

  14. The mechanical behaviour of packed particulates

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, R


    Within the Canadian Nuclear Fuel Waste Management program, the central concept is to package used fuel in containers that would be deposited in an underground vault in a plutonic rock formation. To provide internal mechanical support for the container, the reference design specifies it to be filled with a matrix of compacted particulate material (called 'packed particulate'), such as quartz sand granules. The focus of this report is on the mechanical properties of the packed-particulate material, based on information drawn from the extant literature. We first consider the packing density of particulate matrices to minimize the remnant porosity and maximize mechanical stability under conditions of external pressure. Practical methods, involving vibratory packing, are reviewed and recommendations made to select techniques to achieve optimum packing density. The behaviour of particulates under compressive loading has been of interest to the powder metallurgy industry (i.e., the manufacture of products from pressed/sintered metal and ceramic powders) since the early decades of this century. We review the evidence showing that in short timescales, stress induced compaction occurs by particle shuffling and rearrangement, elastic distortion, plastic yielding and microfracturing. Analytical expressions are available to describe these processes in a semiquantitative fashion. Time-dependent compaction, mainly via creep mechanisms, is more complex. Much of the theoretical and experimental information is confined to higher temperatures (> 500 degrees C), where deformation rates are more rapid. Thus, for the relatively low ambient temperatures of the waste container ({approx}100 degrees C), we require analytical techniques to extrapolate the collective particulate creep behaviour. This is largely accomplished by employing current theories of creep deformation, particularly in the form of Deformation Mechanism Maps, which allow estimation of creep rates over a wide

  15. FY-87 packing fabrication techniques (commercial waste form) results

    Energy Technology Data Exchange (ETDEWEB)

    Werry, E.V.; Gates, T.E.; Cabbage, K.S.; Eklund, J.D.


    This report covers the investigation of fabrication techniques associated with the development of suitable materials and methods to provide a prefabricated packing for waste packages for the Basalt Waste Isolation Project (BWIP). The principal functions of the packing are to minimize container corrosion during the 300 to 1000 years following repository closure and provide long-term control of the release of radionuclides from the waste package. The investigative work, discussed in this report, was specifically conceived to develop the design criteria for production of full-scale prototypical packing rings. The investigative work included the preparation of procedures, the preparation of fabrication materials, physical properties, and the determination of the engineering properties. The principal activities were the preparation of the materials and the determination of the physical properties. 21 refs., 20 figs., 14 tabs.

  16. Hydrodynamic impact of particle shape in slurry packed liquid chromatography columns

    DEFF Research Database (Denmark)

    Lottes, F.; Arlt, W.; Minceva, M.


    for visualization of the inner part of a packed column and measurement of the spatial resolved column packing properties. For evaluation of the influence of the particle shape on the velocity distribution and column performance, irregular and spherical reversed phases were studied in detail. The results showed...... a decreasing velocity towards the column wall most certainly due to a lower permeability. This effect was much less pronounced in the case of spherical particles, indicating a more homogenous packing structure. The influence of the column packing pressure, as a possible measure for improvement of the packing...... homogeneity was also studied. It was shown that under the same packing conditions spherical particles always lead to a more homogeneous packing. The overall results of this work contribute to the origin of the fact that spherical material is superior to irregular one from the hydrodynamic point of view....

  17. Substituent effect on the thermodynamic solubility of structural analogs: relative contribution of crystal packing and hydration. (United States)

    Ozaki, Shunsuke; Nakagawa, Yoshiaki; Shirai, Osamu; Kano, Kenji


    Thermodynamic analysis of the solubility of benzoylphenylurea (BPU) derivatives was conducted to investigate the relative importance of crystal packing and hydration for improving solubility with minor structural modification. The contribution of crystal packing to solubility was evaluated from the change in Gibbs energy on the transition from the crystalline to liquid state. Hydration Gibbs energy was estimated using a linear free-energy relationship between octanol-water partition coefficients and gas-water partition coefficients. The established solubility model satisfactorily explained the relative thermodynamic solubility of the model compounds and revealed that crystal packing and hydration equally controlled solubility of the structural analogs. All hydrophobic substituents were undesirable for solubility in terms of hydration, as expected. On the other hand, some of these hydrophobic substituents destabilized crystal packing and improved the solubility of the BPU derivatives when their impact on crystal packing exceeded their negative influence on hydration. The replacement of a single substituent could cause more than a 10-fold enhancement in thermodynamic solubility; this degree of improvement was comparable to that generally achieved by amorphous formulations. Detailed analysis of thermodynamic solubility will allow us to better understand the true substituent effect and design drug-like candidates efficiently. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  18. GUMBOS matrices of variable hydrophobicity for matrix-assisted laser desorption/ionization mass spectrometry. (United States)

    Al Ghafly, Hashim; Siraj, Noureen; Das, Susmita; Regmi, Bishnu P; Magut, Paul K S; Galpothdeniya, Waduge Indika S; Murray, Kermit K; Warner, Isiah M


    Detection of hydrophobic peptides remains a major obstacle for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). This stems from the fact that most matrices for MALDI are hydrophilic and therefore have low affinities for hydrophobic peptides. Herein, 1-aminopyrene (AP) and AP-derived group of uniform materials based on organic salts (GUMBOS) as novel matrices for MALDI-MS analyses of peptides were investigated for hydrophobic and hydrophilic peptides. A number of solid-phase AP-based GUMBOS are synthesized with variable hydrophobicity simply by changing the counterions. Structures were confirmed by use of (1)H NMR and electrospray ionization mass spectrometry (ESI-MS). 1-Octanol/water partition coefficients (Ko/w) were used to measure the hydrophobicity of the matrices. A dried-droplet method was used for sample preparation. All spectra were obtained using a MALDI-TOF mass spectrometer in positive ion reflectron mode. A series of AP-based GUMBOS was synthesized including [AP][chloride] ([AP][Cl]), [AP][ascorbate] ([AP][Asc]) and [AP][bis(trifluoromethane)sulfonimide] ([AP][NTf2]). The relative hydrophobicities of these compounds and α-cyano-4-hydroxycinnamic acid (CHCA, a common MALDI matrix) indicated that AP-based GUMBOS can be tuned to be much more hydrophobic than CHCA. A clear trend is observed between the signal intensities of hydrophobic peptides and hydrophobicity of the matrix. MALDI matrices of GUMBOS with tunable hydrophobicities are easily obtained simply by varying the counterion. We have found that hydrophobic matrix materials are very effective for MALDI determination of hydrophobic peptides and, similarly, the more hydrophilic peptides displayed greater intensity in the more hydrophilic matrix. Copyright © 2014 John Wiley & Sons, Ltd.

  19. Antibacterial activity and the hydrophobicity of cotton coated with hexadecyltrimethoxysilane (United States)

    Rohaeti, Eli; Rakhmawati, Anna


    In this work, cotton fiber was fabricated using silver nanoparticles to produce hydrophobic and antibacterial material. The silver nanoparticle was prepared with chemical reduction method using trisodium citrate as reducing agent and PVA as stabilizer. Silver nanoparticle was deposited on cotton fibers as antibacterial agent and HDTMS 4% v/v was coated on those as hydrophobic agent. The cotton fibers before and after modification were characterized its functional groups, contact angles, and antibacterials activities. The functional groups of cottons were determined by using ATR-FTIR, hydrophobic properties of cottons were determined by measuring contact angle, and antibacterial activities of cottons were determined by measuring clear zone. The addition of HDTMS decreased the intensity of absorption bands of functional groups but increased contact angle of cotton cloth. The cotton cloth-silver nanoparticle shows the highest antibacterial properties. The antibacterial activity of cotton cloth without and with modification against Staphylococcus aureus ATCC 25923 and Eschericia coli 32518 were significantly different.

  20. Tuning the hydrophobicity of ZSM-5 zeolites by surface silanization using alkyltrichlorosilane

    Energy Technology Data Exchange (ETDEWEB)

    Han Xiaolong; Wang Lei [State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China); Li Jiding, E-mail: [State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China); Zhan Xia; Chen Jian; Yang Jichu [State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China)


    ZSM-5 zeolites were modified with alkyltrichlorosilanes of various chain lengths (octyltrichlorosilane, decyltrichlorosilane, dodecyltrichlorosilane and hexadecyltrichlorosilane) and characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Thermal gravimetric analysis (TGA) and contact angle measurements (CA). The results showed that a closely packed and hydrophobic layer was presented at the particles surface and the surface wetting property varied from hydrophilic to hydrophobic, even to superhydrophobic. It was interesting to notice that the hydrophobic properties of modified ZSM-5 particles could be tuned by varying the chain length of chlorosilane and changing the pretreatment temperature before silanization. With increasing the alkyl chain length of trichlorosilane, the hydrophobicity increased. However, with an increase in the pretreatment temperature, the hydrophobicity decreased. Moreover, the relationship between the wetting properties and thermal stability was also investigated, the results showed that the modified ZSM-5 particles possessed good hydrophobicity at a temperature below 250 deg. C in air. These modified ZSM-5 particles may be utilized for many potential applications, such as membrane fillers, selective adsorbents, catalysts, chromatographic supports and so on.

  1. Tuning the hydrophobicity of ZSM-5 zeolites by surface silanization using alkyltrichlorosilane (United States)

    Han, Xiaolong; Wang, Lei; Li, Jiding; Zhan, Xia; Chen, Jian; Yang, Jichu


    ZSM-5 zeolites were modified with alkyltrichlorosilanes of various chain lengths (octyltrichlorosilane, decyltrichlorosilane, dodecyltrichlorosilane and hexadecyltrichlorosilane) and characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Thermal gravimetric analysis (TGA) and contact angle measurements (CA). The results showed that a closely packed and hydrophobic layer was presented at the particles surface and the surface wetting property varied from hydrophilic to hydrophobic, even to superhydrophobic. It was interesting to notice that the hydrophobic properties of modified ZSM-5 particles could be tuned by varying the chain length of chlorosilane and changing the pretreatment temperature before silanization. With increasing the alkyl chain length of trichlorosilane, the hydrophobicity increased. However, with an increase in the pretreatment temperature, the hydrophobicity decreased. Moreover, the relationship between the wetting properties and thermal stability was also investigated, the results showed that the modified ZSM-5 particles possessed good hydrophobicity at a temperature below 250 °C in air. These modified ZSM-5 particles may be utilized for many potential applications, such as membrane fillers, selective adsorbents, catalysts, chromatographic supports and so on.

  2. Deterministic indexing for packed strings

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Skjoldjensen, Frederik Rye


    Given a string S of length n, the classic string indexing problem is to preprocess S into a compact data structure that supports efficient subsequent pattern queries. In the deterministic variant the goal is to solve the string indexing problem without any randomization (at preprocessing time...... or query time). In the packed variant the strings are stored with several character in a single word, giving us the opportunity to read multiple characters simultaneously. Our main result is a new string index in the deterministic and packed setting. Given a packed string S of length n over an alphabet σ......, we show how to preprocess S in O(n) (deterministic) time and space O(n) such that given a packed pattern string of length m we can support queries in (deterministic) time O (m/α + log m + log log σ), where α = w/log σ is the number of characters packed in a word of size w = θ(log n). Our query time...

  3. Hydrophobic-Core Microcapsules and Their Formation (United States)

    Calle, Luz M. (Inventor); Li, Wenyan (Inventor); Buhrow, Jerry W. (Inventor); Jolley, Scott T. (Inventor)


    Hydrophobic-core microcapsules and methods of their formation are provided. A hydrophobic-core microcapsule may include a shell that encapsulates a hydrophobic substance with a core substance, such as dye, corrosion indicator, corrosion inhibitor, and/or healing agent, dissolved or dispersed therein. The hydrophobic-core microcapsules may be formed from an emulsion having hydrophobic-phase droplets, e.g., containing the core substance and shell-forming compound, dispersed in a hydrophilic phase. The shells of the microcapsules may be capable of being broken down in response to being contacted by an alkali, e.g., produced during corrosion, contacting the shell.

  4. Food packing optimization (United States)

    The development of a universal closure lid for the space shuttle food package is reported. The revised lid needs a folded configuration which, when unfolded, fully conforms to the interior surfaces of the food cup. Experimental thermoform molds were fabricated and test lids formed. The lid material not in contact with the food conformed to the cup interior without wrinkles, permitting full nesting of the cups. The final lid design was established and thermoform tooling designed and fabricated. Lids formed on these molds were tested for strength. The heating elements were replaced and repositioned to eliminate any hot spots which may cause warpage.

  5. Sleeping distance in wild wolf packs (United States)

    Knick, S.T.; Mech, L.D.


    Sleeping distances were observed among members of 13 wild wolf (Canis lupus) packs and 11 pairs in northeastern Minnesota to determine if the distances correlated with pack size and composition. The study utilized aerial radio-tracking and observation during winter. Pack size and number of adults per pack were inversely related to pack average sleeping distance and variability. No correlation between sleeping distance and microclimate was observed. Possible relationships between social bonding and our results are discussed.

  6. The pursuit of perfect packing

    CERN Document Server

    Weaire, Denis


    In 1998 Thomas Hales dramatically announced the solution of a problem that has long teased eminent mathematicians: what is the densest possible arrangement of identical spheres? The Pursuit of Perfect Packing recounts the story of this problem and many others that have to do with packing things together. The examples are taken from mathematics, physics, biology, and engineering, including the arrangement of soap bubbles in foam, atoms in a crystal, the architecture of the bee''s honeycomb, and the structure of the Giant''s Causeway. Using an informal style and with key references, the book also includes brief accounts of the lives of many of the scientists who devoted themselves to problems of packing over many centuries, together with wry comments on their efforts. It is an entertaining introduction to the field for both specialists and the more general public.

  7. Large-scale simulation of flow and transport in reconstructed HPLC-microchip packings. (United States)

    Khirevich, Siarhei; Höltzel, Alexandra; Ehlert, Steffen; Seidel-Morgenstern, Andreas; Tallarek, Ulrich


    Flow and transport in a particle-packed microchip separation channel were investigated with quantitative numerical analysis methods, comprising the generation of confined, polydisperse sphere packings by a modified Jodrey-Tory algorithm, 3D velocity field calculations by the lattice-Boltzmann method, and modeling of convective-diffusive mass transport with a random-walk particle-tracking approach. For the simulations, the exact conduit cross section, the particle-size distribution of the packing material, and the respective average interparticle porosity (packing density) of the HPLC-microchip packings was reconstructed. Large-scale simulation of flow and transport at Peclet numbers of up to Pe = 140 in the reconstructed microchip packings (containing more than 3 x 10(5) spheres) was facilitated by the efficient use of supercomputer power. Porosity distributions and fluid flow velocity profiles for the reconstructed microchip packings are presented and analyzed. Aberrations from regular geometrical conduit shape are shown to influence packing structure and, thus, porosity and velocity distributions. Simulated axial dispersion coefficients are discussed with respect to their dependence on flow velocity and bed porosity. It is shown by comparison to experimental separation efficiencies that the simulated data genuinely reflect the general dispersion behavior of the real-life HPLC-microchip packings. Differences between experiment and simulation are explained by differing morphologies of real and simulated packings (intraparticle porosity, packing structure in the corner regions).

  8. Cylinder valve packing nut studies

    Energy Technology Data Exchange (ETDEWEB)

    Blue, S.C. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)


    The design, manufacture, and use of cylinder valve packing nuts have been studied to improve their resistance to failure from stress corrosion cracking. Stress frozen photoelastic models have been analyzed to measure the stress concentrations at observed points of failure. The load effects induced by assembly torque and thermal expansion of stem packing were observed by strain gaging nuts. The effects of finishing operations and heat treatment were studied by the strain gage hole boring and X-ray methods. Modifications of manufacturing and operation practices are reducing the frequency of stress corrosion failures.

  9. Water on hydrophobic surfaces: Mechanistic modeling of hydrophobic interaction chromatography. (United States)

    Wang, Gang; Hahn, Tobias; Hubbuch, Jürgen


    Mechanistic models are successfully used for protein purification process development as shown for ion-exchange column chromatography (IEX). Modeling and simulation of hydrophobic interaction chromatography (HIC) in the column mode has been seldom reported. As a combination of these two techniques is often encountered in biopharmaceutical purification steps, accurate modeling of protein adsorption in HIC is a core issue for applying holistic model-based process development, especially in the light of the Quality by Design (QbD) approach. In this work, a new mechanistic isotherm model for HIC is derived by consideration of an equilibrium between well-ordered water molecules and bulk-like ordered water molecules on the hydrophobic surfaces of protein and ligand. The model's capability of describing column chromatography experiments is demonstrated with glucose oxidase, bovine serum albumin (BSA), and lysozyme on Capto™ Phenyl (high sub) as model system. After model calibration from chromatograms of bind-and-elute experiments, results were validated with batch isotherms and prediction of further gradient elution chromatograms. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Assessment of pack animal welfare in and around Bareilly city of India


    Probhakar Biswas; Triveni Dutt; Patel, M.(Imperial College London, London, United Kingdom); Reena Kamal; Bharti, P.K.; Subhasish Sahu


    Aim: To assess the welfare of pack animal: Pony, Horse, Mule and Donkey in and around Bareilly city. Materials and Methods: The present study was carried out in Bareilly city and Izatnagar area of Bareilly district of Uttar Pradesh in the year 2009. Representative sample of 100 pack animal owners were selected to get the information regarding various social, personal and economic attributes of the pack animal. Further during interviewing different health and behavior pattern of animals was ke...

  11. Towards optimal packed string matching

    DEFF Research Database (Denmark)

    Ben-Kiki, Oren; Bille, Philip; Breslauer, Dany


    -size string-matching instruction wssm is available in contemporary commodity processors. The other word-size maximum-suffix instruction wslm is only required during the pattern pre-processing. Benchmarks show that our solution can be efficiently implemented, unlike some prior theoretical packed string...

  12. Heuristics for Multidimensional Packing Problems

    DEFF Research Database (Denmark)

    Egeblad, Jens

    for a three-dimensional knapsack packing problem involving furniture is presented in the fourth paper. The heuristic is based on a variety of techniques including tree-search, wall-building, and sequential placement. The solution process includes considerations regarding stability and load bearing strength...

  13. Pack cementation coatings for alloys

    Energy Technology Data Exchange (ETDEWEB)

    He, Yi-Rong; Zheng, Minhui; Rapp, R.A. [Ohio State Univ., Columbus, OH (United States)


    The halide-activated pack cementation process was modified to produce a Ge-doped silicide diffusion coating on a Cr-Cr{sub 2}Nb alloy in a single processing step. The morphology and composition of the coating depended both on the composition of the pack and on the composition and microstructure of the substrate. Higher Ge content in the pack suppressed the formation of CrSi{sub 2} and reduced the growth kinetics of the coating. Ge was not homogeneously distributed in the coatings. In cyclic and isothermal oxidation in air at 700 and 1050{degrees}C, the Ge-doped silicide coating protected the Cr-Nb alloys from significant oxidation by the formation of a Ge-doped silica film. The codeposition and diffusion of aluminum and chromium into low alloy steel have been achieved using elemental Al and Cr powders and a two-step pack cementation process. Sequential process treatments at 925{degrees}C and 1150{degrees}C yield dense and uniform ferrite coatings, whose compositions are close to either Fe{sub 3}Al or else FeAl plus a lower Cr content, when processed under different conditions. The higher content of Al in the coatings was predicted by thermodynamic calculations of equilibrium in the gas phase. The effect of the particle size of the metal powders on the surface composition of the coating has been studied for various combinations of Al and Cr powders.

  14. Characterisation of nanomaterial hydrophobicity using engineered surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Desmet, Cloé; Valsesia, Andrea; Oddo, Arianna; Ceccone, Giacomo; Spampinato, Valentina; Rossi, François; Colpo, Pascal, E-mail: [Directorate Health, Consumer and Reference Materials, Consumer Products Safety Unit (Italy)


    Characterisation of engineered nanomaterials (NMs) is of outmost importance for the assessment of the potential risks arising from their extensive use. NMs display indeed a large variety of physico-chemical properties that drastically affect their interaction with biological systems. Among them, hydrophobicity is an important property that is nevertheless only slightly covered by the current physico-chemical characterisation techniques. In this work, we developed a method for the direct characterisation of NM hydrophobicity. The determination of the nanomaterial hydrophobic character is carried out by the direct measurement of the affinity of the NMs for different collectors. Each collector is an engineered surface designed in order to present specific surface charge and hydrophobicity degrees. Being thus characterised by a combination of surface energy components, the collectors enable the NM immobilisation with surface coverage in relation to their hydrophobicity. The experimental results are explained by using the extended DLVO theory, which takes into account the hydrophobic forces acting between NMs and collectors.

  15. Synthesis and characterization of hydrophobically modified xanthan


    Roy, Audrey


    Hydrophobically modified polysaccharides show unusual rheological and interfacial properties in solution due to the self association of hydrophobic entities grafted onto their hydrophilic backbone. Their properties are tunable according to some well known parameters, such as the length of the hydrophobic moieties or the grafting density. However, very few studies deal with the influence of the backbone conformation on the properties of such systems in solution. Therefore, the objective of thi...

  16. Influence of organic cations on the crystal packing of decavanadate ...

    Indian Academy of Sciences (India)


    Influence of organic cations on the crystal packing of decavanadate containing solids. A RAMANAN, PRASUN ROY, T DURAISAMY, SANJEEV SHARMA and P AYYAPPAN. Department of Chemistry, Indian Institute of Technology, New Delhi. 110 016, India. Polyoxometallates form a rich class of inorganic materials which ...

  17. A novel reactor configuration for packed bed chemical-looping combustion of syngas

    NARCIS (Netherlands)

    Hamers, H.P.; Gallucci, F.; Cobden, P.D.; Kimball, E.; Sint Annaland, M. van


    This study reports on the application of chemical looping combustion (CLC) in pressurized packed bed reactors using syngas as a fuel. High pressure operation of CLC in packed bed has a different set of challenges in terms of material properties, cycle and reactor design compared to fluidized bed

  18. Real-time monitoring of hydrophobic aggregation reveals a critical role of cooperativity in hydrophobic effect (United States)

    Jiang, Liguo; Cao, Siqin; Cheung, Peter Pak-Hang; Zheng, Xiaoyan; Leung, Chris Wai Tung; Peng, Qian; Shuai, Zhigang; Tang, Ben Zhong; Yao, Shuhuai; Huang, Xuhui


    The hydrophobic interaction drives nonpolar solutes to aggregate in aqueous solution, and hence plays a critical role in many fundamental processes in nature. An important property intrinsic to hydrophobic interaction is its cooperative nature, which is originated from the collective motions of water hydrogen bond networks surrounding hydrophobic solutes. This property is widely believed to enhance the formation of hydrophobic core in proteins. However, cooperativity in hydrophobic interactions has not been successfully characterized by experiments. Here, we quantify cooperativity in hydrophobic interactions by real-time monitoring the aggregation of hydrophobic solute (hexaphenylsilole, HPS) in a microfluidic mixer. We show that association of a HPS molecule to its aggregate in water occurs at sub-microsecond, and the free energy change is -5.8 to -13.6 kcal mol-1. Most strikingly, we discover that cooperativity constitutes up to 40% of this free energy. Our results provide quantitative evidence for the critical role of cooperativity in hydrophobic interactions.

  19. Hydrophobic interaction membrane chromatography for bioseparation and responsive polymer ligands involved (United States)

    Chen, Jingling; Peng, Rong; Chen, Xiaonong


    Hydrophobic interaction chromatography (HIC) is a rapid growing bioseparation technique, which separates biomolecules, such as therapeutic proteins and antibodys, based on the reversible hydrophobic interaction between immobilized hydrophobic ligands on chromatographic resin spheres and non-polar regions of solute molecule. In this review, the fundamental concepts of HIC and the factors that may affect purification efficiency of HIC is summarized, followed by the comparison of HIC with affinity chromatography and ion-exchange chromatography. Hydrophobic interaction membrane chromatography (HIMC) combines the advantages of HIC and membrane process and has showed great potential in bioseparation. For better understanding of HIMC, this review presents an overview of two main concerns about HIMC, i.e. membrane materials and hydrophobic ligands. Specifically, cellulose fiber-based membrane substrate and environment-responsive ligands are emphasized.

  20. Two-Dimensional Bin Packing Problems

    NARCIS (Netherlands)

    Lodi, Andrea; Martello, Silvano; Monaci, Michele; Vigo, Daniele


    An important variant of two-dimensional bin packing problem (2BP), which is also used in some approximation algorithms for its solution, is the strip packing problem (2SP), in which the items have to be packed in a strip of width W and infinite height, so as to minimize the height at which the strip

  1. Reorganisatie van ondernemingen en pre-pack

    NARCIS (Netherlands)

    Verstijlen, Frank


    Het preadvies behandelt de opmars en wenselijkheid van de pre-pack, het verloop van de pre-pack en de positie van de onderscheidene betrokkenen bij de pre-pack, naar geldend recht en volgens (het voorontwerp voor) de Wet Continuïteit Ondernemingen I.

  2. Complications of balloon packing in epistaxis

    NARCIS (Netherlands)

    Vermeeren, Lenka; Derks, Wynia; Fokkens, Wytske; Menger, Dirk Jan|info:eu-repo/dai/nl/396566170


    Although balloon packing appears to be efficient to control epistaxis, severe local complications can occur. We describe four patients with local lesions after balloon packing. Prolonged balloon packing can cause damage to nasal mucosa, septum and alar skin (nasal mucosa, the cartilaginous skeleton

  3. Flexible starch-polyurethane films: Physiochemical characteristics and hydrophobicity. (United States)

    Tai, N L; Adhikari, Raju; Shanks, Robert; Adhikari, Benu


    Starch-polyurethane (PU) composite films with improved mechanical and hydrophobic properties were developed in this work. A simple and effective microwave-aided starch gelatinisation instrument was used to prepare glycerol plasticized high amylose starch (HAGS) material. Polyethylene glycol-isocyanate (PEG-iso) linker was prepared by reacting PEG 1000 with hexamethylene diisocyanate (HMDI). PEG-iso linker was then grafted into HAGS forming three dimensional urethane networks (PEG-PU). HAGS-PEG-PU composite blends were prepared and dried at ambient temperature to obtain HAGS-PEG-PU films. The mechanical properties and hydrophobicity (as contact angle, CA) of the HAGS-PEG-PU films were measured and analysed. Fourier transform infrared spectroscopy showed good grafting of PEG-iso into starch structure. Increase of PEG-iso concentration up to 20% (w/w) improved the molecular mixing and interpenetration between the starch and PEG-PU. The HAGS-PEG-PU films had improved hydrophobicity as indicated by CA values ranging from 51 to 110°and very high flexibility as evidenced from elongation at break (ε B ) values from 17 to 1000%. The HAGS-PEG-PU film formulation containing 20% (w/w) PEG-iso provided the best flexibility (ε B >1000%) and hydrophobicity (CA>110°). Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Hydrophobic Interactions Involved in Attachment of a Baculovirus to Hydrophobic Surfaces


    Small, Deirdre A.; Moore, Norman F.; Entwistle, Philip F.


    The hydrophobic interactions of Trichoplusia ni nuclear polyhedrosis virus were characterized by hydrophobic interaction chromatography. The determination of the hydrophobic force and some of the factors that influence its size is discussed in relation to the attachment to leaf surfaces of polyhedra during their use as biological control agents against insect pests.

  5. A Heuristic Algorithm for Solving Triangle Packing Problem

    Directory of Open Access Journals (Sweden)

    Ruimin Wang


    Full Text Available The research on the triangle packing problem has important theoretic significance, which has broad application prospects in material processing, network resource optimization, and so forth. Generally speaking, the orientation of the triangle should be limited in advance, since the triangle packing problem is NP-hard and has continuous properties. For example, the polygon is not allowed to rotate; then, the approximate solution can be obtained by optimization method. This paper studies the triangle packing problem by a new kind of method. Such concepts as angle region, corner-occupying action, corner-occupying strategy, and edge-conjoining strategy are presented in this paper. In addition, an edge-conjoining and corner-occupying algorithm is designed, which is to obtain an approximate solution. It is demonstrated that the proposed algorithm is highly efficient, and by the time complexity analysis and the analogue experiment result is found.

  6. Controlling Blown Pack Spoilage Using Anti-Microbial Packaging. (United States)

    Reid, Rachael; Bolton, Declan; Tiuftin, Andrey A; Kerry, Joe P; Fanning, Séamus; Whyte, Paul


    Active (anti-microbial) packaging was prepared using three different formulations; Auranta FV; Inbac-MDA and sodium octanoate at two concentrations (2.5 and 3.5 times their minimum inhibitory concentration (MIC, the lowest concentration that will inhibit the visible growth of the organisms) against Clostridium estertheticum, DSMZ 8809). Inoculated beef samples were packaged using the active packaging and monitored for 100 days storage at 2 °C for blown pack spoilage. The time to the onset of blown pack spoilage was significantly (p < 0.01) increased using Auranta FV and sodium octanoate (caprylic acid sodium salt) at both concentrations. Moreover, sodium octanoate packs had significantly (p < 0.01) delayed blown pack spoilage as compared to Auranta FV. It was therefore concluded that Auranta FV or sodium octanoate, incorporated into the packaging materials used for vacuum packaged beef, would inhibit blown pack spoilage and in the case of the latter, well beyond the 42 days storage period currently required for beef primals.

  7. Durability of hydrophobic treatment of concrete

    NARCIS (Netherlands)

    Vries, J. de; Polder, R.B.; Borsje, H.


    The subject of this study was the performance of hydrophobic treatment to protect concrete against chloride penetration from de-icing salts. Hydrophobic treatment makes a concrete surface absorb less water and less chloride. Several types of tests were carried out to study the performance of

  8. Durability of hydrophobic treatment of concrete

    NARCIS (Netherlands)

    Vries, J. de; Polder, R.B.; Borsje, H.


    The subject of this study was the performance of hydrophobic treatment to protect concrete against chloride penetration from de-icing salts. Hydrophobic treatment makes a concrete surface absorb less water and less chloride. Test methods and requirements for commercial products were established. In

  9. Ag/C:F Antibacterial and hydrophobic nanocomposite coatings (United States)

    Kylián, Ondřej; Kratochvíl, Jiří; Petr, Martin; Kuzminova, Anna; Slavínská, Danka; Biederman, Hynek; Beranová, Jana

    Silver-based nanomaterials that exhibit antibacterial character are intensively studied as they represent promising weapon against multi-drug resistant bacteria. Equally important class of materials represent coatings that have highly water repellent nature. Such materials may be used for fabrication of anti-fogging or self-cleaning surfaces. The aim of this study is to combine both of these valuable material characteristics. Antibacterial and highly hydrophobic Ag/C:F nanocomposite films were fabricated by means of gas aggregation source of Ag nanoparticles and sputter deposition of C:F matrix. The nanocomposite coatings had three-layer structure C:F base layer/Ag nanoparticles/C:F top layer. It is shown that the increasing number of Ag nanoparticles in produced coatings leads not only in enhancement of their antibacterial activity, but also causes substantial increase of their hydrophobicity. Under optimized conditions, the coatings are super-hydrophobic with water contact angle equal to 165∘ and are capable to induce 6-log reduction of bacteria presented in solution within 4h.

  10. Year round performance of double pass solar air heater with packed bed

    Energy Technology Data Exchange (ETDEWEB)

    El-Sebaii, A.A. [Department of Physics, Faculty of Science, Tanta University, El-Geish Street, Tanta, El-Gharbia 31527 (Egypt)]. E-mail:; Aboul-Enein, S. [Department of Physics, Faculty of Science, Tanta University, El-Geish Street, Tanta, El-Gharbia 31527 (Egypt); Ramadan, M.R.I. [Department of Physics, Faculty of Science, Tanta University, El-Geish Street, Tanta, El-Gharbia 31527 (Egypt); El-Bialy, E. [Department of Physics, Faculty of Science, Tanta University, El-Geish Street, Tanta, El-Gharbia 31527 (Egypt)


    The thermal performance of a double glass, double pass solar air heater with a packed bed (DGDPSAHPB) was investigated experimentally and theoretically. A suitable computer program was developed for the analytical solution of the energy balance equations for the various elements of the system. Numerical calculations were performed for typical summer days of 2003 using limestone and gravel as packed bed materials. To validate the proposed mathematical model, comparisons between experimental and theoretical results were performed. Good agreement was achieved. Furthermore, the effects of mass flow rate of air m radical{sub f} as well as that of the mass and porosity of the packed bed material on the outlet temperature of air T{sub flo}, thermal output power Q radical{sub u}, pressure drop {delta}P and thermohydraulic efficiency {eta}{sub TH} were also studied. Comparisons between the thermal performances of the system without and with the packed bed, either above or under the absorber plate were performed. Some experiments were also performed using iron scraps as a packed bed material. It was indicated that it is advisable to operate the system with a packed bed of low porosity above the absorber plate. The best performance was achieved with gravel as a packing material above the absorber plate when m radical{sub f} equals 0.05kg/s or lower to provide a lower pressure drop across the system and, therefore, a higher thermohydraulic efficiency {eta}{sub TH}. Values of {eta}{sub TH} with gravel were found to be 22-27% higher than that without the packed bed. The annual averages of T{sub flo} and {eta}{sub TH} were found to be 16.5% and 28.5% higher than those for the system without the packed bed; indicating an improvement of the heater performance on using a packed bed material, above or under the heater absorber, all year round.

  11. Ice pack heat sink subsystem, phase 2. [astronaut life support cooling system (United States)

    Roebelen, G. J., Jr.; Kellner, J. D.


    The report describes the design, development, fabrication, and test at one gravity of a prototype ice pack heat sink subsystem to be used eventually for astronaut cooling during manned space missions; the investigation of thermal storage material with the objective of uncovering materials with heats of fusion and/or solution in the range of 300 Btu/lb (700 kilojoules/kilogram); and the planned procedure for implementing an ice pack heat sink subsystem flight experiment. In normal use, excess heat in the liquid cooling garment (LCG) coolant is transferred to a reusable/regenerable ice pack heat sink. For emergency operation, or for extension of extravehicular activity mission time after all the ice has melted, water from the ice pack is boiled to vacuum, thereby continuing to remove heat from the LCG coolant. This subsystem incorporates a quick disconnect thermal interface between the ice pack heat sink and the subsystem heat exchanger.

  12. Nanoparticles of varying hydrophobicity at the emulsion droplet-water interface: adsorption and coalescence stability. (United States)

    Simovic, Spomenka; Prestidge, Clive A


    The coalescence stability of poly(dimethylsiloxane) emulsion droplets in the presence of silica nanoparticles ( approximately 50 nm) of varying contact angles has been investigated. Nanoparticle adsorption isotherms were determined by depletion from solution. The coalescence kinetics (determined under coagulation conditions at high salt concentration) and the physical structure of coalesced droplets were determined from optical microscopy. Fully hydrated silica nanoparticles adsorb with low affinity, reaching a maximum surface coverage that corresponds to a close packed monolayer, based on the effective particle radius and controlled by the salt concentration. Adsorbed layers of hydrophilic nanoparticles introduce a barrier to coalescence of approximately 1 kT, only slightly reduce the coalescence kinetics, and form kinetically unstable networks at high salt concentrations. Chemically hydrophobized silica nanoparticles, over a wide range of contact angles (25 to >90 degrees ), adsorb at the droplet interface with high affinity and to coverages equivalent to close-packed multilayers. Adsorption isotherms are independent of the contact angle, suggesting that hydrophobic attraction overcomes electrostatic repulsion in all cases. The highly structured and rigid adsorbed layers significantly reduce coalescence kinetics: at or above monolayer surface coverage, stable flocculated networks of droplets form and, regardless of their wettability, particles are not detached from the interface during coalescence. At sub-monolayer nanoparticle coverages, limited coalescence is observed and interfacial saturation restricts the droplet size increase. When the nanoparticle interfacial coverage is >0.7 and droplets, whereas mixtures of hydrophobized and hydrophilic nanoparticles do not effectively stabilize emulsion droplets.

  13. Solution properties of hydrophobically modified

    Directory of Open Access Journals (Sweden)

    A.M. Al-Sabagh


    Full Text Available We tested nine hydrophobically modified polyacrylamides with molecular weights situated between 1.58 and 0.89 × 106 g/mol for enhanced oil recovery applications. Their solution properties were investigated in the distilled water, brine solution, formation water and sea water. Their critical association concentrations were determined from the relationship between their concentrations and the corresponding apparent viscosities (ηapp at 30 °C at shear rate 6 s−1. They were between 0.4 and 0.5 g/dl. The brine solutions of 0.5 g/dl of HM-PAMs were investigated at different conditions regarding their apparent viscosities. Such conditions were mono and divalent cations, temperature ranging from 30 to 90 °C, the shear rate ranging from 6 to 30 s−1 and the aging time for 45 days. The surface and interfacial tensions for the HM-PAMs were measured for concentration range from 0.01 to 1 g/dl brine solutions at 30 °C and their emulsification efficiencies were investigated for 7 days. The discrepancy in the properties and efficiencies of the tested copolymers was discussed in the light of their chemical structure.

  14. Characterizing time-dependent contact angles for sands hydrophobized with oleic and stearic acids

    DEFF Research Database (Denmark)

    Subedi, S; Kawamoto, K; Jayarathna, L


    -frequency precipitation. A potential solution is to alter soil grain surfaces to become water repellent by mixing or coating the soil cover material with hydrophobic agents (HAs). In this study, hydrophobic CBs comprised of sands mixed with environmentally friendly HAs (oleic acid [OA] and stearic acid [SA]) were studied....... Water repellency (WR) characteristics for hydrophobized sand samples with different HA contents and representing different coating methods (mixing in and solvent aided) were measured. Initial contact angles (αi) for OA-coated samples sharply increased with increasing HA content and reached peak values...

  15. Characterisation of nanomaterial hydrophobicity using engineered surfaces. (United States)

    Desmet, Cloé; Valsesia, Andrea; Oddo, Arianna; Ceccone, Giacomo; Spampinato, Valentina; Rossi, François; Colpo, Pascal


    Characterisation of engineered nanomaterials (NMs) is of outmost importance for the assessment of the potential risks arising from their extensive use. NMs display indeed a large variety of physico-chemical properties that drastically affect their interaction with biological systems. Among them, hydrophobicity is an important property that is nevertheless only slightly covered by the current physico-chemical characterisation techniques. In this work, we developed a method for the direct characterisation of NM hydrophobicity. The determination of the nanomaterial hydrophobic character is carried out by the direct measurement of the affinity of the NMs for different collectors. Each collector is an engineered surface designed in order to present specific surface charge and hydrophobicity degrees. Being thus characterised by a combination of surface energy components, the collectors enable the NM immobilisation with surface coverage in relation to their hydrophobicity. The experimental results are explained by using the extended DLVO theory, which takes into account the hydrophobic forces acting between NMs and collectors. Graphical abstractDetermination of hydrophobicity character of nanomaterials by measuring their affinity to engineered surfaces.

  16. The Metallurgical Examination and Inspection of Apache Tail Rotor Strap Pack Laminates and Assemblies

    National Research Council Canada - National Science Library

    Grendahl, Scott


    The U.S. Army Research Laboratory-Weapons and Materials Research Directorate (ARL-WMRD) performed a dimensional inspection and metallurgical investigation of AH-64 Apache tail rotor strap pack assemblies and individual laminate sets...

  17. Fast Litho-Panspermia in Tightly-Packed Systems Around M Dwarfs (United States)

    Krijt, S.; Bowling, T. J.; Lyons, R. J.; Ciesla, F. J.


    We investigate the fate of impact ejecta in tightly-packed planetary architectures like the TRAPPIST-1 system, finding that material transfer in such configurations is many orders of magnitude faster compared to the inner solar system.

  18. Interaction of hydrophobic polymers with model lipid bilayers. (United States)

    Bochicchio, D; Panizon, E; Monticelli, L; Rossi, G


    The interaction of nanoscale synthetic materials with cell membranes is one of the key steps determining nanomaterials' toxicity. Here we use molecular simulations, with atomistic and coarse-grained resolution, to investigate the interaction of three hydrophobic polymers with model lipid membranes. Polymer nanoparticles made of polyethylene (PE), polypropylene (PP) and polystyrene with size up to 7 nm enter easily POPC lipid membranes, localizing to the membrane hydrophobic core. For all three materials, solid polymeric nanoparticles become essentially liquid within the membrane at room temperature. Still, their behavior in the membrane core is not the same: PP and PS disperse in the core of the bilayer, while PE shows a tendency to aggregate. We also examined the interaction of the polymers with heterogeneous membranes, consisting of a ternary lipid mixture exhibiting liquid-ordered/liquid-disordered phase separation. The behavior of the three polymers is markedly different: PP disfavors lipid phase separation, PS stabilizes it, and PE modifies the topology of the phase boundaries and causes cholesterol depletion from the liquid ordered phase. Our results show that different hydrophobic polymers have major effects on the properties of lipid membranes, calling for further investigations on model systems and cell membranes.

  19. Functional bacterial amyloid increases Pseudomonas biofilm hydrophobicity and stiffness

    DEFF Research Database (Denmark)

    Zeng, Guanghong; Vad, Brian S; Dueholm, Morten S


    hydrophobicity and mechanical properties. Using atomic force microscopy imaging and force spectroscopy, we show that the amyloid renders individual cells more resistant to drying and alters their interactions with hydrophobic probes. Importantly, amyloid makes Pseudomonas more hydrophobic and increases biofilm...

  20. Molecular Shape and the Hydrophobic Effect. (United States)

    Hillyer, Matthew B; Gibb, Bruce C


    This review focuses on papers published since 2000 on the topic of the properties of solutes in water. More specifically, it evaluates the state of the art of our understanding of the complex relationship between the shape of a hydrophobe and the hydrophobic effect. To highlight this, we present a selection of references covering both empirical and molecular dynamics studies of small (molecular-scale) solutes. These include empirical studies of small molecules, synthetic hosts, crystalline monolayers, and proteins, as well as in silico investigations of entities such as idealized hard and soft spheres, small solutes, hydrophobic plates, artificial concavity, molecular hosts, carbon nanotubes and spheres, and proteins.

  1. Hydrophobic Light-to-Heat Conversion Membranes with Self-Healing Ability for Interfacial Solar Heating. (United States)

    Zhang, Lianbin; Tang, Bo; Wu, Jinbo; Li, Renyuan; Wang, Peng


    Self-healing hydrophobic light-to-heat conversion membranes for interfacial solar heating are fabricated by deposition of light-to-heat conversion material of polypyrrole onto a porous stainless-steel mesh, followed by hydrophobic fluoroalkylsilane modification. The mesh-based membranes spontaneously stay at the water-air interface, collect and convert solar light into heat, and locally heat only the water surface for enhanced evaporation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Hydrophobic Light-to-Heat Conversion Membranes with Self-Healing Ability for Interfacial Solar Heating

    KAUST Repository

    Zhang, Lianbin


    Self-healing hydrophobic light-to-heat conversion membranes for interfacial solar heating are fabricated by deposition of light-to-heat conversion material of polypyrrole onto porous stainless steel mesh, followed by hydrophobic fluoroalkylsilane modification. The mesh-based membranes spontaneously stay at the water–air interface, collect and convert solar light into heat, and locally heat only the water surface for an enhanced evaporation.

  3. Water-Based Peeling of Thin Hydrophobic Films (United States)

    Khodaparast, Sepideh; Boulogne, François; Poulard, Christophe; Stone, Howard A.


    Inks of permanent markers and waterproof cosmetics create elastic thin films upon application on a surface. Such adhesive materials are deliberately designed to exhibit water-repellent behavior. Therefore, patterns made up of these inks become resistant to moisture and cannot be cleaned by water after drying. However, we show that sufficiently slow dipping of such elastic films, which are adhered to a substrate, into a bath of pure water allows for complete removal of the hydrophobic coatings. Upon dipping, the air-water interface in the bath forms a contact line on the substrate, which exerts a capillary-induced peeling force at the edge of the hydrophobic thin film. We highlight that this capillary peeling process is more effective at lower velocities of the air-liquid interface and lower viscosities. Capillary peeling not only removes such thin films from the substrate but also transfers them flawlessly onto the air-water interface.

