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Sample records for nanometric water menisci

  1. Universal Long-Range Nanometric Bending of Water by Light

    Science.gov (United States)

    Verma, Gopal; Singh, Kamal P.

    2015-10-01

    Resolving mechanical effects of light on fluids has fundamental importance with wide applications. Most experiments to date on optofluidic interface deformation exploited radiation forces exerted by normally incident lasers. However, the intriguing effects of photon momentum for any configuration, including the unique total internal reflection regime, where an evanescent wave leaks above the interface, remain largely unexplored. A major difficulty in resolving nanomechanical effects has been the lack of a sensitive detection technique. Here, we devise a simple setup whereby a probe laser produces high-contrast Newton-ring-like fringes from a sessile water drop. The mechanical action of the photon momentum of a pump beam modulates the fringes, thus allowing us to perform a direct noninvasive measurement of a nanometric bulge with sub-5-nm precision. Remarkably, a <10 nm difference in the height of the bulge due to different laser polarizations and nonlinear enhancement in the bulge near total internal reflection is isolated. In addition, the nanometric bulge is shown to extend far longer, 100 times beyond the pump spot. Our high precision data validate the century-old Minkowski theory for a general angle and offer potential for novel optofluidic devices and noncontact nanomanipulation strategies.

  2. Observation of Nanometric Silicon Oxide Bifilms in a Water-Atomized Hypereutectic Cast Iron Powder

    Science.gov (United States)

    Boisvert, Mathieu; Christopherson, Denis; L'Espérance, Gilles

    2016-10-01

    This study investigated the reasons for the irregular structure of primary graphite nodules that were formed in a hypereutectic cast iron powder during water atomization. The graphite nodules contain a significant amount of micron-sized pores and multiple nanometric voids that formed from silicon oxide bifilms. The bifilms theory is often used to explain the mechanisms responsible for the presence of pores in castings. However, even if many results presented in the literature tend to corroborate the existence of bifilms, to this date, only indirect evidences of their existence were presented. The observations presented in this paper are the first to show the double-sided nature of these defects. These observations support the bifilms theory and give an explanation for the presence of porosities in castings. The bifilms were used as substrate for graphite growth during solidification. The irregular structure of the graphite nodules is a consequence of the rather random structure of the bifilms that were introduced in the melt as a result of turbulences on the surface of the melt during pouring. The confirmation of the existence of bifilms can contribute to the understanding of the mechanical properties of various metallic parts.

  3. Geometric Evaluation of Fresh Menisci and Menisci Preserved in 98% Glycerin: Study in Rabbits (Oryctolagus cuniculus

    Directory of Open Access Journals (Sweden)

    Diana Marcela Perez Berrio

    2014-07-01

    Full Text Available Meniscus alloimplants have been used as a source of tissue for replacement in case of breakage or irreparable damage. To determine possible changes by conservation, the study proposed to geometrically evaluate fresh menisci and menisci preserved in 98% glycerin. 15 medial menisci from eight albino rabbits of New Zealand breed were used, divided into three groups: five fresh menisci (GI; five menisci preserved in 98% glycerin for eight months (GII, and five menisci preserved in 98% glycerin for eight months and then rehydrated in 0.9% saline solution for 24 hours (GIII. All menisci were measured with vernier caliper at seven points of their geometric structure. The study established that there were no statistical differences in the measurements of GII and GIII when compared to GI; there was no difference either in the measurements of GIII when compared to GII, thus rehydration in antibiotic saline solution for 24 hours can be considered unnecessary.

  4. MRI of menisci repaired with bioabsorbable arrows

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    Mustonen, Antti O.T.; Kiuru, Martti; Koskinen, Seppo K. [Helsinki University Hospital - Radiology, Helsinki (Finland); Tielinen, Laura; Lindahl, Jan; Hirvensalo, Eero [Helsinki University Hospital - Traumatology, Helsinki (Finland)

    2006-07-15

    To analyze with conventional magnetic resonance imaging (MRI) the signal appearance of menisci repaired with bioabsorbable arrows. Forty-four patients with 47 meniscal tears treated with bioabsorbable arrows underwent follow-up conventional MRI examination. The time interval between the surgery and MRI varied from 5 to 67 months (mean 26 months). Twenty-six patients also had concurrent repair of torn anterior cruciate ligament. The following grades were used to classify meniscal signal intensity: (a) G0; low signal intensity on all sequences and regular configuration in every plane, (b) G1; increased signal intensity within the meniscus, not extending to the meniscal surface, (c) G2; increased signal intensity linear in shape, which may or may not communicate with the capsular margin of the meniscus, without extending to the meniscal surface, and (d) G3; increased signal intensity extending to the meniscal surface. Thirteen menisci (27.5%) had normal signal intensity, 13 menisci (27.5%) Grade 1 signal intensity, 9 menisci (19%) Grade 2 signal intensity and 12 menisci (26%) Grade 3 signal intensity. The time difference between operation and MRI was statistically significant between the G0 (36 months) and G3 groups (14 months; P=0.0288). There was no statistical significance in different grades between medial and lateral meniscus or between patients with operated or intact ACL. On physical examination sixteen patients reported slight symptoms, seen evenly in each group. (orig.)

  5. An enhanced photocatalytic response of nanometric TiO2 wrapping of Au nanoparticles for eco-friendly water applications

    Science.gov (United States)

    Scuderi, Viviana; Impellizzeri, Giuliana; Romano, Lucia; Scuderi, Mario; Brundo, Maria V.; Bergum, Kristin; Zimbone, Massimo; Sanz, Ruy; Buccheri, Maria A.; Simone, Francesca; Nicotra, Giuseppe; Svensson, Bengt G.; Grimaldi, Maria G.; Privitera, Vittorio

    2014-09-01

    We propose a ground-breaking approach by an upside-down vision of the Au/TiO2 nano-system in order to obtain an enhanced photocatalytic response. The system was synthesized by wrapping Au nanoparticles (~8 nm mean diameter) with a thin layer of TiO2 (~4 nm thick). The novel idea of embedding Au nanoparticles with titanium dioxide takes advantage of the presence of metal nanoparticles, in terms of electron trapping, without losing any of the TiO2 exposed surface, so as to favor the photocatalytic performance of titanium dioxide. A complete structural characterization was made by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The remarkable photocatalytic performance together with the stability of the nano-system was demonstrated by degradation of the methylene blue dye in water. The non-toxicity of the nano-system was established by testing the effect of the material on the reproductive cycle of Mytilus galloprovincialis in an aquatic environment. The originally synthesized material was also compared to conventional TiO2 with Au nanoparticles on top. The latter system showed a dispersion of Au nanoparticles in the liquid environment, due to their instability in the aqueous solution that clearly represents an environmental contamination issue. Thus, the results show that nanometric TiO2 wrapping of Au nanoparticles has great potential in eco-friendly water/wastewater purification.

  6. Lower Saccharide Nanometric Materials and Methods

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    Schilling, Christopher H.; Tomasik, Piotr; Sikora, Marek

    2004-07-13

    A ceramic composition having at least one nanometric ceramic powder, at least one lower saccharide, and water. The composition is useful in many industrial applications, including preparation of stronger and substantially defect free green and sintered ceramic bodies.

  7. Interfaces: nanometric dielectrics

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    Lewis, T J [School of Informatics, University of Wales Bangor, Dean Street, Bangor, Gwynedd, LL70 9PX (United Kingdom)

    2005-01-21

    The incorporation of nanometric size particles in a matrix to form dielectric composites shows promise of materials (nanodielectrics) with new and improved properties. It is argued that the properties of the interfaces between the particles and the matrix, which will themselves be of nanometric dimensions, will have an increasingly dominant role in determining dielectric performance as the particle size decreases. The forces that determine the electrical and dielectric properties of interfaces are considered, with emphasis on the way in which they might influence composite behaviour. A number of examples are given in which interfaces at the nanometric level exercise both passive and active control over dielectric, optical and conductive properties. Electromechanical properties are also considered, and it is shown that interfaces have important electrostrictive and piezoelectric characteristics. It is demonstrated that the process of poling, namely subjecting macroscopic composite materials to electrical stress and raised temperatures to create piezoelectric materials, can be explained in terms of optimizing the collective response of the nanometric interfaces involved. If the electrical and electromechanical features are coupled to the long-established electrochemical properties, interfaces represent highly versatile active elements with considerable potential in nanotechnology.

  8. Interfaces: nanometric dielectrics

    Science.gov (United States)

    Lewis, T. J.

    2005-01-01

    The incorporation of nanometric size particles in a matrix to form dielectric composites shows promise of materials (nanodielectrics) with new and improved properties. It is argued that the properties of the interfaces between the particles and the matrix, which will themselves be of nanometric dimensions, will have an increasingly dominant role in determining dielectric performance as the particle size decreases. The forces that determine the electrical and dielectric properties of interfaces are considered, with emphasis on the way in which they might influence composite behaviour. A number of examples are given in which interfaces at the nanometric level exercise both passive and active control over dielectric, optical and conductive properties. Electromechanical properties are also considered, and it is shown that interfaces have important electrostrictive and piezoelectric characteristics. It is demonstrated that the process of poling, namely subjecting macroscopic composite materials to electrical stress and raised temperatures to create piezoelectric materials, can be explained in terms of optimizing the collective response of the nanometric interfaces involved. If the electrical and electromechanical features are coupled to the long-established electrochemical properties, interfaces represent highly versatile active elements with considerable potential in nanotechnology.

  9. Histological characteristics of knee menisci in patients with osteoarthritis.

    Science.gov (United States)

    McDaniel, Dalton; Tilton, Emily; Dominick, Kathryn; Flory, Kale; Ernest, Taylor; Johnson, Jane C; Main, Donet C; Kondrashov, Peter

    2017-09-01

    Existing data indicate knee menisci in patients with osteoarthritis (OA) show tearing, maceration, and fragmentation, but little is known about the change in histological structure. The aim of this study was to evaluate the change in the menisci histological structure in patients with clinically diagnosed knee OA. Fourteen patients undergoing surgical treatment of knee OA (OA group) and 14 cadaveric knees (control group) were assessed. Demographic data, medical history, synovial fluid, OA severity, medial meniscus (MM) tissue, and lateral meniscus (LM) tissue were collected from the OA group. Three nonconsecutive 10 μm cross-sectional tissue slices of menisci were analyzed for percentage of tissue calcification. Exact Mann-Whitney tests and Spearman correlation coefficients tested for relationships between variables. The major change in the histological structure of the menisci in patients with OA was calcification of the matrix, which was significantly greater in the OA group compared with the control group for MM (OA: 11.9%, cadaver: 5.17%; P < 0.001) and LM tissues (OA: 11.1%, cadaver: 4.2%; P < 0.001). A correlation between percent calcification of the MM and LM tissues existed in the OA group (ρ = 0.56, P = 0.04) but not the control group (P = 0.20). The most pronounced pathological change in the histology of menisci was calcification of the cartilage matrix, significantly greater in the OA group than the control group. A strong correlation between percent calcification of MM and LM tissues in patients with OA indicates changes in fibrocartilage matrix of menisci progress similarly in the medial and lateral compartments of the knee. Clin. Anat. 30:805-810, 2017. © 2017Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  10. Rheological Properties of Aqueous Nanometric Alumina Suspensions

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    Li, Chuanping [Iowa State Univ., Ames, IA (United States)

    2004-01-01

    Colloidal processing is an effective and reliable approach in the fabrication of the advanced ceramic products. Successful colloidal processing of fine ceramic powders requires accurate control of the rheological properties. The accurate control relies on the understanding the influences of various colloidal parameters on the rheological properties. Almost all research done on the rheology paid less attention to the interactions of particle and solvent. However, the interactions of the particles are usually built up through the media in which the particles are suspended. Therefore, interactions of the particle with the media, the adsorbed layers on the particle surface, and chemical and physical properties of media themselves must influence the rheology of the suspension, especially for the dense suspensions containing nanosized particles. Relatively little research work has been reported in this area. This thesis addresses the rheological properties of nanometric alumina aqueous suspensions, and paying more attention to the interactions between particle and solvent, which in turn influence the particle-particle interactions. Dense nanometric alumina aqueous suspensions with low viscosity were achieved by environmentally-benign fructose additives. The rheology of nanometric alumina aqueous suspensions and its variation with the particle volume fraction and concentration of fructose were explored by rheometry. The adsorptions of solute (fructose) and solvent (water) on the nanometric alumina particle surfaces were measured and analyzed by TG/DSC, TOC, and NMR techniques. The mobility of water molecules in the suspensions and its variation with particle volume fractions and fructose additive were determined by the 17O NMR relaxation method. The interactions between the nanometric alumina particles in water and fructose solutions were investigated by AFM. The results indicated that a large number of water layers were physically bound on the particles

  11. Rheological Properties of Aqueous Nanometric Alumina Suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Chuanping Li

    2004-12-19

    Colloidal processing is an effective and reliable approach in the fabrication of the advanced ceramic products. Successful colloidal processing of fine ceramic powders requires accurate control of the rheological properties. The accurate control relies on the understanding the influences of various colloidal parameters on the rheological properties. Almost all research done on the rheology paid less attention to the interactions of particle and solvent. However, the interactions of the particles are usually built up through the media in which the particles are suspended. Therefore, interactions of the particle with the media, the adsorbed layers on the particle surface, and chemical and physical properties of media themselves must influence the rheology of the suspension, especially for the dense suspensions containing nanosized particles. Relatively little research work has been reported in this area. This thesis addresses the rheological properties of nanometric alumina aqueous suspensions, and paying more attention to the interactions between particle and solvent, which in turn influence the particle-particle interactions. Dense nanometric alumina aqueous suspensions with low viscosity were achieved by environmentally-benign fructose additives. The rheology of nanometric alumina aqueous suspensions and its variation with the particle volume fraction and concentration of fructose were explored by rheometry. The adsorptions of solute (fructose) and solvent (water) on the nanometric alumina particle surfaces were measured and analyzed by TG/DSC, TOC, and NMR techniques. The mobility of water molecules in the suspensions and its variation with particle volume fractions and fructose additive were determined by the {sup 17}O NMR relaxation method. The interactions between the nanometric alumina particles in water and fructose solutions were investigated by AFM. The results indicated that a large number of water layers were physically bound on the particles

  12. Ultrasonic actuators for nanometre positioning

    Science.gov (United States)

    Snitka

    2000-03-01

    This paper deals with ultrasonic motors based on bimodal plate vibrations and their application to nanometre resolution stepper positioning systems. The concept of a linear ultrasonic motor drive capable of nanometric steps, long-range travel and reversible controlled motion is presented. The motor concept developed is based on the superposition of a longitudinal and bending vibrations of a rectangular resonator. The ultrasonic motor model based on system identification via discrete observations and prediction has been developed for control applications. The control algorithm for ultrasonic motors has been developed and theoretical investigations have been made. The open loop positioning system with designed stepper ultrasonic drive produced 10 nm resolution and 5% displacement repeatability. The system with computer controlled position feedback has shown 0.3 micron positioning accuracy over the 100 mm positioning range.

  13. Acute injury affects lubricin expression in knee menisci: an immunohistochemical study.

    Science.gov (United States)

    Musumeci, Giuseppe; Loreto, Carla; Carnazza, Maria Luisa; Cardile, Venera; Leonardi, Rosalia

    2013-03-01

    The aim of this study was to investigate for the first time lubricin expression in intact menisci and in menisci from patients with recent knee joint injury using histology, immunohistochemistry, Western blotting and gene expression analysis, to provide insights into pathological processes affecting meniscal tissue. Lubricin expression was studied in vivo in 20 patients (14 males and 6 females) with recent joint injury subjected to arthroscopic partial meniscectomy and in vitro in fibroblast-like cells from meniscus tissue to establish whether it is down-regulated following acute traumatic knee injury. The control group consisted of cadaver donors with normal menisci. Histology demonstrated a normal tissue without structural changes in control samples and structural alterations and clefts in injured menisci. Very strong lubricin immunohistochemical staining was observed in intact menisci; in contrast weak staining was seen in injured menisci. Western blot and mRNA expression analysis also demonstrated strong lubricin expression in control cells and a negligible amount of lubricin in injured fibroblast-like cells. Our data provide information concerning the immediate in vivo response to injury of human knee menisci by documenting early changes in the boundary-lubricating ability of synovial fluid and articular cartilage integrity. These findings may provide the biological basis for developing novel medical therapies to be applied before surgical treatment to preserve tissue function and prevent cartilage damage.

  14. Collagenous fibril texture of the human knee joint menisci.

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    Petersen, W; Tillmann, B

    1998-04-01

    Anatomical and clinical literature describes the arrangement of collagen fibrils in the human meniscus as being "arcade-like". The "arcade-like" orientation, mainly running in a radial direction in the internal circumference and in a circular direction in the external circumference, was found in polarization light microscopic studies. This, however, does not provide a mechanical explanation for the direction of meniscus tears. In view of this contradiction collagen fibrils in the menisci of adults aged from 18 to 85 years were exposed layer-by-layer to study their arrangement by scanning electron microscopy. The results obtained by this procedure were compared to the path of the split lines. Scanning electron microscopy reveals three distinct layers in the meniscus cross section: (1) The tibial and femoral sides of the meniscus surfaces are covered by a meshwork of thin fibrils with a diameter of approximately 30 nm. (2) Beneath the superficial network there is a layer of lamellalike collagen fibril bundles on the tibial and femoral surface. In the area of the external circumference of the anterior and posterior segments the bundles of collagen fibrils are arranged in a radial direction. In all other parts the collagen fibril bundles intersect at various angles. (3) The main portion of the meniscus collagen fibrils are located in the central region between the femoral and the tibial surface layers. Everywhere in the central main portion of the meniscus the bundles of collagen fibrils are orientated in a circular manner. The split lines in the region of the internal circumference of the menisci are arranged in a circular manner, generally running in a radial direction in the portions adjacent to the base. Scanning electron microscopy reveals that the direction of the split lines depends on the orientation of the collagen fibrils in the superficial lamellar layer. The arcade-like path of the collagen fibrils described in the literature can not be confirmed either by

  15. Expression of collagen type I in unaltered and osteoarthritic menisci of knee joint

    Directory of Open Access Journals (Sweden)

    Sladojević Igor

    2016-01-01

    Full Text Available Introduction. Knee osteoarthritis is a progressive degenerative disease which affects meniscal tissue. The aim of this study was to determine the differences in collagen type I expression in macroscopically unaltered and osteoarthritic menisci, and correlate the expression with the grade of macroscopic damage, age and body mass index of patients, preoperative condition of anterior cruciate ligament, angulation and knee contracture. Material and Methods. The control group consisted of 10 macroscopically unaltered menisci, while the experimental group had 35 osteoarthritic menisci. Besides macroscopic grading of meniscal damage, the analysis of collagen type I expression was determined by immunohistochemical staining with the corresponding antibody using semiquantitative scale scores and quantitative parameters: intensity of expression and stained area size. Results. The results of semiquantitative evaluation showed a statistically significant decrease in collagen type I expression in osteoarthritic menisci, which correlated with an increase in macroscopic damage grade. The results of quantitative evaluation did not show a statistically significant decrease in the expression. In posterior meniscal horns, a more intense collagen type I expression was seen in the women, as well as a positive correlation of quantitatively evaluated expression with body mass index. Collagen type I expression in the anterior horns was significantly lower in varus alignment. Conclusion. In the semiquantitative evaluation, collagen type I expression in osteoarthritic menisci was significantly lower compared to macroscopically unchanged menisci. The decrease in the expression level correlates with the increase in the grade of macroscopic meniscal damage. There was no statistically significant difference in the quantitative evaluation of expression.

  16. Evaluation of pre-stresses in the menisci of human knee joint using microindentation.

    Science.gov (United States)

    Kwak, Dai Soon; Bae, Ji Yong; Kim, Sung Youb; Jeon, Insu; Lu, Tian Jian

    2014-01-01

    To evaluate the pre-stress in the menisci of a human knee joint, the technique of microindentation was adopted. Five specimens each for lateral and medial menisci attached to the tibia were prepared from the knee joints of Korean cadavers to represent the pre-stress state of the meniscus. To create test specimens for the stress-free state of the meniscus, each meniscus was resected from the tibia and cut into three parts, which were subsequently attached to a metal plate. Indentations were carried out in each meniscus in both the pre-stress state and the stress-free state. The pre-stresses in the menisci were evaluated using the load-versus-depth curves. Compressive pre-stresses were found in the menisci. For each indentation region, the pre-stresses in the medial meniscus were higher than in the lateral meniscus. The highest pre-stress in both the lateral and medial meniscus was found in the posterior regions, while the anterior regions experienced the lowest pre-stress. The obtained pre-stresses can be used for the accurate numerical analysis, the fabrication of artificial menisci, and the diagnosis of meniscal disease progression for human knee joints.

  17. Mapping surface tension induced menisci with application to tensiometry and refractometry.

    Science.gov (United States)

    Mishra, Avanish; Kulkarni, Varun; Khor, Jian-Wei; Wereley, Steve

    2015-07-28

    In this work, we discuss an optical method for measuring surface tension induced menisci. The principle of measurement is based upon the change in the background pattern produced by the curvature of the meniscus acting as a lens. We measure the meniscus profile over an inclined glass plate and utilize the measured meniscus for estimation of surface tension and refractive index.

  18. Propriedades mecânicas de meniscos frescos de coelhos e preservados em glicerina 98% Mechanical properties of the fresh rabbit menisci and of the menisci preserved in glycerin 98%

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    Liana Mesquita Vilela

    2010-05-01

    Full Text Available O presente estudo avaliou a resistência à compressão de meniscos mediais de coelhos da raça Nova Zelândia, por meio de teste mecânico de compressão. Trinta meniscos foram distribuídos em três grupos: grupo MF, composto por dez meniscos frescos; grupo MG, dez meniscos preservados em glicerina 98%, por 30 dias, e grupo MR, dez meniscos preservados em glicerina 98%, por 30 dias e reidratados em NaCl 0,9%, por 12 horas. Os meniscos de cada grupo foram submetidos ao teste de compressão no sentido perpendicular ao seu plano anatômico regular e foram avaliados o limite de elasticidade, a deformação elástica, a tensão ao ponto de ruptura e ao limite de elasticidade e ainda, o índice de rigidez. Os meniscos dos grupos preservados, MG e MR, tiveram o limite elástico semelhante ao grupo de meniscos frescos (MF. O grupo de meniscos em glicerina (MG apresentou menor capacidade de deformação elástica (PThe present study evaluated the compressive strength of medial menisci of New Zealand rabbits, through mechanical compression test. Thirty menisci were distributed in three groups: group MF, composed by ten fresh menisci; MG group, composed by ten menisci preserved in 98% glycerin for 30 days; and, group MR, ten menisci preserved in 98% glycerin for 30 days and rehydrated in NaCl 0.9% for 12 hours. The menisci in each group were submitted to compression test in the perpendicular direction to the anatomical plane and had the elasticity limit, the elastic deformity, the rupture stress point and the stiffness index evaluated. The menisci from the preserved groups MG and MR had the elastic limit similar to the fresh menisci group (MF. The group of menisci preserved in glycerin (MG presented lower elastic deformity capacity (P<0.05 if compared to the other groups, MF and MR, and a higher tension capacity at elastic limit. The menisci from group (MG presented higher stiffness (P<0.05 than the ones in the MF and MR groups. It can be concluded that

  19. The structural and compositional transition of the meniscal roots into the fibrocartilage of the menisci.

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    Andrews, Stephen H J; Rattner, Jerome B; Jamniczky, Heather A; Shrive, Nigel G; Adesida, Adetola B

    2015-02-01

    The meniscal roots, or insertional ligaments, firmly attach the menisci to tibial plateau. These strong attachments anchor the menisci and allow for the generation of hoop stress in the tissue. The meniscal roots have a ligament-like structure that transitions into the fibrocartilagenous structure of the meniscal body. The purpose of this study was to carry out a complete analysis of the structure and tissue organization from the body of the meniscus through the transition region and into the insertional roots. Serial sections were obtained from the meniscal roots into the meniscal body in fixed juvenile bovine menisci. Sections were stained for collagen and proteoglycans (PG) using fast green and safranin-o staining protocols. Unstained sections were imaged used a backlit stereo microscope. Optical projection tomography (OPT) was employed to evaluate the three-dimensional collagen architecture of the root-meniscus transition in lapine menisci. Tie-fibres were observed in the sections of the ligaments furthest from the bovine meniscal body. Blood vessels were observed to be surrounded by these tie-fibres and a PG-rich region within the ligaments. Near the tibial insertion, the roots contained large ligament-like collagen fascicles. In sections approaching the meniscus, there was an increase in tie-fibre size and density. Small tie-fibres extended into the ligament from the epiligamentous structure in the outermost sections of the meniscal roots, while large tie-fibre bundles were apparent at the meniscus transition. The staining pattern indicates that the root may continue into the outer portion of the meniscus where it then blends with the more fibrocartilage-like inner portions of the tissue. In unstained sections it was observed that the femoral side of the epiligamentous structure surrounding the root becomes more fibrous and thickens in the inferior inner portion of the posterior medial root. This thickening changes the shape of the root to more closely

  20. On the capillary interaction between solid plates forming menisci on the surface of a liquid

    Science.gov (United States)

    Saif, Taher A.

    2002-12-01

    A hydrophilic or a hydrophobic long rigid solid plate of finite width, forming a meniscus with a liquid in a uniform gravitational field is considered. The one-dimensional meniscus with prescribed heights of the triple point from the far-field liquid surface is investigated analytically using the Young Laplace equation. It is found that for a hydrophilic plate, the vertical force necessary to break the meniscus during removal of the plate from the liquid is larger than the force necessary to break the meniscus during submersion of the plate into the liquid. Furthermore, the capillary force on the plate reaches a maximum before the meniscus collapses during removal, but no maximum exists before collapse during submersion. The reverse is true when the plate is hydrophobic. The study is then extended to investigate the interaction force between two plates, each forming a meniscus with the liquid. The elevations of the plates from the far-field liquid surface are prescribed, in contrast to earlier studies where interaction between long cylinders floating under self weight was considered. Here, the menisci are determined exactly using the Young Laplace equation. It is shown that for prescribed plate elevations, there can be at most two possible pairs of menisci between them. Each pair bifurcates from a meniscus that is determined by the elevations of the plates and the gap between them. Furthermore, as known for solids floating under self-weight, the horizontal component of the interaction force is attractive for similar menisci (e.g. when the two plates are equally displaced in or out of the liquid), and repulsive when they form opposite menisci. It is shown that if the two menisci are of the same type, but not similar (e.g. one plate is pushed more into the liquid than the other), then the force is attractive at long distances, and may be repulsive at shorter distances with a stable equilibrium at a finite distance between the plates, depending on the elevations of

  1. Elastic vibrations of spheroidal nanometric particles

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    Hernández-Rosas, Juan; Picquart, Michel; Haro-Poniatowski, Emmanuel; Kanehisa, Makoto; Jouanne, Michel; François Morhange, Jean

    2003-11-01

    Particles of nanometric size show low-frequency vibrational modes that can be observed by Raman spectroscopy. These modes involve the collective motion of large numbers of atoms and it is possible to calculate their frequency using elasticity theory. In this work a simple model for oblate-shaped nanoparticles is developed and compared with experimental results obtained in bismuth nanoparticles. It is found that the agreement between theory and experiment is improved in comparison to the spherical model usually employed. However for the smallest particles the elastic model is no longer valid and lattice discreteness has to be considered.

  2. Elastic vibrations of spheroidal nanometric particles

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Rosas, Juan [Departamento de FIsica, Universidad Autonoma Metropolitana Iztapalapa, Apartado Postal 55-534, Mexico, DF 09340 (Mexico); Picquart, Michel [Departamento de FIsica, Universidad Autonoma Metropolitana Iztapalapa, Apartado Postal 55-534, Mexico, DF 09340 (Mexico); Haro-Poniatowski, Emmanuel [Departamento de FIsica, Universidad Autonoma Metropolitana Iztapalapa, Apartado Postal 55-534, Mexico, DF 09340 (Mexico); Kanehisa, Makoto [Laboratoire de Physique des Milieux Desordonnes et Heterogenes, UMR CNRS 7603, Universite Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Jouanne, Michel [Laboratoire de Physique des Milieux Desordonnes et Heterogenes, UMR CNRS 7603, Universite Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Morhange, Jean Francois [Laboratoire de Physique des Milieux Desordonnes et Heterogenes, UMR CNRS 7603, Universite Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris Cedex 05 (France)

    2003-11-12

    Particles of nanometric size show low-frequency vibrational modes that can be observed by Raman spectroscopy. These modes involve the collective motion of large numbers of atoms and it is possible to calculate their frequency using elasticity theory. In this work a simple model for oblate-shaped nanoparticles is developed and compared with experimental results obtained in bismuth nanoparticles. It is found that the agreement between theory and experiment is improved in comparison to the spherical model usually employed. However for the smallest particles the elastic model is no longer valid and lattice discreteness has to be considered.

  3. T1rho MRI of menisci and cartilage in patients with osteoarthritis at 3T

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ligong, E-mail: ligong.wang@nyumc.org [Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, NY (United States); Chang, Gregory, E-mail: gregory.chang@nyumc.org [Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, NY (United States); Xu, Jian, E-mail: jian.xu.sz@siemens.com [Siemens HealthCare, New York, NY (United States); Vieira, Renata L.R., E-mail: Renata.Vieira@nyumc.org [Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, NY (United States); Krasnokutsky, Svetlana, E-mail: Svetlana.Krasnokutsky@nyumc.org [Division of Rheumatology, New York University Langone Medical Center, New York, NY (United States); Abramson, Steven, E-mail: StevenB.Abramson@nyumc.org [Division of Rheumatology, New York University Langone Medical Center, New York, NY (United States); Regatte, Ravinder R., E-mail: Ravinder.Regatte@nyumc.org [Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, NY (United States)

    2012-09-15

    Objective: To assess and compare subregional and whole T1rho values (median ± interquartile range) of femorotibial cartilage and menisci in patients with doubtful (Kellgren–Lawrence (KL) grade 1) to severe (KL4) osteoarthritis (OA) at 3T. Materials and methods: 30 subjects with varying degrees of OA (KL1–4, 13 females, 17 males, mean age ± SD = 63.9 ± 13.1 years) were evaluated on a 3T MR scanner using a spin-lock-based 3D GRE sequence for T1rho mapping. Clinical proton density (PD)-weighted fast spin echo (FSE) images in sagittal (without fat saturation), axial, and coronal (fat-saturated) planes were acquired for cartilage and meniscus Whole-organ MR imaging score (WORMS) grading. Wilcoxon rank sum test was performed to determine whether there were any statistically significant differences between subregional and whole T1rho values of femorotibial cartilage and menisci in subjects with doubtful to severe OA. Results: Lateral (72 ± 10 ms, median ± interquartile range) and medial (65 ± 10 ms) femoral anterior cartilage subregions in moderate–severe OA subjects had significantly higher T1rho values (P < 0.05) than cartilage subregions and whole femorotibial cartilage in doubtful–minimal OA subjects. There were statistically significant differences in meniscus T1rho values of the medial posterior subregion of subjects with moderate–severe OA and T1rho values of all subregions and the whole meniscus in subjects with doubtful–minimal OA. When evaluated based on WORMS, statistically significant differences were identified in T1rho values between the lateral femoral anterior cartilage subregion in patients with WORMS5–6 (advanced degeneration) and whole femorotibial cartilage and all cartilage subregions in patients with WORMS0–1 (normal). Conclusion: T1rho values are higher in specific meniscus and femorotibial cartilage subregions. These findings suggest that regional damage of both femorotibial hyaline cartilage and menisci may be associated with

  4. Fibrous cartilage of human menisci is less shock-absorbing and energy-dissipating than hyaline cartilage.

    Science.gov (United States)

    Gaugler, Mario; Wirz, Dieter; Ronken, Sarah; Hafner, Mirjam; Göpfert, Beat; Friederich, Niklaus F; Elke, Reinhard

    2015-04-01

    To test meniscal mechanical properties such as the dynamic modulus of elasticity E* and the loss angle δ at two loading frequencies ω at different locations of the menisci and compare it to E* and δ of hyaline cartilage in indentation mode with spherical indenters. On nine pairs of human menisci, the dynamic E*-modulus and loss angle δ (as a measure of the energy dissipation) were determined. The measurements were performed at two different strain rates (slow sinusoidal and fast single impact) to show the strain rate dependence of the material. The measurements were compared to previous similar measurements with the same equipment on human hyaline cartilage. The resultant E* at fast indentation (median 1.16 MPa) was significantly higher, and the loss angle was significantly lower (median 10.2°) compared to slow-loading mode's E* and δ (median 0.18 MPa and 16.9°, respectively). Further, significant differences for different locations are shown. On the medial meniscus, the anterior horn shows the highest resultant dynamic modulus. In dynamic measurements with a spherical indenter, the menisci are much softer and less energy-dissipating than hyaline cartilage. Further, the menisci are stiffer and less energy-dissipating in the middle, intermediate part compared to the meniscal base. In compression, the energy dissipation of meniscus cartilage plays a minor role compared to hyaline cartilage. At high impacts, energy dissipation is less than on low impacts, similar to cartilage.

  5. Bone bruise of the knee associated with the lesions of anterior cruciate ligament and menisci on magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Jelić Đorđe

    2011-01-01

    Full Text Available Background/Aim. Bone bruise is a common finding in acutely injured knee examined by magnetic resonance (MR. The aim of the study was to determine the association of bone bruise frequency with postinjury lesions of anterior cruciate ligament (ACL and menisci. Bone bruise involves posttraumatic bone marrow change with hemorrhages, edema and microtrabecular fractures without disruption of adjacent cortices or articular cartilage. MR imaging is a method of choice for detecting bone bruises which can not be seen on conventional radiographic techniques. Methods. A representative review of 120 MR examinations for the acute knee trauma was conducted. All the patients were examined within one month of trauma. All MR examinations were performed by using a 0.3T MR unit. Results. Posttraumatic bone bruise was seen in 39 (32.5% patients out of 120. Three patients had fracture of the cortex, so-called “occult” fracture (not seen on plain radiography. We analyzed only bone bruises without these fractures of the cortex. Bone bruise was associated with the lesion of ACL in 27 (69% patients. In 28 (72% patients bone bruise was in combination with the lesion of menisci. Only two patients with bone bruise had neither ACL nor menisci lesions. There were 78 patients without bone bruise but 33 (43% of them had lesions of ACL and 49 (63% had lesions of menisci. Conclusion. Bone bruise is best seen in STIR (Short TI Inversion Recovery images and is very often found in acute knee trauma. Very often it is associated with posttraumatic lesions of ACL and menisci, so attention must be paid to this when bone bruise is seen. The difference in frequency of internal structures of the knee lesions in patients with bone bruise is highly statistically significant as compared to patients with no bone bruise.

  6. Estrutura e celularidade de meniscos frescos de coelhos (Oryctolagus cuniculus preservados em glicerina Structure and cellularity of the fresh menisci (Oryctolagus cuniculus of rabbits and the menisci preserved in glycerin

    Directory of Open Access Journals (Sweden)

    Liana M. Vilela

    2010-04-01

    Full Text Available No presente estudo foi avaliada a arquitetura tecidual, a população celular, assim como a integridade e a distribuição dos tipos celulares em meniscos frescos de coelhos e preservados em glicerina 98%. Foram analisados meniscos mediais de coelhos recém abatidos, que foram distribuídos em três grupos: o grupo MF (n=7, composto por meniscos frescos, correspondeu ao grupo controle; o grupo MG (n=7, composto por meniscos preservados em glicerina 98%, por 30 dias, e o grupo MR (n=7, por meniscos preservados em glicerina 98% e reidratados em NaCl 0,9%, por 12 horas. Em todos os meniscos foram identificados e quantificados os diferentes tipos celulares: fibroblastos/fibrócitos e condrócitos. A população celular foi estatisticamente semelhante nos três grupos de meniscos, sendo que os meniscos preservados, grupos MG e MR, apresentaram menor intensidade de coloração e retração das fibras colágenas, diminuição de volume e maior intensidade de coloração dos núcleos (condensação da cromatina, em relação aos meniscos frescos (MF, caracterizando o fenômeno de lise celular. A matriz fibrocartilaginosa dos meniscos preservados revelou- se bem preservada mantendo a arquitetura tecidual dos meniscos. Conclui-se que a glicerina 98% é uma opção de meio de preservação para meniscos objetivando aloenxerto, com matriz colágena desvitalizada.In the present study was evaluated the tissue architecture, the percentage of cellular population, as well as viability and distribution of cells in fresh menisci of rabbits and preserved in 98% glycerin. Were analyzed medial menisci of rabbits freshly slaughtered, which were distributed into three groups: the MF group (n=7, composed of fresh menisci, corresponded to the control group; the MG group (n=7, composed by menisci preserved in 98% glycerin, for 30 days, and the MR group (n=7 by menisci preserved in 98% glycerin and rehydrated in NaCl 0.9% for 12 hours. In all menisci were identified and

  7. Relationship between knee alignment and T1ρ values of articular cartilage and menisci in patients with knee osteoarthritis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ligong, E-mail: ligong.wang@hotmail.com [Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, NY 10016 (United States); School of Radiation Medicine and Protection, Medical College of Soochow University, School for Radiological and interdisciplinary Sciences (RAD-X), Soochow University, Suzhou, Jiangsu 215123 (China); Vieira, Renata La Rocca, E-mail: relarocca@gmail.com [Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, NY 10016 (United States); Rybak, Leon D., E-mail: Leon.Rybak@nyumc.org [Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, NY 10016 (United States); Babb, James S., E-mail: James.Babb@nyumc.org [Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, NY 10016 (United States); Chang, Gregory, E-mail: gregory.chang@nyumc.org [Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, NY 10016 (United States); Krasnokutsky, Svetlana, E-mail: Svetlana.Krasnokutsky@nyumc.org [Department of Rheumatology, New York University Hospital for Joint Diseases, 301 East 17th Street, New York, NY 10003 (United States); Abramson, Steven, E-mail: StevenB.Abramson@nyumc.org [Department of Rheumatology, New York University Hospital for Joint Diseases, 301 East 17th Street, New York, NY 10003 (United States); and others

    2013-11-01

    Objective: To assess the relationship between knee alignment and subregional T1ρ values of the femorotibial cartilage and menisci in patients with mild (Kellgren–Lawrence grade 1) to moderate (KL3) osteoarthritis (OA) at 3 T. Materials and methods: 26 subjects with a clinical diagnosis of KL1-3 OA were included and subdivided into three subgroups: varus, valgus, and neutral. All subjects were evaluated on a 3 T MR scanner. Mann–Whitney and Wilcoxon signed rank tests were performed to determine any statistically significant differences in subregional T1ρ values of femorotibial cartilage and menisci among the three subgroups of KL1-3 OA patients. Results: Medial femoral anterior cartilage subregion in varus group had significantly higher (p < 0.05) T1ρ values than all cartilage subregions in valgus group. Medial tibial central cartilage subregion had significantly higher T1ρ values (p < 0.05) than lateral tibial central cartilage subregion in varus group. The posterior horn of the medial meniscus in neutral group had significantly higher T1ρ values (p < 0.0029) than all meniscus subregions in valgus group. Conclusion: There exists some degree of association between knee alignment and subregional T1ρ values of femorotibial cartilage and menisci in patients with clinical OA.

  8. Do Not Hallow until You Are out of the Wood! Ultrasonographic Detection of CPP Crystal Deposits in Menisci: Facts and Pitfalls

    Science.gov (United States)

    Filippou, Georgios; Adinolfi, Antonella; Bozios, Panagiotis; Lorenzini, Sauro; Picerno, Valentina; Di Sabatino, Valentina; Bertoldi, Ilaria; Gambera, Dario; Galeazzi, Mauro; Frediani, Bruno

    2013-01-01

    Purpose. Ultrasonography (US) has been demonstrated to be an important tool in the diagnosis of calcium pyrophosphate (CPP) crystal deposition disease. The aim of our study was to individuate and describe possible pitfalls in US detection of such deposits in menisci. Patients and Methods. We enrolled all patients waiting to undergo knee replacement surgery due to osteoarthritis, for one-month period. Each patient underwent US examination of the knee, focusing on the menisci. After surgery, the menisci were examined by US, macroscopically and microscopically, using the microscopic analysis as the gold standard for CPP deposition. Results. 11 menisci of 6 patients have been studied. Ex vivo examination of menisci performed better in CPP identification than in vivo examination. The possible reasons of misinterpretation or misdiagnosis of the in vivo exam were identified and are extensively described in the paper. Also a new sign of CPP crystal deposits was found. Conclusions. This study permitted to highlight some difficulties in CPP crystal detection by US in menisci. Further studies are needed to define completely US CPP crystal aspect and to improve the sensibility and specificity of US in CPP deposition diagnosis. PMID:23970829

  9. Do Not Hallow until You Are out of the Wood! Ultrasonographic Detection of CPP Crystal Deposits in Menisci: Facts and Pitfalls

    Directory of Open Access Journals (Sweden)

    Georgios Filippou

    2013-01-01

    Full Text Available Purpose. Ultrasonography (US has been demonstrated to be an important tool in the diagnosis of calcium pyrophosphate (CPP crystal deposition disease. The aim of our study was to individuate and describe possible pitfalls in US detection of such deposits in menisci. Patients and Methods. We enrolled all patients waiting to undergo knee replacement surgery due to osteoarthritis, for one-month period. Each patient underwent US examination of the knee, focusing on the menisci. After surgery, the menisci were examined by US, macroscopically and microscopically, using the microscopic analysis as the gold standard for CPP deposition. Results. 11 menisci of 6 patients have been studied. Ex vivo examination of menisci performed better in CPP identification than in vivo examination. The possible reasons of misinterpretation or misdiagnosis of the in vivo exam were identified and are extensively described in the paper. Also a new sign of CPP crystal deposits was found. Conclusions. This study permitted to highlight some difficulties in CPP crystal detection by US in menisci. Further studies are needed to define completely US CPP crystal aspect and to improve the sensibility and specificity of US in CPP deposition diagnosis.

  10. Direct Current Hopping Conductivity in One-Dimensional Nanometre Systems

    Institute of Scientific and Technical Information of China (English)

    宋祎璞; 徐慧; 罗峰

    2003-01-01

    A one-dimensional random nanocrystalline chain model is established. A dc electron-phonon-field conductance model of electron tunnelling transfer is set up, and a new dc conductance formula in one-dimensional nanometre systems is derived. By calculating the dc conductivity, the relationship among the electric field, temperature and conductivity is analysed, and the effect of the crystalline grain size and the distortion of interfacial atoms on the dc conductance is discussed. The result shows that the nanometre system appears the characteristic of negative differential dependence of resistance and temperature at low temperature. The dc conductivity of nanometre systems varies with the change of electric field and trends to rise as the crystalline grain size increases and to decrease as the distorted degree of interfacial atoms increases.

  11. The biological response to nanometre-sized polymer particles

    Science.gov (United States)

    Liu, Aiqin; Richards, Laura; Bladen, Catherine L.; Ingham, Eileen; Fisher, John; Tipper, Joanne L.

    2015-01-01

    Recently, nanometre-sized UHMWPE particles generated from hip and knee replacements have been identified in vitro and in vivo. UHMWPE particles in the 0.1–1.0 μm size range have been shown to be more biologically active than larger particles, provoking an inflammatory response implicated in late aseptic loosening of total joint replacements. The biological activity of nanometre-sized particles has not previously been studied. The biological response to clinically-relevant UHMWPE wear particles including nanometre-sized and micrometre-sized, along with polystyrene particles (FluoSpheres 20 nm, 60 nm, 200 nm and 1.0 μm), and nanometre-sized model polyethylene particles (Ceridust 3615®), was determined in terms of osteolytic cytokine release from primary human peripheral blood mononuclear cells (PBMNCs). Nanometre-sized UHMWPE wear particles, nanometre-sized Ceridust 3615® and 20 nm FluoSpheres had no significant effect on TNF-α, IL-1β, IL-6 and IL-8 release from PBMNCs at a concentration of 100 μm3 particles per cell after 12 and 24 h. The micrometre-size UHMWPE wear particles (0.1–1.0 μm) and 60 nm, 200 nm and 1.0 μm FluoSpheres caused significantly elevated osteolytic cytokine release from PBMNCs. These results indicated that particles below circa 50 nm fail to activate PBMNCs and that particle size, composition and morphology played a crucial role in cytokine release by particle stimulated macrophages. PMID:26004221

  12. A Novel Nanometric Fault Tolerant Reversible Subtractor Circuit

    Directory of Open Access Journals (Sweden)

    Mozhgan Shiri

    2012-11-01

    Full Text Available Reversibility plays an important role when energy efficient computations are considered. Reversible logic circuits have received significant attention in quantum computing, low power CMOS design, optical information processing and nanotechnology in the recent years. This study proposes a new fault tolerant reversible half-subtractor and a new fault tolerant reversible full-subtractor circuit with nanometric scales. Also in this paper we demonstrate how the well-known and important, PERES gate and TR gate can be synthesized from parity preserving reversible gates. All the designs have nanometric scales.

  13. Material properties of individual menisci and their attachments obtained through inverse FE-analysis.

    Science.gov (United States)

    Freutel, Maren; Galbusera, Fabio; Ignatius, Anita; Dürselen, Lutz

    2015-06-01

    Meniscal properties for computational methods have already been proposed. However, it is well known that there is high intra subject variability in the material properties of soft tissues and that disruption of the fiber network alters the biomechanics of the meniscus. Therefore, the objective of this study was to establish a non invasive method to determine the material properties of the individual menisci and their attachments using inverse FE-analyses. In a previous study, the 3D displacements of the meniscus and its attachments under axial joint loads were determined for intact porcine knees. To simulate the experimental response in individual FE-analyses (n=5), an anisotropic, hyperelastic meniscus matrix was embedded in a poroelastic model. During a particle swarm optimization, the difference between the force applied to the meniscus during the experiment and the femoral surface reaction force of the FE model at equilibrium was minimized by varying four material parameters. Afterwards, a prediction error was determined to describe how well the material parameter fit to each of the three displacement directions. Additionally, the stresses occurring in the meniscus were evaluated. The error of the material parameter optimization was on average 6.5±4.4%. The best fitting material parameter combination revealed an error of 1.2%. The highest stresses occurred in the region between the pars intermedia and posterior horn of the meniscus. The individual material properties of the meniscus were successfully obtained with a combination of previously reported, noninvasively measured 3D displacements and inverse FE-analyses. The methodology presented in this study is a promising contribution to the detection of degeneration within the meniscus. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Lithographic mirrors: measured with sub-nanometre accuracy

    NARCIS (Netherlands)

    Mols, B.

    2004-01-01

    Future generations of microchips will probably be produced using extreme ultraviolet light with a wavelength of thirteen nanometres. Optical lenses will no longer be suitable for the manufacturing process because they absorb the light at such short wavelengths. Mirrors will have to be used instead.

  15. Influence of nanometric silicon carbide on phenolic resin composites properties

    Indian Academy of Sciences (India)

    GEORGE PELIN; CRISTINA-ELISABETA PELIN; ADRIANA STEFAN; ION DINC\\u{A}; ANTON FICAI; ECATERINA ANDRONESCU; ROXANA TRUSC\\u{A}

    2016-06-01

    This paper presents a preliminary study on obtaining and characterization of phenolic resin-based composites modified with nanometric silicon carbide. The nanocomposites were prepared by incorporating nanometric silicon carbide (nSiC) into phenolic resin at 0.5, 1 and 2 wt% contents using ultrasonication to ensure uniform dispersion of the nanopowder, followed by heat curing of the phenolic-based materials at controlled temperature profile up to 120$^{\\circ}$C. The obtained nanocomposites were characterized by FTIR spectroscopy and scanning electron microscopy analysis and evaluated in terms of mechanical, tribological and thermal stability under load. The results highlight the positive effect of the nanometric silicon carbide addition in phenolic resin on mechanical, thermo-mechanical and tribological performance, improving their strength, stiffness and abrasive properties. The best results were obtained for 1 wt% nSiC, proving that this value is the optimum nanometric silicon carbide content. The results indicate that these materials could be effectively used to obtain ablative or carbon–carbon composites in future studies.

  16. Three-month performance evaluation of the Nanometrics, Inc., Libra Satellite Seismograph System in the northern California Seismic Network

    Science.gov (United States)

    Oppenheimer, David H.

    2000-01-01

    In 1999 the Northern California Seismic Network (NCSN) purchased a Libra satellite seismograph system from Nanometrics, Inc to assess whether this technology was a cost-effective and robust replacement for their analog microwave system. The system was purchased subject to it meeting the requirements, criteria and tests described in Appendix A. In early 2000, Nanometrics began delivery of various components of the system, such as the hub and remote satellite dish and mounting hardware, and the NCSN installed and assembled most equipment in advance of the arrival of Nanometrics engineers to facilitate the configuration of the system. The hub was installed in its permanent location, but for logistical reasons the "remote" satellite hardware was initially configured at the NCSN for testing. During the first week of April Nanometrics engineers came to Menlo Park to configure the system and train NCSN staff. The two dishes were aligned with the satellite, and the system was fully operational in 2 days with little problem. Nanometrics engineers spent the remaining 3 days providing hands-on training to NCSN staff in hardware/software operation, configuration, and maintenance. During the second week of April 2000, NCSN staff moved the entire remote system of digitizers, dish assembly, and mounting hardware to Mammoth Lakes, California. The system was reinstalled at the Mammoth Lakes water treatment plant and communications successfully reestablished with the hub via the satellite on 14 April 2000. The system has been in continuous operation since then. This report reviews the performance of the Libra system for the three-month period 20 April 2000 through 20 July 2000. The purpose of the report is to assess whether the system passed the acceptance tests described in Appendix A. We examine all data gaps reported by NCSN "gap list" software and discuss their cause.

  17. Comparison of Kinematics and Tibiofemoral Contact Pressures for Native and Transplanted Lateral Menisci

    Science.gov (United States)

    McCulloch, Patrick C.; Dolce, Donald; Jones, Hugh L.; Gale, Andrea; Hogen, Michael G.; Alder, Jason; Palmer, Jeremiah E.; Noble, Philip C.

    2016-01-01

    Background: Lateral meniscus transplantation is a proven treatment option for the meniscus-deficient knee, yet little is known about meniscal kinematics, strain, and tibiofemoral contact pressure changes after transplantation or the effect of altered root position in lateral meniscus transplantation. Purpose: To compare the native lateral meniscal kinematics, strain, and tibiofemoral contact pressures to a best-case scenario meniscus transplant with perfectly matched size and position and to determine how sensitive these factors are to subtle changes in shape and position by using a nonanatomic meniscus transplant position. Study Design: Controlled laboratory study. Methods: The lateral menisci of 8 cadaveric knees were circumferentially implanted with radiopaque spherical markers. They were mounted to a testing apparatus applying muscle and ground-reaction forces. The meniscus was evaluated at 0°, 30°, 90°, and 115° of knee flexion using Roentgen stereophotogrammetric analysis (RSA), with a pressure sensor affixed to the lateral tibial plateau. Measurements were recorded for 3 states: the native lateral meniscus, an anatomic autograft transplant, and a nonanatomic autograft transplant with an anteriorized posterior root position. Results: After transplantation, there was less posterior displacement in both the anatomic and nonanatomic transplant states compared with the native meniscus, but this was not significant. The largest lateral translation in the native state was 2.38 ± 1.58 mm at the anterolateral region from 0° to 90°, which was increased to 3.28 ± 1.39 mm (P = .25) and 3.12 ± 1.18 mm (P = .30) in the anatomic and nonanatomic transplant states, respectively. Internal deformations of the transplant states were more constrained, suggesting less compliance. The native meniscus distributed load over 223 mm2, while both the anatomic (160 mm2) and nonanatomic (102 mm2) states concentrated pressure anteriorly to the tibial plateau centroid. Conclusion

  18. Nanometric holograms based on a topological insulator material

    Science.gov (United States)

    Yue, Zengji; Xue, Gaolei; Liu, Juan; Wang, Yongtian; Gu, Min

    2017-05-01

    Holography has extremely extensive applications in conventional optical instruments spanning optical microscopy and imaging, three-dimensional displays and metrology. To integrate holography with modern low-dimensional electronic devices, holograms need to be thinned to a nanometric scale. However, to keep a pronounced phase shift modulation, the thickness of holograms has been generally limited to the optical wavelength scale, which hinders their integration with ultrathin electronic devices. Here, we break this limit and achieve 60 nm holograms using a topological insulator material. We discover that nanometric topological insulator thin films act as an intrinsic optical resonant cavity due to the unequal refractive indices in their metallic surfaces and bulk. The resonant cavity leads to enhancement of phase shifts and thus the holographic imaging. Our work paves a way towards integrating holography with flat electronic devices for optical imaging, data storage and information security.

  19. Nanometre-scale electronics with III-V compound semiconductors.

    Science.gov (United States)

    del Alamo, Jesús A

    2011-11-16

    For 50 years the exponential rise in the power of electronics has been fuelled by an increase in the density of silicon complementary metal-oxide-semiconductor (CMOS) transistors and improvements to their logic performance. But silicon transistor scaling is now reaching its limits, threatening to end the microelectronics revolution. Attention is turning to a family of materials that is well placed to address this problem: group III-V compound semiconductors. The outstanding electron transport properties of these materials might be central to the development of the first nanometre-scale logic transistors.

  20. Atomic Study on Some Problems in Nanometric Cutting Mechanism

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An investigation of some problems such as chip formation and surface generation in nanometric cutting mechanism based on molecular dynamics(MD) simulation is presented.It shows that chip formation is similar to that observed in macro-scale cutting.The movement of some micro-dislocation is the main cause of formation of chip and surface.Surface generation is notably affected by very small cutting force vibration.The highest stress appears in tool cutting edge,and it may cause wear,so it is necessary to build a MD model of tool wear.

  1. Cerium oxide based nanometric powders: synthesis and characterization

    Directory of Open Access Journals (Sweden)

    Ninić M.

    2007-01-01

    Full Text Available Nanometric powders of solid solutions of cerium oxide were obtained by a modified glycine nitrate procedure. Solid solutions of the host compound CeO2 with one or more dopants in the lattice were synthesized. Rare earth cations (Re=Yb, Gd and Sm were added to ceria in total concentration of x= 0.2 that was kept constant. The criterion in doping was to keep the value of lattice parameter of ceria unchanged. The lattice parameters were calculated by using the model that takes into account the existence of oxygen vacancies in the structure.

  2. Nanometre-scale thermometry in a living cell.

    Science.gov (United States)

    Kucsko, G; Maurer, P C; Yao, N Y; Kubo, M; Noh, H J; Lo, P K; Park, H; Lukin, M D

    2013-08-01

    Sensitive probing of temperature variations on nanometre scales is an outstanding challenge in many areas of modern science and technology. In particular, a thermometer capable of subdegree temperature resolution over a large range of temperatures as well as integration within a living system could provide a powerful new tool in many areas of biological, physical and chemical research. Possibilities range from the temperature-induced control of gene expression and tumour metabolism to the cell-selective treatment of disease and the study of heat dissipation in integrated circuits. By combining local light-induced heat sources with sensitive nanoscale thermometry, it may also be possible to engineer biological processes at the subcellular level. Here we demonstrate a new approach to nanoscale thermometry that uses coherent manipulation of the electronic spin associated with nitrogen-vacancy colour centres in diamond. Our technique makes it possible to detect temperature variations as small as 1.8 mK (a sensitivity of 9 mK Hz(-1/2)) in an ultrapure bulk diamond sample. Using nitrogen-vacancy centres in diamond nanocrystals (nanodiamonds), we directly measure the local thermal environment on length scales as short as 200 nanometres. Finally, by introducing both nanodiamonds and gold nanoparticles into a single human embryonic fibroblast, we demonstrate temperature-gradient control and mapping at the subcellular level, enabling unique potential applications in life sciences.

  3. Nanometre-scale thermometry in a living cell

    Science.gov (United States)

    Kucsko, G.; Maurer, P. C.; Yao, N. Y.; Kubo, M.; Noh, H. J.; Lo, P. K.; Park, H.; Lukin, M. D.

