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Sample records for superhydrophobic fibrous mats

  1. Permeability of Electrospun Superhydrophobic Nanofiber Mats

    Directory of Open Access Journals (Sweden)

    Sarfaraz U. Patel

    2012-01-01

    Full Text Available This paper discusses the fabrication and characterization of electrospun nanofiber mats made up of poly(4-methyl-1-pentene polymer. The polymer was electrospun in different weight concentrations. The mats were characterized by their basis weight, fiber diameter distribution, contact angles, contact angle hysteresis, and air permeability. All of the electrospun nonwoven fiber mats had water contact angles greater than 150 degrees making them superhydrophobic. The permeabilities of the mats were empirically fitted to the mat basis weight by a linear relation. The experimentally measured air permeabilities were significantly larger than the permeabilities predicted by the Kuwabara model for fibrous media.

  2. Conversion of an electrospun nanofibrous cellulose acetate mat from a super-hydrophilic to super-hydrophobic surface

    Science.gov (United States)

    Ding, Bin; Li, Chunrong; Hotta, Yoshio; Kim, Jinho; Kuwaki, Oriha; Shiratori, Seimei

    2006-09-01

    We report a new approach to convert an electrospun nanofibrous cellulose acetate mat surface from super-hydrophilic to super-hydrophobic. Super-hydrophilic cellulose acetate nanofibrous mats can be obtained by electrospinning hydrophilic cellulose acetate. The surface properties of the fibrous mats were modified from super-hydrophilic to super-hydrophobic with a simple sol-gel coating of decyltrimethoxysilane (DTMS) and tetraethyl orthosilicate (TEOS). The resultant samples were characterized by field emission scanning electron microscopy (FE-SEM), x-ray photoelectron spectroscopy (XPS), water contact angle, Brunauer-Emmett-Teller (BET) surface area, atomic force microscopy (AFM), and UV-visible measurements. The results of FE-SEM and XPS showed that the sol-gel (I) films were formed on the rough fibrous mats only after immersion in sol-gel. After the sol-gel (I) coating, the cellulose acetate fibrous mats formed in both 8 and 10 wt% cellulose acetate solutions showed the super-hydrophobic surface property. Additionally, the average sol-gel film thickness coated on 10 wt% cellulose acetate fibrous mats was calculated to be 80 nm. The super-hydrophobicity of fibrous mats was attributed to the combined effects of the high surface roughness of the electrospun nanofibrous mats and the hydrophobic DTMS sol-gel coating. Additionally, hydrophobic sol-gel nanofilms were found to be transparent according to UV-visible measurements.

  3. Electrospinning of caseinates to create protective fibrous mats

    Science.gov (United States)

    Electrospinning is a nonthermal process that produces fibers on the micron- or nano-scale from a polymer solution. If produced by electrospinning of biopolymer solutions, fibrous mats may be created for protecting foods and allowing for the preservation and controlled release of bioactives for healt...

  4. Super-Hydrophobic High Throughput Electrospun Cellulose Acetate (CA) Nanofibrous Mats as Oil Selective Sorbents

    Science.gov (United States)

    Han, Chao

    The threat of oil pollution increases with the expansion of oil exploration and production activities, as well as the industrial growth around the world. Use of sorbents is a common method to deal with the oil spills. In this work, an advanced sorbent technology is described. A series of non-woven Cellulose Acetate (CA) nanofibrous mats with a 3D fibrous structure were synthesized by a novel high-throughput electrospinning technique. The precursor was solutions of CA/ acetic acid-acetone in various concentrations. Among them, 15.0% CA exhibits a superhydrophobic surface property, with a water contact angle of 128.95°. Its oil sorption capacity is many times higher the oil sorption capacity of the best commercial sorbent available in the market. Also, it showed good buoyancy properties on the water both as dry-mat and oil-saturated mat. In addition, it is biodegradable, easily available, easily manufactured, so the CA nanofibrous mat is an excellent candidate as oil sorbent for oil spill in water treatment.

  5. Alternating magnetic field heat behaviors of PVDF fibrous mats filled with iron oxide nanoparticles

    Directory of Open Access Journals (Sweden)

    Jinu Kim

    2016-05-01

    Full Text Available To study the magnetic heat behaviors, iron oxide nanoparticles (IONPs and the polyvinylidene fluoride (PVDF fibrous mats filled with IONPs were prepared by using coprecipitaion method and the electrospinning technique. The synthesized IONPs exhibited a magnetization of about 72 emu/g with average diameter of about 10 nm. The magnetizations of PVDF fibrous mats filled with IONPs showed 2.6 emu/g, 5.5 emu/g and 9.9 emu/g for 5 wt.%, 10 wt.% and 20 wt.% IONPs concentration, respectively. The heat of the magnetic fibrous mats were measured under various alternating magnetic fields (90, 128, and 167 Oe, frequencies (190, 250 and 355 kHz. The maximum saturated temperature showed up to 62 °C for 20 wt.% IONPs filled in PVDF fibrous mat under 167 Oe and 355 kHz.

  6. Alternating magnetic field heat behaviors of PVDF fibrous mats filled with iron oxide nanoparticles

    Science.gov (United States)

    Kim, Jinu; Choi, Jung-Su; Yang, Heejae; Ko, Frank K.; Kim, Ki Hyeon

    2016-05-01

    To study the magnetic heat behaviors, iron oxide nanoparticles (IONPs) and the polyvinylidene fluoride (PVDF) fibrous mats filled with IONPs were prepared by using coprecipitaion method and the electrospinning technique. The synthesized IONPs exhibited a magnetization of about 72 emu/g with average diameter of about 10 nm. The magnetizations of PVDF fibrous mats filled with IONPs showed 2.6 emu/g, 5.5 emu/g and 9.9 emu/g for 5 wt.%, 10 wt.% and 20 wt.% IONPs concentration, respectively. The heat of the magnetic fibrous mats were measured under various alternating magnetic fields (90, 128, and 167 Oe), frequencies (190, 250 and 355 kHz). The maximum saturated temperature showed up to 62 °C for 20 wt.% IONPs filled in PVDF fibrous mat under 167 Oe and 355 kHz.

  7. Superhydrophobic, Hybrid, Electrospun Cellulose Acetate Nanofibrous Mats for Oil/Water Separation by Tailored Surface Modification.

    Science.gov (United States)

    Arslan, Osman; Aytac, Zeynep; Uyar, Tamer

    2016-08-03

    Electrospun cellulose acetate nanofibers (CA-NF) have been modified with perfluoro alkoxysilanes (FS/CA-NF) for tailoring their chemical and physical features aiming oil-water separation purposes. Strikingly, hybrid FS/CA-NF showed that perfluoro groups are rigidly positioned on the outer surface of the nanofibers providing superhydrophobic characteristic with a water contact angle of ∼155°. Detailed analysis showed that hydrolysis/condensation reactions led to the modification of the acetylated β(1 → 4) linked d-glucose chains of CA transforming it into a superhydrophobic nanofibrous mat. Analytical data have revealed that CA-NF surfaces can be selectively controlled for fabricating the durable, robust and water resistant hybrid electrospun nanofibrous mat. The -OH groups available on the CA structure allowed the basic sol-gel reactions started by the reactive FS hybrid precursor system which can be monitored by spectroscopic analysis. Since alkoxysilane groups on the perfluoro silane compound are capable of reacting for condensation together with the CA, superhydrophobic nanofibrous mat is obtained via electrospinning. This structural modification led to the facile fabrication of the novel oil/water nanofibrous separator which functions effectively demonstrated by hexane/oil and water separation experiments. Perfluoro groups consequently modified the hydrophilic CA nanofibers into superhydrophobic character and therefore FS/CA-NF could be quite practical for future applications like water/oil separators, as well as self-cleaning or water resistant nanofibrous structures.

  8. Preparation and Characterization of Polyvinylidene Fluoride/Graphene Superhydrophobic Fibrous Films

    Directory of Open Access Journals (Sweden)

    Rasoul Moradi

    2015-08-01

    Full Text Available A new strategy to induce superhydrophobicity via introducing hierarchical structure into the polyvinylidene fluoride (PVDF film was explored in this study. For this purpose nanofibrous composite films were prepared by electrospinning of PVDF and PVDF/graphene blend solution as the main precursors to produce a net-like structure. Various spectroscopy and microscopy methods in combination with crystallographic and wettability tests were used to evaluate the characteristics of the synthesized films. Mechanical properties have been studied using a universal stress-strain test. The results show that the properties of the PVDF nanofibrous film are improved by compositing with graphene. The incorporation of graphene flakes into the fibrous polymer matrix changes the morphology, enhances the surface roughness, and improves the hydrophobicity by inducing a morphological hierarchy. Superhydrophobicity with the water contact angle of about 160° can be achieved for the PVDF/graphene electrospun nanocomposite film in comparison to PVDF pristine film.

  9. Robust superhydrophobic mats based on electrospun crystalline nanofibers combined with a silane precursor.

    Science.gov (United States)

    Park, Song Hee; Lee, Song Min; Lim, Ho Sun; Han, Joong Tark; Lee, Dong Ryeol; Shin, Hwa Sung; Jeong, Youngjin; Kim, Jooyong; Cho, Jeong Ho

    2010-03-01

    We demonstrate the fabrication of solvent-resistant, mechanically robust, superhydrophobic nanofibrous mats by electrospinning of poly(vinylidene fluoride) (PVDF) in the presence of inorganic silane materials. The solvent resistance and mechanical strength of nanofibrous mats were dramatically increased through the crystallization of as-spun PVDF fibers or incorporation of a tetraethyl orthosilicate (TEOS) sol into the nanofibrous matrix. The electrospun nanofibrous mats yielded a water contact angle of 156 degrees that did not vary with TEOS content. The solvent resistance and mechanical robustness of the electrospun mats were significantly enhanced through extensive cross-linking of TEOS, even after short PVDF annealing times. The interpenetrating polymer network, which embeds polymer chains in a TEOS network, allows the fabrication of robust functional nanofibers by combining semicrystalline polymers with electrospinning techniques.

  10. Fabrication and characterization of superhydrophobic and superlipophilic silica nanofibers mats with excellent heat resistance

    Directory of Open Access Journals (Sweden)

    Gao S.

    2016-01-01

    Full Text Available A kind of silica nanofibers (SNF mats with superhydrophobicity and superlipophilicity as well as excellent heat resistance, had been prepared by modifying of 1, 1, 1, 3, 3, 3-hexamethyldisilazane on electrospun SNF mats. The effects of heat treatment time on properties of modified SNF mats were investigated by scanning electron microscopy, nitrogen absorption analysis, X-ray photoelectron spectroscopy, and contact angle measurement. With high specific surface area 240.1 m2/g, the optimal modified SNF mat approached water contact angle (WCA 153.2° and fuel contact angle (FCA 0°, furthermore, even after annealing by 450°C in air for 1h , WCA remained at 135.5° and FCA kept at 3.8°, which opened a new way to improve heat resistance of fuel-water filter paper.

  11. Superhydrophobic PVDF and PVDF-HFP nanofibrous mats with antibacterial and anti-biofouling properties

    Science.gov (United States)

    Spasova, M.; Manolova, N.; Markova, N.; Rashkov, I.

    2016-02-01

    Superhydrophobic nanofibrous materials of poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) were prepared by one-pot electrospinning technique. The mats were decorated with ZnO nanoparticles with silanized surface and a model drug - 5-chloro-8-hydroxyquinolinol (5Cl8HQ). The obtained hybrid nanofibrous materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), contact angle measurements, mechanical and microbiological tests. The results showed that the incorporation of ZnO nanoparticles into PVDF and PVDF-HFP nanofibers increased the hydrophobicity (contact angle 152°), improved the thermal stability and imparted to the nanofibrous materials anti-adhesive and antimicrobial properties. The mats containing the model drug possessed antibacterial activity against Escherichia coli and Staphylococcus aureus. The results suggested that the obtained hybrid mats could find potential biomedical applications requiring antibacterial and anti-biofouling properties.

  12. A Cyanine Dye Encapsulated Porous Fibrous Mat for Naked-Eye Ammonia Sensing.

    Science.gov (United States)

    Ji, Chendong; Ma, Lijing; Yin, Meizhen; Yang, Wantai; Pan, Kai

    2016-08-19

    Electrospun ultrathin fiber-based sensors are desirable because of their practicality and sensitivity. Ammonia-detection systems are in high demand in different areas, including the industrial and agricultural fields. However, current technologies rely on large and complex instruments that restrict their actual utilization. Herein, we report a flexible naked-eye ammonia sensor, the polylactic acid-cyanine (PLA-Cy) fibrous mat, which was fabricated by blending a carboxyl-functionalized cyanine dye (D1) into electospun PLA porous fibers. The sensing mat was shown to undergo a naked-eye-detectable color change from white to blue upon exposure to ammonia vapor. The mat showed high selectivity to ammonia gas with a detection limit of 3.3 ppm. Aggregated D1 was first encapsulated by PLA and was then ionized by NH3 . These mechanisms were examined by photophysical studies and scanning electron microscopy. The aggregation-deaggregation process of D1 in the PLA-Cy fibrous mat led to the color change. This work provides a facile method for the naked-eye detection of ammonia and a novel strategy for the use of organic dyes in ammonia sensing.

  13. Superhydrophobic PVDF and PVDF-HFP nanofibrous mats with antibacterial and anti-biofouling properties

    Energy Technology Data Exchange (ETDEWEB)

    Spasova, M.; Manolova, N. [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St, bl. 103A, BG-1113 Sofia (Bulgaria); Markova, N. [Institute of Microbiology, Bulgarian Academy of Sciences, Acad. G. Bonchev St, bl. 26, BG-1113 Sofia (Bulgaria); Rashkov, I., E-mail: rashkov@polymer.bas.bg [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St, bl. 103A, BG-1113 Sofia (Bulgaria)

    2016-02-15

    Graphical abstract: - Highlights: • New PVDF and PVDF-HFP nanofibers decorated with ZnO nanoparticles and a model drug. • The nanofibrous materials were fabricated by one-pot electrospinning. • The obtained materials are superhybrophobic and possess antibacterial properties. - Abstract: Superhydrophobic nanofibrous materials of poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) were prepared by one-pot electrospinning technique. The mats were decorated with ZnO nanoparticles with silanized surface and a model drug – 5-chloro-8-hydroxyquinolinol (5Cl8HQ). The obtained hybrid nanofibrous materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), contact angle measurements, mechanical and microbiological tests. The results showed that the incorporation of ZnO nanoparticles into PVDF and PVDF-HFP nanofibers increased the hydrophobicity (contact angle 152°), improved the thermal stability and imparted to the nanofibrous materials anti-adhesive and antimicrobial properties. The mats containing the model drug possessed antibacterial activity against Escherichia coli and Staphylococcus aureus. The results suggested that the obtained hybrid mats could find potential biomedical applications requiring antibacterial and anti-biofouling properties.

  14. Coaxially electrospun PVDF-Teflon AF and Teflon AF-PVDF core-sheath nanofiber mats with superhydrophobic properties.

    Science.gov (United States)

    Muthiah, Palanikkumaran; Hsu, Shu-Hau; Sigmund, Wolfgang

    2010-08-03

    This work reports the coaxial electrospinning of poly(vinylidene fluoride) (PVDF)-Teflon amorphous fluoropolymer (AF) and Teflon AF-PVDF core-sheath nanofiber mats yielding superhydrophobic properties. The coaxial electrospinning configuration allows for the electrospinning of Teflon AF, a nonelectrospinnable polymer, with the help of an electrospinnable PVDF polymer. PVDF-Teflon AF and Teflon AF-PVDF core-sheath fibers have been found to a have mean fiber diameter ranging from 400 nm to less than 100 nm. TEM micrographs exhibit a typical core-sheath fiber structure for these fibers, where the sheath fiber coats the core fiber almost thoroughly. Water contact angle measurements by sessile drop method on these core-sheath nanofiber mats exhibited superhydrophobic characteristics with contact angles close to or higher than 150 degrees. Surprisingly, PVDF-Teflon AF and Teflon AF-PVDF nanofiber mat surface properties were dominated by the fiber dimensions and less influenced by the type of sheath polymer. This suggests that highly fluorinated polymer Teflon AF does not advance the hydrophobicity beyond what surface physics and slightly fluorinated polymer PVDF can achieve. It is concluded that PVDF-Teflon AF and Teflon AF-PVDF core-sheath electrospun nanofiber mats may be used in lithium (Li)-air batteries.

  15. 静电纺丝制备CMCAB超疏水纤维材料%Preparation of superhydrophobic CMCAB fibrous material by electrospinning

    Institute of Scientific and Technical Information of China (English)

    谢龙; 邵自强

    2012-01-01

    Nano-fibrous carboxymethylcellulose acetate butyrate (CMCAB) mats with excellent superhydrophobicity (water contact angle 155°) were prepared by electrospinning the kind of biodegradable cellulose derivative. By analyzing the SEM image of CMCAB fibers prepared under different solvent system, it is found that the fibers have groove surface at the solvent of methylene dichloride/ethanol with the composition of 8/2 (w/w). AFM image reveal that the CMCAB mats have concave-convex surface and resembled the rough surface of lotus leaves. Hydrophobicity of CMCAB mats are strongly influenced by average diameter and surface roughness of CMCAB fiber via the determination of water contact angle. In order to improve its hydrophobicity,the effect of solution concentration and voltage on average diameter were researched and the electrospinning conditions were optimized based on the above results.%以环境友好的纤维素衍生物羧甲基纤维素醋酸丁酸酯(CMCAB)为原料,采用静电纺丝技术构筑仿生粗糙疏水表面,成功制备了CMCAB超疏水纤维材料(4g触角155°)。采用SEM研究了不同溶剂体系下纤维的直径和表面形貌,质量比为8:2的二氯甲烷和乙醇混合溶剂制备的纤维表面粗糙。通过原子力显微镜测试,材料表面凹凸起伏,具有类似荷叶的微结构。测定材料的接触角,发现纤维的直径和粗糙度是影响疏水性的关键。在此基础上,为提高材料的疏水性,研究了溶液浓度和电压对纤维平均直径的影响规律,优化了制备CMCAB超疏水材料的纺丝工艺。

  16. Preparation and Characterization of Polyvinylidene Fluoride/Graphene Superhydrophobic Fibrous Films

    OpenAIRE

    Rasoul Moradi; Javad Karimi-Sabet; Mojtaba Shariaty-Niassar; Mohammad A. Koochaki

    2015-01-01

    A new strategy to induce superhydrophobicity via introducing hierarchical structure into the polyvinylidene fluoride (PVDF) film was explored in this study. For this purpose nanofibrous composite films were prepared by electrospinning of PVDF and PVDF/graphene blend solution as the main precursors to produce a net-like structure. Various spectroscopy and microscopy methods in combination with crystallographic and wettability tests were used to evaluate the characteristics of the synthesized f...

  17. The Sink Term to Different Kinds of Fibrous Mat During the Unsaturated Filling Process

    Science.gov (United States)

    Lee, Yongjing; Yan, Shilin; Lee, Dequan; Yan, Fei

    2016-06-01

    The fibrous pre-form of resin transfer molding is a dual-scale porous medium with two distinct scales of pores, i.e., pores in intra- and inter-tow, which produce an unsaturated infiltration phenomenon during filling. A sink term representing the delayed flow rate from the inter-tow gap into the intra-tow one is introduced to establish governing equations. This study mainly analyzes the sink term by tow saturation during the microscopic flow. First, fiber-tow permeability is calculated by FLOTRAN of ANSYS, Second, periodic unit cells are built according to different structures, and the concrete expression of the sink term is indirectly obtained through the numerical simulation and date fitting of tow saturation under different pressure and viscosity conditions. Results indicate that: the FLOTRAN module can be used to calculate the permeability of fiber tow in two directions; Moreover, the filling time and infiltration process for diverse unit cells with the same volume fraction are different; under the same injection condition, different unit cells have different parameters for the sink term.

  18. The effect of poly (lactic-co-glycolic) acid composition on the mechanical properties of electrospun fibrous mats.

    Science.gov (United States)

    Liu, X; Aho, J; Baldursdottir, S; Bohr, A; Qu, H; Christensen, L P; Rantanen, J; Yang, M

    2017-08-30

    The aim of this study was to investigate the influence of polymer molecular structure on the electrospinnability and mechanical properties of electrospun fibrous mats (EFMs). Polymers with similar molecular weight but different composition ratios (lactic acid (LA) and glycolic acid (GA)) were dissolved in binary mixtures of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF). The intrinsic viscosity and rheological properties of polymer solutions were investigated prior to electrospinning. The morphology and mechanical properties of the resulting EFMs were characterized by scanning electron microscope (SEM) and dynamic mechanical analysis (DMA). Sufficiently high inter-molecular interactions were found to be a prerequisite to ensure the formation of fibers in the electrospinning process, regardless the polymer composition. The higher the amount of GA in the polymer composition, the more ordered and entangled molecules were formed after electrospinning from the solution in THF-DMF, which resulted in higher Young's modulus and tensile strength of the EFMs. In conclusion, this study shows that the mechanical properties of EFMs, which depend on the polymer molecule-solvent affinity, can be predicted by the inter-molecular interactions in the starting polymer solutions and over the drying process of electrospinning. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Versatility of electrospinning in the fabrication of fibrous mat and mesh nanostructures of bismuth ferrite (BiFeO3) and their magnetic and photocatalytic activities.

    Science.gov (United States)

    Bharathkumar, S; Sakar, M; K, Rohith Vinod; Balakumar, S

    2015-07-21

    This study demonstrates the fabrication of electrospun bismuth ferrite (BiFeO3/BFO) fiber mat and fibrous mesh nanostructures consisting of aligned and random fibers respectively. The formation of these one dimensional (1D) nanostructures was mediated by the drum and plate collectors in the electrospinning process that yielded aligned and random nanofibers of BFO respectively. The single phase and rhombohedral crystal structure of the fabricated 1D BFO nanostructures are confirmed through X-ray diffraction (XRD) studies. X-ray photoelectron spectroscopy (XPS) studies indicated that the fabricated fibers are stoichiometric BFO with native oxidation states +3. The surface texture and morphology are analyzed using the field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM) techniques. The average size of fibers in mat and mesh nanostructures is found to be 200 nm and 150 nm respectively. The band gap energy of BFO mat and mesh deduced from their UV diffuse reflectance spectra (UV-DRS) was found to be 2.44 eV and 2.39 eV, respectively, which evidenced the improved visible light receptivity of BFO mesh compared to that of the mat. Magnetization studies using a super conducting quantum interference device (SQUID) magnetometer revealed the weak ferromagnetic properties of BFO mesh and mat nanostructures that could emerge due to the dimension induced suppression of cycloidal spin structures. The photocatalytic degradation properties of the fibrous mesh are found to be enhanced compared to that of the mat. This could be attributed to the reduced band gap energy and an improved semiconductor band-bending phenomenon in the mesh that favoured the transportation of excited charge carriers to the photocatalyst-dye interfaces and the production of more number of reactive species that lead to the effective degradation of the dye molecules.

  20. MAGNOLOL ENTRAPPED ULTRA-FINE FIBROUS MATS ELECTROSPUN FROM POLY(ETHYLENE GLYCOL)-b-POLY(L-LACTIDE) AND IN VITRO RELEASE

    Institute of Scientific and Technical Information of China (English)

    Hao Wang; Hong-rui Song; Yong Cui; Ying-jie Deng; Xue-si Chen

    2011-01-01

    Ultra-fine fibrous mats with magnolol entrapped have been prepared by electrospinning biodegradable copolymer poly(ethylene glycol) blocked poly(L-lactide). Drug entrapment was perfect which was confirmed by scanning electron microscopy and differential scanning calorimetry. According to in vitro drug release investigation by high performance liquid chromatography, it was found that fibers with 10%, 20% and 30% drug entrapped respect to polymer (mass ratio) presented dramatically different drug release behavior and degradation behavior under the effect of proteinase K. The reason may be that fibers with 10% drug entrapped was more easily affected by enzyme while, to some degree, magnolol in fibers with 20% and 30% entrapped prevented polymer from being degraded by enzyme.

  1. Non-woven fibrous materials with antibacterial properties prepared by tailored attachment of quaternized chitosan to electrospun mats from maleic anhydride copolymer.

    Science.gov (United States)

    Ignatova, Milena; Petkova, Zhanina; Manolova, Nevena; Markova, Nadya; Rashkov, Iliya

    2012-01-01

    In order to impart antibacterial properties to microfibrous electrospun materials from styrene/maleic anhydride copolymers, quaternized chitosan derivatives (QCh) containing alkyl substituents of different chain lengths are covalently attached to the mats. A complete inhibition of the growth of bacteria, S. aureus (Gram-positive) and E. coli (Gram-negative), for a contact time of 30–120 min or a decrease of the bacterial titer by 2–3 log units is observed depending on the quaternization degree, the chain length of the alkyl substituent, and the molar mass of QCh. The modified mats are also effective in suppressing the adhesion of pathogenic S. aureus bacteria.

  2. 环糊精/聚苯乙烯超细复合纤维膜的制备及其吸附性能研究∗%Preparation and properties of cyclodextrins/polystyrene (CDs/PS) ultrafine composite fibrous mats

    Institute of Scientific and Technical Information of China (English)

    彭克林; 陈长中; 柳文敏; 潘万里

    2015-01-01

    采用静电纺丝技术分别制备了不同种类和含量的环糊精/聚苯乙烯(CDs/PS)超细复合纤维膜并研究了其吸附性能。利用扫描电镜(SEM)、红外光谱(FTIR)、X 射线衍射(XRD)等测试手段对纤维的形貌、组成和结晶性能进行了表征。通过紫外吸收光谱(UV)研究了复合纤维对对硝基苯酚的吸附,发现纤维的吸附性能与环糊精种类和含量有密切关系。在相同的环糊精含量时,复合纤维的吸附性能顺序为β-CD/PS >α-CD/PS >γ-CD/PS;而在相同的环糊精种类时,则纤维的吸附性能随环糊精含量增加而增大。%Cyclodextrins/polystyrene (CDs/PS)functional fibrous mats were successfully produced by electro-spinning for organic waste treatment.It is found that the presence of CDs facilitates the electrospinning of bead-free fibrous mats from the blend solutions,and the average fiber diameter decreased with increasing CD content. The wide-angle X-ray diffraction (WAXD)spectra of CDs/PS fibrous mats have no significant diffraction peaks, which indicates that the CD molecules are homogeneously distributed within the fibers and does not form any phase separated crystalline aggregates.The adsorption study reveals that the adsorptive capacity of the CDs/PS fibrous mats increased with the CD content,and the order of the adsorptive capacity isβ-CD/PS >α-CD/PS >γ-CD/PS with the same CD content.The CDs/PS functionalized fibrous mats may have the potential to be used in waste treatment.

  3. Superhydrophobic surfaces

    Science.gov (United States)

    Wang, Evelyn N; McCarthy, Matthew; Enright, Ryan; Culver, James N; Gerasopoulos, Konstantinos; Ghodssi, Reza

    2015-03-24

    Surfaces having a hierarchical structure--having features of both microscale and nanoscale dimensions--can exhibit superhydrophobic properties and advantageous condensation and heat transfer properties. The hierarchical surfaces can be fabricated using biological nanostructures, such as viruses as a self-assembled nanoscale template.

  4. Fibrous dysplasia

    Science.gov (United States)

    ... chap 22. Czerniak B. Fibrous dysplasia and related lesions. In: Czerniak B, ed. Bone Tumors. 2nd ... Assistant Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also ...

  5. Talking Mats

    DEFF Research Database (Denmark)

    2012-01-01

    Talking Mats are visualizations in the handy size of a set of cards used to support interviews with people with mental disabilities.......Talking Mats are visualizations in the handy size of a set of cards used to support interviews with people with mental disabilities....

  6. Superhydrophobic diatomaceous earth

    Science.gov (United States)

    Simpson, John T [Clinton, TN; D& #x27; Urso, Brian R [Clinton, TN

    2012-07-10

    A superhydrophobic powder is prepared by coating diatomaceous earth (DE) with a hydrophobic coating on the particle surface such that the coating conforms to the topography of the DE particles. The hydrophobic coating can be a self assembly monolayer of a perfluorinated silane coupling agent. The DE is preferably natural-grade DE where organic impurities have been removed. The superhydrophobic powder can be applied as a suspension in a binder solution to a substrate to produce a superhydrophobic surface on the substrate.

  7. Superhydrophobic functionalized graphene aerogels.

    Science.gov (United States)

    Lin, Yirong; Ehlert, Gregory J; Bukowsky, Colton; Sodano, Henry A

    2011-07-01

    Carbon-based nanomaterials such as carbon nanotubes and graphene are excellent candidates for superhydrophobic surfaces because of their intrinsically high surface area and nonpolar carbon structure. This paper demonstrates that graphene aerogels with a silane surface modification can provide superhydrophobicity. Graphene aerogels of various concentrations were synthesized and the receding contact angle of a water droplet was measured. It is shown that graphene aerogels are hydrophobic and become superhydrophobic following the application of a fluorinated surfactant. The aerogels produced for this experiment outperform previous carbon nanomaterials in creating superhydrophobic surfaces and offer a more scalable synthetic procedure for production.

  8. Superhydrophobicity from microstructured surface

    Institute of Scientific and Technical Information of China (English)

    ZHENG Lijun; WU Xuedong; LOU Zeng; WU Dan

    2004-01-01

    Superhydrophobicity is referred to the wettability of a solid surface which has a water apparent contact angle greater than 150°. It has attracted great interest in both fundamental researches and practical applications. This paper discusses two models: Wenzel model and Cassie model, to describe the superhydrophobic states of surface. The effectsof surface morphology and microstructure on superhydrophobicity are discussed, and the internal relationship between Wenzel and Cassie states is presented. These two su perhydrophobic states can coexist and they present different properties on contact angle hysteresis. It is reported that the irreversible transition can be realized from Cassie state to Wenzel state under some certain conditions. This paper also gives a review of recent progresses in the strategies of fabricating superhydrophobic surfaces by designing microstructured or microtextured surfaces. Finally, the fundamental research and applications of superhydrophobic surfaces are prospected.

  9. Degradabilidade ruminal da matéria seca, da fração fibrosa e da proteína bruta de forrageiras Forages dry matter, fibrous fraction and crude protein ruminal degradability

    Directory of Open Access Journals (Sweden)

    Aureliano José Vieira Pires

    2006-04-01

    Full Text Available O objetivo deste trabalho foi avaliar a degradabilidade ruminal da matéria seca, da fibra em detergente neutro, da fibra em detergente ácido e da proteína bruta da alfafa (Medicago sativa, aveia-preta (Avena strigosa, leucena (Leucaena leucocephala e guandu (Cajanus cajan. Amostras de 3 g das forragens foram incubadas no rúmen de três novilhos por períodos de 0, 6, 12, 24, 36, 48 e 72 horas. As degradabilidades efetivas da matéria seca da alfafa e da aveia, para a taxa de passagem de 5% por hora, foram elevadas (acima de 60%. A leucena e o guandu apresentaram valores inferiores, 50,9 e 56,0%, respectivamente. A partir de 24 horas de incubação, a aveia se destacou com maior desaparecimento da fibra em detergente neutro e da fibra em detergente ácido, e ainda apresentou as mais elevadas taxas de degradação efetiva destas frações. A aveia foi a forragem que apresentou maior degradabilidade da matéria seca, da fibra em detergente neutro, da fibra em detergente ácido e da proteína bruta no rúmen. O guandu, entretanto, foi a forragem com as piores taxas de degradação.The objective of this work was to evaluate ruminal degradability of dry matter, neutral detergent fiber, acid detergent fiber and crude protein of alfalfa (Medicago sativa, black oat (Avena strigosa, leucaena (Leucaena leucocephala and pigeon pea (Cajanus cajan. Samples of 3 g of forages were incubated in the rumen of three steers for 0, 6, 12, 24, 36, 48 and 72 hours periods. The dry matter effective degradabilities of alfalfa and oat, for a passage rate of 5%/hour, were high (over 60%. However, leucaena and pigeon pea showed lower values, 50.9 and 56.0%, respectively. From 24-hour incubation period on, the oat presented the highest neutral detergent fiber and acid detergent fiber disappearance and showed the greatest effective degradation rates of these fractions. The oat was the forage with the highest dry matter, neutral detergent fiber, acid detergent fiber and

  10. Effects of compression on the sound absorption of fibrous

    DEFF Research Database (Denmark)

    Castagnede, Bernard; Akninen, Achour; Brouard, Achour

    2000-01-01

    During the compression of a fibrous mat, it is well known that the absorption properties are decreasing. In order to predict this change, some heuristic formulae are proposed which take into account the modifications of the physical parameters(porosity, resistivity, tortousity and shappe factors)......) which enter in the standard "equivalent fluid" model. Numerical predictions are then discussed and compared to experimental data obtained on a fibrous material(uncompressed and the compressed) used in automotive industry....

  11. Dielectric behavior characterization of functional fibrous-ceramic/polymer nanocomposites

    OpenAIRE

    Dağdeviren, Canan; Dagdeviren, Canan

    2009-01-01

    This study is mainly focused on forming fibrous-ceramic/polymer nanocomposites and characterizing their dielectric behavior. The fibrous-ZnO/PVDF nanocomposite is prepared in two steps. First, a network of nano-scale zinc oxide (ZnO) fibers is produced by sintering electrospun PVA/Zinc Acetate fibers. Second, the ZnO fibrous non-woven mat is sandwiched between two polyvinylidine fluoride (PVDF) thermoplastic polymer films by hot-press casting. Referring to the extensive literature search with...

  12. Interfacial microfluidic transport on micropatterned superhydrophobic textile.

    Science.gov (United States)

    Xing, Siyuan; Jiang, Jia; Pan, Tingrui

    2013-05-21

    Textile-enabled interfacial microfluidics, utilizing fibrous hydrophilic yarns (e.g., cotton) to guide biological reagent flows, has been extended to various biochemical analyses recently. The restricted capillary-driving mechanism, however, persists as a major challenge for continuous and facilitated biofluidic transport. In this paper, we have first introduced a novel interfacial microfluidic transport principle to drive three-dimensional liquid flows on a micropatterned superhydrophobic textile (MST) platform in a more autonomous and controllable manner. Specifically, the MST system utilizes the surface tension-induced Laplace pressure to facilitate the liquid motion along the hydrophilic yarn, in addition to the capillarity present in the fibrous structure. The fabrication of MST is simply accomplished by stitching hydrophilic cotton yarn into a superhydrophobic fabric substrate (contact angle 140 ± 3°), from which well-controlled wetting patterns are established for interfacial microfluidic operations. The geometric configurations of the stitched micropatterns, e.g., the lengths and diameters of the yarn and bundled arrangement, can all influence the transport process, which is investigated both experimentally and theoretically. Two operation modes, discrete and continuous transport, are also presented in detail. In addition, the gravitational effect as well as the droplet removal process have been also considered and quantitatively analysed during the transport process. As a demonstration, an MST design has been implemented on an artificial skin surface to collect and remove sweat in a highly efficient and facilitated means. The results have illustrated that the novel interfacial transport on the textile platform can be potentially extended to a variety of biofluidic collection and removal applications.

  13. Fabrication of a super-hydrophobic nanofibrous zinc oxide film surface by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Ding Bin [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); Fiber and Polymer Science, University of California, Davis, CA 95616 (United States)], E-mail: bding@ucdavis.edu; Ogawa, Tasuku [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); Kim, Jinho [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); SNT Ltd, Kawasaki 212-0054 (Japan); Fujimoto, Kouji [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); Shiratori, Seimei [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); SNT Ltd, Kawasaki 212-0054 (Japan)], E-mail: shiratori@appi.keio.ac.jp

    2008-03-03

    We report a new approach for fabricating a super-hydrophobic nanofibrous zinc oxide (ZnO) film surface. The pure poly(vinyl alcohol) (PVA) and composite PVA/ZnO nanofibrous films can be obtained by electrospinning the PVA and PVA/zinc acetate solutions, respectively. After the calcination of composite fibrous films, the inorganic fibrous ZnO films with a reduced fiber diameter were fabricated. The wettability of three kinds of fibrous film surfaces were modified with a simple coating of fluoroalkylsilane (FAS) in hexane. The resultant samples were characterized by field emission scanning electron microscopy (FE-SEM), water contact angle (WCA), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). It was found that the pure PVA fibrous films maintained the super-hydrophilic surface property even after the FAS modification. Additionally, the WCA of composite fibrous films was increased from 105 to 132 deg. with the coating of FAS. Furthermore, the surface property of inorganic ZnO fibrous films was converted from super-hydrophilic (WCA of 0 deg.) to super-hydrophobic (WCA of 165{sup o}) after the surface modification with FAS. Observed from XPS data, the hydrophobicity of FAS coated various film surfaces were found to be strongly affected by the ratio of fluoro:oxygen on the film surfaces.

  14. Designing superhydrophobic disordered arrays of fibers with hierarchical roughness and low-surface-energy

    Science.gov (United States)

    Rawal, Amit; Sharma, Sumit; Kumar, Vijay; Saraswat, Harshvardhan

    2016-12-01

    Hierarchical roughness and low surface energy are the main criteria for designing superhydrophobic surfaces with extreme water repellency. Herein, we present a step-wise approach to devise three-dimensional (3D) superhydrophobic disordered arrays of fibers in the form of nonwoven mats exhibiting hierarchical surface roughness and low surface energy. Key design parameters in the form of roughness factors at multiple length scales for 3D nonwoven mats have been quantified. The contact angles have been predicted for each of the wetting regimes that exists for nonwoven mats with predefined level of hierarchical surface roughness and surface energy. Experimental realization of superhydrophobic mats was attained by decorating the highly hydrophilic nonwoven viscose fibers with ZnO rods that effectively modulated the surface roughness at multiple length scales and subsequently, the surface energy was lowered using fluorocarbon treatment. Synergistic effects of hierarchical roughness and surface energy have systematically increased the static water contact angle of nonwoven mat (up to 164°) and simultaneously, lowered the roll-off angle (≈11°).

  15. Craniofacial fibrous dysplasia

    Directory of Open Access Journals (Sweden)

    Aakarsh Jhamb

    2012-01-01

    Full Text Available Fibrous dysplasia can present clinically in varied forms which may appear as collision of different pathologic processes. We report a rare case of craniofacial fibrous dysplasia with coexisting epithelial lined cyst and superimposed osteomyelitis with sequestrum formation. Its clinical features and management with possible hypotheses are described along with the post operative course. Pertinent literature has been reviewed with emphasis on pathogenesis of this unique occurrence.

  16. Wettability of natural superhydrophobic surfaces.

    Science.gov (United States)

    Webb, Hayden K; Crawford, Russell J; Ivanova, Elena P

    2014-08-01

    Since the description of the 'Lotus Effect' by Barthlott and Neinhuis in 1997, the existence of superhydrophobic surfaces in the natural world has become common knowledge. Superhydrophobicity is associated with a number of possible evolutionary benefits that may be bestowed upon an organism, ranging from the ease of dewetting of their surfaces and therefore prevention of encumbrance by water droplets, self-cleaning and removal of particulates and potential pathogens, and even to antimicrobial activity. The superhydrophobic properties of natural surfaces have been attributed to the presence of hierarchical microscale (>1 μm) and nanoscale (typically below 200 nm) structures on the surface, and as a result, the generation of topographical hierarchy is usually considered of high importance in the fabrication of synthetic superhydrophobic surfaces. When one surveys the breadth of data available on naturally existing superhydrophobic surfaces, however, it can be observed that topographical hierarchy is not present on all naturally superhydrophobic surfaces; in fact, the only universal feature of these surfaces is the presence of a sophisticated nanoscale structure. Additionally, several natural surfaces, e.g. those present on rose petals and gecko feet, display high water contact angles and high adhesion of droplets, due to the pinning effect. These surfaces are not truly superhydrophobic, and lack significant degrees of nanoscale roughness. Here, we discuss the phenomena of superhydrophobicity and pseudo-superhydrophobicity in nature, and present an argument that while hierarchical surface roughness may aid in the stability of the superhydrophobic effect, it is nanoscale surface architecture alone that is the true determinant of superhydrophobicity. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Electrospun nano-fibre mats with antibacterial properties from quaternised chitosan and poly(vinyl alcohol).

    Science.gov (United States)

    Ignatova, Milena; Starbova, Kirilka; Markova, Nadya; Manolova, Nevena; Rashkov, Iliya

    2006-09-04

    Nano-fibres containing quaternised chitosan (QCh) have been successfully prepared by electrospinning of QCh solutions mixed with poly(vinyl alcohol) (PVA). The average fibre diameter is in the range of 60-200 nm. UV irradiation of the composite electrospun nano-fibrous mats containing triethylene glycol diacrylate as cross-linking agent has resulted in stabilising of the nano-fibres against disintegration in water or water vapours. Microbiological screening has demonstrated the antibacterial activity of the photo-cross-linked electrospun mats against Staphylococcus aureus and Escherichia coli. The obtained nano-fibrous electrospun mats are promising for wound-healing applications.

  18. Superhydrophobic Porous Silicon Surfaces

    Directory of Open Access Journals (Sweden)

    Paolo NENZI

    2011-12-01

    Full Text Available In this paper, we present an inexpensive technique to produce superhydrophobic surfaces from porous silicon. Superhydrophobic surfaces are a key technology for their ability to reduce friction losses in microchannels and their self cleaning properties. The morphology of a p-type silicon wafer is modified by a electrochemical wet etch to produce pores with controlled size and distribution and coated with a silane hydrophobic layer. Surface morphology is characterized by means of scanning electron microscope images. Large contact angles are observed on such surfaces and the results are compared with classical wetting models (Cassie and Wenzel suggesting a mixed Wenzel-Cassie behavior. The presented technique represents a cost-effective means for friction reduction in microfluidic applications, such as lab-on-a-chip.

  19. Nanostructured Superhydrophobic Coatings

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-03-01

    This factsheet describes a research project that deals with the nanostructured superhydrophobic (SH) powders developed at ORNL. This project seeks to (1) improve powder quality; (2) identify binders for plastics, fiberglass, metal (steel being the first priority), wood, and other products such as rubber and shingles; (3) test the coated product for coating quality and durability under operating conditions; and (4) application testing and production of powders in quantity.

  20. Fluorine Based Superhydrophobic Coatings

    Directory of Open Access Journals (Sweden)

    Jean-Denis Brassard

    2012-05-01

    Full Text Available Superhydrophobic coatings, inspired by nature, are an emerging technology. These water repellent coatings can be used as solutions for corrosion, biofouling and even water and air drag reduction applications. In this work, synthesis of monodispersive silica nanoparticles of ~120 nm diameter has been realized via Stöber process and further functionalized using fluoroalkylsilane (FAS-17 molecules to incorporate the fluorinated groups with the silica nanoparticles in an ethanolic solution. The synthesized fluorinated silica nanoparticles have been spin coated on flat aluminum alloy, silicon and glass substrates. Functionalization of silica nanoparticles with fluorinated groups has been confirmed by Fourier Transform Infrared spectroscopy (FTIR by showing the presence of C-F and Si-O-Si bonds. The water contact angles and surface roughness increase with the number of spin-coated thin films layers. The critical size of ~119 nm renders aluminum surface superhydrophobic with three layers of coating using as-prepared nanoparticle suspended solution. On the other hand, seven layers are required for a 50 vol.% diluted solution to achieve superhydrophobicity. In both the cases, water contact angles were more than 150°, contact angle hysteresis was less than 2° having a critical roughness value of ~0.700 µm. The fluorinated silica nanoparticle coated surfaces are also transparent and can be used as paint additives to obtain transparent coatings.

  1. Producing superhydrophobic roof tiles

    Science.gov (United States)

    Carrascosa, Luis A. M.; Facio, Dario S.; Mosquera, Maria J.

    2016-03-01

    Superhydrophobic materials can find promising applications in the field of building. However, their application has been very limited because the synthesis routes involve tedious processes, preventing large-scale application. A second drawback is related to their short-term life under outdoor conditions. A simple and low-cost synthesis route for producing superhydrophobic surfaces on building materials is developed and their effectiveness and their durability on clay roof tiles are evaluated. Specifically, an organic-inorganic hybrid gel containing silica nanoparticles is produced. The nanoparticles create a densely packed coating on the roof tile surface in which air is trapped. This roughness produces a Cassie-Baxter regime, promoting superhydrophobicity. A surfactant, n-octylamine, was also added to the starting sol to catalyze the sol-gel process and to coarsen the pore structure of the gel network, preventing cracking. The application of ultrasound obviates the need to use volatile organic compounds in the synthesis, thereby making a ‘green’ product. It was also demonstrated that a co-condensation process effective between the organic and inorganic species is crucial to obtain durable and effective coatings. After an aging test, high hydrophobicity was maintained and water absorption was completely prevented for the roof tile samples under study. However, a transition from a Cassie-Baxter to a Wenzel state regime was observed as a consequence of the increase in the distance between the roughness pitches produced by the aging of the coating.

  2. A Thermochromic Superhydrophobic Surface

    Science.gov (United States)

    Cataldi, Pietro; Bayer, Ilker S.; Cingolani, Roberto; Marras, Sergio; Chellali, Ryad; Athanassiou, Athanassia

    2016-01-01

    Highly enhanced solid-state thermochromism is observed in regioregular poly(3-hexylthiophene), P3HT, when deposited on a superhydrophobic polymer-SiO2 nanocomposite coating. The conformal P3HT coating on the nanocomposite surface does not alter or reduce superhydrophicity while maintaining its reversible enhanced thermochromism. The polymeric matrix of the superhydrophobic surface is comprised of a blend of poly(vinylidene fluoride-co-hexafluoropropylene) copolymer and an acrylic adhesive. Based on detailed X-ray diffraction measurements, this long-lasting, repeatable and hysteresis-free thermochromic effect is attributed to the enhancement of the Bragg peak associated with the d-spacing of interchain directional packing (100) which remains unaltered during several heating-cooling cycles. We propose that the superhydrophobic surface confines π–π interchain stacking in P3HT with uniform d-spacing into its nanostructured texture resulting in better packing and reduction in face-on orientation. The rapid response of the system to sudden temperature changes is also demonstrated by water droplet impact and bounce back on heated surfaces. This effect can be exploited for embedded thin film temperature sensors for metal coatings. PMID:27301422

  3. A Thermochromic Superhydrophobic Surface

    Science.gov (United States)

    Cataldi, Pietro; Bayer, Ilker S.; Cingolani, Roberto; Marras, Sergio; Chellali, Ryad; Athanassiou, Athanassia

    2016-06-01

    Highly enhanced solid-state thermochromism is observed in regioregular poly(3-hexylthiophene), P3HT, when deposited on a superhydrophobic polymer-SiO2 nanocomposite coating. The conformal P3HT coating on the nanocomposite surface does not alter or reduce superhydrophicity while maintaining its reversible enhanced thermochromism. The polymeric matrix of the superhydrophobic surface is comprised of a blend of poly(vinylidene fluoride-co-hexafluoropropylene) copolymer and an acrylic adhesive. Based on detailed X-ray diffraction measurements, this long-lasting, repeatable and hysteresis-free thermochromic effect is attributed to the enhancement of the Bragg peak associated with the d-spacing of interchain directional packing (100) which remains unaltered during several heating-cooling cycles. We propose that the superhydrophobic surface confines π–π interchain stacking in P3HT with uniform d-spacing into its nanostructured texture resulting in better packing and reduction in face-on orientation. The rapid response of the system to sudden temperature changes is also demonstrated by water droplet impact and bounce back on heated surfaces. This effect can be exploited for embedded thin film temperature sensors for metal coatings.

  4. Adhesion behaviors on superhydrophobic surfaces.

    Science.gov (United States)

    Zhu, Huan; Guo, Zhiguang; Liu, Weimin

    2014-04-18

    The adhesion behaviors of superhydrophobic surfaces have become an emerging topic to researchers in various fields as a vital step in the interactions between materials and organisms/materials. Controlling the chemical compositions and topological structures via various methods or technologies is essential to fabricate and modulate different adhesion properties, such as low-adhesion, high-adhesion and anisotropic adhesion on superhydrophobic surfaces. We summarize the recent developments in both natural superhydrophobic surfaces and artificial superhydrophobic surfaces with various adhesions and also pay attention to superhydrophobic surfaces switching between low- and high-adhesion. The methods to regulate or translate the adhesion of superhydrophobic surfaces can be considered from two perspectives. One is to control the chemical composition and change the surface geometric structure on the surfaces, respectively or simultaneously. The other is to provide external stimulations to induce transitions, which is the most common method for obtaining switchable adhesions. Additionally, adhesion behaviors on solid-solid interfaces, such as the behaviors of cells, bacteria, biomolecules and icing on superhydrophobic surfaces are also noticeable and controversial. This review is aimed at giving a brief and crucial overview of adhesion behaviors on superhydrophobic surfaces.

  5. Strength of Fibrous Composites

    CERN Document Server

    Huang, Zheng-Ming

    2012-01-01

    "Strength of Fibrous Composites" addresses evaluation of the strength of a fibrous composite by using its constituent material properties and its fiber architecture parameters. Having gone through the book, a reader is able to predict the progressive failure behavior and ultimate strength of a fibrous laminate subjected to an arbitrary load condition in terms of the constituent fiber and matrix properties, as well as fiber geometric parameters. The book is useful to researchers and engineers working on design and analysis for composite materials. Dr. Zheng-Ming Huang is a professor at the School of Aerospace Engineering & Applied Mechanics, Tongji University, China. Mr. Ye-Xin Zhou is a PhD candidate at the Department of Mechanical Engineering, the University of Hong Kong, China.

  6. Optimization and characterization of poly(phthalazinone ether ketone) (PPEK) heat-resistant porous fiberous mat by electrospinning

    Science.gov (United States)

    Shi, R.; Bin, Y. Z.; Yang, W. X.; Wang, D.; Wang, J. Y.; Jian, X. G.

    2016-08-01

    Poly(phthalazinone ether ketone) (PPEK) is noted for its outstanding heat-resistance property and mechanical strength. A one-step electrospinning method was conducted to produce PPEK micro-nano porous fibrous mat. We gave emphasis study on the spinnability, optimized conditions, fibers' morphology, surface science and fracture mechanism. The uniform electrospun fibrous mat resulted from PPEK/chloroform binary system indicated that PPEK would be a prospective material to be applied in electrospinning. Addition of a small amount of non-solvent (ethanol) turned out to be advantageous to the reduction of fiber diameter and the alleviation of choking during spinning process. Organic salt (benzyltrimethylammonium chloride) was employed to increase the conductivity of solution for the formation of thin fiber. After trials, PPEK/chloroform/ethanol system with salt and PPEK/NMP system were taken as two optimized systems. These two systems showed different pore fraction in N2 adsorption test, and displayed different mechanical behaviors in uniaxial tension test. The fibrous mat from PPEK/chloroform/ethanol system showed a feature of ductile fracture with relatively low fracture strength but long fracture deformation, while the fibrous mat from PPEK/NMP system showed a feature of brittle fracture with small deformation but quite large fracture strength of ca. 6 MPa. Finally thermogravimetric analysis indicated that the resultant PPEK fibrous mat did not decompose until the temperature reached 478 °C, which qualified the resultant fibrous mat as a promising material used under high-temperature condition.

  7. Benign Fibrous Histiocytoma

    Directory of Open Access Journals (Sweden)

    Pushpa Varma

    2014-01-01

    Full Text Available Fibrous histiocytomas (FHs are mesenchymal tumors that may be benign or malignant. Ocular involvement by FHs is infrequent and primarily limited to the orbit. Rarely, FHs can also involve the conjunctiva and perilimbal area. We report the case of a 38-year-old male with lid, conjunctival, and neck FHs. The diagnosis was confirmed by histopathology.

  8. Calvarial malignant fibrous histiocytoma

    Directory of Open Access Journals (Sweden)

    Chhabra R

    2004-07-01

    Full Text Available Primary malignant fibrous histiocytoma (MFH of the central nervous system (CNS is uncommon. We report cases of two young patients of MFH arising from the cranial meninges and involving the adjacent skull and scalp. There was infiltration of the brain in one case. Both the lesions were excised and primary scalp repair was performed.

  9. Gastric Calcifying Fibrous Tumour

    Directory of Open Access Journals (Sweden)

    Tan Attila

    2006-01-01

    Full Text Available Intramucosal gastric tumours are most commonly found to be gastrointestinal stromal tumours or leiomyomas (smooth muscle tumours; however, a variety of other uncommon mesenchymal tumours can occur in the stomach wall. A rare benign calcifying fibrous tumour is reported and the endoscopic appearance, ultrasound findings and morphology are documented. A review of the literature found only two similar cases.

  10. The nature of fibrous dysplasia

    Directory of Open Access Journals (Sweden)

    Lemmer Johan

    2009-11-01

    Full Text Available Abstract Fibrous dysplasia has been regarded as a developmental skeletal disorder characterized by replacement of normal bone with benign cellular fibrous connective tissue. It has now become evident that fibrous dysplasia is a genetic disease caused by somatic activating mutation of the Gsα subunit of G protein-coupled receptor resulting in upregulation of cAMP. This leads to defects in differentiation of osteoblasts with subsequent production of abnormal bone in an abundant fibrous stroma. In addition there is an increased production of IL-6 by mutated stromal fibrous dysplastic cells that induce osteoclastic bone resorption.

  11. Water impacting on superhydrophobic macrotextures

    National Research Council Canada - National Science Library

    Gauthier, Anaïs; Symon, Sean; Clanet, Christophe; Quéré, David

    2015-01-01

    It has been recently shown that the presence of macrotextures on superhydrophobic materials can markedly modify the dynamics of water impacting them, and in particular significantly reduce the contact...

  12. Magnet-induced temporary superhydrophobic coatings from one-pot synthesized hydrophobic magnetic nanoparticles.

    Science.gov (United States)

    Fang, Jian; Wang, Hongxia; Xue, Yuhua; Wang, Xungai; Lin, Tong

    2010-05-01

    In this paper, we report on the production of superhydrophobic coatings on various substrates (e.g., glass slide, silicon wafer, aluminum foil, plastic film, nanofiber mat, textile fabrics) using hydrophobic magnetic nanoparticles and a magnet-assembly technique. Fe(3)O(4) magnetic nanoparticles functionalized with a thin layer of fluoroalkyl silica on the surface were synthesized by one-step coprecipitation of Fe(2+)/Fe(3+) under an alkaline condition in the presence of a fluorinated alkyl silane. Under a magnetic field, the magnetic nanoparticles can be easily deposited on any solid substrate to form a thin superhydrophobic coating with water contact angle as high as 172 degrees , and the surface superhydrophobicity showed very little dependence on the substrate type. The particulate coating showed reasonable durability because of strong aggregation effect of nanoparticles, but the coating layer can be removed (e.g., by ultrasonication) to restore the original surface feature of the substrates. By comparison, the thin particle layer deposited under no magnetic field showed much lower hydrophobicity. The main reason for magnet-induced superhydrophobic surfaces is the formation of nano- and microstructured surface features. Such a magnet-induced temporary superhydrophobic coating may have wide applications in electronic, biomedical, and defense-related areas.

  13. [Craniofacial fibrous dysplasia].

    Science.gov (United States)

    Couturier, A; Aumaître, O; Mom, T; Gilain, L; André, M

    2016-12-01

    Fibrous dysplasia of bone is a benign, uncommon, sporadic, congenital skeletal disorder resulting in deformity. This disease arises from activating somatic mutation in GNAS which encodes the α subunit of the G stimulatory protein associated with proliferation of undifferentiated osteogenic cells resulting in marrow fibrosis, abnormal matrix production, and stimulation of osteoclastic resorption upon overproduction of IL-6 observed in dysplastic cells. Fibrous dysplasia may be monostotic or polyostotic. This mutation affecting many tissues, café au lait skin macules and endocrinopathies (precocious puberty, hyperthyroidism, growth hormone excess, Cushing syndrome) may be associated in McCune-Albright syndrome, but also myxoma in Mazabraud syndrome or phosphate diabetes. Diagnosis of craniofacial fibrous dysplasia should be considered in the presence of headache, neuralgia, sensory disorders (vision, hearing, balance, smelling), functional disorders (nasal obstruction, nasolacrimal duct obstruction, non-matching occlusion), infectious complications (sinusitis, otitis, mastoiditis). Such symptoms should lead to perform craniofacial CT scan completed with MRI. Bone biopsy is not systematic. Surgical treatment is discussed in cases of nervous complication, facial deformity or active lesions. In case of pain resistant to conventional analgesics, intravenous bisphosphonates can be proposed. In non-responder patients, several case reports suggest the efficacy of a monoclonal antibody directed against the IL-6 receptor which requires to be confirmed by randomized studies.

  14. Cyanobacterial mats and stromatolites

    NARCIS (Netherlands)

    Stal, L.J.; Whitton, Brian A.

    2012-01-01

    Cyanobacteria are often the key organisms comprising microbial mats. They form dense micrometer-scale communities in which the full plethora of microbial metabolism can be present. Such mats are therefore excellent model systems and because of their analogy with Precambrian stromatolites they are al

  15. Fabrication of tunable superhydrophobic surfaces

    Science.gov (United States)

    Shiu, Jau-Ye; Kuo, Chun-Wen; Chen, Peilin

    2004-02-01

    Inspired by the water-repellent behavior of the micro- and nano-structured plant surfaces, superhydrophobic materials, with a water contact larger than 150 degree, have received a lot of research attentions recently. It has been suggested that contamination, oxidation and current conduction can be inhibited on such superhydrophobic surfaces, and the flow resistance in the microfluidic channels can also be reduced using super water-repellent materials. In order to prepare superhydrophobic materials, we have developed two simple approaches for fabricating tunable superhydrophobic surfaces using nanosphere lithography and plasma etching. In the first case, the polystyrene nanospheres were employed to create well-ordered rough surfaces covered by gold and alkylthiols. Using oxygen plasma treatment, the topmost surface area can be modified systematically, as the result the water contact angle on such surfaces can be tuned from 132 to 170 degree. The water contact angles measured on these surfaces can be modeled by the Cassie"s formulation without any adjustable parameter. In the second approach, thin films of Teflon were spin-coated on the substrate surfaces and treated by oxygen plasma. Superhydrophobic surfaces with water contact angle up to 170 degree were obtained by this approach. If the ITO glasses were used as the substrates, the hydrophobicity of the surface can be tuned by applying DC voltage. Water contact angle can be adjusted from 158 degree to 38 degree.

  16. Streaming potential of superhydrophobic microchannels.

    Science.gov (United States)

    Park, Hung Mok; Kim, Damoa; Kim, Se Young

    2016-12-09

    For the purpose of gaining larger streaming potential, it has been suggested to employ superhydrophobic microchannels with a large velocity slip. There are two kinds of superhydrophobic surfaces, one having a smooth wall with a large Navier slip coefficient caused by the hydrophobicity of the wall material, and the other having a periodic array of no- shear slots of air pockets embedded in a nonslip wall. The electrokinetic flows over these two superhydrophobic surfaces are modelled using the Navier-Stokes equation and convection-diffusion equations of the ionic species. The Navier slip coefficient of the first kind surfaces and the no-shear slot ratio of the second kind surfaces are similar in the sense that the volumetric flow rate increases as these parameter values increase. However, although the streaming potential increases monotonically with respect to the Navier slip coefficient, it reaches a maximum and afterward decreases as the no-shear ratio increases. The results of the present investigation imply that the characterization of superhydrophobic surfaces employing only the measurement of volumetric flow rate against pressure drop is not appropriate and the fine structure of the superhydrophobic surfaces must be verified before predicting the streaming potential and electrokinetic flows accurately.

  17. Essential Oil Bioactive Fibrous Membranes Prepared via Coaxial Electrospinning.

    Science.gov (United States)

    Yao, Zhi-Cheng; Chen, Si-Cong; Ahmad, Zeeshan; Huang, Jie; Chang, Ming-Wei; Li, Jing-Song

    2017-06-01

    A novel antimicrobial composite material was prepared by encapsulating orange essential oil (OEO) in zein prolamine (ZP) via the coaxial electrospinning (ES) technique. By manipulating process parameters, the morphological features of ZP/OEO fibers were modulated. Fine fibers with diameters ranging from 0.7 to 2.3 μm were obtained by regulating ZP solution concentration and process parameters during the ES process. Optimal loading capacity (LC) and encapsulation efficiency (EE) of OEO in fibrous ZP mats were determined to be 22.28% and 53.68%, respectively, and were achieved using a 35 w/v% ZP ES solution. The encapsulation of OEO was found to be reliant on ZP solution concentration (the enveloping medium). SEM analysis indicates the surface morphology of ZP/OEO electrospun fibers is dependent on ZP solution loading volume, with lower ZP concentrations yielding defective fibrous structures (for example, beaded and spindled-string like morphologies). Furthermore, this loading volume also influences OEO LC, EE, mat water contact angle and oil retention. CCK-8 assay and cell morphology assessment (HEK293T cells) indicate no significant change with electrospun ZP and ZP/OEO fibrous membranes over an 8 h period. Antimicrobial activity assessment using Escherichia coli, suggests composite nonwovens possess sterilization properties; elucidating potential application in active food packaging, food preservation and therefore sustainability. © 2017 Institute of Food Technologists®.

  18. Glutaraldehyde vapor cross-linked nanofibrous PVA mat with in situ formed silver nanoparticles.

    Science.gov (United States)

    Destaye, Addisu Getachew; Lin, Cheng-Keng; Lee, Cheng-Kang

    2013-06-12

    Polyvinyl alcohol (PVA) nanofibrous mat can be easily prepared via electrospinning its aqueous solution. However, the obtained nanofibrous mat is instantaneously dissolved in water. Therefore, rendering the environmentally friendly nanofibrous mat water insoluble by cross-linking mechanism is of great interest. The electrospun PVA nanofibrous mat with an average fiber diameter of ca. 400 nm could be effectively cross-linked by glutaraldehyde vapor at room temperature. The cross-linking not only resulted in a water-insoluble nanofibrous mat but also generated an excess amount of unreacted aldehyde functional groups that could reduce silver salts into silver nanoparticles. The in situ formed silver nanoparticles along the fibrous surface showed excellent antimicrobial activity against Escherichia coli. The vapor cross-linked nanofibrous mat shows a high potential to be used for efficiently capturing and killing pathogenic bacteria.

  19. Recent Advances in Superhydrophobic Electrodeposits

    Directory of Open Access Journals (Sweden)

    Jason Tam

    2016-03-01

    Full Text Available In this review, we present an extensive summary of research on superhydrophobic electrodeposits reported in the literature over the past decade. As a synthesis technique, electrodeposition is a simple and scalable process to produce non-wetting metal surfaces. There are three main categories of superhydrophobic surfaces made by electrodeposition: (i electrodeposits that are inherently non-wetting due to hierarchical roughness generated from the process; (ii electrodeposits with plated surface roughness that are further modified with low surface energy material; (iii composite electrodeposits with co-deposited inert and hydrophobic particles. A recently developed strategy to improve the durability during the application of superhydrophobic electrodeposits by controlling the microstructure of the metal matrix and the co-deposition of hydrophobic ceramic particles will also be addressed.

  20. Influence of Flow on Longevity of Superhydrophobic Coatings

    Science.gov (United States)

    Samaha, Mohamed A.; Vahedi Tafreshi, Hooman; Gad-El-Hak, Mohamed

    2012-11-01

    Previous studies have demonstrated the capability of superhydrophobic surfaces to produce slip flow and drag reduction, which properties hold considerable promise for a broad range of applications. However, in order to implement such surfaces for practical utilizations, environmental factors such as water movement over the surface must be observed and understood. In this work, experiments were carried out to present a proof-of-concept study on the impact of flow on longevity of polystyrene fibrous coatings. The time-dependent hydrophobicity of a submerged coating in a pressure vessel was determined while exposing the coating to a rudimentary wall-jet flow. Rheological studies were also performed to determine the effect of the flow on drag reduction. The results show that the longevity of the surface deteriorates by increasing the flowrate. The flow appears to enhance the dissolution of air into water, which leads to a loss of drag-reduction.

  1. Thermocapillary Flow on Superhydrophobic Surfaces

    CERN Document Server

    Baier, Tobias; Hardt, Steffen

    2010-01-01

    A liquid in Cassie-Baxter state above a structured superhydrophobic surface is ideally suited for surface driven transport due to its large free surface fraction in close contact to a solid. We investigate thermal Marangoni flow over a superhydrophobic array of fins oriented parallel or perpendicular to an applied temperature gradient. In the Stokes limit we derive an analytical expression for the bulk flow velocity above the surface and compare it with numerical solutions of the Navier-Stokes equation. Even for moderate temperature gradients comparatively large flow velocities are induced, suggesting to utilize this principle for microfluidic pumping.

  2. Solitary fibrous tumor

    Directory of Open Access Journals (Sweden)

    Manlio Mencoboni

    2010-12-01

    Full Text Available Solitary fibrous tumor (SFT is a rare mesenchymal neoplasm which may be found everywhere in the body. It is now distinguished into two forms, pleural and extrapleural, which morphologically resemble each other. Abdomi­nal localizations are quite rare, with 10 cases only reported in bladder; rarely they can be source of paraneoplastic syndromes (i.e., hypoglycemia secondary to insulin-like growth factor. In April 2006 a 74-year-old white male presented with chills, diaphoresis and acute abdominal pain with hematuria. At admission in emergency he underwent an abdominal X-ray (no pathological findings and an ultrasound examination of the kidneys and urinary tract, which revealed a pelvic hyperechogenic neoformation measuring approximately 10¥8¥7 cm, compressing the bladder. Blood chemistry at admission revealed only a mild neutrophilic leucocytosis (WBC 16600, N 80%, L 11%, elevated fibrinogen and ESR, and hypoglycemia (38 mg/dL. Macro­scopic hematuria was evident, while urinocolture was negative. Contrast enhanced CT scan of the abdomen and pelvic region revealed a large round neoformation dislocating the bladder, with an evident contrast-enhanced periphery and a central necrotic area. Continuous infusion of glucose 5% solution was necessary in order to maintain blood glucose levels above 50 mg/dL. The patient underwent complete surgical resection of an ovoidal mass coated by adipose tissue, with well delimited margins; histological findings were consistent with solitary fibrous tumor (SFT. Hypoglycemia resolved completely with removal of the growth. In this case report we describe a SFT growing in the bladder, a quite rare localization, which presented a unique hypoglycemia. In contrast to the majority of cases reported in the literature, the behavior of this SFT was not aggressive, and, since the patient is still alive, surgical resection was considered conclusive.