  4. Frictional forces between hydrophilic and hydrophobic particle coated nanostructured surfaces

    DEFF Research Database (Denmark)

    Hansson, Petra M; Claesson, Per M.; Swerin, Agne


    not in itself provide any information on why the friction coefficient is different for different material combinations. In this study, friction forces between a colloidal probe and nanostructured particle coated surfaces in an aqueous environment exhibiting different roughness length scales were measured...... by utilizing the atomic force microscope (AFM). The chemistry of the surfaces and the probe was varied between hydrophilic silica and hydrophobized silica. For hydrophilic silica surfaces, the friction coefficient was significantly higher for the particle coated surfaces than on the flat reference surface. All...... the particle coated surfaces exhibited similar friction coefficients, from which it may be concluded that the surface geometry, and not the roughness amplitude per se, influenced the measured friction. During measurements with hydrophobic surfaces, strong adhesive forces related to the formation of a bridging...

  5. Atom interaction propensities of oxygenated chemical functions in crystal packings (United States)

    Jelsch, Christian; Bibila Mayaya Bisseyou, Yvon


    The crystal contacts of several families of hydrocarbon compounds substituted with one or several types of oxygenated chemical groups were analyzed statistically using the Hirshfeld surface methodology. The propensity of contacts to occur between two chemical types is described with the contact enrichment descriptor. The systematic large enrichment ratios of some interactions like the O—H⋯O hydrogen bonds suggests that these contacts are a driving force in the crystal packing formation. The same statement holds for the weaker C—H⋯O hydrogen bonds in ethers, esters and ketones, in the absence of polar H atoms. The over-represented contacts in crystals of oxygenated hydrocarbons are generally of two types: electrostatic attractions (hydrogen bonds) and hydrophobic interactions. While Cl⋯O interactions are generally avoided, in a minority of chloro-oxygenated hydrocarbons, significant halogen bonding does occur. General tendencies can often be derived for many contact types, but outlier compounds are instructive as they display peculiar or rare features. The methodology also allows the detection of outliers which can be structures with errors. For instance, a significant number of hydroxylated molecules displaying over-represented non-favorable oxygen–oxygen contacts turned out to have wrongly oriented hydroxyl groups. Beyond crystal packings with a single molecule in the asymmetric unit, the behavior of water in monohydrate compounds and of crystals with Z′ = 2 (dimers) are also investigated. It was found in several cases that, in the presence of several oxygenated chemical groups, cross-interactions between different chemical groups (e.g. water/alcohols; alcohols/phenols) are often favored in the crystal packings. While some trends in accordance with common chemical principles are retrieved, some unexpected results can however appear. For example, in crystals of alcohol–phenol compounds, the strong O—H⋯O hydrogen bonds between two phenol groups

  6. Atom interaction propensities of oxygenated chemical functions in crystal packings

    Directory of Open Access Journals (Sweden)

    Christian Jelsch


    Full Text Available The crystal contacts of several families of hydrocarbon compounds substituted with one or several types of oxygenated chemical groups were analyzed statistically using the Hirshfeld surface methodology. The propensity of contacts to occur between two chemical types is described with the contact enrichment descriptor. The systematic large enrichment ratios of some interactions like the O—H...O hydrogen bonds suggests that these contacts are a driving force in the crystal packing formation. The same statement holds for the weaker C—H...O hydrogen bonds in ethers, esters and ketones, in the absence of polar H atoms. The over-represented contacts in crystals of oxygenated hydrocarbons are generally of two types: electrostatic attractions (hydrogen bonds and hydrophobic interactions. While Cl...O interactions are generally avoided, in a minority of chloro-oxygenated hydrocarbons, significant halogen bonding does occur. General tendencies can often be derived for many contact types, but outlier compounds are instructive as they display peculiar or rare features. The methodology also allows the detection of outliers which can be structures with errors. For instance, a significant number of hydroxylated molecules displaying over-represented non-favorable oxygen–oxygen contacts turned out to have wrongly oriented hydroxyl groups. Beyond crystal packings with a single molecule in the asymmetric unit, the behavior of water in monohydrate compounds and of crystals with Z′ = 2 (dimers are also investigated. It was found in several cases that, in the presence of several oxygenated chemical groups, cross-interactions between different chemical groups (e.g. water/alcohols; alcohols/phenols are often favored in the crystal packings. While some trends in accordance with common chemical principles are retrieved, some unexpected results can however appear. For example, in crystals of alcohol–phenol compounds, the strong O—H...O hydrogen bonds between

  7. The “Theoreticals” Pack

    CERN Multimedia

    CERN Bulletin


    The Particle Zoo is a colourful set of hand-made soft toys representing the particles in the Standard Model and beyond. It includes a “theoreticals” pack where you can find yet undiscovered particles: the best-selling Higgs boson, the graviton, the tachyon, and dark matter. Supersymmetric particle soft toys are also available on demand. But what would happen to the zoo if Nature had prepared some unexpected surprises? Julie Peasley, the zookeeper, is ready to sew new smiling faces…   The "Theoreticals" pack in the Particle Zoo. There is only one place in the world where you can buy a smiling Higgs boson and it’s not at CERN, although this is where scientists hope to observe it. The blue star-shaped particle is the best seller of Julie Peasley’s Particle Zoo – a collection of tens of soft toys representing all sorts of particles, including composite and decaying particles.  Over the years Julie’s zoo ...

  8. Hydrophobic interactions increase attachment of gum Arabic- and PVP-coated Ag nanoparticles to hydrophobic surfaces. (United States)

    Song, Jee Eun; Phenrat, Tanapon; Marinakos, Stella; Xiao, Yao; Liu, Jie; Wiesner, Mark R; Tilton, Robert D; Lowry, Gregory V


    A fundamental understanding of attachment of surface-coated nanoparticles (NPs) is essential to predict the distribution and potential risks of NPs in the environment. Column deposition studies were used to examine the effect of surface-coating hydrophobicity on NP attachment to collector surfaces in mixtures with varying ratios of octadecylichlorosilane (OTS)-coated (hydrophobic) glass beads and clean silica (hydrophilic) glass beads. Silver nanoparticles (AgNPs) coated with organic coatings of varying hydrophobicity, including citrate, polyvinylpyrrolidone (PVP), and gum arabic (GA), were used. The attachment efficiencies of GA and PVP AgNPs increased by 2- and 4-fold, respectively, for OTS-coated glass beads compared to clean glass beads. Citrate AgNPs showed no substantial change in attachment efficiency for hydrophobic compared to hydrophilic surfaces. The attachment efficiency of PVP-, GA-, and citrate-coated AgNPs to hydrophobic collector surfaces correlated with the relative hydrophobicity of the coatings. The differences in the observed attachment efficiencies among AgNPs could not be explained by classical DLVO, suggesting that hydrophobic interactions between AgNPs and OTS-coated glass beads were responsible for the increase in attachment of surface-coated AgNPs with greater hydrophobicity. This study indicates that the overall attachment efficiency of AgNPs will be influenced by the hydrophobicity of the NP coating and the fraction of hydrophobic surfaces in the environment.

  9. Development of chromatofocusing techniques employing mixed-mode column packings for protein separations. (United States)

    Guo, Hui; Li, Xiang; Frey, Douglas D


    Recent studies reported in the literature using mixed-mode chromatography (MMC) column packings have shown that multiple modes of interactions between the column packing and proteins can be usefully exploited to yield excellent resolution as well as salt-tolerant adsorption of the target protein. In this study, a mixed-mode separation method using commercially available column packings was explored which combines the techniques of hydrophobic-interaction chromatography and chromatofocusing. Two different column packings, one based on mercapto-ethyl-pyridine (MEP) and the other based on hexylamine (HEA) were investigated with regard to their ability to separate proteins when using internally generated, retained pH gradients. The effects of added salt and urea on the behavior of the retained pH gradient and the protein separation achieved when using MMC column packings for chromatofocusing were also investigated. Numerical simulations using methods developed in previous work were shown to agree with experimental results when using reasonable physical parameters. These numerical simulations were also shown to be a useful qualitative method to select the compositions of the starting and elution buffers in order to achieve desired shapes for the pH and ionic strength gradients. The use of the method to fractionate blood serum was explored as a prototype example application. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Laboratory Investigation of the Hydrophobicity Transfer Mechanism on Composite Insulators Aged in Coastal Service

    Directory of Open Access Journals (Sweden)

    N. Mavrikakis


    Full Text Available Silicone rubber (SIR insulators are known to maintain their surface hydrophobicity even under severe pollution conditions in contrast to the other composite insulator materials used at the last decades. This critical advantage of silicone rubber insulators has made them dominant in high voltage power systems despite the fact that there are other composite materials with better static hydrophobicity. In service conditions, priority is given to the dynamic performance of hydrophobicity due to the unpredictable environmental pollution conditions. This dynamic performance of silicone rubber insulators is also known as hydrophobicity transfer mechanism. In literature, the hydrophobicity transfer mechanism of silicone rubber is related to the reorientation of methyl-groups and the existence of low molecular weight components. However there are many parameters which can change the effectiveness of this mechanism. Some of them referred to the ageing effects on the material structure. Thus it is of great importance to investigate the hydrophobicity transfer mechanism of field aged composite insulators. For this reason a new experimental procedure is introduced based on Cigre TB 442. The results of field aged insulators are compared to that of a new SIR insulator revealing the superiority of silicone rubber even after 17 years of field ageing.

  11. The new method of modifying the hydrophobic properties of expanded perlite

    Directory of Open Access Journals (Sweden)

    Vogt Elżbieta


    Full Text Available The progressive industrialization and development of the automotive industry is the cause of the increasing demand for chemical products, especially oil products. Unfortunately, during processing, transportation or storage of these products, they get very often into the environment causing pollution. The removal of the results of accidents is still a current problem. The techniques which employ various types of sorbents deserve special attention among the several methods of eliminating the effects of pollutions. Moreover, expanded hydrophobic perlite is an interesting material among sorbents which are used on a large scale. The new method of modifying the hydrophobic properties of expanded perlite, with the use of solutions of stearic acid in organic solvents, was presented. The perlite that was used in research was produced by the PerliPol registered partnership in Bełchatów. Hydrophobic properties of the obtained materials were determined on the basis of the results achieved due to the modified film flotation method, “floating on water” test and on the basis of the value of water retention for individual samples. All grain fractions of perlite obtained hydrophobic properties which were better than or comparable to the hydrophobic properties of the HydroPerl (PerlPol commercial material used to remove petroleum product pollution. The hydrophobization process significantly improved the adsorption capacity of modified perlite to petroleum product pollution.

  12. Hydrophobicity of carbohydrates and related hydroxy compounds. (United States)

    Buttersack, Christoph


    The hydrophobic interaction of carbohydrates and other hydroxy compounds with a C18-modified silica gel column was measured with pure water as eluent, thereby expanding the range of measurements already published. The interaction is augmented by structure strengthening salts and decreasing temperature. Although the interaction of the solute with the hydrophobic interface is expected to only imperfectly reflect its state in aqueous bulk solution, the retention can be correlated to hydration numbers calculated from molecular mechanics studies given in the literature. No correlation can be established towards published hydration numbers obtained by physical methods (isentropic compressibility, O-17 NMR relaxation, terahertz spectroscopy, and viscosity). The hydrophobicity is discussed with respect to the chemical structure. It increases with the fraction and size of hydrophobic molecular surface regions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Continuous Droplet Removal upon Dropwise Condensation of Humid Air on a Hydrophobic Micropatterned Surface (United States)


    Combination of two physical phenomena, capillary pressure gradient and wettability gradient, allows a simple two-step fabrication process that yields a reliable hydrophobic self-cleaning condenser surface. The surface is fabricated with specific microscopic topography and further treatment with a chemically inert low-surface-energy material. This process does not require growth of nanofeatures (nanotubes) or hydrophilic–hydrophobic patterning of the surface. Trapezoidal geometry of the microfeatures facilitates droplet transfer from the Wenzel to the Cassie state and reduces droplet critical diameter. The geometry of the micropatterns enhances local coalescence and directional movement for droplets with diameter much smaller than the radial length of the micropatterns. The hydrophobic self-cleaning micropatterned condenser surface prevents liquid film formation and promotes continuous dropwise condensation cycle. Upon dropwise condensation, droplets follow a designed wettability gradient created with micropatterns from the most hydrophobic to the least hydrophobic end of the surface. The surface has higher condensation efficiency, due to its directional self-cleaning property, than a plain hydrophobic surface. We explain the self-actuated droplet collection mechanism on the condenser surface and demonstrate experimentally the creation of an effective wettability gradient over a 6 mm radial distance. In spite of its fabrication simplicity, the fabricated surface demonstrates self-cleaning property, enhanced condensation performance, and reliability over time. Our work enables creation of a hydrophobic condenser surface with the directional self-cleaning property that can be used for collection of biological (chemical, environmental) aerosol samples or for condensation enhancement. PMID:25073014

  14. High throughput laser texturing of super-hydrophobic surfaces on steel (United States)

    Gemini, Laura; Faucon, Marc; Romoli, Luca; Kling, Rainer


    Super-hydrophobic surfaces are nowadays of primary interest in several application fields, as for de-icing devices in the automotive and aerospace industries. In this context, laser surface texturing has widely demonstrated to be an easy one-step method to produce super-hydrophobic surfaces on several materials. In this work, a high average power (up to 40W), high repetition-rate (up to 1MHz), femtosecond infrared laser was employed to produce super-hydrophobic surfaces on 316L steel. The set of process and laser parameters for which the super-hydrophobic behavior is optimized, was obtained by varying the laser energy and repetition rate. The morphology of the textured surfaces was firstly analyzed by SEM and confocal microscope analyses. The contact angle was measured over time in order to investigate the effect of air environment on the hydrophobic properties and define the period of time necessary for the super-hydrophobic properties to stabilize. An investigation on the effect of after-processing cleaning solvents on the CA evolution was carried to assess the influence of the after-processing sample handling on the CA evaluation. Results show that the highest values of contact angle, that is the best hydrophobic behavior, are obtained at high repetition rate and low energy, this way opening up a promising scenario in terms of upscaling for reducing the overall process takt-time.

  15. Pebble bed packing in prismatic containers

    Energy Technology Data Exchange (ETDEWEB)

    Reimann, Joerg, E-mail: [Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe (Germany); Abou-Sena, Ali [Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe (Germany); Nippen, Rainer [KBHF GmbH, Herrmann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Tafforeau, Paul [European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble Cedex (France)


    Highlights: • The essential part of ceramic breeder blankets is pebble beds. • The packing factor for blanket relevant cavities must be known. • Tomography experiments revealed details of packing arrangements. • Packing experiments confirm that reference packing factors will be achieved. -- Abstract: New analyses of previous tomography investigations show in detail void fraction fluctuations close to walls generated by regular pebble arrangements. Local packing factors within the pebble bed were determined for characteristic zones. These results are very helpful for the interpretation of the packing experiments performed with spherical pebbles in different kinds of Plexiglas containers dominated by flat walls. The packing factors for single-size pebbles in the containers with a piston on top are fairly independent of bed height unless the height to diameter ratio becomes less than 10. For the closed rectangular containers, the development of structured packings is rendered more difficult. However, for blanket relevant bed heights, both for orthosilicate and beryllium pebbles, the packing factors obtained which agree well with previously obtained reference values.

  16. Singlet Fission in Rubrene Derivatives: Impact of Molecular Packing

    KAUST Repository

    Sutton, Christopher


    We examine the properties of six recently synthesized rubrene derivatives (with substitutions on the side phenyl rings) that show vastly different crystal structures. In order to understand how packing in the solid state affects the excited states and couplings relevant for singlet fission, the lowest excited singlet (S), triplet (T), multiexciton (TT), and charge-transfer (CT) states of the rubrene derivatives are compared to known singlet fission materials [tetracene, pentacene, 5,12-diphenyltetracene (DPT), and rubrene itself]. While a small difference of less than 0.2 eV is calculated for the S and TT energies, a range of 0.50 to 1.2 eV in the CT energies and nearly 3 orders of magnitude in the electronic couplings are computed for the rubrene derivatives in their crystalline packings, which strongly affects the role of the CT state in facilitating SF. To rationalize experimental observations of singlet fission occurring in amorphous phases of rubrene, DPT, and tetracene, we use molecular dynamics (MD) simulations to assess the impact of molecular packing and orientations and to gain a better understanding of the parameters that control singlet fission in amorphous films compared to crystalline packings. The MD simulations point to a crystalline-like packing for thin films of tetracene; on the other hand, DPT, rubrene, and the rubrene derivatives all show various degrees of disorder with a number of sites that have larger electronic couplings than in the crystal, which can facilitate singlet fission in such thin films. Our analysis underlines the potential of these materials as promising candidates for singlet fission and helps understand how various structural motifs affect the critical parameters that control the ability of a system to undergo singlet fission.

  17. Characterization of surface hydrophobicity of engineered nanoparticles. (United States)

    Xiao, Yao; Wiesner, Mark R


    The surface chemistry of nanoparticles, including their hydrophobicity, is a key determinant of their fate, transport and toxicity. Engineered NPs often have surface coatings that control the surface chemistry of NPs and may dominate the effects of the nanoparticle core. Suitable characterization methods for surface hydrophobicity at the nano-scale are needed. Three types of methods, surface adsorption, affinity coefficient and contact angle, were investigated in this study with seven carbon and metal based NPs with and without coatings. The adsorption of hydrophobic molecules, Rose Bengal dye and naphthalene, on NPs was used as one measure of hydrophobicity and was compared with the relative affinity of NPs for octanol or water phases, analogous to the determination of octanol-water partition coefficients for organic molecules. The sessile drop method was adapted for measuring contact angle of a thin film of NPs. Results for these three methods were qualitatively in agreement. Aqueous-nC(60) and tetrahydrofuran-nC(60) were observed to be more hydrophobic than nano-Ag coated with polyvinylpyrrolidone or gum arabic, followed by nano-Ag or nano-Au with citrate-functionalized surfaces. Fullerol was shown to be the least hydrophobic of seven NPs tested. The advantages and limitations of each method were also discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Enhanced Permeation of a Hydrophobic Fluid through Particles with Hydrophobic and Hydrophilic Patterned Surfaces


    Renliang Zhang; Yousheng Xu; Binghai Wen; Nan Sheng; Haiping Fang


    The wetting properties of solid surfaces are significant in oil/gas and liquid displacement processes. It is difficult for hydrophobic fluids to permeate channels filled with hydrophilic particles and an aqueous phase, and this is thought to be the primary cause of low yields in low permeability reservoir operations. Using three-dimensional lattice Boltzmann simulations, we show that particles with hydrophobic and hydrophilic patterned surfaces can greatly improve hydrophobic fluid permeation...

  19. Packing of Helices: Is Chirality the Highest Crystallographic Symmetry?

    Directory of Open Access Journals (Sweden)

    Romain Gautier


    Full Text Available Chiral structures resulting from the packing of helices are common in biological and synthetic materials. Herein, we analyze the noncentrosymmetry (NCS in such systems using crystallographic considerations. A comparison of the chiral structures built from helices shows that the chirality can be expected for specific building units such as 31/32 or 61/65 helices which, in hexagonal arrangement, will more likely lead to a chiral resolution. In these two systems, we show that the highest crystallographic symmetry (i.e., the symmetry which can describe the crystal structure from the smallest assymetric unit is chiral. As an illustration, we present the synthesis of two materials ([Zn(2,2’-bpy3](NbF62 and [Zn(2,2’-bpy3](TaF62 in which the 3n helices pack into a chiral structure.

  20. Destabilization of confined granular packings due to fluid flow (United States)

    Monloubou, Martin; Sandnes, Bjørnar


    Fluid flow through granular materials can cause fluidization when fluid drag exceeds the frictional stress within the packing. Fluid driven failure of granular packings is observed in both natural and engineered settings, e.g. soil liquefaction and flowback of proppants during hydraulic fracturing operations. We study experimentally the destabilization and flow of an unconsolidated granular packing subjected to a point source fluid withdrawal using a model system consisting of a vertical Hele-Shaw cell containing a water-grain mixture. The fluid is withdrawn from the cell at a constant rate, and the emerging flow patterns are imaged in time-lapse mode. Using Particle Image Velocimetry (PIV), we show that the granular flow gets localized in a narrow channel down the center of the cell, and adopts a Gaussian velocity profile similar to those observed in dry grain flows in silos. We investigate the effects of the experimental parameters (flow rate, grain size, grain shape, fluid viscosity) on the packing destabilization, and identify the physical mechanisms responsible for the observed complex flow behaviour.

  1. Hydrophobic thickness of fluid planar monooleylglycerol membran maximally thinned by inversed micellisation

    DEFF Research Database (Denmark)

    Knudsen, P. J.; Mouritsen, Ole G.


    A procedure of making membranes of amphiphilic materials at the bottom of a U-shaped flexible plastic tube within an aqueous medium is described. The membranes were made sufficiently large in order for the annulus area to be neglected. Consequently the hydrophobic thickness of the membrane could...... be measured by a capacitance technique assuming the relative permittivity of the hydrophobic part of the bilayer. Introduction of an AC microvolt technique allowed manufacture of stable thick membranes by quenching the electroconstriction observed when DC electrical potentials in the millivolt range are used....... By continuously monitoring the hydrophobic thickness and by use of the AC microvolt technique the membrane-thinning process by chemical means could be studied in isolation because the electroconstriction was quenched. The maximally thinned hydrophobic thickness of a monooleylglycerol membrane measured at 38...

  2. Chemical treatment of the intra-canal dentin surface: a new approach to modify dentin hydrophobicity

    Directory of Open Access Journals (Sweden)



    Full Text Available Objective This study evaluated the hydrophobicity of dentin surfaces that were modified through chemical silanization with octadecyltrichlorosilane (OTS. Material and Methods An in vitro experimental study was performed using 40 human permanent incisors that were divided into the following two groups: non-silanized and silanized. The specimens were pretreated and chemically modified with OTS. After the chemical modification, the dentin hydrophobicity was examined using a water contact angle measurement (WCA. The effectiveness of the modification of hydrophobicity was verified by the fluid permeability test (FPT. Results and Conclusions Statistically significant differences were found in the values of WCA and FPT between the two groups. After silanization, the hydrophobic intraradicular dentin surface exhibited in vitro properties that limit fluid penetration into the sealed root canal. This chemical treatment is a new approach for improving the sealing of the root canal system.

  3. Does Post Septoplasty Nasal Packing Reduce Complications?

    Directory of Open Access Journals (Sweden)

    Bijan Naghibzadeh


    Full Text Available The main issues in nasal surgery are to stabilize the nose in the good position after surgery and preserve the cartilages and bones in the favorable situation and reduce the risk of deviation recurrence. Also it is necessary to avoid the synechia formation, nasal valve narrowing, hematoma and bleeding. Due to the above mentioned problems and in order to solve and minimize them nasal packing, nasal splint and nasal mold have been advised. Patients for whom the nasal packing used may faced to some problems like naso-pulmonary reflex, intractable pain, sleep disorder, post operation infection and very dangerous complication like toxic shock syndrome. We have two groups of patients and three surgeons (one of the surgeons used post operative nasal packing in his patients and the two others surgeons did not.Complications and morbidities were compared in these two groups. Comparing the two groups showed that the rate of complication and morbidities between these two groups were same and the differences were not valuable, except the pain and discomfort post operatively and at the time of its removal. Nasal packing has several risks for the patients while its effects are not studied. Septoplasty can be safely performed without postoperative nasal packing. Nasal packing had no main findings that compensated its usage. Septal suture is one of the procedures that can be used as alternative method to nasal packing. Therefore the nasal packing after septoplasty should be reserved for the patients with increased risk of bleeding.

  4. 21 CFR 890.5700 - Cold pack. (United States)


    ... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5700 Cold pack. (a) Identification. A cold pack is a device intended for medical purposes that consists of a compact fabric envelope...

  5. Hardness of approximation for strip packing

    DEFF Research Database (Denmark)

    Adamaszek, Anna Maria; Kociumaka, Tomasz; Pilipczuk, Marcin


    -dimensional knapsack. In this article, we answer this question in negative by proving that it is NP-hard to approximate strip packing within a factor better than 12/11, even when restricted to polynomially bounded input data. In particular, this shows that the strip packing problem admits no quasi-polynomial time...

  6. Protein packing quality using Delaunay complexes

    DEFF Research Database (Denmark)

    Fonseca, Rasmus; Winter, Pawel; Karplus, Kevin


    A new method for estimating the packing quality of protein structures is presented. Atoms in high quality protein crystal structures are very uniformly distributed which is difficult to reproduce using structure prediction methods. Packing quality measures can therefore be used to assess structur...

  7. Water interaction with hydrophobic and hydrophilic soot particles. (United States)

    Popovicheva, Olga; Persiantseva, Natalia M; Shonija, Natalia K; DeMott, Paul; Koehler, Kirsten; Petters, Markus; Kreidenweis, Sonia; Tishkova, Victoria; Demirdjian, Benjamin; Suzanne, Jean


    The interaction of water with laboratory soots possessing a range of properties relevant for atmospheric studies is examined by two complementary methods: gravimetrical measurement of water uptake coupled with chemical composition and porosity analysis and HTDMA (humidified tandem differential mobility analyzer) inference of water uptake accompanied by separate TEM (transmission electron microscopy) analysis of single particles. The first method clarifies the mechanism of water uptake for bulk soot and allows the classification of soot with respect to its hygroscopicity. The second method highlights the dependence of the soot aerosol growth factor on relative humidity (RH) for quasi-monodisperse particles. Hydrophobic and hydrophilic soot are qualitatively defined by their water uptake and surface polarity: laboratory soot particles are thus classified from very hydrophobic to very hydrophilic. Thermal soot particles produced from natural gas combustion are classified as hydrophobic with a surface of low polarity since water is found to cover only half of the surface. Graphitized thermal soot particles are proposed for comparison as extremely hydrophobic and of very low surface polarity. Soot particles produced from laboratory flame of TC1 aviation kerosene are less hydrophobic, with their entire surface being available for statistical monolayer water coverage at RH approximately 10%. Porosity measurements suggest that, initially, much of this surface water resides within micropores. Consequently, the growth factor increase of these particles to 1.07 at RH > 80% is attributed to irreversible swelling that accompanies water uptake. Hysteresis of adsorption/desorption cycles strongly supports this conclusion. In contrast, aircraft engine soot, produced from burning TC1 kerosene in a gas turbine engine combustor, has an extremely hydrophilic surface of high polarity. Due to the presence of water soluble organic and inorganic material it can be covered by many water


    Cationic surfactants can be used to modify surfaces of soils and subsurface materials to promote adsorption of hydrophobic organic compounds (HOC). Batch and column experiments were performed to investigate this phenomenon with the cationic surfactant dodecylpyridinium (DP), a se...

  9. What makes zeolitic imidazolate frameworks hydrophobic or hydrophilic? The impact of geometry and functionalization on water adsorption. (United States)

    Ortiz, Aurélie U; Freitas, Alexy P; Boutin, Anne; Fuchs, Alain H; Coudert, François-Xavier


    We demonstrate, by means of Grand Canonical Monte Carlo simulation on different members of the ZIF family, how topology, geometry, and linker functionalization drastically affect the water adsorption properties of these materials, tweaking the ZIF materials from hydrophobic to hydrophilic. We show that adequate functionalization of the linkers allows one to tune the host-guest interactions, even featuring dual amphiphilic materials whose pore space features both hydrophobic and hydrophilic regions. Starting from an initially hydrophobic material (ZIF-8), various degrees of hydrophilicity could be obtained, with a gradual evolution from a type V adsorption isotherm in the liquid phase to a type I isotherm in the gas phase. This behavior is similar to what was described earlier in families of hydrophobic all-silica zeolites, with hydrophilic "defects" of various strength, such as silanol nests or the presence of extra-framework cations.

  10. Merocel versus Nasopore for nasal packing: a meta-analysis of randomized controlled trials.

    Directory of Open Access Journals (Sweden)

    Jianzhang Wang

    Full Text Available OBJECTIVE: To compare the clinical outcomes, including efficacy and complications, of Merocel versus Nasopore as a nasal packing material after nasal surgery. METHODS: Relevant randomized controlled trials were identified from electronic databases (The Cochrane Library, PubMed, EMBASE, China National Knowledge Infrastructure and Chinese Biomedical Database. Conference proceedings and references from identified trials and review articles were also searched. Outcome measures were pain during nasal packing, pain and bleeding upon packing removal, pressure sensation, nasal blockage, formation of synechiae, mucosal healing, and patients' general satisfaction. RESULTS: Seven randomized controlled trials met criteria for analysis. Compared with Merocel, Nasopore significantly reduced patients' subjective symptoms including in situ pain (pain experienced while packing is in place, nasal pressure, pain and bleeding during packing removal, and increased patients' general satisfaction with nasal packing. There were no significant differences in nasal obstruction, adhesion and mucosal healing between the Merocel and Nasopore groups. CONCLUSIONS: Preliminary evidence suggests that Nasopore may be superior to Merocel as a nasal packing material with regard to in situ pain, pain and bleeding upon removal, pressure, and general satisfaction and does not differ from Merocel in terms of nasal obstruction, tissue adhesion, and long-term mucosal healing.

  11. Sterility of Gauze Packed in One and Three Layer Layer Parchment Paper

    Directory of Open Access Journals (Sweden)

    Saskia Biyakto Putri


    Full Text Available Intoduction: Sterile gauze is one of the medical devices that are often used to prevent infection. Several things, one of them is materials for packaging, can affect the sterility of gauze. Parchment paper is one of the packaging materials for sterilization. The study was done to analyze the sterility of gauze packed with parchment paper one layer and three layers on the growth of microorganism. Method: This study was an experimental study with a quasi-experimental design. Samples were 60 gauze packed with one layer parchment paper and 60 gauze packed with three layers of parchment paper. The sterility of sterile gauze tested at weeks 0, 2 and 4. Results: There was no significant difference in the sterility of gauze packed with 1 layer of parchment paper on the growth of microorganisms at 0, 2, 4 weeks (p = 0.126. No significant difference in the sterility of sterile gauze packed with 3 layers of parchment paper at 0, 2, 4 weeks (p = 0.675. There was a significant difference in the sterility of sterile gauze packed with parchment paper 1 layer and 3 layers on the growth of microorganisms (p = 0.002. Conclusion There is a significant difference of sterile gauze packed with parchment paper 1 layer and 3 layers against the growth of microorganisms. The sterility of the packaged sterile gauze with a layer of parchment paper is better than the three layers.

  12. Hawking Colloquium Packed CERN Auditoriums

    CERN Multimedia


    Stephen Hawking's week long visit to CERN included an 'exceptional CERN colloquium' which filled six auditoriums. Stephen Hawking during his visit to the ATLAS experiment. Stephen Hawking, Lucasian Professor of Cambridge University, visited the Theory Unit of the Physics Department from 24 September to 1 October 2006. As part of his visit, he gave two lectures in the main auditorium - a theoretical seminar on 'The Semi-Classical Birth of The Universe', attended by about 120 specialists; and a colloquium titled 'The Origin of The Universe'. As a key public figure in theoretical physics, his presence was eagerly awaited on both occasions. Those who wanted to attend the colloquium had to arrive early and be equipped with plenty of patience. An hour before it was due to begin, the 400 capacity of the main auditorium was already full. The lecture, simultaneously broadcast to five other fully packed CERN auditoriums, was attended by an estimated total of 850. Stephen Hawking attracted a large CERN crowd, filling ...

  13. Characterization of hydrophobic nanoporous particle liquids for energy absorption (United States)

    Hsu, Yi; Liu, Yingtao


    Recently, the development of hydrophobic nanoporous technologies has drawn increased attention, especially for the applications of energy absorption and impact protection. Although significant amount of research has been conducted to synthesis and characterize materials to protect structures from impact damage, the tradition methods focused on converting kinetic energy to other forms, such as heat and cell buckling. Due to their high energy absorption efficiency, hydrophobic nanoporous particle liquids (NPLs) are one of the most attractive impact mitigation materials. During impact, such particles directly trap liquid molecules inside the non-wetting surface of nanopores in the particles. The captured impact energy is simply stored temporarily and isolated from the original energy transmission path. In this paper we will investigate the energy absorption efficiency of combinations of silica nanoporous particles and with multiple liquids. Inorganic particles, such as nanoporous silica, are characterized using scanning electron microscopy. Small molecule promoters, such as methanol and ethanol, are introduced to the prepared NPLs. Their effects on the energy absorption efficiency are studied in this paper. NPLs are prepared by dispersing the studied materials in deionized water. Energy absorption efficiency of these liquids are experimentally characterized using an Instron mechanical testing frame and in-house develop stainless steel hydraulic cylinder system.

  14. Biosurfactant-enhanced bioremediation of hydrophobic pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Cameotra, S.S.; Makkar, R.S. [Inst. of Microbial Technology, Chandigarh (India)


    Biosurfactants are surface-active compounds synthesized by a wide variety of microorganisms. They are molecules that have both hydrophobic and - philic domains and are capable of lowering the surface tension and the interfacial tension of the growth medium. Biosurfactants possess different chemical structures-lipopeptides, glycolipids, neutral lipids, and fatty acids. They are nontoxic biomolecules that are biodegradable. Biosurfactants also exhibit strong emulsification of hydrophobic compounds and form stable emulsions. Polycyclic aromatic hydrocarbons (PAHs), crude on sludge, and pesticides call be toxic, mutagenic, and carcinogenic compounds that pollute the environment. They are released into the environment as a result of oil spillage and by-products of coal treatment processes. The low water solubility of these compounds limits their availability to microorganisms, which is a potential problem for bioremediation of contaminated sites. Microbially produced surfactants enhance the bioavailability of these hydrophobic compounds for bioremediation. Therefore, biosurfactant-enhanced solubility of pollutants has potential hioremediation applications.

  15. Materialism. (United States)

    Melnyk, Andrew


    Materialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature is intentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature is phenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state. WIREs Cogn Sci 2012, 3:281-292. doi: 10.1002/wcs.1174 For further resources related to this article, please visit the WIREs website. Copyright © 2012 John Wiley & Sons, Ltd.

  16. Binding of hydrophobic antigens to surfaces

    DEFF Research Database (Denmark)


    A first aspect of the present invention is a method of detecting antibodies comprising the steps of: i) providing a first group of beads comprising a surface modified with C1-C10 alkyl groups comprising amine, ammonium, ether and/or hydroxyl groups, ii) contacting said first group of beads...... with a first hydrophobic antigen to provide a first group of bead-antigen conjugates by adsorption of the first hydrophobic antigen on the first group of beads, iii) isolating said bead- antigen conjugates, iv) contacting said bead-antigen conjugates with a sample to bind antibodies therein to provide bead...

  17. Switchable Hydrophobic-Hydrophilic Surfaces

    CERN Document Server

    Bunker, B C; Huber, D L; Kent, M S; Kushmerick, J G; Lopez, G P; Manginell, R P; Méndez, S E; Yim, H


    Tethered films of poly n-isopropylacrylamide (PNIPAM) films have been developed as materials that can be used to switch the chemistry of a surface in response to thermal activation. In water, PNIPAM exhibits a thermally-activated phase transition that is accompanied by significant changes in polymer volume, water contact angle, and protein adsorption characteristics. New synthesis routes have been developed to prepare PNIPAM films via in-situ polymerization on self-assembled monolayers. Swelling transitions in tethered films have been characterized using a wide range of techniques including surface plasmon resonance, attenuated total reflectance infrared spectroscopy, interfacial force microscopy, neutron reflectivity, and theoretical modeling. PNIPAM films have been deployed in integrated microfluidic systems. Switchable PNIPAM films have been investigated for a range of fluidic applications including fluid pumping via surface energy switching and switchable protein traps for pre-concentrating and separating...

  18. Modular vaccine packaging increases packing efficiency. (United States)

    Norman, Bryan A; Rajgopal, Jayant; Lim, Jung; Gorham, Katrin; Haidari, Leila; Brown, Shawn T; Lee, Bruce Y


    Within a typical vaccine supply chain, vaccines are packaged into individual cylindrical vials (each containing one or more doses) that are bundled together in rectangular "inner packs" for transport via even larger groupings such as cold boxes and vaccine carriers. The variability of vaccine inner pack and vial size may hinder efficient vaccine distribution because it constrains packing of cold boxes and vaccine carriers to quantities that are often inappropriate or suboptimal in the context of country-specific vaccination guidelines. We developed in Microsoft Excel (Microsoft Corp., Redmond, WA) a spreadsheet model that evaluated the impact of different packing schemes for the Benin routine regimen plus the introduction of the Rotarix vaccine. Specifically, we used the model to compare the current packing scheme to that of a proposed modular packing scheme. Conventional packing of a Dometic RCW25 that aims to maximize fully-immunized children (FICs) results in 123 FICs and a packing efficiency of 81.93% compared to a maximum of 155 FICs and 94.1% efficiency for an alternative modular packaging system. Our analysis suggests that modular packaging systems could offer significant advantages over conventional vaccine packaging systems with respect to space efficiency and potential FICs, when they are stored in standard vaccine carrying devices. This allows for more vaccines to be stored within the same volume while also simplifying the procedures used by field workers to pack storage devices. Ultimately, modular packaging systems could be a simple way to help increase vaccine coverage worldwide. Copyright © 2015. Published by Elsevier Ltd.

  19. Intelligent 3D packing using a grouping algorithm for automotive container engineering

    Directory of Open Access Journals (Sweden)

    Youn-Kyoung Joung


    Full Text Available Storing, and the loading and unloading of materials at production sites in the manufacturing sector for mass production is a critical problem that affects various aspects: the layout of the factory, line-side space, logistics, workers’ work paths and ease of work, automatic procurement of components, and transfer and supply. Traditionally, the nesting problem has been an issue to improve the efficiency of raw materials; further, research into mainly 2D optimization has progressed. Also, recently, research into the expanded usage of 3D models to implement packing optimization has been actively carried out. Nevertheless, packing algorithms using 3D models are not widely used in practice, due to the large decrease in efficiency, owing to the complexity and excessive computational time. In this paper, the problem of efficiently loading and unloading freeform 3D objects into a given container has been solved, by considering the 3D form, ease of loading and unloading, and packing density. For this reason, a Group Packing Approach for workers has been developed, by using analyzed truck packing work patterns and Group Technology, which is to enhance the efficiency of storage in the manufacturing sector. Also, an algorithm for 3D packing has been developed, and implemented in a commercial 3D CAD modeling system. The 3D packing method consists of a grouping algorithm, a sequencing algorithm, an orientating algorithm, and a loading algorithm. These algorithms concern the respective aspects: the packing order, orientation decisions of parts, collision checking among parts and processing, position decisions of parts, efficiency verification, and loading and unloading simulation. Storage optimization and examination of the ease of loading and unloading are possible, and various kinds of engineering analysis, such as work performance analysis, are facilitated through the intelligent 3D packing method developed in this paper, by using the results of the 3D

  20. Consequences of water between two hydrophobic surfaces on adhesion and wetting. (United States)

    Defante, Adrian P; Burai, Tarak N; Becker, Matthew L; Dhinojwala, Ali


    The contact of two hydrophobic surfaces in water is of importance in biology, catalysis, material science, and geology. A tenet of hydrophobic attraction is the release of an ordered water layer, leading to a dry contact between two hydrophobic surfaces. Although the water-free contact has been inferred from numerous experimental and theoretical studies, this has not been directly measured. Here, we use surface sensitive sum frequency generation spectroscopy to directly probe the contact interface between hydrophobic poly(dimethylsiloxane) (PDMS) and two hydrophobic surfaces (a self-assembled monolayer, OTS, and a polymer coating, PVNODC). We show that the interfacial structures for OTS and PVNODC are identical in dry contact but that they differ dramatically in wet contact. In water, the PVNODC surface partially rearranges at grain boundaries, trapping water at the contact interface leading to a 50% reduction in adhesion energy compared to OTS-PDMS contact. The Young-Dupré equation, used extensively to calculate the thermodynamic work of adhesion, predicts no differences between the adhesion energy for these two hydrophobic surfaces, indicating a failure of this well-known equation when there is a heterogeneous contact. This study exemplifies the importance of interstitial water in controlling adhesion and wetting.

  1. Hydrophobic Modification of Layered Clays and Compatibility for Epoxy Nanocomposites (United States)

    Lin, Jiang-Jen; Chan, Ying-Nan; Lan, Yi-Fen


    Recent studies on the intercalation and exfoliation of layered clays with polymeric intercalating agents involving poly(oxypropylene)-amines and the particular uses for epoxy nanocomposites are reviewed. For intercalation, counter-ionic exchange reactions of clays including cationic layered silicates and anionic Al-Mg layered double hydroxide (LDH) with polymeric organic ions afforded organoclays led to spatial interlayer expansion from 12 to 92 Å (X-ray diffraction) as well as hydrophobic property. The inorganic clays of layered structure could be modified by the poly(oxypropylene)amine-salts as the intercalating agents with molecular weights ranging from 230 to 5,000 g/mol. Furthermore, natural montmorillonite (MMT) clay could be exfoliated into thin layer silicate platelets (ca. 1 nm thickness) in one step by using polymeric types of exfoliating agents. Different lateral dimensions of MMT, synthetic fluorinated Mica and LDH clays had been cured into epoxy nanocomposites. The hydrophobic amine-salt modification resulting in high spacing of layered or exfoliation of individual clay platelets is the most important factor for gaining significant improvements of properties. In particular, these modified clays were reported to gain significant improvements such as reduced coefficient of thermal expansion (CTE), enhanced thermal stability, and hardness. The utilization of these layered clays for initiating the epoxy self-polymerization was also reported to have a unique compatibility between clay and organic resin matrix. However, the matrix domain lacks of covalently bonded crosslink and leads to the isolation of powder material. It is generally concluded that the hydrophobic expansion of the clay inter-gallery spacing is the crucial step for enhancing the compatibility and the ultimate preparation of the advanced epoxy materials.

  2. Hydrophobic Modification of Layered Clays and Compatibility for Epoxy Nanocomposites

    Directory of Open Access Journals (Sweden)

    Jiang-Jen Lin


    Full Text Available Recent studies on the intercalation and exfoliation of layered clays with polymeric intercalating agents involving poly(oxypropylene-amines and the particular uses for epoxy nanocomposites are reviewed. For intercalation, counter-ionic exchange reactions of clays including cationic layered silicates and anionic Al-Mg layered double hydroxide (LDH with polymeric organic ions afforded organoclays led to spatial interlayer expansion from 12 to 92 Å (X-ray diffraction as well as hydrophobic property. The inorganic clays of layered structure could be modified by the poly(oxypropyleneamine-salts as the intercalating agents with molecular weights ranging from 230 to 5,000 g/mol. Furthermore, natural montmorillonite (MMT clay could be exfoliated into thin layer silicate platelets (ca. 1 nm thickness in one step by using polymeric types of exfoliating agents. Different lateral dimensions of MMT, synthetic fluorinated Mica and LDH clays had been cured into epoxy nanocomposites. The hydrophobic amine-salt modification resulting in high spacing of layered or exfoliation of individual clay platelets is the most important factor for gaining significant improvements of properties. In particular, these modified clays were reported to gain significant improvements such as reduced coefficient of thermal expansion (CTE, enhanced thermal stability, and hardness. The utilization of these layered clays for initiating the epoxy self-polymerization was also reported to have a unique compatibility between clay and organic resin matrix. However, the matrix domain lacks of covalently bonded crosslink and leads to the isolation of powder material. It is generally concluded that the hydrophobic expansion of the clay inter-gallery spacing is the crucial step for enhancing the compatibility and the ultimate preparation of the advanced epoxy materials.

  3. Hashish Body Packing: A Case Report

    Directory of Open Access Journals (Sweden)

    Manuel Jesus Soriano-Perez


    Full Text Available A 42-year-old African male was brought by the police to the emergency department under suspicion of drug smuggling by body-packing. Plain abdominal radiograph showed multiple foreign bodies within the gastrointestinal tract. Contrast-enhanced abdominal CT confirmed the findings, and the patient admitted to have swallowed “balls” of hashish. Body-packing is a recognized method of smuggling drugs across international borders. Body packers may present to the emergency department because of drug toxicity, intestinal obstruction, or more commonly, requested by law-enforcement officers for medical confirmation or exclusion of suspected body packing.