    2013-08-01

    Sensitive probing of temperature variations on nanometre scales is an outstanding challenge in many areas of modern science and technology. In particular, a thermometer capable of subdegree temperature resolution over a large range of temperatures as well as integration within a living system could provide a powerful new tool in many areas of biological, physical and chemical research. Possibilities range from the temperature-induced control of gene expression and tumour metabolism to the cell-selective treatment of disease and the study of heat dissipation in integrated circuits. By combining local light-induced heat sources with sensitive nanoscale thermometry, it may also be possible to engineer biological processes at the subcellular level. Here we demonstrate a new approach to nanoscale thermometry that uses coherent manipulation of the electronic spin associated with nitrogen-vacancy colour centres in diamond. Our technique makes it possible to detect temperature variations as small as 1.8 mK (a sensitivity of 9 mK Hz-1/2) in an ultrapure bulk diamond sample. Using nitrogen-vacancy centres in diamond nanocrystals (nanodiamonds), we directly measure the local thermal environment on length scales as short as 200 nanometres. Finally, by introducing both nanodiamonds and gold nanoparticles into a single human embryonic fibroblast, we demonstrate temperature-gradient control and mapping at the subcellular level, enabling unique potential applications in life sciences.

  4. Deep subwavelength nanometric image reconstruction using Fourier domain optical normalization

    Institute of Scientific and Technical Information of China (English)

    Jing Qin; Richard M Silver; Bryan M Barnes; Hui Zhou; Ronald G Dixson; Mark-Alexander Henn

    2016-01-01

    Quantitative optical measurements of deep subwavelength,three-dimensional (3D),nanometric structures with sensitivity to sub-nanometer details address a ubiquitous measurement challenge.A Fourier domain normalization approach is used in the Fourier optical imaging code to simulate the full 3D scattered light field of nominally 15 nm-sized structures,accurately replicating the light field as a function of the focus position.Using the full 3D light field,nanometer scale details such as a 2 nm thin conformal oxide and nanometer topography are rigorously fitted for features less than one-thirtiethof the wavelength in size.The densely packed structures are positioned nearly an order of magnitude closer than the conventional Rayleigh resolution limit and can be measured with sub-nanometer parametric uncertainties.This approach enables a practical measurement sensitivity to size variations of only a few atoms in size using a high-throughput optical configuration with broad application in measuring nanometric structures and nanoelectronic devices.

  5. Ultrasonic cavitation for obtainment of nanometric sized particles

    Science.gov (United States)

    Santos, A.; Guzmán, R.; Espinosa, J.; Estrada, J.

    2016-02-01

    This project aims to determine the possibility of obtaining nanometric size particles of aluminium oxide (Al2O3) and titanium dioxide (TiO2) from commercial micron-sized powders, through the physical principle of ultrasonic cavitation, in order to be used as supply material in coatings made through a process of thermal spray by flame. The tests are performed on a Hielscher UIP 1000hd Ultrasonics equipment, in a 20 micron wave amplitude and in times of 6, 8, 12, 18 and 24 hours. The determination of the particle size is done through image processing using ImageJ software, obtained by the technique of scanning electron microscopy (SEM); while the elemental composition of the processed samples is analyzed through the technique of energy dispersing spectroscopy (EDS). The results show that Al2O3 and TiO2 have a reduction behaviour of the particles size after being subjected to ultrasonic cavitation, however is only reached the nanometric size in the TiO2 samples.

  6. Nanometric Gouge in High-Speed Shearing Experiments: Superplasticity?

    Science.gov (United States)

    Green, H. W.; Lockner, D. A.; Bozhilov, K. N.; Maddon, A.; Beeler, N. M.; Reches, Z.

    2010-12-01

    High-speed shearing experiments on solid rock samples typically generate a gouge with sub-micron grain size that appears to control the frictional resistance at velocities approaching 1 m/s (Reches & Lockner, Nature, in press). We conducted experiments on Kasota dolomite samples and observed profound weakening (friction drops from ~0.8 to ~ 0.2) under earthquake conditions (up to slip-velocity ~ 0.95 m/s and normal stress 28.4 MPa). During these runs the experimental fault had T ≥ 800°C and developed a shining, dark surface. We report here analysis of such a surface with scanning electron microscopy (SEM) and atomic force microscopy (AFM). SEM analysis shows a slickensided gouge made up of particles all ≤ 50nm with a large fraction ≤ 20nm. The spacing of the slickenside striations is less than 1 µm. Over large areas of the slickensided surface the nanometric gouge has been replaced by an undeformed, interlocking crystalline pavement of 100-300 nm grain size. Qualitative chemical analysis of this pavement surface by energy-dispersive X-ray spectroscopy reveals only a weak carbon peak, suggesting that the dolomite has been decarbonated. The development of a “pavement” of grain size ~200 nm in our experiments is remarkably similar to the observations of Han et al. (JGR, 2010, Fig. 14(d)). However, their experiments either did not develop such a nanometric gouge or it was completely replaced by the coarser pavement. These present observations of nanometric gouge that recrystallizes during the short time interval of elevated temperature following termination of deformation are reminiscent of the nanometric “gouge” produced in very high-pressure experiments (1-14 GPa) that have failed by transformation-induced faulting during the olivine-spinel transformation (Green and Burnley, Nature, 1989; Green et al., Nature, 1990). In the high-pressure experiments, the gouge consists of a nanocrystalline aggregate of the spinel phase that flowed at very high strain

  7. Molecular dynamics simulations of thermal effects in nanometric cutting process

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Understanding the basic action of how material removing in nanoscale is a critical issue of producing well-formed components.In order to clarify thermal effects on material removal at atomic level,molecular dynamics(MD)simulations of nanometric cutting of mono-crystalline copper are performed with Morse,EAM and Tersoff potential.The effects of cutting speed on temperature distribution are investigated.The simulation results demonstrate that the temperature distribution shows a roughly concentric shape around shear zone and a steep temperature gradient lies in diamond tool,a relative high temperature is located in shear zone and machined surface,but the highest temperature is found in chip.At a high cutting speed mode,the atoms in shear zone with high temperature implies a large stress is built up in a local region.

  8. Surface conductivity measurements in nanometric to micrometric foam films.

    Science.gov (United States)

    Bonhomme, Oriane; Mounier, Anne; Simon, Gilles; Biance, Anne-Laure

    2015-05-20

    Foam films (a liquid lamella in air covered by surfactants) are tools of choice for nanofluidic characterization as they are intrinsically nanometric. Their size is indeed fixed by a balance between external pressure and particular molecular interactions in the vicinity of interfaces. To probe the exact nature of these interfaces, different characterizations can be performed. Among them, conductivity in confined systems is a direct probe of the electrostatic environment in the vicinity of the surface. Therefore, we designed a dedicated experiment to measure this conductivity in a cylindrical bubble coupled to interferometry for film thickness characterization. We then show that this conductivity depends on the surfactant nature. These conductivity measurements have been performed in an extremely confined system, the so called Newton black foam films. Unexpectedly in this case, a conductivity close to surface conductivity is recovered.

  9. Dynamics of polynucleotide transport through nanometre-scale pores

    CERN Document Server

    Meller, A

    2003-01-01

    The transport of biopolymers through large membrane channels is a ubiquitous process in biology. It is central to processes such as gene transfer by transduction and RNA transport through nuclear pore complexes. The transport of polymers through nanoscopic channels is also of interest to physicists and chemists studying the effects of steric, hydrodynamic, and electrostatic interactions between polymers and confining walls. Single-channel ion current measurements have been recently used to study the transport of biopolymers, and in particular single-stranded DNA and RNA molecules, through nanometre-size channels. Under the influence of an electric field, the negatively charged polynucleotides can be captured and drawn through the channel in a process termed 'translocation'. During translocation, the ion current flowing through the channel is mostly blocked, indicating the presence of the polymer inside the channel. The current blockades were found to be sensitive to the properties of the biopolymers such as t...

  10. Three-dimensional micro- and nanometre composite aluminium patterns

    Institute of Scientific and Technical Information of China (English)

    Zhao Xiao-Wei; Zhang Zeng-Xing; Xiang Yan-Juan; Zhou Wei-Ya; Wang Gang; Jiang Peng; Gao Yan; Wang Jian-Xiong; Song Li; Liu Dong-Fang; Liu Li-Feng; Dou Xin-Yuan; Luo Shu-Dong

    2005-01-01

    Three-dimensional micro- and nanometre composite aluminium patterns are constructed on Al substrate by using photolithography, reactive ion etching and anodization. A layer of patterned SiO2 mask is introduced as resist on the surface of Al foil, and during anodization the tilted nanopores and remaining Al microstructure are formed underneath the SiO2 mask. The existence of SiO2 mask leads to the deflection of electric field and effect on the transportation of ions, which results in the formation of laterally tilted nanopores, while the nanopores go down directly when being far from the boundaries of SiO2. The vertical and lateral anodization processes proceeding simultaneously construct the Al microstructure under the patterned SiO2 mask.

  11. Nanometric Finishing on Biomedical Implants by Abrasive Flow Finishing

    Science.gov (United States)

    Subramanian, Kavithaa Thirumalai; Balashanmugam, Natchimuthu; Shashi Kumar, Panaghra Veeraiah

    2016-01-01

    Abrasive flow finishing (AFF) is a non-conventional finishing technique that offers better accuracy, efficiency, consistency, economy in finishing of complex/difficult to machine materials/components and provides the possibility of effective automation as aspired by the manufacturing sector. The present study describes the finishing of a hip joint made of ASTM grade Co-Cr alloy by Abrasive Flow Machining (AFM) process. The major input parameters of the AFF process were optimized for achieving nanometric finishing of the component. The roughness average (Ra) values were recorded during experimentation using surface roughness tester and the results are discussed in detail. The surface finished hip joints were characterized using Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and residual stress analysis using X-Ray Diffraction (XRD). The discussion lays emphasis on the significance, efficacy and versatile nature of the AFF process in finishing of bio-medical implants.

  12. A Novel Nanometric Reversible Signed Divider with Overflow Checking Capability

    Directory of Open Access Journals (Sweden)

    Faraz Dastan

    2012-03-01

    Full Text Available One of the best approaches for designing future computers is that we use reversible logic. Reversible logic circuits have lower power consumption than the common circuits, used in computers nowadays. In this study we propose a new reversible division circuit. This reversible division circuit is signed divider and has an overflow checking capability. Among the designed and proposed reversible division circuits, our proposed division circuit is the first reversible signed divider with overflow checking capability which has been designed. In this circuit we use some reversible components like reversible parallel adder, reversible left-shift register, reversible multiplexer, reversible n-bit register and reversible n-bit register with parallel load line. In this paper all the scales are in the nanometric area.

  13. Design of the Efficient Nanometric Reversible Subtractor Circuit

    Directory of Open Access Journals (Sweden)

    Mozhgan Shiri

    2012-11-01

    Full Text Available Reversible logic has comprehensive applications in communications, quantum computing, low power VLSI design, computer graphics, cryptography, nanotechnology, and optical computing. It has received significant attention in low power dissipating circuit design in the past few years. While several researchers have inspected the design of reversible logic units, there is not much reported works on reversible subtractors. In this paper we proposed the quantum equivalent circuit for SRK gate and we have computed the quantum cost of SRK gate. We also showed that how SRK gate can work singly as a half-subtractor circuit. It is being tried to design the circuit optimal in terms of number of reversible gates, number of garbage outputs, number of constant inputs, and quantum cost with compared to the existing circuits. At last we proposed an implementation of the new full-subtractor circuit based on SRK gate. All the designs have nanometric scales.

  14. Contact Angle Effects on Pore and Corner Arc Menisci in Polygonal Capillary Tubes Studied with the Pseudopotential Multiphase Lattice Boltzmann Model

    Directory of Open Access Journals (Sweden)

    Soyoun Son

    2016-02-01

    Full Text Available In porous media, pore geometry and wettability are determinant factors for capillary flow in drainage or imbibition. Pores are often considered as cylindrical tubes in analytical or computational studies. Such simplification prevents the capture of phenomena occurring in pore corners. Considering the corners of pores is crucial to realistically study capillary flow and to accurately estimate liquid distribution, degree of saturation and dynamic liquid behavior in pores and in porous media. In this study, capillary flow in polygonal tubes is studied with the Shan-Chen pseudopotential multiphase lattice Boltzmann model (LBM. The LB model is first validated through a contact angle test and a capillary intrusion test. Then capillary rise in square and triangular tubes is simulated and the pore meniscus height is investigated as a function of contact angle θ. Also, the occurrence of fluid in the tube corners, referred to as corner arc menisci, is studied in terms of curvature versus degree of saturation. In polygonal capillary tubes, the number of sides leads to a critical contact angle θc which is known as a key parameter for the existence of the two configurations. LBM succeeds in simulating the formation of a pore meniscus at θ > θc or the occurrence of corner arc menisci at θ < θc. The curvature of corner arc menisci is known to decrease with increasing saturation and decreasing contact angle as described by the Mayer and Stoewe-Princen (MS-P theory. We obtain simulation results that are in good qualitative and quantitative agreement with the analytical solutions in terms of height of pore meniscus versus contact angle and curvature of corner arc menisci versus saturation degree. LBM is a suitable and promising tool for a better understanding of the complicated phenomena of multiphase flow in porous media.

  15. Nanometric resolution magnetic resonance imaging methods for mapping functional activity in neuronal networks.

    Science.gov (United States)

    Boretti, Albert; Castelletto, Stefania

    2016-01-01

    This contribution highlights and compares some recent achievements in the use of k-space and real space imaging (scanning probe and wide-filed microscope techniques), when applied to a luminescent color center in diamond, known as nitrogen vacancy (NV) center. These techniques combined with the optically detected magnetic resonance of NV, provide a unique platform to achieve nanometric magnetic resonance imaging (MRI) resolution of nearby nuclear spins (known as nanoMRI), and nanometric NV real space localization. •Atomic size optically detectable spin probe.•High magnetic field sensitivity and nanometric resolution.•Non-invasive mapping of functional activity in neuronal networks.

  16. Novel designs of nanometric parity preserving reversible compressor

    Science.gov (United States)

    Shoaei, Soghra; Haghparast, Majid

    2014-08-01

    Reversible logic is a new field of study that has applications in optical information processing, low power CMOS design, DNA computing, bioinformatics, and nanotechnology. Low power consumption is a basic issue in VLSI circuits today. To prevent the distribution of errors in the quantum circuit, the reversible logic gates must be converted into fault-tolerant quantum operations. Parity preserving is used to realize fault tolerant in this circuits. This paper proposes a new parity preserving reversible gate. We named it NPPG gate. The most significant aspect of the NPPG gate is that it can be used to produce parity preserving reversible full adder circuit. The proposed parity preserving reversible full adder using NPPG gate is more efficient than the existing designs in term of quantum cost and it is optimized in terms of number of constant inputs and garbage outputs. Compressors are of importance in VLSI and digital signal processing applications. Effective VLSI compressors reduce the impact of carry propagation of arithmetic operations. They are built from the full adder blocks. We also proposed three new approaches of parity preservation reversible 4:2 compressor circuits. The third design is better than the previous two in terms of evaluation parameters. The important contributions have been made in the literature toward the design of reversible 4:2 compressor circuits; however, there are not efforts toward the design of parity preservation reversible 4:2 compressor circuits. All the scales are in the nanometric criteria.

  17. Growth and structure of nanometric iron oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Guiot, E.; Gota, S.; Henriot, M.; Gautier-Soyer, M. [CEA SACLAY, Gif sur Yvette (France); Lefebvre, S. [Centre Univ. Paris Sud, Orsay (France)

    1998-12-31

    Nanometric films of iron oxides (Fe{sub 3}O{sub 4}, {alpha} and {gamma} Fe{sub 2}O{sub 3}) of high crystalline order and purity are epitaxially grown on {alpha}-Al{sub 2}O{sub 3}(0001) by atomic oxygen assisted MBE. A complete characterization of the films structure has been performed by in situ LEED and RHEED, and ex situ GIXRD using synchrotron radiation. The films grown at room temperature and post annealed at 400 C and 700 C (p{sub O{sub 2}} = 10{sup {minus}6} Torr) are respectively metastable {gamma}-Fe{sub 2}O{sub 3} (111) and {alpha}-Fe{sub 2}O{sub 3} (0001). For a substrate temperature of 450 C during growth, Fe{sub 3}O{sub 4} (111) is directly obtained. GIXRD shows an in-plane expansion of the films, which decreases with thickness (0.8 and 0.2% for film thickness of 20 and 80 {angstrom}, respectively).

  18. Engineering nanometre-scale coherence in soft matter

    Science.gov (United States)

    Liu, Chaoren; Xiang, Limin; Zhang, Yuqi; Zhang, Peng; Beratan, David N.; Li, Yueqi; Tao, Nongjian

    2016-10-01

    Electronic delocalization in redox-active polymers may be disrupted by the heterogeneity of the environment that surrounds each monomer. When the differences in monomer redox-potential induced by the environment are small (as compared with the monomer-monomer electronic interactions), delocalization persists. Here we show that guanine (G) runs in double-stranded DNA support delocalization over 4-5 guanine bases. The weak interaction between delocalized G blocks on opposite DNA strands is known to support partially coherent long-range charge transport. The molecular-resolution model developed here finds that the coherence among these G blocks follows an even-odd orbital-symmetry rule and predicts that weakening the interaction between G blocks exaggerates the resistance oscillations. These findings indicate how sequence can be exploited to change the balance between coherent and incoherent transport. The predictions are tested and confirmed using break-junction experiments. Thus, tailored orbital symmetry and structural fluctuations may be used to produce coherent transport with a length scale of multiple nanometres in soft-matter assemblies, a length scale comparable to that of small proteins.

  19. Marine Polysaccharide Networks and Diatoms at the Nanometric Scale

    Directory of Open Access Journals (Sweden)

    Tea Mišić Radić

    2013-10-01

    Full Text Available Despite many advances in research on photosynthetic carbon fixation in marine diatoms, the biophysical and biochemical mechanisms of extracellular polysaccharide production remain significant challenges to be resolved at the molecular scale in order to proceed toward an understanding of their functions at the cellular level, as well as their interactions and fate in the ocean. This review covers studies of diatom extracellular polysaccharides using atomic force microscopy (AFM imaging and the quantification of physical forces. Following a brief summary of the basic principle of the AFM experiment and the first AFM studies of diatom extracellular polymeric substance (EPS, we focus on the detection of supramolecular structures in polysaccharide systems produced by marine diatoms. Extracellular polysaccharide fibrils, attached to the diatom cell wall or released into the surrounding seawater, form distinct supramolecular assemblies best described as gel networks. AFM makes characterization of the diatom polysaccharide networks at the micro and nanometric scales and a clear distinction between the self-assembly and self-organization of these complex systems in marine environments possible.

  20. Nanometric Cutting of Silicon with an Amorphous-Crystalline Layered Structure: A Molecular Dynamics Study

    Science.gov (United States)

    Wang, Jinshi; Fang, Fengzhou; Zhang, Xiaodong

    2017-01-01

    Materials with specific nanometric layers are of great value in both theoretical and applied research. The nanometric layer could have a significant influence on the response to the mechanical loading. In this paper, the nanometric cutting on the layered systems of silicon has been studied by molecular dynamics. This kind of composite structure with amorphous layer and crystalline substrate is important for nanomachining. Material deformation, stress status, and chip formation, which are the key issues in nano-cutting, are analyzed. A new chip formation mechanism, i.e., the mixture of extrusion and shear, has been observed. In addition, from the perspective of engineering, some specific composite models show the desired properties due to the low subsurface damage or large material removal rate. The results enrich the cutting theory and provide guidance on nanometric machining.

  1. Microstructural characterization of CPPD and hydroxyapatite crystal depositions on human menisci

    Energy Technology Data Exchange (ETDEWEB)

    Katsamenis, Orestis L. [Bioengineering Research Group, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Department of Materials Science, University of Patras, 26504 Rio, Patras (Greece); Karoutsos, Vagelis [Department of Materials Science, University of Patras, 26504 Rio, Patras (Greece); Kontostanos, Konstantinos; Panagiotopoulos, Elias C. [Department of Orthopaedics, School of Medicine, University of Patras, 26500 Rio, Patras (Greece); Papadaki, Helen [Department of Anatomy-Histology-Embryology, School of Medicine, University of Patras, 26500 Rio, Patras (Greece); Bouropoulos, Nikolaos [Department of Materials Science, University of Patras, 26504 Rio, Patras (Greece); Foundation for Research and Technology, Hellas-Institute of Chemical Engineering and High Temperature Chemical Processes - FORTH/ICE-HT, P.O. Box 1414, GR-26504 Patras (Greece)

    2012-11-15

    Meniscus is a fibrocartilaginous tissue composed mainly of water and a dense elaborate collagen network with a predominantly circumferential alignment. Crystal formation and accumulation on meniscal tissue is frequently observed especially in elderly. In this study, we used X-ray diffraction (XRD), FTIR and FT-Raman for the structural identification of the depositions and Optical microscopy, Scanning Electron microscopy (SEM/EDX) and Atomic Force microscopy (AFM), in order to investigate the structural relationship between the crystal deposits and the collagen fibers of human meniscal tissues. We are reporting on the formation of intercalary ''colonies'' of Calcium Pyrophosphate Dihydrate (CPPD) crystals with two distinct morphologies corresponding to the monoclinic and the triclinic phase, as well as the formation of micro-aggregations composed of nano-crystalline HAP aggregations which are developed along the longitudinal axis of collagen fibers without extensively disturbing the collagens arrangement. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Synthesis and characterization of nanometric zinc oxide for a stationary phase in liquid chromatography

    Science.gov (United States)

    Gordillo-Delgado, F.; Soto-Barrera, C. C.; Plazas-Saldaña, J.

    2017-01-01

    The increasing demand for equipment to remove organic compounds in industry and research activity has led to evaluate nanometric zinc oxide (ZnO). In this work, we present the ZnO nanoparticles synthesis for reusing of discarded columns, as a low-cost alternative. The compound was obtained by sol-gel technique using zinc chloride and sodium hydroxide as precursors and a drying temperature of 169°C. An X-ray diffractometer was used to estimate the average particle size at 20.3±0.2nm the adsorption capacity was 0.0144L/g and the chemical resistance was tested with HCl and NaOH. The ZnO nanopowder was packed with 100psi pressure in an empty C-18 column cavity. The column packing resolution was evaluated using a high performance liquid chromatographer (HPLC-Thermo Scientific Dionex UltiMate 3000); using a caffeine standard, the following parameters were established: solvent flow: 1.2mL/min, average column temperature: 40°C, running time: 10 minutes, mobile phase acetonitrile-water composition (9:1). These results validate the potential of ZnO nanopowder as a column packing material in HPLC technique.

  3. Surface Modification of Nanometre Silicon Carbide Powder with Polystyrene by Inductively Coupled Plasma

    Institute of Scientific and Technical Information of China (English)

    WEI Gang; MENG Yuedong; ZHONG Shaofeng; LIU Feng; JIANG Zhongqing; SHU Xingsheng; REN Zhaoxing; WANG Xiangke

    2008-01-01

    An investigation was made into polystyrene (PS) grafted onto nanometre sili-con carbide (SIC) particles. In our experiment, the grafting polymerization reaction was in-duced by a radio frequency (RF) inductively coupled plasma (ICP) treatment of the nanome-tre powder. FTIR (Fourier transform infrared spectrum) and XPS (X-ray photoelectron spec-troscopy) results reveal that PS is grafted onto the surface of silicon carbide powder. An analysis is presented on the effectiveness of this approach as a function of plasma operating variables including the plasma treating power, treating time, and grafting reaction temperature and time.

  4. Three-dimensional nanometre localization of nanoparticles to enhance super-resolution microscopy.

    Science.gov (United States)

    Bon, Pierre; Bourg, Nicolas; Lécart, Sandrine; Monneret, Serge; Fort, Emmanuel; Wenger, Jérôme; Lévêque-Fort, Sandrine

    2015-07-27

    Meeting the nanometre resolution promised by super-resolution microscopy techniques (pointillist: PALM, STORM, scanning: STED) requires stabilizing the sample drifts in real time during the whole acquisition process. Metal nanoparticles are excellent probes to track the lateral drifts as they provide crisp and photostable information. However, achieving nanometre axial super-localization is still a major challenge, as diffraction imposes large depths-of-fields. Here we demonstrate fast full three-dimensional nanometre super-localization of gold nanoparticles through simultaneous intensity and phase imaging with a wavefront-sensing camera based on quadriwave lateral shearing interferometry. We show how to combine the intensity and phase information to provide the key to the third axial dimension. Presently, we demonstrate even in the occurrence of large three-dimensional fluctuations of several microns, unprecedented sub-nanometre localization accuracies down to 0.7 nm in lateral and 2.7 nm in axial directions at 50 frames per second. We demonstrate that nanoscale stabilization greatly enhances the image quality and resolution in direct stochastic optical reconstruction microscopy imaging.

  5. Raster microdiffraction with synchrotron radiation of hydrated biopolymers with nanometre step-resolution: case study of starch granules

    Energy Technology Data Exchange (ETDEWEB)

    Riekel, C., E-mail: riekel@esrf.fr; Burghammer, M.; Davies, R. J.; Di Cola, E. [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex (France); König, C. [Paul Scherrer Institut, Bioenergy and Catalysis Laboratory, CH-5232 Villigen PSI (Switzerland); Lemke, H.T. [Centre for Molecular Movies, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen (Denmark); Putaux, J.-L. [Centre de Recherches sur les Macromolécules Végétales (CERMAV-CNRS), BP 53, F 38041 Grenoble Cedex 9 (France); Schöder, S. [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex (France)

    2010-11-01

    Radiation damage propagation was examined in starch granules by synchrotron radiation micro- and nano-diffraction techniques from cryo- to room temperatures. Careful dose limitation allowed raster-diffraction experiments with 500 nm step resolution to be performed. X-ray radiation damage propagation is explored for hydrated starch granules in order to reduce the step resolution in raster-microdiffraction experiments to the nanometre range. Radiation damage was induced by synchrotron radiation microbeams of 5, 1 and 0.3 µm size with ∼0.1 nm wavelength in B-type potato, Canna edulis and Phajus grandifolius starch granules. A total loss of crystallinity of granules immersed in water was found at a dose of ∼1.3 photons nm{sup −3}. The temperature dependence of radiation damage suggests that primary radiation damage prevails up to about 120 K while secondary radiation damage becomes effective at higher temperatures. Primary radiation damage remains confined to the beam track at 100 K. Propagation of radiation damage beyond the beam track at room temperature is assumed to be due to reactive species generated principally by water radiolysis induced by photoelectrons. By careful dose selection during data collection, raster scans with 500 nm step-resolution could be performed for granules immersed in water.

  6. Raster microdiffraction with synchrotron radiation of hydrated biopolymers with nanometre step-resolution: case study of starch granules.

    Science.gov (United States)

    Riekel, C; Burghammer, M; Davies, R J; Di Cola, E; König, C; Lemke, H T; Putaux, J L; Schöder, S

    2010-11-01

    X-ray radiation damage propagation is explored for hydrated starch granules in order to reduce the step resolution in raster-microdiffraction experiments to the nanometre range. Radiation damage was induced by synchrotron radiation microbeams of 5, 1 and 0.3 µm size with ∼0.1 nm wavelength in B-type potato, Canna edulis and Phajus grandifolius starch granules. A total loss of crystallinity of granules immersed in water was found at a dose of ∼1.3 photons nm(-3). The temperature dependence of radiation damage suggests that primary radiation damage prevails up to about 120 K while secondary radiation damage becomes effective at higher temperatures. Primary radiation damage remains confined to the beam track at 100 K. Propagation of radiation damage beyond the beam track at room temperature is assumed to be due to reactive species generated principally by water radiolysis induced by photoelectrons. By careful dose selection during data collection, raster scans with 500 nm step-resolution could be performed for granules immersed in water.

  7. Raster microdiffraction with synchrotron radiation of hydrated biopolymers with nanometre step-resolution: case study of starch granules

    Science.gov (United States)

    Riekel, C.; Burghammer, M.; Davies, R. J.; Di Cola, E.; König, C.; Lemke, H.T.; Putaux, J.-L.; Schöder, S.

    2010-01-01

    X-ray radiation damage propagation is explored for hydrated starch granules in order to reduce the step resolution in raster-microdiffraction experiments to the nanometre range. Radiation damage was induced by synchrotron radiation microbeams of 5, 1 and 0.3 µm size with ∼0.1 nm wavelength in B-type potato, Canna edulis and Phajus grandifolius starch granules. A total loss of crystallinity of granules immersed in water was found at a dose of ∼1.3 photons nm−3. The temperature dependence of radiation damage suggests that primary radiation damage prevails up to about 120 K while secondary radiation damage becomes effective at higher temperatures. Primary radiation damage remains confined to the beam track at 100 K. Propagation of radiation damage beyond the beam track at room temperature is assumed to be due to reactive species generated principally by water radiolysis induced by photoelectrons. By careful dose selection during data collection, raster scans with 500 nm step-resolution could be performed for granules immersed in water. PMID:20975219

  8. Study of ac hopping conductivity on one-dimensional nanometre systems

    Institute of Scientific and Technical Information of China (English)

    徐慧; 宋祎璞

    2002-01-01

    In this paper, we establish a one-dimensional random nanocrystalline chain model, we derive a new formula of ac electron-phonon-field conductance for electron tunnelling transfer in one-dimensional nanometre systems. By calculating the ac conductivity, the relationship between the electric field, temperature and conductivity is analysed, and the effect of crystalline grain size and distortion of interfacial atoms on the ac conductance is discussed. A characteristic of negative differential dependence of resistance and temperature in the low-temperature region for a nanometre system is found. The ac conductivity increases linearly with rising frequency of the electric field, and it tends to increase as the crystalline grain size increases and to decrease as the distorted degree of interfacial atoms increases.

  9. What holds paper together: Nanometre scale exploration of bonding between paper fibres

    Science.gov (United States)

    Schmied, Franz J.; Teichert, Christian; Kappel, Lisbeth; Hirn, Ulrich; Bauer, Wolfgang; Schennach, Robert

    2013-01-01

    Paper, a man-made material that has been used for hundreds of years, is a network of natural cellulosic fibres. To a large extent, it is the strength of bonding between these individual fibres that controls the strength of paper. Using atomic force microscopy, we explore here the mechanical properties of individual fibre-fibre bonds on the nanometre scale. A single fibre-fibre bond is loaded with a calibrated cantilever statically and dynamically until the bond breaks. Besides the calculation of the total energy input, time dependent processes such as creep and relaxation are studied. Through the nanometre scale investigation of the formerly bonded area, we show that fibrils or fibril bundles play a crucial role in fibre-fibre bonding because they act as bridging elements. With this knowledge, new fabrication routes can be deduced to increase the strength of an ancient product that is in fact an overlooked high-tech material. PMID:23969946

  10. Sub-nanometre control of the coherent interaction between a single molecule and a plasmonic nanocavity

    Science.gov (United States)

    Zhang, Yao; Meng, Qiu-Shi; Zhang, Li; Luo, Yang; Yu, Yun-Jie; Yang, Ben; Zhang, Yang; Esteban, Ruben; Aizpurua, Javier; Luo, Yi; Yang, Jin-Long; Dong, Zhen-Chao; Hou, J. G.

    2017-05-01

    The coherent interaction between quantum emitters and photonic modes in cavities underlies many of the current strategies aiming at generating and controlling photonic quantum states. A plasmonic nanocavity provides a powerful solution for reducing the effective mode volumes down to nanometre scale, but spatial control at the atomic scale of the coupling with a single molecular emitter is challenging. Here we demonstrate sub-nanometre spatial control over the coherent coupling between a single molecule and a plasmonic nanocavity in close proximity by monitoring the evolution of Fano lineshapes and photonic Lamb shifts in tunnelling electron-induced luminescence spectra. The evolution of the Fano dips allows the determination of the effective interaction distance of ~1 nm, coupling strengths reaching ~15 meV and a giant self-interaction induced photonic Lamb shift of up to ~3 meV. These results open new pathways to control quantum interference and field-matter interaction at the nanoscale.

  11. Stabilization and positioning of CLIC quadrupole magnets with sub-nanometre resolution

    CERN Document Server

    Janssens, S; Collette, C; Esposito, M; Fernandez Carmona, P; Guinchard, M; Hauviller, C; Kuzmin, A; Leuxe, R; Moron Ballester, R

    2011-01-01

    To reach the required luminosity at the CLIC interaction point, about 2000 quadrupoles along each linear collider are needed to obtain a vertical beam size of 1 nm at the interaction point. Active mechanical stabilization is required to limit the vibrations of the magnetic axis to the nanometre level in a frequency range from 1 to 100 Hz. The approach of a stiff actuator support was chosen to isolate from ground motion and technical vibrations acting directly on the quadrupoles. The actuators can also reposition the quadrupoles between beam pulses with nanometre resolution. A first conceptual design of the active stabilization and nano positioning based on the stiff support and seismometers was validated in models and experimentally demonstrated on test benches. Lessons learnt from the test benches and information from integrated luminosity simulations using measured stabilization transfer functions lead to improvements of the actuating support, the sensors used and the system controller. The controller elect...

  12. High-Spatial-Resolution Monitoring of Strong Magnetic Field using Rb vapor Nanometric-Thin Cell

    CERN Document Server

    Hakhumyan, G; Pashayan-Leroy, Y; Sarkisyan, D; Auzinsh, M

    2011-01-01

    We have implemented the so-called $\\lambda$-Zeeman technique (LZT) to investigate individual hyperfine transitions between Zeeman sublevels of the Rb atoms in a strong external magnetic field $B$ in the range of $2500 - 5000$ G (recently it was established that LZT is very convenient for the range of $10 - 2500$ G). Atoms are confined in a nanometric thin cell (NTC) with the thickness $L = \\lambda$, where $\\lambda$ is the resonant wavelength 794 nm for Rb $D_1$ line. Narrow velocity selective optical pumping (VSOP) resonances in the transmission spectrum of the NTC are split into several components in a magnetic field with the frequency positions and transition probabilities depending on the $B$-field. Possible applications are described, such as magnetometers with nanometric local spatial resolution and tunable atomic frequency references.

  13. High-spatial-resolution monitoring of strong magnetic field using Rb vapor nanometric-thin cell

    Science.gov (United States)

    Hakhumyan, G.; Leroy, C.; Pashayan-Leroy, Y.; Sarkisyan, D.; Auzinsh, M.

    2011-08-01

    We have implemented the so-called λ-Zeeman technique (LZT) to investigate individual hyperfine transitions between Zeeman sublevels of the Rb atoms in a strong external magnetic field B in the range of 2500 - 5000 G (recently it was established that LZT is very convenient for the range of 10 - 2500 G). Atoms are confined in a nanometric thin cell (NTC) with the thickness L = λ, where λ is the resonant wavelength 794 nm for Rb D 1 line. Narrow velocity selective optical pumping (VSOP) resonances in the transmission spectrum of the NTC are split into several components in a magnetic field with the frequency positions and transition probabilities depending on the B-field. Possible applications are described, such as magnetometers with nanometric local spatial resolution and tunable atomic frequency references.

  14. Influence of Thickness on Field Emission Characteristics of Nanometre Boron Nitride Thin Films

    Institute of Scientific and Technical Information of China (English)

    顾广瑞; 李英爱; 陶艳春; 何志; 李俊杰; 殷红; 李卫青; 赵永年

    2003-01-01

    Nanometre boron nitride (BN) thin films with various thickness (54-135 nm) were prepared on Si(100) by rf magnetic sputtering physical vapour deposition. The field emission characteristics of the BN thin films were measured in an ultrahigh vacuum system. A threshold electric field of 11 V/μm and the highest emission current density of 240 μA/cm2 at an electric field of 23 V/μm were obtained for the about 54-nm-thick BN film. The threshold electric field increases with increasing the thickness in the nanometre range. The Fowler-Nordheim plots show that electrons were emitted from BN to vacuum by tunnelling through the potential barrier at the surface of BN thin films.

  15. Status of a study of stabilization and fine positioning of CLIC quadrupoles to the nanometre level

    CERN Document Server

    Artoos, K; Esposito, M; Fernandez Carmona, P; Guinchard, M; Hauviller, C; Janssens, S; Kuzmin, A; Leuxe, R; Moron Ballester, R

    2011-01-01

    Mechanical stability to the nanometre and below is required for the Compact Linear Collider (CLIC) quadrupoles to frequencies as low as 1 Hz. An active stabilization and positioning system based on very stiff piezo electric actuators and inertial reference masses is under study for the Main Beam Quadrupoles (MBQ). The stiff support was selected for robustness against direct forces and for the option of incrementally repositioning the magnet with nanometre resolution. The technical feasibility was demonstrated by a representative test mass being stabilized and repositioned to the required level in the vertical and lateral direction. Technical issues were identified and the development programme of the support, sensors, and controller was continued to increase the performance, integrate the system in the overall controller, adapt to the accelerator environment, and reduce costs. The improvements are implemented in models, test benches, and design of the first stabilized prototype CLIC magnet. The characterizati...

  16. Fabrication and characterization of nanometric SiOx/SiOy multilayer structures obtained by LPCVD

    Energy Technology Data Exchange (ETDEWEB)

    Román-López, S.; Aceves-Mijares, M.; Pedraza-Chávez, J. [National Institute for Astrophysics, Optics and Electronics, L. Erro 1, Tonatzintla Puebla (Mexico); Carrillo-López, J. [Center of Res. on Semiconductors Dev. BUAP, Av. San Claudio y 14 Sur CU, Puebla Puebla (Mexico)

    2014-05-15

    This work presents the fabrication of nanometric multilayer structures and their characterization by Atomic Force Microscopy, Photoluminescence and Fourier Transform Infra Red spectroscopy. The structures were deposited by Low Pressure Chemical Vapor Deposition (LPCVD). Three types of multilayer structure were fabricated. After the deposition some samples were annealed in N{sub 2} ambient for three hours. It was found that the structures keep the characteristics of each layer.

  17. Characterization of Nanometric-Sized Carbides Formed During Tempering of Carbide-Steel Cermets

    OpenAIRE

    Matus K.; Pawlyta M.; Matula G.; Gołombek K.

    2016-01-01

    The aim of this article of this paper is to present issues related to characterization of nanometric-sized carbides, nitrides and/or carbonitrides formed during tempering of carbide-steel cermets. Closer examination of those materials is important because of hardness growth of carbide-steel cermet after tempering. The results obtained during research show that the upswing of hardness is significantly higher than for high-speed steels. Another interesting fact is the displacement of secondary ...

  18. Self-Assembly of Gold Nanoparticles on Nanometre-Patterned Surface

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong-Jun; YANG Jing-Hai; LI Wei; ZHANG Yu; XU Ling; XU Jun; HUANG Xin-Fan; CHEN Kun-Ji

    2005-01-01

    @@ The self-assembly processes of gold nanoparticles on nanometre-step-patterned Si surface and polished Si surface are investigated by the convective self-assembly method. The convective self-assembly method is used to deposit the colloids dispersed in benzene onto the substrates. The SEM results show that the configurations of the gold arrays depend on the surface morphology of the substrates. On the nanometre-step-patterned Si surface, the nanoparticles self assemble into parallel lines, and the distance between the neighbouring lines is around 35nm.On the polished Si surface the nanoparticles form compact domains. In each domain the particles are closepacked in a two-dimensional hexagonal superlattice and are separated by uniform distances. The analysis shows that on the nanometre-step-patterned Si surface, the steps play critical roles in the self-assembly process of gold nanoparticles. The capillary force from the steps drives the particles to lines along the steps. Therefore, the particles tend to self-assemble into one-dimensional line structures when the solvent evaporates. For the polished Si substrate there isa little difference that the particles form two-dimensional hexagonal superlattices without the directional confinement.

  19. Study of radiative heat transfer in Ångström- and nanometre-sized gaps

    Science.gov (United States)

    Cui, Longji; Jeong, Wonho; Fernández-Hurtado, Víctor; Feist, Johannes; García-Vidal, Francisco J.; Cuevas, Juan Carlos; Meyhofer, Edgar; Reddy, Pramod

    2017-02-01

    Radiative heat transfer in Ångström- and nanometre-sized gaps is of great interest because of both its technological importance and open questions regarding the physics of energy transfer in this regime. Here we report studies of radiative heat transfer in few Å to 5 nm gap sizes, performed under ultrahigh vacuum conditions between a Au-coated probe featuring embedded nanoscale thermocouples and a heated planar Au substrate that were both subjected to various surface-cleaning procedures. By drawing on the apparent tunnelling barrier height as a signature of cleanliness, we found that upon systematically cleaning via a plasma or locally pushing the tip into the substrate by a few nanometres, the observed radiative conductances decreased from unexpectedly large values to extremely small ones--below the detection limit of our probe--as expected from our computational results. Our results show that it is possible to avoid the confounding effects of surface contamination and systematically study thermal radiation in Ångström- and nanometre-sized gaps.

  20. Rotura em "alça de balde" simultânea dos meniscos no mesmo joelho Simultaneous "bucket-handle" tear of both menisci on the same knee

    Directory of Open Access Journals (Sweden)

    Andre Francisco Gomes

    2009-01-01

    Full Text Available Rotura em "alça de balde" de ambos os meniscos do mesmo joelho é um fenômeno raro. Apresentamos o caso de um paciente em que a ressonância magnética demonstrou rotura em "alça de balde" dos meniscos medial e lateral do mesmo joelho, associada a rotura do ligamento cruzado anterior, confirmado por videoartroscopia. A ressonância magnética demonstra sinais que permitem o diagnóstico preciso.Simultaneous "bucket-handle" tear of menisci on the same knee is a rare phenomenon. We describe a case of a bucket-handle tear of menisci and tear of anterior cruciate ligament of the same knee showed on magnetic resonance imaging and confirmed by arthroscopy. The magnetic resonance imaging can provide accurate diagnosis of this type of injury.

  1. Ionization-cluster distributions of alpha-particles in nanometric volumes of propane: measurement and calculation.

    Science.gov (United States)

    De Nardo, L; Colautti, P; Conte, V; Baek, W Y; Grosswendt, B; Tornielli, G

    2002-12-01

    The probability of the formation of ionization clusters by primary alpha-particles at 5.4 MeV in nanometric volumes of propane was studied experimentally and by Monte Carlo simulation, as a function of the distance between the center line of the particle beam and the center of the target volume. The volumes were of cylindrical shape, 3.7 mm in diameter and height. As the investigations were performed at gas pressures of 300 Pa and 350 Pa, the dimensions of the target volume were equivalent to 20.6 nm or 24.0 nm in a material of density 1.0 g/cm(3). The dependence of ionization-cluster formation on distance was studied up to values equivalent to about 70 nm. To validate the measurements, a Monte Carlo model was developed which allows the experimental arrangement and the interactions of alpha-particles and secondary electrons in the counter gas to be properly simulated. This model is supplemented by a mathematical formulation of cluster size formation in nanometric targets. The main results of our study are (i) that the mean ionization-cluster size in the delta-electron cloud of an alpha-particle track segment, decreases as a function of the distance between the center line of the alpha-particle beam and the center of the sensitive target volume to the power of 2.6, and (ii) that the mean cluster size in critical volumes and the relative variance of mean cluster size due to delta-electrons are invariant at distances greater than about 20 nm. We could imagine that the ionization-cluster formation in nanometric volumes might in future provide the physical basis for a redefinition of radiation quality.

  2. Tribological Properties of Nanometric Atomic Layer Depositions Applied on AISI 420 Stainless Steel

    Directory of Open Access Journals (Sweden)

    E. Marin

    2013-09-01

    Full Text Available Atomic Layer Deposition ( ALD is a modern technique that Allows to deposit nanometric, conformal coatings on almost any kind of substrates, from plastics to ceramic, metals or even composites. ALD coatings are not dependent on the morphology of the substrate and are only regulated by the composition of the precursors, the chamber temperature and the number of cycles. In this work, mono- and bi -layer nanometric, protective low-temperature ALD Coatings, based on Al2O3 and TiO2 were applied on AISI 420 Stainless Steel in orderto enhance its relatively low corrosion resistance in chloride containing environments. Tribological testing were also performed on the ALD coated AISI 420 in order to evaluate the wear and scratch resistance of these nanometric layers and thus evaluate their durability. Scratch tests were performed using a standard Rockwell C indenter, under a variable load condition, in order to evaluate the critical loading condition for each coating. Wear testing were performed using a stainless steel counterpart, in ball-on-discconfiguration, in order to measure the friction coefficient and wear to confront the resistance. All scratch tests scars and wear tracks were then observed by means of Scanning Electron Microscopy (SEM in order to understand the wear mechanisms that occurred on the sample surfaces. Corrosion testing, performed under immersion in 0.2 M NaCl solutions, clearly showed that the ALD coatings have a strong effect in protecting the Stainless Steel Substrate against corrosion, reducing the corrosion current density by two orders of magnitude.Tribological The preliminary results showed that ALD depositions obtained at low Temperatures have a brittle behavior caused by the amorphous nature of their structure, and thus undergo delamination phenomena during Scratch Testing at relatively low applied loads. During ball-on-disc testing, the coatings were removed from the substrate, in particular for monolayer ALD configurations

  3. Catalyst FeNi supported on nanometric mezoporous oxide for PEMFC applications

    DEFF Research Database (Denmark)

    Serban, E. C.; Banu, N.; Marinescu, A. C.;

    2011-01-01

    Proton exchange membrane fuel cells (PEMFC) are studied intensive for hydrogen - oxygen couple conversion into electrical power via electro-chemical process. Electrocatalyst performances (defined by specific area and catalytic activity) represent a key point for hydrogen oxidation - anode reaction....... Pt is a representative catalyst in these applications, but it has a few drawbacks, such as CO poisoning. The present work is focused on the study of catalytic activity of nanometric Iron (Fe) - Nickel (Ni) couple deposited on TiO(2) / SiO(2) materials....

  4. Pulsed electron-electron double resonance (PELDOR) as EPR spectroscopy in nanometre range

    Energy Technology Data Exchange (ETDEWEB)

    Tsvetkov, Yu D; Milov, A D; Maryasov, A G [Institute of Chemical Kinetics and Combustion, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2008-06-30

    The results of development of pulsed electron-electron double resonance (PELDOR) method and its applications in structural studies are generalised and described systematically. The foundations of the theory of the method are outlined, some methodological features and applications are considered, in particular, determination of the distances between spin labels in the nanometre range for iminoxyl biradicals, spin-labelled biomacromolecules, radical ion pairs and peptide-membrane complexes. The attention is focussed on radical systems that form upon self-assembly of nanosized complexes (in particular, peptide complexes), spatial effects, and radical pairs in photolysis and photosynthesis. The position of PELDOR among other structural EPR techniques is analysed.

  5. InAs/GaAs quantum dots morphology: Nanometric scale HAADF simulations

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, D., E-mail: daniel.araujo@uca.e [Departamento de Ciencia de los Materiales e IM y QI, Universidad de Cadiz, 11510 Puerto Real (Spain); El Bouayadi, R. [Faculte Pluridisciplinaire de Nador, B.P. 300, Selouane 62700 (Morocco); Gutierrez, M.; Pastore, C.E. [Departamento de Ciencia de los Materiales e IM y QI, Universidad de Cadiz, 11510 Puerto Real (Spain); Hopkinson, M. [Department of Electronic and Electrical Engineering, University of Sheffield, S1 3JD Sheffield (United Kingdom)

    2009-11-25

    A quantitative methodology of In distribution in nominal InAs/GaAs individual quantum dot (QD) is presented. Numerical simulations, using multislice-based approach, allow predicting high angle annular dark field (HAADF or Z-contrast) micrograph contrasts working in scanning transmission electron microscopy (STEM) mode. Even the method is adapted for nanometric scale; it is shown that its high sensitivity can reveal In-segregation in QD. The here observed samples show In diffusion below the wetting layer giving an elliptical-like shape of the observed QD.

  6. Observing Nanometre Scale Particles with Light Scattering for Manipulation Using Optical Tweezers

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jin-Hua; Qu Lian-Jie; Yao Kun; ZHONG Min-Cheng; LI Yin-Mei

    2008-01-01

    Nanometre-scale particles can be manipulated using optical tweezers,but cannot be directly observed.We Drasent a simple method that nanoparticles can be directly observed using optical tweezers combined with dark field microscopy.A laser beam perpendicular to a tightly focused laser beam for trap illuminates specimen and does not enter objective,nanoparticles in focal plane all can be directly observed in dark field because of light scattering.It is implemented that the polystyrene beads of diameter 100nm can be directly observed and trapped.

  7. Near-Field Fluorescence and Topography Characterization of a Single Nanometre Fluorophore by Apertureless Tip-Enhanced Scanning Near-Field Microscopy

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-Bin; WANG Jia; XU Ji-Ying; WANG Rui; TIAN Qian; YU Jian-Yuan

    2007-01-01

    Tip-enhanced near-field fluorescence and topography characterization of a single nanometre fluorophore is conducted by using an apertureless scanning near-field microscopy system. A fluorophore with size 80nm is mapped with a spatial resolution of 10nm. The corresponding near-field fluorescence data shows significant signal enhancement due to the apertureless tip-enhanced effect. With the nanometre spatial resolution capability and nanometre local tip-enhanced effect, the apertureless tip-enhanced scanning near-field microscopy may be further used to characterize a single molecule by realizing the local near-field spectrum assignment corresponding to topography at nanometre scale.

  8. Engineering a Biocompatible Scaffold with Either Micrometre or Nanometre Scale Surface Topography for Promoting Protein Adsorption and Cellular Response

    Directory of Open Access Journals (Sweden)

    Xuan Le

    2013-01-01

    Full Text Available Surface topographical features on biomaterials, both at the submicrometre and nanometre scales, are known to influence the physicochemical interactions between biological processes involving proteins and cells. The nanometre-structured surface features tend to resemble the extracellular matrix, the natural environment in which cells live, communicate, and work together. It is believed that by engineering a well-defined nanometre scale surface topography, it should be possible to induce appropriate surface signals that can be used to manipulate cell function in a similar manner to the extracellular matrix. Therefore, there is a need to investigate, understand, and ultimately have the ability to produce tailor-made nanometre scale surface topographies with suitable surface chemistry to promote favourable biological interactions similar to those of the extracellular matrix. Recent advances in nanoscience and nanotechnology have produced many new nanomaterials and numerous manufacturing techniques that have the potential to significantly improve several fields such as biological sensing, cell culture technology, surgical implants, and medical devices. For these fields to progress, there is a definite need to develop a detailed understanding of the interaction between biological systems and fabricated surface structures at both the micrometre and nanometre scales.

  9. Efficient perovskite light-emitting diodes featuring nanometre-sized crystallites

    Science.gov (United States)

    Xiao, Zhengguo; Kerner, Ross A.; Zhao, Lianfeng; Tran, Nhu L.; Lee, Kyung Min; Koh, Tae-Wook; Scholes, Gregory D.; Rand, Barry P.

    2017-01-01

    Organic-inorganic hybrid perovskite materials are emerging as highly attractive semiconductors for use in optoelectronics. In addition to their use in photovoltaics, perovskites are promising for realizing light-emitting diodes (LEDs) due to their high colour purity, low non-radiative recombination rates and tunable bandgap. Here, we report highly efficient perovskite LEDs enabled through the formation of self-assembled, nanometre-sized crystallites. Large-group ammonium halides added to the perovskite precursor solution act as a surfactant that dramatically constrains the growth of 3D perovskite grains during film forming, producing crystallites with dimensions as small as 10 nm and film roughness of less than 1 nm. Coating these nanometre-sized perovskite grains with longer-chain organic cations yields highly efficient emitters, resulting in LEDs that operate with external quantum efficiencies of 10.4% for the methylammonium lead iodide system and 9.3% for the methylammonium lead bromide system, with significantly improved shelf and operational stability.

  10. Synthesis of nanometric refractory alloys powders in the Mo−Nb−W system

    Energy Technology Data Exchange (ETDEWEB)

    Kentheswaran, Vasuki; Dine, Sarah [Université Paris 13, Sorbonne Paris Cité, LSPM, CNRS UPR 3407, 99 avenue Jean-Baptiste Clément, 93430 Villetaneuse (France); Vrel, Dominique, E-mail: dominique.vrel@lspm.cnrs.fr [Université Paris 13, Sorbonne Paris Cité, LSPM, CNRS UPR 3407, 99 avenue Jean-Baptiste Clément, 93430 Villetaneuse (France); Couzinié, Jean-Philippe [ICMPE, Université Paris Est, UMR 7182, CNRS, UPEC, 94320 Thiais (France); Dirras, Guy [Université Paris 13, Sorbonne Paris Cité, LSPM, CNRS UPR 3407, 99 avenue Jean-Baptiste Clément, 93430 Villetaneuse (France)

    2016-09-15

    Nanometric powders of stoichiometric compositions in the Mo−Nb, Mo−W, Nb−W binary systems and in the Mo−Nb−W ternary system were produced by highly exothermic reactions using Mechanically Induced Chemical Reaction (MICR), Self-propagating High-temperature Synthesis (SHS) and Mechanically Activated Self-propagating High-temperature Synthesis (MASHS), through the reduction of their oxides by magnesium, with sodium chloride used as a reaction moderator. Results demonstrate the possibility to obtain high purity nanostructured products in the 20–150 nm range, with an average equivalent diameter, from specific surface measurements, of 44 nm. However, in Nb containing samples, the main BCC phase always comes with one or more secondary phases, for which further developments are necessary in order either to avoid its formation or to find a way to eliminate it. - Highlights: • Nanometric refractory powders in the Mo−Nb−W system have been synthesized. • Three high-energy processes (SHS, MASHS, milling) have been compared. • Process parameters can be adjusted to yield homogeneous alloys in the nanoscale.

  11. Supercritical CO2 generation of nanometric structure from Ocimum basilicum mucilage prepared for pharmaceutical applications.

    Science.gov (United States)

    Akbari, Iman; Ghoreishi, Seyyed M; Habibi, Neda

    2015-04-01

    Plant-derived polymers are widely used in the pharmaceutical industry due to their emollient, lack of toxicity, and irritating nature and low cost. In this work, basil seed mucilage was dried using supercritical carbon dioxide phase inversion technique to form a nanometric structure. The obtained polymeric structures were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) method, and Fourier transform infrared spectroscopy (FTIR) and compared with the oven-derived sample group. It was demonstrated that the product morphology could be controlled by altering the composition of methanol which functioned as the co-solvent in the nonsolvent stream. The most homogeneous product (60-nm mean pore size diameter, 78 m(2)/g BET surface area with no agglomeration) was obtained with 2.5% methanol. The FTIR data showed that the presence of hydroxyl and carboxyl groups suggested the bioadhesive property of basil seed mucilage was good and many active pharmaceutical compounds might be loaded to the resultant nanometric structure to enhance drug release. Furthermore, the FTIR analyses indicated that the nature of the final product did not change during the supercritical drying procedure.

  12. Optical properties of nanometre AgI silica composite synthesized by a simple quenching method

    Science.gov (United States)

    He, Haiping; Wang, Yuxia; Zou, Youming

    2003-07-01

    Optical absorption and room temperature photoluminescence (PL) properties of nanometre AgI-silica composite synthesized by a simple heating-quenching method were investigated. The absorption of quenched AgI-silica was enhanced markedly. Three absorption bands at 440 (2.8 eV), 260 (4.8 eV) and 220 nm (5.6 eV) were observed. The excitonic absorption of AgI showed a red shift of ~0.11 eV, in contrast to the usually observed blue shift in AgI nanocrystals. Besides two UV emissions from a non-bridging hole centre and E' centre defects formed in silica, the composite exhibited two PL emissions at 2.62 and 2.40 eV. The 2.62 eV PL was ascribed to donor-acceptor recombination of AgI, while the 2.40 eV one may correlate with energy levels induced by the interaction between silica and AgI. The role of silica in improving the PL for nanometre AgI is discussed.

  13. Sensing nanometric displacement of a micro-/nano-fiber induced by optical forces by use of white light interferometry

    Science.gov (United States)

    Qiu, Weiqia; Huang, Hankai; Yu, Jianhui; Dong, Huazhuo; Chen, Zhe; Lu, Huihui

    2015-07-01

    Sensing the nanometric displacement of a micro-/nano-fiber induced by optical forces is a key technology to study optical forces and optical momentum. When the gap between a micro-/nano-fiber and glass substrate becomes down to micrometer scale or less, a white light interference was observed. The gap changes when optical force arising from the propagating pump light along the micro-/nano-fiber causes a transversal nanometric displacement of a micro-/nanofiber, resulting in movement of the interferometric fringes. Therefore this movement of the interferometric fringes can be used to sense the nanometric displacement of the micro-/nano-fiber induced by optical forces. Experimental results show that the resolutions of this method can reach 7.27nm/pixel for tilted angle 0.8o between the micro-/nano-fiber and substrate. It is concluded that the white light interferometry method is suitable for measuring the weak optical force.

