Sample records for hanging drop technique

  1. Etiology and use of the "hanging drop" technique: a review.

    Todorov, Ludmil; VadeBoncouer, Timothy


    Background. The hanging drop (HD) technique presumably relies on the presence of subatmospheric epidural pressure. It is not clear whether this negative pressure is intrinsic or an artifact and how it is affected by body position. There are few data to indicate how often HD is currently being used. Methods. We identified studies that measured subatmospheric pressures and looked at the effect of the sitting position. We also looked at the technique used for cervical and thoracic epidural anesthesia in the last 10 years. Results. Intrinsic subatmospheric pressures were measured in the thoracic and cervical spine. Three trials studied the effect of body position, indicating a higher incidence of subatmospheric pressures when sitting. The results show lower epidural pressure (-10.7 mmHg) with the sitting position. 28.8% of trials of cervical and thoracic epidural anesthesia that documented the technique used, utilized the HD technique. When adjusting for possible bias, the rate of HD use can be as low as 11.7%. Conclusions. Intrinsic negative pressure might be present in the cervical and thoracic epidural space. This effect is more pronounced when sitting. This position might be preferable when using HD. Future studies are needed to compare it with the loss of resistance technique.

  2. Digital microfluidics for automated hanging drop cell spheroid culture.

    Aijian, Andrew P; Garrell, Robin L


    Cell spheroids are multicellular aggregates, grown in vitro, that mimic the three-dimensional morphology of physiological tissues. Although there are numerous benefits to using spheroids in cell-based assays, the adoption of spheroids in routine biomedical research has been limited, in part, by the tedious workflow associated with spheroid formation and analysis. Here we describe a digital microfluidic platform that has been developed to automate liquid-handling protocols for the formation, maintenance, and analysis of multicellular spheroids in hanging drop culture. We show that droplets of liquid can be added to and extracted from through-holes, or "wells," and fabricated in the bottom plate of a digital microfluidic device, enabling the formation and assaying of hanging drops. Using this digital microfluidic platform, spheroids of mouse mesenchymal stem cells were formed and maintained in situ for 72 h, exhibiting good viability (>90%) and size uniformity (% coefficient of variation screen was performed on human colorectal adenocarcinoma spheroids to demonstrate the ability to recapitulate physiologically relevant phenomena such as insulin-induced drug resistance. With automatable and flexible liquid handling, and a wide range of in situ sample preparation and analysis capabilities, the digital microfluidic platform provides a viable tool for automating cell spheroid culture and analysis.

  3. A PDMS-Based Microfluidic Hanging Drop Chip for Embryoid Body Formation.

    Wu, Huei-Wen; Hsiao, Yi-Hsing; Chen, Chih-Chen; Yet, Shaw-Fang; Hsu, Chia-Hsien


    The conventional hanging drop technique is the most widely used method for embryoid body (EB) formation. However, this method is labor intensive and limited by the difficulty in exchanging the medium. Here, we report a microfluidic chip-based approach for high-throughput formation of EBs. The device consists of microfluidic channels with 6 × 12 opening wells in PDMS supported by a glass substrate. The PDMS channels were fabricated by replicating polydimethyl-siloxane (PDMS) from SU-8 mold. The droplet formation in the chip was tested with different hydrostatic pressures to obtain optimal operation pressures for the wells with 1000 μm diameter openings. The droplets formed at the opening wells were used to culture mouse embryonic stem cells which could subsequently developed into EBs in the hanging droplets. This device also allows for medium exchange of the hanging droplets making it possible to perform immunochemistry staining and characterize EBs on chip.

  4. A PDMS-Based Microfluidic Hanging Drop Chip for Embryoid Body Formation

    Huei-Wen Wu


    Full Text Available The conventional hanging drop technique is the most widely used method for embryoid body (EB formation. However, this method is labor intensive and limited by the difficulty in exchanging the medium. Here, we report a microfluidic chip-based approach for high-throughput formation of EBs. The device consists of microfluidic channels with 6 × 12 opening wells in PDMS supported by a glass substrate. The PDMS channels were fabricated by replicating polydimethyl-siloxane (PDMS from SU-8 mold. The droplet formation in the chip was tested with different hydrostatic pressures to obtain optimal operation pressures for the wells with 1000 μm diameter openings. The droplets formed at the opening wells were used to culture mouse embryonic stem cells which could subsequently developed into EBs in the hanging droplets. This device also allows for medium exchange of the hanging droplets making it possible to perform immunochemistry staining and characterize EBs on chip.

  5. Enhancement of nucleation during hanging drop protein crystallization using HF treatment of cover glasses

    Guo, Yun-Zhu; Yin, Da-Chuan; Lu, Qin-Qin; Wang, Xi-Kai; Liu, Jun [Key Laboratory for Space Bioscience and Biotechnology, Faculty of Life Sciences, Northwestern Polytechnical University, Xi' an 710072, Shaanxi (China)


    We examined a simple approach, i.e., etching cover glasses using hydrofluoric acid (HF), to determine whether cover glass treatment enhances nucleation in hanging drop protein crystallization. Hen egg white lysozyme and proteinase K were used as the model proteins. We found that the treatment increased the success rate of crystallization. The results indicated that the simple treatment, which is easy to adopt without changing much in the hanging drop method, can be utilized as an alternative method to enhance protein crystallization screens (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Energy stability of droplets and dry spots in a thin film model of hanging drops

    Cheung, Ka-Luen; Chou, Kai-Seng


    The 2-D thin film equation describing the evolution of hang drops is studied. All radially symmetric steady states are classified, and their energy stability is determined. It is shown that the droplet with zero contact angle is the only global energy minimizer and the dry spot with zero contact angle is a strict local energy minimizer.

  7. Increased sensitivity of anodic stripping voltammetry at the hanging mercury drop electrode by ultracathodic deposition.

    Rodrigues, José A; Rodrigues, Carlos M; Almeida, Paulo J; Valente, Inês M; Gonçalves, Luís M; Compton, Richard G; Barros, Aquiles A


    An improved approach to the anodic stripping voltammetric (ASV) determination of heavy metals, using the hanging mercury drop electrode (HMDE), is reported. It was discovered that using very cathodic accumulation potentials, at which the solvent reduction occurs (overpotential deposition), the voltammetric signals of zinc(II), cadmium(II), lead(II) and copper(II) increase. When compared with the classical methodology a 5 to 10-fold signal increase is obtained. This effect is likely due to both mercury drop oscillation at such cathodic potentials and added local convection at the mercury drop surface caused by the evolution of hydrogen bubbles. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Headspace Hanging Drop Liquid Phase Microextraction and Gas Chromatography-Mass Spectrometry for the Analysis of Flavors from Clove Buds

    Jung, Mi Jin; Shin, Yeon Jae; Oh, Se Yeon; Kim, Nam Sun; Kim, Kun; Lee, Dong Sun [Seoul Women' s University, Seoul (Korea, Republic of)


    A novel sample pretreatment technique, headspace hanging drop liquid phase microextraction (HS-LPME) was studied and applied to the determination of flavors from solid clove buds by gas chromatography-mass spectrometry (GC-MS). Several parameters affecting on HS-LPME such as organic solvent drop volume, extraction time, extraction temperature and phase ratio were investigated. 1-Octanol was selected as the extracting solvent, drop size was fixed to 0.6 μL. 60 min extraction time at 25 .deg. C was chosen. HS-LPME has the good efficiency demonstrated by the higher partition equilibrium constant (K{sub lh}) values and concentration factor (CF) values. The limits of detection (LOD) were 1.5-3.2 ng. The amounts of eugenol, β-caryophyllene and eugenol acetate from the clove bud sample were 1.90 mg/g, 1.47 mg/g and 7.0 mg/g, respectively. This hanging drop based method is a simple, fast and easy sample enrichment technique using minimal solvent. HSLPME is an alternative sample preparation method for the analysis of volatile aroma compounds by GC-MS.

  9. The influence of gravity on the distribution of the deposit formed onto a substrate by sessile, hanging, and sandwiched hanging drop evaporation.

    Sandu, Ion; Fleaca, Claudiu Teodor


    The focus of the present article is the study of the influence of gravity on the particle deposition profiles on a solid substrate during the evaporation of sessile, hanging and sandwiched hanging drops of colloidal particle suspensions. For concentrations of nanoparticles in the colloidal solutions in the range 0.0001-1 wt.%, highly diluted suspensions will preferentially form rings while concentrated suspensions will preferentially form spots in both sessile and hanging drop evaporation. For intermediary concentrations, the particle deposition profiles will depend on the nanoparticle aggregation dynamics in the suspension during the evaporation process, gravity and on the detailed evaporation geometry. The evaporation of a drop of toluene/carbon nanoparticle suspension hanging from a pendant water drop will leave on the substrate a circular spot with no visible external ring. By contrast, a clear external ring is formed on the substrate by the sessile evaporation of a similar drop of suspension sandwiched between a water drop and the substrate. From the application viewpoint, these processes can be used to create preferential electrical conductive carbon networks and contacts for arrays of self-assembled nanostructures fabricated on solid substrates as well as on flexible polymeric substrates.

  10. Use of layer silicate for protein crystallization: effects of Micromica and chlorite powders in hanging drops.

    Takehara, Masahide; Ino, Keita; Takakusagi, Yoichi; Oshikane, Hiroyuki; Nureki, Osamu; Ebina, Takeo; Mizukami, Fujio; Sakaguchi, Kengo


    Two kinds of layer silicate powder, Micromica and chlorite, were used to aid protein crystallization by the addition to hanging drops. Using appropriate crystallization buffers, Micromica powder facilitated crystal growth speed for most proteins tested in this study. Furthermore, the addition of Micromica powder to hanging drops allowed the successful crystallization of lysozyme, catalase, concanavalin A, and trypsin even at low protein concentrations and under buffer conditions that otherwise would not generate protein crystals. Except for threonine synthase and apoferritin, the presence of chlorite delayed crystallization but induced the formation of large crystals. X-ray analysis of thaumatin crystals generated by our novel procedure gave better quality data than did that of crystals obtained by a conventional hanging drop method. Our results suggest that the speed of crystal growth and the quality of the corresponding X-ray data may be inversely related, at least for the formation of thaumatin crystals. The effect of Micromica and chlorite powders and the application of layer silicate powder for protein crystallization are discussed.

  11. Mathematical Modelling of the Electrode Process of Azithromycin Using Cyclic Voltammetry at Hanging Mercury Drop Electrode

    Maha F. Tutunji


    Full Text Available A theoretical treatment is presented to predict the kinetic behaviour of azithromycin at the surface of hanging mercury drop electrode using cyclic voltammetry. A model is developed to incorporate the occurrence of adsorption of the oxidized and reduced species of azithromycin at the surface of mercury drop electrode. An analytical solution was obtained using MATHEMATICA (V-3, Wolfram Research, Inc. to predict the cyclic voltammetric profiles by calculating the currents resulting after applying variable potentials ranging –1.9 to –1.3 V versus Ag/AgCl. Simulation runs at different initial concentrations of azithromycin and different scan rates showed good agreement with experimental findings. However, this model should be modified to describe a multilayer adsorption with irreversible electrochemical reaction.

  12. Increased sensitivity of anodic stripping voltammetry at the hanging mercury drop electrode by ultracathodic deposition

    Rodrigues, Jose A.; Rodrigues, Carlos M.; Almeida, Paulo J.; Valente, Ines M.; Goncalves, Luis M. [Requimte - Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, no. 687, 4169-007 Porto (Portugal); Compton, Richard G. [Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ (United Kingdom); Barros, Aquiles A., E-mail: [Requimte - Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, no. 687, 4169-007 Porto (Portugal)


    Highlights: {yields} At very cathodic accumulation potentials (overpotential deposition) the voltammetric signals of Zn{sup 2+}, Cd{sup 2+}, Pb{sup 2+} and Cu{sup 2+} increase. {yields} 5 to 10-fold signal increase is obtained. {yields} This effect is likely due to mercury drop oscillation at such cathodic potentials. {yields} This effect is also likely due to added local convection at the mercury drop surface caused by the evolution of hydrogen bubbles. - Abstract: An improved approach to the anodic stripping voltammetric (ASV) determination of heavy metals, using the hanging mercury drop electrode (HMDE), is reported. It was discovered that using very cathodic accumulation potentials, at which the solvent reduction occurs (overpotential deposition), the voltammetric signals of zinc(II), cadmium(II), lead(II) and copper(II) increase. When compared with the classical methodology a 5 to 10-fold signal increase is obtained. This effect is likely due to both mercury drop oscillation at such cathodic potentials and added local convection at the mercury drop surface caused by the evolution of hydrogen bubbles.

  13. Experimental and theoretical analysis of the rate of solvent equilibration in the hanging drop method of protein crystal growth

    Fowlis, William W.; Delucas, Lawrence J.; Twigg, Pamela J.; Howard, Sandra B.; Meehan, Edward J.


    The principles of the hanging-drop method of crystal growth are discussed, and the rate of water evaporation in a water droplet (containing protein, buffer, and a precipitating agent) suspended above a well containing a double concentration of precipitating agent is investigated theoretically. It is shown that, on earth, the rate of evaporation may be determined from diffusion theory and the colligative properties of solutions. The parameters affecting the rate of evaporation include the temperature, the vapor pressure of water, the ionization constant of the salt, the volume of the drop, the contact angle between the droplet and the coverslip, the number of moles of salt in the droplet, the number of moles of water and salt in the well, the molar volumes of water and salt, the distance from the droplet to the well, and the coefficient of diffusion of water vapor through air. To test the theoretical equations, hanging-drop experiments were conducted using various reagent concentrations in 25-microliter droplets and measuring the evaporation times at 4 C and 25 C. The results showed good agreement with the theory.

  14. Life-History Traits of the Model Organism Pristionchus pacificus Recorded Using the Hanging Drop Method: Comparison with Caenorhabditis elegans.

    Gilarte, Patricia; Kreuzinger-Janik, Bianca; Majdi, Nabil; Traunspurger, Walter


    The nematode Pristionchus pacificus is of growing interest as a model organism in evolutionary biology. However, despite multiple studies of its genetics, developmental cues, and ecology, the basic life-history traits (LHTs) of P. pacificus remain unknown. In this study, we used the hanging drop method to follow P. pacificus at the individual level and thereby quantify its LHTs. This approach allowed direct comparisons with the LHTs of Caenorhabditis elegans recently determined using this method. When provided with 5×10(9) Escherichia coli cells ml(-1) at 20°C, the intrinsic rate of natural increase of P. pacificus was 1.125 (individually, per day); mean net production was 115 juveniles produced during the life-time of each individual, and each nematode laid an average of 270 eggs (both fertile and unfertile). The mean age of P. pacificus individuals at first reproduction was 65 h, and the average life span was 22 days. The life cycle of P. pacificus is therefore slightly longer than that of C. elegans, with a longer average life span and hatching time and the production of fewer progeny.

  15. Life-History Traits of the Model Organism Pristionchus pacificus Recorded Using the Hanging Drop Method: Comparison with Caenorhabditis elegans.

    Patricia Gilarte

    Full Text Available The nematode Pristionchus pacificus is of growing interest as a model organism in evolutionary biology. However, despite multiple studies of its genetics, developmental cues, and ecology, the basic life-history traits (LHTs of P. pacificus remain unknown. In this study, we used the hanging drop method to follow P. pacificus at the individual level and thereby quantify its LHTs. This approach allowed direct comparisons with the LHTs of Caenorhabditis elegans recently determined using this method. When provided with 5×10(9 Escherichia coli cells ml(-1 at 20°C, the intrinsic rate of natural increase of P. pacificus was 1.125 (individually, per day; mean net production was 115 juveniles produced during the life-time of each individual, and each nematode laid an average of 270 eggs (both fertile and unfertile. The mean age of P. pacificus individuals at first reproduction was 65 h, and the average life span was 22 days. The life cycle of P. pacificus is therefore slightly longer than that of C. elegans, with a longer average life span and hatching time and the production of fewer progeny.

  16. Differential pulse cathodic stripping voltammetric determination of uranium with arsenazo-III at the hanging mercury dropping electrode

    Kadi, M.W.; El-Shahawi, M.S. [Chemistry Dept., King Abdulaziz Univ., Jeddah (Saudi Arabia)


    An accurate, inexpensive and less laborious controlled adsorptive accumulation of uranium(VI)-arsenazo-III on a hanging mercury drop electrode (HMDE) has been developed for uranium(VI) determination. The method is based upon the collection of uranium(VI)-arsenazo-III complex at pH 5-6 at the HMDE and subsequent direct stripping measurement of the element in the nanomolar concentration level. The cathodic peak current (i{sub p,c}) of the adsorbed complex ions of uranium(VI) was measured at -0.35 V vs. Ag/AgCl reference electrode by differential pulse cathodic stripping voltammetry (DP-CSV), proceeded by an accumulation period of 150s2.5 in Britton-Robinson buffer of pH 5. The plot of the resulting i{sub p,c} vs. uranium(VI) concentration was linear in the range 2.1 x 10{sup -9} to 9.60 x 10{sup -7} mol L{sup -1} uranium(VI) and tended to level off at above 9.6 x 10{sup -7} mol L{sup -1}. The limits of detection and quantification of uranium(VI) were found to be 4.7 x 10{sup -10} and 1.5 x 10{sup -9} mol L{sup -1}, respectively. A relative standard deviation of {+-}2.39% (n = 5) at 8.5 x 10{sup -7} mol L{sup -1} uranium(VI) was obtained. The method was validated by comparing the results with that obtained by ICP-MS method with RSD less than {+-}3.3%. The method was applied successfully for the analysis of uranium in certified reference material (IAEA soil-7), and in phosphate fertilizers. (orig.)

  17. Hemi-hepatectomy in pediatric patients using two-surgeon technique and a liver hanging maneuver

    Kyoko Mochizuki; Susumu Eguchi; Ryuichiro Hirose; Taiichiro Kosaka; Mitsuhisa Takatsuki; Takashi Kanematsu


    AIM: To evaluate the efficacy of the two-surgeon technique with the liver hanging maneuver (LHM) for hepatectomies in pediatric patients with hepatoblastoma. METHODS: Three pediatric patients with hepatoblastoma were enrolled in this study. Two underwent right hemi-hepatectomies and one underwent a left hemihepatectomy using the two-surgeon technique by means of saline-linked electric cautery (SLC) and the Cavitron Ultrasonic Surgical Aspirator (CUSA; Valleylab, Boulder, CO) and the LHM. RESULTS: The mean operative time during the parenchymal transections was 50 min and the mean blood loss was 235 g. There was no bile leakage from the cut surface after surgery. No macroscopic or microscopic-positive margins were observed in the hepatic transections. CONCLUSION: The two-surgeon technique using SLC and CUSA with the LHM is applicable to even pediatric patients with hepatoblastoma.

  18. Hanging drop cultures of human testis and testis cancer samples: a model used to investigate activin treatment effects in a preserved niche

    Jørgensen, A; Young, J; Nielsen, J E; Joensen, U N; Toft, B G; Rajpert-De Meyts, E; Loveland, K L


    Background: Testicular germ cell tumours of young adults, seminoma or non-seminomas, are preceded by a pre-invasive precursor, carcinoma in situ (CIS), understood to arise through differentiation arrest of embryonic germ cells. Knowledge about the malignant transformation of germ cells is currently limited by the lack of experimental models. The aim of this study was to establish an experimental tissue culture model to maintain normal and malignant germ cells within their niche and allow investigation of treatment effects. Methods: Human testis and testis cancer specimens from orchidectomies were cultured in ‘hanging drops' and effects of activin A and follistatin treatment were investigated in seminoma cultures. Results: Testis fragments with normal spermatogenesis or CIS cells were cultured for 14 days with sustained proliferation of germ cells and CIS cells and without increased apoptosis. Seminoma cultures survived 7 days, with proliferating cells detectable during the first 5 days. Activin A treatment significantly reduced KIT transcript and protein levels in seminoma cultures, thereby demonstrating a specific treatment response. Conclusions: Hanging drop cultures of human testis and testis cancer samples can be employed to delineate mechanisms governing growth of normal, CIS and tumorigenic germ cells retained within their niche. PMID:24781282

  19. Comparative study of P19 EC stem cell differentiation in between conventional hanging drop and the zebrafish chorion as a bio-derived material.

    Dae Seok Na; Lee, Hwang; Sun Uk Kim; Chang Nam Hwang; Sang Ho Lee; Ji Yoon Kang; Jai Kyeong Kim; James Jungho Pak


    Various materials including glass and polymers have been widely used for stem cell culture due to their biocompatibility. However, the roles of these materials are fundamentally limited because they cannot realize or imitate the complex biological functions of living tissues, except in very simple cases. Here, the development of a bio-derived material suitable for stem cell culture and improvement of differentiation efficiency to specific cell lineages with no stimulating agents by using a chorion obtained from a fertilized zebrafish egg through the removal of the yolk and embryonic cell mass from the egg is reported. Mouse P19 EC stem cells introduced into the empty chorion form a uniform embryoid body (EB) without addition of any inducing agent. It is demonstrated that the zebrafish chorion with nanopores improves efficiencies greatly in the EB formation, cell proliferation, and lineage-specific differentiations compared to those of the conventional hanging drop culture method.

  20. Monitoring of Grandes Jorasses hanging glacier (Aosta Valley, Italy): improving monitoring techniques for glaciers instability

    Vagliasindi, Marco; Funk, Martin; Faillettaz, Jerome; Dalban, Pierre; Lucianaz, Claudio; Diotri, Fabrizio; Motta, Elena; Margreth, Stephan


    Grandes Jorasses serac is an unbalanced hanging glacier located on the south side of Mont Blanc Massif (Aosta Valley - Italy). It stands above Ferret Valley, a famous and most frequented touristic site both in winter and summer. Historical data and morphological evidences show that the glacier is subject to recurrent icefalls which can be dangerous especially in winter, as they can trigger catastrophic combined snow and ice avalanches. Serac dynamic was monitored in 1997-98 by prof. M Funk (ETH Zurich) by means of temperature and topographic measurement. These allowed to forecast the breakdown within a 2 days time. Thanks to a monitoring program, a new instability could be recognized in autumn 2008: a crevasse opening in the lower part of the hanging glacier. A new monitoring system was installed recently, consisting of stakes with prisms on serac surface and an automatic total station (theodolite plus distantiometer) sited on the valley floor. Monitoring is based on an empirically based power law (developed by ETH) that describes the increasing displacement rate before collapse. This monitoring system requires to measure displacement rate of the serac continuously. Although the topographic system is so far the method, it implies some troubles: (i) the difficulty in placing stakes on the steep and dangerous glacier surface; (ii) potential instability of stakes themselves due to snow pressure in winter and surface ice melting in summer; (iii) impossibility to carry out measurement in case of cloudy or stormy weather, which is rather a frequent situation on Grandes Jorasses peak. Moreover, hazard and risk management require some more informations, such as the instable ice mass volume. New technologies have been applied, and are still under test, to achieve a more reliable monitoring system and a better understanding of the serac dynamics. Close-range photogrammetry techniques have been used, allowing to process helicopter-taken images and obtain

  1. Total Gaussian curvature, drop shapes and the range of applicability of drop shape techniques.

    Saad, Sameh M I; Neumann, A Wilhelm


    Drop shape techniques are used extensively for surface tension measurement. It is well-documented that, as the drop/bubble shape becomes close to spherical, the performance of all drop shape techniques deteriorates. There have been efforts quantifying the range of applicability of drop techniques by studying the deviation of Laplacian drops from the spherical shape. A shape parameter was introduced in the literature and was modified several times to accommodate different drop constellations. However, new problems arise every time a new configuration is considered. Therefore, there is a need for a universal shape parameter applicable to pendant drops, sessile drops, liquid bridges as well as captive bubbles. In this work, the use of the total Gaussian curvature in a unified approach for the shape parameter is introduced for that purpose. The total Gaussian curvature is a dimensionless quantity that is commonly used in differential geometry and surface thermodynamics, and can be easily calculated for different Laplacian drop shapes. The new definition of the shape parameter using the total Gaussian curvature is applied here to both pendant and constrained sessile drops as an illustration. The analysis showed that the new definition is superior and reflects experimental results better than previous definitions, especially at extreme values of the Bond number.

  2. Hanging Maneuver for Stomach Traction in Laparoscopic Distal Pancreatic Resections: An Original Technique Applied in 218 Patients.

    Dokmak, Safi; Aussilhou, Béatrice; Ftériche, Fadhel Samir; Belghiti, Jacques; Sauvanet, Alain


    Stomach traction done to expose the pancreas is still a problem in laparoscopic left pancreatic resections. We developed a simple hanging maneuver to retract the stomach rapidly and effectively. After dividing the gastrocolic ligament, the stomach was encircled with a tape, turned along its horizontal axis and pulled with an epigastric trocar, which was later removed. This technique was used in all patients who underwent laparoscopic left pancreatic resections including 165 distal pancreatectomies (DP), 35 central pancreatectomies (CP) and 18 enucleations (En). Demographics, surgical and postoperative outcome data were recorded. There were no mortalities. The mean operative time for DP, CP and En were 174, 191 and 104 min, respectively. The transfusion (0-4%) and conversion (0-3%) rates were low for all procedures. Morbidity was mainly represented by pancreatic fistula and grades (B + C) for DP, CP and En were observed in 26, 22 and 17%, respectively. No complication related to hanging of the stomach, like gastric perforation, was observed. Re-intervention and the mean hospital stay for DP, CP and En were observed in 5, 11 and 0% and were 16, 22 and 12, respectively. The readmission rate was low (0-9%). Hanging maneuver of the stomach is a simple procedure to rapidly, safely and effectively retract the stomach during left laparoscopic pancreatic resections. © 2016 S. Karger AG, Basel.

  3. Advances in superheated drop (bubble) detector techniques

    d`Errico, F. [Pisa Univ. (Italy). Dipt. di Costruzioni Meccaniche e Nucleari; Alberts, W.G.; Matzke, M. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)


    State-of-the-art neutron dosemeters based on superheated drop (bubble) detectors are described. These are either active systems for area monitoring, which rely on the acoustical recording of drop vaporisations, or passive pen size ones for personal dosimetry, based on optical bubble counting. The technological solutions developed for the construction of robust devices for health physics applications are described with special emphasis on methods adopted to reduce mechanical shock and temperature sensitivity of the detectors. Finally, a review is given of some current research activities. In particular, a new approach to neutron spectrometry is presented which relies on the thermal effects for the definition of the response matrix of the system. (author).

  4. Electrochemical behavior of phytochelatins and related peptides at the hanging mercury drop electrode in the presence of cobalt(II) ions.

    Dorcák, Vlastimil; Sestáková, Ivana


    Direct current voltammetry and differential pulse voltammetry have been used to investigate the electrochemical behaviour of two phytochelatins: heptapeptide (gamma-Glu-Cys)3-Gly and pentapeptide (gamma-Glu-Cys)2-Gly, tripeptide glutathione gamma-Glu-Cys-Gly and its fragments: dipeptides Cys-Gly and gamma-Glu-Cys at the hanging mercury drop electrode in the presence of cobalt(II) ions. Most interesting results were obtained with direct current voltammetry in the potential region of -0.80 V up to -1.80 V. Differential pulse voltammetry of the same solutions of Co(II) with peptides gives more complicated voltammograms with overlapping peaks, probably in connection with the influence of adsorption at slow scan rates necessarily used in this method. However, in using Brdicka catalytic currents for analytical purposes, differential pulse voltammograms seem to be more helpful. Presented investigations have shown that particularly the prewave of cobalt(II) allows distinguishing among phytochelatins, glutathione, and its fragments.

  5. In vitro culture of early secondary preantral follicles in hanging drop of ovarian cell-conditioned medium to obtain MII oocytes from outbred deer mice.

    Choi, Jung Kyu; Agarwal, Pranay; He, Xiaoming


    The ovarian follicle (each contains a single oocyte) is the fundamental functional tissue unit of mammalian ovaries. In humans, it has been long held true that females are born with a maximum number of follicles (or oocytes) that are not only nonrenewable, but also undergoing degeneration with time with a sharply decreased oocyte quality after the age of ∼35. Therefore, it is of importance to isolate and bank ovarian follicles for in vitro culture to obtain fertilizable oocytes later, to preserve the fertility of professional women who may want to delay childbearing, young and unmarried women who may lose gonadal function because of exposure to environmental/occupational hazards or aggressive medical treatments, such as radiation and chemotherapy, and even endangered species and breeds. Although they contributed significantly to the understanding of follicle science and biology, most studies reported to date on this topic were done using the man-made, unnatural inbred animal species. It was found in this study that the conventional two-dimensional microliter drop and three-dimensional hanging drop (HD) methods, reported to be effective for in vitro culture of preantral follicles from inbred mice, are not directly transferrable to outbred deer mice. Therefore, a modified HD method was developed in this study to achieve a much higher (>5 times compared to the best conventional methods) percentage of developing early secondary preantral follicles from the outbred mice to the antral stage, for which, the use of an ovarian cell-conditioned medium and multiple follicles per HD were identified to be crucial. It was further found that the method for in vitro maturation of oocytes in antral follicles obtained by in vitro culture of preantral follicles could be very different from that for oocytes in antral follicles obtained by hormone stimulation in vivo. Therefore, this study should provide important guidance for establishing effective protocols of in vitro follicle

  6. Hang Gliders


    Francis M. Rogallo and his wife Gertrude researched flexible controllable fabric airfoils with a delta, V-shaped, configuration for use on inexpensive private aircraft. They were issued a flex-wing patent and refined their designs. Development of Rogallo wings, used by U.S. Moyes, Inc. substantially broadened the flexible airfoil technology base which originated from NASA's reentry parachute. The Rogallo technology, particularly the airfoil frame was incorporated in the design of a kite by John Dickenson. The Dickenson kite served as prototype for the Australian Moyes line of hang gliders. Company no longer exists.

  7. A novel fabrication technique for free-hanging homogeneous polymeric cantilever waveguides

    Nordström, M.; Calleja, M.; Hübner, Jörg;


    We present a novel bonding technique developed for the fabrication of a cantilever-based biosensing system with integrated optical read-out. The read-out mechanism is based on single-mode waveguides fabricated monolithically in SU-8. For optimal operation of the read-out mode, the cantilever wave...

  8. Effect of drop jump technique on the reactive strength index

    Struzik Artur


    Full Text Available The basic drill of plyometric training aimed at improving lower limb power and jump height is a drop jump. This exercise can be performed using different techniques, which substantially affects jump variables. Therefore, the aim of this study was to compare the values of the reactive strength index (RSI for countermovement drop jumps (CDJs and bounce drop jumps (BDJs. The study was carried out in a group of 8 male youth basketball players. The tests were conducted using the AMTI BP600900 force plate to measure ground reaction forces and the Noraxon MyoMotion system to record kinematic data. Each player performed two CDJs and two BDJs from the height of 15, 30, 45 and 60 cm. The RSI was calculated as a ratio of jump height and contact time. Moreover, the RSI was determined for the amortization and take-off phases separately. Significant differences (p < 0.05 between RSI values for CDJs and BDJs were recorded for jumps from 30, 45 and 60 cm. Differences in RSI values for jumps from 15 cm were not significant. Furthermore, CDJ height values were significantly higher (p < 0.05 than the values recorded for BDJs. Times of contact, amortization and take-off during BDJs were significantly shorter (p < 0.05 than the respective values obtained for CDJs. Therefore, the use of the RSI to monitor plyometric training should be based on the drop jump technique that is commonly performed by basketball players.

  9. Axisymmetric drop shape analysis-constrained sessile drop (ADSA-CSD): a film balance technique for high collapse pressures.

    Saad, Sameh M I; Policova, Zdenka; Acosta, Edgar J; Neumann, A Wilhelm


    Collapse pressure of insoluble monolayers is a property determined from surface pressure/area isotherms. Such isotherms are commonly measured by a Langmuir film balance or a drop shape technique using a pendant drop constellation (ADSA-PD). Here, a different embodiment of a drop shape analysis, called axisymmetric drop shape analysis-constrained sessile drop (ADSA-CSD) is used as a film balance. It is shown that ADSA-CSD has certain advantages over conventional methods. The ability to measure very low surface tension values (e.g., drop setup, and leak-proof design make the constrained sessile drop constellation a better choice than the pendant drop constellation in many situations. Results of compression isotherms are obtained on three different monolayers: octadecanol, dipalmitoyl-phosphatidyl-choline (DPPC), and dipalmitoyl-phosphatidyl-glycerol (DPPG). The collapse pressures are found to be reproducible and in agreement with previous methods. For example, the collapse pressure of DPPC is found to be 70.2 mJ/m2. Such values are not achievable with a pendant drop. The collapse pressure of octadecanol is found to be 61.3 mJ/m2, while that of DPPG is 59.0 mJ/m2. The physical reasons for these differences are discussed. The results also show a distinctive difference between the onset of collapse and the ultimate collapse pressure (ultimate strength) of these films. ADSA-CSD allows detailed study of this collapse region.

  10. Techniques for Generating Centimetric Drops in Microgravity and Application to Cavitation Studies

    Kobel, Philippe; de Bosset, Aurèle; Dorsaz, Nicolas; Farhat, M


    This paper describes the techniques and physical parameters used to produce stable centimetric water drops in microgravity, and to study single cavitation bubbles inside such drops (Parabolic Flight Campaigns, European Space Agency ESA). While the main scientific results have been presented in a previous paper, we shall herein provide the necessary technical background, with potential applications to other experiments. First, we present an original method to produce and capture large stable drops in microgravity. This technique succeeded in generating quasi-spherical water drops with volumes up to 8 ml, despite the residual g-jitter. We find that the equilibrium of the drops is essentially dictated by the ratio between the drop volume and the contact surface used to capture the drop, and formulate a simple stability criterion. In a second part, we present a setup for creating and studying single cavitation bubbles inside those drops. In addition, we analyze the influence of the bubble size and position on the...

  11. Interferometric technique for nanoscale dynamics of fluid drops on arbitrary substrates

    Verma, Gopal; Pandey, Mrityunjay; Singh, Kamal P.


    We demonstrate a simple interferometric probe to detect nanoscale dynamics of sessile fluid drops on arbitrary rough or flexible substrates. The technique relies on producing high-contrast Newton-ring like dynamical fringes by interference between a weak Fresnel reflection from the air-fluid interface of the drop and an air-glass interface of a convex lens placed above the drop in quasi-normal geometry. By analyzing the dynamical fringes, we observed 100-700 nm/s fluctuations in water drops evaporating on metal, leaves, insect wing, and sand paper due to their surface roughness. Similar fluctuations were also observed during spreading of non-volatile glycerin drops on various rough surfaces. Another application of the technique is demonstrated in precision measurement of change in evaporation rate of a water drop due to cooling of a metal substrate. This technique can be further miniaturized with a microscope objective with potential for wide applications.

  12. IR Drop Analysis and Its Reduction Techniques in Deep Submicron Technology

    Vanpreet Kaur


    Full Text Available This paper presents a detailed conceptual analysis of IR Drop effect in deep submicron technologies and its reduction techniques. The IR Drop effect in power/ground network increases rapidly with technology scaling. This affects the timing of the design and hence the desired speed. It is shown that in present day designs, using well known reduction techniques such as wire sizing and decoupling capacitor insertion, may not be sufficient to limit the voltage fluctuations and hence, two more important methods such as selective glitch reduction technique and IR Drop reduction through combinational circuit partitioning are discussed and the issues related to all the techniques are revised.

  13. Hang Gliders for Sport


    Hang gliding is growing rapidly. Free Flight produces 1,000 gliders a month and other companies are entering the field. Wing is simple to control, pulling back on control bar allows you to pick up speed and at the same time lowers your altitude. Pushing forward slows your speed and levels you off. Birdmen can choose from prone, upright or swing seat harnesses in either kits or ready-to-fly gliders.

  14. Water collection behavior and hanging ability of bioinspired fiber.

    Hou, Yongping; Chen, Yuan; Xue, Yan; Zheng, Yongmei; Jiang, Lei


    Since the water-collecting ability of the wetted cribellate spider capture silk is the result of a unique fiber structure, bioinspired fibers have been researched significantly so as to expose a new water-acquiring route in fogging-collection projects. However, the design of the geometry of bioinspired fiber is related to the ability of hanging drops, which has not been investigated in depth so far. Here, we fabricate bioinspired fibers to investigate the water collection behavior and the influence of geometry (i.e., periodicity of spindle knot) on the hanging-drop ability. We especially discuss water collection related to the periodicity of geometry on the bioinspired fiber. We reveal the length of the three phase contact line (TCL) at threshold conditions in conjunction with the maximal volume of a hanging drop at different modes. The study demonstrates that the geometrical structure of bioinspired fiber induces much stronger water hanging ability than that of uniform fiber, attributed to such special geometry that offers effectively an increasing TCL length or limits the contact length to be shorted. In addition, the geometry also improves the fog-collection efficiency by controlling tiny water drops to be collected in the large water drops at a given location.

  15. The Physics of Hang Gliding

    Hewett, Lionel D.


    Dr. Hewett has received both national and international awards from the hang gliding community for his contributions to the safety of towing hang gliders. These contributions were a consequence of his applying his knowledge of physics to the sport of hang gliding. This lecture illustrates how these and other applications of the fundamental principles of physics have influenced the historical evolutions of hang gliding and paragliding from the earliest flights of Otto Lilienthal in 1891 through the more recent record breaking flights of more than 430 miles from Zapata Texas.

  16. Development of measurement technique of large negative reactivity by an inverse kinetics rod drop method

    Takahashi, Hiroyuki; Takeuchi, Mitsuo; Murayama, Yoji [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment


    The determination of the large negative reactivity by a rod drop method is conducted by the change of the average neutron density in the core between the critical condition at constant power and the deep subcritical condition. The neutron density is measured with a neutron detector which output the pulse or electric current signal without time delay. If an electric-current-output neutron detector is used for the measurement, a logarithmic amplifier is required to measure over a wide range of neutron density of more than 3 digits and the time delay characteristic of the amplifier may badly influence the measurement results. The authors developed a measurement technique with an inverse kinetics rod drop (IKRD) method compensating the time delay characteristic of a logarithmic amplifies, and confirmed the validity and high precision of the technique by applying it to the measurement data obtained in the characteristic experiments of the JRR-3M silicide core. (author)

  17. Hang-It-Up Artists

    Szekely, George


    The best lesson ideas often derive from childhood recollections. When brought to class, play memories and art mementos from the teacher's childhood paint a powerful homage to children's art. A survey of a child's room in the dark, or with lights on, discloses interesting hanging sites, means of attachment and unusual items drafted for hanging, all…

  18. Homicidal hanging masquerading as suicide

    Leth, Peter Mygind; Charles, Annie Vesterby


    Homicidal hanging is rare and presents special problems for the forensic pathologist. We report a case of homicide by hanging masquerading as suicide, in which the forensic evidence was of crucial importance. The victim was a 61 years old man, who was found in his house suspended by a rope around...

  19. Homicidal hanging masquerading as suicide

    Leth, Peter Mygind; Charles, Annie Vesterby


    Homicidal hanging is rare and presents special problems for the forensic pathologist. We report a case of homicide by hanging masquerading as suicide, in which the forensic evidence was of crucial importance. The victim was a 61 years old man, who was found in his house suspended by a rope around...

  20. Verifying the Hanging Chain Model

    Karls, Michael A.


    The wave equation with variable tension is a classic partial differential equation that can be used to describe the horizontal displacements of a vertical hanging chain with one end fixed and the other end free to move. Using a web camera and TRACKER software to record displacement data from a vibrating hanging chain, we verify a modified version…

  1. Creation of a contusion injury in rabbit skeletal muscle using a drop-mass technique

    Margaret N. Deane


    Full Text Available This study reports our experience in developing a simple, minor injury. After reviewing the literature, a ‘drop-mass’ method was selected where a 201 g, elongated oval-shaped weight was dropped up to 15 times through a 1 m tube onto the left vastus lateralis of New Zealand white rabbits. To determine the extent of injury and degree of healing, biopsies were obtained six days after injury from the healing vastus lateralis of each animal. The tissue was fixed in formal saline, embedded in wax, cut and stained with haematoxylin and eosin (H&E and phosphotungstic acid haematoxylin (PTAH and examined by light microscopy (LM. The ‘optimal’ injury was created after seven drops, where quite severe, mild and moderately severe trauma was caused to muscle in the juxta-bone, mid and sub-dermal regions respectively. In each region, the muscle exhibited features of healing six days after injury. The ‘drop-mass’ technique appears to cause a contusion within a single muscle of at least three degrees of severity. This previously unreported observation is of particular importance to other researchers wishing to investigate contusion injury in other animal models.

  2. Trypan blue staining of the anterior capsule: the one-drop technique.

    Caporossi, Aldo; Balestrazzi, Angelo; Alegente, Marco; Casprini, Fabrizio; Caporossi, Tomaso


    Capsule staining is usually a two- or three-stage procedure in which trypan blue is injected under air, a viscoelastic device, viscoelastic mixed with dye, or compartmentalized viscoelastic and balanced salt solution. In these techniques, the consequent irrigation of the anterior chamber with balanced salt solution may lead to a less stable anterior chamber, a decrease of pupil diameter, and damage of the corneal endothelium. A modification of current injection techniques for staining the anterior capsule under a dispersive viscoelastic device with 1 drop of trypan blue by an ordinary 27-gauge anterior chamber cannula is described.

  3. Search for Free Fractional Electric Charge Elementary Particles Using an Automated Millikan Oil Drop Technique

    Halyo, V.; Kim, P.; Lee, E. R.; Lee, I. T.; Loomba, D.; Perl, M. L.


    We have carried out a direct search in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied--about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16e (e being the magnitude of the electron charge) from the nearest integer charge is less than 4.71x10{sup -22} particles per nucleon with 95% confidence. (c) 2000 The American Physical Society.