  3. Facile preparation of super durable superhydrophobic materials.

    Science.gov (United States)

    Wu, Lei; Zhang, Junping; Li, Bucheng; Fan, Ling; Li, Lingxiao; Wang, Aiqin

    2014-10-15

    The low stability, complicated and expensive fabrication procedures seriously hinder practical applications of superhydrophobic materials. Here we report an extremely simple method for preparing super durable superhydrophobic materials, e.g., textiles and sponges, by dip coating in fluoropolymers (FPs). The morphology, surface chemical composition, mechanical, chemical and environmental stabilities of the superhydrophobic textiles were investigated. The results show how simple the preparation of super durable superhydrophobic textiles can be! The superhydrophobic textiles outperform their natural counterparts and most of the state-of-the-art synthetic superhydrophobic materials in stability. The intensive mechanical abrasion, long time immersion in various liquids and repeated washing have no obvious influence on the superhydrophobicity. Water drops are spherical in shape on the samples and could easily roll off after these harsh stability tests. In addition, this simple dip coating approach is applicable to various synthetic and natural textiles and can be easily scaled up. Furthermore, the results prove that a two-tier roughness is helpful but not essential with regard to the creation of super durable superhydrophobic textiles. The combination of microscale roughness of textiles and materials with very low surface tension is enough to form super durable superhydrophobic textiles. According to the same procedure, superhydrophobic polyurethane sponges can be prepared, which show high oil absorbency, oil/water separation efficiency and stability. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Anthraquinone dyes for superhydrophobic cotton.

    Science.gov (United States)

    Salabert, J; Sebastián, R M; Vallribera, A

    2015-09-28

    Water-repellent, self-cleaning and stain resistant textiles are of interest for industrial applications. Anthraquinone reactive dyes were covalently grafted onto cotton fabric surfaces obtaining bright colors with good wash-fastness properties and giving rise to breathable superhydrophobic textiles with self-cleaning properties.

  5. Superhydrophobic materials for biomedical applications.

    Science.gov (United States)

    Falde, Eric J; Yohe, Stefan T; Colson, Yolonda L; Grinstaff, Mark W

    2016-10-01

    Superhydrophobic surfaces are actively studied across a wide range of applications and industries, and are now finding increased use in the biomedical arena as substrates to control protein adsorption, cellular interaction, and bacterial growth, as well as platforms for drug delivery devices and for diagnostic tools. The commonality in the design of these materials is to create a stable or metastable air layer at the material surface, which lends itself to a number of unique properties. These activities are catalyzing the development of new materials, applications, and fabrication techniques, as well as collaborations across material science, chemistry, engineering, and medicine given the interdisciplinary nature of this work. The review begins with a discussion of superhydrophobicity, and then explores biomedical applications that are utilizing superhydrophobicity in depth including material selection characteristics, in vitro performance, and in vivo performance. General trends are offered for each application in addition to discussion of conflicting data in the literature, and the review concludes with the authors' future perspectives on the utility of superhydrophobic biomaterials for medical applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Flow in channels with superhydrophobic trapezoidal textures

    CERN Document Server

    Nizkaya, Tatiana V; Vinogradova, Olga I

    2013-01-01

    Superhydrophobic one-dimensional surfaces reduce drag and generate transverse hydrodynamic phenomena by combining hydrophobicity and roughness to trap gas bubbles in a microscopic textures. Recent work in this area has focused on specific cases of superhydrophobic stripes. Here we study theoretically and numerically the hydrodynamic flow in a channel with a superhydrophobic trapezoidal texture. These allow us to evaluate the drag reduction and anisotropy of the flow for various trapezoidal reliefs. Our results provide a framework for the rational design of superhydrophobic surfaces for microfluidic applications.

  7. Fabrication of recyclable superhydrophobic cotton fabrics

    Science.gov (United States)

    Han, Sang Wook; Park, Eun Ji; Jeong, Myung-Geun; Kim, Il Hee; Seo, Hyun Ook; Kim, Ju Hwan; Kim, Kwang-Dae; Kim, Young Dok

    2017-04-01

    Commercial cotton fabric was coated with SiO2 nanoparticles wrapped with a polydimethylsiloxane (PDMS) layer, and the resulting material surface showed a water contact angle greater than 160°. The superhydrophobic fabric showed resistance to water-soluble contaminants and maintained its original superhydrophobic properties with almost no alteration even after many times of absorption-washing cycles of oil. Moreover, superhydrophobic fabric can be used as a filter to separate oil from water. We demonstrated a simple method of fabrication of superhydrophobic fabric with potential interest for use in a variety of applications.

  8. MAT FOR LEPTOSPIROSIS DIAGNOSIS

    Directory of Open Access Journals (Sweden)

    Esti Rahardianingtyas.

    2014-06-01

    Full Text Available Leptospirosis is a disease caused by bacterial infection leptospira interrogans.Leptospira bacteria is a spiral bacterium with solid strands with two flagella periplasmik.Septicaemic phase patient samples taken from the blood and cerebrospinal fluid, whereassamples taken at phase immune extracted from urine. The diagnosis of leptospirosis occurdirectly or indirectly. Diagnosis is done by directly isolate and identify the causative agents ofthe agent. Diagnosis is done indirectly by detecting specific antibodies from the patient's body.Gold Standard of the diagnosis of leptospirosis is MAT. Mat made by reacting antibodies toleptospira antigen. Positive results seen with clump formed.Key words: Leptospirosis, Leptospirosis Diagnostic, MAT (Microscopic Agglutination Test Leptospirosis merupakan penyakit yang disebabkan karena infeksi bakteri leptospirainterrogans. Bakteri leptospira merupakan bakteri spiral dengan untaian yang padat dengan duaflagella periplasmik. Sampel pasien pada fase septicaemic diambil dari darah dan cairanserebrospinal, sedangkan sampel yang diambil pada fase immune diambil dari urine. Diagnosisleptospirosis dilakukan secara langsung maupun tidak langsung. Diagnosis secara langsungdilakukan dengan cara mengisolasi agen penyebab dan mengidentifikasi agen tersebut. Diagnosissecara tidak langsung dilakukan dengan cara mendeteksi antibodi spesiflk dari dalam tubuhpasien. Gold Standart dari diagnosis leptospirosis adalah MAT. Mat dilakukan dengan caramereaksikan antibodi dengan antigen leptospira. Hasil positif dilihat dengan terbentuk gumpalanagglutinasiKata kunci: Leptospirosis, Leptospira, Leptospirosis Diagnosis.

  9. MAT 126 ASH Course Tutorial / Tutorialoutlet

    OpenAIRE

    stylia

    2015-01-01

    For more course tutorials visit www.tutorialoutlet.com   MAT 126 Week 1 DQ 1 (Ash) MAT 126 Week 1 Quiz (Ash) MAT 126 Week 1 Written Assignment (Arithmetic and geometric sequence) (Ash) MAT 126 Week 2 DQ 1 (Ash) MAT 126 Week 2 DQ 2 (Ash) MAT 126 Week 2 Assignment Is It Fat Free (Ash) MAT 126 Week 2 Quiz (Ash) MAT 126 Week 3 DQ 1 (Ash) MAT 126 Week 3 DQ 2 (Ash) MAT 126 Week 3 Assignment Quadratic Equations (Ash) MAT 126 Week 3 Quiz (Ash) MAT 126...

  10. Superhydrophobic laser ablated PTFE substrates

    Energy Technology Data Exchange (ETDEWEB)

    Falah Toosi, Salma; Moradi, Sona [Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, BC, V6T 1Z3 (Canada); Kamal, Saeid [Laboratory for Advanced Spectroscopy and Imaging research (LASIR) Chemistry Department, The University of British Columbia, Vancouver, BC, V6T 1Z3 (Canada); Hatzikiriakos, Savvas G., E-mail: savvas.hatzi@ubc.ca [Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, BC, V6T 1Z3 (Canada)

    2015-09-15

    Highlights: • Uniaxial and biaxial patterns fabricated on PTFE surface are responsible for superhydrophobic behavior of the surface. • Biaxial scan artificially creates high level of dual scale roughness on the PTFE surface with high contact angles (CAs) and low contact angle hysteresis (CAH) similar in all directions. • Contact angle of biaxially scanned surfaces can be as high as 170° and their contact angle hysteresis can reach as low as 3°. - Abstract: The effect of femtosecond laser irradiation process parameters (fluence, scanning speed and beam overlap) on the wettability of the resulted micro/nano-patterned morphologies on polytetrafluoroethylene is studied in detail. Several distinctly different micro/nano-patterns were fabricated including uniaxial and biaxial patterns. In particular, using biaxial scanning well defined pillared morphology was fabricated. The wettability analysis of the biaxially scanned samples revealed enhanced superhydrophobicity exhibiting high contact angles and low contact angle hysteresis.

  11. Diazotrophic microbial mats

    NARCIS (Netherlands)

    Severin, I.; Stal, L.J.; Seckbach, J.; Oren, A.

    2010-01-01

    Microbial mats have been the focus of scientific research for a few decades. These small-scale ecosystems are examples of versatile benthic communities of microorganisms, usually dominated by phototrophic bacteria (e.g., Krumbein et al., 1977; Jørgensen et al., 1983). They develop as vertically stra

  12. Juhtlaused / Mats Nõges

    Index Scriptorium Estoniae

    Nõges, Mats, 1879-1973

    2011-01-01

    19. sajandi ja 20. sajandi alguse demograafilisi seisukohti väljendavad teesid Tartu ülikooli arstiteaduskonnale arstiteaduse doktori astme omandamiseks esitatud väitekirjast: Mats Nõges. Rahwamuutused Wiljandi Maakonnas 1801.- 1923. a. = Bevölkerungsbewegung im Kreise Fellin in Jahren 1801-1923. Demograafiline töö. Tartu, 1925

  13. Lift and Drag Measurements of Superhydrophobic Hydrofoils

    Science.gov (United States)

    Sur, Samrat; Kim, Jeong-Hyun; Rothstein, Jonathan

    2015-11-01

    For several years, superhydrophobic surfaces which are chemically hydrophobic with micron or nanometer scale surface features have been considered for their ability to reduce drag and produce slip in microfluidic devices. More recently it has been demonstrated that superhydrophobic surfaces reduce friction coefficient in turbulent flows as well. In this talk, we will consider that modifying a hydrofoil's surface to make it superhydrophobic has on the resulting lift and drag measurements over a wide range of angles of attack. Experiments are conducted over the range of Reynolds numbers between 10,000hydrofoil is made superhydrophobic. The hydrofoils are coated Teflon that has been hot embossed with a 325grit stainless steel woven mesh to produce a regular pattern of microposts. In addition to fully superhydrophobic hydrofoils, selectively coated symmetrical hydrofoils will also be examined to study the effect that asymmetries in the surface properties can have on lift and drag. Partially funded by NSF CBET-1334962.

  14. Metallic superhydrophobic surfaces via thermal sensitization

    Science.gov (United States)

    Vahabi, Hamed; Wang, Wei; Popat, Ketul C.; Kwon, Gibum; Holland, Troy B.; Kota, Arun K.

    2017-06-01

    Superhydrophobic surfaces (i.e., surfaces extremely repellent to water) allow water droplets to bead up and easily roll off from the surface. While a few methods have been developed to fabricate metallic superhydrophobic surfaces, these methods typically involve expensive equipment, environmental hazards, or multi-step processes. In this work, we developed a universal, scalable, solvent-free, one-step methodology based on thermal sensitization to create appropriate surface texture and fabricate metallic superhydrophobic surfaces. To demonstrate the feasibility of our methodology and elucidate the underlying mechanism, we fabricated superhydrophobic surfaces using ferritic (430) and austenitic (316) stainless steels (representative alloys) with roll off angles as low as 4° and 7°, respectively. We envision that our approach will enable the fabrication of superhydrophobic metal alloys for a wide range of civilian and military applications.

  15. Superhydrophobic Membrane Contactor for Acid Gas Removal

    Science.gov (United States)

    Faiqotul Himma, Nurul; Gede Wenten, I.

    2017-07-01

    Gas-liquid membrane contactor has gained a great attention as an alternative to conventional absorption columns in acid gas removal from natural gas or post-combustion. The membrane contactor offers high mass transfer area and excellent operational flexibility. However, hydrophobic microporous membranes commonly used are still susceptible to wetting by liquid absorbents, leading to the deterioration of absorption performance in long-term operation. Therefore, many studies were recently directed to improve the membrane wetting resistant by endowing superhydrophobicity. This article then presents a review on superhydrophobic membrane development and its application for acid gas removal using membrane contactor. An overview of gas-liquid membrane contactor is firstly presented, followed by the preparation of superhydrophobic membranes. The performances of superhydrophobic membranes in acid gas absorption are then discussed, and the recommendation for future research is finally outlined. This review may provide an insight into the further development of superhydrophobic membrane contactor.

  16. Wettability Switching Techniques on Superhydrophobic Surfaces

    Directory of Open Access Journals (Sweden)

    Verplanck Nicolas

    2007-01-01

    Full Text Available Abstract The wetting properties of superhydrophobic surfaces have generated worldwide research interest. A water drop on these surfaces forms a nearly perfect spherical pearl. Superhydrophobic materials hold considerable promise for potential applications ranging from self cleaning surfaces, completely water impermeable textiles to low cost energy displacement of liquids in lab-on-chip devices. However, the dynamic modification of the liquid droplets behavior and in particular of their wetting properties on these surfaces is still a challenging issue. In this review, after a brief overview on superhydrophobic states definition, the techniques leading to the modification of wettability behavior on superhydrophobic surfaces under specific conditions: optical, magnetic, mechanical, chemical, thermal are discussed. Finally, a focus on electrowetting is made from historical phenomenon pointed out some decades ago on classical planar hydrophobic surfaces to recent breakthrough obtained on superhydrophobic surfaces.

  17. Dynamic Defrosting on Nanostructured Superhydrophobic Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Boreyko, Jonathan B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Srijanto, Bernadeta R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science & Engineering; Nguyen, Trung Dac [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Center for Computational Sciences; Vega, Carlos [Univ. Complutense Madrid (Spain). Dept. de Quimica Fisica; Fuentes-Cabrera, Miguel [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computer Science and Mathematics Division; Collier, C. Patrick [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)

    2013-07-03

    Water suspended on chilled superhydrophobic surfaces exhibits delayed freezing; however, the interdrop growth of frost through subcooled condensate forming on the surface seems unavoidable in humid environments. It is therefore of great practical importance to determine whether facile defrosting is possible on superhydrophobic surfaces. Here in this paper, we report that nanostructured superhydrophobic surfaces promote the growth of frost in a suspended Cassie state, enabling its dynamic removal upon partial melting at low tilt angles (<15°). The dynamic removal of the melting frost occurred in two stages: spontaneous dewetting followed by gravitational mobilization. This dynamic defrosting phenomenon is driven by the low contact angle hysteresis of the defrosted meltwater relative to frost on microstructured superhydrophobic surfaces, which forms in the impaled Wenzel state. Dynamic defrosting on nanostructured superhydrophobic surfaces minimizes the time, heat, and gravitational energy required to remove frost from the surface, and is of interest for a variety of systems in cold and humid environments.

  18. Quaternized chitosan/κ-carrageenan/caffeic acid-coated poly(3-hydroxybutyrate) fibrous materials: Preparation, antibacterial and antioxidant activity.

    Science.gov (United States)

    Ignatova, Milena; Manolova, Nevena; Rashkov, Iliya; Markova, Nadya

    2016-11-20

    Novel fibrous materials with antioxidant and antibacterial properties from poly(3-hydroxybutyrate) (PHB), quaternized chitosan (QCh), κ-carrageenan (Car) and caffeic acid (CA) were obtained. These materials were prepared by applying electrospinning or electrospinning in conjunction with dip-coating and polyelectrolyte complex (PEC) formation. It was found that the CA release depended on the fiber composition. X-ray diffraction analysis (XRD) and differential scanning calorimetry (DSC) revealed that CA incorporated in the fibers was in the amorphous state, whereas CA included in the coating was in the crystalline state. In contrast to the neat PHB mats, the CA-containing mats and the PEC QCh/Car-coated mats were found to kill the Gram-positive bacteria S. aureus and the Gram-negative bacteria E. coli and were effective in suppressing the adhesion of pathogenic bacteria S. aureus. Enhancement of the antioxidant activity of the fibrous materials containing both CA and QCh/Car coating was observed.

  19. General Deposition of Metal-Organic Frameworks on Highly Adaptive Organic-Inorganic Hybrid Electrospun Fibrous Substrates.

    Science.gov (United States)

    Liu, Chang; Wu, Yi-Nan; Morlay, Catherine; Gu, Yifan; Gebremariam, Binyam; Yuan, Xiao; Li, Fengting

    2016-02-01

    Electrospun nanofibrous mats are ideal substrates for metal-organic frameworks (MOFs) crystal deposition because of their specific structural parameters and chemical tenability. In this work, we utilized organic-inorganic hybrid electrospun fibrous mats as support material to study the deposition of various MOF particles. HKUST-1 and MIL-53(Al) were produced through solvothermal method, while ZIF-8 and MIL-88B(Fe) were prepared using microwave-induced heating method. The synthesis procedure for both methods were simple and effective because the hybrid nanofibrous mats showed considerable affinity to MOF particles and could be used without additional modifications. The obtained MOF composites exhibited effective incorporation between MOF particles and the porous substrates. MIL-53(Al) composite was applied as fibrous sorbent and showed enhanced adsorption capacity and removal rate, as well as easier operation, compared with thepowdered sample. Moreover, MIL-53(Al) composite was easier to be regenerated compared with powder form.

  20. On Matlis dualizing modules

    Directory of Open Access Journals (Sweden)

    Edgar E. Enochs

    2002-01-01

    Full Text Available We consider rings admitting a Matlis dualizing module E. We argue that if R admits two such dualizing modules, then a module is reflexive with respect to one if and only if it is reflexive with respect to the other. Using this fact we argue that the number (whether finite or infinite of distinct dualizing modules equals the number of distinct invertible (R,R-bimodules. We show by example that this number can be greater than one.

  1. Dynamic contact angle measurements on superhydrophobic surfaces

    Science.gov (United States)

    Kim, Jeong-Hyun; Kavehpour, H. Pirouz; Rothstein, Jonathan P.

    2015-03-01

    In this paper, the dynamic advancing and receding contact angles of a series of aqueous solutions were measured on a number of hydrophobic and superhydrophobic surfaces using a modified Wilhelmy plate technique. Superhydrophobic surfaces are hydrophobic surfaces with micron or nanometer sized surface roughness. These surfaces have very large static advancing contact angles and little static contact angle hysteresis. In this study, the dynamic advancing and dynamic receding contact angles on superhydrophobic surfaces were measured as a function of plate velocity and capillary number. The dynamic contact angles measured on a smooth hydrophobic Teflon surface were found to obey the scaling with capillary number predicted by the Cox-Voinov-Tanner law, θD3 ∝ Ca. The response of the dynamic contact angle on the superhydrophobic surfaces, however, did not follow the same scaling law. The advancing contact angle was found to remain constant at θA = 160∘, independent of capillary number. The dynamic receding contact angle measurements on superhydrophobic surfaces were found to decrease with increasing capillary number; however, the presence of slip on the superhydrophobic surface was found to result in a shift in the onset of dynamic contact angle variation to larger capillary numbers. In addition, a much weaker dependence of the dynamic contact angle on capillary number was observed for some of the superhydrophobic surfaces tested.

  2. The durability of superhydrophobic films

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shing-Dar, E-mail: sdwang@yuntech.edu.tw; Jiang, Ya-Syuan

    2015-12-01

    Graphical abstract: - Highlights: • Heat treatment of a superhydrophobic film at 200 °C for 24 h induces Si−OH networks. • Electric field aging of a superhydrophobic film induces hydroxyl chains. • More SiO{sub 2} groups than OSi(CH{sub 3}){sub 3} groups were removed during water impact test. • Molecular simulations of a superhydrophobic film approximate XPS’ analysis. - Abstract: Superhydrophobic sol–gels, spin-coated on a glass substrate, were synthesized by varying the hexamethyldisilazane/tetraethoxysilane ratio (Ratio) from 1 to 2. A simple heat treatment at 200 °C for 2 h, an additional prolonged heat treatment at 200 °C for 24 h, and an additional prolonged electric field aging for 24 h with specimens connected to the positive or negative electrodes were performed. The specimens were subjected to a water impact test (WIT) for 2 h, and water contact angle (WCA) and sliding angle (SA) were measured before and after WIT. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy were employed to analyze the variations of elements and functional groups in the hydrophobic film before and after the WIT. The variations of area ratio of XPS deconvolution peaks showed that during the WIT more SiO{sub 2} groups than OSi(CH{sub 3}){sub 3} groups were washed away in the hydrophobic film. Molecular simulation provided a complete image showing the molecules constituting the surface of the hydrophobic film before and after WIT. The additional heat and electric field treatment induced Si−OH network and vertical arrays of hydroxyl chains, respectively, which exerted viscous forces on the water drops but also mitigated the impact strength of the water column. Hence, before WIT, the specimen with a simple heat treatment at 200 °C for 2 h exhibited the highest WCA and lowest SA. After the WIT at a Ratio of 1.6, 1.8, and 2, SA increased in the following order: additional 24-h heat-treated specimen < electric field aging negative

  3. An easy route to make superhydrophobic surface

    Science.gov (United States)

    Panda, Kalpataru; Kumar, N.; Polaki, S. R.; Panigrahi, B. K.

    2012-06-01

    Superhydrophobic films with excellent flexibility have been fabricated on silicon surface, generated by means of a chemical galvanic cell route, within a short span of 10 sec. The results show a water contact angle of 155° (superhydrophobic) for the chemically modified silicon surface while it is 63° (hydrophilic) in pure silicon substrate. The surface roughness increases with well ordered protrusions after the chemical treatment. Surface roughness and low surface energy are ascribed for the superhydrophobic behavior of these chemically modified silicon surfaces.

  4. Rapid Drop Dynamics During Superhydrophobic Condensation

    Science.gov (United States)

    Zhang, Xiaodong; Boreyko, Jonathan; Chen, Chuan-Hua

    2008-11-01

    Rapid drop motion is observed on superhydrophobic surfaces during condensation; condensate drops with diameter of order 10 μm can move at above 100G and 0.1 m/s. When water vapor condenses on a horizontal superhydrophobic surface, condensate drops move in a seemingly random direction. The observed motion is attributed to the energy released through coalescence of neighboring condensate drops. A scaling analysis captured the initial acceleration and terminal velocity. Our work is a step forward in understanding the dynamics of superhydrophobic condensation occurring in both natural water-repellant plants and engineered dropwise condensers.

  5. ELECTROSPRAYING/ELECTROSPINNING OF POLY(y-STEARYL-L-GLUTAMATE):FORMATION OF SURFACES WITH SUPERHYDROPHOBICITY

    Institute of Scientific and Technical Information of China (English)

    Lin-jun Shao; Jian Wu; Zhi-kang Xu

    2009-01-01

    Electrospraying/electrospinning of poly(y-stearyl-L-glutamate) (PSLG) was investigated on a series solutions with different concentrations in chloroform.Field emission scanning electron microscopy (FESEM) and attenuated total reflectance Fourier transform infrared spectroscopy (FT-IR/ATR) were used to characterize the morphology and structure of the electrosprayed/electrospun polypeptide mats.It was found that electrospraying of PSLG with concentrations lower than 16 wt% afforded beads,while microfibers could be electrospun at the concentration of 22 wt%.The hydrophobieity of the electrosprayed/electrospun PSLG mats was investigated with static water contact angle (WCA) and tilt angle measurements.It was demonstrated that the superhydrophobic surfaces of PSLG with WCAs and tilt angles in the ranges of 150°-170°and16.5°-4.2°,respectively,were obtained through electrospraying/electrospinning process.

  6. Superhydrophobic porous networks for enhanced droplet shedding

    Science.gov (United States)

    Liu, Yahua; Wang, Zuankai

    2016-09-01

    Recent research has shown that the use of submillimeter-scale tapered post arrays could generate the so-called pancake bouncing, which is characterized by the fast shedding of impinging drops from the surface in a pancake shape without undergoing the retraction stage as observed on conventional superhydrophobic surfaces. Despite this exciting discovery, the fabrication of this unique superhydrophobic surface with tapered post arrays involves complex processes, hindering its wide applications in practical sectors. Here, we report on the facile strategy to prepare a new hierarchical multilayered superhydrophobic surface directly from commercially available porous matrix that allows for efficient drop shedding. Further study shows that the enhanced drop mobility observed on such a surface is attributed to the synergistic cooperation of hierarchical structures endowing an adequate energy storage and effective energy release. The facile fabrication of superhydrophobic surface with enhanced drop mobility may find many practical applications including anti-icing, dropwise condensation and self-cleaning.

  7. Reinigung superhydrophober Oberflächen

    OpenAIRE

    Dallmann, Silke

    2011-01-01

    The unique surface structure of the lotus leaf in combination with hydrophobic epicuticular wax crystalloids results in extreme water repellency and self-cleaning properties. In recent years biomimetic superhydrophobic surfaces have been fabricated by mimicking the structure of the lotus leaf. The biggest problem of the fine surface roughness is the sensitivity to oily contaminants and mechanical stress which limit the application of technical superhydrophobic sur...

  8. Creep of fibrous composite materials

    DEFF Research Database (Denmark)

    Lilholt, Hans

    1985-01-01

    Models are presented for the creep behaviour of fibrous composite materials with aligned fibres. The models comprise both cases where the fibres remain rigid in a creeping matrix and cases where the fibres are creeping in a creeping matrix. The treatment allows for several contributions to the cr......Models are presented for the creep behaviour of fibrous composite materials with aligned fibres. The models comprise both cases where the fibres remain rigid in a creeping matrix and cases where the fibres are creeping in a creeping matrix. The treatment allows for several contributions...... such as Ni + W-fibres, high temperature materials such as Ni + Ni3Al + Cr3C2-fibres, and medium temperature materials such as Al + SiC-fibres. For the first two systems reasonable consistency is found for the models and the experiments, while for the third system too many unquantified parameters exist...

  9. Self-assembled biomimetic superhydrophobic hierarchical arrays.

    Science.gov (United States)

    Yang, Hongta; Dou, Xuan; Fang, Yin; Jiang, Peng

    2013-09-01

    Here, we report a simple and inexpensive bottom-up technology for fabricating superhydrophobic coatings with hierarchical micro-/nano-structures, which are inspired by the binary periodic structure found on the superhydrophobic compound eyes of some insects (e.g., mosquitoes and moths). Binary colloidal arrays consisting of exemplary large (4 and 30 μm) and small (300 nm) silica spheres are first assembled by a scalable Langmuir-Blodgett (LB) technology in a layer-by-layer manner. After surface modification with fluorosilanes, the self-assembled hierarchical particle arrays become superhydrophobic with an apparent water contact angle (CA) larger than 150°. The throughput of the resulting superhydrophobic coatings with hierarchical structures can be significantly improved by templating the binary periodic structures of the LB-assembled colloidal arrays into UV-curable fluoropolymers by a soft lithography approach. Superhydrophobic perfluoroether acrylate hierarchical arrays with large CAs and small CA hysteresis can be faithfully replicated onto various substrates. Both experiments and theoretical calculations based on the Cassie's dewetting model demonstrate the importance of the hierarchical structure in achieving the final superhydrophobic surface states. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Superhydrophobic nitric oxide-releasing xerogels.

    Science.gov (United States)

    Storm, Wesley L; Youn, Jonghae; Reighard, Katelyn P; Worley, Brittany V; Lodaya, Hetali M; Shin, Jae Ho; Schoenfisch, Mark H

    2014-08-01

    Superhydrophobic nitric oxide (NO)-releasing xerogels were prepared by spray-coating a fluorinated silane/silica composite onto N-diazeniumdiolate NO donor-modified xerogels. The thickness of the superhydrophobic layer was used to extend NO release durations from 59 to 105h. The resulting xerogels were stable, maintaining superhydrophobicity for up to 1month (the longest duration tested) when immersed in solution, with no leaching of silica or undesirable fragmentation detected. The combination of superhydrophobicity and NO release reduced viable Pseudomonas aeruginosa adhesion by >2-logs. The killing effect of NO was demonstrated at longer bacterial contact times, with superhydrophobic NO-releasing xerogels resulting in 3.8-log reductions in adhered viable bacteria vs. controls. With no observed toxicity to L929 murine fibroblasts, NO-releasing superhydrophobic membranes may be valuable antibacterial coatings for implants as they both reduce adhesion and kill bacteria that do adhere. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  11. Simple synthesis of smart magnetically driven fibrous films for remote controllable oil removal

    Science.gov (United States)

    Wu, Jing; Wang, Nü; Zhao, Yong; Jiang, Lei

    2015-01-01

    Inspired by the marine mussel adhesive protein, smart, magnetically controllable, oil adsorption nanofibrous materials were successfully fabricated in this research. Taking advantage of the properties of dopamine whose molecular structure mimics the single unit of the marine mussel adhesive protein and can be polymerized in alkaline solution forming a ``glue'' layer on many kinds of material surfaces, magnetic iron(ii, iii) oxide (Fe3O4) nanoparticles were easily and robustly anchored on to electrospun poly(vinylidene fluoride) fibrous films. After fluorination, the as-prepared hierarchical structured films exhibited superhydrophobicity, superoleophilicity and an excellent oil adsorption capacity from water. Importantly, because of the magnetically controllable property endowed by the Fe3O4 nanoparticles, such fibrous films act as a ``smart magnetically controlled oil removal carrier'', which effectively overcome the drawbacks of other in situ oil adsorbant materials and can also be easily recovered. This work provides a simple strategy to fabricate magnetic responsive intelligent oil removal materials, which will find broad applications in complex environment oil-water separation.Inspired by the marine mussel adhesive protein, smart, magnetically controllable, oil adsorption nanofibrous materials were successfully fabricated in this research. Taking advantage of the properties of dopamine whose molecular structure mimics the single unit of the marine mussel adhesive protein and can be polymerized in alkaline solution forming a ``glue'' layer on many kinds of material surfaces, magnetic iron(ii, iii) oxide (Fe3O4) nanoparticles were easily and robustly anchored on to electrospun poly(vinylidene fluoride) fibrous films. After fluorination, the as-prepared hierarchical structured films exhibited superhydrophobicity, superoleophilicity and an excellent oil adsorption capacity from water. Importantly, because of the magnetically controllable property endowed by the Fe3

  12. Fabrication of superhydrophobic film by microcellular plastic foaming method

    Science.gov (United States)

    Zhang, Zhen Xiu; Li, Ya Nan; Xia, Lin; Ma, Zhen Guo; Xin, Zhen Xiang; Kim, Jin Kuk

    2014-08-01

    To solve the complicated manufacturing operation and the usage of toxic solvent problems, a simple and novel method to fabricate superhydrophobic film by surface foaming method was introduced in this paper. The superhydrophobic property of the foamed material was obtained at a contact angle >150° and a rolling angle about 8°. The foamed material can instantly generate its superhydrophobicity via peeling process. The effects of blowing agent content, foaming time and peeling rate on the foam structure and superhydrophobicity were studied.

  13. Modification of PLGA Nanofibrous Mats by Electron Beam Irradiation for Soft Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    Jae Baek Lee

    2015-01-01

    Full Text Available Biodegradable poly(lactide-co-glycolide (PLGA has found widespread use in modern medical practice. However, the degradation rate of PLGA should be adjusted for specific biomedical applications such as tissue engineering, drug delivery, and surgical implantation. This study focused on the effect of electron beam radiation on nanofibrous PLGA mats in terms of physical properties and degradation behavior with cell proliferation. PLGA nanofiber mats were prepared by electrospinning, and electron beam was irradiated at doses of 50, 100, 150, 200, 250, and 300 kGy. PLGA mats showed dimensional integrity after electron beam irradiation without change of fiber diameter. The degradation behavior of a control PLGA nanofiber (0 kGy and electron beam-irradiated PLGA nanofibers was analyzed by measuring the molecular weight, weight loss, change of chemical structure, and fibrous morphology. The molecular weight of the PLGA nanofibers decreased with increasing electron beam radiation dose. The mechanical properties of the PLGA nanofibrous mats were decreased with increasing electron beam irradiation dose. Cell proliferation behavior on all electron beam irradiated PLGA mats was similar to the control PLGA mats. Electron beam irradiation of PLGA nanofibrous mats is a potentially useful approach for modulating the biodegradation rate of tissue-specific nonwoven nanofibrous scaffolds, specifically for soft tissue engineering applications.

  14. Directed Growth of Virus Nanofilaments on a Superhydrophobic Surface

    KAUST Repository

    Marinaro, Giovanni

    2015-06-17

    The evaporation of single droplets of colloidal tobacco mosaic virus (TMV) nanoparticles on a superhydrophobic surface with a hexagonal pillar-pattern results in the formation of coffee-ring type residues. We imaged surface features by optical, scanning electron, and atomic force microscopies. Bulk features were probed by raster-scan X-ray nanodiffraction. At ∼100 pg/μL nanoparticle concentration, the rim of the residue connects to neighboring pillars via fibrous extensions containing flow-aligned crystalline domains. At ∼1 pg/μL nanoparticle concentration, nanofilaments of ¥80 nm diameter and ∼20 μm length are formed, extending normal to the residue-rim across a range of pillars. X-ray scattering is dominated by the nanofilament form-factor but some evidence for crystallinity has been obtained. The observation of sheets composed of stacks of self-assembled nanoparticles deposited on pillars suggests that the nanofilaments are drawn from a structured droplet interface. © 2015 American Chemical Society.

  15. Molecular ecology of microbial mats

    NARCIS (Netherlands)

    H. Bolhuis; M.S. Cretoiu; L.J. Stal

    2014-01-01

    Phototrophic microbial mats are ideal model systems for ecological and evolutionary analysis of highly diverse microbial communities. Microbial mats are small-scale, nearly closed, and self-sustaining benthic ecosystems that comprise the major element cycles, trophic levels, and food webs. The steep

  16. Bouncing Water Droplet on a Superhydrophobic Carbon Nanotube Array

    OpenAIRE

    Aria, Adrianus I.; Gharib, Morteza

    2010-01-01

    Over the past few decades, superhydrophobic materials have attaracted a lot of interests, due to their numerous practical applications. Among various superhydrophobic materials, carbon nanotube arrays have gained enormous attentions simply because of their outstanding properties. The impact dynamic of water droplet on a superhydrophobic carbon nanotube array is shown in this fluid dynamics video.

  17. Auspicious tatami mat arrangements

    CERN Document Server

    Erickson, Alejandro; Schurch, Mark; Woodcock, Jennifer

    2011-01-01

    An \\emph{auspicious tatami mat arrangement} is a tiling of a rectilinear region with two types of tiles, $1 \\times 2$ tiles (dimers) and $1 \\times 1$ tiles (monomers). The tiles must cover the region and satisfy the constraint that no four corners of the tiles meet; such tilings are called \\emph{tatami tilings}. The main focus of this paper is when the rectilinear region is a rectangle. We provide a structural characterization of rectangular tatami tilings and use it to prove that the tiling is completely determined by the tiles that are on its border. We prove that the number of tatami tilings of an $n \\times n$ square with $n$ monomers is $n2^{n-1}$. We also show that, for fixed-height, the generating function for the number of tatami tilings of a rectangle is a rational function, and outline an algorithm that produces the generating function.

  18. Vapor stabilizing surfaces for superhydrophobicity

    Science.gov (United States)

    Patankar, Neelesh

    2010-11-01

    The success of rough substrates designed for superhydrophobicity relies crucially on the presence of air pockets in the roughness grooves. This air is supplied by the surrounding environment. However, if the rough substrates are used in enclosed configurations, such as in fluidic networks, the air pockets may not be sustained in the roughness grooves. In this work a design approach based on sustaining a vapor phase of the liquid in the roughness grooves, instead of relying on the presence of air, is explored. The resulting surfaces, referred to as vapor stabilizing substrates, are deemed to be robust against wetting transition even if no air is present. Applications of this approach include low drag surfaces, nucleate boiling, and dropwise condensation heat transfer, among others.

  19. Water impacting on superhydrophobic macrotextures.

    Science.gov (United States)

    Gauthier, Anaïs; Symon, Sean; Clanet, Christophe; Quéré, David

    2015-08-11

    It has been recently shown that the presence of macrotextures on superhydrophobic materials can markedly modify the dynamics of water impacting them, and in particular significantly reduce the contact time of bouncing drops, compared with what is observed on a flat surface. This finding constitutes a significant step in the maximization of water repellency, since it enables to minimize even further the contact between solid and liquid. It also opens a new axis of research on the design of super-structures to induce specific functions such as anti-freezing, liquid fragmentation and/or recomposition, guiding, trapping and so on. Here we show that the contact time of drops bouncing on a repellent macrotexture takes discrete values when varying the impact speed. This allows us to propose a quantitative analysis of the reduction of contact time and thus to understand how and why macrotextures can control the dynamical properties of bouncing drops.

  20. Pancake bouncing on superhydrophobic surfaces

    Science.gov (United States)

    Liu, Yahua; Moevius, Lisa; Xu, Xinpeng; Qian, Tiezheng; Yeomans, Julia M.; Wang, Zuankai

    2014-07-01

    Engineering surfaces that promote rapid drop detachment is of importance to a wide range of applications including anti-icing, dropwise condensation and self-cleaning. Here we show how superhydrophobic surfaces patterned with lattices of submillimetre-scale posts decorated with nanotextures can generate a counter-intuitive bouncing regime: drops spread on impact and then leave the surface in a flattened, pancake shape without retracting. This allows a fourfold reduction in contact time compared with conventional complete rebound . We demonstrate that the pancake bouncing results from the rectification of capillary energy stored in the penetrated liquid into upward motion adequate to lift the drop. Moreover, the timescales for lateral drop spreading over the surface and for vertical motion must be comparable. In particular, by designing surfaces with tapered micro/nanotextures that behave as harmonic springs, the timescales become independent of the impact velocity, allowing the occurrence of pancake bouncing and rapid drop detachment over a wide range of impact velocities.

  1. Superhydrophobicity enhancement through substrate flexibility.

    Science.gov (United States)

    Vasileiou, Thomas; Gerber, Julia; Prautzsch, Jana; Schutzius, Thomas M; Poulikakos, Dimos

    2016-11-22

    Inspired by manifestations in nature, microengineering and nanoengineering of synthetic materials to achieve superhydrophobicity has been the focus of much work. Generally, hydrophobicity is enhanced through the combined effects of surface texturing and chemistry; being durable, rigid materials are the norm. However, many natural and technical surfaces are flexible, and the resulting effect on hydrophobicity has been largely ignored. Here, we show that the rational tuning of flexibility can work synergistically with the surface microtexture or nanotexture to enhance liquid repellency performance, characterized by impalement and breakup resistance, contact time reduction, and restitution coefficient increase. Reduction in substrate areal density and stiffness imparts immediate acceleration and intrinsic responsiveness to impacting droplets (∼350 × g), mitigating the collision and lowering the impalement probability by ∼60% without the need for active actuation. Furthermore, we exemplify the above discoveries with materials ranging from man-made (thin steel or polymer sheets) to nature-made (butterfly wings).

  2. Atomically Bonded Transparent Superhydrophobic Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Aytug, Tolga [ORNL

    2015-08-01

    Maintaining clarity and avoiding the accumulation of water and dirt on optically transparent surfaces such as US military vehicle windshields, viewports, periscope optical head windows, and electronic equipment cover glasses are critical to providing a high level of visibility, improved survivability, and much-needed safety for warfighters in the field. Through a combination of physical vapor deposition techniques and the exploitation of metastable phase separation in low-alkali borosilicate, a novel technology was developed for the fabrication of optically transparent, porous nanostructured silica thin film coatings that are strongly bonded to glass platforms. The nanotextured films, initially structurally superhydrophilic, exhibit superior superhydrophobicity, hence antisoiling ability, following a simple but robust modification in surface chemistry. The surfaces yield water droplet contact angles as high as 172°. Moreover, the nanostructured nature of these coatings provides increased light scattering in the UV regime and reduced reflectivity (i.e., enhanced transmission) over a broad range of the visible spectrum. In addition to these functionalities, the coatings exhibit superior mechanical resistance to abrasion and are thermally stable to temperatures approaching 500°C. The overall process technology relies on industry standard equipment and inherently scalable manufacturing processes and demands only nontoxic, naturally abundant, and inexpensive base materials. Such coatings, applied to the optical components of current and future combat equipment and military vehicles will provide a significant strategic advantage for warfighters. The inherent self-cleaning properties of such superhydrophobic coatings will also mitigate biofouling of optical windows exposed to high-humidity conditions and can help decrease repair/replacement costs, reduce maintenance, and increase readiness by limiting equipment downtime.

  3. Electroactivity of PVDF electrospun fiber mats and ZNO-PVDF composites

    OpenAIRE

    Öğüt, Erdem; Ogut, Erdem

    2007-01-01

    Poly (vinylidene fluoride) (PVDF), an electroactive polymer, has great distinctions for its mechanical properties compared to highly brittle electroceramics. Its piezoelectricity however is not immediately utilizable after being cast in film form, and the cast PVDF film requires additional processes, such as mechanical stretching and poling. In this thesis, alternative to cast PVDF film, electroactive characteristics of PVDF fibrous mats produced by electrospinning are investigated to seek wh...

  4. Influence of Superhydrophobic Properties on Deicing

    Science.gov (United States)

    Nazhipkyzy, M.; Mansurov, Z. A.; Amirfazli, A.; Esbosin, A.; Temirgaliyeva, T. S.; Lesbayev, B. T.; Aliyev, E. T.; Prikhodko, N. G.

    2016-11-01

    Nowadays the creation of anti-icing, or deicing, surfaces is one of the most important problems, as such surfaces are widely used in aeronautics, wind turbines, and telecommunication antennas. In this paper, we focus mainly on reducing the ice adhesion forces and easy ice removal, once ice has formed. Removal of a liquid from a surface can be provided by modification of the surface wettability by means of applying superhydrophobic coatings. Such coatings are water-resistant, i.e., are characterized by low water adhesion forces. To study the impact of superhydrophobic coatings, tests were performed on the surface of a wing in a wind tunnel. By spraying Teflon and polyphenylene sulfide (PPS) on the wing, we obtained a superhydrophobic film. This film has a structure that provides superhydrophobic properties, so that the wetting angle is above 140°. A comparison of the resulting surface with a clean Teflon one shows that adhesion of the Teflon + PPS mixture to an aluminum surface is five times higher. We also investigate the degree of ice formation on the surfaces of simple and superhydrophobic aircraft wings at a temperature of -18°C. It was shown that ice was formed on a simple wing within 40 s and on a superhydrophobic wing within 25 s. When the simple wing with a mass of 23 g was inserted into the wind tunnel, its mass reached 50 g, and for a superhydrophobic wing with a mass of 26 g the latter reached 42 g. The sample of the airfoil wing we prepared has a low adhesion, which helps in easy ice removal.

  5. Degradação in situ da matéria seca e da fração fibrosa do capim marandu obtido por diferentes métodos de amostragem, no período seco do ano Dry matter and fibrous fraction in situ degradability of palissade grass sampled through different methods in the dry season

    Directory of Open Access Journals (Sweden)

    Rean Augusto Zaninetti

    2010-06-01

    Full Text Available Este trabalho foi realizado na Faculdade de Ciências Agrárias Veterinárias - Unesp - Jaboticabal e foi conduzido, com o objetivo de avaliar a influência do método de amostragem do pasto sobre a degradabilidade in situ da matéria seca e da fração fibrosa de capim Marandu, colhido no período seco dos anos de 2003 e 2005. O experimento foi instalado em delineamento de blocos casualizados com parcela subdividida, com três repetições, representadas pelos piquetes amostrados. Nas parcelas, foram avaliados cinco métodos de amostragens de forragem (método do quadrado metálico; método de avaliação através de extrusa de bovino da raça Nelore; método de avaliação por meio de extrusa de bovino Cruzado (Red Angus x Nelore; método de avaliação por meio do pastejo, simulando bovino da raça Nelore; método de avaliação por meio do pastejo, simulando bovino Cruzado (Red Angus x Nelore e as subparcelas foram constituídas pelos anos de amostragem, 2003 e 2005. Foram determinadas as frações da cinética ruminal: solúvel "A"; insolúvel potencialmente degradável "B"; taxa de degradação "Kd"; degradação potencial (DP e fração não degradável "C" da MS e degradação potencial (DP, fração não degradável "C" e taxa de degradação "Kd" da FDN e da FDA. De acordo com os resultados obtidos, observou-se que o método do quadrado metálico subestimou as características da degradação do capim. Os métodos do pastejo simulado se assemelharam muito ao das extrusas, no entanto, a prática do simulador é que assegurou a amostragem eficiente, conforme foi constatado pelos dados obtidos no ano de 2003 e 2005.This experiment was carried out at the Faculdade de Ciências Agrárias Veterinárias - Unesp - Jaboticabal during dry season, to evaluate the effects of sampling methods on the Marandu grass dry matter and cell wall in situ degradability. The data were analyzed according to a randomized block design with three replications

  6. Optic Nerve Decompression for Orbitofrontal Fibrous Dysplasia

    OpenAIRE

    Abe, Takumi; Sato, Kaneshige; Otsuka, Takaharu; Kawamura, Noriyoshi; Shimazu, Motohiko; Izumiyama, Hitoshi; Matsumoto, Kiyoshi

    2002-01-01

    Orbitofrontal fibrous dysplasia often involves the bony orbit and the optic canal. Although fibrous dysplasia reportedly produces compression of the optic nerve leading to visual distrubances, optic nerve decompression in patients without clinical signs of optic neuropathy is still controversial. We describe two patients with orbitofrontal fibrous dysplasia without signs of visual disturbance and one patient with McCune-Albright syndrome and progressive visual impairment. Optic nerve decompre...

  7. Oral benign fibrous histiocytoma: two case reports

    OpenAIRE

    Menditti, Dardo; Laino, Luigi; Mezzogiorno, Antonio; Sava, Sara; Bianchi, Alexander; Caruso, Giovanni; Di Maio, Luigi; Baldi, Alfonso

    2009-01-01

    Fibrous histiocytoma is a benign soft tissue tumour arising as a fibrous mass everywhere in the human body. The involvement of the oral cavity is rare. We report two cases of benign fibrous histiocytoma that localized in the oral cavity. The clinical and histological features of the lesion are reported. Finally, a literature revision of this pathology at the level of the oral cavity is reported.

  8. Drag reduction properties of superhydrophobic mesh pipes

    Science.gov (United States)

    Geraldi, Nicasio R.; Dodd, Linzi E.; Xu, Ben B.; Wells, Gary G.; Wood, David; Newton, Michael I.; McHale, Glen

    2017-09-01

    Even with the recent extensive study into superhydrophobic surfaces, the fabrication of such surfaces on the inside walls of a pipe remains challenging. In this work we report a convenient bi-layered pipe design using a thin superhydrophobic metallic mesh formed into a tube, supported inside another pipe. A flow system was constructed to test the fabricated bi-layer pipeline, which allowed for different constant flow rates of water to be passed through the pipe, whilst the differential pressure was measured, from which the drag coefficient (ƒ) and Reynolds numbers (Re) were calculated. Expected values of ƒ were found for smooth glass pipes for the Reynolds number (Re) range 750-10 000, in both the laminar and part of the turbulent regimes. Flow through plain meshes without the superhydrophobic coating were also measured over a similar range (750  superhydrophobic coating, ƒ was found for 4000  superhydrophobic mesh can support a plastron and provide a drag reduction compared to a plain mesh, however, the plastron is progressively destroyed with use and in particular at higher flow rates.

  9. Testing the performance of superhydrophobic aluminum surfaces.

    Science.gov (United States)

    Ruiz-Cabello, F Javier Montes; Ibáñez-Ibáñez, Pablo F; Gómez-Lopera, J Francisco; Martínez-Aroza, José; Cabrerizo-Vílchez, Miguel; Rodríguez-Valverde, Miguel A

    2017-12-15

    The analysis of wetting properties of superhydrophobic surfaces may be a difficult task due to the restless behavior of drops on this type of surfaces and the limitations of goniometry for high contact angles. A method to validate the performance of superhydrophobic surfaces, rather than standard goniometry, is required. In this work, we used bouncing drop dynamics as a useful tool to predict the water repellency of different superhydrophobic surfaces. From bouncing drop experiments conducted over a wide range of superhydrophobic surfaces, we found that those surfaces with a proper roughness degree and homogeneous chemical composition showed higher water-repellency. We also conducted a drop condensation study at saturating conditions aimed to determine whether there is direct correlation between water repellency and condensation delay. We found that the drop condensation process is strongly related to the surface topography, as well as the intrinsic wettability. The condensation is promoted on rough surfaces but it is delayed on intrinsically hydrophobic surfaces. However, the differences found in condensation delay between the superhydrophobic surfaces explored in this study cannot be justified by their chemical homogeneity nor their efficiency as water repellent surfaces, separately. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Cotton fabrics with single-faced superhydrophobicity.

    Science.gov (United States)

    Liu, Yuyang; Xin, J H; Choi, Chang-Hwan

    2012-12-18

    This article reports on the fabrication of cotton fabrics with single-faced superhydrophobicity using a simple foam finishing process. Unlike most commonly reported superhydrophobic fabrics, the fabrics developed in this study exhibit asymmetric wettability on their two faces: one face showing superhydrophobic behavior (highly nonwetting or water-repellent characteristics) and the other face retaining the inherent hydrophilic nature of cotton. The superhydrophobic face exhibits a low contact angle hysteresis of θ(a)/θ(r) = 151°/144° (θ(a), advancing contact angle; θ(r), receding contact angle), which enables water drops to roll off the surface easily so as to endow the surface with well-known self-cleaning properties. The untreated hydrophilic face preserves its water-absorbing capability, resulting in 44% of the water-absorbing capacity compared to that of the original cotton samples with both sides untreated (hydrophilic). The single-faced superhydrophobic fabrics also retain moisture transmissibility that is as good as that of the original untreated cotton fabrics. They also show robust washing fastness with the chemical cross-linking process of hydrophobic fluoropolymer to fabric fibers. Fabric materials with such asymmetric or gradient wettability will be of great use in many applications such as unidirectional liquid transporting, moisture management, microfluidic systems, desalination of seawater, flow management in fuel cells, and water/oil separation.

  11. Dynamic Defrosting on Scalable Superhydrophobic Surfaces.

    Science.gov (United States)

    Murphy, Kevin R; McClintic, William T; Lester, Kevin C; Collier, C Patrick; Boreyko, Jonathan B

    2017-07-19

    Recent studies have shown that frost can grow in a suspended Cassie state on nanostructured superhydrophobic surfaces. During defrosting, the melting sheet of Cassie frost spontaneously dewets into quasi-spherical slush droplets that are highly mobile. Promoting Cassie frost would therefore seem advantageous from a defrosting standpoint; however, nobody has systematically compared the efficiency of defrosting Cassie ice versus defrosting conventional surfaces. Here, we characterize the defrosting of an aluminum plate, one-half of which exhibits a superhydrophobic nanostructure while the other half is smooth and hydrophobic. For thick frost sheets (>1 mm), the superhydrophobic surface was able to dynamically shed the meltwater, even at very low tilt angles. In contrast, the hydrophobic surface was unable to shed any appreciable meltwater even at a 90° tilt angle. For thin frost layers (≲1 mm), not even the superhydrophobic surface could mobilize the meltwater. We attribute this to the large apparent contact angle of the meltwater, which for small amounts of frost serves to minimize coalescence events and prevent droplets from approaching the capillary length. Finally, we demonstrate a new mode of dynamic defrosting using an upside-down surface orientation, where the melting frost was able to uniformly detach from the superhydrophobic side and subsequently pull the frost from the hydrophobic side in a chain reaction. Treating surfaces to enable Cassie frost is therefore very desirable for enabling rapid and low-energy thermal defrosting, but only for frost sheets that are sufficiently thick.

  12. Mechanical durability of superhydrophobic and oleophobic copper meshes

    Science.gov (United States)

    Yin, Linting; Yang, Jin; Tang, Yongcai; Chen, Lin; Liu, Can; Tang, Hua; Li, Changsheng

    2014-10-01

    We developed a simple and inexpensive method to prepare the superhydrophobic and oleophobic copper meshes with rough structures fabrication and chemical modification. The achieved surfaces displayed liquid-repellent toward water and several organic liquids (such as hexadecane), which possessed much lower surface tension than that of water. Liquid repellency of the fabricated superhydrophobic copper mesh was demonstrated by visible experiment results and contact angle measurements. Even if the superhydrophobic copper mesh was rolled up, it still kept the superhydrophobicity. The mechanical durability was investigated by finger touch and mechanical abrasion tests. The results indicated that the copper mesh can maintain its superhydrophobicity against an abrasion length of 300 cm under a high pressure (77.2 kPa). The superhydrophobicity and oleophobicity, combined with mechanical durability, would promote the superhydrophobic surface to practical application in industry in the future.

  13. Stable and transparent superhydrophobic nanoparticle films.

    Science.gov (United States)

    Ling, Xing Yi; Phang, In Yee; Vancso, G Julius; Huskens, Jurriaan; Reinhoudt, David N

    2009-03-01

    A superhydrophobic surface with a static water contact angle (theta(w)) > 150 degrees was created by a simple "dip-coating" method of 60-nm SiO2 nanoparticles onto an amine-terminated (NH2) self-assembled monolayer (SAM) glass/silicon oxide substrate, followed by chemical vapor deposition of a fluorinated adsorbate. For comparison, a close-packed nanoparticle film, formed by convective assembly, gave theta(w) approximately 120 degrees. The stability of the superhydrophobic coating was enhanced by sintering of the nanoparticles in an O2 environment at high temperature (1100 degress C). A sliding angle of cleaning properties of the surface. The dip-coating method can be applied to glass substrates to prepare surfaces that are superhydrophobic and transparent.

  14. Is superhydrophobicity robust with respect to disorder?

    Science.gov (United States)

    De Coninck, Joël; Dunlop, François; Huillet, Thierry

    2013-09-01

    We consider theoretically the Cassie-Baxter and Wenzel states describing the wetting contact angles for rough substrates. More precisely, we consider different types of periodic geometries such as square protrusions and disks in 2D, grooves and nanoparticles in 3D and derive explicitly the contact angle formulas. We also show how to introduce the concept of surface disorder within the problem and, inspired by biomimetism, study its effect on superhydrophobicity. Our results, quite generally, prove that introducing disorder, at fixed given roughness, will lower the contact angle: a disordered substrate will have a lower contact angle than a corresponding periodic substrate. We also show that there are some choices of disorder for which the loss of superhydrophobicity can be made small, making superhydrophobicity robust.

  15. Superhydrophobic behavior of fluorinated carbon nanofiber arrays

    Science.gov (United States)

    Hsieh, Chien-Te; Fan, Wen-Syuan

    2006-06-01

    Superhydrophobic behavior of fluorinated carbon nanofiber (CNF) arrays, prepared by a template-assisted synthesis, has been investigated. A thermal chemical vapor method, using perfluorohexane as the precursor, was used to coat fluorocarbon on the surface of the CNFs, thus lowering their surface tension. The F-coated CNFs exhibited a good water-repellent behavior, i.e., the highest value of contact angle ˜166°. The superhydrophobicity of water droplets on the arrays can be well predicted by a modified Cassie-Baxter model, incorporating the pore size distributions determined from the density functional theory method. This satisfactory result would shed one light on how the variation of opened sizes would induce the superhydrophobicity of nanostructured surfaces.

  16. MICROBIAL MATS - A JOINT VENTURE

    NARCIS (Netherlands)

    VANGEMERDEN, H

    1993-01-01

    Microbial mats characteristically are dominated by a few functional groups of microbes: cyanobacteria, colorless sulfur bacteria, purple sulfur bacteria, and sulfate-reducing bacteria. Their combined metabolic activities result in steep environmental microgradients, particularly of oxygen and sulfid

  17. Fibrous histiocytoma of the laryngeal glottis

    Institute of Scientific and Technical Information of China (English)

    GE Pingjiang; ZHANG Baoquan; GAO Zhiqiang; Wang Hui; CUI Quancai

    2005-01-01

    A case of a fibrous histiocytoma (FH) of the larynx in a 54-year-old male is reported. Laryngeal fibrous histiocytoma is uncommon. The case recurred several times over 4-year period. Its pathology is described including arguments on potential malignancy and the way of management.

  18. Solitary Fibrous Tumor of the Stomach

    Science.gov (United States)

    Hussain, Qulsoom; Shafique, Khurram; Hurairah, Abu; Grossman, Evan B.

    2017-01-01

    Solitary fibrous tumor is a rare mesenchymal neoplasm that usually originates from the pleura, but has been reported in other extrapleural locations. We report a rare case of a solitary fibrous tumor of the stomach, which was successfully treated with endoscopic mucosal resection. PMID:28286800

  19. Enhanced dechlorination of trichloroethylene using electrospun polymer nanofibrous mats immobilized with iron/palladium bimetallic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Hui [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620 (China); College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Huang, Yunpeng; Shen, Mingwu; Guo, Rui; Cao, Xueyan [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Shi, Xiangyang, E-mail: xshi@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620 (China); College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); CQM - Centro de Quimica da Madeira, Universidade da Madeira, Campus da Penteada, 9000-390 Funchal (Portugal)

    2012-04-15

    Fe/Pd bimetallic nanoparticles (NPs) have held great promise for treating trichloroethylene (TCE)-contaminated groundwater, without the accumulation of chlorinated intermediates. However, the conventionally used colloidal Fe/Pd NPs usually aggregate rapidly, resulting in a reduced reactivity. To reduce the particle aggregation, we employed electrospun polyacrylic acid (PAA)/polyvinyl alcohol (PVA) polymer nanofibers as a nanoreactor to immobilize Fe/Pd bimetallic NPs. In the study, the water-stable PAA/PVA nanofibrous mats were complexed with Fe (III) ions via the binding with the free carboxyl groups of PAA for subsequent formation and immobilization of zero-valent iron (ZVI) NPs. Fe/Pd bimetallic NPs were then formed by the partial reduction of Pd(II) ions with ZVI NPs. The formed electrospun nanofibrous mats containing Fe/Pd bimetallic NPs with a diameter of 2.8 nm were characterized by scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, thermogravimetric analysis, and inductively coupled plasma-atomic emission spectroscopy. The Fe/Pd NP-containing electrospun PAA/PVA nanofibrous mats exhibited higher reactivity than that of the ZVI NP-containing mats or colloidal Fe/Pd NPs in the dechlorination of trichloroethylene (TCE), which was used as a model contaminant. With the high surface area to volume ratio, high porosity, and great reusability of the fibrous mats immobilized with the bimetallic NPs, the composite nanofibrous mats should be amenable for applications in remediation of various environmental contaminants.

  20. Fabrication and Characterization of Electrospun Polycaprolactone Blended with Chitosan-Gelatin Complex Nanofibrous Mats

    Directory of Open Access Journals (Sweden)

    Yongfang Qian

    2014-01-01

    Full Text Available Design and fabrication of nanofibrous scaffolds should mimic the native extracellular matrix. This study is aimed at investigating electrospinning of polycaprolactone (PCL blended with chitosan-gelatin complex. The morphologies were observed from scanning electron microscope. As-spun blended mats had thinner fibers than pure PCL. X-ray diffraction was used to analyze the degree of crystallinity. The intensity at two peaks at 2θ of 21° and 23.5° gradually decreased with the percentage of chitosan-gelatin complex increasing. Moreover, incorporation of the complex could obviously improve the hydrophilicity of as-spun blended mats. Mechanical properties of as-spun nanofibrous mats were also tested. The elongation at break of fibrous mats increased with the PCL content increasing and the ultimate tensile strength varied with different weight ratios. The as-spun mats had higher tensile strength when the weight ratio of PCL to CS-Gel was 75/25 compared to pure PCL. Both as-spun PCL scaffolds and PCL/CS-Gel scaffolds supported the proliferation of porcine iliac endothelial cells, and PCL/CS-Gel had better cell viability than pure PCL. Therefore, electrospun PCL/Chitosan-gelatin nanofibrous mats with weight ratio of 75/25 have better hydrophilicity mechanical properties, and cell proliferation and thus would be a promising candidate for tissue engineering scaffolds.

  1. Enhancing the mechanical properties of electrospun polyester mats by heat treatment

    Directory of Open Access Journals (Sweden)

    M. Kancheva

    2015-01-01

    Full Text Available Microfibrous materials with a targeted design based on poly(L-lactic acid (PLA and poly(ε-caprolactone (PCL were prepared by electrospinning and by combining electrospinning and electrospraying. Several approaches were used: (i electrospinning of a common solution of the two polymers, (ii simultaneous electrospinning of two separate solutions of PLA and PCL, (iii electrospinning of PLA solution in conjunction with electrospraying of PCL solution, and (iv alternating layer-by-layer deposition by electrospinning of separate PLA and PCL solutions. The mats were heated at the melting temperature of PCL (60°", thus achieving melting of PCL fibers/particles and thermal sealing of the fibers. The mats subjected to thermal treatment were characterized by greater mean fiber diameters and reduced values of the water contact angle compared to the pristine mats. Heat treatment of the mats affected their thermal stability and led to an increase in the crystallinity degree of PLA incorporated in the mats, whereas that of PCL was reduced. All mats were characterized by enhanced mechanical properties after thermal treatment as compared to the non-treated fibrous materials.

  2. Hierarchically structured polysulfone/titania fibrous membranes with enhanced air filtration performance.

    Science.gov (United States)

    Wan, Huigao; Wang, Na; Yang, Jianmao; Si, Yinsong; Chen, Kun; Ding, Bin; Sun, Gang; El-Newehy, Mohamed; Al-Deyab, Salem S; Yu, Jianyong

    2014-03-01

    Hierarchically structured, superhydrophobic filter medium exhibiting robust filtration performance to airborne particulate were prepared by a facile deposition of electrospun polysulfone/titania nanoparticles (PSU/TiO2 NPs) on a conventional nonwoven substrate. The air permeability, tensile strength and abrasion resistance of pristine PSU fibrous membranes could be finely controlled by regulating the solvent composition and number ratios of jets. By employing the TiO2 NPs incorporation, the pristine PSU fibers were endowed with promising superhydrophobicity with a water contact angle of up to 152°. The quantitative hierarchical roughness analysis using N2 adsorption method has confirmed the major contribution of TiO2 NPs on enhancing the porous structure and surface fractal features with irregular rough structure. Filtration performance studies have revealed that the filtration efficiency and pressure drop of resultant hybrid membranes could be manipulated by tuning the surface composition as well as the hierarchical structures. Furthermore, the as-prepared PSU/TiO2-5 membrane exhibited improved filtration efficiency (99.997%) and pressure drop (45.3 Pa) compared with pristine PSU membrane, which would make them a promising media for fine particle filtration, and a new insight was also provided into the design and development of high performance filter medium based on hierarchical structured fibers.

  3. Dynamics of Ferrofluidic Drops Impacting Superhydrophobic Surfaces

    CERN Document Server

    Bolleddula, D A; Alliseda, A; Bhosale, P; Berg, J C

    2010-01-01

    This is a fluid dynamics video illustrating the impact of ferrofluidic droplets on surfaces of variable wettability. Surfaces studied include mica, teflon, and superhydrophobic. A magnet is placed beneath each surface, which modifies the behavior of the ferrofluid by applying additional downward force apart from gravity resulting in reduced droplet size and increased droplet velocity. For the superhydrophobic droplet a jetting phenomena is shown which only occurs in a limited range of impact speeds, higher than observed before, followed by amplified oscillation due to magnetic field as the drop stabilizes on the surface.

  4. Preparation of poly(ethylene glycol/polylactide hybrid fibrous scaffolds for bone tissue engineering

    Directory of Open Access Journals (Sweden)

    Ni P

    2011-11-01

    Full Text Available PeiYan Ni, ShaoZhi Fu, Min Fan, Gang Guo, Shuai Shi, JinRong Peng, Feng Luo, ZhiYong QianState Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, People's Republic of ChinaAbstract: Polylactide (PLA electrospun fibers have been reported as a scaffold for bone tissue engineering application, however, the great hydrophobicity limits its broad application. In this study, the hybrid amphiphilic poly(ethylene glycol (PEG/hydrophobic PLA fibrous scaffolds exhibited improved morphology with regular and continuous fibers compared to corresponding blank PLA fiber mats. The prepared PEG/PLA fibrous scaffolds favored mesenchymal stem cell (MSC attachment and proliferation by providing an interconnected porous extracellular environment. Meanwhile, MSCs can penetrate into the fibrous scaffold through the interstitial pores and integrate well with the surrounding fibers, which is very important for favorable application in tissue engineering. More importantly, the electrospun hybrid PEG/PLA fibrous scaffolds can enhance MSCs to differentiate into bone-associated cells by comprehensively evaluating the representative markers of the osteogenic procedure with messenger ribonucleic acid quantitation and protein analysis. MSCs on the PEG/PLA fibrous scaffolds presented better differentiation potential with higher messenger ribonucleic acid expression of the earliest osteogenic marker Cbfa-1 and mid-stage osteogenic marker Col I. The significantly higher alkaline phosphatase activity of the PEG/PLA fibrous scaffolds indicated that these can enhance the differentiation of MSCs into osteoblast-like cells. Furthermore, the higher messenger ribonucleic acid level of the late osteogenic differentiation markers OCN (osteocalcin and OPN (osteopontin, accompanied by the positive Alizarin red S staining, showed better maturation of osteogenic induction on the PEG/PLA fibrous scaffolds at the

  5. Small droplets on superhydrophobic substrates.

    Science.gov (United States)

    Gross, Markus; Varnik, Fathollah; Raabe, Dierk; Steinbach, Ingo

    2010-05-01

    We investigate the wetting behavior of liquid droplets on rough hydrophobic substrates for the case of droplets that are of comparable size to the surface asperities. Using a simple three-dimensional analytical free-energy model, we have shown in a recent letter [M. Gross, F. Varnik, and D. Raabe, EPL 88, 26002 (2009)] that, in addition to the well-known Cassie-Baxter and Wenzel states, there exists a further metastable wetting state where the droplet is immersed into the texture to a finite depth, yet not touching the bottom of the substrate. Due to this new state, a quasistatically evaporating droplet can be saved from going over to the Wenzel state and instead remains close to the top of the surface. In the present paper, we give an in-depth account of the droplet behavior based on the results of extensive computer simulations and an improved theoretical model. In particular, we show that releasing the assumption that the droplet is pinned at the outer edges of the pillars improves the analytical results for larger droplets. Interestingly, all qualitative aspects, such as the existence of an intermediate minimum and the "reentrant transition," remain unchanged. We also give a detailed description of the evaporation process for droplets of varying sizes. Our results point out the role of droplet size for superhydrophobicity and give hints for achieving the desired wetting properties of technically produced materials.