  14. Laser generation of elliptical nanometre and sub-nanometre bump arrays on NiP/Al data storage disks and their effect on stiction performance.

    Science.gov (United States)

    Pena, A A; Wang, Z B; Zhang, J; Wu, N E; Li, L

    2011-09-07

    Elliptical nano-bumps on nickel-phosphorus coated aluminium (NiP/Al) hard disks were fabricated by a laser texturing system (maximum power 8 W, maximum frequency 300 kHz). By carefully selecting the level of laser power attenuation and defocus offset distance, bump height can be controlled below 6 nm and down to the sub-nanometre scale. This type of laser-induced texture (elliptical shape) on a disk surface is expected to provide better control of the stiction force along with the smallest separation distance between the head slider and the disk. Quantitative modelling based on the classical Hertzian theory for elliptic contacts has been carried out with the purpose of predicting the stiction behaviour of the presented elliptical shaped sub-10 nm bumps. It has been found that an elliptical shape not only reduces the overall stiction performance of the laser texturing zone (LZT) compared to the conventional circular shape but also extends the occurrence of the 'stiction wall' towards the sub-10 nm regime for ultra-low-glide applications.

  15. Neutron reflectometry yields distance-dependent structures of nanometric polymer brushes interacting across water.

    Science.gov (United States)

    Rodriguez-Loureiro, Ignacio; Scoppola, Ernesto; Bertinetti, Luca; Barbetta, Aurelio; Fragneto, Giovanna; Schneck, Emanuel

    2017-08-30

    The interaction between surfaces displaying end-grafted hydrophilic polymer brushes plays important roles in biology and in many wet-technological applications. In this context, the conformation of the brushes upon their mutual approach is crucial, because it affects interaction forces and the brushes' shear-tribological properties. While this aspect has been addressed by theory, experimental data on polymer conformations under confinement are difficult to obtain. Here, we study interacting planar brushes of hydrophilic polymers with defined length and grafting density. Via ellipsometry and neutron reflectometry we obtain pressure-distance curves and determine distance-dependent polymer conformations in terms of brush compression and reciprocative interpenetration. While the pressure-distance curves are satisfactorily described by the Alexander-de-Gennes model, the pronounced brush interpenetration as seen by neutron reflectometry motivates detailed simulation-based studies capable of treating brush interpenetration on a quantitative level.

  16. The morphology of cometary dust: Subunit size distributions down to tens of nanometres

    Science.gov (United States)

    Mannel, Thurid; Bentley, Mark; Boakes, Peter; Jeszenszky, Harald; Levasseur-Regourd, Anny-Chantal; Schmied, Roland; Torkar, Klaus

    2017-04-01

    The Rosetta orbiter carried a dedicated analysis suite for cometary dust. One of the key instruments was MIDAS (Micro-Imaging Dust Analysis System), an atomic force microscope that scanned the surfaces of hundreds of (sub-)micrometre particles in 3D with resolutions down to nanometres. This provided the opportunity to study the morphology of the smallest cometary dust; initial investigation revealed that the particles are agglomerates of smaller subunits [1] with different structural properties [2]. To understand the (surface-) structure of the dust particles and the origin of their smallest building blocks, a number of particles were investigated in detail and the size distribution of their subunits determined [3]. Here we discuss the subunit size distributions ranging from tens of nanometres to a few micrometres. The differences between the subunit size distributions for particles collected pre-perihelion, close to perihelion, and during a huge outburst are examined, as well as the dependence of subunit size on particle size. A case where a particle was fragmented in consecutive scans allows a direct comparison of fragment and subunit size distributions. Finally, the small end of the subunit size distribution is investigated: the smallest determined sizes will be reviewed in the context of other cometary missions, interplanetary dust particles believed to originate from comets, and remote observations. It will be discussed if the smallest subunits can be interpreted as fundamental building blocks of our early Solar System and if their origin was in our protoplanetary disc or the interstellar material. References: [1] M.S. Bentley, R. Schmied, T. Mannel et al., Aggregate dust particles at comet 67P/Chruyumov-Gerasimenko, Nature, 537, 2016. doi:10.1038/nature19091 [2] T. Mannel, M.S. Bentley, R. Schmied et al., Fractal cometary dust - a window into the early Solar system, MNRAS, 462, 2016. doi:10.1093/mnras/stw2898 [3] R. Schmied, T. Mannel, H. Jeszenszky, M

  17. Cell sheet engineering: solvent effect on nanometric grafting of poly-N-isopropylacrylamide onto polystyrene substrate under ultraviolet radiation

    Directory of Open Access Journals (Sweden)

    Esmaeil Biazar

    2011-02-01

    Full Text Available Esmaeil Biazar1, MT Khorasani2, M Daliri31Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran; 2Biomaterial Department, Iran Polymer and Petrochemical Institute, Tehran, Iran; 3National Research Center for Genetic Engineering and Biotechnology, Tehran, IranBackground: The best solvent type and ratio for grafting of poly-n-isopropylacrylamide (PNIPAAm on the surface of polystyrene is obtained under ultraviolet radiation. In this study, the effects of solvents, such as water, methanol, and their combinations, under ultraviolet radiation were investigated successfully.Method and results: Attenuated total reflection Fourier transform infrared analysis showed the existence of the graft PNIPAAm on the substrate for all samples resolved in solvents. The best solvent ratio and NIPAAm concentration for grafting was obtained with 40% NIPAAm concentrations resolved in a solvent of 9:1 (v/v water/methanol (120%. Scanning electron microscopic and atomic force microscopic images clearly showed that a 10% increase of methanol to water would increase the amount of grafting. Surface topography and graft thickness in atomic force microscopic images of the grafted samples showed that the thickness of these grafts was about 600 nm. The drop water contact angles of the best grafted sample at 37°C and 4°C were 43.3° and 60.4°, respectively, which demonstrated the hydrophilicity and hydrophobicity of the grafted surfaces. Differential scanning calorimetric analysis also revealed the low critical solution temperature of the grafted sample to be 32°C. Thermoresponsive polymers were grafted to dishes covalently, which allowed epithelial cells to attach and proliferate at 37°C. The cells were also detached spontaneously without using enzymes when the temperature dropped below 4°C.Conclusion: MTT analysis also showed good viability of cells on the grafted samples, suggesting that this type of grafted material had

  18. Nano-metric Dust Particles as a Hardly Detectable Component of the Interplanetary Dust Cloud

    Indian Academy of Sciences (India)

    I. Simonia; Sh. Nabiyev

    2015-09-01

    The present work introduces the hypothesis of existence of a hardly detectable component of the interplanetary dust cloud and demonstrates that such a component is a dust formation consisting of the dust particles of nano-metric dimensions. This work describes the main physical properties of such a kind of nano-dust, and its possible chemical and mineralogical peculiarities proposes new explanations related to reddening of the dynamically cold transneptunian objects on account of scattering their light by nano-dust of the hardly detectable component of the interplanetary dust cloud. We propose the relation for the coefficient of absorption by the nano-dust and provide results of the statistical analysis of the TNO color index–orbital inclinations. We also present a critical assessment of the proposed hypothesis.

  19. Failure of semiclassical models to describe resistivity of nanometric, polycrystalline tungsten films

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Dooho [Department of Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Korea Railroad Research Institute, 360-1 Woulam, Uiwang, Kyunggi 437-757 (Korea, Republic of); Liu, Xuan [Department of Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Schelling, Patrick K. [Advanced Materials Processing and Analysis Center and Department of Physics, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816 (United States); Coffey, Kevin R. [Department of Materials Science and Engineering, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816 (United States); Barmak, Katayun [Department of Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Department of Applied Physics and Applied Mathematics, Columbia University, 500 West 120th Street, New York, New York 10027 (United States)

    2014-03-14

    The impact of electron scattering at surfaces and grain boundaries in nanometric polycrystalline tungsten (W) films was studied. A series of polycrystalline W films ranging in thickness from 10 to 310 nm and lateral grain size from 74 to 133 nm were prepared on thermally oxidized Si. The Fuchs-Sondheimer surface-scattering model and Mayadas-Shatzkes grain-boundary scattering model were employed for quantitative analyses. Predictions from the theoretical models were found to deviate systematically from the experimental data. Possible reasons for the failure of the theoretical models to describe the experimental data are explored. Finally, a discussion of the crucial features lacking from existing models is presented, along with possible avenues for improving the models to result in better agreement with experimental data.

  20. Probing variations of the Rashba spin-orbit coupling at the nanometre scale

    Science.gov (United States)

    Bindel, Jan Raphael; Pezzotta, Mike; Ulrich, Jascha; Liebmann, Marcus; Sherman, Eugene Ya.; Morgenstern, Markus

    2016-10-01

    As the Rashba effect is an electrically tunable spin-orbit interaction, it could form the basis for a multitude of applications, such as spin filters, spin transistors and quantum computing using Majorana states in nanowires. Moreover, this interaction can determine the spin dephasing and antilocalization phenomena in two dimensions. However, the real space pattern of the Rashba parameter, which critically influences spin transistors using the spin-helix state and the otherwise forbidden electron backscattering in topologically protected channels, is difficult to probe. Here, we map this pattern down to nanometre length scales by measuring the spin splitting of the lowest Landau level using scanning tunnelling spectroscopy. We reveal strong fluctuations correlated with the local electrostatic potential for an InSb inversion layer with a large Rashba coefficient (~1 eV Å). This type of Rashba field mapping enables a more comprehensive understanding of its fluctuations, which might be decisive towards robust semiconductor-based spintronic devices.

  1. Effects of nanometric hydrophobic layer on performances of solar photovoltaic collectors

    Directory of Open Access Journals (Sweden)

    Andrei BUTUZA

    2014-11-01

    Full Text Available The study refers to the experimental investigation of solar photovoltaic collectors' behaviour when the glazed surface is treated with a nanometric layer of hydrophobic solution. The experiment was carried out on two photovoltaic collectors, of which one was considered as reference and the other one was coated with a commercial hydrophobic solution. It was studied the evolution of the following electrical parameters: current, voltage, power, efficiency and daily energy production. The voltage was almost unaffected, but for all the others parameters, important drop were recorded. The preliminary conclusion of the study is that the use of hydrophobic solutions, for the treatment of glazed surfaces of solar collectors is not recommended. This hypothesis needs supplementary investigations and measurements in the context of reduced available information concerning the optical properties of hydrophobic solutions.

  2. Size-Dependent Melting Behaviour of Nanometre-Sized Pb Particles Studied by Dynamic Mechanical Analysis

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-Min; FEI Guang-Tao; CUI Ping

    2006-01-01

    Nanometre-sized (hereafter nano-)Pb particles embedded in an Al matrix are prepared by ball milling.It is found that the size of nano-Pb particles was decreased with increasing milling time.The melting behaviour of nano-Pb particles embedded in the Al matrix is studied by means of dynamic mechanical analysis,and a single internal friction peak in the vicinity of Pb melting temperature is observed.The onset temperature of the peak moves to lower temperature with the decrease of particles size and the internal friction peak height is increased,which indicates a size-dependent melting behaviour of nano-Pb particles.It is suggested that the size-dependent melting behaviour is associated with surface melting.

  3. Novel Design of a Nano-metric Fast 4*4 Reversible unsigned Wallace Multiplier Circuit

    Directory of Open Access Journals (Sweden)

    Ehsan PourAliAkbar

    2015-12-01

    Full Text Available One of the most promising technologies in designing low-power circuits is reversible computing. It is used in nanotechnology, quantum computing, quantum dot cellular automata (QCA, DNA computing, optical computing and in CMOS low-power designs. Since reversible logic is subject to certain restrictions (e.g. fan-out and feedback are not allowed, traditional synthesis methods are not applicable and specific methods have been developed. In this paper, we offer a Wallace 4*4 reversible multiplier circuits which have faster speed and lower complexity in comparison with the other multiplier circuits. This circuit performs better, regarding to the number of gates, garbage outputs and constant inputs work better than the same circuits. In this paper, Peres gate is used as HA and HNG gate is used as FA. We offer the best method to multiply two 4 bit numbers. These Nano-metric circuits can be used in very complex systems.

  4. Alloying propagation in nanometric Ni/Al multilayers: A molecular dynamics study

    Science.gov (United States)

    Turlo, V.; Politano, O.; Baras, F.

    2017-02-01

    In nanometric metallic multilayers such as Ni/Al, the alloying reaction proceeds in the form of a propagating wave. We studied the different phase transformations involved in the reactive wave propagation by means of molecular dynamics. The focus was on a specific regime that involves melting of reactants, intermixing of reactants, and formation of an intermetallic compound. We found that the wave consists of two stages. The first front is associated with a dissolution process and propagates at several meters per second, while the second front is due to the crystallization of the final product and is slower, leading to a specific microstructure with alternated large grains of NiAl and liquid regions in the front propagation direction. Three main exothermic processes were identified, including grain coarsening. Their respective contributions were evaluated. We developed a new texture analysis tool that allowed us to follow the evolution of the microstructure and the dynamics of the grain orientation.

  5. Ionization Cluster Size Distributions Created by Low Energy Electrons and Alpha Particles in Nanometric Track Segment in Gases

    CERN Document Server

    Bantsar, Aliaksandr

    2012-01-01

    The interaction of ionizing radiation with nanometric targets is a field of interest for many branches of science such as: radiology, oncology, radiation protection and nanoelectronics. A new experimental technique known as nanodosimetry has been developed for the qualitative as well as quantitative description of these types of interactions. The work presented here is a contribution to this development, namely by further improvement of the new experimental technique called the Jet Counter, originally developed at the Andrzej So{\\l}tan Institute for Nuclear Studies. The Jet Counter is a unique device in the world for studying the interaction of low energy electrons with nanometer targets in the range 2-10 nm (in unit density). The basic experimental result is the frequency distribution of ionization cluster size produced by ionizing particles in a gaseous (nitrogen or propane) nanometric track segment. The first experimental data on the frequency distribution of ionization cluster size produced by low energy ...

  6. Cell engineering: nanometric grafting of poly-N-isopropylacrylamide onto polystyrene film by different doses of gamma radiation

    Directory of Open Access Journals (Sweden)

    Esmaeil Biazar

    2010-07-01

    Full Text Available Esmaeil Biazar1, Reza Zeinali2, Naser Montazeri1, Khalil Pourshamsian1, Mahmoud Jabarvand Behrouz3, Azadeh Asefnejad2, Ahad Khoshzaban3, Gholamreza Shahhosseini4, Mostafa Soleimannejad Najafabadi5, Reza Abyani2, Hamidreza Jamalzadeh6, Mahdi Fouladi1, Sasan Rahbar F Hagh7, Aylar Shams Khamaneh1, Soudabeh Kabiri1, Saeed Heidari Keshel3, Ana Mansourkiaei61Department of Chemistry, 6Department of Biology, 7Young Researchers Club, Islamic Azad University, Tonekabon Branch, Mazandaran, Iran; 2Biomedical Engineering Faculty, Islamic Azad University, Science and Research Branch, Tehran, Iran; 3Stem Cell Preparation Unit, Farabi Hospital, Tehran University Medical Science, Tehran, Iran; 4Agricultural, Medical and Industrial Research School, Nuclear Science and Techniques Research Institute, Karaj, Iran; 5Material Engineering Faculty, Islamic Azad University, Najafabad Branch, Isfahan, IranAbstract: Poly-N-isopropylacrylamide was successfully grafted onto a polystyrene cell culture dish and γ-preirradiated in air. In this study, the effect of a γ-pre-irradiation dose of radiation (radiation absorbed dosages of 10, 20, 30, 40 KGy under appropriate temperature and grafting conditions was investigated. The Fourier transform infrared spectroscopy analysis showed the existence of the graft poly-N-isopropylacrylamide (PNIPAAm on the substrate. The optimal value of the dose for grafting was 40 KGy at 50°C. The scanning electron microscopy and atomic force microscopy (AFM images clearly showed that increasing the absorbed dose of radiation would increase the amount of grafting. Surface topography and graft thickness in AFM images of the radiated samples showed that the PNIPAAm at the absorbed dose of radiation was properly grafted. The thickness of these grafts was about 50–100 nm. The drop water contact angles of the best grafted sample at 37°C and 10°C were 55.3 ± 1.2° and 61.2 ± 0.9° respectively, which showed the hydrophilicity and hydrophobicity of

  7. Structural and electrical properties of nanometric Ni-Cu ferrites synthesized by citrate precursor method

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, M.A., E-mail: moala47@hotmail.com [Materials Science Lab (1), Physics Department, Faculty of Science, Cairo University, Giza (Egypt); Mansour, S.F. [Physics Department, Faculty of Science, Zagazig University (Egypt); Afifi, M. [Materials Science Lab (1), Physics Department, Faculty of Science, Cairo University, Giza (Egypt)

    2012-01-15

    Nanometric nickel copper ferrites Ni{sub 1-x}Cu{sub x}Fe{sub 2}O{sub 4}, 0{<=}x{<=}0.45 were prepared by the citrate precursor method. X-ray diffraction measurements confirm the formation of single phase cubic spinel structure. The lattice parameter (a) is increased with increasing Cu{sup 2+} ion substitution. The crystallite size was calculated from XRD data and compared with that obtained from TEM micrographs. A significant increase in the density is observed with increasing Cu content. The IR absorption spectra were used for the detection and confirmation of the chemical bonds in spinel ferrites. The dielectric constant {epsilon}' and dielectric loss showed a decrease with increasing frequency for all samples. The decrease in the ac conductivity was ascribed to the increase in hopping length. - Highlights: > Ni-Cu ferrite was successfully prepared using citrate auto combustion method. > The lattice parameter and the density increased with increasing Cu{sup 2+} content. > We suggest the use of Ni ferrite with large Cu{sup 2+} content in electrical devices.

  8. Controlling optical responses through local dielectric resonance in nanometre metallic clusters

    Institute of Scientific and Technical Information of China (English)

    Chen Liang-Liang; Gu Ying; Wang Li-Jin; Gong Qi-Huang

    2007-01-01

    Optical responses in dilute composites are controlled through the local dielectric resonance of metallic clusters. We consider two located metallic clusters close to each other with admittances ε1 and ε2. Through varying the difference admittance ratio η[= (ε2 - ε0)/(ε1 - ε0)], we find that their optical responses are determined by the local resonance.There is a blueshift of absorption peaks with the increase of η. Simultaneously, it is known that the absorption peaks will be redshifted by enlarging the cluster size. By adjusting the nano-metallic cluster geometry, size and admittances,we can control the positions and intensities of absorption peaks effectively. We have also deduced the effective linear optical responses of three-comPonent composites εe = ε0 (1 + ∑nsn=1 [(γn1 + ηγn2 )/(ε0 (s - sn))]), and the sum rule of cross sections: ∑nsn=1 (γn1 + ηγn2) = Nh1 + Nh2, where Nh1and Nh2 are the numbers of ε1 and ε2 bonds along the electric field, respectively. These results may be beneficial to the study of surface plasmon resonances on a nanometre scale.

  9. Growth kinetics of nanometric dendrites in metal-carbon thin films

    Energy Technology Data Exchange (ETDEWEB)

    Corbella, C., E-mail: corbella@ub.edu [FEMAN Research Group, Institute of Nanoscience and Nanotechnology of the Universitat de Barcelona, c/Marti i Franques 1, E-08028 Barcelona (Spain); Echebarria, B.; Ramirez-Piscina, L. [Departament de Fisica Aplicada, Universitat Politecnica de Catalunya, Av. Doctor Maranon 44, E-08028 Barcelona (Spain); Pascual, E.; Andujar, J.L.; Bertran, E. [FEMAN Research Group, Institute of Nanoscience and Nanotechnology of the Universitat de Barcelona, c/Marti i Franques 1, E-08028 Barcelona (Spain)

    2009-10-15

    Tungsten-carbon films deposited by pulsed-DC reactive magnetron sputtering show the formation of a dendritic structure at the nanometric scale. The structure is formed by a combination of a polycrystalline {beta}-W phase together with a non-stoichiometric WC{sub 1-x} phase. The nanodendrites coincide with W-rich zones, whereas C-rich regions are located at the interstices. The characteristics of this nanostructure have been modulated by varying the metal concentration of the films. The composition, structure and morphology were characterized by X-ray photoelectron spectroscopy, electron probe microanalysis, transmission electron microscopy, X-ray diffraction and atomic force microscopy, and the mechanical and tribological properties were evaluated by profilometry, nanoindentation and microscratch. The observed growth pattern is interpreted as the result of nucleation and growth of a W phase into a W-C amorphous matrix, whose growth is controlled by diffusion of carbon. A simulation model based on phase field modelling and presenting similar morphologies is formulated. This special structure combines properties of W and diamond-like carbon films, which enlarges the scope of applications towards self-lubricating hard and low-friction coatings with improved stability.

  10. Influence of Nanometric Ceria Coating on Oxidation Behavior of Chromium at 900 ℃

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Isothermal and cyclic oxidation behaviors of chromium samples with and without nanometric CeO2 coating were studied at 900 ℃ in air. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution electron microscopy (HREM) were used to examine the morphology and microstructure of the oxide film. It was found that ceria coating greatly improved the oxidation resistance of Cr both in isothermal and cyclic oxidizing experiments. Acoustic emission (AE) technique was used in situ to monitor the cracking and spalling of oxide film, and AE signals were analyzed in time-domain and number-domain according to related oxide fracture model. Laser Raman spectrometer was also used to study the stress of oxide film formed on Cr with and without ceria. The improvement in oxidation resistance of chromium is believed mainly due to that ceria greatly reduced the growth speed and grain size of Cr2O3. This fine-grained Cr2O3 oxide film might have better high temperature plasticity and could relieve parts of the compressive stress by means of creeping and maintained ridge character and relatively lower level of internal stress. Meanwhile, ceria application reduced the size and number of interfacial defects, remarkably enhanced the adhesive property of Cr2O3 oxide scale formed on Cr substrate.

  11. Single Nanometric Memory Unit Based On a Protein-Nanoparticle Hybrid

    Science.gov (United States)

    Medalsy, Izhar; Heyman, Arnon; Shoseyov, Oded; Porath, Danny

    2009-03-01

    Proteins as an isolating template and nanoparticle (NP) as an electric storage component can form a single addressable unit cell isolated from the conductive surface and adjacent NPs. This setup gives rise to a wide range of nanoelectronic applications. Here we demonstrate, by Conductive AFM, a single nanometric memory unit using individual protein-NP hybrids. SP1 is a boiling-stable ring-shaped protein, 11 nm in diameter. Mutants of SP1 were synthesized allowing its selective attachment to gold surface and the formation of 2D arrays using methods such as phospholipids trough and Langmuir Blodgett. The SP1 inner pore was connected to Si NP forming a chargeable entity embedded in an isolating unit over a conductive surface. Each NP holds three charging states: natural, positive and negative. The charging life times are 10 min in ambient and days in vacuum. Using this setup, and the relative long charging time, we were able to apply a read and write operations on individual 5nm Si NP embedded in a stable protein.

  12. An effective method to probe local magnetostatic properties in a nanometric FePd antidot array

    Energy Technology Data Exchange (ETDEWEB)

    Beron, F; Pirota, K R; Knobel, M [Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, Rua Sergio Buarque de Holanda, 777, Cidade Universitaria ' Zeferino Vaz' , Campinas 13083-859, SP (Brazil); Vega, V; Prida, V M; Fernandez, A; Hernando, B, E-mail: fberon@ifi.unicamp.br [Depto. Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo, Asturias (Spain)

    2011-01-15

    A simple method to quantitatively characterize the local magnetic behaviour of a patterned nanostructure, like a ferromagnetic thin film of antidot arrays, is proposed. The first-order reversal curve (FORC) analysis, coupled with simulations using physically meaningful hysterons, allows us to obtain a quantitative and physically related description of the interaction field and each magnetization reversal process. The hysterons system is built from previously known hypotheses on the magnetic behaviour of the sample. This method was successfully applied to a highly hexagonal ordered FePd antidot array with nanometric dimensions. We achieved a complete characterization of the two different magnetization reversal mechanisms in function of the in-plane applied field angle. For a narrow range of high fields, the magnetization initiates rotating reversibly around the pores, while at lower fields, domain walls are nucleated and propagated. This in-plane magnetization reversal mechanism, partly reversible and partly irreversible, is the only angularly dependent one. While going away from the easy axis, its reversible proportion increases, as well as its switching field distribution. Finally, the results indicate that the high surface roughness between adjacent holes of the antidot thin film induces a parallel interaction field. The proposed method demonstrates its ability also to be applied to characterizing patterned nanostructures with rather complex magnetization reversal processes.

  13. High temperature oxidation of chromium with nanometric ceria sol-gel coating

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Isothermal oxidation behavior of chromium with and without nanometric sol-gel CeO2 coating is studied at 1000℃ in air. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are used to examine the surface morphology and microstructure of their oxide films. It is found that ceria coating greatly improves the anti-oxidation property of chromium. Laser Raman spectrometer and X-ray diffraction spectrometer (XRD) are also used to study the stress level in oxide films formed on ceria-coated and ceria-free Cr. The difference in oxidation behavior is mainly attributed to the fact that ceria greatly reduces the growth speed and grain size of Cr2O3 film, and this fine grain-sized Cr2O3 film probably has better high temperature plasticity, i.e. oxide film can relieve parts of compressive stress by means of creeping. XRD and Raman testing results both show the stress declination due to nano-CeO2 application, and their deviation is analyzed concerning to the rare earth effect.

  14. Influence of nanometric CeO2 coating on high temperature oxidation of Cr

    Institute of Scientific and Technical Information of China (English)

    Jin Huiming; Zhang Linnan; Liu Xiaojun

    2007-01-01

    Isothermal and cyclic oxidation behavior of chromium and its superficially applied nanometric CeO2 samples were studied at 900℃ in air. Scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and high resolution electronic microscopy (HREM) were used to examine the morphology and micro-structure of oxide films. It was found that ceria addition greatly improved the anti-oxidation ability of Cr both in isothermal and cyclic oxidizing experiments. Acoustic emission (AE) technique was used in situ to monitor the cracking and spalling of oxide films, and AE signals were analyzed in time-domain and number-domain according to the related oxide fracture model. Laser Raman spectrometer was also used to study the stress status of oxide films formed on Cr with and without ceria. The main reason for the improvement in anti-oxidation of chromium was that ceria greatly reduced the growing speed and grain size of Cr2O3. This fine-grained Cr2O3 oxide film might have better high temperature plasticity and could relieve parts of compressive stress by means of creeping, and maintained the ridge character and relatively low internal stress level. Meanwhile, ceria application reduced the size and the number of interfacial defects, while remarkably enhanced the adhesive property of Cr2O3 oxide scale formed on Cr substrate.

  15. Stabilization and Fine Positioning to the Nanometre Level of the CLIC Main Beam Quadrupoles

    CERN Document Server

    Artoos, K; Fernandez Carmona, P; Guinchard, M; Hauviller, C; Janssens, S; Kuzmin, A; Lackner, F; Leuxe, R; Slaathaug, A

    2010-01-01

    The CLIC main beam quadrupoles need to be stabilized to 1.5 nm integrated R.M.S. displacement at 1 Hz. The choice was made to apply active stabilization with piezoelectric actuators in a rigid support with flexural guides. The advantages of this choice are the robustness against external forces and the possibility to make fast incremental nanometre positioning of the magnet with the same actuators. The study and feasibility demonstration is made in several steps from a single degree of freedom system (s.d.o.f.) with a small mass, a s.d.o.f. with a large mass, leading to the demonstration including the smallest (type 1) and largest (type 4) CLIC main beam quadrupoles. The paper discusses the choices of the position and orientation of the actuators and the tailored rigidities of the flexural hinges in the multi degree of freedom system, and the corresponding MIMO control system. The compatibility with the magnet support and micrometre alignment system is essential. The status of the study and performed tests wi...

  16. Characterization of Nanometric-Sized Carbides Formed During Tempering of Carbide-Steel Cermets

    Directory of Open Access Journals (Sweden)

    Matus K.

    2016-06-01

    Full Text Available The aim of this article of this paper is to present issues related to characterization of nanometric-sized carbides, nitrides and/or carbonitrides formed during tempering of carbide-steel cermets. Closer examination of those materials is important because of hardness growth of carbide-steel cermet after tempering. The results obtained during research show that the upswing of hardness is significantly higher than for high-speed steels. Another interesting fact is the displacement of secondary hardness effect observed for this material to a higher tempering temperature range. Determined influence of the atmosphere in the sintering process on precipitations formed during tempering of carbide-steel cermets. So far examination of carbidesteel cermet produced by powder injection moulding was carried out mainly in the scanning electron microscope. A proper description of nanosized particles is both important and difficult as achievements of nanoscience and nanotechnology confirm the significant influence of nanocrystalline particles on material properties even if its mass fraction is undetectable by standard methods. The following research studies have been carried out using transmission electron microscopy, mainly selected area electron diffraction and energy dispersive spectroscopy. The obtained results and computer simulations comparison were made.

  17. Can conventional phase-change memory devices be scaled down to single-nanometre dimensions?

    Science.gov (United States)

    Hayat, Hasan; Kohary, Krisztian; Wright, C. David

    2017-01-01

    The scaling potential of ‘mushroom-type’ phase-change memory devices is evaluated, down to single-nanometre dimensions, using physically realistic simulations that combine electro-thermal modelling with a Gillespie Cellular Automata phase-transformation approach. We found that cells with heater contact sizes as small as 6 nm could be successfully amorphized and re-crystallized (RESET and SET) using moderate excitation voltages. However, to enable the efficient formation of amorphous domes during RESET in small cells (heater contact diameters of 10 nm or less), it was necessary to improve the thermal confinement of the cell to reduce heat loss via the electrodes. The resistance window between the SET and RESET states decreased as the cell size reduced, but it was still more than an order of magnitude even for the smallest cells. As expected, the RESET current reduced as the cells got smaller; indeed, RESET current scaled with the inverse of the heater contact diameter and ultra-small RESET currents of only 19 μA were achieved for the smallest cells. Our results show that the conventional mushroom-type phase-change cell architecture is scalable and operable in the sub-10nm region.

  18. Analysis of DC Electrical Conductivity Models of Carbon Nanotube-Polymer Composites with Potential Application to Nanometric Electronic Devices

    OpenAIRE

    Rafael Vargas-Bernal; Gabriel Herrera-Pérez; Ma. Elena Calixto-Olalde; Margarita Tecpoyotl-Torres

    2013-01-01

    The design of nanometric electronic devices requires novel materials for improving their electrical performance from stages of design until their fabrication. Until now, several DC electrical conductivity models for composite materials have been proposed. However, these models must be valued to identify main design parameters that more efficiently control the electrical properties of the materials to be developed. In this paper, four different models used for modeling DC electrical conductivi...

  19. Optimum synthesis conditions of nanometric Fe50Ni50 alloy formed by chemical reduction in aqueous solution

    Indian Academy of Sciences (India)

    Marwa A Mohamed; Azza H El-Maghraby; Mona M Abd El-Latif; Hassan A Farag

    2013-10-01

    In the present article, various nanometric Fe50Ni50 alloys were synthesized by chemical reduction of the corresponding metal ions, with hydrazine in an aqueous solution. Process variables of reaction temperature, pH of the hydrazine solution and concentration of metal ions were varied in order to determine the optimum synthesis conditions regarding quality, productivity and cost. It is found that pH of hydrazine solution, at low concentration of metal ions, is the most crucial variable affecting the reaction rate, average crystallite and particle sizes of the synthesized nanometric Fe50Ni50 alloy, followed by the total concentration of metal ions. Thus, increase of pH of hydrazine solution acts as an efficient stabilizer in reducing the particle size. On the contrary, at high concentration of metal ions, the structural characteristics of the nanometric Fe50Ni50 alloy are almost insensitive to reaction temperature and pH of hydrazine solution, but the reduction rate is remarkably sensitive to reaction temperature. Based on these results, it is decided that a reaction temperature of 80 °C, pH of the hydrazine solution of 12.5 and concentration of metal ions of 0.6 M represent the optimum synthesis conditions. The role of pH of hydrazine solution in reducing the alloy’s average particle size as well as efficient stabilizer confirms tremendous effect of synthesis conditions on the alloy structure and therefore, the importance of this study for industrial production of nanometric Fe50Ni50 alloy.

  20. Evaluation of knee-joint cartilage and menisci ten years after isolated and combined ruptures of the medial collateral ligament. Investigation by weight-bearing radiography, MR imaging and analysis of proteoglycan fragments in the joint fluid

    Energy Technology Data Exchange (ETDEWEB)

    Lundberg, M. [Univ. Hospital, Linkoeping (Sweden). Dept. of Orthopaedics and Sports Medicine (Sweden); Thuomas, K.Aa. [Univ. Hospital, Linkoeping (Sweden). Dept. of Diagnostic Radiology; Messner, K. [Univ. Hospital, Linkoeping (Sweden). Dept. of Orthopaedics and Sports Medicine (Sweden)

    1997-01-01

    Purpose: To compare radiography, MR imaging, and chemical analysis in posttraumatic knees. Material and Methods: Ten matched pairs with either isolated partial rupture of the medial collateral ligament or combined medial collateral ligament/anterior cruciate ligament rupture were compared with matched controls 10 years after trauma. Weight-bearing radiographys and MR examinations were compared with proteoglycan fragment concentrations in the joint fluid. Results: The chemical analyses were similar in both trauma groups. The radiographs showed mild signs of arthrosis in half the patients with combined injury. MR images showed almost all injuried knees to have degenerative changes of various degrees in the cartilage and menisci. More frequent and more advanced changes were found after combined injury than after isolated injury (p<0.01). There were no changes in the controls. Conclusion: MR imaging is the best method for detecting and differentiating early posttraumatic knee arthrosis. (orig.).

  1. Synthesis and characterization of nanometric magnetite coated by oleic acid and the surfactant CTAB

    Energy Technology Data Exchange (ETDEWEB)

    Celis, J. Almazán, E-mail: jony-jac-5@hotmail.com; Olea Mejía, O. F., E-mail: oleaoscar@yahoo.com [Universidad Autónoma del Estado de México, Centro Conjunto de Investigación en Química Sustentable UAEMéx-UNAM (Mexico); Cabral-Prieto, A., E-mail: agustin.cabral@inin.gob.mx; García-Sosa, I., E-mail: irma.garcia@inin.gob.mx [Instituto Nacional de Investigaciones Nucleares (Mexico); Derat-Escudero, R., E-mail: escu@unam.mx [Instituto de Investigación de materiales de la UNAM (Mexico); Baggio Saitovitch, E. M., E-mail: esaitovitch@yahoo.com.br; Alzamora Camarena, M., E-mail: mariella.alzamora@gmail.com [Centro Brasileiro de Pesquizas Físicas (Brazil)

    2017-11-15

    Nanometric magnetite (nm-Fe{sub 3}O{sub 4}) particles were prepared by the reverse co-precipitation synthesis method, obtaining particle sizes that ranged from 4 to 8.5 nm. In their synthesis, the concentration of iron salts of ferric nitrate, Fe(NO{sub 3}){sub 3}⋅9H{sub 2}O, and ferrous sulfate, FeSO{sub 4}⋅7H{sub 2}O, were varied relative to the chemical reaction volume and by using different surfactants such as oleic acid (OA) and hexadecyltrimethylammonium bromide (CTAB). The nm-Fe{sub 3}O{sub 4} particles were characterized by transmission electron microscopy (TEM), Mössbauer spectroscopy (MS), magnetic and X-ray diffraction (XRD) measurements. Typical asymmetrical and/or broad lines shapes appeared in all Mössbauer spectra of the as prepared samples suggesting strong magnetic inter-particle interactions, reducing these interactions to some extent by gentle mechanical grinding. For the smallest particles, maghemite instead of magnetite was the main preparation product as low temperature Mössbauer and magnetic measurements indicated. For the intermediate and largest particles a mixture of magnetite and maghemite phases were produced as the saturation magnetization values of M{sub S} ∼ 60 emu/g indicated; these values were measured for most samples, independently of the coating surfactant concentration, and according to the ZFC-FC curves the blocking temperatures were 225K and 275K for the smallest and largest magnetite nanoparticles, respectively. The synthesis method was highly reproducible.

  2. Water-walking devices

    Science.gov (United States)

    Hu, David L.; Prakash, Manu; Chan, Brian; Bush, John W. M.

    We report recent efforts in the design and construction of water-walking machines inspired by insects and spiders. The fundamental physical constraints on the size, proportion and dynamics of natural water-walkers are enumerated and used as design criteria for analogous mechanical devices. We report devices capable of rowing along the surface, leaping off the surface and climbing menisci by deforming the free surface. The most critical design constraint is that the devices be lightweight and non-wetting. Microscale manufacturing techniques and new man-made materials such as hydrophobic coatings and thermally actuated wires are implemented. Using highspeed cinematography and flow visualization, we compare the functionality and dynamics of our devices with those of their natural counterparts.

  3. Analysis of DC Electrical Conductivity Models of Carbon Nanotube-Polymer Composites with Potential Application to Nanometric Electronic Devices

    Directory of Open Access Journals (Sweden)

    Rafael Vargas-Bernal

    2013-01-01

    Full Text Available The design of nanometric electronic devices requires novel materials for improving their electrical performance from stages of design until their fabrication. Until now, several DC electrical conductivity models for composite materials have been proposed. However, these models must be valued to identify main design parameters that more efficiently control the electrical properties of the materials to be developed. In this paper, four different models used for modeling DC electrical conductivity of carbon nanotube-polymer composites are studied with the aim of obtaining a complete list of design parameters that allow guarantying to the designer an increase in electrical properties of the composite by means of carbon nanotubes.

  4. High-quality ion beams from a nanometric double-layer target and their application to hadron-therapy

    CERN Document Server

    Grech, M; Nuter, R; Grémillet, L; Lefebvre, E

    2010-01-01

    The production of ion beams from the interaction of a circularly polarized laser pulse with a nanometric double-layer target is discussed in the regime where all electrons are expelled from the target by the laser radiation pressure. Quasi-monochromatic, well-collimated ion beams are observed in two-dimensional particle-in-cell simulations. The ion beam properties are derived from a simple analytical model, and the possibility to control those properties by using a laser-pulse with sharp-rising edge is discussed. Application to hadron-therapy is finally considered.

  5. Laser spectroscopy with nanometric gas cells distance dependence of atom-surface interaction and collisions under confinement

    CERN Document Server

    Hamdi, I; Yarovitski, A; Dutier, G; Maurin, I; Saltiel, S; Li, Y; Lezama, A; Vartapetyan, T; Sarkisyan, D; Gorza, M P; Fichet, M; Bloch, D; Ducloy, M; Hamdi, Ismah\\`{e}ne; Todorov, Petko; Yarovitski, Alexander; Dutier, Gabriel; Maurin, Isabelle; Saltiel, Solomon; Li, Yuanyuan; Lezama, Arturo; Varzhapetyan, Tigran; Sarkisyan, David; Gorza, Marie-Pascale; Fichet, Mich\\`{e}le; Bloch, Daniel; Ducloy, Martial

    2005-01-01

    The high sensitivity of Laser Spectroscopy has made possible the exploration of atomic resonances in newly designed "nanometric" gas cells, whose local thickness varies from 20nm to more than 1000 nm. Following the initial observation of the optical analogous of the coherent Dicke microwave narrowing, the newest prospects include the exploration of long-range atom surface van der Waals interaction with spatial resolution in an unprecedented range of distances, modification of atom dielectric resonant coupling under the influence of the coupling between the two neighbouring dielectric media, and even the possible modification of interatomic collisions processes under the effect of confinement.

  6. Diffraction pattern by nanometric thin films under illumination of an orbital angular momentum beam with integer topological charge

    Science.gov (United States)

    Mendoza, J. H.; Díaz, C. F.; Acevedo, C. H.; Torres, Y.

    2016-02-01

    The orbital angular momentum of light has a big contribution in many engineering applications like optical communications, because this physical property allows eigenstates characteristic of the wavefront rotation when the beam is propagated. The nature of these eigenstates allows that information can be encoded and gives immunity to electromagnetic interference, allowing an increase of bandwidth, cadence and capacity of the communication channel. This work shown the methodology using nanometric thin films like Titanium based (TiO2) grown over strontium titanate (SrTiO3) support, to distinguish and discriminate a well- defined integer value of the topological charge of an OAM beam.

  7. Effects of different preservation temperatures and periods menisci cellularity in rabbits Efeitos de diferentes temperaturas e períodos de preservação na celularidade de meniscos em coelhos

    Directory of Open Access Journals (Sweden)

    Leandro José Reckers

    2005-12-01

    Full Text Available PURPOSE: Quantify the progressive decrease of the cellular viability of rabbit meniscus preserved for transplants over a 30 day period at different freezing temperatures. METHODS: 180 menisci were removed from 45 rabbits. Menisci were frozen from 2 to 30 days at -7.2°Celsius -21.4°Celsius and -73°Celsius. Four menisci from each temperature were thawed every two days and the number of present cells was quantified. RESULTS: On the 14th freezing day at -7.2°Celsius, there were 92.38% mean viable cells. However, as from the 16th day, there has been a significant 12% decrease (p = 0.001, as compared to 14th day mean. Mean cell viability at -21.4°Celsius and -73ºCelsius, until the 16th day was statistically similar. As from the 18th day at -21.4°Celsius, there has been significant cell count decrease (p OBJETIVO: Quantificar a diminuição progressiva da viabilidade celular de meniscos de coelhos preservados para transplantes durante trinta dias em três temperaturas diferentes de congelamento. MÉTODOS: Retirou-se 180 meniscos de 45 coelhos. Os meniscos foram congelados, de dois até trinta dias, a -7,2°Celsius -21,4°Celsius e -73°Celsius. A cada dois dias, de cada temperatura, foram descongelados quatro meniscos e quantificou-se o número de células presentes. RESULTADOS: No 14º dia de congelamento a -7,2°Celsius, a média de células viáveis foi de 92,38%. Entretanto, a partir do 16º dia observou-se uma redução significante de 12% (p=0,001, comparando-se com a média no 14° dia. A média da viabilidade celular, nas temperaturas -21,4°Celsius e -73ºCelsius, até 16º dia apresentou comportamento estatisticamente semelhante. A partir do 18º dia na temperatura de -21,4°Celsius a redução do número de células foi significante (p<0,001, especialmente do 28° (54,5% para o 30° dia (30% de congelamento. O número de células viáveis a -73°Celsius mostrou uma redução não significante (p=1,000 de 2,3% no número de células vi

  8. Far field optical nanoscopy: How far can you go in nanometric characterization without resolving all the details?

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, Paul C., E-mail: paul.montgomery@unistra.fr [Laboratoire des Sciences de l’Ingénieur, de l’Informatique et de l’Imagerie (ICube), UDS-CNRS, UMR 7367, 23 rue du Loess, 67037 Strasbourg (France); Serio, Bruno; Anstotz, Freddy; Montaner, Denis [Laboratoire des Sciences de l’Ingénieur, de l’Informatique et de l’Imagerie (ICube), UDS-CNRS, UMR 7367, 23 rue du Loess, 67037 Strasbourg (France)

    2013-09-15

    In the development of nanomaterials and biomaterials, new characterization techniques are required that overcome the challenges presented by the increasing dimensional ratio between the different entities to be studied and the growing complexity introduced by the use of heterogeneous materials and technologies. Diffraction limited far field optical nanoscopy techniques are receiving growing interest because of their ability to detect nanometer structures over very large fields and at high speed. We present a classification scheme of the different types of optical nanoscopy techniques. In particular, we highlight four categories of far field diffraction limited techniques based on increasing the contrast, measuring the phase, using deconvolution and using nano-markers. We demonstrate that by increasing the power of detectability, observability or measurability, a wealth of information concerning nanometric structures becomes available even though all the lateral details may not be resolved. For example, it is possible to determine the presence, the structure and orientation of nanostructures, to measure their density, position and 2D and 3D distribution and to measure nanometric surface roughness in bulk materials, surfaces, nano-layers, soft matter and cells. These techniques conserve all the advantages associated with classical imaging such as real time imaging, non-invasiveness, non-destructiveness and ease of use.

  9. Finishing of AT-cut quartz crystal wafer with nanometric thickness uniformity by pulse-modulated atmospheric pressure plasma etching.

    Science.gov (United States)

    Yamamura, Kazuya; Ueda, Masaki; Shibahara, Masafumi; Zettsu, Nobuyuki

    2011-04-01

    Quartz resonator is a very important device to generate a clock frequency for information and telecommunication system. Improvement of the productivity of the quartz resonator is always required because a huge amount of the resonator is demanded for installing to various electronic devices. Resonance frequency of the quartz resonator is decided by the thickness of the quartz crystal wafer. Therefore, it is necessary to uniform the thickness distribution of the wafer with nanometric level. We have proposed the improvement technique of the thickness distribution of the quartz crystal wafer by numerically controlled correction using atmospheric pressure plasma which is non-contact and chemical removal technique. Heating effects of the quartz wafer in the removal rate and the correction accuracy were investigated. The heating of the substrate and compensate of the scanning speed of the worktable according to the variation of the surface temperature enabled an increase of 50% in the etching rate and 10-nanometric-level accuracy in the correction of the thickness distribution of the quartz wafer, respectively.

  10. Sub-nanometre resolution imaging of polymer–fullerene photovoltaic blends using energy-filtered scanning electron microscopy

    Science.gov (United States)

    Masters, Robert C.; Pearson, Andrew J.; Glen, Tom S.; Sasam, Fabian-Cyril; Li, Letian; Dapor, Maurizio; Donald, Athene M.; Lidzey, David G.; Rodenburg, Cornelia

    2015-01-01

    The resolution capability of the scanning electron microscope has increased immensely in recent years, and is now within the sub-nanometre range, at least for inorganic materials. An equivalent advance has not yet been achieved for imaging the morphologies of nanostructured organic materials, such as organic photovoltaic blends. Here we show that energy-selective secondary electron detection can be used to obtain high-contrast, material-specific images of an organic photovoltaic blend. We also find that we can differentiate mixed phases from pure material phases in our data. The lateral resolution demonstrated is twice that previously reported from secondary electron imaging. Our results suggest that our energy-filtered scanning electron microscopy approach will be able to make major inroads into the understanding of complex, nano-structured organic materials. PMID:25906738

  11. Sub-nanometre resolution imaging of polymer-fullerene photovoltaic blends using energy-filtered scanning electron microscopy.

    Science.gov (United States)

    Masters, Robert C; Pearson, Andrew J; Glen, Tom S; Sasam, Fabian-Cyril; Li, Letian; Dapor, Maurizio; Donald, Athene M; Lidzey, David G; Rodenburg, Cornelia

    2015-04-24

    The resolution capability of the scanning electron microscope has increased immensely in recent years, and is now within the sub-nanometre range, at least for inorganic materials. An equivalent advance has not yet been achieved for imaging the morphologies of nanostructured organic materials, such as organic photovoltaic blends. Here we show that energy-selective secondary electron detection can be used to obtain high-contrast, material-specific images of an organic photovoltaic blend. We also find that we can differentiate mixed phases from pure material phases in our data. The lateral resolution demonstrated is twice that previously reported from secondary electron imaging. Our results suggest that our energy-filtered scanning electron microscopy approach will be able to make major inroads into the understanding of complex, nano-structured organic materials.

  12. A new method for measuring ion clusters produced by charged particles in nanometre track sections of DNA size

    Science.gov (United States)

    Pszona, S.; Kula, J.; Marjanska, S.

    2000-06-01

    A new method is presented for measuring the frequency distribution of ion clusters, formed in nanometre sections of track, by charged particles. The simulated nanometer-size sites are produced in a device, called the Jet Counter. It consists of a pulse-operated valve which injects an expanding jet of nitrogen gas into an interaction chamber. The resulting distributions of ion clusters produced by alpha particle tracks (from 241Am) in sections ranging from 2 to around 10 nm at unit density in nitrogen gas have been measured. Analysis of the experimental results confirm that the primary ionisation distributions produced in the nanometer sections comply with the Poisson distribution. The ionisation cluster distributions produced in the 2-10 nm track-segments are the first ever to be determined experimentally.

  13. A new method for measuring ion clusters produced by charged particles in nanometre track sections of DNA size

    Energy Technology Data Exchange (ETDEWEB)

    Pszona, S. E-mail: pszona@ipj.gov.pl; Kula, J.; Marjanska, S

    2000-06-11

    A new method is presented for measuring the frequency distribution of ion clusters, formed in nanometre sections of track, by charged particles. The simulated nanometer-size sites are produced in a device, called the Jet Counter. It consists of a pulse-operated valve which injects an expanding jet of nitrogen gas into an interaction chamber. The resulting distributions of ion clusters produced by alpha particle tracks (from {sup 241}Am) in sections ranging from 2 to around 10 nm at unit density in nitrogen gas have been measured. Analysis of the experimental results confirm that the primary ionisation distributions produced in the nanometer sections comply with the Poisson distribution. The ionisation cluster distributions produced in the 2-10 nm track-segments are the first ever to be determined experimentally.

  14. Accelerator and Technical Sector Seminar: Mechanical stabilization and positioning of CLIC quadrupoles with sub-nanometre resolution

    CERN Multimedia

    2011-01-01

    Thursday 24 November 2010 Accelerator and Technical Sector Seminar at 14:15  -  BE Auditorium, bldg. 6 (Meyrin) – please note unusual place Mechanical stabilization and positioning of CLIC quadrupoles with sub-nanometre resolution Stef Janssens /EN-MME Abstract: To reach the required luminosity at the CLIC interaction point, about 4000 quadrupoles are needed to obtain a vertical beam size of 1 nm at the interaction point. The mechanical jitter of the quadrupole magnets will result in an emittance growth. An active vibration isolation system is required to reduce vibrations from the ground and from external forces to about 1.5 nm integrated root mean square (r.m.s.) vertical displacement at 1 Hz. A short overview of vibration damping and isolation strategies will be presented as well as a comparison of existing systems. The unprecedented resolution requirements and the instruments enabling these measurements will be discussed. The vibration sources from which the magnets need to...

  15. Amorphous sub-nanometre Tb-doped SiO(x)N(y)/SiO2 superlattices for optoelectronics.

    Science.gov (United States)

    Ramírez, Joan Manel; Wojcik, Jacek; Berencén, Yonder; Ruiz-Caridad, Alícia; Estradé, Sònia; Peiró, Francesca; Mascher, Peter; Garrido, Blas

    2015-02-27

    Amorphous sub-nanometre Tb-doped SiOxNy/SiO2 superlattices were fabricated by means of alternating deposition of 0.7 nm thick Tb-doped SiOxNy layers and of 0.9 nm thick SiO2 barrier layers in an electron-cyclotron-resonance plasma enhanced chemical vapour deposition system with in situ Tb-doping capability. High resolution transmission electron microscopy images showed a well-preserved superlattice morphology after annealing at a high temperature of 1000 °C. In addition, transparent indium tin oxide (ITO) electrodes were deposited by electron beam evaporation using a shadow mask approach to allow for the optoelectronic characterization of superlattices. Tb(3+) luminescent spectral features were obtained using three different excitation sources: UV laser excitation (photoluminescence (PL)), under a bias voltage (electroluminescence (EL)) and under a highly energetic electron beam (cathodoluminescence (CL)). All techniques displayed Tb(3+) inner transitions belonging to (5)D4 levels except for the CL spectrum, in which (5)D3 transition levels were also observed. Two competing mechanisms were proposed to explain the spectral differences observed between PL (or EL) and CL excitation: the population rate of the (5)D3 state and the non-radiative relaxation rate of the (5)D3-(5)D4 transition due to a resonant OH-mode. Moreover, the large number of interfaces (trapping sites) that electrons have to get through was identified as the main reason for observing a bulk-limited charge transport mechanism governed by Poole-Frenkel conduction in the J-V characteristic. Finally, a linear EL-J dependence was measured, with independent spectral shape and an EL onset voltage as low as 6.7 V. These amorphous sub-nanometre superlattices are meant to provide low-cost solutions in different areas including sensing, photovoltaics or photonics.

  16. Phase Identification of Nanometric Precipitates in Al-Si-Cu Aluminum Alloy by Hr-Stem Investigations

    Directory of Open Access Journals (Sweden)

    Pawlyta M.

    2016-09-01

    Full Text Available Aluminium recycling is cost-effective and beneficial for the environment. It is expected that this trend will continue in the future, and even will steadily increase. The consequence of the use of recycled materials is variable and difficult to predict chemical composition. This causes a significant reduction in the production process, since the properties of produced alloy are determined by the microstructure and the presence of precipitates of other phases. For this reason, the type and order of formation of precipitates were systematically investigated in recent decades. These studies involved, however, only the main systems (Al-Cu, Al-Mg-Si, Al-Cu-Mg, Al-Mg-Si-Cu, while more complex systems were not analysed. Even trace amounts of additional elements can significantly affect the alloy microstructure and composition of precipitates formed. This fact is particularly important in the case of new technologies such as laser surface treatment. As a result of extremely high temperature and temperature changes after the laser remelting large amount of precipitates are observed. Precipitates are nanometric in size and have different morphology and chemical composition. A full understanding of the processes that occur during the laser remelting requires their precise but also time effectively phase identification, which due to the diversity and nanometric size, is a major research challenge. This work presents the methodology of identification of nanometer phase precipitates in the alloy AlSi9Cu, based on the simultaneous TEM imaging and chemical composition analysis using the dispersion spectroscopy using the characteristic X-ray. Verification is performed by comparing the simulation unit cell of the identified phase with the experimental high-resolution image.

  17. Amorphous sub-nanometre Tb-doped SiOxNy/SiO2 superlattices for optoelectronics

    Science.gov (United States)

    Ramírez, Joan Manel; Wojcik, Jacek; Berencén, Yonder; Ruiz-Caridad, Alícia; Estradé, Sònia; Peiró, Francesca; Mascher, Peter; Garrido, Blas

    2015-02-01

    Amorphous sub-nanometre Tb-doped SiOxNy/SiO2 superlattices were fabricated by means of alternating deposition of 0.7 nm thick Tb-doped SiOxNy layers and of 0.9 nm thick SiO2 barrier layers in an electron-cyclotron-resonance plasma enhanced chemical vapour deposition system with in situ Tb-doping capability. High resolution transmission electron microscopy images showed a well-preserved superlattice morphology after annealing at a high temperature of 1000 °C. In addition, transparent indium tin oxide (ITO) electrodes were deposited by electron beam evaporation using a shadow mask approach to allow for the optoelectronic characterization of superlattices. Tb3+ luminescent spectral features were obtained using three different excitation sources: UV laser excitation (photoluminescence (PL)), under a bias voltage (electroluminescence (EL)) and under a highly energetic electron beam (cathodoluminescence (CL)). All techniques displayed Tb3+ inner transitions belonging to 5D4 levels except for the CL spectrum, in which 5D3 transition levels were also observed. Two competing mechanisms were proposed to explain the spectral differences observed between PL (or EL) and CL excitation: the population rate of the 5D3 state and the non-radiative relaxation rate of the 5D3-5D4 transition due to a resonant OH-mode. Moreover, the large number of interfaces (trapping sites) that electrons have to get through was identified as the main reason for observing a bulk-limited charge transport mechanism governed by Poole-Frenkel conduction in the J-V characteristic. Finally, a linear EL-J dependence was measured, with independent spectral shape and an EL onset voltage as low as 6.7 V. These amorphous sub-nanometre superlattices are meant to provide low-cost solutions in different areas including sensing, photovoltaics or photonics.