  4. Comparing the efficacy of mature mud pack and hot pack treatments for knee osteoarthritis. (United States)

    Sarsan, Ayşe; Akkaya, Nuray; Ozgen, Merih; Yildiz, Necmettin; Atalay, Nilgun Simsir; Ardic, Fusun


    The objective of this study is to compare the efficacy of mature mud pack and hot pack therapies on patients with knee osteoarthritis. This study was designed as a prospective, randomized-controlled, and single-blinded clinical trial. Twenty-seven patients with clinical and radiologic evidence of knee osteoarthritis were randomly assigned into two groups and were treated with mature mud packs (n 15) or hot packs (n=12). Patients were evaluated for pain [based on the visual analog scale (VAS)], function (WOMAC, 6 min walking distance), quality of life [Short Form-36 (SF-36)], and serum levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and insulin-like growth factor-1 (IGF-1) at baseline, post-treatment, and 3 and 6~months after treatment. The mud pack group shows a significant improvement in VAS, pain, stifness, and physical function domains of WOMAC. The difference between groups of pain and physical activity domains is significant at post-treatment in favor of mud pack. For a 6 min walking distance, mud pack shows significant improvement, and the difference is significant between groups in favor of mud pack at post-treatment and 3 and 6 months after treatment. Mud pack shows significant improvement in the pain subscale of SF-36 at the third month continuing until the sixth month after the treatment. Significant improvements are found for the social function, vitality/energy, physical role disability, and general health subscales of SF-36 in favor of the mud pack compared with the hot pack group at post-treatment. A significant increase is detected for IGF-1 in the mud pack group 3 months after treatment compared with the baseline, and the difference is significant between groups 3 months after the treatment. Mud pack is a favorable option compared with hotpack for pain relief and for the improvement of functional conditions in treating patients with knee osteoarthritis.

  5. Bubble Movement on Inclined Hydrophobic Surfaces. (United States)

    Kibar, Ali; Ozbay, Ridvan; Sarshar, Mohammad Amin; Kang, Yong Tae; Choi, Chang-Hwan


    The movement of a single air bubble on an inclined hydrophobic surface submerged in water, including both the upward- and downward-facing sides of the surface, was investigated. A planar Teflon sheet with an apparent contact angle of a sessile water droplet of 106° was used as a hydrophobic surface. The volume of a bubble and the inclination angle of a Teflon sheet varied in the ranges 5-40 μL and 0-45°, respectively. The effects of the bubble volume on the adhesion and dynamics of the bubble were studied experimentally on the facing-up and facing-down surfaces of the submerged hydrophobic Teflon sheet, respectively, and compared. The result shows that the sliding angle has an inverse relationship with the bubble volume for both the upward- and downward-facing surfaces. However, at the same given volume, the bubble on the downward-facing surface spreads over a larger area of the hydrophobic surface than the upward-facing surface due to the greater hydrostatic pressure acting on the bubble on the downward-facing surface. This makes the lateral adhesion force of the bubble greater and requires a larger inclination angle to result in sliding.

  6. The new view of hydrophobic free energy. (United States)

    Baldwin, Robert L


    In the new view, hydrophobic free energy is measured by the work of solute transfer of hydrocarbon gases from vapor to aqueous solution. Reasons are given for believing that older values, measured by solute transfer from a reference solvent to water, are not quantitatively correct. The hydrophobic free energy from gas-liquid transfer is the sum of two opposing quantities, the cavity work (unfavorable) and the solute-solvent interaction energy (favorable). Values of the interaction energy have been found by simulation for linear alkanes and are used here to find the cavity work, which scales linearly with molar volume, not accessible surface area. The hydrophobic free energy is the dominant factor driving folding as judged by the heat capacity change for transfer, which agrees with values for solvating hydrocarbon gases. There is an apparent conflict with earlier values of hydrophobic free energy from studies of large-to-small mutations and an explanation is given. Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  7. Nanostructured coatings for super hydrophobic textiles

    Indian Academy of Sciences (India)

    However, silica nanoparticles can be suitably functionalized or can be used as a component of nanocom- posite coating to adhere with cotton surface. Amino functiona- lized silica nanoparticles applied on epoxy functionalized cotton fabric shows excellent super-hydrophobicity (∼170. ◦. ). The functionalization of silica and ...

  8. Deposition and Investigation of Hydrophobic Coatings

    Directory of Open Access Journals (Sweden)

    Safonov Aleksey


    Full Text Available The fluoropolymer coatings of different morphologies are deposited by the HWCVD (Hot Wire CVD method. The effect of activator filament temperature on the structure of fluoropolymer coating is shown. The results of studying the hydrophobic fluoropolymer coatings with different structures, deposited by the HWCVD method, are presented.

  9. Hydrophilic and hydrophobic adsorption on Y zeolites (United States)

    Halasz, Istvan; Kim, Song; Marcus, Bonnie

    The uniform large micropores of hydrothermally stable Y zeolites are used widely to confine both polar and non-polar molecules. This paper compares the physisorption of water, methanol, cyclohexane, benzene and other adsorbates over various Y zeolites. These adsorbents are commercial products with reproducibly controllable physical and chemical characteristics. Results indicate that the type I isotherms typical for micropore adsorption can turn into type II or type III isotherms depending on either or both the hydrophobicity of the adsorbent and the polarity of the adsorbate. Methanol produced a rare type V isotherm not reported over zeolites before. Canonical and grand canonical Monte Carlo molecular simulations with Metropolis importance sampling reproduced the experimental isotherms and showed characteristic geometric patterns for molecules confined in Na-X, Na-Y, dealuminated Y, and ZSM5 structures. Adsorbate-adsorbate interactions seem to determine the micropore condensation of both polar and non-polar molecules. Exchanged ions and lattice defects play a secondary role in shaping the adsorption isotherms. The force field of hydrophobic Y appears to exert an as yet unexplored sieving effect on adsorbates having different dipole moments and partial charge distributions. This mechanism is apparently different from both the monolayer formation controlled adsorption on hydrophobic mesopores and macropores and the polarizability and small-pore opening controlled micropore confinement in hydrophobic ZSM5.

  10. Liquid Water may Stick on Hydrophobic Surfaces

    Indian Academy of Sciences (India)

    IAS Admin

    The behavior of fluid on a solid surface under static and dynamic conditions are usually clubbed together. • On a wetting surface (hydrophilic), liquid water is believed to adhere to the surface causing multilayer sticking. • On a non-wetting surface (hydrophobic), water is believed to glide across the surface leading to slip ...

  11. hydrophobic silica membranes for gas separation

    NARCIS (Netherlands)

    de Vos, R.M.; Maier, Wilhelm F.; Verweij, H.


    The synthesis and properties of hydrophobic silica membranes are described. These membranes show very high gas permeance for small molecules, such as H2, CO2, N2, O2, and CH4, and permselectivities of 20–50 for these gases with respect to SF6 and larger alkanes like C3H8 and i-C4H10. The membranes

  12. Frictional properties of gel engineering materials with laser surface texturing (United States)

    Yamada, Naoya; Gong, Jin; Kabir, M. Hasnat; Makino, Masato; Maekawa, Keisuke; Wada, Masato; Furukawa, Hidemitsu


    Several synthesis methods have been devised to improve the mechanical strength of gels extraordinarily after 2001. It was a trigger to use gels as a new industrial materials, since gels had been considered difficult for industrial materials because of their weakness. In a recent study, we had designed transparency shape memory gels for the first time. Shape memory gels are one of the gels with characteristic networks, and have a shape memory function by copolymerizing an acrylic monomer with a hydrophobic long alkyl side group. It is well known that the mechanical properties such as Young's modulus and friction coefficient of shape memory gels depend on temperature. In this study, we tried to change the frictional properties of shape memory gels by laser surface texturing. Two types of processed surface were prepared. The hexagonal close packed pattern and the square close packed pattern of dimples were formed on the surface of gel sheets with CO2 laser. The intensity of laser was optimized to avoid cutting gels. The friction coefficients of unprocessed gels and two types of processed gels were measured by ball-on-disk method. Measurement partner material was sodalime glass ball. The measurement results of processed gels showed clear differences from unprocessed gels. The friction coefficients of processed gels were larger than unprocessed gels. However, these results specifically showed the velocity dependence. It indicates that surface texturing enable to control the friction coefficient of polymer gels by surface pattern and velocity.

  13. Enhanced water transport and salt rejection through hydrophobic zeolite pores (United States)

    Humplik, Thomas; Lee, Jongho; O’Hern, Sean; Laoui, Tahar; Karnik, Rohit; Wang, Evelyn N.


    The potential of improvements to reverse osmosis (RO) desalination by incorporating porous nanostructured materials such as zeolites into the selective layer in the membrane has spurred substantial research efforts over the past decade. However, because of the lack of methods to probe transport across these materials, it is still unclear which pore size or internal surface chemistry is optimal for maximizing permeability and salt rejection. We developed a platform to measure the transport of water and salt across a single layer of zeolite crystals, elucidating the effects of internal wettability on water and salt transport through the ≈5.5 Å pores of MFI zeolites. MFI zeolites with a more hydrophobic (i.e., less attractive) internal surface chemistry facilitated an approximately order of magnitude increase in water permeability compared to more hydrophilic MFI zeolites, while simultaneously fully rejecting both potassium and chlorine ions. However, our results also demonstrated approximately two orders of magnitude lower permeability compared to molecular simulations. This decreased performance suggests that additional transport resistances (such as surface barriers, pore collapse or blockages due to contamination) may be limiting the performance of experimental nanostructured membranes. Nevertheless, the inclusion of hydrophobic sub-nanometer pores into the active layer of RO membranes should improve both the water permeability and salt rejection of future RO membranes (Fasano et al 2016 Nat. Commun. 7 12762).

  14. Packing circles and spheres on surfaces

    KAUST Repository

    Schiftner, Alexander


    Inspired by freeform designs in architecture which involve circles and spheres, we introduce a new kind of triangle mesh whose faces\\' incircles form a packing. As it turns out, such meshes have a rich geometry and allow us to cover surfaces with circle patterns, sphere packings, approximate circle packings, hexagonal meshes which carry a torsion-free support structure, hybrid tri-hex meshes, and others. We show how triangle meshes can be optimized so as to have the incircle packing property. We explain their relation to conformal geometry and implications on solvability of optimization. The examples we give confirm that this kind of meshes is a rich source of geometric structures relevant to architectural geometry. © 2009 ACM.

  15. Packing circles and spheres on surfaces

    KAUST Repository

    Schiftner, Alexander


    Inspired by freeform designs in architecture which involve circles and spheres, we introduce a new kind of triangle mesh whose faces\\' incircles form a packing. As it turns out, such meshes have a rich geometry and allow us to cover surfaces with circle patterns, sphere packings, approximate circle packings, hexagonal meshes which carry a torsion-free support structure, hybrid tri-hex meshes, and others. We show how triangle meshes can be optimized so as to have the incircle packing property. We explain their relation to conformal geometry and implications on solvability of optimization. The examples we give confirm that this kind of meshes is a rich source of geometric structures relevant to architectural geometry.

  16. Modular vaccine packaging increases packing efficiency (United States)

    Norman, Bryan A.; Rajgopal, Jayant; Lim, Jung; Gorham, Katrin; Haidari, Leila; Brown, Shawn T.; Lee, Bruce Y.


    Background Within a typical vaccine supply chain, vaccines are packaged into individual cylindrical vials (each containing one or more doses) that are bundled together in rectangular “inner packs” for transport via even larger groupings such as cold boxes and vaccine carriers. The variability of vaccine inner pack and vial size may hinder efficient vaccine distribution because it constrains packing of cold boxes and vaccine carriers to quantities that are often inappropriate or suboptimal in the context of country-specific vaccination guidelines. Methods We developed in Microsoft Excel (Microsoft Corp., Redmond, WA) a spreadsheet model that evaluated the impact of different packing schemes for the Benin routine regimen plus the introduction of the Rotarix vaccine. Specifically, we used the model to compare the current packing scheme to that of a proposed modular packing scheme. Results Conventional packing of a Dometic RCW25 that aims to maximize fully-immunized children (FICs) results in 123 FICs and a packing efficiency of 81.93% compared to a maximum of 155 FICs and 94.1% efficiency for an alternative modular packaging system. Conclusions Our analysis suggests that modular packaging systems could offer significant advantages over conventional vaccine packaging systems with respect to space efficiency and potential FICs, when they are stored in standard vaccine carrying devices. This allows for more vaccines to be stored within the same volume while also simplifying the procedures used by field workers to pack storage devices. Ultimately, modular packaging systems could be a simple way to help increase vaccine coverage worldwide. PMID:25957666

  17. Methods for studying transmembrane peptides in bicelles: consequences of hydrophobic mismatch and peptide sequence. (United States)

    Whiles, Jennifer A; Glover, Kerney J; Vold, Regitze R; Komives, Elizabeth A


    We have shown that bicelles prepared from dilauryl phosphatidylcholine (DLPC) and dipalmitoyl phosphatidylcholine (DPPC) align in a magnetic field under conditions similar to the more common dimyristoyl phosphatidylcholine (DMPC) bicelles. In addition, a model transmembrane peptide, P16, with a hydrophobic stretch of 24 A, and specific alanine-d(3) labels, was incorporated into all of the different bicelles. The long-chain phospholipid (DLPC, DMPC, or DPPC) remained unperturbed upon incorporation of the peptide while the quadrupolar splitting of the short-chain phospholipid along the bicelle rim increased by varying degrees in the different bicelle systems. The change in quadrupolar splitting of the short-chain phospholipids was attributed to changes in either fluidity of the planar region of the bicelle or differences in overall lipid packing. When the hydrophobic stretch of the bilayer was 22.8 (DMPC) or 26.3 A (DPPC), the peptide tilt was found to be transmembrane (33-35 degrees with respect to the bicelle normal). When the hydrophobic stretch of the bilayer was 19.5 A (DLPC), the peptide quadrupolar splittings suggested a loss of transmembrane orientation. When tryptophan was incorporated in the middle of the transmembrane region, the transmembrane orientation was also lost. Copyright 2002 Elsevier Science (USA)

  18. The Maximum Resource Bin Packing Problem

    DEFF Research Database (Denmark)

    Boyar, J.; Epstein, L.; Favrholdt, L.M.


    Usually, for bin packing problems, we try to minimize the number of bins used or in the case of the dual bin packing problem, maximize the number or total size of accepted items. This paper presents results for the opposite problems, where we would like to maximize the number of bins used...... or minimize the number or total size of accepted items. We consider off-line and on-line variants of the problems. For the off-line variant, we require that there be an ordering of the bins, so that no item in a later bin fits in an earlier bin. We find the approximation ratios of two natural approximation...... algorithms, First-Fit-Increasing and First-Fit-Decreasing for the maximum resource variant of classical bin packing. For the on-line variant, we define maximum resource variants of classical and dual bin packing. For dual bin packing, no on-line algorithm is competitive. For classical bin packing, we find...

  19. Pharyngeal Packing during Rhinoplasty: Advantages and Disadvantages. (United States)

    Razavi, Majid; Taghavi Gilani, Mehryar; Bameshki, Ali Reza; Behdani, Reza; Khadivi, Ehsan; Bakhshaee, Mahdi


    Controversy remains as to the advantages and disadvantages of pharyngeal packing during septorhinoplasty. Our study investigated the effect of pharyngeal packing on postoperative nausea and vomiting and sore throat following this type of surgery or septorhinoplasty. This clinical trial was performed on 90 American Society of Anesthesiologists (ASA) I or II patients who were candidates for septorhinoplasty. They were randomly divided into two groups. Patients in the study group had received pharyngeal packing while those in the control group had not. The incidence of nausea and vomiting and sore throat based on the visual analog scale (VAS) was evaluated postoperatively in the recovery room as well as at 2, 6 and 24 hours. The incidence of postoperative nausea and vomiting (PONV) was 12.3%, with no significant difference between the study and control groups. Sore throat was reported in 50.5% of cases overall (56.8% on pack group and 44.4% on control). Although the severity of pain was higher in the study group at all times, the incidence in the two groups did not differ significantly. The use of pharyngeal packing has no effect in reducing the incidence of nausea and vomiting and sore throat after surgery. Given that induced hypotension is used as the routine method of anesthesia in septorhinoplasty surgery, with a low incidence of hemorrhage and a high risk of unintended retention of pharyngeal packing, its routine use is not recommended for this procedure.

  20. Packing and size determination of colloidal nanoclusters. (United States)

    Pease, Leonard F; Tsai, De-Hao; Hertz, Joshua L; Zangmeister, Rebecca A; Zachariah, Michael R; Tarlov, Michael J


    Here we demonstrate a rapid and quantitative means to characterize the size and packing structure of small clusters of nanoparticles in colloidal suspension. Clustering and aggregation play important roles in a wide variety of phenomena of both scientific and technical importance, yet characterizing the packing of nanoparticles within small clusters and predicting their aerodynamic size remains challenging because available techniques can lack adequate resolution and sensitivity for clusters smaller than 100 nm (optical techniques), perturb the packing arrangement (electron microscopies), or provide only an ensemble average (light scattering techniques). In this article, we use electrospray-differential mobility analysis (ES-DMA), a technique that exerts electrical and drag forces on the clusters, to determine the size and packing of small clusters. We provide an analytical model to determine the mobility size of various packing geometries based on the projected area of the clusters. Data for clusters aggregated from nominally 10 nm gold particles and nonenveloped viruses of various sizes show good agreement between measured and predicted cluster sizes for close-packed spheres.

  1. Decontamination of pesticide packing using ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, C.L. [Instituto de Pesquisas Energeticas e Nucleares-IPEN-CNEN/SP Av. Lineu Prestes 2.242, 05508-900, Sao Paulo, SP (Brazil)], E-mail:; Mori, M.N.; Kodama, Yasko; Oikawa, H.; Sampa, M.H.O. [Instituto de Pesquisas Energeticas e Nucleares-IPEN-CNEN/SP Av. Lineu Prestes 2.242, 05508-900, Sao Paulo, SP (Brazil)


    The Brazilian agriculture activities have consumed about 288,000 tons of pesticides per year conditioned in about 107,000,000 packing with weight of approximately 23,000 tons. The discharge of empty plastic packing of pesticides can be an environmental concern causing problems to human health, animals, and plants if done without inspection and monitoring. The objective of this work is to study the ionizing radiation effect in the main pesticides used in Brazil for plastic packing decontamination. Among the commercial pesticides, chlorpyrifos has significant importance because of its wide distribution and extensive use and persistence. The radiation-induced degradation of chlorpyrifos in liquid samples and in polyethylene pack was studied by gamma radiolysis. Packing of high-density polyethylene (HDPE) three layer coextruded, named COEX, contaminated with chlorpyrifos, were irradiated using both a multipurpose Co-60 gamma irradiator and a gamma source with 5000 Ci total activity Gamma cell type. The chemical analysis of the chlorpyrifos was made using a gas chromatography associated to the Mass Spectrometry-GCMS from Shimadzu Model QP 5000. Gamma radiation was efficient for removing chlorpyrifos from the plastic packing, in all studied cases.

  2. Competition of electrostatic and hydrophobic interactions between small hydrophobes and model enclosures. (United States)

    Wang, Lingle; Friesner, Richard A; Berne, B J


    The binding affinity between a probe hydrophobic particle and model hydrophobic plates with different charge (or dipole) densities in water was investigated through molecular dynamics simulation free-energy perturbation calculations. We observed a reduced binding affinity when the plates are charged, in agreement with previous findings. With increased charge density, the plates can change from "hydrophobic like" (pulling the particle into the interplate region) to "hydrophilic like" (ejecting the particle out of the interplate region), demonstrating the competition between hydrophobic and electrostatic interactions. The reduction of the binding affinity is quadratically dependent on the magnitude of the charge for symmetric systems, but linear and cubic terms also make a contribution for asymmetric systems. Statistical perturbation theory explains these results and shows when and why implicit solvent models fail.

  3. Glottotecnologie didattiche per i migranti L’italiano fra le altre lingue nel progetto L-Pack (Citizenship Language Pack for Migrants in Europe

    Directory of Open Access Journals (Sweden)

    Pierangela Diadori


    Full Text Available Teaching languages to migrants through ICT L-Pack Project for Italian and other languages (Citizenship Language Pack for Migrants in EuropeThe most recent trends in technology and the internet, commonly called Web 2.0., have determined new concepts in teaching and learning that involve autonomy, multimodality and flexibility. New approaches to ‘knowledge by technology’ are changing both teachers’ and learners’ roles, responding to their different aims and needs. At the same time, nearly 4 million people are presently involved in massive migration processes all over Europe, coming either from outside Europe or from another EU member state. The EU policies on migrants state the importance of a basic knowledge of the host country’s language, history and institutions for an effective integration process, and EU governments are expected to contribute to this aim. This paper describes the European Project ‘L-PACK: Citizenship Language Pack For Migrants in Europe’ (2011-2016, whose main aim consisted in developing a series of internet video texts, accompanied with materials and resources to lead adult migrants to A2 level (according to QCER levels scale in different EU languages. The project has been developed in two main stages. In the first part of the programme, called L-Pack 1, from 2011 to 2013, the languages were Italian, Spanish, German, Lithuanian, Greek and Czech. In the second part, called L-Pack 2 extended, from 2014 to 2016, the project added English and French and was integrated with new resources and tools. The L-PACK course, which consists of 60 short video dialogues from everyday life, supported by comprehension activities and linguistic explanation and rules, is totally free and available through Youtube, Wikibooks and Soundcloud. The dedicated website was visited by 120.000 users from 146 countries in the period 2011-2016. L-Pack teaching materials have also been used by teachers in classroom

  4. High-temperature separation with polymer-coated fiber in packed capillary gas chromatography. (United States)

    Saito, Yoshihiro; Ogawa, Mitsuhiro; Imaizumi, Motohiro; Ban, Kazuhiro; Abe, Akira; Takeichi, Tsutomu; Wada, Hiroo; Jinno, Kiyokatsu


    High-temperature gas chromatographic separation of several synthetic polymer mixtures with Dexsil-coated fiber-packed columns was studied. A bundle of heat-resistant filaments, Zylon, was longitudinally packed into a short metal capillary, followed by the conventional coating process with Dexsil 300 material. Prior to the packing process the metal capillary was deactivated by the formation of a silica layer. The typical size of the resulting column was 0.3-mm i.d., 0.5-mm o.d., 1-m length, and packed with about 170 filaments of the Dexsil-coated Zylon. The column temperature could be elevated up to 450 degrees C owing to the good thermal stability of the fiber, Dexsil coating, and metal capillary; furthermore, this allowed the separation of low-volatile compounds to be studied.

  5. Staphylococcus epidermidis adhesion on hydrophobic and hydrophilic textured biomaterial surfaces. (United States)

    Xu, Li-Chong; Siedlecki, Christopher A


    It is of great interest to use nano- or micro-structured surfaces to inhibit microbial adhesion and biofilm formation and thereby to prevent biomaterial-associated infection, without modification of the surface chemistry or bulk properties of the materials and without use of the drugs. Our previous study showed that a submicron textured polyurethane surface can inhibit staphylococcal bacterial adhesion and biofilm formation. To further understand the effect of the geometry of textures on bacterial adhesion as well as the underlying mechanism, in this study, submicron and micron textured polyurethane surfaces featuring ordered arrays of pillars were fabricated and modified to have different wettabilities. All the textured surfaces were originally hydrophobic and showed significant reductions in Staphylococcus epidermidis RP62A adhesion in phosphate buffered saline or 25% platelet poor plasma solutions under shear, as compared to smooth surfaces. After being subjected to an air glow discharge plasma treatment, all polyurethane surfaces were modified to hydrophilic, and reductions in bacterial adhesion on surfaces were subsequently found to be dependent on the size of the patterns. The submicron patterned surfaces reduced bacterial adhesion, while the micron patterned surfaces led to increased bacterial adhesion. The extracellular polymeric substances (EPS) from the S. epidermidis cell surfaces were extracted and purified, and were coated on a glass colloidal surface so that the adhesion force and separation energy in interactions of the EPS and the surface could be measured by colloidal probe atomic force microscopy. These results were consistent with the bacterial adhesion observations. Overall, the data suggest that the increased surface hydrophobicity and the decreased availability of the contact area contributes to a reduction in bacterial adhesion to the hydrophobic textured surfaces, while the availability of the contact area is the primary determinant factor

  6. Hydrophobization of track membrane surface by ion-plasma sputtering method (United States)

    Kuklin, I. E.; Khlebnikov, N. A.; Barashev, N. R.; Serkov, K. V.; Polyakov, E. V.; Zdorovets, M. V.; Borgekov, D. B.; Zhidkov, I. S.; Cholakh, S. O.; Kozlovskiy, A. L.


    This article reviews the possibility of applying inorganic coatings of metal compounds on PTM by ion-plasma sputtering. The main aim of this research is to increase the contact angle of PTM surfaces and to impart the properties of a hydrophobic material to it. After the modification, the initial contact angle increased from 70° to 120°.

  7. Immobilization of molecular cobalt electrocatalyst by hydrophobic interaction with hematite photoanode for highly stable oxygen evolution

    KAUST Repository

    Joya, Khurram


    A unique modification of a hematite photoanode with perfluorinated Co-phthalocyanine (CoFPc) by strong binding associated with hydrophobic interaction is demonstrated. The resultant molecular electrocatalyst – hematite photoanode hybrid material showed significant onset shift and high stability for photoelectrochemical oxidation evolution reaction (OER).

  8. Ultra fast laser machined hydrophobic stainless ateel surface for drag reduction in laminar flows

    NARCIS (Netherlands)

    Jagdheesh, R.; Pathiraj, B.; Martin, A.G.; Del Cerro, D.A.; Lammertink, R.G.H.; Lohse, D.; Huis in 't Veld, A.J.; Römer, G.R.B.E.


    Hydrophobic surfaces have attracted much attention due to their potential in microfluidics, lab on chip devices and as functional surfaces for the automotive and aerospace industry. The combination of a dual scale roughness with an inherent low-surface-energy coating material is the pre-requisite

  9. Hydrophobic polymer monoliths as novel phase separators: Application in continuous liquid-liquid extraction systems

    NARCIS (Netherlands)

    Peroni, D.; Vanhoutte, D.; Vilaplana, F.; Schoenmakers, P.; de Koning, S.; Janssen, H.-G.


    Hydrophobic macroporous polymer monoliths are shown to be interesting materials for the construction of "selective solvent gates". With the appropriate surface chemistry and porous properties the monoliths can be made permeable only for apolar organic solvents and not for water. Different poly(butyl

  10. Exceptional Hydrophobicity of a Large-Pore Metal-Organic Zeolite

    NARCIS (Netherlands)

    He, C.T.; Jiang, L.; Ye, Z.M.; Krishna, R.; Zhong, Z.S.; Liao, P.Q.; Xu, J.; Ouyang, G.; Zhang, J.P.; Chen, X.M.


    Porous materials combining high hydrophobicity, large surface area, as well as large and uniform pore size are very useful but rare. The nanoporous zeolitic metal azolate framework, RHO-[Zn(eim)(2)] (MAF-6, Heim = 2-ethylimidazole), is an attractive candidate but thought to be unobtainable/unstable.

  11. Comparing side chain packing in soluble proteins, protein-protein interfaces, and transmembrane proteins. (United States)

    Gaines, J C; Acebes, S; Virrueta, A; Butler, M; Regan, L; O'Hern, C S


    We compare side chain prediction and packing of core and non-core regions of soluble proteins, protein-protein interfaces, and transmembrane proteins. We first identified or created comparable databases of high-resolution crystal structures of these 3 protein classes. We show that the solvent-inaccessible cores of the 3 classes of proteins are equally densely packed. As a result, the side chains of core residues at protein-protein interfaces and in the membrane-exposed regions of transmembrane proteins can be predicted by the hard-sphere plus stereochemical constraint model with the same high prediction accuracies (>90%) as core residues in soluble proteins. We also find that for all 3 classes of proteins, as one moves away from the solvent-inaccessible core, the packing fraction decreases as the solvent accessibility increases. However, the side chain predictability remains high (80% within 30°) up to a relative solvent accessibility, rSASA≲0.3, for all 3 protein classes. Our results show that ≈40% of the interface regions in protein complexes are "core", that is, densely packed with side chain conformations that can be accurately predicted using the hard-sphere model. We propose packing fraction as a metric that can be used to distinguish real protein-protein interactions from designed, non-binding, decoys. Our results also show that cores of membrane proteins are the same as cores of soluble proteins. Thus, the computational methods we are developing for the analysis of the effect of hydrophobic core mutations in soluble proteins will be equally applicable to analyses of mutations in membrane proteins. © 2018 Wiley Periodicals, Inc.

  12. An efficient block-discriminant identification of packed malware

    Indian Academy of Sciences (India)

    Modern malware hide their malicious payload by applying packing mechanism. Packing tools ... Despite being just a variant of known malware, the packed malware invalidates the traditional signature based malware detection as packing tools create an envelope of packer code around the original base malware. Therefore ...

  13. 27 CFR 24.308 - Bottled or packed wine record. (United States)


    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Bottled or packed wine... BUREAU, DEPARTMENT OF THE TREASURY LIQUORS WINE Records and Reports § 24.308 Bottled or packed wine record. A proprietor who bottles, packs, or receives bottled or packed beverage wine in bond shall...

  14. Hydrophobization of inorganic oxide surfaces using dimethylsilanediol. (United States)

    Lin, Ying; Wang, Liming; Krumpfer, Joseph W; Watkins, James J; McCarthy, Thomas J


    Dimethylsilanediol is a stable crystalline solid that was described in 1953. As the monomer of an important class of commercial products (poly(dimethylsiloxanes)-silicones, PDMS) and as a simple molecule in its own right (the silicon analog of acetone hydrate), it has been neglected by several fields of fundamental and applied research including the hydrophobization of inorganic oxide surfaces. We report that dimethylsilanediol is a useful reagent for the surface modification (hydrophobization) of oxidized silicon and other oxidized metal surfaces and compare the wetting properties of modified solids with those of conventionally modified surfaces. That water is the only byproduct of this modification reaction suggests that this and likely other silanediols are useful surface-modification agents, particularly when substrate corrosion or the competitive adsorption of byproducts is an issue. We note that dimethylsilanediol is volatile with a significant vapor pressure at room temperature. Vapor-phase surface modifications are also reported.

  15. Hydrophobic Solvation : A 2D IR Spectroscopic Inquest

    NARCIS (Netherlands)

    Bakulin, Artem A.; Liang, Chungwen; Jansen, Thomas La Cour; Wiersma, Douwe A.; Bakker, Huib J.; Pshenichnikov, Maxim S.

    For decades, the enigma of the hydrophobic force has captured the imagination of scientists. in particular, Frank and Evans' idea that the hydrophobic effect was mainly due to some kind of "iceberg" formation around a hydrophobic solute stimulated many experiments and molecular dynamics simulation

  16. Hydrophobic solvation: A 2D IR spectroscopic inquest

    NARCIS (Netherlands)

    Bakulin, A.A.; Liang, C.; La Cour Jansen, T.; Wiersma, D.A.; Bakker, H.J.; Pshenichnikov, M.S.


    For decades, the enigma of the hydrophobic force has captured the imagination of scientists. in particular, Frank and Evans' idea that the hydrophobic effect was mainly due to some kind of "iceberg" formation around a hydrophobic solute stimulated many experiments and molecular dynamics simulation

  17. Assessing support packs from an occupational hygiene perspective

    CSIR Research Space (South Africa)

    Pretorius, Cecilia J


    Full Text Available Support packs in the mining industry are used to support the hangingwall from imminent collapse where the rock and/or soil have been excavated in mining activities. Mines generally use explosives to move the rock face while following the reef... fraction CS is a problem to employees and users of the products only once the bulk material becomes airborne. The Metrology Working Group of the Industrial Minerals Association in Europe (IMA-EU) has developed the Size-Weighted Poten- tial Respirable...

  18. On Controlling the Hydrophobicity of Nanostructured Zinc-Oxide Layers Grown by Pulsed Electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Klochko, N. P., E-mail:; Klepikova, K. S.; Kopach, V. R.; Khrypunov, G. S. [National Technical University “Kharkiv Polytechnic Institute” (Ukraine); Myagchenko, Yu. O.; Melnychuk, E. E. [Taras Shevchenko National University of Kyiv (Ukraine); Lyubov, V. M.; Kopach, A. V. [National Technical University “Kharkiv Polytechnic Institute” (Ukraine)


    The possibility of fabricating highly hydrophobic nanostructured zinc-oxide layers by the inexpensive method of pulsed electrodeposition from aqueous solutions without water-repellent coatings, adapted for large-scale production, is shown. The conditions of the deposition of highly hydrophobic nanostructured zinc-oxide layers exhibiting the “rose-petal” effect with specific morphology, optical properties, crystal structure and texture are determined. The grown ZnO nanostructures are promising for micro- and nanoelectronics as an adaptive material able to reversibly transform to the hydrophilic state upon exposure to ultraviolet radiation.

  19. Adsorption of dextrin on hydrophobic minerals. (United States)

    Beaussart, Audrey; Mierczynska-Vasilev, Agnieszka; Beattie, David A


    The adsorption of dextrin on talc, molybdenite, and graphite (three naturally hydrophobic minerals) has been compared. Adsorption isotherms and in situ tapping mode atomic force microscope (TMAFM) imaging have enabled polymer adsorbed amount and morphology of the adsorbed layer (area coverage and polymer domain size) to be determined and also the amount of hydration water in the structure of the adsorbed layer. The effect of the polymer on the mineral contact angles, measured by the captive bubble method on cleaved mineral surfaces, indicates clear correlations between the hydrophobicity reduction of the minerals, the adsorbed amount, and the surface coverage of the adsorbed polymer. Predictions of the flotation recovery of the treated mineral phases have been confirmed by performing batch flotation experiments. The influence of the polymer surface coverage on flotation recovery has highlighted the importance of this key parameter in the predictions of depressant efficiency. The roles of the initial hydrophobicity and the surface structure of the mineral basal plane in determining adsorption parameters and flotation response of the polymer-treated minerals are also discussed.

  20. Hydrophobic-hydrophilic forces in protein folding. (United States)

    Durell, Stewart R; Ben-Naim, Arieh


    The process of protein folding is obviously driven by forces exerted on the atoms of the amino-acid chain. These forces arise from interactions with other parts of the protein itself (direct forces), as well as from interactions with the solvent (solvent-induced forces). We present a statistical-mechanical formalism that describes both these direct and indirect, solvent-induced thermodynamic forces on groups of the protein. We focus on 2 kinds of protein groups, commonly referred to as hydrophobic and hydrophilic. Analysis of this result leads to the conclusion that the forces on hydrophilic groups are in general stronger than on hydrophobic groups. This is then tested and verified by a series of molecular dynamics simulations, examining both hydrophobic alkanes of different sizes and hydrophilic moieties represented by polar-neutral hydroxyl groups. The magnitude of the force on assemblies of hydrophilic groups is dependent on their relative orientation: with 2 to 4 times larger forces on groups that are able to form one or more direct hydrogen bonds. © 2017 Wiley Periodicals, Inc.

  1. Magnetic hydrophobic nanocomposites: Silica aerogel/maghemite

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza Zelis, P. [Departamento de Fisica-IFLP, Universidad Nacional de La Plata-CONICET (Argentina); Fernandez van Raap, M.B., E-mail: [Departamento de Fisica-IFLP, Universidad Nacional de La Plata-CONICET (Argentina); Socolovsky, L.M. [Laboratorio de Solidos Amorfos, INTECIN, Universidad de Buenos Aires-CONICET (Argentina); Leyva, A.G. [Div. Materia condensada, CNEA- ECyT-UNSAM, Buenos Aires (Argentina); Sanchez, F.H. [Departamento de Fisica-IFLP, Universidad Nacional de La Plata-CONICET (Argentina)


    Magnetic hydrophobic aerogels (MHA) in the form of nanocomposites of silica and maghemite ({gamma}-Fe{sub 2}O{sub 3}) were prepared by one step sol-gel procedure followed by supercritical solvent extraction. Silica alcogels were obtained from TEOS, MTMS, methanol and H{sub 2}O, and Fe(III) nitrate as magnetic precursor. The hydrophobic property was achieved using the methytrimethoxysilane (MTMS) as co-precursor for surface modification. The so produced nanocomposite aerogels are monolithic, hydrophobic and magnetic. The interconnected porous structure hosts {approx}6 nm size {gamma}-Fe{sub 2}O{sub 3} particles, has a mean pore diameter of 5 nm, and a specific surface area (SSA) of 698 m Superscript-Two /g. Medium range structure of MHA is determined by SAXS, which displays the typical fractal power law behavior with primary particle radius of {approx}1 nm. Magnetic properties of the nanoparticle ensembles hosted in them are studied by means of dc-magnetometry.

  2. Enhanced Pest Ant Control With Hydrophobic Bait. (United States)

    Vander Meer, R K; Milne, D E


    The red imported fire ant, Solenopsis invicta (Buren), left most of its natural enemies behind in South America when it arrived in Mobile, AL, in the 1930s and spread rapidly throughout the southeastern United States, reaching population levels up to 10 times those found in South America. The large population densities and propensity for disturbed habitats led to direct conflict with human activities. Bait control methods were first developed for fire ants in the early 1960s and little has changed in the subsequent decades, despite the drawback that the bait carrier rapidly breaks down when wet. The southeast United States is wet; thus, bait labels have various guidance-restricting applications based on potential wet conditions. Here we compare a hydrophobic fire ant bait to the equivalent standard bait formulation and demonstrate in a paired-mound field experiment under natural wet conditions in Florida (heavy dew on ground), a significant advantage for the hydrophobic bait. An effective hydrophobic ant bait would extend the utility of current bait insecticides to wet conditions and also fill an important gap in our ability to control invasive pest ant species that thrive in wet tropical and subtropical habitats, e.g., Wasmannia auropunctata (Roger), the little fire ant. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by US Government employees and is in the public domain in the US.

  3. Direct contact condensation in packed beds

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yi; Klausner, James F.; Mei, Renwei; Knight, Jessica [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611 (United States)


    A diffusion driven desalination process was recently described where a very effective direct contact condenser with a packed bed is used to condense water vapor out of an air/vapor mixture. A laboratory scale direct contact condenser has been fabricated as a twin tower structure with two stages, co-current and countercurrent. Experiments have been operated in each stage with respective saturated air inlet temperatures of 36, 40 and 43{sup o}C. The temperature and humidity data have been collected at the inlet and exit of the packed bed for different water to air mass flow ratios that vary between 0 and 2.5. A one-dimensional model based on conservation principles has been developed, which predicts the variation of temperature, humidity, and condensation rate through the condenser stages. Agreement between the model and experiments is very good. It is observed that the countercurrent flow stage condensation effectiveness is significantly higher than that for the co-current stage. The condensation heat and mass transfer rates were found to decrease when water blockages occur within the packed bed. Using high-speed digital cinematography, it was observed that this problem can occur at any operating condition, and is dependent on the packing surface wetting characteristics. This observation is used to explain the requirement for two different empirical constants, depending on packing diameter, suggested by Onda for the air side mass transfer coefficient correlation. (author)

  4. Standard Test Method for Hydrophobic Surface Films by the Water-Break Test

    CERN Document Server

    American Society for Testing and Materials. Philadelphia


    1.1 This test method covers the detection of the presence of hydrophobic (nonwetting) films on surfaces and the presence of hydrophobic organic materials in processing ambients. When properly conducted, the test will enable detection of molecular layers of hydrophobic organic contaminants. On very rough or porous surfaces, the sensitivity of the test may be significantly decreased. 1.2 The values stated in SI units are to be regarded as the standard. The inch-pound values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  5. Plasma jet array treatment to improve the hydrophobicity of contaminated HTV silicone rubber (United States)

    Zhang, Ruobing; Han, Qianting; Xia, Yan; Li, Shuang


    An atmospheric-pressure plasma jet array specially designed for HTV silicone rubber treatment is reported in this paper. Stable plasma containing highly energetic active particles was uniformly generated in the plasma jet array. The discharge pattern was affected by the applied voltage. The divergence phenomenon was observed at low gas flow rate and abated when the flow rate increased. Temperature of the plasma plume is close to room temperature which makes it feasible for temperature-sensitive material treatment. Hydrophobicity of contaminated HTV silicone rubber was significantly improved after quick exposure of the plasma jet array, and the effective treatment area reached 120 mm × 50 mm (length × width). Reactive particles in the plasma accelerate accumulation of the hydrophobic molecules, namely low molecular weight silicone chains, on the contaminated surface, which result in a hydrophobicity improvement of the HTV silicone rubber.

  6. Standard Test Method for Hydrophobic Surface Films by the Atomizer Test

    CERN Document Server

    American Society for Testing and Materials. Philadelphia


    1.1 This test method covers the detection of the presence of hydrophobic (nonwetting) films on surfaces and the presence of hydrophobic organic materials in processing ambients. When properly conducted, the test will enable detection of fractional molecular layers of hydrophobic organic contaminants. On very rough or porous surfaces the sensitivity of the test may be significantly decreased. 1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  7. Peptides that form β-sheets on hydrophobic surfaces accelerate surface-induced insulin amyloidal aggregation. (United States)

    Nault, Laurent; Vendrely, Charlotte; Bréchet, Yves; Bruckert, Franz; Weidenhaupt, Marianne


    Interactions between proteins and material or cellular surfaces are able to trigger protein aggregation in vitro and in vivo. The human insulin peptide segment LVEALYL is able to accelerate insulin aggregation in the presence of hydrophobic surfaces. We show that this peptide needs to be previously adsorbed on a hydrophobic surface to induce insulin aggregation. Moreover, the study of different mutant peptides proves that its sequence is less important than the secondary structure of the adsorbed peptide on the surface. Indeed, these pro-aggregative peptides act by providing stable β-sheets to incoming insulin molecules, thereby accelerating insulin adsorption locally and facilitating the conformational changes required for insulin aggregation. Conversely, a peptide known to form α-helices on hydrophobic surfaces delays insulin aggregation. Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  8. Synthesis and texturization processes of (super)-hydrophobic fluorinated surfaces by atmospheric plasma

    CERN Document Server

    Hubert, Julie; Dufour, Thierry; Vandencasteele, Nicolas; Reniers, François; Viville, Pascal; Lazzaroni, Roberto; Raes, M; Terryn, Herman


    The synthesis and texturization processes of fluorinated surfaces by means of atmospheric plasma are investigated and presented through an integrated study of both the plasma phase and the resulting material surface. Three methods enhancing the surface hydrophobicity up to the production of super-hydrophobic surfaces are evaluated: (i) the modification of a polytetrafluoroethylene (PTFE) surface, (ii) the plasma deposition of fluorinated coatings and (iii) the incorporation of nanoparticles into those fluorinated films. In all the approaches, the nature of the plasma gas appears to be a crucial parameter for the desired property. Although a higher etching of the PTFE surface can be obtained with a pure helium plasma, the texturization can only be created if O2 is added to the plasma, which simultaneously decreases the total etching. The deposition of CxFy films by a dielectric barrier discharge leads to hydrophobic coatings with water contact angles (WCAs) of 115{\\textdegree}, but only the filamentary argon d...

  9. Hydrophobization by Means of Nanotechnology on Greek Sandstones Used as Building Facades

    Directory of Open Access Journals (Sweden)

    Georgios Karagiannis


    Full Text Available Modern sustainable architecture indicates the use of local natural stones for building. Greek sandstones from Epirus (Demati, Greece, EN 12440 used as building facades meet aesthetic and have high mechanical properties, but the inevitable interaction between stone materials and natural or anthropogenic weathering factors controls the type, and extent of stone damages. In the present paper, samples of sandstone were treated with a conventional hydrophobic product and four solutions of the same product, enriched with nanosilica of different concentrations. The properties of the treated samples, such as porosity and pore size distribution, microstructure, static contact angle of a water droplet, and durability to deterioration cycles (freeze-thaw were recorded and conclusions were drawn. The research indicates the increased hydrophobic properties in nanosilica solutions but also the optimum content in nanoparticles that provides hydrophobicity without altering the properties of the stone.