  4. Search for Free Fractional Electric Charge Elementary Particles Using an Automated Millikan Oil Drop Technique

    Halyo, V.; Kim, P.; Lee, E. R.; Lee, I. T.; Loomba, D.; Perl, M. L.


    We have carried out a direct search in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied-about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16e ( e being the magnitude of the electron charge) from the nearest integer charge is less than 4.71×10-22 particles per nucleon with 95% confidence.

  5. Railway crossing risk area detection using linear regression and terrain drop compensation techniques.

    Chen, Wen-Yuan; Wang, Mei; Fu, Zhou-Xing


    Most railway accidents happen at railway crossings. Therefore, how to detect humans or objects present in the risk area of a railway crossing and thus prevent accidents are important tasks. In this paper, three strategies are used to detect the risk area of a railway crossing: (1) we use a terrain drop compensation (TDC) technique to solve the problem of the concavity of railway crossings; (2) we use a linear regression technique to predict the position and length of an object from image processing; (3) we have developed a novel strategy called calculating local maximum Y-coordinate object points (CLMYOP) to obtain the ground points of the object. In addition, image preprocessing is also applied to filter out the noise and successfully improve the object detection. From the experimental results, it is demonstrated that our scheme is an effective and corrective method for the detection of railway crossing risk areas.

  6. Railway Crossing Risk Area Detection Using Linear Regression and Terrain Drop Compensation Techniques

    Wen-Yuan Chen


    Full Text Available Most railway accidents happen at railway crossings. Therefore, how to detect humans or objects present in the risk area of a railway crossing and thus prevent accidents are important tasks. In this paper, three strategies are used to detect the risk area of a railway crossing: (1 we use a terrain drop compensation (TDC technique to solve the problem of the concavity of railway crossings; (2 we use a linear regression technique to predict the position and length of an object from image processing; (3 we have developed a novel strategy called calculating local maximum Y-coordinate object points (CLMYOP to obtain the ground points of the object. In addition, image preprocessing is also applied to filter out the noise and successfully improve the object detection. From the experimental results, it is demonstrated that our scheme is an effective and corrective method for the detection of railway crossing risk areas.

  7. Manipulation of Contact Angles and Interfacial Lengths of Liquid Drops using Electro-Kinetic Techniques

    Zhou, X.; Nolte, D. D.; Pyrak-Nolte, L. J.


    Traditionally, capillary pressure is determined by increasing or decreasing external fluid pressures to change the immiscible fluid saturation in a porous medium. The resulting saturation and interfacial area are then linked to the capillary pressure through constitutive equations. A key question is whether externally measured pressures are sensitive to changes in distributions that arise from internal changes in contact angles. As a first step in addressing this question, we investigated the effect of electro-kinetic manipulation on interfacial area and contact angles for a fixed saturation. An EWOD (electro-wetting on dielectric) technique was used to alter the contact angle of single 10 μL droplets of a 1M KCl-H2O solution. A liquid droplet was placed on a glass cover slip (18 mm x 18 mm) coated with a layer of silver (100 nm in thickness) to act as an electrode and then spin-coated with polyimide (a dielectric). A platinum wire was inserted into the droplet and connected to an AC voltage source. The glass plate electrode was connected to ground. Measurements were made for Vrms voltages between 0 to 300 V at a frequency of 50 Hz. Two CCD cameras were used to image changes in the shape of a droplet. One camera was placed on a microscope to capture a top view of a drop in order to measure changes in areal extent and the perimeter of the drop. The second camera imaged a drop from the side to measure contact angles and side-view areal extent and perimeter. At low voltages, the cosine of the contact angle, θ, after applying voltage was linearly dependent on Vrms2. Several experiments showed that the slope of the low-voltage relationship of cos θ vs Vrms2 remained constant for all trials. As the voltage increased, the contact angle saturated. From the side-view images, the contact angle and interfacial length decreased with increasing voltage. From the top-view images, the drop shape changed from circular to elliptical-to irregular as the voltage increased

  8. Wind Turbines Support Techniques during Frequency Drops — Energy Utilization Comparison

    Ayman B. Attya


    Full Text Available The supportive role of wind turbines during frequency drops is still not clear enough, although there are many proposed algorithms. Most of the offered techniques make the wind turbine deviates from optimum power generation operation to special operation modes, to guarantee the availability of reasonable power support, when the system suffers frequency deviations. This paper summarizes the most dominant support algorithms and derives wind turbine power curves for each one. It also conducts a comparison from the point of view of wasted energy, with respect to optimum power generation. The authors insure the advantage of a frequency support algorithm, they previously presented, as it achieved lower amounts of wasted energy. This analysis is performed in two locations that are promising candidates for hosting wind farms in Egypt. Additionally, two different types of wind turbines from two different manufacturers are integrated. Matlab and Simulink are the implemented simulation environments.

  9. A robust calibration technique for acoustic emission systems based on momentum transfer from a ball drop

    McLaskey, Gregory C.; Lockner, David A.; Kilgore, Brian D.; Beeler, Nicholas M.


    We describe a technique to estimate the seismic moment of acoustic emissions and other extremely small seismic events. Unlike previous calibration techniques, it does not require modeling of the wave propagation, sensor response, or signal conditioning. Rather, this technique calibrates the recording system as a whole and uses a ball impact as a reference source or empirical Green’s function. To correctly apply this technique, we develop mathematical expressions that link the seismic moment $M_{0}$ of internal seismic sources (i.e., earthquakes and acoustic emissions) to the impulse, or change in momentum $\\Delta p $, of externally applied seismic sources (i.e., meteor impacts or, in this case, ball impact). We find that, at low frequencies, moment and impulse are linked by a constant, which we call the force‐moment‐rate scale factor $C_{F\\dot{M}} = M_{0}/\\Delta p$. This constant is equal to twice the speed of sound in the material from which the seismic sources were generated. Next, we demonstrate the calibration technique on two different experimental rock mechanics facilities. The first example is a saw‐cut cylindrical granite sample that is loaded in a triaxial apparatus at 40 MPa confining pressure. The second example is a 2 m long fault cut in a granite sample and deformed in a large biaxial apparatus at lower stress levels. Using the empirical calibration technique, we are able to determine absolute source parameters including the seismic moment, corner frequency, stress drop, and radiated energy of these magnitude −2.5 to −7 seismic events.

  10. The stopped-drop method: a novel setup for containment-free and time-resolved measurements

    Schiener, Andreas; Seifert, Soenke; Magerl, Andreas


    A novel setup for containment-free time-resolved experiments at a free-hanging drop is reported. Within a dead-time of 100 ms a drop of mixed reactant solutions is formed and the time evolution of a reaction can be followed from thereon by various techniques. As an example, a small-angle X-ray scattering study on the formation mechanism of EDTA-stabilized CdS both at a synchrotron and a laboratory X-ray source is presented here. While the evolution can be followed with one drop only at a synchrotron source, a stroboscopic mode with many drops is preferable for the laboratory source.

  11. Effect of substrates on naproxen-polyvinylpyrrolidone solid dispersions formed via the drop printing technique.

    Hsu, Hsin-Yun; Toth, Scott J; Simpson, Garth J; Taylor, Lynne S; Harris, Michael T


    Solid dispersions have been used to improve the bioavailability of poorly water-soluble drugs. However, drug solid-state phase, compositional uniformity, and scale-up problems are issues that need to be addressed. To allow for highly controllable products, the drop printing (DP) technique can provide precise dosages and predictable compositional uniformity of active pharmaceutical ingredients in two-/three-dimensional structures when integrated with edible substrates. With different preparation conditions, DP was conducted to fabricate naproxen (NAP)-polyvinylpyrrolidone solid dispersions with chitosan and hydroxypropyl methylcellulose films as the substrate. Scanning electron microscopy, X-ray diffraction, second harmonic generation microscopy, and atomic force microscopy analyses were performed to characterize the microstructure and spatial distribution of NAP in the solid dispersions. The results identified that composition, temperature, and substrate type all had an impact on morphology and crystallization of samples. The surface energy approach was combined with classical nucleation theory to evaluate the affinity between the nucleus of NAP and substrates. Finally, the collective results of the drug were correlated to the release profile of NAP within each sample.

  12. The capacitive drop tensiometer - a novel multianalysing technique for measuring the properties of liquids

    Wang, C. H.; Augousti, A. T.; Mason, J.; McMillan, N. D.


    A new instrumental method for measuring the physical properties of a liquid has been developed. The instrument, called a capacitive drop tensiometer (CDT), is based on the drop volume principle in combination with a capacitive transducer. A delivery head with a specialized wetting design was constructed for forming drops. The capacitive transducer uses the delivery head as one of its plates and a cylindrical ring plate, which surrounds the delivery head and the space occupied by the drop that is formed, as another. Excellent linearity is achieved by optimizing the design, with an accuracy of drop volume measurement of approximately 0957-0233/10/1/007/img6. The system is suitable for measuring both drops in equilibrium and those in the process of growing. Its capability of real-time measurement makes it particularly useful for volatile liquids, in which instance the measurement of drop volume using a flowmeter or a pump is no longer reliable. The CDT can also be used to determine concentration. It was found that the concentration curve is linear for aqueous glycerol solutions although not so for aqueous ethanol solutions. The CDT's ability to measure surface tension was also explored and experimental results are presented here.

  13. Length of a Hanging Cable

    Eric Costello


    Full Text Available The shape of a cable hanging under its own weight and uniform horizontal tension between two power poles is a catenary. The catenary is a curve which has an equation defined by a hyperbolic cosine function and a scaling factor. The scaling factor for power cables hanging under their own weight is equal to the horizontal tension on the cable divided by the weight of the cable. Both of these values are unknown for this problem. Newton's method was used to approximate the scaling factor and the arc length function to determine the length of the cable. A script was written using the Python programming language in order to quickly perform several iterations of Newton's method to get a good approximation for the scaling factor.

  14. 维生素C-悬滴法诱导小鼠胚胎干细胞分化为心肌细胞%Inducing the differentiation of mouse embryonic stem cells into cardiomyocytes by vitamin C-hanging drop method

    穆军升; 李献帅; 袁树民; 张健群; 伯平


    目的 利用维生素C作为诱导因子,采用悬滴法形成拟胚体,体外诱导小鼠胚胎干细胞分化为心肌细胞并检测其分化效率,同时确定这种诱导方法的最佳维生素C浓度.方法 复苏小鼠胚胎干细胞,传代培养后,消化离心后重悬细胞,用悬滴法形成拟胚体,用含1×10-3、1×10-4、1×10-5、1×10-6 mol/L 4种不同浓度维生素C的分化培养基对其进行诱导分化,以不添加任何诱导剂作为对照组,观察各组小鼠出现跳动拟胚体的数量,并计算分化效率;免疫荧光染色检测心肌细胞特异标志物肌钙蛋白T(cTnT);膜片钳实验检测心肌细胞自发性动作电位.结果 大量的自发跳动心肌细胞在诱导分化后12d左右开始出现.维生素C诱导小鼠胚胎干细胞分化为心肌细胞的最佳浓度为1×10-4 mol/L,其分化出现跳动拟胚体的百分比为81.25%,显著高于不加诱导剂的对照组(12.50%);跳动心肌细胞cTnT染色阳性;跳动心肌细胞检测到自发性动作电位.结论 最佳的维生素C浓度(1×10-4mol/L)能够明显提高体外悬滴法诱导小鼠胚胎干细胞分化为心肌细胞的效率.%Objective Using the vitamin C as inducers and hanging drop method to form embryoid bodies to induce the differentiation of mouse embryonic stem cells into cardiomyocytes in vitro and detecting its differentiation efficiency.Searching for the optimal concentration of vitamin C for this method.Methods Mouse embryonic stem cells were recovered,passaged,digested,centrifuged,suspended and form embryoid bodies by hanging drop method.The embryoid bodies were induced by differentiation medium containing various concentration of vitamin C (1 × 10-3,1 × 10-4,1 × 10-5,1 × 10-6 mol/L).Control group was not treated by inducer.The number of beating embryoid bodies were calculated.Staining the specific marker cardiac Troponin T (cTnT) of cardiomyocytes by immunofluorescence; Detecting the electrophysiological function of

  15. Hanging drop cultures of human testis and testis cancer samples

    Jørgensen, Anne; Young, J; Nielsen, J E


    limited by the lack of experimental models. The aim of this study was to establish an experimental tissue culture model to maintain normal and malignant germ cells within their niche and allow investigation of treatment effects. METHODS: Human testis and testis cancer specimens from orchidectomies were...

  16. Soft drop

    Larkoski, Andrew J. [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA 02139 (United States); Marzani, Simone [Institute for Particle Physics Phenomenology, Durham University,South Road, Durham DH1 3LE (United Kingdom); Soyez, Gregory [IPhT, CEA Saclay, CNRS URA 2306,F-91191 Gif-sur-Yvette (France); Thaler, Jesse [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA 02139 (United States)


    We introduce a new jet substructure technique called “soft drop declustering”, which recursively removes soft wide-angle radiation from a jet. The soft drop algorithm depends on two parameters — a soft threshold z{sub cut} and an angular exponent β — with the β=0 limit corresponding roughly to the (modified) mass drop procedure. To gain an analytic understanding of soft drop and highlight the β dependence, we perform resummed calculations for three observables on soft-dropped jets: the energy correlation functions, the groomed jet radius, and the energy loss due to soft drop. The β=0 limit of the energy loss is particularly interesting, since it is not only “Sudakov safe” but also largely insensitive to the value of the strong coupling constant. While our calculations are strictly accurate only to modified leading-logarithmic order, we also include a discussion of higher-order effects such as multiple emissions and (the absence of) non-global logarithms. We compare our analytic results to parton shower simulations and find good agreement, and we also estimate the impact of non-perturbative effects such as hadronization and the underlying event. Finally, we demonstrate how soft drop can be used for tagging boosted W bosons, and we speculate on the potential advantages of using soft drop for pileup mitigation.

  17. Evaluating surface energy components of asphalt binders using Wilhelmy Plate and Sessile Drop Techniques

    Bahramian, Anohe


    In this Study, the surface energy was investigated for six penetration grade 70/100 bitumen binders. Wilhelmy Plate and the Sessile Drop were used to determine the contact angles. The purpose of this study was to compare the Wilhelmy Plate method with the Sessile Drop method, and to compare the significance of Owens-Wendt model with the significance of Acid Base model by correlating surface energy components. Better R2 –values were found for surface energy components by using the Owens-Wendt ...

  18. Prediction of pressure drop in fluid tuned mounts using analytical and computational techniques

    Lasher, William C.; Khalilollahi, Amir; Mischler, John; Uhric, Tom


    A simplified model for predicting pressure drop in fluid tuned isolator mounts was developed. The model is based on an exact solution to the Navier-Stokes equations and was made more general through the use of empirical coefficients. The values of these coefficients were determined by numerical simulation of the flow using the commercial computational fluid dynamics (CFD) package FIDAP.

  19. Novel Method for Sizing Metallic Bottom Crack Depth Using Multi-frequency Alternating Current Potential Drop Technique

    Li Yuting


    Full Text Available Potential drop techniques are of two types: the direct current potential drop (DCPD technique and alternating current potential drop (ACPD technique, and both of them are used in nondestructive testing. ACPD, as a kind of valid method in sizing metal cracks, has been applied to evaluate metal structures. However, our review of most available approaches revealed that some improvements can be done in measuring depth of metal bottom crack by means of ACPD, such as accuracy and sensitivity of shallow crack. This paper studied a novel method which utilized the slope of voltage ratio-frequency curve to solve bottom crack depth by using a simple mathematic equation based on finite element analysis. It is found that voltage ratio varies linearly with frequency in the range of 5-15 Hz; this range is slightly higher than the equivalent frequency and lower than semi-permeable frequency. Simulation and experiment show that the novel method can measure the bottom crack depth accurately.

  20. Automatic hanging protocol for chest radiographs

    Luo, Hui; Hao, Wei; Cornelius, Craig


    Chest radiography is one of the most widely used techniques in diagnostic imaging. It makes up at least one third of all conventional diagnostic radiographic procedures in hospitals. However, in both film-screen and computed radiography, images are often digitized with the view and orientation unknown or mislabeled, which causes inefficiency in displaying them in the picture archive and communication system (PACS). Hence, the goal of this work is to provide a robust, efficient, and automatic hanging protocol for chest radiographs. To achieve it, the method star ts with recognition by extracting a set of distinctive features from chest radiographs. Next, a well-defined probabilistic classifier is used to train and classify the radiographs. Identifying the orientation of the radiographs is performed by an efficient algorithm which locates the neck, heart, and abdomen positions in radiographs. The initial experiment was performed on radiographs collected from daily routine chest exams in hospitals, and it has shown promising results.

  1. In vitro water wettability of silicone hydrogel contact lenses determined using the sessile drop and captive bubble techniques.

    Maldonado-Codina, Carole; Morgan, Philip B


    This study investigated the water contact angles of five commercially available silicone hydrogel contact lenses (Acuvue Advance, Acuvue Oasys, Focus Night & Day, O2 Optix, and PureVision) using sessile drop and captive bubble techniques. The only lens type that showed a significant difference in water contact angle when measured by sessile drop direct from the blister compared with after 48 h of soaking/washing in saline was the Acuvue Advance lens (from 66 degrees to 96 degrees, respectively) (p=0.0002), presumably because of surface active agents within the blister solution. The water contact angle data split the lenses into two distinct groups (psessile drop measures and relatively low captive bubble values (thereby displaying significant hysteresis) whereas the Focus Night & Day and O2 Optix lenses showed relatively low sessile drop measures and relatively high captive bubble values (with little hysteresis). Contact angle analysis of hydrogel lens surfaces is highly methodologically dependent and may be able to predict the clinical performance of contact lenses in vivo.

  2. Soft Drop

    Larkoski, Andrew J; Soyez, Gregory; Thaler, Jesse


    We introduce a new jet substructure technique called "soft drop declustering", which recursively removes soft wide-angle radiation from a jet. The soft drop algorithm depends on two parameters--a soft threshold $z_\\text{cut}$ and an angular exponent $\\beta$--with the $\\beta = 0$ limit corresponding roughly to the (modified) mass drop procedure. To gain an analytic understanding of soft drop and highlight the $\\beta$ dependence, we perform resummed calculations for three observables on soft-dropped jets: the energy correlation functions, the groomed jet radius, and the energy loss due to soft drop. The $\\beta = 0$ limit of the energy loss is particularly interesting, since it is not only "Sudakov safe" but also largely insensitive to the value of the strong coupling constant. While our calculations are strictly accurate only to modified leading-logarithmic order, we also include a discussion of higher-order effects such as multiple emissions and (the absence of) non-global logarithms. We compare our analytic r...

  3. Investigation of the contact angles between various molten metals and substrates of niobium and zirconium. Final report. [Sessile drop technique

    Munir, Z.A.


    The sessile drop technique was utilized for the determination of the contact angles between droplets of liquid tin, indium, and gallium; and substrates of niobium and zirconium. Contact angles, theta, were measured for various substrate surface roughness and over the temperature range 30 to 650/sup 0/C. Values of theta for all of these systems were found to be greater than 90/sup 0/ i.e., constituting a case of nonwetting between the liquid metals and the substrates. Three characteristic regions of the temperature dependence of contact angles were observed. A steady-state region in which the contact angle is relatively independent of temperature was preceded and followed by regions in which theta decreased rapidly with increasing temperature. For the steady-state or second region, contact angles were found to be independent of time whereas in the third region contact angles showed a decreasing trend with time at constant temperature. In accordance with theoretical predictions for theta greater than 90/sup 0/, increasing roughness of the substrate caused a corresponding increase in theta. Electron microprobe analyses showed that only the Ga--Zr system exhibited evidence of diffusion at the interface. Photographs of the sessile drop of this system over a period of time indicated that the drop had spread over a greater area thus supporting the possibility of a surface diffusion mass-transport process.

  4. Medico-legal examination of hanging

    Mehmet Beşir Yıldırım


    Full Text Available Hanging is usually fatal and it is one of the most preferred method of suicide due to can be applied easily at any environment. In hanging particularly serious injuries is seen on the neck structures. Vascular injuries, cervical spine injury, laryngeal, tracheal injury can be seen or cerebral edema, intracranial hemorrhage can be occurred secondary to neck injury. In survivors of hanging, epilepsy, pulmonary complications such as acute respiratory distress syndrome, pulmonary edema, and bronchopneumonia are frequently observed. Hanging is a serious health problem that requires urgent intervention and post-professional care. Hanging has a high mortality despite early and accurate intervention. However the relief of neck structures and the treatment of accompanying complications can increase survival. In this study, we aimed that once again attract attention one of the most preferred way of suicide hanging cases, raise awareness of community on this issue and emphasize the importance of the early interventions in patients with near hanging. J Clin Exp Invest 2015; 6 (4: 400-405

  5. Hang cleans and hang snatches produce similar improvements in female collegiate athletes.

    Ayers, J L; DeBeliso, M; Sevene, T G; Adams, K J


    Olympic weightlifting movements and their variations are believed to be among the most effective ways to improve power, strength, and speed in athletes. This study investigated the effects of two Olympic weightlifting variations (hang cleans and hang snatches), on power (vertical jump height), strength (1RM back squat), and speed (40-yard sprint) in female collegiate athletes. 23 NCAA Division I female athletes were randomly assigned to either a hang clean group or hang snatch group. Athletes participated in two workout sessions a week for six weeks, performing either hang cleans or hang snatches for five sets of three repetitions with a load of 80-85% 1RM, concurrent with their existing, season-specific, resistance training program. Vertical jump height, 1RM back squat, and 40-yard sprint all had a significant, positive improvement from pre-training to post-training in both groups (p≤0.01). However, when comparing the gain scores between groups, there was no significant difference between the hang clean and hang snatch groups for any of the three dependent variables (i.e., vertical jump height, p=0.46; 1RM back squat, p=0.20; and 40-yard sprint, p=0.46). Short-term training emphasizing hang cleans or hang snatches produced similar improvements in power, strength, and speed in female collegiate athletes. This provides strength and conditioning professionals with two viable programmatic options in athletic-based exercises to improve power, strength, and speed.

  6. Comparison of TEAR and TFRC throughput for Drop tail and RED Queue Management Techniques

    Parminderjeet Singh


    Full Text Available The comparison of throughput for TEAR (TCP emulation at receivers and TFRC TCP friendly rate control in MANETs is done with varying Active queue Management Techniques. The analysis reveals that for bandwidth constraint links, TEAR and TFRC perform far better than normal traffic propagation through TCP. In case of TEAR, the processing and route congestion algorithm load is shared by the receiver resulting in lesser load at the transmitters. In TFRC the TCP traffic is propagated via an algorithm to curb acknowledgement congestions. The effect of these two techniques is monitored on Droptail and RED, two of the most common Active Queue Management Techniques.

  7. [Sensory illusions in hang-gliding].

    Bousquet, F; Bizeau, A; Resche-Rigon, P; Taillemite, J P; De Rotalier


    Sensory illusions in hang-gliding and para-gliding. Hang-gliding and para-gliding are at the moment booming sports. Sensory illusions are physiological phenomena sharing the wrong perception of the pilote's real position in space. These phenomena are very familiar to aeroplane pilotes, they can also be noticed on certain conditions with hang-gliding pilotes. There are many and various sensory illusions, but only illusions of vestibular origin will be dealt with in this article. Vestibular physiology is reminded with the working principle of a semicircular canal. Physiology and laws of physics explain several sensory illusions, especially when the pilote loses his visual landmarks: flying through a cloud, coriolis effect. Also some specific stages of hang-gliding foster those phenomena: spiraling downwards, self-rotation, following an asymetric closing of the parachute, spin on oneself. Therefore a previous briefing for the pilotes seems necessary.

  8. A High-Sensitivity Potential-Drop Technique for Fatigue Crack Growth Measurements,


    inappropriate to assume that crack growth characteristics at the surface are representative of crack behaviour in the specimen mid-thickness. 2.2 Ultrasonic...techniques has been described by several authors [23-25], and offers the advantages of high noise rejection and low current consumption . However, as the...Colonel B.C. Joshi, Military, Naval and Air Adviser, High Commission of India, Red Hill, A.C.T. Director, Defence Research Centre, Kuala Lumpur, Malaysia

  9. Musings: Childhood buddy hangs up

    Ajai R. Singh


    Full Text Available 'R' really was special. Shouldered the responsibility of a business family at a tender age. Worked over inefficient estate management by elders, saw to it younger siblings were settled, sacrificed youth to bring up business and family. Enjoyed friends, drinks, driving. We were childhood buddies from the same town. I had met him a couple of months before the incident. It was after nearly a decade. At a chemist's shop. He was buying medicines. Antidepressants. I asked him what happened. He had tears in his eyes. There was no flicker of the customary light on his face I had known so well. The smile that usually sparkled in his eye as he met an old childhood buddy had vanished. I could read the distress. I shook hands and told him to meet me in the clinic and we would sort it out. Depression is perfectly treatable, I said. Did you undergo psychotherapy? No, he said. Only drugs, but felt better. Some thoughts bothering you, I asked. Yes. Why not talk to your psychiatrist, I said. He thought for a moment, a long moment. I had never known 'R' to take that long to decide. Finally he said he would come and meet me in my clinic. Suddenly 'R' was dead. Died by hanging. I wondered what went wrong. Would I have saved him if I had got over my professional reserve and insisted he come for treatment? Was he really taking treatment with someone, or just self-medicating himself? I know he listened to me. If I had phoned him up, or his parents, and told them: nothing doing, I want to see 'R' well. Let him come to my clinic. Would that not have given him a chance to survive? Or even if he did commit the act, it would not be for want of trying. Some days later. As I neared his house while I was going to a neighbour's, I looked up at the forlorn structure. A grim board outside said, "Trespassers will be prosecuted". What about the late owner, who prosecuted me since I could not trespass a professional limitation: don't solicit patients.

  10. Elastomeric PDMS Planoconvex Lenses Fabricated by a Confined Sessile Drop Technique.

    Ekgasit, S; Kaewmanee, N; Jangtawee, P; Thammacharoen, C; Donphoongpri, M


    The ubiquity of high quality smartphones at affordable prices not only accelerated the social penetration in the global population but also promoted nontraditional usage of smartphones as point-of-care medical diagnostic devices, sensors, and portable digital microscopes. This paper reveals a simple, rapid, cost-effective, and template-free technique for mass-scale production of an elastomeric PDMS (ePDMS) planoconvex lens capable of converting a smartphone into a portable digital microscope. By taking advantage of the resistance to spreading of liquid by a sharp edge, highly stable spherical cap of viscous liquid PDMS (lPDMS) on a smooth PMMA circular disk was fabricated. The axisymmetric spreading of lPDMS under the gravitational force and interfacial tension force enable the formation of spherical cap with a certain radius of curvature. A thermal treatment at 80 °C for 30 min cured the spherical cap lPDMS into a bubble-free ePDMS planoconvex lens. Lenses with focal lengths of 55.2-3.4 mm could be reproducibly fabricated by adjusting the volume of dispensed lPDMSs and diameter of PMMA disks. High-resolution panoramic microscope images without a distortion of small cylindrical object could be constructed on-the-fly using the imbedded smartphone app. Applications of the smartphone digital microscope equipped with an ePDMS planoconvex lens for imaging of micro printings, gun shot residues, cylindrical objects, and bullet toolmarks were explored.

  11. CARD (Continuous and Random Dropping based DRDOS Attack Detection and Prevention Techniques in MANET

    Rupa Rani


    Full Text Available The DDOS is “distributed-denial-of-service” meaning many “zombies or daemons” computers performing a DOS (Denial of Service attack on one computer, usually directed by one “master”. In MANETs, DOS attacks not only consume the scarce system resources, such as bandwidth, battery energy, or CPU cycles, but also isolate legitimate users from a network. The DOS attacks may impact the network connectivity seriously and may further undermine the networking functions. In DRDOS attacks, the victim is bombarded by reflected response packets from legitimate communicating nodes, and thus it is difficult to distinguish attack packets from legitimate packets. In this paper, we propose a defense mechanism based on CARD based DRDOS attack detection and prevention techniques in MANET. The proposed rate limiting scheme will penalize the different attackers based on their rate limits and server load. The victim end defense system decrease the rate limit exponentially & increase it linearly based on the attack traffic rate. Finally this approach is discussed in three phases as detection, control and prevention which is explained in CARD detection architecture.

  12. Comparison of the lateral retention forces on sessile and pendant water drops on a solid surface

    de la Madrid, Rafael; Whitehead, Taylor; Irwin, George M.


    We present a simple experiment that demonstrates how a water drop hanging from a Plexiglas surface (pendant drop) experiences a lateral retention force that is comparable to, and in some cases larger than, the lateral retention force on a drop resting on top of the surface (sessile drop). The experiment also affords a simple demonstration of the Coriolis effect in two dimensions.

  13. Comparison of the lateral retention forces on sessile and pendant water drops on a solid surface

    de la Madrid, Rafael; Whitehead, Taylor; Irwin, George


    We present a simple experiment that demonstrates how a water drop hanging from a Plexiglas surface (pendant drop) experiences a lateral retention force that is comparable to, and in some cases larger than, the lateral retention force on a drop resting on top of the surface (sessile drop). The experiment also affords a simple demonstration of the Coriolis effect in two dimensions.

  14. Near hanging: Early intervention can save lives

    Ritika Gandhi


    Full Text Available Hanging is a common method of suicide/homicide in the Indian scenario. We report three successive cases of attempted suicidal hangings seen over a period of 4 months in our intensive care wards. All of them presented gasping with poor clinical status and required immediate intubation, resuscitation, assisted ventilation and intensive care treatment. None had cervical spine injury, but one patient developed aspiration pneumonia. All the three patients received standard supportive intensive care and made full clinical recovery without any neurological deficit. We conclude that the cases of near hanging should be aggressively resuscitated and treated irrespective of dismal initial presentation. This is well supported by the excellent outcomes in our cases despite their poor initial condition.

  15. Flat nose low velocity drop-weight impact response of carbon fibre composites using non-destructive damage detection techniques

    Farooq, Umar; Myler, Peter


    This work is mainly concerned with the nondestructive post-impact damage evaluation of carbon fibre reinforced laminated composite panels subject to low velocity drop-weight impact by flat and round nose impactors. Quasi-isotropic laminates consisting of eight-, sixteen-, and twenty-four plies were impacted by flat and round nose impactors at different velocity levels. Load-time history data were recorded and plotted to correlate loaddrop as damage level to the impactor nose profiles. Test produced data, non-destructive damage detection techniques: visual, ultrasonic, and eddy- current, and computer simulations were utilised to identify and quantify status of the impact induced damage. To evaluate damage in relatively thick laminates (consisting of 24-Ply), the damage ratios and deflection quantities were correlated to the corresponding impactor nose profiles. Damage induced by the flat nose impactor to thick laminates was compared against the data produced by the round nose impactor. Results show that relatively thin laminates were largely affected by the impactor nose. Reasonable difference was observed in damage caused by flat and round impactor nose profiles to thick laminates impacted at relatively higher velocity impacts. Resultswere compared and validated against simulation produced data.

  16. Effects of drop size and measuring condition on static contact angle measurement on a superhydrophobic surface with goniometric technique

    Seo, Kwangseok; Kim, Minyoung; Kim, Do Hyun [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Ahn, Jeong Keun [Chungnam National University, Daejeon (Korea, Republic of)


    It is not a simple task to measure a contact angle of a water drop on a superhydrophobic surface with sessile drop method, because a roll-off angle is very low. Usually contact angle of a water drop on a superhydrophobic surface is measured by fixing a drop with intentional defects on the surface or a needle. We examined the effects of drop size and measuring condition such as the use of a needle or defects on the static contact angle measurement on superhydrophobic surface. Results showed that the contact angles on a superhydrophobic surface remain almost constant within intrinsic measurement errors unless there is a wetting transition during the measurement. We expect that this study will provide a deeper understanding on the nature of the contact angle and convenient measurement of the contact angle on the superhydrophobic surface.




    Full Text Available Survival after nylon rope suicidal hanging is a rare occurance . We describe here a patient who attempted suicide by nylon rope hanging and developed post obstructive pulmonary edema was managed successfully . Patient recovered completely with ventilatory support in next 60 hours without any neurological deficit.This case highlights an unusual complication of hanging and its recovery.


    Ghindora Ghanshayam L


    Full Text Available The selected marketed mouthwash formulations was carried out using Traube’s stalagmometer technique by drop number method to determine their individual surface tension for further identification, structure elucidation and chemical constituents. The formulation I (Potassium nitrate & sodium fluoride, formulation II (Chlorhexidine gluconate, formulation III (Thymol, eucalyptol and menthol were selected for the case study. These formulations were also evaluated to their same quantity mixture ratio with distilled water combination for estimation of different percent composition. The main aim and rationale of the study was to evaluate the surface tension of three selected formulations with distilled water. In individual surface tension study, it was noted that formulation II (48.29 dyne/cm showed highest value and formulation III (40.81 dyne/cm showed lowest value comparison between the three formulations under laboratory conditions. The 50% formulation mixture with distilled water showed minimum surface tension (49.20 dyne/cm and 90% formulation mixture with distilled water showed maximum surface tension (54.30 dyne/cm amongst other composition. In our present study, all the percent composition values were less than standard surface tension value. The 20% (50.31 dyne/cm, 70% (50.64 dyne/cm, 80% (50.26 dyne/cm and 30% (49.30 dyne/cm, 50% (49.20 dyne/cm and also 40% (51.73 dyne/cm, 60% (51.26 dyne/cm formulation mixture with distilled water showed approximately same surface tension values.

  19. Pascal's wager and the hanging of crepe.

    Siegler, M


    Hanging of crepe refers to one type of strategy employed by physicians in communicating prognoses to families of critically ill patients. This approach offers the bleakest, most pessimistic prediction of the patient's outcome, presumably in an effort to lessen the family's suffering if the patient dies of his illness. Certain similarities exist between this technic and that used by Pascal, the 17th-century philosopher, in formulating his wager on the belief in God, in that both attempt to develop "no-lose" strategies, in which chances for "winning" are maximized. A detailed analysis of these strategies indicates that neither is truly "no-lose," and that both contain inherent disadvantages. Prognostication, an alternative approach to physician-family communication, appears to be strategically and morally superior to the hanging-of-crepe strategy.

  20. Wireless Orbiter Hang-Angle Inclinometer System

    Lucena, Angel; Perotti, Jose; Green, Eric; Byon, Jonathan; Burns, Bradley; Mata, Carlos; Randazzo, John; Blalock, Norman


    A document describes a system to reliably gather the hang-angle inclination of the orbiter. The system comprises a wireless handheld master station (which contains the main station software) and a wireless remote station (which contains the inclinometer sensors, the RF transceivers, and the remote station software). The remote station is designed to provide redundancy to the system. It includes two RF transceivers, two power-management boards, and four inclinometer sensors.

  1. On the Rod Drop technique in integral reactivity measures in control banks and reactor safety; Sobre a tecnica de Rod Drop em medidas de reatividade integral em bancos de controle e seguranca de reatores

    Stefani, Giovanni Laranjo


    This work presents a study on the effect of shading in neutron detectors, when used in measures of reactivity with the rod drop technique. Shading can be understood as a change in the efficiency of the detectors, when it is given in detected neutrons fission occurred in the reactor, more evident in the detectors closest to the bank being inserted. The method of analysis was based on simulations of reactor IPEN/MB-01, using the code CITATION and MCNP program. In both cases, the results were static, showing Neutronic flows in only two situations: before insertion of the control rod and after insertion. The measure of reactivity in this case was achieved using the expression derived from the source jerk technique. In addition to theoretical study, data from a rod drop experiment conducted in the reactor IPEN/MB-01 were also used. In this case, the reactivity was obtained using inverse kinetic method, since experimental data were set of values that vary with time. In all cases, correction factors for the shadowing effect have been proposed. (author)

  2. Bubble and drop interfaces



    The book aims at describing the most important experimental methods for characterizing liquid interfaces, such as drop profile analysis, bubble pressure and drop volume tensiometry, capillary pressure technique, and oscillating drops and bubbles. Besides the details of experimental set ups, also the underlying theoretical basis is presented in detail. In addition, a number of applications based on drops and bubbles is discussed, such as rising bubbles and the very complex process of flotation. Also wetting, characterized by the dynamics of advancing contact angles is discussed critically. Spec

  3. Drag on Sessile Drops

    Milne, Andrew J. B.; Fleck, Brian; Nobes, David; Sen, Debjyoti; Amirfazli, Alidad; University of Alberta Mechanical Engineering Collaboration


    We present the first ever direct measurements of the coefficient of drag on sessile drops at Reynolds numbers from the creeping flow regime up to the point of incipient motion, made using a newly developed floating element differential drag sensor. Surfaces of different wettabilities (PMMA, Teflon, and a superhydrophobic surface (SHS)), wet by water, hexadecane, and various silicone oils, are used to study the effects of drop shape, and fluid properties on drag. The relation between drag coefficient and Reynolds number (scaled by drop height) varies slightly with liquid-solid system and drop volume with results suggesting the drop experiences increased drag compared to similar shaped solid bodies due to drop oscillation influencing the otherwise laminar flow. Drops adopting more spherical shapes are seen to experience the greatest force at any given airspeed. This indicates that the relative exposed areas of drops is an important consideration in terms of force, with implications for the shedding of drops in applications such as airfoil icing and fuel cell flooding. The measurement technique used in this work can be adapted to measure drag force on other deformable, lightly adhered objects such as dust, sand, snow, vesicles, foams, and biofilms. The authours acknowledge NSERC, Alberta Innovates Technology Futures, and the Killam Trusts.

  4. Common Cause Case Study: An Estimated Probability of Four Solid Rocket Booster Hold-Down Post Stud Hang-ups

    Cross, Robert


    Until Solid Rocket Motor ignition, the Space Shuttle is mated to the Mobil Launch Platform in part via eight (8) Solid Rocket Booster (SRB) hold-down bolts. The bolts are fractured using redundant pyrotechnics, and are designed to drop through a hold-down post on the Mobile Launch Platform before the Space Shuttle begins movement. The Space Shuttle program has experienced numerous failures where a bolt has hung up. That is, it did not clear the hold-down post before liftoff and was caught by the SRBs. This places an additional structural load on the vehicle that was not included in the original certification requirements. The Space Shuttle is currently being certified to withstand the loads induced by up to three (3) of eight (8) SRB hold-down experiencing a "hang-up". The results of loads analyses performed for (4) stud hang-ups indicate that the internal vehicle loads exceed current structural certification limits at several locations. To determine the risk to the vehicle from four (4) stud hang-ups, the likelihood of the scenario occurring must first be evaluated. Prior to the analysis discussed in this paper, the likelihood of occurrence had been estimated assuming that the stud hang-ups were completely independent events. That is, it was assumed that no common causes or factors existed between the individual stud hang-up events. A review of the data associated with the hang-up events, showed that a common factor (timing skew) was present. This paper summarizes a revised likelihood evaluation performed for the four (4) stud hang-ups case considering that there are common factors associated with the stud hang-ups. The results show that explicitly (i.e. not using standard common cause methodologies such as beta factor or Multiple Greek Letter modeling) taking into account the common factor of timing skew results in an increase in the estimated likelihood of four (4) stud hang-ups of an order of magnitude over the independent failure case.

  5. Analysis and experimental studies of the control of hang gliders

    Phillips, W. H.


    A theoretical analysis of the longitudinal and lateral characteristics of hang gliders in straight flight, pullups, and turns is presented. Some examples of the characteristics of a straight-wing configuration and a Rogallo-wing configuration are given. A means for improving the control of hang gliders while retaining the same basic control feel is proposed.

  6. Investigation of wetting characteristics of liquid iron on dense MgAION-based ceramics by X-ray sessile drop technique

    Zhang, Z. T.; Matsushita, T.; Seetharaman, S.; Li, W. C.


    The wetting characteristics of liquid iron on dense MgAION-based composite ceramics were investigated using X-ray sessile drop technique. The contact angles were measured on substrates of different composites as functions of temperature and varying partial pressures of oxygen. The results with pure argon gas showed that contact angles kept almost constant in the temperature range 1823 to 1873 K. The contact angle was found to show a slight increase with increasing boron nitride (BN) content in MgAION-BN composites. These are attributed to the higher contact angle between BN substrate and liquid iron drop compared with that obtained for MgAION substrate. When the CO-CO2-Ar gas mixtures were introduced into the system, the contact angle showed an initial quick decrease followed by a slow decrease and then a period of nearly constant contact angle at a given temperature corresponding to the steady-state condition. Even in this case, BN seemed to cause an increase in the equilibrium contact angle. The equilibrium contact angle was found to decrease with increasing temperature. XRD results indicated that the substrate was oxidized and the oxidation products combined with FeO formed by the oxidation of the iron drop to from FeAl2O4 and Mg1-xFex) These were likely to form a ternary FeO-Al2O3-MgO slag or a quaternary slag by combining with B2O3. An interesting observation is that the iron drop moved away from the original site, probably due to the Marangoni effect.

  7. 'We Do Not Hang Around. It Is Forbidden' : Immigration and the Criminalisation of Youth Hanging around in the Netherlands

    T. Müller (Thaddeus)


    textabstractThe focus in this article is the ‘criminalisation’ of youth hanging around with the emergence of bans on hanging around. A critical social constructivist approach is used in this study, which draws predominantly on qualitative primary data collected between the late 1980s and 2010s. The

  8. The discovery and exploration of Hang Son Doong

    Limbert, H.; Limbert, D.; Hieu, N.; Phai, V. V.; Kinh Bac, D.; Phuong, T. H.; Granger, D.