  18. K-Ar dating and delta O-18-delta D characterization of nanometric illite from Ordovician K-bentonites of the Appalachians: illitization and the Acadian-Alleghenian tectonic activity

    Science.gov (United States)

    Clauer, Norbert; Fallick, Anthony E.; Eberl, Dennis D.; Honty, Miroslav; Huff, Warren D.; Auberti, Amelie

    2013-01-01

    Nanometric (2 diagram that illitization occurred in all fractions by simultaneous nucleation and crystal growth, except for one sample. In that sample, a period of growth without nucleation was detected on top of the nucleation and growth episode. The K-Ar ages organize into two isochrons, the first at 319.9 ± 2.0 Ma with an initial 40Ar/36Ar ratio of 271 ± 66 Ma, and the second at 284.9 ± 1.2 Ma with an initial 40Ar/36Ar ratio of 310 ± 44. One data point above the older isochron and three between the two isochrons suggest a detrital contamination for the former separate and a possible further generation of nanoparticles for the three others. The samples with the older crystallization age consist of illite and illite-rich mixed-layers, and those with the younger age contain smectite-rich mixed-layers without illite, or illite-enriched illite-smectite mixed-layers. The K-Ar ages fit the age trends published previously for similar K-bentonites with regional age patterns between 240 and 270 Ma in the southwestern region, between 270 and 300 Ma in the central zone and the southern Appalachians, and between 315 and 370 Ma in the northernmost. Each of the two generations of illite crystals yields very consistent δ18O (V-SMOW) values at 17 ± 1‰ for the older and at 21 ± 1‰ for the younger. If crystallization temperatures of the nanometric illite were between 100 and 200 °C, as suggested by microthermometric determinations, the hydrothermal fluids had δ18O values of 4 ± 1‰ in the Dalton district and of 8 ± 1‰ in the Lafayette, Trenton, and Dirtseller districts at 100 °C, and of 11 ± 1 and 15 ± 1‰ in the same locations at 200 °C, probably because the water-rock isotope exchanges at elevated temperature occurred in rock-dominated systems. The δ18O of the fluids remained unchanged during local crystal growth, but varied depending on the geographic location of the samples and timing of illitization. The δD (V-SMOW) values of the different size

  19. Water

    Science.gov (United States)

    ... www.girlshealth.gov/ Home Nutrition Nutrition basics Water Water Did you know that water makes up more ... to drink more water Other drinks How much water do you need? top Water is very important, ...

  20. Hard Alloy Synthesis from Tungsten-containing Electroerosion Powders of Micro- and Nanometric Fractions

    Directory of Open Access Journals (Sweden)

    E.V. Ageev

    2014-07-01

    Full Text Available The article presents the results of the studies of the composition, structure and properties of the hard alloy produced using hot-pressing technique with the high current passage from the powder produced using electroerosion dispersion of sintered hard alloys wastes in lamp kerosene and distilled water.

  1. Nanometric Graphene Oxide Framework Membranes with Enhanced Heavy Metal Removal via Nanofiltration.

    Science.gov (United States)

    Zhang, Yu; Zhang, Sui; Chung, Tai-Shung

    2015-08-18

    A novel dual-modification strategy, including (1) the cross-linking and construction of a GO framework by ethylenediamine (EDA) and (2) the amine-enrichment modification by hyperbranched polyethylenimine (HPEI), has been proposed to design stable and highly charged GO framework membranes with the GO selective layer thickness of 70 nm for effective heave metal removal via nanofiltration (NF). Results from sonication experiments and positron annihilation spectroscopy confirmed that EDA cross-linking not only enhanced structural stability but also enlarged the nanochannels among the laminated GO nanosheets for higher water permeability. HPEI 60K was found to be the most effective post-treatment agent that resulted in GO framework membranes with a higher surface charge and lower transport resistance. The newly developed membrane exhibited a high pure water permeability of 5.01 L m(-2) h(-1) bar(-1) and comparably high rejections toward Mg(2+), Pb(2+), Ni(2+), Cd(2+), and Zn(2+). These results have demonstrated the great potential of GO framework materials in wastewater treatment and may provide insights for the design and fabrication of the next generation two-dimensional (2D)-based NF membranes.

  2. AFM study of the SIMS beam induced roughness in monocrystalline silicon in presence of initial surface or bulk defects of nanometric size

    Energy Technology Data Exchange (ETDEWEB)

    Fares, B. [Laboratoire de Physique de la Matiere (UMR CNRS 5511), INSA de Lyon, 7 Avenue Capelle, F-69621 Villeurbanne Cedex (France)]. E-mail: boubker.fares@insa-lyon.fr; Dubois, C. [Laboratoire de Physique de la Matiere (UMR CNRS 5511), INSA de Lyon, 7 Avenue Capelle, F-69621 Villeurbanne Cedex (France); Gautier, B. [Laboratoire de Physique de la Matiere (UMR CNRS 5511), INSA de Lyon, 7 Avenue Capelle, F-69621 Villeurbanne Cedex (France); Dupuy, J.C. [Laboratoire de Physique de la Matiere (UMR CNRS 5511), INSA de Lyon, 7 Avenue Capelle, F-69621 Villeurbanne Cedex (France); Cayrel, F. [Universite de Tours, Laboratoire de Micro-Electronique de Puissance, 16 Rue Pierre et Marie Curie, F-37071 Tours Cedex 2 (France); Gaudin, G. [Universite de Tours, Laboratoire de Micro-Electronique de Puissance, 16 Rue Pierre et Marie Curie, F-37071 Tours Cedex 2 (France)

    2006-07-30

    In this paper, the SIMS beam induced roughness (BIR) in monocrystalline Si in presence of initial surface or bulk defects of nanometric size is studied. We follow the development of the BIR by monitoring the increase of Si{sup 2+} and SiO{sub 2} {sup +} signals during SIMS sputtering. The topography of the crater bottoms is measured at different steps of the evolution of the roughness using an atomic force microscope (AFM). We show that in presence of nanometric sized defects on the surface or in the bulk, the BIR develops far more rapidly than usual. It appears as soon as the crater reaches the defects and, as reported on Si free from any treatment, the same morphology evidencing waves perpendicular to the sputtering beam develops rapidly. This study of the behaviour of the BIR in presence of voluntarily introduced defects allows us to better understand the basic physical phenomena involved in its apparition.

  3. Concept and architecture of a new apparatus for cylindrical form measurement with a nanometric level of accuracy

    Science.gov (United States)

    Vissiere, A.; Nouira, H.; Damak, M.; Gibaru, O.; David, J.-M.

    2012-09-01

    In relation to the industrial need and to the progress of technology, Laboratoire National de Métrologie et d’Essais (LNE) would like to improve the measurement of its primary pressure standards, spherical and flick standards. The spherical and flick standards are, respectively, used to calibrate the spindle motion error and the probe, which equip commercial conventional cylindricity-measuring machines. The primary pressure standards are obtained using pressure balances equipped with rotary pistons. To reach a relative uncertainty of 10-6 in the pressure measurement, it is necessary to know the diameters of both the piston and the cylinder with an uncertainty of 5 nm for a piston diameter of 10 mm. Conventional machines are not able to reach such an uncertainty level. That is why the development of a new machine is necessary. The purpose of this paper is to present the concepts and the architecture adopted in the development of the new equipment dedicated to cylindricity measurement at a nanometric level of a accuracy. The choice of these concepts is based on the analysis of the uncertainty sources encountered in conventional architectures. The architecture of the new ultra-high equipment as well as the associated calibration procedures will be described and detailed.

  4. Upgrading design of the 3B1A beamline for x-ray nanometre lithography of microelectronic devices at BSRF

    Institute of Scientific and Technical Information of China (English)

    Yi Fu-Ting; Ye Tian-Chun; Peng Liang-Qiang; Chen Da-Peng; Zhang Ju-Fang; Han Yong

    2004-01-01

    Beijing Synchrotron Radiation Facility is a partly dedicated synchrotron radiation source operated in either parasitic or dedicated mode. The 3B1A beamline, extracted from a bending magnet, was originally designed as a soft x-ray beamline for submicro x-ray lithography with critical lateral size just below 1μm in 1988 and no change has been made since it was built. But later the required resolution of x-ray lithography has changed from sub-micrometre to the nanometre in the critical lateral size. This beamline can longer more meet the requirement for x-ray nano lithography and has to be modified to fit the purpose. To upgrade the design of the 3B1A beamline for x-ray nano lithography, a mirror is used to reflect and scan the x-ray beam for the nano lithography station, but the mirror's grazing angle is changed to 27.9mrad in the vertical direction, and the convex curve needs to be modified to fit the change; the tiny change of mirror scanning angle is firstly considered to improve the uniformity of the x-ray spot on the wafer by controlling the convex curve.

  5. Study of nanometric thin pyrolytic carbon films for explosive electron emission cathode in high-voltage planar diode

    Energy Technology Data Exchange (ETDEWEB)

    Baryshevsky, Vladimir; Belous, Nikolai; Gurinovich, Alexandra; Gurnevich, Evgeny [Research Institute for Nuclear Problems, Belarusian State University, Bobruiskaya Str. 11, Minsk 220030 (Belarus); Kuzhir, Polina, E-mail: polina.kuzhir@gmail.com [Research Institute for Nuclear Problems, Belarusian State University, Bobruiskaya Str. 11, Minsk 220030 (Belarus); National Research Tomsk State University, 36 Lenin Prospekt, Tomsk 634050 (Russian Federation); Maksimenko, Sergey [Research Institute for Nuclear Problems, Belarusian State University, Bobruiskaya Str. 11, Minsk 220030 (Belarus); National Research Tomsk State University, 36 Lenin Prospekt, Tomsk 634050 (Russian Federation); Molchanov, Pavel; Shuba, Mikhail [Research Institute for Nuclear Problems, Belarusian State University, Bobruiskaya Str. 11, Minsk 220030 (Belarus); Roddatis, Vladimir [CIC energiGUNE, Albert Einstein 48, 01510 Minano, Alava (Spain); Institut für Materialphysik of Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany); Kaplas, Tommi; Svirko, Yuri [Institute of Photonics, University of Eastern Finland, P.O. Box 111, Joensuu FI-80101 (Finland)

    2015-04-30

    We report on an experimental study of explosive electron emission properties of cathode made by nanometric thin pyrolytic carbon (PyC) films (2–150 nm) deposited on Cu substrate via methane-based chemical vapor deposition. High current density at level of 300 A/cm{sup 2} in 5 · 10{sup −5} Pa vacuum has been observed together with very stable explosive emission from the planar cathode. The Raman spectroscopy investigation proves that the PyC films remain the same after seven shots. According to the optical image analysis of the cathode before and after one and seven shots, we conclude that the most unusual and interesting feature of using the PyC films/Cu cathode for explosive emission is that the PyC layer on the top of the copper target prevents its evaporation and oxidation, which leads to higher emission stability compared to conventional graphitic/Cu cathodes, and therefore results in longer working life. - Highlights: • Explosive electron emission from pyrolytic carbon (PyC) cathode is reported. • We observe high current density, 300 A/cm{sup 2}, and stable emission parameters. • PyC integrity ensures a high application potential for high current electronics.

  6. Nanometre-scale investigations by atomic force microscopy into the effect of different treatments on the surface structure of hair.

    Science.gov (United States)

    Durkan, C; Wang, N

    2014-12-01

    To investigate the effect of different washing regimes on the surface of human hair at the nanometre scale - comparable to the size of typical deposits left behind by commercial products. Atomic force microscopy (AFM) and related techniques. It can be directly seen that washing hair using commercial hair care products removes deposits that naturally form on the shaft, revealing the underlying structure of the hair, whereas in many cases leaving new deposits behind. The spatial distribution of these deposits is explored and quantified. The spatial distribution of the surface charge of pristine hair is mapped, and the electrical screening effect of deposits is directly observed. We also show that the roughness of the treated hair depends directly on the type of product used, with a marked difference between shampoo and conditioner. Some products leave isolated deposits behind, whereas others leave layers of material behind which wet the hair surface. Atomic force microscopy and the related techniques we have employed in a forensic approach is able to distinguish between different hair care products on the basis of the deposits they leave behind. This opens up the capability of further analysis tools to complement already existing techniques. © 2014 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  7. Synthesis of MWCNTs Using Monometallic and Bimetallic Combinations of Fe, Co and Ni Catalysts Supported on Nanometric SiC via TCVD

    Directory of Open Access Journals (Sweden)

    F. Shahi

    2015-04-01

    Full Text Available Nanometric Carbid Silicon (SiC supported monometallic and bimetallic catalysts containing Fe, Co, Ni transition metals were prepared by wet impregnation method. Multiwall carbon nanotubes (MWCNTs were synthesized over the prepared catalysts from catalytic decomposition of acetylene at 850°C by thermal chemical vapor deposition (TCVD technique. The synthesized nanomaterials (catalysts and CNTs were characterized by X-ray diffraction (XRD, Scanning Electron Microscopy (SEM, Transmission Electron Microscopy (TEM and Raman spectroscopy. In this paper, using of nanometric SiC powder as catalyst support was examined and the effect of applied catalyst type on characteristics of grown CNTs was investigated. The results revealed that iron, cobalt and nickel are in oxide, cobalt ferrite (CoFe2O4 and nickel ferrite (NiFe2O4 forms and nanometric SiC powder can be applied as an appropriate catalyst support in CNT growth process. It was observed that the produced CNTs on bimetallic Fe-Co possess smaller average diameter, less amorphous carbon and denser morphology compared to other binary metallic combinations. It was found that the catalytic activity of bimetallic composition decreased in the order of Fe-Co> Fe-Ni> Co-Ni. Furthermore, the monometallic Fe catalyst has the most catalytic activity compared to monometallic Co and Ni catalysts.

  8. Synthesis of New Silicon-linked Lanthanocene Complexes and Their High Catalytic Activity for Methyl Methacrylate Polymerization with Nanometric Sodium Hydride as Co-catalyst

    Institute of Scientific and Technical Information of China (English)

    谢小敏; 黄吉玲

    2005-01-01

    The synthesis and characterization of four new silicon-linked lanthanocene complexes with pendant phenyl groups on cyclopentadiene were reported. Based on the data of elemental analyses, MS and IR, the complexes were presumed to be unsolvated and dimeric complexes [Me2Si(C5H3CMe2C6H5)2LnC1]2 [Ln=Er (1), Gd (2), Sm (3), Dy (4)]. In conjunction with AlEt3 or sodium hydride as the co-catalyst, these complexes could efficiently catalyze the polymerization of methyl methacrylate (MMA). When the nanometric sodium hydride was used as a co-catalyst, the complexes were highly effective for the polymerization of MMA. At low temperature and in short time, in [MeESi(C5H3CMe2C6H5)2LnC1]2/NaH (nanometric) system, the polymer was obtained in more than 80% yield and the molecular weight was greater than 105. The activity reached that of organolanthanide hydride as a single-component catalyst. In ]MeESi(C5H3CMe2C6H5)2ErC1]2/Nail (nanometric) system, the effects of the molar ratio of MMA/catalyst and catalyst/co-catalyst, and the temperature on polymerization were studied.

  9. Stability of Menisci in Detached Bridgman Growth

    Science.gov (United States)

    Mazuruk, Konstantin; Volz, Martin P.

    2013-01-01

    Detached growth, also referred to as dewetted growth, is a Bridgman crystal growth process in which the melt is in contact with the crucible wall but the crystal is not. A meniscus bridges the gap between the top of the crystal and the crucible wall. The meniscus shape depends on the contact angle of the melt with the crucible wall, the growth angle of the melt with respect to the solidifying crystal, the gas pressure differential, the Weber number describing the rotation rate of the crucible, and the Bond number. Only some of the meniscus shapes are stable and the stability criterion is the sign of the second variation of the potential energy upon admissible meniscus shape perturbations. The effects of confined gas volumes above and below the melt and crucible rotation are evaluated. The analysis is applicable to the non-stationary case where the crystal radius changes during growth. Static stability maps (crystal radius versus pressure differential) are obtained for a series of Bond numbers, growth angles and Weber numbers. Also, the specific cases of Ge and InSb, in both terrestrial and microgravity conditions, are analyzed. Stability was found to depend significantly on whether the interior surface was considered to be microscopically rough or smooth, corresponding to pinned or unpinned states. It was also found that all meniscus shapes are statically stable in a microgravity environment.

  10. 基于SEM纳米切削装置的设计与实验%Design and Experiment on SEM Based Nanometric Cutting Device

    Institute of Scientific and Technical Information of China (English)

    刘冰; 徐宗伟; 兀伟; 王志强

    2015-01-01

    To solve the problem that online high-resolution observation failed to be realized in cutting process with the current nanometric cutting mechanism,a nanometric cutting device under high vacuum condition based on SEM was designed and established. Motion accuracy analysis of the device was carried out and nanometric cutting of typical single crystal materials with online observation was researched. The proposed device can realize displacement output in the range of 7 µm with closed-loop resolution of 0.6,nm in both cutting direction and depth direction. The motion accuracy of the device was measured by white light interferometer. Step structures with different cutting depths were machined and the height differences between the steps were 59.3 nm,115.1 nm and 161.2 nm,respectively. Nanometric cutting experiment was carried out on single-crystal copper and silicon by using diamond tool with straight edge. The experimental result indicates that the developed nanometric cutting device enables nanoscale mate-rial removal behavior to be achieved with online high-resolution observation.%针对目前纳米切削机理研究方法中切削过程无法在线高分辨力观测等瓶颈问题,设计并搭建了一套集成于扫描电子显微镜高真空条件下的纳米切削实验装置,开展了该实验装置的运动精度分析、典型单晶材料纳米切削在线观测等研究.该装置在切削及切深方向均能实现7,µm 的位移输出,闭环分辨力为0.6,nm.通过白光干涉仪对纳米切削台阶加工结果的测量,分析装置运动精度,实现了切深分别为59.3,nm、115.1,nm 和161.2,nm 的台阶结构加工.利用直线刃金刚石刀具对单晶铜和单晶硅材料进行了纳米切削实验,实验结果表明所研制的纳米切削装置能够实现纳米尺度材料去除的在线高分辨力观测.

  11. Shale gas characteristics of the Lower Toarcian Posidonia Shale in Germany: from basin to nanometre scale

    Science.gov (United States)

    Schulz, Hans-Martin; Bernard, Sylvain; Horsfield, Brian; Krüger, Martin; Littke, Ralf; di primio, Rolando

    2013-04-01

    The Early Toarcian Posidonia Shale is a proven hydrocarbon source rock which was deposited in a shallow epicontinental basin. In southern Germany, Tethyan warm-water influences from the south led to carbonate sedimentation, whereas cold-water influxes from the north controlled siliciclastic sedimentation in the northwestern parts of Germany and the Netherlands. Restricted sea-floor circulation and organic matter preservation are considered to be the consequence of an oceanic anoxic event. In contrast, non-marine conditions led to sedimentation of coarser grained sediments under progressively terrestrial conditions in northeastern Germany The present-day distribution of Posidonia Shale in northern Germany is restricted to the centres of rift basins that formed in the Late Jurassic (e.g., Lower Saxony Basin and Dogger Troughs like the West and East Holstein Troughs) as a result of erosion on the basin margins and bounding highs. The source rock characteristics are in part dependent on grain size as the Posidonia Shale in eastern Germany is referred to as a mixed to non-source rock facies. In the study area, the TOC content and the organic matter quality vary vertically and laterally, likely as a consequence of a rising sea level during the Toarcian. Here we present and compare data of whole Posidonia Shale sections, investigating these variations and highlighting the variability of Posidonia Shale depositional system. During all phases of burial, gas was generated in the Posidonia Shale. Low sedimentation rates led to diffusion of early diagenetically formed biogenic methane. Isochronously formed diagenetic carbonates tightened the matrix and increased brittleness. Thermogenic gas generation occurred in wide areas of Lower Saxony as well as in Schleswig Holstein. Biogenic methane gas can still be formed today in Posidonia Shale at shallow depth in areas which were covered by Pleistocene glaciers. Submicrometric interparticle pores predominate in immature samples. At

  12. Measurement of track structure parameters of low and medium energy helium and carbon ions in nanometric volumes

    Science.gov (United States)

    Hilgers, G.; Bug, M. U.; Rabus, H.

    2017-10-01

    Ionization cluster size distributions produced in the sensitive volume of an ion-counting wall-less nanodosimeter by monoenergetic carbon ions with energies between 45 MeV and 150 MeV were measured at the TANDEM-ALPI ion accelerator facility complex of the LNL-INFN in Legnaro. Those produced by monoenergetic helium ions with energies between 2 MeV and 20 MeV were measured at the accelerator facilities of PTB and with a 241Am alpha particle source. C3H8 was used as the target gas. The ionization cluster size distributions were measured in narrow beam geometry with the primary beam passing the target volume at specified distances from its centre, and in broad beam geometry with a fan-like primary beam. By applying a suitable drift time window, the effective size of the target volume was adjusted to match the size of a DNA segment. The measured data were compared with the results of simulations obtained with the PTB Monte Carlo code PTra. Before the comparison, the simulated cluster size distributions were corrected with respect to the background of additional ionizations produced in the transport system of the ionized target gas molecules. Measured and simulated characteristics of the particle track structure are in good agreement for both types of primary particles and for both types of the irradiation geometry. As the range in tissue of the ions investigated is within the typical extension of a spread-out Bragg peak, these data are useful for benchmarking not only ‘general purpose’ track structure simulation codes, but also treatment planning codes used in hadron therapy. Additionally, these data sets may serve as a data base for codes modelling the induction of radiation damages at the DNA-level as they almost completely characterize the ionization component of the nanometric track structure.

  13. Self-assembly of organic monolayers as protective and conductive bridges for nanometric surface-mount applications.

    Science.gov (United States)

    Platzman, Ilia; Haick, Hossam; Tannenbaum, Rina

    2010-09-01

    In this work, we present a novel surface-mount placement process that could potentially overcome the inadequacies of the currently used stencil-printing technology, when applied to devices in which either their lateral and/or their horizontal dimensions approach the nanometric scale. Our novel process is based on the "bottom-up" design of an adhesive layer, operative in the molecular/nanoscale level, through the use of self-assembled monolayers (SAMs) that could form protective and conductive bridges between pads and components. On the basis of previous results, 1,4-phenylene diisocyanide (PDI) and terephthalic acid (TPA) were chosen to serve as the best candidates for the achievement of this goal. The quality and stability of these SAMs on annealed Cu surfaces (Rrms=0.15-1.1 nm) were examined in detail. Measurements showed that the SAMs of TPA and PDI molecules formed on top of Cu substrates created thermally stable organic monolayers with high surface coverage (∼90%), in which the molecules were closely packed and well-ordered. Moreover, the molecules assumed a standing-up phase conformation, in which the molecules bonded to the Cu substrate through one terminal functional group, with the other terminal group residing away from the substrate. To examine the ability of these monolayers to serve as "molecular wires," i.e., the capability to provide electrical conductivity, we developed a novel fabrication method of a parallel plate junction (PPJ) in order to create symmetric Cu-SAM-Cu electrical junctions. The current-bias measurements of these junctions indicated high tunneling efficiency. These achievements imply that the SAMs used in this study can serve as conductive molecular bridges that can potentially bind circuital pads/components.

  14. Technical Note: Nanometric organic photovoltaic thin film detectors for dose monitoring in diagnostic x-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Elshahat, Bassem [Medical Physics Program, Department of Physics and Applied Physics, University of Massachusetts Lowell, Lowell, Massachusetts 01854 and Department of Medical Imaging, Royal Jubilee Hospital, Vancouver Island Health Authority, Victoria, British Columbia V8R 1J8 (Canada); Gill, Hardeep Singh; Kumar, Jayant [Department of Physics and Applied Physics, University of Massachusetts Lowell, Lowell, Massachusetts 01854 (United States); Filipyev, Ilya; Zygmanski, Piotr [Harvard Medical School, Dana Farber Cancer Institute and Brigham and Women’s Hospital, Boston, Massachusetts 02215 (United States); Shrestha, Suman; Karellas, Andrew [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States); Hesser, Jürgen [Department of Radiation Oncology, University Medical Center Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, Mannheim 68167 (Germany); Sajo, Erno [Medical Physics Program, Department of Physics and Applied Physics, University of Massachusetts Lowell, Lowell, Massachusetts 01854 (United States)

    2015-07-15

    Purpose: To fabricate organic photovoltaic (OPV) cells with nanometric active layers sensitive to ionizing radiation and measure their dosimetric characteristics in clinical x-ray beams in the diagnostic tube potential range of 60–150 kVp. Methods: Experiments were designed to optimize the detector’s x-ray response and find the best parameter combination by changing the active layer thickness and the area of the electrode. The OPV cell consisted of poly (3-hexylthiophene-2,5-diyl): [6,6]-phenyl C{sub 61} butyric acid methyl ester photoactive donor and acceptor semiconducting organic materials sandwiched between an aluminum electrode as an anode and an indium tin oxide electrode as a cathode. The authors measured the radiation-induced electric current at zero bias voltage in all fabricated OPV cells. Results: The net OPV current as a function of beam potential (kVp) was proportional to kVp{sup −0.5} when normalized to x-ray tube output, which varies with kVp. Of the tested configurations, the best combination of parameters was 270 nm active layer thicknesses with 0.7 cm{sup 2} electrode area, which provided the highest signal per electrode area. For this cell, the measured current ranged from approximately 0.7 to 2.4 nA/cm{sup 2} for 60–150 kVp, corresponding to about 0.09 nA–0.06 nA/mGy air kerma, respectively. When compared to commercial amorphous silicon thin film photovoltaic cells irradiated under the same conditions, this represents 2.5 times greater sensitivity. An additional 40% signal enhancement was observed when a 1 mm layer of plastic scintillator was attached to the cells’ beam-facing side. Conclusions: Since both OPVs can be produced as flexible devices and they do not require external bias voltage, they open the possibility for use as thin film in vivo detectors for dose monitoring in diagnostic x-ray imaging.

  15. SU-E-CAMPUS-I-01: Nanometric Organic Photovoltaic Thin Film X-Ray Detectors for Clinical KVp Beams

    Energy Technology Data Exchange (ETDEWEB)

    Elshahat, Bassem; Gill, Hardeep; Kumar, Jayant; Sajo, Erno [University of Massachusetts Lowell, Department of Physics and Applied Physics, Lowell, MA (United States); Filipyev, Ilya; Zygmanski, Piotr [Brigham and Women' s Hospital, Boston, MA (United States); Shrestha, Suman [Brigham and Women' s Hospital, Boston, MA (United States); University of Massachusetts Medical School, Worcester, MA (United States); Hesser, Jurgen [Department of Radiation Oncology, University Medical Center Mannheim (Germany); Karellas, Andrew [University of Massachusetts Medical School, Worcester, MA (United States)

    2014-06-15

    Purpose: To fabricate and test nanometric organic photovoltaic (OPV) cells made of various active-layer/electrode thicknesses and sizes; to determine the optimal material combinations and geometries suitable for dose measurements in clinical kilovoltage x-ray beams. Methods: The OPV consisted of P3HT:PCBM photoactive materials sandwiched between aluminum and Indium Tin Oxide (ITO) electrodes. Direct conversion of xrays in the active layer composed of donor and acceptor semiconducting organic materials generated signal in photovoltaic mode (without external voltage bias). OPV cells were fabricated with different active layer thicknesses (150, 270, 370 nm) and electrode areas (0.4, 0.7, 0.9, 1.4, 2.6 cm{sup 2}). A series of experiments were preformed in the energy range of 60–150 kVp. The net current per unit area (nA/cm{sup 2}) was measured using 200 mAs time-integrated beam current. Results: The net OPV current as function of beam energy (kVp) was proportional to ∼E{sup 0,4} {sup 5} when adjusted for beam output. The best combination of parameters for these cells was 270 nm active layer thicknesses for 0.7 cm{sup 2} electrode area. The measured current ranged from 0.69 to 2.43 nA/cm{sup 2} as a function of x-ray energy between 60 and 150 kVp, corresponding to 0.09 – 0.06 nA/cm{sup 2}/mGy, respectively, when adjusted for the beam output. Conclusion: The experiments indicate that OPV detectors possessing 270 nm active layer and 0.7 cm{sup 2} Al electrode areas have sensitivity by a factor of 2.5 greater than commercial aSi thin film PV. Because OPV can be made flexible and they do not require highvoltage bias supply, they open the possibility for using as in-vivo detectors in radiation safety in x-ray imaging beams.

  16. The use of atomic force microscopy as an important technique to analyze the dispersion of nanometric fillers and morphology in nanocomposites and polymer blends based on elastomers

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Fabiula Danielli Bastos de; Scuracchio, Carlos Henrique, E-mail: fabiuladesousa@gmail.com [Universidade Federal do ABC (CECS/UFABC), Santo Andre, SP (Brazil). Centro de Engenharia, Modelagem e Ciencias Sociais Aplicadas

    2014-11-15

    AFM has been recognized as one of the most powerful tools for the analysis of surface morphologies because it creates three-dimensional images at angstrom and nano scale. This technique has been exhaustively used in the analyses of dispersion of nanometric components in nanocomposites and in polymer blends, because of the easiness of sample preparation and lower equipment maintenance costs compared to electron microscopy. In this review, contributions using AFM are described, with emphasis on the dispersion of nanofillers in polymeric matrices. It is aimed to show the importance of technical analysis for nanocomposites and polymer blends based on elastomers. (author)

  17. Advanced Methods for Treatment of Organic Compounds Contamined Water

    Directory of Open Access Journals (Sweden)

    PREDESCU Andra

    2009-08-01

    Full Text Available The progress recorded in the field of science and advanced engineering at nanometric scale supplies largeopportunities for more efficient (from the point of view of the costs and more ecological approach of the processes ofwater purifying. This paper delivers a short description of the possibilities of using advanced materials in purifying thecontamined water with toxic metallic ions, organic and anorganic compounds. The opportunities and challenges werealso emphasized when nanomaterials were used for the surface, underground and industrial used waters treatment.

  18. Water

    Science.gov (United States)

    Leopold, Luna Bergere; Baldwin, Helene L.

    1962-01-01

    What do you use water for?If someone asked you this question you would probably think right away of water for drinking. Then you would think of water for bathing, brushing teeth, flushing the toilet. Your list would get longer as you thought of water for cooking, washing the dishes, running the garbage grinder. Water for lawn watering, for play pools, for swimming pools, for washing the car and the dog. Water for washing machines and for air conditioning. You can hardly do without water for fun and pleasure—water for swimming, boating, fishing, water-skiing, and skin diving. In school or the public library, you need water to wash your hands, or to have a drink. If your home or school bursts into flames, quantities of water are needed to put it out.In fact, life to Americans is unthinkable without large supplies of fresh, clean water. If you give the matter a little thought, you will realize that people in many countries, even in our own, may suffer from disease and dirt simply because their homes are not equipped with running water. Imagine your own town if for some reason - an explosion, perhaps - water service were cut off for a week or several weeks. You would have to drive or walk to a neighboring town and bring water back in pails. Certainly if people had to carry water themselves they might not be inclined to bathe very often; washing clothes would be a real chore.Nothing can live without water. The earth is covered by water over three-fourths of its surface - water as a liquid in rivers, lakes and oceans, and water as ice and snow on the tops of high mountains and in the polar regions. Only one-quarter of our bodies is bone and muscle; the other three-fourths is made of water. We need water to live, and so do plants and animals. People and animals can live a long time without food, but without water they die in a few days. Without water, everything would die, and the world would turn into a huge desert.

  19. Water

    Science.gov (United States)

    ... Lead Poisoning Prevention Training Center (HHLPPTC) Training Tracks Water Language: English Español (Spanish) Recommend on Facebook Tweet Share Compartir For information about lead in water in Flint, MI, please visit http://www.phe. ...

  20. Chemical Synthesis, Characterisation, and Biocompatibility of Nanometre Scale Porous Anodic Aluminium Oxide Membranes for Use as a Cell Culture Substrate for the Vero Cell Line: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Gérrard Eddy Jai Poinern

    2014-01-01

    Full Text Available In this preliminary study we investigate for the first time the biomedical potential of using porous anodic aluminium oxide (AAO membranes as a cell substrate for culturing the Cercopithecus aethiops (African green monkey Kidney (Vero epithelial cell line. One advantage of using the inorganic AAO membrane is the presence of nanometre scale pore channels that allow the exchange of molecules and nutrients across the membrane. The size of the pore channels can be preselected by adjusting the controlling parameters of a temperature controlled two-step anodization process. The cellular interaction and response of the Vero cell line with an in-house synthesised AAO membrane, a commercially available membrane, and a glass control were assessed by investigating cell adhesion, morphology, and proliferation over a 72 h period. The number of viable cells proliferating over the respective membrane surfaces revealed that the locally produced in-house AAO membrane had cells numbers similar to the glass control. The study revealed evidence of focal adhesion sites over the surface of the nanoporous membranes and the penetration of cellular extensions into the pore structure as well. The outcome of the study has revealed that nanometre scale porous AAO membranes have the potential to become practical cell culture scaffold substrates with the capability to enhance adhesion and proliferation of Vero cells.

  1. Investigating the role of microbes in mineral weathering: nanometre-scale characterisation of the cell-mineral interface using FIB and TEM.

    Science.gov (United States)

    Ward, Michael B; Kapitulčinová, Dana; Brown, Andrew P; Heard, Peter J; Cherns, David; Cockell, Charles S; Hallam, Keith R; Ragnarsdóttir, K Vala

    2013-04-01

    Focused ion beam (FIB) sample preparation in combination with subsequent transmission electron microscopy (TEM) analysis are powerful tools for nanometre-scale examination of the cell-mineral interface in bio-geological samples. In this study, we used FIB-TEM to investigate the interaction between a cyanobacterium (Hassallia byssoidea) and a common sheet silicate mineral (biotite) following a laboratory-based bioweathering, incubation experiment. We discuss the FIB preparation of cross-sections of the cell mineral interface for TEM investigation. We also establish an electron fluence threshold (at 200keV) in biotite for the transition from scanning (S)TEM electron beam induced contamination build up on the surface of biotite thin sections to mass loss, or hole-drilling within the sections. Working below this threshold fluence nanometre-scale structural and elemental information has been obtained from biotite directly underneath cyanobacterial cells incubated on the biotite for 3 months. No physical alteration of the biotite was detected by TEM imaging and diffraction with little or no elemental alteration detected by STEM-energy dispersive X-ray (EDX) elemental line-scanning or by energy filtered TEM (EF-TEM) jump ratio elemental mapping. As such we present evidence that the cyanobacterial strain of H. byssoidea did not cause any measurable alteration of biotite, within the resolution limits of the analysis techniques used, after 3 months of incubation on its surface.

  2. Chemical synthesis, characterisation, and biocompatibility of nanometre scale porous anodic aluminium oxide membranes for use as a cell culture substrate for the vero cell line: a preliminary study.

    Science.gov (United States)

    Poinern, Gérrard Eddy Jai; Le, Xuan Thi; O'Dea, Mark; Becker, Thomas; Fawcett, Derek

    2014-01-01

    In this preliminary study we investigate for the first time the biomedical potential of using porous anodic aluminium oxide (AAO) membranes as a cell substrate for culturing the Cercopithecus aethiops (African green monkey) Kidney (Vero) epithelial cell line. One advantage of using the inorganic AAO membrane is the presence of nanometre scale pore channels that allow the exchange of molecules and nutrients across the membrane. The size of the pore channels can be preselected by adjusting the controlling parameters of a temperature controlled two-step anodization process. The cellular interaction and response of the Vero cell line with an in-house synthesised AAO membrane, a commercially available membrane, and a glass control were assessed by investigating cell adhesion, morphology, and proliferation over a 72 h period. The number of viable cells proliferating over the respective membrane surfaces revealed that the locally produced in-house AAO membrane had cells numbers similar to the glass control. The study revealed evidence of focal adhesion sites over the surface of the nanoporous membranes and the penetration of cellular extensions into the pore structure as well. The outcome of the study has revealed that nanometre scale porous AAO membranes have the potential to become practical cell culture scaffold substrates with the capability to enhance adhesion and proliferation of Vero cells.

  3. Water

    CSIR Research Space (South Africa)

    Van Wyk, Llewellyn V

    2010-08-01

    Full Text Available Water scarcity is without a doubt on of the greatest threats to the human species and has all the potential to destabilise world peace. Falling water tables are a new phenomenon. Up until the development of steam and electric motors, deep groudwater...

  4. Water

    Directory of Open Access Journals (Sweden)

    E. Sanmuga Priya

    2017-05-01

    Full Text Available Phytoremediation through aquatic macrophytes treatment system (AMATS for the removal of pollutants and contaminants from various natural sources is a well established environmental protection technique. Water hyacinth (Eichhornia crassipes, a worst invasive aquatic weed has been utilised for various research activities over the last few decades. The biosorption capacity of the water hyacinth in minimising various contaminants present in the industrial wastewater is well studied. The present review quotes the literatures related to the biosorption capacity of the water hyacinth in reducing the concentration of dyestuffs, heavy metals and minimising certain other physiochemical parameters like TSS (total suspended solids, TDS (total dissolved solids, COD (chemical oxygen demand and BOD (biological oxygen demand in textile wastewater. Sorption kinetics through various models, factors influencing the biosorption capacity, and role of physical and chemical modifications in the water hyacinth are also discussed.

  5. Environmental benignity of a pesticide in soft colloidal hydrodispersive nanometric form with improved toxic precision towards the target organisms than non-target organisms.

    Science.gov (United States)

    Balaji, A P B; Sastry, Thotapalli P; Manigandan, Subramani; Mukherjee, Amitava; Chandrasekaran, Natarajan

    2017-02-01

    Mosquito-borne diseases are of major concern as they cause devastating health effects, morbidity, and mortality in the human population. Conventional pesticides have failed to curb the mosquito population due to the development of insensitivity in mosquitoes. Hence, higher dosages of pesticides along with their toxic solubilizers have been employed, which have led to raise in pesticide pollution load, environmental toxicity, and human health concerns. As a realisation for the requirement of alternative pesticides, the present study has involved in the formulation of a hydrodispersive nanometric colloidal form of deltamethrin (NDM), a type-II pyrethroid pesticide, from its hydroimmisicible parental form (PDM). The mean hydrodynamic diameter of the droplets was found to be 30.6±4.6nm by dynamic light scattering study (DLS). High-resolution transmission electron micrographs have revealed the spherical structure of the droplets with a size range of 35-40nm. The NDM was found to possess sedimentation resistance, intrinsic and hydrodispersive stability. The toxicity of NDM and PDM was comparatively investigated on target organisms (Culex tritaeniorhynchus and Culex quinquefasciatus mosquitoes) and non-target organisms (Allium cepa - Bioindicator of toxicants and Rhizobium sp. - Soil bacteria). As comparative to PDM, NDM has exerted higher efficacy on adult mosquito and larval population, even at low-level concentrations. However, in the case of non-target organisms, the NDM toxicity was lower than PDM. Comprehensively, the study has concluded the potential advantage of formulating conventional pesticides into nanometric soft colloidal form for the improved toxic precision on target organisms (mosquitoes). This ensures the ability of NDM to combat against the mosquito population even at lower concentrations, thereby reducing the pesticide exposure load towards the environment and human population.

  6. Thickness-dependent optical band gap in one-dimensional Ca{sub 3}Co{sub 2}O{sub 6} nanometric films

    Energy Technology Data Exchange (ETDEWEB)

    Moubah, Reda [Institut de Physique et Chimie des Materiaux de Strasbourg (IPCMS), UMR 7504 CNRS-UDS (UDS-ECPM), 23 rue du Loess, BP 43, F-67034 Strasbourg Cedex 2 (France); Colis, Silviu, E-mail: colis@ipcms.u-strasbg.fr [Institut de Physique et Chimie des Materiaux de Strasbourg (IPCMS), UMR 7504 CNRS-UDS (UDS-ECPM), 23 rue du Loess, BP 43, F-67034 Strasbourg Cedex 2 (France); Gallart, Mathieu; Schmerber, Guy; Gilliot, Pierre; Dinia, Aziz [Institut de Physique et Chimie des Materiaux de Strasbourg (IPCMS), UMR 7504 CNRS-UDS (UDS-ECPM), 23 rue du Loess, BP 43, F-67034 Strasbourg Cedex 2 (France)

    2012-02-15

    Recent studies on the physical properties of Ca{sub 3}Co{sub 2}O{sub 6} nanometric samples have shown that their properties are significantly different from those of the bulk samples. The origin of this change is not trivial. We have carried out optical measurements on Ca{sub 3}Co{sub 2}O{sub 6} thin films with different thicknesses in order to characterize their electronic structure using optical spectroscopy measurements. The absorption spectra show a dependence on the film thickness that is correlated to the grain size in the polycrystalline layers. We found that the optical band gap increases from 1.3 to 1.55 eV when the thickness changes from 35 to 100 nm. The change in the band gap evolution with the film thickness is discussed in terms of both the amorphous effect and the grain size in the Ca{sub 3}Co{sub 2}O{sub 6} thin films. Finally, we show that these results are consistent with recent measurements concerning magnetic and electrical properties of Ca{sub 3}Co{sub 2}O{sub 6} nanometric samples. - Highlights: Black-Right-Pointing-Pointer The optical properties of Ca{sub 3}Co{sub 2}O{sub 6} thin films were found dependent on the film thickness. Black-Right-Pointing-Pointer The band gap varies from 1.3 to 1.5 eV when the thickness increases from 35 to 100 nm. Black-Right-Pointing-Pointer The gap evolution is described in terms of grain size and amorphous effect. Black-Right-Pointing-Pointer This is similar to the variation of the magnetic properties with the film thickness. Black-Right-Pointing-Pointer Magnetic and optical properties have similar origins related to the particular structure.

  7. Water clustering on nanostructured iron oxide films

    DEFF Research Database (Denmark)

    Merte, Lindsay Richard; Bechstein, Ralf; Peng, G.;

    2014-01-01

    , but it is not well-understood how these hydroxyl groups and their distribution on a surface affect the molecular-scale structure at the interface. Here we report a study of water clustering on a moire-structured iron oxide thin film with a controlled density of hydroxyl groups. While large amorphous monolayer...... islands form on the bare film, the hydroxylated iron oxide film acts as a hydrophilic nanotemplate, causing the formation of a regular array of ice-like hexameric nanoclusters. The formation of this ordered phase is localized at the nanometre scale; with increasing water coverage, ordered and amorphous...

  8. Experimental Comparison of the Effects of Nanometric and Micrometric Particulates on the Tensile Properties and Fracture Behavior of Al Composites at Room and Elevated Temperatures

    Science.gov (United States)

    Ahmed, Adnan; Neely, Andrew J.; Shankar, Krishna

    2011-03-01

    This article studies the influence of nanometric (n-SiCp) and micrometric-scale SiC particulates ( μ-SiCp) on the tensile properties of the Al 7075 alloy. The unreinforced Al and its composites were synthesized using the powder metallurgy (P/M) route and were tested uniaxially in tension at both room and elevated temperatures. Aging behavior was studied to observe any effect of the reinforcement on the aging kinetics and hardness of the composites. X-ray diffraction was performed to determine the crystal structures of the raw materials and any reaction phase formed in the composites. The n-SiCp were not dispersed uniformly in the Al matrix and clustered mainly at the grain boundaries. The stiffness of the composites increased and the ductility decreased with an increase in the volume fraction of the n-SiCp. The n-SiCp proved to be a better reinforcement than the traditional μ-SiCp in terms of imparting higher ductility to the composite. Fractography and microscopy using optical, scanning electron, and transmission electron microscopes were performed for failure and microstructural analysis of all the materials. At room temperature, the fracture altered from ductile in the unreinforced Al to brittle in the composites. At an elevated temperature, the fracture mechanism transformed from brittle to ductile rupture in the composites.

  9. Electrical and electroluminescent characterization of nanometric multilayers of SiOX/SiOY obtained by LPCVD including non-normal emission

    Science.gov (United States)

    Alarcón-Salazar, J.; Zaldívar-Huerta, I. E.; Aceves-Mijares, M.

    2016-06-01

    This work describes the analysis and fabrication by Low Pressure Chemical Vapor Deposition of two light-emitting capacitors (LECs) constituted by nanometric multilayers of silicon-rich oxide. For both structures, seven layers were used: three light emitting layers with 6% silicon excess and four conductive layers with 12% silicon excess for one LEC and the other with 14% silicon excess. Both LECs were annealed at 1100 °C. Both multilayers demonstrate a substantially improved photoluminescent response compared to single emitting layers. A dielectric constant of 4.1 and a trap density of 1016 cm-3 were obtained from capacitance-voltage curves. Analysis of current-voltage and electroluminescence-voltage (EL-V) characteristics indicates that EL initiates under the space-charge-limited current mechanism, and the required voltage to turn on the emission is 38 V which is the trap-free limit voltage. However, EL increases exponentially under the impact ionization and trap-assisted tunneling conduction mechanisms. The electroluminescence spectra for both multilayers show two emission peaks centered in 450 and 700 nm attributed to oxygen defects. Also, the LEC non-normal emission was measured and it behaves like a Lambertian optical source. Both multilayers obtain the values of efficiency in the order of 10-6 which is in good agreement with the values reported in the literature.

  10. Adsorption and capillary condensation in porous media as a function of the chemical potential of water in carbon dioxide

    Science.gov (United States)

    Heath, Jason E.; Bryan, Charles R.; Matteo, Edward N.; Dewers, Thomas A.; Wang, Yifeng; Sallaberry, Cédric J.

    2014-03-01

    The chemical potential of water may play an important role in adsorption and capillary condensation of water under multiphase conditions at geologic CO2 storage sites. Injection of large volumes of anhydrous CO2 will result in changing values of the chemical potential of water in the supercritical CO2 phase. We hypothesize that the chemical potential will at first reflect the low concentration of dissolved water in the dry CO2. As formation water dissolves into and is transported by the CO2 phase, the chemical potential of water will increase. We present a pore-scale model of the CO2-water interface or menisci configuration based on the augmented Young-Laplace equation, which combines adsorption on flat surfaces and capillary condensation in wedge-shaped pores as a function of chemical potential of water. The results suggest that, at a given chemical potential for triangular and square pores, liquid water saturation will be less in the CO2-water system under potential CO2 sequestration conditions relative to the air-water vadose zone system. The difference derives from lower surface tension of the CO2-water system and thinner liquid water films, important at pore sizes capillary effects will likely be minimal in reservoir rocks, but still may be important in finer grained, clayey caprocks, where very small pores may retain water and draw water back into the system via adsorption and capillary condensation, if dry-out and then rewetting were to occur.

  11. 纳米钼酸盐阻燃剂的制备及表征%Preparation and Characterization of Nanometre Salt Molybdate Smoldering Agent

    Institute of Scientific and Technical Information of China (English)

    赵纯丽; 黄泽华; 李敏; 储召华

    2012-01-01

    The smoldering agent nanometre mognesium molybdate, calcium molybdate and barium molyb- date are systhesised by flux method. The crystal structure are determined by X - ray diffraction, the flame reatrdant effect of alkaline earth molybdate are compared by thermal weight and differental thermal analy- sis. The result show, the heat stability of calcium molybdate is poor, the losstemperature of magnesium mo- lybdate is higher 10 ℃ than calicium molybdate, over 50℃ than calcium molybdate;the decomposition process of maghesium molybdate is exothermic process, the and barium molybdate is endothermic prcess, the smoldering lybdate and calcium molybdate is order decline. decomposition process of calcium molybdate effect of maghesium molybdate, barium mo-%采用熔盐法合成了阻燃剂纳米钼酸镁、钼酸钙、钼酸钡。利用X射线衍射测定了其晶体结构,通过热重及差热分析比较了碱土金属钼酸盐的阻燃效果。结果表明,钼酸钙热稳定性较差,钼酸镁的失重温度比钼酸钙高约10℃,比钼酸钡高50℃以上;钼酸镁在分解过程中整体属于放热,钼酸钙、钼酸钡属于吸热过程,钼酸镁、钼酸钡和钼酸钙的阻燃效果依次递增。

  12. The physics of confined flow and its application to water leaks, water permeation and water nanoflows: a review.

    Science.gov (United States)

    Lei, Wenwen; Rigozzi, Michelle K; McKenzie, David R

    2016-02-01

    This review assesses the current state of understanding of the calculation of the rate of flow of gases, vapours and liquids confined in channels, in porous media and in permeable materials with an emphasis on the flow of water and its vapour. One motivation is to investigate the relation between the permeation rate of moisture and that of a noncondensable test gas such as helium, another is to assist in unifying theory and experiment across disparate fields. Available theories of single component ideal gas flows in channels of defined geometry (cylindrical, rectangular and elliptical) are described and their predictions compared with measurement over a wide range of conditions defined by the Knudsen number. Theory for two phase flows is assembled in order to understand the behaviour of four standard water leak configurations: vapour, slug, Washburn and liquid flow, distinguished by the number and location of phase boundaries (menisci). Air may or may not be present as a background gas. Slip length is an important parameter that greatly affects leak rates. Measurements of water vapour flows confirm that water vapour shows ideal gas behaviour. Results on carbon nanotubes show that smooth walls may lead to anomalously high slip lengths arising from the properties of 'confined' water. In porous media, behaviour can be matched to the four standard leaks. Traditional membrane permeation models consider that the permeant dissolves, diffuses and evaporates at the outlet side, ideas we align with those from channel flow. Recent results on graphite oxide membranes show examples where helium which does not permeate while at the same time moisture is almost unimpeded, again a result of confined water. We conclude that while there is no a priori relation between a noncondensable gas flow and a moisture flow, measurements using helium will give results within two orders of magnitude of the moisture flow rate, except in the case where there is anomalous slip or confined water

  13. 基于多尺度方法的单晶硅纳米切削%Study on nanometric cutting process of single crystal silicon based on multiscale method

    Institute of Scientific and Technical Information of China (English)

    朱朋哲; 房丰洲

    2012-01-01

    This paper features the development of Multiscale model of nanometric cutting of single crystal silicon by treating the critical region with MD(atomistic description) and capturing "far-field" elastic deformations using FE(continuum description).A HS region is used to couple the MD and FE regions.At the edge of HS region each description provides displacement boundary conditions for the other to realize the concurrent multiscale simulation.The investigation into Nanometric cutting process of single crystal silicon using the multiscale model shows that during nanometric cutting of single crystal silicon,the chip in front of the tool is formed by extrusion.Investigations of the distributions of atomic bond length,the variations of number of atoms with specified nearest number of neighbors,and the atomic configurations of MD region of the workpiece reveal that there occurs a phase transformation from four fold coordinated diamond cubic phase(α-Si) to the six fold coordinated β-Si during the nanometric cutting process,namely the conclusion that phase transformation is the dominant deformation mechanism of single crystal silicon during the nanometric cutting process.The study marked by the development of the multiscale model of nanometric cutting of single crystal silicon provides an effective tool for further exploring the microscale mechanisms of nanometic cutting.%通过在关键区域采用分子动力学(原子)描述、在远场弹性变形区域采用有限元(连续介质力学)描述建立了单晶硅纳米切削的多尺度模型。在边界区域,分子动力学和有限元互为彼此提供边界条件从而实现分子动力学区域和有限元区域的耦合。利用多尺度模型研究了单晶硅的纳米切削过程,结果表明纳米切削中工件以推挤的方式在刀具前方形成切屑。纳米切削中工件的原子键长分布、不同配位数的原子数变化和工件MD区域的原子构型的研究

  14. Nanometric alternating magnetic field generator.

    Science.gov (United States)

    Espejo, A P; Tejo, F; Vidal-Silva, N; Escrig, J

    2017-07-05

    In this work we introduce an alternating magnetic field generator in a cylindrical nanostructure. This field appears due to the rotation of a magnetic domain wall located at some position, generating a magnetic region that varies its direction of magnetization alternately, thus inducing an alternating magnetic flux in its vicinity. This phenomenon occurs due to the competition between a spin-polarized current and a magnetic field, which allows to control both the angular velocity and the pinning position of the domain wall. As proof of concept, we study the particular case of a diameter-modulated nanowire with a spin-polarized current along its axis and the demagnetizing field produced by its modulation. This inhomogeneous field allows one to control the angular velocity of the domain wall as a function of its position along the nanowire allowing frequencies in the GHz range to be achieved. This generator could be used in telecommunications for devices in the range of radiofrequencies or, following Faraday's induction law, could also induce an electromotive force and be used as a movable alternate voltage source in future nanodevices.

  15. 纳米载银抗菌粉体材料的制备工艺与性能%THE PROCESSING TECHNIQUES AND PROPERTIES OF NANOMETRE CARRYING SILVER ANTIBACTERIAL POWDER

    Institute of Scientific and Technical Information of China (English)

    刘维良

    2001-01-01

    The processing techmiques of nanonetre particles have been adopted in this test. Nanometre Zireonium phosphate carrying silver antibacterial powder have properties:It is small particle size, wide antibacterialpedigree,more efficient, no poisonous to people's health, perdurable and more stable in high temperature.%本研究采用纳米粒子制备技术,制成的纳米磷酸锆载银抗菌粉体材料,具有颗粒尺寸小、抗菌谱广、高效、无毒、持久和耐热性。

  16. Study of the electric properties of the nanometric interface La0,80Sr0,20MnO3 +/-delta-Y0,08Zr0,92O1,96

    Science.gov (United States)

    Touati, A.; Madani, A.; Hammou, A.; Boussetta, H.

    2006-11-01

    Conductivity of perovskite-type oxide LSM20 was measured in air for different temperatures (375-1273 degrees K) using the 4 point method. LSM20 was prepared by solid-state reaction starting from mixtures of La2O3, MnCO3, and SrCO3 and sintered at 1673 degrees K. The results show that conductivity obeys the following law: sigma = AT (3/2) exp(-(E-a/kT)), which is representative of an activated jump mechanism between Mn3+ and Mn4+ sites. The LSM20-n (nanometric)YZ8 interface was characterized by impedance spectroscopy. Symmetrical cells with two LSM20 electrodes were used. The electrolyte conductivity values are very close to those obtained with silver electrodes (Ag-nYZ8) showing that the electrolyte response is independent of the nature of the electrode material. The study of the electrode conductivity versus temperature shows an activation energy equal to 1.67 eV slightly lower than that observed by other authors. The nanometric grain size of the electrolyte could be at the origin of this difference. The variation of the electrode conductivity versus oxygen partial pressure is described by the following law sigma = sigma(0) Po-2(1/2), suggesting that the limiting step of the electrode reaction is the dissociative adsorption of O-2 on the electrode material.

  17. Existence and Stability of Menisci in Detached Bridgman Growth

    Science.gov (United States)

    Volz, M. P.; Mazuruk, K.

    2011-01-01

    Detached growth, also referred to as dewetted growth, is a Bridgman crystal growth process in which the melt is in contact with the crucible wall but the crystal is not. A meniscus bridges the gap between the top of the crystal and the crucible wall. The Young-Laplace capillary equation was used to calculate the crystal radii of detached states as a function of the pressure differential across the meniscus. The detached states depend on the contact angle of the melt with the crucible wall, the growth angle of the melt with respect to the solidifying crystal, and the Bond number. A static stability analysis was performed on the calculated detached states. The stability criterion was the sign of the second variation of the potential energy upon admissible meniscus shape perturbations. The conditions considered corresponded to the growth of Ge and InSb, in both terrestrial and microgravity conditions. Stability was found to depend significantly on whether the interior surface was considered to be microscopically rough or smooth, corresponding to pinned or unpinned states. It was also found that all meniscus shapes which are single-valued functions of the radius are statically stable in a microgravity environment.

  18. Size effects and charge transport in metals: Quantum theory of the resistivity of nanometric metallic structures arising from electron scattering by grain boundaries and by rough surfaces

    Science.gov (United States)

    Munoz, Raul C.; Arenas, Claudio

    2017-03-01

    1977; (iii) The current in the sample should be proportional to TN, the probability that an electron traverses N consecutive (disordered) grains found along a mean free path; MS assumed that TN = 1. We review unpublished details of a quantum transport theory based upon a model of diffusive transport and Kubo's linear response formalism recently published [Arenas et al., Appl. Surf. Sci. 329, 184 (2015)], which permits estimating the increase in resistivity of a metallic specimen (over the bulk resistivity) under the combined effects of electron scattering by phonons, impurities, disordered grain boundaries, and rough surfaces limiting the sample. We evaluate the predicting power of both the MS theory and of the new quantum model on samples where the temperature dependence of the resistivity has been measured between 4 K and 300 K, and where surface roughness and grain size distribution has been measured on each sample via independent experiments. We find that the quantum theory does exhibit a predicting power, whereas the predicting power of the MS model as well as the significance and reliability of its fitting parameters seems questionable. We explore the power of the new theory by comparing, for the first time, the resistivity predicted and measured on nanometric Cu wires of (approximately) rectangular cross section employed in building integrated circuits, based upon a quantum description of electron motion.