  10. Ecology of southern ocean pack ice. (United States)

    Brierley, Andrew S; Thomas, David N


    Around Antarctica the annual five-fold growth and decay of sea ice is the most prominent physical process and has a profound impact on marine life there. In winter the pack ice canopy extends to cover almost 20 million square kilometres--some 8% of the southern hemisphere and an area larger than the Antarctic continent itself (13.2 million square kilometres)--and is one of the largest, most dynamic ecosystems on earth. Biological activity is associated with all physical components of the sea-ice system: the sea-ice surface; the internal sea-ice matrix and brine channel system; the underside of sea ice and the waters in the vicinity of sea ice that are modified by the presence of sea ice. Microbial and microalgal communities proliferate on and within sea ice and are grazed by a wide range of proto- and macrozooplankton that inhabit the sea ice in large concentrations. Grazing organisms also exploit biogenic material released from the sea ice at ice break-up or melt. Although rates of primary production in the underlying water column are often low because of shading by sea-ice cover, sea ice itself forms a substratum that provides standing stocks of bacteria, algae and grazers significantly higher than those in ice-free areas. Decay of sea ice in summer releases particulate and dissolved organic matter to the water column, playing a major role in biogeochemical cycling as well as seeding water column phytoplankton blooms. Numerous zooplankton species graze sea-ice algae, benefiting additionally because the overlying sea-ice ceiling provides a refuge from surface predators. Sea ice is an important nursery habitat for Antarctic krill, the pivotal species in the Southern Ocean marine ecosystem. Some deep-water fish migrate to shallow depths beneath sea ice to exploit the elevated concentrations of some zooplankton there. The increased secondary production associated with pack ice and the sea-ice edge is exploited by many higher predators, with seals, seabirds and whales

  11. Generalized network improvement and packing problems

    CERN Document Server

    Holzhauser, Michael


    Michael Holzhauser discusses generalizations of well-known network flow and packing problems by additional or modified side constraints. By exploiting the inherent connection between the two problem classes, the author investigates the complexity and approximability of several novel network flow and packing problems and presents combinatorial solution and approximation algorithms. Contents Fractional Packing and Parametric Search Frameworks Budget-Constrained Minimum Cost Flows: The Continuous Case Budget-Constrained Minimum Cost Flows: The Discrete Case Generalized Processing Networks Convex Generalized Flows Target Groups Researchers and students in the fields of mathematics, computer science, and economics Practitioners in operations research and logistics The Author Dr. Michael Holzhauser studied computer science at the University of Kaiserslautern and is now a research fellow in the Optimization Research Group at the Department of Mathematics of the University of Kaiserslautern.

  12. Wolf Pack Algorithm for Unconstrained Global Optimization

    Directory of Open Access Journals (Sweden)

    Hu-Sheng Wu


    Full Text Available The wolf pack unites and cooperates closely to hunt for the prey in the Tibetan Plateau, which shows wonderful skills and amazing strategies. Inspired by their prey hunting behaviors and distribution mode, we abstracted three intelligent behaviors, scouting, calling, and besieging, and two intelligent rules, winner-take-all generation rule of lead wolf and stronger-survive renewing rule of wolf pack. Then we proposed a new heuristic swarm intelligent method, named wolf pack algorithm (WPA. Experiments are conducted on a suit of benchmark functions with different characteristics, unimodal/multimodal, separable/nonseparable, and the impact of several distance measurements and parameters on WPA is discussed. What is more, the compared simulation experiments with other five typical intelligent algorithms, genetic algorithm, particle swarm optimization algorithm, artificial fish swarm algorithm, artificial bee colony algorithm, and firefly algorithm, show that WPA has better convergence and robustness, especially for high-dimensional functions.

  13. Spontaneous crystallization in athermal polymer packings. (United States)

    Karayiannis, Nikos Ch; Foteinopoulou, Katerina; Laso, Manuel


    We review recent results from extensive simulations of the crystallization of athermal polymer packings. It is shown that above a certain packing density, and for sufficiently long simulations, all random assemblies of freely-jointed chains of tangent hard spheres of uniform size show a spontaneous transition into a crystalline phase. These polymer crystals adopt predominantly random hexagonal close packed morphologies. An analysis of the local environment around monomers based on the shape and size of the Voronoi polyhedra clearly shows that Voronoi cells become more spherical and more symmetric as the system transits to the ordered state. The change in the local environment leads to an increase in the monomer translational contribution to the entropy of the system, which acts as the driving force for the phase transition. A comparison of the crystallization of hard-sphere polymers and monomers highlights similarities and differences resulting from the constraints imposed by chain connectivity.

  14. Spontaneous Crystallization in Athermal Polymer Packings

    Directory of Open Access Journals (Sweden)

    Nikos Ch. Karayiannis


    Full Text Available We review recent results from extensive simulations of the crystallization of athermal polymer packings. It is shown that above a certain packing density, and for sufficiently long simulations, all random assemblies of freely-jointed chains of tangent hard spheres of uniform size show a spontaneous transition into a crystalline phase. These polymer crystals adopt predominantly random hexagonal close packed morphologies. An analysis of the local environment around monomers based on the shape and size of the Voronoi polyhedra clearly shows that Voronoi cells become more spherical and more symmetric as the system transits to the ordered state. The change in the local environment leads to an increase in the monomer translational contribution to the entropy of the system, which acts as the driving force for the phase transition. A comparison of the crystallization of hard-sphere polymers and monomers highlights similarities and differences resulting from the constraints imposed by chain connectivity.

  15. High-throughput screening of PLGA thin films utilizing hydrophobic fluorescent dyes for hydrophobic drug compounds. (United States)

    Steele, Terry W J; Huang, Charlotte L; Kumar, Saranya; Widjaja, Effendi; Chiang Boey, Freddy Yin; Loo, Joachim S C; Venkatraman, Subbu S


    Hydrophobic, antirestenotic drugs such as paclitaxel (PCTX) and rapamycin are often incorporated into thin film coatings for local delivery using implantable medical devices and polymers such as drug-eluting stents and balloons. Selecting the optimum coating formulation through screening the release profile of these drugs in thin films is time consuming and labor intensive. We describe here a high-throughput assay utilizing three model hydrophobic fluorescent compounds: fluorescein diacetate (FDAc), coumarin-6, and rhodamine 6G that were incorporated into poly(d,l-lactide-co-glycolide) (PLGA) and PLGA-polyethylene glycol films. Raman microscopy determined the hydrophobic fluorescent dye distribution within the PLGA thin films in comparison with that of PCTX. Their subsequent release was screened in a high-throughput assay and directly compared with HPLC quantification of PCTX release. It was observed that PCTX controlled-release kinetics could be mimicked by a hydrophobic dye that had similar octanol-water partition coefficient values and homogeneous dissolution in a PLGA matrix as the drug. In particular, FDAc was found to be the optimal hydrophobic dye at modeling the burst release as well as the total amount of PCTX released over a period of 30 days. Copyright © 2011 Wiley-Liss, Inc.

  16. Super-hydrophobic graphene coated polyurethane (GN@PU) sponge with great oil-water separation performance (United States)

    Zhang, Xiaotan; Liu, Dongyan; Ma, Yuling; Nie, Jing; Sui, Guoxin


    The graphene/polyurethane (GN@PU) sponge was prepared via simple dip-coating PU sponges in graphene aqueous suspension containing cellulose nanowhiskers (CNWs), where CNWs played a vital role to facilitate the uniform graphene sheets coated on the skeletons of polyurethane sponge (PU). The super-hydrophobic GN@PU sponge was obtained by optimizing the ratio of GN and CNWs to choose the final coating suspensions of GN/CNWs mixture or pure graphene. The GN@PU sponge showed densely packed graphene sheets, contributing super-hydrophobicity to the sponge with water contact angle of 152° and a large lubricating oil absorption value of 31 g g-1. The elasticity, mechanical durability, thermal and chemical stability were all found to be improved after coating with the thin GN layers. Moreover, the GN@PU sponges possess outstanding recyclability and stability since no decline in absorption efficiency was observed after more than 100 cycles.

  17. Dewetting and hydrophobic interaction in physical and biological systems. (United States)

    Berne, Bruce J; Weeks, John D; Zhou, Ruhong


    Hydrophobicity manifests itself differently on large and small length scales. This review focuses on large-length-scale hydrophobicity, particularly on dewetting at single hydrophobic surfaces and drying in regions bounded on two or more sides by hydrophobic surfaces. We review applicable theories, simulations, and experiments pertaining to large-scale hydrophobicity in physical and biomolecular systems and clarify some of the critical issues pertaining to this subject. Given space constraints, we cannot review all the significant and interesting work in this active field.

  18. Effects of hydrophobic chain length on temperature dependence of monolayer behavior of ester-type tartaric geminis. (United States)

    Kawase, Tokuzo; Saito, Isao; Oida, Tatsuo


    Ester-type tartaric gemini amphiphiles bearing two carboxyl groups and two hydrophobic alkanoyl groups were prepared from L-tartaric acid, and the pressure-area (π-A) isotherms for a series of symmetric tartaric gemini amphiphiles were measured by the conventional film-balance technique. The effects of the length of the hydrophobic alkanoyl chains and of the subphase temperature (T(sub)) on the π-A isotherms for these compounds were examined. As the length of the hydrophobic alkyl chain increased, a more tightly packed monolayer was formed at the air-water interface. The melting temperature (T(m)) of the monolayer on the water surface was evaluated from the subphase temperature (T(sub)) dependence of the monolayer static elasticity ε(s), based on a π-A isotherm. A clear relationship between T(m) and hydrophobic carbon number (n) was observed for 2D monolayers of tartaric geminis on water surfaces, as well as for fatty acids and/or 3D solids.

  19. Electrohydrodynamic behavior of water droplets on a horizontal super hydrophobic surface and its self-cleaning application (United States)

    Li, Jian; Wei, Yuan; Huang, Zhengyong; Wang, Feipeng; Yan, Xinzhu; Wu, Zhuolin


    Moisture is a significant factor that affects the insulation performance of outdoor high-voltage insulators in power systems. Accumulation of water droplets on insulators causes severe problems such as flashover of insulators and power outage. In this study, we develop a method to fabricate a micro/nano hierarchical super hydrophobic surface. The as-prepared super hydrophobic surface exhibits a water contact angle (WCA) of 160.4 ± 2°, slide angle (SA) less than 1° and surface free energy (SFE) of 5.99 mJ/m2. We investigated the electrohydropdynamic behavior of water droplet on a horizontal super hydrophobic surface compared with hydrophobic RTV silicone rubber surface which was widely used as anti-pollution coating or shed material of composite insulator. Results show that water droplet tended to a self-propelled motion on the super hydrophobic surface while it tended to elongate and break up on the RTV surface. The micro/nano hierarchical surface structure and chemical components with low surface free energy of the super hydrophobic surface jointly contributed to the reduction of skin fraction drag and subsequently made it possible for the motion of water droplet driven by electric field. Furthermore, the self-propelled motion of water droplets could also sweep away contaminations along its moving trace, which provides super hydrophobic surface a promising anti-pollution prospect in power systems.

  20. Tribological behaviour of nano-composite UHMWPE on ski surfaces and the role of hydrophobicity


    Backéus, Anders


    Ultra High Molecular Weight Polyethylene (UHMWPE) has been used as a ski sole material for many years due to its good tribological properties, good wear resistance and low friction coefficient. Recent studies have showed improved performance on wear rate and hydrophobicity with nanoparticle reinforced UHMWPE. In this study, different kinds of nano-composite UHMWPE’s were tested on snow to investigate if they are suitable as a ski sole material and to find the type of nano-composite UHMWPE tha...

  1. Influence of the gap size and dielectric constant of the packing on the plasma discharge in a packed bed dielectric barrier discharge reactor: a fluid modeling study (United States)

    van Laer, Koen; Bogaerts, Annemie


    Packed bed dielectric barrier discharge (DBD) reactors have proven to be very useful sources of non-thermal plasma for a wide range of applications, of which the environmental applications have received most attention in recent years. Compared to an empty DBD reactor, a packing was introduced to either enhance the energy efficiency of the process, or, if the packing is catalytically active, steer the process towards a preferred end product. A wide range of geometries, bead sizes and bead materials have been tested experimentally in the past. However, since experimental diagnostics become more difficult with a packing present, a computational study is proposed to gain more insight. Using COMSOL's built in plasma module, a 2D axisymmetric fluid model is developed to study the influence of the gap size and the dielectric constant (ɛ) of the packing. Helium is used as discharge gas, at atmospheric pressure and room temperature. By decreasing the gas gap, the electric field strength is enhanced, resulting in a higher number of current peaks per half cycle of applied rf potential. Increasing ɛ also enhances the electric field strength. However, after a certain ɛ, its influence saturates. The electric field strength will no longer increase, leaving the discharge behavior unchanged.

  2. The hydrophobic effect: Molecular dynamics simulations of water confined between extended hydrophobic and hydrophilic surfaces

    DEFF Research Database (Denmark)

    Jensen, Morten Østergaard; Mouritsen, Ole G.; Peters, Günther H.J.


    -correlation functions reveal that water molecules have characteristic diffusive behavior and orientational ordering due to the lack of hydrogen bonding interactions with the surface. These observations suggest that the altered dynamical properties of water in contact with extended hydrophobic surfaces together...... experimental data from x-ray reflectivity measurements, reveal a uniform weak de-wetting characteristic for the extended hydrophobic surface, while the hydrophilic surface is weakly wetted. These microscopic data are consistent with macroscopic contact angle measurements. Specific water orientation is present...... at both surfaces. The ordering is characteristically different between the surfaces and of longer range at the hydrophilic surface. Furthermore, the dynamic properties of water are different at the two surfaces and different from the bulk behavior. In particular, at the hydrophobic surface, time...

  3. Transforming plastic surfaces with electrophilic backbones from hydrophobic to hydrophilic. (United States)

    Kim, Samuel; Bowen, Raffick A R; Zare, Richard N


    We demonstrate a simple nonaqueous reaction scheme for transforming the surface of plastics from hydrophobic to hydrophilic. The chemical modification is achieved by base-catalyzed trans-esterification with polyols. It is permanent, does not release contaminants, and causes no optical or mechanical distortion of the plastic. We present contact angle measurements to show successful modification of several types of plastics including poly(ethylene terephthalate) (PET) and polycarbonate (PC). Its applicability to blood analysis is explored using chemically modified PET blood collection tubes and found to be quite satisfactory. We expect this approach will reduce the cost of manufacturing plastic devices with optimized wettability and can be generalized to other types of plastic materials having an electrophilic linkage as its backbone.

  4. Salt creep and wicking counteract hydrophobic organic structures (United States)

    Burkhardt, Juergen


    The hydrophobic nature of many biological and edaphic surfaces prevents wetting and water movement. Already small amounts of salts and other hygroscopic material (e.g. by aerosol deposition to leaf surfaces) may change this situation. Salts attract minute amounts of liquid water to the surface and may dynamically expand on the original surface by creeping (evaporation-driven extension of crystals). Creeping is governed by fluctuations of relative humidity and increases with time. Under high, almost saturated concentrations of the salt solutions, ions from the chaotropic side of the Hofmeister series creep most efficiently. Once established, continuous salt connections may act to channel small water flows along the surface. They may act as wicks if water is removed from one side by evaporation. Stomata may in this way become 'leaky' by the leaf surface accumulation of hygroscopic aerosols.

  5. Separating mixtures by exploiting molecular packing effects in microporous materials

    NARCIS (Netherlands)

    Krishna, R.


    We examine mixt. sepns. with microporous adsorbents such as zeolites, metal-​org. frameworks (MOFs) and zeolitic imidazolate frameworks (ZIFs)​, operating under conditions close to pore satn. Pore satn. is realized, for example, when sepg. bulk liq. phase mixts. of polar compds. such as water, alcs.

  6. 7 CFR 319.37-9 - Approved packing material. (United States)


    ...—wood or cork. Sphagnum moss. Stockosorb superabsorbent polymer Vegetable fiber when free of pulp, including coconut fiber and Osmunda fiber, but excluding sugarcane fiber and cotton fiber. Volcanic rock...

  7. Hydrophobic binding properties of bovine gallbladder mucin. (United States)

    Smith, B F; LaMont, J T


    Hydrophobic binding properties of purified bovine gallbladder mucin were studied by fluorescence spectroscopy using 1-anilino-8-naphthalene sulfonate (ANS) and N-phenyl-1-naphthylamine. The purified glycoprotein contained 75.5%, dry weight, as carbohydrate, 16.3% as protein, and 3.7% as sulfate; Mr = 2.2 X 10(6) was estimated by chromatography on Sephacryl S-500. Mucin contained a large number of low-affinity binding sites for these hydrophobic ligands. The dissociation constant, KD of mucin-ANS binding was 2.7 X 10(-5); each mucin molecule had approximately 42 binding sites for ANS. These binding sites were deduced to be on the unglycosylated portion of the protein core, as Pronase digestion completely eliminated binding. Reduction of mucin with 2-mercaptoethanol increased the fluorescence yield by formation of subunits with increased binding sites for the ligand. Increasing NaCl concentration (0.125 to 2.0 M) and decreasing pH (9 to 3) progressively increased fluorescence with the charged ligand ANS, suggesting that the binding site may have acidic groups which are shielded at high ionic strength or low pH. The fluorescent yield with N-phenyl-1-naphthylamine, an uncharged ligand, was an order of magnitude higher than with ANS. Bilirubin and bromosulfophthalein inhibited mucin-induced ANS fluorescence, but bile acids did not. Gallbladder mucin contains hydrophobic binding domains in the nonglycosylated peptide core that are involved in polymer formation and binding of biliary lipids and pigment.

  8. Hydrophobic pocket targeting probes for enteroviruses (United States)

    Martikainen, Mari; Salorinne, Kirsi; Lahtinen, Tanja; Malola, Sami; Permi, Perttu; Häkkinen, Hannu; Marjomäki, Varpu


    Visualization and tracking of viruses without compromising their functionality is crucial in order to understand virus targeting to cells and tissues, and to understand the subsequent subcellular steps leading to virus uncoating and replication. Enteroviruses are important human pathogens causing a vast number of acute infections, and are also suggested to contribute to the development of chronic diseases like type I diabetes. Here, we demonstrate a novel method to target site-specifically the hydrophobic pocket of enteroviruses. A probe, a derivative of Pleconaril, was developed and conjugated to various labels that enabled the visualization of enteroviruses under light and electron microscopes. The probe mildly stabilized the virus particle by increasing the melting temperature by 1-3 degrees, and caused a delay in the uncoating of the virus in the cellular endosomes, but could not however inhibit the receptor binding, cellular entry or infectivity of the virus. The hydrophobic pocket binding moiety of the probe was shown to bind to echovirus 1 particle by STD and tr-NOESY NMR methods. Furthermore, binding to echovirus 1 and Coxsackievirus A9, and to a lesser extent to Coxsackie virus B3 was verified by using a gold nanocluster labeled probe by TEM analysis. Molecular modelling suggested that the probe fits the hydrophobic pockets of EV1 and CVA9, but not of CVB3 as expected, correlating well with the variations in the infectivity and stability of the virus particles. EV1 conjugated to the fluorescent dye labeled probe was efficiently internalized into the cells. The virus-fluorescent probe conjugate accumulated in the cytoplasmic endosomes and caused infection starting from 6 hours onwards. Remarkably, before and during the time of replication, the fluorescent probe was seen to leak from the virus-positive endosomes and thus separate from the capsid proteins that were left in the endosomes. These results suggest that, like the physiological hydrophobic content

  9. Responsive gelation of hydrophobized linear polymer

    DEFF Research Database (Denmark)

    Madsen, Claus Greve; Toeth, Joachim; Jørgensen, Lene

    In this study we present the rheological properties of a physically linked polymer network, composed of linear hydrophilic chains, modified with hydrophobic moieties in each end. Solutions of the polymer in ethanol-water mixtures showed Newtonian behaviour up to about 99 % ethanol, with the highe...... viscosity observed in a 1:1 mixture of ethanol and water. In pure ethanol, the polymer forms a thermo-responsive, non-Newtonian gel, which collapses upon addition of as little as 1 % water or heating to about 40 °C....

  10. 5 Reasons to Pack Your Lunch (United States)

    ... school! Here are the top 5 reasons to pack your lunch — and snacks — at least twice a week: 1. Control. Do you ever wait in the lunch line only to find when you get to the front that you don't like what they're ...

  11. Wrap-Attack Pack: Product Packaging Exercise (United States)

    Lee, Seung Hwan; Hoffman, K. Douglas


    Although many marketing courses discuss traditional concepts pertaining to product strategy, concepts specifically relating to packaging are often glossed over. This exercise, "Wrap-Attack Pack," teaches students about the utilitarian and hedonic design elements of packaging. More specifically, the primary objective is to creatively…

  12. Relationship between Malaria Parasitaemia and Packed Cell ...

    African Journals Online (AJOL)

    Malaria parasitic infection is a disease causing high morbidity and mortality in most tropical parts of the world, where climatic conditions and sanitation practices favour their prevalence. The aim of this study is to determine the prevalence of malaria parasitaemia and its influence on pack cell volume among Primary School ...

  13. Origami, Modular Packing and the Soma Puzzle

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 11. Origami, Modular Packing and the Soma Puzzle. Subramania Ranganathan. General Article Volume 8 Issue 11 November 2003 pp 71-77. Fulltext. Click here to view fulltext PDF. Permanent link:

  14. On the fractal beauty of bin packing

    NARCIS (Netherlands)

    L. Epstein (Lea); S. Seiden; R. van Stee (Rob)


    textabstractIn the variable-sized online bin packing problem, one has to assign items to bins one by one. The bins are drawn from some fixed set of sizes, and the goal is to minimize the sum of the sizes of the bins used. We present the first unbounded space algorithms for this problem. We also show

  15. Stable Aqueous Dispersions of Hydrophobically Modified Titanium Dioxide Pigments through Polyanion Adsorption: Synthesis, Characterization, and Application in Coatings. (United States)

    Jankolovits, Joseph; Kusoglu, Ahmet; Weber, Adam Z; Van Dyk, Antony; Bohling, James; Roper, John A; Radke, Clayton J; Katz, Alexander


    Polyanion dispersants stabilize aqueous dispersions of hydrophilic (native) inorganic oxide particles, including pigments currently used in paints, which are used at an annual scale of 3 million metric tons. While obtaining stable aqueous dispersions of hydrophobically modified particles has been desired for the promise of improved film performance and water barrier properties, it has until now required either prohibitively complex polyanions, which represent a departure from conventional dispersants, or multistep syntheses based on hybrid-material constructs. Here, we demonstrate the aqueous dispersion of alkylsilane-capped inorganic oxide pigments with conventional polycarboxylate dispersants, such as carboxymethylcellulose (CMC) and polyacrylate, as well as a commercial anionic copolymer. Contact-angle measurements demonstrate that the hydrophobically modified pigments retain significant hydrophobic character even after adsorbing polyanion dispersants. CMC adsorption isotherms demonstrate 92% greater polyanion loading on trimethylsilyl modified hydrophobic particles relative to native oxide at pH 8. However, consistent with prior literature, hydrophobically modified silica particles adsorb polyanions very weakly under these conditions. These data suggest that Lewis acidic heteroatoms such as Al(3+) sites on the pigment surface are necessary for polyanion adsorption. The adsorbed polyanions increase the dispersion stability and zeta potential of the particles. Based on particle sedimentation under centrifugal force, the hydrophobically modified pigments possess greater dispersion stability with polyanions than the corresponding native hydroxylated particles. The polyanions also assist in the aqueous wetting of the hydrophobic particles, facilitating the transition from a dry powder into an aqueous dispersion of primary particles using less agitation than the native hydroxylated pigment. The application of aqueous dispersions of hydrophobically modified oxide

  16. Comparison of three different polyvinyl alcohol packs following functional endoscopic Nasal surgery. (United States)

    Melis, Andrea; Karligkiotis, Apostolos; Bozzo, Corrado; Machouchas, Nikolaos; Volpi, Luca; Castiglia, Paolo; Castelnuovo, Paolo; Meloni, Francesco


    To compare the extent of bleeding and patient discomfort during packing removal of three different polyvinyl alcohol (PVA) packs: 1) a standard PVA sponge (s-PVA) (Mondocel Standard 10 cm; Mondomed NV, Hamont-Achel, Belgium); 2) a PVA sponge with oxidized cellulose (oc-PVA) (Merocel Hemox 10 cm; Medtronic Xomed Surgical Products, Jacksonville, FL); and 3) a PVA sponge with polyethylene film (pf-PVA) (Merocel 2000 8 cm; Medtronic Xomed Surgical Products, Jacksonville, FL), after functional endoscopic sinus surgery and inferior turbinoplasty. A prospective, randomized, blinded, controlled trial. Ninety consecutive patients were enrolled and randomized to receive in each side one pack in the middle meatus and another pack of the same material in the nasal fossa. The patients were equally divided in three groups of 30 patients each. Group A received the pf-PVA; group B received oc-PVA; and group C received s-PVA. Postoperatively, bleeding after removal of the entire nasal packing was evaluated by an observer, whereas the severity of pain was rated by patients with visual analog scales. Our study evaluated three nasal packing materials, demonstrating that the pf-PVA is less painful than the others but with intermediate bleeding ratio. However, the oc-PVA has an intermediate pain score but minimum bleeding. The s-PVA showed the worst pain and bleeding results. Considering that removal of the second pack (middle meatus) is more painful than the first (nasal fossa), our results suggest that a pf-PVA can be placed in the middle meatus and a oc-PVA in the nasal fossa in order to reduce patient's discomfort in terms of pain and bleeding. 1b. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

  17. Super-hydrophobic multilayer coatings with layer number tuned swapping in surface wettability and redox catalytic anti-corrosion application. (United States)

    Syed, Junaid Ali; Tang, Shaochun; Meng, Xiangkang


    The wetting characteristic of a metal surface can be controlled by employing different coating materials and external stimuli, however, layer number (n) modulated surface swapping between hydrophobicity and hydrophilicity in a multilayer structure to achieve prolonged anti-corrosion ability was not taken into consideration. In this study, we proposed a layer-by-layer (LbL) spin assembled polyaniline-silica composite/tetramethylsilane functionalized silica nanoparticles (PSC/TMS-SiO2) coating with the combined effect of super-hydrophobicity and enhanced anti-corrosion ability. Interestingly, the hierarchical integration of two coating materials with inherently different surface roughness and energy in a multilayer structure allows the wetting feature to swap from hydrophobic to hydrophilic state by modulating n with decreasing hydrophilicity. The samples with odd n (TMS-SiO2 surface) are hydrophobic while the samples with even n (PSC surface) exhibits the hydrophilic character. The TMS-SiO2 content was optimized to achieve super-hydrophobic coating with significantly high water contact angle (CA) 153° ± 2° and small sliding angle (SA) 6° ± 2°. Beside its self-cleaning behavior, the electro-active PSC/TMS-SiO2 coating also exhibits remarkably enhanced corrosion resistance against aggressive media. The corrosion resistance of the coating was remained stable even after 240 h of exposure, this enhancement is attributed to super-hydrophobicity and anodic shift in corrosion potential.

  18. Hydrophobic Sand Is a Non-Toxic Method of Urine Collection, Appropriate for Urinary Metal Analysis in the Rat (United States)

    Hoffman, Jessica F.; Vergara, Vernieda B.; Mog, Steven R.; Kalinich, John F.


    Hydrophobic sand is a relatively new method of urine collection in the rodent, comparable to the established method using a metabolic cage. Urine samples are often used in rodent research, especially for biomarkers of health changes after internal contamination from embedded metals, such as in a model of a military shrapnel wound. However, little research has been done on the potential interference of hydrophobic sand with urine metal concentrations either by contamination from the sand particulate, or adsorption of metals from the urine. We compare urine collected from rats using the metabolic cage method and the hydrophobic sand method for differences in metal concentration of common urinary metals, and examine physical properties of the sand material for potential sources of contamination. We found minimal risk of internal contamination of the rat by hydrophobic sand, and no interference of the sand with several common metals of interest (cobalt, strontium, copper, and manganese), although we advise caution in studies of aluminum in urine. PMID:29051457

  19. Non-destructive Quality control of tablets and blister packs by UV imaging

    DEFF Research Database (Denmark)

    Klukkert, Marten; Wu, Jian Xiong; Rantanen, Jukka


    Quality control of tablets and its primary packing material within the manufacturing line requires analytical routines that allow monitoring of the desired product attributes with high efficiency. The aim of this study was to evaluate the suitability of multispectral UV imaging combined with mult......Quality control of tablets and its primary packing material within the manufacturing line requires analytical routines that allow monitoring of the desired product attributes with high efficiency. The aim of this study was to evaluate the suitability of multispectral UV imaging combined...... with multivariate image analysis for verification of blister pack filling, differentiation of tablets of varying composition therein, as well as detection of imprint defects and surface cracks of bulk tablets. Moreover, the influence of polymer sealing foils on tablet characterization within blister cavities...... was investigated. Several tablets of different composition were imaged either as bulk, within unsealed blister packs, or within blister packs that were manually sealed with three different types of either PVC or PCTFE foils. It was demonstrated that UV imaging is a fast and reliable technique for counting...

  20. Structure of Hydrophobically Modified Phytoglycogen Nanoparticles (United States)

    Atkinson, John; Nickels, Jonathan; Dutcher, John; Katsaras, John

    Phytoglycogen is a highly branched, polysaccharide nanoparticle produced by some varieties of plants including sweet corn. These particles are attractive candidates for cosmetic, industrial and biomedical applications. Many of these applications result from phytoglycogen's unique interaction with water: (1) high solubility; (2) low viscosity and high stability in aqueous dispersions; and (3) a remarkable capacity to sequester and retain water. Neutron scattering measurements of native phytoglycogen revealed that the particles have uniform size, uniform radial particle density, and a high level of hydration. Hydrophobically modifying the outer surface of the hydrophilic nanoparticles opens up new applications in food and biomedicine, such as solubilizing and stabilizing bioactive compounds. One such modification is octenyl succinate anhydride (OSA), where the hydrophobicity can be tuned by adjusting the degree of substitution. I will present the results of small angle neutron scattering (SANS) measurements of aqueous dispersions of OSA-modified phytoglycogen with two different degrees of modification. Contrast series SANS measurements have yielded information about the radial density profile, providing insight into the nature of the chemical modification of the particles.

  1. Aggregate size distributions in hydrophobic flocculation

    Directory of Open Access Journals (Sweden)

    Chairoj Rattanakawin


    Full Text Available The evolution of aggregate (floc size distributions resulting from hydrophobic flocculation has been investigated using a laser light scattering technique. By measuring floc size distributions it is possible to distinguish clearly among floc formation, growth and breakage. Hydrophobic flocculation of hematite suspensions with sodium oleate under a variety of agitating conditions produces uni-modal size distributions. The size distribution of the primary particles is shifted to larger floc sizes when the dispersed suspension is coagulated by pH adjustment. By adding sodium oleate to the pre-coagulated suspension, the distribution progresses further to the larger size. However, prolonged agitation degrades the formed flocs, regressing the distribution to the smaller size. Median floc size derived from the distribution is also used as performance criterion. The median floc size increases rapidly at the initial stage of the flocculation, and decreases with the extended agitation time and intensity. Relatively weak flocs are produced which may be due to the low dosage of sodium oleate used in this flocculation study. It is suggested that further investigation should focus on optimum reagent dosage and non-polar oil addition to strengthen these weak flocs.

  2. Hydrophobic interactions of sucralose with protein structures. (United States)

    Shukla, Nimesh; Pomarico, Enrico; Hecht, Cody J S; Taylor, Erika A; Chergui, Majed; Othon, Christina M


    Sucralose is a commonly employed artificial sweetener that appears to destabilize protein native structures. This is in direct contrast to the bio-preservative nature of its natural counterpart, sucrose, which enhances the stability of biomolecules against environmental stress. We have further explored the molecular interactions of sucralose as compared to sucrose to illuminate the origin of the differences in their bio-preservative efficacy. We show that the mode of interactions of sucralose and sucrose in bulk solution differ subtly through the use of hydration dynamics measurement and computational simulation. Sucralose does not appear to disturb the native state of proteins for moderate concentrations (sucralose appears to differ in its interactions with protein leading to the reduction of native state stability. This difference in interaction appears weak. We explored the difference in the preferential exclusion model using time-resolved spectroscopic techniques and observed that both molecules appear to be effective reducers of bulk hydration dynamics. However, the chlorination of sucralose appears to slightly enhance the hydrophobicity of the molecule, which reduces the preferential exclusion of sucralose from the protein-water interface. The weak interaction of sucralose with hydrophobic pockets on the protein surface differs from the behavior of sucrose. We experimentally followed up upon the extent of this weak interaction using isothermal titration calorimetry (ITC) measurements. We propose this as a possible origin for the difference in their bio-preservative properties. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Dual Effect of (LK)nL Peptides on the Onset of Insulin Amyloid Fiber Formation at Hydrophobic Surfaces. (United States)

    Chouchane, Karim; Vendrely, Charlotte; Amari, Myriam; Moreaux, Katie; Bruckert, Franz; Weidenhaupt, Marianne


    Soluble proteins are constantly in contact with material or cellular surfaces, which can trigger their aggregation and therefore have a serious impact on the development of stable therapeutic proteins. In contact with hydrophobic material surfaces, human insulin aggregates readily into amyloid fibers. The kinetics of this aggregation can be accelerated by small peptides, forming stable beta-sheets on hydrophobic surfaces. Using a series of (LK)nL peptides with varying length, we show that these peptides, at low, substoichiometric concentrations, have a positive, cooperative effect on insulin aggregation. This effect is based on a cooperative adsorption of (LK)nL peptides at hydrophobic surfaces, where they form complexes that help the formation of aggregation nuclei. At higher concentrations, they interfere with the formation of an aggregative nucleus. These effects are strictly dependent on the their adsorption on hydrophobic material surfaces and highlight the importance of the impact of materials on protein stability. (LK)nL peptides prove to be valuable tools to investigate the mechanism of HI aggregation nuclei formation on hydrophobic surfaces.

  4. Modified strip packing heuristics for the rectangular variable-sized bin packing problem

    Directory of Open Access Journals (Sweden)

    FG Ortmann


    Full Text Available Two packing problems are considered in this paper, namely the well-known strip packing problem (SPP and the variable-sized bin packing problem (VSBPP. A total of 252 strip packing heuristics (and variations thereof from the literature, as well as novel heuristics proposed by the authors, are compared statistically by means of 1170 SPP benchmark instances in order to identify the best heuristics in various classes. A combination of new heuristics with a new sorting method yields the best results. These heuristics are combined with a previous heuristic for the VSBPP by the authors to find good feasible solutions to 1357 VSBPP benchmark instances. This is the largest statistical comparison of algorithms for the SPP and the VSBPP to the best knowledge of the authors.

  5. Hydrophobic amino acids grafted onto chitosan: a novel amphiphilic chitosan nanocarrier for hydrophobic drugs. (United States)

    Motiei, Marjan; Kashanian, Soheila; Taherpour, Avat Arman


    The objective of this study is to develop a novel biocompatible amphiphilic drug delivery for hydrophobic drugs, chitosan (CS) was grafted to a series of hydrophobic amino acids including l-alanine (A), l-proline (P), and l-tryptophan (W) by carbodiimide mediated coupling reaction. Chemical characteristics of the modified polymers were determined and confirmed by FT-IR, (1)H NMR, and UV-vis spectroscopy and the degree of substitution was quantified by elemental analysis. The modified polymers were used to form amphiphilic chitosan nanocarriers (ACNs) by the conventional self-assembly method using ultrasound technique. The morphology and the size of ACNs were analyzed by scanning electron microscope (SEM) and Dynamic light scattering (DLS). The sizes of spherical ACNs analyzed by SEM were obviously smaller than those of determined by DLS. The ACNs effectively surrounded the hydrophobic model drug, letrozole (LTZ), and demonstrated different encapsulation efficiencies (EE), loading capacities (LC), and controlled drug release profiles. The characteristics of ACNs and the mechanism of drug encapsulation were confirmed by molecular modeling method. The modeling of the structures of LTZ, profiles of A, P, and W grafted onto CS and the wrapping process around LTZ was performed by quantum mechanics (QM) methods. There was a good agreement between the experimental and theoretical results. The cell viability was also evaluated in two cell lines compared with free drug by MTT assay. The hydrophobic portion effects on ACNs' characteristics and the proper selection of amino acid demonstrate a promising potential for drug delivery vector.

  6. Column-to-column packing variation of disposable pre-packed columns for protein chromatography. (United States)

    Schweiger, Susanne; Hinterberger, Stephan; Jungbauer, Alois


    In the biopharmaceutical industry, pre-packed columns are the standard for process development, but they must be qualified before use in experimental studies to confirm the required performance of the packed bed. Column qualification is commonly done by pulse response experiments and depends highly on the experimental testing conditions. Additionally, the peak analysis method, the variation in the 3D packing structure of the bed, and the measurement precision of the workstation influence the outcome of qualification runs. While a full body of literature on these factors is available for HPLC columns, no comparable studies exist for preparative columns for protein chromatography. We quantified the influence of these parameters for commercially available pre-packed and self-packed columns of disposable and non-disposable design. Pulse response experiments were performed on 105 preparative chromatography columns with volumes of 0.2-20ml. The analyte acetone was studied at six different superficial velocities (30, 60, 100, 150, 250 and 500cm/h). The column-to-column packing variation between disposable pre-packed columns of different diameter-length combinations varied by 10-15%, which was acceptable for the intended use. The column-to-column variation cannot be explained by the packing density, but is interpreted as a difference in particle arrangement in the column. Since it was possible to determine differences in the column-to-column performance, we concluded that the columns were well-packed. The measurement precision of the chromatography workstation was independent of the column volume and was in a range of±0.01ml for the first peak moment and±0.007 ml 2 for the second moment. The measurement precision must be considered for small columns in the range of 2ml or less. The efficiency of disposable pre-packed columns was equal or better than that of self-packed columns. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  7. Nanoscale physicochemical properties of chain- and step-growth polymerized PEG hydrogels affect cell-material interactions. (United States)

    Vats, Kanika; Marsh, Graham; Harding, Kristen; Zampetakis, Ioannis; Waugh, Richard E; Benoit, Danielle S W


    Poly(ethylene glycol) (PEG) hydrogels provide a versatile platform to develop cell instructive materials through incorporation of a variety of cell adhesive ligands and degradable chemistries. Synthesis of PEG gels can be accomplished via two mechanisms: chain and step growth polymerizations. The mechanism dramatically impacts hydrogel nanostructure, whereby chain polymerized hydrogels are highly heterogeneous and step growth networks exhibit more uniform structures. Underpinning these alterations in nanostructure of chain polymerized hydrogels are densely-packed hydrophobic poly(methyl methacrylate) or poly(acrylate) kinetic chains between hydrophilic PEG crosslinkers. As cell-material interactions, such as those mediated by integrins, occur at the nanoscale and affect cell behavior, it is important to understand how different modes of polymerization translate into nanoscale mechanical and hydrophobic heterogeneities of hydrogels. Therefore, chain- and step-growth polymerized PEG hydrogels with macroscopically similar macromers and compliance (for example, methacrylate-functionalized PEG (PEGDM), MW  = 10 kDa and norbornene-functionalized 4-arm PEG (PEGnorb), MW  = 10 kDa) were used to examine potential nanoscale differences in hydrogel mechanics and hydrophobicity using atomic force microscopy (AFM). It was found that chain-growth polymerized network yielded greater heterogeneities in both stiffness and hydrophobicity as compared to step-growth polymerized networks. These nanoscale heterogeneities impact cell-material interactions, particularly human mesenchymal stem cell (hMSC) adhesion and spreading, which has implications in use of these hydrogels for tissue engineering applications. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1112-1122, 2017. © 2017 Wiley Periodicals, Inc.

  8. Modelling of Packed Co Nanorods for Hard Magnetic Applications

    Directory of Open Access Journals (Sweden)

    Toson P.


    Full Text Available We present a numerical algorithm based on the bullet physics library to generate densely packed (39% - 41% structures of high-aspect-ratio nanorods for finite element micromagnetic simulations. The coercivities µ0Hc of the corresponding Cobalt nanorod structures vary between 0.50T and 0.67T, depending on the overall orientation of nanorods, which is in good agreement with experimental results. The simulations make it possible to estimate the coercivity loss due to incoherent reversal processes (27% as well as the gain due to shape anisotropy (59%. Our calculations show permanent magnets consisting of packed Co nanorods with an energy density product (BHmax of 83kJ/m3. We estimate that this value can be increased to 103kJ/m3 by increasing the packing density from 40% to 45%. Another way to optimize (BHmax is the usage of novel materials. By varying the anisotropy constant K1 and the saturation polarisation JS we found lower limits for these parameters to reach a certain energy density product. To increase (BHmax to 160 kJ/m3, K1 and JS have to be in the order of 450kJ/m3 and 2.25T, respectively. The thermal stability of this approach was verified by elastic band calculations. Cobalt nanorods with a diameter of 10nm and a height of 50nm are thermally stable at room temperature, but problematic at 900K. Doubling the nanorods' height to 100nm increases that limit considerably.

  9. Performance specifications for pack support types to cater for the variety of geotechnical areas encountered in the mining industry.

    CSIR Research Space (South Africa)

    Kullmann, D


    Full Text Available characteristics, pack construction and manufacturing quality. 3.1 Timber characteristics Timber is a natural material which can only be partly managed by foresters and nurserymen to improve its most desirable characteristics. There are a number of natural... frequently used for product development and routine testing. This press is sufficiently large to test any pack and has a piston stroke in excess of 400 mm. The platens can also be reset during a test to conduct a second compression on the pack for another...

  10. LondonMet e-Packs: A Pragmatic Approach to Learner/Teacher Autonomy (United States)

    Tschirhart, Cecile; Rigler, Elina


    Online learning can play an important role in engaging language learners and fostering autonomy. The LondonMet e-pack, which provides online interactive language learning materials, is used as a case study to illustrate some of the theoretical and practical issues faced by those implementing online language learning programmes. This article begins…

  11. Catalytic Pyrolysis of Oak via Pyroprobe and Bench Scale, Packed Bed Pyrolysis Reactors (United States)

    The pyrolytic conversion of oak sawdust at 500°C in flowing He over eight proprietary catalysts is described and compared to the control bed material, quartz sand. The reactions were conducted and compared in two reactors, an analytical, ug-scale pyroprobe reactor and a bench, g-scale packed bed re...

  12. Non-destructive Quality control of tablets and blister packs by UV imaging

    DEFF Research Database (Denmark)

    Klukkert, Marten; Wu, Jian Xiong; Rantanen, Jukka


    Quality control of tablets and its primary packing material within the manufacturing line requires analytical routines that allow monitoring of the desired product attributes with high efficiency. The aim of this study was to evaluate the suitability of multispectral UV imaging combined with mult...

  13. Subcutaneous packing in royal Egyptian mummies dated from 18th to 20th dynasties. (United States)

    Saleem, Sahar N; Hawass, Zahi


    It has been widely disseminated in the literature that subcutaneous packing, as part of mummification, was not usually done until the 21st dynasty. We aimed to study by computed tomography (CT) if subcutaneous packing was part of mummification of royal Egyptians dated to 18th to 20th dynasties. We analyzed the 2- and 3-dimensional CT images of 13 royal mummies dated to circa 1550 to 1153 BC for presence of subcutaneous embalming materials. Among the studied mummies were Amenhotep III, Tutankhamun, Seti I, and Ramesses II. We reported the CT characters of any detected subcutaneous embalming materials and noted their impact on the morphology of the involved body part. We correlated the CT findings with the archeological literature. Computed tomographic images showed subcutaneous packing in 12 (92.3%) mummies; whereas the mummy that was previously known as "Thutmose I" showed no such evidence. Subcutaneous packing involved the faces (n = 11), necks (n = 4), torsos (n = 5), and/or extremities (n = 4) of the mummies. Subcutaneous filling materials showed variation in homogeneity and CT densities and they were likely composed of resin, bits of linen with resin, or other substances. Subcutaneous packing procedure succeeded in providing uniform full contour of the involved body regions without causing significant tissue damages. Subcutaneous packing procedure was used as part of mummification of royal Ancient Egyptians dated to 18th to 20th dynasties earlier than what was believed in archaeology. The Ancient Egyptian embalmers must have been skilled in dissection and possessed surgical tools that enabled them to perform this fine procedure.

  14. High efficiency and fast separation of active proteins by HIC chromatographic pie with sub-2 μm polymer packings. (United States)

    Ke, Cong-Yu; Lu, Guo-Min; Sun, Wu-Juan; Zhang, Xun-Li


    This paper reports the development of hydrophobic interaction chromatography (HIC) by synthesizing sub-2 μm polymer packings which was packed into a chromatographic pie for fast separation of native proteins at low pressures demonstrating high efficiency. Using styrene as monomer and ethylene dimethacrylate (EDMA)as swelling agent, the polystyrene seeds with an average particle size of 0.8 μm and monodisperse polymeric microspheres with a particle size of 1.5-5.0 μm were synthesized through dispersion polymerization and one-step swelling method, respectively. In order to separate active proteins, the microspheres were modified to hydrophobic chromatographic packings through covalent bonding with benzene methanol. Compared with the traditional column chromatography, the sub-2 μm polymer packings in chromatographic pie exhibited higher column efficiency for protein separation at lower column pressures, even at higher flow rates. The van Deemter curve showed that the flow rate had insignificant effect on column efficiency of chromatographic pie. Seven example proteins were clearly separated within 3 min at a flow rate of 10 mL/min. The applicability of this method was further demonstrated by the separation of human serum samples. The results indicated that this chromatographic mode can be potentially applied for the fast separation of complex active proteins, such as protein drugs from natural products. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Spider Silk Violin Strings with a Unique Packing Structure Generate a Soft and Profound Timbre (United States)

    Osaki, Shigeyoshi


    We overcome the difficulties in pulling long draglines from spiders, twist bundles of dragline filaments, and succeed in preparing violin strings. The twisting is found to change the cross section shapes of filaments from circular to polygonal and to optimize the packing structure with no openings among filaments providing mechanically strong and elastic strings. The spider string signal peaks of overtones for the violin are relatively large at high frequencies, generating a soft and profound timbre. Such a preferable timbre is considered to be due to the unique polygonal packing structure which provides valuable knowledge for developing new types of materials.