  6. Dual-biomimetic superhydrophobic electrospun polystyrene nanofibrous membranes for membrane distillation.

    Science.gov (United States)

    Li, Xiong; Wang, Ce; Yang, Yin; Wang, Xuefen; Zhu, Meifang; Hsiao, Benjamin S

    2014-02-26

    A new type of dual-biomimetic hierarchically rough polystyrene (PS) superhydrophobic micro/nano-fibrous membrane was fabricated via a one-step electrospinning technique at various polymer concentrations from 15 to 30 wt %. The obtained micro/nano-fibers exhibited a nanopapillose, nanoporous, and microgrooved surface morphology that originated from mimicking the micro/nanoscale hierarchical structures of lotus leaf and silver ragwort leaf, respectively. Superhydrophobicity and high porosity of such resultant electrospun nanofibrous membranes make them attractive candidates for membrane distillation (MD) application with low energy water recovery. In this study, two kinds of optimized PS nanofibrous membranes with different thicknesses were applied for desalination via direct contact MD. The membranes maintained a high and stable permeate water vapor flux (104.8 ± 4.9 kg/m(2)·h, 20 g/L NaCl salt feed for a thinner PS nanofibrous membrane with thickness of 60 μm; 51 ± 4.5 kg/m(2)·h, 35 g/L NaCl salt feed for the thicker sample with thickness of 120 μm; ΔT = 50 °C) for a test period of 10 h without remarkable membrane pores wetting detected. These results were better than those of typical commercial polyvinylidene fluoride (PVDF) MD membranes or related PVDF nanofibrous membranes reported in literature, suggesting excellent competency of PS nanofibrous membranes for MD applications.

  7. Honey-based PET or PET/chitosan fibrous wound dressings: effect of honey on electrospinning process.

    Science.gov (United States)

    Arslan, Aysu; Simşek, Murat; Aldemir, Sevcan Dalkıranoğlu; Kazaroğlu, Nur Merve; Gümüşderelioğlu, Menemşe

    2014-07-01

    In this study, fibrous mats were fabricated via electrospinning from solutions of polyethylene terephthalate (PET), PET/chitosan, and PET/honey at different concentrations. The effect of honey and chitosan on electrospinning process was investigated and compared. Fibers containing chitosan had a beaded or ribbon-like/branched morphology, but this morphology improved in the presence of honey. The diameter of electrospun fibers decreased with an increased ratio of honey in PET solution. In addition, fiber deposition area in the collector increased by increasing the honey content. PET/chitosan and PET/honey fibrous mats reached an equilibrium water content in 15 min and their water uptake capacities, which are important for exudating wounds, were found in the range of 280-430% on dry basis. Cytotoxicity evaluation demonstrated that fibers exhibited no cytotoxic activity. This study discloses that PET fibrous mats especially electrospun in the presence of honey could be proposed as potential wound dressing materials owing to their improved processing abilities besides their suitable structural properties.

  8. Nutritional fibrous osteodystrophy in goats

    Directory of Open Access Journals (Sweden)

    Paulo M Bandarra

    2011-10-01

    Full Text Available Seven out of 25 goats from a southern Brazilian flock developed nutritional fibrous osteodystrophy. Affected animals were younger than 1 year of age and were confined in stalls and fed a concentrate ration containing 1:6 calcium:phosphorus ratio. The remaining flock (35 goats was managed at pasture and showed no disease. Clinical signs were characterized by mandibular and maxillary enlargements, varying degrees of mouth opening and protruding tongue, dyspnea, apart of abnormalities of prehension and mastication. Affected animals had increased seric levels of phosphorus and parathormone, as well as higher alkaline phosphatase activity. Postmortem examination on three succumbed goats revealed bilateral enlargement of the maxilla and mandibula, and loose teeth, apart of multiple incomplete rib fractures in one of them. Severe diffuse proliferation of loose connective tissue surrounded the osteoid trabeculae, many of which were partially or completely non-mineralized. Mineralized osteoid trabeculae showed osteoclasts in the Howship's lacunae.

  9. Posttraumatic Cranial Cystic Fibrous Dysplasia

    Directory of Open Access Journals (Sweden)

    Arata Tomiyama

    2011-01-01

    Full Text Available A 14-year-old was girl admitted to our hospital with a subcutaneous mass of the occipital head. The mass had grown for 6 years, after she had sustained a head injury at the age of 6, and was located directly under a previous wound. Skull X-ray Photograph (xp, computed tomography (CT, and magnetic resonance imaging (MRI showed a bony defect and cystic changes in the skull corresponding to a subcutaneous mass. Bone scintigraphy revealed partial accumulation. The patient underwent total removal of the skull mass, and the diagnosis from the pathological findings of the cyst wall was fibrous dysplasia (FD. The radiographic findings for cystic cranial FD can be various. Progressive skull disease has been reported to be associated with head trauma, but the relationship between cranial FD and head trauma has not been previously reported. Previous studies have suggested that c-fos gene expression is a key mechanism in injury-induced FD.

  10. Preparation of a durable superhydrophobic membrane by electrospinning poly (vinylidene fluoride) (PVDF) mixed with epoxy-siloxane modified SiO2 nanoparticles: a possible route to superhydrophobic surfaces with low water sliding angle and high water contact angle.

    Science.gov (United States)

    Wang, Shuai; Li, Yapeng; Fei, Xiaoliang; Sun, Mingda; Zhang, Chaoqun; Li, Yaoxian; Yang, Qingbiao; Hong, Xia

    2011-07-15

    A durable superhydrophobic surface with low water sliding angle (SA) and high water contact angle (CA) was obtained by electrospinning poly (vinylidene fluoride) (PVDF) which was mixed with epoxy-siloxane modified SiO(2) nanoparticles. To increase the roughness, modified SiO(2) nanoparticles were introduced into PVDF precursor solution. Then in the electrospinning process, nano-sized SiO(2) particles irregularly inlayed (it could also be regard as self-assembly) in the surface of the micro-sized PVDF mini-islands so as to form a dual-scale structure. This structure was responsible for the superhydrophobicity and self-cleaning property. In addition, epoxy-siloxane copolymer was used to modify the surface of SiO(2) nanoparticles so that the SiO(2) nanoparticles could stick to the surface of the micro-sized PVDF mini-islands. Through the underwater immersion test, the SiO(2) nanoparticles cannot be separated from PVDF easily so as to achieve the effect of durability. We chiefly explore the surface wettability and the relationship between the mass ratio of modified SiO(2) nanoparticles/PVDF and the CA, SA of electrospun mat. As the content of modified SiO(2) nanoparticles increased, the value of CA increased, ranging from 145.6° to 161.2°, and the water SA decreased to 2.17°, apparently indicating that the membrane we fabricated has a perfect effect of superhydrophobicity.

  11. Mimicking natural superhydrophobic surfaces and grasping the wetting process: a review on recent progress in preparing superhydrophobic surfaces.

    Science.gov (United States)

    Yan, Y Y; Gao, N; Barthlott, W

    2011-12-12

    A typical superhydrophobic (ultrahydrophobic) surface can repel water droplets from wetting itself, and the contact angle of a water droplet resting on a superhydrophobic surface is greater than 150°, which means extremely low wettability is achievable on superhydrophobic surfaces. Many superhydrophobic surfaces (both manmade and natural) normally exhibit micro- or nanosized roughness as well as hierarchical structure, which somehow can influence the surface's water repellence. As the research into superhydrophobic surfaces goes deeper and wider, it is becoming more important to both academic fields and industrial applications. In this work, the most recent progress in preparing manmade superhydrophobic surfaces through a variety of methodologies, particularly within the past several years, and the fundamental theories of wetting phenomena related to superhydrophobic surfaces are reviewed. We also discuss the perspective of natural superhydrophobic surfaces utilized as mimicking models. The discussion focuses on how the superhydrophobic property is promoted on solid surfaces and emphasizes the effect of surface roughness and structure in particular. This review aims to enable researchers to perceive the inner principles of wetting phenomena and employ suitable methods for creation and modification of superhydrophobic surfaces. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Superhydrophobic nanocomposite surface topography and ice adhesion.

    Science.gov (United States)

    Davis, Alexander; Yeong, Yong Han; Steele, Adam; Bayer, Ilker S; Loth, Eric

    2014-06-25

    A method to reduce the surface roughness of a spray-casted polyurethane/silica/fluoroacrylic superhydrophobic nanocomposite coating was demonstrated. By changing the main slurry carrier fluid, fluoropolymer medium, surface pretreatment, and spray parameters, we achieved arithmetic surface roughness values of 8.7, 2.7, and 1.6 μm on three test surfaces. The three surfaces displayed superhydrophobic performance with modest variations in skewness and kurtosis. The arithmetic roughness level of 1.6 μm is the smoothest superhydrophobic surface yet produced with these spray-based techniques. These three nanocomposite surfaces, along with a polished aluminum surface, were impacted with a supercooled water spray in icing conditions, and after ice accretion occurred, each was subjected to a pressurized tensile test to measure ice-adhesion. All three superhydrophobic surfaces showed lower ice adhesion than that of the polished aluminum surface. Interestingly, the intermediate roughness surface yielded the best performance, which suggests that high kurtosis and shorter autocorrelation lengths improve performance. The most ice-phobic nanocomposite showed a 60% reduction in ice-adhesion strength when compared to polished aluminum.

  13. Stable and Transparent Superhydrophobic Nanoparticle Films

    NARCIS (Netherlands)

    Ling, Xing Yi; Phang, In Yee; Vancso, G. Julius; Huskens, Jurriaan; Reinhoudt, David N.

    2009-01-01

    A superhydrophobic surface with a static water contact angle (θw) > 150° was created by a simple “dip-coating” method of 60-nm SiO2 nanoparticles onto an amine-terminated (NH2) self-assembled monolayer (SAM) glass/silicon oxide substrate, followed by chemical vapor deposition of a fluorinated adsorb

  14. Superhydrophobic surfaces: from fluid mechanics to optics

    NARCIS (Netherlands)

    Rathgen, H.

    2008-01-01

    In this thesis optical diraction was used to study the static and dynamic properties of microscopic liquid-gas interfaces that span between adjacent ridges of a superhydrophobic surface. An observed interference phenomenon at grazing incident angle led to the development of optical gratings with a l

  15. Stable and transparent superhydrophobic nanoparticle films

    NARCIS (Netherlands)

    Ling, X.Y.; Phang, In Yee; Vancso, Gyula J.; Huskens, Jurriaan; Reinhoudt, David

    2009-01-01

    A superhydrophobic surface with a static water contact angle (θw) > 150° was created by a simple “dip-coating” method of 60-nm SiO2 nanoparticles onto an amine-terminated (NH2) self-assembled monolayer (SAM) glass/silicon oxide substrate, followed by chemical vapor deposition of a fluorinated adsorb

  16. Superhydrophobic surfaces: from fluid mechanics to optics

    NARCIS (Netherlands)

    Rathgen, H.

    2008-01-01

    In this thesis optical diraction was used to study the static and dynamic properties of microscopic liquid-gas interfaces that span between adjacent ridges of a superhydrophobic surface. An observed interference phenomenon at grazing incident angle led to the development of optical gratings with a

  17. Molecular ecology of microbial mats.

    Science.gov (United States)

    Bolhuis, Henk; Cretoiu, Mariana Silvia; Stal, Lucas J

    2014-11-01

    Phototrophic microbial mats are ideal model systems for ecological and evolutionary analysis of highly diverse microbial communities. Microbial mats are small-scale, nearly closed, and self-sustaining benthic ecosystems that comprise the major element cycles, trophic levels, and food webs. The steep and fluctuating physicochemical microgradients, that are the result of the ever changing environmental conditions and of the microorganisms' own activities, give rise to a plethora of potential niches resulting in the formation of one of the most diverse microbial ecosystems known to date. For several decades, microbial mats have been studied extensively and more recently molecular biological techniques have been introduced that allowed assessing and investigating the diversity and functioning of these systems. These investigations also involved metagenomics analyses using high-throughput DNA and RNA sequencing. Here, we summarize some of the latest developments in metagenomic analysis of three representative phototrophic microbial mat types (coastal, hot spring, and hypersaline). We also present a comparison of the available metagenomic data sets from mats emphasizing the major differences between them as well as elucidating the overlap in overall community composition.

  18. Fibrous-Ceramic/Aerogel Composite Insulating Tiles

    Science.gov (United States)

    White, Susan M.; Rasky, Daniel J.

    2004-01-01

    Fibrous-ceramic/aerogel composite tiles have been invented to afford combinations of thermal-insulation and mechanical properties superior to those attainable by making tiles of fibrous ceramics alone or aerogels alone. These lightweight tiles can be tailored to a variety of applications that range from insulating cryogenic tanks to protecting spacecraft against re-entry heating. The advantages and disadvantages of fibrous ceramics and aerogels can be summarized as follows: Tiles made of ceramic fibers are known for mechanical strength, toughness, and machinability. Fibrous ceramic tiles are highly effective as thermal insulators in a vacuum. However, undesirably, the porosity of these materials makes them permeable by gases, so that in the presence of air or other gases, convection and gas-phase conduction contribute to the effective thermal conductivity of the tiles. Other disadvantages of the porosity and permeability of fibrous ceramic tiles arise because gases (e.g., water vapor or cryogenic gases) can condense in pores. This condensation contributes to weight, and in the case of cryogenic systems, the heat of condensation undesirably adds to the heat flowing to the objects that one seeks to keep cold. Moreover, there is a risk of explosion associated with vaporization of previously condensed gas upon reheating. Aerogels offer low permeability, low density, and low thermal conductivity, but are mechanically fragile. The basic idea of the present invention is to exploit the best features of fibrous ceramic tiles and aerogels. In a composite tile according to the invention, the fibrous ceramic serves as a matrix that mechanically supports the aerogel, while the aerogel serves as a low-conductivity, low-permeability filling that closes what would otherwise be the open pores of the fibrous ceramic. Because the aerogel eliminates or at least suppresses permeation by gas, gas-phase conduction, and convection, the thermal conductivity of such a composite even at

  19. Radiation-induced intracranial malignant fibrous histiocytoma

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Vitale, J.C.; Slavin, R.E.; McQueen, J.D.

    1976-06-01

    An autopsy case of radiation-induced intracranial malignant fibrous histiocytoma (fibroxanthosarcoma) is reported. The tumor developed in the region of the sella turcica 11 years after high dose radiotherapy of a chromophobe adenoma of the pituitary. The tumor had infiltrated the base of the brain as well as the base of the skull. Metastases were not found. The tumor was composed of an admixture of bizarre fibroblasts, histiocytes and giant cells, xanthoma cells and siderophages, with a storiform fibrous stroma. This appears to be the first documented instance of a malignant fibrous histiocytoma occurring intracranially after local x irradiation.

  20. The "pirate sign" in fibrous dysplasia.

    Science.gov (United States)

    Singnurkar, Amit; Rush, Chris

    2006-11-01

    Fibrous dysplasia commonly involves the skull in both its monostotic and polyostotic variants. We present two cases of fibrous dysplasia involving the sphenoid wing, which were strikingly similar in their bone scan appearance. Both patients demonstrated intense increased uptake of Tc-99m MDP in a pattern reminding us of a "pirate wearing an eyepatch." We propose that this characteristic appearance of fibrous dysplasia of the sphenoid wing be called the "pirate sign." A review of the literature revealed several other pathologic conditions that have been reported to involve the sphenoid bone and should be considered in the differential diagnosis of abnormal bone tracer uptake in this region.

  1. Superhydrophobic Ceramic Coatings by Solution Precursor Plasma Spray

    Science.gov (United States)

    Cai, Yuxuan

    Superhydrophobic surfaces exhibit superior water repellent properties, and they have remarkable potential to improve current energy infrastructure. Substantial research has been performed on the production of superhydrophobic coatings. However, superhydrophobic coatings have not yet been adopted in many industries where potential applications exist due to the limited durability of the coating materials and the complex and costly fabrication processes. Here presented a novel coating technique to manufacture ceramic superhydrophobic coatings rapidly and economically. A rare earth oxide (REO) was selected as the coating material due to its hydrophobic nature and strong mechanical properties, and deposited on stainless steel substrates by solution precursor plasma spray (SPPS). The as-sprayed coating demonstrated a hierarchically structured coating topography, which closely resembles superhydrophobic surfaces in nature. Compared to smooth REO surfaces, the SPPS superhydrophobic coating improved the water contact angle by as much as 65° after vacuum treatment at 1 Pa for 48 hours.

  2. Superhydrophobic surfaces: from natural to biomimetic to functional.

    Science.gov (United States)

    Guo, Zhiguang; Liu, Weimin; Su, Bao-Lian

    2011-01-15

    Nature is the creation of aesthetic functional systems, in which many natural materials have vagarious structures. Inspired from nature, such as lotus leaf, butterfly' wings, showing excellent superhydrophobicity, scientists have recently fabricated a lot of biomimetic superhydrophobic surfaces by virtue of various smart and easy routes. Whilst, many examples, such as lotus effect, clearly tell us that biomimicry is dissimilar to a simple copying or duplicating of biological structures. In this feature article, we review the recent studies in both natural superhydrophobic surfaces and biomimetic superhydrophobic surfaces, and highlight some of the recent advances in the last four years, including the various smart routes to construct rough surfaces, and a lot of chemical modifications which lead to superhydrophobicity. We also review their functions and applications to date. Finally, the promising routes from biomimetic superhydrophobic surfaces in the next are proposed.

  3. Super-hydrophobic bandages and method of making the same

    Science.gov (United States)

    Simpson, John T [Clinton, TN; D'Urso, Brian R [Pittsburgh, PA

    2012-06-05

    A bandage that includes a material, which can be breathable, having a first surface, and a plurality of superhydrophobic particles attached to the first surface. The plurality of superhydrophobic particles ranging in size from about 100 nanometers to about 10 micrometers. The superhydrophobic particles including a protrusive material defining a plurality of nanopores and a plurality of spaced apart nanostructures that define an external boundary of the hydrophobic particles. The nanopores providing a flow through porosity. The first surface can be rendered superhydrophobic by the attached superhydrophobic particles. The material can have a second surface opposite the first surface that is hydrophilic. The superhydrophobic particles can be adhered to the first surface by a binder. Also included is a method of making the bandages described herein.

  4. Atypical Cutaneous Fibrous Histiocytoma: An Unusual and Misleading Variant of Fibrous Histiocytoma

    OpenAIRE

    Soumaya Ben Abdelkrim; Colondane Belajouza; Wafa Jomaa; Nadia Beizig; Zeineb Ben Said; Moncef Mokni; Rafia Nouira; Badreddine Sriha

    2011-01-01

    Atypical fibrous histiocytoma is a distinctive variant of cutaneous fibrous histiocytoma, which is often mistaken histologically for sarcoma and which have a tendency to recur locally and a capacity to metastasize, although very rarely. We report a new case of atypical cutaneous fibrous histiocytoma in a 31-year-old man who presented with a recurrent polypoid nodule on the abdominal wall. The diagnosis was made on the basis of morphological and immunohistochemical findings. We discuss through...

  5. Mechanically robust superhydrophobicity on hierarchically structured Si surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Xiu Yonghao; Hess, Dennis W [School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0100 (United States); Liu Yan; Wong, C P, E-mail: dennis.hess@chbe.gatech.edu, E-mail: cp.wong@mse.gatech.edu [School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, GA 30332-0245 (United States)

    2010-04-16

    Improvement of the robustness of superhydrophobic surfaces is critical in order to achieve commercial applications of these surfaces in such diverse areas as self-cleaning, water repellency and corrosion resistance. In this study, the mechanical robustness of superhydrophobic surfaces was evaluated on hierarchically structured silicon surfaces. The effect of two-scale hierarchical structures on robustness was investigated using an abrasion test and the results compared to those of superhydrophobic surfaces fabricated from polymeric materials and from silicon that contains only nanostructures. Unlike the polymeric and nanostructure-only surfaces, the hierarchical structures retained superhydrophobic behavior after mechanical abrasion.

  6. Solitary Fibrous Tumor of the Uterus

    Directory of Open Access Journals (Sweden)

    Po-Wei Chu

    2006-12-01

    Conclusion: The behavior of solitary fibrous tumors arising from the uterus is difficult to evaluate; therefore, complete surgical excision featuring clear margins and comprehensive follow-up is recommended.

  7. [Solitary fibrous tumours of the kidney].

    Science.gov (United States)

    Gres, Pascal; Avances, Christophe; Ben Naoum, Kamel; Chapuis, Héliette; Costa, Pierre

    2004-02-01

    Solitary fibrous tumours (SFT) are mesenchymal tumours that usually arise from the pleura. Renal SFT are exceptional (9 cases reported in the literature). The authors report a new case discovered during assessment of HT and treated by radical right nephrectomy. The histological appearance is characteristic: a tumour with a fibrous centre, composed of a monomorphic proliferation of spindle cells, with positive CD 34, CD 99, and bcl 2 labelling. The prognosis after complete resection is generally favourable.

  8. Fibrous dysplasia of bone causing unilateral proptosis

    Directory of Open Access Journals (Sweden)

    Reshma Ramakrishnan

    2015-01-01

    Full Text Available Fibrous dysplasia (FD is a slow growing benign noninherited disorder in which normal bones are replaced by fibrous tissue and immature woven bones. Here we report a case of 30-year-old female who presented with unilateral proptosis and lagophthalmos without any visual loss; was diagnosed with polyostotic FD. Patient was taken up for surgery. Osseous reconturing was done by shaving of involved facial bones. Postoperatively, there was a decrease in proptosis and lagophthalmos.

  9. Fibrous dysplasia of bone: a clinicopathologic review

    Directory of Open Access Journals (Sweden)

    Mohan H

    2011-11-01

    Full Text Available Harsh Mohan1, Preeti Mittal1, Irneet Mundi1, Sudhir Kumar21Department of Pathology, 2Department of Orthopedics, Government Medical College, Sector 32, Chandigarh, IndiaAbstract: Fibrous dysplasia of the bones is an uncommon congenital skeletal disorder that is found equally in both genders and is not inherited. Its etiology has been linked to an activating mutation of Gsα and the downstream effects of the resultant increase in cAMP. Fibrous dysplasia is categorized as either monostotic or polyostotic, and may occur as a component of McCune-Albright syndrome or the rare Mazabraud syndrome. Long bones, skull bones, and ribs are the most commonly affected bones. The radiological picture is somewhat variable, including a ground-glass appearance, expansion of the bone, and sclerosis surrounding the lesion. Histologically, fibrous dysplasia shows irregularly-shaped trabeculae of immature, woven bone in a background of variably cellular, loosely arranged fibrous stroma. It may be complicated by pathologic fracture, and rarely by malignant transformation. This review examines interesting issues surrounding the etiology of fibrous dysplasia, its clinical and laboratory manifestations, radiological picture, utility of bone biopsy, gross and microscopic pathology, complications, and its differential diagnostic considerations.Keywords: fibrous dysplasia, McCune-Albright syndrome, monostotic form, polyostotic form

  10. Sparse Coding for Alpha Matting.

    Science.gov (United States)

    Johnson, Jubin; Varnousfaderani, Ehsan; Cholakkal, Hisham; Rajan, Deepu

    2016-04-21

    Existing color sampling based alpha matting methods use the compositing equation to estimate alpha at a pixel from pairs of foreground (F) and background (B) samples. The quality of the matte depends on the selected (F,B) pairs. In this paper, the matting problem is reinterpreted as a sparse coding of pixel features, wherein the sum of the codes gives the estimate of the alpha matte from a set of unpaired F and B samples. A non-parametric probabilistic segmentation provides a certainty measure on the pixel belonging to foreground or background, based on which a dictionary is formed for use in sparse coding. By removing the restriction to conform to (F,B) pairs, this method allows for better alpha estimation from multiple F and B samples. The same framework is extended to videos, where the requirement of temporal coherence is handled effectively. Here, the dictionary is formed by samples from multiple frames. A multi-frame graph model, as opposed to a single image as for image matting, is proposed that can be solved efficiently in closed form. Quantitative and qualitative evaluations on a benchmark dataset are provided to show that the proposed method outperforms current state-of-the-art in image and video matting.

  11. Large-area fabrication of superhydrophobic surfaces for practical applications: an overview

    Science.gov (United States)

    Xue, Chao-Hua; Jia, Shun-Tian; Zhang, Jing; Ma, Jian-Zhong

    2010-01-01

    This review summarizes the key topics in the field of large-area fabrication of superhydrophobic surfaces, concentrating on substrates that have been used in commercial applications. Practical approaches to superhydrophobic surface construction and hydrophobization are discussed. Applications of superhydrophobic surfaces are described and future trends in superhydrophobic surfaces are predicted. PMID:27877336

  12. Large-area fabrication of superhydrophobic surfaces for practical applications: an overview

    Directory of Open Access Journals (Sweden)

    Chao-Hua Xue, Shun-Tian Jia, Jing Zhang and Jian-Zhong Ma

    2010-01-01

    Full Text Available This review summarizes the key topics in the field of large-area fabrication of superhydrophobic surfaces, concentrating on substrates that have been used in commercial applications. Practical approaches to superhydrophobic surface construction and hydrophobization are discussed. Applications of superhydrophobic surfaces are described and future trends in superhydrophobic surfaces are predicted.

  13. Large-area fabrication of superhydrophobic surfaces for practical applications: an overview

    OpenAIRE

    Xue, Chao-Hua; Jia, Shun-Tian; Zhang, Jing; Ma, Jian-Zhong

    2010-01-01

    This review summarizes the key topics in the field of large-area fabrication of superhydrophobic surfaces, concentrating on substrates that have been used in commercial applications. Practical approaches to superhydrophobic surface construction and hydrophobization are discussed. Applications of superhydrophobic surfaces are described and future trends in superhydrophobic surfaces are predicted.

  14. Transverse flow in thin superhydrophobic channels

    CERN Document Server

    Feuillebois, Francois; Vinogradova, Olga I

    2010-01-01

    We provide some general theoretical results to guide the optimization of transverse hydrodynamic phenomena in superhydrophobic channels. Our focus is on the canonical micro- and nanofluidic geometry of a parallel-plate channel with an arbitrary two-component (low-slip and high-slip) coarse texture, varying on scales larger than the channel thickness. By analyzing rigorous bounds on the permeability, over all possible patterns, we optimize the area fractions, slip lengths, geometry and orientation of the surface texture to maximize transverse flow. In the case of two aligned striped surfaces, very strong transverse flows are possible. Optimized superhydrophobic surfaces may find applications in passive microfluidic mixing and amplification of transverse electrokinetic phenomena.

  15. Leidenfrost Vapor Layer Stabilization on Superhydrophobic Surfaces

    Science.gov (United States)

    Vakarelski, Ivan; Patankar, Neelesh; Marston, Jeremy; Chan, Derek; Thoroddsen, Sigurdur

    2012-11-01

    We have performed experiments to investigate the influence of the wettability of a superheated metallic sphere on the stability of a thin vapor layer during the cooling of a sphere immersed in water. For high enough sphere temperatures, a continuous vapor layer (Leidenfrost regime) is observed on the surface of non-superhydrophobic spheres, but below a critical sphere temperature the layer becomes unstable and explosively switches to nuclear boiling regime. In contrast, when the sphere surface is textured and superhydrophobic, the vapor layer is stable and gradually relaxes to the sphere surface until the complete cooling of the sphere, thus avoiding the nuclear boiling transition altogether. This finding could help in the development of heat exchange devices and of vapor layer based drag reducing technologies.

  16. Superhydrophobic resistance to dynamic freshwater biofouling inception.

    Science.gov (United States)

    Krishnan, K Ghokulla; Malm, Peter; Loth, Eric

    2015-01-01

    Superhydrophobic nanotextured surfaces have gained increased usage in various applications due to their non-wetting and self-cleaning abilities. The aim of this study was to investigate nanotextured surfaces with respect to their resistance to the inception of freshwater biofouling at transitional flow conditions. Several coatings were tested including industry standard polyurethane (PUR), polytetrafluoroethylene (PTFE), capstone mixed polyurethane (PUR + CAP) and nanocomposite infused polyurethane (PUR + NC). Each surface was exposed to freshwater conditions in a lake at 4 m s(-1) for a duration of 45 min. The polyurethane exhibited the greatest fouling elements, in terms of both height and number of elements, with the superhydrophobic nanocomposite based polyurethane (PUR + NC) showing very little to no fouling. A correlation between the surface characteristics and the degree of fouling inception was observed.

  17. Superhydrophobic aerogel that does not require per-fluoro compounds or contain any fluorine

    Energy Technology Data Exchange (ETDEWEB)

    Kissel, David J.; Brinker, Charles Jeffrey

    2015-05-26

    Provided are superhydrophobic coatings, devices and articles including superhydrophobic coatings, and methods for preparing the superhydrophobic coatings. The exemplary superhydrophobic device can include a substrate component and one or more superhydrophobic coatings disposed over the substrate component, wherein at least one of the one or more superhydrophobic coatings has a water contact angle of at least about 150.degree. and a contact angle hysteresis of less than about 1.degree.. The one or more superhydrophobic coatings can include an ultra high water content acid catalyzed polysilicate gel, the polysilicate gel including a three dimensional network of silica particles having surface functional groups derivatized with a silylating agent and a plurality of pores.

  18. Fabrication of highly aligned fibrous scaffolds for tissue regeneration by centrifugal spinning technology

    Energy Technology Data Exchange (ETDEWEB)

    Loordhuswamy, Amalorpava Mary [Department of Textile Technology, Anna University, Chennai 600025 (India); Krishnaswamy, Venkat Raghavan; Korrapati, Purna Sai [Department of Biomaterials, CSIR-Central Leather Research Institute, Chennai 600020 (India); Thinakaran, Senthilram [Department of Textile Technology, Anna University, Chennai 600025 (India); Rengaswami, Giri Dev Venkateshwarapuram, E-mail: vrgiridev@yahoo.com [Department of Textile Technology, Anna University, Chennai 600025 (India)

    2014-09-01

    Centrifugal spinning (C-Spin) is an emerging technology which uses centrifugal force to produce ultrafine fibers. Being a voltage free technique it can overcome the limitations of electrospinning. Owing to the unique characteristic features such as high surface area to volume ratio, porosity, mechanical strength and fiber alignment, centrifugal spun (C-spun) fibrous mat has a wide range of scope in various biomedical applications. Higher degree of fiber alignment can be effortlessly achieved by the C-Spin process. In order to prove the versatility of C-Spin system with respect to fiber alignment, Polycaprolactone (PCL) and gelatin were spun taking them as model polymers. The morphological analysis revealed that highly aligned ultrafine fibers with smooth surface are achieved by C-Spinning. Hydrophilicity, porosity and mechanical property results confirm that the C-spun mat is more suitable for tissue engineering applications. In vitro and in vivo experiments proved that the scaffolds are biocompatible and can be efficiently used as a wound dressing material. - Highlights: • Highly aligned PCL/gelatin fibrous scaffolds were prepared by C-Spinning system. • Degree of fiber alignment was influenced by the proportion of gelatin in the blends. • Direction of cell growth was parallel to the direction of fiber alignment. • C-Spun matrices can efficiently accelerate faster wound healing.

  19. A high-efficiency superhydrophobic plasma separator.

    Science.gov (United States)

    Liu, Changchun; Liao, Shih-Chuan; Song, Jinzhao; Mauk, Michael G; Li, Xuanwen; Wu, Gaoxiang; Ge, Dengteng; Greenberg, Robert M; Yang, Shu; Bau, Haim H

    2016-02-01

    To meet stringent limit-of-detection specifications for low abundance target molecules, a relatively large volume of plasma is needed for many blood-based clinical diagnostics. Conventional centrifugation methods for plasma separation are not suitable for on-site testing or bedside diagnostics. Here, we report a simple, yet high-efficiency, clamshell-style, superhydrophobic plasma separator that is capable of separating a relatively large volume of plasma from several hundred microliters of whole blood (finger-prick blood volume). The plasma separator consists of a superhydrophobic top cover with a separation membrane and a superhydrophobic bottom substrate. Unlike previously reported membrane-based plasma separators, the separation membrane in our device is positioned at the top of the sandwiched whole blood film to increase the membrane separation capacity and plasma yield. In addition, the device's superhydrophobic characteristics (i) facilitates the formation of well-defined, contracted, thin blood film with a high contact angle; (ii) minimizes biomolecular adhesion to surfaces; (iii) increases blood clotting time; and (iv) reduces blood cell hemolysis. The device demonstrated a "blood in-plasma out" capability, consistently extracting 65 ± 21.5 μL of plasma from 200 μL of whole blood in less than 10 min without electrical power. The device was used to separate plasma from Schistosoma mansoni genomic DNA-spiked whole blood with a recovery efficiency of >84.5 ± 25.8%. The S. mansoni genomic DNA in the separated plasma was successfully tested on our custom-made microfluidic chip by using loop mediated isothermal amplification (LAMP) method.

  20. Preparation of superhydrophobic surfaces on cotton textiles

    Directory of Open Access Journals (Sweden)

    Chao-Hua Xue et al

    2008-01-01

    Full Text Available Superhydrophobic surfaces were fabricated by the complex coating of silica nanoparticles with functional groups onto cotton textiles to generate a dual-size surface roughness, followed by hydrophobization with stearic acid, 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane or their combination. The wettability and morphology of the as-fabricated surfaces were investigated by contact angle measurement and scanning electron microscopy. Characterizations by transmission electron microscopy, Fourier transformation infrared spectroscopy, and thermal gravimetric analysis were also conducted.

  1. Superhydrophobicity of Hierarchical and ZNO Nanowire Coatings

    Science.gov (United States)

    2014-01-01

    KOH (3 wt%), distilled water and isopropyl alcohol (10% vol%) at 95 C for 50 min. Subsequently, a 10 nm ZnO seed layer wasThis journal is © The Royal...ZnO have been widely used in sensors, piezo-nanogenerators, and solar cells. The hierarchical structures of ZnO nanowires grown on Si pyramid surfaces...exhibiting superhydrophobicity in this work will have promising applications in the next generation photovoltaic devices and solar cells

  2. Modeling and Optimization of Superhydrophobic Condensation

    OpenAIRE

    Miljkovic, Nenad; Enright, Ryan; Wang, Evelyn N.

    2012-01-01

    Superhydrophobic micro/nanostructured surfaces for dropwise condensation have recently received significant attention due to their potential to enhance heat transfer performance by shedding water droplets via coalescence-induced droplet jumping at length scales below the capillary length. However, achieving optimal surface designs for such behavior requires capturing the details of transport processes that is currently lacking. While comprehensive models have been developed for flat hydrophob...

  3. Electrochemical fabrication of superhydrophobic Zn surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jing [Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024 (China); Zhang, Fangdong [Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024 (China); Shanxi Institute of Mechanical and Electrical Engineering, Changzhi 046000 (China); Song, Jinlong, E-mail: songjinlong@mail.dlut.edu.cn [Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024 (China); Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607 (United States); Wang, Long; Qu, Qingsong [Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024 (China); Lu, Yao; Parkin, Ivan [Materials Chemistry Research Centre, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H OAJ (United Kingdom)

    2014-10-01

    Highlights: • A simple electrochemical processing in the mixed electrolyte composed of NaCl and NaNO{sub 3} was developed to fabricate superhydrophobic Zn surfaces. • A layer of micro-nano hierarchical structures was obtained on the processed Zn surfaces. • Reaction mechanism of Zn in mixed electrolyte was analyzed. - Abstract: A superhydrophobic surface with a water contact angle of 165.3° and a tilting angle of 2° was fabricated on a zinc substrate by electrochemical processing using a mixed electrolyte composed of NaCl and NaNO{sub 3}, followed by overcoating with a fluorinated polymer. The fabrication process is based on the electrochemical processing of Zn under an applied electric field. Scanning electron microscope (SEM) and X-ray diffractometer system (XRD) were used to characterize surface morphology and crystal structures. Micrometer-scale pits, protrusions and numerous nanometer-scale dendrite structures were found on the surface. XRD results indicated that the new products formed on the treated surface. The anodic dissolution mechanism of Zn in the electrolyte was analyzed. The effects of processing time, processing current, electrolyte type and electrolyte concentration on surface micromorphology and superhydrophobicity of the samples were also investigated. The results show that the electrochemical processing does not require exacting processing parameters. This method is highly efficient and environmental friendly. The ideal processing conditions to create the optimum superhydrophobic surface are a processing time of 20 min, a current density of 0.2 A/cm{sup 2}, and a mixed electrolyte of 0.1 mol/L NaNO{sub 3} and 0.05 mol/L NaCl.

  4. Highly stable superhydrophobic surfaces under flow conditions

    Science.gov (United States)

    Lee, Moonchan; Yim, Changyong; Jeon, Sangmin

    2015-01-01

    We synthesized hydrophobic anodic aluminum oxide nanostructures with pore diameters of 35, 50, 65, and 80 nm directly on quartz crystal microresonators, and the stability of the resulting superhydrophobicity was investigated under flow conditions by measuring changes in the resonance frequency and dissipation factor. When the quartz substrates were immersed in water, their hydrophobic surfaces did not wet due to the presence of an air interlayer. The air interlayer was gradually replaced by water over time, which caused decreases in the resonance frequency (i.e., increases in mass) and increases in the dissipation factor (i.e., increases in viscous damping). Although the water contact angles of the nanostructures increased with increasing pore size, the stability of their superhydrophobicity increased with decreasing pore size under both static conditions (without flow) and dynamic conditions (with flow); this increase can be attributed to an increase in the solid surface area that interacts with the air layer above the nanopores as the pore size decreases. Further, the effects of increasing the flow rate on the stability of the superhydrophobicity were quantitatively determined.

  5. Dynamic air layer on textured superhydrophobic surfaces

    KAUST Repository

    Vakarelski, Ivan Uriev

    2013-09-03

    We provide an experimental demonstration that a novel macroscopic, dynamic continuous air layer or plastron can be sustained indefinitely on textured superhydrophobic surfaces in air-supersaturated water by a natural gas influx mechanism. This type of plastron is an intermediate state between Leidenfrost vapor layers on superheated surfaces and the equilibrium Cassie-Baxter wetting state on textured superhydrophobic surfaces. We show that such a plastron can be sustained on the surface of a centimeter-sized superhydrophobic sphere immersed in heated water and variations of its dynamic behavior with air saturation of the water can be regulated by rapid changes of the water temperature. The simple experimental setup allows for quantification of the air flux into the plastron and identification of the air transport model of the plastron growth. Both the observed growth dynamics of such plastrons and millimeter-sized air bubbles seeded on the hydrophilic surface under identical air-supersaturated solution conditions are consistent with the predictions of a well-mixed gas transport model. © 2013 American Chemical Society.

  6. Superhydrophobic silica nanoparticles as ultrasound contrast agents.

    Science.gov (United States)

    Jin, Qiaofeng; Lin, Chih-Yu; Kang, Shih-Tsung; Chang, Yuan-Chih; Zheng, Hairong; Yang, Chia-Min; Yeh, Chih-Kuang

    2017-05-01

    Microbubbles have been widely studied as ultrasound contrast agents for diagnosis and as drug/gene carriers for therapy. However, their size and stability (lifetime of 5-12min) limited their applications. The development of stable nanoscale ultrasound contrast agents would therefore benefit both. Generating bubbles persistently in situ would be one of the promising solutions to the problem of short lifetime. We hypothesized that bubbles could be generated in situ by providing stable air nuclei since it has been found that the interfacial nanobubbles on a hydrophobic surface have a much longer lifetime (orders of days). Mesoporous silica nanoparticles (MSNs) with large surface areas and different levels of hydrophobicity were prepared to test our hypothesis. It is clear that the superhydrophobic and porous nanoparticles exhibited a significant and strong contrast intensity compared with other nanoparticles. The bubbles generated from superhydrophobic nanoparticles sustained for at least 30min at a MI of 1.0, while lipid microbubble lasted for about 5min at the same settings. In summary MSNs have been transformed into reliable bubble precursors by making simple superhydrophobic modification, and made into a promising contrast agent with the potentials to serve as theranostic agents that are sensitive to ultrasound stimulation. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Water droplet evaporation from sticky superhydrophobic surfaces

    Science.gov (United States)

    Lee, Moonchan; Kim, Wuseok; Lee, Sanghee; Baek, Seunghyeon; Yong, Kijung; Jeon, Sangmin

    2017-07-01

    The evaporation dynamics of water from sticky superhydrophobic surfaces was investigated using a quartz crystal microresonator and an optical microscope. Anodic aluminum oxide (AAO) layers with different pore sizes were directly fabricated onto quartz crystal substrates and hydrophobized via chemical modification. The resulting AAO layers exhibited hydrophobic or superhydrophobic characteristics with strong adhesion to water due to the presence of sealed air pockets inside the nanopores. After placing a water droplet on the AAO membranes, variations in the resonance frequency and Q-factor were measured throughout the evaporation process, which were related to changes in mass and viscous damping, respectively. It was found that droplet evaporation from a sticky superhydrophobic surface followed a constant contact radius (CCR) mode in the early stage of evaporation and a combination of CCR and constant contact angle modes without a Cassie-Wenzel transition in the final stage. Furthermore, AAO membranes with larger pore sizes exhibited longer evaporation times, which were attributed to evaporative cooling at the droplet interface.

  8. Fabricating Superhydrophobic Polymeric Materials for Biomedical Applications

    Science.gov (United States)

    Kaplan, Jonah; Grinstaff, Mark

    2015-01-01

    Superhydrophobic materials, with surfaces possessing permanent or metastable non-wetted states, are of interest for a number of biomedical and industrial applications. Here we describe how electrospinning or electrospraying a polymer mixture containing a biodegradable, biocompatible aliphatic polyester (e.g., polycaprolactone and poly(lactide-co-glycolide)), as the major component, doped with a hydrophobic copolymer composed of the polyester and a stearate-modified poly(glycerol carbonate) affords a superhydrophobic biomaterial. The fabrication techniques of electrospinning or electrospraying provide the enhanced surface roughness and porosity on and within the fibers or the particles, respectively. The use of a low surface energy copolymer dopant that blends with the polyester and can be stably electrospun or electrosprayed affords these superhydrophobic materials. Important parameters such as fiber size, copolymer dopant composition and/or concentration, and their effects on wettability are discussed. This combination of polymer chemistry and process engineering affords a versatile approach to develop application-specific materials using scalable techniques, which are likely generalizable to a wider class of polymers for a variety of applications. PMID:26383018

  9. Dynamic air layer on textured superhydrophobic surfaces.

    Science.gov (United States)

    Vakarelski, Ivan U; Chan, Derek Y C; Marston, Jeremy O; Thoroddsen, Sigurdur T

    2013-09-03

    We provide an experimental demonstration that a novel macroscopic, dynamic continuous air layer or plastron can be sustained indefinitely on textured superhydrophobic surfaces in air-supersaturated water by a natural gas influx mechanism. This type of plastron is an intermediate state between Leidenfrost vapor layers on superheated surfaces and the equilibrium Cassie-Baxter wetting state on textured superhydrophobic surfaces. We show that such a plastron can be sustained on the surface of a centimeter-sized superhydrophobic sphere immersed in heated water and variations of its dynamic behavior with air saturation of the water can be regulated by rapid changes of the water temperature. The simple experimental setup allows for quantification of the air flux into the plastron and identification of the air transport model of the plastron growth. Both the observed growth dynamics of such plastrons and millimeter-sized air bubbles seeded on the hydrophilic surface under identical air-supersaturated solution conditions are consistent with the predictions of a well-mixed gas transport model.

  10. Durable Nanocomposites for Superhydrophobicity and Superoleophobicity

    Science.gov (United States)

    Steele, Adam

    Anti-wetting surfaces and materials have the potential for dramatic performance improvements such as drag reduction on marine vehicles and fluid power systems as well as anti-fouling on aircraft and wind turbines. Although a wide variety of synthetic superhydrophobic surfaces have been developed and investigated, several critical obstacles remain before industrial application can be realized, including: (1) large surface area application, (2) multi-liquid anti-wetting, (3) environmentally friendly compositions, (4) mechanical durability and adhesion, and (5) long-term performance. In this dissertation, nanocomposite coatings have been investigated to generate high performance anti-wetting surfaces that address these obstacles which may enable application on wind turbine blades. Solution processable materials were used which self-assemble to create anti-wetting nanocomposite surfaces upon spray coating and curing. As a result, the first superoleophobic nanocomposite, the first environmentally friendly superhydrophobic compositions, and the first highly durable superhydrophobic nanocomposite coatings were created. Furthermore, the mechanisms leading to this improved performance were studied.

  11. Structure Irregularity Impedes Drop Roll-Off at Superhydrophobic Surfaces

    DEFF Research Database (Denmark)

    Larsen, Simon Tylsgaard; Andersen, Nis Korsgaard; Søgaard, Emil

    2014-01-01

    We study water drop roll-off at superhydrophobic surfaces with different surface patterns. Superhydrophobic microcavity surfaces were fabricated in silicon and coated with 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS). For the more irregular surface patterns, the observed increase in roll...

  12. Layers of Porous Superhydrophobic Surfaces for Robust Water Repellency

    Science.gov (United States)

    Ahmadi, Farzad; Boreyko, Jonathan; Nature-Inspired Fluids; Interfaces Team

    2015-11-01

    In nature, birds exhibit multiple layers of superhydrophobic feathers that repel water. Inspired by bird feathers, we utilize porous superhydrophobic surfaces and compare the wetting and dewetting characteristics of a single surface to stacks of multiple surfaces. The superhydrophobic surfaces were submerged in water in a closed chamber. Pressurized gas was regulated to measure the critical pressure for the water to fully penetrate through the surfaces. In addition to using duck feathers, two-tier porous superhydrophobic surfaces were fabricated to serve as synthetic mimics with a controlled surface structure. The energy barrier for the wetting transition was modeled as a function of the number of layers and their orientations with respect to each other. Moreover, after partial impalement into a subset of the superhydrophobic layers, it was observed that a full dewetting transition was possible, which suggests that natural organisms can exploit their multiple layers to prevent irreversible wetting.

  13. A simple approach to fabricate stable superhydrophobic glass surfaces

    Science.gov (United States)

    Ji, Haiyan; Chen, Gang; Yang, Jin; Hu, Jie; Song, Haojie; Zhao, Yutao

    2013-02-01

    We present a facile method to fabricate superhydrophobic glass surface via one-step hydrothermal method and chemical modification. The etched glass surface shows the hierarchical textured morphology as well as the multiple scales of roughness and large numbers of nanorods and pores. The formation mechanism of the hierarchically structured surface is discussed in detail. After surface modification with vinyltriethoxysilane, the glass surface exhibits stable superhydrophobicity with a high contact angle of 155° and a low sliding angle of 5°. A water droplet of 10 μL can bounce away from the surface when it vertically hit the superhydrophobic glass surface. Moreover, the contact angle of the superhydrophobic glass surface under different pH values and storage time are measured to study the stability of the superhydrophobic property.

  14. What do we need for a superhydrophobic surface? A review on the recent progress in the preparation of superhydrophobic surfaces

    NARCIS (Netherlands)

    Li, X.; Reinhoudt, David; Crego Calama, Mercedes

    2007-01-01

    Superhydrophobic surfaces have drawn a lot of interest both in academia and in industry because of the self-cleaning properties. This critical review focuses on the recent progress (within the last three years) in the preparation, theoretical modeling, and applications of superhydrophobic surfaces.

  15. Biomimetic polymeric superhydrophobic surfaces and nanostructures: from fabrication to applications.

    Science.gov (United States)

    Wen, Gang; Guo, ZhiGuang; Liu, Weimin

    2017-03-09

    Numerous research studies have contributed to the development of mature superhydrophobic systems. The fabrication and applications of polymeric superhydrophobic surfaces have been discussed and these have attracted tremendous attention over the past few years due to their excellent properties. In general, roughness and chemical composition, the two most crucial factors with respect to surface wetting, provide the basic criteria for yielding polymeric superhydrophobic materials. Furthermore, with their unique properties and flexible configurations, polymers have been one of the most efficient materials for fabricating superhydrophobic materials. This review aims to summarize the most recent progress in polymeric superhydrophobic surfaces. Significantly, the fundamental theories for designing these materials will be presented, and the original methods will be introduced, followed by a summary of multifunctional superhydrophobic polymers and their applications. The principles of these methods can be divided into two categories: the first involves adding nanoparticles to a low surface energy polymer, and the other involves combining a low surface energy material with a textured surface, followed by chemical modification. Notably, surface-initiated radical polymerization is a versatile method for a variety of vinyl monomers, resulting in controlled molecular weights and low polydispersities. The surfaces produced by these methods not only possess superhydrophobicity but also have many applications, such as self-cleaning, self-healing, anti-icing, anti-bioadhesion, oil-water separation, and even superamphiphobic surfaces. Interestingly, the combination of responsive materials and roughness enhances the responsiveness, which allows the achievement of intelligent transformation between superhydrophobicity and superhydrophilicity. Nevertheless, surfaces with poor physical and chemical properties are generally unable to withstand the severe conditions of the outside world

  16. Validation of FRP Matting Requirements

    Science.gov (United States)

    2016-08-01

    conducted at the U.S. Air Force (USAF) Plant 42 Facility in Palmdale, California, revealed that FFM matting was not strong enough to withstand traffic...MTX-60 jumping jack compactors. The final lift was compacted with a self-propelled vibratory steel wheeled roller. The timing data for installing...to operate in the smaller craters. It was suggested to add a small steel wheel roller rather than use the jumping jack compactor. A steel wheel

  17. Fibrous Dysplasia Characterization Using Lacunarity Analysis.

    Science.gov (United States)

    Cordeiro, Mirna S; Backes, André R; Júnior, Antônio F Durighetto; Gonçalves, Elmar H G; de Oliveira, Jefferson X

    2016-02-01

    Fibrous dysplasia (FD) is a developmental anomaly in which the normal medullary space of the affected bone is replaced by fibro-osseous tissue. This condition is typically encountered in adolescents and young adults. It affects the maxillofacial region and it can often cause severe deformity and asymmetry. Therefore, accurate diagnosis is critical to determine the appropriate treatment of each case. In this sense, computed tomography (CT) is a relevant resource among the imaging techniques for correct diagnosis of this condition. Thus, in this paper, we propose to analyze fibrous dysplasia through its texture pattern. To accomplish this task, we propose to use lacunarity analysis, a multiscale method for describing patterns of spatial dispersion. Results indicated lower lacunarity values for fibrous dysplasia in comparison to normal bone samples, an indication that their texture images are more homogeneous, and a high separability between the classes when using principal component analysis (PCA) and decision trees for statistical analysis.

  18. Congenital fibrous hamartoma of the knee

    Energy Technology Data Exchange (ETDEWEB)

    Arioni, Cesare; Bellini, Carlo; Risso, Francesco Maria; Scopesi, Fabio; Serra, Giovanni [University of Genoa, Neonatal Pathology Service, Department of Paediatrics, Institute G. Gaslini, Genoa (Italy); Oddone, Mauro; Toma, Paolo [Institute G. Gaslini, Radiology Service, Genoa (Italy); Nozza, Paolo [Institute G. Gaslini, U. O. di Anatomia Patologica, Genoa (Italy)

    2006-05-15

    A full-term male infant presented at birth with a hard swelling of the left knee. The lemon-sized lesion was fixed to the underlying knee muscles, while the overlying skin was stretched and shiny; there was no bruit. Radiography, sonography and MRI suggested a soft-tissue tumour. After surgical excision, histology showed the presence of fibrous and mesenchymal tissue, with mature adipose tissue. Fibrous hamartoma of infancy was diagnosed. Among soft-tissue tumours, fibrous hamartoma of infancy is a rare and benign lesion, occurring in the first 2 years of life. The tumour mainly affects the trunk, axilla, and upper extremities. This infant had unique involvement of the knee. The treatment of choice is local excision. (orig.)

  19. Malignant fibrous histiocytoma with skeletal involvement

    Directory of Open Access Journals (Sweden)

    Takechi,Hideo

    1978-10-01

    Full Text Available Malignant fibrous histiocytoma of soft part is rather common but malignant fibrous histiocytoma of the bone is rarely encountered clinically. Authors present five cases of malignant fibrous histiocytoma with skeletal involvement and discuss their clinical course, x-ray findings and histological features. This tumor has marked tendency for local recurrence and metastasis. Other bone tumors such as giant cell tumor, aneurysmal bone cyst, non ossifying fibroma, osteosarcoma, fibrosarcoma of bone and metastatic cancer can be excluded by several characteristic findings observed in x-rays as well as histopathological features. All information on the patient should be carefully analysed, because it is difficult to decide whether bone involvement is primary or secondary. Four out of five cases definitely originated within the bone.

  20. Transparent conducting film: Effect of mechanical stretching to optical and electrical properties of carbon nanotube mat

    Indian Academy of Sciences (India)

    Tsuyoshi Saotome; Hansang Kim; David Lashmore; H Thomas Hahn

    2011-07-01

    We describe in this paper a transparent conducting film (TCF). It is a fibrous layer of multiwalled carbon nanotubes (MWNTs), labeled a dilute CNT mat, that was prepared and unidirectionally stretched to improve both the optical and electrical properties. After stretching by 80% strain, transmittance at 550 nm wavelength was improved by 37% and sheet resistance was reduced to 71% of the original value. The improvement of the transmittance can be explained by increased area of the CNT mat after stretch, and the reduced sheet resistance can be explained by increased density of the CNT alignment in lateral direction due to contraction. Based on the microscopic observation before and after stretch, models to describe the phenomena are proposed. By further expanding on this method, it may be possible to obtain a transparent conducting carbon nanotube film which is crack-resistant for solar cell applications.

  1. Fibrous Protein Structures: Hierarchy, History and Heroes.

    Science.gov (United States)

    Squire, John M; Parry, David A D

    2017-01-01

    During the 1930s and 1940s the technique of X-ray diffraction was applied widely by William Astbury and his colleagues to a number of naturally-occurring fibrous materials. On the basis of the diffraction patterns obtained, he observed that the structure of each of the fibres was dominated by one of a small number of different types of molecular conformation. One group of fibres, known as the k-m-e-f group of proteins (keratin - myosin - epidermin - fibrinogen), gave rise to diffraction characteristics that became known as the α-pattern. Others, such as those from a number of silks, gave rise to a different pattern - the β-pattern, while connective tissues yielded a third unique set of diffraction characteristics. At the time of Astbury's work, the structures of these materials were unknown, though the spacings of the main X-ray reflections gave an idea of the axial repeats and the lateral packing distances. In a breakthrough in the early 1950s, the basic structures of all of these fibrous proteins were determined. It was found that the long protein chains, composed of strings of amino acids, could be folded up in a systematic manner to generate a limited number of structures that were consistent with the X-ray data. The most important of these were known as the α-helix, the β-sheet, and the collagen triple helix. These studies provided information about the basic building blocks of all proteins, both fibrous and globular. They did not, however, provide detailed information about how these molecules packed together in three-dimensions to generate the fibres found in vivo. A number of possible packing arrangements were subsequently deduced from the X-ray diffraction and other data, but it is only in the last few years, through the continued improvements of electron microscopy, that the packing details within some fibrous proteins can now be seen directly. Here we outline briefly some of the milestones in fibrous protein structure determination, the role of the

  2. Enzymes in bast fibrous plant processing.

    Science.gov (United States)

    Kozlowski, Ryszard; Batog, Jolanta; Konczewicz, Wanda; Mackiewicz-Talarczyk, Maria; Muzyczek, Malgorzata; Sedelnik, Natalia; Tanska, Bogumila

    2006-05-01

    The program COST Action 847 Textile Quality and Biotechnology (2000-2005) has given an excellent chance to review the possibilities of the research, aiming at development of the industrial application of enzymes for bast fibrous plant degumming and primary processing. The recent advancements in enzymatic processing of bast fibrous plants (flax, hemp, jute, ramie and alike plants) and related textiles are given. The performance of enzymes in degumming, modification of bast fibres, roving, yarn, related fabrics as well as enzymatic bonding of lignocellulosic composites is provided.

  3. A case of intracranial malignant fibrous histiocytoma

    Directory of Open Access Journals (Sweden)

    Amir Hossein Sarrami

    2011-01-01

    Full Text Available We describe a case of intracranial malignant fibrous histiocytoma which had infiltrated pons, cerebellum and basal surface of left temporal lobe without any visible mass. The patient presented with a sudden loss of consciousness and vomiting. Clinical findings, laboratory tests, imaging and examination of the cerebrospinal fluid tended to establish the diagnosis of an infectious condition than a malignancy. Without any response to the antibiotics and with a progressive deterioration of neurologic and mental condition, the patient died after 20 days. In the autopsy, histological and immunohistochemical study of the brain revealed the diagnosis of malignant fibrous histiocytoma (MFH.

  4. Atypical cutaneous fibrous histiocytoma: an unusual and misleading variant of fibrous histiocytoma.

    Science.gov (United States)

    Ben Abdelkrim, Soumaya; Belajouza, Colondane; Jomaa, Wafa; Beizig, Nadia; Ben Said, Zeineb; Mokni, Moncef; Nouira, Rafia; Sriha, Badreddine

    2011-01-01

    Atypical fibrous histiocytoma is a distinctive variant of cutaneous fibrous histiocytoma, which is often mistaken histologically for sarcoma and which have a tendency to recur locally and a capacity to metastasize, although very rarely. We report a new case of atypical cutaneous fibrous histiocytoma in a 31-year-old man who presented with a recurrent polypoid nodule on the abdominal wall. The diagnosis was made on the basis of morphological and immunohistochemical findings. We discuss through this case and a review of the literature pathological and evolutive features and diagnostic difficulties of this entity.

  5. Atypical Cutaneous Fibrous Histiocytoma: An Unusual and Misleading Variant of Fibrous Histiocytoma

    Directory of Open Access Journals (Sweden)

    Soumaya Ben Abdelkrim

    2011-01-01

    Full Text Available Atypical fibrous histiocytoma is a distinctive variant of cutaneous fibrous histiocytoma, which is often mistaken histologically for sarcoma and which have a tendency to recur locally and a capacity to metastasize, although very rarely. We report a new case of atypical cutaneous fibrous histiocytoma in a 31-year-old man who presented with a recurrent polypoid nodule on the abdominal wall. The diagnosis was made on the basis of morphological and immunohistochemical findings. We discuss through this case and a review of the literature pathological and evolutive features and diagnostic difficulties of this entity.

  6. Enhanced dechlorination of trichloroethylene using electrospun polymer nanofibrous mats immobilized with iron/palladium bimetallic nanoparticles.

    Science.gov (United States)

    Ma, Hui; Huang, Yunpeng; Shen, Mingwu; Guo, Rui; Cao, Xueyan; Shi, Xiangyang

    2012-04-15

    Fe/Pd bimetallic nanoparticles (NPs) have held great promise for treating trichloroethylene (TCE)-contaminated groundwater, without the accumulation of chlorinated intermediates. However, the conventionally used colloidal Fe/Pd NPs usually aggregate rapidly, resulting in a reduced reactivity. To reduce the particle aggregation, we employed electrospun polyacrylic acid (PAA)/polyvinyl alcohol (PVA) polymer nanofibers as a nanoreactor to immobilize Fe/Pd bimetallic NPs. In the study, the water-stable PAA/PVA nanofibrous mats were complexed with Fe (III) ions via the binding with the free carboxyl groups of PAA for subsequent formation and immobilization of zero-valent iron (ZVI) NPs. Fe/Pd bimetallic NPs were then formed by the partial reduction of Pd(II) ions with ZVI NPs. The formed electrospun nanofibrous mats containing Fe/Pd bimetallic NPs with a diameter of 2.8 nm were characterized by scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, thermogravimetric analysis, and inductively coupled plasma-atomic emission spectroscopy. The Fe/Pd NP-containing electrospun PAA/PVA nanofibrous mats exhibited higher reactivity than that of the ZVI NP-containing mats or colloidal Fe/Pd NPs in the dechlorination of trichloroethylene (TCE), which was used as a model contaminant. With the high surface area to volume ratio, high porosity, and great reusability of the fibrous mats immobilized with the bimetallic NPs, the composite nanofibrous mats should be amenable for applications in remediation of various environmental contaminants. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. How to repel hot water from a superhydrophobic surface?

    KAUST Repository

    Yu, Zhejun

    2014-01-01

    Superhydrophobic surfaces, with water contact angles greater than 150° and slide angles less than 10°, have attracted a great deal of attention due to their self-cleaning ability and excellent water-repellency. It is commonly accepted that a superhydrophobic surface loses its superhydrophobicity in contact with water hotter than 50 °C. Such a phenomenon was recently demonstrated by Liu et al. [J. Mater. Chem., 2009, 19, 5602], using both natural lotus leaf and artificial leaf-like surfaces. However, our work has shown that superhydrophobic surfaces maintained their superhydrophobicity, even in water at 80 °C, provided that the leaf temperature is greater than that of the water droplet. In this paper, we report on the wettability of water droplets on superhydrophobic thin films, as a function of both their temperatures. The results have shown that both the water contact and slide angles on the surfaces will remain unchanged when the temperature of the water droplet is greater than that of the surface. The water contact angle, or the slide angle, will decrease or increase, however, with droplet temperatures increasingly greater than that of the surfaces. We propose that, in such cases, the loss of superhydrophobicity of the surfaces is caused by evaporation of the hot water molecules and their condensation on the cooler surface. © 2014 the Partner Organisations.

  8. Wettability and Contact Time on a Biomimetic Superhydrophobic Surface

    Directory of Open Access Journals (Sweden)

    Yunhong Liang

    2017-03-01

    Full Text Available Inspired by the array microstructure of natural superhydrophobic surfaces (lotus leaf and cicada wing, an array microstructure was successfully constructed by high speed wire electrical discharge machining (HS-WEDM on the surfaces of a 7075 aluminum alloy without any chemical treatment. The artificial surfaces had a high apparent contact angle of 153° ± 1° with a contact angle hysteresis less than 5° and showed a good superhydrophobic property. Wettability, contact time, and the corresponding superhydrophobic mechanism of artificial superhydrophobic surface were investigated. The results indicated that the micro-scale array microstructure was an important factor for the superhydrophobic surface, while different array microstructures exhibited different effects on the wettability and contact time of the artificial superhydrophobic surface. The length (L, interval (S, and height (H of the array microstructure are the main influential factors on the wettability and contact time. The order of importance of these factors is H > S > L for increasing the apparent contact angle and reducing the contact time. The method, using HS-WEDM to fabricate superhydrophobic surface, is simple, low-cost, and environmentally friendly and can easily control the wettability and contact time on the artificial surfaces by changing the array microstructure.

  9. Water Penetration through a Superhydrophobic Mesh During a Drop Impact.

    Science.gov (United States)

    Ryu, Seunggeol; Sen, Prosenjit; Nam, Youngsuk; Lee, Choongyeop

    2017-01-06

    When a water drop impacts a mesh having submillimeter pores, a part of the drop penetrates through the mesh if the impact velocity is sufficiently large. Here we show that different surface wettability, i.e., hydrophobicity and superhydrophobicity, leads to different water penetration dynamics on a mesh during drop impact. We show, despite the water repellence of a superhydrophobic surface, that water can penetrate a superhydrophobic mesh more easily (i.e., at a lower impact velocity) over a hydrophobic mesh via a penetration mechanism unique to a superhydrophobic mesh. On a superhydrophobic mesh, the water penetration can occur during the drop recoil stage, which appears at a lower impact velocity than the critical impact velocity for water penetration right upon impact. We propose that this unique water penetration on a superhydrophobic mesh can be attributed to the combination of the hydrodynamic focusing and the momentum transfer from the water drop when it is about to bounce off the surface, at which point the water drop retrieves most of its kinetic energy due to the negligible friction on superhydrophobic surfaces.

  10. Multifunctional polymer nano-composite based superhydrophobic surface

    Science.gov (United States)

    Maitra, Tanmoy; Asthana, Ashish; Buchel, Robert; Tiwari, Manish K.; Poulikakos, Dimos

    2014-11-01

    Superhydrophobic surfaces become desirable in plethora of applications in engineering fields, automobile industry, construction industries to name a few. Typical fabrication of superhydrophobic surface consists of two steps: first is to create rough morphology on the substrate of interest, followed by coating of low energy molecules. However, typical exception of the above fabrication technique would be direct coating of functional polymer nanocomposites on substrate where superhydrophobicity is needed. Also in this case, the use of different nanoparticles in the polymer matrix can be exploited to impart multi-functional properties to the superhydrophobic coatings. Herein, different carbon nanoparticles like graphene nanoplatelets (GNP), carbon nanotubes (CNT) and carbon black (CB) are used in fluropolymer matrix to prepare superhydrophobic coatings. The multi-functional properties of coatings are enhanced by combining two different carbon fillers in the matrix. The aforementioned superhydrophobic coatings have shown high electrical conductivity and excellent droplet meniscus impalement resistance. Simultaneous superhydrophobic and oleophillic character of the above coating is used to separate mineral oil and water through filtration of their mixture. Swiss National Science Foundation (SNF) Grant 200021_135479.

  11. Clinicopathologic characteristics of fibrous mass-forming chronic pancreatitis

    Institute of Scientific and Technical Information of China (English)

    常雪姣

    2013-01-01

    Objective To investigate clinicopathological features of fibrous mass-forming chronic pancreatitis (FMCP) ,to compare clinicopathological and immunohistochemical characteristics between autoimmune pancreatitis (AIP) and fibrous mass-forming non-autoimmune pancreatitis

  12. Cervical spinal monostotic fibrous dysplasia: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ok Hwa [Dept. of Radiology, Haeundae Paik Hospital, Inje University College of Medicine, Busan (Korea, Republic of)

    2013-09-15

    Monostotic fibrous dysplasia of the cervical vertebra is quite unusual. The author reports a case of monostotic fibrous dysplasia affecting the second cervical vertebra with descriptions from the CT, MR and bone scanning findings.

  13. Optic nerve decompression for orbitofrontal fibrous dysplasia.

    Science.gov (United States)

    Abe, Takumi; Sato, Kaneshige; Otsuka, Takaharu; Kawamura, Noriyoshi; Shimazu, Motohiko; Izumiyama, Hitoshi; Matsumoto, Kiyoshi

    2002-08-01

    Orbitofrontal fibrous dysplasia often involves the bony orbit and the optic canal. Although fibrous dysplasia reportedly produces compression of the optic nerve leading to visual distrubances, optic nerve decompression in patients without clinical signs of optic neuropathy is still controversial. We describe two patients with orbitofrontal fibrous dysplasia without signs of visual disturbance and one patient with McCune-Albright syndrome and progressive visual impairment. Optic nerve decompression was performed prophylactically for two patients and therapeutically for one patient through the transcranial extradural route. Dystopias and craniofacial deformities induced by fibrous dysplasia also were corrected. The micropressure suction-irrigation system was especially effective for decreasing heat transfer and thereby preventing thermal injury of the optic nerve. The orbitofrontal area was reconstructed from cranial bone, iliac bone, and ribs. Postoperative follow-up revealed no disturbances in visual function and no evidence of cerebrospinal fluid leakage. These findings suggest that optic nerve decompression may be effective in preventing visual disturbances with minimal risk of other neurological sequelae. Subsequent orbital reconstruction yielded satisfactory cosmetic results.