    Hang Son Doong is located in the Phong Nha Ke Bang Limestone Massif in Quang Binh Province, Central Vietnam. Cave exploration by British cavers has been continuous in this area since 1990. Hang Son Doong is part of the Phong Nha Cave system which runs from the southern end of the National Park near the Lao border to the final resurgence at Phong Nha Cave. (Author)

  9. Sistem Informasi Akademik pada SMA Swasta Hang Tuah Belawan

    Syarifuddin, Ruisya


    Perancangan Sistem Informasi Akademik pada SMA Swasta Hang Tuah Belawan ini bertujuan untuk mempermudah proses pencarian atau searching data dan informasi untuk seluruh Siswa SMA Swasta Hang Tuah Belawan yang mengalami kesulitan dalam memperoleh data mengenai masalah Akademik tersebut. Faasilitas yang terdapat dalam aplikasi ini berupa penyediaan data dan informasi mengenai beritaberita terbaru, profil agenda kegiatan, dan data-data yang berguna untuk kelangsungan belajar si...

  10. J-R Curve Determination for Disk-shaped Compact Specimens Based on the Normalization Method and Direct Current Potential Drop Technique

    Chen, Xiang [ORNL; Nanstad, Randy K [ORNL; Sokolov, Mikhail A [ORNL


    Material ductile fracture toughness can be described by J-integral versus crack extension relationship (J-R curve). As a conventional J-R curve measurement method, unloading compliance (UC) becomes impractical in elevated temperature testing due to relaxation of the material and a friction induced back-up shape of the J-R curve. In addition, the UC method may underpredict the crack extension for standard disk-shaped compact (DC(T)) specimens. In order to address these issues, the normalization method and direct current potential drop (DCPD) technique were applied for determining J-R curves at 24 C and 500 C for 0.18T DC(T) specimens made from type 316L stainless steel. For comparison purchase, the UC method was also applied in 24 C tests. The normalization method was able to yield valid J-R curves in all tests. The J-R curves from the DCPD technique need adjustment to account for the potential drop induced by plastic deformation, crack blunting, etc. and after applying a newly-developed DCPD adjustment procedure, the post-adjusted DCPD J-R curves essentially matched J-R curves from the normalization method. In contrast, the UC method underpredicted the crack extension in all tests resulting in substantial deviation in the derived J-R curves manifested by high Jq values than the normalization or DCPD method. Only for tests where the UC method underpredicted the crack extension by a very small value, J-R curves determined by the UC method were similar to those determined by the normalization or DCPD method.

  11. The reduction of l-cystine in hydrochloric acid at mercury drop electrodes

    Ralph, T.R.; Hitchman, M.L.; Millington, J.P.; Walsh, F.C.


    The reduction of L-cystine in 0.1 mol dm3 HCl at 298 K has been studied at mercury electrodes. Dropping mercury electrode (DME), static mercury drop electrode (SMDE) and hanging mercury drop electrode (HMDE) modes were used with normal, sampled d.c. and differential pulse polarographic detection. The charge transfer kinetics for the irreversible reduction of L-cystine were complicated by reactant and product adsorption, by the formation of cysteinate complexes between mercury and the product ...

  12. Increase in Suicide Rates by Hanging in the Population of Tabasco, Mexico between 2003 and 2012

    Hernández-Alvarado, Mervyn Manuel; González-Castro, Thelma Beatriz; Tovilla-Zárate, Carlos Alfonso; Fresán, Ana; Juárez-Rojop, Isela E.; López-Narváez, María Lilia; Villar-Soto, Mario; Genis-Mendoza, Alma


    Background: Worldwide, the suicide rate is decreasing. To examine changes in the rates of completed suicide in the Mexican population from 2003 to 2012, we analyzed these changes according to: (i) the method of suicide; (ii) age group and (iii) gender. Methods: The data analyzed were obtained from governmental organizations from the State of Tabasco, Mexico. The data provided 1836 cases of subjects born and residing in Tabasco, who completed suicide in this state. Results: Suicide by hanging was a common choice of suicide method for Mexicans. The rate of suicide by hanging increased from 5.80 to 6.49 per 100,000 persons between 2003 and 2012, a rate percentage increase of 11.89%. Conclusions: Hanging was found to be the most common choice of suicide in the Mexican population, probably because the materials required are easily available and the method does not require complicated techniques, especially in the 55–64 age group. Strategies for prevention and intervention should be developed for the Mexican population considering suicide rates by age group and gender. PMID:27258292

  13. Increase in Suicide Rates by Hanging in the Population of Tabasco, Mexico between 2003 and 2012

    Mervyn Manuel Hernández-Alvarado


    Full Text Available Background: Worldwide, the suicide rate is decreasing. To examine changes in the rates of completed suicide in the Mexican population from 2003 to 2012, we analyzed these changes according to: (i the method of suicide; (ii age group and (iii gender. Methods: The data analyzed were obtained from governmental organizations from the State of Tabasco, Mexico. The data provided 1836 cases of subjects born and residing in Tabasco, who completed suicide in this state. Results: Suicide by hanging was a common choice of suicide method for Mexicans. The rate of suicide by hanging increased from 5.80 to 6.49 per 100,000 persons between 2003 and 2012, a rate percentage increase of 11.89%. Conclusions: Hanging was found to be the most common choice of suicide in the Mexican population, probably because the materials required are easily available and the method does not require complicated techniques, especially in the 55–64 age group. Strategies for prevention and intervention should be developed for the Mexican population considering suicide rates by age group and gender.

  14. Design of 3D printed insert for hanging culture of Caco-2 cells.

    Shen, Chong; Meng, Qin; Zhang, Guoliang


    A Caco-2 cell culture on Transwell, an alternative testing to animal or human testing used in evaluating drug intestinal permeability, incorrectly estimated the absorption of actively transported drugs due to the low expression of membrane transporters. Similarly, three-dimensional (3D) cultures of Caco-2 cells, which have been recommended to be more physiological relevant, were not superior to the Transwell culture in either accuracy or convenience in drug permeability testing. Using rapid 3D printing prototyping techniques, this study proposed a hanging culture of Caco-2 cells that performed with high accuracy in predicting drug permeability in humans. As found, hanging cultured Caco-2 cells formed a confluent monolayer and maintained high cell viability on the 3D printed insert. Compared with the normal culture on Transwell, the Caco-2 cells on the 3D printed insert presented ∼30-100% higher brush border enzyme activity and ∼2-7 folds higher activity of P-glycoprotein/multidrug resistance-associated protein 2 during 21 days of incubation. For the eight membrane transporter substrates, the predictive curve of the 3D printing culture exhibited better linearity (R(2) = 0.92) to the human oral adsorption than that of the Transwell culture (R(2) = 0.84), indicating better prediction by the 3D printing culture. In this regard, the 3D printed insert for hanging culture could be potentially developed as a convenient and low-cost tool for testing drug oral absorption.

  15. Numerical simulation of the effects of hanging sound absorbers on TABS cooling performance

    Rage, Nils; Kazanci, Ongun Berk; Olesen, Bjarne W.


    to a degradation of the room acoustic comfort. Therefore, challenges arise when this system has to be combined with acoustic requirements. Soffit-hanging sound absorbers embody a promising solution. This study focuses on quantifying their impact on the cooling performance of TABS, assessed by means of the cooling...... capacity coefficient of the ceiling deck. The influence of different ceiling coverage ratios (0-30-45-60 and 80%) as well as the influence of the distance at which the absorbers are placed is studied by numerical simulations using a new, specially-developed TRNSYS Type. Tests were performed in a test room...... simulating a two-person office of 20 m2, with a typical cooling load of 42 W/m2. The results show that covering 60% of the ceiling surface with sound absorbers hanging at 300 mm from the ceiling active deck is expected to reduce the cooling capacity coefficient of TABS by 15.8%. This drops to 25...

  16. Electrochemical studies of quinine in surfactant media using hanging mercury drop electrode: a cyclic voltammetric study.

    Dar, Riyaz Ahmad; Brahman, Pradeep Kumar; Tiwari, Sweety; Pitre, Krishna Sadashiv


    The electrochemical behavior of quinine was investigated by cyclic voltammetry (CV) and square wave voltammetry (SWV) using surfactant. The reduction peak current of quinine increases remarkably in presence of 1% CTAB. Its electrochemical behavior is quasi-reversible in the Britton-Robinson buffers of pH 10.38 by exhibiting the well-defined single cathodic and anodic waves and the ratio of I(p)(a)/I(p)(c) approaching one at the scan rate of 500 mVs(-1). On the basis of CV, SWV and Coulometry, electrochemical reduction mechanism of quinine has been proposed which has shown that protonation occurs on the nitrogen of the quinoline moiety. Linearity was obtained when the peak currents (I(p)) were plotted against concentrations of quinine in the range of 30.0-230.0 ng mL(-1) with a detection limit of 0.132 ng mL(-1) in SWV and 90.0-630.0 ng mL(-1) with a detection limit of 0.238 ng mL(-1) in DPV. Fast and sensitive SWV has been applied for the quantitative analysis of quinine in bark of Cinchona sp. and in soft drinks and a good recovery was obtained. The accuracy and precision of the method are determined and validated statistically. No interferences from other food additives were observed. The relative standard deviation for intraday and interday assay was 0.89 and 0.73% (n=3) respectively.

  17. Hanging-induced burst suppression pattern in EEG

    Nilgun Cinar


    Full Text Available Lethal suspension (hanging is one of the most common methods of attempting suicide. Spinal fractures, cognitive and motor deficits as well as epileptic seizures can be detected after unsuccessful hanging attempts. Introduced here is the case of a 25-year-old man exemplifying the clinical observations stated hereafter, who was conveyed to our emergency room after having survived attempted suicide by hanging, with his post-anoxic burst-suppression electroencephalography (BS-EEG pattern and clinical diagnoses in the post-comatose stage. The patient′s state of consciousness was gradually improved over a period of time. His neuropsychiatric assessment proved that memory deficit, a slight lack of attention and minor executive dysfunction was observed a month after the patient was discharged. Although the BS-EEG pattern indicates severe brain dysfunction, it is a poor prognostic factor; rarely, patients survive with minor cognitive deficits and can perform their normal daily activities.

  18. Pattern of burn injury in hang-glider pilots.

    Campbell, D C; Nano, T; Pegg, S P


    High-voltage electrical injury has been well documented in a number of situations, such as the occupational hazard of linesmen and construction workers, and in the context of overhead railway power lines. Two cases of hang-glider pilots contacting 11,000-volt power lines have recently been treated in the Royal Brisbane Hospital Burns Unit. They demonstrate an interesting pattern of injury, not described in current burns literature, involving both hand and lower abdominal burns. Both patients sustained full-thickness patches of burn injury, with underlying muscle damage and peripheral neurological injury. This distribution of injury seems to be closely related to the design of the hang glider.

  19. Dynamics of ultralight aircraft: Dive recovery of hang gliders

    Jones, R. T.


    Longitudinal control of a hang glider by weight shift is not always adequate for recovery from a vertical dive. According to Lanchester's phugoid theory, recovery from rest to horizontal flight ought to be possible within a distance equal to three times the height of fall needed to acquire level flight velocity. A hang glider, having a wing loading of 5 kg sq m and capable of developing a lift coefficient of 1.0, should recover to horizontal flight within a vertical distance of about 12 m. The minimum recovery distance can be closely approached if the glider is equipped with a small all-moveable tail surface having sufficient upward deflection.

  20. Christiaan Huygens and the Problem of the Hanging Chain

    Bukowski, John F.


    The seventeen-year-old Christiaan Huygens was the first to prove that a hanging chain did not take the form of the parabola, as was commonly thought in the early seventeenth century. We will examine Huygen's geometrical proof, and we will investigate the later history of the catenary.

  1. Christiaan Huygens and the Problem of the Hanging Chain

    Bukowski, John F.


    The seventeen-year-old Christiaan Huygens was the first to prove that a hanging chain did not take the form of the parabola, as was commonly thought in the early seventeenth century. We will examine Huygen's geometrical proof, and we will investigate the later history of the catenary.

  2. Weaning difficulty in a near hanging patient: An unusual cause

    Animesh Ray


    Full Text Available Suicidal hanging causes damage to the airways, neck blood vessels as well as soft tissue injuries. We report the development of tracheo-esophageal fistula in such a patient. Recurrent soiling of the airways and the resultant lung infection led to weaning failure. We highlight the approach to diagnosis and appropriate management in such a patient.

  3. Efficiency of hanging silt curtains in cross-flow

    Radermacher, M.; De Wit, L.; Uijttewaal, W.S.J.; Winterwerp, J.C.


    When dredging in sensitive environments, efforts have to be made to limit the free dispersal of suspended fine sediment from the dredging spill. Especially the use of hanging silt curtains as an environmental mitigation measure is widespread. Despite frequent application, their ability to reduce tur

  4. The epidemiology of injury in hang-gliding and paragliding.

    Rekand, Tiina


    Para- and hang-gliding are modern air sports that developed in the 20th century. Performers should possess technical skills and manage certified equipment for successful flight. Injuries may happen during the take-off, flight and landing. PubMed was searched using the search terms 'paragliding' and/or 'hang-gliding'. The reference lists of articles identified in the search strategy were also searched for relevant articles. The most common injuries are fractures, dislocations or sprains in the extremities, followed by spinal and head traumas. Multiple injuries after accidents are common. Collision with electrical wires may cause burn injuries. Fatal outcomes are caused by brain injuries, spinal cord injuries at the cervical level or aorta rupture. Accidents happen because of risk-taking behavior, lack of education or use of self-modified equipment. Observational studies have suggested the need for protection of the head, trunk and lower extremities. The measures proposed are often based on conclusions of observational studies and not proven through randomized studies. Better education along with focusing on possible risk factors will probably diminish the risks of hang- and paragliding. Large denominator-based case series, case-control and population-based studies are needed for assessment of the risks of hang- and paragliding.

  5. Proceedings of the Second International Colloquium on Drops and Bubbles

    Lecroissette, D. H. (Editor)


    Applications of bubble and drop technologies are discussed and include: low gravity manufacturing, containerless melts, microballoon fabrication, ink printers, laser fusion targets, generation of organic glass and metal shells, and space processing. The fluid dynamics of bubbles and drops were examined. Thermomigration, capillary flow, and interfacial tension are discussed. Techniques for drop control are presented and include drop size control and drop shape control.

  6. Hanging out with Which Friends? Friendship-Level Predictors of Unstructured and Unsupervised Socializing in Adolescence

    Siennick, Sonja E.; Osgood, D. Wayne


    Companions are central to explanations of the risky nature of unstructured and unsupervised socializing, yet we know little about whom adolescents are with when hanging out. We examine predictors of how often friendship dyads hang out via multilevel analyses of longitudinal friendship-level data on over 5,000 middle schoolers. Adolescents hang out…

  7. Preparation of Hollow SiC Ceramic Microspheres With Drop-tower Technique%炉内成球法制备SiC空心陶瓷微球

    李婧; 冯建鸿; 肖建建; 刘一杨; 李洁; 张占文; 李波


    采用干凝胶法,以聚碳硅烷(PCS )为原料,通过炉内成球技术制备了SiC空心陶瓷微球。并利用TG、IR、SEM、XRD等方法对陶瓷微球进行了成键结构、表面形貌等分析,讨论了有机聚合物的陶瓷化过程机理。结果表明,干凝胶成球技术能利用经纯化处理的聚碳硅烷在500~600℃下得到SiC空心陶瓷微球,采用乙醇作为发泡剂可使 PCS凝胶粒子得到良好发泡效果,提高载气中氦气含量至50%~80%可提高干凝胶粒子在吸热阶段的升温速率,微球经辐照后在850℃下碳化生成以β-SiC为主要相结构的球壳,球壳具有较好的表面平整度。%SiC ceramic microspheres were fabricated by drop-tower technique at low tem-perature using polycarbosilane (PCS ) as raw material . T he as-prepared microspheres were characterized by TG ,IR ,SEM and XRD .The reaction mechanism of organic poly-mer and the effects of process parameters (composition of furnace atmosphere and tem-perature) were investigated .The results show that ethanol as a blowing agent has a high blowing efficiency ,and the content of helium gas in the furnace atmosphere ranging rising to 50%-80% can increase the heating-up rate of gel particles in heat-absorbing stage .The high sphericity morphology is obtained at 500-600 ℃ .Moreover ,the SEM spectra indicate that irradiation can increase the surface finish quality and evenness of hollow SiC ceramic microspheres .

  8. Investigation of Flight Dynamic of Hang-glider

    B. Gáti


    Full Text Available This paper shows, how the most important parameters of a two-body system like a hang-glider, can be identified. The first step is to develop a simulation program with an acceptable reality model. Such a model involves a lot of constants. I carried out an investigation of sensitivity ir; order to select the constants that are the most important to specify. The results show that the aerodynamic constant cmq has the most significant effect on a  phygoidal oscillation. I have developed an identification program and a measuring system to determine the real value of this constant as well as the hang-glider's other aerodynamical and stability parameters.


    Rekha Gyanchand


    Full Text Available BACKGROUND Requirement of donor cornea is essential to target the corneal blind. The best method to procure such corneas is from any major hospitals, which has a mortuary facility. The eye donation with hanging as the cause of death is very common in a mortuary setup. Some factors that are concerning regarding corneas procured from death due to hanging is the prolonged exposure of the cornea at the time of death, the exact time of death is not known, most of the cadavers are refrigerated for investigations as these arrive at the mortuary usually at night. Due to these reasons, the corneal surgeons are hesitant to use corneas procured from death due to hanging for corneal transplantation. Analysing these corneas would contribute to a great extent to the donor cornea pool in providing sight to the corneal blind, especially as majority are young individuals who commit suicide by hanging. In this study, the donor corneas were analysed with regards to corneal epithelial defect, endothelial cell morphology and utilisation of these corneas for transplantation. The aim of the HCRP study is to analyse the effect of death due to hanging on donor cornea. 1. Corneal epithelial status. 2. Corneal endothelial cell morphology. 3. Utilisation of corneas for transplantation. MATERIALS AND METHODS Donor corneas from 22 donors who died due to hanging were procured from hospital mortuary. All the 44 corneas were transplanted. Various parameters like demography, death to enucleation time, cadaver preservation in cold storage, endothelial cell density and utilisation of cornea for transplantation were noted. Design- Retrospective study. Statistical Analysis- Descriptive statistics, Pearson and Spearman correlation and Chi-square test were used to test the hypotheses. RESULTS Out of the 44 corneas analysed, 75% of the donors were refrigerated as a part of medicolegal investigations protocol. The average DTP time was 12 hours in refrigerated group and 5 hours in non

  10. Interfacial Instabilities in Evaporating Drops

    Moffat, Ross; Sefiane, Khellil; Matar, Omar


    We study the effect of substrate thermal properties on the evaporation of sessile drops of various liquids. An infra-red imaging technique was used to record the interfacial temperature. This technique illustrates the non-uniformity in interfacial temperature distribution that characterises the evaporation process. Our results also demonstrate that the evaporation of methanol droplets is accompanied by the formation of wave-trains in the interfacial temperature field; similar patterns, however, were not observed in the case of water droplets. More complex patterns are observed for FC-72 refrigerant drops. The effect of substrate thermal conductivity on the structure of the complex pattern formation is also elucidated.

  11. Coalescence of a Drop inside another Drop

    Mugundhan, Vivek; Jian, Zhen; Yang, Fan; Li, Erqiang; Thoroddsen, Sigurdur


    Coalescence dynamics of a pendent drop sitting inside another drop, has been studied experimentally and in numerical simulations. Using an in-house fabricated composite micro-nozzle, a smaller salt-water drop is introduced inside a larger oil drop which is pendent in a tank containing the same liquid as the inner drop. On touching the surface of outer drop, the inner drop coalesces with the surrounding liquid forming a vortex ring, which grows in time to form a mushroom-like structure. The initial dynamics at the first bridge opening up is quantified using Particle Image Velocimetry (PIV), while matching the refractive index of the two liquids. The phenomenon is also numerically simulated using the open-source code Gerris. The problem is fully governed by two non-dimensional parameters: the Ohnesorge number and the diameter ratios of the two drops. The validated numerical model is used to better understand the dynamics of the phenomenon. In some cases a coalescence cascade is observed with liquid draining intermittently and the inner drop reducing in size.

  12. Masking and bondage in suicidal hanging: a case report.

    Benomran, F A; Masood, S E; Hassan, A I; Mohammad, A A


    The body of a 35-year-old man was found hanging in a relatively isolated place outdoors. A vest was wrapped over his head, neck and lower part of the face. The hands were loosely tied in front of the body. The vest was tucked between the neck and the ligature, to act as a pad. Thorough scene examination and post-mortem examination excluded any evidence of foul play. Although bondage is usually associated with autoerotic practices in asphyxiation deaths, it was established that this case was a suicide. DNA was used as a supportive measure to determine that the handkerchief and vest belonged to the deceased.

  13. Importance of tissue biopsy in suicidal hanging deaths

    Manal S. Bamousa


    The total number of cases was 62; 85.5% of the deceased were males, while 15% were females. The majority of cases (53% were among the age group of 20–30 years. Hemorrhage of the sternocleidomastoid muscle and carotid intimal tear were both found in 90% of cases. Thyroid congestion was detected in 91%, and Hashimoto’s thyroiditis was diagnosed in 2% of studied cases. The study discusses the importance of biopsy examination in hanging deaths and compares its results with other similar previous studies.

  14. Investigation of Flight Dynamic of Hang-glider

    B. Gáti


    This paper shows, how the most important parameters of a two-body system like a hang-glider, can be identified. The first step is to develop a simulation program with an acceptable reality model. Such a model involves a lot of constants. I carried out an investigation of sensitivity ir; order to select the constants that are the most important to specify. The results show that the aerodynamic constant cmq has the most significant effect on a  phygoidal oscillation. I have developed an identif...

  15. Genetic model of hanging wall syncline and central dome in extensional fault

    刘德来; 丁贵明; 鲁兵


    Hanging wall syncline and central dome are special extension structures, developing over the hanging wall in an extensional ramp-flat fault. Under the condition that the flat is sub-horizontal, the hanging wall syncline is separated from the half graben by the central dome. And on the dome forms an erosional surface. Both sediments in the half graben and erosional surface on the top of the central dome extended over the dome and entered into the hanging wall syncline with extension going on. Meanwhile, those having entered were overlapped by new sedimentary layers in the hanging wall syncline, so that there is a together-threaded, diachronic unconformity to form in the same epoch stratum. The layers in the hanging wall syncline also have an attribute of migrating laterally and getting tilted with extension. There is no sedimentation on the central dome. But sediments, which came from the half graben, got thicker over the dome in extension.

  16. Hanging Fatalities in Central Bangkok, Thailand: A 13-Year Retrospective Study

    Nattapong Tulapunt


    Full Text Available Hanging is violent asphyxial death. The objective of this study is to assess the data of hanging cases. A descriptive-retrospective study was conducted. We studied 244 hanging cases autopsied in Forensic Division, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand, between January 2001 and December 2013. The study included 197 men (80.7% and 47 women (19.2%. Their age ranged from 14 to 93 years. Most of these cases were incomplete hanging (83.6%. Features of hanging victims, such as tongue protrusion; congestion of face; petechial hemorrhage of face, conjunctiva, and internal organs; and neck injuries, significantly correlated with complete hanging. The predominant occupation of hanging victims was in the service industry (63.1%. Suicides usually occurred in private homes or apartments (84.8%. A suicide note was found in 6.1% of cases. The most common ligature material used was nylon rope, found in 61.1% of cases. The most underlying diseases of the victims in hanging cases were tuberculosis and human immunodeficiency virus infection, 9 cases each. Blood ethanol levels of 29 cases (11.8% were detected to be higher than 150 mg%. Methamphetamine and benzodiazepine were detected in 5.3% and 3.3% of cases, respectively. This study provides comprehensive baseline data of hanging cases in central Bangkok.

  17. Ligature material in hanging deaths: The neglected area in forensic examination

    Vipul Namdeorao Ambade


    Full Text Available The hanging mark is the most relevant feature of hanging and its characteristics are well known in the literature. Most of the time, the ligature material is not available during autopsy examination in hanging. Hence, the features of the ligature material are not submitted to systematic analysis. However, the type and position of the knot plays an important role in the mechanism of death and autopsy findings in hanging. Out of the total hanging deaths, complete hanging was seen in 67.7% of the cases, but a typical hanging was noted in only 10.2% of the cases. The commonest type of ligature material used for ligation around the neck was nylon rope followed by odhni and jute rope. The fixed knot was noted in 64.6% of the cases and a running (slip in 21.3% of the cases. The commonest position of the knot was at nape of the neck, followed by the left side of the neck at mastoid process. The number of turns/loops of a ligature around the neck was one turn in 72.4% and two in 25.2% the hanging deaths. Most victims committed suicide by hanging in their homes, and the commonest ligature points were trees, flowed by beams and ceiling hook/fans.

  18. Eye Drop Tips

    ... Involved News About Us Donate In This Section Eye Drop Tips en Español email Send this article ... the reach of children. Steps For Putting In Eye Drops: Start by tilting your head backward while ...

  19. Dilating Eye Drops

    ... Corneal Abrasions Dilating Eye Drops Lazy eye (defined) Pink eye (defined) Retinopathy of Prematurity Strabismus Stye (defined) Vision ... Corneal Abrasions Dilating Eye Drops Lazy eye (defined) Pink eye (defined) Retinopathy of Prematurity Strabismus Stye (defined) Vision ...

  20. Integrated optimisation technique based on computer-aided capacity and safety evaluation for managing downstream lane-drop merging area of signalised junctions

    Chen, CHAI; Yiik Diew, WONG


    This study provides an integrated strategy, encompassing microscopic simulation, safety assessment, and multi-attribute decision-making, to optimize traffic performance at downstream merging area of signalized intersections. A Fuzzy Cellular Automata (FCA) model is developed to replicate microscopic movement and merging behavior. Based on simulation experiment, the proposed FCA approach is able to provide capacity and safety evaluation of different traffic scenarios. The results are then evaluated through data envelopment analysis (DEA) and analytic hierarchy process (AHP). Optimized geometric layout and control strategies are then suggested for various traffic conditions. An optimal lane-drop distance that is dependent on traffic volume and speed limit can thus be established at the downstream merging area.

  1. Duodenoscope hang time does not correlate with risk of bacterial contamination.

    Heroux, Riley; Sheppard, Michelle; Wright, Sharon B; Sawhney, Mandeep; Hirsch, Elizabeth B; Kalaidjian, Robin; Snyder, Graham M


    Current professional guidelines recommend a maximum hang time for reprocessed duodenoscopes of 5-14 days. We sought to study the association between hang time and risk of duodenoscope contamination. We analyzed cultures of the elevator mechanism and working channel collected in a highly standardized fashion just before duodenoscope use. Hang time was calculated as the time from reprocessing to duodenoscope sampling. The relationship between hang time and duodenoscope contamination was estimated using a calculated correlation coefficient between hang time in days and degree of contamination on the elevator mechanism and working channel. The 18 study duodenoscopes were cultured 531 times, including 465 (87.6%) in the analysis dataset. Hang time ranged from 0.07-39.93 days, including 34 (7.3%) with hang time ≥7.00 days. Twelve cultures (2.6%) demonstrated elevator mechanism and/or working channel contamination. The correlation coefficients for hang time and degree of duodenoscope contamination were very small and not statistically significant (-0.0090 [P = .85] for elevator mechanism and -0.0002 [P = 1.00] for working channel). Odds ratios for hang time (dichotomized at ≥7.00 days) and elevator mechanism and/or working channel contamination were not significant. We did not find a significant association between hang time and risk of duodenoscope contamination. Future guidelines should consider a recommendation of no limit for hang time. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  2. Follow-up on hang gliding injuries in Colorado.

    Krissoff, W B


    In a period extending from July 1973 to December 1975, seven fatal hang glider accidents were recorded in Colorado, all among experienced pilots. In addition, 11 serious nonfatal injuries were reported, which may represent only a fraction of those occurring. Accidents were noted to be multifactorial, caused by (1) pilot error, (2) equipment failure, (3) terrain hazards, and (4) possible design shortcomings. Accidents can be expected to decline in frequency with improved pilot training programs, grading and regulation of sites, and standardized safety clothing. No doubt over time, the less safe standard Rogallo wing will be replaced by the more stable Superkites and controlled collapsibles, which offer a higher safety margin. In the last analysis, this sport will remain a popular yet high risk endeavor (Figs. 2 through 5).

  3. Characteristic Features of Hanging: A Study in Rural District of Central India.

    Ambade, Vipul Namdeorao; Kolpe, Dayanand; Tumram, Nilesh; Meshram, Satin; Pawar, Mohan; Kukde, Hemant


    The ligature mark is the most relevant feature of hanging. This study was undertaken with a view to determine the characteristic features of hanging and its association with ligature material or mode of suspension. Of a total medicolegal deaths reported at an Apex Medical Centre, hanging was noted in 4.1% cases, all suicidal with mortality rate of 1.5 per 100,000 population per year. The hanging was complete in 67.7% with nylon rope as the commonest type of ligature material used for ligation. The hanging mark was usually single, situated above thyroid cartilage, incomplete, prominent, and directed toward nape of neck. The mark of dribbling of saliva was seen in 11.8% cases. Facial congestion, petechial hemorrhage, and cyanosis were significantly seen in partial hanging. Though occasionally reported, the argent line was noted in 78.7% hanging deaths with neck muscle hemorrhage in 23.6% cases. Fracture of neck structure was predominant in complete hanging. © 2015 American Academy of Forensic Sciences.

  4. A psychological autopsy study of suicidal hanging from Cuttack, India: focus on stressful life situations.

    Bastia, Binaya K; Kar, Nilamadhab


    Factors and stressful life situations associated with suicidal hanging in a sample from India were studied with a view to explore preventability. Information was collected on consecutive suicidal hanging victims in a 2-year period from various sources including family members through psychological autopsy method. Out of 662 autopsies involving suicide during the study period, 104 had used hanging as the method. Age group of 21-30 years, married females, unmarried males, dowry related stress, unemployment, prolonged illness, failure in examinations, relationship and financial problems were associated more frequently with suicidal hanging. Stresses stemming from social practices and perceptions are linked with considerable number of suicidal hanging, which suggest priority areas for intervention.

  5. Non-Judicial Hanging in Guilan Province, Iran between 2011 and 2013

    Vahid Monsef Kasmaee


    Full Text Available Introduction: Hanging is one of the most commonly used way to commit suicide in many countries. This method used in suicide is considered a problem in Iran too, but no clear data exists regarding hanging in different regions or the country as a whole. Because of the epidemiologic differences in non-judicial hanging in different regions, this study aimed to assess it in Gilan province, Iran between 2011 and 2013. Methods: In this cross-sectional study, profiles of hanging cases registered in Poorsina hospital in Gilan, Iran between 2011 and 2013 were evaluated. Age, sex, marital status, place of residency, level of education, occupation, history of suicide, history of clinical illness, season of suicide and hanging outcome were evaluated. Results: 59 cases of hanging (mean age 31.4 ± 13.1 years and 83.0% male were evaluated. 12 (20.34% suffered from psychological disorders, and 9 (15.2% confessed to substance abuse. 7 (11.9% had a history of suicide attempts by hanging. Hanging was significantly higher in men (p<0.001, people with an education level of less than high school diploma (p=0.02 and the unemployed (p<0.05 patients. In the end, 20 (33.9% of these attempts resulted in death. Conclusion: The results of this study showed that in 2 years, 59 cases committed suicide by hanging themselves, 33.9% of which finally died. Committing suicide by hanging was significantly more prevalent in men, people with an education level of less than high school diploma and the unemployed.

  6. Retrospective Study of Postmortem Cases of ‘Hanging – A Method Of Suicide

    Mohammed Ziyauddin G Saiyed


    Full Text Available Introduction and Objective: Hanging is a form of violent asphyxial death. It produces painless death for the victims so that it is a widely accepted method of suicide. The rate of suicidal hanging cases is increasing day by day. The Objective of study is to find out demography of hanging, its distribution according to age group, sex, most common ligature material used by victim and observed post-mortem findings and in this way try to identify the causative factors and developing the preventive measures that are essential to reduce death due to hanging.Material and Methods: A retrospective study of hanging cases reported to mortuary of Vadilal Sarabhai General Hospital, Ahmedabad during a period of 2 years, (from November 2009 to October 2011 is carried out.Results: Out of total 2244 cases of post-mortem during 2 years, 74 (3.29% were hanging cases. Maximum cases 34 (45.94% of death due to hanging seen in age group 21-30 years. Majority of cases 46 (62.16% were observed in Males. Majority of victims have used Dupatta, 40 (54.05% as a ligature material. Manner of death is suicide in all cases. Cyanosis, salivary marks and petechial hemorrhage in brain observed in variable number of cases. Conclusion: Suicide by Hanging has become very common now a days. A well designed and comprehensive programme is needed to identify the causative factor and prevention of suicidal hanging. Appropriate education, reducing unemployment, improving the quality of self esteem and involvement of young generation in encouraging activities may reduce rate of death due to hanging

  7. Técnica da instilação de colírios em pacientes portadores de glaucoma crônico Eye drop instillation technique in chronic glaucoma patients

    Paulo Gelman Vaidergorn


    Full Text Available OBJETIVO: Verificar a técnica da instilação de colírio em pacientes portadores de glaucoma crônico. MÉTODOS: Estudo prospectivo realizado em 193 pacientes glaucomatosos. Para cada participante era entregue um frasco de colírio lubrificante (Dunason®, Laboratório Alcon, São Paulo, Brasil e solicitado que realizasse uma instilação. RESULTADOS: Os participantes utilizaram, em média, 1,64 ± 1,26 gotas de colírio por instilação e 54,5% dos pacientes fizeram contato do bico do colírio com a superfície ocular. Em 3,1% das instilações nenhuma gota de medicamento atingiu o olho, com o paciente não se dando conta do fato. A oclusão do ponto lacrimal ou a manutenção do olho fechado por dois minutos após a instilação não foi realizada em 87,0% dos participantes, e 61,6% piscaram repetidas vezes imediatamente após instilar a droga. CONCLUSÕES: Verificou-se que a maior parte dos participantes deste estudo efetuou a instilação do colírio de modo incorreto. Isto significa desperdiçar grande parte do conteúdo do frasco, aumentar as possibilidades de toxicidade sistêmica, não aproveitar a plenitude do efeito hipotensor das drogas e contaminar a extremidade do frasco de colírio. Portanto, o ensino da técnica adequada da instilação de colírio é absolutamente necessária para todos os pacientes.PURPOSE: To observe eye drop instillation technique in chronic glaucoma patients. METHODS: This is a prospective study enrolling 193 glaucomatous patients. Each received a sample of lubricant eye drop bottle (Dunason®, Alcon Laboratories, São Paulo, Brazil and was instructed to use it once. RESULTS: All patients used a mean amount of 1.64 ± 1.26 drops. In 54.5% of the patients, the eyedropper touched the eye and adnexa. In 3.1% the drops were not placed in the eye, without the patient being aware of this. In 87.0% of them, neither the lacrimal point occlusion nor the closure of the eyes for two minutes after instillation were

  8. “Waiting for the Bass to Drop”: Correlations between Intense Emotional Experiences and Production Techniques in Build-up and Drop Sections of Electronic Dance Music

    Ragnhild Torvanger Solberg


    Full Text Available This study investigates the correlations between theories of intense emotional experiences and production techniques used in the electronic dance music (EDM sections “build-up” and “drop”, which are designed to build tension and create a heightened emotional intensity among clubbers. This is done by descriptive and interpretive music analysis, where spectrograms and a schematic model visually represent the dominant production techniques. Through a theoretical framework consisting of musical expectancy and gravity, the analysis suggests that i extensive use of uplifters, ii the “drum roll effect”, iii large frequency changes, iv removal and reintroduction of bass and bass drum and v a contrasting “breakdown” cause tension and anticipation, which seems to correlate with a possible intensification of emotional experience. This is furthermore discussed and more broadly related to the club experience seen as a whole, drawing on the psychological concepts Peak experience, Strong experiences with music (SEM and Absorption.

  9. Turbulence, bubbles and drops

    Veen, van der Roeland Cornelis Adriaan


    In this thesis, several questions related to drop impact and Taylor-Couette turbulence are answered. The deformation of a drop just before impact can cause a bubble to be entrapped. For many applications, such as inkjet printing, it is crucial to control the size of this entrapped bubble. To study t

  10. Youth Crime Drop. Report.

    Butts, Jeffrey A.

    This report examines the recent drop in violent crime in the United States, discussing how much of the decrease seen between 1995-99 is attributable to juveniles (under age 18 years) and older youth (18-24 years). Analysis of current FBI arrest data indicates that not only did America's violent crime drop continue through 1999, but falling youth…

  11. Clinico-epidemiological study of near-hanging cases - An investigation from Nepal.

    Atreya, Alok; Kanchan, Tanuj


    Hanging is one of the commonest methods of suicide. Epidemiological data of near-hanging patients from Nepal is limited. The present research from Nepal attempts to review the clinico-epidemiological profile of near-hanging patients. A retrospective review of case records was done for the near hanging patients admitted to a tertiary care teaching hospital in Nepal, between August 2012 and August 2014. Details regarding socio-demographic profile, circumstances of hanging, clinical details, and outcome etc. were obtained and examined. During the study period, 10 near hanging patients were admitted to the hospital. The majority of the patients were below 30 years. Mean age of the study group was 28.8 years. The GCS on arrival ranged between 5/15 and 15/15 with the mean GCS being 9.5/15. Hypoxic encephalopathy and cerebral edema were the only noted complications. None of the patient had a cervical spinal injury. All the patients survived the near hanging episode. The mean ICU and hospital stay were 3.9 days and 6.2 days respectively. Prompt resuscitation, active interventions and intensive care support favors a good prognosis. Psychiatric evaluation and support to the patients and their relatives is the key to preventing such attempts in future.

  12. Unintentional strangulation by a cervical collar after attempted suicide by hanging.

    Lemyze, Malcolm; Palud, Aurore; Favory, Raphael; Mathieu, Daniel


    We report the case of a young man who attempted suicide by hanging and whose neurological status deteriorated until the cervical collar, that had been correctly placed by the prehospital team, was removed. We discuss the physiopathological mechanisms leading to death in hanging that is, a blockage of the blood stream to the brain leading to vasogenic and cytotoxic cerebral edema rather than asphyxia or spinal fracture. Our case supports the early removal of neck stabilization devices that can dangerously harm the patient after an attempted suicide by hanging, by increasing intracerebral pressure.

  13. How microstructures affect air film dynamics prior to drop impact

    Veen, van der R.C.A.; Hendrix, M.H.W.; Tran, A.T.; Sun, C.; Tsai, P.A.; Lohse, D.


    When a drop impacts a surface, a dimple can be formed due to the increased air pressure beneath the drop before it wets the surface. We employ a high-speed color interferometry technique to measure the evolution of the air layer profiles under millimeter-sized drops impacting hydrophobic micropatter

  14. Drop Tower Physics

    Dittrich, William A. Toby


    The drop towers of yesteryear were used to make lead shot for muskets, as described in The Physics Teacher1 in April 2012. However, modern drop towers are essentially elevators designed so that the cable can "break" on demand, creating an environment with microgravity for a short period of time, currently up to nine seconds at the drop tower in Bremen, Germany. Using these drop towers, one can briefly investigate various physical systems operating in this near zero-g environment. The resulting "Drop Tower Physics" is a new and exciting way to challenge students with a physical example that requires solid knowledge of many basic physics principles, and it forces them to practice the scientific method. The question is, "How would a simple toy, like a pendulum, behave when it is suddenly exposed to a zero-g environment?" The student must then postulate a particular behavior, test the hypothesis against physical principles, and if the hypothesis conforms to these chosen physical laws, the student can formulate a final conclusion. At that point having access to a drop tower is very convenient, in that the student can then experimentally test his or her conclusion. The purpose of this discussion is to explain the response of these physical systems ("toys") when the transition is made to a zero-g environment and to provide video demonstrations of this behavior to support in-class discussions of Drop Tower Physics.

  15. Application of experimental design and response surface technique for selecting the optimum RP-HPLC conditions for the determination of moxifloxacin HCl and ketorolac tromethamine in eye drops

    Pradipbhai D. Kalariya


    Full Text Available A method has been developed for the separation of moxifloxacin HCl and ketorolac tromethamine using reverse phase high-performance liquid chromatography (RP-HPLC on C18 column (250 × 4.6 mm, 5 μm with UV detection at 308 nm. Experimental designs were applied for multivariate optimization of the experimental conditions of RP-HPLC method. Three independent factors: methanol content in the mobile phase composition, buffer pH and flow rate were used to design mathematical models. Here faced central composite (FCC experimental design was used to study the response surface technique and to study in depth the effects of these independent factors. Derringer’s desirability function was applied to simultaneously optimize the retention time of last eluting peak (ketorolac tromethamine and tailing factor of moxifloxacin. The predicted optimum assay condition consisted of methanol and potassium dihydrogen phosphate buffer (pH 3.2; 25 mM, 0.5% Triethylamine in a proportion of 60:40% v/v, respectively, as the mobile phase at a flow rate of 1.2 mL min−1. Using this optimum condition, baseline separation of both drugs with good resolution and a run time of less than 7 min were achieved. The optimized assay condition was validated according to ICH guidelines to confirm specificity, linearity, accuracy and precision.

  16. On the role of hanging baffle performance enhancement by using slotted Helmholtz resonator array

    Hanina, R.; Yahya, I.; Harjana


    This paper emphasizes on the experimental investigation performance of hanging baffle with slotted Helmholtz resonator array inclusion. Laboratory test procedure refers to ATMS E-1050 was conducted for measuring the sound absorption coefficient of the Helmholtz resonator, while interrupted noise reverberation time measurement refers to ISO 3382-2 has been done for room acoustic performance test of the proposed design hanging baffle. The result shows that broadband absorption occurs when the Helmholtz resonator inserted to the hanging baffle. Sound energy dissipation increase both in resonance and viscous damping mechanism. It reduces the reverberation time significantly in all frequencies. The proposed design slotted resonator inclusion has brought opportunity for tuning the response and performance of the hanging baffle.