  16. Computational Protein Design with Explicit Consideration of Surface Hydrophobic Patches (United States)

    Jacak, Ron; Leaver-Fay, Andrew; Kuhlman, Brian


    De novo protein design requires the identification of amino-acid sequences that favor the target folded conformation and are soluble in water. One strategy for promoting solubility is to disallow hydrophobic residues on the protein surface during design. However, naturally occurring proteins often have hydrophobic amino acids on their surface that contribute to protein stability via the partial burial of hydrophobic surface area or play a key role in the formation of protein-protein interactions. A less restrictive approach for surface design that is used by the modeling program Rosetta is to parameterize the energy function so that the number of hydrophobic amino acids designed on the protein surface is similar to what is observed in naturally occurring monomeric proteins. Previous studies with Rosetta have shown that this limits surface hydrophobics to the naturally occurring frequency (~28%) but that it does not prevent the formation of hydrophobic patches that are considerably larger than those observed in naturally occurring proteins. Here, we describe a new score term that explicitly detects and penalizes the formation of hydrophobic patches during computational protein design. With the new term we are able to design protein surfaces that include hydrophobic amino acids at naturally occurring frequencies, but do not have large hydrophobic patches. By adjusting the strength of the new score term the emphasis of surface redesigns can be switched between maintaining solubility and maximizing folding free energy. PMID:22223219

  17. Thermally stable hydrophobicity in electrospun silica/polydimethylsiloxane hybrid fibers (United States)

    Wei, Zhonglin; Li, Jianjun; Wang, Chao; Cao, Jungang; Yao, Yongtao; Lu, Haibao; Li, Yibin; He, Xiaodong


    In order to improve practical performances of silica-based inorganic/organic hybrid fibers, silica/polydimethylsiloxane hydrophobic fibers were successfully prepared by electrospinning. Silica sol and polydimethylsiloxane can be mixed homogeneously and become stable precursor solution in dichloromethane, which allows the transformation of silica/polydimethylsiloxane precursor solution into ultrafine fibers. Flame can ignite organic groups in polydimethylsiloxane directly and destroy the hydrophobicity of hybrid fibers, but hydrophobic feature may survive if electrospun hybrid membrane is combined with thin stainless-steel-304 gauze of 150 meshes due to its thermally stable hydrophobicity (>600 °C).

  18. Is incest common in gray wolf packs? (United States)

    Smith, Deborah E; Meier, Thomas J.; Geffen, Eli; Mech, L. David; Burch, John W.; Adams, Layne G.; Wayne, Robert K.


    Wolf packs generally consist of a breeding pair and their maturing offspring that help provision and protect pack young. Because the reproductive tenure in wolves is often short, reproductively mature offspring might replace their parents, resulting in sibling or parent-offspring matings. To determine the extent of incestuous pairings, we measured relatedness based on variability in 20 microsatellite loci of mated pairs, parent-offspring pairs, and siblings in two populations of gray wolves. Our 16 sampled mated pairs had values of relatedness not overlapping those of known parent-offspring or sibling dyads, which is consistent with their being unrelated or distantly related. These results suggest that full siblings or a parent and its offspring rarely mate and that incest avoidance is an important constraint on gray wolf behavioral ecology.

  19. Imaging of drug smuggling by body packing. (United States)

    Sica, Giacomo; Guida, Franco; Bocchini, Giorgio; Iaselli, Francesco; Iadevito, Isabella; Scaglione, Mariano


    Body packing, pushing, and stuffing are hazardous practices with complex medicolegal and social implications. A radiologist plays both a social and a medicolegal role in their assessment, and it should not be limited only to the identification of the packages but must also provide accurate information about their number and their exact location so as to prevent any package remains in the body packer. Radiologists must also be able to recognize the complications associated with these risky practices. Imaging assessment of body packing is performed essentially through plain abdominal X-ray and computed tomography scans. Ultrasound and magnetic resonance imaging, although with some advantages, actually have a limited use. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Body Packing: From Seizures to Laparotomy

    Directory of Open Access Journals (Sweden)

    Joanna M. Janczak


    Full Text Available Body packing is a common method for illegal drug trafficking. Complications associated with body packing can be severe and even lead to rapid death. Thus, a timely diagnosis is warranted. As most body packers initially do not show any symptoms, making a correct diagnosis can be rather challenging. We describe a case of a 41-year-old male, who was admitted with an epileptic seizure and who turned out to be a cocaine intoxicated body packer. Due to neurological and cardiovascular deterioration an emergency surgery was performed. Four bags of cocaine could be removed. We discuss the current management regimen in symptomatic and asymptomatic body packers and highlight pearls and pitfalls with diagnosis and treatment.

  1. Particle packing of cement and silica fume in pastes using an analytical model

    Directory of Open Access Journals (Sweden)


    Full Text Available When added to concrete in appropriate content, silica fume may provide an increase in the mechanical strength of the material due to its high pozzolanic reactivity. In addition to the chemical contribution, physical changes can also be observed in concretes with silica fume due to an improvement in the particle packing of the paste. This is a result of their small size spherical particles, which fill the voids between the larger cement grains. However, it is necessary to properly establish the cement replacement content by silica fume, because at high amounts, which exceed the volume of voids between the cement particles, silica fume can promote the loosening of these particles. Thus, instead of filling the voids and increasing the packing density, the addition of silica fume will increase the volume of voids, decreasing the solid concentration. Consequently, this will impair the properties of the concrete. The objective of this paper is to use a particle packing analytical model, the CPM (Compressible Packing Model, to verify the maximum packing density of cement and silica fume, which could be associated with the silica fume optimum content in pastes. The ideal content of silica fume in pastes, mortars and concretes is usually experimentally determined. However, a theoretical study to contrast experimental data may help understanding the behaviour of silica fume in mixes. Theoretical results show maximum amounts of silica fume in the order of 18 to 20% of the cement weight, which is high considering recommendations on literature of 15%. Nevertheless, the packing model does not consider the effect of silica fume high specific surface on the agglomeration of particles or water demand. Hence, the packing density predicted by this model cannot be used as the single parameter in determining the optimum amount of silica fume in pastes.

  2. 36 CFR 1002.16 - Horses and pack animals. (United States)


    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Horses and pack animals. 1002... AND RECREATION § 1002.16 Horses and pack animals. The following are prohibited: (a) The use of animals other than those designated as “pack animals” for purposes of transporting equipment. (b) The use of...

  3. 36 CFR 34.10 - Saddle and pack animals. (United States)


    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Saddle and pack animals. 34... INTERIOR EL PORTAL ADMINISTRATIVE SITE REGULATIONS § 34.10 Saddle and pack animals. The use of saddle and pack animals is prohibited without a permit from the Superintendent. ...

  4. 36 CFR 2.16 - Horses and pack animals. (United States)


    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Horses and pack animals. 2.16... RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.16 Horses and pack animals. The following are prohibited: (a) The use of animals other than those designated as “pack animals” for purposes of transporting...

  5. Pack nitriding of aluminium using cassava waste | Shitta | Journal of ...

    African Journals Online (AJOL)

    Pack Nitriding is a process analogous to pack carbonizing. In this work, cassava leaves were employed as a source of nitrogen. Upon heating, slow decomposition of the compound provides Nitrogen, the Nitrogen was allowed to interact with aluminium metal surfaces, which were packed nitrided at temperature of 350°c.

  6. New Structured Packing CUB for Purification of Exhaust Gases

    Directory of Open Access Journals (Sweden)

    Irina Novikova


    Full Text Available New structured packing for heat and mass transfer processes named CUB is presented in our article. The packing can be applied in packed towers for exhaust gas cleaning instead random packing, for example, rings type that are the most used in such processes. The advantages of the new packing over random packing are lower pressure drop, capability of purification and as a consequence long-term service of the packing. The researches of intensity of liquid-phase mass-transfer in packed bed depending on liquid spray rate and gas velocity were carried out. Obtained data show that packing CUB is more effective than the most popular type of structured packing under all other conditions being equal. As experimental data shown heat transfer coefficient was up by 17% and mass transfer coefficient was up by 51%. We found out optimal geometry of cross section of the new packing, namely, number of elements and parameters of one element. The new construction of structured packing is applicable for both type of column cross-section round and square.

  7. Modified strip packing heuristics for the rectangular variable-sized ...

    African Journals Online (AJOL)

    Frank G Ortmann

    Key words: Packing problems, heuristics. 1 Introduction. While cutting and packing (C&P) problems have been studied for many years, e.g. the packing of animals, seafaring vessel, trains and vehicles, these problems have only become an active field of mathematical study since the 1939 landmark paper by Kantorovich [47].

  8. 27 CFR 24.255 - Bottling or packing wine. (United States)


    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Bottling or packing wine..., DEPARTMENT OF THE TREASURY LIQUORS WINE Storage, Treatment and Finishing of Wine Bottling, Packing, and Labeling of Wine § 24.255 Bottling or packing wine. (a) General. Proprietors of a bonded wine premises and...

  9. Comparison of Microleakage and Penetration Depth between Hydrophilic and Hydrophobic Sealants in Primary Second Molar. (United States)

    Gawali, Pritesh N; Chaugule, Vishwas B; Panse, Amey M


    Optimal pit and fissure sealing is determined by surface preparation techniques and choice of materials. The performance of pit and fissure sealant materials has been intensively investigated, yet no single product is reported as an ideal sealant. In children, moisture control during cavity preparation is always a big challenge, and hence, hydrophilic sealants have been developed. To compare the microleakage and penetration depth of hydrophilic and hydrophobic sealants using acid-etching on dry and moist surfaces. Recently, extracted 28 2nd primary molars are assigned to two groups (hydrophobic group I; hydrophilic group II) depending on the surface condition (dry group: A1 and B1; moist group: A2 and B2) of 7 teeth in each group. Samples from group A1 and B1 are cleaned and dried with a 3-way syringe and etched with etching gel, and sealant is applied to the fissures and cured with visible light. Sample from A2 and B2 are immersed in 0.1 mL of fresh whole human saliva for 20 seconds and dried using a pellet cotton, and the same procedure is carried out. All samples are subjected to 1000 thermal cycles and sectioned to compare the depth of penetration and microleakage. Sections will be examined under light microscope and analyzed using an image analysis software (SigmaScan). The least microleakage was seen with hydrophilic sealant under moist surface condition, and the depth of penetration of hydrophobic sealant was found to be better than that of hydrophilic sealant in both dry and moist surface conditions. Hydrophilic pit and fissure sealants showed higher tolerance to saliva contamination with less microleakage, but in terms of penetration ability hydrophobic sealants were found to be superior. Gawali PN, Chaugule VB, Panse AM. Comparison of Microleakage and Penetration Depth between Hydrophilic and Hydrophobic Sealants in Primary Second Molar. Int J Clin Pediatr Dent 2016;9(4):291-295.

  10. Spatial distribution and packing of xylem conduits. (United States)

    Martínez-Vilalta, Jordi; Mencuccini, Maurizio; Alvarez, Xavier; Camacho, Juan; Loepfe, Lasse; Piñol, Josep


    The hydraulic properties of the xylem determine the ability of plants to transport water from the soil to the leaves and to cope with important stress factors such as frost and drought. Hydraulic properties have usually been studied as a function of the anatomy of xylem conduits and their pits, but recent studies have proposed that system-level properties, related to the topology of the xylem network, may also play a role. Here we study how the spatial arrangement of conduits in xylem cross sections affects the relationship between mean conduit lumen area and conduit density (packing function) across species. Point pattern analysis was used to describe the spatial distribution of xylem conduits in 97 woody species. The effect of conduit aggregation on the packing function was tested using phylogenetic generalized least squares. A hydraulic model with an explicit description of the topology of the xylem network was used to interpret the functional significance of our findings. The spatial arrangement of conduits affected the packing function across species, so that species with aggregated distributions tended to have lower conduit densities for a given conduit size and lower conduit lumen fractions. According to our modeling results, the higher conduit-to-conduit connectivity of species with aggregated distributions allows them to achieve higher hydraulic conductivity. Species with aggregated conduits, however, pay a cost in terms of increased vulnerability to embolism. The spatial arrangement of conduits affects the fundamental structural and functional attributes of the xylem.

  11. Dynamics of water trapped between hydrophobic solutes. (United States)

    Choudhury, Niharendu; Pettitt, B Montgomery


    We describe the model dynamical behavior of the solvent between two nanoscopic hydrophobic solutes. The dynamics of the vicinal water in various sized traps is found to be significantly different from bulk behavior. We consider the dynamics at normal temperature and pressure at three intersolute distances corresponding to the three solvent separated minima in the free energy profile between the solutes with attractions. These three states correspond to one, two, and three intervening layers of water molecules. Results are obtained from a molecular dynamics simulation at constant temperature and pressure (NPT) ensemble. Translational diffusion of water molecules trapped between the two solutes has been analyzed from the velocity correlation function as well as from the mean square displacement of the water molecules. The rotational behavior has been analyzed through the reorientational dynamics of the dipole moment vector of the water molecule by calculating both first and second rank dipole-dipole correlation functions. Both the translational and reorientational mobilities of water are found to be much slower at the smaller separation and increases as the separation between solutes becomes larger. The occupation time distribution functions calculated from the trajectories also show that the relaxation is much slower for the smallest intersolute separation as compared to other wider separations. The sublinear trend in mean square displacement and the stretched exponential decay of the relaxation of dipolar correlation and occupation distribution function indicate that the dynamical behavior of water in the confined region between two large hydrophobic solutes departs from usual Brownian behavior. This behavior is reminiscent of the behavior of water in the vicinity of protein surface clefts or trapped between two domains of a protein.

  12. Determination of Hydrophobic Contact Angle of Epoxy Resin Compound Silicon Rubber and Silica (United States)

    Syakur, Abdul; Hermawan; Sutanto, Heri


    Epoxy resin is a thermosetting polymeric material which is very good for application of high voltage outdoor insulator in electrical power system. This material has several advantages, i.e. high dielectric strength, light weight, high mechanical strength, easy to blend with additive, and easy maintenance if compared to that of porcelain and glass outdoor insulators which are commonly used. However, this material also has several disadvantages, i.e. hydrophilic property, very sensitive to aging and easily degraded when there is a flow of contaminants on its surface. The research towards improving the performance of epoxy resin insulation materials were carried out to obtain epoxy resin insulating material with high water repellent properties and high surface tracking to aging. In this work, insulating material was made at room temperature vulcanization, with material composition: Diglycidyl Ether Bisphenol A (DGEBA), Metaphenylene Diamine (MPDA) as hardener with stoichiometric value of unity, and nanosilica mixed with Silicon Rubber (SiR) with 10% (RTV21), 20% (RTV22), 30% (RTV23), 40% (RTV24) and 50% (RTV25) variation. The usage of nanosilica and Silicon Rubber (SIR) as filler was expected to provide hydrophobic properties and was able to increase the value of surface tracking of materials. The performance of the insulator observed were contact angle of hydrophobic surface materials. Tests carried out using Inclined Plane Tracking procedure according to IEC 60-587: 1984 with Ammonium Chloride (NH4Cl) as contaminants flowed using peristaltic pumps. The results show that hydrophobic contact angle can be determined from each sample, and RTV25 has maximum contact angle among others.

  13. Influence of structured packing on gas holdup in a three-phase bubble column

    DEFF Research Database (Denmark)

    Monsalvo, Matias Alfonso; Böhm, Ursula


    . The influence of structured packing on the total gas holdup for different superficial gas velocities was found to be similar with and without suspended solids. Therefore, the results obtained in this work were analysed on the basis of correlations derived earlier for gas-liquid dispersions. Excepting......In this work, the influence of structured packing on gas holdup in gas-liquid-solid dispersions has been studied. The experiments were carried out in an empty column and in column containing structured packing operating under identical conditions. Glass beads and silicon carbide particles were used...... as the solid material and the volumetric fraction of solids was varied from 0% to around 10%. The liquid viscosity was strongly modified using water, CMC solution and glycerol. The experimental results obtained with both columns were compared with previous results obtained in two-phase bubble columns...

  14. Simulation of the Carton Erection for the Rubber Glove Packing Machine Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Jewsuwun Kawin


    Full Text Available The rubber glove packing machine had been designed an important function which worked with folding carton. Each folded paper carton would be pulled to be erected by vacuum cups. Some carton could not completely form because of an unsuitable design of the erector. Cartons were collapsed or buckling while pulled by vacuum cups that cause to sudden stop the packing process and affect to number and cost of rubber glove production. This research aimed to use simulation method to erect the folded carton. Finite element (FE model of the rubber glove carton was created with shell elements. The orthotropic material properties were employed to specify FE model for analysis erection behavior of the folding carton. Vacuum cups number, positions and rotation points were simulated until obtained a good situation of the folding carton erector. Subsequently, finite element analysis results will be used to fabricate erector of the rubber glove packing machine in a further work.

  15. Conversion of NO with a catalytic packed-bed dielectric barrier discharge reactor (United States)

    Xu, CAO; Weixuan, ZHAO; Renxi, ZHANG; Huiqi, HOU; Shanping, CHEN; Ruina, ZHANG


    This paper discusses the conversion of nitric oxide (NO) with a low-temperature plasma induced by a catalytic packed-bed dielectric barrier discharge (DBD) reactor. Alumina oxide (Al2O3), glass (SiO2) and zirconium oxide (ZrO2), three different spherical packed materials of the same size, were each present in the DBD reactor. The NO conversion under varying input voltage and specific energy density, and the effects of catalysts (titanium dioxide (TiO2) and manganese oxide (MnO x ) coated on Al2O3) on NO conversion were investigated. The experimental results showed that NO conversion was greatly enhanced in the presence of packed materials in the reactor, and the catalytic packed bed of MnO x /Al2O3 showed better performance than that of TiO2/Al2O3. The surface and crystal structures of the materials and catalysts were characterized through scanning electron microscopy analysis. The final products were clearly observed by a Fourier transform infrared spectrometer and provided a better understanding of NO conversion.

  16. X-ray computed tomography of packed bed chromatography columns for three dimensional imaging and analysis. (United States)

    Johnson, T F; Levison, P R; Shearing, P R; Bracewell, D G


    Physical characteristics critical to chromatography including geometric porosity and tortuosity within the packed column were analysed based upon three dimensional reconstructions of bed structure in-situ. Image acquisition was performed using two X-ray computed tomography systems, with optimisation of column imaging performed for each sample in order to produce three dimensional representations of packed beds at 3μm resolution. Two bead materials, cellulose and ceramic, were studied using the same optimisation strategy but resulted in differing parameters required for X-ray computed tomography image generation. After image reconstruction and processing into a digital three dimensional format, physical characteristics of each packed bed were analysed, including geometric porosity, tortuosity, surface area to volume ratio as well as inter-bead void diameters. Average porosities of 34.0% and 36.1% were found for ceramic and cellulose samples and average tortuosity readings at 1.40 and 1.79 respectively, with greater porosity and reduced tortuosity overall values at the centre compared to the column edges found in each case. X-ray computed tomography is demonstrated to be a viable method for three dimensional imaging of packed bed chromatography systems, enabling geometry based analysis of column axial and radial heterogeneity that is not feasible using traditional techniques for packing quality which provide an ensemble measure. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  17. Electropolymerized conjugated polyelectrolytes with tunable work function and hydrophobicity as an anode buffer in organic optoelectronics. (United States)

    Lacher, Sebastian; Obata, Naoki; Luo, Shyh-Chyang; Matsuo, Yutaka; Zhu, Bo; Yu, Hsiao-hua; Nakamura, Eiichi


    A new class of conductive polyelectrolyte films with tunable work function and hydrophobicity has been developed for the anode buffer layer in organic electronic devices. The work function of these films featuring a copolymer of ethylenedioxythiophene (EDOT), and its functionalized analogues were found to be easily tunable over a range of almost 1 eV and reach values as high as those of PEDOT:PSS. The new buffer material does not need the addition of any insulating or acidic material that might limit the film conductivity or device lifetime. Organic photovoltaic devices built with these films showed improved open-circuit voltage over those of the known PSS-free conductive EDOT-based polymers with values as high as that obtained for PEDOT:PSS. Furthermore, the surface hydrophobicity of these new copolymer films was found to be sensitive to the chemical groups attached to the polymer backbone, offering an attractive method for surface energy tuning.

  18. Low-Ceiling-Temperature Polymer Microcapsules with Hydrophobic Payloads via Rapid Emulsion-Solvent Evaporation. (United States)

    Tang, Shijia; Yourdkhani, Mostafa; Possanza Casey, Catherine M; Sottos, Nancy R; White, Scott R; Moore, Jeffrey S


    We report a microencapsulation procedure based on rapid solvent evaporation to prepare microcapsules with hydrophobic core materials and low-ceiling-temperature polymer shell wall of cyclic poly(phthalaldehyde) (cPPA). We use and compare microfluidic and bulk emulsions. In both methods, rapid solvent evaporation following emulsification resulted in kinetically trapped core-shell microcapsules, whereas slow evaporation resulted in acorn morphology. Through the systematic variation of encapsulation parameters, we found that polymer-to-core weight ratios higher than 1 and polymer concentrations higher than 4.5 wt % in the oil phase were required to obtain a core-shell structure. This microencapsulation procedure enabled the fabrication of microcapsules with high core loading, controlled size, morphology, and stability. This procedure is versatile, allowing for the encapsulation of other hydrophobic core materials, i.e., mineral oil and organotin catalyst, or using an alternative low-ceiling-temperature polymer shell wall, poly(vinyl tert-butyl carbonate sulfone).

  19. HETP evaluation of structured packing distillation column

    Directory of Open Access Journals (Sweden)

    A. E. Orlando Jr.


    Full Text Available Several tests with a hydrocarbon mixture of known composition (C8-C14, obtained from DETEN Chemistry S.A., have been performed in a laboratory distillation column, having 40mm of nominal diameter and 2.2m high, with internals of Sulzer DX gauze stainless steel structured packing. The main purpose of this work was to evaluate HETP of a structured packing laboratory scale distillation column, operating continuously. Six HETP correlations available in the literature were compared in order to find out which is the most appropriate for structured packing columns working with medium distillates. Prior to the experimental tests, simulation studies using commercial software PRO/II® were performed in order to establish the optimum operational conditions for the distillation, especially concerning operating pressure, top and bottom temperatures, feed location and reflux ratio. The results of PRO/II® were very similar to the analysis of the products obtained during continuous operation, therefore permitting the use of the properties calculated by that software on the theoretical models investigated. The theoretical models chosen for HETP evaluation were: Bravo, Rocha and Fair (1985; Rocha, Bravo and Fair (1993, 1996; Brunazzi and Pagliant (1997; Carlo, Olujić and Pagliant (2006; Olujić et al., (2004. Modifications concerning calculation of specific areas were performed on the correlations in order to fit them for gauze packing HETP evaluation. As the laboratory distillation column was operated continuously, different HETP values were found by the models investigated for each section of the column. The low liquid flow rates in the top section of the column are a source of error for HETP evaluation by the models; therefore, more reliable HETP values were found in the bottom section, in which liquid flow rates were much greater. Among the theoretical models, Olujić et al. (2004 has shown good results relative to the experimental tests. In addition, the

  20. Super-Hydrophobic/Icephobic Coatings Based on Silica Nanoparticles Modified by Self-Assembled Monolayers

    Directory of Open Access Journals (Sweden)

    Junpeng Liu


    Full Text Available A super-hydrophobic surface has been obtained from nanocomposite materials based on silica nanoparticles and self-assembled monolayers of 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS using spin coating and chemical vapor deposition methods. Scanning electron microscope images reveal the porous structure of the silica nanoparticles, which can trap small-scale air pockets. An average water contact angle of 163° and bouncing off of incoming water droplets suggest that a super-hydrophobic surface has been obtained based on the silica nanoparticles and POTS coating. The monitored water droplet icing test results show that icing is significantly delayed by silica-based nano-coatings compared with bare substrates and commercial icephobic products. Ice adhesion test results show that the ice adhesion strength is reduced remarkably by silica-based nano-coatings. The bouncing phenomenon of water droplets, the icing delay performance and the lower ice adhesion strength suggest that the super-hydrophobic coatings based on a combination of silica and POTS also show icephobicity. An erosion test rig based on pressurized pneumatic water impinging impact was used to evaluate the durability of the super-hydrophobic/icephobic coatings. The results show that durable coatings have been obtained, although improvement will be needed in future work aiming for applications in aerospace.

  1. Hydrophobic fractal surface from glycerol tripalmitate and the effects on C6 glioma cell growth. (United States)

    Zhang, Shanshan; Chen, Xuerui; Yu, Jing; Hong, Biyuan; Lei, Qunfang; Fang, Wenjun


    To provide a biomimic environment for glial cell culture, glycerol tripalmitate (PPP) has been used as a raw material to prepare fractal surfaces with different degrees of hydrophobicity. The spontaneous formation of the hydrophobic fractal surfaces was monitored by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The surface morphologies were observed by a scanning electron microscope (SEM), and then the fractal dimension (FD) values of the surfaces were determined with the box-counting method. C6 glioma cells were cultured and compared on different hydrophobic PPP surfaces and poly-L-lysine (PLL)-coated surface. The cell numbers as a function of incubation time on different surfaces during the cell proliferation process were measured, and the cell morphologies were observed under a fluorescence microscope. Influences of hydrophobic fractal surfaces on the cell number and morphology were analyzed. The experimental results show that the cell proliferation rates decrease while the cell morphology complexities increase with the growth of the fractal dimensions of the PPP surfaces. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Hydrophobic surface functionalization of lignocellulosic jute fabrics by enzymatic grafting of octadecylamine. (United States)

    Dong, Aixue; Fan, Xuerong; Wang, Qiang; Yu, Yuanyuan; Cavaco-Paulo, Artur


    Enzymatic grafting of synthetic molecules onto lignins provides a mild and eco-friendly alternative for the functionalization of lignocellulosic materials. In this study, laccase-mediated grafting of octadecylamine (OA) onto lignin-rich jute fabrics was investigated for enhancing the surface hydrophobicity. First, the lignins in jute fabrics were isolated and analyzed in the macromolecular level by MALDI-TOF MS, (1)H NMR, (13)C NMR, and HSQC-NMR. Then, the surface of jute fabrics was characterized by FT-IR, XPS, and SEM. Subsequently, the nitrogen content of jute fabrics was determined by the micro-Kjeldahl method, and the grafting percentage (Gp) and grafting efficiency (GE) of the enzymatic reaction were calculated. Finally, the surface hydrophobicity of the jute fabrics was estimated by contact angle and wetting time measurements. The results indicate that the OA monomers were successfully grafted onto the lignin moieties on the jute fiber surface by laccase with Gp and GE values of 0.712% and 10.571%, respectively. Moreover, the modified jute fabrics via OA-grafting showed an increased wetting time of 18.5 min and a contact angle of 116.72°, indicating that the surface hydrophobicity of the jute fabrics increased after the enzymatic grafting modification with hydrophobic OA molecules. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Synthesis of hydrophobic zeolite X-SiO{sub 2} core-shell composites

    Energy Technology Data Exchange (ETDEWEB)

    Liu Liying [School of Material and Metallurgy, Northeastern University, Shenyang, Liaoning 110004 (China); Cooperative Research Centre for Greenhouse Gas Technologies (CO-2CRC) (Australia); Singh, Ranjeet; Li Gang; Xiao Gongkui [Cooperative Research Centre for Greenhouse Gas Technologies (CO-2CRC) (Australia); Department of Chemical Engineering, Monash University, Clayton, Victoria 3800 (Australia); Webley, Paul A., E-mail: [Cooperative Research Centre for Greenhouse Gas Technologies (CO-2CRC) (Australia); Department of Chemical and Biomolecular Engineering, University of Melbourne, Victoria 3010 (Australia); Zhai Yuchun [School of Material and Metallurgy, Northeastern University, Shenyang, Liaoning 110004 (China)


    Highlights: Black-Right-Pointing-Pointer Hydrophobic 13X zeolite composites with silicalite and mesoporous silica shells are designed. Black-Right-Pointing-Pointer These core-shell composites are silynated and their hydrophobicity is tested. Black-Right-Pointing-Pointer Addition of silica layer increases the density of surface hydroxyl groups which makes the improvement of the hydrophobicity possible by further silynation. - Abstract: Core-shell structures of zeolite X coated with silicalite as well as mesoporous (MCM-41) have been synthesized. Furthermore, the surfaces of the silicalite and mesoporous silica shells were silylated using organosilanes. The materials were characterized by X-ray diffraction, nitrogen adsorption/desorption, scanning and transmission electron microscopy. The results show that the properties of zeolite 13X-silicalite and zeolite 13X-mesoporous silica core-shells composite structures are well maintained even after the modification. As expected, the shell thickness increased with increase in synthesis time, however, the micropore volume decreased. Silylation with smaller organosilanes (trimethyl chlorosilane) resulted in decrease in surface area as they diffused through the pores; however, bulkier silane reacted with surface hydroxyl groups and maintained the pore structure. Contact angle measurements revealed that hydrophobicity of zeolite 13X was enhanced by the microporous and mesoporous shell coating and was further improved by silylation.

  4. Numerical Simulation and Experimental Study on Temperature Distribution of Self-Lubricating Packing Rings in Reciprocating Compressors

    Directory of Open Access Journals (Sweden)

    Jia Xiaohan


    Full Text Available The nonuniform abrasion failure and high-temperature thermal failure of packing rings have a significant influence on compressor reliability, particularly that of oil-free compressors. In this study, a test rig was constructed to measure the dynamic temperature of packing rings under different operational conditions in an oil-free reciprocating compressor. The dynamic axial and radial temperature distributions of the packing rings were obtained using an innovative internal temperature testing device that kept the thermocouples and packing box relatively static during compressor operation. A three-dimensional heat transfer model was also developed to analyze the temperature distribution of the packing boxes, piston rod, and cylinder during such operation. Good agreement was observed between the simulation results and experimental data, which showed an average relative error of less than 2.35%. The results indicate that the pressure ratio exerts a significant effect on the axial temperature distribution and determines which packing ring reaches the maximum temperature. They also show the average temperature to rise with an increase in the rotational speed and to fall with an improvement in the external cooling conditions. Finally, the material of the packing rings was found to affect the temperature gradient from their inner to outer surface.

  5. Fabrication of hydrophobic polymethylsilsesquioxane aerogels by a surfactant-free method using alkoxysilane with ionic group

    Directory of Open Access Journals (Sweden)

    Gen Hayase


    Full Text Available Phase separation control is an important factor to prepare a porous monolith by an aqueous sol–gel reaction. Here, we report a surfactant-free synthesis method to obtain hydrophobic polymethylsilsesquioxane aerogels by copolymerizing a cationic-functionalized alkoxysilane N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride. The resultant materials have low-density, high visible-light transmittance, and high thermal insulating equivalent to those of prepared under the presence of surfactant.

  6. Effect of growth times on the physical and mechanical properties of hydrophobic and oleophilic silylated bacterial cellulose membranes (United States)

    Zakaria, M. N.; Sukirah, A. R.; Maizatulnisa, O.; Ayuni, J.; Khalisanni, K.; Rosmamuhamadani, R.


    Bacterial cellulose is an extracellular natural byproduct of the metabolism of various bacteria. Its physical and mechanical properties were determined by growth period, method of cultivation either static or agitate, fermentation condition and medium. Thispaper presented works done on the effect of culture time on the physical and mechanical properties of silylated bacteria cellulose membranes. Bacterial cellulose (BC) growth under 4, 5, 6 and 7 days had been used as a natural reinforcement material and silane as a hydrophobic coating material. With extended culture time, the tensile strength and tensile modulus were increased linearly as result of more compact structure. Due to hydrophobic properties of silane, the water absorption and thickness swelling improved correspondingly. Contact angle testingusing three different liquid proven the functionality of silane as hydrophobic and oleophilic coating agent. The experimental results suggested that hydropobicand oleophilicsilylatedbacteria cellulose membranes with controlled growth time could be prepared and regarded as a reusable oil spills membrane.

  7. Influence of hydrophobic characteristic of organo-modified precursor ...

    Indian Academy of Sciences (India)

    hydrophobicity of the functionalized silica nanoparticles increased as a function of length of the aliphatic chains. (MTES < iTES < OTES) or when, instead of ... hydrophobicity properties (paints or surface treatments) are tributary to the ... nanoparticles can be tailored directly by the hydrolysis reac- tions in aqueous solutions, ...

  8. Hydrophobically modified polyelectrolytes : synthesis, properties and interactions with surfactants

    NARCIS (Netherlands)

    Nieuwkerk, A.C.


    Hydrophobically modified polyelectrolytes can form micelle-like aggregates, so-called microdomains, in aqueous solution. The hydrophobic side chains constitute the apolar inner part of these microdomains and the hydrophilic groups on the polyelectrolyte backbone are at the surface of the

  9. Corrosion protection of reinforcement by hydrophobic treatment of concrete

    NARCIS (Netherlands)

    Polder, R.B.; Vries, H. de


    Penetration of de-icing salts into concrete bridge decks may cause corrosion of reinforcement. Hydrophobic treatment of concrete was studied as additional protection. It was shown that hydrophobic treatment strongly reduces chloride ingress, during semi-permanent contact and in wetting/drying

  10. Hydrophobicity-induced drying transition in alkanethiol self ...

    Indian Academy of Sciences (India)

    This effectively increases the overall thickness of the dielectric layer that is manifested as an abnormally low value of interfacial capacitance. This behaviour is very much akin to the 'drying transition' proposed by Lum, Chandler and Weeks in their theory of length scale dependent hydrophobicity. For small hydrophobic units ...

  11. Hydroglyphics: Demonstration of Selective Wetting on Hydrophilic and Hydrophobic Surfaces (United States)

    Kim, Philseok; Alvarenga, Jack; Aizenberg, Joanna; Sleeper, Raymond S.


    A visual demonstration of the difference between hydrophilic and hydrophobic surfaces has been developed. It involves placing a shadow mask on an optically clear hydrophobic plastic dish, corona treating the surface with a modified Tesla coil, removing the shadow mask, and visualizing the otherwise invisible message or pattern by applying water,…

  12. Adsorption of antimicrobial indolicidin-derived peptides on hydrophobic surfaces. (United States)

    Tsai, Ching-Wei; Ruaan, Ruoh-Chyu; Liu, Chih-I


    The hydrophobic interaction between antimicrobial peptides and membrane hydrophobic cores is usually related to their cytotoxicity. In this study, the adsorption mechanism of five plasma membrane-associated peptides, indolicidin (IL) and its four derivatives, with hydrophobic ligands was investigated to understand the relationship between peptide hydrophobicity and bioactivity. The hydrophobic adsorption mechanisms of IL and its derivatives were interpreted thermodynamically and kinetically by reversed-phase chromatography (RPC) analysis and surface plasmon resonance (SPR) measurement, respectively. IL and its derivatives possess a similar random coil structure in both aqueous and organic solvents. Thermodynamic analysis showed that the binding enthalpy of peptides with higher electropositivity was lower than those with lower electropositivity and exhibited unfavorable binding entropy. Higher electropositivity peptides adsorbed to the hydrophobic surface arising from the less bound solvent on the peptide surface. A comparison with the kinetic analysis showed that IL and its derivatives adopt a two-state binding model (i.e., adsorption onto and self-association on the hydrophobic acyl chain) to associate with the hydrophobic surface, and the binding affinity of peptide self-association correlates well with peptide hemolysis. Consequently, this study provided a novel concept for understanding the action of plasma membrane-associated peptides.

  13. Hydrophobic effect of silica functionalized with silylated Ti ...

    Indian Academy of Sciences (India)

    ) to induce hydrophobicity. The composition of the ... Hydrophobicity; silylation; silica functionalized with silyated Ti-salicylaldimine complex; limonene oxidation ... lysts, such as TiO2-zeolite,3 Ti-SBA-15,4 Ti-POM,5 Ti-. MCM-416 and others, ...

  14. A conserved hydrophobic patch on Vβ domains revealed by TCRβ chain crystal structures: implications for pre-TCR dimerization

    Directory of Open Access Journals (Sweden)

    Bo eZhou


    Full Text Available The αβ T cell receptor (TCR is a multimeric complex whose β chain plays a crucial role in thymocyte development as well as antigen recognition by mature T lymphocytes. We report here crystal structures of individual β subunits, termed N15β (Vβ5.2Dβ2Jβ2.6Cβ2 and N30β (Vβ13Dβ1Jβ1.1Cβ2, derived from two αβ TCRs specific for the immunodominant Vesicular Stomatitis Virus octapeptide (VSV-8 bound to the murine H-2Kb MHC classⅠmolecule. The crystal packing of the N15β structure reveals a homodimer formed through two Vβ domains. The Vβ/Vβ module is topologically very similar to the Vα/Vβ module in the N15αβ heterodimer. By contrast, in the N30β structure, the Vβ domain’s external hydrophobic CFG face is covered by the neighboring molecule’s Cβ domain. In conjunction with systematic investigation of previously published TCR single subunit structures, we identified several conserved residues forming a concave hydrophobic patch at the center of the CFG outer face of the Vβ and other V-type Ig-like domains. This hydrophobic patch is shielded from solvent exposure in the crystal packing, implying that it is unlikely to be thermodynamically stable if exposed on the thymocyte surface. Accordingly, we propose a dimeric pre-TCR model distinct from those suggested previously by others and discuss its functional and structural implications.

  15. Olive and olive pomace oil packing and marketing

    Directory of Open Access Journals (Sweden)

    Berzosa, Juan


    Full Text Available The paper describes the industrial installations and equipments used by the olive oil sector for olive oil packing, the different types of containers used (plastic, glass, tin, and carton, and the diverse technologies applied for filling, stoppering, labelling, and packing as well as the trend and new technologies developed according to the material of the containers and the markets’ demands.Some logistic aspects such as palletization, storage, and shipment of final products are also discussed. The use of modern tools and codification systems like EAN 128 permits to follow the product distribution and assure the traceability of packed oils.The last part of the article includes the world and EU production and consumption of olive oil, paying special attention to the peculiarities of the main EU producers (Spain, Italy, Greece, and Portugal. Finally, the olive oil consumption in third countries is analysed and the consumption and its trend in merging markets like USA, Australia, and Japan commented.En este artículo se describen los equipos e instalaciones industriales que utiliza el sector del aceite de oliva para el envasado de los aceites de oliva, los tipos de envases más empleados (plástico, vidrio, metálicos y cartón y las diferentes tecnologías de llenado, taponado, etiquetado y embalado, así como las tendencias y nuevas tecnologías en función del material de los envases y la demanda de los mercados.Se contemplan también aspectos logísticos como el paletizado, el almacenamiento y la expedición del producto terminado. El uso de modernas herramientas y sistemas de codificación como el EAN 128 permite el seguimiento del producto y la trazabilidad de los aceites envasados a lo largo de la cadena de distribución.En la última parte del artículo, se indican cifras de producción y consumo de aceite de oliva en el mundo y en la Unión Europea. Se comentan especialmente las peculiaridades de los principales países productores de la

  16. Experimental insights of liquid impacts onto granular beds of various packings : The packing influence over the excavated volumes (United States)

    Wyser, Emmanuel; Carrea, Dario; Jaboyeodff, Michel


    Most of the past studies focused on solid impacts onto granular beds addressing key questions such as the crater dimensions or the impactor deceleration. Recent investigations were oriented toward the more complex case of liquid-to-granular impacts. However, the influence of the packing over the impact process and the bed response is not clearly understood. Moreover, we may assume the general scaling law which relates the average crater volume to the kinetic energy is invariant regarding the impact type (solid-to-granular, liquid-to-granular). Hence, we address the influence of the granular bed packing over both the excavated & deposited volumes. We propose to study liquid-to-granular impacts via an experimental protocol, which is described in the following. A device releases 2.34±0.14 mm radii water droplets, which vertically fall from different heights (50, 100, 200 & 290 mm) onto fine granular samples (d50 = 0.0357 mm) of diameter 400 mm. Each granular sample was previously compacted using a heavy circular plate and a shaking device. Pre and post-impacts geometries are acquired using a 3D scanner, which is the KONICA MINOLTA VIVID 9i fitted with a TELE lens 25 mm with a focal distance of 25 mm and a theoretical vertical precision of 0.008 mm with a standard deviation of 0.024 mm. High density 3D point clouds result from this experimental procedure. Spatial changes are then characterized and provide a quantification of excavated & deposited volumes or local granular bed uplifts. We observe a common pattern for every impacts: the local granular bed uplift at the periphery of the impact center. This shows the difficulty to distinguish deposited materials from uplifted materials. Achieving distinction between deposition and uplift process leads to an average uplift-induced volume proportion of 0.94-0.97 (i.e. the ratio between deposited volume and uplift-induced volume), which illustrates the high dissipation of energy The granular bed packing influence is clearly

  17. Protein-induced bilayer Perturbations: Lipid ordering and hydrophobic coupling

    DEFF Research Database (Denmark)

    Petersen, Frederic Nicolas Rønne; Laursen, Ib; Bohr, Henrik


    The host lipid bilayer is increasingly being recognized as an important non-specific regulator of membrane protein function. Despite considerable progress the interplay between hydrophobic coupling and lipid ordering is still elusive. We use electron spin resonance (ESR) to study the interaction...... and hydrophobic mismatch. Our findings also show that at high protein:lipid ratios the lipids are motionally restricted but not completely immobilized. Both exchange on and off rate values for the lipid ↔ gramicidin interaction are lowest at optimal hydrophobic matching. Hydrophobic mismatch of few Å results...... in up to 10-fold increased exchange rates as compared to the ‘optimal’ match situation pointing to the regulatory role of hydrophobic coupling in lipid–protein interactions....

  18. Multi-pack Disposal Concepts for Spent Fuel (Rev. 0)

    Energy Technology Data Exchange (ETDEWEB)

    Hadgu, Teklu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hardin, Ernest [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Matteo, Edward N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    At the initiation of the Used Fuel Disposition (UFD) R&D campaign, international geologic disposal programs and past work in the U.S. were surveyed to identify viable disposal concepts for crystalline, clay/shale, and salt host media (Hardin et al., 2012). Concepts for disposal of commercial spent nuclear fuel (SNF) and high-level waste (HLW) from reprocessing are relatively advanced in countries such as Finland, France, and Sweden. The UFD work quickly showed that these international concepts are all “enclosed,” whereby waste packages are emplaced in direct or close contact with natural or engineered materials . Alternative “open” modes (emplacement tunnels are kept open after emplacement for extended ventilation) have been limited to the Yucca Mountain License Application Design (CRWMS M&O, 1999). Thermal analysis showed that, if “enclosed” concepts are constrained by peak package/buffer temperature, waste package capacity is limited to 4 PWR assemblies (or 9-BWR) in all media except salt. This information motivated separate studies: 1) extend the peak temperature tolerance of backfill materials, which is ongoing; and 2) develop small canisters (up to 4-PWR size) that can be grouped in larger multi-pack units for convenience of storage, transportation, and possibly disposal (should the disposal concept permit larger packages). A recent result from the second line of investigation is the Task Order 18 report: Generic Design for Small Standardized Transportation, Aging and Disposal Canister Systems (EnergySolution, 2015). This report identifies disposal concepts for the small canisters (4-PWR size) drawing heavily on previous work, and for the multi-pack (16-PWR or 36-BWR).