  14. Prophylactic intramedullary nailing in monostotic fibrous dysplasia.

    Science.gov (United States)

    Demiralp, Bahtiyar; Ozturk, Cagatay; Ozturan, Kutay; Sanisoglu, Yavuz S; Cicek, Ilker E; Erler, Kaan

    2008-06-01

    Fibrous dysplasia of bone is an enigma with no known cure. Treatment currently consists of curettage and bone-grafting in an attempt to eradicate the lesion and to prevent progressive deformity. This study presents the results of prophylactic intramedullary nailing in 10 patients with monostotic fibrous dysplasia, pain increasing with movement, and scintigraphically established activity. Ten patients with monostotic fibrous dysplasia in their upper or lower extremities treated between 2001 and 2003 were included in the study. Seven patients were male and 3 were female; their mean age was 26.9 years. The mean duration of follow-up was 33.5 months. Closed intramedullary nail without reaming was used in all cases. Bone grafting was not performed. Patients were allowed full weight bearing on the affected extremities on the second postoperative day. Mean VAS for functional pain was 5.33 +/- 0.65 preoperatively and 2.26 +/- 0.57 at final follow-up (p < 0.05). Radiographs showed no changes in lesion size, and the intramedullary fixation appeared to be stable. Prophylactic intramedullary nailing appeared to be beneficial in monostotic fibrous dysplasia with scintigraphically proven activity and functional pain. It also avoids problems that may occur following pathological fracture.

  15. Giant solitary fibrous tumour of the liver

    NARCIS (Netherlands)

    T. Terkivatan (Türkan); M. Kliffen (Mike); J.H.W. de Wilt (Johannes); A.N. van Geel (Albert); A.M.M. Eggermont (Alexander); C. Verhoef (Kees)

    2006-01-01

    textabstractBackground: Solitary fibrous tumour (SFT) is an uncommon mesenchymal neoplasm that most frequently affects the pleura, although it has been reported with increasing frequency in various other sites such as in the peritoneum, pericardium and in non-serosal sites such as lung parenchyma,

  16. Craniofacial fibrous dysplasia: A 10-case series.

    Science.gov (United States)

    Couturier, A; Aumaître, O; Gilain, L; Jean, B; Mom, T; André, M

    2017-09-01

    Fibrous dysplasia of bone is a rare sporadic benign congenital condition in which normal cancellous bone is replaced by fibro-osseous tissue with immature osteogenesis. Sarcomatous transformation is exceptional. Lesions may involve one bone (monostotic) or several (polyostotic). Fibrous dysplasia may be associated with café-au-lait skin macules and endocrinopathy in McCune-Albright syndrome, or with myxoma in Mazabraud's syndrome. We report ten cases of patients followed up for craniofacial fibrous dysplasia in our center between 2010 and 2015. Mean age was 43 years (range, 10-72 years). Clinical symptoms comprised headache (n=3) and sensorineural disorder: recurrent anterior uveitis (n=1), visual acuity loss, epiphora and vestibular syndrome (n=1), and hearing loss (n=1). All cases were monostotic. The sphenoid bone was most commonly involved (n=5), followed by the ethmoid (n=1), frontal (n=1), fronto-ethmoid (n=1), temporal (n=1) and fronto-ethmoido-sphenoid (n=1) bones. Five patients were treated with intravenous pamidronate, a bisphosphonate: evolution was favorable for 3 of them at 1-6 months after treatment initiation, with resolution of headache or vestibular syndrome; the other 2 patients were stable. Two patients were operated on. Diagnosis of craniofacial fibrous dysplasia should be considered in case of headache, neuralgia, sensory disorder, functional disorder or infectious ENT complications. A medico-surgical approach is useful for these patients. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  17. Solitary fibrous tumour of the vagus nerve.

    Science.gov (United States)

    Scholsem, Martin; Scholtes, Felix

    2012-04-01

    We describe the complete removal of a foramen magnum solitary fibrous tumour in a 36-year-old woman. It originated on a caudal vagus nerve rootlet, classically described as the 'cranial' accessory nerve root. This ninth case of immunohistologically confirmed cranial or spinal nerve SFT is the first of the vagus nerve.

  18. Topology optimization of robust superhydrophobic surfaces

    DEFF Research Database (Denmark)

    Cavalli, Andrea; Bøggild, Peter; Okkels, Fridolin

    2013-01-01

    the space between the posts, we search for an optimal post cross-section that minimizes the vertical displacement of the liquid–air interface at the base of the drop when a pressure difference is applied. Topology optimisation proves effective in this framework, showing that posts with a branching cross......-section are optimal, which is consistent with several biologic strategies to achieve superhydrophobicity. Through a filtering technique, we can also control the characteristic length scale of the optimal design, thus obtaining geometries feasible via standard lithography....

  19. Anisotropic flow in striped superhydrophobic channels

    CERN Document Server

    Zhou, Jiajia; Schmid, Friederike; Vinogradova, Olga I

    2012-01-01

    We report results of dissipative particle dynamics simulations and develop a semi-analytical theory and of an anisotropic flow in a parallel-plate channel with two superhydrophobic striped walls. Our approach is valid for any local slip at the gas sectors and an arbitrary distance between the plates, ranging from a thick to a thin channel. It allows us to optimize area fractions, slip lengths, channel thickness and texture orientation to maximize a transverse flow. Our results may be useful for extracting effective slip tensors from global measurements, such as the permeability of a channel, in experiments or simulations, and may also find applications in passive microfluidic mixing.

  20. Superhydrophobic Materials Technology-PVC Bonding Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, Scott R. [Oak Ridge National Laboratory; Efird, Marty [VeloxFlow, LLC

    2013-05-03

    The purpose of the technology maturation project was to develop an enhanced application technique for applying diatomaceous earth with pinned polysiloxane oil to PVC pipes and materials. The oil infiltration technique is applied as a spray of diluted oil in a solvent onto the superhydrophobic diatomaceous earth substrate. This makes the surface take on the following characteristics: wet-cleanable; anti-biofouling; waterproof; and anti-corrosion. The project involved obtaining input and supplies from VeloxFlow and the development of successful techniques that would quickly result in a commercial license agreement with VeloxFlow and other companies that use PVC materials in a variety of other fields of use.

  1. Capillary origami and superhydrophobic membrane surfaces

    Science.gov (United States)

    Geraldi, N. R.; Ouali, F. F.; Morris, R. H.; McHale, G.; Newton, M. I.

    2013-05-01

    Capillary origami uses surface tension to fold and shape solid films and membranes into three-dimensional structures. It uses the fact that solid surfaces, no matter how hydrophobic, will tend to adhere to and wrap around the surface of a liquid. In this work, we report that a superhydrophobic coating can be created, which can completely suppress wrapping as a contacting water droplet evaporates. We also show that using a wetting azeotropic solution of allyl alcohol, which penetrates the surface features, can enhance liquid adhesion and create more powerful Capillary Origami. These findings create the possibility of selectively shaping membrane substrates.

  2. Plastron properties of a superhydrophobic surface

    Science.gov (United States)

    Shirtcliffe, Neil J.; McHale, Glen; Newton, Michael I.; Perry, Carole C.; Pyatt, F. Brian

    2006-09-01

    Most insects and spiders drown when submerged during flooding or tidal inundation, but some are able to survive and others can remain submerged indefinitely without harm. Many achieve this by natural adaptations to their surface morphology to trap films of air, creating plastrons which fix the water-vapor interface and provide an incompressible oxygen-carbon dioxide exchange surface. Here the authors demonstrate how the surface of an extremely water-repellent foam mimics this mechanism of underwater respiration and allows direct extraction of oxygen from aerated water. The biomimetic principle demonstrated can be applied to a wide variety of man-made superhydrophobic materials.

  3. Dropwise condensation on superhydrophobic surfaces with two-tier roughness

    Science.gov (United States)

    Chen, Chuan-Hua; Cai, Qingjun; Tsai, Chialun; Chen, Chung-Lung; Xiong, Guangyong; Yu, Ying; Ren, Zhifeng

    2007-04-01

    Dropwise condensation can enhance heat transfer by an order of magnitude compared to film condensation. Superhydrophobicity appears ideal to promote continued dropwise condensation which requires rapid removal of condensate drops; however, such promotion has not been reported on engineered surfaces. This letter reports continuous dropwise condensation on a superhydrophobic surface with short carbon nanotubes deposited on micromachined posts, a two-tier texture mimicking lotus leaves. On such micro-/nanostructured surfaces, the condensate drops prefer the Cassie state which is thermodynamically more stable than the Wenzel state. With a hexadecanethiol coating, superhydrophobicity is retained during and after condensation and rapid drop removal is enabled.

  4. Superhydrophobic Ceramic Coatings by Solution Precursor Plasma Spray

    Science.gov (United States)

    Cai, Yuxuan; Coyle, Thomas W.; Azimi, Gisele; Mostaghimi, Javad

    2016-04-01

    This work presents a novel coating technique to manufacture ceramic superhydrophobic coatings rapidly and economically. A rare earth oxide (REO) was selected as the coating material due to its hydrophobic nature, chemical inertness, high temperature stability, and good mechanical properties, and deposited on stainless steel substrates by solution precursor plasma spray (SPPS). The effects of various spraying conditions including standoff distance, torch power, number of torch passes, types of solvent and plasma velocity were investigated. The as-sprayed coating demonstrated a hierarchically structured surface topography, which closely resembles superhydrophobic surfaces found in nature. The water contact angle on the SPPS superhydrophobic coating was up to 65% higher than on smooth REO surfaces.

  5. MatLab Script and Functional Programming

    Science.gov (United States)

    Shaykhian, Gholam Ali

    2007-01-01

    MatLab Script and Functional Programming: MatLab is one of the most widely used very high level programming languages for scientific and engineering computations. It is very user-friendly and needs practically no formal programming knowledge. Presented here are MatLab programming aspects and not just the MatLab commands for scientists and engineers who do not have formal programming training and also have no significant time to spare for learning programming to solve their real world problems. Specifically provided are programs for visualization. The MatLab seminar covers the functional and script programming aspect of MatLab language. Specific expectations are: a) Recognize MatLab commands, script and function. b) Create, and run a MatLab function. c) Read, recognize, and describe MatLab syntax. d) Recognize decisions, loops and matrix operators. e) Evaluate scope among multiple files, and multiple functions within a file. f) Declare, define and use scalar variables, vectors and matrices.

  6. Bentonite mat demonstration. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Serrato, M.G.

    1994-12-30

    The Bentonite Mat Demonstration was developed to provide the Environmental Restoration Department with field performance characteristics and engineering data for an alternative closure cover system configuration. The demonstration was initiated in response to regulatory concerns regarding the use of an alternative cover system for future design configurations. These design considerations are in lieu of the US Environmental Protection Agency (EPA) Recommended Design for Closure Cover Systems and specifically a single compacted kaolin clay layer with a hydraulic conductivity of 1 {times} 10{sup {minus}7} cm/sec. This alternative configuration is a composite geosynthetic material hydraulic barrier consisting from bottom to top: 2 ft compacted sandy clay layer (typical local Savannah River Site soil type) that is covered by a bentonite mat--geosynthetic clay liner (GCL) and is overlaid by a 40 mil High Density Polyethylene (HDPE) geomembrane--flexible membrane liner. This effort was undertaken to obtain and document the necessary field performance/engineering data for future designs and meet regulatory technical requirements for an alternative cover system configuration. The composite geosynthetic materials hydraulic barrier is the recommended alternative cover system configuration for containment of hazardous and low level radiological waste layers that have a high potential of subsidence to be used at the Savannah River Site (SRS). This alternative configuration mitigates subsidence effects in providing a flexible, lightweight cover system to maintain the integrity of the closure. The composite geosynthetic materials hydraulic barrier is recommended for the Sanitary Landfill and Low Level Radiological Waste Disposal Facility (LLRWDF) Closures.

  7. Superhydrophobic Behavior on Nano-structured Surfaces

    Science.gov (United States)

    Schaeffer, Daniel

    2008-05-01

    Superhydrophobic behavior is observed in natural occurrences and has been thoroughly studied over the past few years. Water repellant properties on uniform arrays of vertically aligned nano-cones were investigated to determine the highest achievable contact angle (a measure of water drop repellency), which is measured from the reference plane on which the water drop sits to the tangent line of the point at which the drop makes contact with the reference plane. At low aspect ratios (height vs. width of the nano-cones), surface tension pulls the water into the nano-cone array, resulting in a wetted surface. Higher aspect ratios reverse the effect of the surface tension, resulting in a larger contact angle that causes water drops to roll off the surface. Fiber drawing, bundling, and redrawing are used to produce the structured array glass composite surface. Triple-drawn fibers are fused together, annealed, and sliced into thin wafers. The surface of the composite glass is etched to form nano-cones through a differential etching process and then coated with a fluorinated self-assembled monolayer (SAM). Cone aspect ratios can be varied through changes in the chemistry and concentration of the etching acid solution. Superhydrophobic behavior occurs at contact angles >150 and it is predicted and measured that optimal behavior is achieved when the aspect ratio is 4:1, which displays contact angles >=175 .

  8. A Nano-modified superhydrophobic membrane

    Directory of Open Access Journals (Sweden)

    Antonio Ferreira Ávila

    2013-06-01

    Full Text Available This paper focuses on the synthesis of super-hydrophobic membranes. The polymer used in this research is polystyrene (PS, which has low surface energy but not low enough to be characterized as a superhydrophobic material. As hydrophobicity is based on low energy surface and surface roughness, the electrospinning technique was selected as the manufacturing technique. N, N' dimethylformamide (DMF was employed as the PS solvent. Two groups of PS/DMF solutions were investigated i.e. 20/80 and 35/65. To increase even more the hydrophobicity, nanoparticles of silica, graphene, cadmium, and zinc were dispersed into the PS/DMF solutions. In contrast to results previous published in literature, the PS/DMF weight ratio of 20/80 led to water contact angles (WCA of 148º, which is higher than the contact angle for the 35/65 ratio, i.e. 143º. This fact seems to be due to the presence of non-evaporated solvent into the PS surface as the 35/65 solution was more viscous. The WCA for membranes with 0.5 wt. (% of graphene reached 152º, 149º-153º for membranes with nanosilica addition, 151º with 5.0 wt. (% CdS, and 153º, 163º and 168º with the addition of 5 wt. (%, 10 wt. (% and 15 wt. (% of ZnS, respectively.

  9. Anti-icing performance of superhydrophobic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Farhadi, S.; Farzaneh, M. [CIGELE/INGIVRE, Department of Applied Sciences, Universite du Quebec a Chicoutimi, 555 University blvd., Saguenay, PQ, G7H 2B1 (Canada); Kulinich, S.A., E-mail: skulinic@uqac.ca [CIGELE/INGIVRE, Department of Applied Sciences, Universite du Quebec a Chicoutimi, 555 University blvd., Saguenay, PQ, G7H 2B1 (Canada)

    2011-05-01

    This article studies the anti-ice performance of several micro/nano-rough hydrophobic coatings with different surface chemistry and topography. The coatings were prepared by spin-coating or dip coating and used organosilane, fluoropolymer or silicone rubber as a top layer. Artificially created glaze ice, similar to the naturally accreted one, was deposited on the nanostructured surfaces by spraying supercooled water microdroplets (average size {approx}80 {mu}m) in a wind tunnel at subzero temperature (-10 deg. C). The ice adhesion strength was evaluated by spinning the samples in a centrifuge at constantly increasing speed until ice delamination occurred. The results show that the anti-icing properties of the tested materials deteriorate, as their surface asperities seem to be gradually broken during icing/de-icing cycles. Therefore, the durability of anti-icing properties appears to be an important point for further research. It is also shown that the anti-icing efficiency of the tested superhydrophobic surfaces is significantly lower in a humid atmosphere, as water condensation both on top and between surface asperities takes place, leading to high values of ice adhesion strength. This implies that superhydrophobic surfaces may not always be ice-phobic in the presence of humidity, which can limit their wide use as anti-icing materials.

  10. Effects of mat characteristics on plantar pressure patterns and perceived mat properties during landing in gymnastics.

    Science.gov (United States)

    Pérez-Soriano, Pedro; Llana-Belloch, Salvador; Morey-Klapsing, Gaspar; Perez-Turpin, Jose Antonio; Cortell-Tormo, Juan Manuel; van den Tillaar, Roland

    2010-11-01

    Shock absorption and stability during landings is provided by both, gymnast ability and mat properties. The aims of this study were to determine the influence of different mat constructions on their energy absorption and stability capabilities, and to analyse how these properties affect gymnast's plantar pressures as well as subjective mat perception during landing. Six mats were tested using a standard mechanical drop test. In addition, plantar pressures and subjective perception during landing were obtained from 15 expert gymnasts. The different mats influenced plantar pressures and gymnasts' subjective perception during landing of gymnasts. Significant correlations between plantar pressures at the medial metatarsal and lateral metatarsal zones of the gymnasts' feet with the different shock absorption characteristics of the mats were found. However, subjective perception tests were not able to discriminate mat functionality between the six mats as no significant correlations between the mechanical mat properties with the subjective perception of these properties were found. This study demonstrated that plantar pressures are a useful tool for discriminating different landing mats. Using similar approaches, ideally including kinematics as well, could help us in our understanding about the influences of different mats upon gymnast-mat interaction.

  11. Superhydrophobic-like tunable droplet bouncing on slippery liquid interfaces

    Science.gov (United States)

    Hao, Chonglei; Li, Jing; Liu, Yuan; Zhou, Xiaofeng; Liu, Yahua; Liu, Rong; Che, Lufeng; Zhou, Wenzhong; Sun, Dong; Li, Lawrence; Xu, Lei; Wang, Zuankai

    2015-01-01

    Droplet impacting on solid or liquid interfaces is a ubiquitous phenomenon in nature. Although complete rebound of droplets is widely observed on superhydrophobic surfaces, the bouncing of droplets on liquid is usually vulnerable due to easy collapse of entrapped air pocket underneath the impinging droplet. Here, we report a superhydrophobic-like bouncing regime on thin liquid film, characterized by the contact time, the spreading dynamics, and the restitution coefficient independent of underlying liquid film. Through experimental exploration and theoretical analysis, we demonstrate that the manifestation of such a superhydrophobic-like bouncing necessitates an intricate interplay between the Weber number, the thickness and viscosity of liquid film. Such insights allow us to tune the droplet behaviours in a well-controlled fashion. We anticipate that the combination of superhydrophobic-like bouncing with inherent advantages of emerging slippery liquid interfaces will find a wide range of applications. PMID:26250403

  12. Manufacturing of Superhydrophobic Surfaces with Nanoscale and Microscale Features

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-06-01

    This factsheet describes a research project that will develop a technology that will enable nanoscale and microscale superhydrophobic (SHP) features to be imaged onto surfaces for the high-volume manufacturing of water-repellent components and coatings.

  13. Contact line and contact angle dynamics in superhydrophobic channels.

    Science.gov (United States)

    Zhang, Junfeng; Kwok, Daniel Y

    2006-05-23

    The dynamics of the wetting and movement of a three-phase contact line confined between two superhydrophobic surfaces were studied using a mean-field free-energy lattice Boltzmann model. Principle features of superhydrophobic surfaces, such as trapped vapor/air between rough microstructures, high contact angles, reduced contact angle hysteresis, and low resistance to fluid flow, were all observed. Movement of the three-phase contact line over a well-patterned superhydrophobic surface displays a periodic stick-jump-slip behavior, while the dynamic contact angle changes accordingly from maximum to minimum. Two regimes were found for the flow velocity as a function of surface roughness and can be related directly to the balance between driving force and flow resistance. This work provides a better understanding of dynamic wetting and fluid flow behaviors over superhydrophobic surfaces and hence could be useful in related applications.

  14. Superhydrophobic alumina surface based on stearic acid modification

    Energy Technology Data Exchange (ETDEWEB)

    Feng Libang, E-mail: lepond@hotmail.com [School of Mechatronic Engineering, Lanzhou Jiaotong University, Lanzhou 730070 (China); Zhang Hongxia; Mao Pengzhi; Wang Yanping; Ge Yang [School of Mechatronic Engineering, Lanzhou Jiaotong University, Lanzhou 730070 (China)

    2011-02-15

    A novel superhydrophobic alumina surface is fabricated by grafting stearic acid layer onto the porous and roughened aluminum film. The chemical and phase structure, morphology, and the chemical state of the atoms at the superhydrophobic surface were investigated by techniques as FTIR, XRD, FE-SEM, and XPS, respectively. Results show that a super water-repellent surface with a contact angle of 154.2{sup o} is generated. The superhydrophobic alumina surface takes on an uneven flowerlike structure with many nanometer-scale hollows distribute in the nipple-shaped protrusions, and which is composed of boehmite crystal and {gamma}-Al{sub 2}O{sub 3}. Furthermore, the roughened and porous alumina surface is coated with a layer of hydrophobic alkyl chains which come from stearic acid molecules. Therefore, both the roughened structure and the hydrophobic layer endue the alumina surface with the superhydrophobic behavior.

  15. Method of making superhydrophobic/superoleophilic paints, epoxies, and composites

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, John T.; Hunter, Scott Robert

    2016-05-10

    Superhydrophobic paints and epoxies comprising superoleophilic particles and surfaces and methods of making the same are described. The superoleophilic particles can include porous particles having a hydrophobic coating layer deposited thereon. superoleophilic particles.

  16. Durability of hydrophobic coatings for superhydrophobic aluminum oxide

    Science.gov (United States)

    Jenner, Elliot; Barbier, Charlotte; D'Urso, Brian

    2013-10-01

    Robust and easily produced superhydrophobic surfaces are of great interest for mechanical applications, including drag reduction and MEMS. We produce novel superhydrophobic surfaces with several different coatings and tested the durability of each of these coatings with respect to long term immersion in water in order to determine the most long-lasting surface preparation. A pair of combinations of spin on polymers, surface features, and adhesion promoters was found that provide long term durability.

  17. Robust biomimetic-structural superhydrophobic surface on aluminum alloy.

    Science.gov (United States)

    Li, Lingjie; Huang, Tao; Lei, Jinglei; He, Jianxin; Qu, Linfeng; Huang, Peiling; Zhou, Wei; Li, Nianbing; Pan, Fusheng

    2015-01-28

    The following facile approach has been developed to prepare a biomimetic-structural superhydrophobic surface with high stabilities and strong resistances on 2024 Al alloy that are robust to harsh environments. First, a simple hydrothermal treatment in a La(NO3)3 aqueous solution was used to fabricate ginkgo-leaf like nanostructures, resulting in a superhydrophilic surface on 2024 Al. Then a low-surface-energy compound, dodecafluoroheptyl-propyl-trimethoxylsilane (Actyflon-G502), was used to modify the superhydrophilic 2024 Al, changing the surface character from superhydrophilicity to superhydrophobicity. The water contact angle (WCA) of such a superhydrophobic surface reaches up to 160°, demonstrating excellent superhydrophobicity. Moreover, the as-prepared superhydrophobic surface shows high stabilities in air-storage, chemical and thermal environments, and has strong resistances to UV irradiation, corrosion, and abrasion. The WCAs of such a surface almost remain unchanged (160°) after storage in air for 80 days, exposure in 250 °C atmosphere for 24 h, and being exposed under UV irradiation for 24 h, are more than 144° whether in acidic or alkali medium, and are more than 150° after 48 h corrosion and after abrasion under 0.98 kPa for 1000 mm length. The remarkable durability of the as-prepared superhydrophobic surface can be attributed to its stable structure and composition, which are due to the existence of lanthanum (hydr)oxides in surface layer. The robustness of the as-prepared superhydrophobic surface to harsh environments will open their much wider applications. The fabricating approach for such robust superhydrophobic surface can be easily extended to other metals and alloys.

  18. Evaporation kinetics of sessile water droplets on micropillared superhydrophobic surfaces.

    Science.gov (United States)

    Xu, Wei; Leeladhar, Rajesh; Kang, Yong Tae; Choi, Chang-Hwan

    2013-05-21

    Evaporation modes and kinetics of sessile droplets of water on micropillared superhydrophobic surfaces are experimentally investigated. The results show that a constant contact radius (CCR) mode and a constant contact angle (CCA) mode are two dominating evaporation modes during droplet evaporation on the superhydrophobic surfaces. With the decrease in the solid fraction of the superhydrophobic surfaces, the duration of a CCR mode is reduced and that of a CCA mode is increased. Compared to Rowan's kinetic model, which is based on the vapor diffusion across the droplet boundary, the change in a contact angle in a CCR (pinned) mode shows a remarkable deviation, decreasing at a slower rate on the superhydrophobic surfaces with less-solid fractions. In a CCA (receding) mode, the change in a contact radius agrees well with the theoretical expectation, and the receding speed is slower on the superhydrophobic surfaces with lower solid fractions. The discrepancy between experimental results and Rowan's model is attributed to the initial large contact angle of a droplet on superhydrophobic surfaces. The droplet geometry with a large contact angle results in a narrow wedge region of air along the contact boundary, where the liquid-vapor diffusion is significantly restricted. Such an effect becomes minor as the evaporation proceeds with the decrease in a contact angle. In both the CCR and CCA modes, the evaporative mass transfer shows the linear relationship between mass(2/3) and evaporation time. However, the evaporation rate is slower on the superhydrophobic surfaces, which is more significant on the surfaces with lower solid fractions. As a result, the superhydrophobic surfaces slow down the drying process of a sessile droplet on them.

  19. POROSITY CALCULATION OF MIXTURES OF FIBROUS PARTICLES

    Institute of Scientific and Technical Information of China (English)

    Ruping Zou; Aibing Yu

    2003-01-01

    The initial forming of fiber blend to high green density, i.e. the packing of fibrous particles, is important to the reinforcement of composite materials. It is very useful to develop a general predictive method for the optimum selection of particle mixtures for the property control of ceramic or composite products. This paper presents such a mathematical model developed on the basis of the similarity analysis between the spherical and non-spherical particle packings and assesses its applicability to the packing of fibrous particles with discrete and/or continuous length distributions. The results indicate that the model can predict this packing system well and hence provide an effective way to solve various packing problems in the composite materials processing.

  20. Protease-degradable electrospun fibrous hydrogels

    Science.gov (United States)

    Wade, Ryan J.; Bassin, Ethan J.; Rodell, Christopher B.; Burdick, Jason A.

    2015-03-01

    Electrospun nanofibres are promising in biomedical applications to replicate features of the natural extracellular matrix (ECM). However, nearly all electrospun scaffolds are either non-degradable or degrade hydrolytically, whereas natural ECM degrades proteolytically, often through matrix metalloproteinases. Here we synthesize reactive macromers that contain protease-cleavable and fluorescent peptides and are able to form both isotropic hydrogels and electrospun fibrous hydrogels through a photoinitiated polymerization. These biomimetic scaffolds are susceptible to protease-mediated cleavage in vitro in a protease dose-dependent manner and in vivo in a subcutaneous mouse model using transdermal fluorescent imaging to monitor degradation. Importantly, materials containing an alternate and non-protease-cleavable peptide sequence are stable in both in vitro and in vivo settings. To illustrate the specificity in degradation, scaffolds with mixed fibre populations support selective fibre degradation based on individual fibre degradability. Overall, this represents a novel biomimetic approach to generate protease-sensitive fibrous scaffolds for biomedical applications.

  1. Nonlinear mechanics of soft fibrous materials

    CERN Document Server

    Ogden, Raymond

    2015-01-01

    The book presents a state-of-the-art overview of the fundamental theories, established models and ongoing research related to the modeling of these materials. Two approaches are conventionally used to develop constitutive relations for highly deformable fibrous materials. According to the phenomenological approach, a strain energy density function can be defined in terms of strain invariants. The other approach is based on kinetic theories, which treats a fibrous material as a randomly oriented inter-tangled network of long molecular chains bridged by permanent and temporary junctions. At the micro-level, these are associated with chemical crosslinks and active entanglements, respectively. The papers include carefully crafted overviews of the fundamental formulation of the three-dimensional theory from several points of view, and address their equivalences and differences. Also included are solutions to boundary-value problems which are amenable to experimental verification. A further aspect is the elasticity...

  2. Flow condensation on copper-based nanotextured superhydrophobic surfaces.

    Science.gov (United States)

    Torresin, Daniele; Tiwari, Manish K; Del Col, Davide; Poulikakos, Dimos

    2013-01-15

    Superhydrophobic surfaces have shown excellent ability to promote dropwise condensation with high droplet mobility, leading to enhanced surface thermal transport. To date, however, it is unclear how superhydrophobic surfaces would perform under the stringent flow condensation conditions of saturated vapor at high temperature, which can affect superhydrophobicity. Here, we investigate this issue employing "all-copper" superhydrophobic surfaces with controlled nanostructuring for minimal thermal resistance. Flow condensation tests performed with saturated vapor at a high temperature (110 °C) showed the condensing drops penetrate the surface texture (i.e., attain the Wenzel state with lower droplet mobility). At the same time, the vapor shear helped ameliorate the mobility and enhanced the thermal transport. At the high end of the examined vapor velocity range, a heat flux of ~600 kW m(-2) was measured at 10 K subcooling and 18 m s(-1) vapor velocity. This clearly highlights the excellent potential of a nanostructured superhydrophobic surface in flow condensation applications. The surfaces sustained dropwise condensation and vapor shear for five days, following which mechanical degradation caused a transition to filmwise condensation. Overall, our results underscore the need to investigate superhydrophobic surfaces under stringent and realistic flow condensation conditions before drawing conclusions regarding their performance in practically relevant condensation applications.

  3. Delayed Frost Growth on Jumping-Drop Superhydrophobic Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Boreyko, Jonathan B [ORNL; Collier, Pat [ORNL

    2013-01-01

    Self-propelled jumping drops are continuously removed from a condensing superhydrophobic surface to enable a micrometric steady-state drop size. Here, we report that subcooled condensate on a chilled superhydrophobic surface are able to repeatedly jump off the surface before heterogeneous ice nucleation occurs. Frost still forms on the superhydrophobic surface due to ice nucleation at neighboring edge defects, which eventually spreads over the entire surface via an inter-drop frost wave. The growth of this inter-drop frost front is shown to be up to three times slower on the superhydrophobic surface compared to a control hydrophobic surface, due to the jumping-drop effect dynamically minimizing the average drop size and surface coverage of the condensate. A simple scaling model is developed to relate the success and speed of inter-drop ice bridging to the drop size distribution. While other reports of condensation frosting on superhydrophobic surfaces have focused exclusively on liquid-solid ice nucleation for isolated drops, these findings reveal that the growth of frost is an inter-drop phenomenon that is strongly coupled to the wettability and drop size distribution of the surface. A jumping-drop superhydrophobic condenser was found to be superior to a conventional dropwise condenser in two respects: preventing heterogeneous ice nucleation by continuously removing subcooled condensate, and delaying frost growth by minimizing the success of interdrop ice bridge formation.

  4. Delayed frost growth on jumping-drop superhydrophobic surfaces.

    Science.gov (United States)

    Boreyko, Jonathan B; Collier, C Patrick

    2013-02-26

    Self-propelled jumping drops are continuously removed from a condensing superhydrophobic surface to enable a micrometric steady-state drop size. Here, we report that subcooled condensate on a chilled superhydrophobic surface are able to repeatedly jump off the surface before heterogeneous ice nucleation occurs. Frost still forms on the superhydrophobic surface due to ice nucleation at neighboring edge defects, which eventually spreads over the entire surface via an interdrop frost wave. The growth of this interdrop frost front is shown to be up to 3 times slower on the superhydrophobic surface compared to a control hydrophobic surface, due to the jumping-drop effect dynamically minimizing the average drop size and surface coverage of the condensate. A simple scaling model is developed to relate the success and speed of interdrop ice bridging to the drop size distribution. While other reports of condensation frosting on superhydrophobic surfaces have focused exclusively on liquid-solid ice nucleation for isolated drops, these findings reveal that the growth of frost is an interdrop phenomenon that is strongly coupled to the wettability and drop size distribution of the surface. A jumping-drop superhydrophobic condenser minimized frost formation relative to a conventional dropwise condenser in two respects: preventing heterogeneous ice nucleation by continuously removing subcooled condensate, and delaying frost growth by limiting the success of interdrop ice bridge formation.

  5. Recent advances in superhydrophobic nanomaterials and nanoscale systems.

    Science.gov (United States)

    Nagappan, Saravanan; Park, Sung Soo; Ha, Chang-Sik

    2014-02-01

    This review describes the recent advances in the field of superhydrophobic nanomaterials and nanoscale systems. The term superhydrophobic is defined from the surface properties when the surface shows the contact angle (CA) higher than 150 degrees. This could be well known from the lotus effect due to the non-stick and self-cleaning properties of the lotus leaf (LL). We briefly introduced the methods of preparing superhydrophobic surfaces using top-down approaches, bottom-up approaches and a combination of top-down and bottom-up approaches and various ways to prepare superhydrophobic nanomaterials and nanoscale systems using the bio-inspired materials, polymer nanocomposites, metal nanoparticles graphene oxide (GO) and carbon nanotubes (CNTs). We also pointed out the recent applications of the superhydrophobic nanomaterials and nanoscale systems in oil-spill capture and separations, self-cleaning and self-healing systems, bio-medicals, anti-icing and anti-corrosive, electronics, catalysis, textile fabrics and papers etc. The review also highlights the visionary outlook for the future development and use of the superhydrophobic nanomaterials and nanoscale systems for a wide variety of applications.

  6. Superhydrophobic Ag nanostructures on polyaniline membranes with strong SERS enhancement.

    Science.gov (United States)

    Liu, Weiyu; Miao, Peng; Xiong, Lu; Du, Yunchen; Han, Xijiang; Xu, Ping

    2014-11-07

    We demonstrate here a facile fabrication of n-dodecyl mercaptan-modified superhydrophobic Ag nanostructures on polyaniline membranes for molecular detection based on SERS technique, which combines the superhydrophobic condensation effect and the high enhancement factor. It is calculated that the as-fabricated superhydrophobic substrate can exhibit a 21-fold stronger molecular condensation, and thus further amplifies the SERS signal to achieve more sensitive detection. The detection limit of the target molecule, methylene blue (MB), on this superhydrophobic substrate can be 1 order of magnitude higher than that on the hydrophilic substrate. With high reproducibility, the feasibility of using this SERS-active superhydrophobic substrate for quantitative molecular detection is explored. A partial least squares (PLS) model was established for the quantification of MB by SERS, with correlation coefficient R(2) = 95.1% and root-mean-squared error of prediction (RMSEP) = 0.226. We believe this superhydrophobic SERS substrate can be widely used in trace analysis due to its facile fabrication, high signal reproducibility and promising SERS performance.

  7. Interaction between Air Bubbles and Superhydrophobic Surfaces in Aqueous Solutions.

    Science.gov (United States)

    Shi, Chen; Cui, Xin; Zhang, Xurui; Tchoukov, Plamen; Liu, Qingxia; Encinas, Noemi; Paven, Maxime; Geyer, Florian; Vollmer, Doris; Xu, Zhenghe; Butt, Hans-Jürgen; Zeng, Hongbo

    2015-07-07

    Superhydrophobic surfaces are usually characterized by a high apparent contact angle of water drops in air. Here we analyze the inverse situation: Rather than focusing on water repellency in air, we measure the attractive interaction of air bubbles and superhydrophobic surfaces in water. Forces were measured between microbubbles with radii R of 40-90 μm attached to an atomic force microscope cantilever and submerged superhydrophobic surfaces. In addition, forces between macroscopic bubbles (R = 1.2 mm) at the end of capillaries and superhydrophobic surfaces were measured. As superhydrophobic surfaces we applied soot-templated surfaces, nanofilament surfaces, micropillar arrays with flat top faces, and decorated micropillars. Depending on the specific structure of the superhydrophobic surfaces and the presence and amount of entrapped air, different interactions were observed. Soot-templated surfaces in the Cassie state showed superaerophilic behavior: Once the electrostatic double-layer force and a hydrodynamic repulsion were overcome, bubbles jumped onto the surface and fully merged with the entrapped air. On nanofilaments and micropillar arrays we observed in addition the formation of sessile bubbles with finite contact angles below 90° or the attachment of bubbles, which retained their spherical shape.

  8. Effect of polymer concentration on the morphology and mechanical characteristics of electrospun cellulose acetate and poly (vinyl chloride nanofiber mats

    Directory of Open Access Journals (Sweden)

    Bethwel Tarus

    2016-09-01

    Full Text Available Cellulose Acetate (CA and Poly (Vinyl Chloride (PVC nanofiber mats were electrospun into nanofibers. The morphology and mechanical properties of nanofiber mats were evaluated versus different solution concentrations. Solutions were prepared in mixed solvent systems of 2:1 (w/w Acetone/N,N-Dimethylacetamide (DMAc and 3:2 (w/w Acetone/N,N-Dimethylformamide (DMF for CA and 1:1 (w/w Tetrahydrofuran/DMF for PVC. Scanning electron microscopy (SEM images revealed that a beaded fibrous structure could be electrospun beginning at 10% CA in both Acetone/DMAc and Acetone/DMF solvent systems. The experimental results showed that smooth fibers were achievable at 14% CA in Acetone/DMAc and at 16% CA in Acetone/DMF solvent systems. For PVC, beaded fibers were formed at 12% PVC and smooth fibers were formed beginning at 14% PVC. Tensile strength tests showed that mechanical properties of the nonaligned nanofiber mats were influenced by solution concentration. With increasing solution concentration, the tensile strengths, break strains and initial moduli of the CA nanofiber mats increased. The effect of solution concentration on the tensile strengths of nanofiber mats was quite significant while it did not have any considerable effect on the tensile properties of the cast films.

  9. First description of Phanerozoic radiaxial fibrous dolomite

    Science.gov (United States)

    Richter, D. K.; Heinrich, F.; Geske, A.; Neuser, R. D.; Gies, H.; Immenhauser, A.

    2014-05-01

    The petrographic analysis and crystallographic analysis of concretionary carbonate cements ("coal balls") from Carboniferous paralic swamp deposits reveal the presence of (length fast) radiaxial fibrous dolomite (RFD), a fabric not previously reported from the Phanerozoic. This finding is of significance as earlier reports of Phanerozoic radiaxial fibrous carbonates are exclusively of calcite mineralogy. Dolomite concretions described here formed beneath marine transgressive intervals within palustrine coal seams. This is of significance as seawater was arguably the main source of Mg2 + ions for dolomite formation. Here, data from optical microscopy, cathodoluminescence, electron backscattered diffraction, X-ray diffraction and geochemical analyses are presented to characterize three paragenetic dolomite phases and one calcite phase in these concretions. The main focus is on the earliest diagenetic, non-stoichiometric (degree of order: 0.41-0.46) phase I, characterized by botryoidal dolomite constructed of fibres up to 110 μm wide with a systematic undulatory extinction and converging crystal axes. Petrographic and crystallographic evidence clearly qualifies phase I dolomite as radiaxial fibrous. Conversely, fascicular optical fabrics were not found. Carbon-isotope ratios (δ13C) are depleted (between - 11.8 and - 22.1‰) as expected for carbonate precipitation from marine pore-fluids in organic-matter-rich, paralic sediment. Oxygen isotope (δ18O) ratios range between - 1.3 and - 6.0‰. The earliest diagenetic nature of these cements is documented by the presence of ubiquitous, non-compacted fossil plant remains encased in phase I dolomite as well as by the complex zoned luminescence patterns in the crystals and is supported by crystallographic and thermodynamic considerations. It is argued that organic matter, and specifically carboxyl groups, reduced thermodynamic barriers for dolomite formation and facilitated Mg/CaCO3 precipitation. The data shown here

  10. High surface area fibrous silica nanoparticles

    KAUST Repository

    Polshettiwar, Vivek

    2014-11-11

    Disclosed are high surface area nanoparticles that have a fibrous morphology. The nanoparticles have a plurality of fibers, wherein each fiber is in contact with one other fiber and each fiber has a length of between about 1 nm and about 5000 nm. Also disclosed are applications of the nanoparticles of the present invention, and methods of fabrication of the nanoparticles of the present invention.

  11. Monostotic fibrous dysplasia with Raynaud's phenomenon.

    Science.gov (United States)

    Kumar, K V S Hari; Aravinda, K; Narayanan, K

    2015-01-01

    Fibrous dysplasia (FD) is a benign bone disorder characterized by alteration in bone morphology. Monostotic FD is the commonest variant and affects the craniofacial bones. Raynaud's phenomenon is recurrent vasospasm of the fingers and toes due to cold exposure. The disease is usually idiopathic or secondary to connective tissue disorders. Raynaud's phenomenon is not described previously with FD. We recently encountered two interesting patients of craniofacial monostotic FD with Raynaud's phenomenon and report the same in this report.

  12. Malignant fibrous histiocytoma of the abdominal wall

    OpenAIRE

    Arif Aslaner; Burhan Mayir; Tuğrul Çakır; Umut Rıza Gündüz; Nurullah Bülbüller

    2015-01-01

    Malignant fibrous histiocytoma (MFH) or undifferentiated pleomorphic sarcoma is a type of malignt neoplasm that arises from any soft tissue and bone involving extremities, abdomen and retroperitoneum. MFH of the external oblique abdominis muscle is rare. Surgical resection of the mass is the treatment of choice depending on the stage of the disease and the invasion depth of the tumor. Radiotherapy, chemotherapy and immunotherapy are the other treatment methods. We present a case of a 71-year ...

  13. Poly(3-hydroxybutyrate)/caffeic acid electrospun fibrous materials coated with polyelectrolyte complex and their antibacterial activity and in vitro antitumor effect against HeLa cells

    Energy Technology Data Exchange (ETDEWEB)

    Ignatova, Milena G. [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St, Bl. 103A, BG-1113 Sofia (Bulgaria); Manolova, Nevena E., E-mail: manolova@polymer.bas.bg [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St, Bl. 103A, BG-1113 Sofia (Bulgaria); Rashkov, Iliya B. [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St, Bl. 103A, BG-1113 Sofia (Bulgaria); Markova, Nadya D. [Institute of Microbiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Bl. 26, BG-1113 Sofia (Bulgaria); Toshkova, Reneta A.; Georgieva, Ani K.; Nikolova, Elena B. [Institute of Experimental Morphology, Pathology and Anthropology with Museum, Bulgarian Academy of Sciences, Acad. G. Bonchev St, bl. 25, BG-1113 Sofia (Bulgaria)

    2016-08-01

    The purpose of this work was to investigate the possibility for the preparation of new poly(3-hydroxybutyrate) (PHB)/poly(ethylene glycol) (PEG)-based fibrous materials containing natural phenolic compound caffeic acid (CA) of diverse architectures, as well as to study the impact of the fiber composition on the in vitro CA release profile and on the biological properties of the fibrous materials. The application of the one-pot electrospinning enabled the fabrication of nanofibrous materials from PHB and PEG loaded with the CA. Materials with targeted design were obtained by coating with polyelectrolyte complex of alginate (Alg) and N,N,N-trimethylchitosan (TMCh). Three different processing paths were used to obtain coated mats: (i) with CA incorporated in the PHB/PEG core; (ii) with CA embedded in the Alg layer; and (iii) with CA included in the TMCh layer. The in vitro release of CA was modulated by controlling the composition and the architecture of the nanofibrous mats. The performed microbiological screening and MTT cell viability studies revealed that in contrast to the bare mats, the CA-containing nanofibrous materials were effective in suppressing the growth of the Gram-positive bacteria Staphylococcus aureus and the Gram-negative bacteria Escherichia coli and displayed good cytotoxicity against human cervical HeLa tumor cells. In addition, the proliferation of murine spleen lymphocytes and peritoneal macrophages was increased by the prepared CA-containing nanofibrous materials. The obtained materials are promising for antibacterial wound dressing applications as well as for application in local treatment of cervical tumors. - Highlights: • New caffeic acid-loaded materials from PHB and PEG were prepared by electrospinning. • Different design is achieved by coating and formation of polyelectrolyte complexes. • The control on the architecture of the mats enables modulating caffeic acid release. • The caffeic acid-loaded mats suppress the growth of

  14. Superhydrophobic modification fails to improve the performance of small diameter expanded polytetrafluoroethylene vascular grafts

    NARCIS (Netherlands)

    Toes, GJ; van Muiswinkel, KW; van Oeveren, W; Suurmeijer, AJH; Timens, W; Stokroos, [No Value; van den Dungen, JJAM

    To determine whether superhydrophobic modification of small diameter expanded polytetrafluoroethylene (ePTFE) vascular grafts improves the performance of these grafts, we assessed neointima formation and platelet deposition in standard and superhydrophobic modified ePTFE grafts. Standard and

  15. Flat laminated microbial mat communities

    Science.gov (United States)

    Franks, Jonathan; Stolz, John F.

    2009-10-01

    Flat laminated microbial mats are complex microbial ecosystems that inhabit a wide range of environments (e.g., caves, iron springs, thermal springs and pools, salt marshes, hypersaline ponds and lagoons, methane and petroleum seeps, sea mounts, deep sea vents, arctic dry valleys). Their community structure is defined by physical (e.g., light quantity and quality, temperature, density and pressure) and chemical (e.g., oxygen, oxidation/reduction potential, salinity, pH, available electron acceptors and donors, chemical species) parameters as well as species interactions. The main primary producers may be photoautotrophs (e.g., cyanobacteria, purple phototrophs, green phototrophs) or chemolithoautophs (e.g., colorless sulfur oxidizing bacteria). Anaerobic phototrophy may predominate in organic rich environments that support high rates of respiration. These communities are dynamic systems exhibiting both spatial and temporal heterogeneity. They are characterized by steep gradients with microenvironments on the submillimeter scale. Diel oscillations in the physical-chemical profile (e.g., oxygen, hydrogen sulfide, pH) and species distribution are typical for phototroph-dominated communities. Flat laminated microbial mats are often sites of robust biogeochemical cycling. In addition to well-established modes of metabolism for phototrophy (oxygenic and non-oxygenic), respiration (both aerobic and anaerobic), and fermentation, novel energetic pathways have been discovered (e.g., nitrate reduction couple to the oxidation of ammonia, sulfur, or arsenite). The application of culture-independent techniques (e.g., 16S rRNA clonal libraries, metagenomics), continue to expand our understanding of species composition and metabolic functions of these complex ecosystems.

  16. A Case of Extensive polyostotic fibrous dysplasia

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byung Do [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Wonkwang University, Iksan (Korea, Republic of); Hwang, Eui Hwan; Lee, Sang Rae [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Kyunghee University, Seoul (Korea, Republic of)

    2000-06-15

    Fibrous dysplasia is a benign disorder of bone consisting of intramedullary proliferation of fibrous tissue and irregularly distributed, poorly developed bone. The disease manifests itself in the monostotic form in which only one bone is involved and the polyostotic form in which multiple bones at different sites are affected. We reported a extensive case of polyostotic fibrous dysplasia with involvement of craniofacial bones, mandible, ribs, extremities. A 18-year-old man showed remarkable right facial swelling who had been treated on right femur 3 years ago with a bone graft for pathologic fracture and he recognized facial swelling 5 years ago. Extraoral radiograms and computed tomogram showed diffuse sclerosis with a ground glass appearance of the most calvarial bones, facial bones. The right mandibular lesion showed very expansible lesion with mottled appearance. Bone scans showed multifocal increased uptakes in craniofacial bones, right mandible, bilaterally in ribs, humerus, femur, tibia and characteristic various deformity of right femur (shepherd's crook deformity). This case showed exceptionally bilateral, extensive nature of bone lesion and didn't show any features of skin pigmentation and endocrine disturbances.

  17. Toxicity and Carcinogenicity Mechanisms of Fibrous Antigorite

    Directory of Open Access Journals (Sweden)

    Michael Balazy

    2007-03-01

    Full Text Available We studied the effects of fibrous antigorite on mesothelial MeT-5A and monocyte-macrophage J774 cell lines to further understand cellular mechanisms induced by asbestos fibers leading to lung damage and cancer. Antigorite is a mineral with asbestiform properties, which tends to associate with chrysotile or tremolite, and frequently occurs as the predominant mineral in the veins of several serpentinite rocks found abundantly in the Western Alps. Particles containing antigorite are more abundant in the breathing air of this region than those typically found in urban ambient air. Exposure of MeT-5A and J774 cells to fibrous antigorite at concentrations of 5-100 μg/ml for 72 hr induced dose-dependent cytotoxicity. Antigorite also stimulated the ROS production, induced the generation of nitrite and PGE2. MeT-5A cells were more sensitive to antigorite than J774 cells. The results of this study revealed that the fibrous antigorite stimulates cyclooxygenase and formation of hydroxyl and nitric oxide radicals. These changes represent early cellular responses to antigorite fibers, which lead to a host of pathological and neoplastic conditions because free radicals and PGE2 play important roles as mediators of tumor pathogenesis. Understanding the mechanisms of the cellular responses to antigorite and other asbestos particles should be helpful in designing rational prevention and treatment approaches.

  18. Fibrous zinc anodes for high power batteries

    Science.gov (United States)

    Zhang, X. Gregory

    This paper introduces newly developed solid zinc anodes using fibrous material for high power applications in alkaline and large size zinc-air battery systems. The improved performance of the anodes in these two battery systems is demonstrated. The possibilities for control of electrode porosity and for anode/battery design using fibrous materials are discussed in light of experimental data. Because of its mechanical integrity and connectivity, the fibrous solid anode has good electrical conductivity, mechanical stability, and design flexibility for controlling mass distribution, porosity and effective surface area. Experimental data indicated that alkaline cells made of such anodes can have a larger capacity at high discharging currents than commercially available cells. It showed even greater improvement over commercial cells with a non-conventional cell design. Large capacity anodes for a zinc-air battery have also been made and have shown excellent material utilization at various discharge rates. The zinc-air battery was used to power an electric bicycle and demonstrated good results.

  19. The MAT1-1:MAT1-2 ratio of Sporothrix globosa isolates in Japan.

    Science.gov (United States)

    Kano, Rui; Tsui, Clement K-M; Hamelin, Richard C; Anzawa, Kazushi; Mochizuki, Takashi; Nishimoto, Katsutaro; Hiruma, Masataro; Kamata, Hiroshi; Hasegawa, Atsuhiko

    2015-02-01

    In order to understand the reproductive biology of pathogenic species in the Sporothrix schenckii complex, we characterized the partial mating type (MAT1-1) loci of Sporothrix schenckii, as well as the S. globosa MAT1-1-1 gene, which encoded 262 amino acid sequences. The data confirmed that the MAT1-1 locus of S. globosa was divergent from the MAT1-2 locus of the opposite mating type, suggesting that the fungus is heterothallic. To determine the mating type ratio of 20 isolates from Japanese patients, we analyzed the MAT loci by specific PCR amplification of MAT1-1-1 and MAT1-2-1 genes. The MAT1-1-1 was detected in 5 isolates but not in the other 15 isolates with the presence of MAT1-2-1. The MAT1-1:1-2 ratio of S. globosa isolates in Japan was estimated to be 1:3. Phylogenetic analysis indicated that the sequences of the MAT1-1-1 were identical among S. globosa isolates but different from S. schenckii and Ophiostoma montium.

  20. Process of making titanium carbide (TiC) nano-fibrous felts

    Energy Technology Data Exchange (ETDEWEB)

    Fong, Hao; Zhang, Lifeng; Zhao, Yong; Zhu, Zhengtao

    2015-01-13

    A method of synthesizing mechanically resilient titanium carbide (TiC) nanofibrous felts comprising continuous nanofibers or nano-ribbons with TiC crystallites embedded in carbon matrix, comprising: (a) electrospinning a spin dope for making precursor nanofibers with diameters less than 0.5 J.Lm; (b) overlaying the nanofibers to produce a nanofibrous mat (felt); and then (c) heating the nano-felts first at a low temperature, and then at a high temperature for making electrospun continuous nanofibers or nano-ribbons with TiC crystallites embedded in carbon matrix; and (d) chlorinating the above electrospun nano-felts at an elevated temperature to remove titanium for producing carbide derived carbon (CDC) nano-fibrous felt with high specific surface areas.

  1. An atomistic-continuum hybrid simulation of fluid flows over superhydrophobic surfaces

    OpenAIRE

    Li, Qiang; He, Guo-Wei

    2009-01-01

    Recent experiments have found that slip length could be as large as on the order of 1 μm for fluid flows over superhydrophobic surfaces. Superhydrophobic surfaces can be achieved by patterning roughness on hydrophobic surfaces. In the present paper, an atomistic-continuum hybrid approach is developed to simulate the Couette flows over superhydrophobic surfaces, in which a molecular dynamics simulation is used in a small region near the superhydrophobic surface where the continuum assumption i...

  2. Triggered Drug Release from Superhydrophobic Meshes using High-Intensity Focused Ultrasound

    OpenAIRE

    Yohe, Stefan T.; Kopechek, Jonathan A.; Porter, Tyrone M; Colson, Yolonda L.; Grinstaff, Mark W.

    2013-01-01

    Application of high-intensity focused ultrasound to drug-loaded superhydrophobic meshes affords triggered drug release by displacing an entrapped air layer. The air layer within the superhydrophobic meshes is characterized using direct visualization and B-mode imaging. Drug-loaded superhydrophobic meshes are cytotoxic in an in vitro assay after ultrasound treatment.

  3. Comparison of Three Methods for Generating Superhydrophobic, Superoleophobic Nylon Nonwoven Surfaces (Postprint)

    Science.gov (United States)

    2011-04-01

    AFRL-RX-TY-TP-2010-0076 COMPARISON OF THREE METHODS FOR GENERATING SUPERHYDROPHOBIC, SUPEROLEOPHOBIC NYLON NONWOVEN SURFACES Rahul Saraf...Generating Superhydrophobic, Superoleophobic Nylon Nonwoven Surfaces (POSTPRINT) FA8650-07-1-5916 0602102F GOVT L0 QL102006 ^Saraf, Rahul,; ^Lee, Hoon...three different techniques to achieve superhydrophobicity and superoleophobicity using hydroentangled nylon nonwoven fabric: pulsed plasma polymerization

  4. Article coated with flash bonded superhydrophobic particles

    Science.gov (United States)

    Simpson, John T [Clinton, TN; Blue, Craig A [Knoxville, TN; Kiggans, Jr., James O [Oak Ridge, TN

    2010-07-13

    A method of making article having a superhydrophobic surface includes: providing a solid body defining at least one surface; applying to the surface a plurality of diatomaceous earth particles and/or particles characterized by particle sizes ranging from at least 100 nm to about 10 .mu.m, the particles being further characterized by a plurality of nanopores, wherein at least some of the nanopores provide flow through porosity, the particles being further characterized by a plurality of spaced apart nanostructured features that include a contiguous, protrusive material; flash bonding the particles to the surface so that the particles are adherently bonded to the surface; and applying a hydrophobic coating layer to the surface and the particles so that the hydrophobic coating layer conforms to the nanostructured features.

  5. Superhydrophobic surfaces in turbulent channel flow

    Science.gov (United States)

    Li, Yixuan; Alame, Karim; Mahesh, Krishnan

    2016-11-01

    The drag reduction effect of superhydrophobic surfaces in turbulent channel flow is studied using direct numerical simulation. The volume of fluid (VOF) methodology is used to resolve the dynamics of the interface. Laminar flow simulations show good agreement with experiment, and illustrate the relative importance of geometry and interface boundary condition. An analytical solution for the multi-phase problem is obtained that shows good agreement with simulation. Turbulent simulations over a longitudinally grooved surface show drag reduction even in the fully wetted regime. The statistics show that geometry alone can cause an apparent slip to the external flow. Instantaneous plots indicate that the grooves prevent the penetration of near wall vorticity, yielding overall drag reduction. Results for spectra, wall pressure fluctuations and correlations will be presented. Unsteady effects on the air-vapor interface will be discussed. Results for random roughness surfaces will be presented. Supported by Office of Naval Research.

  6. Effective slippage on superhydrophobic trapezoidal grooves

    CERN Document Server

    Zhou, Jiajia; Schmid, Friederike; Vinogradova, Olga I

    2013-01-01

    We study the effective slippage on superhydrophobic grooves with trapezoidal cross-sections of various geometries (including the limiting cases of triangles and rectangular stripes), by using two complementary approaches. First, dissipative particle dynamics (DPD) simulations of a flow past such surfaces have been performed to validate an expression [E.S.Asmolov and O.I.Vinogradova, J. Fluid Mech. \\textbf{706}, 108 (2012)] that relates the eigenvalues of the effective slip-length tensor for one-dimensional textures. Second, we propose theoretical estimates for the effective slip length and calculate it numerically by solving the Stokes equation based on a collocation method. The comparison between the two approaches shows that they are in excellent agreement. Our results demonstrate that the effective slippage depends strongly on the area-averaged slip, the amplitude of the roughness, and on the fraction of solid in contact with the liquid. To interpret these results, we analyze flow singularities near slippi...

  7. Synthesis of Superhydrophobic Nanocomposite Coatings Using Electrodeposition

    Science.gov (United States)

    Iacovetta, Daniel John

    The focus of the current research is to produce a metal matrix composite material that possesses a superhydrophobic surface using electrodeposition. The objective is to create a multifunctional coating that is able to provide high strength as well as high water repellency using nanocrystalline nickel and polytetrafluoroethylene (PTFE) particles. The co-deposition process was first studied. It was determined that the amount of PTFE co-deposited is highly dependent on the concentration of PTFE particles in the electroplating bath. The wetting angle of the surface greatly increased when the PTFE content increases. Next the electroplating procedure of pure nickel is altered to produce a nanocrystalline material, resulting in a large increase in the hardness of the nickel coatings. The two techniques are combined to produce a nanocrystalline Nickel-PTFE composite. Under optimum conditions, the composite coating displayed a highly water repellent surface and improved mechanical properties.

  8. Sessile droplet evaporation on superheated superhydrophobic surfaces

    CERN Document Server

    Hays, Robb C; Maynes, Daniel; Webb, Brent W

    2013-01-01

    This fluid dynamics video depicts the evaporation of sessile water droplets placed on heated superhydrophobic (SH) surfaces of varying cavity fraction, F_c, and surface temperature, T_s, above the saturation temperature, T_sat. Images were captured at 10,000 FPS and are played back at 30 FPS in this video. Teflon-coated silicon surfaces of F_c = 0, 0.5, 0.8, and 0.95 were used for these experiments. T_s ranging from 110{\\deg}C to 210{\\deg}C were studied. The video clips show how the boiling behavior of sessile droplets is altered with changes in surface microstructure. Quantitative results from heat transfer rate experiments conducted by the authors are briefly discussed near the end of the video.

  9. Superhydrophobic lignocellulosic wood fiber/mineral networks.

    Science.gov (United States)

    Mirvakili, Mehr Negar; Hatzikiriakos, Savvas G; Englezos, Peter

    2013-09-25

    Lignocellulosic wood fibers and mineral fillers (calcium carbonate, talc, or clay) were used to prepare paper samples (handsheets), which were then subjected to a fluorocarbon plasma treatment. The plasma treatment was performed in two steps: first using oxygen plasma to create nanoscale roughness on the surface of the handsheet, and second fluorocarbon deposition plasma to add a layer of low surface energy material. The wetting behavior of the resulting fiber/mineral network (handsheet) was determined. It was found the samples that were subjected to oxygen plasma etching prior to fluorocarbon deposition exhibit superhydrophobicity with low contact angle hysteresis. On the other hand, those that were only treated by fluorocarbon plasma resulted in "sticky" hydrophobicity behavior. Moreover, as the mineral content in the handsheet increases, the hydrophobicity after plasma treatment decreases. Finally, it was found that although the plasma-treated handsheets show excellent water repellency they are not good water vapor barriers.

  10. Obtaining superhydrophobicity using commercial razor blades

    CERN Document Server

    Yamamoto, Ken; Ogata, Satoshi

    2015-01-01

    Because the superhydrophobic characteristic appears by forming a composite surface consisting of solid and air underneath the droplets, a large number of rough surfaces that can trap air have been fabricated. Recently, the air trapping on materials whose equilibrium contact angles are less than 90 degrees was achieved by fabricating proper structures that lead energetic stability at the condition. Whereas these methods were proposed under the assumption of the static and equilibrium conditions, we take a dynamic and non-equilibrium approach in this study through droplet deposition and droplet impact experiments. By employing test surfaces that consist of commercially available stainless steel razor blades, we show the pinning effect brings the apparent water contact angle of approximately 160 degrees on a "hydrophilic" substrate. We call this state the "non-equilibrium Cassie state" and give theoretical explanations. Furthermore, the dynamic characteristics of the droplet impact on these surfaces are discusse...

  11. Microstructuring of electrospun mats employing femtosecond laser

    Directory of Open Access Journals (Sweden)

    Erika Adomavičiūtė

    2015-03-01

    Full Text Available Electrospun mats from nano/micro-fibers with control porosity and pore shape may be ideal candidate for tissue engineering scaffolds. In this study three type of poly(vinyl alcohol (PVA mats of 48-65 µm thickness with different nano/micro-fibers diameters mostly of 100-200 nm were deposited by electrospinning process. Controlled density porosity in the electrospun mats was introduced by Yb:KGW femtosecond laser micromachining system. The influence of electrospun mat micro structure, the distance between the adjacent laser ablation points, the number of femtosecond laser pulses on quality and structure of laser irradiated holes were investigated. It was demonstrated that the quality of irradiated holes depend on structure of electrospun mats (diameter of nano/micro-fibers, thickness of mats and femtosecond laser processing parameters. Varying the distance between points and number of applied femtosecond laser pulses it is possible to fabricate electrospun mats with pores of 22-36 μm diameter.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.10249

  12. Electrospun superhydrophobic membranes with unique structures for membrane distillation.

    Science.gov (United States)

    Liao, Yuan; Loh, Chun-Heng; Wang, Rong; Fane, Anthony G

    2014-09-24

    With modest temperature demand, low operating pressure, and high solute rejection, membrane distillation (MD) is an attractive option for desalination, waste treatment, and food and pharmaceutical processing. However, large-scale practical applications of MD are still hindered by the absence of effective membranes with high hydrophobicity, high porosity, and adequate mechanical strength, which are important properties for MD permeation fluxes, stable long-term performance, and effective packing in modules without damage. This study describes novel design strategies for highly robust superhydrophobic dual-layer membranes for MD via electrospinning. One of the newly developed membranes comprises a durable and ultrathin 3-dimensional (3D) superhydrophobic skin and porous nanofibrous support whereas another was fabricated by electrospinning 3D superhydrophobic layers on a nonwoven support. These membranes exhibit superhydrophobicity toward distilled water, salty water, oil-in-water emulsion, and beverages, which enables them to be used not only for desalination but also for other processes. The superhydrophobic dual-layer membrane #3S-N with nanofibrous support has a competitive permeation flux of 24.6 ± 1.2 kg m(-2) h(-1) in MD (feed and permeate temperate were set as 333 and 293 K, respectively) due to the higher porosity of the nanofibrous scaffold. Meanwhile, the membranes with the nonwoven support exhibit greater mechanical strength due to this support combined with better long-term performance because of the thicker 3D superhydrophobic layers. The morphology, pore size, porosity, mechanical properties, and liquid enter pressure of water of these superhydrophobic composite membranes with two different structures are reported and compared with commercial polyvinylidene fluoride membranes.

  13. Biocidal Activity of Plasma Modified Electrospun Polysulfone Mats Functionalized with Polyethyleneimine-Capped Silver Nanoparticles

    KAUST Repository

    Schiffman, Jessica D.

    2011-11-01

    The incorporation of silver nanoparticles (AgNPs) into polymeric nanofibers has attracted a great deal of attention due to the strong antimicrobial activity that the resulting fibers exhibit. However, bactericidal efficacy of AgNP-coated electrospun fibrous mats has not yet been demonstrated. In this study, polysulfone (PSf) fibers were electrospun and surface-modified using an oxygen plasma treatment, which allowed for facile irreversible deposition of cationically charged polyethyleneimine (PEI)-AgNPs via electrostatic interactions. The PSf-AgNP mats were characterized for relative silver concentration as a function of plasma treatment time using ICP-MS and changes in contact angle. Plasma treatment of 60 s was the shortest time required for maximum loss of bacteria (Escherichia coli) viability. Time-dependent bacterial cytotoxicity studies indicate that the optimized PSf-AgNP mats exhibit a high level of inactivation against both Gram negative bacteria, Escherichia coli, and Gram positive bacteria, Bacillus anthracis and Staphylococcus aureus. © 2011 American Chemical Society.

  14. Malignant transformation of fibrous dysplasia into chondroblastic osteosarcoma

    Energy Technology Data Exchange (ETDEWEB)

    Kaushik, Shaifali [Department of Radiology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA (United States); Department of Radiology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA (United States); Smoker, Wendy R.K. [Department of Radiology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA (United States); Frable, William J. [Department of Pathology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA (United States)

    2002-02-01

    A case of malignant transformation of polyostotic fibrous dysplasia into maxillary chondroblastic osteosarcoma is presented. The clinical, radiographic, CT, MR imaging features and pathological findings of polyostotic fibrous dysplasia and its malignant transformation are described. Malignant transformation of fibrous dysplasia is rare and has not previously been described in the English literature in this location in McCune-Albright syndrome and in the absence of radiation treatment. (orig.)

  15. Fibrous dysplasia. Clinical review and therapeutic management.

    Science.gov (United States)

    Florez, Helena; Peris, Pilar; Guañabens, Núria

    2016-12-16

    Fibrous dysplasia is a skeletal disorder that is associated with a wide spectrum of clinical manifestations, including localized asymptomatic forms and extensive severe forms with severe bone deformities and endocrinological alterations, depending on age, location, extent and associated processes. Although the treatment of choice is based on bisphosphonates, the therapeutic efficacy of these agents in the control of disease activity remains uncertain. This article reviews the current data available on the treatment of this disease as well as the preliminary data on new therapeutic approaches. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  16. Compressibility of air in fibrous materials

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    1996-01-01

    The dynamic compressibility of air in fibrous materials has been computed for two assumed configurations of fibers which are close to the geometry of real fiber materials. Models with parallel cylinders placed in a regular square lattice and placed randomly are treated. For these models...... the compressibility is computed approximately from the diameter and mean distances between cylinders. This requires calculation of the air temperature, which is calculated for cylinders in a regular lattive by the Wigner-Seitz cell approximation. In the case of random placement, the calculation is done by a summation...

  17. [Solitary naso-sinusal fibrous tumor].