  19. Reconstructing fluid-flow events in Lower-Triassic sandstones of the eastern Paris Basin by elemental tracing and isotopic dating of nanometric illite crystals

    Science.gov (United States)

    Blaise, Thomas; Clauer, Norbert; Cathelineau, Michel; Boiron, Marie-Christine; Techer, Isabelle; Boulvais, Philippe

    2016-03-01

    Lower- to Middle-Triassic sandstones from eastern Paris Basin were buried to a maximum depth of 2500 m at a paleo-temperature of about 100 °C. They contain extensive amounts of authigenic platy and filamentous illite particles similar to those reported in reservoirs generally buried at 3000 to -5000 m and subjected to temperatures of 120 to -150 °C. To evaluate this unexpected occurrence, such sandstones were collected from drill cores between 1825 and 2000 m depth, and nanometric-sized sub-fractions were separated. The illite crystals were identified by XRD, observed by SEM and TEM, analyzed for their major, trace, rare-earth elements and oxygen isotope compositions, and dated by K-Ar and Rb-Sr. Illite particles display varied growth features in the rock pore-space and on authigenic quartz and adularia that they postdate. TEM-EDS crystal-chemical in situ data show that the illite lath/fiber and platelet morphologies correspond at least to two populations with varied interlayer charges: between 0.7 and 0.9 for the former and between 0.8 and 1.0 for the latter, the Fe/Fe + Mg ratio being higher in the platelets. Except for the deeper conglomerate, the PAAS-normalized REE patterns of the illite crystals are bell-shaped, enriched in middle REEs. Ca-carbonates and Ca-phosphates were detected together with illite in the separates. These soluble components yield 87Sr/86Sr ratios that are not strictly in chemical equilibrium with the illite crystals, suggesting successive fluids flows with different chemical compositions. The K-Ar data of finer <0.05 μm illite separates confirm two crystallization events at 179.4 ± 4.5 and 149.4 ± 2.5 Ma during the Early and Late Jurassic. The slightly coarser fractions contain also earlier crystallized or detrital K-bearing minerals characterized by lower δ18O values. The δ18O of the finest authigenic illite separates tends to decrease slightly with depth, from 18.2 (±0.2) to 16.3 (±0.2)‰, suggesting different but

  20. Pore-scale distribution of mucilage affecting water repellency in the rhizosphere

    Science.gov (United States)

    Benard, Pascal; Zarebanadkouki, Mohsen; Hedwig, Clemens; Holz, Maire; Ahmed, Mutez; Carminati, Andrea

    2017-04-01

    The hydraulic properties of the rhizosphere are altered by plants, fungi and microorganism. Plant roots release different compounds into the soil. One of these substances is mucilage, a gel which turns water repellent upon drying. We introduce a conceptual model of mucilage deposition during soil drying and its impact on the soil wettability. As the soil dries, water menisci recede and draw mucilage towards the contact region between particles where it is deposited. At high mucilage content, mucilage deposits expand into the open pore space and finally block water infiltration when a critical fraction of the pore space is blocked. To test this hypothesis, we mixed mucilage and particles of different grain size, we let them dry and measured the contact angle using the sessile drop method. Mucilage deposition was visualized by light microscopy imaging. Contact angle measurements showed a distinct threshold-like behavior with a sudden increase in apparent contact angle at high mucilage concentrations. Particle roughness induced a more uniform distribution of mucilage. The observed threshold corresponds to the concentration when mucilage deposition occupies a critical fraction of the pore space, as visualized with the microscope images. In conclusion, water repellency is critically affected by the distribution of mucilage on the pore-scale. This microscopic heterogeneity has to be taken into account in the description of macroscopic processes, like water infiltration or rewetting of water repellent soil.

  1. Multiscale simulation of nanometric cutting of single crystal Cu based on bridging domain method%基于桥域理论的Cu单晶纳米切削跨尺度仿真研究

    Institute of Scientific and Technical Information of China (English)

    梁迎春; 盆洪民; 白清顺; 卢礼华

    2011-01-01

    One of the significant methods of multiscale simulation named bridging domain method which is a mixed atomistic-continuum formulation is reviewed.The mode related to atomistic/continuum coupling is introduced.The coupled method with the treatment of the overlapping subdomain is discussed,in which different scaling parameters(weigh factors) are adopted to calculate the energy of the system in the overlapping subdomain and to constrain the atomic and the continuum displacements by the Lagrange multiplier method.A bridging domain model is set up to investigate the effect of cutting speed on chip and workpiece atom force distribution in the nanometric cutting of single crystal copper.Simulation results show the cutting deformation coefficient decreases and the workpiece atom force increases with the increase of cutting speed.In addition,the machined surface qualities at different cutting speeds are investigated.The multiscale model and simulation of nanometric cutting are accomplished based on the bridging domain method,which lays a theoretical foundation for exploring the trans-scale simulation of nanometric cutting.%桥域方法是一种典型的跨尺度仿真研究方法.基于桥域理论,本文分析了原子和连续介质耦合区域的处理问题,即在耦合区采用不同的权重计算系统的能量,通过Lagrange乘子法对原子和连续介质位移进行约束.采用桥域方法,建立了单晶Cu米纳切削的跨尺度仿真模型,获得了单晶Cu纳米切削的材料变形机理.同时,研究了不同切削速度对纳米切削过程和原子受力分布的影响,仿真结果表明:随着切削速度的提高,切削区原子所受的力值增大,切屑变形系数减小,已加工表面变质层厚度增加.本文基于桥域理论,实现了Cu单晶纳米切削跨尺度的建模和仿真,为探索纳米切削的跨尺度仿真研究提供理论基础.

  2. Subharmonic excitation in amplitude modulation atomic force microscopy in the presence of adsorbed water layers

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Sergio [Laboratory of Energy and Nanosciences, Masdar Institute of Science and Technology, P.O. BOX 54224, Abu Dhabi (United Arab Emirates); Barcons, Victor [Departament de Disseny i Programacio de Sistemes Electronics, UPC - Universitat Politecnica de Catalunya Av. Bases, 61, 08242 Manresa (Spain); Verdaguer, Albert [Centre d' Investigacio en Nanociencia i Nanotecnologia (CIN2) (CSIC-ICN), Esfera UAB, Campus de la UAB, Edifici CM-7, 08193-Bellaterra, Catalunya (Spain); Chiesa, Matteo [Laboratory of Energy and Nanosciences, Masdar Institute of Science and Technology, P.O. BOX 54224, Abu Dhabi (United Arab Emirates); Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307 (United States)

    2011-12-01

    In ambient conditions, nanometric water layers form on hydrophilic surfaces covering them and significantly changing their properties and characteristics. Here we report the excitation of subharmonics in amplitude modulation atomic force microscopy induced by intermittent water contacts. Our simulations show that there are several regimes of operation depending on whether there is perturbation of water layers. Single period orbitals, where subharmonics are never induced, follow only when the tip is either in permanent contact with the water layers or in pure noncontact where the water layers are never perturbed. When the water layers are perturbed subharmonic excitation increases with decreasing oscillation amplitude. We derive an analytical expression which establishes whether water perturbations compromise harmonic motion and show that the predictions are in agreement with numerical simulations. Empirical validation of our interpretation is provided by the observation of a range of values for apparent height of water layers when subharmonic excitation is predicted.

  3. Influence of temperature and dopant concentration on structural, morphological and optical properties of nanometric Ce1-xErxO2-δ (x = 0.05–0.20) as a pigment

    KAUST Repository

    Stojmenović, Marija

    2015-07-31

    Ceramic pigments based on cerium oxide were synthesized by self–propagating room temperature method and their color properties were assessed from the viewpoint of potential environmentally nontoxic pink pigments. Thermal stabilities of the pigments were examined at 600, 900 and 1200 ºC. According to X–ray powder diffraction and Raman spectroscopy results, all obtained pigments were single–phase solid solutions of cerium oxide, independent of the concentration of dopants. The X–ray analysis showed that the crystallites were of nanometric dimensions, as recorded and by transmission electron microscopy analysis. Color characteristics of solid solutions, which depended on concentracion erbium ions and calcination temperature, and their position in the chromaticity diagram were studied by ultraviolet–visible spectrophotometry, which confirmed potential application of environmentally friendly pigments of desired color. The color efficiency of pigments was also evaluated by colorimetric analysis.

  4. 纳米氢氧化铜的均匀沉淀法制备及低温热容%Preparation of Cu (OH)2 nanometric powders by homogeneous precipitation and their low temperature heat capacity

    Institute of Scientific and Technical Information of China (English)

    吴新明; 易求实; 吴金平; 谭志诚; 屈松生

    2001-01-01

    使用氨水溶解硫酸铜,加入氢氧化钡沉淀分离硫酸根,所得铜氨清液加热蒸氨得氢氧化铜超细沉淀.沉淀分别用氨水和无水乙醇洗涤,60℃干燥,放置干燥器中至恒重.XRD、TEM、IcP测定表明,其平均粒径尺寸为45 nm,粒度分布范围窄,纯度高.用高精密全自动量热仪在78~370 K温区测定了热容,拟合出热容随温度变化的多项式方程,并对此氨浸新工艺--均匀沉淀法和有关的热力学性质进行了讨论.%The Cu(OH) 2 nanometric powders were prepared by a new method of homogeneous precipitation.The CuSO4 was dissolved in ammonia and the SO42- was removed by adding Ba(OH)2. The filtrate was heatedto remove ammonia and the Cu(OH) 2 was homogeneously deposited. The deposition was washed by ammoniaand ethanol, and the product was dried at 60 ℃, and then put in a desiccator to keep constant weight. Thegained powders were examined by XRD, TEM and ICP techniques and the results show that the grain size ofCu(OH) 2 nanometric powders is 45 nm in average within a narrow distribution range, and the powders arehighly purified. The heat capacity of the powders was measured in the temperature range of 78 ~ 370 K, andthe polynomial equations expressing the change of heat capacity with temperature was fitted. The ammonialeach techniques and thermodynamic properties were discussed.

  5. Interaction of a Long Alkyl Chain Protic Ionic Liquid and Water

    CERN Document Server

    Bodo, Enrico; Capitani, Francesco; Gontrani, Lorenzo; Leonelli, Francesca; Postorino, Paolo

    2014-01-01

    A combined experimental/theoretical approach has been used to investigate the role of water in modifying the microscopic interactions characterizing the optical response of butyl-ammonium nitrate (BAN) water solutions. Raman spectra, dominated by the signal from the protic ionic liquid, were collected as a function of the water content, and the corresponding spatial organization of the ionic couples, as well as their local arrangement with water molecules, was studied exploiting classical molecular dynamics calculations. High quality spectroscopic data, combined with a careful analysis, revealed that water affects the vibrational spectrum BAN in solution: as the water concentration is increased, peaks assigned to stretching modes show a frequency hardening together with a shape narrowing, whereas the opposite behavior is observed for peaks assigned to bending modes. Calculation results clearly show a nanometric spatial organization of the ionic couples that is not destroyed on increasing the water content at ...

  6. Vortex magnetic structure in framboidal magnetite reveals existence of water droplets in an ancient asteroid.

    Science.gov (United States)

    Kimura, Yuki; Sato, Takeshi; Nakamura, Norihiro; Nozawa, Jun; Nakamura, Tomoki; Tsukamoto, Katsuo; Yamamoto, Kazuo

    2013-01-01

    The majority of water has vanished from modern meteorites, yet there remain signatures of water on ancient asteroids. How and when water disappeared from the asteroids is important, because the final fluid-concentrated chemical species played critical roles in the early evolution of organics and in the final minerals in meteorites. Here we show evidence of vestigial traces of water based on a nanometre-scale palaeomagnetic method, applying electron holography to the framboids in the Tagish Lake meteorite. The framboids are colloidal crystals composed of three-dimensionally ordered magnetite nanoparticles and therefore are only able to form against the repulsive force induced by the surface charge of the magnetite as a water droplet parches in microgravity. We demonstrate that the magnetites have a flux closure vortex structure, a unique magnetic configuration in nature that permits the formation of colloidal crystals just before exhaustion of water from a local system within a hydrous asteroid.

  7. Water Clustering on Nanostructured Iron Oxide Films

    Energy Technology Data Exchange (ETDEWEB)

    Merte, L. R.; Bechstein, Ralf; Peng, Guowen; Rieboldt, Felix; Farberow, Carrie A.; Zeuthen, Helene; Knudsen, Jan; Laegsgaard, E.; Wendt, Stefen; Mavrikakis, Manos; Besenbacher, Fleming

    2014-06-30

    The adhesion of water to solid surfaces is characterized by the tendency to balance competing molecule–molecule and molecule–surface interactions. Hydroxyl groups form strong hydrogen bonds to water molecules and are known to substantially influence the wetting behaviour of oxide surfaces, but it is not well-understood how these hydroxyl groups and their distribution on a surface affect the molecular-scale structure at the interface. Here we report a study of water clustering on a moire´-structured iron oxide thin film with a controlled density of hydroxyl groups. While large amorphous monolayer islands form on the are film, the hydroxylated iron oxide film acts as a hydrophilic nanotemplate, causing the formation of a regular array of ice-like hexameric nanoclusters. The formation of this ordered phase is localized at the nanometre scale; with increasing water coverage, ordered and amorphous water are found to coexist at adjacent hydroxylated and hydroxyl-free domains of the moire´ structure.

  8. Water clustering on nanostructured iron oxide films.

    Science.gov (United States)

    Merte, Lindsay R; Bechstein, Ralf; Peng, Guowen; Rieboldt, Felix; Farberow, Carrie A; Zeuthen, Helene; Knudsen, Jan; Lægsgaard, Erik; Wendt, Stefan; Mavrikakis, Manos; Besenbacher, Flemming

    2014-06-30

    The adhesion of water to solid surfaces is characterized by the tendency to balance competing molecule-molecule and molecule-surface interactions. Hydroxyl groups form strong hydrogen bonds to water molecules and are known to substantially influence the wetting behaviour of oxide surfaces, but it is not well-understood how these hydroxyl groups and their distribution on a surface affect the molecular-scale structure at the interface. Here we report a study of water clustering on a moiré-structured iron oxide thin film with a controlled density of hydroxyl groups. While large amorphous monolayer islands form on the bare film, the hydroxylated iron oxide film acts as a hydrophilic nanotemplate, causing the formation of a regular array of ice-like hexameric nanoclusters. The formation of this ordered phase is localized at the nanometre scale; with increasing water coverage, ordered and amorphous water are found to coexist at adjacent hydroxylated and hydroxyl-free domains of the moiré structure.

  9. Molecular scale track structure simulations in liquid water using the Geant4-DNA Monte-Carlo processes

    Energy Technology Data Exchange (ETDEWEB)

    Francis, Z., E-mail: ziad.francis@gmail.co [Institut de Radioprotection et de Surete Nucleaire, Laboratoire de Dosimetrie des Rayonnements Ionisants, BP 17, 92262 Fontenay-aux-Roses Cedex (France); Incerti, S. [Universite Bordeaux 1, CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux Gradignan, CENBG, Chemin du Solarium, BP120, 33175 Gradignan (France); Capra, R. [Via Niella 12, 17100 Savona (Italy); Mascialino, B. [Department of Medical Radiation Physics, Stockholm University, Box 260, 17176 Stockholm (Sweden); Montarou, G. [Laboratoire de Physique Corpusculaire, 24 avenue des Landais, 63177 Aubiere (France); Stepan, V. [Nuclear Physics Institute ASCR, Na Truhlarce 39/64, Praha 8 (Czech Republic); Villagrasa, C. [Institut de Radioprotection et de Surete Nucleaire, Laboratoire de Dosimetrie des Rayonnements Ionisants, BP 17, 92262 Fontenay-aux-Roses Cedex (France)

    2011-01-15

    This paper presents a study of energy deposits induced by ionising particles in liquid water at the molecular scale. Particles track structures were generated using the Geant4-DNA processes of the Geant4 Monte-Carlo toolkit. These processes cover electrons (0.025 eV-1 MeV), protons (1 keV-100 MeV), hydrogen atoms (1 keV-100 MeV) and alpha particles (10 keV-40 MeV) including their different charge states. Electron ranges and lineal energies for protons were calculated in nanometric and micrometric volumes.

  10. Desalination of water by vapor-phase transport through hydrophobic nanopores

    Science.gov (United States)

    Lee, Jongho; Karnik, Rohit

    2010-08-01

    We propose a new approach to desalination of water whereby a pressure difference across a vapor-trapping nanopore induces selective transport of water by isothermal evaporation and condensation across the pore. Transport of water through a nanopore with saline water on one side and pure water on the other side under a pressure difference was theoretically analyzed under the rarefied gas assumption using a probabilistic framework that accounts for diffuse scattering from the pore walls as well as reflection from the menisci. The analysis revealed that in addition to salinity, temperature, and pressure difference, the nanopore aspect ratio and the probability of condensation of a water molecule incident on a meniscus from the vapor phase, known as the condensation coefficient, are key determinants of flux. The effect of condensation coefficient on mass flux becomes critical when the aspect ratio is small. However, the mass flux becomes independent of the condensation coefficient as the pore aspect ratio increases, converging to the Knudsen flux for long nanopores. For design of a nanopore membrane that can trap vapor, a minimum aspect ratio is derived for which coalescence of the two interfaces on either side of the nanopore remains energetically unfavorable. Based on this design criterion, the analysis suggests that mass flux in the range of 20-70 g/m2 s may be feasible if the system is operated at temperatures in the range of 30-50 °C. The proposed approach further decouples transport properties from material properties of the membrane, which opens the possibility of engineering membranes with appropriate materials that may lead to reverse osmosis membranes with improved flux, better selectivity, and high chlorine resistance.

  11. Interaction of a long alkyl chain protic ionic liquid and water.

    Science.gov (United States)

    Bodo, Enrico; Mangialardo, Sara; Capitani, Francesco; Gontrani, Lorenzo; Leonelli, Francesca; Postorino, Paolo

    2014-05-28

    A combined experimental/theoretical approach has been used to investigate the role of water in modifying the microscopic interactions characterizing the optical response of 1-butyl-ammonium nitrate (BAN) water solutions. Raman spectra, dominated by the signal from the protic ionic liquid, were collected as a function of the water content, and the corresponding spatial organization of the ionic couples, as well as their local arrangement with water molecules, was studied exploiting classical molecular dynamics calculations. High quality spectroscopic data, combined with a careful analysis, revealed that water affects the vibrational spectrum BAN in solution: as the water concentration is increased, peaks assigned to stretching modes show a frequency hardening together with a shape narrowing, whereas the opposite behavior is observed for peaks assigned to bending modes. Calculation results clearly show a nanometric spatial organization of the ionic couples that is not destroyed on increasing the water content at least within an intermediate range. Our combined results show indeed that small water concentrations even increase the local order. Water molecules are located among ionic couples and are closer to the anion than the cation, as confirmed by the computation of the number of H-bonds which is greater for water-anion than for water-cation. The whole results set thus clarifies the microscopic scenario of the BAN-water interaction and underlines the main role of the extended hydrogen bond network among water molecules and nitrate anions.

  12. Water, Water Everywhere

    Science.gov (United States)

    Keeler, Rusty

    2009-01-01

    Everybody knows that children love water and how great water play is for children. The author discusses ways to add water to one's playscape that fully comply with health and safety regulations and are still fun for children. He stresses the importance of creating water play that provides children with the opportunity to interact with water.

  13. Water, Water Everywhere

    Science.gov (United States)

    Keeler, Rusty

    2009-01-01

    Everybody knows that children love water and how great water play is for children. The author discusses ways to add water to one's playscape that fully comply with health and safety regulations and are still fun for children. He stresses the importance of creating water play that provides children with the opportunity to interact with water.

  14. Magnetic characterization of some nanometric iron oxides

    Energy Technology Data Exchange (ETDEWEB)

    Grecu, V. V., E-mail: vvgrecu@gmail.com [University of Bucharest, Physics Faculty (Romania); Constantinescu, S.; Grecu, Maria Nicoleta [National Institute for Materials Physics (Romania); Olar, Rodica; Badea, Mihaela [University of Bucharet, Chemistry Faculty (Romania); Turcu, Rodica [National Institute for Isotopic and Molecular Technologies (Romania)

    2008-04-15

    Nanosized magnetite particles embedded in polypyrrole matrix have been studied by Moessbauer and electron magnetic resonance spectroscopy. Comparison with as grown magnetite is made. Hyperfine fields distribution is determined and line shape of resonance curves are discussed in terms of composite structure, sizes and treatments.

  15. Nanometrization of Lanthanide-Based Coordination Polymers.

    Science.gov (United States)

    Neaime, Chrystelle; Daiguebonne, Carole; Calvez, Guillaume; Freslon, Stéphane; Bernot, Kevin; Grasset, Fabien; Cordier, Stéphane; Guillou, Olivier

    2015-11-23

    Heteronuclear lanthanide-based coordination polymers are microcrystalline powders, the luminescence properties of which can be precisely tuned by judicious choice of the rare-earth ions. In this study, we demonstrate that such materials can also be obtained as stable solutions of nanoparticles in non-toxic polyols. Bulk powders of the formula [Ln2-2x Ln'2x (bdc)3 ⋅4 H2 O]∞ (where H2 bdc denotes 1,4-benzene-dicarboxylic acid, 0≤x≤1, and Ln and Ln' denote lanthanide ions of the series La to Tm plus Y) afford nanoparticles that have been characterized by dynamic light-scattering (DLS) and transmission electron microscopy (TEM) measurements. Their luminescence properties are similar to those of the bulk materials. Stabilities versus time and versus dilution with another solvent have been studied. This study has revealed that it is possible to tune the size of the nanoparticles. This process offers a reliable means of synthesizing suspensions of nanoparticles with tunable luminescence properties and tunable size distributions in a green solvent (glycerol). The process is also extendable to other coordination polymers and other solvents (ethylene glycol, for example). It constitutes a new route for the facile solubilization of lanthanide-based coordination polymers.

  16. Effect of Tool Geometry in Nanometric Cutting

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    With the development of science and technology, the ultra-precision manufacturing of the brittle and hard materials with superior quality have become a new attractive subject. Brittle materials (such as engineering ceramics, optical glass, semiconductor and so on) are widely used in electronics, optics, aeronautics and other high technology fields, so there are important theory significance and practical value to systematically study its machining mechanism and technology. Single crystal silicon is one of t...

  17. Experimental study and mechanical modelling of the effects of water-driving in an oil saturated chalk. Application to the petroleum industry; Etude experimentale et modelisation mecanique des effets du balayage a l'eau dans une craie saturee d'huile. Application a l'industrie petroliere

    Energy Technology Data Exchange (ETDEWEB)

    Mata, C.

    2001-01-01

    The production of hydrocarbons may sometimes lead to compaction of the oil-reservoir layers with substantial collapse of the soil surface; this mechanism is usually mentioned as Subsidence. Classical remedy to this problem is to sustain the fluid pressure with the help of water injection. However, in presence of high porosity chalk (porosity > 30%), this technique does not give effective results: the subsidence rate at North Sea reservoirs (Ekofisk field), after injection, has remained unchanged. Some justify the subsistence in the chalk as caused by phenomena of dissolution of the carbonates; others think it is connected to the destruction of capillary menisci. In this research, we follow this second approach. This study is finalized to a better understanding of the compaction mechanisms in pure carbonates when water is injected. This is done by proposing -in micro-scale first and in macro-scale after- a physical model that agrees with empirical observations. In order to meet this target, IFP skills and experience in physical and chemical measurements (taken before, after and during mechanical tests) have proficiently joined ENPC laboratory (CERMMO) knowledge of micro and macro modelling. The soft rock studied is a Paris basin's white chalk (Craie de Guerville). Its physical and chemical characterisation (i.e.: silica content, porosity, permeability) is very similar to North Sea chalk, but Guerville chalk has never been in contact with oil and generally it crops out of the ground surface. Strength parameters of this rock have been first determined by standard triaxial tests. Three different saturation configurations have been examined: dry, fully oil-saturated and fully water-saturated. As literature clearly state, dry chalk is stronger than oil saturated chalk and the first two are largely stronger than water saturated chalk. Therefore uniaxial strain water injection tests have been performed on oil saturated samples. Results, coupled with previous physical

  18. Quantifying the flow dynamics of supercritical CO2-water displacement in a 2D porous micromodel using fluorescent microscopy and microscopic PIV

    Science.gov (United States)

    Kazemifar, Farzan; Blois, Gianluca; Kyritsis, Dimitrios C.; Christensen, Kenneth T.

    2016-09-01

    The multi-phase flow of liquid/supercritical CO2 and water (non-wetting and wetting phases, respectively) in a two-dimensional silicon micromodel was investigated at reservoir conditions (80 bar, 24 °C and 40 °C). The fluorescent microscopy and microscopic particle image velocimetry (micro-PIV) techniques were combined to quantify the flow dynamics associated with displacement of water by CO2 (drainage) in the porous matrix. To this end, water was seeded with fluorescent tracer particles, CO2 was tagged with a fluorescent dye and each phase was imaged independently using spectral separation in conjunction with microscopic imaging. This approach allowed simultaneous measurement of the spatially-resolved instantaneous velocity field in the water and quantification of the spatial configuration of the two fluid phases. The results, acquired with sufficient time resolution to follow the dynamic progression of both phases, provide a comprehensive picture of the flow physics during the migration of the CO2 front, the temporal evolution of individual menisci, and the growth of fingers within the porous microstructure. During that growth process, velocity jumps 20-25 times larger in magnitude than the bulk velocity were measured in the water phase and these bursts of water flow occurred both in-line with and against the bulk flow direction. These unsteady velocity events support the notion of pressure bursts and Haines jumps during pore drainage events as previously reported in the literature [1-3]. After passage of the CO2 front, shear-induced flow was detected in the trapped water ganglia in the form of circulation zones near the CO2-water interfaces as well as in the thin water films wetting the surfaces of the silicon micromodel. To our knowledge, the results presented herein represent the first quantitative spatially and temporally resolved velocity-field measurements at high pressure for water displacement by liquid/supercritical CO2 injection in a porous micromodel.

  19. Interplay between hydrophilicity and surface barriers on water transport in zeolite membranes

    Science.gov (United States)

    Fasano, Matteo; Humplik, Thomas; Bevilacqua, Alessio; Tsapatsis, Michael; Chiavazzo, Eliodoro; Wang, Evelyn N.; Asinari, Pietro

    2016-10-01

    A comprehensive understanding of molecular transport within nanoporous materials remains elusive in a broad variety of engineering and biomedical applications. Here, experiments and atomistic simulations are synergically used to elucidate the non-trivial interplay between nanopore hydrophilicity and surface barriers on the overall water transport through zeolite crystals. At these nanometre-length scales, these results highlight the dominating effect of surface imperfections with reduced permeability on the overall water transport. A simple diffusion resistance model is shown to be sufficient to capture the effects of both intracrystalline and surface diffusion resistances, thus properly linking simulation to experimental evidence. This work suggests that future experimental work should focus on eliminating/overcoming these surface imperfections, which promise an order of magnitude improvement in permeability.

  20. Determining the Most Appropriate Classification Methods for Water Quality

    Science.gov (United States)

    Gürsoy, Önder

    2016-10-01

    Assessing water resources’ quality and also monitoring them have attracted lots of attention in the recent years. Remote sensing has been growing widely in the last decade and its resources are very usable when it comes to water resources management. In this study, by using remote sensing technology, satellite images that have 350 to 1050 nanometres wavelength band sensors are used to determine the quality of the Kizilirmak River's water. Through the river's resources, ground based spectral measurements are made to identify the quality differences of the water at the test spots that have been determined before. In this context at Imranli, where the river contacts civilization for the first time, which is located in Sivas city of Turkey, samples are gathered in order to do ground based spectroradiometer measurements. These samples are gathered simultaneously with the image acquiring time of CHRIS Proba satellite. Spectral signatures that are obtained from ground measurements are used as reference data in order to classify CHRIS Proba satellite's hyperspectral images over the study area. Satellite images are classified based on Chemical Oxygen Demand (COD), Turbidity and Electrical Conductivity (EC) attributes. As a result, interpretations obtained from classified CHRIS Proba satellite hyperspectral images of the study area are presented. Spectras are readied for Matched Filtering and Spectral Angle Mapper methods for determining the best classification method.

  1. Water Contamination

    Science.gov (United States)

    ... Statistics Training & Education Policy & Recommendations Fast Facts Healthy Water Sites Healthy Water Drinking Water Healthy Swimming Global ... type=”submit” value=”Submit” /> Healthy Water Home Water Contamination Recommend on Facebook Tweet Share Compartir On ...

  2. Drinking Water

    Science.gov (United States)

    ... the safest water supplies in the world, but drinking water quality can vary from place to place. It ... water supplier must give you annual reports on drinking water. The reports include where your water came from ...

  3. Lorentz transmission electron microscopy on nanometric magnetic bubbles and skyrmions in bilayered manganites La{sub 1.2}Sr{sub 1.8}(Mn{sub 1−y}Ru{sub y}){sub 2}O{sub 7} with controlled magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Morikawa, D.; Yu, X. Z.; Kaneko, Y. [RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan); Tokunaga, Y.; Arima, T. [RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan); Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561 (Japan); Nagai, T.; Kimoto, K. [Transmission Electron Microscopy Station and Surface Physics and Structure Unit, National Institute for Materials Science (NIMS), Tsukuba 305-0044 (Japan); Tokura, Y. [RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan); Department of Applied Physics, University of Tokyo, Tokyo 113-8656 (Japan)

    2015-11-23

    We have investigated nanometric magnetic textures in thin (<150 nm) plates of Ru-doped bilayered manganites La{sub 1.2}Sr{sub 1.8}(Mn{sub 1−y}Ru{sub y}){sub 2}O{sub 7}. Ru substitution for Mn site changes the magnetic anisotropy from in-plane to out-of-plane easy axis type without any significant change of global magnetic and crystal structures. The combination of conventional and Lorentz transmission electron microscopy observations confirms the emergence of magnetic bubbles and skyrmions in the absence of magnetic field. With the changing Ru concentration, systematic changes in the type of magnetic bubbles are observed. A tiny residual magnetic field also affects the generation and the type-change of magnetic bubbles.

  4. Water desalination using nanoporous single-layer graphene.

    Science.gov (United States)

    Surwade, Sumedh P; Smirnov, Sergei N; Vlassiouk, Ivan V; Unocic, Raymond R; Veith, Gabriel M; Dai, Sheng; Mahurin, Shannon M

    2015-05-01

    By creating nanoscale pores in a layer of graphene, it could be used as an effective separation membrane due to its chemical and mechanical stability, its flexibility and, most importantly, its one-atom thickness. Theoretical studies have indicated that the performance of such membranes should be superior to state-of-the-art polymer-based filtration membranes, and experimental studies have recently begun to explore their potential. Here, we show that single-layer porous graphene can be used as a desalination membrane. Nanometre-sized pores are created in a graphene monolayer using an oxygen plasma etching process, which allows the size of the pores to be tuned. The resulting membranes exhibit a salt rejection rate of nearly 100% and rapid water transport. In particular, water fluxes of up to 10(6) g m(-2) s(-1) at 40 °C were measured using pressure difference as a driving force, while water fluxes measured using osmotic pressure as a driving force did not exceed 70 g m(-2) s(-1) atm(-1).

  5. Water desalination using nanoporous single-layer graphene

    Science.gov (United States)

    Surwade, Sumedh P.; Smirnov, Sergei N.; Vlassiouk, Ivan V.; Unocic, Raymond R.; Veith, Gabriel M.; Dai, Sheng; Mahurin, Shannon M.

    2015-05-01

    By creating nanoscale pores in a layer of graphene, it could be used as an effective separation membrane due to its chemical and mechanical stability, its flexibility and, most importantly, its one-atom thickness. Theoretical studies have indicated that the performance of such membranes should be superior to state-of-the-art polymer-based filtration membranes, and experimental studies have recently begun to explore their potential. Here, we show that single-layer porous graphene can be used as a desalination membrane. Nanometre-sized pores are created in a graphene monolayer using an oxygen plasma etching process, which allows the size of the pores to be tuned. The resulting membranes exhibit a salt rejection rate of nearly 100% and rapid water transport. In particular, water fluxes of up to 106 g m-2 s-1 at 40 °C were measured using pressure difference as a driving force, while water fluxes measured using osmotic pressure as a driving force did not exceed 70 g m-2 s-1 atm-1.

  6. Friction and Wear Behaviors of Nano-Silicates in Water

    Institute of Scientific and Technical Information of China (English)

    Chen Boshui; Lou Fang; Fang Jianhua; Wang Jiu; Li Jia

    2009-01-01

    Nano-metric magnesium silicate and zinc silicate with particle size of about 50--70nm were prepared in water by the method of chemical deposition. The antiwear and friction reducing abilities of the nano-silicates, as well as their compos-ites with oleie acid tri-ethanolamine (OATEA), were evaluated on a four-ball friction tester. The topographies and tribochemical features of the worn surfaces were analyzed by scanning electron microscope (SEM) and X-ray photoelectron spectroscope (XPS). Results show that nano-silicates alone provide poor antiwear and friction reducing abilities in water, but exhibits excellent synergism with OATEA in reducing friction and wear. The synergism in reducing friction and wear between naao-silicates and OATEA does exist almost regardless of particle sizes and species, and may be attributed, on one hand, to the formation of an adsorption film of OATEA, and, on the other hand, to the formation oftdbochemical species of silicon dioxide and iron oxides on the friction surfaces. Tribo-reactions and tribo-adsorptions of nano-silicates and OATEA would produce hereby an effective composite boondary lubrication film, which could efficiently enhance the anti-wear and friction-reducing abilities of water.

  7. Self-limiting and complete oxidation of silicon nanostructures produced by laser ablation in water

    Science.gov (United States)

    Vaccaro, L.; Popescu, R.; Messina, F.; Camarda, P.; Schneider, R.; Gerthsen, D.; Gelardi, F. M.; Cannas, M.

    2016-07-01

    Oxidized Silicon nanomaterials produced by 1064 nm pulsed laser ablation in deionized water are investigated. High-resolution transmission electron microscopy coupled with energy dispersive X-ray spectroscopy allows to characterize the structural and chemical properties at a sub-nanometric scale. This analysis clarifies that laser ablation induces both self-limiting and complete oxidation processes which produce polycrystalline Si surrounded by a layer of SiO2 and amorphous fully oxidized SiO2, respectively. These nanostructures exhibit a composite luminescence spectrum which is investigated by time-resolved spectroscopy with a tunable laser excitation. The origin of the observed luminescence bands agrees with the two structural typologies: Si nanocrystals emit a μs-decaying red band; defects of SiO2 give rise to a ns-decaying UV band and two overlapping blue bands with lifetime in the ns and ms timescale.

  8. Porous graphene-based membranes for water purification from metal ions at low differential pressures.

    Science.gov (United States)

    Park, Jaewoo; Bazylewski, Paul; Fanchini, Giovanni

    2016-05-14

    A new generation of membranes for water purification based on weakly oxidized and nanoporous few-layer graphene is here introduced. These membranes dramatically decrease the high energy requirements of water purification by reverse osmosis. They combine the advantages of porous and non-oxidized single-layer graphene, offering energy-efficient water filtration at relatively low differential pressures, and highly oxidized graphene oxide, exhibiting high performance in terms of impurity adsorption. In the reported fabrication process, leaks between juxtaposed few-layer graphene flakes are sealed by thermally annealed colloidal silica, in a treatment that precedes the opening of (sub)nanometre-size pores in graphene. This process, explored for the first time in this work, results in nanoporous graphene flakes that are water-tight at the edges without occluding the (sub)nanopores. With this method, removal of impurities from water occurs through a combination of size-based pore rejection and pore-edge adsorption. Thinness of graphene flakes allows these membranes to achieve water purification from metal ions in concentrations of few parts-per-million at differential pressures as low as 30 kPa, outperforming existing graphene or graphene oxide purification systems with comparable flow rates.

  9. Energy deposition in small-scale targets of liquid water using the very low energy electromagnetic physics processes of the Geant4 toolkit

    Science.gov (United States)

    Incerti, S.; Champion, C.; Tran, H. N.; Karamitros, M.; Bernal, M.; Francis, Z.; Ivanchenko, V.; Mantero, A.; Members of Geant4-DNA Collaboration

    2013-07-01

    In the perspective of building an open source simulation platform dedicated to the modelling of early biological molecular damages due to ionising radiation at the DNA scale, the general-purpose Geant4 Monte Carlo simulation toolkit has been recently extended with specific very low energy electromagnetic physics processes for liquid water medium. These processes - also called “Geant4-DNA” processes - simulate the physical interactions induced by electrons, hydrogen and helium atoms of different charge states. The present work reports on the energy deposit distributions obtained for incident electrons, protons and alpha particles in nanometre-size volumes comparable to those present in the genetic material of mammalian cells. The frequency distributions of the energy deposition obtained for three typical geometries of nanometre-size cylindrical targets placed in a spherical phantom are found to be in reasonable agreement with prior works. Furthermore, we present a combination of the Geant4-DNA processes with a simplified geometrical model of a cellular nucleus allowing the evaluation of energy deposits in volumes of biological interest.

  10. DIAGNOSTIC ACCURACY OF CLINICAL AND MAGNETIC RESONANCE IN KNEE MENISCI AND LIGAMENTOUS INJURIES

    Directory of Open Access Journals (Sweden)

    Nilesh

    2016-03-01

    Full Text Available OBJECTIVE The purpose of this study was to evaluate the reliability of clinical diagnosis compared to MRI findings in ligamentous and meniscal injuries with respect to arthroscopic confirmation as a gold standard. METHODS 485 patients with knee injuries were prospectively assessed by clinical evaluation and magnetic resonance imaging and correlated after therapeutic arthroscopy. The overall accuracy, clinically productive values of sensitivity and specificity was derived. The actual value of the test with respect to positive predictive and negative predictive value was also derived, taking arthroscopic findings as confirmatory. The overall partial and total agreement among the clinical, MRI and arthroscopy was documented. RESULTS The overall accuracy for clinical examination was 85, 92, 100 and 100 and accuracy for MRI was 90, 97, 97 and 97 for detecting medial meniscus, lateral meniscus, ACL and PCL tears respectively. Clinically lateral meniscus tears are difficult to diagnose clinically with negative predictive value (90 whereas ACL injuries do not need MRI for diagnosis as evident by a high negative predictive value (100 of clinical examination. Total agreement with the clinical findings confirmed by arthroscopy was 64.40% which was relatively high as compared to total agreement of MRI findings which was only 31.50%. We found similar total agreement versus total disagreement of both clinical and MRI to be only 2.74% indicating very high accuracy in clinical diagnosis of meniscal and ligamentous injuries combined. CONCLUSION The clinical evaluation alone is sufficient to diagnose meniscal and ACL/PCL pathologies and MRI should be considered only as a powerful negative diagnostic tool. The arthroscopy decision should not be heavily dependent on MRI for ligamentous injuries but reverse is true for meniscal lesions. MR evaluation functions as a powerful negative diagnostic tool to rule out doubtful and complex knee injuries.

  11. Use of a Precision Mercury Manometer with Capacitance Sensing of the Menisci

    Science.gov (United States)

    Jäger, J.

    1994-01-01

    A commercially available dual-cistern mercury manometer, modified in some details, has been in use for many years as the main standard instrument of the PTB for the pressure range up to 200 kPa (absolute and gauge). With this instrument the PTB participated in an international intercomparison of pressure standards in the barometric range, organized under the auspices of the Comité Consultatif pour la Masse et les grandeurs apparentées (CCM). An error analysis for absolute pressure measurements with the manometer is presented together with a discussion of experimental data and some technical details.

  12. Water citizenship

    DEFF Research Database (Denmark)

    Paerregaard, Karsten; Stensrud, Astrid Bredholt; Andersen, Astrid Oberborbeck

    2016-01-01

    This article examines the implementation of Peru’s new water law and discusses how it produces new forms of water citizenship. Inspired by the global paradigm of “integrated water resources management,” the law aims to include all citizens in the management of the country’s water resources...... by embracing a “new water culture.” We ask what forms of water citizenship emerge from the new water law and how they engage with local water practices and affect existing relations of inequality. We answer these questions ethnographically by comparing previous water legislation and how the new law currently...... is negotiated and contested in three localities in Peru’s southern highlands. We argue that the law creates a new water culture that views water as a substance that is measurable, quantifiable, and taxable, but that it neglects other ways of valuing water. We conclude that water citizenship emerges from...

  13. Water, Water Everywhere, But...

    Science.gov (United States)

    Jacobson, Cliff

    Materials for teaching a unit on water pollution are provided in this teaching package. These materials include: (1) a student reading booklet; (2) a reference booklet listing a variety of popular chemical, biological, and physical tests which can be performed on a local waterway and providing information about the environmental effects and toxic…

  14. Water, Water Everywhere, But...

    Science.gov (United States)

    Jacobson, Cliff

    Materials for teaching a unit on water pollution are provided in this teaching package. These materials include: (1) a student reading booklet; (2) a reference booklet listing a variety of popular chemical, biological, and physical tests which can be performed on a local waterway and providing information about the environmental effects and toxic…

  15. Healthy Water

    Science.gov (United States)

    ... Topics Newsroom, Features, & Announcements CDC at Work: Healthy Water Fast Facts WASH-related Observances Top Causes of Drinking ... Features, & Announcements Training & Education CDC at Work: Healthy Water Policy & Recommendations Fast Facts Index of Water-Related Topics By A- ...

  16. Parasites: Water

    Science.gov (United States)

    ... Tropical Diseases Laboratory Diagnostic Assistance [DPDx] Parasites Home Water Language: English Español (Spanish) Recommend on Facebook Tweet Share Compartir Parasites can live in natural water sources. When outdoors, treat your water before drinking ...

  17. Water Safety

    Science.gov (United States)

    ... Old Feeding Your 1- to 2-Year-Old Water Safety KidsHealth > For Parents > Water Safety Print A ... best measure of protection. previous continue Making Kids Water Wise It's important to teach your kids proper ...

  18. Water pollution

    OpenAIRE

    Institute, Marine

    2013-01-01

    Students will learn about what causes water pollution and how to be environmentally aware. *Note: Students should understand the concept of the water cycle before moving onto water pollution (see Lesson Plan “Oceans all Around Us”).

  19. Water conservation

    CSIR Research Space (South Africa)

    Gibberd, Jeremy T

    2009-02-01

    Full Text Available of their water needs from rainwater harvesting. • Water quality: The quality of water is matched with use. For instance, the best quality water may be used for drinking and cooking and poorer quality water, such as grey water, used for flushing toilets... and irrigation. • Onsite retention: In natural environments vegetation and soil absorb and retain a large proportion of rain water that falls on to it. Green buildings aim to emulate this by ensuring that buildings and sites absorb and retain rain water...

  20. Effect of C-C b ond breakage on diamond to ol wear in nanometric cutting of silicon%单晶硅纳米切削中C-C键断裂对金刚石刀具磨损的影响∗

    Institute of Scientific and Technical Information of China (English)

    王治国; 张鹏; 陈家轩; 白清顺; 梁迎春

    2015-01-01

    It is well known that diamond is one of the most ideal cutting tool for materials, but the rapid tool wear can make surface integrity of the machined surface decline sharply during the nanometric cutting process for a single crystal silicon. Thus, a research on the wear mechanism of the diamond tool is of tremendous importance for selecting measures to reduce tool wear so as to extend service life of the tool. In this paper, the molecular dynamics simulation is applied to investigating the wear of the diamond tool during nanometric cutting for the single crystal silicon. Tersoff potential is used to describe the C—C and Si—Si interactions, and also the Morse potential for the C—Si interaction. The rake and flank faces are diamond (111) and (¯1¯12) planes respectively. A new method, by the name of 6-ring, is proposed to describe the bond change of carbon atoms. This new method can extract, all the worn carbon atoms in diamond tool, whose accuracy is higher than the conventional coordination number method. Moreover, the graphitized carbon atoms in the diamond tool also can be extracted by the combination of these two methods. Results show that during the cutting process, the C—C bond’s breaking in the surface layer of the diamond tool leads to the transformation of hybrid structure of the carbon atoms at both ends of the broken bond, from sp3 to sp2. Following to the bond breaking, the bond angle between the surface carbon atoms increases to 119.3◦ whose hybrid structure has changed, and the length between nearest neighboring atoms quickly decreases to 0.144 nm, indicating that the space structure formed by these carbon atoms has changed from 3D net structure of diamond to plane structure of graphite. Hence, the carbon atoms in the tool surface whose space structure has changed due to bond breaking should be defined as worn carbon atoms, but not only the carbon atoms whose hybrid structure has changed. The structure defects at both edges of the diamond

  1. Water uptake and water supply

    NARCIS (Netherlands)

    Sonneveld, C.; Voogt, W.

    2009-01-01

    The water uptake and the water supply do not directly affect the mineral absorption of plants. However, many connections exist between the management of minerals and water. The most evident of those connections are following

  2. Water, mineral waters and health.

    Science.gov (United States)

    Petraccia, Luisa; Liberati, Giovanna; Masciullo, Stefano Giuseppe; Grassi, Marcello; Fraioli, Antonio

    2006-06-01

    The authors focus on water resources and the use of mineral waters in human nutrition, especially in the different stages of life, in physical activity and in the presence of some morbid conditions. Mineral water is characterized by its purity at source, its content in minerals, trace elements and other constituents, its conservation and its healing properties recognized by the Ministry of Health after clinical and pharmacological trials. Based on total salt content in grams after evaporation of 1l mineral water dried at 180 degrees C (dry residues), mineral waters can be classified as: waters with a very low mineral content, waters low in mineral content, waters with a medium mineral content, and strongly mineralized waters. Based on ion composition mineral waters can be classified as: bicarbonate waters, sulfate waters, sodium chloride or saltwater, sulfuric waters. Based on biological activity mineral waters can be classified as: diuretic waters, cathartic waters, waters with antiphlogistic properties. Instructions for use, doses, and current regulations are included.

  3. Modification of the stability of polymorph nanometric TiO{sub 2} by surface excess of SnO{sub 2}; Modificacao da estabilidade dos polimorfos de TiO{sub 2} nanometrico pelo excesso de superficie de SnO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Matioli, A.; Miagava, J.; Gouvea, D., E-mail: dgouvea@usp.br [Laboratorio de Processos Ceramicos, Departamento de Engenharia Metalurgica e de Materiais, Escola Politecnica da Universidade de Sao Paulo, SP (Brazil)

    2012-01-15

    Some oxides present stable polymorph forms only for nanometric size. Anatase (TiO{sub 2}) is stable in nanosized particles while the rutile phase is stable for larger ones. This results from the surface energies contribution, which modifies the total energy of the system and the phase stability. In turn, surface energy can be altered by the heterogeneous additives distribution, such as surface segregation or surface excess. This study investigated the action of the SnO{sub 2} on the polymorph stability of nanosized TiO{sub 2} prepared by polymeric precursor derived from the Pechini method. It appears that there is a strong effect on the stability of anatase and rutile with the SnO{sub 2} concentration while various surface properties are altered as well as a strong change in particle size, indicating that even though there are no large differences in the charge and size between the two cations, a surface phenomenon may underlie the stability of crystalline phases (author)

  4. Water Reuse: Using Reclaimed Water For Irrigation

    OpenAIRE

    Haering, Kathryn C.; Evanylo, Gregory K.; Benham, Brian Leslie, 1960-; Goatley, Michael

    2009-01-01

    Describes water reuse and reclaimed water, explains how reclaimed water is produced, options for water reuse, water reuse regulations, and agronomic concerns with water reuse, and provides several case studies of water reuse.

  5. Wasted waters.

    Science.gov (United States)

    Niemczynowicz, J

    1996-11-01

    This article presents the increasing mismanagement of water as a result of increasing delivery of water volume, water pollution, and water wasting. One example of water mismanagement is irrigation, through which 67% of water is withdrawn from the hydrological cycle. In addition, reports from European communities reveal that pesticides from agriculture worsen the existing underground pollution. Furthermore, a 25% drop in land productivity was observed in Africa due to erosion, salinization, water logging, and desertification. Also, 23% of withdrawn water goes to industries, which are the major polluters. Since 1900 about 250,000 tons of cadmium have been produced worldwide, which eventually enter and harm the aquatic and terrestrial ecosystems. Moreover, high mercury levels were observed in Malaysia's Kelang River in the late 1980s, and river pollution in Thailand and Malaysia is recorded to be 30-100 times higher than accepted levels. Aside from that, the human race must also understand that there is a connection between water scarcity and water quality. When there is water pollution, it is expected that many people will suffer diarrheal diseases and intestinal parasite infections, which will further increase the mortality rate to 3.3 million per year. Realizing the severity of the problem, it is suggested that the human race must learn to recycle water like stormwater to prevent scarcity with drinking water.

  6. Branding water.

    Science.gov (United States)

    Dolnicar, Sara; Hurlimann, Anna; Grün, Bettina

    2014-06-15

    Branding is a key strategy widely used in commercial marketing to make products more attractive to consumers. With the exception of bottled water, branding has largely not been adopted in the water context although public acceptance is critical to the implementation of water augmentation projects. Based on responses from 6247 study participants collected between 2009 and 2012, this study shows that (1) different kinds of water - specifically recycled water, desalinated water, tap water and rainwater from personal rainwater tanks - are each perceived very differently by the public, (2) external events out of the control of water managers, such as serious droughts or floods, had a minimal effect on people's perceptions of water, (3) perceptions of water were stable over time, and (4) certain water attributes are anticipated to be more effective to use in public communication campaigns aiming at increasing public acceptance for drinking purposes. The results from this study can be used by a diverse range of water stakeholders to increase public acceptance and adoption of water from alternative sources. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Water Pollution

    Science.gov (United States)

    Bowen, H. J. M.

    1975-01-01

    Deals with water pollution in the following categories: a global view, self purification, local pollution, difficulties in chemical analysis, and remedies for water pollution. Emphasizes the extent to which man's activities have modified the cycles of certain elements. (GS)

  8. Water Pollution

    Science.gov (United States)

    Bowen, H. J. M.

    1975-01-01

    Deals with water pollution in the following categories: a global view, self purification, local pollution, difficulties in chemical analysis, and remedies for water pollution. Emphasizes the extent to which man's activities have modified the cycles of certain elements. (GS)

  9. Water quality

    Science.gov (United States)

    Aquatic animals are healthiest and grow best when environmental conditions are within certain ranges that define, for a particular species, “good” water quality. From the outset, successful aquaculture requires a high-quality water supply. Water quality in aquaculture systems also deteriorates as an...

  10. Water Ways

    Science.gov (United States)

    Jahrling, Peter

    2007-01-01

    In many communities, schools are among the largest facilities and house the highest concentrations of daytime population. They create a huge demand for water. Even in regions with abundant water supplies, an increase in demand stresses local capacity, and water becomes more expensive. However, with the help of innovative products that reduce water…

  11. Water SA

    African Journals Online (AJOL)

    Journal Home > Vol 43, No 2 (2017) ... WaterSA publishes refereed, original work in all branches of water science, technology and engineering. ... Water SA is the WRC's accredited scientific journal which contains original research articles ... via linearized calibration method in the upstream of Huaihe River Basin, China ...

  12. A novel strategy to produce highly stable and transparent aqueous 'nanosolutions' of water-insoluble drug molecules

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jiexin; Zhang Zhibing; Le Yuan; Chen Jianfeng [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Zhao Hong, E-mail: chenjf@mail.buct.edu.cn [Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029 (China)

    2011-07-29

    A surprisingly large proportion of new drug candidates emerging from drug discovery programmes are water-insoluble and, as a result, have poor oral bioavailability. To overcome insolubility, the drug particles are usually dispersed in a medium during product formation, but large particles that are formed may affect product performance and safety. Many techniques have been used to produce nanodispersions-dispersions with nanometre-scale dimensions-that have properties similar to solutions. However, making nanodispersions requires complex processing, and it is difficult to achieve stability over long periods. In this paper, we report a generic method for preparing drug nanoparticles with a combination of antisolvent precipitation in the presence of water-soluble matrices and spray-drying. The spray-dried powder composites (solid dispersion) are microspherical, highly stable and thus form transparent nanodispersions or so-called 'nanosolutions' of water-insoluble drug when simply added to water. Aqueous nanodispersions of silybin (a kind of water-insoluble drug for liver protection) with an average size of 25 nm produced with this approach display a 10 times faster dissolution rate than that of raw drug. This has great potential to offer a novel solution for innovative drugs of the future.

  13. Droplet evaporation of pure water and protein solution on nanostructured superhydrophobic surfaces of varying heights.

    Science.gov (United States)

    Choi, Chang-Hwan; Kim, Chang-Jin C J

    2009-07-07

    Evaporation of liquids on substrates is important for many applications including lab-on-a-chip, especially when they are in droplets. Unlike on planar substrates, droplet evaporation on micropatterned substrates has been studied only recently and none so far on nanopatterns. Driven by the applicability of nanostructured surfaces to biomaterials and tissue engineering, we report on the evaporative process of sessile droplets of pure water and a protein solution on superhydrophobic surfaces of sharp-tip post structures in a submicrometer pitch (230 nm) and varying heights (100-500 nm). We find that the nanotopographical three-dimensionalities such as structural height and sidewall profile affect the surface superhydrophobicity in such a way that only tall and slender nanostructures provide the surface with great superhydrophobicity (a contact angle more than 170 degrees). The evaporation process was different between the pure water and the protein solution; unlike pure water, a significant contact-line spreading and pinning effect was observed in a droplet of a protein solution with an intermediate transition from a dewetting (Cassie) to a wetting (Wenzel) state. Enabled by well-defined nanostructures, our results highlight that the surface superhydrophobicity and the droplet evaporation are significantly affected by the three-dimensional nanometric topography and the surface fouling such as protein adsorption.

  14. Water-Quality Data

    Science.gov (United States)

    ... Water Quality? [1.7MB PDF] Past featured science... Water Quality Data Today's Water Conditions Get continuous real- ... list of USGS water-quality data resources . USGS Water Science Areas Water Resources Groundwater Surface Water Water ...

  15. Reversible Exsolution of Nanometric Fe2O3 Particles in BaFe2-x(PO4)2 (0 ≤ x ≤ 2/3):The Logic of Vacancy Ordering in Novel Metal-Depleted Two-Dimensional Lattices

    Energy Technology Data Exchange (ETDEWEB)

    Alcover, Ignacio Blazquez; David, Rénald; Daviero-Minaud, Sylvie; Filimonov, Dmitry; Huvé, Marielle; Roussel, Pascal; Kabbour, Houria; Mentré, Olivier [CNRS-UMR

    2015-08-12

    We show here that the exsolution of Fe2+ ions out of two-dimensional (2D) honeycomb layers of BaFe2(PO4)2 into iron-deficient BaFe2–x(PO4)2 phases and nanometric α-Fe2O3 (typically 50 nm diameter at the grain surface) is efficient and reversible until x = 2/3 in mild oxidizing/reducing conditions. It corresponds to the renewable conversion of 12 wt % of the initial mass into iron oxide. After analyzing single crystal X-ray diffraction data of intermediate members x = 2/7, x = 1/3, x = 1/2 and the ultimate Fe-depleted x = 2/3 term, we then observed a systematic full ordering between Fe ions and vacancies (VFe) that denote unprecedented easy in-plane metal diffusion driven by the Fe2+/Fe3+ redox. Besides the discovery of a diversity of original depleted triangular {Fe2/3+2–xO6} topologies, we propose a unified model correlating the x Fe-removal and the experimental Fe/VFe ordering into periodic one-dimensional motifs paving the layers, gaining insights into predictive crystahemistry of complex low dimensional oxides. When we increased the x values it led to a progressive change of the materials from 2D ferromagnets (Fe2+) to 2D ferrimagnets (Fe2/3+) to antiferromagnets for x = 2/3 (Fe3+).