  17. An experimental study of the longitudinal aerodynamic and static stability characteristics of hang gliders

    Kilkenny, E. A.


    A mobile experimental test facility has been developed to carry out the aerodynamic evaluation of hang glider wings normally performed in a wind tunnel. Longitudinal aerodynamic data obtained using this facility is presented for three modern hang glider wings, a Silhouette, Demon 175 and Magic 166, together with surface flow patterns for the latter two wings. The longitudinal stability criterion are studied and alternatives established, equivalent to the stick fixed an...

  18. Does performance of hang power clean differentiate performance of jumping, sprinting, and changing of direction?

    Hori, Naruhiro; Newton, Robert U; Andrews, Warren A; Kawamori, Naoki; McGuigan, Michael R; Nosaka, Kazunori


    The primary purpose of this study was to investigate whether the athlete who has high performance in hang power clean, a common weightlifting exercise, has high performances in sprinting, jumping, and changing of direction (COD). As the secondary purpose, relationships between hang power clean performance, maximum strength, power and performance of jumping, sprinting, and COD also were investigated. Twenty-nine semiprofessional Australian Rules football players (age, height, and body mass [mean +/- SD]: 21.3 +/- 2.7 years, 1.8 +/- 0.1 m, and 83.6 +/- 8.2 kg) were tested for one repetition maximum (1RM) hang power clean, 1RM front squat, power output during countermovement jump with 40-kg barbell and without external load (CMJ), height of CMJ, 20-m sprint time, and 5-5 COD time. The subjects were divided into top and bottom half groups (n = 14 for each group) based on their 1RM hang power clean score relative to body mass, then measures from all other tests were compared with one-way analyses of variance. In addition, Pearson's product moment correlations between measurements were calculated among all subjects (n = 29). The top half group possessed higher maximum strength (P hang power clean, jumping, sprinting, COD, maximum strength, and power. Therefore, it seems likely there are underlying strength qualities that are common to the hang power clean, jumping, and sprinting.

  19. Rain Drop Charge Sensor

    S, Sreekanth T.

    begin{center} Large Large Rain Drop Charge Sensor Sreekanth T S*, Suby Symon*, G. Mohan Kumar (1) , S. Murali Das (2) *Atmospheric Sciences Division, Centre for Earth Science Studies, Thiruvananthapuram 695011 (1) D-330, Swathi Nagar, West Fort, Thiruvananthapuram 695023 (2) Kavyam, Manacaud, Thiruvananthapuram 695009 begin{center} ABSTRACT To study the inter-relations with precipitation electricity and precipitation microphysical parameters a rain drop charge sensor was designed and developed at CESS Electronics & Instrumentation Laboratory. Simultaneous measurement of electric charge and fall speed of rain drops could be done using this charge sensor. A cylindrical metal tube (sensor tube) of 30 cm length is placed inside another thick metal cover opened at top and bottom for electromagnetic shielding. Mouth of the sensor tube is exposed and bottom part is covered with metal net in the shielding cover. The instrument is designed in such a way that rain drops can pass only through unhindered inside the sensor tube. When electrically charged rain drops pass through the sensor tube, it is charged to the same magnitude of drop charge but with opposite polarity. The sensor tube is electrically connected the inverted input of a current to voltage converter operational amplifier using op-amp AD549. Since the sensor is electrically connected to the virtual ground of the op-amp, the charge flows to the ground and the generated current is converted to amplified voltage. This output voltage is recorded using a high frequency (1kHz) voltage recorder. From the recorded pulse, charge magnitude, polarity and fall speed of rain drop are calculated. From the fall speed drop diameter also can be calculated. The prototype is now under test running at CESS campus. As the magnitude of charge in rain drops is an indication of accumulated charge in clouds in lightning, this instrument has potential application in the field of risk and disaster management. By knowing the charge

  20. Mechanically tunable aspheric lenses via additive manufacture of hanging elastomeric droplets for microscopic applications

    Fuh, Yiin-Kuen; Chen, Pin-Wen; Lai, Zheng-Hong


    Mechanically deformable lenses with dynamically tunable focal lengths have been developed in this work. The fabricated five types of aspheric polydimethylsiloxane (PDMS) lenses presented here have an initial focal length of 7.0, 7.8, 9.0, 10.0 and 10.2 mm. Incorporating two modes of operation in biconvex and concave-convex configurations, the focal lengths can be tuned dynamically as 5.2-10.2, 5.5-9.9, 6.6-11.9, 6.1-13.5 and 6.6-13.5 mm respectively. Additive manufacturing was utilized to fabricate these five types of aspheric lenses (APLs) via sequential layering of PDMS materials. Complex structures with three-dimensional features and shorter focal lengths can be successfully produced by repeatedly depositing, inverting and curing controlled PDMS volume onto previously cured PDMS droplets. From our experiments, we empirically found a direct dependence of the focal length of the lenses with the amount (volume) of deposited PDMS droplets. This new mouldless, low-cost, and flexible lens fabrication method is able to transform an ordinary commercial smartphone camera into a low-cost portable microscope. A few microscopic features can be readily visualized, such as wrinkles of ladybird pupa and printed circuit board. The fabrication technique by successively applying hanging droplet and facile mechanical focal-length-tuning set-up can be easily adopted in the development of high-performance optical lenses.

  1. Experimental Investigation of Pendant and Sessile Drops in Microgravity

    Zhu, Zhi-Qiang; Brutin, David; Liu, Qiu-Sheng; Wang, Yang; Mourembles, Alexandre; Xie, Jing-Chang; Tadrist, Lounes


    The experiments regarding the contact angle behavior of pendant and sessile evaporating drops were carried out in microgravity environment. All the experiments were performed in the Drop Tower of Beijing, which could supply about 3.6 s of microgravity (free-fall) time. In the experiments, firstly, drops were injected to create before microgravity. The wettability at different surfaces, contact angles dependance on the surface temperature, contact angle variety in sessile and pendant drops were measured. Different influence of the surface temperature on the contact angle of the drops were found for different substrates. To verify the feasibility of drops creation in microgravity and obtain effective techniques for the forthcoming satellite experiments, we tried to inject liquid to create bigger drop as soon as the drop entering microgravity condition. The contact angle behaviors during injection in microgravity were also obtained.

  2. Simplified procedure for determining of drop and stilling basin

    Ali R. Vatankhah


    Full Text Available Drops are used to effectively dissipate the surplus energy of the water flow. A closed conduit drop conveys water and stills it at its downstream. I-type pipe drop is one kind of the closed conduit drops which is used in irrigation networks as a typical hydraulic structure. Sump elevation is an important design parameter for I-type pipe drop. Similarly, in supercritical flow structures, such as open channel chutes, determination of stilling basin invert elevation is very important. At present, these key design parameters are determined by the momentum and energy equations using tedious trial-and-error procedure. In this study, square conduit drop, pipe drop, and rectangular stilling basin are considered, and three explicit equations have been developed by (multiple nonlinear regression technique to determine the sump and stilling basin invert elevations. Being very simple and accurate, these equations can be easily used to design the closed conduit drops and stilling basins by hydraulic engineers.

  3. The Vibration of an Inviscid Incompressible Sessile Drop

    Smith, Marc


    The fundamental frequencies and normal modes of vibration of a sessile drop supported on a horizontal planar surface are found using an integrated analytical and numerical technique. Spherical coordinates are used to describe the interface shape, but the potential flow field inside the drop is computed numerically using the finite element method. The numerical velocity potentials at the interface for both the fluid inside the drop and outside are fitted using a Legendre series. When these series are combined in the interfacial normal-stress balance the result is a linear eigenvalue problem that is solved numerically. Results will be presented for sessile drops with different contact angles without gravity and compared to experimental data. This technique can also be extended to sessile drops with gravity, in which the drop shape is flattened, and to substrate geometries that are not planar, such as a drop in a shallow cavity or hole.

  4. Lambda-dropping

    Danvy, Olivier; Schultz, Ulrik Pagh


    ;rbæk's case study presented at PEPM '95, most polyvariant specializers for procedural programs operate on recursive equations. To this end, in a pre-processing phase, they lambda-lift source programs into recursive equations, As a result, residual programs are also expressed as recursive equations, often......Lambda-lifting a functional program transforms it into a set of recursive equations. We present the symmetric transformation: lambda-dropping. Lambda-dropping a set of recursive equations restores block structure and lexical scope.For lack of scope, recursive equations must carry around all...... with dozens of parameters, which most compilers do not handle efficiently. Lambda-dropping in a post-processing phase restores their block structure and lexical scope thereby significantly reducing both the compile time and the run time of residual programs....

  5. Impact of granular drops

    Marston, J. O.


    We investigate the spreading and splashing of granular drops during impact with a solid target. The granular drops are formed from roughly spherical balls of sand mixed with water, which is used as a binder to hold the ball together during free-fall. We measure the instantaneous spread diameter for different impact speeds and find that the normalized spread diameter d/D grows as (tV/D)1/2. The speeds of the grains ejected during the “splash” are measured and they rarely exceed twice that of the impact speed.

  6. Coalescence of sessile drops

    Nikolayev, Vadim; Pomeau, Yves; Andrieu, Claire


    We present an experimental and theoretical description of the kinetics of coalescence of two water drops on a plane solid surface. The case of partial wetting is considered. The drops are in an atmosphere of nitrogen saturated with water where they grow by condensation and eventually touch each other and coalesce. A new convex composite drop is rapidly formed that then exponentially and slowly relaxes to an equilibrium hemispherical cap. The characteristic relaxation time is proportional to the drop radius R * at final equilibrium. This relaxation time appears to be nearly 10 7 times larger than the bulk capillary relaxation time t b = R * $\\eta$/$\\sigma$, where $\\sigma$ is the gas--liquid surface tension and $\\eta$ is the liquid shear viscosity. In order to explain this extremely large relaxation time, we consider a model that involves an Arrhenius kinetic factor resulting from a liquid--vapour phase change in the vicinity of the contact line. The model results in a large relaxation time of order t b exp(L/R...

  7. Sessile drops in microgravity

    Sparavigna, Amelia Carolina


    Interfaces with a liquid are governing several phenomena. For instance, these interfaces are giving the shape of sessile droplets and rule the spread of liquids on surfaces. Here we analyze the shape of sessile axisymmetric drops and how it is depending on the gravity, obtaining results in agreement with experimental observations under conditions of microgravity.



    This paper introduces a new concept of the de-sign of the two storey intake in rivers with deficient discharge,gravel bed and higher diversion ratio. Instead of using classi-cal types of intake, a kind of two-level hanged-plate intake de-signs was suggested. The hanged-plate was arranged in themiddle level depth of flow and flow was separated to two por-tions I. E. The region above the hanged-plate and the regionunder the hanged-plate. In such way, the upper stream flowsinto channel and the bottom stream becomes the pressureflow. By using this arrangement, clearer water including lesssediment are deflected into irrigation channel in addition to in-creasing the transport sediment ratio. In this paper, flow pat-terns, velocity profile, pressure distribution, and diversionratio were studied experimentally for two different headers ofhanged-plate, P-weir and L-weir. The main characteristics offlow through hanged-plate was also inverstigated and com-pared with each other. The design works better in comparisonwith artificial band, sluice dam intake work, and so on.

  9. Suicidal hanging in Kuwait: retrospective analysis of cases from 2010 to 2012.

    Abd-Elwahab Hassan, Dalia; Ghaleb, Sherein S; Kotb, Heba; Agamy, Mervat; Kharoshah, Magdy


    Suicide is an important health hazard worldwide. We retrospectively analyzed the autopsy records of the Institute of Forensic Medicine between 2010 and 2012 to document the characteristics of fatalities resulting from hanging in Kuwait. Upon analysis of death scene investigation and autopsy reports together with the information gathered from the police, the cases of hanging fatalities of suicidal origin were selected. A retrospective study was carried out on 118 suicidal hanging cases autopsied at Forensic Medicine Center in Kuwait (from 2010 to 2012). Of these cases, 86 (73%) were males and 32 females (27%). There was an increasing trend of hanging among ages between 21 and 50 years (87.3%) and the third decade had the highest number of victims (about 43%) between all age groups. Local Kuwaiti nationals comprised a small proportion of cases (7 persons, 5.9%), while the others were foreigners working in Kuwait with an Indian precedence (54 persons, 54.8%), followed by other 12 different nationalities representing 39.3% of the cases. In conclusion, there was a decreasing trend of suicide by hanging in Kuwait from 44 cases in 2010 to 25 cases in 2012.

  10. Liver mobilization and liver hanging for totally laparoscopic right hepatectomy: an easy way to do it.

    Rotellar, Fernando; Pardo, Fernando; Martí-Cruchaga, Pablo; Zozaya, Gabriel; Valentí, Victor; Bellver, Manuel; Lopez-Olaondo, Luis; Hidalgo, Francisco


    The purpose of this study is to describe a technical modification that facilitates right liver mobilization in laparoscopic right hepatectomy (LRH). In the supine position, an inflatable device is placed under the patient's right chest. For right hemiliver mobilization, the table is placed in 30° anti-Trendelenburg and full-left tilt. Balloon inflation offers an additional 30° left inclination that places the patient in an almost left lateral position. Foot and lateral supports are placed to prevent patient slippage during changes in the patient positioning. From December 2013 to October 2015, this technique has been used in 10 consecutive LRH. The indications for these procedures were as follows: four donor hepatectomies for living donor liver transplant, three hepatocellular carcinomas and one peripheral cholangiocarcinoma in cirrhotic patients, one hepatocellular carcinoma in a non-cirrhotic patient, and one case of colorectal cancer metastases. In this period, it has also been used to facilitate mobilization and resection in the posterior segments of the liver in seven patients. In every case, right hemiliver mobilization was easily performed in a maximum time of 15 min and placement of a tape or plastic tube for liver hanging was prepared. We have not observed any complication directly attributable to the technique herein described (i.e. right brachialgia; arms, back or left flank pain) in the early or late postoperative follow-up. The additional left inclination obtained with the inflation of a balloon under the right chest facilitates right hemiliver mobilization. Its use may help in the performance and adoption of LRH.

  11. Self-similar vortex-induced vibrations of a hanging string

    Grouthier, Clement; Modarres-Sadeghi, Yahya; de Langre, Emmanuel


    An experimental analysis of the vortex-induced vibrations of a hanging string with variable tension along its length is presented in this paper. It is shown that standing waves develop along the hanging string. The evolution of the Strouhal number St with the Reynolds number Re first follows a trend similar to what is observed for a circular cylinder in a flow for relatively low Reynolds numbers (32hanging string is then explained theoretically by performing a linear stability analysis of an adapted wake-oscillator model. This linear stability analysis finally provides an accurate description of the mode shapes and of the evolution of the self-similarity coefficient with the flow speed.

  12. [History and Technique of Epidural Anaesthesia].

    Waurick, Katrin; Waurick, René


    In 1901, the first Epidural anesthesia via a caudal approach was independently described by two FrenchmanJean-Anthanase Sicard and Fernand Cathelin.. The Spanish military surgeon, Fidel Pagés Miravé, completed the lumbar approach successfully in 1921. The two possibilities for identification of the epidural space the "loss of resistance" technique and the technique of the "hanging drop" were developed by Achille Mario Dogliotti, an Italian, and Alberto Gutierrez, an Argentinean physician, at the same time. In 1956 John J. Bonica published the paramedian approach to the epidural space. As early as 1931 Eugene Aburel, a Romanian obstetrician, injected local anaesthetics via a silk catheter to perform lumbar obstetric Epidural analgesia. In 1949 the first successful continuous lumbar Epidural anaesthesia was reported by Manuel Martinez Curbelo, a Cuban. Epidural anaesthesia can be performed in sitting or lateral position in all segments of the spinal column via the median or paramedian approach. Different off-axis angles pose the challenge in learning the technique.


    C.Carstensen; Jun Hu


    A unified a posteriori error analysis has been developed in [18,21-23] to analyze the finite element error a posteriori under a universal roof.This paper contributes to the finite element meshes with hanging nodes which are required for local mesh-refining.The twodimensional 1-irregular triangulations into triangles and parallelograms and their combinations are considered with conforming and nonconforming finite element methods named after or by Courant,Q1,Crouzeix-Raviart,Han,Rannacher-Turek,and others for the a posteriori error analysis for triangulations with hanging nodes of degree≤1 which are fundamental for local mesh refinement in self-adaptive finite element discretisations.

  14. Coalescence of Liquid Drops

    Eggers, J; Stone, H A; Eggers, Jens; Lister, John R.; Stone, Howard A.


    When two drops of radius $R$ touch, surface tension drives an initially singular motion which joins them into a bigger drop with smaller surface area. This motion is always viscously dominated at early times. We focus on the early-time behavior of the radius $\\rmn$ of the small bridge between the two drops. The flow is driven by a highly curved meniscus of length $2\\pi \\rmn$ and width $\\Delta\\ll\\rmn$ around the bridge, from which we conclude that the leading-order problem is asymptotically equivalent to its two-dimensional counterpart. An exact two-dimensional solution for the case of inviscid surroundings [Hopper, J. Fluid Mech. ${\\bf 213}$, 349 (1990)] shows that R)]$; and thus the same is true in three dimensions. The case of coalescence with an external viscous fluid is also studied in detail both analytically and numerically. A significantly different structure is found in which the outer fluid forms a toroidal bubble of radius $\\Delta \\propto \\rmn^{3/2}$ at the meniscus and $\\rmn \\sim (t\\gamma/4\\pi\\eta)...

  15. Drop Testing Representative Multi-Canister Overpacks

    Snow, Spencer D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Morton, Dana K. [Idaho National Lab. (INL), Idaho Falls, ID (United States)


    The objective of the work reported herein was to determine the ability of the Multi- Canister Overpack (MCO) canister design to maintain its containment boundary after an accidental drop event. Two test MCO canisters were assembled at Hanford, prepared for testing at the Idaho National Engineering and Environmental Laboratory (INEEL), drop tested at Sandia National Laboratories, and evaluated back at the INEEL. In addition to the actual testing efforts, finite element plastic analysis techniques were used to make both pre-test and post-test predictions of the test MCOs structural deformations. The completed effort has demonstrated that the canister design is capable of maintaining a 50 psig pressure boundary after drop testing. Based on helium leak testing methods, one test MCO was determined to have a leakage rate not greater than 1x10-5 std cc/sec (prior internal helium presence prevented a more rigorous test) and the remaining test MCO had a measured leakage rate less than 1x10-7 std cc/sec (i.e., a leaktight containment) after the drop test. The effort has also demonstrated the capability of finite element methods using plastic analysis techniques to accurately predict the structural deformations of canisters subjected to an accidental drop event.

  16. Behavior of liquid drop situated between two oscillating planes

    Korenchenko, A E [Institute of Metallurgy, Russian Academy of Science, Ural Branch, 101 Amundsen str., Ekaterinburg 620219 (Russian Federation); Beskachko, V P [South Ural State University, 76 Lenin str., Chelyabinsk 454080 (Russian Federation)], E-mail:


    The levitation drop technique is widely used for the measurement of the surface tension and viscosity of liquids. An experiment with a drop situated between two horizontal rigid planes gives the same possibilities. The dynamic problem is solved numerically in the following cases: (1) the free oscillations of the drop when the plates are motionless; (2) the forced oscillations when the upper plate makes a translational vibration in the normal direction. The possibility of viscosity determination in such experiments is shown.

  17. Characterization of biofluids prepared by sessile drop formation.

    Esmonde-White, Karen A; Esmonde-White, Francis W L; Morris, Michael D; Roessler, Blake J


    Sessile drop formation, also called drop deposition, has been studied as a potential medical diagnostic, but the effects of complex biofluid rheology on the final deposition pattern are not well understood. We studied two model biofluids, blood plasma and synovial fluid, when deposited onto slightly hydrophilic substrates forming a contact angle of 50-90°. Drops were imaged during the evaporation process and geometric properties of the drop, such as contact angle and drop height, were calculated from the images. The resulting dried biofluid drops were then examined using light microscopy and Raman spectroscopy to assess morphological and chemical composition of the dried drop. The effect of substrate contact angle (surface wetting) and fluid concentration was examined. We found that when biofluids are deposited onto slightly hydrophilic surfaces, with a contact angle of 50-90°, a ring-shaped deposit was formed. Analysis of the drying drop's geometric properties indicates that biofluid dynamics follow the piling model of drop formation, as proposed by Deegan et al. The final deposition pattern varied with substrate surface and concentration, as shown by light microscopy photos of dried drops. The chemical composition of the outer ring was minimally affected by substrate surface, but the spatial heterogeneity of protein distribution within the ring varied with concentration. These results indicate that biofluid drop deposition produces ring-shaped deposits which can be examined by multiple analytical techniques.

  18. Hydrodynamics of evaporating sessile drops

    Barash, L Yu


    Several dynamical stages of the Marangoni convection of an evaporating sessile drop are obtained. We jointly take into account the hydrodynamics of an evaporating sessile drop, effects of the thermal conduction in the drop and the diffusion of vapor in air. The stages are characterized by different number of vortices in the drop and the spatial location of vortices. During the early stage the array of vortices arises near a surface of the drop and induces a non-monotonic spatial distribution of the temperature over the drop surface. The number of near-surface vortices in the drop is controlled by the Marangoni cell size, which is calculated similar to that given by Pearson for flat fluid layers. The number of vortices quickly decreases with time, resulting in three bulk vortices in the intermediate stage. The vortex structure finally evolves into the single convection vortex in the drop, existing during about 1/2 of the evaporation time.

  19. Leidenfrost Drop on a Step

    Lagubeau, Guillaume; Le Merrer, Marie; Clanet, Christophe; Quere, David


    When deposited on a hot plate, a water droplet evaporates quickly. However, a vapor film appears under the drop above a critical temperature, called Leidenfrost temperature, which insulates the drop from its substrate. Linke & al (2006) reported a spontaneous movement of such a drop, when deposited on a ratchet. We study here the case of a flat substrate decorated with a single micrometric step. The drop is deposited on the lower part of the plate and pushed towards the step at small constant velocity. If the kinetic energy of the drop is sufficient, it can climb up the step. In that case, depending on the substrate temperature, the drop can either be decelerated or accelerated by the step. We try to understand the dynamics of these drops, especially the regime where they accelerate. Taking advantage of this phenomenon, we could then build a multiple-step setup, making it possible for a Leidenfrost drop to climb stairs.

  20. 75 FR 73074 - Duke Energy Hanging Rock II, LLC; Supplemental Notice That Initial Market-Based Rate Filing...


    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Duke Energy Hanging Rock II, LLC; Supplemental Notice That Initial Market... supplemental notice in the above-referenced proceeding, of Duke Energy Hanging Rock II, LLC's application...

  1. Low-Bond Axisymmetric Drop Shape Analysis for Surface Tension and Contact Angle Measurements of Sessile Drops

    Stalder, A.F.; Melchior, T.; Müller, M.; Sage, D; T. Blu; Unser, M


    A new method based on the Young-Laplace equation for measuring contact angles and surface tensions is presented. In this approach, a first-order perturbation technique helps to analytically solve the Young-Laplace equation according to photographic images of axisymmetric sessile drops. When appropriate, the calculated drop contour is extended by mirror symmetry so that reflection of the drop into substrate allows the detection of position of the contact points. To keep a wide range of applica...

  2. Improvement of hang glider performance by use of ultralight elastic wing

    Wolf, J. S.


    The problem of the lateral controllability of the hang glider by the pilot's weight shift was considered. The influence of the span and the torsional elasticity of the wing was determined. It was stated that an ultralight elastic wing of a new kind was most suitable for good control. The wing also has other advantageous properties.

  3. Measurement of the Mass of an Object Hanging from a Spring--Revisited

    Serafin, Kamil; Oracz, Joanna; Grzybowski, Marcin; Koperski, Maciej; Sznajder, Pawel; Zinkiewicz, Lukasz; Wasylczyk, Piotr


    In an open competition, students were to determine the mass of a metal cylinder hanging on a spring inside a transparent enclosure. With the time for experiments limited to 24 h due to the unexpectedly large number of participants, a few surprisingly accurate results were submitted, the best of them differing by no more than 0.5% from the true…

  4. Accidental hanging: a novel mobile suspension apparatus partially hidden inside the clothes.

    Kodikara, Sarathchandra


    Accidental hanging is uncommon. An immobile/fixed and exposed suspension apparatus is seen in almost all cases of hanging. A 50-year-old man, who was drunk, was trying to steal an iron rod by hiding it under his clothing. To secure hiding, he attached it to his body by a loose ligature around the neck, the waist belt of the sarong, and another band around the waist and by his underwear. Sometime later, because of ethanol intoxication, he fell asleep in the sitting position. While he was sitting on the floor, the iron rod was lifted up accidentally, and its upper end was wedged against the wall behind the victim, and the lower end was fixed against the floor. When he fell asleep, the weight of the tilted head acted as the constricting force compressing the neck by the ligature that was used to attach the iron rod to the neck. The cause of death was concluded as hanging in a man with ethanol intoxication. This case highlights a novel mobile suspension apparatus partially hidden inside the clothes, in a case of accidental hanging. A similar case has not been reported in the forensic literature.


    Yanki D.


    Full Text Available ABSTRACT: In Sikkim, the rate of suicide has been on the rise since the last 10 years. Suicidal hanging as method of ending life is a major concern among school children. It is very rare that the victims are brought on time for successful resuscit ation in Sikkim. Suicide by hanging is probably the most easy way to go about taking one’s own life , as the means to do it are easily available and uncomplicated and, brutally efficient in most case s . This is a case report of a young female who was brought to the emergency room of our hospital a s a case of suicidal hanging. On admission her GCS was 6; she was unconscious with deteriorating v ital parameters and the breathing was laboured with SpO2 of 40% in room air. Early interv ention with intubation with ventilatory and circulatory support was given and she walked home a fter 7 days without any neurological deficit. KEY WORDS: Near hanging suicide, early intervention

  6. Superheated drop neutron spectrometer

    Das, M; Roy, B; Roy, S C; Das, Mala


    Superheated drops are known to detect neutrons through the nucleation caused by the recoil nuclei produced by the interactions of neutrons with the atoms constituting the superheated liquid molecule. A novel method of finding the neutron energy from the temperature dependence response of SDD has been developed. From the equivalence between the dependence of threshold energy for nucleation on temperature of SDD and the dependence of dE/dx of the recoil ions with the energy of the neutron, a new method of finding the neutron energy spectrum of a polychromatic as well as monochromatic neutron source has been developed.

  7. Assessment of the relative error in sessile drop method automation task

    Levitskaya T.О.


    Assessment of the relative error in the sessile drop method automation. Further development of the sessile drop method is directly related to the development of new techniques and specially developed algorithms enabling automatic computer calculation of surface properties. The sessile drop method mathematical apparatus improvement, drop circuit equation transformation to a form suitable for working, the drop surface calculation method automation, analysis of relative errors in the calculation...

  8. Settling of copper drops in molten slags

    Warczok, A.; Utigard, T. A.


    The settling of suspended metal and sulfide droplets in liquid metallurgical, slags can be affected by electric fields. The migration of droplets due to electrocapillary motion phenomena may be used to enhance the recovery of suspended matte/metal droplets and thereby to increase the recovery of pay metals. An experimental technique was developed for the purpose of measuring the effect of electric fields on the settling rate of metallic drops in liquid slags. Copper drops suspended in CaO-SiO2-Al2O3-Cu2O slags were found to migrate toward the cathode. Electric fields can increase the settling rate of 5-mm-diameter copper drops 3 times or decrease the settling until levitation by reversal of the electric field. The enhanced settling due to electric fields decreases with increasing Cu2O contents in the slag.

  9. Square wave voltammetry at the dropping mercury electrode: Theory

    Christie, J.H.; Turner, J.A.; Osteryoung, R.A.


    The theoretical aspects of square wave voltammetry at the dropping mercury electrode are presented. The technique involves scanning the entire potential range of interest on a single drop of a DME. Asymmetries in the waveform as well as variations in current measurement parameters are discussed. Indications are that previous uses of the waveform may not have utilized all its capabilities.

  10. Drops with non-circular footprints

    Ravazzoli, Pablo D; Diez, Javier A


    In this paper we study the morphology of drops formed on partially wetting substrates, whose footprint is not circular. This type of drops is a consequence of the breakup processes occurring in thin films when anisotropic contact line motions take place. The anisotropy is basically due to hysteresis effects of the contact angle since some parts of the contact line are wetting, while others are dewetting. Here, we obtain a peculiar drop shape from the rupture of a long liquid filament sitting on a solid substrate, and analyze its shape and contact angles by means of goniometric and refractive techniques. We also find a non--trivial steady state solution for the drop shape within the long wave approximation (lubrication theory), and compare most of its features with experimental data. This solution is presented both in Cartesian and polar coordinates, whose constants must be determined by a certain group of measured parameters. Besides, we obtain the dynamics of the drop generation from numerical simulations of...

  11. Drops with non-circular footprints

    Ravazzoli, Pablo D.; González, Alejandro G.; Diez, Javier A.


    In this paper we study the morphology of drops formed on partially wetting substrates, whose footprint is not circular. These drops are consequence of the breakup processes occurring in thin films when anisotropic contact line motions take place. The anisotropy is basically due to the hysteresis of the contact angle since there is a wetting process in some parts of the contact line, while a dewetting occurs in other parts. Here, we obtain a characteristic drop shape from the rupture of a long liquid filament sitting on a solid substrate. We analyze its shape and contact angles by means of goniometric and refractive techniques. We also find a non-trivial steady state solution for the drop shape within the long wave approximation (lubrication theory), and we compare most of its features with experimental data. This solution is presented both in Cartesian and polar coordinates, whose constants must be determined by a certain group of measured parameters. Besides, we obtain the dynamics of the drop generation from numerical simulations of the full Navier-Stokes equation, where we emulate the hysteretic effects with an appropriate spatial distribution of the static contact angle over the substrate.

  12. Bubble and Drop Nonlinear Dynamics (BDND)

    Trinh, E. H.; Leal, L. Gary; Thomas, D. A.; Crouch, R. K.


    Free drops and bubbles are weakly nonlinear mechanical systems that are relatively simple to characterize experimentally in 1-G as well as in microgravity. The understanding of the details of their motion contributes to the fundamental study of nonlinear phenomena and to the measurement of the thermophysical properties of freely levitated melts. The goal of this Glovebox-based experimental investigation is the low-gravity assessment of the capabilities of a modular apparatus based on ultrasonic resonators and on the pseudo- extinction optical method. The required experimental task is the accurate measurements of the large-amplitude dynamics of free drops and bubbles in the absence of large biasing influences such as gravity and levitation fields. A single-axis levitator used for the positioning of drops in air, and an ultrasonic water-filled resonator for the trapping of air bubbles have been evaluated in low-gravity and in 1-G. The basic feasibility of drop positioning and shape oscillations measurements has been verified by using a laptop-interfaced automated data acquisition and the optical extinction technique. The major purpose of the investigation was to identify the salient technical issues associated with the development of a full-scale Microgravity experiment on single drop and bubble dynamics.

  13. Interaction of two deformable viscous drops under external temperature gradient

    Berejnov, V V; Nir, A


    The axisymmetric deformation and motion of interacting droplets in an imposed temperature gradient is considered using boundary-integral techniques for slow viscous motion. Results showing temporal drop motion, deformations and separation are presented for equal-viscosity fluids. The focus is on cases when the drops are of equal radii or when the smaller drop trails behind the larger drop. For equal-size drops, our analysis shows that the motion of a leading drop is retarded while the motion of the trailing one is enchanced compared to the undeformable case. The distance between the centers of equal-sized deformable drops decreases with time. When a small drop follows a large one, two patterns of behavior may exist. For moderate or large initial separation the drops separate. However, if the initial separation is small there is a transient period in which the separation distance initially decreases and only afterwards the drops separate. This behavior stems from the multiple time scales that exist in the syst...

  14. Drop motion due to oscillations of an inclined substrate

    Xia, Yi; Chang, Chun-Ti; Daniel, Susan; Steen, Paul


    A sessile drop on a stationary inclined substrate remains pinned unless the angle of inclination is greater than some critical value. Alternatively, when shaken at even small angles of inclination, the drop undergoes shape deflections which may lead to drop translation. Translation occurs when large contact angle fluctuations, favored by oscillations at resonance, overcome contact angle hysteresis. In this study, resonance is triggered by substrate-normal oscillations. The drop translation is typically observed to be of constant speed for a given set of parameters. The speed is measured experimentally as a function of resonance mode, driving amplitude and drop volume. This technique of activating the motion of drops having a particular volume can be utilized for applications of droplet selection and transport.

  15. Microwave Dielectric Heating of Drops in Microfluidic Devices

    Issadore, David; Brown, Keith A; Sandberg, Lori; Weitz, David; Westervelt, Robert M


    We present a technique to locally and rapidly heat water drops in microfluidic devices with microwave dielectric heating. Water absorbs microwave power more efficiently than polymers, glass, and oils due to its permanent molecular dipole moment that has a large dielectric loss at GHz frequencies. The relevant heat capacity of the system is a single thermally isolated picoliter drop of water and this enables very fast thermal cycling. We demonstrate microwave dielectric heating in a microfluidic device that integrates a flow-focusing drop maker, drop splitters, and metal electrodes to locally deliver microwave power from an inexpensive, commercially available 3.0 GHz source and amplifier. The temperature of the drops is measured by observing the temperature dependent fluorescence intensity of cadmium selenide nanocrystals suspended in the water drops. We demonstrate characteristic heating times as short as 15 ms to steady-state temperatures as large as 30 degrees C above the base temperature of the microfluidi...

  16. Resection of Segments 4, 5 and 8 for a Cystic Liver Tumor Using the Double Liver Hanging Maneuver

    Atsushi Nanashima


    Full Text Available To achieve complete anatomic central hepatectomy for a large tumor compressing surrounding vessels, transection by an anterior approach is preferred but a skillful technique is necessary. We propose the modified technique of Belghiti’s liver hanging maneuver (LHM. The case was a 77-year-old female with a 6-cm liver cystic tumor in the central liver compressing hilar vessels and the right hepatic vein. At the hepatic hilum, the spaces between Glisson’s pedicle and hepatic parenchyma were dissected, which were (1 the space between the right anterior and posterior Glisson pedicles and (2 the space adjacent to the umbilical Glisson pedicle. Two tubes were repositioned in each space and ‘double LHM’ was possible at the two resected planes of segments 4, 5 and 8. Cut planes were easily and adequately obtained and the compressed vessels were secured. Double LHM is a useful surgical technique for hepatectomy for a large tumor located in the central liver.

  17. Digital video microscopy in the Millikan oil-drop experiment

    Silva, Kenneth J.; Mahendra, Jacquelyn C.


    We report on the ease and efficacy of using digital video microscopy techniques and computer software for analyzing data from the Millikan oil-drop experiment in an introductory physics laboratory course setting with applications for more advanced laboratories.

  18. Investigations of levitated helium drops

    Whitaker, Dwight Lawrence


    We report on the development of two systems capable of levitating drops of liquid helium. Helium drops of ˜20 mum have been levitated with the radiation pressure from two counter-propagating Nd:YAG laser beams. Drops are produced with a submerged piezoelectric transducer, and could be held for up to three minutes in our optical trap. Calculations show that Brillouin and Raman scattering of the laser light in the liquid helium produces a negligible rate of evaporation of the drop. Evaporation caused by the enhanced vapor pressure of the curved drop surfaces appears to be a significant effect limiting the drop lifetimes. Helium drops as large as 2 cm in diameter have been suspended in the earth's gravitational field with a magnetic field. A commercial superconducting solenoid provides the necessary field, field-gradient product required to levitate the drops. Drops are cooled to 0.5 K with a helium-3 refrigerator, and can be held in the trap indefinitely. We have found that when two or more drops are levitated in the same magnetic trap, the drops often remain in a state of apparent contact without coalescing. This effect is a result of the evaporation of liquid from between the two drops, and is found to occur only for normal fluid drops. We can induce shape oscillations in charged, levitated drops with an applied ac electric field. We have measured the resonance frequencies and damping rates for the l = 2 mode of oscillation as function of temperature. We have also developed a theory to describe the small amplitude shape oscillations of a He II drop surrounded by its saturated vapor. In our theory, we have considered two sets of boundary conditions---one where the drop does not evaporate and another in which the liquid and vapor are in thermodynamic equilibrium. We have found that both solutions give a frequency that agrees well with experiment, but that the data for the damping rate agree better with the solution without evaporation.

  19. Study of morphological changes in the skin of the neck in suicidal cases by hanging.

    Fernandez-Flores, Angel; Orduña, Oliva; Carranza, Veronica


    the morphologic changes in specimens from people who have committed suicide by hanging have mainly centered on macroscopic findings. Pour purpose is to inestigate the microscopis changes in the ligature marks. we report the histopathologic features of the ligature mark on the neck of three people who committed suicide by hanging themselves. the main Finding was coagulative necrosis of all cutaneous layers and the subjacent striated muscle. In the areas close to the ligature, blood vessels appeared congestive with a mild inflammatory perivasculary infiltrate. In some other areas, we found preserved sebaceous and eccrine glands, underneath the epidermis with marked necrotic changes. These findings suggest that neither pressure nor hypoxia is enough to induce necrosis in cutaneous adnexa.

  20. Level-3 BLAS on a GPU: Picking the low hanging fruit

    Igual, Francisco D.; Quintana-Ortí, Gregorio; van de Geijn, Robert A.


    The arrival of hardware accelerators has created a new gold rush to be the first to deliver their promise of high performance for numerical applications. Despite the recent advances in programmability, it is still hard to develop tuned programs that extract all the potential performance promised by the manufacturers. In this paper we remind the community that while this development effort is a noble endeavor, there is a lot of low hanging fruit that can be harvested easily. Picking this low hanging fruit benefits the scientific computing community immediately and prototypes the approach that further optimizations may follow. We demonstrate this by focusing on a widely used set of operations, the level-3 BLAS, targeting the NVIDIA GPUs.

  1. Increase in Suicide Rates by Hanging in the Population of Tabasco, Mexico between 2003 and 2012


    Background: Worldwide, the suicide rate is decreasing. To examine changes in the rates of completed suicide in the Mexican population from 2003 to 2012, we analyzed these changes according to: (i) the method of suicide; (ii) age group and (iii) gender. Methods: The data analyzed were obtained from governmental organizations from the State of Tabasco, Mexico. The data provided 1836 cases of subjects born and residing in Tabasco, who completed suicide in this state. Results: Suicide by hanging ...

  2. Residence time of water discharging from the Hanging Gardens of Zion Park

    Kimball, B.A.; Christensen, P.K.


    The Hanging Gardens are a unique feature of Zion National Park. Knowledge of the source and residence time of water discharging from the Hanging Gardens is necessary to help preserve these features. Ground-water chemical and isotopic data distinguish the discharge from seeps and springs into two groups, one of low and one of high conductivity. Water with low conductivity likely originates as recharge near the steps and springs, and it only interacts with the Navajo Sandstone. High conductivity water, on the other hand, originates as recharge on the tops of plateaus to the east, where it interacts with marine rocks of the Carmel Formation. Carbon dating of these ground waters indicates that the low conductivity water is essentially modern recharge, while the high conductivity water was recharged 1,000 to 4,000 years ago.The Hanging Gardens are a unique feature of Zion National Park. Knowledge of the source and residence time of water discharging from the Hanging Gardens is necessary to help preserve these features. Ground-water chemical and isotopic data distinguish the discharge from seeps and springs into two groups, one of low and one of high conductivity. Water with low conductivity likely originates as recharge near the seeps and springs, and it only interacts with the Navajo Sandstone. High conductivity water, on the other hand, originates as recharge on the tops of plateaus to the cast, where it interacts with marine rocks of the Carmel Formation. Carbon dating of these ground waters indicates that the low conductivity water is essentially modern recharge, while the high conductivity water was recharged 1,000 to 4,000 years ago.

  3. Sustainable groundwater development and management in the Quaternary Hang-Jia-Hu Plain, China



    Based on the results of study on regional water supply system, water quality assessments, Quaternary aquifers investigation, and correlation analysis of groundwater depression resulting from land subsidence in the Hang-Jia-Hu Quaternary Plain, this paper presents the groundwater resources policy and sustainable management methods suitable for this area. Suggestions for controlling land subsidence by implementation of wise groundwater policy and management measures are also given.

  4. Hanging angles of two electrostatically repelling pith balls of different masses

    Tran, Phuc G.; Mungan, Carl E.


    An analytic solution can be derived for the angles of two mutually repelling charged pith balls of unequal mass hanging from strings from a common point of attachment. Just as in the equal-mass case, a cubic equation is found for the square of the sine of either angle, and an approximation can be used to avoid Cardano's formula for small angles. These results extend a standard problem treated in introductory undergraduate courses in electricity and magnetism.

  5. How to optimize the drop plate method for enumerating bacteria.

    Herigstad, B; Hamilton, M; Heersink, J


    The drop plate (DP) method can be used to determine the number of viable suspended bacteria in a known beaker volume. The drop plate method has some advantages over the spread plate (SP) method. Less time and effort are required to dispense the drops onto an agar plate than to spread an equivalent total sample volume into the agar. By distributing the sample in drops, colony counting can be done faster and perhaps more accurately. Even though it has been present in the laboratory for many years, the drop plate method has not been standardized. Some technicians use 10-fold dilutions, others use twofold. Some technicians plate a total volume of 0.1 ml, others plate 0.2 ml. The optimal combination of such factors would be useful to know when performing the drop plate method. This investigation was conducted to determine (i) the standard deviation of the bacterial density estimate, (ii) the cost of performing the drop plate procedure, (iii) the optimal drop plate design, and (iv) the advantages of the drop plate method in comparison to the standard spread plate method. The optimal design is the combination of factor settings that achieves the smallest standard deviation for a fixed cost. Computer simulation techniques and regression analysis were used to express the standard deviation as a function of the beaker volume, dilution factor, and volume plated. The standard deviation expression is also applicable to the spread plate method.