    Science.gov (United States)

    Martínez, V; Jiménez, M L; Cuatrecasas, M; Jürgens, A; de Amesti, C; Orus, C; Fabra, J M

    1995-01-01

    Here we present two clinical cases of solitary naso-sinusal fibrous tumour. This tumour has a mesenchymal origin and has an evident pleural location, with well defined immunohistochemical and ultrastructural characteristics. The clinical manifestation is an apparent benign tumour with an inclination to local aggressiveness. The most effective treatment seems to be surgical removal, but given the low number of cases mentioned (there are only eight cases reported in international literature), and the tendency to eventual recurrence, called for cobalt therapy after surgery. The evolution of clinical cases is irregular.

  18. Fabrication of highly aligned fibrous scaffolds for tissue regeneration by centrifugal spinning technology.

    Science.gov (United States)

    Loordhuswamy, Amalorpava Mary; Krishnaswamy, Venkat Raghavan; Korrapati, Purna Sai; Thinakaran, Senthilram; Rengaswami, Giri Dev Venkateshwarapuram

    2014-09-01

    Centrifugal spinning (C-Spin) is an emerging technology which uses centrifugal force to produce ultrafine fibers. Being a voltage free technique it can overcome the limitations of electrospinning. Owing to the unique characteristic features such as high surface area to volume ratio, porosity, mechanical strength and fiber alignment, centrifugal spun (C-spun) fibrous mat has a wide range of scope in various biomedical applications. Higher degree of fiber alignment can be effortlessly achieved by the C-Spin process. In order to prove the versatility of C-Spin system with respect to fiber alignment, Polycaprolactone (PCL) and gelatin were spun taking them as model polymers. The morphological analysis revealed that highly aligned ultrafine fibers with smooth surface are achieved by C-Spinning. Hydrophilicity, porosity and mechanical property results confirm that the C-spun mat is more suitable for tissue engineering applications. In vitro and in vivo experiments proved that the scaffolds are biocompatible and can be efficiently used as a wound dressing material.

  19. Stability of plasma treated superhydrophobic surfaces under different ambient conditions.

    Science.gov (United States)

    Chen, Faze; Liu, Jiyu; Cui, Yao; Huang, Shuai; Song, Jinlong; Sun, Jing; Xu, Wenji; Liu, Xin

    2016-05-15

    Plasma hydrophilizing of superhydrophobic substrates has become an important area of research, for example, superhydrophobic-(super)hydrophilic patterned surfaces have significant practical applications such as lab-on-chip systems, cell adhesion, and control of liquid transport. However, the stability of plasma-induced hydrophilicity is always considered as a key issue since the wettability tends to revert back to the untreated state (i.e. aging behavior). This paper focuses on the stability of plasma treated superhydrophobic surface under different ambient conditions (e.g. temperature and relative humidity). Water contact angle measurement and X-ray photoelectron spectroscopy are used to monitor the aging process. Results show that low temperature and low relative humidity are favorable to retard the aging process and that pre-storage at low temperature (-10°C) disables the treated surface to recover superhydrophobicity. When the aging is performed in water, a long-lasting hydropholicity is obtained. As the stability of plasma-induced hydrophilcity over a desired period of time is a very important issue, this work will contribute to the optimization of storage conditions of plasma treated superhydrophobic surfaces.

  20. Water slip flow in superhydrophobic microtubes within laminar flow region

    Institute of Scientific and Technical Information of China (English)

    Zhijia Yu; Xinghua Liu; Guozhu Kuang

    2015-01-01

    The fabrication of superhydrophobic surfaces and the studies on water flow characteristics therein are of great significance to many industrial areas as wel as to science and technology development. Experiments were car-ried out to investigate slip characteristics of water flowing in circular superhydrophobic microtubes within lam-inar flow region. The superhydrophobic microtubes of stainless steel were fabricated with chemical etching–fluorination treatment. An experimental setup was designed to measure the pressure drop as function of water flow rate. For comparison, superhydrophilic tubes were also tested. Poiseuille number Po was found to be smaller for the superhydrophobic microtubes than that for superhydrophilic ones. The pressure drop reduc-tion ranges from 8%to 31%. It decreases with increasing Reynolds number when Re b 900, owing to the transition from Cassie state to Wenzel state. However, it is almost unchanged with further increasing Re after Re N 900. The slip length in superhydrophobic microtubes also exhibits a Reynolds number dependence similarly to the pressure drop reduction. The relation between slip length and Darcy friction factor is theoretically analyzed with consideration of surface roughness effect, which was testified with the experimental results.

  1. Preparation and characterization of NaOH treated micro-fibrous polyethylene terephthalate nonwovens for biomedical application.

    Science.gov (United States)

    Hadjizadeh, Afra; Ajji, Abdellah; Bureau, Martin N

    2010-11-01

    Recently, micro-fibrous polyethylene terephthalate nonwovens have been investigated and applied in many biotechnological and biomedical applications. NaOH treatment has been used as a simple and cost effective method to alter surface properties, in order to overcome their surface inertness. However, the effects of this treatment on the matrices mechanical and physical properties; particularly, those composed of fibers with small diameter (<20 microm); have been poorly investigated. This study investigates the variations, imposed by the NaOH treatment, in the physical and tensile properties of micro-fibrous polyethylene terephthalate mats. Polyethylene terephthalate webs with two different average fiber diameters of 6+/-2.5 and 10+/-4 microm were produced by melt blowing process. A number of these webs were consolidated to prepare fibrous matrices using a thermal treatment. The matrices were treated using NaOH 1 N at 65 degrees C for various durations (ranging from 20 min to 24 h). In addition to their physical properties such as weight loss, thickness, porosity, shrinkage and surface density; their morphology and tensile properties were also evaluated using scanning electron microscopy and micromechanical tester, respectively. In general, by increasing treatment duration, weight loss, porosity, and shrinkage increased, while thickness and density decreased. As a result of treatment duration, pores appeared on the surface of individual fibers, and tensile stress and Young's modulus decreased while tensile strain increased. Mats with different fiber diameters showed different physical and mechanical properties. These findings suggested that the structure of the matrices and the properties required for its end use, for biomedical applications including scaffolding materials for tissue engineering, should be considered in selecting NaOH treatment condition. (c) 2010. Published by Elsevier Ltd.

  2. Angiomatoid fibrous histiocytoma: novel MR imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Salutario J.; Vinson, Emily N. [Duke University Medical Center, Department of Radiology, Durham, NC (United States); Moreno, Courtney Coursey [Emory University School of Medicine, Department of Radiology and Imaging Sciences, Atlanta, GA (United States); Dodd, Leslie G. [University of North Carolina School of Medicine, Department of Pathology and Laboratory Medicine, Chapel Hill, NC (United States); Brigman, Brian E. [Duke University Medical Center, Department of Orthopedic Surgery, Durham, NC (United States)

    2016-05-15

    To describe novel MR imaging features, and clinical characteristics of soft tissue angiomatoid fibrous histiocytoma (AFH) at presentation, local recurrence, and metastases. We described the MRI findings of six cases of histologically proven AFH. Pathologic findings, clinical presentation, and outcome were reviewed. Lesions were primarily cystic. At initial presentation, tumors were surrounded by low signal intensity fibrous pseudocapsule. High signal intensity consistent with the lymphoplasmacytic infiltrate was seen in T2-weighted and post-contrast images as a rim over the hypointense pseudocapsule (double rim sign). High signal intensity infiltrating tumoral cords extended into adjacent tissues, through pseudocapsular defects on T2-weighted and post-contrast images. The cystic component and tumor cell nodularity were demonstrated at post-contrast images. Clinically, lesions were often thought to be benign, underwent marginal resection, developed local recurrence, and one developed second recurrence consisting of metastases. Recurrent tumors appeared as multiple masses, misinterpreted as post-surgical changes. An intramuscular recurrence demonstrated double rim and infiltrating margin. A predominantly well-circumscribed, primarily cystic mass with double-rim and marginal infiltration on MRI suggests the possibility of AFH, in particular in child or young adult. Inclusion of these novel observations in AFH differential diagnosis may have a significant impact on treatment and prevention of recurrence. (orig.)

  3. Self-Organization of Bioinspired Fibrous Surfaces

    Science.gov (United States)

    Kang, Sung Hoon

    Nature uses fibrous surfaces for a wide range of functions such as sensing, adhesion, structural color, and self-cleaning. However, little is known about how fiber properties enable them to self-organize into diverse and complex functional forms. Using polymeric micro/nanofiber arrays with tunable properties as model systems, we demonstrate how the combination of mechanical and surface properties can be harnessed to transform an array of anchored nanofibers into a variety of complex, hierarchically organized dynamic functional surfaces. We show that the delicate balance between fiber elasticity and surface adhesion plays a critical role in determining the shape, chirality, and hierarchy of the assembled structures. We further report a strategy for controlling the long-range order of fiber assemblies by manipulating the shape and movement of the liquid-vapor interface. Our study provides fundamental understanding of the pattern formation by self-organization of bioinspired fibrous surfaces. Moreover, our new strategies offer a foundation for designing a vast assortment of functional surfaces with adhesive, optical, water-repellent, capture and release, and many more capabilities with the structural and dynamic sophistication of their biological counterparts.

  4. Geometrical modeling of fibrous materials under compression

    Science.gov (United States)

    Maze, Benoit; Tafreshi, Hooman Vahedi; Pourdeyhimi, Behnam

    2007-10-01

    Many fibrous materials such as nonwovens are consolidated via compaction rolls in a so-called calendering process. Hot rolls compress the fiber assembly and cause fiber-to-fiber bonding resulting in a strong yet porous structure. In this paper, we describe an algorithm for generating three dimensional virtual fiberwebs and simulating the geometrical changes that happen to the structure during the calendering process. Fibers are assumed to be continuous filaments with square cross sections lying randomly in the x or y direction. The fibers are assumed to be flexible to allow bending over one another during the compression process. Lateral displacement is not allowed during the compaction process. The algorithm also does not allow the fibers to interpenetrate or elongate and so the mass of the fibers is conserved. Bending of the fibers is modeled either by considering a constant "slope of bending" or constant "span of bending." The influence of the bending parameters on the propagation of compression through the material's thickness is discussed. In agreement with our experimental observations, it was found that the average solid volume fraction profile across the thickness becomes U shaped after the calendering. The application of these virtual structures in studying transport phenomena in fibrous materials is also demonstrated.

  5. Solitary fibrous tumor surrounding the carotid sheath.

    Science.gov (United States)

    Gómez-Oliveira, Guillermo; Alvarez-Flores, Modesto; Arribas-García, Ignacio; Martínez-Gimeno, Carlos

    2010-03-01

    Solitary fibrous tumors (SFTs) are rare spindle cell neoplasms that are mostly found arising from the pleura. Although SFTs recently have been reported in other regions, they are rare in the head and neck and have often been misdiagnosed due to their rarity. SFTs are benign in most cases. Clinically, SFTs usually manifest as well-circumscribed, slow-growing, smooth and painless masses. Symptoms are often minimal, although they may include sore throat, difficulty in swallowing, change of voice or trismus. CT-Scan and MRI are the most sensitive imaging procedures used. The treatment of choice is complete surgical excision of the lesion. Because recurrences have been noted up to 30 years after surgery, long-term follow up is mandatory. In this article, we present a case of a Solitary Fibrous Tumor arising in the parapharyngeal space in a 20-year-old man, involving the carotid sheath, treated by surgical excision with no recurrence after 1 year. The clinical presentation, surgical management and pathological findings are described.

  6. Super-hydrophobic film prepared on zinc as corrosion barrier

    Energy Technology Data Exchange (ETDEWEB)

    Wang Peng [Key Lab of Corrosion Science, Shandong Province, Institute of Oceanology, Chinese Academy of Sciences, 7 Naihai Road, Qingdao 266071 (China); Zhang Dun, E-mail: Zhangdun@qdio.ac.c [Key Lab of Corrosion Science, Shandong Province, Institute of Oceanology, Chinese Academy of Sciences, 7 Naihai Road, Qingdao 266071 (China); Qiu Ri [Key Lab of Corrosion Science, Shandong Province, Institute of Oceanology, Chinese Academy of Sciences, 7 Naihai Road, Qingdao 266071 (China); Graduate School of the Chinese Academy of Sciences, 19 (Jia) Yuquan Road, Beijing 100039 (China); Hou Baorong [Key Lab of Corrosion Science, Shandong Province, Institute of Oceanology, Chinese Academy of Sciences, 7 Naihai Road, Qingdao 266071 (China)

    2011-06-15

    Research highlights: {yields} Super-hydrophobic film was prepared on zinc surface. {yields} The air trapped in film can dramatically improve the anti-corrosion property. {yields} The air trapped behaves as dielectric for a pure parallel plate capacitor. {yields} The air enhances the contribution of film to the anti-corrosion property. {yields} Without the help of air, the film itself can only present feeble inhibition effect. - Abstract: Potentiostatic electrolysis was carried out to prepare super-hydrophobic film on the surface of metallic zinc. The resultant film was examined by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, electrochemical measurements, and contact angle test. The super-hydrophobic property of the film results from the air trapped among the sheets of zinc tetradecanoate. This air behaves as a dielectric for a pure parallel plate capacitor, thereby inhibiting electron transfer between the electrolyte and the substrate. The air can also enhance the contribution of the film itself to protection performance.

  7. Boiling Heat Transfer on Superhydrophilic, Superhydrophobic, and Superbiphilic Surfaces

    CERN Document Server

    Betz, Amy Rachel; Kim, Chang-Jin 'CJ'; Attinger, Daniel

    2012-01-01

    With recent advances in micro- and nanofabrication, superhydrophilic and superhydrophobic surfaces have been developed. The statics and dynamics of fluids on these surfaces have been well characterized. However, few investigations have been made into the potential of these surfaces to control and enhance other transport phenomena. In this article, we characterize pool boiling on surfaces with wettabilities varied from superhydrophobic to superhydrophilic, and provide nucleation measurements. The most interesting result of our measurements is that the largest heat transfer coefficients are reached not on surfaces with spatially uniform wettability, but on biphilic surfaces, which juxtapose hydrophilic and hydrophobic regions. We develop an analytical model that describes how biphilic surfaces effectively manage the vapor and liquid transport, delaying critical heat flux and maximizing the heat transfer coefficient. Finally, we manufacture and test the first superbiphilic surfaces (juxtaposing superhydrophobic ...

  8. Spontaneous Jumping of Coalescing Drops on a Superhydrophobic Surface

    Science.gov (United States)

    Boreyko, Jonathan; Chen, Chuan-Hua

    2009-11-01

    When micrometric drops coalesce in-plane on a superhydrophobic surface, a surprising out-of-plane jumping motion was observed. Such jumping motion triggered by drop coalescence was reproduced on a Leidenfrost surface. High-speed imaging revealed that this jumping motion results from the elastic interaction of the bridged drops with the superhydrophobic/Leidenfrost surface. Experiments on both the superhydrophobic and Leidenfrost surfaces compare favorably to a simple scaling model relating the kinetic energy of the merged drop to the surface energy released upon coalescence. The spontaneous jumping motion on water repellent surfaces enables the autonomous removal of water condensate independently of gravity; this process is highly desirable for sustained dropwise condensation.

  9. Spontaneous Jumping of Coalescing Drops on a Superhydrophobic Surface

    CERN Document Server

    Boreyko, Jonathan

    2009-01-01

    When micrometric drops coalesce in-plane on a superhydrophobic surface, a surprising out-of-plane jumping motion was observed. Such jumping motion triggered by drop coalescence was reproduced on a Leidenfrost surface. High-speed imaging revealed that this jumping motion results from the elastic interaction of the bridged drops with the superhydrophobic/Leidenfrost surface. Experiments on both the superhydrophobic and Leidenfrost surfaces compare favorably to a simple scaling model relating the kinetic energy of the merged drop to the surface energy released upon coalescence. The spontaneous jumping motion on water repellent surfaces enables the autonomous removal of water condensate independently of gravity; this process is highly desirable for sustained dropwise condensation.

  10. Nanostructured superhydrophobic films synthesized by electrodeposition of fluorinated polyindoles.

    Science.gov (United States)

    Ramos Chagas, Gabriela; Darmanin, Thierry; Guittard, Frédéric

    2015-01-01

    Materials with bioinspired superhydrophobic properties are highly desirable for many potential applications. Here, nine novel monomers derived from indole are synthesized to obtain these properties by electropolymerization. These monomers differ by the length (C4F9, C6F13 and C8F17) and the position (4-, 5- and 6-position of indole) of the perfluorinated substituent. Polymeric films were obtained with C4F9 and C6F13 chains and differences in the surface morphology depend especially on the substituent position. The polyindoles exhibited hydrophobic and superhydrophobic properties even with a very low roughness. The best results are obtained with PIndole-6-F 6 for which superhydrophobic and highly oleophobic properties are obtained due to the presence of spherical nanoparticles and low surface energy compounds.

  11. Nanostructured superhydrophobic films synthesized by electrodeposition of fluorinated polyindoles

    Directory of Open Access Journals (Sweden)

    Gabriela Ramos Chagas

    2015-10-01

    Full Text Available Materials with bioinspired superhydrophobic properties are highly desirable for many potential applications. Here, nine novel monomers derived from indole are synthesized to obtain these properties by electropolymerization. These monomers differ by the length (C4F9, C6F13 and C8F17 and the position (4-, 5- and 6-position of indole of the perfluorinated substituent. Polymeric films were obtained with C4F9 and C6F13 chains and differences in the surface morphology depend especially on the substituent position. The polyindoles exhibited hydrophobic and superhydrophobic properties even with a very low roughness. The best results are obtained with PIndole-6-F6 for which superhydrophobic and highly oleophobic properties are obtained due to the presence of spherical nanoparticles and low surface energy compounds.

  12. Composition for forming an optically transparent, superhydrophobic coating

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, John T.; Lewis, Linda A.

    2015-12-29

    A composition for producing an optically clear, well bonded superhydrophobic coating includes a plurality of hydrophobic particles comprising an average particle size of about 200 nm or less, a binder at a binder concentration of from about 0.1 wt. % to about 0.5 wt. %, and a solvent. The hydrophobic particles may be present in the composition at a particle concentration of from about 0.1 wt. % to about 1 wt. %. An optically transparent, superhydrophobic surface includes a substrate, a plurality of hydrophobic particles having an average particle size of about 200 nm or less dispersed over the substrate, and a discontinuous binder layer bonding the hydrophobic particles to the substrate, where the hydrophobic particles and the binder layer form an optically transparent, superhydrophobic coating.

  13. Superhydrophobic paper with superior stability against deformations and humidity

    Science.gov (United States)

    Wang, Nan; Xiong, Dangsheng; Pan, Sai; Deng, Yaling; Shi, Yan; Wang, Kun

    2016-12-01

    Superhydrophobic coatings on paper were achieved by means of incorporating micro-nano hierarchical topography, where the water droplet was repelled and rested in a spherical shape. A silica sol, which was prepared using tetraethylorthosilicate (TEOS) as precursor and trimethylethoxysilane (TMES) as co-precursor, was poured on the paper to form a superhydrophobic surface. The coating was fluorine-free, environmentally friend, and could be easily fabricated on different kinds of papers. Besides, the transmittance of prepared coating reached up to 92% in visible light range, and the words on treated paper showed a good visualization. Moreover, the treated paper showed superior mechanical durability against 100 times of deformation, remarkable stability towards both the acidic and basic solutions. The treated paper could withstand 70 cycles of water condensation test (from 60 °C, 90% relative humidity to 10 °C) without losing superhydrophobicity, suggesting a long-term protection for paper.

  14. Composition for forming an optically transparent, superhydrophobic coating

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, John T.; Lewis, Linda A.

    2015-12-29

    A composition for producing an optically clear, well bonded superhydrophobic coating includes a plurality of hydrophobic particles comprising an average particle size of about 200 nm or less, a binder at a binder concentration of from about 0.1 wt. % to about 0.5 wt. %, and a solvent. The hydrophobic particles may be present in the composition at a particle concentration of from about 0.1 wt. % to about 1 wt. %. An optically transparent, superhydrophobic surface includes a substrate, a plurality of hydrophobic particles having an average particle size of about 200 nm or less dispersed over the substrate, and a discontinuous binder layer bonding the hydrophobic particles to the substrate, where the hydrophobic particles and the binder layer form an optically transparent, superhydrophobic coating.

  15. Superhydrophobic optically transparent silica films formed with a eutectic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Xiu Yonghao [School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0100 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, GA 30332-0245 (United States); Xiao Fei [School of Materials Science and Engineering, Fudan University, 220 Handan Road, Shanghai 200433 China (China); Hess, Dennis W. [School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0100 (United States)], E-mail: dennis.hess@chbe.gatech.edu; Wong, C.P. [School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, GA 30332-0245 (United States)], E-mail: cp.wong@mse.gatech.edu

    2009-01-01

    A eutectic liquid (choline chloride and urea) that served as a templating agent in sol-gel processing was used to prepare thin silica films on glass microscope slides. Subsequent extraction of the eutectic liquid yielded a film with a rough surface. After treating the film surface with a fluoroalkyl silane, the surface became superhydrophobic with a contact angle {approx} 170 deg. and a contact angle hysteresis < 10 deg. The optical transmittance of the film coated on the glass slide was comparable to that of the microscope glass slide. Atomic Force Microscopy (AFM) was used to characterize the surface structures; a tipless probe allowed measurement of the force of interaction with superhydrophobic surfaces. The interaction force between the AFM probe and the superhydrophobic surface was reduced greatly compared to that between the probe and the flat surface treated with fluoroalkyl silane.

  16. One-step electrodeposition process to fabricate cathodic superhydrophobic surface

    Energy Technology Data Exchange (ETDEWEB)

    Chen Zhi, E-mail: c2002z@nwpu.edu.cn [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710129 (China); Li Feng [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710129 (China); Hao Limei [Department of Applied Physics, Xi' an University of Science and Technology, Xi' an 710054 (China); Chen Anqi; Kong Youchao [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710129 (China)

    2011-12-01

    In this work, a rapid one-step process is developed to fabricate superhydrophobic cathodic surface by electrodepositing copper plate in an electrolyte solution containing manganese chloride (MnCl{sub 2}{center_dot}4H{sub 2}O), myristic acid (CH{sub 3}(CH{sub 2}){sub 12}COOH) and ethanol. The superhydrophobic surfaces were characterized by means of scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The shortest electrolysis time for fabricating a superhydrophobic surface is about 1 min, the measured maximum contact angle is 163 Degree-Sign and rolling angle is less than 3 Degree-Sign . Furthermore, this method can be easily extended to other conductive materials. The approach is time-saving and cheap, and it is supposed to have a promising future in industrial fields.

  17. Shrink-induced superhydrophobic and antibacterial surfaces in consumer plastics.

    Science.gov (United States)

    Freschauf, Lauren R; McLane, Jolie; Sharma, Himanshu; Khine, Michelle

    2012-01-01

    Structurally modified superhydrophobic surfaces have become particularly desirable as stable antibacterial surfaces. Because their self-cleaning and water resistant properties prohibit bacteria growth, structurally modified superhydrophobic surfaces obviate bacterial resistance common with chemical agents, and therefore a robust and stable means to prevent bacteria growth is possible. In this study, we present a rapid fabrication method for creating such superhydrophobic surfaces in consumer hard plastic materials with resulting antibacterial effects. To replace complex fabrication materials and techniques, the initial mold is made with commodity shrink-wrap film and is compatible with large plastic roll-to-roll manufacturing and scale-up techniques. This method involves a purely structural modification free of chemical additives leading to its inherent consistency over time and successive recasting from the same molds. Finally, antibacterial properties are demonstrated in polystyrene (PS), polycarbonate (PC), and polyethylene (PE) by demonstrating the prevention of gram-negative Escherichia coli (E. coli) bacteria growth on our structured plastic surfaces.

  18. One-step electrodeposition process to fabricate cathodic superhydrophobic surface

    Science.gov (United States)

    Chen, Zhi; Li, Feng; Hao, Limei; Chen, Anqi; Kong, Youchao

    2011-12-01

    In this work, a rapid one-step process is developed to fabricate superhydrophobic cathodic surface by electrodepositing copper plate in an electrolyte solution containing manganese chloride (MnCl2·4H2O), myristic acid (CH3(CH2)12COOH) and ethanol. The superhydrophobic surfaces were characterized by means of scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The shortest electrolysis time for fabricating a superhydrophobic surface is about 1 min, the measured maximum contact angle is 163° and rolling angle is less than 3°. Furthermore, this method can be easily extended to other conductive materials. The approach is time-saving and cheap, and it is supposed to have a promising future in industrial fields.

  19. Nanostructured superhydrophobic films synthesized by electrodeposition of fluorinated polyindoles

    Science.gov (United States)

    Ramos Chagas, Gabriela; Darmanin, Thierry

    2015-01-01

    Summary Materials with bioinspired superhydrophobic properties are highly desirable for many potential applications. Here, nine novel monomers derived from indole are synthesized to obtain these properties by electropolymerization. These monomers differ by the length (C4F9, C6F13 and C8F17) and the position (4-, 5- and 6-position of indole) of the perfluorinated substituent. Polymeric films were obtained with C4F9 and C6F13 chains and differences in the surface morphology depend especially on the substituent position. The polyindoles exhibited hydrophobic and superhydrophobic properties even with a very low roughness. The best results are obtained with PIndole-6-F 6 for which superhydrophobic and highly oleophobic properties are obtained due to the presence of spherical nanoparticles and low surface energy compounds. PMID:26665079

  20. Superhydrophobic bionic surfaces with hierarchical microsphere/SWCNT composite arrays.

    Science.gov (United States)

    Li, Yue; Huang, Xing Jiu; Heo, Sung Hwan; Li, Cun Cheng; Choi, Yang Kyu; Cai, Wei Ping; Cho, Sung Oh

    2007-02-13

    Superhydrophobic bionic surfaces with hierarchical micro/nano structures were synthesized by decorating single-walled or multiwalled carbon nanotubes (CNTs) on monolayer polystyrene colloidal crystals using a wet chemical self-assembly technique and subsequent surface treatment with a low surface-energy material of fluoroalkylsilane. The bionic surfaces are based on the regularly ordered colloidal crystals, and thus the surfaces have a uniform superhydrophobic property on the whole surface. Moreover, the wettability of the bionic surface can be well controlled by changing the distribution density of CNTs or the size of polystyrene microspheres. The morphologies of the synthesized bionic surfaces bear much resemblance to natural lotus leaves, and the wettability exhibited remarkable superhydrophobicity with a water contact angle of about 165 degrees and a sliding angle of 5 degrees.

  1. From hydrophobic to superhydrophobic and superhydrophilic siloxanes by thermal treatment.

    Science.gov (United States)

    Karapanagiotis, Ioannis; Manoudis, Panagiotis N; Zurba, Andreea; Lampakis, Dimitrios

    2014-11-11

    The cross-influence effects of treatment temperature and time on the wettability of a siloxane elastomer is investigated in detail, through static and tilt contact angle measurements. The material is heated at 400, 500, 600, 650, 700, and 800 °C for various periods, ranging from 1 to 300 s. The siloxane surface is subjected to multiple wettability transitions with treatment time: from intrinsic hydrophobicity to superhydrophobicity (and water repellency) and then through intermediate stages (hydrophobicity and hydrophilicity) to superhydrophilicity. For the time scale used herein (1-300 s), this scenario is recorded for treatment at 650, 700, and 800 °C. For treatment at lower temperatures (400, 500, and 600 °C) only the first transition, from intrinsic hydrophobicity to superhydrophobicity, is recorded. Scanning electron microscopy, micro-Fourier transform infrared (micro-FTIR), and micro-Raman spectroscopies are employed to correlate the aforementioned wettability transitions with structural and chemical changes of the siloxane surface, developed during thermal treatment. It is shown that the first transition from intrinsic hydrophobicity to superhydrophobicity is accompanied by a severe surface-structure evolution that increases surface roughness. Once superhydrophobicity is achieved, the surface structure reaches a saturation point and it is not subjected to any other change with further thermal treatment. FTIR spectroscopy shows that the intensity of the O-H/C-H peaks increases/decreases with treatment time, and Raman measurements show that the C-Si-C vibrations gradually disappear with treatment time. The evaporation of a droplet resting on a superhydrophobic, water-repellent siloxane surface, which was produced after appropriate thermal treatment, is monitored. It is shown that droplet evaporation initially follows the constant contact area mode. At later evaporation stages, a transition to the constant contact angle mode is recorded. Finally, it is

  2. Electrospun nanofibrous mats containing quaternized chitosan and polylactide with in vitro antitumor activity against HeLa cells.

    Science.gov (United States)

    Ignatova, Milena G; Manolova, Nevena E; Toshkova, Reneta A; Rashkov, Iliya B; Gardeva, Elena G; Yossifova, Lilia S; Alexandrov, Marin T

    2010-06-14

    Nanofibrous materials containing the antitumor drug doxorubicin hydrochloride (DOX) were easily prepared using a one-step method by electrospinning of DOX/poly(L-lactide-co-D,L-lactide) (coPLA) and DOX/quaternized chitosan (QCh)/coPLA solutions. The pristine and DOX-containing mats were characterized by ATR-FTIR and X-ray photoelectron spectroscopy (XPS). The release rate of DOX from the prepared fibers increased with the increase in DOX content. The DOX release process was diffusion-controlled. MTT cell viability studies revealed that incorporation of DOX and QCh in the nanofibrous mats led to a significant reduction in the HeLa cells viability. It was found, that the antitumor efficacy of the DOX-containing mats at 6 h was higher than that of the free DOX. SEM, TEM, and fluorescence microscopic observations confirmed that the antitumor effect of QCh-based and DOX-containing fibrous mats was mainly due to induction of apoptosis in the HeLa cells.

  3. The Effect Of microbial Mats In The Decay Of Anurans With Implications For Understanding Taphonomic Processes In The Fossil Record

    Science.gov (United States)

    Iniesto, M.; Villalba, I.; Buscalioni, A. D.; Guerrero, M. C.; López-Archilla, A. I.

    2017-01-01

    The pattern and sequence of the decomposition of the Pipidae African dwarf frog (Hymenochirus boettgeri) is tracked in an experiment with microbial mats in order to explore soft tissue preservation over three years. Frog decay in microbial mats is preceded by rapid entombment (25–30 days) and mediated by the formation of a sarcophagus, which is built by a complex microbial community. The frog carcasses maintained a variety of soft tissues for years. Labile organic structures show greater durability within the mat, cells maintain their general shape (bone marrow cells and adipocytes), and muscles and connective tissues (adipose and fibrous tendons) exhibit their original organic structures. In addition, other soft tissues are promptly mineralized (day 540) in a Ca-rich carbonate phase (encephalic tectum) or enriched in sulphur residues (integumentary system). The result is coherent with a bias in soft-tissue preservation, as some tissues are more likely to be conserved than others. The outcomes support observations of exceptionally preserved fossil anurans (adults and tadpoles). Decomposition in mats shows singular conditions of pH and dissolved oxygen. Mineralization processes could be more diverse than in simple heterotrophic biofilms, opening new taphonomic processes that have yet to be explored. PMID:28338095

  4. The influence of specimen thickness and alignment on the material and failure properties of electrospun polycaprolactone nanofiber mats.

    Science.gov (United States)

    Mubyana, Kuwabo; Koppes, Ryan A; Lee, Kristen L; Cooper, James A; Corr, David T

    2016-11-01

    Electrospinning is a versatile fabrication technique that has been recently expanded to create nanofibrous structures that mimic ECM topography. Like many materials, electrospun constructs are typically characterized on a smaller scale, and scaled up for various applications. This established practice is based on the assumption that material properties, such as toughness, failure stress and strain, are intrinsic to the material, and thus will not be influenced by specimen geometry. However, we hypothesized that the material and failure properties of electrospun nanofiber mats vary with specimen thickness. To test this, we mechanically characterized polycaprolactone (PCL) nanofiber mats of three different thicknesses in response to constant rate elongation to failure. To identify if any observed thickness-dependence could be attributed to fiber alignment, such as the effects of fiber reorientation during elongation, these tests were performed in mats with either random or aligned nanofiber orientation. Contrary to our hypothesis, the failure strain was conserved across the different thicknesses, indicating similar maximal elongation for specimens of different thickness. However, in both the aligned and randomly oriented groups, the ultimate tensile stress, short-range modulus, yield modulus, and toughness all decreased with increasing mat thickness, thereby indicating that these are not intrinsic material properties. These findings have important implications in engineered scaffolds for fibrous and soft tissue applications (e.g., tendon, ligament, muscle, and skin), where such oversights could result in unwanted laxity or reduced resistance to failure. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2794-2800, 2016.

  5. Fibrous microcapsules and methods of assembly and use thereof

    Energy Technology Data Exchange (ETDEWEB)

    Stupp, Samuel; Rozkiewicz, Dorota

    2015-01-27

    The present invention relates to assembly of peptide amphiphiles and biopolymers into fibrous microcapsules, and uses thereof. In particular, the present invention provides devices, compositions, and methods for interfacial self-assembly of peptide amphiphiles and biopolyments into fibrous microcapsules, and uses thereof.

  6. Marfan syndrome with multiseptate pneumothorax and mandibular fibrous dysplasia

    Directory of Open Access Journals (Sweden)

    Kate A

    2009-01-01

    Full Text Available We describe a rare case of pneumothorax due to Marfan syndrome associated with fibrous dysplasia of the mandible. Marfan syndrome and fibrous dysplasia were possibly due to a common etiological factor. The association between the two and other tumors described in literature related to Marfan syndrome is discussed.

  7. Wetting of soap bubbles on hydrophilic, hydrophobic and superhydrophobic surfaces

    CERN Document Server

    Arscott, Steve

    2013-01-01

    Wetting of sessile bubbles on solid and liquid surfaces has been studied. A model is presented for the contact angle of a sessile bubble based on a modified Young equation - the experimental results agree with the model. A hydrophilic surface results in a bubble contact angle of 90 deg whereas on a superhydrophobic surface one observes 134 deg. For hydrophilic surfaces, the bubble angle diminishes with bubble radius - whereas on a superhydrophobic surface, the bubble angle increases. The size of the Plateau borders governs the bubble contact angle - depending on the wetting of the surface.

  8. Influence of Liquid Viscosity on Droplet Impingement on Superhydrophobic Surfaces

    CERN Document Server

    Pearson, John T; Webb, Brent W

    2010-01-01

    This fluid dynamics video describes droplet impingement experiments performed on superhydrophobic surfaces. When droplets of pure water are impinged upon superhydrophobic surfaces, a region of thin coherent jets are observed for Weber numbers between 5 and 15. Also, peripheral splashing is observed for Weber numbers above about 200. When the viscosity of the droplet is increased by mixing glycerol with the water, the thin jets are not observed and peripheral splashing is delayed somewhat. In the Weber number range where pure water droplets are observed to splash peripherally, the water/glycerol droplets are observed to have two-pronged jets.

  9. Condensation heat transfer on two-tier superhydrophobic surfaces

    Science.gov (United States)

    Cheng, Jiangtao; Vandadi, Aref; Chen, Chung-Lung

    2012-09-01

    We investigated water vapor condensation on a two-tier superhydrophobic surface in an environmental scanning electron microscope (ESEM) and in a customer-designed vapor chamber. We have observed continuous dropwise condensation (DWC) on the textured surface in ESEM. However, a film layer of condensate was formed on the multiscale texture in the vapor chamber. Due to the filmwise condensation, the condensation heat transfer coefficient of the superhydrophobic surface is lower than that of a flat hydrophobic surface especially under high heat flux situations. Our studies indicate that adaptive and prompt condensate droplet purging is the dominant factor for sustaining long-term DWC.

  10. Fabrication of superhydrophobic and lyophobic slippery surface on steel substrate

    Science.gov (United States)

    Wang, Nan; Xiong, Dangsheng; Pan, Sai; Deng, Yaling; Shi, Yan

    2016-11-01

    Superhydrophobic/oleophilic coating was prepared on steel via wet chemical etching, and followed by surface modification. Surface grafting was manifested to be realized mainly on the oxidized area. Slippery liquid infused porous surface(s) (SLIPS) was prepared by infusing perfluorinated lubricant into the prepared superhydrophobic coating, to repel water, coffee, kerosene, and even hexane, suggesting a transition from superoleophilicity to lyophobicity. Furthermore, the lyohobicity was accessible only when the substrate is fluorinated. Moreover, the kinematic viscosity was demonstrated to be negatively correlated to the traveling speed of the liquids on the SLIPS.

  11. High contact angle hysteresis of superhydrophobic surfaces: Hydrophobic defects

    Science.gov (United States)

    Chang, Feng-Ming; Hong, Siang-Jie; Sheng, Yu-Jane; Tsao, Heng-Kwong

    2009-08-01

    A typical superhydrophobic surface is essentially nonadhesive and exhibits very low water contact angle (CA) hysteresis, so-called Lotus effect. However, leaves of some plants such as scallion and garlic with an advancing angle exceeding 150° show very serious CA hysteresis. Although surface roughness and epicuticular wax can explain the very high advancing CA, our analysis indicates that the unusual hydrophobic defect, diallyl disulfide, is the key element responsible for contact line pinning on allium leaves. After smearing diallyl disulfide on an extended polytetrafluoroethylene (PTFE) film, which is originally absent of CA hysteresis, the surface remains superhydrophobic but becomes highly adhesive.

  12. How Water Advances on Superhydrophobic Surfaces

    Science.gov (United States)

    Schellenberger, Frank; Encinas, Noemí; Vollmer, Doris; Butt, Hans-Jürgen

    2016-03-01

    Superliquid repellency can be achieved by nano- and microstructuring surfaces in such a way that protrusions entrap air underneath the liquid. It is still not known how the three-phase contact line advances on such structured surfaces. In contrast to a smooth surface, where the contact line can advance continuously, on a superliquid-repellent surface, the contact line has to overcome an air gap between protrusions. Here, we apply laser scanning confocal microscopy to get the first microscopic videos of water drops advancing on a superhydrophobic array of micropillars. In contrast to common belief, the liquid surface gradually bends down until it touches the top face of the next micropillars. The apparent advancing contact angle is 180°. On the receding side, pinning to the top faces of the micropillars determines the apparent receding contact angle. Based on these observations, we propose that the apparent receding contact angle should be used for characterizing superliquid-repellent surfaces rather than the apparent advancing contact angle and hysteresis.

  13. Collapse of superhydrophobicity on nanopillared surfaces

    Science.gov (United States)

    Amabili, Matteo; Giacomello, Alberto; Meloni, Simone; Casciola, Carlo Massimo

    2017-03-01

    The mechanism of the collapse of the superhydrophobic state is elucidated for submerged nanoscale textures forming a three-dimensional interconnected vapor domain. This key issue for the design of nanotextures poses significant simulation challenges as it is characterized by diverse time and length scales. State-of-the-art atomistic rare events simulations are applied for overcoming the long time scales connected with the large free energy barriers. In such interconnected surface cavities wetting starts with the formation of a liquid finger between two pillars. This break of symmetry induces a more gentle bend in the rest of the liquid-vapor interface, which triggers the wetting of the neighboring pillars. This collective mechanism, involving the wetting of several pillars at the same time, could not be captured by previous atomistic simulations using surface models comprising a small number of pillars (often just one). Atomistic results are interpreted in terms of a sharp-interface continuum model which suggests that line tension, condensation, and other nanoscale phenomena play a minor role in the simulated conditions.

  14. Hot embossing of PTFE: Towards superhydrophobic surfaces

    Science.gov (United States)

    Jucius, D.; Grigaliūnas, V.; Mikolajūnas, M.; Guobienė, A.; Kopustinskas, V.; Gudonytė, A.; Narmontas, P.

    2011-01-01

    Three types of reusable stamps with features in the form of 2D arrays of pits having lateral dimensions in the range of 2-80 μm and heights of 1.5-15 μm were successfully employed for the hot embossing of PTFE at temperatures up to 50 °C above the glass transition temperature of PTFE amorphous phase. Due to the softening of PTFE at the temperatures used in this study, we were able to decrease imprint pressure significantly when comparing with the imprint conditions reported by other authors. Impact of the imprint temperature, pressure and time on the fidelity of pattern transfer as well as on water repellency was tested. The best results of embossing were achieved by applying pressure of 10 kg/cm 2 for 2 min at 170 °C. In this case, flattening of a natural PTFE roughness and pretty accurate deep replicas of the stamp patterns were observable on the whole imprinted area. Improvement in water repellency was largest for the samples imprinted by Ni stamp patterned with a 2D array of 2 μm square pits spaced by the same dimension and having a depth of 1.5 μm. Cassie-Baxter wetting regime was observed for the deepest imprints with water contact angles up to the superhydrophobic limit.

  15. Electrospun nanocomposite fibrous polymer electrolyte for secondary lithium battery applications

    Science.gov (United States)

    Padmaraj, O.; Rao, B. Nageswara; Jena, Paramananda; Venkateswarlu, M.; Satyanarayana, N.

    2014-04-01

    Hybrid nanocomposite [poly(vinylidene fluoride -co- hexafluoropropylene) (PVdF-co-HFP)/magnesium aluminate (MgAl2O4)] fibrous polymer membranes were prepared by electrospinning method. The prepared pure and nanocomposite fibrous polymer electrolyte membranes were soaked into the liquid electrolyte 1M LiPF6 in EC: DEC (1:1,v/v). XRD and SEM are used to study the structural and morphological studies of nanocomposite electrospun fibrous polymer membranes. The nanocomposite fibrous polymer electrolyte membrane with 5 wt.% of MgAl2O4 exhibits high ionic conductivity of 2.80 × 10-3 S/cm at room temperature. The charge-discharge capacity of Li/LiCoO2 coin cells composed of the newly prepared nanocomposite [(16 wt.%) PVdF-co-HFP+(5 wt.%) MgAl2O4] fibrous polymer electrolyte membrane was also studied and compared with commercial Celgard separator.

  16. A solitary fibrous tumor of the kidney

    Directory of Open Access Journals (Sweden)

    Anuruddha M Abeygunasekera

    2015-01-01

    Full Text Available A solitary fibrous tumor (SFT is an uncommon spindle cell neoplasm that usually occurs in the pleura, but may occur in extrapleural sites. Its occurrence in the kidney is rare. We report a SFT, clinically thought to be a renal cell carcinoma arising in the kidney of a 68-year-old female. The tumor was well-circumscribed and composed of a mixture of spindle cells and dense collagenous bands. Immunohistochemical studies revealed reactivity for CD34, CD99, and Bcl-2 protein, with no staining for keratin or muscle markers, confirming the diagnosis. The immunohistochemical study was the key to diagnosis. Several younger members of her family had colorectal and lung cancers suggesting the possibility of a familial or genetic susceptibility.

  17. Malignant fibrous histiocytoma of the abdominal wall

    Directory of Open Access Journals (Sweden)

    Arif Aslaner

    2015-01-01

    Full Text Available Malignant fibrous histiocytoma (MFH or undifferentiated pleomorphic sarcoma is a type of malignt neoplasm that arises from any soft tissue and bone involving extremities, abdomen and retroperitoneum. MFH of the external oblique abdominis muscle is rare. Surgical resection of the mass is the treatment of choice depending on the stage of the disease and the invasion depth of the tumor. Radiotherapy, chemotherapy and immunotherapy are the other treatment methods. We present a case of a 71-year old man with the diagnosis of MFH on external oblique muscle which was completely resected. We believe that adjuvant chemoradiotherapy following surgical resection of the tumor was the most appropriate treatment for this disease.

  18. Cutaneous changes in fibrous hamartoma of infancy

    Directory of Open Access Journals (Sweden)

    Pilar F-Eire

    2013-01-01

    Full Text Available Only a few published case of fibrous hamartoma of infancy (FHI have commented on the changes in the overlying skin. There are descriptions of individual cases with cutaneous hyperpigmentation, hypertrichosis and hyperhidrosis. It is interesting to describe our case because, to our knowledge, the altered pigmentation of the overlying skin, with hairs on the surface, and eccrine gland hyperplasia combined with abortive hair follicles has not been reported together in association with the FHI. We recommend that all the biopsies must be excisional including overlying skin, thus the epidermal and dermal adnexal changes can be assessed in the microscopic evaluation which could have relevant implications from clinical and embryological point of view.

  19. [Non-ossifying fibroma (metaphyseal fibrous defect)].

    Science.gov (United States)

    Rogozhin, D V; Konovalov, D M; Kozlov, A S; Talalaev, A G; Ektova, A P

    2016-01-01

    Non-ossifying fibroma (NOF) or metaphyseal fibrous defect (MFD) is benign fibroblast proliferation with the presence of osteoclast-like multinucleated giant cells. The most cases of NOF/MFD occur in the metaphysis of the long tubular bones of the lower extremities, more commonly in the metaphysis of the femur and in the proximal metaphysis of the tibia. This lesion has a characteristic X-ray pattern and requires no surgical intervention, except for cases of a pathologic fracture or a risk for the latter. The paper analyzes 35 NOF/MFD cases in children and adolescents. It has been found that one and all patients have undergone surgery, suggesting the low awareness of this abnormality among radiodiagnosticians, pathologists, and surgeons.

  20. Symptomatic fibrous lunato-triquetral coalition

    Energy Technology Data Exchange (ETDEWEB)

    Staebler, A.; Glaser, C.; Reiser, M. [Department of Diagnostic Radiology, Ludwig Maximilians University of Munich (Germany); Resnick, D. [Department of Radiology, Veterans Administration Medical Center, San Diego, CA (United States)

    1999-10-01

    In general, carpal coalitions are considered to be asymptomatic. Incomplete separated joints and associated changes similar to osteoarthritis and pseudoarthrosis are known as possible causes of wrist pain. We present the clinical history, plain-film, and MR imaging findings of two patients with symptomatic fibrous lunato-triquetral coalition. Conventional films disclosed a narrowed space between the lunate and triquetral bone with cysts and sclerosis similar to pseudoarthrosis. Magnetic resonance imaging showed bone marrow edema adjacent to the incomplete separated lunato-triquetral joint and Gd-DTPA enhancing fibrovascular tissue in the synovium and subarticular cysts, explaining the pain over the ulnar-sided wrist. Patients with congenital lunato-triquetral coalition may poorly tolerate stress loading or trauma, resulting in a symptomatic state similar to degenerative arthritis or pseudoarthrosis, which is demonstrated by enhanced MR imaging. (orig.) With 2 figs., 23 refs.

  1. Method of manufacturing fibrous hemostatic bandages

    Science.gov (United States)

    Larsen, Gustavo; Spretz, Ruben; Velarde-Ortiz, Raffet

    2012-09-04

    A method of manufacturing a sturdy and pliable fibrous hemostatic dressing by making fibers that maximally expose surface area per unit weight of active ingredients as a means for aiding in the clot forming process and as a means of minimizing waste of active ingredients. The method uses a rotating object to spin off a liquid biocompatible fiber precursor, which is added at its center. Fibers formed then deposit on a collector located at a distance from the rotating object creating a fiber layer on the collector. An electrical potential difference is maintained between the rotating disk and the collector. Then, a liquid procoagulation species is introduced at the center of the rotating disk such that it spins off the rotating disk and coats the fibers.

  2. Epicardial delivery of VEGF and cardiac stem cells guided by 3-dimensional PLLA mat enhancing cardiac regeneration and angiogenesis in acute myocardial infarction.

    Science.gov (United States)

    Chung, Hye-Jin; Kim, Jong-Tae; Kim, Hee-Jung; Kyung, Hei-Won; Katila, Pramila; Lee, Jeong-Han; Yang, Tae-Hyun; Yang, Young-Il; Lee, Seung-Jin

    2015-05-10

    Congestive heart failure is mostly resulted in a consequence of the limited myocardial regeneration capacity after acute myocardial infarction. Targeted delivery of proangiogenic factors and/or stem cells to the ischemic myocardium is a promising strategy for enhancing their local and sustained therapeutic effects. Herein, we designed an epicardial delivery system of vascular endothelial growth factor (VEGF) and cardiac stem cells (CSCs) using poly(l-lactic acid) (PLLA) mat applied to the acutely infarcted myocardium. The fibrous VEGF-loaded PLLA mat was fabricated by an electrospinning method using PLLA solution emulsified VEGF. This mat not only allowed for sustained release of VEGF for 4weeks but boosted migration and proliferation of both endothelial cells and CSCs in vitro. Furthermore, sustained release of VEGF showed a positive effect on in vitro capillary-like network formation of endothelial cells compared with bolus treatment of VEGF. PLLA mat provided a permissive 3-dimensional (3D) substratum that led to spontaneous cardiomyogenic differentiation of CSCs in vitro. Notably, sustained stimulation by VEGF-loaded PLLA mat resulted in a substantial increase in the expression of proangiogenic mRNAs of CSCs in vitro. The epicardially implanted VEGF-loaded PLLA mat showed modest effects on angiogenesis and cardiomyogenesis in the acutely infarcted hearts. However, co-implantation of VEGF and CSCs using the PLLA mat showed meaningful therapeutic effects on angiogenesis and cardiomyogenesis compared with controls, leading to reduced cardiac remodeling and enhanced global cardiac function. Collectively, the PLLA mat allowed a smart cargo that enabled the sustained release of VEGF and the delivery of CSCs, thereby synergistically inducing angiogenesis and cardiomyogenesis in acute myocardial infarction.

  3. Organic and mineral imprints in fossil photosynthetic mats of an East Antarctic lake.

    Science.gov (United States)

    Lepot, K; Compère, P; Gérard, E; Namsaraev, Z; Verleyen, E; Tavernier, I; Hodgson, D A; Vyverman, W; Gilbert, B; Wilmotte, A; Javaux, E J

    2014-09-01

    Lacustrine microbial mats in Antarctic ice-free oases are considered modern analogues of early microbial ecosystems as their primary production is generally dominated by cyanobacteria, the heterotrophic food chain typically truncated due to extreme environmental conditions, and they are geographically isolated. To better understand early fossilization and mineralization processes in this context, we studied the microstructure and chemistry of organo-mineral associations in a suite of sediments 50-4530 cal. years old from a lake in Skarvsnes, Lützow Holm Bay, East Antarctica. First, we report an exceptional preservation of fossil autotrophs and their biomolecules on millennial timescales. The pigment scytonemin is preserved inside cyanobacterial sheaths. As non-pigmented sheaths are also preserved, scytonemin likely played little role in the preservation of sheath polysaccharides, which have been cross-linked by ether bonds. Coccoids preserved thylakoids and autofluorescence of pigments such as carotenoids. This exceptional preservation of autotrophs in the fossil mats argues for limited biodegradation during and after deposition. Moreover, cell-shaped aggregates preserved sulfur-rich nanoglobules, supporting fossilization of instable intracellular byproducts of chemotrophic or phototrophic S-oxidizers. Second, we report a diversity of micro- to nanostructured CaCO3 precipitates intimately associated with extracellular polymeric substances, cyanobacteria, and/or other prokaryotes. Micro-peloids Type 1 display features that distinguish them from known carbonates crystallized in inorganic conditions: (i) Type 1A are often filled with globular nanocarbonates and/or surrounded by a fibrous fringe, (ii) Type 1B are empty and display ovoid to wrinkled fringes of nanocrystallites that can be radially oriented (fibrous or triangular) or multilayered, and (iii) all show small-size variations. Type 2 rounded carbonates 1-2 μm in diameter occurring inside autofluorescent

  4. Genipin cross-linked electrospun chitosan-based nanofibrous mat as tissue engineering scaffold

    Directory of Open Access Journals (Sweden)

    Esmaeil Mirzaei

    2014-04-01

    Full Text Available   Objective(s: To improve water stability of electrospun chitosan/ Polyethylene oxide (PEO nanofibers, genipin, a biocompatible and nontoxic agent, was used to crosslink chitosan based nanofibers.   Materials and Methods: Different amounts of genipin were added to the chitosan/PEO solutions, chitosan/PEO weight ratio 90/10 in 80 % acetic acid, and the solutions were then electrospun to form nanofibers. The spun nanofibers were exposed to water vapor to complete crosslinking. The nanofibrous membranes were subjected to detailed analysis by scanning electron microscopy (SEM, Fourier transform infrared-attenuated total reflection (FTIR-ATR spectroscopy, swelling test, MTT cytotoxicity, and cell attachment. Results: SEM images of electrospun mats showed that genipin-crosslinked nanofibers retained their fibrous structure after immerging in PBS (pH=7.4 for 24 hours, while the uncrosslinked samples lost their fibrous structure, indicating the water stability of genipin-crosslinked nanofibers. The genipin-crosslinked mats also showed no significant change in swelling ratio in comparison with uncrosslinked ones. FTIR-ATR spectrum of uncrosslinked and genipin-crosslinked chitosan nanofibers revealed the reaction between genipin and amino groups of chitosan. Cytotoxicity of genipin-crosslinked nanofibers was examined by MTT assay on human fibroblast cells in the presence of nanofibers extraction media. The genipin-crosslinked nanofibers did not show any toxic effects on fibroblast cells at the lowest and moderate amount of genipin. The fibroblast cells also showed a good adhesion on genipin-crosslinked nanofibers. Conclusion: This electrospun matrix would be used for biomedical applications such as wound dressing and scaffold for tissue engineering without the concern of toxicity.

  5. PREPARATION AND CHARACTERIZATION OF SUPERHYDROPHOBIC FEP-TEFLON SURFACES

    NARCIS (Netherlands)

    BUSSCHER, HJ; STOKROOS, [No Value; VANDERMEI, HC; ROUXHET, PG; SCHAKENRAAD, JM

    1992-01-01

    Superhydrophobic FEP-Teflon was prepared by argon ion etching followed by oxygen glow discharge treatment of commercially available FEP-Teflon sheet material. This combined treatment yielded an increase in water contact angle from 109-degrees to > 140-degrees. Ion etching alone caused a small increa

  6. Superhydrophobic bio-fibre surfaces via tailored grafting architecture.

    Science.gov (United States)

    Nyström, Daniel; Lindqvist, Josefina; Ostmark, Emma; Hult, Anders; Malmström, Eva

    2006-09-14

    Superhydrophobic bio-fibre surfaces with a micro-nano-binary surface structure have been achieved via the surface-confined grafting of glycidyl methacrylate, using a branched "graft-on-graft" architecture, followed by post-functionalisation to obtain fluorinated brushes.

  7. Frosting Behavior of Superhydrophobic Nanoarrays under Ultralow Temperature.

    Science.gov (United States)

    Zhang, Wenwen; Wang, Shanlin; Xiao, Zhen; Yu, Xinquan; Liang, Caihua; Zhang, Youfa

    2017-09-12

    Retarding and preventing frost formation at ultralow temperature has an increasing importance due to a wide range of applications of ultralow fluids in aerospace and industrial facilities. Recent efforts for developing antifrosting surfaces have been mostly devoted to utilizing lotus-leaf-inspired superhydrophobic surfaces. Whether the antifrosting performance of the superhydrophobic surface is still effective under ultralow temperature has not been elucidated clearly. Here, we investigated the frosting behavior of fabricated superhydrophobic ZnO nanoarrays under different temperature and different environment. The surface showed excellent performance in anticondensation and antifrosting when the surface temperature was approximately -20 °C. Although the frosting event inevitably occurs on all surfaces when the temperature is decreased from -50 to -150 °C, the frost accumulation on the superhydrophobic surfaces is always less than that on the untreated surfaces. Interestingly, the frost layer detaches from the surface within a short time and keeps the surface dry in the very beginning of the defrosting process. Further, there is no frost formation on the surface at -20 °C during 10 min testing when blowing compressed air and spraying methanol together or spraying methanol individually. It can reduce the height of the frost layer and increases the density when spraying methanol at -150 °C. Furthermore, the frost crystals on the top surface can been blown away due to the low adhesion of ice or frost. It provides a basic idea for solving the frosting problem under ultralow temperature while combined with other defrosting methods.

  8. Highly Flexible Superhydrophobic and Fire-Resistant Layered Inorganic Paper.

    Science.gov (United States)

    Chen, Fei-Fei; Zhu, Ying-Jie; Xiong, Zhi-Chao; Sun, Tuan-Wei; Shen, Yue-Qin

    2016-12-21

    Traditional paper made from plant cellulose fibers is easily destroyed by either liquid or fire. In addition, the paper making industry consumes a large amount of natural trees and thus causes serious environmental problems including excessive deforestation and pollution. In consideration of the intrinsic flammability of organics and minimizing the effects on the environment and creatures, biocompatible ultralong hydroxyapatite nanowires are an ideal building material for inorganic fire-resistant paper. Herein, a new kind of free-standing, highly flexible, superhydrophobic, and fire-resistant layered inorganic paper has been successfully prepared using ultralong hydroxyapatite nanowires as building blocks after the surface modification with sodium oleate. During the vacuum filtration, ultralong hydroxyapatite nanowires assemble into self-roughened setalike microfibers, avoiding the tedious fabrication process to construct the hierarchical structure; the self-roughened microfibers further form the inorganic paper with a nacrelike layered structure. We have demonstrated that the layered structure can significantly improve the resistance to mechanical destruction of the as-prepared superhydrophobic paper. The as-prepared superhydrophobic and fire-resistant inorganic paper shows excellent nonflammability, liquid repellency to various commercial drinks, high thermal stability, and self-cleaning property. Moreover, we have explored the potential applications of the superhydrophobic and fire-resistant inorganic paper as a highly effective adsorbent for oil/water separation, fire-shielding protector, and writing paper.

  9. Droplet impact on superhydrophobic surfaces fully decorated with cylindrical macrotextures.

    Science.gov (United States)

    Abolghasemibizaki, Mehran; Mohammadi, Reza

    2017-09-08

    Impacting on a superhydrophobic surface, water droplet spreads to a pancake shape and then retracts and bounces off. Although the collision time is mostly in the order of couple of 10ms for millimetric droplets, researchers have shown recently that decorating the superhydrophobic surface with a single macrotexture or intersecting ridge reduces this contact time if the droplet hits the texture or the intersection exactly in the center. Hence, covering the surface with ridges should address this hitting point restriction. Using an extruder-type 3D printer, we fabricated a superhydrophobic surface fully decorated with cylindrical ridges. The dynamic of water droplet impact on this surface at different impact velocities has been studied for varied droplet volumes and ridge sizes. Our data show that regardless of the location of the contact point, when the kinetic energy of the drop is sufficient to completely wet the ridges, the contact time reduces ∼13% as the consequence of ∼20% faster retraction. For higher impact velocity, the contact becomes shorter since the flattened drop splashes from the periphery. Moreover, the simplified, time-efficient and inexpensive method of fabricating the surfaces presented in this paper can be implemented in fabricating many versatile superhydrophobic surfaces with complex geometries. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Superhydrophobic/superoleophilic magnetic elastomers by laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Milionis, Athanasios, E-mail: am2vy@virginia.edu [Smart Materials-Nanophysics, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy); Fragouli, Despina; Brandi, Fernando; Liakos, Ioannis; Barroso, Suset [Smart Materials-Nanophysics, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy); Ruffilli, Roberta [Nanochemistry, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy); Athanassiou, Athanassia, E-mail: athanassia.athanassiou@iit.it [Smart Materials-Nanophysics, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy)

    2015-10-01

    Highlights: • We report the development of magnetic nanocomposite sheets. • Laser irradiation of the nanocomposites induces chemical and structural changes to the surface. • The laser-patterned surfaces exhibit superhydrophobicity and superoleophilicity. • The particle contribution in altering the surface and bulk properties of the material is studied. - Abstract: We report the development of magnetic nanocomposite sheets with superhydrophobic and supeoleophilic surfaces generated by laser ablation. Polydimethylsiloxane elastomer free-standing films, loaded homogeneously with 2% wt. carbon coated iron nanoparticles, were ablated by UV (248 nm), nanosecond laser pulses. The laser irradiation induces chemical and structural changes (both in micro- and nano-scale) to the surfaces of the nanocomposites rendering them superhydrophobic. The use of nanoparticles increases the UV light absorption efficiency of the nanocomposite samples, and thus facilitates the ablation process, since the number of pulses and the laser fluence required are greatly reduced compared to the bare polymer. Additionally the magnetic nanoparticles enhance significantly the superhydrophobic and oleophilic properties of the PDMS sheets, and provide to PDMS magnetic properties making possible its actuation by a weak external magnetic field. These nanocomposite elastomers can be considered for applications requiring magnetic MEMS for the controlled separation of liquids.

  11. Superhydrophobic coatings for aluminium surfaces synthesized by chemical etching process

    Directory of Open Access Journals (Sweden)

    Priya Varshney

    2016-10-01

    Full Text Available In this paper, the superhydrophobic coatings on aluminium surfaces were prepared by two-step (chemical etching followed by coating and one-step (chemical etching and coating in a single step processes using potassium hydroxide and lauric acid. Besides, surface immersion time in solutions was varied in both processes. Wettability and surface morphologies of treated aluminium surfaces were characterized using contact angle measurement technique and scanning electron microscopy, respectively. Microstructures are formed on the treated aluminium surfaces which lead to increase in contact angle of the surface (>150°. Also on increasing immersion time, contact angle further increases due to increase in size and depth of microstructures. Additionally, these superhydrophobic coatings show excellent self-cleaning and corrosion-resistant behavior. Water jet impact, floatation on water surface, and low temperature condensation tests assert the excellent water-repellent nature of coatings. Further, coatings are to be found mechanically, thermally, and ultraviolet stable. Along with, these coatings are found to be excellent regeneration ability as verified experimentally. Although aforesaid both processes generate durable and regenerable superhydrophobic aluminium surfaces with excellent self-cleaning, corrosion-resistant, and water-repellent characteristics, but one-step process is proved more efficient and less time consuming than two-step process and promises to produce superhydrophobic coatings for industrial applications.

  12. A Superhydrophobic Smart Coating for Flexible and Wearable Sensing Electronics.

    Science.gov (United States)

    Li, Lianhui; Bai, Yuanyuan; Li, Lili; Wang, Shuqi; Zhang, Ting

    2017-09-22

    Superhydrophobic surfaces have shown versatile applications in waterproofing, self-cleaning, drag reduction, selective absorption, etc. The most convenient and universally applicable approach to forming superhydrophobic surfaces is by coating; however, currently, superhydrophobic, smart coatings with flexibility and multiple functions for wearable sensing electronics are not yet reported. Here, a highly flexible multifunctional smart coating is fabricated by spray-coating multiwalled carbon nanotubes dispersed in a thermoplastic elastomer solution, followed by treatment with ethanol. The coatings not only endow various substrate materials with superhydrophobic surfaces, but can also respond to stretching, bending, and torsion-a property useful for flexible sensor applications. The coatings show superior sensitivity (gauge factor of 5.4-80), high resolution (1° of bending), a fast response time (<8 ms), a stable response over 5000 stretching-relaxing cycles, and wide sensing ranges (stretching: over 76%, bending: 0°-140°, torsion: 0-350 rad m(-1) ). Moreover, multifunctional coatings with thicknesses of only 1 µm can be directly applied to clothing for full-range and real-time detection of human motions, which also show extreme repellency to water, acid, and alkali, which helps the sensors to work under wet and corrosive conditions. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. A Mechanistic Study of Wetting Superhydrophobic Porous 3D Meshes

    Science.gov (United States)

    Yohe, Stefan T.; Freedman, Jonathan D.; Falde, Eric J.; Colson, Yolonda L.; Grinstaff, Mark W.

    2014-01-01

    Superhydrophobic, porous, 3D materials composed of poly( ε -caprolactone) (PCL) and the hydrophobic polymer dopant poly(glycerol monostearate-co- ε -caprolactone) (PGC-C18) are fabricated using the electrospinning technique. These 3D materials are distinct from 2D superhydrophobic surfaces, with maintenance of air at the surface as well as within the bulk of the material. These superhydrophobic materials float in water, and when held underwater and pressed, an air bubble is released and will rise to the surface. By changing the PGC-C18 doping concentration in the meshes and/or the fiber size from the micro- to nanoscale, the long-term stability of the entrapped air layer is controlled. The rate of water infiltration into the meshes, and the resulting displacement of the entrapped air, is quantitatively measured using X-ray computed tomography. The properties of the meshes are further probed using surfactants and solvents of different surface tensions. Finally, the application of hydraulic pressure is used to quantify the breakthrough pressure to wet the meshes. The tools for fabrication and analysis of these superhydrophobic materials as well as the ability to control the robustness of the entrapped air layer are highly desirable for a number of existing and emerging applications. PMID:25309305

  14. Facile Method to Prepare Superhydrophobic and Water Repellent Cellulosic Paper

    Directory of Open Access Journals (Sweden)

    Ioannis Karapanagiotis

    2015-01-01

    Full Text Available Silica nanoparticles (7 nm were dispersed in solutions of a silane/siloxane mixture. The dispersions were applied, by brush, on four types of paper: (i modern, unprinted (blank paper, (ii modern paper where a text was printed using a common laser jet printer, (iii a handmade paper sheet detached from an old book, and (iv Japanese tissue paper. It is shown that superhydrophobicity and water repellency were achieved on the surface of the deposited films, when high particle concentrations were used (≥1% w/v, corresponding to high static (θS ≈ 162° and low tilt (θt < 3° contact angles. To interpret these results, scanning electron microscopy (SEM was employed to observe the surface morphologies of the siloxane-nanoparticle films. Static contact angles, measured on surfaces that were prepared from dilute dispersions (particle concentration <1% w/v, increased with particle concentration and attained a maximum value (162° which corresponds to superhydrophobicity. Increasing further the particle concentration did not have any effect on θS. Colourimetric measurements showed that the superhydrophobic films had negligible effects on the aesthetic appearance of the treated papers. Furthermore, it is shown that the superhydrophobic character of the siloxane-nanoparticle films was stable over a wide range of pH.

  15. Two-Phase Flow Hydrodynamics in Superhydrophobic Channels

    Science.gov (United States)

    Stevens, Kimberly; Crockett, Julie; Maynes, Daniel; Iverson, Brian

    2015-11-01

    Superhydrophobic surfaces promote drop-wise condensation and droplet removal leading to the potential for increased thermal transport. Accordingly, great interest exists in using superhydrophobic surfaces in flow condensing environments, such as power generation and desalination. Adiabatic air-water mixtures were used to gain insight into the effect of hydrophobicity on two-phase flows and the hydrodynamics present in flow condensation. Pressure drop and onset of various flow regimes in hydrophilic, hydrophobic, and superhydrophobic mini (0.5 x 10 mm) channels were explored. Data for air/water mixtures with superficial Reynolds numbers from 20-200 and 250-1800, respectively, were obtained. Agreement between experimentally obtained pressure drops and correlations in literature for the conventional smooth control surfaces was better than 20 percent. Transitions between flow regimes for the hydrophobic and hydrophilic channels were similar to commonly recognized flow types. However, the superhydrophobic channel demonstrated significantly different flow regime behavior from conventional surfaces including a different shape of the air slugs, as discussed in the presentation.