  19. Multi-Pack Disposal Concepts for Spent Fuel (Revision 1)

    Energy Technology Data Exchange (ETDEWEB)

    Hardin, Ernest [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Matteo, Edward N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hadgu, Teklu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    At the initiation of the Used Fuel Disposition (UFD) R&D campaign, international geologic disposal programs and past work in the U.S. were surveyed to identify viable disposal concepts for crystalline, clay/shale, and salt host media. Concepts for disposal of commercial spent nuclear fuel (SNF) and high-level waste (HLW) from reprocessing are relatively advanced in countries such as Finland, France, and Sweden. The UFD work quickly showed that these international concepts are all “enclosed,” whereby waste packages are emplaced in direct or close contact with natural or engineered materials . Alternative “open” modes (emplacement tunnels are kept open after emplacement for extended ventilation) have been limited to the Yucca Mountain License Application Design. Thermal analysis showed that if “enclosed” concepts are constrained by peak package/buffer temperature, that waste package capacity is limited to 4 PWR assemblies (or 9 BWR) in all media except salt. This information motivated separate studies: 1) extend the peak temperature tolerance of backfill materials, which is ongoing; and 2) develop small canisters (up to 4-PWR size) that can be grouped in larger multi-pack units for convenience of storage, transportation, and possibly disposal (should the disposal concept permit larger packages). A recent result from the second line of investigation is the Task Order 18 report: Generic Design for Small Standardized Transportation, Aging and Disposal Canister Systems. This report identifies disposal concepts for the small canisters (4-PWR size) drawing heavily on previous work, and for the multi-pack (16-PWR or 36-BWR).

  20. Assessment of pack animal welfare in and around Bareilly city of India

    Directory of Open Access Journals (Sweden)

    Probhakar Biswas


    Full Text Available Aim: To assess the welfare of pack animal: Pony, Horse, Mule and Donkey in and around Bareilly city. Materials and Methods: The present study was carried out in Bareilly city and Izatnagar area of Bareilly district of Uttar Pradesh in the year 2009. Representative sample of 100 pack animal owners were selected to get the information regarding various social, personal and economic attributes of the pack animal. Further during interviewing different health and behavior pattern of animals was keenly examined. Analysis has been done as per standard procedures. Results: Most of the pack animal owners (98% were aware of the freedom from hunger and thirst. Majority of respondents (96, 93, 81 & 85 percent were aware of freedom from injury and disease, pain and discomfort, to express normal behavior and adequate space and freedom from fear and distress. Respondents (85% believed that they themselves were responsible for the welfare of the animals. Most of the owners (48.8% employed their animals for work for 9-10 hrs with rest (96.5% in between work and most (88.3% indulged into beating to compel the animals to work. All pregnant animals were put to work in the first two trimesters of pregnancy. Upon physical examination, pack animals showed abnormality in eyes (49%, abnormality in gait (40% and limb deformity (39%. Most animals (75% had tether lesions and 34 percent animals avoided or were aggressive to observer. Majority (74.1% of the owners housed their animals in a part of their own residence with improper drainage and cleaning. Most of the owners (82% consulted Veterinary doctors for treatment and believed in allopathic medicine (57%. Vaccination was not carried out on most (96% of the animals. All the animals were feed green fodder but practice of supplementation of minerals to animals was only among 11 percent owners. Conclusions: Present findings provide baseline information on welfare activities followed by pack animal owners and status of pack

  1. The Effect of Particle Size Dispersity in Dense Granular Packings on the Void Structure and the Interparticle Contact Frictional State (United States)

    Dutt, Meenakshi; Elliott, James A.


    The response of a granular packing to external forcing is dependent upon particle properties such as the size and material stiffness; void structure and packing history. This question is pertinent in systems spanning a large range in length scales: for example, in geophysical systems such as ocean beds, or pharmaceutical powder compacts, such as tablets. We are interested in exploring the relationship between the particle size distribution in a granular packing and the evolving void structure under a compressive strain. We generate the packings by allowing the particles to settle under gravity for a fixed interval of time, or until a cut-off packing fraction is attained, followed by application of a compressive strain for a fixed interval of time, for samples of discrete size distributions(200 microns, 195-225 microns , 170-260 microns, 150-295 microns). We find a higher compressive strain is required to attain the same packing fraction for samples of increasing particle size distribution. In addition, the fraction of plastic contacts decreases with increasing variation in particle size during the compression. We link the particle size distribution to the response of a granular material to compressive strain by using a combination of contact frictional state and void structure calculations (Dutt, Elliott, et al., submitted). The void structure calculations are performed via a dynamically tesselating algorithm which calculates the pore network in dense particulate systems (Benedict, Dutt Elliott, Physica A).

  2. A rheological study of hydrophobic-surface-active polymer systems structuration; Etude rheologique de la structuration de systemes polymere hydrophobe-tensioactif

    Energy Technology Data Exchange (ETDEWEB)

    Heinrich, E.


    This work deals with the study of the rheology and the structuration of hydrophobic polymer and surfactant systems. The used associative polymers are acrylamide/nonyl methacrylate copolymers and the surfactant is nonionic. They are particularly used for hydrocarbons extraction techniques as drilling (drilling fluids) or wells cementation. The studied materials are first characterized by different analytic techniques. This preliminary stage of the work gives a good insight of the physico-chemical parameters of the systems. The effect of surfactant was shown by studying the variation of Newtonian viscosity as a function of surfactant concentration. This yields bell curves, whose maximum determines the critical aggregation concentration (cac). The hydrophobic effect is analysed in different polymer concentration regimes, in quasi-static conditions, and under shear. The study of the dynamic visco-elasticity of semi-dilute solutions allows to observe the effect of the hydrophobic associations on the relaxation time of the chains. The system can be described as a superposition of two networks of junctions: the network of physical entanglements and a second one formed by the hydrophobic links. Phenomena of structuration have been observed at room temperature for surfactant concentrations close to the cac. The increase of viscosity or elastic modulus can be 3 to 4 orders of magnitude. The effect of the temperature on the structure of the systems is studied as well. The rheological characterization of the Sol-Gel transition is developed and the rheological behavior of the solutions in a structured state shows a critical stress for rupture of the structure. Microscopic observations of the birefringence of the solutions display the existence of lamellar vesicles, which leads to the following assumption: the formation of big spherulites create a rigidification of the macromolecular network. (author) 190 refs.

  3. Meal Module, Tray Pack 36-Persons (United States)


    17.50 7.8 0.19 20 Potatoes in 8940-01-152-6821 5.50 7.6 0.19 18 Butter Sauce Green Beans 8915-01-150-2861 7.99 5.0 0.19 25 Apple Dessert 8940-01-147-7855...CUSHIONED HOT SAUCE 8. BOXES OF PEANUT BUTTER PACKETS 9. BOX OF COFFEE PACKETS 10. BOX OF CREAMER PACKETS Figure 10. Meal Module, Tray Pack, 36...listed Condiments (Table A-3) as listed Breakfast 2 Fruit Cocktail w/Syrup 8915-00-286-5482 S Beef Stew 8940-01-009-7993 Mixed Vegetables 8915-01-173-2858

  4. Ideal Clutters That Do Not Pack (United States)


    class of objects, called marginal cuboids, that naturally give rise to ideal non-packing clutters with covering number two. We present an explicit...class of marginal cuboids, and show that the corresponding clutters have one of Q6, Q2,1, Q10 as a minor, where Q6, Q2,1 are known ideal mnp clutters...clutter C0 where τ(C0) = 2, and (iv) C0 is a marginal cuboid. This result is proved in §5. We will define marginal cuboids shortly. Statement (iv

  5. Intrinsic Dispersivity of Randomly Packed Monodisperse Spheres (United States)

    Scheven, U. M.; Harris, R.; Johns, M. L.


    We determine the intrinsic longitudinal dispersivity ld of randomly packed monodisperse spheres by separating the intrinsic stochastic dispersivity ld from dispersion by unavoidable sample dependent flow heterogeneities. The measured ld, scaled by the hydrodynamic radius rh, coincide with theoretical predictions [Saffman, J. Fluid Mech. 7, 194 (1960)JFLSA70022-112010.1017/S0022112060001432] for dispersion in an isotropic random network of identical capillaries of length l and radius a, for l/a=3.82, and with rescaled simulation results [Maier et al., Phys. FluidsPHFLE61070-6631 12, 2065 (2000)10.1063/1.870452].

  6. Solubilization of Hydrophobic Dyes in Surfactant Solutions

    Directory of Open Access Journals (Sweden)

    Ali Reza Tehrani-Bagha


    Full Text Available In this paper, the use of surfactants for solubilization of hydrophobic organic dyes (mainly solvent and disperse dyes has been reviewed. The effect of parameters such as the chemical structures of the surfactant and the dye, addition of salt and of polyelectrolytes, pH, and temperature on dye solubilization has been discussed. Surfactant self-assemble into micelles in aqueous solution and below the concentration where this occurs—the critical micelle concentration (CMC—there is no solubilization. Above the CMC, the amount of solubilized dye increases linearly with the increase in surfactant concentration. It is demonstrated that different surfactants work best for different dyes. In general, nonionic surfactants have higher solubilization power than anionic and cationic surfactants. It is likely that the reason for the good performance of nonionic surfactants is that they allow dyes to be accommodated not only in the inner, hydrocarbon part of the micelle but also in the headgroup shell. It is demonstrated that the location of a dye in a surfactant micelle can be assessed from the absorption spectrum of the dye-containing micellar solution.

  7. Targeting of the hydrophobic metabolome by pathogens. (United States)

    Helms, J Bernd; Kaloyanova, Dora V; Strating, Jeroen R P; van Hellemond, Jaap J; van der Schaar, Hilde M; Tielens, Aloysius G M; van Kuppeveld, Frank J M; Brouwers, Jos F


    The hydrophobic molecules of the metabolome - also named the lipidome - constitute a major part of the entire metabolome. Novel technologies show the existence of a staggering number of individual lipid species, the biological functions of which are, with the exception of only a few lipid species, unknown. Much can be learned from pathogens that have evolved to take advantage of the complexity of the lipidome to escape the immune system of the host organism and to allow their survival and replication. Different types of pathogens target different lipids as shown in interaction maps, allowing visualization of differences between different types of pathogens. Bacterial and viral pathogens target predominantly structural and signaling lipids to alter the cellular phenotype of the host cell. Fungal and parasitic pathogens have complex lipidomes themselves and target predominantly the release of polyunsaturated fatty acids from the host cell lipidome, resulting in the generation of eicosanoids by either the host cell or the pathogen. Thus, whereas viruses and bacteria induce predominantly alterations in lipid metabolites at the host cell level, eukaryotic pathogens focus on interference with lipid metabolites affecting systemic inflammatory reactions that are part of the immune system. A better understanding of the interplay between host-pathogen interactions will not only help elucidate the fundamental role of lipid species in cellular physiology, but will also aid in the generation of novel therapeutic drugs. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Biomimetic hydrophobic surface fabricated by chemical etching method from hierarchically structured magnesium alloy substrate

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yan; Yin, Xiaoming; Zhang, Jijia [Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China); Wang, Yaming [Institute for Advanced Ceramics, Harbin Institute of Technology, Harbin 150001 (China); Han, Zhiwu, E-mail: [Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China); Ren, Luquan [Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China)


    As one of the lightest metal materials, magnesium alloy plays an important role in industry such as automobile, airplane and electronic product. However, magnesium alloy is hindered due to its high chemical activity and easily corroded. Here, inspired by typical plant surfaces such as lotus leaves and petals of red rose with super-hydrophobic character, the new hydrophobic surface is fabricated on magnesium alloy to improve anti-corrosion by two-step methodology. The procedure is that the samples are processed by laser first and then immersed and etched in the aqueous AgNO{sub 3} solution concentrations of 0.1 mol/L, 0.3 mol/L and 0.5 mol/L for different times of 15 s, 40 s and 60 s, respectively, finally modified by DTS (CH{sub 3}(CH{sub 2}){sub 11}Si(OCH{sub 3}){sub 3}). The microstructure, chemical composition, wettability and anti-corrosion are characterized by means of SEM, XPS, water contact angle measurement and electrochemical method. The hydrophobic surfaces with microscale crater-like and nanoscale flower-like binary structure are obtained. The low-energy material is contained in surface after DTS treatment. The contact angles could reach up to 138.4 ± 2°, which hydrophobic property is both related to the micro–nano binary structure and chemical composition. The results of electrochemical measurements show that anti-corrosion property of magnesium alloy is improved. Furthermore, our research is expected to create some ideas from natural enlightenment to improve anti-corrosion property of magnesium alloy while this method can be easily extended to other metal materials.

  9. Immobilized Coprinus plicatilis Biodegradation of Fluorene in Two Different Packed-Bed Reactors. (United States)

    Akdogan, Hatice Ardag


    The biodegradation of fluorene by immobilized Coprinus plicatilis was studied in pinewood and foam glass bead-packed reactors. The reactors were operated in a sequencing batch system. Removal efficiency increased over time and elevated influent fluorene concentration (85 mg/L) was removed 100% in 24-30 h batch cycles. Increased laccase activity was detected with the introduction of the compounds, and optimum activity corresponded to optimum removal periods. Significantly higher laccase activity (16.7-19 U/L) was detected in the glass bead-packed reactor compared to the pinewood-packed reactor (0.2-5 U/L). The presence of Mn2+ ions in the wood material possibly caused elevated manganese peroxidase activity (0.3-5.8 U/L) compared to low to negligible activity in the glass bead reactor. Reactor performances are discussed in relation to sequencing batch operation and nutrient requirements necessary to induce and sustain fungal enzyme activity in inert-like organic material packed systems. Biodegradation metabolites were detected in samples via GC/MS.

  10. The "sugar pack" health marketing campaign in Los Angeles County, 2011-2012. (United States)

    Barragan, Noel C; Noller, Ali J; Robles, Brenda; Gase, Lauren N; Leighs, Michael S; Bogert, Suzanne; Simon, Paul A; Kuo, Tony


    As part of a comprehensive approach to combating the obesity epidemic, the Los Angeles County Department of Public Health launched the "Sugar Pack" health marketing campaign in fall 2011. Carried out in three stages, the campaign sought to educate and motivate the public to reduce excess calorie intake from sugar-sweetened beverage consumption. The primary Sugar Pack creative concepts provided consumers with information about the number of sugar packs contained in sugary drinks. Data from formative market research as well as lessons from previous campaigns in other U.S. jurisdictions informed the development of the materials. These materials were disseminated through a multipronged platform that included paid outdoor media on transit and billboards and messaging using social media (i.e., Twitter, Facebook, YouTube, and sendable e-cards). Initial findings from a postcampaign assessment indicate that the Sugar Pack campaign reached broadly into targeted communities, resulting in more than 515 million impressions. Lessons learned from the campaign suggest that employing health marketing to engage the public can lead to increased knowledge, favorable recognition of health messages, and self-reported intention to reduce sugar-sweetened beverage consumption, potentially complementing other obesity prevention strategies in the field.

  11. Adhesion of Cryptosporidium parvum and Giardia lamblia to solid surfaces: the role of surface charge and hydrophobicity

    NARCIS (Netherlands)

    Dai, X.; Boll, J.; Hayes, M.E.; Aston, D.E.


    Adhesion of Cryptosporidium parvum and Giardia lamblia to four materials of different surface charge and hydrophobicity was investigated. Glass beads were used with and without three polymer coatings: aminosilines (A0750), fluorosilines (T2494), an amino cationic polymer. Surface charge density and

  12. Contaminant bacteria in traditional-packed honey

    Directory of Open Access Journals (Sweden)

    Hening Tjaturina Pramesti


    Full Text Available Honey may be contaminated by microorganisms during its harvesting, processing, and packaging. Honey selected for clinical purposes must safe, sterile, and contain antimicrobial activity, so it must be evaluated using laboratory testing. The aim of this descriptive laboratory study was to isolate and identify the bacterial contaminant in the traditional-packed honey dealing with the use of honey for medical purposes. the colony forming units of honey sample cultured on blood agar were counted using Stuart bacterial colony counter. The suspected bacterial colonies were isolated and identified based on cultural morphology characteristics. The isolates of suspected bacterial colonies were stained according to Gram and Klein method and then were examined by the biochemical reaction. The results showed that there were two contaminant bacteria. Gram-positive cocci which were presumptively identified as coagulase-negative Staphylococci and gram-positive rods which were presumptively identified as Bacillus subtilis. In conclusion, the contaminant bacteria were regarded as low pathogen bacteria. The subtilin enzyme of B subtilis may cause an allergic reaction and coagulase-negative Staphylococci, Staphylococcus epidermidis is also an opportunist pathogen. Inevitably, for medical purposes, traditional-packed honey must be well filtered, water content above 18%, and standardized sterilization without loss of an antibacterial activity or change in properties.

  13. Protein packing defects "heat up" interfacial water. (United States)

    Sierra, María Belén; Accordino, Sebastián R; Rodriguez-Fris, J Ariel; Morini, Marcela A; Appignanesi, Gustavo A; Fernández Stigliano, Ariel


    Ligands must displace water molecules from their corresponding protein surface binding site during association. Thus, protein binding sites are expected to be surrounded by non-tightly-bound, easily removable water molecules. In turn, the existence of packing defects at protein binding sites has been also established. At such structural motifs, named dehydrons, the protein backbone is exposed to the solvent since the intramolecular interactions are incompletely wrapped by non-polar groups. Hence, dehydrons are sticky since they depend on additional intermolecular wrapping in order to properly protect the structure from water attack. Thus, a picture of protein binding is emerging wherein binding sites should be both dehydrons rich and surrounded by easily removable water. In this work we shall indeed confirm such a link between structure and dynamics by showing the existence of a firm correlation between the degree of underwrapping of the protein chain and the mobility of the corresponding hydration water molecules. In other words, we shall show that protein packing defects promote their local dehydration, thus producing a region of "hot" interfacial water which might be easily removed by a ligand upon association.

  14. Comparing Electrolytes in Prestorage Leukocyte-Reduced Packed Cell versus Unfiltered Packed Cell. (United States)

    Fallahi, L; Ghiliyan, R; Hashemi, A; Fatemi, A; Saeedi, M


    Blood transfusion is associated with side effects caused by residual leukocytes in blood and blood components. Using leukodepleted blood components can decrease some of these adverse effects. Among the various methods to remove leukocytes in blood components, prestorage leukoreduction has been most efficient, but the evidence of clinical side effects awaits further studies. We evaluated changes of electrolytes in prestorage leukocyte-reduced red blood cells. In this case-control study, one hundred twenty eight packed cells were studied: 64 unfiltered packed cells and 64 prestorage filtered packed cell. Two groups were matched as sex and age. Electrolytes such as Calcium, Sodium, and Potassium of two groups were measured, and compared during preparation. In this study, mean of Calcium in unfiltered and filtered group were 6.16±1.09 mg/dl and 5.57±2.21 mg/dl, respectively (P-valueunfiltered group also was 155.91+/-9.51meq/l and in filtered group, 153.05+/-13.21meq/l (P-valueunfiltered group was 5.01+/-1.72 meq/l and in filtered group, 7.42+/-2.45meq/l (P-value<0.001). Releasing of Potassium during preparation of prestorage leukoreduction can cause increased Potassium level and hemoglobin concentration changes in prestorage filtered packed cell.

  15. Thermodynamics of hydrophobic interaction between silica surfaces coated with octadecyltrichlorosilane. (United States)

    Li, Zuoli; Yoon, Roe-Hoan


    Surface force measurements conducted with thiolated gold surfaces showed previously that hydrophobic interaction entails a decrease in excess film entropy, suggesting that hydrophobic force originates from changes in the structure of the medium (water) confined between hydrophobic surfaces. As a follow-up work, surface force measurements have been conducted in the present work using an atomic force microscope (AFM) with silica surfaces coated with octadecyltrichlorosilane (OTS) at temperatures in the range of 10-40°C. A thermodynamic analysis of the results show that both the excess film entropy (ΔS(f)) and excess film enthalpy (ΔH(f)) decrease with decreasing thickness of the water films between the hydrophobic surfaces. It has been found also that |ΔH(f)|>|TΔS(f)|, which represents a necessary condition for the excess free energy change (ΔG(f)) to be negative and hence the hydrophobic interaction be attractive. Thus, the results obtained with both the thiolated and silylated surfaces show that hydrophobic forces originate from the structural changes in the medium. It is believed that the water molecules in the thin liquid films (TLFs) of water form clusters as a means to reduce the free energy when they cannot form H-bonds to neighboring hydrophobic surfaces. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Heat insulation performance, mechanics and hydrophobic modification of cellulose-SiO2 composite aerogels. (United States)

    Shi, Jianjun; Lu, Lingbin; Guo, Wantao; Zhang, Jingying; Cao, Yang


    Cellulose-SiO2 composite hydrogel was prepared by combining the NaOH/thiourea/H2O solvent system and the immersion method with controlling the hydrolysis-fasculation rate of tetraethyl orthosilicate (TEOS). The hydrophobic composite aerogels were obtained through the freeze-drying technology and the cold plasma modification technology. Composite SiO2 could obviously reduce the thermal conductivity of cellulose aerogel. The thermal conductivity could be as low as 0.026 W/(mK). The thermal insulation mechanism of the aerogel material was discussed. Composite SiO2 reduced hydrophilicity of cellulose aerogel, but environmental humidity had a significant influence on heat insulation performance. After hydrophobic modification using CCl4 as plasma was conducted, the surface of composite aerogel was changed from hydrophilic to hydrophobic and water contact angle was as high as 132°. The modified composite aerogel still kept good heat insulation performance. This work provided a foundation for the possibility of applying cellulose-SiO2 composite aerogel in the insulating material field. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Hydrophobic, Flexible, and Lightweight MXene Foams for High-Performance Electromagnetic-Interference Shielding. (United States)

    Liu, Ji; Zhang, Hao-Bin; Sun, Renhui; Liu, Yafeng; Liu, Zhangshuo; Zhou, Aiguo; Yu, Zhong-Zhen


    Ultrathin, lightweight, and flexible electromagnetic-interference (EMI) shielding materials are urgently required to manage increasingly serious radiation pollution. 2D transition-metal carbides (MXenes) are considered promising alternatives to graphene for providing excellent EMI-shielding performance due to their outstanding metallic electrical conductivity. However, the hydrophilicity of MXene films may affect their stability and reliability when applied in moist or wet environments. Herein, for the first time, an efficient and facile approach is reported to fabricate freestanding, flexible, and hydrophobic MXene foam with reasonable strength by assembling MXene sheets into films followed by a hydrazine-induced foaming process. In striking contrast to well-known hydrophilic MXene materials, the MXene foams surprisingly exhibit hydrophobic surfaces and outstanding water resistance and durability. More interestingly, a much enhanced EMI-shielding effectiveness of ≈70 dB is achieved for the lightweight MXene foam as compared to its unfoamed film counterpart (53 dB) due to the highly efficient wave attenuation in the favorable porous structure. Therefore, the hydrophobic, flexible, and lightweight MXene foam with an excellent EMI-shielding performance is highly promising for applications in aerospace and portable and wearable smart electronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Influence of hydrophobic modification in alginate-based hydrogels for biomedical applications (United States)

    Choudhary, Soumitra

    Alginate has been exploited commercially for decades in foods, textiles, paper, pharmaceutical industries, and also as a detoxifier for removing heavy metals. Alginate is also popular in cell encapsulation because of its relatively mild gelation protocol and simple chemistry with which biological active entities can be immobilized. Surface modification of alginate gels has been explored to induce desired cell interactions with the gel matrix. These modifications alter the bulk properties, which strongly determine on how cells feel and response to the three-dimensional microenvironment. However, there is a need to develop strategies to engineer functionalities into bulk alginate hydrogels that not only preserve their inherent qualities but are also less toxic. In this thesis, our main focus was to optimize the mechanical properties of alginate-based hydrogels, and by doing so control the performance of the biomaterials. In the first scheme, we used alginate and hydrophobically modified ethyl hydroxy ethyl cellulose as components in interpenetrating polymer network (IPN) gels. The second network was used to control gelation time and rheological properties. We believe these experiments also may provide insight into the mechanical and structural properties of more complex biopolymer gels and naturally-occurring IPNs. Next, we worked on incorporating a hydrophobic moiety directly into the alginate chain, resulting in materials for extended release of hydrophobic drugs. We successfully synthesized hydrophobically modified alginate (HMA) by attaching octylamine groups onto the alginate backbone by standard carbodiimide based amide coupling reaction. Solubility of several model hydrophobic drugs in dilute HMA solutions was found to be increased by more than an order of magnitude. HMA hydrogels, prepared by crosslinking the alginate chains with calcium ions, were found to exhibit excellent mechanical properties (modulus ˜100 kPa) with release extended upto 5 days. Ability

  19. Characterization of molecular determinants of the conformational stability of macrophage migration inhibitory factor: leucine 46 hydrophobic pocket.

    Directory of Open Access Journals (Sweden)

    Farah El-Turk

    Full Text Available Macrophage Migration Inhibitory Factor (MIF is a key mediator of inflammatory responses and innate immunity and has been implicated in the pathogenesis of several inflammatory and autoimmune diseases. The oligomerization of MIF, more specifically trimer formation, is essential for its keto-enol tautomerase activity and probably mediates several of its interactions and biological activities, including its binding to its receptor CD74 and activation of certain signaling pathways. Therefore, understanding the molecular factors governing the oligomerization of MIF and the role of quaternary structure in modulating its structural stability and multifunctional properties is crucial for understanding the function of MIF in health and disease. Herein, we describe highly conserved intersubunit interactions involving the hydrophobic packing of the side chain of Leu46 onto the β-strand β3 of one monomer within a hydrophobic pocket from the adjacent monomer constituted by residues Arg11, Val14, Phe18, Leu19, Val39, His40, Val41, Val42, and Pro43. To elucidate the structural significance of these intersubunit interactions and their relative contribution to MIF's trimerization, structural stability and catalytic activity, we generated three point mutations where Leu46 was replaced by glycine (L46G, alanine (L46A and phenylalanine (L46F, and their structural properties, stability, oligomerization state, and catalytic activity were characterized using a battery of biophysical methods and X-ray crystallography. Our findings provide new insights into the role of the Leu46 hydrophobic pocket in stabilizing the conformational state of MIF in solution. Disrupting the Leu46 hydrophobic interaction perturbs the secondary and tertiary structure of the protein but has no effect on its oligomerization state.

  20. In-line gas chromatographic apparatus for measuring the hydrophobic micropore volume (HMV) and contaminant transformation in mineral micropores. (United States)

    Cheng, Hefa; Reinhard, Martin


    Desorption of hydrophobic organic compounds from micropores is characteristically slow compared to surface adsorption and partitioning. The slow-desorbing mass of a hydrophobic probe molecule can be used to calculate the hydrophobic micropore volume (HMV) of microporous solids. A gas chromatographic apparatus is described that allows characterization of the sorbed mass with respect to the desorption rate. The method is demonstrated using a dealuminated zeolite and an aquifer sand as the model and reference sorbents, respectively, and trichloroethylene (TCE) as the probe molecule. A glass column packed with the microporous sorbent is coupled directly to a gas chromatograph that is equipped with flame ionization and electron capture detectors. Sorption and desorption of TCE on the sorbent was measured by sampling the influent and effluent of the column using a combination of switching and injection valves. For geosorbents, the HMV is quantified based on Gurvitsch's rule from the mass of TCE desorbed at a rate that is characteristic for micropores. Instrumental requirements, design considerations, hardware details, detector calibration, performance, and data analysis are discussed along with applications. The method is novel and complements traditional vacuum gravimetric and piezometric techniques, which quantify the total pore volume under vacuum conditions. The HMV is more relevant than the total micropore volume for predicting the fate and transport of organic contaminants in the subsurface. Sorption in hydrophobic micropores strongly impacts the mobility of organic contaminants, and their chemical and biological transformations. The apparatus can serve as a tool for characterizing microporous solids and investigating contaminant-solid interactions. 2010 Elsevier B.V. All rights reserved.

  1. Optical properties of voltage sensitive hemicyanine dyes of variable hydrophobicity confined within surfactant micelles (United States)

    Naeem, Kashif; Naseem, Bushra; Shah, S. S.; Shah, Syed W. H.


    The optical properties of amphiphilic hemicyanine dyes with variable hydrophobicity, confined within anionic micelles of sodium dodecylbenzenesulfonate (NaDDBS) have been studied by UV–visible absorption spectroscopy. The confinement constant, K conf has been determined for each entrapped dye. The ion-pair formation between dye and surfactant causes a decline in electronic transition energy (ΔE T) when dye alkyl chains are smaller due to stabilization of both the ground and excited state. ΔE T values gradually increase with increase in dye hydrophobicity that hampers the electrostatic interaction with dialkylammonium moiety and consequently excited state stabilization is compromised. The average number of dye molecules trapped in a single micelle was also determined. The negative values of Gibbs free energy indicate that the dye entrapment within micelles is energetically favored. These findings have significance for developing functional materials with peculiar luminescent properties, especially for more effective probing of complex biological systems.

  2. Hydrophobic duck feathers and their simulation on textile substrates for water repellent treatment. (United States)

    Liu, Yuyang; Chen, Xianqiong; Xin, J H


    Inspired by the non-wetting phenomena of duck feathers, the water repellent property of duck feathers was studied at the nanoscale. The microstructures of the duck feather were investigated by a scanning electron microscope (SEM) imaging method through a step-by-step magnifying procedure. The SEM results show that duck feathers have a multi-scale structure and that this multi-scale structure as well as the preening oil are responsible for their super hydrophobic behavior. The microstructures of the duck feather were simulated on textile substrates using the biopolymer chitosan as building blocks through a novel surface solution precipitation (SSP) method, and then the textile substrates were further modified with a silicone compound to achieve low surface energy. The resultant textiles exhibit super water repellent properties, thus providing a simple bionic way to create super hydrophobic surfaces on soft substrates using flexible material as building blocks.

  3. Ultra lightweight PMMA-based composite plates with robust super-hydrophobic surfaces. (United States)

    Pareo, Paola; De Gregorio, Gian Luca; Manca, Michele; Pianesi, Maria Savina; De Marco, Luisa; Cavallaro, Francesco; Mari, Margherita; Pappadà, Silvio; Ciccarella, Giuseppe; Gigli, Giuseppe


    Extremely lightweight plates made of an engineered PMMA-based composite material loaded with hollow glass micro-sized spheres, nano-sized silica particles and aluminum hydroxide prismatic micro-flakes were realized by cast molding. Their interesting bulk mechanical properties were combined to properly tailored surface topography compatible with the achievement of a superhydrophobic behavior after the deposition of a specifically designed hydrophobic coating. With this aim, we synthesized two different species of fluoromethacrylic polymers functionalized with methoxysilane anchoring groups to be covalently grafted onto the surface protruding inorganic fillers. By modulating the feed composition of the reacting monomers, it was possible to combine the hydrophobic character of the polymer with an high adhesion strength to the substrate and hence to maximize both the water contact angle (up to 157°) and the durability of the easy-to-clean effect (up to 2000 h long outdoor exposure). Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Hydrophobic perfluoropolymer thin-film encapsulation for enhanced stability of inverted polymer solar cells (United States)

    Kim, Jae-Hyun; Park, Sung Kyu; Lee, Jung-Wook; Yoo, Byungwook; Lee, Jin-Kyun; Kim, Yong-Hoon


    We report hydrophobic perfluoropolymer thin-film encapsulation for enhancing the air ambient stability of inverted polymer solar cells (PSCs). Using a perfluoropolymer, poly(perfluorodecylmethacrylate) (PFDMA), as an encapsulation material, an orthogonal process that enables a solution-processing of encapsulation polymers to be coated directly on the inverted PSCs without damaging the underlying organic components is possible. Particularly, with PFDMA encapsulation, the air ambient stability was significantly enhanced, showing only an efficiency reduction of 23.3% after 456 hours of air exposure. The enhanced device stability can be attributed to the hydrophobic property of the PFDMA surface, which suppresses the transmission of air ambient gas molecules into the solar cells. Thus, the PFDMA coating can be beneficial in achieving high-stability organic electronics by using an easy-to-use route.

  5. Hydrophobic and porous cellulose nanofibrous screen for efficient particulate matter (PM2.5) blocking (United States)

    Chen, Liping; Guo, Yi; Peng, Xinsheng


    Particulate matter (PM2.5) pollution in air seriously affects public health. However, both bulk thickness and the accumulation of PM particles typically lead to a quick decline in the air permeability and large pressure drops of the conventional air clean membranes. In this work, we choose cellulose nanofibers (CNFs, a low cost, biodegradable and sustainable material) to form a hydrophobic and porous CNF thin layer on a stainless steel screen (300 mesh with pore size of 48 µm) through a simple filtration-assisted gelation process and subsequent polydimethylsiloxane modification. The prepared hydrophobic CNFs/stainless steel screen demonstrates highly efficient PM2.5 blocking based on size-sieving effect, fast air permeability and long-term durability under natural ventilation conditions in the relative humidity range from 45% to 93%. This technique holds great potential for indoor PM2.5 blocking under natural ventilation conditions.

  6. Mussel-inspired hydrophobic coatings for water-repellent textiles and oil removal. (United States)

    García, Beatríz; Saiz-Poseu, Javier; Gras-Charles, Roser; Hernando, Jordi; Alibés, Ramon; Novio, Fernando; Sedó, Josep; Busqué, Félix; Ruiz-Molina, Daniel


    A series of catechol derivatives with a different number of linear alkyl chain substituents, and different length, have been shown to polymerize in the presence of aqueous ammonia and air, yielding hydrophobic coatings that present the ability to provide robust and efficient water repellency on weaved textiles, including hydrophilic cotton. The polymerization strategy presented exemplifies an alternative route to established melanin- and polydopamine-like functional coatings, affording designs in which all catechol (adhesive) moieties support specific functional side chains for maximization of the desired (hydrophobic) functionality. The coatings obtained proved effective in the transformation of polyester and cotton weaves, as well as filter paper, into reusable water-repellent, oil-absorbent materials capable of retaining roughly double their weight in model compounds (n-tetradecane and olive oil), as well as of separating water/oil mixtures by simple filtration.

  7. Highly dealuminated Y zeolite as efficient adsorbent for the hydrophobic fraction from wastewater treatment plants effluents. (United States)

    Navalon, Sergio; Alvaro, Mercedes; Garcia, Hermenegildo


    In this work we report that highly dealuminated zeolite Y is a hydrophobic material that is able to remove selectively fatty acids and hydrocarbon compounds from the effluent of an urban wastewater treatment plant (UWTP). This adsorbent capability of zeolite Y could lead to an improved quality of UWTP effluents. Typical domestic wastewaters contain detergents, soaps and surfactants that are only partially removed in conventional UWTP. In the present work using an effluent from a UWTP located at Ribarroja del Turia (Valencia, Spain) containing 10 ppm of total organic carbon, we have been able to retain by adsorption on the dealuminated Y zeolite up to 16 and 60% of the organic matter of the effluent at pH values 7.2 and 4, respectively. Characterization of the adsorbed organic matter by Fourier transformed infrared (FT-IR), (1)H NMR and GC-MS after derivatization has shown that the zeolite adsorbs selectively the hydrophobic compounds of the effluent.

  8. Engineering Hydrophobic Organosilica Nanoparticle-Doped Nanofibers for Enhanced and Fouling Resistant Membrane Distillation

    KAUST Repository

    Hammami, Mohamed Amen


    Engineering and scaling-up new materials for better water desalination are imperative to find alternative fresh water sources to meet future demands. Herein, the fabrication of hydrophobic poly(ether imide) composite nanofiber membranes doped with novel ethylene-pentafluorophenylene-based periodic mesoporous organosilica nanoparticles is reported for enhanced and fouling resistant membrane distillation. Novel organosilica nanoparticles were homogeneously incorporated into electrospun nanofiber membranes depicting a proportional increase of hydrophobicity to the particle contents. Direct contact membrane distillation experiments on the organosilica-doped membrane with only 5% doping showed an increase of flux of 140% compared to commercial membranes. The high porosity of organosilica nanoparticles was further utilized to load the eugenol antimicrobial agent which produced a dramatic enhancement of the antibiofouling properties of the membrane of 70% after 24 h.

  9. Hydrophobically-modified chitosan foam: description and hemostatic efficacy. (United States)

    Dowling, Matthew B; Smith, William; Balogh, Peter; Duggan, Michael J; MacIntire, Ian C; Harris, Erica; Mesar, Tomaz; Raghavan, Srinivasa R; King, David R


    Trauma represents a significant public health burden, and hemorrhage alone is responsible for 40% of deaths within the first 24 h after injury. Noncompressible hemorrhage accounts for the majority of hemorrhage-related deaths. Thus, materials which can arrest bleeding rapidly are necessary for improved clinical outcomes. This preliminary study evaluated several self-expanding hydrophobically modified chitosan (HM-CS) foams to determine their efficacy on a noncompressible severe liver injury under resuscitation. Six HM-CS foam formulations (HM-CS1, HM-CS2, HM-CS3, HM-CS4, HM-CS5, and HM-CS6) of different graft types and densities were synthesized, characterized, and packaged into spray canisters using dimethyl ether as the propellant. Expansion profiles of the foams were evaluated in bench testing. Foams were then evaluated in vitro, interaction with blood cells was determined via microscopy, and cytotoxicity was assessed via live-dead cell assay on MCF7 breast cancer cells. For in vivo evaluation, rats underwent a 14 ± 3% hepatectomy. The animals were treated with either: (1) an HM-CS foam formulation, (2) CS foam, and (3) no treatment (NT). All animals were resuscitated with lactated Ringer solution. Survival, total blood loss, mean arterial pressures (MAP), and resuscitation volume were recorded for 60 min. Microscopy showed blood cells immobilizing into colonies within tight groups of adjacent foam bubbles. HM-CS foam did not display any toxic effects in vitro on MCF7 cells over a 72 h period studied. Application of HM-CS foam after hepatectomy decreased total blood loss (29.3 ± 7.8 mL/kg in HM-CS5 group versus 90.9 ± 20.3 mL/kg in the control group; P <0.001) and improved survival from 0% in controls to 100% in the HM-CS5 group (P <0.001). In this model of severe liver injury, spraying HM-CS foams directly on the injured liver surface decreased blood loss and increased survival. HM-CS formulations with the highest levels of hydrophobic modification (HM

  10. The electrical conductance growth of a metallic granular packing (United States)

    Jakšić, Zorica M.; Cvetković, Milica; Šćepanović, Julija R.; Lončarević, Ivana; Budinski-Petković, Ljuba; Vrhovac, Slobodan B.


    We report on measurements of the electrical conductivity on a two-dimensional packing of metallic disks when a stable current of 1 mA flows through the system. At low applied currents, the conductance σ is found to increase by a pattern σ( t) = σ ∞ - Δσ E α [ - ( t/ τ) α ], where E α denotes the Mittag-Leffler function of order α ∈ (0,1). By changing the inclination angle θ of the granular bed from horizontal, we have studied the impact of the effective gravitational acceleration g e ff = gsin θ on the relaxation features of the conductance σ( t). The characteristic timescale τ is found to grow when effective gravity g e ff decreases. By changing both the distance between the electrodes and the number of grains in the packing, we have shown that the long term resistance decay observed in the experiment is related to local micro-contacts rearrangements at each disk. By focusing on the electro-mechanical processes that allow both creation and breakdown of micro-contacts between two disks, we present an approach to granular conduction based on subordination of stochastic processes. In order to imitate, in a very simplified way, the conduction dynamics of granular material at low currents, we impose that the micro-contacts at the interface switch stochastically between two possible states, "on" and "off", characterizing the conductivity of the micro-contact. We assume that the time intervals between the consecutive changes of state are governed by a certain waiting-time distribution. It is demonstrated how the microscopic random dynamics regarding the micro-contacts leads to the macroscopic observation of slow conductance growth, described by an exact fractional kinetic equations.

  11. Low density gravel substitute gravel pack in Marlim

    Energy Technology Data Exchange (ETDEWEB)

    Albino, E.


    Successful gravel pack completion means optimization of production. This has been PETROBRAS` task regarding completion of the giant Marlim field. Significant improvement have been noticed recently with the introduction of techniques such as horizontal drilling, frac pack and low density gravel substitute gravel pack. This paper discusses the introduction and results of the system, its advantages and trends since this technique can become an excellent alternative when a more aggressive technique is no economical. (author). 5 refs., 4 figs.

  12. RF plasma based selective modification of hydrophilic regions on super hydrophobic surface

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jaehyun; Hwang, Sangyeon; Cho, Dae-Hyun [Department of Mechanical Engineering, Sungkyunkwan University, Suwon 16419 (Korea, Republic of); Hong, Jungwoo [Department of Mechanical Engineering, Graduate of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141 (Korea, Republic of); Shin, Jennifer H., E-mail: [Department of Mechanical Engineering, Graduate of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141 (Korea, Republic of); Byun, Doyoung, E-mail: [Department of Mechanical Engineering, Sungkyunkwan University, Suwon 16419 (Korea, Republic of)


    Highlights: • Simple and amenable reforming method for a substrate with disparate patterns of hydrophilic dots on super-hydrophobic surfaces is proposed. • Wettability characteristics and modification mechanism for the surfaces are conducted and revealed through SEM, AFM, WSI, and SIMS. • Several representative materials for various applications are successfully deposited. - Abstract: Selective modification and regional alterations of the surface property have gained a great deal of attention to many engineers. In this paper, we present a simple, a cost-effective, and amendable reforming method for disparate patterns of hydrophilic regions on super-hydrophobic surfaces. Uniform super-hydrophobic layer (Contact angle; CA > 150°, root mean square (RMS) roughness ∼0.28 nm) can be formed using the atmospheric radio frequency (RF) plasma on top of the selective hydrophilic (CA ∼ 70°, RMS roughness ∼0.34 nm) patterns imprinted by electrohydrodynamic (EHD) jet printing technology with polar alcohols (butyl carbitol or ethanol). The wettability of the modified surface was investigated qualitatively utilizing scanning electron microscopy (SEM), atomic force microscopy (AFM), and wavelength scanning interferometer (WSI). Secondary ion mass spectroscopy (SIMS) analysis showed that the alcohol addiction reaction changed the types of radicals on the super-hydrophobic surface. The wettability was found to depend sensitively on chemical radicals on the surface, not on surface morphology (particle size and surface roughness). Furthermore, three different kinds of representative hydrophilic samples (polystyrene nano-particle aqueous solution, Salmonella bacteria medium, and poly(3,4-ethylenediocythiophene) ink) were tested for uniform deposition onto the desired hydrophilic regions. This simple strategy would have broad applications in various research fields that require selective deposition of target materials.

  13. Hydrophobic and hydrophilic interactions in aqueous mixtures of alcohols at a hydrophobic surface. (United States)

    Ballal, Deepti; Chapman, Walter G


    Aqueous solutions of alcohols are interesting because of their anomalous behavior that is believed to be due to the molecular structuring of water and alcohol around each other in solution. The interfacial structuring and properties are significant for application in alcohol purification processes and biomolecular structure. Here we study aqueous mixtures of short alcohols (methanol, ethanol, 1-propanol, and 2-propanol) at a hydrophobic surface using interfacial statistical associating fluid theory which is a perturbation density functional theory. The addition of a small amount of alcohol decreases the interfacial tension of water drastically. This trend in interfacial tension can be explained by the structure of water and alcohol next to the surface. The hydrophobic group of an added alcohol preferentially goes to the surface preserving the structure of water in the bulk. For a given bulk alcohol concentration, water mixed with the different alcohols has different interfacial tensions with propanol having a lower interfacial tension than methanol and ethanol. 2-propanol is not as effective in decreasing the interfacial tension as 1-propanol because it partitions poorly to the surface due to its larger excluded volume. But for a given surface alcohol mole fraction, all the alcohol mixtures give similar values for interfacial tension. For separation of alcohol from water, methods that take advantage of the high surface mole fraction of alcohol have advantages compared to separation using the vapor in equilibrium with a water-alcohol liquid.

  14. Automated Hydrophobic Interaction Chromatography Column Selection for Use in Protein Purification (United States)

    Murphy, Patrick J. M.; Stone, Orrin J.; Anderson, Michelle E.