  16. 纳米ZnO-SiO2自清洁增透薄膜的制备及其性能∗%Preparation and characterization of self-cleaning and anti-reflection ZnO-SiO2 nanometric films

    Institute of Scientific and Technical Information of China (English)

    郭昭龙; 赵海新; 赵卫

    2016-01-01

    Unlike the general anti-reflection and self-cleaning film such as SiO2 and TiO2-SiO2, the ZnO-SiO2 nanometric film used as a substrate of excellent transparency in visible region and effective photo-catalytic self-cleaning under UV illumination is seldom studied in the application as a substrate; however, it has a lot of advantages including high transmittance and low refractivity. In this paper, a self-cleaning and anti-reflection ZnO-SiO2 nanometric film is successfully fabricated by using a sol-gel dip-coating method. The morphology, crystal structure, surface microstructure and light transmittance of the obtained products are characterized by techniques such as TEM, SAD, XRD, SEM, DTA and UV-vis. Photo-catalytic degradation of the methylene blue (MB) in aqueous solution is used as probe reaction to evaluate the photo-catalytic activity of ZnO-SiO2 nanometric film. The TEM images reveal that the as-prepared ZnO nanoparticles are spherical grains with diameters of 12–20 nm, the average grain diameter is about 14.51 nm. ZnO nanoparticles obtained are of hexagonal wurtzite structure revealed by XRD pattern and there exist no other diffraction peaks. Furthermore, the SAD results show that ZnO microstructurs have good crystallinity. In addition, the ZnO grain size is about 14.41 nm by using the Scherrer formula calculation, which is consistent with the TEM results by the Gauss simulation. The UV-vis spectra reveal that the ultraviolet characteristic absorption peak of ZnO-SiO2 composite films is located at 368 nm and 375 nm after annealing at different temperatures such as 300 ◦C and 450 ◦C, corresponding to the band gaps of 3.37 eV and 3.31 eV, respectively. It is highly consistent with that obtained from pure ZnO nanoparticles. Increasing the annealing temperature results in a lower refractive index and the increases of the porosity in of the ZnO-SiO2 composite films. It has a uniformly refractive index value about 1.23–1.25 and a high porosity value about

  17. Fast Water

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Beijing’s Water Cube tailor made for swimming success The water in the Water Cube pool is tranquil now. The predatory power of American Michael Phelps churning his way to an unprecedented eighth gold medal in the men’s 4x100 meters medley relay, took swimming to new heights. And there is no doubt that Beijing’s bubbleshaped aquatics center helped in the process of the 21 new world swimming records.

  18. Supercritical water

    CERN Document Server

    Marcus, Yizhak

    2012-01-01

    Discover the many new and emerging applications of supercritical water as a green solvent Drawing from thousands of original research articles, this book reviews and summarizes what is currently known about the properties and uses of supercritical water. In particular, it focuses on new and emerging applications of supercritical water as a green solvent, including the catalytic conversion of biomass into fuels and the oxidation of hazardous materials. Supercritical Water begins with an introduction that defines supercritical fluids in general. It then defines supercritical wa

  19. Preparation of improved catalytic materials for water purification

    Science.gov (United States)

    Cherkezova-Zheleva, Z.; Paneva, D.; Tsvetkov, M.; Kunev, B.; Milanova, M.; Petrov, N.; Mitov, I.

    2014-04-01

    The aim of presented paper was to study preparation of catalytic materials for water purification. Iron oxide (Fe3O4) samples supported on activated carbon were prepared by wet impregnation method and low temperature heating in an inert atmosphere. The as-prepared, activated and samples after catalytic test were characterized by Mössbauer spectroscopy and X-ray diffraction. The obtained X-ray diffraction patterns of prepared samples show broad and low-intensity peaks of magnetite phase and the characteristic peaks of the activated carbon. The average crystallite size of magnetite particles was calculated below 20 nm. The registered Mössbauer spectra of prepared materials show a superposition of doublet lines or doublet and sextet components. The calculated hyperfine parameters after spectra evaluation reveal the presence of magnetite phase with nanosize particles. Relaxation phenomena were registered in both cases, i.e. superparamagnetism or collective magnetic excitation behavior, respectively. Low temperature Mössbauer spectra confirm this observation. Application of materials as photo-Fenton catalysts for organic pollutions degradation was studied. It was obtained high adsorption degree of dye, extremely high reaction rate and fast dye degradation. Photocatalytic behaviour of a more active sample was enhanced using mechanochemical activation (MCA). The nanometric size and high dispersion of photocatalyst particles influence both the adsorption and degradation mechanism of reaction. The results showed that all studied photocatalysts effectively decompose the organic pollutants under UV light irradiation. Partial oxidation of samples after catalytic tests was registered. Combination of magnetic particles with high photocatalytic activity meets both the requirements of photocatalytic degradation of water contaminants and that of recovery for cyclic utilization of material.

  20. Water tower

    CERN Multimedia

    1970-01-01

    The water tower, being built on the highest point of the site, 460.5 m above the sea level. The tank will hold 750 m3 of water, and the tower will be topped by a knob which can serve as a geological survey reference mark.

  1. Water Pollution

    Science.gov (United States)

    We all need clean water. People need it to grow crops and to operate factories, and for drinking and recreation. Fish and wildlife depend on ... and phosphorus make algae grow and can turn water green. Bacteria, often from sewage spills, can pollute ...

  2. WATER WARNINGS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    As the country's water supply goes down the drain, conservation and wastewater recycling have become urgent tasks for China At a news briefing ahead of the World Water Congress and Exhibition in Beijing, scheduled to begin September 10, Acting Chairman of the Organizing Committee and Vice Minister of Construction Qiu Baoxing delivered a statement that cut to the heart of the problem:

  3. Water futures

    DEFF Research Database (Denmark)

    Rasmussen, Mattias Borg

    2016-01-01

    This article explores the potential construction of a water reservoir in Peru’s Cordillera Blanca. Proposed by a peasant group, it would have served important productive purposes but have its intake within the perimeter of a national park. Thus, different notions about water and landscape emerge...... in the encounters between place-based practices and state-sponsored conservation efforts. Empirically tracing the efforts to construct the reservoir, the analytical focus of the article is on how different ways of knowing water within a particular landscape conjure and collide in the process. It is argued...... that the movement of water extends itself beyond the physical properties of the reservoir and irrigation channels as these are produced in encounters between different notions of the role of water in the landscape....

  4. Groundwater Waters

    Directory of Open Access Journals (Sweden)

    Ramón Llamas

    1999-10-01

    Full Text Available The groundwaters released through springs constituted a basic element for the survival and progressive development of human beings. Man came to learn how to take better advantage of these waters by digging wells, irrigation channels, and galleries. Nevertheless, these activities do not require cooperation nor the collective agreement of relatively large groups of people, as in the case of creating the necessary structures to take advantage of the resources of surfacewaters. The construction and operation of these structures was a powerful factor in the birth of an urban or civil society – the designated water civilizations. The difference between people taking advantage of groundwater, quasi-individually, and those of surface water, where people work in a group, has continued to the present day. Whereas earlier, this difference did not bring about any special problems, the technological advances of this century, especially theturbine pump, have led to a spectacular increase in the use of roundwater. This advance has significantly contributed to reducing hunger in the world and has provided potable water in developing countries. However, the almost generalized lack of planning and control in the exploitation of these groundwaters reflects that they are little or badly understood by the managers of water policy in almost every country. As such, problems have occurred which have often become exaggerated, giving rise to water-myths. These problems, though, should be addressed if the aim is the sustainable usage of surface water as well as groundwater. To counter any misconceptions and to seek solutions to the problems, distinct plans of action can be highlighted: educating the public; fomenting a system of participative management and decisive support for the communities of users of subterranean waters; integrating a sufficient number of experts in hydrology in the various water management organizations;and assuring transparency of the data on

  5. Hydration and Nanoconfined Water: Insights from Computer Simulations.

    Science.gov (United States)

    Alarcón, Laureano M; Rodríguez Fris, J A; Morini, Marcela A; Sierra, M Belén; Accordino, S A; Montes de Oca, J M; Pedroni, Viviana I; Appignanesi, Gustavo A

    2015-01-01

    The comprehension of the structure and behavior of water at interfaces and under nanoconfinement represents an issue of major concern in several central research areas like hydration, reaction dynamics and biology. From one side, water is known to play a dominant role in the structuring, the dynamics and the functionality of biological molecules, governing main processes like protein folding, protein binding and biological function. In turn, the same principles that rule biological organization at the molecular level are also operative for materials science processes that take place within a water environment, being responsible for the self-assembly of molecular structures to create synthetic supramolecular nanometrically-sized materials. Thus, the understanding of the principles of water hydration, including the development of a theory of hydrophobicity at the nanoscale, is imperative both from a fundamental and an applied standpoint. In this work we present some molecular dynamics studies of the structure and dynamics of water at different interfaces or confinement conditions, ranging from simple model hydrophobic interfaces with different geometrical constraints (in order to single out curvature effects), to self-assembled monolayers, proteins and phospholipid membranes. The tendency of the water molecules to sacrifice the lowest hydrogen bond (HB) coordination as possible at extended interfaces is revealed. This fact makes the first hydration layers to be highly oriented, in some situations even resembling the structure of hexagonal ice. A similar trend to maximize the number of HBs is shown to hold in cavity filling, with small subnanometric hydrophobic cavities remaining empty while larger cavities display an alternation of filled and dry states with a significant inner HB network. We also study interfaces with complex chemical and geometrical nature in order to determine how different conditions affect the local hydration properties. Thus, we show some

  6. Water Pressure. Water in Africa.

    Science.gov (United States)

    Garrett, Carly Sporer

    The Water in Africa Project was realized over a 2-year period by a team of Peace Corps volunteers. As part of an expanded, detailed design, resources were collected from over 90 volunteers serving in African countries, photos and stories were prepared, and standards-based learning units were created for K-12 students. This unit, "Water Pressure,"…

  7. Visualizing water

    Science.gov (United States)

    Baart, F.; van Gils, A.; Hagenaars, G.; Donchyts, G.; Eisemann, E.; van Velzen, J. W.

    2016-12-01

    A compelling visualization is captivating, beautiful and narrative. Here we show how melding the skills of computer graphics, art, statistics, and environmental modeling can be used to generate innovative, attractive and very informative visualizations. We focus on the topic of visualizing forecasts and measurements of water (water level, waves, currents, density, and salinity). For the field of computer graphics and arts, water is an important topic because it occurs in many natural scenes. For environmental modeling and statistics, water is an important topic because the water is essential for transport, a healthy environment, fruitful agriculture, and a safe environment.The different disciplines take different approaches to visualizing water. In computer graphics, one focusses on creating water as realistic looking as possible. The focus on realistic perception (versus the focus on the physical balance pursued by environmental scientists) resulted in fascinating renderings, as seen in recent games and movies. Visualization techniques for statistical results have benefited from the advancement in design and journalism, resulting in enthralling infographics. The field of environmental modeling has absorbed advances in contemporary cartography as seen in the latest interactive data-driven maps. We systematically review the design emerging types of water visualizations. The examples that we analyze range from dynamically animated forecasts, interactive paintings, infographics, modern cartography to web-based photorealistic rendering. By characterizing the intended audience, the design choices, the scales (e.g. time, space), and the explorability we provide a set of guidelines and genres. The unique contributions of the different fields show how the innovations in the current state of the art of water visualization have benefited from inter-disciplinary collaborations.

  8. Water Pots

    Institute of Scientific and Technical Information of China (English)

    蒋保平

    2005-01-01

    A water bearer in India had two large pots, each hung on each end of a pole which he carried across his neck. One of the pots had a crack in it, while the other pot was perfect and always delivered a full portion of water at the end of the long walk from the stream to the master's house, and the cracked pot was only half full when the water bearer arrived. For two years this went on daily. Of course, the perfect pot was proud of its perfection to which it was brought. But the poor cracked pot was ashamed of...

  9. Water Purification

    Science.gov (United States)

    1994-01-01

    The Vision Catalyst Purifier employs the basic technology developed by NASA to purify water aboard the Apollo spacecraft. However, it also uses an "erosion" technique. The purifier kills bacteria, viruses, and algae by "catalytic corrosion." A cartridge contains a silver-impregnated alumina bed with a large surface area. The catalyst bed converts oxygen in a pool of water to its most oxidative state, killing over 99 percent of the bacteria within five seconds. The cartridge also releases into the pool low levels of ionic silver and copper through a controlled process of erosion. Because the water becomes electrochemically active, no electricity is required.

  10. Probing carbonate in bone forming minerals on the nanometre scale.

    Science.gov (United States)

    Kłosowski, Michał M; Friederichs, Robert J; Nichol, Robert; Antolin, Nikolas; Carzaniga, Raffaella; Windl, Wolfgang; Best, Serena M; Shefelbine, Sandra J; McComb, David W; Porter, Alexandra E

    2015-07-01

    To devise new strategies to treat bone disease in an ageing society, a more detailed characterisation of the process by which bone mineralises is needed. In vitro studies have suggested that carbonated mineral might be a precursor for deposition of bone apatite. Increased carbonate content in bone may also have significant implications in altering the mechanical properties, for example in diseased bone. However, information about the chemistry and coordination environment of bone mineral, and their spatial distribution within healthy and diseased tissues, is lacking. Spatially resolved analytical transmission electron microscopy is the only method available to probe this information at the length scale of the collagen fibrils in bone. In this study, scanning transmission electron microscopy combined with electron energy-loss spectroscopy (STEM-EELS) was used to differentiate between calcium-containing biominerals (hydroxyapatite, carbonated hydroxyapatite, beta-tricalcium phosphate and calcite). A carbon K-edge peak at 290 eV is a direct marker of the presence of carbonate. We found that the oxygen K-edge structure changed most significantly between minerals allowing discrimination between calcium phosphates and calcium carbonates. The presence of carbonate in carbonated HA (CHA) was confirmed by the formation of peak at 533 eV in the oxygen K-edge. These observations were confirmed by simulations using density functional theory. Finally, we show that this method can be utilised to map carbonate from the crystallites in bone. We propose that our calibration library of EELS spectra could be extended to provide spatially resolved information about the coordination environment within bioceramic implants to stimulate the development of structural biomaterials. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  11. Thermal Conductivity of Suspension of Aggregating Nanometric Rods

    Directory of Open Access Journals (Sweden)

    Amine Ammar

    2016-12-01

    Full Text Available Enhancing thermal conductivity of simple fluids is of major interest in numerous applicative systems. One possibility of enhancing thermal properties consists of dispersing small conductive particles inside. However, in general, aggregation effects occur and then one must address systems composed of dispersed clusters composed of particles as well as the ones related to percolated networks. This papers analyzes the conductivity enhancement of different microstructures scaling from clusters dispersed into a simple matrix to the ones related to percolated networks exhibiting a fractal morphology.

  12. Evaluation of carboxymethyl moringa gum as nanometric carrier.

    Science.gov (United States)

    Rimpy; Abhishek; Ahuja, Munish

    2017-10-15

    In the present study, carboxymethylation of Moringa oleifera gum was carried out by reacting with monochloroacetic acid. Modified gum was characterised employing Fourier-transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, and Rheology study. The carboxymethyl modification of moringa gum was found to increase its degree of crystallinity, reduce viscosity and swelling, increase the surface roughness and render its more anionic. The interaction between carboxymethyl moringa gum and chitosan was optimised by 2-factor, 3-level central composite experimental design to prepare polyelectrolyte nanoparticle using ofloxacin, as a model drug. The optimal calculated parameters were found to be carboxymethyl moringa gum- 0.016% (w/v), chitosan- 0.012% (w/v) which provided polyelectrolyte nanoparticle of average particle size 231nm and zeta potential 28mV. Carboxymethyl moringa gum-chitosan polyelectrolyte nanoparticles show sustained in vitro release of ofloxacin upto 6h which followed first order kinetics with mechanism of release being erosion of polymer matrix. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. A new synthesis of ultrafine nanometre-sized bismuth particles

    Science.gov (United States)

    Balan, Lavinia; Schneider, Raphaël; Billaud, Denis; Fort, Yves; Ghanbaja, Jaafar

    2004-08-01

    A new synthesis of Bi(0) nanoparticles is reported. A low temperature solution phase reduction of BiCl3 with t-BuONa activated sodium hydride at 65 °C has been successfully used to prepare large quantities of colloidal Bi(0) nanoparticles with a diameter in the range 1.8-3.0 nm. The resulting Bi nanoparticles were characterized using transmission electron microscopy, XPS analysis and x-ray powder diffraction.

  14. On twin density and resistivity of nanometric Cu thin films

    Science.gov (United States)

    Barmak, Katayun; Liu, Xuan; Darbal, Amith; Nuhfer, N. Thomas; Choi, Dooho; Sun, Tik; Warren, Andrew P.; Coffey, Kevin R.; Toney, Michael F.

    2016-08-01

    Crystal orientation mapping in the transmission electron microscope was used to quantify the twin boundary length fraction per unit area for five Ta38Si14N48/SiO2 encapsulated Cu films with thicknesses in the range of 26-111 nm. The length fraction was found to be higher for a given twin-excluded grain size for these films compared with previously investigated SiO2 and Ta/SiO2 encapsulated films. The quantification of the twin length fraction per unit area allowed the contribution of the twin boundaries to the size effect resistivity to be assessed. It is shown that the increased resistivity of the Ta38Si14N48 encapsulated Cu films compared with the SiO2 and Ta/SiO2 encapsulated films is not a result of increased surface scattering, but it is a result of the increase in the density of twin boundaries. With twin boundaries included in the determination of grain size as a mean-intercept length, the resistivity data are well described by 2-parameter Matthiessen's rule summation of the Fuchs-Sondheimer and Mayadas Shatzkes models, with p and R parameters that are within experimental error equal to those in prior reports and are p = 0.48(+0.33/-0.31) and R = 0.27 ± 0.03.

  15. Nanometric mechanical cutting of metallic glass investigated using atomistic simulation

    Science.gov (United States)

    Wu, Cheng-Da; Fang, Te-Hua; Su, Jih-Kai

    2017-02-01

    The effects of cutting depth, tool nose radius, and temperature on the cutting mechanism and mechanics of amorphous NiAl workpieces are studied using molecular dynamics simulations based on the second-moment approximation of the many-body tight-binding potential. These effects are investigated in terms of atomic trajectories and flow field, shear strain, cutting force, resistance factor, cutting ratio, and pile-up characteristics. The simulation results show that a nanoscale chip with a shear plane of 135° is extruded by the tool from a workpiece surface during the cutting process. The workpiece atoms underneath the tool flow upward due to the adhesion force and elastic recovery. The required tangential force and normal force increase with increasing cutting depth and tool nose radius; both forces also increase with decreasing temperature. The resistance factor increases with increasing cutting depth and temperature, and decreases with increasing tool nose radius.

  16. Ultraporous poly(3,4-ethylenedioxythiophene) for nanometric electrochemical supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Aradilla, David [Departament d' Enginyeria Quimica, ETSEIB, Universitat Politecnica de Catalunya, Avda. Diagonal 647, Barcelona E-08028 (Spain); Center for Research in Nano-Engineering, Universitat Politecnica de Catalunya, Campus Sud, Edifici C' , C/Pasqual i Vila s/n, Barcelona E-08028 (Spain); Estrany, Francesc [Center for Research in Nano-Engineering, Universitat Politecnica de Catalunya, Campus Sud, Edifici C' , C/Pasqual i Vila s/n, Barcelona E-08028 (Spain); Departament d' Enginyeria Quimica, EUETIB, Universitat Politecnica de Catalunya, Comte d' Urgell 187, Barcelona E-08036 (Spain); Armelin, Elaine [Departament d' Enginyeria Quimica, ETSEIB, Universitat Politecnica de Catalunya, Avda. Diagonal 647, Barcelona E-08028 (Spain); Center for Research in Nano-Engineering, Universitat Politecnica de Catalunya, Campus Sud, Edifici C' , C/Pasqual i Vila s/n, Barcelona E-08028 (Spain); Aleman, Carlos, E-mail: carlos.aleman@upc.edu [Departament d' Enginyeria Quimica, ETSEIB, Universitat Politecnica de Catalunya, Avda. Diagonal 647, Barcelona E-08028 (Spain); Center for Research in Nano-Engineering, Universitat Politecnica de Catalunya, Campus Sud, Edifici C' , C/Pasqual i Vila s/n, Barcelona E-08028 (Spain)

    2012-04-30

    Ultrathin films of poly(3,4-ethylenedioxythiophene) (PEDOT) have been prepared by electropolymerization on steel and indium-tin oxide (ITO) substrates under identical experimental conditions. Scanning electron microscopy and atomic force microscopy indicate that the substrate affects dramatically both the morphology and topography of films when the polymerization times are very short. An ultraporous three-dimensional network involving ultrathin sticks with a fiber-like morphology was formed on ITO. Asymmetric and symmetric supercapacitors have been fabricated by assembling electrodes of PEDOT deposited on ITO and steel. The specific capacitance, electrochemical stability, supercapacitor behavior and Coulombic efficiency measured for devices with an ITO/steel configuration were similar to those reported for advanced PEDOT-inorganic hybrid composites. Furthermore, the performance of the ITO/steel assembly is higher than those determined for symmetric supercapacitors derived from two identical electrodes of PEDOT deposited on steel or on ITO. The unique properties of the asymmetric supercapacitors have been attributed to the ultraporous structure of the ultrathin films deposited on ITO, which is not significantly perturbed when the device is submitted to a very high number of consecutive oxidation-reduction processes, and the different electroactivities of the two electrodes. - Highlights: Black-Right-Pointing-Pointer Ultrathin poly(3,4-ethylenedioxythiophene) (PEDOT) films show fiber-like morphology. Black-Right-Pointing-Pointer The porosity of ultrathin PEDOT films induces a very high electrochemical stability. Black-Right-Pointing-Pointer Asymmetric supercapacitors made of ultrathin PEDOT behave like hybrid nanocomposites.

  17. Integrated Plasmon-Optic Circuits for Nanometric Sources and Sensors

    Science.gov (United States)

    2014-10-22

    Alivisatos, "Conjugation of DNA to silanized colloidal semiconductor nanocrystalline quantum dots," Chem. Mater. 14, 2113-2119 (2002).   14   21. S...absorption (peak at 460 nm and FWHM of 40 nm) and fluorescence (peak at ~ 496 nm and FWHM of 30 nm) spectra of 2 nm CdSe/ZnS USQDs. The absorbance

  18. Measuring and aligning accelerator components to the nanometre scale

    CERN Document Server

    Catalán Lasheras, N; Modena, M

    2014-01-01

    First tests have shown that the precision and accuracy required for linear colliders and other future accelerators of 10 micrometers is costly and lengthy with a process based on independent fiducializations of single components. Indeed, the systematic and random errors at each step add up during the process with the final accuracy of each component center well above the target. A new EC-funded training network named PACMAN (a study on Particle Accelerator Components Metrology and Alignment to the Nanometer scale) will propose and develop an alternative solution integrating all the alignment steps and a large number of technologies at the same time and location, in order to gain the required precision and accuracy. The network composed of seven industrial partners and nine universities and research centers will be based at CERN where ten doctoral students will explore the technology limitations of metrology. They will develop new techniques to measure magnetic and microwave fields, optical and non-contact sen...

  19. Water Pot

    Institute of Scientific and Technical Information of China (English)

    杨小平

    2003-01-01

    一只有裂缝的水罐为自己的缺陷而深感内疚,但它忽略了由它浇灌出的美丽花朵。人人都有属于自己的不足,只要正视它们,那么……A water bearer in India had two large pots, each hung on each end of a pole, which he carried across his neck. One of the pots had a crack(裂缝) in it, and while the other pot was perfect and always delivered a full portion of water at the end of the long walk from the stream to the master蒺s house, the cracked pot arrived only half full.For two years this went on daily, with the water bearer delivering one and one鄄half pots full of water to his master...

  20. Water Pollution

    Science.gov (United States)

    ... Home Page Brochures & Fact Sheets Environmental Health Topics Science Education Kids Environment | Kids Health Research Home Page At NIEHS ... Agents Water Pollution Environmental Science Basics Population Research Science Education Kids Environment | Kids Health Research Home Research At NIEHS ...

  1. Water Fibers

    CERN Document Server

    Douvidzon, Mark L; Martin, Leopoldo L; Carmon, Tal

    2016-01-01

    Fibers constitute the backbone of modern communication and are used in laser surgeries; fibers also genarate coherent X-ray, guided-sound and supercontinuum. In contrast, fibers for capillary oscillations, which are unique to liquids, were rarely considered in optofluidics. Here we fabricate fibers by water bridging an optical tapered-coupler to a microlensed coupler. Our water fibers are held in air and their length can be longer than a millimeter. These hybrid fibers co-confine two important oscillations in nature: capillary- and electromagnetic-. We optically record vibrations in the water fiber, including an audio-rate fundamental and its 3 overtones in a harmonic series, that one can hear in soundtracks attached. Transforming Micro-Electro-Mechanical-Systems [MEMS] to Micro-Electro-Capillary-Systems [MECS], boosts the device softness by a million to accordingly improve its response to minute forces. Furthermore, MECS are compatible with water, which is a most important liquid in our world.

  2. Water Safety

    Science.gov (United States)

    ... Looking for Health Lessons? Visit KidsHealth in the Classroom What Other Parents Are Reading Your Child's Development ( ... diaper. Wash hands after using the bathroom or changing diapers. Avoid swallowing or getting water in your ...

  3. Waterborne, all-polymeric, colloidal ‘raspberry’ particles with controllable hydrophobicity and water droplet adhesion properties

    Energy Technology Data Exchange (ETDEWEB)

    Telford, Andrew M. [School of Chemistry, The University of Sydney, NSW 2006 (Australia); Easton, Christopher D. [CSIRO Manufacturing Flagship, Clayton South, VIC 3169 (Australia); Hawkett, Brian S. [School of Chemistry, The University of Sydney, NSW 2006 (Australia); Neto, Chiara, E-mail: Chiara.neto@sydney.edu.au [School of Chemistry, The University of Sydney, NSW 2006 (Australia)

    2016-03-31

    We present a superhydrophobic coating made from waterborne, all-polymeric ‘raspberry’ particles, composed of a micrometric spherical core decorated with a corona of nanometric spherical particles. As-cast particles produced hydrophobic coatings that were highly adhesive to almost-spherical droplets of water, resembling the properties of some types of rose petals. The coatings could be made slippery to spherical water droplets, like the lotus leaf, by surface activation with air plasma followed by reaction with an alkyl-trichlorosilane. The silanisation of films of latex particles was investigated on two model surfaces (a flat polystyrene film and a monolayer of polystyrene waterborne microparticles) by X-ray photoelectron spectroscopy and water contact angle measurements, and applied to our recently-developed ‘raspberry’ particles to produce a superhydrophobic coating. - Highlights: • We have prepared superhydrophobic films using all-polymeric ‘raspberry’ particles. • We have prepared both ‘rose petal’ and ‘lotus leaf’ surfaces. • We have investigated the silanisation of complex latex particles.

  4. Direct observation of unstained biological specimens in water by the frequency transmission electric-field method using SEM.

    Directory of Open Access Journals (Sweden)

    Toshihiko Ogura

    Full Text Available Scanning electron microscopy (SEM is a powerful tool for the direct visualization of biological specimens at nanometre-scale resolution. However, images of unstained specimens in water using an atmospheric holder exhibit very poor contrast and heavy radiation damage. Here, we present a new form of microscopy, the frequency transmission electric-field (FTE method using SEM, that offers low radiation damage and high-contrast observation of unstained biological samples in water. The wet biological specimens are enclosed in two silicon nitride (SiN films. The metal-coated SiN film is irradiated using a focused modulation electron beam (EB at a low-accelerating voltage. A measurement terminal under the sample holder detects the electric-field frequency signal, which contains structural information relating to the biological specimens. Our results in very little radiation damage to the sample, and the observation image is similar to the transmission image, depending on the sample volume. Our developed method can easily be utilized for the observation of various biological specimens in water.

  5. Total Water Management - slides

    Science.gov (United States)

    Total Water Management (TWM) examines urban water systems in an interconnected manner. It encompasses reducing water demands, increasing water recycling and reuse, creating water supply assets from stormwater management, matching water quality to end-use needs, and achieving envi...

  6. Water availability, water quality water governance: the future ahead

    Science.gov (United States)

    Tundisi, J. G.; Matsumura-Tundisi, T.; Ciminelli, V. S.; Barbosa, F. A.

    2015-04-01

    The major challenge for achieving a sustainable future for water resources and water security is the integration of water availability, water quality and water governance. Water is unevenly distributed on Planet Earth and these disparities are cause of several economic, ecological and social differences in the societies of many countries and regions. As a consequence of human misuse, growth of urbanization and soil degradation, water quality is deteriorating continuously. Key components for the maintenance of water quantity and water quality are the vegetation cover of watersheds, reduction of the demand and new water governance that includes integrated management, predictive evaluation of impacts, and ecosystem services. Future research needs are discussed.

  7. Water Conservation and Water Storage

    Science.gov (United States)

    Narayanan, M.

    2014-12-01

    Water storage can be a viable part of the solution to water conservation. This means that we should include reservoirs. Regardless, one should evaluate all aspects of water conservation principles. Recent drought in California indicates that there is an urgent need to re-visit the techniques used to maintain the water supply-chain mechanism in the entire state. We all recognize the fact that fish and wildlife depend on the streams, rivers and wetlands for survival. It is a well-known fact that there is an immediate need to provide solid protection to all these resources. Laws and regulations should help meet the needs of natural systems. Farmers may be forced to drilling wells deeper than ever. But, they will be eventually depleting groundwater reserves. Needless to say that birds, fish and wildlife cannot access these groundwater table. California is talking a lot about conservation. Unfortunately, the conservation efforts have not established a strong visible hold. The Environmental Protection Agency has a plan called E2PLAN (Narayanan, 2012). It is EPA's plan for achieving energy and environmental performance, leadership, accountability, and carbon neutrality. In June 2011, the EPA published a comprehensive, multi-year planning document called Strategic Sustainability Performance Plan. The author has previously reported these in detail at the 2012 AGU fall meeting. References: Ziegler, Jay (15 JUNE 2014). The Conversation: Water conservation efforts aren't taking hold, but there are encouraging signs. THE SACRAMENTO BEE. California. Narayanan, Mysore. (2012). The Importance of Water Conservation in the 21st Century. 72nd AGU International Conference. Eos Transactions: American Geophysical Union, Vol. 92, No. 56, Fall Meeting Supplement, 2012. H31I - 1255.http://www.sacbee.com/2014/06/15/6479862/jay-ziegler-water-conservation.html#storylink=cpy

  8. Water Condensation

    DEFF Research Database (Denmark)

    Jensen, Kasper Risgaard; Fojan, Peter; Jensen, Rasmus Lund

    2014-01-01

    The condensation of water is a phenomenon occurring in multiple situations in everyday life, e.g., when fog is formed or when dew forms on the grass or on windows. This means that this phenomenon plays an important role within the different fields of science including meteorology, building physics......, and chemistry. In this review we address condensation models and simulations with the main focus on heterogeneous condensation of water. The condensation process is, at first, described from a thermodynamic viewpoint where the nucleation step is described by the classical nucleation theory. Further, we address...

  9. Water Spout

    Science.gov (United States)

    Greenslade, Thomas B., Jr.

    2013-01-01

    During the AAPT summer meeting at Creighton University in 2011, Vacek Miglus and I took pictures of early apparatus at the Creighton physics department. The apparatus in the left-hand picture, shown with the spigot closed, appeared to be a liquid-level device: the water level was the same in both the narrow tube and the flaring glass vase.…

  10. Water Spout

    Science.gov (United States)

    Greenslade, Thomas B., Jr.

    2013-01-01

    During the AAPT summer meeting at Creighton University in 2011, Vacek Miglus and I took pictures of early apparatus at the Creighton physics department. The apparatus in the left-hand picture, shown with the spigot closed, appeared to be a liquid-level device: the water level was the same in both the narrow tube and the flaring glass vase.…

  11. WATER USES

    Directory of Open Access Journals (Sweden)

    Adimasu Woldesenbet Worako

    2015-01-01

    Full Text Available Lake Hawassa is one of the Major Ethiopian Rift Valley Lakes which is situated in southernregional state, which has a closed basin system and receives water from only Tikurwuha Riverand runoff from the catchment. Quality of the lake water is vital for the surrounding communityfor proper and safe use of the lake. The present study was designed to examine thephysicochemical and biological water quality suitability for multiple purposes and to determinetrophic state index of the lake for a period of three months from December to February,2011/12. Water samples were collected from the lake on monthly basis and analyzed for allwater quality parameters by using standard methods. Data analysis was performed bydescriptive, multivariate analysis (MANOVA and Tukey-Kramer test. The overall waterquality parameters analytical results have been observed as pH (7.5, TDS (450.1, temp.(21.23°C, DO (17.85, turbidity (8.44 NTU, COD (48.73, BOD5 (117, Fˉ (12.8, NO3ˉ (5.27,PO43- (1.12, NO2ˉ (0.04, TN (5.42, TP (0.37, Clˉ (30.84, Mn (0.09, Zn(0.19, Na+(331,Chlorophyll-a(25.45μg/L, TC(11,883MPN/100ml and FC (99.67MPN/100ml and units forothers in mg/L. On the other hand, the value of indices for irrigation water quality was SAR(12.2-16, SSP (83.77-84.34%, MAR (93.83-95.37% and KR (5.71-7.18. The values of thewhole analyzed parameters have shown significant variation in site (P<0.05. As irrigation waterquality mainly focuses on the indices of SAR and EC/TDS, the lake water is in good conditionfor the purpose. The values of trace heavy metals were under permissible limits for multipleaspects. On average, the trophic state index of the Lake Hawassa was hypereutrophic(TSI = 72.6, as Carlson value category. In general, the lake water is not suitable for drinking,recreational and irrigation of some raw consuming crops but it is suitable for aquatic life.

  12. Estrutura e celularidade de meniscos frescos de coelhos (Oryctolagus cuniculus) preservados em glicerina Structure and cellularity of the fresh menisci (Oryctolagus cuniculus) of rabbits and the menisci preserved in glycerin

    OpenAIRE

    Vilela,Liana M.; Ricardo J. Del Carlo; João Carlos P. da Silva; Sérgio Luís P. Da Matta; Rodrigues,Mauricio Correia D.; Betânia S. Monteiro; Mastoby Miguel M. Martinez; Reis,Amanda Maria S.; Daniel P. Dias Machado; Liliane R. Lopes

    2010-01-01

    No presente estudo foi avaliada a arquitetura tecidual, a população celular, assim como a integridade e a distribuição dos tipos celulares em meniscos frescos de coelhos e preservados em glicerina 98%. Foram analisados meniscos mediais de coelhos recém abatidos, que foram distribuídos em três grupos: o grupo MF (n=7), composto por meniscos frescos, correspondeu ao grupo controle; o grupo MG (n=7), composto por meniscos preservados em glicerina 98%, por 30 dias, e o grupo MR (n=7), por menisco...

  13. Propriedades mecânicas de meniscos frescos de coelhos e preservados em glicerina 98% Mechanical properties of the fresh rabbit menisci and of the menisci preserved in glycerin 98%

    OpenAIRE

    Liana Mesquita Vilela; Ricardo Junqueira Del Carlo; Rubens Chaves de Oliveira; Mauricio Correia Daltro Rodrigues; Betânia Souza Monteiro; Amanda Maria Sena Reis; Daniel Portela Dias Machado

    2010-01-01

    O presente estudo avaliou a resistência à compressão de meniscos mediais de coelhos da raça Nova Zelândia, por meio de teste mecânico de compressão. Trinta meniscos foram distribuídos em três grupos: grupo MF, composto por dez meniscos frescos; grupo MG, dez meniscos preservados em glicerina 98%, por 30 dias, e grupo MR, dez meniscos preservados em glicerina 98%, por 30 dias e reidratados em NaCl 0,9%, por 12 horas. Os meniscos de cada grupo foram submetidos ao teste de compressão no sentido ...

  14. Specification of absorbed dose to water using model-based dose calculation algorithms for treatment planning in brachytherapy.

    Science.gov (United States)

    Tedgren, Åsa Carlsson; Carlsson, Gudrun Alm

    2013-04-21

    Model-based dose calculation algorithms (MBDCAs), recently introduced in treatment planning systems (TPS) for brachytherapy, calculate tissue absorbed doses. In the TPS framework, doses have hereto been reported as dose to water and water may still be preferred as a dose specification medium. Dose to tissue medium Dmed then needs to be converted into dose to water in tissue Dw,med. Methods to calculate absorbed dose to differently sized water compartments/cavities inside tissue, infinitesimal (used for definition of absorbed dose), small, large or intermediate, are reviewed. Burlin theory is applied to estimate photon energies at which cavity sizes in the range 1 nm-10 mm can be considered small or large. Photon and electron energy spectra are calculated at 1 cm distance from the central axis in cylindrical phantoms of bone, muscle and adipose tissue for 20, 50, 300 keV photons and photons from (125)I, (169)Yb and (192)Ir sources; ratios of mass-collision-stopping powers and mass energy absorption coefficients are calculated as applicable to convert Dmed into Dw,med for small and large cavities. Results show that 1-10 nm sized cavities are small at all investigated photon energies; 100 µm cavities are large only at photon energies <20 keV. A choice of an appropriate conversion coefficient Dw, med/Dmed is discussed in terms of the cavity size in relation to the size of important cellular targets. Free radicals from DNA bound water of nanometre dimensions contribute to DNA damage and cell killing and may be the most important water compartment in cells implying use of ratios of mass-collision-stopping powers for converting Dmed into Dw,med.

  15. Static and dynamic properties of curved vapour-liquid interfaces by massively parallel molecular dynamics simulation

    CERN Document Server

    Horsch, Martin T; Vrabec, Jadran; Glass, Colin W; Niethammer, Christoph; Bernreuther, Martin F; Müller, Erich A; Jackson, George

    2011-01-01

    Curved fluid interfaces are investigated on the nanometre length scale by molecular dynamics simulation. Thereby, droplets surrounded by a metastable vapour phase are stabilized in the canonical ensemble. Analogous simulations are conducted for cylindrical menisci separating vapour and liquid phases under confinement in planar nanopores. Regarding the emergence of nanodroplets during nucleation, a non-equilibrium phenomenon, both the non-steady dynamics of condensation processes and stationary quantities related to supersaturated vapours are considered. Results for the truncated and shifted Lennard-Jones fluid and for mixtures of quadrupolar fluids confirm the applicability of the capillarity approximation and the classical nucleation theory.

  16. Light & Water

    Directory of Open Access Journals (Sweden)

    Óscar Natividad Puig

    2013-06-01

    Full Text Available The proposal explores the Caos Theories, specifically, how applicable they are on local architectural interventions. It compiles a short study about possible variations of a same piece, in order to create difeerent ruled surfaces. Those pieces are distributed around a fractal attractor. The cores of these attractors are the ones responsible of collecting all the water flowing through the system. Once built, the project will enclose an open but covered space. Within this space, many different activities can be embraced, which allows its adaptability to each community where it?s placed. An open market will be the most common use though. It will allow selling agricultural products developed among the same community. Products irrigated with the extra water source collected by the cores of the fractal attractors.

  17. Troubled Waters

    Institute of Scientific and Technical Information of China (English)

    WANG CHONG

    2010-01-01

    @@ The diplomatic row between China and Japan over the latter's illegal detention of a Chinese fishing boat was initially resolved on September 24 when Japanese authorities released the boat's captain.But its repercussions have yet to be fully addressed. The Chinese Government and public protested strongly after Japanese coast guards captured the boat in waters off the Diaoyu Islands on September 7.Six days later,Japan freed all other crew members while keeping the captain in custody.

  18. [Material properties of meniscus tissue and the effect of the menisci on the compression behavior of the knee joint].

    Science.gov (United States)

    Kohn, D; Mussack, T; Plitz, W

    1993-01-01

    Specimens of meniscus tissue were taken from different locations of the medial and lateral meniscus. They were tested to failure in the tensometer and force elongation diagrams were recorded. 28 meniscus specimens (14 medial, 14 lateral) gained at autopsy were available for testing. The posterior third of the medial meniscus and the middle third of the lateral meniscus were the strongest and stiffest parts of the meniscus. Yet local differences within one meniscus were only subtle. One clinical significance of these data is, that for replacement of the medial and lateral meniscus the same homogeneous material can be employed. Six tests under compression were carried out using six knee specimens gained at autopsy. Knee compression tests yielded different results after radial cutting of the meniscus, whereas partial meniscectomy had no effect on deformation and hysteresis. These biomechanical results support the concept of partial meniscectomy and preservation of the meniscal periphery. But they cannot be related to the problem of possible degenerative arthritis after partial meniscectomy.

  19. Unicompartmental knee prostheses: in vitro wear assessment of the menisci tibial insert after two different fixation methods

    Energy Technology Data Exchange (ETDEWEB)

    Affatato, S; Spinelli, M; Zavalloni, M; Viceconti, M [Laboratorio di Tecnologia Medica, Istituti Ortopedici Rizzoli, Via di Barbiano, 1/10, 40136 Bologna (Italy); Carmignato, S [Laboratorio di Metrologia Geometrica e Industriale, Universita degli Studi di Padova, Padova (Italy); Lopomo, N; Marcacci, M [Laboratorio di Biomeccanica, Istituti Ortopedici Rizzoli, Bologna (Italy)], E-mail: affatato@tecno.ior.it

    2008-10-07

    Knee osteoarthritis is a complex clinical scenario where many biological and mechanical factors influence the severity of articular degenerative changes. Minimally invasive knee prosthetic surgery, with only a compartment replacement (unicompartmental knee replacement), might be a good compromise between osteotomy and total knee prosthesis. The focus of this study was to develop and validate a protocol to assess the fixation method of the femoral components in mechanical simulation, for pre-clinical validation; the wear behaviour of two different fixation frames was quantified and compared. In particular, two different wear tests were conducted using the same knee simulator, the same load profiles and the same kinematics; two different fixation methods were applied to the femoral sleds (synthetic femur and metal block). Surface characterization on both articulating bearings was performed by a roughness measuring machine and coordinate measuring machine. The wear produced by the tibial inserts using the synthetic femur was considerably higher than the wear registered by the metal-block holder. Roughness measurements on femoral sleds showed a limited number of scratches with high R{sub t} values for the metal-block set-up; the damaged surface broadened in the case of femoral condyles and tibial inserts mounted on composite bone, but lower R{sub t} and linear penetration values were measured. The two holding frames showed different wear activities as a consequence of dissimilar dynamic performance. Further observations should be made in vivo to prove the actual importance of synthetic bone simulations and specific material behaviour.

  20. USE OF POROUS BIODEGRADABLE POLYMER IMPLANTS IN MENISCUS RECONSTRUCTION .2. BIOLOGICAL EVALUATION OF POROUS BIODEGRADABLE POLYMER IMPLANTS IN MENISCI

    NARCIS (Netherlands)

    ELEMA, H; DEGROOT, JH; NIJENHUIS, AJ; PENNINGS, AJ; VETH, RPH; JANSEN, HWB

    1990-01-01

    Several series of porous, biodegradable PU/PLLA foams were used for meniscus reconstruction in dogs. PLLA-fiber reinforced PU/PLLA composites, PU/PLLA, and PU foams were implanted in severe meniscus lesions. The healing process was initiated as a result of blood vessels' and other cells' ingrowth in

  1. Enhanced boundary lubrication properties of engineered menisci by lubricin localization with insulin-like growth factor I treatment.

    Science.gov (United States)

    Bonnevie, Edward D; Puetzer, Jennifer L; Bonassar, Lawrence J

    2014-06-27

    In this study we analyzed the effects of IGF-I on the boundary lubricating ability of engineered meniscal tissue using a high density collagen gel seeded with meniscal fibrochondrocytes. Biochemical, histological, immunohistochemical, and tribological analyses were carried out to determine a construct's ability to functionally localize lubricin. Our study revealed that supplementation with IGF-I enhanced both the proliferation of cells within the construct as well as enhanced the anabolic activity of the seeded cells. Growth factor supplementation also facilitated the localization of ECM constituents (i.e. fibronectin and type II collagen) near the tissue surface that are important for the localization of lubricin, a boundary lubricant. Consequently, we found localized lubricin in the constructs supplemented with IGF-I. Tribologically, we demonstrated that lubricin serves as a boundary lubricant adsorbed to native meniscal surfaces. Lubricin removal from the native meniscus surface increased boundary friction coefficient by 40%. For the engineered constructs, the lubricin localization facilitated by growth factor supplementation also reduced friction coefficient by a similar margin, but similar results were not evident in control constructs. This study demonstrates that the use of growth factors in meniscal tissue engineering can enhance tribological properties by facilitating the localization of boundary lubricants at the surface of engineered tissue.

  2. Water markets between Mexican water user associations

    NARCIS (Netherlands)

    Kloezen, W.H.

    1998-01-01

    Internationally, introducing water markets is regarded as a strong alternative institutional arrangement for managing irrigation water more effectively. Also in Mexico, the National Water Law of 1992 allows individual farmers as well as water user associations (WUA) to trade water. Although farmer

  3. Water markets between Mexican water user associations

    NARCIS (Netherlands)

    Kloezen, W.H.

    1998-01-01

    Internationally, introducing water markets is regarded as a strong alternative institutional arrangement for managing irrigation water more effectively. Also in Mexico, the National Water Law of 1992 allows individual farmers as well as water user associations (WUA) to trade water. Although farmer t

  4. Reuse & Recirculation of Filter Backwash Water of Water Treatment Water

    Directory of Open Access Journals (Sweden)

    Mangesh L. Jibhakate

    2017-04-01

    Full Text Available Most of the water treatment plant, filtration is done by means of sand filtration process. Due to continuous filtration process, sand pores get clogged and decreases the efficiency. For mitigating such problem, reverse flow of water & air i.e. backwashing process is carried out. To carry out backwashing operation, 4% of treated water has been utilized and will result in muddy water known as backwash water. This backwash water is then discharged into a natural stream or storage tank near the plant for recirculation. The present study includes a trial for the reuse & recirculation of backwash water.

  5. Improved water does not mean safe water

    Science.gov (United States)

    MacDonald, L. H.; Guo, Y.; Schwab, K. J.

    2012-12-01

    This work presents a model for estimating global access to drinking water that meets World Health Organization (WHO) water quality guidelines. The currently accepted international estimate of global access to safe water, the WHO and United Nations Children's Fund's (UNICEF) Joint Monitoring Program (JMP) report, estimates the population with access to water service infrastructure that is classified as improved and unimproved. The JMP report uses access to improved water sources as a proxy for access to safe water, but improved water sources do not always meet drinking water quality guidelines. Therefore, this report likely overestimates the number of people with access to safe water. Based on the JMP estimate, the United Nations has recently announced that the world has reached the Millennium Development Goal (MDG) target for access to safe water. Our new framework employs a statistical model that incorporates source water quality, water supply interruptions, water storage practices, and point of use water treatment to estimate access to safe water, resulting in a figure that is lower than the JMP estimate of global access to safe water. We estimate that at least 28% of the world does not have access to safe water today, as compared to the JMP estimate of 12%. These findings indicate that much more work is needed on the international scale to meet the MDG target for access to safe water.

  6. Healing Waters

    Directory of Open Access Journals (Sweden)

    Cátedra Tomás, María

    2009-06-01

    Full Text Available Based on fieldwork in four different spas —two in Spain and two in Portugal— this paper shows the mutiple social mediations operating in water therapies in different contexts: from the local use inscribed in popular knowledge, including playful elements inserted in therapeutic practices under the illusion of a return to nature when nature itself has stopped being «natural», to others in which leisure time is an expression of an exclusive life style including a reevaluation of landscape as part of a time-bound aesthetics and as a refuge from urban stress. These different uses of water allow us to understand spas both as nature sanatoriums as well as a form of business where medical power bends to the interests of turistic enterpreneurs transformed into health advisors, linked to different conceptions not only of water but also of society itself.

    Focalizando la reflexión en cuatro balnearios diferentes —dos en España y dos en Portugal—, el artículo muestra las múltiples mediaciones sociales que operan en la terapéutica del agua en diferentes contextos: desde el uso local inserto en saberes populares, incluyendo lo lúdico en lo terapéutico que puede conectarse con la ilusión de un regreso a la naturaleza cuando ésta ya ha dejado de ser “natural”, a otros en los que el ocio es expresión de un estilo de vida exclusivo que incluye un acercamiento al paisaje como parte de la estética de una época y como refugio ante el stress urbano. Se observa así cómo estos usos del agua, que permiten concebir los balnearios bien como sanatorios de la naturaleza bien como negocios en los que el poder médico se pliega al de promotores turísticos convertidos en asesores de salud, se vinculan a concepciones diferentes no sólo del agua, sino de la sociedad misma y sus diferentes grupos.

  7. Bottled Water and Fluoride

    Science.gov (United States)

    ... bottled water and fluoride. Does bottled water contain fluoride? Bottled water products may contain fluoride, depending on ... How can I find out the level of fluoride in bottled water? The FDA does not require ...

  8. Why Do Eyes Water?

    Science.gov (United States)

    ... Lifesaver Kids Talk About: Coaches Why Do Eyes Water? KidsHealth > For Kids > Why Do Eyes Water? Print ... out of your nose. continue Why Do Eyes Water? Eyes water for lots of different reasons besides ...

  9. Lead and tap water

    Science.gov (United States)

    Water contaminated with lead ... The Environmental Protection Agency (EPA) monitors drinking water in the United States. It requires water suppliers to produce annual water quality reports. These reports include information about lead amounts, and they ...

  10. Why Do Eyes Water?

    Science.gov (United States)

    ... Happens in the Operating Room? Why Do Eyes Water? KidsHealth > For Kids > Why Do Eyes Water? A ... out of your nose. continue Why Do Eyes Water? Eyes water for lots of different reasons besides ...

  11. Water chemistry and poultry processing water quality

    Science.gov (United States)

    This study examined the influences of water chemistry on the quality of process water used in immersion chillers. During commercial poultry processing the bird carcasses come in direct contact with process water during washing and chilling operations. Contamination of the process water with bacteria...

  12. Virtual water trade and world water resources.

    Science.gov (United States)

    Oki, T; Kanae, S

    2004-01-01

    Global virtual water trade was quantitatively estimated and evaluated. The basic idea of how to estimate unit requirement of water resources to produce each commodity is introduced and values for major agricultural and stock products are presented. The concept of virtual water and the quantitative estimates can help in assessing a more realistic water scarcity index in each country, projecting future water demand for food supply, increasing public awareness on water, and identifying the processes wasting water in the production. Really required water in exporting countries is generally smaller than virtually required water in importing countries, reflecting the comparative advantage of water use efficiency, and it is estimated to be 680 km3/y for 2000. On the contrary the virtually required water for the same year is estimated to be 1,130 km3/y, and the difference of 450 km3/y is virtually saved by global trade. However, solely virtual water should not be used for any decision making since the idea of virtual water implies only the usage and influence of water and no concerns on social, cultural, and environmental implications. Virtual water trade also does not consider other limiting factors than water.

  13. Everyone into the Water!

    Science.gov (United States)

    Hennessey, Christina L.

    2007-01-01

    As the days grow longer and warmer with the approach of summer, everyone's thoughts turn to the outdoors and the clear blue of water sports. While recreational choices range from in-the-water activities like water polo to under-the-water sports like free diving, and on-the-water diversions like water skiing, this article focuses on print, video,…

  14. Testing the Waters.

    Science.gov (United States)

    Finks, Mason

    1993-01-01

    Provides information about home drinking water treatment systems to address concerns about the safety and quality of drinking water. Discusses water testing, filtration, product options and selection, water testing resources, water treatment device guidelines, water analysis terminology, and laboratory selection. (MCO)

  15. Water resources data, Indiana, water year 1993

    Science.gov (United States)

    Stewart, James A.; Keeton, Charles R.; Benedict, Brian L.; Hammil, Lowell E.

    1994-01-01

    Water resources data for the 1993 water year for Indiana consist of records of discharge, stage, and water quality of streams and wells; reservoir stage and contents; and water levels in lakes and wells. This report contains records of discharge for 175 stream-gaging station, stage for 5 stream station, 1 sediment station, stage and contents for 1 reservoir, water quality for 3 streams, and water levels for 80 lakes and 94 observation wells. These data represent that part of the National Water Data System operated by the U.S. Geological Survey in Indiana in cooperation with State and Federal agencies.

  16. Water resources data, Indiana, water year 1992

    Science.gov (United States)

    Stewart, James A.; Keeton, Charles R.; Benedict, Brian L.; Hammil, Lowell E.

    1993-01-01

    Water resources data for the 1992 water year for Indiana consist of records of discharge, stage, and water quality of streams and wells; reservoir stage and contents; and water levels in lakes and wells. This report contains records of discharge for 175 stream-gaging stations, stage for 7 stream stations, 1 sediment station, stage and contents for 1 reservoir, water quality for 3 streams, and water levels for 80 lakes and 94 observation wells. These data represent that part of the National Water Data System operated by the U.S. Geological Survey in Indiana in cooperation with State and Federal agencies.

  17. Water resources data, Indiana, water year 1991

    Science.gov (United States)

    Stewart, James A.; Deiwert, Clyde E.

    1992-01-01

    Water resources data for the 1991 water year for Indiana consist of records of discharge, stage, and water quality of streams and wells; reservoir stage and contents; and water levels in lakes and wells. This report contains records of discharge for 183 stream-gaging stations, stage for 7 stream stations, stage and contents for 1 reservoir, water quality for 3 streams, and water levels for 80 lakes and 95 observation wells. These data represent that part of the National Water Data System operated by the U.S. Geological Survey in Indiana in cooperation with State and Federal Agencies.

  18. Artificial Ground Water Recharge with Surface Water

    Science.gov (United States)

    Heviánková, Silvie; Marschalko, Marian; Chromíková, Jitka; Kyncl, Miroslav; Korabík, Michal

    2016-10-01

    With regard to the adverse manifestations of the recent climatic conditions, Europe as well as the world have been facing the problem of dry periods that reduce the possibility of drawing drinking water from the underground sources. The paper aims to describe artificial ground water recharge (infiltration) that may be used to restock underground sources with surface water from natural streams. Among many conditions, it aims to specify the boundary and operational conditions of the individual aspects of the artificial ground water recharge technology. The principle of artificial infiltration lies in the design of a technical system, by means of which it is possible to conduct surplus water from one place (in this case a natural stream) into another place (an infiltration basin in this case). This way, the water begins to infiltrate into the underground resources of drinking water, while the mixed water composition corresponds to the water parameters required for drinking water.

  19. Capillary self-assembly of floating bodies

    Science.gov (United States)

    Jung, Sunghwan; Thompson, Paul; Bush, John

    2007-11-01

    We study the self-assembly of bodies supported on the water surface by surface tension. Attractive and repulsive capillary forces exist between menisci of, respectively, the same and opposite signs. In nature, floating objects (e.g. mosquito larvae) thus interact through capillary forces to form coherent packings on the water surface. We here present the results of an experimental investigation of such capillary pattern formation. Thin elliptical metal sheets were designed to have variable shape, flexibility and mass distribution. On the water surface, mono-, bi-, or tri-polar menisci could thus be achieved. The influence of the form of the menisci on the packings arising from the interaction of multiple floaters is explored. Biological applications are discussed.

  20. Smart Water: Energy-Water Optimization in Drinking Water Systems

    Science.gov (United States)

    This project aims to develop and commercialize a Smart Water Platform – Sensor-based Data-driven Energy-Water Optimization technology in drinking water systems. The key technological advances rely on cross-platform data acquisition and management system, model-based real-time sys...

  1. Water, Water Everywhere: Phase Diagrams of Ordinary Water Substance

    Science.gov (United States)

    Glasser, L.

    2004-01-01

    The full phase diagram of water in the form of a graphical representation of the three-dimensional (3D) PVT diagram using authentic data is presented. An interesting controversy regarding the phase behavior of water was the much-touted proposal of a solid phase of water, polywater, supposedly stable under atmospheric conditions.

  2. Water resources data, Indiana, water year 2001

    Science.gov (United States)

    Stewart, James A.; Keeton, Charles R.; Hammil, Lowell E.; Nguyen, Hieu T.; Majors, Deborah K.