  16. Methyltrimethoxysilane (MTMS)-based silica-iron oxide superhydrophobic nanocomposites.

    Science.gov (United States)

    Nadargi, Digambar; Gurav, Jyoti; Marioni, Miguel A; Romer, Sara; Matam, Santhosh; Koebel, Matthias M

    2015-12-01

    We report a facile synthesis of superhydrophobic silica-iron oxide nanocomposites via a co-precursor sol-gel process. The choice of the silica precursor (Methyltrimethoxysilane, MTMS) in combination with iron nitrate altered the pore structure dramatically. The influence of iron oxide doping on the structural properties of pristine MTMS aerogel is discussed.

  17. PREPARATION AND CHARACTERIZATION OF SUPERHYDROPHOBIC FEP-TEFLON SURFACES

    NARCIS (Netherlands)

    BUSSCHER, HJ; STOKROOS, [No Value; VANDERMEI, HC; ROUXHET, PG; SCHAKENRAAD, JM

    1992-01-01

    Superhydrophobic FEP-Teflon was prepared by argon ion etching followed by oxygen glow discharge treatment of commercially available FEP-Teflon sheet material. This combined treatment yielded an increase in water contact angle from 109-degrees to > 140-degrees. Ion etching alone caused a small increa

  18. Polystyrene/octadecyltrichlorosilane superhydrophobic coatings with hierarchical morphology

    OpenAIRE

    Demirel, A. Levent; Latthe, Sanjay S.

    2013-01-01

    A simple, one pot dip-coating process for the fabrication of super-hydrophobic coatings using polystyrene (PS) and octadecyltrichlorosilane (OTS) is introduced. The hierarchical coating morphology and the resulting surface wettability were controlled by OTS concentration and by the number of dipping cycles. The coatings showed good durability for applications.

  19. Drag reduction in turbulent flows over superhydrophobic surfaces

    Science.gov (United States)

    Daniello, Robert J.; Waterhouse, Nicholas E.; Rothstein, Jonathan P.

    2009-08-01

    In this paper, we demonstrate that periodic, micropatterned superhydrophobic surfaces, previously noted for their ability to provide laminar flow drag reduction, are capable of reducing drag in the turbulent flow regime. Superhydrophobic surfaces contain micro- or nanoscale hydrophobic features which can support a shear-free air-water interface between peaks in the surface topology. Particle image velocimetry and pressure drop measurements were used to observe significant slip velocities, shear stress, and pressure drop reductions corresponding to drag reductions approaching 50%. At a given Reynolds number, drag reduction is found to increase with increasing feature size and spacing, as in laminar flows. No observable drag reduction was noted in the laminar regime, consistent with previous experimental results for the channel geometry considered. The onset of drag reduction occurs at a critical Reynolds number where the viscous sublayer thickness approaches the scale of the superhydrophobic microfeatures and performance is seen to increase with further reduction in viscous sublayer height. These results indicate superhydrophobic surfaces may provide a significant drag reducing mechanism for marine vessels.

  20. Dynamics of Defrosting on Hydrophobic and Superhydrophobic Surfaces

    Science.gov (United States)

    Murphy, Kevin; McClintic, William; Lester, Kevin; Collier, Patrick; Boreyko, Jonathan

    2016-11-01

    It has recently been demonstrated that frost can grow in a suspended Cassie state on nanostructured superhydrophobic surfaces, which has implications for enhanced defrosting rates. However, to date there have been no direct comparisons of the defrosting kinetics of Cassie frost versus frost on conventional surfaces. Here, we fabricate a hybrid aluminum plate where half of the top face exhibits a superhydrophobic nanostructure while the other half is smooth and hydrophobic. By growing frost to varying thicknesses and melting at several tilt angles, we reveal the advantages and disadvantages of each surface with regards to the extent and speed of the shedding of melt water. For sufficiently thick frost layers, the Cassie state of frost on the superhydrophobic surface uniquely enabled the rapid and effective shedding of melt water even at low tilt angles. On the other hand, the hydrophobic surface was more effective at removing very thin frost sheets, as the reduced contact angle of water on the surface facilitated the coalescence of droplets to grow the melt water beyond the capillary length for gravitational removal. Therefore, the utilization of superhydrophobic versus hydrophobic surfaces for defrosting applications depends upon the context of the system conditions.

  1. Drop Impact upon Micro- and Nanostructured Superhydrophobic Surfaces

    NARCIS (Netherlands)

    Tsai, Peichun Amy; Pacheco Benito, Sergio; Pirat, C.; Lefferts, Leonardus; Lohse, Detlef

    2009-01-01

    We experimentally investigate drop impact dynamics onto different superhydrophobic surfaces, consisting of regular polymeric micropatterns and rough carbon nanofibers, with similar static contact angles. The main control parameters are the Weber number We and the roughness of the surface. At small

  2. Spray coating of superhydrophobic and angle-independent coloured films.

    Science.gov (United States)

    Ge, Dengteng; Yang, Lili; Wu, Gaoxiang; Yang, Shu

    2014-03-07

    Angle-independent coloured films with superhydrophobicity were fabricated from quasi-amorphous arrays of monodispersed fluorinated silica nanoparticles via one-step spray coating. The film exhibited a high contact angle (>150°) and a low roll-off angle (~2°) and the colour could be tuned to blue, green and moccasin by varying the size of the nanoparticles.

  3. Nitrogen cycle in microbial mats: completely unknown?

    Science.gov (United States)

    Coban, O.; Bebout, B.

    2015-12-01

    Microbial mats are thought to have originated around 3.7 billion years ago, most likely in the areas around submarine hydrothermal vents, which supplied a source of energy in the form of reduced chemical species from the Earth's interior. Active hydrothermal vents are also believed to exist on Jupiter's moon Europa, Saturn's moon Enceladus, and on Mars, earlier in that planet's history. Microbial mats have been an important force in the maintenance of Earth's ecosystems and the first photosynthesis was also originated there. Microbial mats are believed to exhibit most, if not all, biogeochemical processes that exist in aquatic ecosystems, due to the presence of different physiological groups of microorganisms therein. While most microbially mediated biogeochemical transformations have been shown to occur within microbial mats, the nitrogen cycle in the microbial mats has received very little study in spite of the fact that nitrogen usually limits growth in marine environments. We will present the first results in the determination of a complete nitrogen budget for a photosynthetic microbial mat. Both in situ sources and sinks of nitrogen in photosynthetic microbial mats are being measured using stable isotope techniques. Our work has a particular focus on recently described, but poorly understood, processes, e.g., anammox and dissimilatory nitrate reduction, and an emphasis on understanding the role that nitrogen cycling may play in generating biogenic nitrogen isotopic signatures and biomarker molecules. Measurements of environmental controls on nitrogen cycling should offer insight into the nature of co-evolution of these microbial communities and their planets of origin. Identifying the spatial (microscale) as well as temporal (diel and seasonal) distribution of nitrogen transformations, e.g., rates of nitrification and denitrification, within mats, particularly with respect to the distribution of photosynthetically-produced oxygen, is anticipated. The results

  4. A Nano-modified superhydrophobic membrane

    Energy Technology Data Exchange (ETDEWEB)

    Avila, Antonio Ferreira, E-mail: aavila@netuno.lcc.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Programa de Graduacao em Engenharia Mecania. Dept. de Engenharia Mecanica; Oliveira, Aline Marques de; Lacerda, Glenda Ribeiro de Barros Silveira; Munhoz, Viviane Cristina; Santos, Mayara Cele Goncalves; Santos, Patricia Figueiredo [Centro Federal de Educacao Tecnologica de Minas Gerais (CEFET-MG), Belo Horizonte, MG (Brazil). Programa de Quimica; Triplett, Matt [Aviation and Missile Research Development and Engineering Center, AMSRD-AMR-WD-GA, Redstone Arsenal, (United States)

    2013-11-01

    This paper focuses on the synthesis of super-hydrophobic membranes. The polymer used in this research is polystyrene (PS), which has low surface energy but not low enough to be characterized as a super hydrophobic material. As hydrophobicity is based on low energy surface and surface roughness, the electrospinning technique was selected as the manufacturing technique. N, N' dimethylformamide (DMF) was employed as the PS solvent. Two groups of PS/DMF solutions were investigated i.e. 20/80 and 35/65. To increase even more the hydrophobicity, nanoparticles of silica, graphene, cadmium, and zinc were dispersed into the PS/DMF solutions. In contrast to results previous published in literature, the PS/DMF weight ratio of 20/80 led to water contact angles (WCA) of 148 Degree-Sign , which is higher than the contact angle for the 35/65 ratio, i.e. 143 Degree-Sign . This fact seems to be due to the presence of non-evaporated solvent into the PS surface as the 35/65 solution was more viscous. The WCA for membranes with 0.5 wt. (%) of graphene reached 152 Degree-Sign , 149 Degree-Sign -153 Degree-Sign for membranes with nanosilica addition, 151 Degree-Sign with 5.0 wt. (%) CdS, and 153 Degree-Sign , 163 Degree-Sign and 168 Degree-Sign with the addition of 5 wt. (%), 10 wt. (%) and 15 wt. (%) of ZnS, respectively. author)

  5. Contact angle hysteresis on superhydrophobic stripes.

    Science.gov (United States)

    Dubov, Alexander L; Mourran, Ahmed; Möller, Martin; Vinogradova, Olga I

    2014-08-21

    We study experimentally and discuss quantitatively the contact angle hysteresis on striped superhydrophobic surfaces as a function of a solid fraction, ϕS. It is shown that the receding regime is determined by a longitudinal sliding motion of the deformed contact line. Despite an anisotropy of the texture the receding contact angle remains isotropic, i.e., is practically the same in the longitudinal and transverse directions. The cosine of the receding angle grows nonlinearly with ϕS. To interpret this we develop a theoretical model, which shows that the value of the receding angle depends both on weak defects at smooth solid areas and on the strong defects due to the elastic energy of the deformed contact line, which scales as ϕS(2)lnϕS. The advancing contact angle was found to be anisotropic, except in a dilute regime, and its value is shown to be determined by the rolling motion of the drop. The cosine of the longitudinal advancing angle depends linearly on ϕS, but a satisfactory fit to the data can only be provided if we generalize the Cassie equation to account for weak defects. The cosine of the transverse advancing angle is much smaller and is maximized at ϕS ≃ 0.5. An explanation of its value can be obtained if we invoke an additional energy due to strong defects in this direction, which is shown to be caused by the adhesion of the drop on solid sectors and is proportional to ϕS(2). Finally, the contact angle hysteresis is found to be quite large and generally anisotropic, but it becomes isotropic when ϕS ≤ 0.2.

  6. Superhydrophobic copper tubes with possible flow enhancement and drag reduction.

    Science.gov (United States)

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

    2009-06-01

    The transport of a Newtonian liquid through a smooth pipe or tube is dominated by the frictional drag on the liquid against the walls. The resistance to flow against a solid can, however, be reduced by introducing a layer of gas at or near the boundary between the solid and liquid. This can occur by the vaporization of liquid at a surface at a temperature above the Leidenfrost point, by a cushion of air (e.g. below a hovercraft), or by producing bubbles at the interface. These methods require a continuous energy input, but a more recent discovery is the possibility of using a superhydrophobic surface. Most reported research uses small sections of lithographically patterned surfaces and rarely considers pressure differences or varying flow rates. In this work we present a method for creating a uniform superhydrophobic nanoribbon layer on the inside of round copper tubes of millimetric internal radius. Two types of experiments are described, with the first involving a simultaneous comparison of four tubes with different surface finishes (as received, as received with hydrophobic coating, nanoribbon, and nanoribbon with a hydrophobic coating) under constant flow rate conditions using water and water-glycerol mixtures. The results show that the superhydrophobic nanoribbon with a hydrophobic coating surface finish allows greater flow at low pressure differences but that the effect disappears as the pressure at the inlet of the tube is increased. The second experiment is a simple visual demonstration of the low-pressure behavior using two nominally identical tubes in terms of length and cross-section, but with one tube possessing a superhydrophobic internal surface finish. In this experiment a reservoir is allowed to feed the two tubes with open ends via a T-piece and it is observed that, once flow commences, it preferentially occurs down the superhydrophobic tube.

  7. Solitary Fibrous Tumor of the Cerebello-Pontine Angle

    Science.gov (United States)

    Biggs, Nigel D.; Fagan, Paul A.; Turner, Jennifer J.; Doust, Bruce

    1999-01-01

    A case is presented of solitary fibrous tumor occurring in the cerebello-pontine angle. There have been only two other reported cases of a solitary fibrous tumors in this region. Imaging studies showed the tumor to be characteristic in shape and position of an acoustic tumor. However, at surgery the tumor was found to have a “rock hard” consistency. Solitary fibrous tumor differs from acoustic schwannoma and meningioma in its histopathological features and in this case, regrowth, after incomplete excision, was extremely rapid. ImagesFigure 2Figure 3Figure 4Figure 5Figure 6 PMID:17171119

  8. Fibrous Dysplasia versus Juvenile Ossifying Fibroma: A Dilemma.

    Science.gov (United States)

    Nair, Sreelakshmi N; Kini, Raghavendra; Rao, Prasanna Kumar; Bhandarkar, Gowri P; Kashyp, Roopashri Rajesh; Rai, Manjunath; Naik, Neel; Santhosh, Athul

    2016-01-01

    Fibrous dysplasia (FD) is a condition characterized by excessive proliferation of bone forming mesenchymal cells which can affect one bone (monostotic type) or multiple bones (polyostotic type). It is predominantly noticed in adolescents and young adults. Fibrous dysplasia affecting the jaws is an uncommon condition. The most commonly affected facial bone is the maxilla, with facial asymmetry being the chief complaint. The lesion in many instances is confused with ossifying fibroma (OF). Diagnosis of these two lesions has to be done based on clinical, radiographic, and microscopic findings. Here, we present a case of fibrous dysplasia of maxilla in a nine-year-old boy mimicking juvenile ossifying fibroma.

  9. Fibrous Dysplasia versus Juvenile Ossifying Fibroma: A Dilemma

    Science.gov (United States)

    Rao, Prasanna Kumar; Bhandarkar, Gowri P.; Rai, Manjunath; Naik, Neel; Santhosh, Athul

    2016-01-01

    Fibrous dysplasia (FD) is a condition characterized by excessive proliferation of bone forming mesenchymal cells which can affect one bone (monostotic type) or multiple bones (polyostotic type). It is predominantly noticed in adolescents and young adults. Fibrous dysplasia affecting the jaws is an uncommon condition. The most commonly affected facial bone is the maxilla, with facial asymmetry being the chief complaint. The lesion in many instances is confused with ossifying fibroma (OF). Diagnosis of these two lesions has to be done based on clinical, radiographic, and microscopic findings. Here, we present a case of fibrous dysplasia of maxilla in a nine-year-old boy mimicking juvenile ossifying fibroma. PMID:28101383

  10. A novel and expeditious method to fabricate superhydrophobic metal carboxylate surface

    Science.gov (United States)

    Li, Feng; Geng, Xingguo; Chen, Zhi; Zhao, Lei

    2012-01-01

    This article has presented a novel method to fabricate superhydrophobic metal carboxylate surface on substrates like copper, ferrum, etc. This method markedly shortened the fabrication time to less than one second. The superhydrophobic effect is even better that the contact angle (CA) is 170±1° and the sliding angle (SA) fatty acid and metal salt plays a key role in this method. This method has tremendous potentials in industrial production of superhydrophobic materials.

  11. Bacillamides from a hypersaline microbial mat bacterium.

    Science.gov (United States)

    Socha, Aaron M; Long, Richard A; Rowley, David C

    2007-11-01

    Chemical studies of a Bacillus endophyticus isolated from a Bahamian hypersaline microbial mat led to the isolation of bacillamides B and C, new tryptamide thiazole metabolites. Bioassay-guided fractionation using a HPLC-UV-MS bioassay technique enabled the detection of these trace fermentation products, and their total structures were elucidated by combined spectroscopic techniques.

  12. HiRadMat: materials under scrutiny

    CERN Multimedia

    Anaïs Schaeffer

    2011-01-01

    CERN's new facility, HiRadMat (High Radiation to Materials), which is designed to test materials for the world's future particle accelerators, should be operational and welcoming its first experiments by the end of the year.   The HiRadMat facility, located in the TNC tunnel. The materials used in the LHC and its experiments are exposed to very high-energy particles. The LHC machine experts obviously didn't wait for the first collisions in the world's most powerful accelerator to put the materials through their paces - the equipment was validated following a series of stringent tests. And these tests will get even tougher now, with the arrival of HiRadMat. The tunnel that formerly housed the West Area Neutrino Facility (WANF) has been completely revamped to make way for CERN's latest facility, HiRadMat. Supported by the Radioprotection service, a team from the Engineering (EN) Department handled the dismantling operations from October 2009 to December 2010. "We could only work on disman...

  13. When to Go to the Mat

    Science.gov (United States)

    Smith, Carol A.

    2017-01-01

    School leaders rightly tend toward collaboration and consensus-building when it comes to important decisions affecting students. But there are moments when, perhaps to their own surprise, they may find themselves willing to "go to the mat" on an important decision, whether consensus has been reached or not. Smith, a professor and chair…

  14. Electromagnetic shielding mats: facts and fiction.

    Science.gov (United States)

    Leitgeb, N; Cech, R

    2007-01-01

    The use of electricity is accompanied by electric and magnetic fields which, intended or not, became a part of our environment. However, fear from environmental electromagnetic fields (EMFs) is widespread and so is business with fear. A number of more or less serious products including miracle products are placed on the market partly at excessive costs. By numerical simulation the efficiency of electromagnetic shielding mats was investigated and claims of manufacturers and their cited expert opinions checked. It could be shown that such products do not fulfil the justified expectations of customers, neither in the extremely low frequency (ELF) nor in the radiofrequency (RF) range. On the contrary, these mats usually make things even worse. The connection to ground, if available, might increase the belief on shielding efficiency, but in fact it even enhances fields instead of improving shielding. The electric conductivity of the mat material plays a minor role in the ELF range and enhances field increase in the RF range. It can not explain the enormous price differences. It could be shown that positive reports can be explained by result picking and exceptional arrangements of selected field sources. Overall, the investigation showed that manufacturer's claims about the shielding effectiveness are misleading and fool the customers about the real situation. Therefore, acquisition and use of electromagnetic shielding mats must be strongly discouraged.

  15. Current trend in fabrication of complex morphologically tunable superhydrophobic nano scale surfaces

    Science.gov (United States)

    Abdulhussein, Ali T.; Kannarpady, Ganesh K.; Wright, Andrew B.; Ghosh, Anindya; Biris, Alexandru S.

    2016-10-01

    Superhydrophobic surfaces are found in nature and possess several fascinating properties, including the ability to self-clean. A typical superhydrophobic surface has micro/nanostructure roughness and low surface energy, which combine to give it its unusual anti-wetting properties. Because of their unique capabilities, these surfaces have interested scientists in research and industry fields for years. In recent decades, researchers have developed a number of synthetic methods for producing novel superhydrophobic surfaces that mimic natural surfaces. These synthetic surfaces have been widely applied on different types of substrates for potential widespread, practical applications. This review article focuses on these advances in fabricating manmade superhydrophobic surfaces.

  16. Thermodynamics and phase transformations the selected works of Mats Hillert

    CERN Document Server

    Lilensten, Jean

    2006-01-01

    This book is a compendium of Mat Hillert's publications. Mat Hillert is a world specialist in metal alloy at the origin of a universal computing code used to calculate the diagrams of phase. This work is in English.

  17. Solitary fibrous tumor of the pleura.

    Science.gov (United States)

    Marak, Creticus P; Dorokhova, Olena; Guddati, Achuta K

    2013-01-01

    Solitary fibrous tumor of the pleura (SFTP) is a rare tumor of mesenchymal origin which can grow to a large size and present with symptoms of cough and pleuritic chest pain. No specific etiological factors for SFTPs are known and they may grow undetected for several years. These tumors are usually benign and may mimic a variety of malignancies. SFTPs are often detected as peripheral opacities on chest X-ray. Unfortunately, fine needle aspiration rarely provides adequate information for a definitive diagnosis. Imaging with computed tomography provides details about the size and extent of any invasion into adjacent tissues. Surgical resection is the mainstay of treatment, and immunohistochemistry of the resected tumor often provides confirmation of the diagnosis. Some SFTPs have been observed to be malignant, and surgical intervention is often lifesaving. There is no adequate data to support the usage of radiotherapy and chemotherapy in the treatment of SFTPs. This tumor exemplifies malignancies which require surgical resection to preempt worse outcomes. Awareness of their presentation and clinical course may help the clinician provide a prompt referral to the thoracic surgeon for resection.

  18. Treating Fibrous Insulation to Reduce Thermal Conductivity

    Science.gov (United States)

    Zinn, Alfred; Tarkanian, Ryan

    2009-01-01

    A chemical treatment reduces the convective and radiative contributions to the effective thermal conductivity of porous fibrous thermal-insulation tile. The net effect of the treatment is to coat the surfaces of fibers with a mixture of transition-metal oxides (TMOs) without filling the pores. The TMO coats reduce the cross-sectional areas available for convection while absorbing and scattering thermal radiation in the pores, thereby rendering the tile largely opaque to thermal radiation. The treatment involves a sol-gel process: A solution containing a mixture of transition-metal-oxide-precursor salts plus a gelling agent (e.g., tetraethylorthosilicate) is partially cured, then, before it visibly gels, is used to impregnate the tile. The solution in the tile is gelled, then dried, and then the tile is fired to convert the precursor salts to the desired mixed TMO phases. The amounts of the various TMOs ultimately incorporated into the tile can be tailored via the concentrations of salts in the solution, and the impregnation depth can be tailored via the viscosity of the solution and/or the volume of the solution relative to that of the tile. The amounts of the TMOs determine the absorption and scattering spectra.

  19. [Malignant fibrous histiocytoma of the penis].

    Science.gov (United States)

    Crisman, G; Margiotta, G; Calabresi, M; Discepoli, S; Leocata, P

    2015-07-01

    According to the most recent World Health Organization (WHO) guidelines a diagnosis of malignant fibrous histiocytoma (MFH) should be made only for lesions composed of tumor cells without evidence of a specific line of differentiation. This is therefore a diagnosis by exclusion which is why the name of undifferentiated high-grade pleomorphic sarcoma (UPS) should be preferred. Soft tissue sarcomas currently have an incidence in all body regions of approximately 20 cases per 1 million inhabitants per year. Soft tissue tumors of the penis represent approximately 5 % of all penile tumors and the incidence of penile sarcomas is estimated to be approximately 0.6-1 case per 100,000 patients. Only seven cases have so far been reported in the literature. This article describes the case of a 61-year-old Caucasian male who presented with a painless mass sited in the upper part of the corpus cavernosa. An incisional biopsy with a subsequent investigation using an extensive immunohistochemical panel were performed and a high-grade undifferentiated pleomorphic sarcoma or pleomorphic storiform MFH was diagnosed. In addition to the case report a literature review is presented to elaborate the discussion on the differential diagnoses of these kinds of lesions.

  20. Intracranial solitary fibrous tumor: Imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Clarencon, Frederic, E-mail: fredclare5@msn.com [Department of Neuroradiology, Pitie-Salpetriere Hospital, APHP, 75013 Paris (France); Bonneville, Fabrice [Department of Neuroradiology, Hopital Rangueil, Toulouse University Hospital, 31000 Toulouse (France); Rousseau, Audrey [Department of Neuropathology, Pitie-Salpetriere Hospital (France); Galanaud, Damien [Department of Neuroradiology, Pitie-Salpetriere Hospital, APHP, 75013 Paris (France); Kujas, Michele [Department of Neuropathology, Pitie-Salpetriere Hospital (France); Naggara, Olivier [Department of Neuroradiology, St Anne Hospital, 75014 Paris (France); Cornu, Philippe [Department of Neurosurgery, Pitie-Salpetriere Hospital (France); Chiras, Jacques [Department of Neuroradiology, Pitie-Salpetriere Hospital, APHP, 75013 Paris (France)

    2011-11-15

    Objective: To study the neuroimaging features of intracranial solitary fibrous tumors (ISFTs). Materials and methods: Retrospective study of neuroimaging features of 9 consecutive histopathologically proven ISFT cases. Location, size, shape, density, signal intensity and gadolinium uptake were studied at CT and MRI. Data collected from diffusion-weighted imaging (DWI) (3 patients), perfusion imaging and MR spectroscopy (2 patients), and DSA (4 patients) were also analyzed. Results: The tumors most frequently arose from the intracranial meninges (7/9), while the other lesions were intraventricular. Tumor size ranged from 2.5 to 10 cm (mean = 6.6 cm). They presented multilobular shape in 6/9 patients. Most ISFTs were heterogeneous (7/9) with areas of low T2 signal intensity that strongly enhanced after gadolinium administration (6/8). Erosion of the skull was present in about half of the cases (4/9). Components with decreased apparent diffusion coefficient were seen in 2/3 ISFTs on DWI. Spectroscopy revealed elevated peaks of choline and myo-inositol. MR perfusion showed features of hyperperfusion. Conclusion: ISFT should be considered in cases of extra-axial, supratentorial, heterogeneous, hypervascular tumor. Areas of low T2 signal intensity that strongly enhance after gadolinium injection are suggestive of this diagnosis. Restricted diffusion and elevated peak of myo-inositol may be additional valuable features.

  1. Reflective Coating on Fibrous Insulation for Reduced Heat Transfer

    Science.gov (United States)

    Hass, Derek D.; Prasad, B. Durga; Glass, David E.; Wiedemann, Karl E.

    1997-01-01

    Radiative heat transfer through fibrous insulation used in thermal protection systems (TPS) is significant at high temperatures (1200 C). Decreasing the radiative heat transfer through the fibrous insulation can thus have a major impact on the insulating ability of the TPS. Reflective coatings applied directly to the individual fibers in fibrous insulation should decrease the radiative heat transfer leading to an insulation with decreased effective thermal conductivity. Coatings with high infrared reflectance have been developed using sol-gel techniques. Using this technique, uniform coatings can be applied to fibrous insulation without an appreciable increase in insulation weight or density. Scanning electron microscopy, Fourier Transform infrared spectroscopy, and ellipsometry have been performed to evaluate coating performance.

  2. Fabrication of highly modulable fibrous 3D extracellular microenvironments

    KAUST Repository

    Zhang, Xixiang

    2017-06-13

    Three-dimensional (3D) in vitro scaffolds that mimic the irregular fibrous structures of in vivo extracellular matrix (ECM) are critical for many important biological applications. However, structural properties modulation of fibrous 3D scaffolds remains a challenge. Here, we report the first highly modulable 3D fibrous scaffolds self-assembled by high-aspect-ratio (HAR) microfibers. The scaffolds structural properties can be easily tailored to incorporate various physical cues, including geometry, stiffness, heterogeneity and nanotopography. Moreover, the fibrous scaffolds are readily and accurately patterned on desired locations of the substrate. Cell culture exhibits that our scaffolds can elicit strong bidirectional cell-material interactions. Furthermore, a functional disparity between the two-dimensional substrate and our 3D scaffolds is identified by cell spreading and proliferation data. These results prove the potential of the proposed scaffold as a biomimetic extracellular microenvironment for cell study.

  3. General Information about Osteosarcoma and Malignant Fibrous Histiocytoma of Bone

    Science.gov (United States)

    ... to the lung. Bone Metastasis or Bone with Lung Metastasis Osteosarcoma and malignant fibrous histiocytoma may spread to a distant bone and/or the lung. Treatment may include the following: Combination chemotherapy followed ...

  4. Treatment Option Overview (Osteosarcoma and Malignant Fibrous Histiocytoma of Bone)

    Science.gov (United States)

    ... to the lung. Bone Metastasis or Bone with Lung Metastasis Osteosarcoma and malignant fibrous histiocytoma may spread to a distant bone and/or the lung. Treatment may include the following: Combination chemotherapy followed ...

  5. MRI of fibrous cortical defect and non-ossifying fibroma

    Energy Technology Data Exchange (ETDEWEB)

    Mishima, Yoshiko; Aoki, Takatoshi; Watanabe, Hideyuki; Nakata, Hajime; Hashimoto, Hiroshi; Nakamura, Toshitaka [Univ. of Occupational and Environmental Health, Kitakyushu, Fukuoka (Japan). School of Medicine

    1999-02-01

    Fibrous cortical defect and non-ossifying fibroma are the benign fibrous lesions of bone commonly involving children. Their diagnosis is usually done with radiography, and MR examinations are rarely performed. We evaluated MRI findings of 11 lesions in 10 cases of fibrous cortical defect and non-ossifying fibroma. Signal intensity of the lesions was varied and large lesions (2 cm<) tended to show heterogeneous signal intensity on both T1-weighted and T2-weighted images corresponding to a mixture of components including fibrous tissue, hemosiderin and foam cells. MRI helps to delineate the extent of the involved bone and to assess the various histological components of the lesions. However, their diagnosis is basically made on the radiographic findings and the role of MRI is limited. (author)

  6. Ehlers-Danlos syndrome with monostotic fibrous dysplasia

    Directory of Open Access Journals (Sweden)

    Rao A

    1979-01-01

    Full Text Available An unusual case of Ehlers-Danlos syndrome with monostotic fibrous dysplasia of the humorus is presented. The other orthopae-dic manifestations, its complications and associated features are re-viewed and summarised.

  7. Method for production of carbon nanofiber mat or carbon paper

    Science.gov (United States)

    Naskar, Amit K.

    2015-08-04

    Method for the preparation of a non-woven mat or paper made of carbon fibers, the method comprising carbonizing a non-woven mat or paper preform (precursor) comprised of a plurality of bonded sulfonated polyolefin fibers to produce said non-woven mat or paper made of carbon fibers. The preforms and resulting non-woven mat or paper made of carbon fiber, as well as articles and devices containing them, and methods for their use, are also described.

  8. Method for production of carbon nanofiber mat or carbon paper

    Energy Technology Data Exchange (ETDEWEB)

    Naskar, Amit K.

    2015-08-04

    Method for the preparation of a non-woven mat or paper made of carbon fibers, the method comprising carbonizing a non-woven mat or paper preform (precursor) comprised of a plurality of bonded sulfonated polyolefin fibers to produce said non-woven mat or paper made of carbon fibers. The preforms and resulting non-woven mat or paper made of carbon fiber, as well as articles and devices containing them, and methods for their use, are also described.

  9. Fibrous epulis associated with impacted lower right third molar

    Directory of Open Access Journals (Sweden)

    Ni Putu Mira Sumarta

    2009-12-01

    Full Text Available Background: Epulis or epulides are lesions associated with gingival tissues. Fibrous epulis is a type of hyperplastic fibrous tissue mass located at the gingival which is slow growing, painless, having same color as the oral mucosa and firm on palpation. Anterior regions of the oral cavity are the frequently affected sites as these areas are more prone to be affected by calculus deposition and poor plaque control due to frequent teeth malposition. Removal of any irritating factors and excision of the lesion are the usual treatments. Purpose: This case report presents a rare case of fibrous epulis which occurred in the posterior region of the oral cavity and associated with impacted lower third molar. Case: A case of fibrous epulis at the lower right third molar area of three months duration is presented. The mass was slow growing, painless and on examination it was a pedunculated mass overlying the unerupted lower right third molar, having same color with the oral mucosa and firm on palpation. Clinically, the lesion was diagnosed as fibrous epulis associated with impacted lower right third molar. Case management: The treatment were surgical excision of the epulis and removal of the lower right third molar. The histopathology result showed tissue with squamous epithelial lining, achanthotic fibrous connective tissue, mononuclear inflammatory cells and few capillaries without signs of malignancy. This is consistent with the diagnosis of fibrous epulis. Conclusion: Fibrous epulis, although frequently occurred at the anterior region of the oral cavity, may rarely grow at the area of lower third molar. This phenomenon supports the theory that epulis can grow on any surface of oral mucous membrane as long as local irritants are present.

  10. Superhydrophobic Surface Coatings for Microfluidics and MEMs.

    Energy Technology Data Exchange (ETDEWEB)

    Branson, Eric D.; Singh, Seema [Sandia National Laboratories, Livermore, CA; Houston, Jack E.; van Swol, Frank B.; Brinker, C. Jeffrey

    2006-11-01

    Low solid interfacial energy and fractally rough surface topography confer to Lotus plants superhydrophobic (SH) properties like high contact angles, rolling and bouncing of liquid droplets, and self-cleaning of particle contaminants. This project exploits the porous fractal structure of a novel, synthetic SH surface for aerosol collection, its self-cleaning properties for particle concentration, and its slippery nature 3 to enhance the performance of fluidic and MEMS devices. We propose to understand fundamentally the conditions needed to cause liquid droplets to roll rather than flow/slide on a surface and how this %22rolling transition%22 influences the boundary condition describing fluid flow in a pipe or micro-channel. Rolling of droplets is important for aerosol collection strategies because it allows trapped particles to be concentrated and transported in liquid droplets with no need for a pre-defined/micromachined fluidic architecture. The fluid/solid boundary condition is important because it governs flow resistance and rheology and establishes the fluid velocity profile. Although many research groups are exploring SH surfaces, our team is the first to unambiguously determine their effects on fluid flow and rheology. SH surfaces could impact all future SNL designs of collectors, fluidic devices, MEMS, and NEMS. Interfaced with inertial focusing aerosol collectors, SH surfaces would allow size-specific particle populations to be collected, concentrated, and transported to a fluidic interface without loss. In microfluidic systems, we expect to reduce the energy/power required to pump fluids and actuate MEMS. Plug-like (rather than parabolic) velocity profiles can greatly improve resolution of chip-based separations and enable unprecedented control of concentration profiles and residence times in fluidic-based micro-reactors. Patterned SH/hydrophilic channels could induce mixing in microchannels and enable development of microflow control elements

  11. Disruption of photoautotrophic intertidal mats by filamentous fungi

    DEFF Research Database (Denmark)

    Carreira, Cátia; Staal, Marc Jaap; Falkoski, Daniel

    2015-01-01

    Summary: Ring-like structures, 2.0-4.8cm in diameter, observed in photosynthetic microbial mats on the Wadden Sea island Schiermonnikoog (the Netherlands) showed to be the result of the fungus Emericellopsis sp. degrading the photoautotrophic top layer of the mat. The mats were predominantly comp...

  12. Disruption of photoautotrophic intertidal mats by filamentous fungi

    NARCIS (Netherlands)

    Carreira, C.; Staal, M.; Falkoski, D; de Vries, R.P.; Middelboe, M.; Brussaard, C.P.D.

    2015-01-01

    Ring-like structures, 2.0-4.8 cm in diameter, observed in photosynthetic microbial mats on the Wadden Sea island Schiermonnikoog (the Netherlands) showed to be the result of the fungus Emericellopsis sp. degrading the photoautotrophic top layer of the mat. The mats were predominantly composed of cya

  13. Disruption of photoautotrophic intertidal mats by filamentous fungi

    NARCIS (Netherlands)

    Carreira, Cátia; Staal, Marc; Falkoski, Daniel; De Vries, Ronald P.; Middelboe, Mathias; Brussaard, Corina P D

    2015-01-01

    Ring-like structures, 2.0-4.8cm in diameter, observed in photosynthetic microbial mats on the Wadden Sea island Schiermonnikoog (the Netherlands) showed to be the result of the fungus Emericellopsis sp. degrading the photoautotrophic top layer of the mat. The mats were predominantly composed of cyan

  14. Disruption of photoautotrophic intertidal mats by filamentous fungi

    NARCIS (Netherlands)

    Carreira, C; Staal, M.; Falkoski, D.; de Vries, R.P.; Middelboe, M.; Brussaard, C.P.D.

    2015-01-01

    Ring-like structures, 2.0–4.8?cm in diameter, observed in photosynthetic microbial mats on the Wadden Sea island Schiermonnikoog (the Netherlands) showed to be the result of the fungus Emericellopsis sp. degrading the photoautotrophic top layer of the mat. The mats were predominantly composed of cya

  15. Beaded Fiber Mats of PVA Containing Unsaturated Heteropoly Salt

    Institute of Scientific and Technical Information of China (English)

    Guo Cheng YANG; Yan PAN; Jian GONG; Chang Lu SHAO; Shang Bin WEN; Chen SHAO; Lun Yu QU

    2004-01-01

    Poly(vinyl alcohol) (PVA) fiber mats containing unsaturated heteropoly salt was prepared for the first time. IR, X-ray diffraction and SEM photographs characterized the beaded fiber mats.The viscoelasticity and the conductivity of the solution were the key factors that influence the formation of the beaded fiber mats.

  16. Simulation and Analysis of Unbonded Nonwoven Fibrous Structures

    Directory of Open Access Journals (Sweden)

    Behnam Pourdeyhimi

    2006-11-01

    Full Text Available In this work we report on our algorithm for generating 3-D virtual structures resembling un-bonded fibrous webs. The paper discusses short and infinitely long fibers, each emulating a category of nonwoven fibrous medium. The structure Solid Volume Fraction (SVF, being the most important characteristic of a fibrous porous medium, is calculated for different fiberwebs and discussed in details. It is shown that the SVF of the fibrous structures generated by our algorithm is independent of the basis weight. In other words, the porosity of the medium is only a function of the fiber properties – this is as expected. It is also demonstrated that by decreasing the fiber diameter while keeping other properties of the virtual fiberweb constant causes the SVF to decrease almost linearly. The same is not observed for the fiber rigidity. The capability of our algorithm for generating fibrous webs made up of layers of different fibers is demonstrated and their properties are discussed. The application of such virtual fibrous structures in modeling transport phenomena in nonwoven materials and their potential applications in load-deformation studies are discussed.

  17. The usefulness of nucleomedical procedures in diagnosis of fibrous dysplasia

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, Nobuaki; Fukunaga, Masao; Ono, Shimato (Kawasaki Medical School, Kurashiki, Okayama (Japan)) (and others)

    1989-09-01

    Bone scintigraphy with {sup 99m}Tc-phosphorous compounds and {sup 67}Ga scintigraphy were performed in 8 patients (monostotic 3 cases, polyostotic 5 cases) with fibrous dysplasia. The tendency toward abnormal accumulation of radioactivity on bone scintigraphy was high in the tibia, maxilla, mandibule and ribs. The characteristics of the scintigraphic image at the sites of bone lesion in fibrous dysplasia were judged to be marked (++), moderate (+) or poor or minimal (-), according to the degree of accumulation of radioactivity. Eleven sites of fibrous dysplasia showed marked accumulation and 5 sites showed moderate accumulation. Poor or minimal accumulation was not observed in any fibrous dysplasia lesions. Sclerotic changes on bone roentgenograms appeared as marked accumulation of radionuclides on bone scintigraphy in all cases. Cystic changes on roentgenograms showed a tendency toward moderate accumulation on scintigrams. {sup 67}Ga scans were also all positive for 2 experimental cases (3 sites) of bone lesions of fibrous dysplasia. Thus, bone and {sup 67}Ga scintigraphies appear to be useful and essential in evaluating the pathophysiology of fibrous dysplasia. (author).

  18. Studies of drag on the nanocomposite superhydrophobic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Brassard, Jean-Denis [Anti-icing Materials International Laboratory (AMIL), Université du Québec à Chicoutimi, 555 Boulevard de l‘Université, Chicoutimi, Québec, Canada G7H 2B1 (Canada); Centre Universitaire de Recherche sur l’Aluminium (CURAL), Université du Québec à Chicoutimi, 555 Boulevard de l‘Université, Chicoutimi, Québec, Canada G7H 2B1 (Canada); Sarkar, D.K., E-mail: dsarkar@uqac.ca [Centre Universitaire de Recherche sur l’Aluminium (CURAL), Université du Québec à Chicoutimi, 555 Boulevard de l‘Université, Chicoutimi, Québec, Canada G7H 2B1 (Canada); Perron, Jean [Anti-icing Materials International Laboratory (AMIL), Université du Québec à Chicoutimi, 555 Boulevard de l‘Université, Chicoutimi, Québec, Canada G7H 2B1 (Canada)

    2015-01-01

    Graphical abstract: - Highlights: • The nanocomposite thin films of stearic acid (SA)-functionalized ZnO nanoparticles incorporated in epoxy polymer matrix have been achieved. • SA-functionalization of ZnO nanoparticles in the thin films was confirmed by XRD and FTIR. • The measured rms roughness of the thin film is found to be 12 ± 1 μm with the adhesion of 5B on glass. • The wetting property shows that the surface of the film is superhydrophobic with the CA of 156 ± 4° and CAH of 4 ± 2°. • The drag reduction on the surface of superhydrophobic glass sphere is 16% lower than as-received glass sphere. - Abstract: The nanocomposite thin films of stearic acid (SA)-functionalized ZnO nanoparticles incorporated in epoxy polymer matrix have been achieved. The X-ray diffraction (XRD) studies show the formation of zinc stearate on ZnO nanoparticles as the confirmation of SA-functionalization of ZnO nanoparticles in the thin films. Morphological analyses reveal the presence of micro-holes with the presence of irregular nanoparticles. The measured root mean square (rms) roughness of the thin film is found to be 12 ± 1 μm with the adhesion of 5B on both glass and aluminum substrates. The wetting property shows that the surface of the film is superhydrophobic with the contact angle of water of 156 ± 4° having contact angle hysteresis (CAH) of 4 ± 2°. The average terminal velocity in the water of the as-received glass spheres and superhydrophobic spheres were found to be 0.66 ± 0.01 m/s and 0.72 ± 0.01 m/s respectively. Consequently, the calculated average coefficients of the surface drag of the as-received glass sphere and superhydrophobic glass sphere were 2.30 ± 0.01 and 1.93 ± 0.03, respectively. Hence, the drag reduction on the surface of superhydrophobic glass sphere is found to be approximately 16% lower than as-received glass sphere.

  19. Control and optimization of Clostridium tyrobutyricum ATCC 25755 adhesion into fibrous matrix in a fibrous bed bioreactor.

    Science.gov (United States)

    Jiang, Ling; Wang, Jufang; Liang, Shizhong; Cai, Jin; Xu, Zhinan

    2011-09-01

    The great performance of a fibrous bed bioreactor (FBB) is mainly dependent on the cell adhesion and immobilization into the fibrous matrix. Therefore, understanding the mechanism and factors controling cell adhesion in the fibrous matrix is necessary to optimize the FBB setup and further improve the fermentability. The adhesion behavior of a strain of Clostridium tyrobutyricum isolated from an FBB was studied, which was proven to be affected by the different environmental conditions, such as growth phase of cells, pH, ionic strength, ionic species, and composition of media. Our results also suggested that electrostatic interactions played an important role on bacteria adhesion into the fibrous matrix. This study demonstrated that the compositions of fermentation broth would have a significant effect on cell adhesion. Consequently, a two-stage glucose supply control strategy was developed to improve the performance of FBB with higher viable cell density in the operation of the FBB setup.

  20. Contributions of ectomycorrhizal fungal mats to forest soil respiration

    Directory of Open Access Journals (Sweden)

    C. L. Phillips

    2012-02-01

    Full Text Available Distinct aggregations of fungal hyphae and rhizomorphs, or "mats" formed by some genera of ectomycorrhizal (EcM fungi are common features of soils in coniferous forests of the Pacific Northwest. We measured in situ respiration rates of Piloderma mats and neighboring non-mat soils in an old-growth Douglas-fir forest in Western Oregon to investigate whether there was an incremental increase in respiration from mat soils, and to estimate mat contributions to total soil respiration. We found that areas where Piloderma mats colonized the organic horizon often had higher soil surface flux than non-mats, with the incremental increase in respiration averaging 16 % across two growing seasons. Both soil physical factors and biochemistry were related to the higher surface flux of mat soils. When air-filled pore space was low (high soil moisture, soil CO2 production was concentrated into near-surface soil horizons where mats tend to colonize, resulting in greater apparent differences in respiration between mat and non-mat soils. Respiration rates were also correlated with the activity of chitin-degrading soil enzymes. This suggests that the elevated activity of fungal mats may be related to consumption or turnover of chitinous fungal cell-wall materials. We found Piloderma mats present across 57 % of the soil surface in the study area, and use this value to estimate a respiratory contribution from mats at the stand-scale of about 9 % of total soil respiration. The activity of EcM mats, which includes both EcM fungi and microbial associates, was estimated to constitute a substantial portion of total soil respiration in this old-growth Douglas-fir forest.

  1. Clinicopathological analysis of solitary fibrous tumor

    Institute of Scientific and Technical Information of China (English)

    Xiumei Zhang; Hai Wang; Shujing Wang; Jinfeng Miao; Zhengai Piao; Yingying Dong

    2012-01-01

    Objective: The aim of this study was to investigate the clinicopathologic characteristics, diagnosis and differential diagnosis, molecular genetics, treatment and prognosis of solitary fibrous tumor (SFT). Methods: The clinicopathological manifestations were analyzed retrospectively in 22 patients with surgically confirmed SFT. Results: There were 12 male patients and 10 female patients, with the age range 33–67 (mean 48.62) years. The SFTs originated from different from parts of the body, including 13 in the chest, 2 in the lungs, 3 in the abdomen, 1 in the lumbosacral area, 2 in the pelvis, and 1 in the left shoulder. There were 19 benign and 3 malignant tumors. Major clinical presentations were local masses and compression symptoms. Microscopy: the tumor was composed of areas of alternating hypercellularity and hypocellularity. The tumor cells were spindle to short-spindle shaped and arranged in fascicular or storiform pattern and hemangiopericytoma-like structure was presented. Immunohistochemically, Vimentin positive rate was 100% (22/22), Bcl-2 positive rate was 95.5% (21/22), CD99 positive rate was 86.4% (19/22), CD34 positive rate was 81.8 (18/22), focally positive for P53, as well as negative CK, S100 and Desmin. Ki67 labelling index was 2%–30%. Conclusion: SFT is a rare tumor which may be found in various parts of human body. SFT mostly is a benign tumor, but a few could be malignant. Its diagnosis mainly rely on its morphologic features and immunohistochemical profiles. The major treatment is to completely resect it by operation and long-term clinical follow-up is necessary.

  2. Gene expression profiling of solitary fibrous tumors.

    Directory of Open Access Journals (Sweden)

    François Bertucci

    Full Text Available BACKGROUND: Solitary fibrous tumors (SFTs are rare spindle-cell tumors. Their cell-of-origin and molecular basis are poorly known. They raise several clinical problems. Differential diagnosis may be difficult, prognosis is poorly apprehended by histoclinical features, and no effective therapy exists for advanced stages. METHODS: We profiled 16 SFT samples using whole-genome DNA microarrays and analyzed their expression profiles with publicly available profiles of 36 additional SFTs and 212 soft tissue sarcomas (STSs. Immunohistochemistry was applied to validate the expression of some discriminating genes. RESULTS: SFTs displayed whole-genome expression profiles more homogeneous and different from STSs, but closer to genetically-simple than genetically-complex STSs. The SFTs/STSs comparison identified a high percentage (∼30% of genes as differentially expressed, most of them without any DNA copy number alteration. One of the genes most overexpressed in SFTs encoded the ALDH1 stem cell marker. Several upregulated genes and associated ontologies were also related to progenitor/stem cells. SFTs also overexpressed genes encoding therapeutic targets such as kinases (EGFR, ERBB2, FGFR1, JAK2, histone deacetylases, or retinoic acid receptors. Their overexpression was found in all SFTs, regardless the anatomical location. Finally, we identified a 31-gene signature associated with the mitotic count, containing many genes related to cell cycle/mitosis, including AURKA. CONCLUSION: We established a robust repertoire of genes differentially expressed in SFTs. Certain overexpressed genes could provide new diagnostic (ALDH1A1, prognostic (AURKA and/or therapeutic targets.

  3. Mudd's disease (MAT I/III deficiency) : a survey of data for MAT1A homozygotes and compound heterozygotes

    NARCIS (Netherlands)

    Chien, Yin-Hsiu; Abdenur, Jose E.; Baronio, Federico; Bannick, Allison Anne; Corrales, Fernando; Couce, Maria; Donner, Markus G.; Ficicioglu, Can; Freehauf, Cynthia; Frithiof, Deborah; Gotway, Garrett; Hirabayashi, Koichi; Hofstede, FC; Hoganson, George; Hwu, Wuh-Liang; James, Philip; Kim, Sook; Korman, Stanley H.; Lachmann, Robin; Levy, Harvey; Lindner, Martin; Lykopoulou, Lilia; Mayatepek, Ertan; Muntau, Ania; Okano, Yoshiyuki; Raymond, Kimiyo; Rubio-Gozalbo, Estela; Scholl-Buergi, Sabine; Schulze, Andreas; Singh, Rani; Stabler, Sally; Stuy, Mary; Thomas, Janet; Wagner, Conrad; Wilson, William G.; Wortmann, Saskia; Yamamoto, Shigenori; Pao, Maryland; Blom, Henk J.; Hofstede, FC

    2015-01-01

    Background: This paper summarizes the results of a group effort to bring together the worldwide available data on patients who are either homozygotes or compound heterozygotes for mutations in MAT1A. MAT1A encodes the subunit that forms two methionine adenosyltransferase isoenzymes, tetrameric MAT I

  4. Inhibitory effect of super-hydrophobicity on silver release and antibacterial properties of super-hydrophobic Ag/TiO2 nanotubes.

    Science.gov (United States)

    Zhang, Licheng; Zhang, Lihai; Yang, Yun; Zhang, Wei; Lv, Houchen; Yang, Fei; Lin, Changjian; Tang, Peifu

    2016-07-01

    The antibacterial properties of super-hydrophobic silver (Ag) on implant surface have not yet to be fully illuminated. In our study, we investigate the protective effects of super-hydrophobic coating of silver/titanium dioxide (Ag/TiO2 ) nanotubes against bacterial pathogens, as well as its pattern of Ag release. Ag/TiO2 nanotubes are prepared by a combination of electrochemical anodization and pulse electrodeposition. The super-hydrophobic coating is prepared by modifying the surface of Ag/TiO2 nanotubes with 1H, 1H, 2H, 2H-perfluorooctyl-triethoxysilane (PTES). Surface features and Ag release are examined by SEM, X-ray photoelectron spectroscopy, contact-angle measurement, and inductively coupled plasma-mass spectrometry (ICP-MS). The antibacterial activity of super-hydrophobic coating Ag/TiO2 nanotubes is investigated both in vitro and in vivo. Consequently, the super-hydrophobic coating on Ag/TiO2 nanotubes shows a regularly arranged structure; and nano-Ag particles (10-30 nm) are evenly distributed on the surface or inside the nanotubes. The contact angles of water on the super-hydrophobic coating Ag/TiO2 nanotubes are all above 150°. In addition, the super-hydrophobic character displays a certain conserved effect that contributes to the sustained release of Ag. The super-hydrophobic Ag/TiO2 nanotubes are also effective in inhibiting bacterial adhesion, killing the adhering bacteria and preventing postoperative infection in rabbits. Therefore, it is expected that the super-hydrophobic Ag/TiO2 nanotubes which can contain the release of Ag, leading to stable release, may show a consistent surface antibacterial capability. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1004-1012, 2016.

  5. A call to expand regulation to all carcinogenic fibrous minerals

    Science.gov (United States)

    Baumann, F.; Steele, I.; Ambrosi, J.; Carbone, M.

    2013-05-01

    The regulatory term "asbestos" groups only the six fibrous minerals that were commercially used among approximately 400. The carcinogenicity of these six regulated minerals has been largely demonstrated and is related to fiber structure, fiber length/diameter ratio, and bio-persistence. From a public perception, the generic term "asbestos" refers to the fibrous minerals that cause asbestosis, mesothelioma and other cancers. However, other non-regulated fibrous minerals are potentially as dangerous as the regulatory asbestos because they share similar physical and chemical properties, epidemiological studies have demonstrated their relationship with asbestos-related diseases, and both in vitro and in vivo experiments have established the toxicity of these minerals. For example, the non-regulated asbestiform winchite and richterite minerals that contaminated the vermiculite mined from Libby, Montana, (USA) were associated with mesothelioma, lung cancer and asbestosis observed among the area's residents and miners. Many other examples of non-regulated carcinogenic fibrous minerals include, but are not limited to, antigorite, arfvedsonite, balangeroite, carlosturanite, erionite, fluoro-edenite, hornblende, mordenite, palygorskite, and sepiolite. To propose a regulatory definition that would provide protection from all carcinogenic fibers, we have conducted an interdisciplinary literature review to compare the characteristics of "asbestos" and of non-regulated mineral fibers that relate to carcinogenicity. We specifically studied two non-regulated fibrous minerals that are associated with asbestos-related diseases: the serpentine antigorite and the zeolite erionite. Both examples underscore the problem of regulation based on commercial, rather than scientific principles: 1) the occurrence of fibrous antigorite in materials used to pave roads has been correlated with high mesothelioma rates in New Caledonia. Antigorite was also the cause of asbestosis in Poland, and in

  6. Mechanically Robust Superhydrophobic Surfaces for Turbulent Drag Reduction

    Science.gov (United States)

    Golovin, Kevin; Boban, Mathew; Xia, Charlotte; Tuteja, Anish

    2014-11-01

    Superhydrophobic surfaces (SHS) resist wetting by keeping a thin air layer within their texture. Such surfaces have been shown to reduce skin friction during laminar and transitional flows. However, turbulent boundary layer flows exhibit high shear stresses that damage the fragile microstructure of most SHS, and it is yet unclear to what extent these surfaces can reduce drag. Moreover, the increasing pressure fluctuations and decreasing wall unit length experienced during turbulent flow makes designing mechanically robust SHS with the correct roughness scales a challenge. In this work we evaluate many different SHS in terms of their hydrophobicity, mechanical durability and roughness. Whereas even commercially available SHS lose their superhydrophobic properties after slight mechanical abrasion, our novel coatings survive up to 200x longer. Moreover, we evaluate how the roughness of such surfaces changes with mechanical abrasion, and we design SHS with the correct roughness to display optimal drag reduction in turbulent boundary layer flows. Funding from ONR.

  7. Hierarchically nanotextured surfaces maintaining superhydrophobicity under severely adverse conditions

    Science.gov (United States)

    Maitra, Tanmoy; Antonini, Carlo; Auf der Mauer, Matthias; Stamatopoulos, Christos; Tiwari, Manish K.; Poulikakos, Dimos

    2014-07-01

    Superhydrophobic surfaces are highly desirable for a broad range of technologies and products affecting everyday life. Despite significant progress in recent years in understanding the principles of hydrophobicity, mostly inspired by surface designs found in nature, many man-made surfaces employ readily processable materials, ideal to demonstrate principles, but with little chance of survivability outside a very limited range of well-controlled environments. Here we focus on the rational development of robust, hierarchically nanostructured, environmentally friendly, metal-based (aluminum) superhydrophobic surfaces, which maintain their performance under severely adverse conditions. Based on their functionality, we superpose selected hydrophobic layers (i.e. self-assembled monolayers, thin films, or nanofibrous coatings) on hierarchically textured aluminum surfaces, collectively imparting high level robustness of superhydrophobicity under adverse conditions. These surfaces simultaneously exhibit chemical stability, mechanical durability and droplet impalement resistance. They impressively maintained their superhydrophobicity after exposure to severely adverse chemical environments like strong alkaline (pH ~ 9-10), acidic (pH ~ 2-3), and ionic solutions (3.5 weight% of sodium chloride), and could simultaneously resist water droplet impalement up to an impact velocity of 3.2 m s-1 as well as withstand standard mechanical durability tests.Superhydrophobic surfaces are highly desirable for a broad range of technologies and products affecting everyday life. Despite significant progress in recent years in understanding the principles of hydrophobicity, mostly inspired by surface designs found in nature, many man-made surfaces employ readily processable materials, ideal to demonstrate principles, but with little chance of survivability outside a very limited range of well-controlled environments. Here we focus on the rational development of robust, hierarchically

  8. Enhanced water droplet mobility on superhydrophobic rippled nanoshell array

    Science.gov (United States)

    Im, Hwon; Ji, Seungmuk; Moon, Dong-Il; Lim, Hyuneui; Choi, Yang-Kyu

    2016-10-01

    A 3-dimensional rippled nanoshell structure (a hollow pillar with wriggly sidewall morphology) is demonstrated for superhydrophobicity. As a control group, a straight nanoshell structure without a rippled shape was also prepared. The rippled structure showed improved superhydrophobicity with a large contact angle and a small sliding angle compared to the straight nanoshell structure. These enhancements originate from the minimum of interfacial energy at the triple-phase contact line, which is located at the most protruded circular line along the rippled structure. Using a drop impingement test, the stabilization of a Cassie Baxter state on the rippled structure was also verified. The experimental observation of wetting transition from a Cassie-Baxter to a Wenzel state is well explained by a revamped capillary pressure model, which was customized for the rippled structure.

  9. Wetting, superhydrophobicity, and icephobicity in biomimetic composite materials

    Science.gov (United States)

    Hejazi, Vahid

    Recent developments in nano- and bio-technology require new materials. Among these new classes of materials which have emerged in the recent years are biomimetic materials, which mimic structure and properties of materials found in living nature. There are a large number of biological objects including bacteria, animals and plants with properties of interest for engineers. Among these properties is the ability of the lotus leaf and other natural materials to repel water, which has inspired researchers to prepare similar surfaces. The Lotus effect involving roughness-induced superhydrophobicity is a way to design nonwetting, self-cleaning, omniphobic, icephobic, and antifouling surfaces. The range of actual and potential applications of superhydrophobic surfaces is diverse including optical, building and architecture, textiles, solar panels, lab-on-a-chip, microfluidic devices, and applications requiring antifouling from biological and organic contaminants. In this thesis, in chapter one, we introduce the general concepts and definitions regarding the wetting properties of the surfaces. In chapter two, we develop novel models and conduct experiments on wetting of composite materials. To design sustainable superhydrophobic metal matrix composite (MMC) surfaces, we suggest using hydrophobic reinforcement in the bulk of the material, rather than only at its surface. We experimentally study the wetting properties of graphite-reinforced Al- and Cu-based composites and conclude that the Cu-based MMCs have the potential to be used in the future for the applications where the wear-resistant superhydrophobicity is required. In chapter three, we introduce hydrophobic coating at the surface of concrete materials making them waterproof to prevent material failure, because concretes and ceramics cannot stop water from seeping through them and forming cracks. We create water-repellant concretes with CA close to 160o using superhydrophobic coating. In chapter four, experimental

  10. Scale effect on dropwise condensation on superhydrophobic surfaces.

    Science.gov (United States)

    Lo, Ching-Wen; Wang, Chi-Chuan; Lu, Ming-Chang

    2014-08-27

    Micro/nano (two-tier) structures are often employed to achieve superhydrophobicity. In condensation, utilizing such a surface is not necessarily advantageous because the macroscopically observed Cassie droplets are usually in fact partial Wenzel in condensation. The increase in contact angle through introducing microstructures on such two-tier roughened surfaces may result in an increase in droplet departure diameter and consequently deteriorate the performance. In the meantime, nanostructure roughened surfaces could potentially yield efficient shedding of liquid droplets, whereas microstructures roughened surfaces often lead to highly pinned Wenzel droplets. To attain efficient shedding of liquid droplets in condensation on a superhydrophobic surface, a Bond number (a dimensionless number for appraising dropwise condensation) and a solid-liquid fraction smaller than 0.1 and 0.3, respectively, are suggested.

  11. Simple nanofabrication of a superhydrophobic and transparent biomimetic surface

    Institute of Scientific and Technical Information of China (English)

    LIM Hyuneui; JUNG Dae-Hwan; NOH Jung-Hyun; CHOI Gyeong-Rin; KIM Wan-Doo

    2009-01-01

    This paper describes a simple fabrication method for creating superhydrophobic and transparent glass surfaces that mimic natural surfaces such as lotus leaves, moth eyes or cicada wings. Nanostructured glass surfaces were created by a combination of colloidal lithography and plasma etching. A colloidal mask was formed simply by the spin coating of the polystyrene beads and with modification of the interparticle distance between the beads. The etching of the glasses was conducted by CF_4 plasma. Tower-shaped nanostructures at an aspect ratio of 1:4 were treated using fluoroalkylsilane self-assembled monolayers (SAMs) to obtain the hydrophobic surfaces. The treated glass surfaces showed superhydrophobicity with a water contact angle of around 150° and a hexadecane contact angle of around 110°. Furthermore, the nanostructured glass was transparent to visible light.

  12. Modeling contact angle hysteresis on chemically patterned and superhydrophobic surfaces.

    Science.gov (United States)

    Kusumaatmaja, H; Yeomans, J M

    2007-05-22

    We investigate contact angle hysteresis on chemically patterned and superhydrophobic surfaces, as the drop volume is quasistatically increased and decreased. We consider both two (cylindrical drops) and three (spherical drops) dimensions using analytical and numerical approaches to minimize the free energy of the drop. In two dimensions, we find, in agreement with other authors, a slip, jump, stick motion of the contact line. In three dimensions, this behavior persists, but the position and magnitude of the contact line jumps are sensitive to the details of the surface patterning. In two dimensions, we identify analytically the advancing and receding contact angles on the different surfaces, and we use numerical insights to argue that these provide bounds for the three-dimensional cases. We present explicit simulations to show that a simple average over the disorder is not sufficient to predict the details of the contact angle hysteresis and to support an explanation for the low contact angle hysteresis of suspended drops on superhydrophobic surfaces.

  13. Drops transformed from a continuous flow on a superhydrophobic incline

    Science.gov (United States)

    Katariya, Mayur; Ng, Tuck Wah

    2013-08-01

    Biochemical analysis with discrete drops on superhydrophobic surfaces will benefit from low loss, low contamination and open access features, but is challenged by the ability to generate them. A simple approach for delivering the drops from a continuous flow through an inclined superhydrophobic surface here showed the rear pinning contact line to be strongly influential in retention, providing potential for volume control, yet without any lossy daughter droplet formation. At a high flowrate regime prior to jetting, the liquid body was found to develop a grown out section that was able to flip up and down to be airborne, depending on the gravitational effect. While the section was airborne, the drop was able to increase its volume without the action of the three-phase mechanics dictating detachment.

  14. How water droplets evaporate on a superhydrophobic substrate

    CERN Document Server

    Gelderblom, Hanneke; Nair, Hrudya; van Houselt, Arie; Lefferts, Leon; Snoeijer, Jacco H; Lohse, Detlef

    2010-01-01

    Evaporation of water droplets on a superhydrophobic substrate, on which the contact line is pinned, is investigated. While previous studies mainly focused on droplets with contact angles smaller than $90^\\circ$, here we analyze almost the full range of possible contact angles (10$^\\circ$-150$^\\circ$). The greater contact angles and pinned contact lines can be achieved by the use of superhydrophobic Carbon Nanofiber substrates. The time-evolutions of the contact angle and the droplet mass are examined. The experimental data is in good quantitative agreement with the model presented by Popov (Physical Review E 71, 2005), demonstrating that the evaporation process is quasi-static, diffusion-driven, and that thermal effects play no role. Furthermore, we show that the experimental data for the evolution of both the contact angle and the droplet mass can be collapsed onto one respective universal curve for all droplet sizes and initial contact angles.

  15. Bouncing dynamics of impact droplets on the convex superhydrophobic surfaces

    Science.gov (United States)

    Shen, Yizhou; Liu, Senyun; Zhu, Chunling; Tao, Jie; Chen, Zhong; Tao, Haijun; Pan, Lei; Wang, Guanyu; Wang, Tao

    2017-05-01

    Bouncing dynamics of impact droplets on solid surfaces intensively appeal to researchers due to the importance in many industrial fields. Here, we found that droplets impacting onto dome convex superhydrophobic surfaces could rapidly bounce off with a 28.5% reduction in the contact time, compared with that on flat superhydrophobic surfaces. This is mainly determined by the retracting process of impact droplets. Under the action of dome convexity, the impact droplet gradually evolves into an annulus shape with a special hydrodynamic distribution. As a consequence, both the inner and external rims of the annulus shape droplet possess a higher retracting velocity under the actions of the inertia force and the surface energy change, respectively. Also, the numerical simulation provides a quantitative evidence to further verify the interpretation on the regimes behind the rapidly detached phenomenon of impact droplets.

  16. Microcavity-array superhydrophobic surfaces: Limits of the model

    Science.gov (United States)

    Salvadori, M. C.; Oliveira, M. R. S.; Spirin, R.; Teixeira, F. S.; Cattani, M.; Brown, I. G.

    2013-11-01

    Superhydrophobic surfaces formed of microcavities can be designed with specific desired advancing and receding contact angles using a new model described by us in prior work. Here, we discuss the limits of validity of the model, and explore the application of the model to surfaces fabricated with small cavities of radius 250 nm and with large cavities of radius 40 μm. The Wenzel model is discussed and used to calculate the advancing and receding contact angles for samples for which our model cannot be applied. We also consider the case of immersion of a sample containing microcavities in pressurized water. A consideration that then arises is that the air inside the cavities can be dissolved in the water, leading to complete water invasion into the cavities and compromising the superhydrophobic character of the surface. Here, we show that this effect does not destroy the surface hydrophobia when the surface is subsequently removed from the water.

  17. Bioinspired superhydrophobic, self-cleaning and low drag surfaces

    Science.gov (United States)

    Bhushan, Bharat

    2013-09-01

    Nature has evolved objects with desired functionality using commonly found materials. Nature capitalizes on hierarchical structures to achieve functionality. The understanding of the functions provided by objects and processes found in nature can guide us to produce nanomaterials, nanodevices, and processes with desirable functionality. This article provides an overview of four topics: (1) Lotus Effect used to develop superhydrophobic and self-cleaning/antifouling surfaces with low adhesion, (2) Shark Skin Effect to develop surfaces with low fluid drag and anti-fouling characteristics, and (3-4) Rice Leaf and Butterfly Wing Effect to develop superhydrophobic and self-cleaning surfaces with low drag. Rice Leaf and Butterfly Wings combine the Shark Skin and Lotus Effects.

  18. Biomimetic Superhydrophobic Biobased Polyurethane-Coated Fertilizer with Atmosphere "Outerwear".

    Science.gov (United States)

    Xie, Jiazhuo; Yang, Yuechao; Gao, Bin; Wan, Yongshan; Li, Yuncong C; Xu, Jing; Zhao, Qinghua

    2017-05-10

    The development of efficient biobased controlled-release fertilizers has captured much research attention because of the environmental concerns and food scarcity problems. In this work, a biomimetic superhydrophobic biobased polyurethane-coated fertilizer (SBPF) was successfully fabricated by increasing surface roughness and reducing surface energy of polyurethane (PU) coating. The green PU coating was synthesized from low-cost, biodegradable, and renewable cottonseed oil. The nutrient release longevity of SBPF revealed 2-fold enhancement compared with the normal biobased PU-coated fertilizer (BPF). The significant improvement of nutrient release characteristics can be attributed to the atmosphere "outerwear" which ensured the nonwetting contact of water with superhydrophobic surfaces in gas state instead of in liquid state. The new concept introduced in this study can inform the development of the next generation of biobased controlled release fertilizers.