  6. Wetting and absorption of water drops on Nafion films.

    Goswami, Sharonmoyee; Klaus, Shannon; Benziger, Jay


    Water drops on Nafion films caused the surface to switch from being hydrophobic to being hydrophilic. Contact angle hysteresis of >70 degrees between advancing and receding values were obtained by the Wilhelmy plate technique. Sessile drop measurements were consistent with the advancing contact angle; the sessile drop contact angle was 108 degrees . Water drop adhesion, as measured by the detachment angle on an inclined plane, showed much stronger water adhesion on Nafion than Teflon. Sessile water and methanol drops caused dry Nafion films to deflect. The flexure went through a maximum with time. Flexure increased with contact area of the drop, but was insensitive to the film thickness. Methanol drops spread more on Nafion and caused larger film flexure than water. The results suggest that the Nafion surface was initially hydrophobic but water and methanol drops caused hydrophilic sulfonic acid domains to be drawn to the Nafion surface. Local swelling of the film beneath the water drop caused the film to buckle. The maximum flexure is suggested to result from motion of a water swelling front through the Nafion film.




    Full Text Available Deaths by ligation of neck are in practice from the time immemorial and before advent of civilization. In uncivilized societies, the application of ligation for taking away the life of another person was one of the commonest practices which were successfu lly carried out into the civilized societies. Earliest it was a homicidal method as suicide was considered as a heinous act. Ligature mark is a pressure abrasion produced on the neck by ligature material due to force either from weight of the body or exter nal energies. More over the impression was ligation leads to wind pipe constriction for which manual violence is needed. When compared to other modalities of un - natural deaths, death by ligation was found world - wide popularity and is one of the preferred m ethods to take or take away the life. This study is conducted in the department of Forensic Medicine and Toxicology, Gandhi Medical College & Hospital, Secunderabad. The period of analytical study of ligature mark in cases of deaths due to hanging and liga ture strangulation is from Jan . 2012 to Dec . 2012. The total number of autopsies done during the year of 2012 is 4950, among the total Autopsies hanging & ligature strangulations deaths were 522. A detailed study of these 522 cases of deaths due to hanging a nd ligature strangulation were analyzed with special reference to ‘ligature mark’

  8. Scanned Hardcopy Maps, All Engineering hanging files: sewer, water, construction plans, and subdivisions, Published in 2008, City of Hutchinson.

    NSGIC GIS Inventory (aka Ramona) — This Scanned Hardcopy Maps dataset, was produced all or in part from Hardcopy Maps information as of 2008. It is described as 'All Engineering hanging files: sewer,...

  9. Gas Pressure-Drop Experiment

    Luyben, William L.; Tuzla, Kemal


    Most chemical engineering undergraduate laboratories have fluid mechanics experiments in which pressure drops through pipes are measured over a range of Reynolds numbers. The standard fluid is liquid water, which is essentially incompressible. Since density is constant, pressure drop does not depend on the pressure in the pipe. In addition, flow…

  10. Pressure drop in contraction flow

    Rasmussen, Henrik Koblitz

    This note is a supplement to Dynamic of Polymeric Liquids (DPL) page 178. DPL gives an equation for the pressure drop in a tapered (and circular) contraction, valid only at low angles. Here the general definition of contraction flow (the Bagley correction) and a more general method to find...... the pressure drop in a contraction are given....


    Hozumi, Koki; KOMODA, Masaki; Ono, Takatsugu; TSUKANO, Yukichi; 穂積, 弘毅; 古茂田, 真幸; 小野, 孝次; 塚野, 雄吉


    In order to investigate longitudinal force and moment characteristics of a hang-glider-wing, ground run tests were conducted using a test vehicle. A hang-glider-wing was installed on a test vehicle using a six-components-balance for wind tunnel use. Aerodynamic force and moment were measrued during the vehicle run at various constant speeds. Geometrical twist distribution along the wing span was recorded as well. Measured force and moment data were corrected for possible ground effect and upw...

  12. Optimization of transfection parameters for ultrasound/SonoVue microbubble-mediated hAng-1 gene delivery in vitro.

    Zhou, Qing; Chen, Jin-Ling; Chen, Qian; Wang, Xiao; Deng, Qing; Hu, Bo; Guo, Rui-Qiang


    This study aimed to explore the effects of microbubble concentration, gene dosage, cell-microbubble mixing mode and fetal bovine serum (FBS) on gene delivery. 293T cells were transfected with Sonovue microbubbles carrying the hAng-1 gene via ultrasound irradiation. Various ultrasound exposure parameters and microbubble and DNA concentrations were investigated. In addition, FBS and the cell suspension or adherent mode was explored. Transfection efficiency and cell viability were used to determine the optimal transfection parameters. hAng-1 gene transfection efficiency gradually increased with elongation of ultrasound exposure and increasing microbubble concentration. However, if ultrasound irradiation exceeded 1.5 W/cm² and 30 sec or the microbubble concentration was over 20%, hAng-1 gene expression was significantly decreased, coupled with extensive cell death. Gene transfection levels were low under DNA concentrations less than 15 µg/ml. Furthermore, the gene transfer rate was significantly increased under cell suspension mode; FBS had no effect on hAng-1 gene transfection. The integrity of hAng-1 DNA was not affected by ultrasonic irradiation under optimal conditions. The optimal transfection parameters for the hAng-1 gene and Sonovue microbubble were ultrasound exposure of 1.5 W/cm² and 30 sec, 20% microbubbles, 15 µg/ml of DNA and under cell suspension mode.

  13. Drop Test of the Candu Spent Fuel Storage Basket in MACSTOR/KN-400

    Choi, W.S.; Jeon, J.Y.; Seo, K.S. [KAERI, 1045 Daedeokdaero, Yuseong, Daejeon, 305-353 (Korea, Republic of); Park, J.E.; Yoo, G.S.; Park, W.G. [Korea Hydro Nuclear Power - KHNP (Korea, Republic of)


    The MACSTOR/KN-400 of Wolsung power plant in Korea is a dry interim storage facilities. There are 400 long slender cylinders in MACSTOR/KN-400. In one cylinder, ten baskets where Candu spent fuels are loaded are stacked and stored. For this MACSTOR/KN-400 facilities, analyses and tests for the hypothetical accident conditions that might happen during moving and storing baskets into a cylinder were performed. The hypothetical accident conditions to be considered are two cases. One is the case of basket dropping onto the bottom plate of a cylinder. The other is the case of basket dropping onto the other basket top plate stored in the cylinder. For the drop analyses, the case of hanging cylinder and the case of cylinder on the unyielding target surface were considered. Based on the dropping analysis, testing condition was determined as the latter case that is for the cylinder on the target surface. In a basket, 60 dummy fuel bundles are loaded which have the same weight of real spent fuel bundles. On the external surface of the basket, 8 strain gauges and 4 accelerometers were attached for the data acquisition. In order to measure the velocity when a basket impacts, three different devices were utilized. And the impact velocity results were compared and cross-checked. After the dropping tests, helium leak tests were conducted to evaluate the leakage rate. (authors)

  14. Liquid drops on soft solids

    Lubbers, Luuk A.; Weijs, Joost H.; Das, Siddhartha; Botto, Lorenzo; Andreotti, Bruno; Snoeijer, Jacco H.


    A sessile drop can elastically deform a substrate by the action of capillary forces. The typical size of the deformation is given by the ratio of surface tension and the elastic modulus, γ / E , which can reach up to 10-100 microns for soft elastomers. In this talk we theoretically show that the contact angles of drops on such a surface exhibit two transitions when increasing γ / E : (i) the microsocopic geometry of the contact line first develops a Neumann-like cusp when γ / E is of the order of few nanometers, (ii) the macroscopic angle of the drop is altered only when γ / E reaches the size of the drop. Using the same framework we then show that two neighboring drops exhibit an effective interaction, mediated by the deformation of the elastic medium. This is in analogy to the well-known Cheerios effect, where small particles at a liquid interface attract each other due to the meniscus deformations. Here we reveal the nature of drop-drop interactions on a soft substrate by combining numerical and analytical calculations.

  15. Excited Sessile Drops Perform Harmonically

    Chang, Chun-Ti; Steen, Paul H


    In our fluid dynamics video, we demonstrate our method of visualizing and identifying various mode shapes of mechanically oscillated sessile drops. By placing metal mesh under an oscillating drop and projecting light from below, the drop's shape is visualized by the visually deformed mesh pattern seen in the top view. The observed modes are subsequently identified by their number of layers and sectors. An alternative identification associates them with spherical harmonics, as demonstrated in the tutorial. Clips of various observed modes are presented, followed by a 10-second quiz of mode identification.

  16. Understanding (sessile/constrained) bubble and drop oscillations.

    Milne, A J B; Defez, B; Cabrerizo-Vílchez, M; Amirfazli, A


    The diffuse literature on drop oscillation is reviewed, with an emphasis on capillary wave oscillations of constrained drops. Based on the review, a unifying conceptual framework is presented for drop and bubble oscillations, which considers free and constrained drops/bubbles, oscillation of the surface or the bulk (i.e. center of mass) of the drop/bubble, as well as different types of restoring forces (surface tension, gravity, electromagnetic, etc). Experimental results (both from literature and from a new set of experiments studying sessile drops in cross flowing air) are used to test mathematical models from literature, using a novel whole profile analysis technique for the new experiments. The cause of oscillation (cross flowing air, vibrated surface, etc.) is seen not to affect oscillation frequency. In terms of models, simplified models are seen to poorly predict oscillation frequencies. The most advanced literature models are found to be relatively accurate at predicting frequency. However it is seen that no existing models are reliably accurate across a wide range of contact angles, indicating the need for advanced models/empirical relations especially for drops undergoing the lowest frequency mode of oscillation (the order 1 degree 1 non-axisymmetric 'bending' mode that corresponds to a lateral 'rocking' motion of the drop).

  17. Drop shape visualization and contact angle measurement on curved surfaces.

    Guilizzoni, Manfredo


    The shape and contact angles of drops on curved surfaces is experimentally investigated. Image processing, spline fitting and numerical integration are used to extract the drop contour in a number of cross-sections. The three-dimensional surfaces which describe the surface-air and drop-air interfaces can be visualized and a simple procedure to determine the equilibrium contact angle starting from measurements on curved surfaces is proposed. Contact angles on flat surfaces serve as a reference term and a procedure to measure them is proposed. Such procedure is not as accurate as the axisymmetric drop shape analysis algorithms, but it has the advantage of requiring only a side view of the drop-surface couple and no further information. It can therefore be used also for fluids with unknown surface tension and there is no need to measure the drop volume. Examples of application of the proposed techniques for distilled water drops on gemstones confirm that they can be useful for drop shape analysis and contact angle measurement on three-dimensional sculptured surfaces.

  18. Drop spreading with random viscosity

    Xu, Feng


    We examine theoretically the spreading of a viscous liquid drop over a thin film of uniform thickness, assuming the liquid's viscosity is regulated by the concentration of a solute that is carried passively by the spreading flow. The solute is assumed to be initially heterogeneous, having a spatial distribution with prescribed statistical features. To examine how this variability influences the drop's motion, we investigate spreading in a planar geometry using lubrication theory, combining numerical simulations with asymptotic analysis. We assume diffusion is sufficient to suppress solute concentration gradients across but not along the film. The solute field beneath the bulk of the drop is stretched by the spreading flow, such that the initial solute concentration immediately behind the drop's effective contact lines has a long-lived influence on the spreading rate. Over long periods, solute swept up from the precursor film accumulates in a short region behind the contact line, allowing patches of elevated v...


    Federal Laboratory Consortium — The Drop Tower is used to simulate and measure the impact shocks that are exerted on parachute loads when they hit the ground. It is also used for HSL static lift to...

  20. Water resources and effects of potential surface coal mining on dissolved solids in Hanging Woman Creek basin, southeastern Montana

    Cannon, M.R.


    Groundwater resources of the Hanging Woman Creek basin, Montana include Holocene and Pleistocene alluvial aquifers and sandstone , coal, and clinker aquifers in the Paleocene Fort Union Formation. Surface water resources are composed of Hanging Woman Creek, its tributaries, and small stock ponds. Dissolved-solids concentrations in groundwater ranged from 200 to 11,00 mg/L. Generally, concentrations were largest in alluvial aquifers and smallest in clinker aquifers. Near its mouth, Hanging Woman Creek had a median concentration of about 1,800 mg/L. Mining of the 20-foot to 35-foot-thick Anderson coal bed and 3-foot to 16-foot thick Dietz coal bed could increase dissolved-solids concentrations in shallow aquifers and in Hanging Woman Creek because of leaching of soluble minerals from mine spoils. Analysis of saturated-paste extracts from 158 overburden samples indicated that water moving through mine spoils would have a median increase in dissolved-solids concentration of about 3,700 mg/L, resulting in an additional dissolved-solids load to Hanging Woman Creek of about 3.0 tons/day. Hanging Woman Creek near Birney could have an annual post-mining dissolved-solids load of 3,415 tons at median discharge, a 47% increase from pre-mining conditions load. Post-mining concentrations of dissolved solids, at median discharge, could range from 2,380 mg/L in March to 3,940 mg/L in August, compared to mean pre-mining concentrations that ranged from 1,700 mg/L in July, November, and December to 2,060 mg/L in May. Post-mining concentrations and loads in Hanging Woman Creek would be smaller if a smaller area were mined. (USGS)

  1. The maid behind "The Handmaid’s Tale": A tainted view of Half-hanged Mary

    Anirban Chatterjee, MBBS


    Full Text Available Although much has been debated about the role of syphilis in the witch hunting craze that swept across Europe in the 16th and 17th Century, the equally horrifying Witch Trials in the United States of America were all bracketed under the common heading of ergotism. Here, I focus on one specific case in particular, which is peculiar owing to many factors, not the least being the fact that the woman who was hanged after being accused of witchcraft, eventually lived!

  2. Petechial hemorrhages of the tympanic membrane in attempted suicide by hanging

    Rasmussen, Eva Rye; Larsen, Per Leganger; Andersen, Kjeld


    of the eyes including the conjunctiva on both the upper and lower eyelids and photo documentation. Petechial hemorrhages of the conjunctiva are considered marker of life threatening hanging or strangulation. Hemorrhage from ears, perforated tympanic membrane and haematotympanum are scarcely described in case...... the fibrous layer. This assumption is made on the basis of our assessment of a normal tympanic membrane with light microscopy. Petechial hemorrhages of the tympanic membrane might in fact be the only sign of life threatening pressure applied to the neck. This is a very important finding and prospective...

  3. Ultrafast Drop Movements Arising from Curvature Gradient

    Lv, Cunjing; Chuang, Yin-Chuan; Tseng, Fan-Gang; Yin, Yajun; Zheng, Quanshui


    We report experimental observation of a kind of fast spontaneous movements of water drops on surfaces of cones with diameters from 0.1 to 1.5 mm. The observed maximum speed (0.22 m/s) under ambient conditions were at least two orders of magnitude higher than that resulting from any known single spontaneous movement mechanism, for example, Marangoni effect due to gradient of surface tension. We trapped even higher spontaneous movement speeds (up to 125 m/s) in virtual experiments for drops on nanoscale cones by using molecular dynamics simulations. The underlying mechanism is found to be universally effective - drops on any surface either hydrophilic or hydrophobic with varying mean curvature are subject to driving forces toward the gradient direction of the mean curvature. The larger the mean curvature of the surface and the lower the contact angle of the liquid are, the stronger the driving force will be. This discovery can lead to more effective techniques for transporting droplets.

  4. Biodynamic profiling of three-dimensional tissue growth techniques

    Sun, Hao; Merrill, Dan; Turek, John; Nolte, David


    Three-dimensional tissue culture presents a more biologically relevant environment in which to perform drug development than conventional two-dimensional cell culture. However, obtaining high-content information from inside three dimensional tissue has presented an obstacle to rapid adoption of 3D tissue culture for pharmaceutical applications. Biodynamic imaging is a high-content three-dimensional optical imaging technology based on low-coherence interferometry and digital holography that uses intracellular dynamics as high-content image contrast. In this paper, we use biodynamic imaging to compare pharmaceutical responses to Taxol of three-dimensional multicellular spheroids grown by three different growth techniques: rotating bioreactor, hanging-drop and plate-grown spheroids. The three growth techniques have systematic variations among tissue cohesiveness and intracellular activity and consequently display different pharmacodynamics under identical drug dose conditions. The in vitro tissue cultures are also compared to ex vivo living biopsies. These results demonstrate that three-dimensional tissue cultures are not equivalent, and that drug-response studies must take into account the growth method.

  5. Geometric effects resulting from the asym-metry of dipping fault: Hanging wall/foot-wall effects

    WANG Dong; XIE Li-li; HU Jin-jun


    Root-mean-square distance Drms with characteristic of weighted-average is introduced in this article firstly. Drms can be used to capture the general proximity of a site to a dipping fault plane comparing with the rupture distance Drup and the seismogenic distance Dseis. Then, using Drup Dseis and Drms, the hanging wall/footwall effects on the peak ground acceleration (PGA) during the 1999 Chi-Chi earthquake are evaluated by regression analysis. The logarithm residual shows that the PGA on hanging wall is much greater than that on footwall at the same Drup or Dseis when the Drup or Dseis is used as site-to-source distance measure. In contrast, there is no significant difference between the PGA on hanging wall and that on footwall at the same Drms when Drms is used. This result confirms that the hanging wall/footwall effect is mainly a geometric effect caused by the asymmetry of dipping fault. Therefore, the hanging wall/footwall effect on the near-fault ground motions can be ignored in the future attenuation analysis if the root-mean-square distance Drms is used as the site-to-source distance measure.

  6. Effects of hanging wall and forward directivity in the 1999 Chi-Chi earthquake on inelastic displacement response of structures

    Li Shuang; Xie Lili


    The characteristics of the inelastic response of structures affected by hanging wall and forward directivity in the 1999 Chi-Chi earthquake are investigated. Inelastic displacement ratios (IDRs) for ground motions impacted by these nearfield effects are evaluated and comprehensively compared to far-field ground motions. In addition, the inelastic displacement responses to hanging wall and footwall ground motions are compared. It is concluded that the inelastic displacement response is significantly affected in the short period range by hanging wall and in the long period range by footwall. Although high peak ground acceleration was observed at hanging wall stations, the IDRs for structures on hanging wall sites are only larger than footwall sites in the very long period range. Forward directivity effects result in larger IDRs for periods longer than about 0.5s. Adopting statistical relationships for IDRs established using far-field ground motions may lead to either overestimation or underestimation in the seismic evaluation of existing structures located in near-field regions, depending on their fundamental vibration periods.

  7. Assessment of the relative error in the automation task by sessile drop method

    T. О. Levitskaya


    Full Text Available Assessment of the relative error in the sessile drop method automation. Further development of the sessile drop method is directly related to the development of new techniques and specially developed algorithms enabling automatic computer calculation of surface properties. The sessile drop method mathematical apparatus improvement, drop circuit equation transformation to a form suitable for working, the drop surface calculation method automation, analysis of relative errors in the calculation of surface tension are relevant and are important in experimental determinations. The surface tension measurement relative error, as well as the error caused by the drop ellipsoidness in the plan were determined in the task of the sessile drop automation. It should be noted that if the drop maximum diameter (l is big or if the ratio of l to the drop height above the equatorial diameter(h is big, the relative error in the measurement of surface tension by sessile drop method does not depend much on the equatorial diameter of the drop and ellipsoidness of the drop. In this case, the accuracy of determination of the surface tension varies from 1,0 to 0,5%. At lower values the drop ellipsoidness begins to affect the relative error of surface tension (from 1,2 to 0,8%, but in this case the drop ellipsoidness is less. Therefore, in subsequent experiments, we used larger drops. On the basis of the assessment of the relative error in determining the liquid surface tension by sessile drop method caused by drop ellipsoidness in the plan, the tables showing the limits of the drop parameters (h and l measurement necessary accuracy to get the overall relative error have been made up. Previously, the surface tension used to be calculated with the relative error in the range of 2-3%

  8. D.R.O.P: The Durable Reconnaissance and Observation Platform

    McKenzie, Clifford; Parness, Aaron


    Robots can provide a remote presence in areas that are either inaccessible or too dangerous for humans. However, robots are often limited by their ability to adapt to the terrain or resist environmental factors. The Durable Reconnaissance and Observation Platform (DROP) is a lightweight robot that addresses these challenges with the capability to survive falls from significant heights, carry a useable payload, and traverse a variety of surfaces, including climbing vertical surfaces like wood, stone, and concrete. DROP is manufactured using a combination of rapid prototyping and shape deposition manufacturing. It uses microspine technology to create a new wheel-like design for vertical climbing. To date, DROP has successfully engaged several vertical surfaces, hanging statically without assistance, and traversed horizontal surfaces at approximately 30 cm/s. Unassisted vertical climbing is capable on surfaces up to 85deg at a rate of approximately 25cm*s(sup -1). DROP can also survive falls from up to 3 meters and has the ability to be thrown off of and onto rooftops. Future efforts will focus on improving the microspine wheels, selecting more resilient materials, customizing the controls, and performing more rigorous and quantifiable testing.

  9. Impact of water drops on small targets

    Rozhkov, A.; Prunet-Foch, B.; Vignes-Adler, M.


    The collision of water drops against small targets was studied experimentally by means of a high-speed photography technique. The drop impact velocity was about 3.5 m/s. Drop diameters were in the range of 2.8-4.0 mm. The target was a stainless steel disk of 3.9 mm diameter. The drop spread beyond the target like a central cap surrounded by a thin, slightly conical lamella bounded by a thicker rim. By mounting a small obstacle near the target, surface-tension driven Mach waves in the flowing lamella were generated, which are formally equivalent to the familiar compressibility driven Mach waves in gas dynamics. From the measurement of the Mach angle, the values of some flow parameters could be obtained as functions of time, which provided insight into the flow structure. The liquid flowed from the central cap to the liquid rim through the thin lamella at constant momentum flux. At a certain stage of the process, most of the liquid accumulated in the rim and the internal part of the lamella became metastable. In this situation, a rupture wave propagating through the metastable internal part of the lamella caused the rim to retract while forming outwardly directed secondary jets. The jets disintegrated into secondary droplets due to the Savart-Plateau-Rayleigh instability. Prior to the end of the retraction, an internal circular wave of rupture was formed. It originated at the target and then it propagated to meet the retracting rim. Their meeting resulted in a crown of tiny droplets. A theoretical analysis of the ejection process is proposed.

  10. Petechial hemorrhages of the tympanic membrane in attempted suicide by hanging: A case report.

    Rasmussen, Eva Rye; Larsen, Per Leganger; Andersen, Kjeld; Larsen, Michael; Qvortrup, Klaus; Hougen, Hans Petter


    It is important to determine whether a person has been strangulated and the diagnosis is not always straightforward since ligature marks are not always present. In forensic medicine the physical examination recommended is careful inspection of the head and neck region, oral cavity, examination of the eyes including the conjunctiva on both the upper and lower eyelids and photo documentation. Petechial hemorrhages of the conjunctiva are considered marker of life threatening hanging or strangulation. Hemorrhage from ears, perforated tympanic membrane and haematotympanum are scarcely described in case reports of strangulated patients. To our knowledge we are the first to report petechial hemorrhages of the tympanic membrane in a patient following attempted suicide by hanging. We believe that the petechial hemorrhages develop from the capillaries located in lamina propria of the epidermal layer above the fibrous layer. This assumption is made on the basis of our assessment of a normal tympanic membrane with light microscopy. Petechial hemorrhages of the tympanic membrane might in fact be the only sign of life threatening pressure applied to the neck. This is a very important finding and prospective studies should be conducted for further clarification on the matter. Copyright © 2012 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  11. [Safety provisions for recreational flying or sport with a hang-glider].

    Gennari, M; Lombardo, C


    The Act. n. 106 of 25th March 1985 had defined the specifications of the particular aircraft designed for hobby or sport flying as is the hang-glider. It has also provided for the issue, within six months, of special regulations aimed at "checking the psycho-physical fitness required in handling" such aircraft in additions to the technical knowledge and the information about traffic, safety, insurance regulations relevant to the matter. However, the patent default of the legislator causes the protection of hobby and sport practice of hang-gliding to be either wholly inadequate or ruled by ambiguous regulations. If, instead, the present law in force is referred to, it is deemed that--while waiting for the regulations provided for by n. 106 Act.--the Aereo Club of Italy may define as "agonistic" the practice of "hobby or sport flight" so that the checking of the "specific" fitness required by such sport comes into operation in compliance with the State Decree of 18th February 1982.

  12. Empirical Study on the Volatility of the Hang-Seng Index

    CAI Shi-Min; ZHOU Pei-Ling; YANG Hui-Jie; YANG Chun-Xia; WANG Bing-Hong; ZHOU Tao


    @@ We study the statistical properties of volatility of price fluctuation for the Hang-Seng index in the Hong Kong stock market, they are measured by locally averaging over a time window T, the absolute value of price change over a short time interval △t. The data include minute-by-minute records of the Hang-Seng index from 3 January 1994 to 28 May 1997. We find that the cumulative distribution of the volatility is consistent with the asymptotic power-law behaviour, characterized by the power exponent μ = 2.12 ± 0.04, different from that found in the previous studies as μ≈ 3. The volatility distribution remains the same asymptotic power-law behaviour for the time scales from T = 10 min to T = 80 min. Furthermore, we investigate the volatility correlations by using the power spectrum analysis and detrended fluctuation analysis. Both the methods show a long-range power-law decay with the exponent α = 0.636 ± 0.002.

  13. Empirical Study on the Volatility of the Hang-Seng Index

    Cai, Shi-Min; Zhou, Pei-Ling; Yang, Hui-Jie; Yang, Chun-Xia; Wang, Bing-Hong; Zhou, Tao


    We study the statistical properties of volatility of price fluctuation for the Hang-Seng index in the Hong Kong stock market, they are measured by locally averaging over a time window T, the absolute value of price change over a short time interval Δt. The data include minute-by-minute records of the Hang-Seng index from 3 January 1994 to 28 May 1997. We find that the cumulative distribution of the volatility is consistent with the asymptotic power-law behaviour, characterized by the power exponent μ = 2.12+/-0.04, different from that found in the previous studies as μapprox3. The volatility distribution remains the same asymptotic power-law behaviour for the time scales from T = 10 min to T = 80 min. Furthermore, we investigate the volatility correlations by using the power spectrum analysis and detrended fluctuation analysis. Both the methods show a long-range power-law decay with the exponent α = 0.636+/-0.002.

  14. Vortex-induced Vibration of a Flexible Free-hanging Circular Cantilever

    R. W. Prastianto


    Full Text Available An experimental investigation on time-dependent motion of a flexible free-hanging circular cantilever subjected to uniform cross-flows has been carried out. The free-end condition cantilever has a 34.4 aspect ratio and a low mass ratio of about 1.24. The cylinder freely oscillates in both inline and transverse to the flow. Reynolds number varied from 10,800 to 37,800. The “jump phenomenon” was also found in the inline motion of the cylinder that agrees well with an existing comparable work, even occurred at lower flow velocity, Ur, due to distinct conditions of the test. At high flow velocities, the 3rd higher harmonic frequencies of the cylinder transverse response became predominant that produce quite different motion characteristics compared to the other existing comparable works with 2-dimensional bottom-end condition, even same in bidirectional motion aspect. Generally, the results suggested that the flexible free-hanging cantilever generate different vortex wake mode than either, a uniform (a short-rigid flexibly-mounted cylinder or a linear amplitude variation along the span case (a pivoted cylinder.

  15. Detrended cross-correlation analysis on RMB exchange rate and Hang Seng China Enterprises Index

    Ruan, Qingsong; Yang, Bingchan; Ma, Guofeng


    In this paper, we investigate the cross-correlations between the Hang Seng China Enterprises Index and RMB exchange markets on the basis of a cross-correlation statistic test and multifractal detrended cross-correlation analysis (MF-DCCA). MF-DCCA has, at best, serious limitations for most of the signals describing complex natural processes and often indicates multifractal cross-correlations when there are none. In order to prevent these false multifractal cross-correlations, we apply MFCCA to verify the cross-correlations. Qualitatively, we find that the return series of the Hang Seng China Enterprises Index and RMB exchange markets were, overall, significantly cross-correlated based on the statistical analysis. Quantitatively, we find that the cross-correlations between the stock index and RMB exchange markets were strongly multifractal, and the multifractal degree of the onshore RMB exchange markets was somewhat larger than the offshore RMB exchange markets. Moreover, we use the absolute return series to investigate and confirm the fact of multifractality. The results from the rolling windows show that the short-term cross-correlations between volatility series remain high.

  16. Drop Spreading with Random Viscosity

    Xu, Feng; Jensen, Oliver


    Airway mucus acts as a barrier to protect the lung. However as a biological material, its physical properties are known imperfectly and can be spatially heterogeneous. In this study we assess the impact of these uncertainties on the rate of spreading of a drop (representing an inhaled aerosol) over a mucus film. We model the film as Newtonian, having a viscosity that depends linearly on the concentration of a passive solute (a crude proxy for mucin proteins). Given an initial random solute (and hence viscosity) distribution, described as a Gaussian random field with a given correlation structure, we seek to quantify the uncertainties in outcomes as the drop spreads. Using lubrication theory, we describe the spreading of the drop in terms of a system of coupled nonlinear PDEs governing the evolution of film height and the vertically-averaged solute concentration. We perform Monte Carlo simulations to predict the variability in the drop centre location and width (1D) or area (2D). We show how simulation results are well described (at much lower computational cost) by a low-order model using a weak disorder expansion. Our results show for example how variability in the drop location is a non-monotonic function of the solute correlation length increases. Engineering and Physical Sciences Research Council.

  17. Trapped liquid drop at the end of capillary.

    Wang, Zhengjia; Yen, Hung-Yu; Chang, Cheng-Chung; Sheng, Yu-Jane; Tsao, Heng-Kwong


    The liquid drop captured at the capillary end, which is observed in capillary valve and pendant drop technique, is investigated theoretically and experimentally. Because of contact line pinning of the lower meniscus, the lower contact angle is able to rise from the intrinsic contact angle (θ*) so that the external force acting on the drop can be balanced by the capillary force. In the absence of contact angle hysteresis (CAH), the upper contact angle remains at θ*. However, in the presence of CAH, the upper contact angle can descend to provide more capillary force. The coupling between the lower and upper contact angles determines the equilibrium shape of the captured drop. In a capillary valve, the pinned contact line can move across the edge as the pressure difference exceeds the valving pressure, which depends on the geometrical characteristic and wetting property of the valve opening. When CAH is considered, the valving pressure is elevated because the capillary force is enhanced by the receding contact angle. For a pendant drop under gravity, the maximal capillary force is achieved as the lower contact angle reaches 180° in the absence of CAH. However, in the presence of CAH, four regimes can be identified by three critical drop volumes. The lower contact angle can exceed 180°, and therefore the drop takes on the shape of a light bulb, which does not exist in the absence of CAH. The comparisons between Surface Evolver simulations and experiments are quite well.

  18. Application of Proteomics to the Study of Pollination Drops

    Natalie Prior


    Full Text Available Premise of the study: Pollination drops are a formative component in gymnosperm pollen-ovule interactions. Proteomics offers a direct method for the discovery of proteins associated with this early stage of sexual reproduction. Methods: Pollination drops were sampled from eight gymnosperm species: Chamaecyparis lawsoniana (Port Orford cedar, Ephedra monosperma, Ginkgo biloba, Juniperus oxycedrus (prickly juniper, Larix ×marschlinsii, Pseudotsuga menziesii (Douglas-fir, Taxus ×media, and Welwitschia mirabilis. Drops were collected by micropipette using techniques focused on preventing sample contamination. Drop proteins were separated using both gel and gel-free methods. Tandem mass spectrometric methods were used including a triple quadrupole and an Orbitrap. Results: Proteins are present in all pollination drops. Consistency in the protein complement over time was shown in L. ×marschlinsii. Representative mass spectra from W. mirabilis chitinase peptide and E. monosperma serine carboxypeptidase peptide demonstrated high quality results. We provide a summary of gymnosperm pollination drop proteins that have been discovered to date via proteomics. Discussion: Using proteomic methods, a dozen classes of proteins have been identified to date. Proteomics presents a way forward in deepening our understanding of the biological function of pollination drops.

  19. Estimating the unconfined yield strength of coal in the case of longwall coal mining with hanging wall top caving

    Hann, Damjan


    This study presents an innovative approach for determining the unconfined yield strength σc during the excavation of coal from the earth's crust by using an equipment that was developed for measuring the mechanical properties of bulk materials stored in silos. Highly productive excavation of coal with a hanging wall top caving leads to intensive deformations in the hanging wall and the broken coal can be considered as bulk material. In this research, the shear tester Johanson Hang-Up Indicizer was used to measure the unconfined yield strength of the tested samples, even though such a tester cannot produce stress-strain conditions similar to those occurring during the excavation. An attempt was made to estimate the real unconfined yield strength of broken coal deep under the surface through a combination of measured data and extrapolation.

  20. Drop stability in wind: theory

    Lee, Sungyon


    Water drops may remain pinned on a solid substrate against external forcing due to contact angle hysteresis. Schmucker and White investigated this phenomenon experimentally in a high Reynolds number regime, by measuring the critical wind velocity at which partially wetting water drops depin inside a wind tunnel. Due to the unsteady turbulent boundary layer, droplets are observed to undergo vortex-shedding induced oscillations. By contrast, the overall elongation of the drop prior to depinning occurs on a much slower timescale with self-similar droplet shapes at the onset. Based on these observations, a simple, quasi-static model of depinning droplet is developed by implementing the phenomenological description of the boundary layer. The resultant model successfully captures the critical onset of droplet motion and is the first of on-going studies that connect the classical boundary layer theory with droplet dynamics.

  1. Sticking around: an up-close look at drop adhesion

    Paxson, Adam T


    We present a fluid dynamics video showing the adhesion of a drop to a superhydrophobic surface. We use environmental scanning electron microscopy to observe depinning events at the microscale. As the drop moves along the surface, the advancing portion of the contact line simply lies down onto the upcoming roughness features, contributing negligibly to adhesion. After measuring the local receding contact angle of capillary bridges formed on a micropillar array, we find that these depinning events follow the Gibbs depinning criterion. We further extend this technique to two-scale hierarchical structures to reveal a self-similar depinning mechanism in which the adhesion of the entire drop depends only on the pinning at the very smallest level of roughness hierarchy. With this self-similar depinning mechanism we develop a model to predict the adhesion of drops to superhydrophobic surfaces that explains both the low adhesion on sparsely structured surfaces and the surprisingly high adhesion on surfaces whose featu...

  2. The role of drop velocity in statistical spray description

    Groeneweg, J. F.; El-Wakil, M. M.; Myers, P. S.; Uyehara, O. A.


    The justification for describing a spray by treating drop velocity as a random variable on an equal statistical basis with drop size was studied experimentally. A double-exposure technique using fluorescent drop photography was used to make size and velocity measurements at selected locations in a steady ethanol spray formed by a swirl atomizer. The size-velocity data were categorized to construct bivariate spray density functions to describe the spray immediately after formation and during downstream propagation. It was found that a statistical treatment of drop velocity was supported by the data. Spray density function shapes and modal characteristics depended strongly on position and the amount of droplet-gas interaction that had occurred. Bimodal density functions were formed by environmental interaction during downstream propagation. Large differences were also found between spatial mass density and mass flux size distributions at the same location.

  3. Incipient Condition of Hang-up in a Long Standpipe-Hopper System for Geldart-D Powders


    The incipient condition of hang-up for three Geldart-D powders has been experimentally studied in a 21 m long standpipe hopper system. Experimental results show that the pressure gradient for hang-up to occur is independent of the materials height in the hopper and the diameter of orifice and equals to (dpw/dl)s, which can be predicted by Eq. (7). While the corresponding gas velocity in the standpipe equals to the incipient fluidized velocity of particles at the high pressure and can be predicted by Kwauk's equation.

  4. Incipient Condition of Hang-up in a Long Standpipe-Hopper System for Geldart-D Powders

    景山; 蔡国斌; 黄晟; 王金福; 金涌


    The incipient condition of hang-up for three Geldart-D powders has been experimentally studied in a 21 m long standpipe hopper system. Experimental results show that the pressure gradient for hang-up to occur is independent of the materials height in the hopper and the diameter of orifice and equals to (dpw/dl)a, which can be predicted by Eq. (7). While the corresponding gas velocity in the standpipe equals to the incipient fluidized velocity of particles at the high pressure and can be predicted by Kwauk's equation.

  5. Calculation of Electric Field at Ground Surface and ADSS Cable Prepared Hanging Point near EHV Power Transmission Tower

    Xu Bao-Qing


    Full Text Available A simplified model of the 750kV tower is established by CDEGS software which is based on the Method Of Moment. The power frequency electric field distribution on the ground is achieved by software calculation and field-measuring. The validity of the calculation is proved when compare the calculation and experiment results. The model also can be used to calculate the electric field in prepared hanging points on the tower. Results show that the electric field distribution on the ground surface around the tower and prepared hanging points are meet the standard by calculation and experiment.

  6. Flat-ramp vs. convex-concave thrust geometries in a deformable hanging wall: new insights from analogue modeling experiments

    Almeida, Pedro; Tomas, Ricardo; Rosas, Filipe; Duarte, Joao; Terrinha, Pedro


    Different modes of strain accommodation affecting a deformable hanging-wall in a flat-ramp-flat thrust system were previously addressed through several (sandbox) analog modeling studies, focusing on the influence of different variables, such as: a) thrust ramp dip angle and friction (Bonini et al, 2000); b) prescribed thickness of the hanging-wall (Koy and Maillot, 2007); and c) sin-thrust erosion (compensating for topographic thrust edification, e.g. Persson and Sokoutis, 2002). In the present work we reproduce the same experimental procedure to investigate the influence of two different parameters on hanging-wall deformation: 1) the geometry of the thrusting surface; and 2) the absence of a velocity discontinuity (VD) that is always present in previous similar analogue modeling studies. Considering the first variable we use two end member ramp geometries, flat-ramp-flat and convex-concave, to understand the control exerted by the abrupt ramp edges in the hanging-wall stress-strain distribution, comparing the obtain results with the situation in which such edge singularities are absent (convex-concave thrust ramp). Considering the second investigated parameter, our motivation was the recognition that the VD found in the different analogue modeling settings simply does not exist in nature, despite the fact that it has a major influence on strain accommodation in the deformable hanging-wall. We thus eliminate such apparatus artifact from our models and compare the obtained results with the previous ones. Our preliminary results suggest that both investigated variables play a non-negligible role on the structural style characterizing the hanging-wall deformation of convergent tectonic settings were such thrust-ramp systems were recognized. Acknowledgments This work was sponsored by the Fundação para a Ciência e a Tecnologia (FCT) through project MODELINK EXPL/GEO-GEO/0714/2013. Pedro Almeida wants to thank to FCT for the Ph.D. grant (SFRH/BD/52556/2014) under the

  7. Axisymmetric Drop Shape Analysis: Computational Methods for the Measurement of Interfacial Properties from the Shape and Dimensions of Pendant and Sessile Drops.

    Río; Neumann


    State-of-the-art axisymmetric drop shape analysis (ADSA) techniques for the computation of interfacial tensions and contact angles by fitting the Laplace equation of capillarity to the shape and dimensions of pendant and sessile drops are presented. More accurate, efficient, and reliable versions of the technique for the measurement of contact angles from the volume and diameter of sessile drops [axisymmetric drop shape analysis-diameter (ADSA-D)] and for interfacial tension measurements from a series of arbitrary profile coordinates of sessile and pendant drops [axisymmetric drop shape analysis-profile (ADSA-P)] have been developed. Advanced numerical methods have been used to improve the numerical stability and global convergence, for more accurate results and a wider range of applicability of the methods. A new technique called axisymmetric drop shape analysis-height and diameter (ADSA-HD) has been developed to estimate interfacial tensions from the height and diameter of sessile and pendant drops. Numerical simulations using numerically generated drop profiles were used to evaluate the accuracy and applicability of the methods. Copyright 1997 Academic Press.

  8. An autopsy study of death due to Suicidal Hanging – 264 cases

    Dinesh Rao


    Full Text Available The present study was carried out between 2010 and 2013, a total of 7968 Autopsies were conducted of which 3.31% (n – 264 cases were deaths due to hanging. The most preferred ligature materials were Stole (n – 79 and Bed spread/Sari (n – 68. In 88% of the cases, hanging was complete. Females (n – 136 and males (n – 128 were equally affected. The major age group involved in both the sexes was of 31–40 years, contributing to 50.76% (n – 136 of the self suspension. In 80.58% (n – 213 of the incidents, ligature mark showed discontinuity (incomplete. A Slip type of knot was used in majority of the noose, contributing to 97.73% (n – 258 of the suspensions. In 87.88% (n – 232 of hanging an oblique shaped ligature mark was noticed. The horizontal and near oblique ligature marks were seen only in cases of partial suspension. In 95.45% (n – 252 of the cases, the ligature mark showed blackening of the skin (friction burn. Only 4.54% (n – 12 showed intact skin. The outer layer of the skin over the ligature mark showed displacement in majority of the cases. Married victims contributed to 70.45% of cases. Domestic issues were the commonest reason (n – 82 for self suspension, of which female (n – 68 formed the majority of victims. In 70.83% (n – 187 of cases damage to neck muscle fibers and hemorrhage at the Sternal end of the Sternocleidomastoid muscle were present. In 85.61% (n – 226 of cases the cervical vertebra was intact. In 52.27% (n – 138 of the cases the internal carotid artery showed transverse tear. In 99.42% (n – 248 cases the thyroid cartilage was found intact. The hyoid bone was damaged in 6.06% (n – 16 of the victims. Majority of the victims, 59.09% (n – 156 belonged to low socioeconomic class.