    In contrast to other chromatographic methods for purifying proteins (e.g. gel filtration, affinity, and ion exchange), hydrophobic interaction chromatography (HIC) commonly requires experimental determination (referred to as screening or "scouting") in order to select the most suitable chromatographic medium for purifying a given protein 1. The method presented here describes an automated approach to scouting for an optimal HIC media to be used in protein purification. HIC separates proteins and other biomolecules from a crude lysate based on differences in hydrophobicity. Similar to affinity chromatography (AC) and ion exchange chromatography (IEX), HIC is capable of concentrating the protein of interest as it progresses through the chromatographic process. Proteins best suited for purification by HIC include those with hydrophobic surface regions and able to withstand exposure to salt concentrations in excess of 2 M ammonium sulfate ((NH4)2SO4). HIC is often chosen as a purification method for proteins lacking an affinity tag, and thus unsuitable for AC, and when IEX fails to provide adequate purification. Hydrophobic moieties on the protein surface temporarily bind to a nonpolar ligand coupled to an inert, immobile matrix. The interaction between protein and ligand are highly dependent on the salt concentration of the buffer flowing through the chromatography column, with high ionic concentrations strengthening the protein-ligand interaction and making the protein immobile (i.e. bound inside the column) 2. As salt concentrations decrease, the protein-ligand interaction dissipates, the protein again becomes mobile and elutes from the column. Several HIC media are commercially available in pre-packed columns, each containing one of several hydrophobic ligands (e.g. S-butyl, butyl, octyl, and phenyl) cross-linked at varying densities to agarose beads of a specific diameter 3. Automated column scouting allows for an efficient approach for determining which HIC media

  15. Packed bed carburization of tantalum and tantalum alloy (United States)

    Lopez, P.C.; Rodriguez, P.J.; Pereyra, R.A.


    Packed bed carburization of a tantalum or tantalum alloy object is disclosed. A method for producing corrosion-resistant tantalum or tantalum alloy objects is described. The method includes the steps of placing the object in contact with a carburizing pack, heating the packed object in vacuum furnace to a temperature whereby carbon from the pack diffuses into the object forming grains with tantalum carbide along the grain boundaries, and etching the surface of the carburized object. This latter step removes tantalum carbides from the surface of the carburized tantalum object while leaving the tantalum carbide along the grain boundaries. 4 figs.

  16. A novel reactor configuration for packed bed chemical-looping combustion of syngas

    Energy Technology Data Exchange (ETDEWEB)

    Hamers, H.P.; Gallucci, F.; Van Sint Annaland, M. [Multiphase Reactor Group, Chemical Process Intensification, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Cobden, P.D. [Energy Research Centre of the Netherlands (ECN), P.O. Box 1, 1755 ZG Petten (Netherlands); Kimball, E. [TNO Gas Treatment, P.O. Box 6000, 2600 JA Delft (Netherlands)


    This study reports on the application of chemical looping combustion (CLC) in pressurized packed bed reactors using syngas as a fuel. High pressure operation of CLC in packed bed has a different set of challenges in terms of material properties, cycle and reactor design compared to fluidized bed operation. However, high pressure operation allows the use of inherently more efficient power cycles than low pressure fluidized bed solutions. This paper quantifies the challenges in high pressure operation and introduces a novel reactor concept with which those challenges can be addressed. Continuous cyclic operation of a packed bed CLC system is simulated in a 1D numerical reactor model. Importantly, it is demonstrated that the temperature profiles that can occur in a packed bed reactor as a result of the different process steps do not accumulate, and have a negligible effect on the overall performance of the system. Moreover, it has been shown that an even higher energy efficiency can be achieved by feeding the syngas from the opposite direction during the reduction step (i.e. countercurrent operation). Unfortunately, in this configuration mode, more severe temperature fluctuations occur in the reactor exhaust, which is disadvantageous for the operation of a downstream gas turbine. Finally, a novel reactor configuration is introduced in which the desired temperature rise for obtained hot pressured air suitable for a gas turbine is obtained by carrying out the process with two packed bed reactor in series (two-stage CLC). This is shown to be a good alternative to the single bed configuration, and has the added advantage of decreasing the demands on both the oxygen carrier and the reactor materials and design specification.

  17. Fluoroalkyl and Alkyl Chains Have Similar Hydrophobicities in Binding to the “Hydrophobic Wall” of Carbonic Anhydrase

    Energy Technology Data Exchange (ETDEWEB)

    J Mecinovic; P Snyder; K Mirica; S Bai; E Mack; R Kwant; D Moustakas; A Heroux; G Whitesides


    The hydrophobic effect, the free-energetically favorable association of nonpolar solutes in water, makes a dominant contribution to binding of many systems of ligands and proteins. The objective of this study was to examine the hydrophobic effect in biomolecular recognition using two chemically different but structurally similar hydrophobic groups, aliphatic hydrocarbons and aliphatic fluorocarbons, and to determine whether the hydrophobicity of the two groups could be distinguished by thermodynamic and biostructural analysis. This paper uses isothermal titration calorimetry (ITC) to examine the thermodynamics of binding of benzenesulfonamides substituted in the para position with alkyl and fluoroalkyl chains (H{sub 2}NSO{sub 2}C{sub 6}H{sub 4}-CONHCH{sub 2}(CX{sub 2}){sub n}CX{sub 3}, n = 0-4, X = H, F) to human carbonic anhydrase II (HCA II). Both alkyl and fluoroalkyl substituents contribute favorably to the enthalpy and the entropy of binding; these contributions increase as the length of chain of the hydrophobic substituent increases. Crystallography of the protein-ligand complexes indicates that the benzenesulfonamide groups of all ligands examined bind with similar geometry, that the tail groups associate with the hydrophobic wall of HCA II (which is made up of the side chains of residues Phe131, Val135, Pro202, and Leu204), and that the structure of the protein is indistinguishable for all but one of the complexes (the longest member of the fluoroalkyl series). Analysis of the thermodynamics of binding as a function of structure is compatible with the hypothesis that hydrophobic binding of both alkyl and fluoroalkyl chains to hydrophobic surface of carbonic anhydrase is due primarily to the release of nonoptimally hydrogen-bonded water molecules that hydrate the binding cavity (including the hydrophobic wall) of HCA II and to the release of water molecules that surround the hydrophobic chain of the ligands. This study defines the balance of enthalpic and

  18. The friction property of super-hydrophobic cotton textiles (United States)

    Su, Changhong; Li, Jun


    Two kinds of super-hydrophobic cotton textiles were prepared via dip-coating cotton textiles with nano-silica suspensions, and the cotton textiles exhibits high contact angle more than 160° and low sliding angle lower than 4°. A friction method was used to evaluate the durability of the as-prepared super-hydrophobic cotton textiles, the results shows that one of the as-prepared super-hydrophobic cottons exhibits better stability property against friction, and its contact angle remained higher than 150° and sliding angle remained lower than 15° after 1000 times friction. SEM analysis shows the reduction of hydrophobic property was resulted from the damage of surface structure during friction cycle.

  19. Hydrophobization of dense and fine concrete by polysulfide solutions

    Directory of Open Access Journals (Sweden)

    MASSALIMOV Ismail Alexandrovich


    Full Text Available The results of research on hydrophobic impregnation of dense concrete with composition «Aquastat» designed for manufacture of road and airfield plates are presented. It was found that after having been treated with waterrepellent agent the concrete sample is resistant to wetting, i.e. it gets hydrophobic properties. At the same time the water absorption of the samples treated for 24 hours at atmospheric pressure is reduced in three times, and soaked for 0.5 hours under vacuum decreases 5.5 times. It was revealed that the hydrophobic properties of fine-grained concrete impregnated with «Aquastat» may be at the same level of those of dense concrete based on coarse filler. Substantially increased hydrophobic properties of dense concrete (more than 5 times allow authors to forecast twice increased service life of road and airfield plates treated by «Aquastat» composition.

  20. Impact of Hydrophobic Pollutants' Behavior on Occupational and Environmental Health

    Directory of Open Access Journals (Sweden)

    Ijeoma Kanu


    Full Text Available This paper reviews the influence of hydrophobic pollutant behavior on environmental hazards and risks. The definition and examples of hydrophobic pollutants are given as a guide to better understand the sources of release and the media of dispersion in the environment. The properties and behavior of hydrophobic pollutants are described and their influence on environmental hazard and risk is reviewed and evaluated. The overall outcome of the assessment and evaluation showed that all hydrophobic pollutants are hazardous and risky to all organisms, including man. Their risk effects are due to their inherent persistence, bioaccumulation potential, environmental mobility, and reactivity. Their hazardous effects on organisms occur at varying spatial and temporal degrees of emissions, toxicities, exposures, and concentrations.

  1. Are N-methyl groups of Tetramethylurea (TMU) Hydrophobic? A ...

    Indian Academy of Sciences (India)

    methyl groups of Tetramethylurea (TMU) Hydrophobic? A composition and temperature-dependent fluorescence spectroscopic investigation of TMU/water binary mixtures. SANDIPA INDRA RANJIT BISWAS. Regular Article Volume 128 Issue 5 ...

  2. Quantifying effective slip length over micropatterned hydrophobic surfaces

    NARCIS (Netherlands)

    Tsai, Peichun Amy; Peters, A.M.; Pirat, C.; Wessling, Matthias; Lammertink, Rob G.H.; Lohse, Detlef


    We employ microparticle image velocimetry to investigate laminar microflows in hydrophobic microstructured channels, in particular the slip length. These microchannels consist of longitudinal microgrooves, which can trap air and prompt a shear-free boundary condition and thus slippage enhancement.

  3. Extended surfaces modulate hydrophobic interactions of neighboring solutes. (United States)

    Patel, Amish J; Varilly, Patrick; Jamadagni, Sumanth N; Acharya, Hari; Garde, Shekhar; Chandler, David


    Interfaces are a most common motif in complex systems. To understand how the presence of interfaces affects hydrophobic phenomena, we use molecular simulations and theory to study hydration of solutes at interfaces. The solutes range in size from subnanometer to a few nanometers. The interfaces are self-assembled monolayers with a range of chemistries, from hydrophilic to hydrophobic. We show that the driving force for assembly in the vicinity of a hydrophobic surface is weaker than that in bulk water and decreases with increasing temperature, in contrast to that in the bulk. We explain these distinct features in terms of an interplay between interfacial fluctuations and excluded volume effects--the physics encoded in Lum-Chandler-Weeks theory [Lum K, Chandler D, Weeks JD (1999) J Phys Chem B 103:4570-4577]. Our results suggest a catalytic role for hydrophobic interfaces in the unfolding of proteins, for example, in the interior of chaperonins and in amyloid formation.

  4. Encapsulation and retention of chelated-copper inside hydrophobic nanoparticles

    DEFF Research Database (Denmark)

    Hervella, Pablo; Ortiz, Elisa Parra; Needham, David


    that our endogenous-inspired nanoparticle strategies for imaging and therapeutics are focused on encapsulating and retaining imaging ions such as copper inside novel hydrophobic nanoparticles. In this paper, we describe a new approach to label the core of hydrophobic nanoparticles composed of Glyceryl...... Trioleate (Triolein) with copper using the hydrophobic chelator Octaethyl porphyrin (OEP). RESEARCH PLAN AND METHODS: The research plan for this study was to (1) Formulate nanoparticles and control nanoparticle size using a modification of the solvent injection technique, named fast ethanol injection; (2...... to nanoparticles was >95% at low OEP-Cu concentrations. In the absence of OEP, copper was not detected in nanoparticles demonstrating the role of the hydrophobic chelator OEP in the encapsulation of the otherwise water-soluble copper inside lipid nanoparticles. (4) The in vitro retention upon incubation at 37°C...

  5. Hydrogels for Hydrophobic Drug Delivery. Classification, Synthesis and Applications

    Directory of Open Access Journals (Sweden)

    Eneko Larrañeta


    Full Text Available Hydrogels have been shown to be very useful in the field of drug delivery due to their high biocompatibility and ability to sustain delivery. Therefore, the tuning of their properties should be the focus of study to optimise their potential. Hydrogels have been generally limited to the delivery of hydrophilic drugs. However, as many of the new drugs coming to market are hydrophobic in nature, new approaches for integrating hydrophobic drugs into hydrogels should be developed. This article discusses the possible new ways to incorporate hydrophobic drugs within hydrogel structures that have been developed through research. This review describes hydrogel-based systems for hydrophobic compound delivery included in the literature. The section covers all the main types of hydrogels, including physical hydrogels and chemical hydrogels. Additionally, reported applications of these hydrogels are described in the subsequent sections.

  6. Hydrophobicity – Shake Flasks, Protein Folding and Drug Discovery (United States)

    Sarkar, Aurijit; Kellogg, Glen E.


    Hydrophobic interactions are some of the most important interactions in nature. They are the primary driving force in a number of phenomena. This is mostly an entropic effect and can account for a number of biophysical events such as protein-protein or protein-ligand binding that are of immense importance in drug design. The earliest studies on this phenomenon can be dated back to the end of the 19th century when Meyer and Overton independently correlated the hydrophobic nature of gases to their anesthetic potency. Since then, significant progress has been made in this realm of science. This review briefly traces the history of hydrophobicity research along with the theoretical estimation of partition coefficients. Finally, the application of hydrophobicity estimation methods in the field of drug design and protein folding is discussed. PMID:19929828

  7. Using crosslinkable diacetylene phospholipids to construct two-dimensional packed beds in supported lipid bilayer separation platforms

    Directory of Open Access Journals (Sweden)

    Shu-Kai Hu, Sheng-Wen Hsiao, Hsun-Yen Mao, Ya-Ming Chen, Yung Chang and Ling Chao


    Full Text Available Separating and purifying cell membrane-associated biomolecules has been a challenge owing to their amphiphilic property. Taking these species out of their native lipid membrane environment usually results in biomolecule degradation. One of the new directions is to use supported lipid bilayer (SLB platforms to separate the membrane species while they are protected in their native environment. Here we used a type of crosslinkable diacetylene phospholipids, diynePC (1,2-bis(10,12-tricosadiynoyl-sn-glycero-3-phosphocholine, as a packed material to create a 'two-dimensional (2D packed bed' in a SLB platform. After the diynePC SLB is exposed to UV light, some of the diynePC lipids in the SLB can crosslink and the non-crosslinked monomer lipids can be washed away, leaving a 2D porous solid matrix. We incorporated the lipid vesicle deposition method with a microfluidic device to pattern the location of the packed-bed region and the feed region with species to be separated in a SLB platform. Our atomic force microscopy result shows that the nano-scaled structure density of the '2D packed bed' can be tuned by the UV dose applied to the diynePC membrane. When the model membrane biomolecules were forced to transport through the packed-bed region, their concentration front velocities were found to decrease linearly with the UV dose, indicating the successful creation of packed obstacles in these 2D lipid membrane separation platforms.

  8. Packing of ganglioside-phospholipid monolayers

    DEFF Research Database (Denmark)

    Majewski, J.; Kuhl, T.L.; Kjær, K.


    Using synchrotron grazing-incidence x-ray diffraction (GIXD) and reflectivity, the in-plane and out-of-plane structure of mixed ganglioside-phospholipid monolayers was investigated at the air-water interface. Mixed monolayers of 0, 5, 10, 20, and 100 mol% ganglioside GM, and the phospholipid...... dipaimitoylphosphatidylethanolamine (DPPE) were studied in the solid phase at 23 degreesC and a surface pressure of 45 mN/m. At these concentrations and conditions the two components do not phase-separate and no evidence for domain formation was observed. X-ray scattering measurements reveal that GM, is accommodated within the host...... polymer groups. Indeed, the lack of packing disruptions by the oligosaccharide groups indicates that protein-GM, interactions, including binding, insertion, chain fluidization, and domain formation (lipid rafts), can be studied in 2-D monolayers using scattering techniques....

  9. Slow creep in soft granular packings. (United States)

    Srivastava, Ishan; Fisher, Timothy S


    Transient creep mechanisms in soft granular packings are studied numerically using a constant pressure and constant stress simulation method. Rapid compression followed by slow dilation is predicted on the basis of a logarithmic creep phenomenon. Characteristic scales of creep strain and time exhibit a power-law dependence on jamming pressure, and they diverge at the jamming point. Microscopic analysis indicates the existence of a correlation between rheology and nonaffine fluctuations. Localized regions of large strain appear during creep and grow in magnitude and size at short times. At long times, the spatial structure of highly correlated local deformation becomes time-invariant. Finally, a microscale connection between local rheology and local fluctuations is demonstrated in the form of a linear scaling between granular fluidity and nonaffine velocity.

  10. School meal sociality or lunch pack individualism?

    DEFF Research Database (Denmark)

    Andersen, Sidse Schoubye; Holm, Lotte; Baarts, Charlotte


    the social life of a school class, and how these arrangements involve strategies of both inclusion and exclusion. Two types of school meals are compared in the intervention study: a hot meal based on Nordic ingredients and the normal Danish school meal arrangement in which children bring lunch packs......The present article specifies and broadens our understanding of the concept of commensality by investigating what it means to ‘share a meal’. The study utilizes a school meal intervention carried out in Denmark in 2011/2012. It shows how different types of school meal arrangement influence...... to school. The study discusses commensality by examining and comparing lunchtime interactions within the same group of children in the two contrasting meal situations. The results fail to confirm the conventional view that shared meals have greater social impacts and benefits than eating individualized...

  11. Scientific basis of a new method for hydrophobic modification of mineral binders using peat products

    Directory of Open Access Journals (Sweden)

    O. Misnikov


    Full Text Available This study deals with the issue of caking of mineral binding materials during storage and transportation. The author conducted a critical analysis of known methods for the protection of cement from exposure to moisture and water vapour. Common disadvantages of these methods are their low effectiveness and complexity of use in industrial and domestic environments. This article introduces a new method for hydrophobising construction materials using peat, which achieves high water repellency in the modified materials with relatively low expenditure on organic materials. The author proposes film coating of the mineral particles of dispersed hydrophilic materials as a protection mechanism against their undesirable exposure to moisture during storage. The insulating film consists of hydrophobic products (bitumens released during thermal decomposition of the organic matter in peat. The estimated thickness of the bitumen film is about 12 nm and it does not adversely affect the flow properties of the powder. A model of the formation of film coatings on mineral particles is provided and their elemental chemical composition is determined. It is shown experimentally that the modified hydrophobic cement is protected from exposure to liquid vapours, and optimal values of organic component concentrations in the dispersed mineral matter that do not reduce the strength of cement mortar are identified.

  12. Hydrogen Evolution on Hydrophobic Aligned Carbon Nanotube Arrays


    Misra, Abha; Giri, Jyotsnendu; Daraio, Chiara


    We investigate for the first time hydrophobic carbon nanotube-based electrochemical cells as an alternative solution to hydrogen sorting. We show that the electrically conducting surface of the nanotube arrays can be used as a cathode for hydrogen generation and absorption by electrolyzing water. We support our findings with Raman and gas chromatography measurements. These results suggest that carbon nanotube forests, presenting a unique combination of hydrophobicity and conductivity, are sui...


    Directory of Open Access Journals (Sweden)

    M.A.F. Melo


    Full Text Available This work deals with the use of carnauba wax as an expansion and hydrophobicity agent for vermiculite, to be utilized in the sorption process of oil in water. Evaluation of the system (oil-water-hydrophobic vermiculite submersion percentage was considered in assessing the performance of vermiculite in comparison to a Mexican turf. Carnauba wax seems to be more efficient in both fresh and salt waters.

  14. Surface Deposition and Phase Behavior of Oppositely Charged Polyion–Surfactant Ion Complexes. Delivery of Silicone Oil Emulsions to Hydrophobic and Hydrophilic Surfaces (United States)


    The adsorption from mixed polyelectrolyte–surfactant solutions at hydrophobized silica surfaces was investigated by in situ null-ellipsometry, and compared to similar measurements for hydrophilic silica surfaces. Three synthetic cationic copolymers of varying hydrophobicity and one cationic hydroxyethyl cellulose were compared in mixtures with the anionic surfactant sodium dodecylsulfate (SDS) in the absence or presence of a dilute silicone oil emulsion. The adsorption behavior was mapped while stepwise increasing the concentration of SDS to a polyelectrolyte solution of constant concentration. The effect on the deposition of dilution of the bulk solution in contact with the surface was also investigated by gradual replacement of the bulk solution with 1 mM aqueous NaCl. An adsorbed layer remained after complete exchange of the polyelectrolyte/surfactant solution for aqueous NaCl. In most cases, there was a codeposition of silicone oil droplets, if such droplets were present in the formulation before dilution. The overall features of the deposition were similar at hydrophobic and hydrophilic surfaces, but there were also notable differences. SDS molecules adsorbed selectively at the hydrophobized silica surface, but not at the hydrophilic silica, which influenced the coadsorption of the cationic polymers. The largest amount of deposited material after dilution was found for hydrophilic silica and for the least-hydrophobic cationic polymers. For the least-hydrophobic polyions, no significant codeposition of silicone oil was detected at hydrophobized silica after dilution if the initial SDS concentration was high. PMID:21667982

  15. Estimation of nitrogen volatilisation in the bedded-pack of dairy cow barns

    Directory of Open Access Journals (Sweden)

    Antonello Cannas


    Full Text Available The objective of the study was to measure N volatilisation (NVOL from bedded-pack dairy cow barns. Feed intake, milk production, bedding material used and meteorological variables were monitored in 3 dairy farms near the town of Arborea (39°46’26” N, 08°34’53” E, 7 m a.s.l. during one month for each season from summer 2007 to spring 2008. NVOL was measured in the interval between excretion and removal of bedded-packs from barn floors. NVOL was measured using the N (nitrogen to P (phosphorus ratio marker method, considering P as an internal non-volatile marker in milk and manure. Nitrogen and P excretion was estimated by nutrient balance as intake minus N and P excreted in milk. NVOL coefficient and bad-pack temperature were almost constant among seasons. The annual mean NVOL in bedded-pack barns was equal to 38.8% of excreted N. Accounting also for the NVOL that occurred in the concrete floor of the feeding and walking areas of the barns, NVOL was 40.7% of N excreted.

  16. Brittleness and Packing Density Effects on Blast-hole Cuttings Yield of Selected Rocks

    Directory of Open Access Journals (Sweden)

    B. Adebayo


    Full Text Available This paper evaluates brittleness and packing density to analysis their effects on blast-hole cutting yield for three selected rocks in Nigeria. Brittleness test (S20 was carried out in accordance with Norwegian Soil and Rock Engineering and the Brittleness Index (BI for the selected rocks were estimated. The packing density determined from the photomicrograph of the rock samples. The grain size of 45 blast-holes drill cuttings collected from three selected while drilling of these rocks were determined using standard method of America Society for Testing and Materials (ASTM D 2487. The brittleness values are 50%, 44% and 42% for micro granite, porphyritic granite and medium biotite granite respectively. The result of BI varied from 10.32 – 11.59 and they are rated as moderately brittle rocks. The values of packing density varied from 92.20 – 94.55%, 91.00 -92.96% and 92.92 – 94.96% for all the rocks. The maximum weights of blast-hole particle size retained at 75 µm are 106.00g, 103.28 g and 99.76 g for medium biotite granite, micro granite and porhyritic granite respectively. Packing density values have correlation to some extent with (S20 values hence, this influence the yield of blast-hole cuttings as drilling progresses. The minimum weight of blast-hole cuttings particle size retained at 150 µm agrees with brittleness index classification for micro granite.


    Directory of Open Access Journals (Sweden)

    Raúl Alfonso Rodríguez


    Full Text Available This paper develops a method for the recovery of shaft of centrifugal pumps worn area packings. The procedure was applied to the recovery pump aluminum sulfate used in the process of demineralization of water in ¨Carlos M. de Céspedes¨ Thermoelectric Plant of Cienfuegos. This equipment was damaged due to wear on the product shaft more than two decades of operation. To this end a new scheme for the Analysis of shaft packings considered as additional elastic supports is used. Using this scheme the reaction on shaft packing is calculated. Processing the results of the literature for soft packings equation correlation between the coefficient of kinetic friction and the shaft, which enabled calculation of the moment of friction, find the minimum pressure between the sleeve and the shaft so it does not slide was obtained. Dimensions and material of the sleeve is first found the maximum pressure setting selected and verified that it can be carried by the cap. Reduced resistance for the placement of sleeve and found to be burdened evaluated shaft.

  18. Self-assembly of uniform polyhedral silver nanocrystals into densest packings and exotic superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Henzie, Joel [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Grünwald, Michael [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Widmer-Cooper, Asaph [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Science Division; Univ. of Sydney, NSW (Australia). School of Chemistry; Geissler, Phillip L. [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Science Division; Yang, Peidong [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Science Division; Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Engineering


    Understanding how polyhedra pack into extended arrangements is integral to the design and discovery of crystalline materials at all length scales. Much progress has been made in enumerating and characterizing the packing of polyhedral shapes, and the self-assembly of polyhedral nanocrystals into ordered superstructures. However, directing the self-assembly of polyhedral nanocrystals into densest packings requires precise control of particle shape, polydispersity,interactions and driving forces. Here we show with experiment and computer simulation that a range of nanoscale Ag polyhedra can self-assemble into their conjectured densest packings. When passivated with adsorbing polymer, the polyhedra behave as quasi-hard particles and assemble into millimetre-sized three-dimensional supercrystals by sedimentation.We also show, by inducing depletion attraction through excess polymer in solution, that octahedra form an exotic superstructure with complex helical motifs rather than the densest Minkowski lattice. Such large-scale Ag supercrystals may facilitate the design of scalable three-dimensional plasmonic metamaterials for sensing, nanophotonics, and photocatalysis.

  19. Hydrogels with smart systems for delivery of hydrophobic drugs. (United States)

    Gu, Dunyin; O'Connor, Andrea J; G H Qiao, Greg; Ladewig, Katharina


    Smart hydrogel systems present opportunities to not only provide hydrophobic molecule encapsulation capability but to also respond to specific delivery routes. Areas covered: An overview of the design principles, preparation methods and applications of hydrogel systems for delivery of hydrophobic drugs is given. It begins with a summary of the advantages of hydrogels as delivery vehicles over other approaches, particularly macromolecular nanocarriers, before proceeding to address the design and preparation strategies and chemistry involved, with a particular focus on the introduction of hydrophobic domains into (naturally) hydrophilic hydrogels. Finally, the applications in different delivery routes are discussed. Expert opinion: Modifications to conventional hydrogels can endow them with the capability to carry hydrophobic drugs but other functions as well, such as the improved mechanical stability, which is important for long-term in vivo residence and/or self-healing properties useful for injectable delivery pathways. These modifications harness hydrophobic-hydrophobic forces, physical interactions and inclusion complexes. The lack of in-depth understanding of these interactions, currently limits more delicate and application-oriented designs. Increased efforts are needed in (i) understanding the interplay of gel formation and simultaneous drug loading; (ii) improving hydrogel systems with respect to their biosafety; and (iii) control over release mechanism and profile.

  20. Condensation Dynamics on Mimicked Metal Matrix Hydrophobic Nanoparticle-Composites (United States)

    Damle, Viraj; Sun, Xiaoda; Rykaczewski, Konrad


    Use of hydrophobic surfaces promotes condensation in the dropwise mode, which is significantly more efficient than the common filmwise mode. However, limited longevity of hydrophobic surface modifiers has prevented their wide spread use in industry. Recently, metal matrix composites (MMCs) having microscale hydrophobic heterogeneities dispersed in hydrophilic metal matrix have been proposed as durable and self-healing alternative to hydrophobic surface coatings interacting with deposited water droplets. While dispersion of hydrophobic microparticles in MMC is likely to lead to surface flooding during condensation, the effect of dispersion of hydrophobic nanoparticles (HNPs) with size comparable to water nuclei critical radii and spacing is not obvious. To this end, we fabricated highly ordered arrays of Teflon nanospheres on silicon substrates that mimic the top surface of the MMCs with dispersed HNPs. We used light and electron microscopy to observe breath figures resulting from condensation on these surfaces at varied degrees of subcooling. Here, we discuss the relation between the droplet size distribution, Teflon nanosphere diameter and spacing, and condensation mode. KR acknowledges startup funding from ASU.

  1. Hydrophobic collapse of trigger factor monomer in solution.

    Directory of Open Access Journals (Sweden)

    Kushagra Singhal

    Full Text Available Trigger factor (TF is a chaperone, found in bacterial cells and chloroplasts, that interacts with nascent polypeptide chains to suppress aggregation. While its crystal structure has been resolved, the solution structure and dynamics are largely unknown. We performed multiple molecular dynamics simulations on Trigger factor in solution, and show that its tertiary domains display collective motions hinged about inter-domain linkers with minimal or no loss in secondary structure. Moreover, we find that isolated TF typically adopts a collapsed state, with the formation of domain pairs. This collapse of TF in solution is induced by hydrophobic interactions and stabilised by hydrophilic contacts. To determine the nature of the domain interactions, we analysed the hydrophobicity of the domain surfaces by using the hydrophobic probe method of Acharya et al., as the standard hydrophobicity scales predictions are limited due to the complex environment. We find that the formation of domain pairs changes the hydrophobic map of TF, making the N-terminal and arm2 domain pair more hydrophilic and the head and arm1 domain pair more hydrophobic. These insights into the dynamics and interactions of the TF domains are important to eventually understand chaperone-substrate interactions and chaperone function.

  2. Aggregation of amyloidogenic peptides near hydrophobic and hydrophilic surfaces. (United States)

    Brovchenko, Ivan; Singh, Gurpreet; Winter, Roland


    The general effect of surface hydrophobicity/hydrophilicity on the aggregation of peptides is studied by simulations of oversaturated aqueous solutions of hydrophobic and hydrophilic amyloidogenic peptides. Peptide aggregation was studied in bulk solution, in solutions confined between hydrophobic boundaries (smooth planar paraffin-like surfaces and liquid-vapor interfaces) and in solutions confined between hydrophilic surfaces (smooth planar silica-like surfaces). Aggregation of hydrophobic peptides strongly enhances due to the confinement between hydrophobic surfaces with all peptides adsorbed at the boundaries and aligned predominantly parallel to them. In the other three cases considered, the peptides are repelled from the walls and do not reveal orientational ordering with respect to the surface. The degree of peptide aggregation in these cases is only slightly affected by the confinement (it is enhanced for hydrophobic peptides and decreased for hydrophilic peptides). Our results show that even a single environmental factor such as water-mediated peptide-surface interaction has a drastic effect on the degree and character of peptide aggregation. A wide diversity of possible scenarios can be expected when specific peptide-surface interactions are additionally taken into account.

  3. Sound Packing DNA: packing open circular DNA with low-intensity ultrasound (United States)

    Park, Donghee; Jung, Bong-Kwang; Park, Hyunjin; Lee, Hyungbeen; Lee, Gyudo; Park, Jingam; Shin, Unchul; Won, Jong Ho; Jo, Yong Jun; Chang, Jin Woo; Lee, Sangwoo; Yoon, Daesung; Seo, Jongbum; Kim, Chul-Woo


    Supercoiling DNA (folding DNA into a more compact molecule) from open circular forms requires significant bending energy. The double helix is coiled into a higher order helix form; thus it occupies a smaller footprint. Compact packing of DNA is essential to improve the efficiency of gene delivery, which has broad implications in biology and pharmaceutical research. Here we show that low-intensity pulsed ultrasound can pack open circular DNA into supercoil form. Plasmid DNA subjected to 5.4 mW/cm2 intensity ultrasound showed significant (p-values DNA without exposure to ultrasound. Radiation force induced from ultrasound and dragging force from the fluid are believed to be the main factors that cause supercoiling. This study provides the first evidence to show that low-intensity ultrasound can directly alter DNA topology. We anticipate our results to be a starting point for improved non-viral gene delivery.

  4. Preparative gel permeation chromatographic separation of solvent refined coal. [Tetrahydrofuran and chloroform; evaluation of 3 column packings

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, W.M.; Wooton, D.L.; Dorn, H.C.; Taylor, L.T.


    A preparative quantitative separation of THF- and CHCl/sub 3/-soluble solvent refined coal (Pittsburgh No. 8) has been demonstrated employing gel permeation chromatographic techniques utilizing three column packings: a styrene--divinyl benzene packing (Bio-Beads S-X4), a cross-linked poly(N-acryloylmorpholine) polymer (Enzacryl Gel K-1), and a modified alkylated dextran (Sephadex LH-20). Each packing material is evaluated based on the extent and time of separation and the cost of materials. The percent recovery in the Bio-Bead case is greater than 95 percent. Average molecular weights via vapor phase osmometry on the four sized fractions of THF-soluble SRC from Bio-Beads suggests that a separation according to molecular weight has been achieved. The description of a short tapered glass column to economically carry out these preparative separations is described.

  5. Percolation and jamming in random heterogeneous materials

    NARCIS (Netherlands)

    Kyrylyuk, A.V.; Wouterse, A.; Philipse, A.P.


    Dense packings of particles of different size and shape are simulated by the mechanical contraction method (MCM). The effect of particle shape and particle size disparity on the packing density and micro-structure of twocomponent composite materials with competing length scales is investigated. We

  6. Blister packing of copper hydroxide and titania nanoparticles on graphene and its recycling. (United States)

    Sridhar, Vadahanambi; Gangaraju, Deepa; Chun, Ho-Hwan; Park, Hyun


    Metal nanoparticles anchored on a graphene substrate find many applications such as sensors, catalysts, lithium ion batteries, etc. However, to date, graphene-metal nanohybrids have been synthesized by either covalent or ionic interactions between the graphene substrate and the metal nanoparticles. In this manuscript, we report a green and facile method to "bubble pack" metal nanoparticles on a graphene substrate by a simple process utilizing eco-friendly ionic liquids in conjunction with microwave heating. Copper nanoparticles bubble packed on graphene showed enhanced glucose sensing when compared to covalently bonded copper/graphene hybrids. Titania nanoparticles bubble packed on graphene when applied as anode materials in lithium ion batteries exhibited two times more lithium ion retention when compared to covalently bonded titania/graphene hybrids. "End of life" disposal of nanomaterials into the environment is a growing area of concern in recent days. One way of dealing with this problem is to extend the life cycle of nanomaterials by reusing the nanomaterials in multiple applications. In this report, we also show the recyclability of our novel bubble packaging material, by etching out the metal nanoparticles resulting in a unique 3D hierarchical graphene nanocup decorated graphene. The applicability of this recycled material in super capacitors is also reported.

  7. Evaluation of high packing density powder X-ray screens by Monte Carlo methods (United States)

    Liaparinos, P.; Kandarakis, I.; Cavouras, D.; Kalivas, N.; Delis, H.; Panayiotakis, G.


    Phosphor materials are employed in intensifying screens of both digital and conventional X-ray imaging detectors. High packing density powder screens have been developed (e.g. screens in ceramic form) exhibiting high-resolution and light emission properties, and thus contributing to improved image transfer characteristics and higher radiation to light conversion efficiency. For the present study, a custom Monte Carlo simulation program was used in order to examine the performance of ceramic powder screens, under various radiographic conditions. The model was developed using Mie scattering theory for the description of light interactions, based on the physical characteristics (e.g. complex refractive index, light wavelength) of the phosphor material. Monte Carlo simulations were carried out assuming: (a) X-ray photon energy ranging from 18 up to 49 keV, (b) Gd 2O 2S:Tb phosphor material with packing density of 70% and grain size of 7 μm and (c) phosphor thickness ranging between 30 and 70 mg/cm 2. The variation of the Modulation Transfer Function (MTF) and the Luminescence Efficiency (LE) with respect to the X-ray energy and the phosphor thickness was evaluated. Both aforementioned imaging characteristics were shown to take high values at 49 keV X-ray energy and 70 mg/cm 2 phosphor thickness. It was found that high packing density screens may be appropriate for use in medical radiographic systems.

  8. Measured Black Carbon Deposition on the Sierra Nevada Snow Pack and Implication for Snow Pack Retreat

    Energy Technology Data Exchange (ETDEWEB)

    Hadley, O.L.; Corrigan, C.E.; Kirchstetter, T.W.; Cliff, S.S.; Ramanathan, V.


    Modeling studies show that the darkening of snow and ice by black carbon deposition is a major factor for the rapid disappearance of arctic sea ice, mountain glaciers and snow packs. This study provides one of the first direct measurements for the efficient removal of black carbon from the atmosphere by snow and its subsequent deposition to the snow packs of California. The early melting of the snow packs in the Sierras is one of the contributing factors to the severe water problems in California. BC concentrations in falling snow were measured at two mountain locations and in rain at a coastal site. All three stations reveal large BC concentrations in precipitation, ranging from 1.7 ng/g to 12.9 ng/g. The BC concentrations in the air after the snow fall were negligible suggesting an extremely efficient removal of BC by snow. The data suggest that below cloud scavenging, rather than ice nuclei, was the dominant source of BC in the snow. A five-year comparison of BC, dust, and total fine aerosol mass concentrations at multiple sites reveals that the measurements made at the sampling sites were representative of large scale deposition in the Sierra Nevada. The relative concentration of iron and calcium in the mountain aerosol indicates that one-quarter to one-third of the BC may have been transported from Asia.

  9. New series of paper pack vending machines; Paper pack jido hanbaiki no shin series

    Energy Technology Data Exchange (ETDEWEB)

    Ohashi, M. [Fuji Denki Reiki Co. Ltd., Tokyo (Japan); Umino, S. [Fuji Electric Co. Ltd., Tokyo (Japan)


    This paper presents series of paper pack vending machines. These machines may be broadly classified into those of cold drinks and of hot and cold drinks depending on the storage temperature of products. The former is the machine for cooling dairy products at 10{degree}C with a combined stacking by direct-stacked racks and chain-multiracks. The latter is provided with divided storing chambers with each chamber selectively cooled or heated. Products in the hot chamber are canned coffee and the like set at 55{degree}C. The temperature control is performed by a microcomputer. The chain-multiracks are provided with advantages such as capability of handling various kinds of container shapes, storing drinks and foods vertically, replacing products by the change of a shelf attachment with one operation, and storing one liter packs by setting pair columns. The direct-stacked racks are provided with advantages such as versatility of handling various kinds of containers and miniaturization of the mechanism other than the storage part. The installation space was reduced by devising the opening and closing of the door. The control part is capable of setting temperatures differently for cans and paper packs. 7 figs., 1 tab.

  10. Measured black carbon deposition on the Sierra Nevada snow pack and implication for snow pack retreat

    Directory of Open Access Journals (Sweden)

    O. L. Hadley


    Full Text Available Modeling studies show that the darkening of snow and ice by black carbon deposition is a major factor for the rapid disappearance of arctic sea ice, mountain glaciers and snow packs. This study provides one of the first direct measurements for the efficient removal of black carbon from the atmosphere by snow and its subsequent deposition to the snow packs of California. The early melting of the snow packs in the Sierras is one of the contributing factors to the severe water problems in California. BC concentrations in falling snow were measured at two mountain locations and in rain at a coastal site. All three stations reveal large BC concentrations in precipitation, ranging from 1.7 ng/g to 12.9 ng/g. The BC concentrations in the air after the snow fall were negligible suggesting an extremely efficient removal of BC by snow. The data suggest that below cloud scavenging, rather than ice nuclei, was the dominant source of BC in the snow. A five-year comparison of BC, dust, and total fine aerosol mass concentrations at multiple sites reveals that the measurements made at the sampling sites were representative of large scale deposition in the Sierra Nevada. The relative concentration of iron and calcium in the mountain aerosol indicates that one-quarter to one-third of the BC may have been transported from Asia.

  11. Microplastics as a vector of hydrophobic contaminants: Importance of hydrophobic additives. (United States)

    Kwon, Jung-Hwan; Chang, Sein; Hong, Sang Hee; Shim, Won Joon


    Despite a recent boom in research on the environmental fate, distribution, and harmful effects of chemical substances associated with marine plastic debris, no consensus has been reached on whether chemicals originating from microplastics cause serious environmental harm. For the risk assessment of chemical contaminants associated with microplastics, it would be useful to group organic chemicals into 2 categories: additives and nonadditives. Whereas plastic particles are not likely to be diffuse sources of chemicals that are not intentionally added to plastic products, continuous leaching of additives would result in higher concentrations, at least at a local scale. Unlike plasticizers and flame retardants, which have been relatively well investigated, antioxidants and photostabilizers have been rarely studied, even though many of them are highly hydrophobic and are not readily biodegradable. More research on the fate and effects of chemicals via microplastics should focus on those additives. Integr Environ Assess Manag 2017;13:494-499. © 2017 SETAC. © 2017 SETAC.

  12. RF plasma based selective modification of hydrophilic regions on super hydrophobic surface (United States)

    Lee, Jaehyun; Hwang, Sangyeon; Cho, Dae-Hyun; Hong, Jungwoo; Shin, Jennifer H.; Byun, Doyoung


    Selective modification and regional alterations of the surface property have gained a great deal of attention to many engineers. In this paper, we present a simple, a cost-effective, and amendable reforming method for disparate patterns of hydrophilic regions on super-hydrophobic surfaces. Uniform super-hydrophobic layer (Contact angle; CA > 150°, root mean square (RMS) roughness ∼0.28 nm) can be formed using the atmospheric radio frequency (RF) plasma on top of the selective hydrophilic (CA ∼ 70°, RMS roughness ∼0.34 nm) patterns imprinted by electrohydrodynamic (EHD) jet printing technology with polar alcohols (butyl carbitol or ethanol). The wettability of the modified surface was investigated qualitatively utilizing scanning electron microscopy (SEM), atomic force microscopy (AFM), and wavelength scanning interferometer (WSI). Secondary ion mass spectroscopy (SIMS) analysis showed that the alcohol addiction reaction changed the types of radicals on the super-hydrophobic surface. The wettability was found to depend sensitively on chemical radicals on the surface, not on surface morphology (particle size and surface roughness). Furthermore, three different kinds of representative hydrophilic samples (polystyrene nano-particle aqueous solution, Salmonella bacteria medium, and poly(3,4-ethylenediocythiophene) ink) were tested for uniform deposition onto the desired hydrophilic regions. This simple strategy would have broad applications in various research fields that require selective deposition of target materials.

  13. Tough Supramolecular Hydrogel Based on Strong Hydrophobic Interactions in a Multiblock Segmented Copolymer (United States)


    We report the preparation and structural and mechanical characterization of a tough supramolecular hydrogel, based exclusively on hydrophobic association. The system consists of a multiblock, segmented copolymer of hydrophilic poly(ethylene glycol) (PEG) and hydrophobic dimer fatty acid (DFA) building blocks. A series of copolymers containing 2K, 4K, and 8K PEG were prepared. Upon swelling in water, a network is formed by self-assembly of hydrophobic DFA units in micellar domains, which act as stable physical cross-link points. The resulting hydrogels are noneroding and contain 75–92 wt % of water at swelling equilibrium. Small-angle neutron scattering (SANS) measurements showed that the aggregation number of micelles ranges from 2 × 102 to 6 × 102 DFA units, increasing with PEG molecular weight. Mechanical characterization indicated that the hydrogel containing PEG 2000 is mechanically very stable and tough, possessing a tensile toughness of 4.12 MJ/m3. The high toughness, processability, and ease of preparation make these hydrogels very attractive for applications where mechanical stability and load bearing features of soft materials are required. PMID:28469284

  14. Complexity in Surfaces of Densest Packings for Families of Polyhedra

    Directory of Open Access Journals (Sweden)

    Elizabeth R. Chen


    Full Text Available Packings of hard polyhedra have been studied for centuries due to their mathematical aesthetic and more recently for their applications in fields such as nanoscience, granular and colloidal matter, and biology. In all these fields, particle shape is important for structure and properties, especially upon crowding. Here, we explore packing as a function of shape. By combining simulations and analytic calculations, we study three two-parameter families of hard polyhedra and report an extensive and systematic analysis of the densest known packings of more than 55 000 convex shapes. The three families have the symmetries of triangle groups (icosahedral, octahedral, tetrahedral and interpolate between various symmetric solids (Platonic, Archimedean, Catalan. We find optimal (maximum packing-density surfaces that reveal unexpected richness and complexity, containing as many as 132 different structures within a single family. Our results demonstrate the importance of thinking about shape not as a static property of an object, in the context of packings, but rather as but one point in a higher-dimensional shape space whose neighbors in that space may have identical or markedly different packings. Finally, we present and interpret our packing results in a consistent and generally applicable way by proposing a method to distinguish regions of packings and classify types of transitions between them.

  15. Hydrodynamics of multi-phase packed bed micro-reactors

    NARCIS (Netherlands)

    Márquez Luzardo, N.M.


    Why to use packed bed micro-reactors for catalyst testing? Miniaturized packed bed reactors have a large surface-to-volume ratio at the reactor and particle level that favors the heat- and mass-transfer processes at all scales (intra-particle, inter-phase and inter-particle or reactor level). If the

  16. The sintering behavior of close-packed spheres

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Tikare, V.; Frandsen, Henrik Lund


    The sintering behavior of close-packed spheres is investigated using a numerical model. The investigated systems are the body-centered cubic (bcc), face-centered cubic (fcc) and hexagonal close-packed spheres (hcp). The sintering behavior is found to be ideal, with no grain growth until full...