    2002-01-01

    Water resources data for the 2001 water year for Indiana consists of records of discharge, stage, and water quality of streams and wells; reservoir stage and contents; and water levels in lakes and wells. This report contains records of discharge for 163 stream-gaging stations, stage for 8 stream stations, stage and contents for 1 reservoir, water quality for 1 stream, water temperature at 11 sites, sediment analysis for 1 stream, water levels for 78 lakes and 88 observation wells. Also included are records of miscellaneous discharge measurements, miscellaneous levels and miscellaneous water-quality, not part of the systematic data-collection program. Data contained in this report represent that part of the National Water Data System operated by the U.S. Geological Survey in Indiana in cooperation with State and Federal agencies.

  3. Urban water recycling.

    Science.gov (United States)

    Asano, T

    2005-01-01

    Increasing urbanization has resulted in an uneven distribution of population, industries, and water in urban areas; thus, imposing unprecedented pressures on water supplies and water pollution control. These pressures are exacerbated during the periods of drought and climatic uncertainties. The purpose of this paper is to summarize emergence of water reclamation, recycling and reuse as a vital component of sustainable water resources in the context of integrated water resources management in urban and rural areas. Water quality requirements and health and public acceptance issues related to water reuse are also discussed. Reclaimed water is a locally controllable water resource that exists right at the doorstep of the urban environment, where water is needed the most and priced the highest. Closing the water cycle loop not only is technically feasible in agriculture, industries, and municipalities but also makes economic sense. Society no longer has the luxury of using water only once.

  4. Water Pollution. Project COMPSEP.

    Science.gov (United States)

    Lantz, H. B., Jr.

    This is an introductory program on water pollution. Examined are the cause and effect relationships of water pollution, sources of water pollution, and possible alternatives to effect solutions from our water pollution problems. Included is background information on water pollution, a glossary of pollution terminology, a script for a slide script…

  5. Crowdsourcing Water Quality Data

    OpenAIRE

    World Bank

    2016-01-01

    Using mobile phone technologies coupled with water quality testing, there is great opportunity to increase the awareness of water quality throughout rural and urban communities in developing countries. Whether the focus is on empowering citizens with information about the quality of water they use in daily life or providing scientific data to water managers to help them deliver safe water to the ...

  6. Global water governance

    NARCIS (Netherlands)

    Gupta, J.; Falkner, R.

    2013-01-01

    Although (fresh) water challenges are primarily local in nature, globalization has led to feedback effects that make many water challenges global in nature. This chapter examines global water governance. It discusses four phases of water governance, argues that water governance is dispersed and

  7. Global water governance

    NARCIS (Netherlands)

    Gupta, J.; Falkner, R.

    2013-01-01

    Although (fresh) water challenges are primarily local in nature, globalization has led to feedback effects that make many water challenges global in nature. This chapter examines global water governance. It discusses four phases of water governance, argues that water governance is dispersed and inco

  8. Water resources data, Indiana, water year 2000

    Science.gov (United States)

    Stewart, James A.; Keeton, Charles R.; Hammil, Lowell E.; Nguyen, Hieu T.; Majors, Deborah K.

    2001-01-01

    Water resource data for the 2000 water year for Indiana consists of records of discharge, stage, and water quality of streams and wells; reservoir stage and contents; and water levels in lakes and wells. This report contains records of discharge for 166 stream-gaging stations, stage for 7 stream stations, stage and contents for 1 reservoir, water quality for 2 streams, sediment analysis for 1 stream, water levels for 79 lakes and 89 observation wells. Also included are records of miscellaneous discharge measurements, miscellaneous levels and miscellaneous water-quality, not part of the systematic data-collection program. Data contained in this report represent that part of the the National Water Data System operated by the U.S. Geological Survey in Indiana in cooperation with State and Federal agencies.

  9. Oxidation behavior of ferritic-martensitic and ODS steels in supercritical water

    Science.gov (United States)

    Bischoff, Jeremy

    water corroded much faster than those in steam (1.5 to 2 times faster). Additionally, during these corrosion tests a marker experiment was performed with the deposition of micrometric palladium markers on the surface of some samples prior to oxidation. The markers were found at the outer-inner layer interface, consistent with a corrosion mechanism of outward migration of iron to form the outer layer and inward migration of oxygen to form the inner layer. The discrepancy between the SCW and steam environments suggests that the outward migration of iron may be the rate-limiting step. A detailed study of the oxide advancement was performed using the TEM by analyzing the inner and diffusion layer structure. Energy-filtered TEM images were acquired to analyze the micrometric and nanometric distribution of elements in these layers. Such images from the inner layer revealed the presence of localized chromium enrichment regions associated with the presence of pores. Additionally, an iron-chromium nanometric segregation was observed and may be associated with the mixture of Fe3O4 and FeCr2O4. In the diffusion layer, small nanometric chromium-rich oxide particles were seen within metal grains. The (Fe,Cr)3O4 spinel oxide has an inverse spinel structure as Fe3O4 but becomes normal spinel as FeCr 2O4, thus the structure changes depending on the chromium content. Additionally, the spinel structure was analyzed using the ligand theory and showed that chromium does not migrate and that the main diffusing species is the Fe2+ ion. Calculations of the amount of iron leaving the inner layer showed that this amount accounted for the amount of iron necessary to form the outer layer, thus no dissolution of oxide in SCW is observed. Additionally, the differences in oxidation behavior in steam and SCW suggest that the rate-limiting step for the corrosion of ferritic-martensitic steels is the iron outward migration. The iron migration is driven by the gradient in the Fe2+/Fe 3+ ratio and is

  10. Water neutral: reducing and ofsetting water footprints

    NARCIS (Netherlands)

    Hoekstra, Arjen Ysbert

    2008-01-01

    During the past few years the concept of the ‘water footprint’ has started to receive recognition within governments, non-governmental organizations, businesses and media as a useful indicator of water use. The increased interest in the water-footprint concept has prompted the question about what

  11. Water safety and drowning

    Science.gov (United States)

    ... among people of all ages. Learning and practicing water safety is important to prevent drowning accidents. ... Water safety tips for all ages include: Learn CPR Never swim alone Never dive into water unless ...

  12. Water Policies of Turkey

    Directory of Open Access Journals (Sweden)

    Hakan Istanbulluoglu

    2011-06-01

    Full Text Available Water is one of our most critical resources. Civilization has historically flourished around major waterways. The most important uses of water are; agricultural, industrial and domestic use. This critical resource is under threat around the world. In the next 20 years, the quantity of water available to everyone is predicted to decrease by 30%. 40% of the world\\\\\\\\\\\\\\'s inhabitants currently have insufficient fresh water for minimal hygiene. In 2000 more than 2.2 million people died from waterborne diseases. Water politics is politics affected by water and water resources. There are connections between water resources, water systems, and international security and conflict. Today, water is a strategic resource in the globe and an important element in many political conflicts. Turkey can be faced severe water-stress in the near future. Therefore Turkey has to develop realistic and feasible water policy for future generations. [TAF Prev Med Bull 2011; 10(3.000: 327-338

  13. Tsunamis: Water Quality

    Science.gov (United States)

    ... Landslides Tornadoes Tsunamis Volcanoes Wildfires Winter Weather Tsunamis: Water Quality Language: English Español (Spanish) Recommend on Facebook ... about testing should be directed to local authorities. Water for Drinking, Cooking, and Personal Hygiene Safe water ...

  14. Public Waters Inventory Maps

    Data.gov (United States)

    Minnesota Department of Natural Resources — This theme is a scanned and rectified version of the Minnesota DNR - Division of Waters "Public Waters Inventory" (PWI) maps. DNR Waters utilizes a small scale...

  15. Alles is water

    NARCIS (Netherlands)

    Wal, van der A.

    2013-01-01

    Inaugurele rede bij de aanvaarding van buitengewoon hoogleraarschap in Electrochemical Water Treatment. De aandachtsgebieden in zijn professoraat richten zich achtereenvolgens op: a) energiezuinige ontzouting van water, b) selectieve verwijdering van ionen uit water, c) terugwinning van waardevolle

  16. Water in diet

    Science.gov (United States)

    ... of the weight of the human body. Without water, humans would die in a few days. All the ... the water is made during the process of metabolism . You also get water through liquid foods and beverages, such as soup, ...

  17. Hydrography - Water Resources

    Data.gov (United States)

    NSGIC Education | GIS Inventory — A Water Resource is a DEP primary facility type related to the Water Use Planning Program. The sub-facility types related to Water Resources that are included are:...

  18. Water Safety Quiz

    Science.gov (United States)

    ... Prepare for Emergencies Types of Emergencies Take the Water Safety Quiz Trivia quiz loading... Please enable javascript. Stay Safe Around Water Download water safety tips in English or Spanish ...

  19. Water Quality Monitoring

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Our water quality sampling program is to determine the quality of Moosehorn's lakes and a limited number of streams. Water quality is a measure of the body of water,...

  20. The Water Diversion Project

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    One of the basic characteristics of water distribution in China is that there is a deluge of water in the south and a deficiency in the north. To ease the water shortage in the north, the Chinese Government

  1. Alles is water

    NARCIS (Netherlands)

    Wal, van der A.

    2013-01-01

    Inaugurele rede bij de aanvaarding van buitengewoon hoogleraarschap in Electrochemical Water Treatment. De aandachtsgebieden in zijn professoraat richten zich achtereenvolgens op: a) energiezuinige ontzouting van water, b) selectieve verwijdering van ionen uit water, c) terugwinning van waardevolle

  2. Hydrography - Water Resources

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — A Water Resource is a DEP primary facility type related to the Water Use Planning Program. The sub-facility types related to Water Resources that are included are:...

  3. Water Innovation and Technology

    Science.gov (United States)

    Water technologies are a specific sector that EPA works to address through the water technology cluster, aging infrastructure research, green infrastructure, and major industry meetings such as WEFTEC.

  4. Water Quality of Hills Water, Supply Water and RO Water Machine at Ulu Yam Selangor

    Science.gov (United States)

    Ngadiman, N.; ‘I Bahari, N.; Kaamin, M.; Hamid, N. B.; Mokhtar, M.; Sahat, S.

    2016-07-01

    The rapid development resulted in the deterioration of the quality of drinking water in Malaysia. Recognizing the importance of water quality, new alternatives for drinking water such as mineral water processing from reverse osmosis (RO) machine become more popular. Hence, the demand for mineral water, natural spring water or water from the hills or mountains rose lately. More consumers believed the quality of these spring water better than other source of drinking water. However, the quality of all the drinking water sources is to meet the required quality standard. Therefore, this paper aims to measure the quality of the waters from hills, from RO machine and the water supply in Ulu Yam, Selangor Batang Kali, Malaysia. The water quality was determined based on following parameters: ammoniacal nitrogen (NH3), iron (Fe), turbidity (NTU) and pH. The results show that the water from hills has better quality compared to water supply and water from RO machine. The value of NH3 ranged from 0.03 mg/L- 0.67 mg/L; Fe was from 0.03mg/L - 0.12 mg/L, turbidity at 0.42 NTU - 0.88 NTU and pH is at 6.60 - 0.71. Based on the studied parameters, all three types of water are fit for drinking and have met the required national drinking water quality standard.

  5. Water Treatment Group

    Data.gov (United States)

    Federal Laboratory Consortium — This team researches and designs desalination, water treatment, and wastewater treatment systems. These systems remediate water containing hazardous c hemicals and...

  6. 2010 Water & Aqueous Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Dor Ben-Amotz

    2010-08-13

    Water covers more than two thirds of the surface of the Earth and about the same fraction of water forms the total mass of a human body. Since the early days of our civilization water has also been in the focus of technological developments, starting from converting it to wine to more modern achievements. The meeting will focus on recent advances in experimental, theoretical, and computational understanding of the behavior of the most important and fascinating liquid in a variety of situations and applications. The emphasis will be less on water properties per se than on water as a medium in which fundamental dynamic and reactive processes take place. In the following sessions, speakers will discuss the latest breakthroughs in unraveling these processes at the molecular level: Water in Solutions; Water in Motion I and II; Water in Biology I and II; Water in the Environment I and II; Water in Confined Geometries and Water in Discussion (keynote lecture and poster winners presentations).

  7. Water management strategy overview

    Energy Technology Data Exchange (ETDEWEB)

    Ducette, B. [Suncor Energy Inc. Oil Sands, Fort McMurray, AB (Canada)

    2003-07-01

    Suncor's oil sands operations produce 225,000 bbl/day of crude oil products from Alberta's Fort McMurray area. Water is a key resource used for enhanced recovery methods to produce crude oil products from oil sands. A water management strategy is required to monitor and control the amount of water used in the bitumen liberation process, cooling, the steam assisted gravity drainage process, steam for cogeneration, an energy transfer medium, a transportation medium, feedstock, and potable water. The water management strategy is designed to manage both short and long term water issues and develop sustainable water management strategies in an integrated manner. The strategy also encourages open communication on water to optimize synergy between operators, energy producers, and governments. The opportunities and challenges of a water management strategy were outlined with reference to recycling opportunities, managing water chemistry, and improving the ability to measure water use.

  8. Sustainability and Water

    Science.gov (United States)

    Sharma, Virender A.

    2009-07-01

    World's population numbered 6.1 billion in 2000 and is currently increasing at a rate of about 77 million per year. By 2025, the estimated total world population will be of the order of 7.9 billion. Water plays a central role in any systematic appraisal of life sustaining requirements. Water also strongly influences economic activity (both production and consumption) and social roles. Fresh water is distributed unevenly, with nearly 500 million people suffering water stress or serious water scarcity. Two-thirds of the world's population may be subjected to moderate to high water stress in 2025. It is estimated that by 2025, the total water use will increase by to 40%. The resources of water supply and recreation may also come under stress due to changes in climate such as water balance for Lake Balaton (Hungary). Conventional urban water systems such as water supply, wastewater, and storm water management are also currently going through stress and require major rethinking. To maintain urban water systems efficiently in the future, a flexibility approach will allow incorporation of new technologies and adaptation to external changes (for example society or climate change). Because water is an essential resource for sustaining health, both the quantity and quality of available water supplies must be improved. The impact of water quality on human health is severe, with millions of deaths each year from water-borne diseases, while water pollution and aquatic ecosystem destruction continue to rise. Additionally, emerging contaminants such as endocrine disruptor chemicals (EDCs), pharmaceuticals, and toxins in the water body are also of a great concern. An innovative ferrate(VI) technology is highly effective in removing these contaminants in water. This technology is green, which addresses problems associated with chlorination and ozonation for treating pollutants present in water and wastewater. Examples are presented to demonstrate the applications of ferrate

  9. Water Footprints and Sustainable Water Allocation

    Directory of Open Access Journals (Sweden)

    Arjen Y. Hoekstra

    2015-12-01

    Full Text Available Water Footprint Assessment (WFA is a quickly growing research field. This Special Issue contains a selection of papers advancing the field or showing innovative applications. The first seven papers are geographic WFA studies, from an urban to a continental scale; the next five papers have a global scope; the final five papers focus on water sustainability from the business point of view. The collection of papers shows that the historical picture of a town relying on its hinterland for its supply of water and food is no longer true: the water footprint of urban consumers is global. It has become clear that wise water governance is no longer the exclusive domain of government, even though water is and will remain a public resource with government in a primary role. With most water being used for producing our food and other consumer goods, and with product supply chains becoming increasingly complex and global, there is a growing awareness that consumers, companies and investors also have a key role. The interest in sustainable water use grows quickly, in both civil society and business communities, but the poor state of transparency of companies regarding their direct and indirect water use implies that there is still a long way to go before we can expect that companies effectively contribute to making water footprints more sustainable at a relevant scale.

  10. Water footprint of Ghana

    Science.gov (United States)

    Debrah, E. R.; Odai, S. N.; Annor, F. O.; Adjei, K. A.; van der Zaag, P.

    2009-04-01

    Water is used in almost all human endeavour. Unlike oil, water does not have a substitute. There are many factors that affect the water consumption pattern of people. These include climatic condition, income level and agricultural practices among others. The water footprint concept has been developed in order to have an indicator of water use in relation to its consumption by people. The water footprint of a country is defined as the volume of water needed for the production of the goods and services consumed by the inhabitants of the country (Chapagain and Hoekstra, 2008). Due to the bulky nature of water, it is not in its raw state a tradable commodity though it could be traded through the exchange of goods and services from one point to the other. Closely linked to the water footprint concept is the virtual water concept. Virtual water can be defined as the volume of water required to produce a commodity or service (Chapagain and Hoekstra, 2008 and Allan, 1999). The international trade of these commodities implies flows of virtual water over large distances. The water footprint of a nation can therefore be assessed by quantifying the use of domestic water resources, taking out the virtual water flow that leaves the country and adding the virtual water flow that enters the country to it. This research focuses on the assessment and analysis of the water footprints of Ghana considering only the consumptive component of the water footprint. In addition to livestock, 13 crops were considered, 4 of which were cash crops. Data was analysed for the year 2001 to 2005 The most recent framework for the analysis of water footprint is offered by Chapagain and Hoekstra. This was adopted for the study. The water footprint calculations show that the water footprint of Ghana is about 20011 Gm³/yr. Base on this the average water footprint of a Ghanaian is 823 m³/cap/yr. Not only agricultural crops but also other products require water for their manufacture, aluminium being a

  11. Exploratorium: Exploring Water.

    Science.gov (United States)

    Brand, Judith, Ed.

    2001-01-01

    This issue of Exploratorium focuses on water and its varied uses in our environment. Articles include: (1) "Adventures with Water" (Eric Muller); (2) "Water: The Liquid of Life" (Karen E. Kalumuck); (3) "Water-Drop Projector" (Gorazd Planinsic); (4) "Waterways and Means" (Pearl Tesler); (5) "Explore Natural Phenomena in the Museum--and Just…

  12. Urbanizing rural waters

    NARCIS (Netherlands)

    Hommes, Lena; Boelens, Rutgerd

    2017-01-01

    This article studies how urbanization processes and associated rural-urban water transfers in the Lima region (Peru) create water control hierarchies that align the municipal drinking water company, hydropower plants and rural communities on unequal positions. By scrutinizing the history of water tr

  13. Salt, Water, and Athletes.

    Science.gov (United States)

    Smith, Nathan J.

    Good nutrition for athletes demands plenty of water, since water is essential to such vital functions as muscle reactions. Dehydration can result from jet travel as well as from exercise and heat, making it a danger to traveling athletic teams. To avoid dehydration, water needs should be monitored by frequent weighing, and a clean water supply…

  14. Water, the intangible element

    NARCIS (Netherlands)

    Schotting, R.J.

    2009-01-01

    Water is the key to life. No living creature can survive without water. Too much water or polluted water are serious threats to mankind. Managing this intangible element is complex, not only in wet deltaic regions but also in the (semi-)arid regions of the world. Combined efforts of the hydro(geo)lo

  15. No Watered Down Solution

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Droughts and floods have plagued the Chinese people for the entire summer. Along with alarming news of toxic spills in rivers and polluted water, the current situation of China's water resources is extremely worrying. Threatened by global warming, water pollution and soil erosion, sustainable development in China is becoming more difficult to maintain as the precious water resources are threatened.

  16. Water and Something Else.

    Science.gov (United States)

    Hougendobler, Nancy

    Prepared for middle or intermediate grades, this student booklet provides a study of water--the location of major oceans and rivers; the relationship of ancient civilizations to bodies of water; active metals found in sea water; chemical concentrations in water and their effects on marine life; and the concepts of evaporation, transpiration,…

  17. Urbanizing rural waters

    NARCIS (Netherlands)

    Hommes, Lena; Boelens, Rutgerd

    2017-01-01

    This article studies how urbanization processes and associated rural-urban water transfers in the Lima region (Peru) create water control hierarchies that align the municipal drinking water company, hydropower plants and rural communities on unequal positions. By scrutinizing the history of water tr

  18. Water footprints of nations

    NARCIS (Netherlands)

    Chapagain, Ashok; Hoekstra, Arjen Ysbert

    The water footprint concept has been developed in order to have an indicator of water use in relation to consumption of people. The water footprint of a country is defined as the volume of water needed for the production of the goods and services consumed by the inhabitants of the country. Closely

  19. Potable water supply

    Science.gov (United States)

    Sauer, R. L.; Calley, D. J.

    1975-01-01

    The history and evolution of the Apollo potable water system is reviewed. Its operation in the space environment and in the spacecraft is described. Its performance is evaluated. The Apollo potable water system satisfied the dual purpose of providing metabolic water for the crewmen and water for spacecraft cooling.

  20. Water Management in Poland

    Directory of Open Access Journals (Sweden)

    Wojciech Majewski

    2015-03-01

    Full Text Available This paper presents the current situation in Polish water resources management. Discussed here are measures taken by the Ministry of Environment to introduce a new water law, as well as reforms of water management in Poland. The state of water resources in Poland are described, and the actions needed to improve this situation, taking into account possible climate changes and their impact on the use of water resources. Critically referred to is the introduction by the Ministry of Environment of charges for water abstraction by hydro power plants, and adverse effects for the energy and water management sectors are discussed.

  1. Water use in California

    Science.gov (United States)

    Brandt, Justin; Sneed, Michelle; Rogers, Laurel Lynn; Metzger, Loren F.; Rewis, Diane; House, Sally F.

    2014-01-01

    As part of the USGS National Water Use Compilation, the California Water Science Center works in cooperation with local, State, and Federal agencies as well as academic and private organizations to collect and report total water withdrawals for California. The 2010 California water use data are aggregated here, in this website, for the first time. The California Water Science Center released these data ahead of the online USGS National Water Use Compilation circular report, in response to increased interest associated with current drought conditions. The national report is expected to be released late in 2014. The data on this website represents the most current California water use data available in the USGS National Water Use Compilation. It contains a section on water use in California for 2010. Water-use estimates are compiled by withdrawal source type, use category, and county. Withdrawal source types include groundwater, both fresh and saline,

  2. Synthesis of ceramics membranes using ZrO{sub 2} obtained by Pechini method aiming it application in oil/water separation; Sintese de membranas ceramicas utilizando ZrO{sub 2} obtido pelo metodo Pechini visando sua aplicacao na separacao oleo/agua

    Energy Technology Data Exchange (ETDEWEB)

    Maia, D.F.; Lira, H.L.; Vilar, M.A.; Costa, A.C.F.M.; Oliveira, J.B.L.; Kiminami, R.H.G.A.; Gama, L.

    2004-07-01

    The water produced in the oil production presents emulsified oil drops of difficult separation causing problems in the reinjection and the discarding. The conventional methods used in the separation oil/water don't clean all the water with efficiency and low cost. Thus, the ceramic membranes appear as a new option for being material very resistant chemistry and thermal, of high perm selective and high efficiency in use in processes of micro filtration and ultrafiltration separation. The zirconia is considered an adequate material to obtain of such membranes and the Pechini method is one promising technique in the attainment of after ultrafine with controlled characteristics. Thus the objective of this work was to prepare ceramic membranes from after synthesized by the Pechini method. The results had shown that the Pechini method was efficient in the attainment of ZrO{sub 2} powder, nanometric, with size of crystal of 7,2 nm and with average diameter of agglomerated 4,94{mu}, indicating that this material can be used in the attainment of membranes of micro filtration and ultrafiltration, adjusted to the separation oil/water The micrographs of the obtained membranes show a homogeneous surface where if it can visualize pores uniformly distributed. (author)

  3. WATER FOOTPRINT IN HUNGARY

    OpenAIRE

    2012-01-01

    More and more news report on water-related extreme environmental phenomena. Some of these are natural, which are often beyond the human race. But others are definitely due to anthropogenic effects. I think the water footprint index is able to highlight national and international water-use processes and gives us the opportunity of organizing a sustainable, consumer-, environmental- and governancefriendly management. 81% of the fresh water withdrawal is from surface water bodies in the EU. In E...

  4. The global water cycle

    Science.gov (United States)

    Oki, Taikan; Entekhabi, Dara; Harrold, Timothy Ives

    The global water cycle consists of the oceans, water in the atmosphere, and water in the landscape. The cycle is closed by the fluxes between these reservoirs. Although the amounts of water in the atmosphere and river channels are relatively small, the fluxes are high, and this water plays a critical role in society, which is dependent on water as a renewable resource. On a global scale, the meridional component of river runoff is shown to be about 10% of the corresponding atmospheric and oceanic meridional fluxes. Artificial storages and water withdrawals for irrigation have significant impacts on river runoff and hence on the overall global water cycle. Fully coupled atmosphere-land-river-ocean models of the world's climate are essential to assess the future water resources and scarcities in relation to climate change. An assessment of future water scarcity suggests that water shortages will worsen, with a very significant increase in water stress in Africa. The impact of population growth on water stress is shown to be higher than that of climate change. The virtual water trade, which should be taken into account when discussing the global water cycle and water scarcity, is also considered. The movement of virtual water from North America, Oceania, and Europe to the Middle East, North West Africa, and East Asia represents significant global savings of water. The anticipated world water crisis widens the opportunities for the study of the global water cycle to contribute to the development of sustainability within society and to the solution of practical social problems.

  5. Ground water and energy

    Energy Technology Data Exchange (ETDEWEB)

    1980-11-01

    This national workshop on ground water and energy was conceived by the US Department of Energy's Office of Environmental Assessments. Generally, OEA needed to know what data are available on ground water, what information is still needed, and how DOE can best utilize what has already been learned. The workshop focussed on three areas: (1) ground water supply; (2) conflicts and barriers to ground water use; and (3) alternatives or solutions to the various issues relating to ground water. (ACR)

  6. REUSE OF WASTE WATER

    OpenAIRE

    Carvalho, Nathália Leal; Hentz,Paulo; Silva, Josemar Marques; Barcellos, Afonso Lopes

    2014-01-01

    http://dx.doi.org/10.5902/2236130812585Given that water is a limited natural resource essential to life, questions about the conservation and preservation of water resources has been the focus of studies by bodies which conservationists seek alternatives for better use of natural resources. The technologies use water solutions are sustainable and contribute to the rational use of water, providing the conservation of water resources for future generations. The continuous increase of the world ...

  7. Drinking water and cancer.

    OpenAIRE

    Morris, R D

    1995-01-01

    Any and all chemicals generated by human activity can and will find their way into water supplies. The types and quantities of carcinogens present in drinking water at the point of consumption will differ depending on whether they result from contamination of the source water, arise as a consequence of treatment processes, or enter as the water is conveyed to the user. Source-water contaminants of concern include arsenic, asbestos, radon, agricultural chemicals, and hazardous waste. Of these,...

  8. Drought Water Right Curtailment

    Science.gov (United States)

    Walker, W.; Tweet, A.; Magnuson-Skeels, B.; Whittington, C.; Arnold, B.; Lund, J. R.

    2016-12-01

    California's water rights system allocates water based on priority, where lower priority, "junior" rights are curtailed first in a drought. The Drought Water Rights Allocation Tool (DWRAT) was developed to integrate water right allocation models with legal objectives to suggest water rights curtailments during drought. DWRAT incorporates water right use and priorities with a flow-forecasting model to mathematically represent water law and hydrology and suggest water allocations among water rights holders. DWRAT is compiled within an Excel workbook, with an interface and an open-source solver. By implementing California water rights law as an algorithm, DWRAT provides a precise and transparent framework for the complicated and often controversial technical aspects of curtailing water rights use during drought. DWRAT models have been developed for use in the Eel, Russian, and Sacramento river basins. In this study, an initial DWRAT model has been developed for the San Joaquin watershed, which incorporates all water rights holders in the basin and reference gage flows for major tributaries. The San Joaquin DWRAT can assess water allocation reliability by determining probability of rights holders' curtailment for a range of hydrologic conditions. Forecasted flow values can be input to the model to provide decision makers with the ability to make curtailment and water supply strategy decisions. Environmental flow allocations will be further integrated into the model to protect and improve ecosystem water reliability.

  9. Water microbiology. Bacterial pathogens and water.

    Science.gov (United States)

    Cabral, João P S

    2010-10-01

    Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general characterization of the most important bacterial diseases transmitted through water-cholera, typhoid fever and bacillary dysentery-is presented, focusing on the biology and ecology of the causal agents and on the diseases' characteristics and their life cycles in the environment. The importance of pathogenic Escherichia coli strains and emerging pathogens in drinking water-transmitted diseases is also briefly discussed. Microbiological water analysis is mainly based on the concept of fecal indicator bacteria. The main bacteria present in human and animal feces (focusing on their behavior in their hosts and in the environment) and the most important fecal indicator bacteria are presented and discussed (focusing on the advantages and limitations of their use as markers). Important sources of bacterial fecal pollution of environmental waters are also briefly indicated. In the last topic it is discussed which indicators of fecal pollution should be used in current drinking water microbiological analysis. It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci. More studies are needed in order to check if ammonia is reliable for a preliminary screening for emergency fecal pollution outbreaks. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters.

  10. Ionic behavior of treated water at a water purification plant

    OpenAIRE

    Yanagida, Kazumi; Kawahigashi, Tatsuo

    2012-01-01

    [Abstract] Water at each processing stage in a water purification plant was extracted and analyzed to investigate changes of water quality. Investigations of water at each processing stage at the water purification plant are discussed herein.

  11. Ionic behavior of treated water at a water purification plant

    OpenAIRE

    Yanagida, Kazumi; Kawahigashi, Tatsuo

    2012-01-01

    [Abstract] Water at each processing stage in a water purification plant was extracted and analyzed to investigate changes of water quality. Investigations of water at each processing stage at the water purification plant are discussed herein.

  12. Paying for water.

    Science.gov (United States)

    Middleton, J; Saunders, P

    1997-03-01

    Water has been taken for granted as an essential public health need since the Victorian sanitary revolution. Water has come back on to the public health agenda in the United Kingdom because of recent policy changes and their untoward environmental and social impacts; along with water privatization and tough new environmental directives, there have been serious water pollution incidents, water shortages, water debt and disconnection. Along with concern about protecting individual rights to a clean safe water supply, there is concern about the ability of national water resources to meet all our communities' needs, without unacceptable environmental damage. A national plan is needed for the conservation of water and protection of water resources and the environment; adequate central funds are needed to see that this happens. There should be greater emphasis on local water management and a key role for local authorities; there should be fair pricing, protection of water supplies for the poorest and most vulnerable, and a ban on water disconnection to domestic users, on public health grounds. More research is needed into the potential adverse health impact of people on prepayment meters disconnecting themselves. There is a place for water metering as the most rapidly deliverable means of controlling peak demand, reducing overall consumption and avoiding a large-scale environmentally damaging solution to supply more water. However, control of leakage offers the largest potential saving and is the most cost-effective means to protect existing water supply. We question whether private water companies, geared to maximizing profit and share dividends, can deliver a national plan for the protection and management of water resources, for the good of the environment and future generations. The public health lobby must become more actively engaged in the debate about the supply, protection and price of our most precious public health asset-water.

  13. PREFACE: Water at interfaces Water at interfaces

    Science.gov (United States)

    Gallo, P.; Rovere, M.

    2010-07-01

    This special issue is devoted to illustrating important aspects and significant results in the field of modeling and simulation of water at interfaces with solutes or with confining substrates, focusing on a range of temperatures from ambient to supercooled. Understanding the behavior of water, in contact with different substrates and/or in solutions, is of pivotal importance for a wide range of applications in physics, chemistry and biochemistry. Simulations of confined and/or interfacial water are also relevant for testing how different its behavior is with respect to bulk water. Simulations and modeling in this field are of particular importance when studying supercooled regions where water shows anomalous properties. These considerations motivated the organization of a workshop at CECAM in the summer of 2009 which aimed to bring together scientists working with computer simulations on the properties of water in various environments with different methodologies. In this special issue, we collected a variety of interesting contributions from some of the speakers of the workshop. We have roughly classified the contributions into four groups. The papers of the first group address the properties of interfacial and confined water upon supercooling in an effort to understand the relation with anomalous behavior of supercooled bulk water. The second group deals with the specific problem of solvation. The next group deals with water in different environments by considering problems of great importance in technological and biological applications. Finally, the last group deals with quantum mechanical calculations related to the role of water in chemical processes. The first group of papers is introduced by the general paper of Stanley et al. The authors discuss recent progress in understanding the anomalies of water in bulk, nanoconfined, and biological environments. They present evidence that liquid water may display 'polymorphism', a property that can be present in

  14. Selected Works in Water Supply, Water Conservation and Water Quality Planning.

    Science.gov (United States)

    1981-05-01

    Reuse of water (unspecified) 3. Flushinb toilet with greywater 4. Reduce amount of water used per shower and/or bath 5. Reduce frequency of showers and/or...government, and has held training seminars on water supply and water conservation planning and on water reuse . A water supply and conservation...Planning 9 Water Reuse 9 Water Demand Forecast and Analysis 9 Drought Management 10 Water Conservation in Water Supply Planning 10 Urban Water Supply 11

  15. Water resources data, Kentucky. Water year 1991

    Energy Technology Data Exchange (ETDEWEB)

    McClain, D.L.; Byrd, F.D.; Brown, A.C.

    1991-12-31

    Water resources data for the 1991 water year for Kentucky consist of records of stage, discharge, and water quality of streams and lakes; and water-levels of wells. This report includes daily discharge records for 115 stream-gaging stations. It also includes water-quality data for 38 stations sampled at regular intervals. Also published are 13 daily temperature and 8 specific conductance records, and 85 miscellaneous temperature and specific conductance determinations for the gaging stations. Suspended-sediment data for 12 stations (of which 5 are daily) are also published. Ground-water levels are published for 23 recording and 117 partial sites. Precipitation data at a regular interval is published for 1 site. Additional water data were collected at various sites not involved in the systematic data-collection program and are published as miscellaneous measurement and analyses. These data represent that part of the National Water Data System operated by the US Geological Survey and cooperation State and Federal agencies in Kentucky.

  16. Water Entrainment in Concrete

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben

    This report gives a survey of different techniques for incorporation of designed, water-filled cavities in concrete: Water entrainment. Also an estimate of the optimum size of the water inclusions is given. Water entrainment can be used to avoid self-desiccation and self-desiccation shrinkage...... during hydration [1,26]. What is needed is some sort of container which retains the shape of the water when mixed into the concrete. The container may function based on several different physical or chemical principles. Cells and gels are examples of containers found in nature. A cell membrane provides...... a boundary to water, whereas a polymer network incorporates water in its intersticious space with its affinity due to interaction energy and polymer entropy. Such containers allow water to be stored as an entity. In relation to concrete the water encapsulation may be accomplished either before or after start...

  17. Water-transporting proteins

    DEFF Research Database (Denmark)

    Zeuthen, Thomas

    2010-01-01

    Transport through lipids and aquaporins is osmotic and entirely driven by the difference in osmotic pressure. Water transport in cotransporters and uniporters is different: Water can be cotransported, energized by coupling to the substrate flux by a mechanism closely associated with protein...... transport. Epithelial water transport is energized by the movements of ions, but how the coupling takes place is uncertain. All epithelia can transport water uphill against an osmotic gradient, which is hard to explain by simple osmosis. Furthermore, genetic removal of aquaporins has not given support...... to osmosis as the exclusive mode of transport. Water cotransport can explain the coupling between ion and water transport, a major fraction of transepithelial water transport and uphill water transport. Aquaporins enhance water transport by utilizing osmotic gradients and cause the osmolarity...

  18. Water Microbiology. Bacterial Pathogens and Water

    Directory of Open Access Journals (Sweden)

    João P. S. Cabral

    2010-10-01

    Full Text Available Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general characterization of the most important bacterial diseases transmitted through water—cholera, typhoid fever and bacillary dysentery—is presented, focusing on the biology and ecology of the causal agents and on the diseases’ characteristics and their life cycles in the environment. The importance of pathogenic Escherichia coli strains and emerging pathogens in drinking water-transmitted diseases is also briefly discussed. Microbiological water analysis is mainly based on the concept of fecal indicator bacteria. The main bacteria present in human and animal feces (focusing on their behavior in their hosts and in the environment and the most important fecal indicator bacteria are presented and discussed (focusing on the advantages and limitations of their use as markers. Important sources of bacterial fecal pollution of environmental waters are also briefly indicated. In the last topic it is discussed which indicators of fecal pollution should be used in current drinking water microbiological analysis. It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci. More studies are needed in order to check if ammonia is reliable for a preliminary screening for emergency fecal pollution outbreaks. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters.

  19. Emergency Disinfection of Drinking Water

    Science.gov (United States)

    How to boil and disinfect water to kill most disease-causing microorganisms during emergency situations where regular water service has been interrupted and local authorities recommend using only bottled water, boiled water, or disinfected water.

  20. Water: Too Precious to Waste.

    Science.gov (United States)

    National Geographic World, 1983

    1983-01-01

    Provides background information on many topics related to water. These include the water cycle, groundwater, fresh water, chemical wastes, water purification, river pollution, acid rain, and water conservation. Information is presented at an elementary level. (JM)

  1. Water: Too Precious to Waste.

    Science.gov (United States)

    National Geographic World, 1983

    1983-01-01

    Provides background information on many topics related to water. These include the water cycle, groundwater, fresh water, chemical wastes, water purification, river pollution, acid rain, and water conservation. Information is presented at an elementary level. (JM)

  2. Molecular water oxidation catalysis

    CERN Document Server

    Llobet, Antoni

    2014-01-01

    Photocatalytic water splitting is a promising strategy for capturing energy from the sun by coupling light harvesting and the oxidation of water, in order to create clean hydrogen fuel. Thus a deep knowledge of the water oxidation catalysis field is essential to be able to come up with useful energy conversion devices based on sunlight and water splitting. Molecular Water Oxidation Catalysis: A Key Topic for New Sustainable Energy Conversion Schemes presents a comprehensive and state-of-the-art overview of water oxidation catalysis in homogeneous phase, describing in detail the most importan

  3. Human Beings And Water

    OpenAIRE

    2016-01-01

    The writer of this paper on this writing is talking about the human beings and water. Water is one of the very fundamentally things that human beings need to keep their lives. Human beings sometimes do not realise that the water is very important for them because they actually cannot live their lives without the present of water. Human beings can keep their lives without rice, but cannot without water. For instances the use of water for human beings are domestic use, cooking, washing, bathing...

  4. Urban water interfaces

    Science.gov (United States)

    Gessner, M. O.; Hinkelmann, R.; Nützmann, G.; Jekel, M.; Singer, G.; Lewandowski, J.; Nehls, T.; Barjenbruch, M.

    2014-06-01

    Urban water systems consist of large-scale technical systems and both natural and man-made water bodies. The technical systems are essential components of urban infrastructure for water collection, treatment, storage and distribution, as well as for wastewater and runoff collection and subsequent treatment. Urban aquatic ecosystems are typically subject to strong human influences, which impair the quality of surface and ground waters, often with far-reaching impacts on downstream aquatic ecosystems and water users. The various surface and subsurface water bodies in urban environments can be viewed as interconnected compartments that are also extensively intertwined with a range of technical compartments of the urban water system. As a result, urban water systems are characterized by fluxes of water, solutes, gases and energy between contrasting compartments of a technical, natural or hybrid nature. Referred to as urban water interfaces, boundaries between and within these compartments are often specific to urban water systems. Urban water interfaces are generally characterized by steep physical and biogeochemical gradients, which promote high reaction rates. We hypothesize that they act as key sites of processes and fluxes with notable effects on overall system behaviour. By their very nature, urban water interfaces are heterogeneous and dynamic. Therefore, they increase spatial heterogeneity in urban areas and are also expected to contribute notably to the temporal dynamics of urban water systems, which often involve non-linear interactions and feedback mechanisms. Processes at and fluxes across urban water interfaces are complex and less well understood than within well-defined, homogeneous compartments, requiring both empirical investigations and new modelling approaches at both the process and system level. We advocate an integrative conceptual framework of the urban water system that considers interfaces as a key component to improve our fundamental

  5. Water-transporting proteins.

    Science.gov (United States)

    Zeuthen, Thomas

    2010-04-01

    Transport through lipids and aquaporins is osmotic and entirely driven by the difference in osmotic pressure. Water transport in cotransporters and uniporters is different: Water can be cotransported, energized by coupling to the substrate flux by a mechanism closely associated with protein. In the K(+)/Cl(-) and the Na(+)/K(+)/2Cl(-) cotransporters, water is entirely cotransported, while water transport in glucose uniporters and Na(+)-coupled transporters of nutrients and neurotransmitters takes place by both osmosis and cotransport. The molecular mechanism behind cotransport of water is not clear. It is associated with the substrate movements in aqueous pathways within the protein; a conventional unstirred layer mechanism can be ruled out, due to high rates of diffusion in the cytoplasm. The physiological roles of the various modes of water transport are reviewed in relation to epithelial transport. Epithelial water transport is energized by the movements of ions, but how the coupling takes place is uncertain. All epithelia can transport water uphill against an osmotic gradient, which is hard to explain by simple osmosis. Furthermore, genetic removal of aquaporins has not given support to osmosis as the exclusive mode of transport. Water cotransport can explain the coupling between ion and water transport, a major fraction of transepithelial water transport and uphill water transport. Aquaporins enhance water transport by utilizing osmotic gradients and cause the osmolarity of the transportate to approach isotonicity.

  6. Low water FGD technologies

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-11-15

    Conventional flue gas desulphurisation (FGD) systems require large supplies of water. Technologies which reduce water usage are becoming more important with the large number of FGD systems being installed in response to ever tightening emission regulations. Reducing water loss is particularly important in arid regions of the world. This report reviews commercial and near commercial low water FGD processes for coal-fired power plants, including dry, semi-dry and multi-pollutant technologies. Wet scrubbers, the most widely deployed FGD technology, account for around 10–15% of the water losses in power plants with water cooling systems. This figure is considerably higher when dry/air cooling systems are employed. The evaporative water losses can be reduced by some 40–50% when the flue gas is cooled before it enters the wet scrubber, a common practice in Europe and Japan. Technologies are under development to capture over 20% of the water in the flue gas exiting the wet scrubber, enabling the power plant to become a water supplier instead of a consumer. The semi-dry spray dry scrubbers and circulating dry scrubbers consume some 60% less water than conventional wet scrubbers. The commercial dry sorbent injection processes have the lowest water consumption, consuming no water, or a minimal amount if the sorbent needs hydrating or the flue gas is humidified to improve performance. Commercial multi-pollutant systems are available that consume no water.

  7. Smart Growth and Water

    Science.gov (United States)

    This page contains resources that communities can use to integrate green infrastructure into streets and neighborhoods to reduce stormwater runoff, use water more efficiently, and protect water from pollution.

  8. Project Weather and Water.

    Science.gov (United States)

    Hansen, Pal J. Kirkeby

    2000-01-01

    Introduces Project Weather and Water with the goal of developing and testing ideas of how to implement weather topics and water physics in an integrated way. Discusses teacher preparation, implementation, and evaluation of this project. (ASK)

  9. WaterHydro_LKBSPRE

    Data.gov (United States)

    Vermont Center for Geographic Information — The WaterHydro_LKBSPRE layer consists of drainage basins for water bodies of approximately five or more acres. The data was digitized from 1:24,000 (or 1:25,000)...

  10. Drink Water, Fight Fat?

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_165714.html Drink Water, Fight Fat? When you have it in place ... HealthDay News) -- If you choose a glass of water instead of a beer or a sugar-sweetened ...

  11. Water Safety (Recreational)

    Science.gov (United States)

    Playing in the water - whether swimming, boating or diving - can be fun. It can also be dangerous, especially for children. Being safe can ... injuries and drowning. To stay safe in the water Avoid alcohol when swimming or boating Wear a ...

  12. Drinking Water FAQ

    Science.gov (United States)

    ... your well Who should test your well Drinking Water FAQ Frequently Asked Questions General Where does my ... CDC's Private Wells page. Top of Page Public Water Systems What type of health issues can be ...

  13. Water on the Knee

    Science.gov (United States)

    ... your knee joint. Some people call this condition "water on the knee." A swollen knee may be ... Choose low-impact exercise. Certain activities, such as water aerobics and swimming, don't place continuous weight- ...

  14. Water exercise in pregnancy.

    Science.gov (United States)

    Katz, V L

    1996-08-01

    Exercise in the water offers several physiological advantages to the pregnant woman. The hydrostatic force of water pushes extravascular fluid into the vascular spaces, producing an increase in central blood volume that may lead to increased uterine blood flow. This force is proportional to the depth of immersion. The increase in blood volume is proportional to the woman's edema. A marked diuresis and natriuresis accompanies the fluid shifts. The buoyancy of water supports the pregnant women. Water is thermoregulating. Studies of pregnant women exercising in the water have shown less fetal heart rate changes in the water than on land in response to exertion. Pregnant women's heart rates and blood pressures during water exercise are lower than on land exercise, reflecting the immersion-induced increase in circulating blood volume. The physiology of water exercise offers some compensation for the physiological changes of exercise on land that may beneficially affect pregnancy.

  15. VT Water Classifications

    Data.gov (United States)

    Vermont Center for Geographic Information — The Vermont Water Quality Standards (VTWQS) are rules intended to achieve the goals of the Vermont Surface Water Strategy, as well as the objective of the federal...

  16. Water Quality Standards Handbook

    Science.gov (United States)

    The Water Quality Standards Handbook is a compilation of the EPA's water quality standards (WQS) program guidance including recommendations for states, authorized tribes, and territories in reviewing, revising, and implementing WQS.

  17. Private Water Districts

    Data.gov (United States)

    California Department of Resources — Private Water District boundaries are areas where private contracts provide water to the district in California. This database is designed as a regions polygon...

  18. Water Quality Monitoring Sites

    Data.gov (United States)

    Vermont Center for Geographic Information — Water Quality Monitoring Site identifies locations across the state of Vermont where water quality data has been collected, including habitat, chemistry, fish and/or...

  19. Water Quality Protection Charges

    Data.gov (United States)

    Montgomery County of Maryland — The Water Quality Protection Charge (WQPC) is a line item on your property tax bill. WQPC funds many of the County's clean water initiatives including: • Restoration...

  20. Clean Water Act

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Clean Water Act (CWA) establishes the basic structure for regulating discharges of pollutants into U.S. waters and regulating quality standards for surface...

  1. Urban water trajectories

    CERN Document Server

    Allen, Adriana; Hofmann, Pascale; Teh, Tse-Hui

    2017-01-01

    Water is an essential element in the future of cities. It shapes cities’ locations, form, ecology, prosperity and health. The changing nature of urbanisation, climate change, water scarcity, environmental values, globalisation and social justice mean that the models of provision of water services and infrastructure that have dominated for the past two centuries are increasingly infeasible. Conventional arrangements for understanding and managing water in cities are being subverted by a range of natural, technological, political, economic and social changes. The prognosis for water in cities remains unclear, and multiple visions and discourses are emerging to fill the space left by the certainty of nineteenth century urban water planning and engineering. This book documents a sample of those different trajectories, in terms of water transformations, option, services and politics. Water is a key element shaping urban form, economies and lifestyles, part of the ongoing transformation of cities. Cities are face...

  2. State Water Districts

    Data.gov (United States)

    California Department of Resources — State Water Project District boundaries are areas where state contracts provide water to the district in California. This database is designed as a regions polygon...

  3. Water resources (Chapter 5)

    CSIR Research Space (South Africa)

    Hobbs, Philip

    2016-01-01

    Full Text Available Water availability/supply for shale gas development (SGD) in the assessment study area is severely constrained. Surface water availability is generally low, with large areas of non-perennial, episodic and ephemeral streams experiencing very high...

  4. SDWISFED Drinking Water Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — SDWIS/FED is EPA's national regulatory compliance database for the drinking water program. It includes information on the nation's 160,000 public water systems and...

  5. Water Quality Analysis Simulation

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Water Quality analysis simulation Program, an enhancement of the original WASP. This model helps users interpret and predict water quality responses to natural...

  6. Water Quality Analysis Simulation

    Science.gov (United States)

    The Water Quality analysis simulation Program, an enhancement of the original WASP. This model helps users interpret and predict water quality responses to natural phenomena and man-made pollution for variious pollution management decisions.

  7. Alternative disinfectant water treatments

    Science.gov (United States)

    Alternative disinfestant water treatments are disinfestants not as commonly used by the horticultural industry. Chlorine products that produce hypochlorous acid are the main disinfestants used for treating irrigation water. Chlorine dioxide will be the primary disinfestant discussed as an alternativ...

  8. Virginia Water Central

    OpenAIRE

    Virginia Water Resources Research Center

    2011-01-01

    This newsletter features articles on water-related science, policy, and law. Distributed to state agency representatives, faculty, students and interested citizens, it aims to provide current information, statistics, news, and notices related to water resources in Virginia.

  9. Drinking Water Distribution Systems

    Science.gov (United States)

    Learn about an overview of drinking water distribution systems, the factors that degrade water quality in the distribution system, assessments of risk, future research about these risks, and how to reduce cross-connection control risk.

  10. Virtual water: Virtuous impact? : the unsteady state of virtual water

    NARCIS (Netherlands)

    Roth, D.; Warner, J.F.

    2008-01-01

    “Virtual water,” water needed for crop production, is now being mainstreamed in the water policy world. Relying on virtual water in the form of food imports is increasingly recommended as good policy for water-scarce areas. Virtual water globalizes discussions on water scarcity, ecological sustainab

  11. Recent California Water Transfers: Emerging Options in Water Management

    Science.gov (United States)

    1992-12-01

    where droughts endure long enough that water managers have opportunities and motivation to test innovative water management strategies . With literally...water demands expand. This serves to motivate examination and experimentation with novel water management strategies , such as water transfers. 10... management strategies to which water transfers can be applied. The latter part of the chapter identifies several additional types of water transfers

  12. Virtual water: Virtuous impact? : the unsteady state of virtual water

    NARCIS (Netherlands)

    Roth, D.; Warner, J.F.

    2008-01-01

    “Virtual water,” water needed for crop production, is now being mainstreamed in the water policy world. Relying on virtual water in the form of food imports is increasingly recommended as good policy for water-scarce areas. Virtual water globalizes discussions on water scarcity, ecological

  13. Water Resources Research supports water economics submissions

    Science.gov (United States)

    Griffin, Ronald C.

    2012-09-01

    AGU's international interdisciplinary journal Water Resources Research (WRR) publishes original contributions in hydrology; the physical, chemical, and biological sciences; and the social and policy sciences, including economics, systems analysis, sociology, and law. With the rising relevance of water economics and related social sciences, the editors of WRR continue to encourage submissions on economics and policy. WRR was originally founded in the mid 1960s by Walter Langbein and economist Allen Kneese. Several former WRR editors have been economists—including David Brookshire, Ron Cummings, and Chuck Howe—and many landmark articles in water economics have been published in WRR.

  14. Technology for Water Treatment (National Water Management)

    Science.gov (United States)

    1992-01-01

    The buildup of scale and corrosion is the most costly maintenance problem in cooling tower operation. Jet Propulsion Laboratory successfully developed a non-chemical system that not only curbed scale and corrosion, but also offered advantages in water conservation, cost savings and the elimination of toxic chemical discharge. In the system, ozone is produced by an on-site generator and introduced to the cooling tower water. Organic impurities are oxidized, and the dissolved ozone removes bacteria and scale. National Water Management, a NASA licensee, has installed its ozone advantage systems at some 200 cooling towers. Customers have saved money and eliminated chemical storage and discharge.

  15. Water-budget methods

    Science.gov (United States)

    Healy, Richard W.; Scanlon, Bridget R.

    2010-01-01

    A water budget is an accounting of water movement into and out of, and storage change within, some control volume. Universal and adaptable are adjectives that reflect key features of water-budget methods for estimating recharge. The universal concept of mass conservation of water implies that water-budget methods are applicable over any space and time scales (Healy et al., 2007). The water budget of a soil column in a laboratory can be studied at scales of millimeters and seconds. A water-budget equation is also an integral component of atmospheric general circulation models used to predict global climates over periods of decades or more. Water-budget equations can be easily customized by adding or removing terms to accurately portray the peculiarities of any hydrologic system. The equations are generally not bound by assumptions on mechanisms by which water moves into, through, and out of the control volume of interest. So water-budget methods can be used to estimate both diffuse and focused recharge, and recharge estimates are unaffected by phenomena such as preferential flow paths within the unsaturated zone. Water-budget methods represent the largest class of techniques for estimating recharge. Most hydrologic models are derived from a water-budget equation and can therefore be classified as water-budget models. It is not feasible to address all water-budget methods in a single chapter. This chapter is limited to discussion of the “residual” water-budget approach, whereby all variables in a water-budget equation, except for recharge, are independently measured or estimated and recharge is set equal to the residual. This chapter is closely linked with Chapter 3, on modeling methods, because the equations presented here form the basis of many models and because models are often used to estimate individual components in water-budget studies. Water budgets for streams and other surface-water bodies are addressed in Chapter 4. The use of soil-water budgets and

  16. Water Saving for Development

    Science.gov (United States)

    Zacharias, Ierotheos

    2013-04-01

    The project "Water Saving for Development (WaS4D)" is financed by European Territorial Cooperational Programme, Greece-Italy 2007-2013, and aims at developing issues on water saving related to improvement of individual behaviors and implementing innovative actions and facilities in order to harmonize policies and start concrete actions for a sustainable water management, making also people and stakeholders awake to water as a vital resource, strategic for quality of life and territory competitiveness. Drinkable water saving culture & behavior, limited water resources, water supply optimization, water resources and demand management, water e-service & educational e-tools are the key words of WaS4D. In this frame the project objectives are: • Definition of water need for domestic and other than domestic purposes: regional and territorial hydro-balance; • promotion of locally available resources not currently being used - water recycling or reuse and rainwater harvesting; • scientific data implementation into Informative Territorial System and publication of geo-referred maps into the institutional web sites, to share information for water protection; • participated review of the regulatory framework for the promotion of water-efficient devices and practices by means of the definition of Action Plans, with defined targets up to brief (2015) and medium (2020) term; • building up water e-services, front-office for all the water issues in building agricultural, industrial and touristic sectors, to share information, procedures and instruments for the water management; • creation and publication of a user friendly software, a game, to promote sustainability for houses also addressed to young people; • creation of water info point into physical spaces called "Water House" to promote education, training, events and new advisory services to assist professionals involved in water uses and consumers; • implementation of participatory approach & networking for a

  17. Save water, save money

    Science.gov (United States)

    ,; Fairfax County, VA

    1977-01-01

    The United States uses huge quantities of water. In 1976, for example, it was estimated that for each person in the U.S., about 2,000 gallons of water were used daily in homes, offices, farms, and factories. This means that roughly 420 billion gallons of water were pumped, piped, or diverted each day—about 15 percent more than in 1970. By the year 2000, our daily water needs will probably exceed 800 billion gallons.

  18. Exploding Water Drops

    Science.gov (United States)

    Reich, Gary

    2016-01-01

    Water has the unusual property that it expands on freezing, so that ice has a specific gravity of 0.92 compared to 1.0 for liquid water. The most familiar demonstration of this property is ice cubes floating in a glass of water. A more dramatic demonstration is the ice bomb shown in Fig. 1. Here a cast iron flask is filled with water and tightly…

  19. Water Policies of Turkey

    OpenAIRE

    Hakan Istanbulluoglu; Tayfun Kir

    2011-01-01

    Water is one of our most critical resources. Civilization has historically flourished around major waterways. The most important uses of water are; agricultural, industrial and domestic use. This critical resource is under threat around the world. In the next 20 years, the quantity of water available to everyone is predicted to decrease by 30%. 40% of the world\\\\\\\\\\\\\\'s inhabitants currently have insufficient fresh water for minimal hygiene. In 2000 more than 2.2 million people died from wate...

  20. Irrigation water quality assessments

    Science.gov (United States)

    Increasing demands on fresh water supplies by municipal and industrial users means decreased fresh water availability for irrigated agriculture in semi arid and arid regions. There is potential for agricultural use of treated wastewaters and low quality waters for irrigation but this will require co...

  1. Water at a crossroads

    Science.gov (United States)

    2013-01-01

    Climate and water expert Pavel Kabat -- director and CEO of the International Institute for Applied System Analysis in Austria -- calls for a long-term system approach to water research, new partnerships with the developing world and a change in donor practices, to tackle water-climate issues. He talks to Nature Climate Change.

  2. Water beheren en communiceren

    NARCIS (Netherlands)

    Lijklema, S.

    2001-01-01

    Nowadays, information and communication with the public are self-evident for water authorities. Its aim is often formulated as 'creating or strengthening public support' for water management or for the water authorities. A lot of time and money is being spent on this, while the necessity of having p

  3. Grey water biodegradability

    NARCIS (Netherlands)

    Abu Ghunmi, L.; Zeeman, G.; Fayyad, M.; Lier, van J.B.