  9. Fluid flow in drying drops

    Gelderblom, H.


    When a suspension drop evaporates, it leaves behind a drying stain. Examples of these drying stains encountered in daily life are coffee or tea stains on a table top, mineral rings on glassware that comes out of the dishwasher, or the salt deposits on the streets in winter. Drying stains are also pr

  10. New identities for sessile drops

    Hajirahimi, Maryam; Fatollahi, Amir H


    A new set of mathematical identities is presented for axi-symmetric sessile drops on flat and curved substrates. The geometrical parameters, including the apex curvature and height, and the contact radius, are related by the identities. The validity of the identities are checked by various numerical solutions both for flat and curved substrates.

  11. Egg Drop: An Invention Workshop

    McCormack, Alan J.


    Describes an activity designed to stimulate elementary and junior high students to become actively engaged in thinking creatively rather than only analytically, convergently, or repetitively. The activity requires students to devise means of dropping an egg from a height without it breaking. (JR)

  12. Evaporating Drops of Alkane Mixtures

    Guéna, Geoffroy; Poulard, Christophe; Cazabat, Anne-Marie


    22 pages 9 figures; Alkane mixtures are model systems where the influence of surface tension gradients during the spreading and the evaporation of wetting drops can be easily studied. The surface tension gradients are mainly induced by concentration gradients, mass diffusion being a stabilising process. Depending on the relative concentration of the mixture, a rich pattern of behaviours is obtained.

  13. ``Quantum'' interference with bouncing drops

    Bohr, Tomas; Andersen, Anders; Madsen, Jacob; Reichelt, Christian; Lautrup, Benny; Ellegaard, Clive; Levinsen, Mogens


    In a series of recent papers (most recently) Yves Couder and collaborators have explored the dynamics of walking drops on the surface of a vibrated bath of silicon oil and have demonstrated a close analogy to quantum phenomena. The bouncing drop together with the surface wave that it excites seems to be very similar to the pilot wave envisaged by de Broglie for quantum particles. In particular, have studied a double slit experiment with walking drops, where an interference pattern identical to the quantum version is found even though it is possible to follow the orbits of the drops and unambigously determine which slit it goes through, something which in quantum mechanics would be ruled out by the Heisenberg uncertainly relations. We have repeated the experiment and present a somewhat more complicated picture. Theoretically, we study a Schrödinger equation with a source term originating from a localised ``particle'' being simultaneously guided by the wave. We present simple solutions to such a field theory and discuss the fundamental difficulties met by such a theory in order to comply with quantum mechanics.

  14. Drops, contact lines, and electrowetting

    Mannetje, 't D.J.C.M.


    In this work, we study the behaviour of drops and contact lines under the influence of electric fields, and how these can answer fundamental and industrial questions. Our focus is on studying the varying balance of the electric field, hysteresis forces and inertia as the speed of a contact line chan

  15. Evaporating Drops of Alkane Mixtures

    Gu'ena, G; Poulard, C; Cazabat, Anne-Marie; Gu\\'{e}na, Geoffroy; Poulard, Christophe


    Alkane mixtures are model systems where the influence of surface tension gradients during the spreading and the evaporation of wetting drops can be easily studied. The surface tension gradients are mainly induced by concentration gradients, mass diffusion being a stabilising process. Depending on the relative concentration of the mixture, a rich pattern of behaviours is obtained.

  16. Drops spreading on flexible fibers

    Somszor, Katarzyna; Boulogne, François; Sauret, Alban; Dressaire, Emilie; Stone, Howard


    Fibrous media are encountered in many engineered systems such as textile, paper and insulating materials. In most of these materials, fibers are randomly oriented and form a complex network in which drops of wetting liquid tend to accumulate at the nodes of the network. Here we investigate the role of the fiber flexibility on the spreading of a small volume of liquid on a pair of crossed flexible fibers. A drop of silicone oil is dispensed at the point of contact of the fibers and we characterize the liquid morphologies as we vary the volume of liquid, the angle between the fibers, and the length and bending modulus of the fibers. Drop morphologies previously reported for rigid fibers, i.e. a drop, a column and a mixed morphology, are also observed on flexible fibers with modified domains of existence. Moreover, at small inclination angles of the fibers, a new behavior is observed: the fibers bend and collapse. Depending on the volume, the liquid can adopt a column or a mixed morphology on the collapsed fibers. We rationalize our observations with a model based on energetic considerations. Our study suggests that the fiber flexibility adds a rich variety of behaviors that can be crucial for industrial applications.

  17. Pressure drop in contraction flow

    Rasmussen, Henrik Koblitz

    This note is a supplement to Dynamic of Polymeric Liquids (DPL) page 178. DPL gives an equation for the pressure drop in a tapered (and circular) contraction, valid only at low angles. Here the general definition of contraction flow (the Bagley correction) and a more general method to find...

  18. Buoyancy-induced squeezing of a deformable drop through an axisymmetric ring constriction

    Ratcliffe, Thomas; Zinchenko, Alexander Z.; Davis, Robert H.


    Axisymmetric boundary-integral (BI) simulations were made for buoyancy-induced squeezing of a deformable drop through a ring constriction. The algorithm uses the Hebeker representation for the solid-particle contribution. A high-order, near-singularity subtraction technique is essential for near-critical squeezing. The drop velocity and minimum drop-solid spacing were determined for different ring and hole sizes, viscosity ratios, and Bond numbers, where the latter is a dimensionless ratio of gravitational to interfacial forces. The drop velocity decelerates typically 100-fold or more, and the drop-solid spacing reduces to typically 0.1%-1% of the nondeformed drop radius as the drop passes through the constriction. The critical Bond number (below which trapping occurs) was determined for different conditions. For supercritical conditions, the nondimensional time required for the drop to pass through the ring increases for a fixed drop-to-hole size with increasing viscosity ratio and decreasing Bond number, but it has a nonmonotonic dependence on the ratio of the radii of the drop and ring cross section. Numerical results indicate that the square of the drop squeezing time is inversely proportional to the Bond number minus the critical Bond number for near-critical squeezing. The critical Bond number, determined from dynamic BI calculations, compares favorably to that obtained precisely from a static algorithm. The static algorithm uses the Young-Laplace equation to calculate the pendant and sessile portions of the drop interface coupled through the conditions of global pressure continuity and total drop volume conservation. Over a limited parameter space, the critical Bond number increases almost linearly with the drop-to-hole ratio and is a weak function of the ratio of the ring cross-sectional radius to the hole radius. Another dynamic phenomenon, in addition to drop squeezing, is a drop "dripping" around the outer edge of the ring constriction, and a critical

  19. Explanation for the Transverse Radiation Force Observed on a Vertically Hanging Fiber

    Brevik, Iver


    As shown in the experiment of She {\\it et al.} [Phys. Rev. Lett. {\\bf 101}, 243601 (2008)], a weak laser beam sent through a vertically hanging fiber exerts a transverse force and produces a lateral displacement of the fiber's lower end. The experiment is of obvious theoretical interest in connection with the electromagnetic theory of media. Suggested explanations given for this effect in the past include the famous Abraham-Minkowski issue concerning the "correct" photon momentum in matter. In our opinion such an explanation can hardly be right. Instead, we propose instead a very simple description of the effect implying that the sideways deflection is caused by the radiation force on the {\\it obliquely cut} lower end face of the fiber. From a calculation based upon geometrical optics, we find quite good agreement with the observations. We present also, as an alternative approach, a calculation involving wave optics instead of geometrical optics, and find comparable results.

  20. Time forecast of a break-off event from a hanging glacier

    Faillettaz, Jérome; Funk, Martin; Vagliasindi, Marco


    A cold hanging glacier located on the south face of the Grandes Jorasses (Mont Blanc, Italy) broke off on the 23 and 29 September 2014 with a total estimated ice volume of 105 000 m3. Thanks to accurate surface displacement measurements taken up to the final break-off, this event was successfully predicted 10 days in advance, enabling local authorities to take the necessary safety measures. The break-off event also confirmed that surface displacements experienced a power law acceleration along with superimposed log-periodic oscillations prior to the final rupture. This paper describes the methods used to achieve a satisfactory time forecast in real time and demonstrates, using a retrospective analysis, their potential for the development of early-warning systems in real time.

  1. Predictability of multifractal analysis of Hang Seng stock index in Hong Kong

    Sun, Xia; Chen, Huiping; Yuan, Yongzhuang; Wu, Ziqin


    In this paper, the daily Hang Seng index in Hong Kong stock market is studied by multifractal analysis. The main parameter of multifractal spectra used is Δ f, which can be used to characterize the ratio of number of highest index moments to that of lowest ones. The dependence of today's gain probability ( G%) and the day's index increase probability ( n%) with Δ f of the previous 3 days are studied. It is found that G% and n% can reach 70-80% at the large positive Δ f region and can be very close to 20% at the big negative Δ f region. The predictability decreases with the increasing number of the previous days.

  2. Displacements and identities in the australian gothic: the case of Picnic at Hanging Rock

    Luciana Wrege Rassier


    The mysteries of the novel Picnic at Hanging Rock, by Joan Lindsay (1967, and its film adaptation of same name, directed by Peter Weir (1975, have been intriguing readers and audiences for more than four decades. Set in the Australian countryside in 1900, both narratives illustrate the Australian Gothic genre by revolving around the mystery of the disappearance of three schoolgirls and a teacher from a repressive boarding school during a picnic at the mountain. Basing our approach on the reflections by Linda Hutcheon (2011 on adaptations we analyze to which extent literary and cinematographic works relate to each other, while the works presented by Susan Bassnett (2006 and Kristi Siegl (2004 on women’s travel writing will allow us to approach themes such as female sexuality and travel as a metaphor of transformation.


    Jacek NOWICKI


    Full Text Available The behaviour of weaners after mixing housed in pens equipped with hanging wooden ball, aromatized with vanilla fluid hanging wooden ball and without enrichment was evaluated. It was found that both enrichments reduced aggression, however the most interesting for weaners was the aromatized wooden ball.


    Jacek NOWICKI


    Full Text Available The behaviour of weaners after mixing housed in pens equipped with hanging fl exible, destructible object for biting, hanging non-destructible wooden ball and without enrichment was evaluated. It was found that both enrichments reduced aggression, however the most interesting for weaners was the object for biting.

  5. Nonabsorbable versus absorbable sutures in large, hang-back medial rectus muscle recessions.

    Awadein, Ahmed; Marsh, Justin D; Guyton, David L


    To investigate the value of nonabsorbable sutures in reducing the incidence of consecutive exotropia after large, "hang-back" medial rectus recessions. The medical records of patients who underwent medial rectus recession of ≥6.5 mm in individuals ≤2 years of age, or ≥7.0 mm in those >2 years were retrospectively reviewed. Patients were divided into two groups based on suture material used: absorbable, polyglactin 910 sutures (44 patients); nonabsorbable, polyester sutures (50 patients). Preoperative measurements, ductions, strabismus surgery, and postoperative results were analyzed. Inadequate anchoring of the medial rectus muscle was suspected when consecutive exotropia developed 4-7 weeks after surgery after initial satisfactory alignment and was confirmed if during reoperation the medial rectus muscle appeared recessed >2 mm beyond the originally intended recession. Consecutive exotropia due to inadequate anchoring of the medial rectus muscle occurred in 11 of 66 muscles (17%) in the absorbable suture group. The muscle was found 6-10 mm posterior to the intended recession. Limited duction in the field of action of the involved medial rectus muscle occurred in 9 of the 11 muscles (82%). None of the eyes with nonabsorbable sutures showed inadequate anchoring. The incidence of consecutive exotropia was higher in the absorbable suture group (30%) than in the nonabsorbable suture group (6%) (P < 0.005). Using nonabsorbable suture for large, hang-back medial rectus recessions greatly reduces the incidence of consecutive exotropia that can occur when absorbable suture dissolves. Copyright © 2016 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

  6. Effect of various loads on the force-time characteristics of the hang high pull.

    Suchomel, Timothy J; Beckham, George K; Wright, Glenn A


    The purpose of this study was to investigate the effect of various loads on the force-time characteristics associated with peak power during the hang high pull (HHP). Fourteen athletic men (age: 21.6 ± 1.3 years; height: 179.3 ± 5.6 cm; body mass: 81.5 ± 8.7 kg; 1 repetition maximum [1RM] hang power clean [HPC]: 104.9 ± 15.1 kg) performed sets of the HHP at 30, 45, 65, and 80% of their 1RM HPC. Peak force, peak velocity, peak power, force at peak power, and velocity at peak power were compared between loads. Statistical differences in peak force (p = 0.001), peak velocity (p < 0.001), peak power (p = 0.015), force at peak power (p < 0.001), and velocity at peak power (p < 0.001) existed, with the greatest values for each variable occurring at 80, 30, 45, 80, and 30% 1RM HPC, respectively. Effect sizes between loads indicated that larger differences in velocity at peak power existed as compared with those displayed by force at peak power. It seems that differences in velocity may contribute to a greater extent to differences in peak power production as compared with force during the HHP. Further investigation of both force and velocity at peak power during weightlifting variations is necessary to provide insight on the contributing factors of power production. Specific load ranges should be prescribed to optimally train the variables associated with power development during the HHP.

  7. Learning the Hang Power Clean: Kinetic, Kinematic, and Technical Changes in Four Weightlifting Naive Athletes.

    Haug, William B; Drinkwater, Eric J; Chapman, Dale W


    The investment in learning required to reach benefit with weightlifting training is currently not well understood in elite athletes. The purpose of this investigation was to quantify changes in vertical jump power production and kinematic variables in hang power clean (HPC) performance during the learning process from a naive state in a multiple single-subject research design. Four elite athletes undertook HPC learning for approximately 20-30 minutes twice per week over a 169-day period. Changes in parameters of vertical power production during squat jump (SJ) and countermovement jump (CMJ) were monitored from baseline (day 0) and at 3 additional occasions. Hang power clean movement kinematics and bar path traces were monitored from day 35 and at 3 additional occasions particular to the individual's periodized training plan. Descriptive statistics were reported within athletes as mean ± SD. We observed a 14.1-35.7% (SJ) and a -14.4 to 20.5% (CMJ) gain in peak power across the 4 jump testing occasions with improvements over the first 4 weeks (SJ: 9.2-32.6%; CMJ: -2.91 to 20.79%). Changes in HPC movement kinematics and barbell path traces occurred for each athlete indicating a more rearward-directed center of pressure over the concentric phase, greater double knee bend during the transition phase, decreased maximal plantar flexion, and minimal vertical displacement of body mass with HPC learning. Considering the minimal investment of 4 weeks to achieve increases in vertical power production, the benefits of training with HPC justified the associated time costs for these 4 elite athletes.

  8. Construct validity of a modification of the flexed arm hang test.

    Clemons, Jim M


    Despite the ubiquitous use of the flexed arm hang (FAH) as a field test of muscular fitness, evidence for the construct validity of it is lacking. The strongest validity coefficients (r) to date are 0.71 and 0.72 found by correlating modified versions of the FAH (i.e., 90 and 180° of elbow extension, respectively) with relative dynamic strength (i.e., 1 repetition maximum [1RM] lat pull downs × body mass). Considering a significant portion of all FAH and modified flexed arm hang (MFAH) performances are isometric, the test may be more correlated with the construct of relative isometric strength (RIS) rather than relative dynamic strength. The purpose of this study was to determine if the construct validity of the 90° MFAH might be strengthened by correlating it with either absolute isometric strength (AIS) (i.e., maximum volitional isometric contraction [MVIC]) or RIS (i.e., MVIC × body mass). Thirty-one college-aged women participated in the study. Inter-rater reliability coefficients for two 90° MFAH tests were determined using intraclass correlation coefficient (ICC): F1,30 = 1.356, ICC = 0.99; F1,30 = 0.675, ICC = 0.99. In addition, test-retest reliability was also found to be excellent: F1,30 = 3.809; ICC = 0.98. Pearson product moment correlation (r) was used at an adjusted alpha level of 0.025 to examine construct validity of the 90° MFAH with both AIS (MVIC) and RIS (MVIC × body mass). Results indicated no significant relationship with AIS (r = 0.096, p = 0.606); however, a strong significant relationship emerged with RIS (r = 0.878, p = 0.000). It was concluded that 90° MFAH scores alone were not related to absolute strength; however, they were found to be a valid and reliable estimate of the construct of RIS.

  9. The temporal nature of forces acting on metal drops in gas metal arc welding

    Jones, L.A.; Eagar, T.W.; Lang, J.H. [Massachusetts Institute of Technology, Cambridge, MA (United States)


    At moderate and high welding currents, the most important forces in gas metal arc welding acting on the molten electrode are magnetic forces arising from the interaction between the welding current and its own magnetic field. These forces drive the dynamic evolution of the drop and also depend on the instantaneous shape of the drop. In this paper, experimentally observed manifestations of magnetic forces are shown, and a technique for approximating the temporal evolution of these forces from experimentally measured drop shapes is reported. The technique provides quantitative data illustrating the large increase in the magnetic forces as a drop detaches from the electrode.

  10. Collecting responses through Web page drag and drop.

    Britt, M Anne; Gabrys, Gareth


    This article describes how to collect responses from experimental participants using drag and drop on a Web page. In particular, we describe how drag and drop can be used in a text search task in which participants read a text and then locate and categorize certain elements of the text (e.g., to identify the main claim of a persuasive paragraph). Using this technique, participants respond by clicking on a text segment and dragging it to a screen field or icon. We have successfully used this technique in both the argument element identification experiment that we describe here and a tutoring system that we created to teach students to identify source characteristics while reading historical texts (Britt, Perfetti, Van Dyke, & Gabrys, 2000). The implementation described here exploits the capability of recent versions of Microsoft's Internet Explorer Web browser to handle embedded XML documents and drag and drop events.

  11. Application of hanging anti-seepage curtain combined with recharge wells in deep foundation pit%悬挂式防渗帷幕与回灌井在深基坑施工工程中的应用



    In permeable ground, hanging anti-seepage curtain combined with recharge wells were used to control the underground water altitude surrounding the deep foundation pit during its excavation and lowering underground water in it.this technique is proved effective by practice.%在透水地层中的基坑降水工程,利用悬挂式防渗帷幕与回灌井对基坑周边地下水水位进行控制。工程实例表明,该技术效果显著。

  12. Toxicologic Laboratory Findings in Cases Reported with Hanging Death: a Two-Year Retrospective Study in Northeast Iran

    Mohammad Ranjbar


    How to cite this article: Ranjbar R, Liaghat AR, Ranjbar A, Mohabbati H. Toxicologic Laboratory Findings in Cases Reported with Hanging Death: a Two-Year Retrospective Study in Northeast Iran. Asia Pac J Med Toxicol 2013;2:92-5.

  13. A Flexible-Segment-Model-Based Dynamics Calculation Method for Free Hanging Marine Risers in Re-Entry

    XU Xue-song; WANG Sheng-wei


    In re-entry,the drilling riser hanging to the holding vessel takes on a free hanging state,waiting to be moved from the initial random position to the wellhead.For the re-entry,dynamics calculation is often done to predict the riser motion or evaluate the structural safety.A dynamics calculation method based on Flexible Segment Model (FSM) is proposed for free hanging marine risers.In FSM,a riser is discretized into a series of flexible segments.For each flexible segment,its deflection feature and external forces are analyzed independently.For the whole riser,the nonlinear governing equations are listed according to the moment equilibrium at nodes.For the solution of the nonlinear equations,a linearization iteration scheme is provided in the paper.Owing to its flexibility,each segment can match a long part of the riser body,which enables that good results can be obtained even with a small number of segments.Moreover,the linearization iteration scheme can avoid widely used Newton-Rapson iteration scheme in which the calculation stability is influenced by the initial points.The FSM-based dynamics calculation is timesaving and stable,so suitable for the shape prediction or real-time control of free hanging marine risers.

  14. Headspace liquid-phase microextraction of methamphetamine and amphetamine in urine by an aqueous drop

    He Yi [Department of Sciences, John Jay College of Criminal Justice, City University of New York, 445 W 59th Street, New York, NY 10019 (United States)]. E-mail:; Vargas, Angelica [Department of Sciences, John Jay College of Criminal Justice, City University of New York, 445 W 59th Street, New York, NY 10019 (United States); Kang, Youn-Jung [Department of Sciences, John Jay College of Criminal Justice, City University of New York, 445 W 59th Street, New York, NY 10019 (United States)


    This study developed a headspace liquid-phase microextraction (LPME) method by using a single aqueous drop in combination with high performance liquid chromatography (HPLC)-UV detection for the determination of methamphetamine (MAP) and amphetamine (AP) in urine samples. The analytes, volatile and basic, were released from sample matrix into the headspace first, and then protonated and dissolved in an aqueous H{sub 3}PO{sub 4} drop hanging in the headspace by a HPLC syringe. After extraction, this drop was directly injected into HPLC. Parameters affecting extraction efficiency were investigated and optimized. This method showed good linearity in the investigated concentration range of 1.0-1500 {mu}g L{sup -1}, repeatability of the extraction (R.S.D. < 5%, n = 6), and low detection limits (0.3 {mu}g L{sup -1} for both analytes). Enrichment factors of about 400-fold and 220-fold were achieved for MAP and AP, respectively, at optimum conditions. The feasibility of the method was demonstrated by analyzing human urine samples.

  15. Non-coalescence of oppositely charged drops

    Ristenpart, W D; Belmonte, A; Dollar, F; Stone, H A


    Oppositely charged drops have long been assumed to experience an attractive force that favors their coalescence. In this fluid dynamics video we demonstrate the existence of a critical field strength above which oppositely charged drops do not coalesce. We observe that appropriately positioned and oppositely charged drops migrate towards one another in an applied electric field; but whereas the drops coalesce as expected at low field strengths, they are repelled from one another after contact at higher field strengths. Qualitatively, the drops appear to `bounce' off one another. We directly image the transient formation of a meniscus bridge between the bouncing drops.

  16. How to freeze drop oscillations with powders

    Marston, Jeremy; Zhu, Ying; Vakarelski, Ivan; Thoroddsen, Sigurdur


    We present experiments that show when a water drop impacts onto a bed of fine, hydrophobic powder, the final form of the drop can be very different from the spherical form with which it impacts. For all drop impact speeds, the drop rebounds due to the hydrophobic nature of the powder. However, we observe that above a critical impact speed, the drop undergoes a permanent deformation to a highly non-spherical shape with a complete coverage of powder, thus creating a deformed liquid marble. This powder coating acts to freeze the drop oscillations during rebound.

  17. Dancing drops over vibrating substrates

    Borcia, Rodica; Borcia, Ion Dan; Helbig, Markus; Meier, Martin; Egbers, Christoph; Bestehorn, Michael


    We study the motion of a liquid drop on a solid plate simultaneously submitted to horizontal and vertical harmonic vibrations. The investigation is done via a phase field model earlier developed for describing static and dynamic contact angles. The density field is nearly constant in every bulk region (ρ = 1 in the liquid phase, ρ ≈ 0 in the vapor phase) and varies continuously from one phase to the other with a rapid but smooth variation across the interfaces. Complicated explicit boundary conditions along the interface are avoided and captured implicitly by gradient terms of ρ in the hydrodynamic basic equations. The contact angle θ is controlled through the density at the solid substrate ρ S , a free parameter varying between 0 and 1 [R. Borcia, I.D. Borcia, M. Bestehorn, Phys. Rev. E 78, 066307 (2008)]. We emphasize the swaying and the spreading modes, earlier theoretically identified by Benilov and Billingham via a shallow-water model for drops climbing uphill along an inclined plane oscillating vertically [E.S. Benilov, J. Billingham, J. Fluid Mech. 674, 93 (2011)]. The numerical phase field simulations will be completed by experiments. Some ways to prevent the release of the dancing drops along a hydrophobic surface into the gas atmosphere are also discussed in this paper.

  18. Novel approach to the oil-drop experiment

    Papirio, Anthony; Penchina, Claude M.; Sakai, Hajime


    Millikan's oil-drop experiment has limited accuracy. Using video-imaging techniques, students find the experiment less tedious and more interesting than using the microscope. By providing absolute calibration in the viewing field, and measuring distance directly, students now obtain improved accuracy.

  19. Star-shaped Oscillations of Leidenfrost Drops

    Ma, Xiaolei; Burton, Justin C


    We experimentally investigate the self-organized, star-shaped oscillations of Leidenfrost drops. The drops levitate on a cushion of evaporated vapor over a heated, curved surface. We observe modes with $n = 2-13$ lobes around the drop periphery. We find that both the wavelength and frequency of the oscillations depend only on the capillary length of the liquid, and are independent of the drop radius and substrate temperature. However, the number of observed modes depend sensitively on the liquid viscosity. The dominant frequency of pressure variations under the drop is approximately twice that the drop oscillation frequency, consistent with a parametric forcing mechanism. Our results suggest that the star-shaped oscillations are hydrodynamic in origin, and are driven by capillary waves beneath the drop. The exact mechanism by which the vapor flow initiates the capillary waves is likely related to static "brim waves" in levitated, viscous drops.

  20. Critical point wetting drop tower experiment

    Kaukler, W. F.; Tcherneshoff, L. M.; Straits, S. R.


    Preliminary results for the Critical Point Wetting CPW Drop Tower Experiment are produced with immiscible systems. Much of the observed phenomena conformed to the anticipated behavior. More drops will be needed to test the CPW theory with these immiscible systems.

  1. Nonlinear Resonance of Mechanically Excited Sessile Drops

    Chang, Chun-Ti; Daniel, Susan; Steen, Paul


    The spectrum of frequencies and mode shapes for an inviscid drop on a planar substrate have recently been documented. For vertical excitation, zonal modes respond to the driving frequency harmonically and non-zonal modes subharmonically, consistent with the prior literature. In this study, we report observations from the regime of nonlinear response. Here, zonals can respond non-harmonically, both sub- and super-harmonic responses are reported. The principal challenge to generating and observing superharmonic resonances of higher zonal modes is a mode-mixing behavior. However, using a simple visual simulation based on the ray-tracing technique, the individual contributions to the mixed resonance behavior can be extracted. In summary, results from experiment and theory show that the zonal modes, which respond harmonically and can mix with non-zonal modes without interfering with one another in the linear regime, tend to respond sub- or superharmonically and compete with non-zonal modes in the nonlinear regime.

  2. A preliminary description of the Gan-Hang failed rift, southeastern china

    Goodell, P. C.; Gilder, S.; Fang, X.


    The Gan-Hang failed rift, as defined by present-day topography, extends at least 450 km in length and 50 km in width. It is a northeast-southwest trending series of features spanning from Hangzhou Bay in Zhejiang province into Jiangxi province through Fuzhou City. Southwest of Fuzhou, the rift splits into two portions: one continuing along the southwestern trend, and the other diverging westward. The total extent of the rift cannot be defined at this time. The rift is superimposed upon a major suture zone of Caledonian or early Mesozoic age. The suture represents the fusing of the South China (Huanan) and Yangtze cratons. Perhaps in Late Triassic, but for sure by Late-Middle Jurassic time, the rifting was initiated and followed this older suture, in part. This time corresponds roughly to the middle stage of the Yanshanian orogeny and to the subduction of the postulated Pacific- Kula ridge southeast of the continental margin. The total thickness of the sediments and volcanics filling the rift valley reaches more than 10,000 m. Peak intensity of extension was between Late-Middle Jurassic and Middle to Late Cretaceous. Sedimentation within the rift was not continuous and is marked with periodic unconformities. Sediments within the rift include red beds, sandstones, siltstones, mudstones, conglomerates, breccias, tuffs, and ignimbrites. Vertebrate fossils and dinosaur eggs are also found. Contemporaneous volcanics within and flanking the rift include basalts, rhyolites, granites, gabbros, dacites, and andesites. Silicic volcanics are mostly attributed to caldera systems. Early basalts are tholeiitic and later change to alkaline-olivine basalt. Bimodal volcanism is recognized. Peak intensity of volcanism ranges between 135 and 75 Ma. In Early Cenozoic time, the area was a topographic low. Paleocene- Eocene sediments and evaporites are the last rocks to be deposited in the rift. Today the rift is delineated by major, high-angle faults (the Pingxiang-Guangfeng deep fault

  3. Electrohydrodynamics of a particle-covered drop

    Ouriemi, Malika; Vlahovska, Petia


    We study the dynamics of a drop nearly-completely covered with a particle monolayer in a uniform DC electric field. The weakly conducting fluid system consists of a silicon oil drop suspended in castor oil. A broad range of particle sizes, conductivities, and shapes is explored. In weak electric fields, the presence of particles increases drop deformation compared to a particle-free drop and suppresses the electrohydrodynamic flow. Very good agreement is observed between the measured drop deformation and the small deformation theory derived for surfactant-laden drops (Nganguia et al., 2013). In stronger electric fields, where drops are expected to undergo Quincke rotation (Salipante and Vlahovska, 2010), the presence of the particles greatly decreases the threshold for rotation and the stationary tilted drop configuration observed for clean drop is replaced by a spinning drop with either a wobbling inclination or a very low inclination. These behaviors resemble the predicted response of rigid ellipsoids in uniform electric fields. At even stronger electric fields, the particles can form dynamic wings or the drop implodes. The similar behavior of particle-covered and surfactant-laden drops provides new insights into understanding stability of Pickering emulsions. Supported by NSF-CBET 1437545.

  4. Spray characterization during vibration-induced drop atomization

    Vukasinovic, Bojan; Smith, Marc K.; Glezer, Ari


    Vibration-induced drop atomization is a process of rapid droplet ejection from a larger liquid drop. This occurs when a liquid drop resting on a thin diaphragm is vibrated under the appropriate forcing conditions using an attached piezoelectric actuator. The resulting spray of small droplets is characterized in this work using high-speed imaging and particle-tracking techniques. The results show that the average spatial and velocity distributions of the spray droplets are fairly axisymmetric during all stages of the atomization. The mean diameter of the droplets depends on the forcing frequency to the -2/3 power. The ejection velocity of the spray droplets depends on both the magnitude and the rate of change of the forcing amplitude. Thus, controlling the characteristics of the forcing signal may lead to strategies for controlling the spray process in specific applications.

  5. Poverty Eradication in Fragile Places: Prospects for Harvesting the Highest Hanging Fruit by 2030

    Gary Milante


    Full Text Available This paper explores the range of likely and potential progress on poverty eradication in fragile states to 2030. Using the International Futures model and recently released 2011 International Comparison Program data, this paper calculates current (2015 poverty for a US$1.90 poverty line, and subsequently runs three scenarios. The estimates suggest that there are 485 million poor in fragile states in 2015, a 33.5 per cent poverty rate. This paper’s Base Case scenario results in a forecasted 22.8 per cent poverty rate in fragile states by 2030. The most optimistic scenario yields a 13.1 per cent poverty rate for this group of countries (257 million. An optimistic scenario reflecting political constraints in fragile states yields a 19.1 per cent poverty rate (376 million. Even under the most optimistic circumstances, fragile states will almost certainly be home to hundreds of millions of poor in 2030, suggesting that the world must do things dramatically differently if we are to reach the high hanging fruit and truly ‘leave no one behind’ in the next fifteen years of development.

  6. An approach to Hang Seng Index in Hong Kong stock market based on network topological statistics


    Using homogenous partition of coarse graining process, the time series of Hang Seng Index (HSI) in Hong Kong stock market is transformed into discrete symbolic sequences S={S1S2S3…}, Si∈(R, r, d, D). Weighted networks of stock market are constructed by vertices that are 16 2-symbol strings (i.e. 16 patterns of HSI variations), and encode stock market relevant information about interconnections and interactions between fluctuation patterns of HSI in networks topology. By means of the measurements of betweenness centrality (BC) in networks, we have at least obtained 3 highest betweenness centrality uniform vertices in 2 order of magnitude of time subinterval scale, i.e. 18.7% vertices undertake 71.9% betweenness centrality of networks, showing statistical stability. These properties cannot be found in random networks; here vertices almost have identical betweenness centrality. By comparison to random networks, we conclude that Hong Kong stock market, rather than a random system, is statistically stable.

  7. Albrecht Ludwig Berblinger--inventor of the spring prosthesis and hang-glider (1811).

    Harsch, Viktor; Kriebel, Juergen


    Albrecht Ludwig Berblinger (1770-1829), known as the "Flying Tailor of Ulm", started with flight experiments in Ulm, Germany, in the early 19th century. He gained experience in downhill gliding with a maneuverable airworthy semi-rigid hang-glider and then attempted to cross the Danube River at Ulm's Eagle's Bastion on the 31st of May 1811. The tricky local winds caused him to crash and he was rescued by fishermen, making him the first survivor of a water immersion accident of a heavier-than-air manned "flight machine". Though he failed in his attempt to be the first man to fly, Berblinger can be regarded as one of the significant aviation pioneers who applied the "heavier than air" principle and paved the way for the more effective glide-flights of Otto Lilienthal (1891) and the Wright Brothers (1902). Less known are Berblinger's significant contributions to the construction of artificial limbs for medical use, as well as the spring-application in aviation. His invention of a special mechanical joint was also used for the juncture of the wings of his "flying machine". Because of his worthwhile contributions to medicine and flight, in 1993 the German Academy of Aviation Medicine named an annual award for young scientists in the field of aerospace medicine in his honor.

  8. Heart rate responses and fluid balance of competitive cross-country hang gliding pilots.

    Morton, Darren P


    To evaluate the physiological challenges of competitive cross-country hang gliding. Seventeen experienced male pilots (age=41+/-9 y; mean+/-SD) were fitted with a monitor that recorded heart rate and altitude at 0.5 Hz throughout a competitive flight. Fluid losses were evaluated by comparing pilot pre- and postflight mass. The pilots' displacement was 88.4+/-43.7 km in 145.5+/-49.4 min. Mean flight altitude was 1902+/-427 m (range=1363-2601 m) with a maximum altitude of 2925+/-682 m (1870-3831 m). The mean in-flight heart rate of the pilots was 112+/-11 bpm (64+/-6% predicted HRmax). For all except one subject, heart rate was highest while launching (165+/-12 bpm, 93+/-7% predicted HRmax), followed by landing (154+/-13 bpm, 87+/-7% predicted HRmax). No statistically significant relationship was observed between heart rate during the launch and reported measures of state anxiety. Heart rate was inversely related (PFluid loss during the flight was 1.32+/-0.70 L, which approximated 0.55 L/h, while mean in-flight fluid consumption was 0.39+/-0.44 L. Six pilots consumed no fluid during the flight. Even among experienced pilots, high heart rates are more a function of state anxiety than physical work demand. Fluid losses during flight are surprisingly moderate but pilots may still benefit from attending to fluid balance.

  9. Experimental study of drop impacts on soap films

    Yawar, Ali; Basu, Saikat; Concha, Andres; Bandi, Mahesh


    Impinging drops on flowing and static soap films demonstrate at least three distinct types of impact regimes: (a) the drop bounces off the film surface, (b) it coalesces with the downstream flow for a moving film and for static films it gets assimilated within the film, and (c) it pierces through the film. The interaction presents a unique opportunity to explore the impact of a quasi one-dimensional object on a two-dimensional fluid, much like a comet impacting on a thin atmosphere. We present a detailed experimental study of droplet impacts on soap film flow, for a number of film inclination angles and falling heights of the drop. Imaging techniques employed include sodium lamp interferometry to measure film thickness fluctuations and particle tracking velocimetry to measure the velocity field. Film thickness measures approximately 10 microns and the drop diameter is 1 mm. We mostly observe the bouncing-off regime for smaller inclination angles. However, at higher impact angles, puncturing of the film becomes a more common occurrence. We show that when the drop bounces off the film, there is a momentum transfer leading to vortex dipole shedding, along with the generation of capillary waves; an impulsive regime that may share correspondence with the locomotion of water striders.

  10. A Novel Virus Causes Scale Drop Disease in Lates calcarifer.

    Ad de Groof


    Full Text Available From 1992 onwards, outbreaks of a previously unknown illness have been reported in Asian seabass (Lates calcarifer kept in maricultures in Southeast Asia. The most striking symptom of this emerging disease is the loss of scales. It was referred to as scale drop syndrome, but the etiology remained enigmatic. By using a next-generation virus discovery technique, VIDISCA-454, sequences of an unknown virus were detected in serum of diseased fish. The near complete genome sequence of the virus was determined, which shows a unique genome organization, and low levels of identity to known members of the Iridoviridae. Based on homology of a series of putatively encoded proteins, the virus is a novel member of the Megalocytivirus genus of the Iridoviridae family. The virus was isolated and propagated in cell culture, where it caused a cytopathogenic effect in infected Asian seabass kidney and brain cells. Electron microscopy revealed icosahedral virions of about 140 nm, characteristic for the Iridoviridae. In vitro cultured virus induced scale drop syndrome in Asian seabass in vivo and the virus could be reisolated from these infected fish. These findings show that the virus is the causative agent for the scale drop syndrome, as each of Koch's postulates is fulfilled. We have named the virus Scale Drop Disease Virus. Vaccines prepared from BEI- and formalin inactivated virus, as well as from E. coli produced major capsid protein provide efficacious protection against scale drop disease.

  11. Drop shaping by laser-pulse impact

    Klein, Alexander L; Visser, Claas Willem; Lhuissier, Henri; Sun, Chao; Snoeijer, Jacco H; Villermaux, Emmanuel; Lohse, Detlef; Gelderblom, Hanneke


    We study the hydrodynamic response of a falling drop hit by a laser pulse. Combining high-speed with stroboscopic imaging we report that a millimeter-sized dyed water drop hit by a milli-Joule nanosecond laser-pulse deforms and propels forward at several meters per second, until it eventually fragments. We show that the drop motion results from the recoil momentum imparted at the drop surface by water vaporization. We measure the propulsion speed and the time-deformation law of the drop, complemented by boundary integral simulations. We explain the drop propulsion and shaping in terms of the laser pulse energy and drop surface tension. These findings are crucial for the generation of extreme ultraviolet (EUV) light in lithography machines.

  12. Unstable Leidenfrost Drops on Roughened Surfaces

    Boreyko, Jonathan B


    Drops placed on a surface with a temperature above the Leidenfrost point float atop an evaporative vapor layer. In this fluid dynamics video, it is shown that for roughened surfaces the Leidenfrost point depends on the drop size, which runs contrary to previous claims of size independence. The thickness of the vapor layer is known to increase with drop radius, suggesting that the surface roughness will not be able to penetrate the vapor layer for drops above a critical size. This size dependence was experimentally verified: at a given roughness and temperature, drops beneath a critical size exhibited transition boiling while drops above the critical size were in the Leidenfrost regime. These Leidenfrost drops were unstable; upon evaporation down to the critical size the vapor film suddenly collapsed.

  13. Finite Element Analysis of the Effect on Edge Distance of the Tensile Bearing Capacity of Embedded Hanging Parts

    Meng Xian Hong; Liu Wei


    In order to explore the trend of tensile bearing capacity of embedded hanging parts when change the edge distance. Based on the finite element analysis software ABAQUS, the four simulation model was established. The buried depth and strength of concrete remain unchanged, but the edge distance was gradient change. By the load - displacement curve of every model known, the greater the edge distance, the greater the bearing capacity. When the edge distance reaches 1.5 times buried depth, the eff...

  14. Flow Visualization in Evaporating Liquid Drops and Measurement of Dynamic Contact Angles and Spreading Rate

    Zhang, Neng-Li; Chao, David F.


    A new hybrid optical system, consisting of reflection-refracted shadowgraphy and top-view photography, is used to visualize flow phenomena and simultaneously measure the spreading and instant dynamic contact angle in a volatile-liquid drop on a nontransparent substrate. Thermocapillary convection in the drop, induced by evaporation, and the drop real-time profile data are synchronously recorded by video recording systems. Experimental results obtained from this unique technique clearly reveal that thermocapillary convection strongly affects the spreading process and the characteristics of dynamic contact angle of the drop. Comprehensive information of a sessile drop, including the local contact angle along the periphery, the instability of the three-phase contact line, and the deformation of the drop shape is obtained and analyzed.

  15. Effects of the hanging wall and footwall on peak acceleration during the Jiji (Chi-Chi), Taiwan Province, earthquake


    The M=7.6 Jiji (Chi-Chi) earthquake, Taiwan Province, on September 21, 1999 (local time) is a thrust fault style earthquake. The empirical attenuation relations of the horizontal and vertical peak ground accelerations (PGA) for the Jiji (Chi-Chi) earthquake are developed by regression method. By examining the residuals from the Jiji (Chi-Chi) earthquake-specific peak acceleration attenuation relations, it is found that there are systematic differences between PGA on the hanging-wall and footwall. The recorded peak accelerations are higher on the hanging-wall and lower on the footwall. The clear asymmetry of PGA distribution to the surface rupture trace can also be seen from the PGA contour map. These evidences indicate that the PGA attenuates faster on the hanging-wall than on the footwall. In the study of near-source strong motion, seismic hazard assessment, scenario earthquake and seis-mic disaster prediction, the style-of-faulting must be considered in order that the attenuation model can reflect the characteristic of ground motion in various seismic environmental regions.

  16. Magnetoplasma excitations and the effect of electron and hole velocity renormalization in free-hanging graphene studied by Raman scattering

    Kukushkin, V. I.; Kirpichev, V. E.; Kukushkin, I. V.