  19. Superhydrophobic activated carbon-coated sponges for separation and absorption.

    Science.gov (United States)

    Sun, Hanxue; Li, An; Zhu, Zhaoqi; Liang, Weidong; Zhao, Xinhong; La, Peiqing; Deng, Weiqiao

    2013-06-01

    Highly porous activated carbon with a large surface area and pore volume was synthesized by KOH activation using commercially available activated carbon as a precursor. By modification with polydimethylsiloxane (PDMS), highly porous activated carbon showed superhydrophobicity with a water contact angle of 163.6°. The changes in wettability of PDMS- treated highly porous activated carbon were attributed to the deposition of a low-surface-energy silicon coating onto activated carbon (confirmed by X-ray photoelectron spectroscopy), which had microporous characteristics (confirmed by XRD, SEM, and TEM analyses). Using an easy dip-coating method, superhydrophobic activated carbon-coated sponges were also fabricated; those exhibited excellent absorption selectivity for the removal of a wide range of organics and oils from water, and also recyclability, thus showing great potential as efficient absorbents for the large-scale removal of organic contaminants or oil spills from water.

  20. Droplet detachment by air flow for microstructured superhydrophobic surfaces.

    Science.gov (United States)

    Hao, Pengfei; Lv, Cunjing; Yao, Zhaohui

    2013-04-30

    Quantitative correlation between critical air velocity and roughness of microstructured surface has still not been established systematically until the present; the dynamics of water droplet detachment by air flow from micropillar-like superhydrophobic surfaces is investigated by combining experiments and simulation comparisons. Experimental evidence demonstrates that the onset of water droplet detachment from horizontal micropillar-like superhydrophobic surfaces under air flow always starts with detachment of the rear contact lines of the droplets from the pillar tops, which exhibits a similar dynamic mechanism for water droplet motion under a gravity field. On the basis of theoretical analysis and numerical simulation, an explicit analytical model is proposed for investigating the detaching mechanism, in which the critical air velocity can be fully determined by several intrinsic parameters: water-solid interface area fraction, droplet volume, and Young's contact angle. This model gives predictions of the critical detachment velocity of air flow that agree well with the experimental measurements.

  1. Study of superhydrophobic electrospun nanocomposite fibers for energy systems.

    Science.gov (United States)

    Asmatulu, Ramazan; Ceylan, Muhammet; Nuraje, Nurxat

    2011-01-18

    Polystyrene (PS) and polyvinyl chloride (PVC) fibers incorporated into TiO(2) nanoparticles and graphene nanoflakes were fabricated by an electrospinning technique, and then the surface morphology and superhydrophobicity of these electrospun nanocomposite fibers were investigated. Results indicated that the water contact angle of the nanocomposite fiber surfaces increases to 178° on the basis of the fiber diameter, material type, nanoscale inclusion, heat treatment, and surface porosity/roughness. This is a result of the formation of the Cassie-Baxter state in the fibers via the nanoparticle decoration, bead formation, and surface energy of the nanofiber surface. Consequently, these superhydrophobic nanocomposite fibers can be utilized in designing photoelectrodes of dye-sensitized solar cells (DSSCs) as self-cleaning and anti-icing materials for the long-term efficiency of the cells.

  2. Combination of bioinspiration: a general route to superhydrophobic particles.

    Science.gov (United States)

    Zhang, Liang; Wu, Junjie; Wang, Yongxin; Long, Yuhua; Zhao, Ning; Xu, Jian

    2012-06-20

    We combine two amazing abilities found in nature: the superhydrophobic property of lotus leaf and the adhesive ability of mussel adhesive protein. The molecular structure mimic of the single units of adhesive proteins, dopamine, was polymerized in an alkaline aqueous solution to encapsulate microparticles. The as-formed thin polydopamine walls worked as reactive templates to generate silver nanoparticles on the capsuled particles. As a result, core/shell/satellite composite particles were generated with a hierarchical structure similar to the micromorphology of lotus leaf. The composite particles exhibited extremely water repellence after fluorination. Because dopamine can deposit and adhere to all kinds of materials, this method can be applied to diverse microparticles, from organic to inorganic. In addition, particles of different sizes and matters can be modified to superhydrophobic particles in one pot. Magnetic particles have also been prepared which could be used as oil-absorbent and magnetic controlled carriers. "Oil marbles" formed underwater were achieved for the first time.

  3. Two-step activation of meiosis by the mat1 locus in Schizosaccharomyces pombe

    DEFF Research Database (Denmark)

    Willer, M; Hoffmann, Ulla-Lisbeth; Styrkársdóttir, U

    1995-01-01

    The mat1 locus is a key regulator of both conjugation and meiosis in the fission yeast Schizosaccharomyces pombe. Two alternative DNA segments of this locus, mat1-P and mat1-M, specify the haploid cell types (Plus and Minus). Each segment includes two genes: mat1-P includes mat1-Pc and mat1-Pm, w...

  4. Microbial mats: an ecological niche for fungi

    Directory of Open Access Journals (Sweden)

    Sharon A Cantrell

    2013-04-01

    Full Text Available Fungi were documented in tropical hypersaline microbial mats and their role in the degradation of complex carbohydrates (exopolimeric substance – EPS was explored. Fungal diversity is higher during the wet season with Acremonium, Aspergillus, Cladosporium and Penicillium among the more common genera. Diversity is also higher in the oxic layer and in young and transient mats. Enrichments with xanthan (a model EPS show that without antibiotics (full community, degradation is faster than enrichments with antibacterial (fungal community and antifungal (bacterial community agents, suggesting that degradation is performed by a consortium of organisms (bacteria and fungi. The combined evidence from all experiments indicates that bacteria carried out approximately 2/3 of the xanthan degradation. The pattern of degradation is similar between seasons and layers but degradation is faster in enrichments from the wet season. The research suggests that fungi thrive in these hypersaline consortia and may participate in the carbon cycle through the degradation of complex carbohydrates.

  5. Experimental studies of liquid marbles and superhydrophobic surfaces

    OpenAIRE

    Elliott, SJ

    2009-01-01

    The interaction of water droplets with hydrophobic or rough, superhydrophobic solid surfaces has been studied. Such surfaces may be found in the natural world and their potential applications range from waterproof and self-cleaning surfaces to droplet microfluidics. A measure of hydrophobicity is obtained from the angle between the liquid and solid surface measured from the solid through the liquid, known as the contact angle. Variations in this angle can indicate not only a level of ‘wetting...

  6. Robust hybrid elastomer/metal-oxide superhydrophobic surfaces.

    Science.gov (United States)

    Hoshian, S; Jokinen, V; Franssila, S

    2016-08-21

    We introduce a new type of hybrid material: a nanostructured elastomer covered by a hard photoactive metal-oxide thin film resembling the exoskeleton of insects. It has extreme water repellency and fast self-recovery after damage. A new fabrication method for replicating high aspect ratio, hierarchical re-entrant aluminum structures into polydimethylsiloxane (PDMS) is presented. The method is based on a protective titania layer deposited by atomic layer deposition (ALD) on the aluminum template. The ALD titania transfers to the elastomeric scaffold via sacrificial release etching. The sacrificial release method allows for high aspect ratio, even 100 μm deep and successful release of overhanging structures, unlike conventional peeling. The ALD titania conformally covers the 3D multihierarchical structures of the template and protects the polymer during the release etch. Afterwards it prevents the high aspect ratio nanostructures from elasticity based collapse. The resulting nanostructured hybrid PDMS/titania replicas display robust superhydrophobicity without any further fluoro-coating or modification. Their mechanical and thermal robustness results from a thick nanostructured elastomeric layer which is conformally covered by ceramic titania instead of a monolayer hydrophobic coating. We have demonstrated the durability of these replicas against mechanical abrasion, knife scratches, rubbing, bending, peel tape test, high temperature annealing, UV exposure, water jet impingement and long term underwater storage. Though the material loses its superhydrophobicity in oxygen plasma exposure, a fast recovery from superhydrophilic to superhydrophobic can be achieved after 20 min UV irradiation. UV-assisted recovery is correlated with the high photoactivity of ALD titania film. This novel hybrid material will be applicable to the large area superhydrophobic surfaces in practical outdoor applications.

  7. Microdroplet growth mechanism during water condensation on superhydrophobic surfaces.

    Science.gov (United States)

    Rykaczewski, Konrad

    2012-05-22

    By promoting dropwise condensation of water, nanostructured superhydrophobic coatings have the potential to dramatically increase the heat transfer rate during this phase change process. As a consequence, these coatings may be a facile method of enhancing the efficiency of power generation and water desalination systems. However, the microdroplet growth mechanism on surfaces which evince superhydrophobic characteristics during condensation is not well understood. In this work, the sub-10 μm dynamics of droplet formation on nanostructured superhydrophobic surfaces are studied experimentally and theoretically. A quantitative model for droplet growth in the constant base (CB) area mode is developed. The model is validated using optimized environmental scanning electron microscopy (ESEM) imaging of microdroplet growth on a superhydrophobic surface consisting of immobilized alumina nanoparticles modified with a hydrophobic promoter. The optimized ESEM imaging procedure increases the image acquisition rate by a factor of 10-50 as compared to previous research. With the improved imaging temporal resolution, it is demonstrated that nucleating nanodroplets coalesce to create a wetted flat spot with a diameter of a few micrometers from which the microdroplet emerges in purely CB mode. After the droplet reaches a contact angle of 130-150°, its base diameter increases in a discrete steplike fashion. The droplet height does not change appreciably during this steplike base diameter increase, leading to a small decrease of the contact angle. Subsequently, the drop grows in CB mode until it again reaches the maximum contact angle and increases its base diameter in a steplike fashion. This microscopic stick-and-slip motion can occur up to four times prior to the droplet coalescence with neighboring drops. Lastly, the constant contact angle (CCA) and the CB growth models are used to show that modeling formation of a droplet with a 150° contact angle in the CCA mode rather than in

  8. Superhydrophobic coated apparatus for liquid purification by evaporative condensation

    Science.gov (United States)

    Simpson, John T; McNeany, Steve R; Dinsmore, Thomas V; Hunter, Scott R; Ivanov, Ilia N

    2014-03-11

    Disclosed are examples of apparatuses for evaporative purification of a contaminated liquid. In each example, there is a first vessel for storing the contaminated fluid. The first vessel includes a surface coated with a layer of superhydrophobic material and the surface is at least partially in contact with the contaminated liquid. The contaminants do not adhere to the surface as the purified liquid evaporates, thus simplifying maintenance of the apparatus.

  9. Facile Method to Prepare Superhydrophobic and Water Repellent Cellulosic Paper

    OpenAIRE

    Ioannis Karapanagiotis; Diana Grosu; Dimitra Aslanidou; Aifantis, Katerina E.

    2015-01-01

    Silica nanoparticles (7 nm) were dispersed in solutions of a silane/siloxane mixture. The dispersions were applied, by brush, on four types of paper: (i) modern, unprinted (blank) paper, (ii) modern paper where a text was printed using a common laser jet printer, (iii) a handmade paper sheet detached from an old book, and (iv) Japanese tissue paper. It is shown that superhydrophobicity and water repellency were achieved on the surface of the deposited films, when high particle concentrations ...

  10. PARTICLE DEPOSITION ON SUPERHYDROPHOBIC SURFACES BY SESSILE DROPLET EVAPORATION

    OpenAIRE

    Dicuangco, Mercy G.

    2014-01-01

    Prediction and active control of the spatial distribution of particulate deposits obtained from sessile droplet evaporation is essential in ink-jet printing, nanostructure assembly, biotechnology, and other applications that require localized deposits. In recent years, sessile droplet evaporation on bio-inspired superhydrophobic surfaces has become an attractive method for depositing materials on a site-specific, localized region, but is less explored compared to evaporative deposition on hyd...

  11. Formation mechanism of robust silver nanoparticle film with superhydrophobicity

    Science.gov (United States)

    Guo, Zhiguang; Liu, Weimin

    2010-12-01

    The promising formation mechanism of Ag nanoparticles on a Si wafer displaying superhydrophobicity, generated by means of a facile in situ galvanic cell route, is discussed. The results showed that the promising formation of Ag nanoparticles is based on a microelectrochemical redox reaction in which both the anodic process and the cathodic process occur simultaneously on the silicon substrate surface. This discovery could be of great importance in the design of other metal/semiconductor systems.

  12. Impregnation of thermoplastic resin in jute fiber mat

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Impregnation rate of thermoplastic resin (polypropylene) in jute fiber mat and influence of relative factors on impregnation were studied,aiming to develop the continuous melt impregnation technique and to investigate the effect of impregnation rate and temperature on processing conditions and mechanical properties of natural fiber mat-reinforced thermoplastics.Influence of pressure on porosity of fiber mat and effect of melt viscosity on impregnation rate were also investigated.The modified capillary rheometer was used as apparatus and experimental data were analyzed based on the one-dimension Darcy's law.Results showed that at a given pressure,the impregnation rate is inversely proportional to melt viscosity and jute fiber mat has higher porosity than glass fiber mat.The architecture,compressibility,permeability and fiber diameter of jute fiber mat were compared with those of glass fiber mat and their effects on impregnation were discussed further.It could be seen that the average diameter of jute fiber is much bigger;the porosity of jute fiber mat is significantly higher and inner bundle impregnation does not exist in jute fiber mat.Therefore,it is not difficult to understand why the impregnation rate in jute fiber mat is 3.5 times higher and permeability is 14 times greater.Kozeny constants of jute and glass fiber mats calculated based on the capillary model are 2950 and 442,respectively.

  13. Facile preparation of superhydrophobic surfaces based on metal oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Xue-Mei; Cui, Jin-Feng; Sun, Han-Xue; Liang, Wei-Dong; Zhu, Zhao-Qi; An, Jin; Yang, Bao-Ping; La, Pei-Qing; Li, An, E-mail: lian2010@lut.cn

    2014-06-01

    A novel method for fabrication of superhydrophobic surfaces was developed by facile coating various metal oxide nanoparticles, including ZnO, Al{sub 2}O{sub 3} and Fe{sub 3}O{sub 4}, on various substrates followed by treatment with polydimethylsiloxane (PDMS) via chemical vapor deposition (CVD) method. Using ZnO nanoparticles as a model, the changes in the surface chemical composition and crystalline structures of the metal oxide nanoparticles by PDMS treatment were investigated by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The results show that the combination of the improved surface roughness generated from of the nanoparticles aggregation with the low surface-energy of silicon-coating originated from the thermal pyrolysis of PDMS would be responsible for the surface superhydrophobicity. By a simple dip-coating method, we show that the metal oxide nanoparticles can be easily coated onto the surfaces of various textural and dimensional substrates, including glass slide, paper, fabric or sponge, for preparation of superhydrophobic surfaces for different purpose. The present strategy may provide an inexpensive and new route to surperhydrophobic surfaces, which would be of technological significance for various practical applications especially for separation of oils or organic contaminates from water.

  14. Contact-angle hysteresis on super-hydrophobic surfaces.

    Science.gov (United States)

    McHale, G; Shirtcliffe, N J; Newton, M I

    2004-11-09

    The relationship between perturbations to contact angles on a rough or textured surface and the super-hydrophobic enhancement of the equilibrium contact angle is discussed theoretically. Two models are considered. In the first (Wenzel) case, the super-hydrophobic surface has a very high contact angle and the droplet completely contacts the surface upon which it rests. In the second (Cassie-Baxter) case, the super-hydrophobic surface has a very high contact angle, but the droplet bridges across surface protrusions. The theoretical treatment emphasizes the concept of contact-angle amplification or attenuation and distinguishes between the increases in contact angles due to roughening or texturing surfaces and perturbations to the resulting contact angles. The theory is applied to predicting contact-angle hysteresis on rough surfaces from the hysteresis observable on smooth surfaces and is therefore relevant to predicting roll-off angles for droplets on tilted surfaces. The theory quantitatively predicts a "sticky" surface for Wenzel-type surfaces and a "slippy" surface for Cassie-Baxter-type surfaces.

  15. Super-hydrophobic characteristics of butterfly wing surface

    Institute of Scientific and Technical Information of China (English)

    CONG Qian; CHEN Guang-hua; FANG Yan; REN Lu-quan

    2004-01-01

    Many biological surface are hydrophobic because of their complicated composition and surface microstructure. Eleven species (four families) of butterflies were selected to study their micro-, nano-structure and super-hydrophobic characteristic by means of Confocal Light Microscopy, Scanning Electron Microscopy and Contact Angle Measurement. The contact angles of water droplets on the butterfly wing surface were consistently measured to be about 150° and 100° with and without the squamas, respectively. The dust on the surface can be easily cleaned by moving spherical droplets when the inclining angle is larger than 3°. It can be concluded that the butterfly wing surface possess a super-hydrophobic, water-repellent,self-cleaning, or "Lotus-effect" characteristic. The contact angle measurement of water droplets on the wing surface with and without the squamas showed that the water-repellent characteristic is a consequence of the microstructure of the squamas.Each water droplet (diameter 2 mm) can cover about 700 squamas with a size of 40 μm×80 μm of each squama. The regular riblets with a width of 1000 nm to 1500 nm are clearly observed on each single squama. Such nanostructure should play a very important role in their super-hydrophobic and self-cleaning characteristic.

  16. Dynamic Melting of Freezing Droplets on Ultraslippery Superhydrophobic Surfaces.

    Science.gov (United States)

    Chu, Fuqiang; Wu, Xiaomin; Wang, Lingli

    2017-03-08

    Condensed droplet freezing and freezing droplet melting phenomena on the prepared ultraslippery superhydrophobic surface were observed and discussed in this study. Although the freezing delay performance of the surface is common, the melting of the freezing droplets on the surface is quite interesting. Three self-propelled movements of the melting droplets (ice- water mixture) were found including the droplet rotating, the droplet jumping, and the droplet sliding. The melting droplet rotating, which means that the melting droplet rotates spontaneously on the superhydrophobic surface like a spinning top, is first reported in this study and may have some potential applications in various engineering fields. The melting droplet jumping and sliding are similar to those occurring during condensation but have larger size scale and motion scale, as the melting droplets have extra-large specific surface area with much more surface energy available. These self-propelled movements make all the melting droplets on the superhydrophobic surface dynamic, easily removed, which may be promising for the anti-icing/frosting applications.

  17. Shrink-induced superhydrophobic and antibacterial surfaces in consumer plastics.

    Directory of Open Access Journals (Sweden)

    Lauren R Freschauf

    Full Text Available Structurally modified superhydrophobic surfaces have become particularly desirable as stable antibacterial surfaces. Because their self-cleaning and water resistant properties prohibit bacteria growth, structurally modified superhydrophobic surfaces obviate bacterial resistance common with chemical agents, and therefore a robust and stable means to prevent bacteria growth is possible. In this study, we present a rapid fabrication method for creating such superhydrophobic surfaces in consumer hard plastic materials with resulting antibacterial effects. To replace complex fabrication materials and techniques, the initial mold is made with commodity shrink-wrap film and is compatible with large plastic roll-to-roll manufacturing and scale-up techniques. This method involves a purely structural modification free of chemical additives leading to its inherent consistency over time and successive recasting from the same molds. Finally, antibacterial properties are demonstrated in polystyrene (PS, polycarbonate (PC, and polyethylene (PE by demonstrating the prevention of gram-negative Escherichia coli (E. coli bacteria growth on our structured plastic surfaces.

  18. Effect of Superhydrophobic Surface of Titanium on Staphylococcus aureus Adhesion

    Directory of Open Access Journals (Sweden)

    Peifu Tang

    2011-01-01

    Full Text Available Despite the systemic antibiotics prophylaxis, orthopedic implants still remain highly susceptible to bacterial adhesion and resulting in device-associated infection. Surface modification is an effective way to decrease bacterial adhesion. In this study, we prepared surfaces with different wettability on titanium surface based on TiO2 nanotube to examine the effect of bacterial adhesion. Firstly, titanium plates were calcined to form hydrophilic TiO2 nanotube films of anatase phase. Subsequently, the nanotube films and inoxidized titaniums were treated with 1H, 1H, 2H, 2H-perfluorooctyl-triethoxysilane (PTES, forming superhydrophobic and hydrophobic surfaces. Observed by SEM and contact angle measurements, the different surfaces have different characteristics. Staphylococcus aureus (SA adhesion on different surfaces was evaluated. Our experiment results show that the superhydrophobic surface has contact angles of water greater than 150∘ and also shows high resistance to bacterial contamination. It is indicated that superhydrophobic surface may be a factor to reduce device-associated infection and could be used in clinical practice.

  19. Shrink-Induced Superhydrophobic and Antibacterial Surfaces in Consumer Plastics

    Science.gov (United States)

    Freschauf, Lauren R.; McLane, Jolie; Sharma, Himanshu; Khine, Michelle

    2012-01-01

    Structurally modified superhydrophobic surfaces have become particularly desirable as stable antibacterial surfaces. Because their self-cleaning and water resistant properties prohibit bacteria growth, structurally modified superhydrophobic surfaces obviate bacterial resistance common with chemical agents, and therefore a robust and stable means to prevent bacteria growth is possible. In this study, we present a rapid fabrication method for creating such superhydrophobic surfaces in consumer hard plastic materials with resulting antibacterial effects. To replace complex fabrication materials and techniques, the initial mold is made with commodity shrink-wrap film and is compatible with large plastic roll-to-roll manufacturing and scale-up techniques. This method involves a purely structural modification free of chemical additives leading to its inherent consistency over time and successive recasting from the same molds. Finally, antibacterial properties are demonstrated in polystyrene (PS), polycarbonate (PC), and polyethylene (PE) by demonstrating the prevention of gram-negative Escherichia coli (E. coli) bacteria growth on our structured plastic surfaces. PMID:22916100

  20. Superhydrophobic durable coating based on UV-photoreactive silica nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Nahum, T.; Dodiuk, H.; Dotan, A.; Kenig, S. [Department of Plastics Engineering, Shenkar College of Engineering and Design, 12 Anna Frank Street, Ramat Gan 52526 (Israel); Lellouche, J. P. [Department of Chemistry, Nanomaterials Research Center, Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramar-Gan, 52900 (Israel)

    2015-05-22

    Superhydrophobic surfaces with contact angle (CA) >150 and sliding angle (SA) <10 have been aroused curiosity over the years due to their various applications. Superhydrophobicity can be obtained tailoring the chemistry and the roughness of the surface, mimicking the Lotus flower. Most superhydrophobic surfaces based on secondary bonding lose their roughness in harsh conditions and are unsuitable for practical applications. Photoreactive SiO{sub 2} nanoparticles (NPs) based on benzophenone (BP) can be a very effective tool for formation of reactive species that function as a molecular bridge by covalent bonding between the NP and any polymer matrix with C-C and C-H bonds. The present work focused on thermoset radiation curing urethane acrylate. Upon UV irradiation reactive excited nπ* triplet benzophenone species are formed and react through hydrogen abstraction to form ketyl radicals which interact with a radicals from the UV irradiated polymer matrix to yield covalent bonding. Roughness was achieved by dipping the substrate in SiO{sub 2}@BPs NPs dispersion followed by irradiation. Fluoroalkylsilane was used to obtain hydrophobic top layer. AFM nano manipulation was used to verify the immobilization of NPs. Evaluation of durability was made using air flow at 300 km/hr. Preliminary results indicate the formation of super hydrophobic surfaces (CA>150 and SA<10) with improved stability.

  1. Self-propelled droplet behavior during condensation on superhydrophobic surfaces

    Science.gov (United States)

    Chu, Fuqiang; Wu, Xiaomin; Zhu, Bei; Zhang, Xuan

    2016-05-01

    Self-propelled droplet motion has applications in various engineering fields such as self-cleaning surfaces, heat transfer enhancement, and anti-icing methods. A superhydrophobic surface was fabricated using two simultaneous chemical reactions with droplet condensation experiments performed on the horizontal superhydrophobic surface to characterize the droplet behavior. The droplet behavior is classified into three types based on their motion features and leftover marks as immobile droplet coalescence, self-propelled droplet jumping, and self-propelled droplet sweeping. This study focuses on the droplet sweeping that occurs due to the ultra-small rolling angle of the superhydrophobic surface, where the resulting droplet sweeps along the surface, merging with all the droplets it meets and leaving a long, narrow, clear track with a large droplet at the end of the track. An easy method is developed to predict the droplet sweeping direction based on the relative positions of the droplets just before coalescence. The droplet sweeping always absorbs dozens of droplets and is not limited by the surface structures; thus, this sweeping has many useful applications. In addition, the relationships between the droplet behavior and the number of participating droplets are also analyzed statistically.

  2. Facile preparation of superhydrophobic surfaces based on metal oxide nanoparticles

    Science.gov (United States)

    Bao, Xue-Mei; Cui, Jin-Feng; Sun, Han-Xue; Liang, Wei-Dong; Zhu, Zhao-Qi; An, Jin; Yang, Bao-Ping; La, Pei-Qing; Li, An

    2014-06-01

    A novel method for fabrication of superhydrophobic surfaces was developed by facile coating various metal oxide nanoparticles, including ZnO, Al2O3 and Fe3O4, on various substrates followed by treatment with polydimethylsiloxane (PDMS) via chemical vapor deposition (CVD) method. Using ZnO nanoparticles as a model, the changes in the surface chemical composition and crystalline structures of the metal oxide nanoparticles by PDMS treatment were investigated by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The results show that the combination of the improved surface roughness generated from of the nanoparticles aggregation with the low surface-energy of silicon-coating originated from the thermal pyrolysis of PDMS would be responsible for the surface superhydrophobicity. By a simple dip-coating method, we show that the metal oxide nanoparticles can be easily coated onto the surfaces of various textural and dimensional substrates, including glass slide, paper, fabric or sponge, for preparation of superhydrophobic surfaces for different purpose. The present strategy may provide an inexpensive and new route to surperhydrophobic surfaces, which would be of technological significance for various practical applications especially for separation of oils or organic contaminates from water.

  3. Superhydrophobic Post Treatment and Coating Extenders for Improved Asset Sustainability

    Science.gov (United States)

    Trigwell, Steven; Montgomery, Eliza L.; Calle, Luz M.

    2015-01-01

    Launch structures, hardware, and ground support equipment, at NASA's John F. Kennedy Space Center in Florida, are exposed to a highly corrosive natural coastal marine environment. In addition, during launches, rocket exhaust deposition is also highly corrosive. Superhydrophobic coatings are being considered for additional corrosion protection on existing structures to enhance corrosion resistance and add an additional layer of protection against harsh environmental elements. These coatings have come into their own recently, and are now being investigated as corrosion protective coatings due to their water repelling capability. These coatings can be used on existing coatings, newly coated materials, or used on bare substrates. The coatings are not suitable for permanent corrosion protection, but can be used where additional corrosion control is desired or only when temporary corrosion control is needed, such as in hardware sitting on a launch pad for 30-45 days prior to a launch. In this study, superhydrophobic coatings were applied on various coated and uncoated substrates and exposed to the spaceport environment for various times up to 60 days. This paper highlights the current results of the superhydrophobic coatings performance evaluated by X-ray photoelectron spectroscopy, and contact angle measurements.

  4. Tuning Superhydrophobic Nanostructures to Enhance Jumping-Droplet Condensation

    Science.gov (United States)

    Mulroe, Megan; Srijanto, Bernadeta; Collier, Patrick; Boreyko, Jonathan

    2016-11-01

    It was recently discovered that condensation growing on a nanostructured superhydrophobic surface can spontaneously jump off the surface when two or more droplets coalesce together. The minimum droplet size for jumping to occur is of order 10 microns, but it is unclear whether this is the true lower limit of jumping droplets or simply a limitation of current superhydrophobic surfaces. Here, we analyze the dynamics of jumping droplets on six different superhydrophobic surfaces where the topography of the nanopillars was systematically varied. The critical diameter for jumping to occur was observed to be highly dependent upon the height and diameter of the nanopillars; surfaces with very tall and slender nanopillars enabled jumping droplets at a smaller critical size of order 1 micron. An energetic model of the incipient growth of condensate shows that the nanostructure topology affects the rate of increase of a growing droplet's apparent contact angle, with jumping being enabled at very large angles. These findings indicate that the true upper limit to the performance of jumping-droplet condensers has not yet been reached and can be further improved using advanced nanofabrication techniques.

  5. Fabrication of superhydrophobic niobium pentoxide thin films by anodization

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Bong-Yong [Future Convergence Ceramic Division, Korea Institute of Ceramic Engineering and Technology, Seoul 153-801 (Korea, Republic of); Jung, Eun-Hye [Future Convergence Ceramic Division, Korea Institute of Ceramic Engineering and Technology, Seoul 153-801 (Korea, Republic of); Department of Chemical Engineering, Inha University, Incheon 402-024 (Korea, Republic of); Kim, Jin-Ho, E-mail: jhkim@kicet.re.kr [Electronic and Optic Materials Division, Korea Institute of Ceramic Engineering and Technology, Seoul 153-801 (Korea, Republic of)

    2014-07-01

    We report a simple method to fabricate a niobium oxide film with a lotus-like micro–nano surface structure. Self-assembled niobium pentoxide (Nb{sub 2}O{sub 5}) films with superhydrophobic property were fabricated by an anodization and a hydrophobic treatment. This process has several advantages such as low cost, simplicity and easy coverage of a large area. The surface of fabricated Nb{sub 2}O{sub 5} film was changed from hydrophilic to superhydrophobic surface by a treatment using fluoroaldyltrimethoxysilane (FAS) solution. This value is considered to be the lowest surface free energy of any solid, based on the alignment of -CF{sub 3} groups on the surface. In particular, among FAS coated surfaces, the micro–nano complex cone structured Nb{sub 2}O{sub 5} film showed the highest water-repellent property with a static contact angle of ca. 162°. This study gives promising routes from biomimetic superhydrophobic surfaces.

  6. Drop impact and wettability: From hydrophilic to superhydrophobic surfaces

    Science.gov (United States)

    Antonini, Carlo; Amirfazli, Alidad; Marengo, Marco

    2012-10-01

    Experiments to understand the effect of surface wettability on impact characteristics of water drops onto solid dry surfaces were conducted. Various surfaces were used to cover a wide range of contact angles (advancing contact angle from 48° to 166°, and contact angle hysteresis from 5° to 56°). Several different impact conditions were analyzed (12 impact velocities on 9 different surfaces, among which 2 were superhydrophobic). Results from impact tests with millimetric drops show that two different regimes can be identified: a moderate Weber number regime (30 200), in which wettability effect is secondary, because capillary forces are overcome by inertial effects. In particular, results show the role of advancing contact angle and contact angle hysteresis as fundamental wetting parameters to allow understanding of different phases of drop spreading and beginning of recoiling. It is also shown that drop spreading on hydrophilic and superhydrophobic surfaces occurs with different time scales. Finally, if the surface is superhydrophobic, eventual impalement, i.e., transition from Cassie to Wenzel wetting state, which might occur in the vicinity of the drop impact area, does not influence drop maximum spreading.

  7. Drag Measurements in Laminar Flows over Superhydrophobic Porous Membranes

    Science.gov (United States)

    Ozsun, Ozgur; Yakhot, Victor; Ekinci, Kamil L.

    2012-02-01

    An anomalous hydrodynamic response has recently been observed in oscillating flows on mesh-like porous superhydrophobic membranes.ootnotetextS. Rajauria, O. Ozsun, J. Lawall, V. Yakhot, and K. L. Ekinci, Phys. Rev. Lett. 107, 174501 (2011) This effect was attributed to a stable Knudsen layer of gas at the solid-liquid interface. In this study, we investigate laminar channel flow over these porous superhydrophobic membranes. We have fabricated surfaces with solid area fraction φs, which can maintain intimate contact with both air and water reservoirs on either side. Typical structures have linear dimensions of 1.5 mm x 15 mm x 1 μm and pore area of 10 μm x 10 μm. The surfaces are enclosed with precisely machined plastic microchannels, where pressure driven flow of DI water is generated. Pressure drop across the microchannels is measured as a function of flow rate. Slip lengths are inferred from the Poiseuille relation as a function of φs and compared to that of similar standard superhydrophobic surfaces, which lack intimate contact with an air reservoir.

  8. Fabrication of robust and thermally stable superhydrophobic nanocomposite coatings based on thermoplastic polyurethane and silica nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Seyfi, Javad [School of Chemical Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Jafari, Seyed Hassan, E-mail: shjafari@ut.ac.ir [School of Chemical Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Khonakdar, Hossein Ali [Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Strasse 6, D-01069 Dresden (Germany); Sadeghi, Gity Mir Mohamad [Department of Polymer Engineering & Color Technology, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Zohuri, Gholamhossein [Polymer Group, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Hejazi, Iman [Department of Polymer Engineering & Color Technology, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Simon, Frank [Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Strasse 6, D-01069 Dresden (Germany)

    2015-08-30

    Highlights: • Superhydrophobic coatings were prepared from an intrinsically hydrophilic polymer. • The superhydrophobicity remained intact at elevated temperatures. • Polyurethane plays a key role in improving the mechanical robustness of the coatings. • A complete surface coverage of nanosilica is necessary for superhydrophobicity. - Abstract: In this paper, superhydrophobic nanocomposite coatings based on thermoplastic polyurethane (TPU) and modified nanosilica were fabricated using a simple solution-based method. The main challenge was to impart superhydrophobicity to an intrinsically hydrophilic polymer substrate. The prepared nanocomposite coatings were characterized by means of scanning electron microscopy, confocal microscopy and X-ray photoelectron spectroscopy. Based on the obtained results, it was proved that in order to achieve superhydrophobicity, no TPU macromolecule should be present on the coating's top layer, thus a complete coverage of coating's top layer by nanosilica particles was necessary for achieving ultra water repellent coatings. Mechanical and thermal resistance of the coatings, which are the main challenges in commercializing superhydrophobic surfaces, were also studied by drop impact and thermal annealing tests, respectively. It was proved that using TPU as a sublayer results in improving mechanical resistance of the coatings as compared with the pure silica nanocoating. Moreover, the samples showed an excellent resistance against elevated temperatures (150 °C) and remained superhydrophobic; however, further increment of the annealing temperatures to 200 °C caused the TPU macromolecules to migrate onto the top layer of the coatings significantly reducing the water repellency, which was visually proved by SEM.

  9. Inkjet printing for direct micropatterning of a superhydrophobic surface: Toward biomimetic fog harvesting surfaces

    KAUST Repository

    Zhang, Lianbin

    2015-01-01

    The preparation of biomimetic superhydrophobic surfaces with hydrophilic micro-sized patterns is highly desirable, but a one-step, mask-free method to produce such surfaces has not previously been reported. We have developed a direct method to produce superhydrophilic micropatterns on superhydrophobic surfaces based on inkjet printing technology. This work was inspired by the efficient fog-harvesting behavior of Stenocara beetles in the Namib Desert. A mussel-inspired ink consisting of an optimized solution of dopamine was applied directly by inkjet printing to superhydrophobic surfaces. Stable Wenzel\\'s microdroplets of the dopamine solution with well-defined micropatterns were obtained on these surfaces. Superhydrophilic micropatterns with well-controlled dimensions were then readily achieved on the superhydrophobic surfaces by the formation of polydopamine via in situ polymerization. The micropatterned superhydrophobic surfaces prepared by this inkjet printing method showed enhanced water collection efficiency compared with uniform superhydrophilic and superhydrophobic surfaces. This method can be used for the facile large-scale patterning of superhydrophobic surfaces with high precision and superior pattern stability and is therefore a key step toward patterning superhydrophobic surfaces for practical applications. This journal is

  10. Self-healing superhydrophobic fluoropolymer brushes as highly protein-repellent coatings

    NARCIS (Netherlands)

    Wang, Zhanhua; Zuilhof, Han

    2016-01-01

    Superhydrophobic surfaces with micro/nanostructures are widely used to prevent nonspecific adsorption of commercial polymeric and/or biological materials. Herein, a self-healing superhydrophobic and highly protein-repellent fluoropolymer brush was grafted onto nanostructured silicon by surface-in

  11. Biomimetic superhydrophobic polyolefin surfaces fabricated with a facile scraping, bonding and peeling method

    NARCIS (Netherlands)

    Feng, Huanhuan; Zheng, Tingting; Wang, Huiliang

    2016-01-01

    Inspired by the superhydrophobicity of juicy peach surface, on which microscale hairs are standing vertically to the surface plane, an extremely simple, inexpensive physical method is developed for fabrication of superhydrophobic polyolefin surfaces over large areas. This method includes three st

  12. Robust and thermal-healing superhydrophobic surfaces by spin-coating of polydimethylsiloxane.

    Science.gov (United States)

    Long, Mengying; Peng, Shan; Deng, Wanshun; Yang, Xiaojun; Miao, Kai; Wen, Ni; Miao, Xinrui; Deng, Wenli

    2017-12-15

    Superhydrophobic surfaces easily lose their excellent water-repellency after damages, which limit their broad applications in practice. Thus, the fabrication of superhydrophobic surfaces with excellent durability and thermal healing should be taken into consideration. In this work, robust superhydrophobic surfaces with thermal healing were successfully fabricated by spin-coating method. To achieve superhydrophobicity, cost-less and fluoride-free polydimethylsiloxane (PDMS) was spin-coated on rough aluminum substrates. After being spin-coated for one cycle, the superhydrophobic PDMS coated hierarchical aluminum (PDMS-H-Al) surfaces showed excellent tolerance to various chemical and mechanical damages in lab, and outdoor damages for 90days. When the PDMS-H-Al surfaces underwent severe damages such as oil contamination (peanut oil with high boiling point) or sandpaper abrasion (500g of force for 60cm), their superhydrophobicity would lose. Interestingly, through a heating process, cyclic oligomers generating from the partially decomposed PDMS acted as low-surface-energy substance on the damaged rough surfaces, leading to the recovery of superhydrophobicity. The relationship between the spin-coating cycles and surface wettability was also investigated. This paper provides a facile, fluoride-free and efficient method to fabricate superhydrophobic surfaces with thermal healing. Copyright © 2017. Published by Elsevier Inc.

  13. Identification of the mechanism that confers superhydrophobicity on 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Escobar, Ana M.; Llorca-Isern, Nuria; Rius-Ayra, Oriol

    2016-01-15

    This study develops a rapid method to confer superhydrophobicity on 316L stainless steel surfaces with an amphiphilic reagent such as dodecanoic acid. The highest contact angle (approaching 173°) was obtained after forming hierarchical structures with a non-aqueous electrolyte by an electrolytic process. Our goal was to induce superhydrophobicity directly on 316L stainless steel substrates and to establish which molecules cause the effect. The superhydrophobic behaviour is analysed by contact angle measurements, scanning electron microscopy (SEM), IR spectroscopy and atomic force microscopy (AFM). The growth mechanism is analysed using FE-SEM, TOF-SIMS and XPS in order to determine the molecules involved in the reaction and the growth. The TOF-SIMS analysis revealed that the Ni{sup 2+} ions react with lauric acid to create an ester on the stainless steel surface. - Highlights: • This study develops a rapid and facile approach to impart superhydrophobicity properties to 316L stainless steel surfaces with an amphiphilic reagent such as dodecanoic acid. Surface character changes from superhydrophilicity to superhydrophobicity. • This process changes the surface character from superhydrophilicity to superhydrophobicity. • The process based on electrolysis of a nickel salt in lauric acid provides superhydrophobic behaviour in 316L stainless steel. • The growth mechanism is proposed as a mode island (Volmert- Weber mode). • TOF-SIMS and XPS provided the identification of the molecules involved in the surface modification reaction on AISI 316L inducing superhydrophobicity.

  14. Robust superhydrophobic tungsten oxide coatings with photochromism and UV durability properties

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Ting [Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials and Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei University, Wuhan, 430062 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Guo, Zhiguang, E-mail: zguo@licp.cas.cn [Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials and Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei University, Wuhan, 430062 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China)

    2016-11-30

    Highlights: • Superhydrophobic tungsten oxide (TO) coatings with a water contact angle (WCA) of 155° and rolling angle of 3.5° were developed. • The superhydrophobic coatings have excellent mechanical robustness and UV durability. • The superhydrophobic TO coatings show the reversible convert of photochromism. • The coating exhibited excellent self-cleaning behavior due to its high WCA and low rolling angle. - Abstract: Robust superhydrophobic tungsten oxide (TO) coatings with a water contact angle (WCA) of 155° were developed for photochromism via a facile and substrate-independent route. Importantly, after scatch test on both a single and two orthogonal direction, the TO coating still exhibited superhydrophobic behavior, indicating excellent mechanical robustness. It is worth mentioning that the superhydrophobic TO coatings showed the reversible convert of photochromism of WO{sub 3} induced by alternating UV and visible light irradiation. Besides that, the TO coating remained superhydrophobicity after UV irradiation for 36 h, showing excellent UV durability. In addition, the coating showed good resistance to acidic droplets. Moreover, it can also be applied on other substrates, such as copper mesh, steel, paper and fiber. The coating exhibited excellent self-cleaning behavior due to its high WCA and low rolling angle. Overall, this work is a promising approach to design and produce functional superhydrophobic coatings for various substrates.

  15. Biomimetic superhydrophobic polyolefin surfaces fabricated with a facile scraping, bonding and peeling method

    NARCIS (Netherlands)

    Feng, Huanhuan; Zheng, Tingting; Wang, Huiliang

    2016-01-01

    Inspired by the superhydrophobicity of juicy peach surface, on which microscale hairs are standing vertically to the surface plane, an extremely simple, inexpensive physical method is developed for fabrication of superhydrophobic polyolefin surfaces over large areas. This method includes three st

  16. USAGE OF FILTERS FROM FIBROUS MATERIALS IN AMELIORATIVE AND HYDRO-TECHNICAL CONSTRUCTION

    Directory of Open Access Journals (Sweden)

    V. T. Klimkov

    2016-01-01

    Full Text Available Construction of first drainage tubular systems has been facing such problem as their protection against silting-up by soil particles penetrating through input openings. Searches and investigations have led to usage of various fibrous materials which are playing the role of filters. At the beginning glass-fibre mats have been widely applied for this purpose. However, the mats possessing good filtration properties have had a number of fundamental disadvantages. Works executed at the Institute of Mechanics of Metal Polymeric Systems (Gomel, Republic of Belarus have played a big role in usage of plastic materials. A new technology has been developed with the purpose to obtain thermally-bonded fibres from thermoplastic material. The fibres have been called as polyethylene mats. Investigation of their properties has been carried out under load and it has revealed that their lateral and longitudinal permeability becomes equal at specified pressures, in other words the material takes an isotropic state. The considered interactions of filtrating material and skeleton frame have shown that the main water filtration occurs directly above perforation holes while the material above blind frame sections does not participate in the process. Due to this a new design of the filtrating element has been developed and it can be used in water intake systems for surface and underground water. The filtrating element consists of the skeleton frame with openings and a filtration covering which is installed on the frame. Water-feeding groove cavities are located on the skeleton frame and they are dispersing from perforation holes in the form of beams. These grooves can have side branches of the second, third and other orders. As beam-like arrangement of grooves creates the shortest flow paths for filtrated water from periphery to frame holes and area of groove cross section exceeds the area of poral holes in water in-take covering by a factor of hundreds, it is possible

  17. Robust superhydrophobic tungsten oxide coatings with photochromism and UV durability properties

    Science.gov (United States)

    Jiang, Ting; Guo, Zhiguang

    2016-11-01

    Robust superhydrophobic tungsten oxide (TO) coatings with a water contact angle (WCA) of 155° were developed for photochromism via a facile and substrate-independent route. Importantly, after scatch test on both a single and two orthogonal direction, the TO coating still exhibited superhydrophobic behavior, indicating excellent mechanical robustness. It is worth mentioning that the superhydrophobic TO coatings showed the reversible convert of photochromism of WO3 induced by alternating UV and visible light irradiation. Besides that, the TO coating remained superhydrophobicity after UV irradiation for 36 h, showing excellent UV durability. In addition, the coating showed good resistance to acidic droplets. Moreover, it can also be applied on other substrates, such as copper mesh, steel, paper and fiber. The coating exhibited excellent self-cleaning behavior due to its high WCA and low rolling angle. Overall, this work is a promising approach to design and produce functional superhydrophobic coatings for various substrates.

  18. Facile transformation of superhydrophobicity to hydrophilicity by silica/poly(ε-caprolactone) composite film

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhengxin [Key Laboratory of Bio-Based Material Science and Technology, Ministry of Education, Northeast Forestry University, Harbin 150040 (China); Zhai, Xianglin [Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 (United States); Wang, Chengyu, E-mail: wangcy@nefu.edu.cn [Key Laboratory of Bio-Based Material Science and Technology, Ministry of Education, Northeast Forestry University, Harbin 150040 (China)

    2015-12-30

    Graphical abstract: - Highlights: • The superhydrophobic wood was prepared by an effective method with simple immersion and pipetting steps. • The superhydrophobic wood shows fast thermo-response wettability transition between superhydrophobicity and hydrophilicity. • The modified wood surface is stable to the corrosive liquids. - Abstract: A smart surface with thermo-responsive wettability was fabricated on the cross section of wood with simple bench chemistry. The surface showed fast response between superhydrophobic and hydrophilic under different temperatures. The reversible wettability from superhydrophobicity to hydrophilicity can be easily achieved by adjusting the temperature between 25 and 60 °C. This reversible wettability is resulted from the synergistic effect of the crystallinity transition of the polymer coated on the surface and the optimized roughness controlled by the silica particles with different sizes. Furthermore, the modified wood surface showed an excellent chemical stability to corrosive liquids under ambient conditions.

  19. Bioinspired Multifunctional Superhydrophobic Surfaces with Carbon-Nanotube-Based Conducting Pastes by Facile and Scalable Printing.

    Science.gov (United States)

    Han, Joong Tark; Kim, Byung Kuk; Woo, Jong Seok; Jang, Jeong In; Cho, Joon Young; Jeong, Hee Jin; Jeong, Seung Yol; Seo, Seon Hee; Lee, Geon-Woong

    2017-03-01

    Directly printed superhydrophobic surfaces containing conducting nanomaterials can be used for a wide range of applications in terms of nonwetting, anisotropic wetting, and electrical conductivity. Here, we demonstrated that direct-printable and flexible superhydrophobic surfaces were fabricated on flexible substrates via with an ultrafacile and scalable screen printing with carbon nanotube (CNT)-based conducting pastes. A polydimethylsiloxane (PDMS)-polyethylene glycol (PEG) copolymer was used as an additive for conducting pastes to realize the printability of the conducting paste as well as the hydrophobicity of the printed surface. The screen-printed conducting surfaces showed a high water contact angle (WCA) (>150°) and low contact angle hysteresis (WCA superhydrophobic surfaces also showed sticky superhydrophobic characteristics and were used to transport water droplets. Moreover, fabricated films on metal meshes were used for an oil/water separation filter, and liquid evaporation behavior was investigated on the superhydrophobic and conductive thin-film heaters by applying direct current voltage to the film.

  20. Dynamic behavior of water droplets and flashover characteristics on a superhydrophobic silicone rubber surface

    Science.gov (United States)

    Li, Yufeng; Jin, Haiyun; Nie, Shichao; Zhang, Peng; Gao, Naikui

    2017-05-01

    In this paper, a superhydrophobic surface is used to increase the flashover voltage when water droplets are present on a silicone rubber surface. The dynamic behavior of a water droplet and the associated flashover characteristics are studied on common and superhydrophobic silicone rubber surfaces under a high DC voltage. On common silicone rubber, the droplet elongates and the flashover voltage decreases with increasing droplet volume and conductivity. In contrast, the droplet slides off the superhydrophobic surface, leading to an increased flashover voltage. This droplet sliding is due to the low adhesion of the superhydrophobic surface and a sufficiently high electrostatic force provided by the DC voltage. Experimental results show that a superhydrophobic surface is effective at inhibiting flashover.

  1. One-step preparation of transparent superhydrophobic coatings using atmospheric arc discharge

    Science.gov (United States)

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

    2015-08-01

    In this letter, we report a fast, simple, and single step approach to the preparation of transparent super-hydrophobic coatings on a copper conductor via atmosphere pressure arc discharges. The preparation procedures, hydrophobic characteristics, anti-pollution capability, and transparency of the super-hydrophobic coating are presented. A dual micro- and nano-scale hierarchical structure is observed on the super-hydrophobic coating with a water contact angle greater than 150°. The coating is, thus, capable of removing a significant amount of contaminants with a small quantity of water droplets. Attenuated total reflection Fourier transform infrared spectroscopy indicates that hydrophobic methyl groups exist on the surface of the coating. The surface roughness measurement results prove that the super-hydrophobic surface obeys the Cassie-Baxter model and its light scattering is very weak. Results demonstrate the conceptual feasibility of production of optically transparent super-hydrophobic coating by arc spraying of polymers under the atmospheric pressure.

  2. A simple way to fabricate an aluminum sheet with superhydrophobic and self-cleaning properties

    Institute of Scientific and Technical Information of China (English)

    Yang Zhou; Wu Yi-Zhi; Ye Yi-Fan; Gong Mao-Gang; Xu Xiao-Liang

    2012-01-01

    A superhydrophobic aluminum sheet is fabricated via a hot water immersing process and subsequently surface modification with heptadecafluorodecyltrimethoxy-silane (HTMS).As revealed by the scan electron microscopy (SEM),X-ray diffraction (XRD),and Fourier-transform infrared spectrophotometer (FTIR) results,a rough pseudoboehmite film is formed on the aluminum sheet,and HTMS molecules are grafted on the film surface successfully.These two factors make the treated aluminum sheet present superhydrophobicity with a water contact angle larger than 160° and sliding angle less than 5°,and possess a self-cleaning property.Furthermore,the flexible superhydrophobic aluminum sheet could be pasted to a cylinder surface without destroying its superhydrophobicity.At the end,the effect of hot water treatment time on superhydrophobicity is investigated.

  3. Oxidative stress inhibition and oxidant activity by fibrous clays.

    Science.gov (United States)

    Cervini-Silva, Javiera; Nieto-Camacho, Antonio; Gómez-Vidales, Virginia

    2015-09-01

    Fibrous clays (sepiolite, palygorskite) are produced at 1.2m tonnes per year and have a wide range of industrial applications needing to replace long-fibre length asbestos. However, information on the beneficial effects of fibrous clays on health remains scarce. This paper reports on the effect of sepiolite (Vallecas, Spain) and palygorskite (Torrejón El Rubio, Spain) on cell damage via oxidative stress (determined as the progress of lipid peroxidation, LP). The extent of LP was assessed using the Thiobarbituric Acid Reactive Substances assay. The oxidant activity by fibrous clays was quantified using Electron-Paramagnetic Resonance. Sepiolite and palygorskite inhibited LP, whereby corresponding IC50 values were 6557±1024 and 4250±289μgmL(-1). As evidenced by dose-response experiments LP inhibition by palygorskite was surface-controlled. Fibrous clay surfaces did not stabilize HO species, except for suspensions containing 5000μgmL(-1). A strong oxidant (or weak anti-oxidant) activity favours the inhibition of LP by fibrous clays.

  4. Craniofacial fibrous dysplasia - A review of current management techniques

    Directory of Open Access Journals (Sweden)

    Yadavalli Guruprasad

    2012-01-01

    Full Text Available Fibrous dysplasia is a pathologic condition of bone of unknown etiology with no apparent familial, hereditary or congenital basis. Lichtenstein first coined the term in 1938 and in 1942 he and Jaffe separated it from other fibro-osseous lesions. It is a bone tumor that, although benign, has the potential to cause significant cosmetic and functional disturbance, particularly in the craniofacial skeleton. Its management poses significant challenges to the surgeon. Craniofacial fibrous dysplasia is 1 of 3 types of fibrous dysplasia that can affect the bones of the craniofacial complex, including the mandible and maxilla. Fibrous dysplasia is a skeletal developmental disorder of the bone-forming mesenchyme that manifests as a defect in osteoblastic differentiation and maturation. It is a lesion of unknown etiology, uncertain pathogenesis, and diverse histopathology. Fibrous dysplasia represents about 2, 5% of all bone tumors and over 7% of all benign tumours. Over the years, we have gained a better understanding of its etiology, clinical behavior, and both surgical and non-surgical treatments.

  5. Electrospun nanocomposite fibrous polymer electrolyte for secondary lithium battery applications

    Energy Technology Data Exchange (ETDEWEB)

    Padmaraj, O.; Rao, B. Nageswara; Jena, Paramananda; Satyanarayana, N., E-mail: nallanis2011@gmail.com [Department of Physics, Pondicherry University, Pondicherry-605014 (India); Venkateswarlu, M. [R and D, Amaraja batteries, Thirupathi-517501 (India)

    2014-04-24

    Hybrid nanocomposite [poly(vinylidene fluoride -co- hexafluoropropylene) (PVdF-co-HFP)/magnesium aluminate (MgAl{sub 2}O{sub 4})] fibrous polymer membranes were prepared by electrospinning method. The prepared pure and nanocomposite fibrous polymer electrolyte membranes were soaked into the liquid electrolyte 1M LiPF{sub 6} in EC: DEC (1:1,v/v). XRD and SEM are used to study the structural and morphological studies of nanocomposite electrospun fibrous polymer membranes. The nanocomposite fibrous polymer electrolyte membrane with 5 wt.% of MgAl{sub 2}O{sub 4} exhibits high ionic conductivity of 2.80 × 10{sup −3} S/cm at room temperature. The charge-discharge capacity of Li/LiCoO{sub 2} coin cells composed of the newly prepared nanocomposite [(16 wt.%) PVdF-co-HFP+(5 wt.%) MgAl{sub 2}O{sub 4}] fibrous polymer electrolyte membrane was also studied and compared with commercial Celgard separator.

  6. Recurring fibrous dysplasia of anthro maxillary with cranial base invasion

    Directory of Open Access Journals (Sweden)

    Sousa, Kátia Maria Marabuco de

    2009-09-01

    Full Text Available Introduction: Fibrous dysplasia is an osseous lesion with an unknown etiology. It is characterized by the osseous maturation insufficiency. It may affect any bone, but the affection of craniofacial bones is the most critical for otorhinolaryngology. Maxilla is the most affected facial bone and the orbitary invasion is an uncommon event. The symptoms are unspecific and for its low suspicion and uncommonness, the diagnosis is generally late. The monostotic form presents a slow growth and asymptomatic course and needs to be followed up. The polyostotic type has a progressive behavior and is associated to recurrence and complications. Objective: To present two cases of patients with fibrous dysplasia diagnosis and describe the clinical presentation, radiological findings and the treatment of this pathology. Cases Report: Two cases of fibrous dysplasia are reported, which initially presented unspecific symptomatology, but with characteristic radiologic signs. They were submitted to surgical treatment for resection of the lesions and evolved with frequent recurrences with extensive affection of the facial sinuses, one patient had cranial base invasion and frontal craniotomy was needed for tumoral excision. Final Comments: Fibrous dysplasia is an uncommon osteopathy. The tomography is the choice method for characterization of the tumoral expansion, and helps in the surgical planning. The surgical strategy is indicated for symptomatic lesions, functions alterations or anatomic disorders. This article describes two uncommon manifestations of recurrent fibrous dysplasia with an extensive affection of anthro maxillary, ethmoidal and sphenoid sinuses, in addition to orbitary and cranial base invasion.

  7. [About a case of calcifying fibrous tumor of the pleura].

    Science.gov (United States)

    Rocas, Delphine; Thivolet-Béjui, Françoise; Tronc, François; Chalabreysse, Lara

    2015-12-01

    Calcifying fibrous tumor is a rare soft tissue benign tumor (OMS 2002). Some pleural localisations are described, which affect slightly older individuals than the other soft tissue forms. The calcifying fibrous tumor is included in the 2004 World Health Organization classification of pleural tumors. A pleural tumor located in the right inferior pulmonary lobe is diagnosed in a 59-year-old man. This pleural tumor is macroscopically well-circumscribed. Histologically, the rare spindle tumoral cells are located between bundles of a collagenous tissue, sometimes hyalinized, with psammomatous or dystrophic calcifications. The tumoral cells have a fibrohistiocytic origin. They stain positively for antibodies against vimentin, factor XIIIa, CD68, CD163, CD34. Antibodies against smooth muscle actin, desmin, PS100, ALK1 and EBV are negative. Main differencial diagnoses are other benign pleural tumors (solitary fibrous tumor, inflammatory myofibroblastique tumor), some malignant tumors (desmoplastic malignant pleural mesothelioma) and pleural pseudotumors (calcified pleural plaques, chronic fibrous pleuritis, amylose, hyalinizing granuloma). Our case is the 15th pleural calcifying fibrous tumor being reported. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  8. Computed tomographic features of fibrous dysplasia of maxillofacial region

    Energy Technology Data Exchange (ETDEWEB)

    Sontakke, Subodh Arun; Karjodka, Freny R [Nair Hospital Dental College, Mumba (India); Umarji, Hemant R [Government Dental College and Hospital, Mumbai (India)

    2011-03-15

    This study was to find the computed tomographic features of fibrous dysplasia of the maxillofacial region. All eight cases included in the study reported either to Government Dental College and Hospital or Nair Hospital Dental College, Mumbai between 2003 and 2009. The patients were prescribed computed tomogram in addition to conventional radiographs of maxillofacial region which were studied for characteristic features of fibrous dysplasia. The diagnosis of fibrous dysplasia was confirmed by histopathological report. All cases showed the ill-defined margins of lesions except in the region where the lesions were extending to cortex of the involved bone. Internal structure of all cases showed ground glass appearance. Four cases of maxillary lesion showed the displacement of maxillary sinus maintaining the shape of maxillary sinus. Two cases showed complete obliteration of maxillary sinus. Displacement of inferior alveolar canal did not follow any typical pattern in any of the cases but was displaced in different directions. The craniofacial type of fibrous dysplasia is as common as fibrous dysplasia of jaw. The margins, extent, internal structure and effect on surrounding structure are well detected on computed tomographic images.

  9. Ecophysiology of stromatolitic microbial mats, Stocking Island, exuma cays, Bahamas.

    Science.gov (United States)

    Pinckney, J; Paerl, H W; Reid, R P; Bebout, B

    1995-01-01

    Intertidal stromatolites, covered by cyanobacterial mats, were recently discovered at Stocking Island, Exuma Cays, Bahamas. Ecophysiological responses (CO2 fixation, N2 fixation, and photoacclimation) of these cyanobacterial mats to experimental manipulations were examined to identify potential environmental variables controlling community structure and function. The mats exhibit horizontal zonation that shifts from soft to crusty to hard in a seaward direction. Cluster analysis of chemotaxonomic photopigments (chlorophylls and carotenoids) revealed that visually distinct mat types are composed of distinct phototrophic assemblages. Under reduced irradiance, diatoms within the mats photoacclimated by increasing accessory photopigments (diadinoxanthin, fucoxanthin, and chlorophyll c 1 c 2) and cyanobacteria reduced the photoprotective carotenoid echinenone. In a 4-day nutrient addition bioassay experiment, nitrate, phosphate, dissolved organic carbon, and trace metal enrichments did not enhance CO2 fixation, but phosphate enrichments tripled N2 fixation rates. The addition of DCMU increased N2 fixation rates relative to nonamended light and dark rates, indicating light (photosystem I) enhanced nitrogenase activity. Soft mats appear to represent the early stages of colonization and stabilization of mat communities. Active growth following stabilization results in the formation of partially-lithified crusty mats, which eventually become highly-lithified and form hard mats. Collectively, our results suggest that Stocking Island stromatolitic mats have low growth rates and consequently exhibit slow responses to increased nutrient availability and changes in ambient irradiance. In general, intertidal stromatolitic mats at Stocking Island appear to exhibit low rates of CO2 and N2 fixation relative to nonlithifying temperate cyanobacteral mats. Although production is low, respiration is likewise low, leading to the suggestion that high production to respiration ratios (P

  10. Radiological analysis of polyostotic fibrous dysplasia in skeletal system

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Ma Rie; Kim, Jin Sik; Kim, Han Suk [National Medical Center, Seoul (Korea, Republic of); Park, Soo Soung [Chung Ang University College of Medicine, Seoul (Korea, Republic of)

    1984-12-15

    Over a period of recent 3 years, the 5 cases of polyostotic fibrous dysplasia were proven histologically at National Medical Center, and they were evaluated and analyzed radiologically and clinically. The results were as follows: 1. The age of 5 patients ranged from 12 to 21. 2. In general, clinical symptoms of these patients were pain of affected sites and swelling , fracture, walking disturbance of lower extremities. 3. The order of frequent site of polyostotic fibrous dysplasia was skull (4 cases), femur (3 cases), maxilla (2 case), humerus, tibia, rib, radius, metacarpal bone and phalanx. 4. The characteristic radiological findings of polyostotic fibrous dysplasia were multicystic lesions with ground glass appearance, osteosclerosis, cortical thinning and pathologic fracture and deformity of long bones. Particularly, in the extremities, multicystic radiolucencies, groud glass appearance, shepherd's crook and coxa vara deformities were noticed, and in the skull and maxilla, sclerotic changes were principally demonstrated.

  11. Polyostotic Fibrous Dysplasia of Cranio-Maxillofacial Area

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jin Woo; Kwon, Hyuk Rok; Lee, Jin Ho; Park, In Woo [Dept. of Oral and Maxillofacial Radiology, College of Dentistry, Kangnung National University, Kangnung (Korea, Republic of)

    2000-06-15

    Fibrous dysplasia is believed to be a hamartomatous developmental lesion of unknown origin. This disease is divided into monostotic and polyostotic fibrous dysplasia. Polyostotic type can be divided into craniofacial type, Lichtenstein-Jaffe type, and McCune-Albright syndrome. In this case, a 31-year-old female presented spontaneous loss of right mandibular teeth before 5 years and has shown continuous expansion of right mandibular alveolus. Through the radiographic view, the coarse pattern of the mixed radiopaque-lucent lesion was seen on the right mandibular body, and there was diffuse pattern of the mixed radiopaque-lucent lesion with ill-defined margin in the left mandibular body. In the right calvarium, the lesion had cotton-wool appearance. Partial excision for contouring, multiple extraction, and alveoloplasty were accomplished under general anesthesia for supportive treatment. Finally we could conclude this case was polyostotic fibrous dysplasia of cranio-maxillofacial area based on the clinical, radiologic finding, and histopathologic examination.

  12. 4D fibrous materials: characterising the deployment of paper architectures

    Science.gov (United States)

    Mulakkal, Manu C.; Seddon, Annela M.; Whittell, George; Manners, Ian; Trask, Richard S.

    2016-09-01

    Deployment of folded paper architecture using a fluid medium as the morphing stimulus presents a simple and inexpensive methodology capable of self-actuation; where the underlying principles can be translated to develop smart fibrous materials capable of programmable actuations. In this study we characterise different paper architectures and their stimuli mechanisms for folded deployment; including the influence of porosity, moisture, surfactant concentration, temperature, and hornification. We observe that actuation time decreases with paper grammage; through the addition of surfactants, and when the temperature is increased at the fluid-vapour interface. There is a clear effect of hydration, water transport and the interaction of hydrogen bonds within the fibrous architecture which drives the deployment of the folded regions. The importance of fibre volume fraction and functional fillers in shape recovery was also observed, as well as the effect of a multilayer composite paper system. The design guidelines shown here will inform the development of synthetic fibrous actuators for repeated deployment.

  13. Malign Fibrous Histiocytoma of the Bladder: A Rare Case Report

    Directory of Open Access Journals (Sweden)

    Ižbrahim Bozkurt

    2014-06-01

    Full Text Available Malignant fibrous histocytoma is a mesenchimal tumor, which was described in 1964. It is the most common soft tissue sarcoma in patients over the age of 40 years. There were very few reports about malignant fibrous histocytoma in urinary tract especially in bladder with 30 patients. Patients usually present with gross hematuria. Because of its agressive characteristics; recurrences, progressions and metastasis are likely. Tumor grade, tumor size, amount of invasion and histological type are the risk factors for metastasis. Early radical cystectomy is the first treatment option because of poor prognosis of these tumors but usually can not be sufficient. Chemotherapy and radiotherapy are used to as an alternative treatment or adjuvant treatment with surgery. We would like to present a bladder malignant fibrous histocytoma case to contribute to the lirature.

  14. Malignant fibrous histiocytoma of colon: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Hwan; Jee, Keum Nahn [Dankook University College of Medicine, Cheonan (Korea, Republic of)

    2006-03-15

    Gastrointestinal malignant fibrous histiocytomas (MFH) are very rare and only about 30 cases have been reported in the English literature, among which 20 cases were from colorectal MFHs. A small bowel MFH with intussusception has been the only reported case in the Korean medical literature. A 52-year-old male presented with complaints of recently developed and aggravated right upper abdominal pain. We present the CT appearance and the clinico-pathologic findings of his primary inflammatory malignant fibrous histiocytoma, which arose from the subserosal layer of the ascending colon with tumor infiltration in all the layers. The colon showed extensive hemorrhagic necrosis and repetitive multifocal microperforations with resultant panperitonitis.

  15. Focal electroencephalography rhythm asymmetry due to focal skull fibrous dysplasia

    Directory of Open Access Journals (Sweden)

    Michael A. Meyer

    2014-06-01

    Full Text Available An unusual pervasive and persistent asymmetry in background rhythm was found on surface electroencephalography (EEG recordings in a 22 year old with new onset of generalized seizure activity. Radiographic correlation with computed tomography, positron emission tomography and bone scan imaging uncovered that the higher amplitude left frontal-parietal background activity was related to a circumscribed area of left frontal-parietal fibrous dysplasia affecting the skull. This case report emphasizes that the presumed higher electrical conductance of fibrous dysplasia lead to a greater transparency of normal background rhythms, and must be taken into account as a form of breach rhythm for accurate EEG interpretation.

  16. Fibrous dysplasia localized to spine: a diagnostic dilemma

    Energy Technology Data Exchange (ETDEWEB)

    Gogia, Nidhi; Gulati, Manpreet [All India Institute of Medical Sciences, Department of Radiology, New Delhi (India); Marwaha, V. [All India Institute of Medical Sciences, Department of Radiology, New Delhi (India); All India Institute of Medical Sciences, Department of Medicine, New Delhi (India); Atri, S. [All India Institute of Medical Sciences, Department of Pathology, New Delhi (India); Gupta, Rajiva [All India Institute of Medical Sciences Ansari Nagar, Department of Medicine, Division of Rheumatology and Clinical Immunology, New Delhi (India)

    2007-06-15

    Fibrous dysplasia of the spine is uncommon, especially in monostotic form. Isolated vertebral involvement in polyostotic form is very rare. We report a case of polyostotic fibrous dysplasia with lesions localized to dorso-lumbar spine in a 45-year-old rheumatoid arthritis patient. No associated appendicular lesions, cutaneous manifestations or endocrinopathies were seen. The extreme rarity of this type of lesion can pose a diagnostic dilemma, and biopsy is required for diagnosis. The association with rheumatoid arthritis in our case seems to be a chance occurrence. (orig.)