    2011-01-01

    Knowing the biodegradability characteristics of grey water constituents is imperative for a proper design and operation of a biological treatment system of grey water. This study characterizes the different COD fractions of dormitory grey water and investigates the effect of applying different condi

  4. PROPERTIES OF SWIMMING WATER

    Directory of Open Access Journals (Sweden)

    Tayfun KIR

    2004-10-01

    Full Text Available Swimming waters may be hazardous on human health. So, The physicians who work in the facilities, which include swimming areas, are responsible to prevent risks. To ensure hygiene of swimming water, European Swimming Water Directive offers microbiological, physical, and chemical criteria. [TAF Prev Med Bull 2004; 3(5.000: 103-104

  5. PROPERTIES OF SWIMMING WATER

    OpenAIRE

    Tayfun KIR; Zakir COBANOÐLU

    2004-01-01

    Swimming waters may be hazardous on human health. So, The physicians who work in the facilities, which include swimming areas, are responsible to prevent risks. To ensure hygiene of swimming water, European Swimming Water Directive offers microbiological, physical, and chemical criteria. [TAF Prev Med Bull 2004; 3(5.000): 103-104

  6. Shallow-Water Propagation

    Science.gov (United States)

    2016-06-07

    Shallow- Water Propagation William L. Siegmann Rensselaer Polytechnic Institute 110 Eighth Street Troy, New York 12180-3590 phone: (518) 276...ocean_acoustics LONG-TERM GOALS Develop methods for propagation and coherence calculations in complex shallow- water environments, determine...intensity and coherence. APPROACH (A) Develop high accuracy PE techniques for applications to shallow- water sediments, accounting for

  7. Electrically excited liquid water

    NARCIS (Netherlands)

    Wexler, A.D.

    2016-01-01

    Water is essential to a healthy and secure world. Developing new technologies which can take full advantage of the unique attributes of water is important for meeting the ever increasing global demand while reducing the production footprint. Water exhibits unexpected departures in more than 70

  8. Growing Water Pearls

    Science.gov (United States)

    Milner-Bolotin, Marina

    2012-01-01

    Science teachers can find lesson ideas almost anywhere. For example, during a recent visit to a local dollar store, the author stumbled upon a flower vase filled with water pearls, also known as water beads and jelly beans. She bought several of the bags (search the web to find numerous online sources), and soon began experimenting. Water pearls…

  9. Quality of Drinking Water

    Science.gov (United States)

    Roman, Harry T.

    2009-01-01

    The quality of drinking water has been gaining a great deal of attention lately, especially as water delivery infrastructure continues to age. Particles of various metals such as lead and copper, and other substances like radon and arsenic could be entering drinking water supplies. Spilled-on-the-ground hydrocarbon-based substances are also…

  10. Water Conservation Resource List.

    Science.gov (United States)

    NJEA Review, 1981

    1981-01-01

    Alarmed by the growing water shortage, the New Jersey State Office of Dissemination has prepared this annotated list of free or inexpensive instructional materials for teaching about water conservation, K-l2. A tipsheet for home water conservation is appended. (Editor/SJL)

  11. Nickel in tap water

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Nielsen, G D; Flyvholm, Morten

    1983-01-01

    Nickel analyses of tap water from several sources in Copenhagen gave up to 490 X 10(-6) g X 1(-1) in the first 250 ml portions. Hot water gave higher values than cold water. After flushing for 5 min, low values were found. Considerable variation from time to time and from tap to tap was found...

  12. Electrically excited liquid water

    NARCIS (Netherlands)

    Wexler, A.D.

    2016-01-01

    Water is essential to a healthy and secure world. Developing new technologies which can take full advantage of the unique attributes of water is important for meeting the ever increasing global demand while reducing the production footprint. Water exhibits unexpected departures in more than 70 physi

  13. Quality of Drinking Water

    Science.gov (United States)

    Roman, Harry T.

    2009-01-01

    The quality of drinking water has been gaining a great deal of attention lately, especially as water delivery infrastructure continues to age. Particles of various metals such as lead and copper, and other substances like radon and arsenic could be entering drinking water supplies. Spilled-on-the-ground hydrocarbon-based substances are also…

  14. Nickel in tap water

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Nielsen, G D; Flyvholm, Morten

    1983-01-01

    Nickel analyses of tap water from several sources in Copenhagen gave up to 490 X 10(-6) g X 1(-1) in the first 250 ml portions. Hot water gave higher values than cold water. After flushing for 5 min, low values were found. Considerable variation from time to time and from tap to tap was found...

  15. Grey water biodegradability

    NARCIS (Netherlands)

    Abu Ghunmi, L.; Zeeman, G.; Fayyad, M.; Van Lier, J.B.

    2010-01-01

    Knowing the biodegradability characteristics of grey water constituents is imperative for a proper design and operation of a biological treatment system of grey water. This study characterizes the different COD fractions of dormitory grey water and investigates the effect of applying different condi

  16. NASA Water Resources Program

    Science.gov (United States)

    Toll, David L.

    2011-01-01

    With increasing population pressure and water usage coupled with climate variability and change, water issues are being reported by numerous groups as the most critical environmental problems facing us in the 21st century. Competitive uses and the prevalence of river basins and aquifers that extend across boundaries engender political tensions between communities, stakeholders and countries. In addition to the numerous water availability issues, water quality related problems are seriously affecting human health and our environment. The potential crises and conflicts especially arise when water is competed among multiple uses. For example, urban areas, environmental and recreational uses, agriculture, and energy production compete for scarce resources, not only in the Western U.S. but throughout much of the U.S. and also in numerous parts of the world. Mitigating these conflicts and meeting water demands and needs requires using existing water resources more efficiently. The NASA Water Resources Program Element works to use NASA products and technology to address these critical water issues. The primary goal of the Water Resources is to facilitate application of NASA Earth science products as a routine use in integrated water resources management for the sustainable use of water. This also includes the extreme events of drought and floods and the adaptation to the impacts from climate change. NASA satellite and Earth system observations of water and related data provide a huge volume of valuable data in both near-real-time and extended back nearly 50 years about the Earth's land surface conditions such as precipitation, snow, soil moisture, water levels, land cover type, vegetation type, and health. NASA Water Resources Program works closely to use NASA and Earth science data with other U.S. government agencies, universities, and non-profit and private sector organizations both domestically and internationally. The NASA Water Resources Program organizes its

  17. Water Fluoridation Reporting System (Public Water Systems)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Water Fluoridation Reporting System (WFRS) has been developed to provide tools to assist states in managing fluoridation programs. WFRS is designed to track all...

  18. Water and poverty: Implications for water planning

    Science.gov (United States)

    Fass, S. M.

    1993-07-01

    Although it recognizes the tangible economic benefits to health and income that may derive from greater safety of supply and improved time savings in procurement, planning for improvements of urban water systems in developing countries has overlooked other ways in which water may influence health and income among the poor. In these populations the price of water may further affect health and labor productivity, both directly through its impact on nutrition and indirectly through its impact on housing size and quality and on residential density. What at first might seem a straightforward equity issue in planning may thus be an issue of economic efficiency as well. Failure to account for the fuller range of tangible benefits associated with improvements in water supply may lead to underestimation of returns to investment and therefore to economically inefficient investment.

  19. Virtual scarce water in China.

    Science.gov (United States)

    Feng, Kuishuang; Hubacek, Klaus; Pfister, Stephan; Yu, Yang; Sun, Laixiang

    2014-07-15

    Water footprints and virtual water flows have been promoted as important indicators to characterize human-induced water consumption. However, environmental impacts associated with water consumption are largely neglected in these analyses. Incorporating water scarcity into water consumption allows better understanding of what is causing water scarcity and which regions are suffering from it. In this study, we incorporate water scarcity and ecosystem impacts into multiregional input-output analysis to assess virtual water flows and associated impacts among 30 provinces in China. China, in particular its water-scarce regions, are facing a serious water crisis driven by rapid economic growth. Our findings show that inter-regional flows of virtual water reveal additional insights when water scarcity is taken into account. Consumption in highly developed coastal provinces is largely relying on water resources in the water-scarce northern provinces, such as Xinjiang, Hebei, and Inner Mongolia, thus significantly contributing to the water scarcity in these regions. In addition, many highly developed but water scarce regions, such as Shanghai, Beijing, and Tianjin, are already large importers of net virtual water at the expense of water resource depletion in other water scarce provinces. Thus, increasingly importing water-intensive goods from other water-scarce regions may just shift the pressure to other regions, but the overall water problems may still remain. Using the water footprint as a policy tool to alleviate water shortage may only work when water scarcity is taken into account and virtual water flows from water-poor regions are identified.

  20. What is water?

    Science.gov (United States)

    ,

    1965-01-01

    If a schoolboy asked this question, you would answer it easily enough. "Why, water is a liquid found in and around the earth. Water is the sea, lakes, streams, springs and what comes gushing out of the tap when we turn it on." If he still looks a little unsatisfied, you would explain that our bodies are three-fourths water, and that water covers threefourths of the earth's surface. But you would have to admit to yourself that these facts, interesting as they are, do not quite answer the boy's question: "What is water?"

  1. Health and Water

    CSIR Research Space (South Africa)

    Genthe, Bettina

    2006-01-01

    Full Text Available , bacteria, parasites and toxins, and it is a symptom of many of the illness caused by the various pathogens that might be involved in water-related disease. Non-specific diarrhoeal disease is more frequent and causes more deaths globally than cholera...-borne, water-washed, water-vectored or water-based diseases. Among the most typical water-related disease are gastroenteritis, amoebiasis, salmonellosis, dysentery, cholera, typhoid fever and hepatitis. Although there has been a general decline...

  2. Wood–water interactions

    DEFF Research Database (Denmark)

    Engelund, Emil Tang

    2011-01-01

    must first know in which parts of the wood structure, water is located. If parts of the water in wood are held in capillaries in the wood structure, these water molecules interact with the material differently than those held within wood cell walls. In this study, the occurrence of capillary water......, for wood in equilibrium with surrounding climate in the RH range 0-99.5 %, water is only significantly present within cell walls. A structural model of a wood cell is developed in this study using Finite Element Method for predicting the mechanical performance of wood. The starting point for the model...... is the physical behaviour on the molecular level since water interferes with wood at this level. The elastic material properties of the wood cell wall are explained by the organisation of wood constituents and their properties. The effect of water as well as temperature is incorporated by considering the amount...

  3. Nitrate in drinking water

    DEFF Research Database (Denmark)

    Schullehner, Jörg; Hansen, Birgitte; Sigsgaard, Torben

    Annual nationwide exposure maps for nitrate in drinking water in Denmark from the 1970s until today will be presented based on the findings in Schullehner & Hansen (2014) and additional work on addressing the issue of private well users and estimating missing data. Drinking water supply in Denmark...... is highly decentralized and fully relying on simple treated groundwater. At the same time, Denmark has an intensive agriculture, making groundwater resources prone to nitrate pollution. Drinking water quality data covering the entire country for over 35 years are registered in the public database Jupiter....... In order to create annual maps of drinking water quality, these data had to be linked to 2,852 water supply areas, which were for the first time digitized, collected in one dataset and connected to the Jupiter database. Analyses of the drinking water quality maps showed that public water supplies...

  4. Dying for water.

    Science.gov (United States)

    Yeboah-afari, A

    1993-01-01

    In Danchira village in Ghana for the last 5 years, women and children rise before dawn every day to fetch water from a tributary or the River Densu, which is 5 miles from the village. Diminished rainfall has dried the village's 3 ponds and bore-hole where the women and children used to fetch water. To exacerbate the water problem, the Ghana Water and Sewerage Corporation no longer comes to fill the huge water tank it brought to Danchira when water scarcity first occurred. The villagers could not afford to pay for the water. A 55-year-old mother of 5, Dede Aryehteye, takes her morning bath at the river. When she has dirty laundry, she cleans it in the river. She returns to the village around 8 am. She uses the next hour to filter the dark water 2 times with a device provided free of charge by the national Guinea Worm Eradication Programme to keep the larvae out of the water. Next she sort the water for 3 uses: drinking, household use, and evening bath. Dede then does other domestic chores. She would rather go to her cassava farm in the early morning when it is cool but has to fetch water instead. When she is not too tired and after finishing domestic chores, she goes to the farm. Water-fetching also exhausts the children and gets them to school rather late. Children make up the majority of the 500 people living in Danchira. Water scarcity forced most of the young villagers to flee to the cities. For example, Dede's 4 older children now live in Accra. The water scarcity keeps the farmers from growing maize, cassava, and vegetables.

  5. Drinking water quality assessment.

    Science.gov (United States)

    Aryal, J; Gautam, B; Sapkota, N

    2012-09-01

    Drinking water quality is the great public health concern because it is a major risk factor for high incidence of diarrheal diseases in Nepal. In the recent years, the prevalence rate of diarrhoea has been found the highest in Myagdi district. This study was carried out to assess the quality of drinking water from different natural sources, reservoirs and collection taps at Arthunge VDC of Myagdi district. A cross-sectional study was carried out using random sampling method in Arthunge VDC of Myagdi district from January to June,2010. 84 water samples representing natural sources, reservoirs and collection taps from the study area were collected. The physico-chemical and microbiological analysis was performed following standards technique set by APHA 1998 and statistical analysis was carried out using SPSS 11.5. The result was also compared with national and WHO guidelines. Out of 84 water samples (from natural source, reservoirs and tap water) analyzed, drinking water quality parameters (except arsenic and total coliform) of all water samples was found to be within the WHO standards and national standards.15.48% of water samples showed pH (13) higher than the WHO permissible guideline values. Similarly, 85.71% of water samples showed higher Arsenic value (72) than WHO value. Further, the statistical analysis showed no significant difference (Pwater for collection taps water samples of winter (January, 2010) and summer (June, 2010). The microbiological examination of water samples revealed the presence of total coliform in 86.90% of water samples. The results obtained from physico-chemical analysis of water samples were within national standard and WHO standards except arsenic. The study also found the coliform contamination to be the key problem with drinking water.

  6. Ground water in Oklahoma

    Science.gov (United States)

    Leonard, A.R.

    1960-01-01

    One of the first requisites for the intelligent planning of utilization and control of water and for the administration of laws relating to its use is data on the quantity, quality, and mode of occurrence of the available supplies. The collection, evaluation and interpretation, and publication of such data are among the primary functions of the U.S. Geological Survey. Since 1895 the Congress has made appropriations to the Survey for investigation of the water resources of the Nation. In 1929 the Congress adopted the policy of dollar-for-dollar cooperation with the States and local governmental agencies in water-resources investigations of the U.S. Geological Survey. In 1937 a program of ground-water investigations was started in cooperation with the Oklahoma Geological Survey, and in 1949 this program was expanded to include cooperation with the Oklahoma Planning and Resources Board. In 1957 the State Legislature created the Oklahoma Water Resources Board as the principal State water agency and it became the principal local cooperator. The Ground Water Branch of the U.S. Geological Survey collects, analyzes, and evaluates basic information on ground-water resources and prepares interpretive reports based on those data. Cooperative ground-water work was first concentrated in the Panhandle counties. During World War II most work was related to problems of water supply for defense requirements. Since 1945 detailed investigations of ground-water availability have been made in 11 areas, chiefly in the western and central parts of the State. In addition, water levels in more than 300 wells are measured periodically, principally in the western half of the State. In Oklahoma current studies are directed toward determining the source, occurrence, and availability of ground water and toward estimating the quantity of water and rate of replenishment to specific areas and water-bearing formations. Ground water plays an important role in the economy of the State. It is

  7. Water Recycling in Australia

    Directory of Open Access Journals (Sweden)

    Ross Young

    2011-09-01

    Full Text Available Australia is the driest inhabited continent on earth and, more importantly, experiences the most variable rainfall of all the continents on our planet. The vast majority of Australians live in large cities on the coast. Because wastewater treatments plants were all located near the coast, it was thought that large scale recycling would be problematic given the cost of infrastructure and pumping required to establish recycled water schemes. This all changed when Australia experienced a decade of record low rainfall and water utilities were given aggressive targets to increase the volume of water recycled. This resulted in recycled water being accepted as a legitimate source of water for non-drinking purposes in a diversified portfolio of water sources to mitigate climate risk. To ensure community support for recycled water, Australia lead the world in developing national guidelines for the various uses of recycled water to ensure the protection of public health and the environment. Australia now provides a great case study of the developments in maximizing water recycling opportunities from policy, regulatory and technological perspectives. This paper explores the evolution in thinking and how approaches to wastewater reuse has changed over the past 40 years from an effluent disposal issue to one of recognizing wastewater as a legitimate and valuable resource. Despite recycled water being a popular choice and being broadly embraced, the concept of indirect potable reuse schemes have lacked community and political support across Australia to date.

  8. Water en Land

    Directory of Open Access Journals (Sweden)

    P.J.E.M. van Dam

    2009-01-01

    Full Text Available Water and Dry LandWater management has always been a major concern. Dutch pragmatism certainly has roots in water management, but it is also rooted in the culture of meetings of the Dutch cities and in the attitude of the peasant who produced for the market very early on. Water control reached its height when we introduced reinforced concrete for hydraulic engineering. Around 1970, the ecological turning point caused a change in focus. Water managers became concerned about the quality of water, the creation of ‘new nature’ and the adaptation to water. In this way, we did not discard the assets of the Industrial Revolution, but rather put them into a new framework: more green in the blue. Water is by definition international. The Netherlands co-parented the international cooperation of the Rhine countries. Is this history part of our national consciousness? Can the water history of the South- and Eastern Netherlands also join in the national water history of the twentieth century?

  9. Water en Land

    Directory of Open Access Journals (Sweden)

    P.J.E.M. van Dam

    2009-01-01

    Full Text Available Water and Dry LandWater management has always been a major concern. Dutch pragmatism certainly has roots in water management, but it is also rooted in the culture of meetings of the Dutch cities and in the attitude of the peasant who produced for the market very early on. Water control reached its height when we introduced reinforced concrete for hydraulic engineering. Around 1970, the ecological turning point caused a change in focus. Water managers became concerned about the quality of water, the creation of ‘new nature’ and the adaptation to water. In this way, we did not discard the assets of the Industrial Revolution, but rather put them into a new framework: more green in the blue. Water is by definition international. The Netherlands co-parented the international cooperation of the Rhine countries. Is this history part of our national consciousness? Can the water history of the South- and Eastern Netherlands also join in the national water history of the twentieth century?

  10. Water Footprint and Virtual Water Trade of Brazil

    Directory of Open Access Journals (Sweden)

    Vicente de Paulo R. da Silva

    2016-11-01

    Full Text Available Freshwater scarcity has increased at an alarming rate worldwide; improved water management plays a vital role in increasing food production and security. This study aims to determine the water footprint of Brazil’s national food consumption, the virtual water flows associated with international trade in the main agricultural commodities, as well as water scarcity, water self-sufficiency and water dependency per Brazilian region. While previous country studies on water footprints and virtual water trade focused on virtual water importers or water-scarce countries, this is the first study to concentrate on a water-abundant virtual water-exporting country. Besides, it is the first study establishing international virtual water trade balances per state, which is relevant given the fact that water scarcity varies across states within the country, so the origin of virtual water exports matters. The results show that the average water footprint of Brazilian food consumption is 1619 m3/person/year. Beef contributes most (21% to this total. We find a net virtual water export of 54.8 billion m3/year, mainly to Europe, which imports 41% of the gross amount of the virtual water exported from Brazil. The northeast, the region with the highest water scarcity, has a net import of virtual water. The southeast, next in terms of water scarcity, shows large virtual water exports, mainly related to the export of sugar. The north, which has the most water, does not show a high virtual water export rate.

  11. Quantifying Water Stress Using Total Water Volumes and GRACE

    Science.gov (United States)

    Richey, A. S.; Famiglietti, J. S.; Druffel-Rodriguez, R.

    2011-12-01

    Water will follow oil as the next critical resource leading to unrest and uprisings globally. To better manage this threat, an improved understanding of the distribution of water stress is required today. This study builds upon previous efforts to characterize water stress by improving both the quantification of human water use and the definition of water availability. Current statistics on human water use are often outdated or inaccurately reported nationally, especially for groundwater. This study improves these estimates by defining human water use in two ways. First, we use NASA's Gravity Recovery and Climate Experiment (GRACE) to isolate the anthropogenic signal in water storage anomalies, which we equate to water use. Second, we quantify an ideal water demand by using average water requirements for the domestic, industrial, and agricultural water use sectors. Water availability has traditionally been limited to "renewable" water, which ignores large, stored water sources that humans use. We compare water stress estimates derived using either renewable water or the total volume of water globally. We use the best-available data to quantify total aquifer and surface water volumes, as compared to groundwater recharge and surface water runoff from land-surface models. The work presented here should provide a more realistic image of water stress by explicitly quantifying groundwater, defining water availability as total water supply, and using GRACE to more accurately quantify water use.

  12. What's in Your Water? An Educator's Guide to Water Quality.

    Science.gov (United States)

    Constabile, Kerry, Comp.; Craig, Heidi, Comp.; O'Laughlin, Laura, Comp.; Reiss, Anne Bei, Comp.; Spencer, Liz, Comp.

    This guide provides basic information on the Clean Water Act, watersheds, and testing for water quality, and presents four science lesson plans on water quality. Activities include: (1) "Introduction to Water Quality"; (2) "Chemical Water Quality Testing"; (3) "Biological Water Quality Testing"; and (4) "What Can We Do?" (YDS)

  13. Study of Water Jet Impulse in Water-Jet Looms

    Institute of Scientific and Technical Information of China (English)

    LI Ke-rang; MA Wei-wei; CHEN Ming

    2005-01-01

    The water jet impulse is brought forward to study the traction force of the water jet to the flying weft in water-jet looms. The distribution of the water jet impulse in the shed is tested by a sensor, and the influence of water jet parameters on the water jet impulse is analyzed.

  14. Water and wars

    Science.gov (United States)

    Gleick, Peter H.

    In “Challenging the Rhetoric of Water Wars” (Eos, In Brief, September 5, 2000, p. 410) Randy Showstack reported on the speech given by Minister Kader Asmal upon receiving the 2000 Stockholm Water Prize. This prize was well deserved for the tremendous progress South Africa has made under Minister Asmal's leadership in addressing basic water needs after apartheid. Indeed, I was one of his nominators for this prize and am an ardent fan of his bold programs. But his remarks about water-related conflicts need to be qualified. In his speech, Minister Asmal noted that water scarcity is a “crisis of biblical proportion,” but also suggested “there is not a shred of evidence” to back up arguments that there are water “wars.”

  15. Arsenic removal from water

    Science.gov (United States)

    Moore, Robert C.; Anderson, D. Richard

    2007-07-24

    Methods for removing arsenic from water by addition of inexpensive and commonly available magnesium oxide, magnesium hydroxide, calcium oxide, or calcium hydroxide to the water. The hydroxide has a strong chemical affinity for arsenic and rapidly adsorbs arsenic, even in the presence of carbonate in the water. Simple and commercially available mechanical methods for removal of magnesium hydroxide particles with adsorbed arsenic from drinking water can be used, including filtration, dissolved air flotation, vortex separation, or centrifugal separation. A method for continuous removal of arsenic from water is provided. Also provided is a method for concentrating arsenic in a water sample to facilitate quantification of arsenic, by means of magnesium or calcium hydroxide adsorption.

  16. Great Zimbabwe's water

    DEFF Research Database (Denmark)

    Pikirayi, Innocent; Sulas, Federica; Musindo, Tendai Treddah

    2016-01-01

    in the region's well-watered granite hills and valleys, and culminating in a vast urban and trading society. Later, c.1550 AD, it is argued, drying climate, land overexploitation, and changing regional trading patterns would lead to the decline of Great Zimbabwe. A review of this model is necessary since Great...... Zimbabwe and communities living around it survive in a region constantly threatened by water crises. However, we still know very little on the forms and uses of water and how these have influenced its development and demise. This article offers a multilayered review of available information on water......, including new records on environmental sequences, modern water sources, and provisioning models from in and around Great Zimbabwe. The integration of both old and new datasets allows us to follow the history of people-water interaction from early times to the present. We argue that understanding...

  17. Water transport in brain:

    DEFF Research Database (Denmark)

    MacAulay, Nanna; Hamann, Steffan; Zeuthen, Thomas

    2004-01-01

    It is generally accepted that cotransporters transport water in addition to their normal substrates, although the precise mechanism is debated; both active and passive modes of transport have been suggested. The magnitude of the water flux mediated by cotransporters may well be significant: both...... the number of cotransporters per cell and the unit water permeability are high. For example, the Na(+)-glutamate cotransporter (EAAT1) has a unit water permeability one tenth of that of aquaporin (AQP) 1. Cotransporters are widely distributed in the brain and participate in several vital functions: inorganic......(+)-lactate cotransporters. We have previously determined water transport capacities for these cotransporters in model systems (Xenopus oocytes, cell cultures, and in vitro preparations), and will discuss their role in water homeostasis of the astroglial cell under both normo- and pathophysiologal situations. Astroglia...

  18. Iodine mineral waters

    Directory of Open Access Journals (Sweden)

    Iluta Alexandru

    2011-11-01

    Full Text Available Iodine mineral waters are found especially in sub-Carpathian region, also in regions with Salif deposits. Waters are currently used iodine in drinking cure for chaps and Basedow. Are also indicated in balneology. Iodine water containing at least 1 mg L, there is pure iodine is usually given the nature of other types of mineral waters further: sodium chlorinated water (Bazna (50-70 mg iodine / l, Baile Govora (50 - 70 mg / l, Bălţăteşti (4-5 mg / l, salted Monteoru (30 mg / l, mine water mixed alkaline chlorination, sulphate, which are indicated for crenoterapie (hypo or isotonic to the bathrooms Olăneşti or Călimăneşti-Căciulata.

  19. Water hammer research in networks

    OpenAIRE

    Anželika Jurkienė; Mindaugas Rimeika

    2015-01-01

    Formation of water hammer, its consequences and possible protection measures are rarely topics, however the problem is significant. Water hammer can form in water supply and pressurized sewage networks, for various reasons. The article presents short theory of water hammer and methodology for calculation of specific parameters. Research of water hammer was performed in real water supply and sewer networks of country. Simulation of water hammer was carried out by turning on and off water pumps...

  20. Lithium content in potable water, surface water, ground water, and mineral water on the territory of Republic of Macedonia

    OpenAIRE

    Vesna Kostik; Biljana Bauer; Zoran Kavrakovski

    2014-01-01

    The aim of this study was to determine lithium concentration in potable water, surface water, ground, and mineral water on the territory of the Republic of Macedonia. Water samples were collected from water bodies such as multiple public water supply systems located in 13 cities, wells boreholes located in 12 areas, lakes and rivers located in three different areas. Determination of lithium concentration in potable water, surface water was performed by the technique of inductively coupl...

  1. Amniotic fluid water dynamics.

    Science.gov (United States)

    Beall, M H; van den Wijngaard, J P H M; van Gemert, M J C; Ross, M G

    2007-01-01

    Water arrives in the mammalian gestation from the maternal circulation across the placenta. It then circulates between the fetal water compartments, including the fetal body compartments, the placenta and the amniotic fluid. Amniotic fluid is created by the flow of fluid from the fetal lung and bladder. A major pathway for amniotic fluid resorption is fetal swallowing; however in many cases the amounts of fluid produced and absorbed do not balance. A second resorption pathway, the intramembranous pathway (across the amnion to the fetal circulation), has been proposed to explain the maintenance of normal amniotic fluid volume. Amniotic fluid volume is thus a function both of the amount of water transferred to the gestation across the placental membrane, and the flux of water across the amnion. Membrane water flux is a function of the water permeability of the membrane; available data suggests that the amnion is the structure limiting intramembranous water flow. In the placenta, the syncytiotrophoblast is likely to be responsible for limiting water flow across the placenta. In human tissues, placental trophoblast membrane permeability increases with gestational age, suggesting a mechanism for the increased water flow necessary in late gestation. Membrane water flow can be driven by both hydrostatic and osmotic forces. Changes in both osmotic/oncotic and hydrostatic forces in the placenta my alter maternal-fetal water flow. A normal amniotic fluid volume is critical for normal fetal growth and development. The study of amniotic fluid volume regulation may yield important insights into the mechanisms used by the fetus to maintain water homeostasis. Knowledge of these mechanisms may allow novel treatments for amniotic fluid volume abnormalities with resultant improvement in clinical outcome.

  2. Deep Water Ocean Acoustics

    Science.gov (United States)

    2016-04-30

    OASIS, INC. 1 Report No. QSR-14C0172-Ocean Acoustics-043016 Quarterly Progress Report Technical and Financial Deep Water Ocean Acoustics...understanding of the impact of the ocean and seafloor environmental variability on deep- water (long-range) ocean acoustic propagation and to...improve our understanding. During the past few years, the physics effects studied have been three-dimensional propagation on global scales, deep water

  3. Water recovery from dew

    OpenAIRE

    Nikolayev, Vadim; Beysens, D; Gioda, A; Milimouk, I; Katiushin, E; Morel, J.-P

    1996-01-01

    International audience; The recovery of clean water from dew has remained a longstanding challenge in many places all around the world. It is currently believed that the ancient Greeks succeeded in recovering atmospheric water vapour on a scale large enough to supply water to the city of Theodosia (presently Feodosia, Crimea, Ukraine). Several attempts were made in the early 20th Cent. to build artificial dew-catching constructions which were subsequently abandoned because of their low yield....

  4. Purified water quality study

    Energy Technology Data Exchange (ETDEWEB)

    Spinka, H.; Jackowski, P.

    2000-04-03

    Argonne National Laboratory (HEP) is examining the use of purified water for the detection medium in cosmic ray sensors. These sensors are to be deployed in a remote location in Argentina. The purpose of this study is to provide information and preliminary analysis of available water treatment options and associated costs. This information, along with the technical requirements of the sensors, will allow the project team to determine the required water quality to meet the overall project goals.

  5. Light water reactor safety

    CERN Document Server

    Pershagen, B

    2013-01-01

    This book describes the principles and practices of reactor safety as applied to the design, regulation and operation of light water reactors, combining a historical approach with an up-to-date account of the safety, technology and operating experience of both pressurized water reactors and boiling water reactors. The introductory chapters set out the basic facts upon which the safety of light water reactors depend. The central section is devoted to the methods and results of safety analysis. The accidents at Three Mile Island and Chernobyl are reviewed and their implications for light wate

  6. [Water hygiene in hospitals].

    Science.gov (United States)

    Kerwat, Klaus; Wulf, Hinnerk

    2013-10-01

    As a general rule drinking water in hospitals does not represent a risk for the normal patient. However, for high-risk patients with compromised immune defense systems drinking water in hospitals may become a source of nosocomial infections. It may be contaminated with microorganisms that may have the potential to be infectious agents in the hospital environment. Of particular significance in such circumstances are the Gram-negative rods such as Pseudomonas aeruginosa, Acinetobacter spp. and Legionella bacteria. Accordingly, specific behavior patterns and measures in the handling of drinking water in hospitals are meaningful in order to reduce the risks of water-associated nosocomial infections.

  7. Water and Tie

    Institute of Scientific and Technical Information of China (English)

    小诗

    1999-01-01

    A tourist got separated from his tour group in the Sahara. He begged apassing nomad (游牧部落的人) for water." Sorry," said the tribesman (部落男子), "I have no water, but I do have some lovely neckties I’ll sell you." "Youmust be crazy," the tourist mumbled (喃喃而语). Nearly dead from thirst, hespied (发现) another man." Water!" the tourist gasped. "Please, give mewater. ""I have no water," came the reply, "only these handsome ties, which Iwill happily sell you."

  8. Water quality monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Conio, O. [Azienda Mediterranea Gas e Acqua spa, Genua (Italy)

    1998-12-31

    By involving institutions and rules, and technology as well, water resources management presents remarkable complexity. In institutions such a complexity is due to division of competence into monitoring activities, quality control, water utility supply and water treatment. As far as technology goes, complexity results from a wide range of physical, chemical and biological requisites, which define water quality according to specific water uses (for populations, farms, factories). Thus it`s necessary to have reliable and in-time environmental data, so to fulfil two complementary functions: 1) the control of any state of emergency, such as floods and accidental pollution, in order to take immediate measures by means of timely available information; 2) the mid- and long-term planning of water resources, so to achieve their reclamation, conservation and exploitation. An efficient and reliable way to attain these goals is to develop integrated continuous monitoring systems, which allow to control the quality of surface and underground water, the flow of bodies of water and those weather conditions that directly affect it. Such systems compose an environmental information network, which enables to collect and process data relative to the state of the body of water, its aquifer, and the weather conditions.

  9. Air/Water Purification

    Science.gov (United States)

    1992-01-01

    After 18 years of research into air/water pollution at Stennis Space Center, Dr. B. C. Wolverton formed his own company, Wolverton Environmental Services, Inc., to provide technology and consultation in air and water treatment. Common houseplants are used to absorb potentially harmful materials from bathrooms and kitchens. The plants are fertilized, air is purified, and wastewater is converted to clean water. More than 100 U.S. communities have adopted Wolverton's earlier water hyacinth and artificial marsh applications. Catfish farmers are currently evaluating the artificial marsh technology as a purification system.

  10. Viruses in renovated waters

    CSIR Research Space (South Africa)

    Nupen, EM

    1974-06-01

    Full Text Available . SPRODI, O.J. (1973) Quality of recycled water. Fate of infectious agents. Jour. Inst. Can. Sd. Technol. Aliment 6 (2), 91. 6. SPROUL, O.J., LAROCHELLE, L.R., WENTWORTH, B.?. and PHORUP, R.T. (1967) Virus removal in water re?use treating processes... to assess the present and future needs f?r such water~ and the virus risk involved in their usage. The available knowledge of the efficiency of natural purification processes in virus removal, by water purification techniques treating possibly polluted...

  11. Jumping on water

    Science.gov (United States)

    Kim, Ho-Young

    2016-11-01

    Water striders can jump on water as high as they can jump on land. Quick jumps allow them to avoid sudden dangers such as predators' attacks, and therefore understanding how they make such a dramatic motion for survival can shed light on the ultimate level of semi-aquatic motility achievable through evolution. However, the mechanism of their vertical jumping from a water surface has eluded hydrodynamic explanations so far. By observing movements of water strider legs and theoretically analyzing their dynamic interactions with deforming liquid-air interface, we have recently found that different species of jumping striders always tune their leg rotation speed with a force just below that required to break the water surface to reach the maximum take-off velocity. Here, we start with discussing the fundamental theories of dynamics of floating and sinking of small objects. The theories then enable us to analyze forces acting on a water strider while it presses down the water surface to fully exploit the capillary force. We further introduce a 68-milligram at-scale robotic insect capable of jumping on water without splash, strikingly similar to the real strider, by utilizing the water surface just as a trampoline.

  12. Production of heavy water

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, Larry S.; Brown, Sam W.; Phillips, Michael R.

    2017-06-06

    Disclosed are methods and apparatuses for producing heavy water. In one embodiment, a catalyst is treated with high purity air or a mixture of gaseous nitrogen and oxygen with gaseous deuterium all together flowing over the catalyst to produce the heavy water. In an alternate embodiment, the deuterium is combusted to form the heavy water. In an alternate embodiment, gaseous deuterium and gaseous oxygen is flowed into a fuel cell to produce the heavy water. In various embodiments, the deuterium may be produced by a thermal decomposition and distillation process that involves heating solid lithium deuteride to form liquid lithium deuteride and then extracting the gaseous deuterium from the liquid lithium deuteride.

  13. Ghana - Water and Sanitation

    Data.gov (United States)

    Millennium Challenge Corporation — The Ghana Community Services Activity was designed to complement the Agriculture Project by providing educational, water and sanitation and rural electrification...

  14. Water: A looming crisis?

    CSIR Research Space (South Africa)

    Cloete, D

    2010-04-01

    Full Text Available water footprint extends to its supply chain. Coca-Cola thought it was using 2.5 litres of water to produce a litre of coke, but when it looked at its supply chain it realised the actual ¦gure was 200 litres. †is prompted it to link up with the WWF... also need to start thinking about food production in neighbouring countries with higher rainfall. Hope- fully we will learn to use water far more e‡ciently, and to appreciate our ground water. Martin Ginster Environmental advisor, Sasol SOUTH...

  15. Water - an inexhaustible resource?

    Science.gov (United States)

    Le Divenah, C.; Esperou, E.

    2012-04-01

    We have chosen to present the topic "Water", by illustrating problems that will give better opportunities for interdisciplinary work between Natural Science (Physics, Chemistry, Biology and Geology) teachers at first, but also English teachers and maybe others. Water is considered in general, in all its shapes and states. The question is not only about drinking water, but we would like to demonstrate that water can both be a fragile and short-lived resource in some ways, and an unlimited energy resource in others. Water exists on Earth in three states. It participates in a large number of chemical and physical processes (dissolution, dilution, biogeochemical cycles, repartition of heat in the oceans and the atmosphere, etc.), helping to maintain the homeostasis of the entire planet. It is linked to living beings, for which water is the major compound. The living beings essentially organized themselves into or around water, and this fact is also valid for human kind (energy, drinking, trade…). Water can also be a destroying agent for living beings (tsunamis, mud flows, collapse of electrical dams, pollution...) and for the solid earth (erosion, dissolution, fusion). I) Water, an essential resource for the human kind After having highlighted the disparities and geopolitical problems, the pupils will study the chemistry of water with its components and their origins (isotopes, water trip). Then the ways to make it drinkable will be presented (filtration, decantation, iceberg carrying…) II) From the origin of water... We could manage an activity where different groups put several hypotheses to the test, with the goal to understand the origin(s?) of water on Earth. Example: Isotopic signature of water showing its extraterrestrial origin.. Once done, we'll try to determine the origin of drinking water, as a fossil resource. Another use of isotopes will allow them to evaluate the drinking water age, to realize how precious it can be. III) Water as a sustainable energy

  16. Saving water through global trade

    NARCIS (Netherlands)

    Chapagain, A.K.; Hoekstra, A.Y.; Savenije, H.H.G.

    2005-01-01

    Many nations save domestic water resources by importing water-intensive products and exporting commodities that are less water intensive. National water saving through the import of a product can imply saving water at a global level if the flow is from sites with high to sites with low water product

  17. Saving water through global trade

    NARCIS (Netherlands)

    Chapagain, Ashok; Hoekstra, Arjen Ysbert; Savenije, H.H.G.

    2005-01-01

    Many nations save domestic water resources by importing water-intensive products and exporting commodities that are less water intensive. National water saving through the import of a product can imply saving water at a global level if the flow is from sites with high to sites with low water

  18. Water footprint as a tool for integrated water resources management

    Science.gov (United States)

    Aldaya, Maite; Hoekstra, Arjen

    2010-05-01

    In a context where water resources are unevenly distributed and, in some regions precipitation and drought conditions are increasing, enhanced water management is a major challenge to final consumers, businesses, water resource users, water managers and policymakers in general. By linking a large range of sectors and issues, virtual water trade and water footprint analyses provide an appropriate framework to find potential solutions and contribute to a better management of water resources. The water footprint is an indicator of freshwater use that looks not only at direct water use of a consumer or producer, but also at the indirect water use. The water footprint of a product is the volume of freshwater used to produce the product, measured over the full supply chain. It is a multi-dimensional indicator, showing water consumption volumes by source and polluted volumes by type of pollution; all components of a total water footprint are specified geographically and temporally. The water footprint breaks down into three components: the blue (volume of freshwater evaporated from surface or groundwater systems), green (water volume evaporated from rainwater stored in the soil as soil moisture) and grey water footprint (the volume of polluted water associated with the production of goods and services). Closely linked to the concept of water footprint is that of virtual water trade, which represents the amount of water embedded in traded products. Many nations save domestic water resources by importing water-intensive products and exporting commodities that are less water intensive. National water saving through the import of a product can imply saving water at a global level if the flow is from sites with high to sites with low water productivity. Virtual water trade between nations and even continents could thus be used as an instrument to improve global water use efficiency and to achieve water security in water-poor regions of the world. The virtual water trade

  19. WaterWatch -- Current Water Resources Conditions

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — WaterWatch (http://waterwatch.usgs.gov) is a U.S. Geological Survey (USGS) World Wide Web site that displays maps, graphs, and tables describing real-time, recent,...

  20. Water footprints and sustainable water allocation

    NARCIS (Netherlands)

    Hoekstra, Arjen Ysbert; Chapagain, Ashok; Zhang, Guoping

    2016-01-01

    Water Footprint Assessment (WFA) is a quickly growing research field. This Special Issue contains a selection of papers advancing the field or showing innovative applications. The first seven papers are geographic WFA studies, from an urban to a continental scale; the next five papers have a global

  1. Recent Water Issues in China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The rapid urbanization process in China over the past thirty years has significantly improved the living standards of Chinese people. But it also poses severe environmental pressure on environment including water. This paper discusses the water issues like urban water supply, water pollution and water quality of water system in the context of the rapid urbanization process in China. It then proposes strategic measures to tackle those water issues and discusses the progress of providing safe drinking water and protecting water resources by new technologies in-cluding membrane technology. It concludes that water is a global issue and should be tackled by global community together.

  2. Values of water

    NARCIS (Netherlands)

    Doorn, N.; Dicke, W.M.

    2012-01-01

    Water is essential for human life. However, due to its scarcity, the management of water is a topic of great concern. Inadequate management may lead to famines, food insecurity, ecological destruction, and resource-based conflicts, and eventually to human suffering and the loss of millions of human

  3. The Dirty Water Challenge

    Science.gov (United States)

    Walker, Mark; Kremer, Angelika; Schluter, Kirsten

    2007-01-01

    "The Dirty Water Challenge" is a fun activity that teaches children about their environment in an engaging and practical way. Inquiry is embedded within the practical--students have to design, plan, and then build their own design of water filter. Students are exposed to important concepts from a variety of scientific disciplines, including how…

  4. Asia's water balance

    NARCIS (Netherlands)

    Immerzeel, W.W.; Bierkens, M.F.P.

    The availability of water for human consumption and agriculture can no longer be taken for granted. Various facets of water stress at different spatial scales, such as groundwater depletion1,2, climate change and population increase3, and glacier and snow melt4,5, have been recognized as

  5. Auto's te water.

    NARCIS (Netherlands)

    Vis, A.A.

    1970-01-01

    Yearly in the Netherlands, about 1200 vehicles fall into the water, out of which 80 to 100 occupants are killed. Investigations done on this subject showed that a) a vehicle fallen into the water can already be vacated in several ways during the drifting b) the construction and equipment of the vehi

  6. Values of water

    NARCIS (Netherlands)

    Doorn, N.; Dicke, W.M.

    2012-01-01

    Water is essential for human life. However, due to its scarcity, the management of water is a topic of great concern. Inadequate management may lead to famines, food insecurity, ecological destruction, and resource-based conflicts, and eventually to human suffering and the loss of millions of human

  7. Electrofreezing of confined water

    NARCIS (Netherlands)

    Zangi, R; Mark, AE

    2004-01-01

    We report results from molecular dynamics simulations of the freezing transition of TIP5P water molecules confined between two parallel plates under the influence of a homogeneous external electric field, with magnitude of 5 V/nm, along the lateral direction. For water confined to a thickness of a

  8. Economics of Water Management

    NARCIS (Netherlands)

    Zhu, X.

    2015-01-01

    Water is a scarce natural resource. It is not only used as an input to economic activity such as irrigation, household and industrial water use, and hydropower generation, but also provides ecosystem services such as the maintenance of wetlands, wildlife support, and river flows for aquatic

  9. Water on Stream Again

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Sichuan Province has repaired quake-damaged hydro infrastructure and aspires to further expand its irrigation facilities As crops grow taller in warm April farmers are busy with watering them. The sound of gurgling water is heard along the road to the Guansong Pengyan

  10. Water Reclamation and Reuse.

    Science.gov (United States)

    Smith, Daniel W.

    1978-01-01

    Presents a literature review of water reclamation and reuse. This review covers: (1) water resources planning; (2) agriculture and irrigation; (3) ground recharge; (4) industrial reuse; (5) health considerations; and (6) technology developments. A list of 217 references is also presented. (HM)

  11. Shallow water tides

    Digital Repository Service at National Institute of Oceanography (India)

    Unnikrishnan, A.S.

    stream_size 3 stream_content_type text/plain stream_name Trg_Calculat_Water_Depth_Chart_Datum_1991_22.pdf.txt stream_source_info Trg_Calculat_Water_Depth_Chart_Datum_1991_22.pdf.txt Content-Encoding ISO-8859-1 Content-Type text...

  12. Water Quality Monitoring Manual.

    Science.gov (United States)

    Mason, Fred J.; Houdart, Joseph F.

    This manual is designed for students involved in environmental education programs dealing with water pollution problems. By establishing a network of Environmental Monitoring Stations within the educational system, four steps toward the prevention, control, and abatement of water pollution are proposed. (1) Train students to recognize, monitor,…

  13. Water-filled telescopes

    CERN Document Server

    Antonello, E

    2014-01-01

    In this short note we discuss the case of the thought experiments on water-filled telescopes and their realizations during 18th and 19th century. The story of those instruments shows that the scientific progress occurs in a curious way, since there was no stringent reason for the construction of a water-filled telescope.

  14. EPANET water quality model

    Energy Technology Data Exchange (ETDEWEB)

    Rossman, L.A.

    1993-01-01

    EPANET represents a third generation of water quality modeling software developed by the U.S. EPA's Drinking Water Research Division, offering significant advances in the state of the art for network water quality analysis. EPANET performs extended period simulation of hydraulic and water quality behavior within water distribution systems. In addition to substance concentration, water age and source tracing can also be simulated. EPANET includes a full featured hydraulic simulation model that can handle various types of pumps, valves, and their control rules. The water quality module is equipped to handle constituent reactions within the bulk pipe flow and at the pipe wall. It also features an efficient computational scheme that automatically determines optimal time steps and pipe segmentation for accurate tracking of material transport over time. EPANET is currently being used in the US to study such issues as loss of chlorine residual, source blending and trihalomethane (THM) formation, how altered tank operation affects water age, and total dissolved solids (TDS) control for an irrigation network.

  15. Water Treatment Technology - Filtration.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on filtration provides instructional materials for six competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: purposes of sedimentation basins and flocculation…

  16. Water Chemistry Laboratory Manual.

    Science.gov (United States)

    Jenkins, David; And Others

    This manual of laboratory experiments in water chemistry serves a dual function of illustrating fundamental chemical principles of dilute aqueous systems and of providing the student with some familiarity with the chemical measurements commonly used in water and wastewater analysis. Experiments are grouped in categories on the basis of similar…

  17. Supramolecular Chemistry in Water

    NARCIS (Netherlands)

    Oshovsky, Gennady V.; Reinhoudt, David N.; Verboom, Willem

    2007-01-01

    Supramolecular chemistry in water is a constantly growing research area because noncovalent interactions in aqueous media are important for obtaining a better understanding and control of the major processes in nature. This Review offers an overview of recent advances in the area of water-soluble sy

  18. Water Pollution, Teachers' Edition.

    Science.gov (United States)

    Lavaroni, Charles W.; And Others

    One of three in a series about pollution, this teacher's guide for a unit on water pollution is designed for use in junior high school grades. It offers suggestions for extending the information and activities contained in the textual material for students. Chapter 1 discusses the problem of water pollution and involves students in processes of…

  19. The Other Water Pollution

    Science.gov (United States)

    Barton, Kathy

    1978-01-01

    Nonpoint source pollution, water pollution not released at one specific identifiable point, now accounts for 50 percent of the nation's water pollution problem. Runoff is the primary culprit and includes the following sources: agriculture, mining, hydrologic modifications, and urban runoff. Economics, legislation, practices, and management of this…

  20. Managing water for life

    Institute of Scientific and Technical Information of China (English)

    Daniel P. LOUCKS; Haifeng JIA

    2012-01-01

    Water is essential for life. In spite of the entire engineering infrastructure devoted to the treatment, regulation and beneficial uses of water, occasionally sufficient quantities and qualities of water become scarce. When this happens, just how do we decide how much less water to allocate to all of us and the activities we engage in to sustain and enhance our quality of life? This paper addresses some of the complexities of answering such a question, especially as society increasingly recognizes the need to provide flow regimes that will maintain healthy aquatic and floodplain ecosystems that also impact the economic, physical and even the spiritual quality of our lives. For we depend on these ecosystems to sustain our wellbeing. We are indeed a part of our ecosystems. We depend upon on aquatic ecosystems to moderate river flow qualities and quantities, reduce the extremes of floods and droughts, reduce erosion, detoxify and decompose water- borne wastes, generate and preserve flood plain soils and renew their fertility, regulate disease carrying organisms, and to enhance recreational benefits of river systems. This question of deciding just how much water to allocate to each water user and for the maintenance of viable aquatic ecosystems, especially when there is not enough, is a complex, and largely political, issue. This issue is likely to become even more complex and political and contentious in the future as populations grow and as water quantities and their qualities become even more variable and uncertain.

  1. Deficiencies in Water Conservancy

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Recent droughts and floods show the fragility of China’s water conservancy capabilities Be it extreme flooding or severe droughts,China has yet to find a stable middle ground concerning its water supply.These disasters,primarily in the Yangtze

  2. Water injection dredging

    NARCIS (Netherlands)

    Verhagen, H.J.

    2000-01-01

    Some twenty years ago WIS-dredging has been developed in the Netherlands. By injecting water into the mud layer, the water content of the mud becomes higher, it becomes fluid mud and will start to flow. The advantages of this system are that there is no need of transporting the mud in a hopper, and

  3. Drinking Water and Health.

    Science.gov (United States)

    National Academy of Sciences, Washington, DC.

    In response to a provision of the Safe Drinking Water Act of 1974 which called for a study that would serve as a scientific basis for revising the primary drinking water regulations that were promulgated under the Act, a study of the scientific literature was undertaken in order to assess the implications for human health of the constituents of…

  4. Water Pollution, Teachers' Edition.

    Science.gov (United States)

    Lavaroni, Charles W.; And Others

    One of three in a series about pollution, this teacher's guide for a unit on water pollution is designed for use in junior high school grades. It offers suggestions for extending the information and activities contained in the textual material for students. Chapter 1 discusses the problem of water pollution and involves students in processes of…

  5. The Other Water Pollution

    Science.gov (United States)

    Barton, Kathy

    1978-01-01

    Nonpoint source pollution, water pollution not released at one specific identifiable point, now accounts for 50 percent of the nation's water pollution problem. Runoff is the primary culprit and includes the following sources: agriculture, mining, hydrologic modifications, and urban runoff. Economics, legislation, practices, and management of this…

  6. Purge water management system

    Science.gov (United States)

    Cardoso-Neto, Joao E.; Williams, Daniel W.

    1996-01-01

    A purge water management system for effectively eliminating the production of purge water when obtaining a groundwater sample from a monitoring well. In its preferred embodiment, the purge water management system comprises an expandable container, a transportation system, and a return system. The purge water management system is connected to a wellhead sampling configuration, typically permanently installed at the well site. A pump, positioned with the monitoring well, pumps groundwater through the transportation system into the expandable container, which expands in direct proportion with volume of groundwater introduced, usually three or four well volumes, yet prevents the groundwater from coming into contact with the oxygen in the air. After this quantity of groundwater has been removed from the well, a sample is taken from a sampling port, after which the groundwater in the expandable container can be returned to the monitoring well through the return system. The purge water management system prevents the purge water from coming in contact with the outside environment, especially oxygen, which might cause the constituents of the groundwater to oxidize. Therefore, by introducing the purge water back into the monitoring well, the necessity of dealing with the purge water as a hazardous waste under the Resource Conservation and Recovery Act is eliminated.

  7. Trees, forests and water

    NARCIS (Netherlands)

    Ellison, David; Morris, Cindy E.; Locatelli, Bruno; Sheil, Douglas; Cohen, Jane; Murdiyarso, Daniel; Gutierrez, Victoria; Noordwijk, van Meine; Creed, Irena F.; Pokorny, Jan; Gaveau, David; Spracklen, Dominick V.; Tobella, Aida Bargués; Ilstedt, Ulrik; Teuling, Adriaan J.; Gebrehiwot, Solomon Gebreyohannis; Sands, David C.; Muys, Bart; Verbist, Bruno; Springgay, Elaine; Sugandi, Yulia; Sullivan, Caroline A.

    2017-01-01

    Forest-driven water and energy cycles are poorly integrated into regional, national, continental and global decision-making on climate change adaptation, mitigation, land use and water management. This constrains humanity's ability to protect our planet's climate and life-sustaining functions. The

  8. Water footprints and 'pozas'

    NARCIS (Netherlands)

    Domínguez Guzmán, Carolina; Verzijl, Andres; Zwarteveen, Margreet

    2017-01-01

    In this article we present two logics of water efficiency: that of the Water Footprint and that of mango smallholder farmers on the desert coast of Peru (in Motupe). We do so in order to explore how both can learn from each other and to discuss what happens when the two logics meet. Rather than

  9. Pesticides in Ground Water

    DEFF Research Database (Denmark)

    Bjerg, Poul Løgstrup

    1996-01-01

    Review af: Jack E. Barbash & Elizabeth A. Resek (1996). Pesticides in Ground Water. Distribution trends and governing factors. Ann Arbor Press, Inc. Chelsea, Michigan. pp 588.......Review af: Jack E. Barbash & Elizabeth A. Resek (1996). Pesticides in Ground Water. Distribution trends and governing factors. Ann Arbor Press, Inc. Chelsea, Michigan. pp 588....

  10. Water changed the cities

    DEFF Research Database (Denmark)

    Elle, Morten; Jensen, Marina Bergen

    An improvement in water infrastructure and cleaning up the waters changed many harbour cities in Denmark at the beginning of the 90s. The harbour cities changed from drity, run-down industrial harbours to clean and attractive harbour dwelling creating new city centres and vital city areas...

  11. Water at Interfaces

    DEFF Research Database (Denmark)

    Björneholm, Olle; Hansen, Martin Hangaard; Hodgson, Andrew

    2016-01-01

    The interfaces of neat water and aqueous solutions play a prominent role in many technological processes and in the environment. Examples of aqueous interfaces are ultrathin water films that cover most hydrophilic surfaces under ambient relative humidities, the liquid/solid interface which drives...

  12. Water changed the cities

    DEFF Research Database (Denmark)

    Elle, Morten; Jensen, Marina Bergen

    An improvement in water infrastructure and cleaning up the waters changed many harbour cities in Denmark at the beginning of the 90s. The harbour cities changed from drity, run-down industrial harbours to clean and attractive harbour dwelling creating new city centres and vital city areas...

  13. Pesticides in Ground Water

    DEFF Research Database (Denmark)

    Bjerg, Poul Løgstrup

    1996-01-01

    Review af: Jack E. Barbash & Elizabeth A. Resek (1996). Pesticides in Ground Water. Distribution trends and governing factors. Ann Arbor Press, Inc. Chelsea, Michigan. pp 588.......Review af: Jack E. Barbash & Elizabeth A. Resek (1996). Pesticides in Ground Water. Distribution trends and governing factors. Ann Arbor Press, Inc. Chelsea, Michigan. pp 588....

  14. Water Treatment Technology - Springs.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on springs provides instructional materials for two competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on spring basin construction and spring protection. For each competency, student…

  15. Water Treatment Technology - Wells.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on wells provides instructional materials for five competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: dug, driven, and chilled wells, aquifer types, deep well…

  16. Water Treatment Technology - Flouridation.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on flouridation provides instructional materials for three competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: purpose and process of flouridation, correct…

  17. Water Treatment Technology - Pumps.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on pumps provides instructional materials for three competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: types of pumps in plant and distribution systems, pump…

  18. Water Treatment Technology - Hydraulics.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on hydraulics provides instructional materials for three competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: head loss in pipes in series, function loss in…

  19. Water Treatment Technology - Chlorination.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on chlorination provides instructional materials for nine competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: purpose and process of chlorination, chlorine…

  20. Water for energy

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-09-15

    Human civilization has always rested on access to water, and, more specifically, on its utilization. This study aims to contribute to a better understanding of the critical linkages between water and energy and the impact on both of climate change. It identifies areas of opportunity where investment and new regulations are needed, to ensure sustainable global development.