    The properties of plasma and magnetoplasma excitations in free-hanging graphene have been studied for the first time by Raman scattering. In addition to single-particle excitations associated with transitions between empty Landau levels of electrons and holes, collective plasma and magnetoplasma excitations in the system of electrons (and holes) of various densities have been discovered for the first time. Hybridization of plasma and cyclotron modes corresponding to the Kohn law has been shown to occur in the limit of high filling factors, which allows measuring directly the plasma and cyclotron energies. The dependence of the electron and hole velocities on their density has been investigated via the magnetic-field dependence of the cyclotron energy in free-hanging graphene. The effect of strong renormalization of the electron and hole dispersion relations seen as an increase in the velocity (by 40-50%) with a decrease in the charge-carrier density to 1011 cm-2 has been discovered. The charge-carrier density dependences of the widths of magnetoplasma resonances in free-hanging graphene and graphene lying on a silicon dioxide surface have been measured and shown to be at least 3.5 and 14.8 meV, respectively.

  17. [Hangings in the material of Department of Forensic Medicine, Nicolaus Copernicus University Collegium Medicum in Bydgoszcz, in the years 2000-2010].

    Sumińska-Ziemann, Barbara; Bloch-Bogusławska, Elzbieta


    This study presents an analysis of suicides based on autopsy protocols from the years 2000-2010. Out of all autopsies conducted at Department of Forensic Medicine, Nicolaus Copernicus University Collegium Medicum in Bydgoszcz, 477 cases resulted from hanging. During this period the majority of hangings were recorded in 2010 (61 cases). The parameters assessed in this study included age, sex, post-mortem blood ethanol concentration and place of death of the victims. The age range of the deceased was similar in the group of men and women. Males represented the majority of victims of hanging (89%); only 11% of all the victims were females. The authors observed differences in blood alcohol level of the victims in association with their sex. Not present ethanol was noted in approx. 42% of men and 71% of women. More than 65% cases of suicide hangings were encountered in urban areas, in living quarters and outbuildings.

  18. Leidenfrost drops on a heated liquid pool

    Maquet, L.; Sobac, B.; Darbois-Texier, B.; Duchesne, A.; Brandenbourger, M.; Rednikov, A.; Colinet, P.; Dorbolo, S.


    We show that a volatile liquid drop placed at the surface of a nonvolatile liquid pool warmer than the boiling point of the drop can be held in a Leidenfrost state even for vanishingly small superheats. Such an observation points to the importance of the substrate roughness, negligible in the case considered here, in determining the threshold Leidenfrost temperature. A theoretical model based on the one proposed by Sobac et al. [Phys. Rev. E 90, 053011 (2014), 10.1103/PhysRevE.90.053011] is developed in order to rationalize the experimental data. The shapes of the drop and of the liquid substrate are analyzed. The model notably provides scalings for the vapor film thickness profile. For small drops, these scalings appear to be identical to the case of a Leidenfrost drop on a solid substrate. For large drops, in contrast, they are different, and no evidence of chimney formation has been observed either experimentally or theoretically in the range of drop sizes considered in this study. Concerning the evaporation dynamics, the radius is shown to decrease linearly with time whatever the drop size, which differs from the case of a Leidenfrost drop on a solid substrate. For high superheats, the characteristic lifetime of the drops versus the superheat follows a scaling law that is derived from the model, but, at low superheats, it deviates from this scaling by rather saturating.

  19. That's one small drop for Mankind...

    Anaïs Schaeffer


    In August, the members of an ISOLDE project called LOI88 successfully employed a new technique to study the interaction of metal ions in a liquid. It’s the first time that specific ions have been studied in a liquid medium - a technical achievement that opens promising doors for biochemistry.   In the heart of the LOI88 experiment: this is the point where the metal ions (from the left) enter the drop.  “More than half of the proteins in the human body contain metal ions such as magnesium, zinc and copper,” explains Monika Stachura, a biophysicist at the University of Copenhagen and the LOI88 project leader. “We know that these elements are crucial to a protein’s structure and function but their behaviour and interactions are not known in detail.” Detecting these ions directly in  a body-like environment is problematic as their closed atomic shells make them invisible to most spectroscopic techniques. However, using ...

  20. The sweet branch of metabolic engineering: cherry-picking the low-hanging sugary fruits.

    Chen, Rachel


    In the first science review on the then nascent Metabolic Engineering field in 1991, Dr. James E. Bailey described how improving erythropoietin (EPO) glycosylation can be achieved via metabolic engineering of Chinese hamster ovary (CHO) cells. In the intervening decades, metabolic engineering has brought sweet successes in glycoprotein engineering, including antibodies, vaccines, and other human therapeutics. Today, not only eukaryotes (CHO, plant, insect, yeast) are being used for manufacturing protein therapeutics with human-like glycosylation, newly elucidated bacterial glycosylation systems are enthusiastically embraced as potential breakthrough to revolutionize the biopharmaceutical industry. Notwithstanding these excitement in glycoprotein, the sweet metabolic engineering reaches far beyond glycoproteins. Many different types of oligo- and poly-saccharides are synthesized with metabolically engineered cells. For example, several recombinant hyaluronan bioprocesses are now in commercial production, and the titer of 2'-fucosyllactose, the most abundant fucosylated trisaccharide in human milk, reaches over 20 g/L with engineered E. coli cells. These successes represent only the first low hanging fruits, which have been appreciated scientifically, medically and fortunately, commercially as well. As one of the four building blocks of life, sugar molecules permeate almost all aspects of life. They are also unique in being intimately associated with all major types of biopolymers (including DNA/RNA, proteins, lipids) meanwhile they stand alone as bioactive polysaccharides, or free soluble oligosaccharides. As such, all sugar moieties in biological components, small or big and free or bound, are important targets for metabolic engineering. Opportunities abound at the interface of glycosciences and metabolic engineering. Continued investment and successes in this branch of metabolic engineering will make vastly diverse sugar-containing molecules (a

  1. NASA SOFIA International Year of Light (IYL) Event: Infrared Light: Hanging out in the Stratosphere

    Clark, Coral; Backman, Dana E.; Harman, Pamela; Veronico, Nicholas


    As an International Year of Light committee endorsed event, Infrared Light: Hanging out in the Stratosphere will engage learners around the world, linking participants with scientists at work on board NASA SOFIA, the world's largest flying observatory. This major event will showcase science-in-action, interviews, live data, and observations performed both aboard the aircraft and at partner centers on land.SOFIA (Stratospheric Observatory For Infrared Astronomy) is an 80% - 20% partnership of NASA and the German Aerospace Center (DLR) consisting of an extensively modified Boeing 747SP aircraft carrying a reflecting telescope with an effective diameter of 2.5 meters. SOFIA is a program in NASA's Science Mission Directorate, Astrophysics Division. Science investigators leverage SOFIA's unique capabilities to study the universe at infrared wavelengths by making observations that are impossible for even the largest and highest ground-based telescopes. SOFIA received Full Operating Capacity status in May, 2014, and astrophysicists will continue to utilize the observatory and upgraded instruments to study astronomical objects and phenomena, including star birth and death; planetary system formation; identification of complex molecules in space; planets, comets, and asteroids in our solar system; and nebulae and dust in galaxies.This landmark event will reflect and build on the ProjectLink. In October 1995, SOFIA's predecessor, the Kuiper Airborne Observatory (KAO), performed the first satellite links from an airplane to the ground. The KAO downlinked to the Exploratorium museum (SF, CA), where over 200 students watched the webcast, conversed, and participated in simultaneous observations at the world-renowned science museum. SOFIA will now take this concept into the 21st century, utilizing internet technologies to engage and inspire 100,000+ learners of all ages through simultaneous presentations and appearances by over 70 SOFIA Educators at schools and informal learning

  2. Footprint Geometry and Sessile Drop Resonance

    Chang, Chun-Ti; Daniel, Susan; Steen, Paul H.


    How does a sessile drop resonate if its footprint is square (square drop)? In this talk, we discuss the two distinct families of observed modes in our experiments. One family (spherical modes) is identified with the natural modes of capillary spherical caps, and the other (grid modes) with Faraday waves on a square bath (square Faraday waves). A square drop exhibits grid or spherical modes depending on its volume, and the two families of modes arise depending on how wavenumber selection of footprint geometry and capillarity compete. For square drops, a dominant effect of footprint constraint leads to grid modes which are constrained response; otherwise the drops exhibit spherical modes, the characteristic of sessile drops on flat plates. Chun-Ti Chang takes his new position at National Taiwan University on Aug. 15th, 2016. Until then, Chun-Ti Chang is affiliated with Technical University Dortmund, Germany.

  3. Sepsis from dropped clips at laparoscopic cholecystectomy

    Hussain, Sarwat E-mail:


    We report seven patients in whom five dropped surgical clips and two gallstones were visualized in the peritoneal cavity, on radiological studies. In two, subphrenic abscesses and empyemas developed as a result of dropped clips into the peritoneal cavity during or following laparoscopic cholecystectomy. In one of these two, a clip was removed surgically from the site of an abscess. In two other patients dropped gallstones, and in three, dropped clips led to no complications. These were seen incidentally on studies done for other indications. Abdominal abscess secondary to dropped gallstones is a well-recognized complication of laparoscopic cholecystectomy (LC). We conclude that even though dropped surgical clips usually do not cause problems, they should be considered as a risk additional to other well-known causes of post-LC abdominal sepsis.

  4. A Different Cone: Bursting Drops in Solids

    Zhao, Xuanhe


    Drops in fluids tend to be spheres--a shape that minimizes surface energy. In thunderstorm clouds, drops can become unstable and emit thin jets when charged beyond certain limits. The instability of electrified drops in gases and liquids has been widely studied and used in applications including ink-jet printing, electrospinning nano-fibers, microfluidics and electrospray ionization. Here we report a different scenario: drops in solids become unstable and burst under sufficiently high electric fields. We find the instability of drops in solids morphologically resembles that in liquids, but the critical electric field for the instability follows a different scaling due to elasticity of solids. Our observations and theoretical models not only advance the fundamental understanding of electrified drops but also suggest a new failure mechanism of high-energy-density dielectric polymers, which have diverse applications ranging from capacitors for power grids and electric vehicles to muscle-like transducers for soft robots and energy harvesting.

  5. Instrumentation and data acquisition electronics for free-flight drop model testing

    Carraway, Preston I., III


    This paper presents instrumentation and data acquisition electronics techniques used in free-flight drop model testing at the NASA Langley Research Center. Free-flight drop model testing is a technique for conducting complex aircraft controls research using reduced scale models of experimental aircraft. An introduction to the Free-Flight Drop Model Program is presented first. This is followed by a description of the recently upgraded airborne and ground based instrumentation and data acquisition electronics. Lastly current and future development efforts and opportunities are discussed.

  6. Mass Remaining During Evaporation of Sessile Drop


    to> \\fyj Greek Symbols P Contact angle of sessile drop . n Droplet shape factor = h/d 6 Non-dimensional time = t/i V Air kinematic viscosity...factor n, = h / d (where h = maximum height of the drop ), which can also be directly related to the contact angle (P) of the drop , that is r| = (l-cos(P...three drop size (initial mass or volume) conditions with all other conditions the same. These runs have a constant contact angle , (3 = 16.5° ± 1.5

  7. Rapid Drop Dynamics During Superhydrophobic Condensation

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


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

  8. Numerical simulations of vibrating sessile drop

    Kahouadji, Lyes; Chergui, Jalel; Juric, Damir; Shin, Seungwon; Craster, Richard; Matar, Omar


    A vibrated drop constitutes a very rich physical system, blending both interfacial and volume phenomena. A remarkable experimental study was performed by M. Costalonga highlighting sessile drop motion subject to horizontal, vertical and oblique vibration. Several intriguing phenomena are observed such as drop walking and rapid droplet ejection. We perform three-dimensional direct numerical simulations of vibrating sessile drops where the phenomena described above are computed using the massively parallel multiphase code BLUE. EPSRC UK Programme Grant MEMPHIS (EP/K003976/1).

  9. Impact force of a falling drop

    Soto, Dan; Clanet, Cristophe; Quere, David; Xavier Boutillon Collaboration


    Controlling droplet deposition is crucial in many industrial processes such as spraying pesticides on crops, inkjet printing or spray coating. Therefore, the dynamics of drop impacts have been extensively studied for more than one century. However, few literature describe the impacting force of a drop on a solid flat surface, although it might be a way to measure the size distribution of a collection of falling drops. We investigated experimentally how the instantaneous force at impact depends on impact velocity and drop radius. We also propose a new model to understand our observations. Physique et Mecanique des Milieux Heterogenes, CNRS, ESPCI, Paris France & Ladhyx, CNRS, Ecole Polytechnique, Palaiseau, France.

  10. Drops moving along and across a filament

    Sahu, Rakesh P.; Sinha-Ray, Suman; Yarin, Alexander; Pourdeyhimi, Behnam


    The present work is devoted to the experimental study of oil drop motion both along and across a filament due to the air jet blowing. In case of drop moving along the filament, phenomena such as drop stick-slip motion, shape oscillations, shedding of a tail along the filament, the tail capillary instability and drop recoil motion were observed which were rationalized in the framework of simplified models. Experiments with cross-flow of the surrounding gas relative to the filament with an oil drop on it were conducted, with air velocity in the range of 7.23 to 22.7 m s-1. The Weber number varied from 2 to 40 and the Ohnesorge number varied from 0.07 to 0.8. The lower and upper critical Weber numbers were introduced to distinguish between the beginning of the drop blowing off the filament and the onset of the bag-stamen breakup. The range of the Weber number between these two critical values is filled with three types of vibrational breakup: V1 (a balloon-like drop being blown off), V2 (a drop on a single stamen being blown off), and V3 (a drop on a double stamen being blown off). The Weber number/Ohnesorge number plane was delineated into domains of different breakup regimes. The work is supported by the Nonwovens Cooperative Research Center (NCRC).

  11. Drop deformation by laser-pulse impact

    Gelderblom, Hanneke; Klein, Alexander L; Bouwhuis, Wilco; Lohse, Detlef; Villermaux, Emmanuel; Snoeijer, Jacco H


    A free-falling absorbing liquid drop hit by a nanosecond laser-pulse experiences a strong recoil-pressure kick. As a consequence, the drop propels forward and deforms into a thin sheet which eventually fragments. We study how the drop deformation depends on the pulse shape and drop properties. We first derive the velocity field inside the drop on the timescale of the pressure pulse, when the drop is still spherical. This yields the kinetic-energy partition inside the drop, which precisely measures the deformation rate with respect to the propulsion rate, before surface tension comes into play. On the timescale where surface tension is important the drop has evolved into a thin sheet. Its expansion dynamics is described with a slender-slope model, which uses the impulsive energy-partition as an initial condition. Completed with boundary integral simulations, this two-stage model explains the entire drop dynamics and its dependance on the pulse shape: for a given propulsion, a tightly focused pulse results in a...

  12. Correlation for Sessile Drop Evaporation

    Kelly-Zion, Peter; Pursell, Christopher; Wassom, Gregory; Mandelkorn, Brenton; Nkinthorn, Chris


    To better understand how the evaporation of sessile drops and small puddles is controlled by the vapor phase transport mechanisms of mass diffusion and buoyancy-induced convection, the evaporation rates of eight liquids evaporating under a broad range of ambient conditions were correlated with physical and geometrical properties. Examination of the correlation provides valuable insight into how the roles of diffusive and convective transport change with physical and geometrical parameters. The correlation predicts measured evaporation rates to within a root-mean-square error of 7.3%. The correlation is composed of two terms, a term which provides the rate of evaporation under diffusion-only conditions, and a term which provides the influence of convection. This second term suggests the manner in which the processes of diffusion and convection are coupled. Both processes are dependent on the distribution of the vapor, through the molar concentration gradient for diffusion and through the mass density gradient for convection. The term representing the influence of convection is approximately inversely proportional to the square root of diffusivity, indicating the tendency of diffusive transport to reduce convection by making the vapor distribution more uniform. Financial support was provided by the ACS Petroleum Research Fund.


    LIU Tao; LU Xiyun


    The migration of deformable drops in the channel flow neglecting the gravity influence is investigated numerically by solving the incompressible Navier-Stokes equations using the finitedifference method coupled with the front-tracking technique. The objectives of this study are to examine the effectiveness of the present approach for predicting the migration of drops in a shear flow and to investigate the behavior of the drop migration in the channel flow under zero-gravity. To validate the present calculation, some typical results are compared with available computational and theoretical data, which confirms that the present approach is reliable in predicting the drop migration.With respect to the drop migration in the channel flow at finite Reynolds numbers, the drops either move to an equilibrium lateral position or undergo an oscillatory motion under different conditions.The effects of some typical parameters, e.g., the Reynolds number, the Weber number, the viscosity ratio and the density ratio of the drop fluid to the suspending medium, and the drop size, on the migration of drops are discussed and analyzed.

  14. Biofilm formation over surface patterned with pico-liter oil micro-drop array

    Jalali, Maryam; Sheng, Jian


    It has been suggested that biodegradation by microbes is an effective process in the cleansing of oil polluted marine environments. It has also been speculated that dispersants could further enhance processes amid no direct evidence. The studies in the relevant scales are severely hampered by lack of techniques to generate uniform micro-scale drops allowing in-situ monitoring of these processes. In this paper, we present a microfabrication technique allowing patterning microfluidic surfaces with arrays of micro oil drops. The array of oil drops was printed by micro transfer molding/printing with negative PDMS stamps. The printed micro-drops have dimensions ranging from 5 μm to 50 μm. Non-circular shapes, such as square and triangle, can also be printed and maintained for weeks. Atomic force microscopy is used to characterize the topology and interfacial structures of droplets. The results reveal that although the drop with different base shapes assumes dome like profile asymptotically, donut and top-hat shapes are also observed. Time evolution measurement elucidates that in the absences of inviscid mechanisms in comparison to a micro-liter drop, subtle interplays between interfacial forces and viscosity play crucial role in the shape of pico-liter drop. With the developed surfaces, the effects of oil drop sizes and interfacial structures on biofilm formation are studied and reported.

  15. Drop Axis Ratio Distributions in Stratiform and Convective Rain

    Thurai, M.; Bringi, V. N.; Petersen, W. A.; Schultz, C.


    A fully calibrated low profile 2D video disdrometer (2DVD) has been recording many different rainfall events in Northern Alabama (USA) since June 2007. An earlier publication reported drop shapes and axis ratio distributions determined for some of the events. For one of the cases examined, a noticeable shift in the 3.5 - 3.75 mm drop axis ratio distribution was noted. In this paper, we extend the earlier work by separating the 2DVD measurements into stratiform and convective rain. The separation is made possible by using the minute-by-minute drop size distribution (DSD) measured by the 2DVD. The 1-minute DSDs are fitted to a gamma distribution, and using a simple indexing technique which involves two of the fitted parameters, periods of convective and stratiform rain are separated for a given event. The output of the DSD indexing technique is qualitatively confirmed by comparing with simultaneous time series observations from a co-located UHF profiler which continuously records height profiles of reflectivity, Doppler mean and spectral width, all of which enable the identification of bright-band periods and, furthermore, periods of moderate and deep convection. Excellent consistency is found between the output of the DSD-based separation method and the profiler observations. Next, we utilize the output of DSD index-based separation method to flag the periods of severe convection for a given event. Drop axis ratios during the flagged periods are derived and compared with those during stratiform rain periods. Five cases have been considered. Axis ratio distributions do not show appreciable differences between stratiform and convective periods for four of the cases. The fifth case (the same case as reported earlier) shows a shift in the 3.5 - 3.75 mm drop axis ratios during a prolonged period of convection. The contoured shapes for these drops determined from the 2DVD camera data indicate the possibility of non-axisymmetric oscillations, compared with the contoured

  16. Total Site Heat Integration Considering Pressure Drops

    Kew Hong Chew


    Full Text Available Pressure drop is an important consideration in Total Site Heat Integration (TSHI. This is due to the typically large distances between the different plants and the flow across plant elevations and equipment, including heat exchangers. Failure to consider pressure drop during utility targeting and heat exchanger network (HEN synthesis may, at best, lead to optimistic energy targets, and at worst, an inoperable system if the pumps or compressors cannot overcome the actual pressure drop. Most studies have addressed the pressure drop factor in terms of pumping cost, forbidden matches or allowable pressure drop constraints in the optimisation of HEN. This study looks at the implication of pressure drop in the context of a Total Site. The graphical Pinch-based TSHI methodology is extended to consider the pressure drop factor during the minimum energy requirement (MER targeting stage. The improved methodology provides a more realistic estimation of the MER targets and valuable insights for the implementation of the TSHI design. In the case study, when pressure drop in the steam distribution networks is considered, the heating and cooling duties increase by 14.5% and 4.5%.

  17. Aging, Terminal Decline, and Terminal Drop

    Palmore, Erdman; Cleveland, William


    Data from a 20-year longitudinal study of persons over 60 were analyzed by step-wise multiple regression to test for declines in function with age, for terminal decline (linear relationship to time before death), and for terminal drop (curvilinear relationship to time before death). There were no substantial terminal drop effects. (Author)

  18. Self-Excited Drop Oscillations in Electrowetting

    Baret, Jean-Christophe; Decre, Michel M.J.; Mugele, Frieder


    We studied millimeter-sized aqueous sessile drops in an ambient oil environment in a classical electrowetting configuration with a wire-shaped electrode placed at a variable height above the substrate. Within a certain range of height and above a certain threshold voltage, the drop oscillates period

  19. Static shapes of levitated viscous drops

    Duchemin, L.; Lister, J. R.; Lange, U.


    We consider the levitation of a drop of molten glass above a spherical porous mould, through which air is injected with constant velocity. The glass is assumed to be sufficiently viscous compared to air that motion in the drop is negligible. Thus static equilibrium shapes are determined by the coupling between the lubricating pressure in the supporting air cushion and the Young-Laplace equation. The upper surface of the drop is under constant atmospheric pressure; the static shape of the lower surface of the drop is computed using lubrication theory for the thin air film. Matching of the sessile curvature of the upper surface to the curvature of the mould gives rise to a series of capillary "brim" waves near the edge of the drop which scale with powers of a modified capillary number. Several branches of static solutions are found, such that there are multiple solutions for some drop volumes, but no physically reasonable solutions for other drop volumes. Comparison with experiments and full Navier-Stokes calculations suggests that the stability of the process can be predicted from the solution branches for the static shapes, and related to the persistence of brim waves to the centre of the drop. This suggestion remains to be confirmed by a formal stability analysis.

  20. University Drop-Out: An Italian Experience

    Belloc, Filippo; Maruotti, Antonello; Petrella, Lea


    University students' drop-out is a crucial issue for the universities' efficiency evaluation and funding. In this paper, we analyze the drop-out rate of the Economics and Business faculty of Sapienza University of Rome. We use administrative data on 9,725 undergraduates students enrolled in three-years bachelor programs from 2001 to 2007 and…

  1. Many Drops Make a Lake

    Chaitanya S. Mudgal


    greater knowledge, better skills and disseminate this knowledge through this journal to influence as many physicians and their patients as possible. They have taken the knowledge of their teachers, recognized their giants and are now poised to see further than ever before. My grandmother often used to quote to me a proverb from India, which when translated literally means “Many drops make a lake”. I cannot help but be amazed by the striking similarities between the words of Newton and this Indian saying. Therefore, while it may seem intuitive, I think it must be stated that it is vital for the betterment of all our patients that we recognize our own personal lakes to put our drops of knowledge into. More important is that we recognize that it is incumbent upon each and every one of us to contribute to our collective lakes of knowledge such as ABJS. And finally and perhaps most importantly we need to be utterly cognizant of never letting such lakes of knowledge run dry.... ever.

  2. Apendicectomia pelas técnicas de ligadura simples e de sepultamento sem ligadura do coto apendicular: estudo comparativo em coelhos Appendicectomy using the tie-and-drop and purse-string technique without ligation of appendicular stump: a comparative study in rabbits

    Alfredo Soares Cabral Junior


    Full Text Available OBJETIVO: Comparar as técnicas operatórias de ligadura simples (A e de sepultamento sem ligadura do coto apendicular (B. MÉTODO: Foram utilizados 36 coelhos da linhagem Nova Zelândia, machos, distribuídos aleatoriamente em dois grupos de 18, divididos respectivamente em subgrupos de seis animais cada um e praticada a eutanásia decorrido o tempo pós-operatório de sete, 14 e 21 dias. Foram avaliados macroscopicamente conforme a ferida operatória estivesse limpa, tivessem abscesso ou deiscência e a cavidade abdominal pela presença de aderências peritoneais. Foi feita avaliação histológica pela presença ou ausência dos seguintes parâmetros: infiltrado inflamatório agudo e crônico, fibrose, granuloma de corpo estranho, necrose e integridade da camada mucosa. RESULTADOS: Nos achados macroscópicos não foram observadas diferenças significantes no sétimo, 14º e 21º P.O. quanto à presença de abscesso e deiscência da ferida operatória entre os grupos A e B; o mesmo ocorreu quanto à presença de aderências peritoneais entre alças intestinais. Nos achados microscópicos houve diferença significante no 21º P.O. quanto ao infiltrado inflamatório agudo maior no grupo B, e à integridade da camada mucosa, maior no A. Na contagem de fibras colágenas houve diferença significante no 21º P.O., maior no grupo B. CONCLUSÃO: Do ponto de vista histológico a técnica de ligadura simples é superior à de sepultamento sem ligadura do coto apendicular.BACKGROUND: The purpose of this study was to compare two surgical techniques: tie and drop(A and purse string without ligation of apendicular stump.(B METHOD: The study included 36 young male New Zealand inbred rabbits, randomly distributed into two groups of 18, divided into three subgroups of six each, when eutanasia was done after postoperative periods of 7, 14, and 21 days. The animals were macroscopically evaluated according to the wound presence of abscess or dehiscense, and the

  3. Dynamic Stability of Equilibrium Capillary Drops

    Feldman, William M.; Kim, Inwon C.


    We investigate a model for contact angle motion of quasi-static capillary drops resting on a horizontal plane. We prove global in time existence and long time behavior (convergence to equilibrium) in a class of star-shaped initial data for which we show that topological changes of drops can be ruled out for all times. Our result applies to any drop which is initially star-shaped with respect to a small ball inside the drop, given that the volume of the drop is sufficiently large. For the analysis, we combine geometric arguments based on the moving-plane type method with energy dissipation methods based on the formal gradient flow structure of the problem.

  4. CPAS Preflight Drop Test Analysis Process

    Englert, Megan E.; Bledsoe, Kristin J.; Romero, Leah M.


    Throughout the Capsule Parachute Assembly System (CPAS) drop test program, the CPAS Analysis Team has developed a simulation and analysis process to support drop test planning and execution. This process includes multiple phases focused on developing test simulations and communicating results to all groups involved in the drop test. CPAS Engineering Development Unit (EDU) series drop test planning begins with the development of a basic operational concept for each test. Trajectory simulation tools include the Flight Analysis and Simulation Tool (FAST) for single bodies, and the Automatic Dynamic Analysis of Mechanical Systems (ADAMS) simulation for the mated vehicle. Results are communicated to the team at the Test Configuration Review (TCR) and Test Readiness Review (TRR), as well as at Analysis Integrated Product Team (IPT) meetings in earlier and intermediate phases of the pre-test planning. The ability to plan and communicate efficiently with rapidly changing objectives and tight schedule constraints is a necessity for safe and successful drop tests.

  5. Temperature Effect on Photovoltaic Modules Power Drop

    Qais Mohammed Aish


    Full Text Available In order to determine what type of photovoltaic solar module could best be used in a thermoelectric photovoltaic power generation. Changing in powers due to higher temperatures (25oC, 35oC, and 45oC have been done for three types of solar modules: monocrystalline , polycrystalline, and copper indium gallium (di selenide (CIGS. The Prova 200 solar panel analyzer is used for the professional testing of three solar modules at different ambient temperatures; 25oC, 35oC, and 45oC and solar radiation range 100-1000 W/m2. Copper indium gallium (di selenide module has the lowest power drop (with the average percentage power drop 0.38%/oC while monocrystalline module has the highest power drop (with the average percentage power drop 0.54%/oC, while polycrystalline module has a percentage power drop of 0.49%/oC.

  6. Pressure drop in CIM disk monolithic columns.

    Mihelic, Igor; Nemec, Damjan; Podgornik, Ales; Koloini, Tine


    Pressure drop analysis in commercial CIM disk monolithic columns is presented. Experimental measurements of pressure drop are compared to hydrodynamic models usually employed for prediction of pressure drop in packed beds, e.g. free surface model and capillary model applying hydraulic radius concept. However, the comparison between pressure drop in monolith and adequate packed bed give unexpected results. Pressure drop in a CIM disk monolithic column is approximately 50% lower than in an adequate packed bed of spheres having the same hydraulic radius as CIM disk monolith; meaning they both have the same porosity and the same specific surface area. This phenomenon seems to be a consequence of the monolithic porous structure which is quite different in terms of the pore size distribution and parallel pore nonuniformity compared to the one in conventional packed beds. The number of self-similar levels for the CIM monoliths was estimated to be between 1.03 and 2.75.

  7. Universality in freezing of an asymmetric drop

    Ismail, Md Farhad; Waghmare, Prashant R.


    We present the evidence of universality in conical tip formation during the freezing of arbitrary-shaped sessile droplets. The focus is to demonstrate the relationship between this universality and the liquid drop shape. We observe that, in the case of asymmetric drops, this universal shape is achieved when the tip reconfigures by changing its location, which subsequently alters the frozen drop shape. The proposed "two-triangle" model quantifies the change in the tip configuration as a function of the asymmetry of the drop that shows a good agreement with the experimental evidence. Finally, based on the experimental and theoretical exercise, we propose the scaling dependence between the variations in the tip configuration and the asymmetry of the drop.

  8. Patients dropping out of treatment in Italy.

    Morlino, M; Martucci, G; Musella, V; Bolzan, M; de Girolamo, G


    The aim of this study was to explore the extent and the specific features of drop-out for patients having a first contact with an university psychiatric outpatient clinic in Italy over the course of 1 year and to determine which variables were associated with early termination of treatment. Of the 158 patients selected for this study, there was an overall 3-month drop-out rate following the first visit of 63%. Of the 59 patients who had returned once after the initial contact, 28 interrupted subsequently the treatment, although the therapist's plan included further visits. The overall drop-out rate at 3 months was thus 82%. The only 2 variables associated with drop-out rates were the patients' perception of the severity of their disorder and the psychiatric history: continuing patients were more frequently in agreement with the clinician's judgment as compared with those who dropped out and were more likely to have already been in psychiatric treatment.

  9. Finite Element Analysis of the Effect on Edge Distance of the Tensile Bearing Capacity of Embedded Hanging Parts

    Meng Xian Hong


    Full Text Available In order to explore the trend of tensile bearing capacity of embedded hanging parts when change the edge distance. Based on the finite element analysis software ABAQUS, the four simulation model was established. The buried depth and strength of concrete remain unchanged, but the edge distance was gradient change. By the load - displacement curve of every model known, the greater the edge distance, the greater the bearing capacity. When the edge distance reaches 1.5 times buried depth, the effect of increasing edge distance for improving the bearing capacity will be impaired.

  10. Techniques for Teachers Section

    Tait, A., Ed.


    Includes a simple technique to demonstrate Millikan's oil drop experiment, an environmental studies experiment to measure dissolved oxygen in water samples, and a technique to demonstrate action-reaction. Science materials described are the Pol-A-Star Tomiscope, Nuffield chemistry film loops, air pucks and pH meters. (JR)

  11. Condensation on surface energy gradient shifts drop size distribution toward small drops.

    Macner, Ashley M; Daniel, Susan; Steen, Paul H


    During dropwise condensation from vapor onto a cooled surface, distributions of drops evolve by nucleation, growth, and coalescence. Drop surface coverage dictates the heat transfer characteristics and depends on both drop size and number of drops present on the surface at any given time. Thus, manipulating drop distributions is crucial to maximizing heat transfer. On earth, manipulation is achieved with gravity. However, in applications with small length scales or in low gravity environments, other methods of removal, such as a surface energy gradient, are required. This study examines how chemical modification of a cooled surface affects drop growth and coalescence, which in turn influences how a population of drops evolves. Steam is condensed onto a horizontally oriented surface that has been treated by silanization to deliver either a spatially uniform contact angle (hydrophilic, hydrophobic) or a continuous radial gradient of contact angles (hydrophobic to hydrophilic). The time evolution of number density and associated drop size distributions are measured. For a uniform surface, the shape of the drop size distribution is unique and can be used to identify the progress of condensation. In contrast, the drop size distribution for a gradient surface, relative to a uniform surface, shifts toward a population of small drops. The frequent sweeping of drops truncates maturation of the first generation of large drops and locks the distribution shape at the initial distribution. The absence of a shape change indicates that dropwise condensation has reached a steady state. Previous reports of heat transfer enhancement on chemical gradient surfaces can be explained by this shift toward smaller drops, from which the high heat transfer coefficients in dropwise condensation are attributed to. Terrestrial applications using gravity as the primary removal mechanism also stand to benefit from inclusion of gradient surfaces because the critical threshold size required for

  12. Kinetic asymmetries between forward and drop jump landing tasks

    Morgana Alves de Britto


    Full Text Available Landing asymmetry is a risk factor for knee anterior cruciate ligament injury. The aim of this study was to identify kinetic asymmetries in healthy recreational athletes performing different jump-landing techniques. Twelve recreational athletes engaged in regular training underwent kinetic evaluation using two 3D force plates and were analyzed for: (a three-dimensional peak forces, (b time to peak vertical force, and (c initial phase asymmetries. All data were collected during performance of unilateral and bilateral trials of forward and drop jump tasks. Forward jump-landing tasks elicited greater kinetic asymmetry than drop-landing tasks. Regardless of jump-landing technique, the preferred leg experienced higher forces than the non-preferred leg. The initial landing phase showed more kinetic asymmetries than the later phase when peak vertical forces occur. It was concluded that when screening athletes for kinetic asymmetries that may predispose them to injury, forward jump-landing tasks and the early landing phase might show more kinetic asymmetries than drop jump-landing tasks and the late landing phase, respectively.

  13. The Drop Tower Bremen -An Overview

    von Kampen, Peter; Könemann, Thorben; Rath, Hans J.

    The Center of Applied Space Technology and Microgravity (ZARM) was founded in 1985 as an institute of the University of Bremen, which focuses on research on gravitational and space-related phenomena. In 1988, the construction of ZARM`s drop tower began. Since its inau-guration in September 1990, the eye-catching Drop Tower Bremen with a height of 146m and its characteristic glass roof has become twice a landmark on the campus of the University of Bremen and the emblem of the technology park Bremen. As such an outstanding symbol of space science in Bremen the drop tower provides an european unique facility for experiments under conditions of high-quality weightlessness with residual gravitational accelerations in the microgravity regime. The period of maximum 4.74s of each freely falling experiment at the Drop Tower Bremen is only limited by the height of the drop tower vacuum tube, which was fully manufactured of steal and enclosed by an outer concrete shell. Thus, the pure free fall height of each microgravity drop experiment is approximately 110m. By using the later in-stalled catapult system established in 2004 ZARM`s short-term microgravity laboratory is able to nearly double the time of free fall. This world-wide inimitable capsule catapult system meets scientists` demand of extending the period of weightlessness. During the catapult operation the experiment capsule performs a vertical parabolic flight within the drop tower vacuum tube. In this way the time of microgravity can be extended to slightly over 9s. Either in the drop or in the catapult operation routine the repetition rates of microgravity experiments at ZARM`s drop tower facility are the same, generally up to 3 times per day. In comparison to orbital platforms the ground-based laboratory Drop Tower Bremen represents an economic alternative with a permanent access to weightlessness on earth. Moreover, the exceptional high quality of weightlessness in order of 1e-6 g (in the frequency range below 100

  14. Leidenfrost drops on a heated liquid pool

    Maquet, Laurent; Darbois-Texier, Baptiste; Brandenbourger, Martin; Rednikov, Alexey; Colinet, Pierre; Dorbolo, Stéphane


    We show that a volatile liquid drop placed at the surface of a non-volatile liquid pool warmer than the boiling point of the drop can experience a Leidenfrost effect even for vanishingly small superheats. Such an observation points to the importance of the substrate roughness, negligible in the case considered here, in determining the threshold Leidenfrost temperature. A theoretical model based on the one proposed by Sobac et al. [Phys. Rev. E 90, 053011 (2014)] is developed in order to rationalize the experimental data. The shapes of the drop and of the substrate are analyzed. The model notably provides scalings for the vapor film thickness. For small drops, these scalings appear to be identical to the case of a Leidenfrost drop on a solid substrate. For large drops, in contrast, they are different and no evidence of chimney formation has been observed either experimentally or theoretically in the range of drop sizes considered in this study. Concerning the evaporation dynamics, the radius is shown to decrea...

  15. Interaction of Drops on a Soft Substrate

    Lubbers, Luuk A.; Weijs, Joost H.; Das, Siddhartha; Botto, Lorenzo; Andreotti, Bruno; Snoeijer, Jacco H.


    A sessile drop can elastically deform a substrate by the action of capillary forces. The typical size of the deformation is given by the ratio of surface tension and the elastic modulus, γ / E , which can reach up to 10-100 microns for soft elastomers. In this talk we theoretically show that the contact angles of drops on such a surface exhibit two transitions when increasing γ / E : (i) the microsocopic geometry of the contact line first develops a Neumann-like cusp when γ / E is of the order of few nanometers, (ii) the macroscopic angle of the drop is altered only when γ / E reaches the size of the drop. Using the same framework we then show that two neighboring drops exhibit an effective interaction, mediated by the deformation of the elastic medium. This is in analogy to the well-known Cheerios effect, where small particles at a liquid interface attract eachother due to the meniscus deformations. Here we reveal the nature of drop-drop interactions on a soft substrate by combining numerical and analytical calculations.

  16. Drop impact splashing and air entrapment

    Thoraval, Marie-Jean


    Drop impact is a canonical problem in fluid mechanics, with numerous applications in industrial as well as natural phenomena. The extremely simple initial configuration of the experiment can produce a very large variety of fast and complex dynamics. Scientific progress was made in parallel with major improvements in imaging and computational technologies. Most recently, high-speed imaging video cameras have opened the exploration of new phenomena occurring at the micro-second scale, and parallel computing allowed realistic direct numerical simulations of drop impacts. We combine these tools to bring a new understanding of two fundamental aspects of drop impacts: splashing and air entrapment. The early dynamics of a drop impacting on a liquid pool at high velocity produces an ejecta sheet, emerging horizontally in the neck between the drop and the pool. We show how the interaction of this thin liquid sheet with the air, the drop or the pool, can produce micro-droplets and bubble rings. Then we detail how the breakup of the air film stretched between the drop and the pool for lower impact velocities can produce a myriad of micro-bubbles.

  17. Conically shaped drops in electric fields

    Stone, Howard A.; Brenner, Michael P.; Lister, John R.


    When an electric field is applied to a dielectric liquid containing a suspended immiscible fluid drop, the drop deforms into a prolate ellipsoidal shape. Above a critical field strength the drop develops conical ends, as first observed by Zeleny [Phys. Rev. 10, 1 (1917)] and Wilson & Taylor [Proc. Camb. Phil. Soc. 22, 728 (1925)] for, respectively, the case of conducting drops and soap films in air. The case of two dielectric liquids was studied recently using a slender drop approximation by Li, Halsey & Lobkovsky [Europhys. Lett 27, 575 (1994)]. In this presentation we further develop the slender body approximation to obtain coupled ordinary differential equations for the electric field and the drop shape. Analytical formulae are derived which approximately give the cone angle as a function of the dielectric constant ratio between the two fluids, and the minimum applied electric field at which conical tips first form as a function of the dielectric constant ratio. Finally, drops shapes are calculated numerically and compared with the common prolate shape assumption.

  18. Vibration-induced drop atomization and bursting

    James, A. J.; Vukasinovic, B.; Smith, Marc K.; Glezer, A.


    A liquid drop placed on a vibrating diaphragm will burst into a fine spray of smaller secondary droplets if it is driven at the proper frequency and amplitude. The process begins when capillary waves appear on the free surface of the drop and then grow in amplitude and complexity as the acceleration amplitude of the diaphragm is slowly increased from zero. When the acceleration of the diaphragm rises above a well-defined critical value, small secondary droplets begin to be ejected from the free-surface wave crests. Then, quite suddenly, the entire volume of the drop is ejected from the vibrating diaphragm in the form of a spray. This event is the result of an interaction between the fluid dynamical process of droplet ejection and the vibrational dynamics of the diaphragm. During droplet ejection, the effective mass of the drop diaphragm system decreases and the resonance frequency of the system increases. If the initial forcing frequency is above the resonance frequency of the system, droplet ejection causes the system to move closer to resonance, which in turn causes more vigorous vibration and faster droplet ejection. This ultimately leads to drop bursting. In this paper, the basic phenomenon of vibration-induced drop atomization and drop bursting will be introduced, demonstrated, and characterized. Experimental results and a simple mathematical model of the process will be presented and used to explain the basic physics of the system.

  19. Terminal Effect of Drop Coalescence on Single Drop Mass Transfer Measurements and Its Minimization


    For the mass transfer to single drops during the stage of steady buoyancy-driven motion, experimental measurement is complicated with the terminal effect of additional mass transfer during drop formation and coa lescence at the drop collector. Analysis reveals that consistent operating conditions and experimental procedure are of critical significance for minimizing the terminal effect of drop coalescence on the accuracy of mass transfer measurements. The novel design of a totally-closed extraction column is proposed for this purpose, which guaran tees that the volumetric rate of drop phase injection is exactly equal to that of withdrawal of drops. Tests in two extraction systems demonstrate that the experimental repeatability is improved greatly and the terminal effect of mass transfer during drop coalescence is brought well under control.