  17. The performance of structured packings in trickle-bed reactors.

    NARCIS (Netherlands)

    Frank, M.J.W.; Frank, M.J.W.; Kuipers, J.A.M.; Versteeg, Geert; van Swaaij, Willibrordus Petrus Maria


    An experimental study was carried out to investigate whether the use of structured packings might improve the mass transfer characteristics and the catalyst effectiveness of a trickle-bed reactor. Therefore, the performances of a structured packing, consisting of KATAPAK elements, and a dumped

  18. The Performance of Structured Packings in Trickle-Bed Reactors

    NARCIS (Netherlands)

    Frank, M.J.W.; Kuipers, J.A.M.; Versteeg, G.F.; Swaaij, W.P.M. van


    An experimental study was carried out to investigate whether the use of structured packings might improve the mass transfer characteristics and the catalyst effectiveness of a trickle-bed reactor. Therefore, the performances of a structured packing, consisting of KATAPAK elements, and a dumped

  19. Evaluation of microbial quality of selected blister-packed ...

    African Journals Online (AJOL)

    Ten brands of blister-packed paracetamol tablet and twenty brands of paracetamol syrup marketed in Nigeria were evaluated for their microbial quality. While no microbial contaminant was isolated from all blistered-packed paracetamol tablets, ten of syrups were contaminated with organisms such as Escherichia coli, ...

  20. demonstrating close-packing of atoms using spherical bubble gums

    African Journals Online (AJOL)


    chemistry and junior inorganic chemistry courses. However, the subject of three dimen- sional close-packing of atoms has always been difficult for students to understand. In particular, students find it difficult to visualize the packing of atoms in different layers. They cannot clearly identify tetrahedral and octahedral holes, and.

  1. CoolPack – Simulation tools for refrigeration systems

    DEFF Research Database (Denmark)

    Jakobsen, Arne; Rasmussen, Bjarne D.; Andersen, Simon Engedal


    from Users without access to the Internet can contact Team CoolPack by using the address stated in the last paragraph.The purpose of this article is twofold: Introduction to the use of CoolPack and presentation of some of the related technical issues of modelling and layout...

  2. 76 FR 251 - Country of Origin Labeling of Packed Honey (United States)


    ... Service 7 CFR Part 52 RIN 0581-AC89 Country of Origin Labeling of Packed Honey AGENCY: Agricultural..., establishing new regulations addressing country of origin labeling for packed honey bearing any official USDA... service for honey if country of origin labeling requirements are not met for packages of honey containing...

  3. Characteristics of illegal and legal cigarette packs sold in Guatemala. (United States)

    Arevalo, Rodrigo; Corral, Juan E; Monzon, Diego; Yoon, Mira; Barnoya, Joaquin


    Guatemala, as a party to the Framework Convention on Tobacco Control (FCTC), is required to regulate cigarette packaging and labeling and eliminate illicit tobacco trade. Current packaging and labeling characteristics (of legal and illegal cigarettes) and their compliance with the FCTC is unknown. We sought to analyze package and label characteristics of illegal and legal cigarettes sold in Guatemala. We visited the 22 largest traditional markets in the country to purchase illegal cigarettes. All brands registered on tobacco industry websites were purchased as legal cigarettes. Analysis compared labeling characteristics of illegal and legal packs. Most (95%) markets and street vendors sold illegal cigarettes; 104 packs were purchased (79 illegal and 25 legal). Ten percent of illegal and none of the legal packs had misleading terms. Half of the illegal packs had a warning label covering 26 to 50% of the pack surface. All legal packs had a label covering 25% of the surface. Illegal packs were more likely to have information on constituents and emissions (85% vs. 45%, p illegal nor legal cigarette packs comply with FCTC labeling mandates. Urgent implementation and enforcement of the FCTC is necessary to halt the tobacco epidemic.

  4. Nutritional Contents of Lunch Packs of Primary School Children in ...

    African Journals Online (AJOL)

    Background: Lunch packs play a significant role in the nutritional status and academic performance of school children. Available data show a high prevalence of malnutrition among school‑age children. Aims: The aim of this study is to document the nutritional contents of lunch packs of primary school children in Nnewi, ...

  5. demonstrating close-packing of atoms using spherical bubble gums

    African Journals Online (AJOL)


    ABSTRACT: In this paper, the use of spherical bubble gums (Gum Balls) to demonstrate the close-packing of atoms and ions is presented. Spherical bubble gums having distinctive colours were used to illustrate the different layers in variety of crystalline packing and the formation of tetrahedral and octahedral holes.

  6. Nutritional Contents of Lunch Packs of Primary School Children in ...

    African Journals Online (AJOL)

    range of nutrients, a child needs to consume a good variety of foods from different food groups, every day and in the right proportions.[6] Packing adequate meals including fruits and. Nutritional Contents of Lunch Packs of Primary. School Children in Nnewi, Nigeria. Ugochukwu EF, Onubogu CU, Edokwe ES, Okeke KN.

  7. Effects on Packed Cell Volume and Parasitic Worm Load from ...

    African Journals Online (AJOL)

    One of the consequences of parasitic worm infestation in children is anaemia which is objectively measured by estimating the packed cell volume. This study carried out through four months was to examine the effects, (on packed cell volume and parasitic worm load) of de-worming pupils of a primary school in Rivers State.

  8. Improved Erythrocyte Osmotic Fragility and Packed Cell Volume ...

    African Journals Online (AJOL)

    Improved Erythrocyte Osmotic Fragility and Packed Cell Volume following administration of Aloe barbadensis Juice Extract in Rats. ... Abstract. Aloe barbadensis is a popular house plant that has a long history of a multipurpose folk remedy. ... Keywords: osmotic fragility, packed cell volume, haemoglobin, Aloe vera ...

  9. Experimental validation of packed bed chemical-looping combustion

    NARCIS (Netherlands)

    Noorman, S.; van Sint Annaland, M.; Kuipers, J.A.M.


    Chemical-looping combustion has emerged as a promising alternative technology, intrinsically integrating CO2 capture in power production. A novel reactor concept based on dynamically operated packed beds has been proposed [Noorman, S., van Sint Annaland, M., Kuipers, J.A.M., 2007. Packed bed reactor

  10. An efficient block-discriminant identification of packed malware

    Indian Academy of Sciences (India)

    Extracting original payload by executing packed file in virtual environment requires resources and is prone to ... To create these environments, numerous virtual or sandboxing frameworks are .... ESCAPE utilizes blockwise entropy values and PEAL uses learning algorithm for discriminat- ing packed or native binaries.

  11. Numerical optimization method for packing regular convex polygons (United States)

    Galiev, Sh. I.; Lisafina, M. S.


    An algorithm is presented for the approximate solution of the problem of packing regular convex polygons in a given closed bounded domain G so as to maximize the total area of the packed figures. On G a grid is constructed whose nodes generate a finite set W on G, and the centers of the figures to be packed can be placed only at some points of W. The problem of packing these figures with centers in W is reduced to a 0-1 linear programming problem. A two-stage algorithm for solving the resulting problems is proposed. The algorithm finds packings of the indicated figures in an arbitrary closed bounded domain on the plane. Numerical results are presented that demonstrate the effectiveness of the method.

  12. Effect of adhesive hydrophobicity on microtensile bond strength of low-shrinkage silorane resin to dentin

    Directory of Open Access Journals (Sweden)

    So-Yeun Cho


    Full Text Available Objectives The purpose of this study was to evaluate µTBS (microtensile bond strength of current dentin bonding adhesives which have different hydrophobicity with low-shrinkage silorane resin. Materials and Methods Thirty-six human third molars were used. Middle dentin was exposed. The teeth were randomly assigned to nine experimental groups: Silorane self-etch adhesives (SS, SS + phosphoric acid etching (SS + pa, Adper easy bond (AE, AE + Silorane system bonding (AE + SSb, Clearfil SE bond (CSE, CSE + SSb, All-Bond 2 (AB2, AB2 + SSb, All-Bond 3 (AB3. After adhesive's were applied, the clinical crowns were restored with Filtek LS (3M ESPE. The 0.8 mm × 0.8 mm sticks were submitted to a tensile load using a Micro Tensile Tester (Bisco Inc.. Water sorption was measured to estimate hydrophobicity adhesives. Results µTBS of silorane resin to 5 adhesives: SS, 23.2 MPa; CSE, 19.4 MPa; AB3, 30.3 MPa; AB2 and AE, no bond. Additional layering of SSb: CSE + SSb, 26.2 MPa; AB2 + SSb, 33.9 MPa; AE + SSb, no bond. High value of µTBS was related to cohesive failure. SS showed the lowest water sorption. AE showed the highest solubility. Conclusions The hydrophobicity of adhesive increased, and silorane resin bond-strength was also increased. Additional hydrophobic adhesive layer did not increase the bond-strength to silorane resin except AB2 + SSb. All-Bond 3 showed similar µTBS & water sorption with SS. By these facts, we could reach a conclusion that All-Bond 3 is a competitive adhesive which can replace the Silorane adhesive system


    Directory of Open Access Journals (Sweden)

    AILENI Raluca Maria


    Full Text Available This paper presents aspects regarding life cycle inventory (LCI of the classical hydrophobization process used in textiles finishing. According to the ISO 14040-14044 stardards used for determine the framework for conducting an LCA (life cycle assessment, there are 4 steps for obtaining an LCA – scope definition, LCI, LCA impact, LC (life cycle interpretation. In our work, we analized warming impact generated by gases, water footprint and energy impact. For analyzed sample (bbc 100%, treated with NUVATTC (based on fluorocarbon for obtaining hydrophobic effect, was analyzed the LCI and the process tree. The goal was to obtain the environment impact level for classical hydrophobization based on fluorocarbon. The research methodology consisted in collecting technical input and output data and using the SimaPro software for generating the LCI. We obtained the input data (raw material, energy, chemical substances and water consumption by direct measurements on machinery, device logs and specifications of the equipment (technical books and processes. The output data (waste energy, water and chemicals were obtained using statistics, internet databases and SimaPro software. The environmental impact categories identification (carginogenic, inorganic compounds upon the breath, climate change, radiation, ozone layer, Eco-toxicity, land use, minerals and fossil fuels was done by using the method ECO indicator 99. This study shows that the process of classic hydrophobization has a negative impact on significantly on climate change, fossil fuels, ozone layer and effects of inorganic compounds upon the respiration, and all this is the consequence of the chemicals, based on fluorocarbon, use.

  14. A multi-staining chip using hydrophobic valves for exfoliative cytology in cancer (United States)

    Lee, Tae Hee; Bu, Jiyoon; Moon, Jung Eun; Kim, Young Jun; Kang, Yoon-Tae; Cho, Young-Ho; Kim, In Sik


    Exfoliative cytology is a highly established technique for the diagnosis of tumors. Various microfluidic devices have been developed to minimize the sample numbers by conjugating multiple antibodies in a single sample. However, the previous multi-staining devices require complex control lines and valves operated by external power sources, to deliver multiple antibodies separately for a single sample. In addition, most of these devices are composed of hydrophobic materials, causing unreliable results due to the non-specific binding of antibodies. Here, we present a multi-staining chip using hydrophobic valves, which is formed by the partial treatment of 2-hydroxyethyl methacrylate (HEMA). Our chip consists of a circular chamber, divided into six equal fan-shaped regions. Switchable injection ports are located at the center of the chamber and at the middle of the arc of each fan-shaped zone. Thus, our device is beneficial for minimizing the control lines, since pre-treatment solutions flow from the center to outer ports, while six different antibodies are introduced oppositely from the outer ports. Furthermore, hydrophobic narrow channels, connecting the central region and each of the six fan-shaped zones, are closed by capillary effect, thus preventing the fluidic mixing without external power sources. Meanwhile, HEMA treatment on the exterior region results in hydrophobic-to-hydrophilic transition and prevents the non-specific binding of antibodies. For the application, we measured the expression of six different antibodies in a single sample using our device. The expression levels of each antibody highly matched the conventional immunocytochemistry results. Our device enables cancer screening with a small number of antibodies for a single sample.

  15. Single water entropy: hydrophobic crossover and application to drug binding. (United States)

    Sasikala, Wilbee D; Mukherjee, Arnab


    Entropy of water plays an important role in both chemical and biological processes e.g. hydrophobic effect, molecular recognition etc. Here we use a new approach to calculate translational and rotational entropy of the individual water molecules around different hydrophobic and charged solutes. We show that for small hydrophobic solutes, the translational and rotational entropies of each water molecule increase as a function of its distance from the solute reaching finally to a constant bulk value. As the size of the solute increases (0.746 nm), the behavior of the translational entropy is opposite; water molecules closest to the solute have higher entropy that reduces with distance from the solute. This indicates that there is a crossover in translational entropy of water molecules around hydrophobic solutes from negative to positive values as the size of the solute is increased. Rotational entropy of water molecules around hydrophobic solutes for all sizes increases with distance from the solute, indicating the absence of crossover in rotational entropy. This makes the crossover in total entropy (translation + rotation) of water molecule happen at much larger size (>1.5 nm) for hydrophobic solutes. Translational entropy of single water molecule scales logarithmically (Str(QH) = C + kB ln V), with the volume V obtained from the ellipsoid of inertia. We further discuss the origin of higher entropy of water around water and show the possibility of recovering the entropy loss of some hypothetical solutes. The results obtained are helpful to understand water entropy behavior around various hydrophobic and charged environments within biomolecules. Finally, we show how our approach can be used to calculate the entropy of the individual water molecules in a protein cavity that may be replaced during ligand binding.

  16. Comparison of two polarity measurements of hydrophobic organic matter for the evaluation of water treatment processes: XAD resin and PRAM. (United States)

    Philibert, Marc; Rosario-Ortiz, Fernando; Suffet, Mel


    Dissolved organic matter (DOM) is a mixture of thousands of organic molecules wide-ranging in molecular weight, polarity and physicochemical properties. DOM is responsible for multiple water treatment issues such as trihalomethane (THM) formation potential and membrane fouling. Two methods of evaluating the polarity of DOM are being used for water treatment application: a serial XAD resin adsorption method at acid pH and the polarity rapid assessment method (PRAM) by parallel solid phase extraction (SPE) cartridges at natural pH. These two methods have been described by their authors as able to define a hydrophobic fraction though they do so by sorption onto different types of material at different pHs. The first part of this study compared the PRAM and XAD methods and showed that the hydrophobic fractions defined by the two approaches were not correlated. This result highlighted the difficulties in defining fractions as 'hydrophobic material'. It appeared that the sorbents for XAD-8 (an acrylic polymer containing oxygen) at pH water sources. This evaluation showed that the smaller molecular weight fraction of DOM (<1 kDa) had a higher percentage of hydrophobic character and that the fluorescence-defined aromatic protein fraction was the most hydrophilic.

  17. Influence of growth phase on bacterial deposition: interaction mechanisms in packed-bed column and radial stagnation point flow systems. (United States)

    Walker, Sharon L; Redman, Jeremy A; Elimelech, Menachem


    The influence of bacterial growth stage on cell deposition kinetics has been examined using a mutant of Escherichia coli K12. Two experimental techniques--a packed-bed column and a radial stagnation point flow (RSPF) system--were employed to determine bacterial deposition rates onto quartz surfaces over a wide range of solution ionic strengths. Stationary-phase cells were found to be more adhesive than mid-exponential phase cells in both experimental systems. The divergence in deposition behavior was notably more pronounced in the RSPF than in the packed-bed system. For instance, in the RSPF system, the deposition rate of the stationary-phase cells at 0.03 M ionic strength was 14 times greater than that of the mid-exponential cells. The divergence in the packed-bed system was most significant at 0.01 M, where the deposition rate for the stationary-phase cells was nearly 4 times greater than for the mid-exponential cells. To explain the observed adhesion behavior, the stationary and mid-exponential bacterial cells were characterized for their size, surface charge density, electrophoretic mobility, viability, and hydrophobicity. On the basis of this analysis, it is suggested that the stationary cells have a more heterogeneous distribution of charged functional groups on the bacterial surface than the mid-exponential cells, which results in higher deposition kinetics. Furthermore, because the RSPF system enumerates only bacterial cells retained in primary minima, whereas the packed column captures mostly cells deposited in secondary minima, the difference in the stationary and mid-exponential cell deposition kinetics is much more pronounced in the RSPF system.

  18. Steric stabilization of nonaqueous silicon slips. I - Control of particle agglomeration and packing. II - Pressure casting of powder compacts (United States)

    Kerkar, Awdhoot V.; Henderson, Robert J. M.; Feke, Donald L.


    The application of steric stabilization to control particle agglomeration and packing of silicon powder in benzene and trichloroethylene is reported. The results provide useful guidelines for controlling unfavorable particle-particle interactions during nonaqueous processing of silicon-based ceramic materials. The application of steric stabilization to the control and improvement of green processing of nonaqueous silicon slips in pressure consolidation is also demonstrated.

  19. Packing schemes of cavities in selected clathrasils and zeolites and the analogous packings of atoms in crystal structures

    DEFF Research Database (Denmark)

    Hem, Caroline Piper; Makovicky, Emil; Balic Zunic, Tonci


    Sizes of cavities and their packing schemes in selected zeolites and clathrasils were studied by means of least squares fitting of circumscribed spheres to them. Resulting packing of spheres of different diameters was analyzed by the coordinates of their centers, their volumes and sphericity......, and interpreted by comparison with analogous packings of atoms in inorganic compounds and alloys. The topology is described qualitatively as “negative” structures formed by the cavities. Melanophlogite and dodecasils 3C and 1H are all clathrasils with isolated cavities. They all have pentagonal dodecahedral [512......] cages, associated with other cavity types. The packing of cavities in melanophlogite is analogous to the packing of atoms in the structure of Cr3Si, where the Cr atoms form icosahedra around the Si sites. Dodecasil 3C has a cubic arrangement of [512] cavities, which is described as ABC stacking...

  20. Influence of hydrophobicity distribution of particle mixtures on emulsion stabilization. (United States)

    Chen, Qiang; Stricek, Igor; Gray, Murray R; Liu, Qi


    Whilst emulsions stabilized by uniform particles are well established, the emulsification behavior of heterogeneous mixtures of particles with varying hydrophobicity is rarely examined. Consequently, the influence of the distribution of particle hydrophobicity on oil-water emulsion stabilization is poorly understood. In the present work, the wettability of the bitumen froth fine solids from Alberta oil sands was studied by film flotation and toluene-water emulsification tests, before and after a hydrothermal treatment at 300-420°C. This approach provided a series of populations of particles with different distributions of hydrophobicity. The initial fine particles in the bitumen froth had a critical surface tension ranging from 26 to 56mN/m, with a mean value of 39mN/m. Hydrothermal treatment at 300-420°C progressively shifted the hydrophobicity distribution of the fine particles, resulting in a lower mean critical surface tension and a narrower critical surface tension range. The emulsifying capacity of the fine particle mixtures, as indicated by the volume of the produced toluene-water emulsions, was unrelated to the mean critical surface tension. Instead, emulsification depended on the proportion of a specific sub-fraction of particles with a critical surface tension of 27-30mN/m. This sub-fraction of particles, with intermediate hydrophobicity, dominated the emulsification behavior of the particle mixtures. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Influence of hydrophobicity on the chemical treatments of graphene (United States)

    Rai, Krishna Bahadur; Khadka, Ishwor Bahadur; Kim, Eun Hye; Ahn, Sung Joon; Kim, Hyun Woo; Ahn, Joung Real


    The defect-free transfer of graphene grown by using chemical vapor deposition is essential for its applications to electronic devices. For the reduction of inevitable chemical residues, such as polar molecules and ionized impurities resulting from the transfer process, a hydrophobic polydimethyl-siloxane (PDMS) film was coated on a SiO2/Si wafer. The hydrophobic PDMS film resulted in fewer defects in graphene in comparison to a bare SiO2/Si wafer, as measured with Raman spectroscopy. We also studied the influence of the hydrophobic PDMS film on the chemical doping of graphene. Here, nitric acid (HNO3) was used to make p-type graphene. When graphene was transferred onto a SiO2/Si wafer coated with the hydrophobic PDMS film, fewer defects, compared to those in graphene transferred onto a bare SiO2/Si wafer, were created in grapheme by HNO3 as measured with Raman spectroscopy. The experiments suggest that when graphene is transferred onto a hydrophobic film, the number of defects created by chemical molecules can be reduced.

  2. Characterization method of hydrophobic anti-icing coatings. (United States)

    Morita, Katsuaki; Sakaue, Hirotaka


    For anti-icing, supercooled water should be removed before frozen onto the contact surface. We use a hydrophobic coating for anti-icing and introduce the static- and dynamic-evaluation methods. The methods describe the contact surface between the hydrophobic surface and a supercooled-water droplet. The former is based on the contact angle, and the latter is based on the sliding angle. The temperature factor is included in these models to evaluate the hydrophobic coating under the supercooled conditions. Four hydrophobic coatings are experimentally evaluated based on the static- and dynamic evaluation methods: C1-C3 (commercial fluorocarbon coatings), and Jaxa coating (original fluorocarbon coating). These are evaluated under the supercooled conditions of -10 to 0 °C. The static-evaluation shows variations in the temperature. However, change in the contact angle by the temperature is relatively small compared to that of the sliding angle for the dynamic evaluation. Only C3 and Jaxa coatings are tolerant to the sliding angle under the supercooled conditions tested. The dynamic evaluation shows that even if the coating is hydrophobic, the dynamic evaluation should be included to understand the characteristic of removal for a supercooled-water droplet.

  3. Autoactivation of blood factor XII at hydrophilic and hydrophobic surfaces. (United States)

    Zhuo, Rui; Siedlecki, Christopher A; Vogler, Erwin A


    Contact activation of blood factor XII (FXII, Hageman factor) in neat-buffer solution is shown not to be specific for anionic hydrophilic procoagulants as proposed by the accepted biochemistry of surface activation. Rather, FXII activation in the presence of plasma proteins leads to an apparent specificity for hydrophilic surfaces that is actually due to a relative diminution of the FXII-->FXIIa reaction at hydrophobic surfaces. FXII activation in neat-buffer solution was effectively instantaneous upon contact with either hydrophilic (fully water-wettable clean glass) or hydrophobic (poorly water-wettable silanized glass) procoagulant particles, with greater FXIIa yield obtained by activation with hydrophobic procoagulants. In sharp contrast, both activation rate and yield was found to be significantly attenuated at hydrophobic surfaces in the presence of plasma proteins. Putative FXIIa produced by surface activation with both hydrophilic and hydrophobic procoagulants was shown to hydrolyze blood factor XI (FXI) to the activated form FXIa (FXIFXIIa-->FXIa) that causes FXI-deficient plasma to rapidly coagulate.

  4. Titration of hydrophobic polyelectrolytes using Monte Carlo simulations (United States)

    Ulrich, Serge; Laguecir, Abohachem; Stoll, Serge


    The conformation and titration curves of weak (or annealed) hydrophobic polyelectrolytes have been examined using Monte Carlo simulations with screened Coulomb potentials in the grand canonical ensemble. The influence of the ionic concentration pH and presence of hydrophobic interactions has been systematically investigated. A large number of conformations such as extended, pearl-necklace, cigar-shape, and collapsed structures resulting from the subtle balance of short-range hydrophobic attractive interactions and long-range electrostatic repulsive interactions between the monomers have been observed. Titration curves were calculated by adjusting the pH-pK0 values (pK0 represents the intrinsic dissociation constant of an isolated monomer) and then calculating the ionization degree α of the polyelectrolyte. Important transitions related to cascades of conformational changes were observed in the titration curves, mainly at low ionic concentration and with the presence of strong hydrophobic interactions. We demonstrated that the presence of hydrophobic interactions plays an important role in the acid-base properties of a polyelectrolyte in promoting the formation of compact conformations and hence decreasing the polyelectrolyte degree of ionization for a given pH-pK0 value.

  5. Biomimetic hydrogel materials (United States)

    Bertozzi, Carolyn; Mukkamala, Ravindranath; Chen, Qing; Hu, Hopin; Baude, Dominique


    Novel biomimetic hydrogel materials and methods for their preparation. Hydrogels containing acrylamide-functionalized carbohydrate, sulfoxide, sulfide or sulfone copolymerized with a hydrophilic or hydrophobic copolymerizing material selected from the group consisting of an acrylamide, methacrylamide, acrylate, methacrylate, vinyl and a derivative thereof present in concentration from about 1 to about 99 wt %. and methods for their preparation. The method of use of the new hydrogels for fabrication of soft contact lenses and biomedical implants.

  6. Biomimetic Hydrogel Materials

    Energy Technology Data Exchange (ETDEWEB)

    Bertozzi, Carolyn (Albany, CA), Mukkamala, Ravindranath (Houston, TX), Chen, Oing (Albany, CA), Hu, Hopin (Albuquerque, NM), Baude, Dominique (Creteil, FR)


    Novel biomimetic hydrogel materials and methods for their preparation. Hydrogels containing acrylamide-functionalized carbohydrate, sulfoxide, sulfide or sulfone copolymerized with a hydrophilic or hydrophobic copolymerizing material selected from the group consisting of an acrylamide, methacrylamide, acrylate, methacrylate, vinyl and a derivative thereof present in concentration from about 1 to about 99 wt %. and methods for their preparation. The method of use of the new hydrogels for fabrication of soft contact lenses and biomedical implants.

  7. Reovirus FAST Proteins Drive Pore Formation and Syncytiogenesis Using a Novel Helix-Loop-Helix Fusion-Inducing Lipid Packing Sensor.

    Directory of Open Access Journals (Sweden)

    Jolene Read


    Full Text Available Pore formation is the most energy-demanding step during virus-induced membrane fusion, where high curvature of the fusion pore rim increases the spacing between lipid headgroups, exposing the hydrophobic interior of the membrane to water. How protein fusogens breach this thermodynamic barrier to pore formation is unclear. We identified a novel fusion-inducing lipid packing sensor (FLiPS in the cytosolic endodomain of the baboon reovirus p15 fusion-associated small transmembrane (FAST protein that is essential for pore formation during cell-cell fusion and syncytiogenesis. NMR spectroscopy and mutational studies indicate the dependence of this FLiPS on a hydrophobic helix-loop-helix structure. Biochemical and biophysical assays reveal the p15 FLiPS preferentially partitions into membranes with high positive curvature, and this partitioning is impeded by bis-ANS, a small molecule that inserts into hydrophobic defects in membranes. Most notably, the p15 FLiPS can be functionally replaced by heterologous amphipathic lipid packing sensors (ALPS but not by other membrane-interactive amphipathic helices. Furthermore, a previously unrecognized amphipathic helix in the cytosolic domain of the reptilian reovirus p14 FAST protein can functionally replace the p15 FLiPS, and is itself replaceable by a heterologous ALPS motif. Anchored near the cytoplasmic leaflet by the FAST protein transmembrane domain, the FLiPS is perfectly positioned to insert into hydrophobic defects that begin to appear in the highly curved rim of nascent fusion pores, thereby lowering the energy barrier to stable pore formation.

  8. Tritium sorption behavior on the percolation of tritiated water into a soil packed bed

    Energy Technology Data Exchange (ETDEWEB)

    Furuichi, Kazuya, E-mail: [Department of Advanced Energy Engineering, Kyushu University, 6-1, Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Katayama, Kazunari; Date, Hiroyuki [Department of Advanced Energy Engineering, Kyushu University, 6-1, Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Takeishi, Toshiharu [Factory of Engineering, Kyushu University, 744 Motooka Nishi-ku, Fukuoka 819-0395 (Japan); Fukada, Satoshi [Department of Advanced Energy Engineering, Kyushu University, 6-1, Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan)


    Highlights: • We establish the permeation model of tritiated water in the soil layer. • Saturated hydraulic conductivity of water in soil was gained by using the model. • The isotope exchange reaction coefficient was good agreement with experimental data. - Abstract: Development of tritium transport model in natural soil is an important issue from a viewpoint of safety of fusion reactors. The spill of a large amount of tritiated water to the environment is a concern accident because huge tritiated water is handled in a fusion plant. In this work, a simple tritium transport model was proposed based on the tritium transport model in porous materials. The overall mass transfer coefficient representing isotope exchange reaction between tritiated water and structural water in soil particles was obtained by numerically analyzing the result of the percolation experiment of tritiated water into the soil packed bed. Saturated hydraulic conductivity in the natural soil packed bed was obtained to be 0.033 mm/s. By using this value, the overall mass transfer capacity coefficients representing the isotope exchange reaction between tritiated water percolating through the packed bed and overall structural water on soil particles was determined to be 6.0 × 10{sup −4} 1/s. This value is much smaller than the mass transfer capacity coefficient between tritiated water vapor and water on concrete material and metals.

  9. Phase behavior in quaternary ammonium ionic liquid-propanol solutions: Hydrophobicity, molecular conformations, and isomer effects (United States)

    Abe, Hiroshi; Kohki, Erica; Nakada, Ayumu; Kishimura, Hiroaki


    In ionic liquids (ILs), the effects of a quaternary ammonium cation containing a hydroxyl group were investigated and compared with the effect of a standard quaternary ammonium cation. The cation possessing a hydroxyl group is choline, Chol+, and the anion is bis(trifluoromethylsulfonyl)imide, TFSI-. Crystal polymorphism of pure [Chol][TFSI] was observed upon both cooling and heating by simultaneous X-ray diffraction and differential scanning calorimetry measurements. In contrast, [N3111][TFSI] (N3111+: N-trimethyl-N-propylammonium), a standard IL, demonstrated simple crystallization upon cooling. By adding 1-propanol or 2-propanol, the phase behaviors of the [Chol][TFSI]-based and [N3111][TFSI]-based mixtures were clearly distinguished. By Raman spectroscopy, the TFSI- anion conformers in the liquid state were shown to vary according to the propanol concentration, propanol isomer, and type of cation. The anomalous behaviors of pure [Chol][TFSI] and its mixtures are derived from hydrogen bonding of the hydroxyl group of Chol+ cation coupled with the hydrophobicity and packing efficiency of propanol.

  10. Hydrophobic Encapsulated Phosphonium Salts-Synthesis of Weakly Coordinating Cations and their Application in Wittig Reactions. (United States)

    Moritz, Ralf; Wagner, Manfred; Schollmeyer, Dieter; Baumgarten, Martin; Müllen, Klaus


    Large and rigid tetraarylphosphonium tetrafluoroborate salts have been synthesized representing weakly coordinating cations with diameters of several nanometers. Divergent dendritic growth by means of thermal Diels-Alder cycloaddition was employed for the construction of the hydrophobic polyphenylene framework up to the third generation. X-ray crystal structure analysis of first-generation phosphonium tetrafluoroborate supported the rigidity of the non-collapsible shell around the phosphorus center and gave insight into solid-state packing and cation-anion distances. Copper(I)-catalyzed azide-alkyne ligation served as reliable method for the preparation of a first-generation triazolylphenyl hybrid phosphonium cation under mild reaction conditions. Furthermore, from the synthesis of triarylbenzylphosphonium bromides, Wittig precursors with unprecedented bulky substituents in the α-position were accessible. Employment of these precursors under Wittig conditions by treatment with base and subsequent reaction with aldehydes preferentially provided (Z)-olefins with bulky polyphenylene substituents. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Fast charge implications: Pack and cell analysis and comparison (United States)

    Tanim, Tanvir R.; Shirk, Matthew G.; Bewley, Randy L.; Dufek, Eric J.; Liaw, Bor Yann


    This study investigates the effect of 50-kW (about 2C) direct current fast charging on a full-size battery electric vehicle's battery pack in comparison to a pack exclusively charged at 3.3 kW, which is the common alternating current Level 2 charging power level. Comparable scaled charging protocols are also independently applied to individual cells at three different temperatures, 20 °C, 30 °C, and 40 °C, to perform a comparative analysis with the packs. Dominant cell-level aging modes were identified through incremental capacity analysis and compared with full packs to gain a clear understanding of additional key factors that affect pack aging. While the cell-level study showed a minor impact on performance due to direct current fast charging, the packs showed a significantly higher rate of capacity fade under similar charging protocols. This indicates that pack-level aging cannot be directly extrapolated from cell evaluation. Delayed fast charging, completing shortly before discharge, was found to have less of an impact on battery degradation than conventional alternating current Level 2 charging.

  12. Identifying counterfeit cigarette packs using ultraviolet irradiation and light microscopy. (United States)

    Kurti, Marin; He, Yi; von Lampe, Klaus; Li, Yanlei


    Develop a method that yields high rates of sensitivity and specificity for determination of counterfeit cigarette packs for three popular brands: Newport, Marlboro ('Red') and Marlboro Gold. Using systematic keyword searches, we identified industry documents from the University of California, San Francisco's Legacy Tobacco Documents Library that describe the use of ultraviolet (UV) irradiation and close examination of printing quality to distinguish between counterfeit and genuine cigarette packs. Guided by these documents, we identified six markers for counterfeit cigarettes across three popular brands using counterfeit cigarette packs (N=68) seized by law enforcement agencies in the USA. We assessed the diagnostic test accuracy of these markers and tested it against genuine packs (N=22) using receiver operating characteristic curves analysis. We find that counterfeit cigarette packs fluoresce to long-wave UV irradiation and display poor printing quality. The optimal cut-off value varies among the three brands. For example, counterfeit Newport and Marlboro packaging can be reliably classified with two of six characteristics, while Marlboro Gold requires four. Researchers who conduct littered pack and pack swap studies are urged to include this method to assess the share of counterfeit cigarettes, and compare the result against tobacco industry figures. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to

  13. Properties Influencing Plasma Discharges in Packed Bed Reactors (United States)

    Kruszelnicki, Juliusz; Engeling, Kenneth W.; Foster, John E.; Kushner, Mark J.


    Atmospheric pressure dielectric barrier discharges (DBDs) sustained in packed bed reactors (PBRs) are being investigated for CO2 removal and conversion of waste gases into higher value compounds. We report on results of a computational investigation of PBR-DBD properties using the plasma hydrodynamics simulator nonPDPSIM with a comparison to experiments. Dielectric beads (rods in 2D) were inserted between two coplanar electrodes, 1 cm apart filled by humid air. A step-pulse of -30 kV was applied to the top electrode. Material properties of the beads (dielectric constant, secondary emission coefficient) and gas properties (photoionization and photo-absorption cross-sections, temperature) were varied. We found that photoionization plays a critical role in the propagation of the discharge through the PBR, as it serves to seed charges in regions of high electric field. Increasing rates of photo-ionization enable increases in the discharge propagation velocity, ionization rates and production of radicals. A transition between DBD-like and arc-like discharges occurs as the radiation mean free path decreases. Increasing the dielectric constant of the beads increased electric fields in the gas, which translated to increased discharge propagation velocity and charge density until ɛ/ɛ0 100. Secondary electron emission coefficient and gas temperature have minimal impacts on the discharge propagation though the latter did affect the production of reactive species. Work supported by US DOE Office of Fusion Energy Science and the National Science Foundation.

  14. Control of piezoelectricity in amino acids by supramolecular packing (United States)

    Guerin, Sarah; Stapleton, Aimee; Chovan, Drahomir; Mouras, Rabah; Gleeson, Matthew; McKeown, Cian; Noor, Mohamed Radzi; Silien, Christophe; Rhen, Fernando M. F.; Kholkin, Andrei L.; Liu, Ning; Soulimane, Tewfik; Tofail, Syed A. M.; Thompson, Damien


    Piezoelectricity, the linear relationship between stress and induced electrical charge, has attracted recent interest due to its manifestation in biological molecules such as synthetic polypeptides or amino acid crystals, including gamma (γ) glycine. It has also been demonstrated in bone, collagen, elastin and the synthetic bone mineral hydroxyapatite. Piezoelectric coefficients exhibited by these biological materials are generally low, typically in the range of 0.1-10 pm V-1, limiting technological applications. Guided by quantum mechanical calculations we have measured a high shear piezoelectricity (178 pm V-1) in the amino acid crystal beta (β) glycine, which is of similar magnitude to barium titanate or lead zirconate titanate. Our calculations show that the high piezoelectric coefficients originate from an efficient packing of the molecules along certain crystallographic planes and directions. The highest predicted piezoelectric voltage constant for β-glycine crystals is 8 V mN-1, which is an order of magnitude larger than the voltage generated by any currently used ceramic or polymer.

  15. Do gray wolves (Canis lupus) support pack mates during aggressive inter-pack interactions? (United States)

    Cassidy, Kira A; McIntyre, Richard T


    For group-living mammals, social coordination increases success in everything from hunting and foraging (Crofoot and Wrangham in Mind the Gap, Springer, Berlin, 2010; Bailey et al. in Behav Ecol Sociobiol 67:1-17, 2013) to agonism (Mosser and Packer in Anim Behav 78:359-370, 2009; Wilson et al. in Anim Behav 83:277-291, 2012; Cassidy et al. in Behav Ecol 26:1352-1360, 2015). Cooperation is found in many species and, due to its low costs, likely is a determining factor in the evolution of living in social groups (Smith in Anim Behav 92:291-304, 2014). Beyond cooperation, many mammals perform costly behaviors for the benefit of group mates (e.g., parental care, food sharing, grooming). Altruism is considered the most extreme case of cooperation where the altruist increases the fitness of the recipient while decreasing its own fitness (Bell in Selection: the mechanism of evolution. Oxford University Press, Oxford 2008). Gray wolf life history requires intra-pack familiarity, communication, and cooperation in order to succeed in hunting (MacNulty et al. in Behav Ecol doi: 10.1093/beheco/arr159 2011) and protecting group resources (Stahler et al. in J Anim Ecol 82: 222-234, 2013; Cassidy et al. in Behav Ecol 26:1352-1360, 2015). Here, we report 121 territorial aggressive inter-pack interactions in Yellowstone National Park between 1 April 1995 and 1 April 2011 (>5300 days of observation) and examine each interaction where one wolf interferes when its pack mate is being attacked by a rival group. This behavior was recorded six times (17.6 % of interactions involving an attack) and often occurred between dyads of closely related individuals. We discuss this behavior as it relates to the evolution of cooperation, sociality, and altruism.

  16. Hydrophobicity, surface tension, and zeta potential measurements of glass-reinforced hydroxyapatite composites. (United States)

    Lopes, M A; Monteiro, F J; Santos, J D; Serro, A P; Saramago, B


    Wettability and zeta potential studies were performed to characterize the hydrophobicity, surface tension, and surface charge of P2O5-glass-reinforced hydroxyapatite composites. Quantitative phase analysis was performed by the Rietveld method using GSAS software applied to X-ray diffractograms. Surface charge was assessed by zeta potential measurements. Protein adsorption studies were performed using vitronectin. Contact angles and surface tensions variation with time were determined by the sessile and pendent drop techniques, respectively, using ADSA-P software. The highest (-18.1 mV) and lowest (-28.7 mV) values of zeta potential were found for hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP), respectively, with composite materials presenting values in between. All studied bioceramic materials showed similar solid surface tension. For HA and beta-TCP, solid surface tensions of 46.7 and 45.3 mJ/m2, respectively, were obtained, while composites presented intermediate surface tension values. The dispersive component of surface tension was the predominant one for all materials studied. Adhesion work values between the vitronectin solution and HA and beta-TCP were found to be 79.8 and 88.0 mJ/m2, respectively, while the 4.0 wt % glass composites showed slightly lower values than the 2.5 wt % ones. The presence of beta-TCP influenced surface charge, hydrophobicity, and protein adsorption of the glass-reinforced HA composites, and therefore indirectly affected cell-biomaterial interactions.

  17. Synthesis and characterization of catalysts based on mesoporous silica partially hydrophobized for technological applications. (United States)

    Martins, Amanda R; Salviano, Adriana B; Oliveira, Aline A S; Mambrini, Raquel V; Moura, Flávia C C


    In this work, mesoporous silica mobil composition of matter no. 41 (MCM-41) was synthesized by the sol-gel method. Two different surface modifications were made to transform this material into a very active adsorbent and catalyst support: (i) impregnation of iron nanoparticles and (ii) hydrophobization via chemical vapor deposition (CVD) with ethanol. The materials prepared with different iron contents, i.e., 2.5, 5, and 10 %, after hydrophobization, were characterized by several techniques. CHN analysis and Raman spectroscopy proved that approximately 15 % of carbon is deposited during CVD process mainly as organized carbonaceous structures. The specific surface area was determined by the BET method as up to 1080 m2 g-1, which explains the excellent results of the materials in the adsorption of model dyes methylene blue and indigo carmine. Mössbauer spectroscopy, thermogravimetric (TG)/DTG analysis, and transmission electron microscopy (TEM) images showed that the iron supported may be partially reduced during the CVD process to Fe2+ species, which are stabilized by the carbon coating. This iron species plays an important role in the oxidation of different contaminants, such as quinoline and methylene blue. The results obtained in the catalytic tests showed to be very promising.

  18. Efficiency of blocking of non-specific interaction of different proteins by BSA adsorbed on hydrophobic and hydrophilic surfaces. (United States)

    Jeyachandran, Y L; Mielczarski, J A; Mielczarski, E; Rai, B


    The efficiency of a pre-absorbed bovine serum albumin (BSA) layer in blocking the non-specific adsorption of different proteins on hydrophobic and hydrophilic surfaces was evaluated qualitatively and quantitatively using infrared reflection spectroscopy supported by spectral simulations. A BSA layer with a surface coverage of 35% of a close-packed monolayer exhibited a blocking efficiency of 90-100% on a hydrophobic and 68-100% on a hydrophilic surface, with respect to the non-specific adsorption of concanavalin A (Con A), immunoglobulin G (IgG), and staphylococcal protein A (SpA). This BSA layer was produced using a solution concentration of 1 mg/mL and 30 min incubation time. BSA layers that were adsorbed at conditions commonly employed for blocking (a 12 h incubation time and a solution concentration of 10 mg/mL) exhibited a blocking activity that involved competitive adsorption-desorption. This activity resulted from the formation of BSA-phosphate surface complexes, which correlated with the conformation of adsorbed BSA molecules that was favourable for blocking. The importance of optimisation of the adsorbed BSA layer for different surfaces and proteins to achieve efficient blocking was addressed in this study.

  19. Mortality in trauma patients with active arterial bleeding managed by embolization or surgical packing

    DEFF Research Database (Denmark)

    Froberg, Lonnie; Helgstrand, Frederik; Clausen, Caroline


    and blood product consumption in trauma patients with active arterial haemorrhage in the abdominal and/or pelvic region treated with either angiography and embolization or explorative laparotomy and surgical packing. MATERIAL AND METHODS: From January 1(st) 2006 to December 31(st) 2011 2,173 patients...... with an ISS of >9 were admitted to the Trauma Centre of Copenhagen University Hospital, Rigshospitalet, Denmark. Of these, 66 patients met the inclusion criteria: age above 15 years and active arterial haemorrhage from the abdominal and/or pelvic region verified by a CT scan at admission. Gender, age, initial......OBJECTIVE: Exsanguination due to coagulopathy and vascular injury is a common cause of death among trauma patients. Arterial injury can be treated either by angiography and embolization or by explorative laparotomy and surgical packing. The purpose of this study was to compare 30-day mortality...

  20. Avoidance of cigarette pack health warnings among regular cigarette smokers. (United States)

    Maynard, Olivia M; Attwood, Angela; O'Brien, Laura; Brooks, Sabrina; Hedge, Craig; Leonards, Ute; Munafò, Marcus R


    Previous research with adults and adolescents indicates that plain cigarette packs increase visual attention to health warnings among non-smokers and non-regular smokers, but not among regular smokers. This may be because regular smokers: (1) are familiar with the health warnings, (2) preferentially attend to branding, or (3) actively avoid health warnings. We sought to distinguish between these explanations using eye-tracking technology. A convenience sample of 30 adult dependent smokers participated in an eye-tracking study. Participants viewed branded, plain and blank packs of cigarettes with familiar and unfamiliar health warnings. The number of fixations to health warnings and branding on the different pack types were recorded. Analysis of variance indicated that regular smokers were biased towards fixating the branding rather than the health warning on all three pack types. This bias was smaller, but still evident, for blank packs, where smokers preferentially attended the blank region over the health warnings. Time-course analysis showed that for branded and plain packs, attention was preferentially directed to the branding location for the entire 10s of the stimulus presentation, while for blank packs this occurred for the last 8s of the stimulus presentation. Familiarity with health warnings had no effect on eye gaze location. Smokers actively avoid cigarette pack health warnings, and this remains the case even in the absence of salient branding information. Smokers may have learned to divert their attention away from cigarette pack health warnings. These findings have implications for cigarette packaging and health warning policy. Copyright © 2014 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.