  17. Non-steady-state aerosol filtration in nanostructured fibrous media.

    Science.gov (United States)

    Przekop, Rafal; Gradoń, Leon

    2011-06-28

    The filtration of aerosol particles using composites of nano- and microsized fibrous structures is a promising method for the effective separation of nanoparticles from gases. A multi-scale physical system describing the flow pattern and particle deposition at a non-steady-state condition requires an advanced method of modelling. The combination of lattice Boltzmann and Brownian dynamics was used for analysis of the particle deposition pattern in a fibrous system. The dendritic structures of deposits for neutral and charged fibres and particles are present. The efficiency of deposition, deposit morphology, porosity and fractal dimension were calculated for a selected operational condition of the process.

  18. Under Ground Cable Sizing Using MAT LAB

    Directory of Open Access Journals (Sweden)

    B. V. R. Uday Kiran

    2014-06-01

    Full Text Available The main theme of this paper is to explain the procedure to calculate the cross sectional area of a conductor of an underground cable for a specified power & voltage ratings. This paper will also explain one of the simplest ways to calculate the cross section. In this paper we analyzed various factors that effect in deciding the ampacity of the conductor. We developed a Mat lab code to find the cross sectional area by including some of the parameters and also the voltage drop , maximum permissible voltage drop for that size of the conductor and also the number of runs of the cable that are to be laid.

  19. Contributions of ectomycorrhizal fungal mats to forest soil respiration

    Science.gov (United States)

    C. Phillips; L.A. Kluber; J.P. Martin; B.A. Caldwell; B.J. Bond

    2012-01-01

    Distinct aggregations of fungal hyphae and rhizomorphs, or “mats”, formed by some genera of ectomycorrhizal (EcM) fungi are common features of soils in coniferous forests of the Pacific Northwest. We measured in situ respiration rates of Piloderma mats and neighboring non-mat soils in an old-growth Douglas-fir forest in western Oregon to investigate whether there was...

  20. Mats Reidius : Rootsi taluliit tahab üle minna eurole / Mats Reidius ; interv. Annika Poldre

    Index Scriptorium Estoniae

    Reidius, Mats

    2003-01-01

    Rootsi majandusteadlane Mats Reidius Rootsi põllumajanduse olukorrast enne Rootsi liitumist EL-iga, Rootsi talunike võitudest-kaotustest El-iga ühinemisel, muutustest Rootsi toiduaineturul pärast EL-iga liitumist, Rootsi talunike arvamusest euro kohta

  1. Mats Reidius : Rootsi taluliit tahab üle minna eurole / Mats Reidius ; interv. Annika Poldre

    Index Scriptorium Estoniae

    Reidius, Mats

    2003-01-01

    Rootsi majandusteadlane Mats Reidius Rootsi põllumajanduse olukorrast enne Rootsi liitumist EL-iga, Rootsi talunike võitudest-kaotustest El-iga ühinemisel, muutustest Rootsi toiduaineturul pärast EL-iga liitumist, Rootsi talunike arvamusest euro kohta

  2. Laser Printing of Superhydrophobic Patterns from Mixtures of Hydrophobic Silica Nanoparticles and Toner Powder

    Science.gov (United States)

    Ngo, Chi-Vinh; Chun, Doo-Man

    2016-11-01

    In this work, a new and facile dry printing method was developed for the direct fabrication of superhydrophobic patterns based on silica nanoparticles. Mixtures of hydrophobic fumed silica nanoparticles and toner powder were printed on paper and polymer sheets using a commercial laser printer to produce the superhydrophobic patterns. The mixing ratio of the toner powder (for the laser printer) to hydrophobic silica was also investigated to optimize both the printing quality and the superhydrophobicity of the printed areas. The proper mixing ratio was then used to print various superhydrophobic patterns, including triangular, square, circular, and complex arrangements, to demonstrate that superhydrophobic surfaces with different patterns can be fabricated in a few seconds without any post-processing. The superhydrophobicity of each sample was evaluated by contact angle measurements, and all printed areas showed contact angles greater than 150°. The research described here opens the possibility of rapid production of superhydrophobic surfaces with various patterns. Ultimately, the obtained findings may have a significant impact on applications related to self-cleaning, control of water geometry and position, fluid mixing and fluid transport.

  3. Laser Printing of Superhydrophobic Patterns from Mixtures of Hydrophobic Silica Nanoparticles and Toner Powder.

    Science.gov (United States)

    Ngo, Chi-Vinh; Chun, Doo-Man

    2016-11-08

    In this work, a new and facile dry printing method was developed for the direct fabrication of superhydrophobic patterns based on silica nanoparticles. Mixtures of hydrophobic fumed silica nanoparticles and toner powder were printed on paper and polymer sheets using a commercial laser printer to produce the superhydrophobic patterns. The mixing ratio of the toner powder (for the laser printer) to hydrophobic silica was also investigated to optimize both the printing quality and the superhydrophobicity of the printed areas. The proper mixing ratio was then used to print various superhydrophobic patterns, including triangular, square, circular, and complex arrangements, to demonstrate that superhydrophobic surfaces with different patterns can be fabricated in a few seconds without any post-processing. The superhydrophobicity of each sample was evaluated by contact angle measurements, and all printed areas showed contact angles greater than 150°. The research described here opens the possibility of rapid production of superhydrophobic surfaces with various patterns. Ultimately, the obtained findings may have a significant impact on applications related to self-cleaning, control of water geometry and position, fluid mixing and fluid transport.

  4. A facile electrodeposition process to fabricate corrosion-resistant superhydrophobic surface on carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Yi [State Key Lab of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), Rd. 8, Xindu District, Chengdu City, Sichuan Province 610500 (China); School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu City, Sichuan Province 610500 (China); He, Yi, E-mail: chemheyi@swpu.edu.cn [State Key Lab of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), Rd. 8, Xindu District, Chengdu City, Sichuan Province 610500 (China); School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu City, Sichuan Province 610500 (China); Luo, Pingya, E-mail: luopy@swpu.edu.cn [State Key Lab of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), Rd. 8, Xindu District, Chengdu City, Sichuan Province 610500 (China); Chen, Xi; Liu, Bo [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu City, Sichuan Province 610500 (China)

    2016-04-15

    Graphical abstract: - Highlights: • A facile fabrication of superhydrophobic film was obtained on carbon steel. • Composition of superhydrophobic film is iron palmitate. • The film exhibits excellent chemical stability and good self-cleaning effect. • Corrosion of C45 steel is significantly inhibited with superhydrophobic surface. - Abstract: Superhydrophobic Fe film with hierarchical micro/nano papillae structures is prepared on C45 steel surface by one-step electrochemical method. The superhydrophobic surface was measured with a water contact angle of 160.5 ± 0.5° and a sliding angle of 2 ± 0.5°. The morphology of the fabricated surface film was characterized by field emission scanning electron microscopy (FE-SEM), and the surface structure seems like accumulated hierarchical micro-nano scaled particles. Furthermore, according to the results of Fourier transform infrared spectra (FT-IR) and X-ray photoelectron spectroscopy (XPS), the chemical composition of surface film was iron complex with organic acid. Besides, the electrochemical measurements showed that the superhydrophobic surface improved the corrosion resistance of carbon steel in 3.5 wt.% NaCl solution significantly. The superhydrophobic layer can perform as a barrier and provide a stable air–liquid interface which inhibit penetration of corrosive medium. In addition, the as-prepared steel exhibited an excellent self-cleaning ability that was not favor to the accumulation of contaminants.

  5. Nearly Perfect Durable Superhydrophobic Surfaces Fabricated by a Simple One-Step Plasma Treatment.

    Science.gov (United States)

    Ryu, Jeongeun; Kim, Kiwoong; Park, JooYoung; Hwang, Bae Geun; Ko, YoungChul; Kim, HyunJoo; Han, JeongSu; Seo, EungRyeol; Park, YongJong; Lee, Sang Joon

    2017-05-16

    Fabrication of superhydrophobic surfaces is an area of great interest because it can be applicable to various engineering fields. A simple, safe and inexpensive fabrication process is required to fabricate applicable superhydrophobic surfaces. In this study, we developed a facile fabrication method of nearly perfect superhydrophobic surfaces through plasma treatment with argon and oxygen gases. A polytetrafluoroethylene (PTFE) sheet was selected as a substrate material. We optimized the fabrication parameters to produce superhydrophobic surfaces of superior performance using the Taguchi method. The contact angle of the pristine PTFE surface is approximately 111.0° ± 2.4°, with a sliding angle of 12.3° ± 6.4°. After the plasma treatment, nano-sized spherical tips, which looked like crown-structures, were created. This PTFE sheet exhibits the maximum contact angle of 178.9°, with a sliding angle less than 1°. As a result, this superhydrophobic surface requires a small external force to detach water droplets dripped on the surface. The contact angle of the fabricated superhydrophobic surface is almost retained, even after performing an air-aging test for 80 days and a droplet impacting test for 6 h. This fabrication method can provide superb superhydrophobic surface using simple one-step plasma etching.

  6. Durability of the tunable adhesive superhydrophobic PTFE surfaces for harsh environment applications

    Science.gov (United States)

    Fang, Yao; Yong, Jiale; Chen, Feng; Huo, Jinglan; Yang, Qing; Bian, Hao; Du, Guangqing; Hou, Xun

    2016-09-01

    Tunable adhesive superhydrophobic materials have attracted increasing research interest due to their applications in microdroplet manipulation, biological detection and microfluidic system. However, most of the artificial materials easily lose superhydrophobicity in harsh environments. The durability of superhydrophobic materials is very important to extend their lifetime in practical applications. In this paper, bioinspired durable superhydrophobicity with tunable adhesion on polytetrafluoroethylene surfaces is realized via a one-step femtosecond laser irradiation. On the laser-induced superhydrophobic surfaces, the sliding angle can be tuned from 1° to 90° (water droplet is pinned on the surface at any titled angles). The tunable water adhesion results from different contact states which change from the lotus state to the transition state and then to the composite state with increasing average distance of irradiation points. Water droplet quick localization and no-loss droplet transportation were achieved through designing surface adhesion. In addition, the resultant surfaces are so stable that they can maintain superhydrophobicity even after storing in harsh environments, without dramatical superhydrophobicity decay for a long time.

  7. An improved Bayesian matting method based on image statistic characteristics

    Science.gov (United States)

    Sun, Wei; Luo, Siwei; Wu, Lina

    2015-03-01

    Image matting is an important task in image and video editing and has been studied for more than 30 years. In this paper we propose an improved interactive matting method. Starting from a coarse user-guided trimap, we first perform a color estimation based on texture and color information and use the result to refine the original trimap. Then with the new trimap, we apply soft matting process which is improved Bayesian matting with smoothness constraints. Experimental results on natural image show that this method is useful, especially for the images have similar texture feature in the background or the images which is hard to give a precise trimap.

  8. Pigment profiles and bacterial communities from Thailand thermal mats.

    Science.gov (United States)

    Portillo, M C; Sririn, V; Kanoksilapatham, W; Gonzalez, J M

    2009-11-01

    Differently colored layers of freshwater hot spring mats at Boekleung (Western Thailand) were studied. Temperatures ranged from over 50 up to 57 degrees C. Two mats were characterized: a laminated mat with a green and a red layers, and a monolayer, greenish-yellow mat. Bacterial communities in green, red, and yellow layers were investigated using molecular, culturing and pigment analysis methods. Pigment profiles covered a wide spectrum from chlorophylls to carotenoids. A green mat layer showed higher relative content of chlorophyll than yellow and red layers which presented higher proportion of carotenoids. Cyanobacterial isolates grow up to 55-56 degrees C and their pigment profiles showed a relatively high content of chlorophylls suggesting the importance of other bacterial groups in the mat pigment profiles. Bacterial communities were analyzed by 16S rDNA surveys showing Cyanobacteria and Chloroflexi as the mayor components of the community. Other significant members were Candidate Division OP10, Bacteroidetes, Planctomycetes and Actinobacteria. These results highlight a major participation of Cyanobacteria and Chloroflexi in thermal mat communities, and the preferential presence of Candidate Division OP10 in green mat layers. Differently colored mat layers showed characteristic bacterial communities which could be discriminated from pigment profiles and molecular surveys.

  9. Use of palm-mat geotextiles for rainsplash erosion control

    Science.gov (United States)

    Bhattacharyya, R.; Fullen, M. A.; Davies, K.; Booth, C. A.

    2010-07-01

    Soil detachment by raindrop action (rainsplash erosion) is a very important subprocess of erosion by water. It is a particular problem in the UK as most soils are sandy or loamy sand in texture and lands have gentle to medium slope. However, few studies report potential rainsplash erosion control options under field conditions. Hence, the utilization of palm-mat geotextiles as a rainsplash erosion control technique was investigated at Hilton, east Shropshire, U.K. (52°33'5.7″ N, 2°19'18.3″ W). Geotextile-mats constructed from Borassus aethiopum (Borassus palm of West Africa) and Mauritia flexuosa (Buriti palm of South America) leaves are termed Borassus mats and Buriti mats, respectively. Two-year field experiments were conducted at Hilton to study the effects of emplacing Borassus and Buriti mats on rainsplash erosion of a loamy sand soil. Two sets (12 plots each) of experiments were established to study the effects of these mats on splash height and splash erosion. Splash height needs to be known to assess the transport mechanism of major soil fraction and its constituents on sloping land by rainsplash. In both sets, six randomly-selected plots were covered with mats, and the rest were bare. Results (during 22/01/2007‒23/01/2009; total precipitation = 1731.5 mm) show that Borassus mat-covered plots had ˜ 89% ( P 0.05) effect in rainsplash erosion control during that period, although plots with Buriti mats significantly ( P 0.05) improve selected soil properties (i.e., soil organic matter, particle size distribution, aggregate stability and total soil carbon) as soil organic matter (SOM) input from mat-decomposition was much less than total SOM content. However, the changes in fine and medium sand contents (after 2 years) in the Borassus covered plots were significantly ( P < 0.05; n = 6) related to the total rainsplash erosion during 2007‒2009. Emplacement of Borassus and Buriti mats on bare soils did not decrease SOM contents after 2 years, indicating

  10. New universal matK primers for DNA barcoding angiosperms

    Institute of Scientific and Technical Information of China (English)

    Jing YU; Jian-Hua XUE; Shi-Liang ZHOU

    2011-01-01

    The chloroplast maturase K gene (matK) is one of the most variable coding genes of angiosperms and has been suggested to be a "barcode" for land plants. However, matK exhibits low amplification and sequencing rates due to low universality of currently available primers and mononucleotide repeats. To resolve these technical problems, we evaluated the entire matK region to find a region of 600-800 bp that is highly variable, represents the best of all matK regions with priming sites conservative enough to design universal primers, and avoids the mononucleotide repeats. After careful evaluation, a region in the middle was chosen and a pair of primers named natK472F and matK1248R was designed to amplify and sequence the matK fragment of approximately 776 bp. This region encompasses the most variable sites, represents the entire matK region best, and also exhibits high amplification rates and quality of sequences. The universality of this primer pair was tested using 58 species from 47 families of angiosperm plants. The primers showed a strong amplification (93.1%) and sequencing (92.6%)successes in the species tested. We propose that the new primers will solve, in part, the problems encountered when using matK and promote the adoption of matK as a DNA barcode for angiosperms.

  11. Allelopathy-mediated competition in microbial mats from Antarctic lakes.

    Science.gov (United States)

    Slattery, Marc; Lesser, Michael P

    2017-05-01

    Microbial mats are vertically stratified communities that host a complex consortium of microorganisms, dominated by cyanobacteria, which compete for available nutrients and environmental niches, within these extreme habitats. The Antarctic Dry Valleys near McMurdo Sound include a series of lakes within the drainage basin that are bisected by glacial traverses. These lakes are traditionally independent, but recent increases in glacial melting have allowed two lakes (Chad and Hoare) to become connected by a meltwater stream. Microbial mats were collected from these lakes, and cultured under identical conditions at the McMurdo Station laboratory. Replicate pairings of the microbial mats exhibited consistent patterns of growth inhibition indicative of competitive dominance. Natural products were extracted from the microbial mats, and a disk diffusion assay was utilized to show that allelochemical compounds mediate competitive interactions. Both microscopy and 16S rRNA sequencing show that these mats contain significant populations of cyanobacteria known to produce allelochemicals. Two compounds were isolated from these microbial mats that might be important in the chemical ecology of these psychrophiles. In other disk:mat pairings, including extract versus mat of origin, the allelochemicals exhibited no effect. Taken together, these results indicate that Antarctic lake microbial mats can compete via allelopathy. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. Fibrous dysplasia of the jaws associated with secondary hyperparathyroidism: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Whi, Jung Hyun; Kim, Young Joo; Chun, Kyung Ah; Kim, Ki Tae; Chang, Eun Deok; Kim, Young Ok; Lee, Won [The Catholic University of Korea, Uijongbu (Korea, Republic of)

    2007-06-15

    There have been few reports on fibrous dyplasia associated with secondary hyperparathyroidism. We report a case of a hemodialysis patient with secondary hyperparathyroidism concomitant with fibrous dysplasia of the jaws causing an abnormal deformity.

  13. Filtration efficiency of an electrostatic fibrous filter: Studying filtration dependency on ultrafine particle exposure and composition

    DEFF Research Database (Denmark)

    Ardkapan, Siamak Rahimi; Johnson, Matthew S.; Yazdi, Sadegh

    2014-01-01

    The objective of the present study is to investigate the relationship between ultrafine particle concentrations and removal efficiencies for an electrostatic fibrous filter in a laboratory environment. Electrostatic fibrous filters capture particles efficiently, with a low pressure drop. Therefor...

  14. Malignant fibrous histiocytoma of the colon. Report of the case and review of the subject.

    Science.gov (United States)

    Baltaziak, M; Zimnoch, L; Sobaniec-Lotowska, M; Kemona, A; Dziecioł, J

    1993-01-01

    Primary and metastatic malignant fibrous histiocytoma of the alimentary tract is uncommon, even though it is the most frequently diagnosed malignant soft tissue tumor in adults. In this report, we describe a case of malignant fibrous histiocytoma of the colon.

  15. Anti-icing properties of superhydrophobic ZnO/PDMS composite coating

    Science.gov (United States)

    Yang, Chao; Wang, Fajun; Li, Wen; Ou, Junfei; Li, Changquan; Amirfazli, Alidad

    2016-01-01

    We present the excellent anti-icing performance for a superhydrophobic coating surface based on ZnO/polydimethylsiloxane (ZnO/PDMS) composite. The superhydrophobic ZnO/PDMS coating surface was prepared by a facile solution mixing, drop coating, room-temperature curing and surface abrading procedure. The superhydrophobic ZnO/PDMS composite coating possesses a water contact angle of 159.5° and a water sliding angle of 8.3° at room temperature (5 °C). The anti-icing properties of the superhydrophobic coating were investigated by continuously dropping cold-water droplets (about 0 °C) onto the pre-cooled surface using a home-made apparatus. The sample was placed at different tilting angle (0° and 10°) and pre-cooled to various temperatures (-5, -10 and -15 °C) prior to measure. The pure Al surface was also studied for comparison. It was found that icing accretion on the surface could be reduced apparently because the water droplets merged together and slid away from the superhydrophobic surface at all of the measuring temperatures when the surface is horizontally placed. In addition, water droplet slid away completely from the superhydrophobic surface at -5 and -10 °C when the surface is tilted at 10°, which demonstrates its excellent anti-icing properties at these temperatures. When the temperature decreased to -15 °C, though ice accretion on the tilted superhydrophobic coating surface could not be avoided absolutely, the amount of ice formed on the surface is very small, which indicated that the coating surface with superhydrophobicity could significantly reduce ice accumulation on the surface at very low temperature (-15 °C). Importantly, the sample is also stable against repeated icing/deicing cycles. More meaningfully, once the superhydrophobic surface is damaged, it can be repaired easily and rapidly.

  16. Electric-field-enhanced condensation on superhydrophobic nanostructured surfaces.

    Science.gov (United States)

    Miljkovic, Nenad; Preston, Daniel J; Enright, Ryan; Wang, Evelyn N

    2013-12-23

    When condensed droplets coalesce on a superhydrophobic nanostructured surface, the resulting droplet can jump due to the conversion of excess surface energy into kinetic energy. This phenomenon has been shown to enhance condensation heat transfer by up to 30% compared to state-of-the-art dropwise condensing surfaces. However, after the droplets jump away from the surface, the existence of the vapor flow toward the condensing surface increases the drag on the jumping droplets, which can lead to complete droplet reversal and return to the surface. This effect limits the possible heat transfer enhancement because larger droplets form upon droplet return to the surface, which impedes heat transfer until they can be either removed by jumping again or finally shedding via gravity. By characterizing individual droplet trajectories during condensation on superhydrophobic nanostructured copper oxide (CuO) surfaces, we show that this vapor flow entrainment dominates droplet motion for droplets smaller than R ≈ 30 μm at moderate heat fluxes (q″ > 2 W/cm(2)). Subsequently, we demonstrate electric-field-enhanced condensation, whereby an externally applied electric field prevents jumping droplet return. This concept leverages our recent insight that these droplets gain a net positive charge due to charge separation of the electric double layer at the hydrophobic coating. As a result, with scalable superhydrophobic CuO surfaces, we experimentally demonstrated a 50% higher overall condensation heat transfer coefficient compared to that on a jumping-droplet surface with no applied field for low supersaturations (condensation heat transfer enhancement but also offers avenues for improving the performance of self-cleaning and anti-icing surfaces as well as thermal diodes.

  17. Robust Cassie state of wetting in transparent superhydrophobic coatings.

    Science.gov (United States)

    Tuvshindorj, Urandelger; Yildirim, Adem; Ozturk, Fahri Emre; Bayindir, Mehmet

    2014-06-25

    This paper investigates the stability of the Cassie state of wetting in transparent superhydrophobic coatings by comparing a single-layer microporous coating with a double-layer micro/nanoporous coating. Increasing pressure resistance of superhydrophobic coatings is of interest for practical use because high external pressures may be exerted on surfaces during operation. The Cassie state stability against the external pressure of coatings was investigated by squeezing droplets sitting on surfaces with a hydrophobic plate. Droplets on the single-layer coating transformed to the Wenzel state and pinned to the surface after squeezing, whereas droplets on the double-layer micro/nanoporous coating preserved the Cassie state and rolled off the surface easily. In addition, the contact angle and contact-line diameter of water droplets during evaporation from surfaces were in situ investigated to further understand the stability of coatings against Wenzel transition. A droplet on a microporous coating gradually transformed to the Wenzel state and lost its spherical shape as the droplet volume decreased (i.e., the internal pressure of the droplet increased). The contact line of the droplet during evaporation remained almost unchanged. In contrast, a water droplet on a double-layer surface preserved its spherical shape even at the last stages of the evaporation process, where pressure differences as high as a few thousand pascals were generated. For this case, the droplet contact line retracted during evaporation and the droplet recovered the initial water contact angle. The demonstrated method for the preparation of robust transparent superhydrophobic coatings is promising for outdoor applications such as self-cleaning cover glasses for solar cells and nonwetting windows.

  18. Stabilization of Leidenfrost vapour layer by textured superhydrophobic surfaces.

    Science.gov (United States)

    Vakarelski, Ivan U; Patankar, Neelesh A; Marston, Jeremy O; Chan, Derek Y C; Thoroddsen, Sigurdur T

    2012-09-13

    In 1756, Leidenfrost observed that water drops skittered on a sufficiently hot skillet, owing to levitation by an evaporative vapour film. Such films are stable only when the hot surface is above a critical temperature, and are a central phenomenon in boiling. In this so-called Leidenfrost regime, the low thermal conductivity of the vapour layer inhibits heat transfer between the hot surface and the liquid. When the temperature of the cooling surface drops below the critical temperature, the vapour film collapses and the system enters a nucleate-boiling regime, which can result in vapour explosions that are particularly detrimental in certain contexts, such as in nuclear power plants. The presence of these vapour films can also reduce liquid-solid drag. Here we show how vapour film collapse can be completely suppressed at textured superhydrophobic surfaces. At a smooth hydrophobic surface, the vapour film still collapses on cooling, albeit at a reduced critical temperature, and the system switches explosively to nucleate boiling. In contrast, at textured, superhydrophobic surfaces, the vapour layer gradually relaxes until the surface is completely cooled, without exhibiting a nucleate-boiling phase. This result demonstrates that topological texture on superhydrophobic materials is critical in stabilizing the vapour layer and thus in controlling--by heat transfer--the liquid-gas phase transition at hot surfaces. This concept can potentially be applied to control other phase transitions, such as ice or frost formation, and to the design of low-drag surfaces at which the vapour phase is stabilized in the grooves of textures without heating.

  19. Shear driven droplet shedding and coalescence on a superhydrophobic surface

    Science.gov (United States)

    Moghtadernejad, S.; Tembely, M.; Jadidi, M.; Esmail, N.; Dolatabadi, A.

    2015-03-01

    The interest on shedding and coalescence of sessile droplets arises from the importance of these phenomena in various scientific problems and industrial applications such as ice formation on wind turbine blades, power lines, nacelles, and aircraft wings. It is shown recently that one of the ways to reduce the probability of ice accretion on industrial components is using superhydrophobic coatings due to their low adhesion to water droplets. In this study, a combined experimental and numerical approach is used to investigate droplet shedding and coalescence phenomena under the influence of air shear flow on a superhydrophobic surface. Droplets with a size of 2 mm are subjected to various air speeds ranging from 5 to 90 m/s. A numerical simulation based on the Volume of Fluid method coupled with the Large Eddy Simulation turbulent model is carried out in conjunction with the validating experiments to shed more light on the coalescence of droplets and detachment phenomena through a detailed analysis of the aerodynamics forces and velocity vectors on the droplet and the streamlines around it. The results indicate a contrast in the mechanism of two-droplet coalescence and subsequent detachment with those related to the case of a single droplet shedding. At lower speeds, the two droplets coalesce by attracting each other with successive rebounds of the merged droplet on the substrate, while at higher speeds, the detachment occurs almost instantly after coalescence, with a detachment time decreasing exponentially with the air speed. It is shown that coalescence phenomenon assists droplet detachment from the superhydrophobic substrate at lower air speeds.

  20. Stabilization of Leidenfrost vapour layer by textured superhydrophobic surfaces

    KAUST Repository

    Vakarelski, Ivan Uriev

    2012-09-12

    In 1756, Leidenfrost observed that water drops skittered on a sufficiently hot skillet, owing to levitation by an evaporative vapour film. Such films are stable only when the hot surface is above a critical temperature, and are a central phenomenon in boiling. In this so-called Leidenfrost regime, the low thermal conductivity of the vapour layer inhibits heat transfer between the hot surface and the liquid. When the temperature of the cooling surface drops below the critical temperature, the vapour film collapses and the system enters a nucleate-boiling regime, which can result in vapour explosions that are particularly detrimental in certain contexts, such as in nuclear power plants. The presence of these vapour films can also reduce liquid-solid drag. Here we show how vapour film collapse can be completely suppressed at textured superhydrophobic surfaces. At a smooth hydrophobic surface, the vapour film still collapses on cooling, albeit at a reduced critical temperature, and the system switches explosively to nucleate boiling. In contrast, at textured, superhydrophobic surfaces, the vapour layer gradually relaxes until the surface is completely cooled, without exhibiting a nucleate-boiling phase. This result demonstrates that topological texture on superhydrophobic materials is critical in stabilizing the vapour layer and thus in controlling-by heat transfer-the liquid-gas phase transition at hot surfaces. This concept can potentially be applied to control other phase transitions, such as ice or frost formation, and to the design of low-drag surfaces at which the vapour phase is stabilized in the grooves of textures without heating. © 2012 Macmillan Publishers Limited. All rights reserved.

  1. Localized fibrous tumor of the liver: imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Lecesne, R.; Drouillard, J.; Laurent, F. [Service d`Imagerie Medicale-Radiologie Diagnostique et Therapeutique, Hopital du Haut-Leveque, CHU Bordeaux, Pessac (France); Le Bail, B. [Department d`Anatomie et Cytologie Pathologiques, Groupe Hospitalier Pellegrin, CHU Bordeaux, Place Amelie Raba-Leon, Bordeaux (France); Saric, J. [Service de Chirurgie Digestive, Groupe Saint-Andre, CHU Bordeaux (France); Balabaud, C. [Service des Maladies de L`Appareil Digestif, Groupe Saint-Andre, CHU Bordeaux (France)

    1998-02-01

    We report the imaging of a localized fibrous tumor of the liver, focusing on color Doppler US, CT, MR imaging, and angiographic findings. We discuss the differential diagnosis of such a rare, benign lesion of the liver. Detailed imaging of this tumor has not been reported in the literature previously. (orig.) With 6 figs., 10 refs.

  2. Use of Zoledronic Acid in Paediatric Craniofacial Fibrous Dysplasia

    Directory of Open Access Journals (Sweden)

    Chiara Di Pede

    2016-01-01

    Full Text Available We describe a case of a paediatric patient affected by mandibular fibrous dysplasia (FD with severe and chronic pain who was successfully treated with zoledronic acid (ZOL: a third-generation bisphosphonate. Further research is needed to assess its safety and efficacy as a treatment option for FD in the paediatric population.

  3. Imitation model of destruction of aviation fibrous polymeric composite materials

    Directory of Open Access Journals (Sweden)

    В. М. Синеглазов

    2000-12-01

    Full Text Available Considered are models imitating influence of lighting on dielectric construction materials with elements of lighting protection. Described are models of current spreading in multilayer materials and thermal destruction of fibrous polymeric composite materials caused by lighting current flowing on such materials

  4. Transarterial Onyx Embolization of an Orbital Solitary Fibrous Tumor

    Science.gov (United States)

    Hashemi, Nafiseh; Ling, Jeanie D.; Soparkar, Charles; Sami, Mirwat; Ellezam, Benjamin; Klucznik, Richard; Lee, Andrew G.; Chévez-Barrios, Patricia

    2015-01-01

    Solitary fibrous tumor (SFT) is an uncommon mesenchymal neoplasm sometimes found in the orbit. We report a case of an aggressive orbital SFT with enlarged feeding vessels that was successfully resected immediately after transarterial embolization with Onyx (ethylene vinyl alcohol copolymer). To our knowledge, this is the first report showing the histopathology of Onyx embolization material in an orbital SFT. PMID:27171911

  5. Compressibility of CNT-Grafted Fibrous Reinforcements: A Theory

    NARCIS (Netherlands)

    Lomov, S.V.; Koissin, V.; Karahan, M.; Godara, A.; Gorbatikh, L.; Verpoest, I.

    2010-01-01

    The paper introduces a theoretical model of compressibility of a nanotube forest with randomly oriented nanotubes, which is applied to predict compressibility of a fibrous reinforcement with CNT-grafted fibres. It is shown that the pressure needed to achieve the target fibre volume fraction of the p

  6. [Poliostotic fibrous dysplasia with affectation of cervical rachis].

    Science.gov (United States)

    Lumbreras, Ruth; Aznar, Jose María; Castro, Angel; Modrego, Francisco Javier; Ballester, Juan José; Espallargas, Teresa

    2007-01-01

    The fibrous dysplasia is a benign although progressive dysfunction, in which a gene mutation originates the production of fibrous disorganized bony matrix. The bony tissue is replaced by bony tissue in expansion (amorph conjuntival tissue) that produces bony deformities in some patients, pain, pathological fractures or deambulation disorders. The diagnosis is important since ocasionally the first symptom is the fracture. We show up the case of a 21 year-old patient with pain clinic in high cervical region. The complementary tests (radiology, bone scintigrraphy and MRI) and anatomo-pathology confirmed the diagnosis of polyostotic fibrous dysplasia with cranial (occipital, esfenoides and right frontal and temporal bone), iliac, femoral, tibial and cervical (apophysis of C2) affectation. Our attitude was of carrying out a narrow observation by means of periodical strict controls, advising to avoid hard activities or contact sports. To the five years the patient is free of symptomatology. Radiologically the injuries have been stabilized. The fibrous dysplasia can affect to a single bone (monostotic) or to several (polyostotic). In occasions it is associated to endocrine dysfunctions and skin pigmentations in McCune-Albright's syndrome. We confront a pathology that specifies an anatomo-pathologic diagnosis to be confirmed, an extension diagnosis to detect asymptomatic focuses and whose treatment is symptomatic in most of the cases only using surgery in frank deformities or when the fracture risk is considerable, although the recurrence is frequent. The malignization is exceptional but possible that's why continuous observation is needed. The radiation therapy is radically contraindicated.

  7. Solitary fibrous tumor of the thyroid with capsular invasion.

    Science.gov (United States)

    Bohórquez, Concepción Lara; González-Cámpora, Ricardo; Loscertales, Miguel Congregado; Escudero, Antonio García; Mezquita, Jesús Congregado

    2003-01-01

    This report describes the clinical and pathologic findings of a peculiar case of solitary fibrous tumor of the thyroid gland that showed capsular invasion. After four and a half years of follow-up, neither local recurrence nor metastasis has developed.

  8. Compressibility of CNT-Grafted Fibrous Reinforcements: A Theory

    NARCIS (Netherlands)

    Lomov, S.V.; Koysin, V.; Karahan, M.; Godara, A.; Gorbatikh, L.; Verpoest, I.

    2010-01-01

    The paper introduces a theoretical model of compressibility of a nanotube forest with randomly oriented nanotubes, which is applied to predict compressibility of a fibrous reinforcement with CNT-grafted fibres. It is shown that the pressure needed to achieve the target fibre volume fraction of the

  9. Pendant bubble method for an accurate characterization of superhydrophobic surfaces.

    Science.gov (United States)

    Ling, William Yeong Liang; Ng, Tuck Wah; Neild, Adrian

    2011-12-06

    The commonly used sessile drop method for measuring contact angles and surface tension suffers from errors on superhydrophobic surfaces. This occurs from unavoidable experimental error in determining the vertical location of the liquid-solid-vapor interface due to a camera's finite pixel resolution, thereby necessitating the development and application of subpixel algorithms. We demonstrate here the advantage of a pendant bubble in decreasing the resulting error prior to the application of additional algorithms. For sessile drops to attain an equivalent accuracy, the pixel count would have to be increased by 2 orders of magnitude.

  10. Self-Propelled Dropwise Condensate on Superhydrophobic Surfaces

    Science.gov (United States)

    Boreyko, Jonathan B.; Chen, Chuan-Hua

    2009-10-01

    In conventional dropwise condensation on a hydrophobic surface, the condensate drops must be removed by external forces for continuous operation. This Letter reports continuous dropwise condensation spontaneously occurring on a superhydrophobic surface without any external forces. The spontaneous drop removal results from the surface energy released upon drop coalescence, which leads to a surprising out-of-plane jumping motion of the coalesced drops at a speed as high as 1m/s. The jumping follows an inertial-capillary scaling and gives rise to a micrometric average diameter at steady state.

  11. Experimental research on friction-reduction with super-hydrophobic surfaces

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jia-peng; DU Xiang-dang; SHI Xiu-hua

    2007-01-01

    Many recent studies have confirmed the existence of liquid slip over particular types of solid surfaces, and these so-called super-hydrophobic surfaces have been shown to generate effective liquid slip because of the air trapped between the surface structures. In this paper, based on boundary layer theory, the microscopic structure of the super-hydrophobic surface is analyzed. The liquid slip effect on friction-reduction over super-hydrophobic surfaces under various flow conditions is investigated by experiments with a flume and water tunnel. The experimental results show that the greatest amount of drag-reduction that can be achieved is 8.76% at a low Re.

  12. Facile fabrication of iron-based superhydrophobic surfaces via electric corrosion without bath

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Qinghe [College of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116 (China); Liu, Hongtao, E-mail: liuht100@126.com [College of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116 (China); Chen, Tianchi [College of Mechanical & Electrical Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116 (China); Wei, Yan; Wei, Zhu [College of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116 (China)

    2016-04-30

    Graphical abstract: - Highlights: • This paper investigates the fabrication techniques towards superhydrophobic surface on carbon steel substrate via electric corrosion without a bath. • It has a vital significance to the industrialization of the fabrication of superhydrophobic surface on hard metal due to the advantages such as low cost, high efficiency, can be prepared in a large area, easy to construct in the field. • The preparation approach is so facile and time-saving that it delivers an opportunity to construct a superhydrophobic surface on carbon steel substrate and provides the feasibility for industrial application of superhydrophobic surface. • The as-prepared surface has many excellent properties, like low adhesive property, anti-corrosion ability, mechanical durability and anti-icing performance. - Abstract: Superhydrophobic surface is of wide application in the field of catalysis, lubrication, waterproof, biomedical materials, etc. The superhydrophobic surface based on hard metal is worth further study due to its advantages of high strength and wear resistance. This paper investigates the fabrication techniques towards superhydrophobic surface on carbon steel substrate via electric corrosion and studies the properties of as-prepared superhydrophobic surface. The hydrophobic properties were characterized by a water sliding angle (SA) and a water contact angle (CA) measured by the Surface tension instrument. A Scanning electron microscope was used to analyze the structure of the corrosion surface. The surface compositions were characterized by an Energy Dispersive Spectrum. The Electrochemical workstation was used to measure its anti-corrosion property. The anti-icing performance was characterized by a steam-freezing test in Environmental testing chamber. The SiC sandpaper and 500 g weight were used to test the friction property. The research result shows that the superhydrophobic surface can be successfully fabricated by electrocorrosion on

  13. A facile cost-effective method for preparing robust self-cleaning transparent superhydrophobic coating

    Science.gov (United States)

    Wang, Peng; Liu, Jie; Chang, Wenkai; Fan, Xiaoliang; Li, Chunyan; Shi, Yu

    2016-10-01

    This paper reports an easy method to prepare transparent superhydrophobic coating by two-step spray-coating method. In order to improve robustness, PDMS oligomers were used to bond the SiO2 nanoparticle/fluoroalkylsilane composite coating to the substrate. The transmittance of coated glass was above 80 % for wavelengths larger than 500 nm. Moreover, the prepared coating exhibited excellent self-cleaning properties in either air or oil environment. Furthermore, this coating retained superhydrophobic properties after three cycles of abrasion test or strong acid/base attack. Therefore, this robust self-cleaning transparent superhydrophobic coating may have a wide range of practical applications in the optical industry.

  14. High Stability Performance of Superhydrophobic Modified Fluorinated Graphene Films on Copper Alloy Substrates

    Directory of Open Access Journals (Sweden)

    Rafik Abbas

    2017-01-01

    Full Text Available A stable self-cleaning superhydrophobic modified fluorinated graphene surface with micro/nanostructure was successfully fabricated on copper substrates via drop coating process. Irregularly stacked island-like multilayered fluorinated graphene nanoflakes comprised the microstructure. The fabricated films exhibited outstanding superhydrophobic property with a water contact angle 167° and water sliding angle lower than 4°. The developed superhydrophobic surface showed excellent corrosion resistance with insignificant decrease of water contact angle 166° in 3.5 wt.% NaCl solution. This stable highly hydrophobic performance of the fluorinated graphene films could be useful in self-cleaning, antifogging, corrosion resistive coatings and microfluidic devices.

  15. Stable superhydrophobic surface: fabrication of interstitial cottonlike structure of copper nanocrystals by magnetron sputtering

    Directory of Open Access Journals (Sweden)

    Guoxing Li, Bo Wang, Yi Liu, Tian Tan, Xuemei Song, Er Li and Hui Yan

    2008-01-01

    Full Text Available A stable superhydrophobic copper surface was obtained by radio-frequency magnetic sputtering on Si (100 and quartz substrates. The water contact angle and sliding angle of the superhydrophobic copper surface were 160.5° and 3±1.9°, respectively. Scanning electron microscopy (SEM photos show that the superhydrophobic surface structure comprises many uniform nanocrystals with a diameter of about 100 nm. A brief explanation of the formation of this special microstructure and the mechanism of its wettability were proposed.

  16. Superhydrophobic copper surfaces fabricated by fatty acid soaps in aqueous solution for excellent corrosion resistance

    Science.gov (United States)

    Xu, Wenlong; Hu, Yuanyuan; Bao, Wenda; Xie, Xiaoyu; Liu, Yiran; Song, Aixin; Hao, Jingcheng

    2017-03-01

    A simple and safe one-step immersion method was developed to obtain the stable superhydrophobic copper surfaces with excellent corrosion resistance ability using fatty acids in water-medium instead of ethanol. An organic alkali, N,N-dimethylcyclohexylamine (DMCHA), was chosen to solve the poor solubility of fatty acids in water and the high Krafft point of carboxylate salts with inorganic counterions. The superhydrophobic property can be realized in a much quicker process (7.5 min) in aqueous solution than in ethanol (more than 2 d), which is universally feasible for the fabrication of superhydrophobic metal surfaces in industry scale, thereby greatly increasing the safety in industrial manufacture.

  17. Flow past superhydrophobic surfaces with cosine variation in local slip length

    CERN Document Server

    Asmolov, Evgeny S; Harting, Jens; Vinogradova, Olga I

    2012-01-01

    Anisotropic super-hydrophobic surfaces have the potential to greatly reduce drag and enhance mixing phenomena in microfluidic devices. Recent work has focused mostly on cases of super-hydrophobic stripes. Here, we analyze a relevant situation of cosine variation of the local slip length. We derive approximate formulae for maximal (longitudinal) and minimal (transverse) directional effective slip lengths that are in good agreement with the exact numerical solution and lattice-Bolzmann simulations for any surface slip fraction. The cosine texture can provide a very large effective (forward) slip, but it was found to be less efficient in generating a transverse flow as compared to super-hydrophobic stripes.

  18. Robust superhydrophobic surface on Al substrate with durability, corrosion resistance and ice-phobicity

    Science.gov (United States)

    Wang, Guoyong; Liu, Shuai; Wei, Sufeng; Liu, Yan; Lian, Jianshe; Jiang, Qing

    2016-02-01

    Practical application of superhydrophobic surfaces is limited by the fragility of nanoscale asperities. Combining chemical etching and anodization, microscale pits and nanoscale pores, instead of the micro and nano protrusions on traditional superhydrophobic surfaces mimicking Lutos leaves, were fabricated on commercially pure aluminum surfaces. After modified by FDTS, the surfaces were superhydrophobic and self-cleaning. The ultrahigh hardness and electrochemical stability of Al2O3 coating endowed the surface excellent mechanical durability and good corrosion resistance. Because the method is scalable, it may find practical application on body panels of automobiles and aircrafts and so on.

  19. Direct Numerical Simulation of Liquid Transport Through Fibrous Porous Media

    Science.gov (United States)

    Palakurthi, Nikhil Kumar

    Fluid flow through fibrous media occurs in many industrial processes, including, but not limited, to fuel cell technology, drug delivery patches, sanitary products, textile reinforcement, filtration, heat exchangers, and performance fabrics. Understanding the physical processes involved in fluid flow through fibrous media is essential for their characterization as well as for the optimization and development of new products. Macroscopic porous-media equations require constitutive relations, which account for the physical processes occurring at the micro-scale, to predict liquid transport at the macro-scale. In this study, micro-scale simulations were conducted using conventional computational fluid dynamics (CFD) technique (finite-volume method) to determine the macroscopic constitutive relations. The first part of this thesis deals with the single-phase flow in fibrous media, following which multi-phase flow through fibrous media was studied. Darcy permeability is an important parameter that characterizes creeping flow through a fibrous porous medium. It has a complex dependence on the medium's properties such as fibers' in-plane and through-plane orientation, diameter, aspect ratio, curvature, and porosity. A suite of 3D virtual fibrous structures with a wide range of geometric properties were constructed, and the permeability values of the structures were calculated by solving the 3D incompressible Navier-Stokes equations. The through-plane permeability was found to be a function of only the fiber diameter, the fibers' through-plane orientation, and the porosity of the medium. The numerical results were used to extend a permeability-porosity relation, developed in literature for 3D isotropic fibrous media, to a wide range of fibers' through-plane orientations. In applications where rate of capillary penetration is important, characterization of porous media usually involves determination of either the effective pore radius from capillary penetration experiments

  20. Restrictive lung disease and cor pulmonale secondary to polyostotic fibrous dysplasia.

    Science.gov (United States)

    Narayan, Rajeev L; Maldjian, Pierre D

    2009-01-09

    Polyostotic fibrous dysplasia is a rare benign pathological condition of bone in which proliferation of fibrous and osteoid elements results in expansile deformities of the skeleton. We present a case of polyostotic fibrous dysplasia in a young man in whom the severe deformities of the chest wall and spine produced restrictive lung disease, cor pulmonale and respiratory failure.

  1. The Ububele Baby Mat Service – A primary preventative mental ...

    African Journals Online (AJOL)

    ... by the Baby Mat practitioners in relation to culturally diverse understandings of ... The therapeutic couple engages with culturally-informed frames of reference in ... it was found to help those accessing the mat to find symbolic meaning in the ...

  2. Matting Of Hair Due To ′Sunsilk′ Shampoo

    Directory of Open Access Journals (Sweden)

    Nadeem Mohd

    1995-01-01

    Full Text Available Matting of hair been reported from time to time due to treatment of hair with detergent, shampoos, waving lotions, setting lotions and bleaches. A case of matting of hairs in a young girl due to a change in the brand of shampoo is reported.

  3. Matting of hair: what is the role of conditioners?

    Science.gov (United States)

    Rigopoulos, D; Kontochristopoulos, G; Kalogirou, O; Gregoriou, S; Katsambas, A

    2006-03-01

    Matting of the hair is a very rare and multifactorial condition affecting usually women. We present three female patients with matting of the hair as a result of the shampoo used. In all three cases, cutting of the affected hair was unavoidable.

  4. Chimie des matériaux hybrides

    OpenAIRE

    Sanchez, Clément

    2014-01-01

    Cours : chimie des matériaux hybrides Depuis plus d’une vingtaine d’années, les méthodes d’élaboration de nanomatériaux inorganiques ou hybrides reposant sur la « chimie douce » suscitent un très fort intérêt, aussi bien dans le monde universitaire qu’industriel. Ces méthodes de synthèse mettent en jeu des réactions de « polymérisation » au sens large s’effectuant à température ambiante, en solvant aqueux ou organique, à partir de précurseurs moléculaires ou nanoparticulaires. Ces conditions ...

  5. Durable superhydrophobic carbon soot coatings for sensor applications

    Science.gov (United States)

    Esmeryan, K. D.; Radeva, E. I.; Avramov, I. D.

    2016-01-01

    A novel approach for the fabrication of durable superhydrophobic (SH) carbon soot coatings used in quartz crystal microbalance (QCM) based gas or liquid sensors is reported. The method uses modification of the carbon soot through polymerization of hexamethyldisiloxane (HMDSO) by means of glow discharge RF plasma. The surface characterization shows a fractal-like network of carbon nanoparticles with diameter of ~50 nm. These particles form islands and cavities in the nanometer range, between which the plasma polymerized hexamethyldisiloxane (PPHMDSO) embeds and binds to the carbon chains and QCM surface. Such modified surface structure retains the hydrophobic nature of the soot and enhances its robustness upon water droplet interactions. Moreover, it significantly reduces the insertion loss and dynamic resistance of the QCM compared to the commonly used carbon soot/epoxy resin approach. Furthermore, the PPHMDSO/carbon soot coating demonstrates durability and no aging after more than 40 probing cycles in water based liquid environments. In addition, the surface layer keeps its superhydrophobicity even upon thermal annealing up to 540 °C. These experiments reveal an opportunity for the development of soot based SH QCMs with improved electrical characteristics, as required for high-resolution gas or liquid measurements.

  6. Fabrication of Bionic Superhydrophobic Manganese Oxide/Polystyrene Nanocomposite Coating

    Institute of Scientific and Technical Information of China (English)

    Xianghui Xu; Zhaozhu Zhang; Fang Guo; Jin Yang; Xiaotao Zhu; Xiaoyan Zhou; Qunji Xue

    2012-01-01

    A superhydrophobic manganese oxide/polystyrene (MnO2/PS) nanocomposite coating was fabricated by a facile spraying process.The mixture solution of MnO2/PS was poured into a spray gun,and then sprayed onto the copper substrate using 0.2 MPa nitrogen gas to construct superhydrophobic coating.The wettability of the composite coating was measured by sessile drop method.When the weight ratio of MnO2 to PS is 0.5:1,the maximum of contact angle (CA) (140°) is obtained at drying temperature of 180 ℃.As the content of MnO2 increases,the maximum of CA (155°) is achieved at 100 ℃.Surface morphologies and chemical composition were analyzed to understand the effect of the content of MnO2 nanorods and the drying temperature on CA.The results show that the wettability of the coating can be controlled by the content ofMnO2 nanorods and the drying temperature.Using the proposed method,the thickness of the coating can be controlled by the spraying times.If damaged,the coating can be repaired just by spraying the mixture solution again.

  7. Recent advances in the mechanical durability of superhydrophobic materials.

    Science.gov (United States)

    Milionis, Athanasios; Loth, Eric; Bayer, Ilker S

    2016-03-01

    Large majority of superhydrophobic surfaces have very limited mechanical wear robustness and long-term durability. This problem has restricted their utilization in commercial or industrial applications and resulted in extensive research efforts on improving resistance against various types of wear damage. In this review, advances and developments since 2011 in this field will be covered. As such, we summarize progress on fabrication, design and understanding of mechanically durable superhydrophobic surfaces. This includes an overview of recently published diagnostic techniques for probing and demonstrating tribo-mechanical durability against wear and abrasion as well as other effects such as solid/liquid spray or jet impact and underwater resistance. The review is organized in terms of various types of mechanical wear ranging from substrate adhesion, tangential surface abrasion, and dynamic impact to ultrasonic processing underwater. In each of these categories, we highlight the most successful approaches to produce robust surfaces that can maintain their non-wetting state after the wear or abrasive action. Finally, various recommendations for improvement of mechanical wear durability and its quantitative evaluation are discussed along with potential future directions towards more systematic testing methods which will also be acceptable for industry.

  8. Designing Self-Healing Superhydrophobic Surfaces with Exceptional Mechanical Durability.

    Science.gov (United States)

    Golovin, Kevin; Boban, Mathew; Mabry, Joseph M; Tuteja, Anish

    2017-03-29

    The past decade saw a drastic increase in the understanding and applications of superhydrophobic surfaces (SHSs). Water beads up and effortlessly rolls off a SHS due to its combination of low surface energy and texture. Whether being used for drag reduction, stain repellency, self-cleaning, fog harvesting, or heat transfer applications (to name a few), the durability of a SHS is critically important. Although a handful of purportedly durable SHSs have been reported, there are still no criteria available for systematically designing a durable SHS. In the first part of this work, we discuss two new design parameters that can be used to develop mechanically durable SHSs via the spray coating of different binders and fillers. These parameters aid in the rational selection of material components and allow one to predict the capillary resistance to wetting of any SHS from a simple topographical analysis. We show that not all combinations of sprayable components generate SHSs, and mechanically durable components do not necessarily generate mechanically durable SHSs. Moreover, even the most durable SHSs can eventually become damaged. In the second part, utilizing our new parameters, we design and fabricate physically and chemically self-healing SHSs. The most promising surface is fabricated from a fluorinated polyurethane elastomer (FPU) and the extremely hydrophobic small molecule 1H,1H,2H,2H-heptadecafluorodecyl polyhedral oligomeric silsesquioxane (F-POSS). A sprayed FPU/F-POSS surface can recover its superhydrophobicity even after being abraded, scratched, burned, plasma-cleaned, flattened, sonicated, and chemically attacked.

  9. Superhydrophobicity in perfection: the outstanding properties of the lotus leaf

    Directory of Open Access Journals (Sweden)

    Hans J. Ensikat

    2011-03-01

    Full Text Available Lotus leaves have become an icon for superhydrophobicity and self-cleaning surfaces, and have led to the concept of the ‘Lotus effect’. Although many other plants have superhydrophobic surfaces with almost similar contact angles, the lotus shows better stability and perfection of its water repellency. Here, we compare the relevant properties such as the micro- and nano-structure, the chemical composition of the waxes and the mechanical properties of lotus with its competitors. It soon becomes obvious that the upper epidermis of the lotus leaf has developed some unrivaled optimizations. The extraordinary shape and the density of the papillae are the basis for the extremely reduced contact area between surface and water drops. The exceptional dense layer of very small epicuticular wax tubules is a result of their unique chemical composition. The mechanical robustness of the papillae and the wax tubules reduce damage and are the basis for the perfection and durability of the water repellency. A reason for the optimization, particularly of the upper side of the lotus leaf, can be deduced from the fact that the stomata are located in the upper epidermis. Here, the impact of rain and contamination is higher than on the lower epidermis. The lotus plant has successfully developed an excellent protection for this delicate epistomatic surface of its leaves.

  10. Droplet evaporation dynamics on a superhydrophobic surface with negligible hysteresis.

    Science.gov (United States)

    Dash, Susmita; Garimella, Suresh V

    2013-08-27

    We report on experiments of droplet evaporation on a structured superhydrophobic surface that displays very high contact angle (CA ∼ 160 deg), and negligible contact angle hysteresis (contact-angle mode, with contact radius shrinking for almost the entire duration of evaporation. Experiments conducted on Teflon-coated smooth surface (CA ∼ 120 deg) as a baseline also support an evaporation process that is dominated by a constant-contact-angle mode. The experimental results are compared with an isothermal diffusion model for droplet evaporation from the literature. Good agreement is observed for the Teflon-coated smooth surface between the analytical expression and experimental results in terms of the total time for evaporation, transient volume, contact angle, and contact radius. However, for the structured superhydrophobic surface, the experiments indicate that the time taken for complete evaporation of the droplet is greater than the predicted time, across all droplet volumes. This disparity is attributed primarily to the evaporative cooling at the droplet interface due to the high aspect ratio of the droplet and also the lower effective thermal conductivity of the substrate due to the presence of air gaps. This hypothesis is verified by numerically evaluating the temperature distribution along the droplet interface. We propose a generalized relation for predicting the instantaneous volume of droplets with initial CA > 90 deg, irrespective of the mode of evaporation.

  11. Controlling liquid splash on superhydrophobic surfaces by a vesicle surfactant

    Science.gov (United States)

    Song, Meirong; Ju, Jie; Luo, Siqi; Han, Yuchun; Dong, Zhichao; Wang, Yilin; Gu, Zhen; Zhang, Lingjuan; Hao, Ruiran; Jiang, Lei

    2017-01-01

    Deposition of liquid droplets on solid surfaces is of great importance to many fundamental scientific principles and technological applications, such as spraying, coating, and printing. For example, during the process of pesticide spraying, more than 50% of agrochemicals are lost because of the undesired bouncing and splashing behaviors on hydrophobic or superhydrophobic leaves. We show that this kind of splashing on superhydrophobic surfaces can be greatly inhibited by adding a small amount of a vesicular surfactant, Aerosol OT. Rather than reducing splashing by increasing the viscosity via polymer additives, the vesicular surfactant confines the motion of liquid with the help of wettability transition and thus inhibits the splash. Significantly, the vesicular surfactant exhibits a distinguished ability to alter the surface wettability during the first inertial spreading stage of ~2 ms because of its dense aggregates at the air/water interface. A comprehensive model proposed by this idea could help in understanding the complex interfacial interactions at the solid/liquid/air interface. PMID:28275735

  12. Bioinspired Superhydrophobic Highly Transmissive Films for Optical Applications.

    Science.gov (United States)

    Vüllers, Felix; Gomard, Guillaume; Preinfalk, Jan B; Klampaftis, Efthymios; Worgull, Matthias; Richards, Bryce; Hölscher, Hendrik; Kavalenka, Maryna N

    2016-11-01

    Inspired by the transparent hair layer on water plants Salvinia and Pistia, superhydrophobic flexible thin films, applicable as transparent coatings for optoelectronic devices, are introduced. Thin polymeric nanofur films are fabricated using a highly scalable hot pulling technique, in which heated sandblasted steel plates are used to create a dense layer of nano- and microhairs surrounding microcavities on a polymer surface. The superhydrophobic nanofur surface exhibits water contact angles of 166 ± 6°, sliding angles below 6°, and is self-cleaning against various contaminants. Additionally, subjecting thin nanofur to argon plasma reverses its surface wettability to hydrophilic and underwater superoleophobic. Thin nanofur films are transparent and demonstrate reflection values of less than 4% for wavelengths ranging from 300 to 800 nm when attached to a polymer substrate. Moreover, used as translucent self-standing film, the nanofur exhibits transmission values above 85% and high forward scattering. The potential of thin nanofur films for extracting substrate modes from organic light emitting diodes is tested and a relative increase of the luminous efficacy of above 10% is observed. Finally, thin nanofur is optically coupled to a multicrystalline silicon solar cell, resulting in a relative gain of 5.8% in photogenerated current compared to a bare photovoltaic device.

  13. Superhydrophobicity in perfection: the outstanding properties of the lotus leaf.

    Science.gov (United States)

    Ensikat, Hans J; Ditsche-Kuru, Petra; Neinhuis, Christoph; Barthlott, Wilhelm

    2011-01-01

    Lotus leaves have become an icon for superhydrophobicity and self-cleaning surfaces, and have led to the concept of the 'Lotus effect'. Although many other plants have superhydrophobic surfaces with almost similar contact angles, the lotus shows better stability and perfection of its water repellency. Here, we compare the relevant properties such as the micro- and nano-structure, the chemical composition of the waxes and the mechanical properties of lotus with its competitors. It soon becomes obvious that the upper epidermis of the lotus leaf has developed some unrivaled optimizations. The extraordinary shape and the density of the papillae are the basis for the extremely reduced contact area between surface and water drops. The exceptional dense layer of very small epicuticular wax tubules is a result of their unique chemical composition. The mechanical robustness of the papillae and the wax tubules reduce damage and are the basis for the perfection and durability of the water repellency. A reason for the optimization, particularly of the upper side of the lotus leaf, can be deduced from the fact that the stomata are located in the upper epidermis. Here, the impact of rain and contamination is higher than on the lower epidermis. The lotus plant has successfully developed an excellent protection for this delicate epistomatic surface of its leaves.

  14. Probing droplets on superhydrophobic surfaces by synchrotron radiation scattering techniques

    Energy Technology Data Exchange (ETDEWEB)

    Accardo, Angelo [Istituto Italiano di Tecnologia, Via Morego 30, Genova 16163 (Italy); Di Fabrizio, Enzo [KAUST (King Abdullah University of Science and Technology), Jeddah (Saudi Arabia); BIONEM Lab at University Magna Graecia, Campus Salvatore Venuta, Viale Europa 88100, Germaneto-Catanzaro (Italy); Limongi, Tania [KAUST (King Abdullah University of Science and Technology), Jeddah (Saudi Arabia); Marinaro, Giovanni [Istituto Italiano di Tecnologia, Via Morego 30, Genova 16163 (Italy); European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex (France); Riekel, Christian, E-mail: riekel@esrf.fr [European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex (France)

    2014-06-10

    A comprehensive review about the use of micro- and nanostructured superhydrophobic surfaces as a tool for in situ X-ray scattering investigations of soft matter and biological materials. Droplets on artificially structured superhydrophobic surfaces represent quasi contact-free sample environments which can be probed by X-ray microbeams and nanobeams in the absence of obstructing walls. This review will discuss basic surface wettability concepts and introduce the technology of structuring surfaces. Quasi contact-free droplets are compared with contact-free droplets; processes related to deposition and evaporation on solid surfaces are discussed. Droplet coalescence based on the electrowetting effect allows the probing of short-time mixing and reaction processes. The review will show for several materials of biological interest that structural processes related to conformational changes, nucleation and assembly during droplet evaporation can be spatially and temporally resolved by raster-scan diffraction techniques. Orientational ordering of anisotropic materials deposited during solidification at pinning sites facilitates the interpretation of structural data.

  15. Superhydrophobic chitosan-based coatings for textile processing

    Energy Technology Data Exchange (ETDEWEB)

    Ivanova, N.A., E-mail: NAI-72@yandex.ru [Ivanovo State Textile Academy, F. Engels Avenue 21, 153000 Ivanovo (Russian Federation); Philipchenko, A.B. [Kazan State Medical University, Butlerova 49, 420012 Kazan, Tatarstan (Russian Federation)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Chitosan nanoparticles can be used for design of the superhydrophobic anti-bacterial textile. Black-Right-Pointing-Pointer Spraying the nanoparticle dispersion allows one to get multiscale textured coating. Black-Right-Pointing-Pointer Relative number of fluoroanions per elementary unit of chitosan plays the crucial role in the structure of aggregates and coating wettability. - Abstract: A simple method to design the superhydrophobic anti-bacterial textile for biomedical applications was developed. For the coating formulation the spraying of nanoparticles dispersion over the textile sample was applied, allowing the way to get multiscale textured layer on a top of cotton fabric. The anti-bacterial functionality of coating is supported by using chitosan-based nanoparticles. In our approach the fabrication of nanoparticles was based on electrostatic interaction between amine group of chitosan and negatively charged fluoroanion. It was demonstrated that the relative number of fluoroanions per elementary unit of chitosan plays the crucial role in the structure of aggregates in the coating and its wettability as well as in durability of coatings in contact with aqueous media.

  16. Effect of superhydrophobic surface morphology on evaporative deposition patterns

    Science.gov (United States)

    Dicuangco, Mercy; Dash, Susmita; Weibel, Justin A.; Garimella, Suresh V.

    2014-05-01

    Prediction and active control of the spatial distribution of particulate deposits obtained from sessile droplet evaporation are vital in printing, nanostructure assembly, biotechnology, and other applications that require localized deposits. This Letter presents surface wettability-based localization of evaporation-driven particulate deposition and the effect of superhydrophobic surface morphology on the distribution of deposits. Sessile water droplets containing suspended latex particles are evaporated on non-wetting textured surfaces with varying microstructure geometry at ambient conditions. The droplets are visualized throughout the evaporation process to track the temporal evolution of contact radius and apparent contact angle. The resulting particle deposits on the substrates are quantitatively characterized. The experimental results show that superhydrophobic surfaces suppress contact-line deposition during droplet evaporation, thereby providing an effective means of localizing the deposition of suspended particles. A correlation between deposit size and surface morphology, explained in terms of the interface pressure balance at the transition between wetting states, reveals an optimum surface morphology for minimizing the deposit coverage area.

  17. Dynamic effects induced transition of droplets on biomimetic superhydrophobic surfaces.

    Science.gov (United States)

    Jung, Yong Chae; Bhushan, Bharat

    2009-08-18

    Superhydrophobic surfaces have considerable technological potential for various applications because of their extreme water-repellent properties. Dynamic effects, such as the bouncing and vibration of a droplet, can destroy the composite solid-air-liquid interface. The impact pressure of a bouncing droplet and the inertia force of a vibrating droplet affect the transition from a solid-air-liquid interface to a solid-liquid interface. Therefore, it is necessary to study the dynamic effect of droplets under various system parameters (impact velocity and frequency and amplitude of vibration). A new model for the prediction of the wetting and dewetting process during droplet vibration based on the relationship between the adhesion force and the inertia force of a droplet is proposed. To investigate whether micro-, nano-, and hierarchical structures can resist the destabilizing factors responsible for the transition, a study of bouncing and vibration of a water droplet is systematically conducted on various surfaces. The physics of wetting phenomena for water droplet studies is of fundamental importance in the geometrical design of superhydrophobic surfaces.

  18. Superhydrophobic perfluoropolymer/polystyrene blend films induced by nonsolvent

    Science.gov (United States)

    Gengec, Nevin Atalay; Cengiz, Ugur; Erbil, H. Yildirim

    2016-10-01

    Statistical copolymers of perfluoroalkyl ethyl acrylate (Zonyl-TAN) and methyl methacrylate (MMA) were synthesized in a CO2 polymerization system where a CO2-expanded monomer mixture was formed at 13 MPa, and 80 °C by using AIBN as initiator. Flat and superhydrophobic surfaces were subsequently prepared on glass slides by applying a phase separation process where the synthesized p(TAN-co-MMA) copolymer and polystyrene (PS) were dissolved in THF solvent. Ethanol was added as the non-solvent to introduce superhydrophobicity during film formation. Water contact angle on the flat p(TAN-co-MMA) copolymer was 118° and increased up to 170° with the formation of surface roughness. The ratio of the ethanol non-solvent in the blend solution has an important effect on the magnitude of surface roughness during the phase separation process. Both pits and protrusions of 1-10 μm in size were formed on the surface when non-solvent was used. Surface roughness increased with the increase in the ethanol ratio and the PS content of the blend solution.

  19. Superhydrophobic epoxy coating modified by fluorographene used for anti-corrosion and self-cleaning

    Science.gov (United States)

    Yang, Zhengqing; Wang, Lida; Sun, Wen; Li, Sijia; Zhu, Tianzhen; Liu, Wei; Liu, Guichang

    2017-04-01

    A facile method for the fabrication of organic coating with superhydrophobic surface on copper substrate is presented in this paper. Liquid-phase exfoliated fluorographene (FG) nanosheets, a low-surface-energy material with different sizes and shapes, are spatially stuck on the surface of epoxy resin coating to build rough surface with random micro/nano structure. The built coating system displays superior protection performances due to its self-cleaning function, mechanical abrasion resistance and chemical stability both in acidic and alkaline aqueous solutions. It not only provides a facile process for superhydrophobic modification of organic coating, but also introduces a new and effective strategy to protect materials by synergistically coupling the protection function of both superhydrophobic surface and organic coating, which can be used for large-scale manufacturing of superhydrophobic organic coating in industrial applications.

  20. Preparation of superhydrophobic silver nano coatings with feather-like structures by electroless galvanic deposition

    Institute of Scientific and Technical Information of China (English)

    FENG XiaoJuan; SHI YanLong; WANG YongSheng; YUE GuoRen; YANG Wu

    2013-01-01

    Superhydrophobic silver nanocoatings with feather-like morphology are fabricated on copper substrates by electroless galvanic deposition.The coating exhibit superhydrophobicity with a contact angle of 156.4° and glide angle of 4° without any further surface modification.Scanning electron microscope (SEM),X-ray diffraction (XRD) and contact angle measurements are used to investigate the morphology,crystal structure and superhydrophobicity,respectively,of the coatings.The coatings exhibit high thermal stability; their water contact angle did not change when the coatings were heated to 200℃ for 2 h.The mechanism of superhydrophobicity of the silver coating is discussed based on the work of Amirfazli,Wenzel and Cassie.