  20. Laplacian drop shapes and effect of random perturbations on accuracy of surface tension measurement for different drop constellations.

    Saad, Sameh M I; Neumann, A Wilhelm


    Theoretical drop shapes are calculated for three drop constellations: pendant drops, constrained sessile drops, and unconstrained sessile drops. Based on total Gaussian curvature, shape parameter and critical shape parameter are discussed as a function of different drop sizes and surface tensions. The shape parameter is linked to physical parameters for every drop constellation. The as yet unavailable detailed dimensional analysis for the unconstrained sessile drop is presented. Results show that the unconstrained sessile drop shape depends on a dimensionless volume term and the contact angle. Random perturbations are introduced and the accuracy of surface tension measurement is assessed for precise and perturbed profiles of the three drop constellations. It is concluded that pendant drops are the best method for accurate surface tension measurement, followed by constrained sessile drops. The unconstrained sessile drops come last because they tend to be more spherical at low and moderate contact angles. Of course, unconstrained sessile drops are the only option if contact angles are to be measured.

  1. Quantitative testing of robustness on superomniphobic surfaces by drop impact.

    Nguyen, Thi Phuong Nhung; Brunet, Philippe; Coffinier, Yannick; Boukherroub, Rabah


    The quality of a liquid-repellent surface is quantified by both the apparent contact angle θ(0) that a sessile drop adopts on it and the value of the liquid pressure threshold the surface can withstand without being impaled by the liquid, hence maintaining a low-friction condition. We designed surfaces covered with nanowires obtained by the vapor-liquid-solid (VLS) growth technique that are able to repel most of the existing nonpolar liquids including those with very low surface tension as well as many polar liquids with moderate to high surface tension. These superomniphobic surfaces exhibit apparent contact angles ranging from 125 to 160° depending on the liquid. We tested the robustness of the surfaces against impalement by carrying out drop impact experiments. Our results show how this robustness depends on Young's contact angle θ(0) related to the surface tension of the liquid and that the orientational growth of nanowires is a favorable factor for robustness.

  2. Finite amplitude effects on drop levitation for material properties measurement

    Ansari Hosseinzadeh, Vahideh; Holt, R. Glynn


    The method of exciting shape oscillation of drops to extract material properties has a long history, which is most often coupled with the technique of acoustic levitation to achieve non-contact manipulation of the drop sample. We revisit this method with application to the inference of bulk shear viscosity and surface tension. The literature is replete with references to a "10% oscillation amplitude" as a sufficient condition for the application of Lamb's analytical expressions for the shape oscillations of viscous liquids. Our results show that even a 10% oscillation amplitude leads to dynamic effects which render Lamb's results inapplicable. By comparison with samples of known viscosity and surface tension, we illustrate the complicating finite-amplitude effects (mode-splitting and excess dissipation associated with vorticity) that can occur and then show that sufficiently small oscillations allow us to recover the correct material properties using Lamb's formula.

  3. Detection and Defense Against Packet Drop Attack in MANET

    Tariq Ahamad


    Full Text Available MANET is a temporary network for a specified work and with the enormous growth MANETs it is becoming important and simultaneously challenging to protect this network from attacks and other threats. Packet drop attack or gray hole attack is the easiest way to make a denial of service in these dynamic networks. In this attack the malicious node reflects itself as the shortest path and receives all the packets and drops the selected packets in order to give the user the service that that is not correct. It is a specific kind of attack and protects the network and user from detecting this malicious activity. In this article I have proposed an efficient for step technique that confirms that this attack can be detected and defended with least efforts and resource consumption.

  4. Morphological Transitions of Sliding Drops -- Dynamics and Bifurcations

    Engelnkemper, Sebastian; Gurevich, Svetlana V; Thiele, Uwe


    We study fully three-dimensional droplets that slide down an incline employing a thin-film equation that accounts for capillarity, wettability and a lateral driving force in small-gradient (or long-wave) approximation. In particular, we focus on qualitative changes in the morphology and behavior of stationary sliding drops. We employ the inclination angle of the substrate as control parameter and use continuation techniques to analyze for several fixed droplet sizes the bifurcation diagram of stationary droplets, their linear stability and relevant eigenmodes. The obtained predictions on existence ranges and instabilities are tested via direct numerical simulations that are also used to investigate a branch of time-periodic behavior (corresponding to pearling-coalescence cycles) which emerges at a global instability, the related hysteresis in behavior and a period-doubling cascade. The non-trivial oscillatory behavior close to a Hopf bifurcation of drops with a finite-length tail is also studied. Finally, it ...

  5. Nanofluid Drop Evaporation: Experiment, Theory, and Modeling

    Gerken, William James

    Nanofluids, stable colloidal suspensions of nanoparticles in a base fluid, have potential applications in the heat transfer, combustion and propulsion, manufacturing, and medical fields. Experiments were conducted to determine the evaporation rate of room temperature, millimeter-sized pendant drops of ethanol laden with varying amounts (0-3% by weight) of 40-60 nm aluminum nanoparticles (nAl). Time-resolved high-resolution drop images were collected for the determination of early-time evaporation rate (D2/D 02 > 0.75), shown to exhibit D-square law behavior, and surface tension. Results show an asymptotic decrease in pendant drop evaporation rate with increasing nAl loading. The evaporation rate decreases by approximately 15% at around 1% to 3% nAl loading relative to the evaporation rate of pure ethanol. Surface tension was observed to be unaffected by nAl loading up to 3% by weight. A model was developed to describe the evaporation of the nanofluid pendant drops based on D-square law analysis for the gas domain and a description of the reduction in liquid fraction available for evaporation due to nanoparticle agglomerate packing near the evaporating drop surface. Model predictions are in relatively good agreement with experiment, within a few percent of measured nanofluid pendant drop evaporation rate. The evaporation of pinned nanofluid sessile drops was also considered via modeling. It was found that the same mechanism for nanofluid evaporation rate reduction used to explain pendant drops could be used for sessile drops. That mechanism is a reduction in evaporation rate due to a reduction in available ethanol for evaporation at the drop surface caused by the packing of nanoparticle agglomerates near the drop surface. Comparisons of the present modeling predictions with sessile drop evaporation rate measurements reported for nAl/ethanol nanofluids by Sefiane and Bennacer [11] are in fairly good agreement. Portions of this abstract previously appeared as: W. J

  6. Deviation of viscous drops at chemical steps

    Semprebon, Ciro; Filippi, Daniele; Perlini, Luca; Pierno, Matteo; Brinkmann, Martin; Mistura, Giampaolo


    We present systematic wetting experiments and numerical simulations of gravity driven liquid drops sliding on a plane substrate decorated with a linear chemical step. Surprisingly, the optimal direction to observe crossing is not the one perpendicular to the step, but a finite angle that depends on the material parameters. We computed the landscapes of the force acting on the drop by means of a contact line mobility model showing that contact angle hysteresis dominates the dynamics at the step and determines whether the drop passes onto the lower substrate. This analysis is very well supported by the experimental dynamic phase diagram in terms of pinning, crossing, sliding and sliding followed by pinning.

  7. New Hydrodynamic Mechanism for Drop Coarsening

    Nikolayev, Vadim; Guenoun, Patrick


    We discuss a new mechanism of drop coarsening due to coalescence only, which describes the late stages of phase separation in fluids. Depending on the volume fraction of the minority phase, we identify two different regimes of growth, where the drops are interconnected and their characteristic size grows linearly with time, and where the spherical drops are disconnected and the growth follows (time) 1/3. The transition between the two regimes is sharp and occurs at a well defined volume fraction of order 30%.

  8. On the Deepwater Horizon drop size distributions

    Ryerson, T. B.; Atlas, E. L.; Blake, D. R.; De Gouw, J. A.; Warneke, C.; Peischl, J.; Brock, C. A.; McKeen, S. A.


    Model simulations of the fate of gas and oil released following the Deepwater Horizon blowout in 2012 depend critically on the assumed drop size distributions. We use direct observations of surfacing time, surfacing location, and atmospheric chemical composition to infer an average drop size distribution for June 10, 2012, providing robust first-order constraints on parameterizations in models. We compare the inferred drop size distribution to published work on Deepwater Horizon and discuss the ability of this approach to determine the efficacy of subsurface dispersant injection.

  9. Measurement of force to obstruct the cervical arteries and distribution of tension exerted on a ligature in hanging.

    Yamasaki, Shigeru; Takase, Izumi; Takada, Naoki; Nishi, Katsuji


    We experienced suicidal hanging cases without a ligature in front of the neck. We conducted several anatomical autopsies and the magnetic resonance imaging (MRI), and studied the dynamics behind hanging by applying an apparatus to cadaver and creating a dummy. MRI revealed that the vertebral artery protrudes diagonally upward from the second vertebra to the first one. We also found that this area was not covered with any bony tissue. The average length between the first and second transverse processes was 2 cm. We measured the minimum required force to obstruct the blood stream in both carotid and vertebral arteries exerting 130 mmHg. The required force was 6 kg for the carotid artery and 7 kg for the vertebral artery. Compared to the reported cases, there was not a significant difference in the force to obstruct the carotid artery, however, that of the vertebral artery was lower than the force reported so far. With an experiment of pressure sensitive plastic-sheet, we learned the lateral sides of the neck are compressed more. The results obtained from this study show that the complete and fatal obstruction of the carotid and the vertebral arteries may easily occur when the ligature transects at the lower part of mandible angle.

  10. Aspiration of biological viscoelastic drops

    Guevorkian, Karine; Durth, Mélanie; Dufour, Sylvie; Brochard-Wyart, Françoise


    Spherical cellular aggregates are in vitro systems to study the physical and biophysical properties of tissues. We present a novel approach to characterize the mechanical properties of cellular aggregates using micropipette aspiration technique. We observe an aspiration in two distinct regimes, a fast elastic deformation followed by a viscous flow. We develop a model based on this viscoelastic behavior to deduce the surface tension, viscosity, and elastic modulus. A major result is the increase of the surface tension with the applied force, interpreted as an effect of cellular mechanosensing.

  11. Resistive method for measuring the disintegration speed of Prince Rupert's drops

    Gusenkova, Daria; Glushkov, Evgenii; Zotova, Julia; Zhabin, S N


    We have successfully applied the resistance grid technique to measure the disintegration speed in special type of glass objects, widely known as Prince Rupert's drops. We use a digital oscilloscope and a simple electrical circuit, glued to the surface of the drops, to detect the voltage changes, corresponding to the breaks in the specific parts of the drops. The results obtained using this method are in good qualitative and quantitative agreement with theoretical predictions and previously published data. Moreover, the proposed experimental setup doesn't include any expensive equipment (such as a high-speed camera) and can therefore be widely used in high schools and universities.

  12. Resistive method for measuring the disintegration speed of Prince Rupert's drops

    Bochkov, Mark; Gusenkova, Daria; Glushkov, Evgenii; Zotova, Julia; Zhabin, S. N.


    We have successfully applied the resistance grid technique to measure the disintegration speed in a special type of glass objects, widely known as Prince Rupert's drops. We use a fast digital oscilloscope and a simple electrical circuit, glued to the surface of the drops, to detect the voltage changes, corresponding to the breaks in the specific parts of the drops. The results obtained using this method are in good qualitative and quantitative agreement with theoretical predictions and previously published data. Moreover, the proposed experimental setup does not include any expensive equipment (such as a high-speed camera) and can therefore be widely used in high schools and universities.

  13. Spreading of liquid drops over porous substrates.

    Starov, V M; Zhdanov, S A; Kosvintsev, S R; Sobolev, V D; Velarde, M G


    The spreading of small liquid drops over thin and thick porous layers (dry or saturated with the same liquid) has been investigated in the case of both complete wetting (silicone oils of different viscosities) and partial wetting (aqueous SDS solutions of different concentrations). Nitrocellulose membranes of different porosity and different average pore size have been used as a model of thin porous layers, glass and metal filters have been used as a model of thick porous substrates. The first problem under investigation has been the spreading of small liquid drops over thin porous layers saturated with the same liquid. An evolution equation describing the drop spreading has been deduced, which showed that both an effective lubrication and the liquid exchange between the drop and the porous substrates are equally important. Spreading of silicone oils over different nitrocellulose microfiltration membranes was carried out. The experimental laws of the radius of spreading on time confirmed the theory predictions. The spreading of small liquid drops over thin dry porous layers has also been investigated from both theoretical and experimental points of view. The drop motion over a dry porous layer appears caused by the interplay of two processes: (a). the spreading of the drop over already saturated parts of the porous layer, which results in a growth of the drop base, and (b). the imbibition of the liquid from the drop into the porous substrate, which results in a shrinkage of the drop base and a growth of the wetted region inside the porous layer. As a result of these two competing processes the radius of the drop base goes through a maximum as time proceeds. A system of two differential equations has been derived to describe the time evolution of the radii of both the drop base and the wetted region inside the porous layer. This system includes two parameters, one accounts for the effective lubrication coefficient of the liquid over the wetted porous substrate, and

  14. Electric field induced deformation of sessile drops

    Corson, Lindsey; Tsakonas, Costas; Duffy, Brian; Mottram, Nigel; Brown, Carl; Wilson, Stephen


    The ability to control the shape of a drop with the application of an electric field has been exploited for many technological applications including measuring surface tension, producing an optical display device, and optimising the optical properties of microlenses. In this work we consider, both theoretically and experimentally, the deformation of pinned sessile drops with contact angles close to either 0° or 90° resting on the lower substrate inside a parallel plate capacitor due to an A.C. electric field. Using both asymptotic and numerical approaches we obtain predictive equations for the static and dynamic drop shape deformations as functions of the key experimental parameters (drop size, capacitor plate separation, electric field magnitude and contact angle). The asymptotic results agree well with the experimental results for a range of liquids. We gratefully acknowledge the financial support of EPSRC via research Grants EP/J009865 and EP/J009873.

  15. How to Use Nose Drops Properly

    ... Use nose drops only as long as directed Store medications out of reach of children Copyright 2013, American Society of Health-System Pharmacists. All rights reserved. This material may not be reproduced, displayed, modified, or distributed ...

  16. How to Use Eye Drops Properly

    ... doses Use the exact number of drops recommended Store medications out of reach of children Copyright 2013, American Society of Health-System Pharmacists. All rights reserved. This material may not be reproduced, displayed, modified, or distributed ...

  17. Drop impact of shear thickening liquids

    Boyer, Francois; Dijksman, J Frits; Lohse, Detlef


    The impact of drops of concentrated non-Brownian suspensions (cornstarch and polystyrene spheres) onto a solid surface is investigated experimentally. The spreading dynamics and maxi- mal deformation of the droplet of such shear thickening liquids are found to be markedly different from the impact of Newtonian drops. A particularly striking observation is that the maximal de- formation is independent of the drop velocity and that the deformation suddenly stops during the impact phase. Both observations are due to the shear-thickening rheology of the suspensions, as is theoretically explained from a balance between the kinetic energy and the viscously-dissipated en- ergy, from which we establish a scaling relation between drop maximal deformation and rheological parameters of concentrated suspensions.

  18. Micro-splashing by drop impacts

    Thoroddsen, Sigurdur T.


    We use ultra-high-speed video imaging to observe directly the earliest onset of prompt splashing when a drop impacts onto a smooth solid surface. We capture the start of the ejecta sheet travelling along the solid substrate and show how it breaks up immediately upon emergence from the underneath the drop. The resulting micro-droplets are much smaller and faster than previously reported and may have gone unobserved owing to their very small size and rapid ejection velocities, which approach 100 m s-1, for typical impact conditions of large rain drops. We propose a phenomenological mechanism which predicts the velocity and size distribution of the resulting microdroplets. We also observe azimuthal undulations which may help promote the earliest breakup of the ejecta. This instability occurs in the cusp in the free surface where the drop surface meets the radially ejected liquid sheet. © 2012 Cambridge University Press.

  19. The sessile drop method for immunohistochemical processing of unmounted sections of nervous tissue.

    Nadelhaft, I


    A novel method for the immunohistochemical processing of free-floating tissue sections is described. Sections are immersed within drops of solution arranged on a hydrophobic surface. The procedure consists of sequentially suctioning away one fluid drop and replacing it by another, while the section remains in place. The technique permits easy testing of different antiserum dilutions, comparisons among different immunohistochemical protocols, and comparison of different antisera on serial tissue sections. Comparison is made to processing mounted sections.

  20. Fluid Flower : Microliquid Patterning via Drop Impact

    Lee, Minhee


    In microfluidic technologies, direct patterning of liquid without resorting to micromachined solid structures has various advantages including reduction of the frictional dissipation and the fabrication cost. This fluid dynamics video illustrates the method to micropattern a liquid on a solid surface with drop impact. We experimentally show that a water drop impacting with the wettability-patterned solid retracts fast on the hydrophobic regions while being arrested on the hydrophilic areas.

  1. Blood drop patterns: Formation and applications.

    Chen, Ruoyang; Zhang, Liyuan; Zang, Duyang; Shen, Wei


    The drying of a drop of blood or plasma on a solid substrate leads to the formation of interesting and complex patterns. Inter- and intra-cellular and macromolecular interactions in the drying plasma or blood drop are responsible for the final morphologies of the dried patterns. Changes in these cellular and macromolecular components in blood caused by diseases have been suspected to cause changes in the dried drop patterns of plasma and whole blood, which could be used as simple diagnostic tools to identify the health of humans and livestock. However, complex physicochemical driving forces involved in the pattern formation are not fully understood. This review focuses on the scientific development in microscopic observations and pattern interpretation of dried plasma and whole blood samples, as well as the diagnostic applications of pattern analysis. Dried drop patterns of plasma consist of intricate visible cracks in the outer region and fine structures in the central region, which are mainly influenced by the presence and concentration of inorganic salts and proteins during drying. The shrinkage of macromolecular gel and its adhesion to the substrate surface have been thought to be responsible for the formation of the cracks. Dried drop patterns of whole blood have three characteristic zones; their formation as functions of drying time has been reported in the literature. Some research works have applied engineering treatment to the evaporation process of whole blood samples. The sensitivities of the resultant patterns to the relative humidity of the environment, the wettability of the substrates, and the size of the drop have been reported. These research works shed light on the mechanisms of spreading, evaporation, gelation, and crack formation of the blood drops on solid substrates, as well as on the potential applications of dried drop patterns of plasma and whole blood in diagnosis.

  2. Drop Performance Test of CRDMs for JRTR

    Choi, Myoung-Hwan; Cho, Yeong-Garp; Chung, Jong-Ha [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Jung-Hyun [POSCO Plandtec Co. Ltd, Ulsan (Korea, Republic of); Lee, Kwan-Hee [RIST, Pohang (Korea, Republic of)


    The drop test results of CRDMs with AC-type electromagnet show that the initial delay times are not satisfied with the requirement, 0.15 seconds. After the replacement of the electromagnet from AC-type to DCtype, the drop times of CARs and accelerations due to the impact of moving parts are satisfied with all requirements. As a result, it is found that four CRDMs to be installed at site have a good drop performance, and meet all performance requirements. A control rod drive mechanism (CRDM) is a device to control the position of a control absorber rod (CAR) in the core by using a stepping motor which is commanded by the reactor regulating system (RRS) to control the reactivity during the normal operation of the reactor. The top-mounted CRDM driven by the stepping motor for Jordan Research and Training Reactor (JRTR) has been developed in KAERI. The CRDM for JRTR has been optimized by the design improvement based on that of the HANARO. It is necessary to verify the performances such as the stepping, drop, endurance, vibration, seismic and structural integrity for active components. Especially, the CAR drop curves are important data for the safety analysis. This paper describes the test results to demonstrate the drop performances of a prototype and 4 CRDMs to be installed at site. The tests are carried out at a test rig simulating the actual reactor's conditions.

  3. Transition Mode Shapes in a Vibrating Drop

    Vukasinovic, Bojan; Smith, Marc K.; Glezer, Ari


    Vertical, time-periodic vibration of a diaphragm has been used to atomize a primary sessile drop into a fine spray of secondary droplets. The evolution and rate of atomization depend on the coupled dynamics of the sessile drop and the piezoelectrically-driven, low-mass diaphragm. The evolution of the free surface of the drop is characterized by the appearance of a hierarchy of surface waves that we investigated using high-speed imaging and laser vibrometry. At low-driving amplitudes, we see the appearance of time-harmonic axisymmetric waves on the drop's free surface induced by the motion of the contact line. As the vibration amplitude increases, azimuthal waves at the subharmonic of the forcing frequency appear around the periphery of the drop and propagate towards its center. A striking lattice mode emerges upon the breakdown of the axisymmetric wave pattern, followed by the appearance of the highly-agitated free surface of the pre-ejection mode shape. Subsequent to the breakdown of the lattice structure, the frequency of the most energetic mode is a subharmonic of the driving frequency. The complex interaction of the fundamental and subharmonic waves ultimately leads to the breakdown of the free surface and the atomization of the drop.

  4. Analysis of user characteristics related to drop-off detection with long cane

    Dae Shik Kim, PhD


    Full Text Available This study examined how user characteristics affect drop-off detection with the long cane. A mixed-measures design with block randomization was used for the study, in which 32 visually impaired adults attempted to detect the drop-offs using different cane techniques. Younger cane users detected drop-offs significantly more reliably (mean +/- standard deviation = 74.2% +/- 11.2% of the time than older cane users (60.9% +/- 10.8%, p = 0.009. The drop-off detection threshold of the younger participants (5.2 +/- 2.1 cm was also statistically significantly smaller than that of the older participants (7.9 +/- 2.2 cm, p = 0.007. Those with early-onset visual impairment (78.0% +/- 9.0% also detected drop-offs significantly more reliably than those with later-onset visual impairment (67.3% +/- 12.4%, p = 0.01. No interaction occurred between examined user characteristics (age and age at onset of visual impairment and the type of cane technique used in drop-off detection. The findings of the study may help orientation and mobility specialists select appropriate cane techniques in accordance with the cane user's age and onset of visual impairment.

  5. X-ray computed microtomography for drop shape analysis and contact angle measurement.

    Santini, Maurizio; Guilizzoni, Manfredo; Fest-Santini, Stephanie


    The interaction between an atomized fluid and a solid surface has a great importance in many fields, both in adiabatic conditions and when heat transfer is involved. To investigate the behavior of many drops in contact with a surface, the first step is to study a single one of them and in that, surface wettability is key parameter. Wettability analyses are usually performed by contact angle measurement, in most cases using the sessile drop or captive bubble techniques. Such techniques require optical acquisition of a side view of the drop or bubble, with a series of drawbacks when conventional optics are used, in particular for not uniform, not planar or rough base surfaces. X-ray micro-computed tomography is therefore used to acquire a 3D scan of a drop gently deposited on a surface, with the aim to reconstruct the drop surface and to perform contact angle measurements on true cross-sections of the drop-surface couple. Comparison with contact angle measurements performed on conventional images is performed. The results evidence that the proposed technique is very promising for surface characterization and to get more accurate and detailed information about wettability characteristics.

  6. Petrogenesis and tectonic implications of Early Cretaceous S- and A-type granites in the northwest of the Gan-Hang rift, SE China

    Jiang, Yao-Hui; Zhao, Peng; Zhou, Qing; Liao, Shi-Yong; Jin, Guo-Dong


    The Gan-Hang rift, trending at least 450 km in a NE-SW direction, is a part of a Mesozoic Basin and Range Province in southeastern China. Detailed SHRIMP zircon U-Pb chronology, major and trace element, and Sr-Nd-Hf isotope data of three granitic plutons and a diabasic dike in the northwest of the Gan-Hang rift, are used to explore the origin of these granites and their relationship to the evolution of the Gan-Hang rift. SHRIMP zircon U-Pb dating shows that the granitic plutons and diabasic dike were emplaced in the Early Cretaceous (122-129 Ma). The Tongshan and Damaoshan plutons, close to the Gan-Hang rift, consist mainly of weakly peraluminous granitic rocks, which show A2 subtype affinity. These granites have initial 87Sr/86Sr ratios of 0.7080-0.7103, εNd (T) values of-1.4 to-5.6 and εHf (T) (in-situ zircon) values of - 3.8 to + 1.2. Detailed elemental and isotopic data suggest that they were formed by partial melting of granulitized Mesoproterozoic metamorphic basement (including metasedimentary and metaigneous rocks) in the shallow (residual phase. The association of Early Cretaceous (122-129 Ma) S- and A-type granites in the northwest of the Gan-Hang rift marks the onset of back-arc extension or intra-arc rift. With ongoing extension the crust and lithospheric mantle became progressively thinned. The upwelling of asthenosphere triggered partial melting of both metasedimentary and metaigneous rocks in the more thinned crust close to the Gan-Hang rift, forming the A-type granitic magmas such as Tongshan and Damaoshan, whereas partial melting of metasedimentary rocks in the less thinned crust farther from the Gan-Hang rift formed the S-type granitic magmas such as Ehu. The red sediments with the total thickness more than 10,000 m have been successively deposited in the Gan-Hang rift valley since the late Early Cretaceous (~ 105 Ma), suggesting that this region experienced the most back-arc extension.

  7. Modelling of a thermally activated building system (TABS) combined with free-hanging acoustic ceiling units using computational fluid dynamics (CFD)

    Lacarte, Luis Marcos Domínguez; Fan, Jianhua


    of the heat exchange between the TABS and the room and the occupants. The simulations are validated by comparison with full scale measurements in laboratory conditions. The study shows that for equivalent sound absorption levels, free-hanging vertical sound absorbers have a lower impact on the heat exchange...... between the room and the TABS compared to free-hanging horizontal sound absorbers. Cold air stagnation between the sound absorber units and the TABS has been identified as the major cause of the cooling performance decrease of the TABS....

  8. Spreading of Electrolyte Drops on Charged Surfaces: Electric Double Layer Effects on Drop Dynamics

    Bae, Kyeong; Sinha, Shayandev; Chen, Guang; Das, Siddhartha


    Drop spreading is one of the most fundamental topics of wetting. Here we study the spreading of electrolyte drops on charged surfaces. The electrolyte solution in contact with the charged solid triggers the formation of an electric double layer (EDL). We develop a theory to analyze how the EDL affects the drop spreading. The drop dynamics is studied by probing the EDL effects on the temporal evolution of the contact angle and the base radius (r). The EDL effects are found to hasten the spreading behaviour - this is commensurate to the EDL effects causing a ``philic'' tendency in the drops (i.e., drops attaining a contact angle smaller than its equilibrium value), as revealed by some of our recent papers. We also develop scaling laws to illustrate the manner in which the EDL effects make the r versus time (t) variation deviate from the well known r ~tn variation, thereby pinpointing the attainment of different EDL-mediated spreading regimes.

  9. Blown Away: The Shedding and Oscillation of Sessile Drops by Cross Flowing Air

    Milne, Andrew James Barnabas

    technique to determine mode shapes. Oscillation frequency/mode shape is similar for cross flow and quiescent drops. The highest order models collected from the diffuse literature are seen to be reasonably accurate, except at maximum and minimum ranges of contact angle.

  10. Measurement technique for examining transient transport processes in multi-phase systems: the gas composition in the immediate vicinity of the surface of micro-drops; Messtechnik zur Untersuchung transienter Transportprozesse in Mehrphasensystemen: die Gaszusammensetzung in unmittelbarer Naehe der Oberflaeche von Mikrotropfen

    Moritz, H.; Schweiger, G. [Bochum Univ. (Germany)


    Using the example acetone/acetylene, it was possible to show that measurement of the instantaneous local gas concentration between the drops of a chain of drops is possible. The two-dimensional distribution of concentration of the released gaseous acetylene between the drops was determined. At the same time, the components of the particle phase (acetone and released acetylene) were also measured separately. (orig.) [Deutsch] Am Beispiel des Systems Aceton / Acetylen konnte gezeigt werden, dass eine Messung der momentanen lokalen Gaskonzentration zwischen den Tropfen einer Tropfenkette moeglich ist. Es wurde die zweidimensionale Konzentrationsverteilung des freigesetzten gasfoermigen Acetylens zwischen den Tropfen bestimmt. Gleichzeitig wurden auch die Komponenten der Partikelphase (Aceton und geloestes Acetylen) getrennt voneinander gemessen. (orig.)

  11. Clinical outcomes of sleeveless phacotip assisted levitation of dropped nucleus.

    Agarwal, Amar; Narang, Priya; A Kumar, Dhivya; Agarwal, Ashvin


    To demonstrate the feasibility of a sleeveless phacotip-assisted approach to levitate dropped nucleus. This single-centre, retrospective, interventional, non-comparative case series reviewed the medical records of 34 eyes of 34 patients. Corrected and uncorrected distance visual acuity (CDVA, UDVA), early and late postoperative complications and ultrasound biomicroscopic (UBM) evaluation of the sclerotomy site was analysed. At 18 months follow-up, the mean postoperative UDVA and CDVA in Snellen's decimal equivalent was 0.42 ± 0.16 and 0.91 ± 0.2, respectively. There was a significant improvement in the UDVA (p=0.001) and CDVA (p=0.002). Nucleus drop occurred following intraoperative posterior capsular rupture in 25 eyes (73.5%), zonular weakness in 5 eyes (14.8%) and post-trauma in 4 eyes (11.7%). In the early postoperative period, corneal oedema was seen in 2 eyes, pigment dispersion in 3 eyes and vitritis in 2 eyes. There was loss of CDVA in 1 (2.9%) eye due to persistent cystoid macular oedema. UBM did not reveal any vitreous incarceration into the sclerotomy site. Dropped nucleus was successfully levitated into anterior chamber with this technique, resulting in a significant visual outcome with a favourable complication rate. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to

  12. Drop weld thermal injuries to the middle ear.

    Keogh, I J


    Drop weld injuries to the tympanic membrane and middle ear caused by hot sparks or molten slag are a rare but significant injury. Steel workers and welders who are regularly exposed to flying sparks and molten metal slag are predisposed. This type of transtympanic thermal injury occurs when the slag literally drops into the external auditory canal and burns through the tympanic membrane. A spectrum of severity of injury occurs which includes chronic tympanic membrane perforation, chronic otorrhoea, facial nerve injury and deafness. Chronic tympanic membrane perforation is the most common sequelae and is perhaps one of the most challenging of all perforations to repair The combination of direct thermal injury and foreign body reaction results in continuing or recurrent suppuration. The foreign body reaction is due to the embedding of metal slag in the promontorial mucosa. We present a case of drop weld injury to the left tympanic membrane, resulting in chronic middle ear inflammation, otorrhoea and tympanic perforation. CAT scan clearly demonstrated a metallic promontorial foreign body with localised bone erosion. We emphasise the importance of removing these foreign bodies and recommend a cartilage reinforced underlay tympanoplasty technique to repair these perforations. Transtympanic thermal trauma is a preventable occupational injury, which is best, avoided by earplugs and increased awareness.

  13. Charge and Size Distributions of Electrospray Drops

    de Juan L; de la Mora JF


    The distributions of charge q and diameter d of drops emitted from electrified liquid cones in the cone-jet mode are investigated with two aerosol instruments. A differential mobility analyzer (DMA, Vienna type) first samples the spray drops, selects those with electrical mobilities within a narrow band, and either measures the associated current or passes them to a second instrument. The drops may also be individually counted optically and sized by sampling them into an aerodynamic size spectrometer (API's Aerosizer). For a given cone-jet, the distribution of charge q for the main electrospray drops is some 2.5 times broader than their distribution of diameters d, with qmax/qmin approximately 4. But mobility-selected drops have relative standard deviations of only 5% for both d and q, showing that the support of the (q, d) distribution is a narrow band centered around a curve q(d). The approximate one-dimensionality of this support region is explained through the mechanism of jet breakup, which is a random process with only one degree of freedom: the wavelength of axial modulation of the jet. The observed near constancy of the charge over volume ratio (q approximately d3) shows that the charge is frozen in the liquid surface at the time scale of the breakup process. The charge over volume ratio of the primary drops varies between 98 and 55% of the ratio of spray current I over liquid flow rate Q, and decreases at increasing Q. I/Q is therefore an unreliable measure of the charge density of these drops.

  14. Shape oscillation of a levitated drop in an acoustic field

    Ran, Weiyu


    A `star drop' refers to the patterns created when a drop, flattened by some force, is excited into shape mode oscillations. These patterns are perhaps best understood as the two dimensional analog to the more common three dimensional shape mode oscillations. In this fluid dynamics video an ultrasonic standing wave was used to levitate a liquid drop. The drop was then flattened into a disk by increasing the field strength. This flattened drop was then excited to create star drop patterns by exciting the drop at its resonance frequency. Different oscillatory modes were induced by varying the drop radius, fluid properties, and frequency at which the field strength was modulated.

  15. The Application of Electrochemical Impedance Techniques in Analyzing the AC Response of Some Two-electron Transfer Dye Systems

    Farouk Rashwan


    Full Text Available The Electrochemical Impedance Spectroscopic techniques (EIS were used to investigate the behavior of some dye compounds (quinoid systems characterized with 2e-transfer processes. For this purpose, Alizarin Red S (ARS, Alizarin Cyanine (AC, Alizarin Viridin (AV and carminic acid were chosen for the measurements. The EIS experiments were performed using a small AC amplitude (10 mV p-p in addition to a relatively wide frequency range (0.01 Hz ≤ f ≤ 105 Hz. The investigations were carried out at room temperature in aqueous media (HClO4, NaClO4 and KNO3 on the Hanging Mercury Drop Electrode (HMDE and for comparison one experiment only was measured in aprotic solvent (DMF on the Pt-disc electrode. The EIS diagrams of these systems were characterized in the complex plane by two fundamental observations, the first of which is a straight line crossing the real axis at an angle of 45° (or at least nearly so and the second one is two semicircles beside each other corresponding to high-frequency and low-frequency regions, which are implying the presence of well-separated time constants. The EIS characteristic parameters for these dye systems were calculated and discussed.

  16. Controller Design and Analysis of Spacecraft Automatic Levelling and Equalizing Hoist Device based on Hanging Point Adjustment

    Tang Laiying


    Full Text Available Spacecraft Automatic Levelling and Equalizing Hoist Device (SALEHD is a kind of hoisting device developed for eccentric spacecraft level-adjusting, based on hanging point adjustment by utilizing XY-workbench. To make the device automatically adjust the spacecraft to be levelling, the controller for SALEHD was designed in this paper. Through geometry and mechanics analysis for SALEHD and the spacecraft, the mathematical model of the controller is established. And then, the link of adaptive control and the link of variable structure control were added into the controller to adapt the unknown parameter and eliminate the interference of support vehicle. The stability of the controller was analysed, through constructing Lyapunov energy function. It was proved that the controller system is asymptotically stable, and converged to origin that is equilibrium point. So the controller can be applied in SALEHD availably and safely.

  17. Drop splash on a smooth, dry surface

    Riboux, Guillaume; Gordillo, Jose Manuel; Korobkin, Alexander


    It is our purpose here to determine the conditions under which a drop of a given liquid with a known radius R impacting against a smooth impermeable surface at a velocity V, will either spread axisymmetrically onto the substrate or will create a splash, giving rise to usually undesired star-shaped patterns. In our experimental setup, drops are generated injecting low viscosity liquids falling under the action of gravity from a stainless steel hypodermic needle. The experimental observations using two high speed cameras operating simultaneously and placed perpendicularly to each other reveal that, initially, the drop deforms axisymmetrically, with A (T) the radius of the wetted area. For high enough values of the drop impact velocity, a thin sheet of liquid starts to be ejected from A (T) at a velocity Vjet > V for instants of time such that T >=Tc . If Vjet is above a certain threshold, which depends on the solid wetting properties as well as on the material properties of both the liquid and the atmospheric gas, the rim of the lamella dewets the solid to finally break into drops. Using Wagner's theory we demonstrate that A (T) =√{ 3 RVT } and our results also reveal that Tc We - 1 / 2 =(ρV2 R / σ) - 1 / 2 and Vjet We 1 / 4 .

  18. Drop impact entrapment of bubble rings

    Thoraval, M.-J.


    We use ultra-high-speed video imaging to look at the initial contact of a drop impacting on a liquid layer. We observe experimentally the vortex street and the bubble-ring entrapments predicted numerically, for high impact velocities, by Thoraval et al. (Phys. Rev. Lett., vol. 108, 2012, article 264506). These dynamics mainly occur within 50 -s after the first contact, requiring imaging at 1 million f.p.s. For a water drop impacting on a thin layer of water, the entrapment of isolated bubbles starts through azimuthal instability, which forms at low impact velocities, in the neck connecting the drop and pool. For Reynolds number Re above -12 000, up to 10 partial bubble rings have been observed at the base of the ejecta, starting when the contact is -20% of the drop size. More regular bubble rings are observed for a pool of ethanol or methanol. The video imaging shows rotation around some of these air cylinders, which can temporarily delay their breakup into micro-bubbles. The different refractive index in the pool liquid reveals the destabilization of the vortices and the formation of streamwise vortices and intricate vortex tangles. Fine-scale axisymmetry is thereby destroyed. We show also that the shape of the drop has a strong influence on these dynamics. 2013 Cambridge University Press.

  19. Assessing the accuracy of contact angle measurements for sessile drops on liquid-repellent surfaces.

    Srinivasan, Siddarth; McKinley, Gareth H; Cohen, Robert E


    Gravity-induced sagging can amplify variations in goniometric measurements of the contact angles of sessile drops on super-liquid-repellent surfaces. The very large value of the effective contact angle leads to increased optical noise in the drop profile near the solid-liquid free surface and the progressive failure of simple geometric approximations. We demonstrate a systematic approach to determining the effective contact angle of drops on super-repellent surfaces. We use a perturbation solution of the Bashforth-Adams equation to estimate the contact angles of sessile drops of water, ethylene glycol, and diiodomethane on an omniphobic surface using direct measurements of the maximum drop width and height. The results and analysis can be represented in terms of a dimensionless Bond number that depends on the maximum drop width and the capillary length of the liquid to quantify the extent of gravity-induced sagging. Finally, we illustrate the inherent sensitivity of goniometric contact angle measurement techniques to drop dimensions as the apparent contact angle approaches 180°.

  20. Liquid Drop Measuring Device for Analyzing Liquid Properties


    Based on the correlation between certain properties of liquid and the properties of the corresponding liquid drop formed under given conditions, a liquid drop measuring device is utilized to monitor the drop formation process of the liquid sample with photoelectric measuring methods. The mechanical and optical characteristic of the liquid is explored with the optical fibers from the internal of the liquid drop during its formation. The drop head capacitor is utilized to monitor the growth process of the liquid drop to gain the drop volume information related to the physical property of liquid. The unique liquid drop trace containing the integrated properties of liquid is generated, and it is proved by experiment that for different liquids their liquid drop traces are different. The analysis on liquid properties and discrimination between different liquids can be proceeded with the liquid drop trace obtained by the liquid drop measuring device.

  1. The surface temperature of free evaporating drops

    Borodulin, V. Y.; Letushko, V. N.; Nizovtsev, M. I.; Sterlyagov, A. N.


    Complex experimental and theoretical investigation of heat and mass transfer processes was performed at evaporation of free liquid drops. For theoretical calculation the emission-diffusion model was proposed. This allowed taking into account the characteristics of evaporation of small droplets, for which heat and mass transfer processes are not described in the conventional diffusion model. The calculation results of evaporation of droplets of different sizes were compared using two models: the conventional diffusion and emission-diffusion models. To verify the proposed physical model, the evaporation of droplets suspended on a polypropylene fiber was experimentally investigated. The form of droplets in the evaporation process was determined using microphotographing. The temperature was measured on the surfaces of evaporating drops using infrared thermography. The experimental results have showed good agreement with the numerical data for the time of evaporation and the temperature of evaporating drops.

  2. Ultrasonic characterization of single drops of liquids

    Sinha, Dipen N. (Los Alamos, NM)


    Ultrasonic characterization of single drops of liquids. The present invention includes the use of two closely spaced transducers, or one transducer and a closely spaced reflector plate, to form an interferometer suitable for ultrasonic characterization of droplet-size and smaller samples without the need for a container. The droplet is held between the interferometer elements, whose distance apart may be adjusted, by surface tension. The surfaces of the interferometer elements may be readily cleansed by a stream of solvent followed by purified air when it is desired to change samples. A single drop of liquid is sufficient for high-quality measurement. Examples of samples which may be investigated using the apparatus and method of the present invention include biological specimens (tear drops; blood and other body fluid samples; samples from tumors, tissues, and organs; secretions from tissues and organs; snake and bee venom, etc.) for diagnostic evaluation, samples in forensic investigations, and detection of drugs in small quantities.

  3. Drop impact on a flexible fiber

    Dressaire, Emilie; Boulogne, François; Stone, Howard A


    When droplets impact fibrous media, the liquid can be captured by the fibers or contact then break away. Previous studies have shown that the efficiency of drop capture by a rigid fiber depends on the impact velocity and defined a threshold velocity below which the drop is captured. However, it is necessary to consider the coupling of elastic and capillary effects to achieve a greater understanding of the capture process for soft substrates. Here, we study experimentally the dynamics of a single drop impacting on a thin flexible fiber. Our results demonstrate that the threshold capture velocity depends on the flexibility of fibers in a non-monotonic way. We conclude that tuning the mechanical properties of fibers can optimize the efficiency of droplet capture.

  4. Secondary breakup of coal water slurry drops

    Zhao, Hui; Liu, Hai-Feng; Xu, Jian-Liang; Li, Wei-Feng


    To investigate secondary atomization of coal water slurry (CWS), deformation and breakup of eight kinds of CWS drops are presented using high speed digital camera. Based on morphology, deformation and breakup regimes of CWS drops can be termed some different modes: deformation, multimode breakup (including two sub-modes: hole breakup and tensile breakup), and shear breakup. Correlations on the ranges of breakup modes are also obtained. The conventional Weber number and Ohnesorge number are found to be insufficient to classify all breakup modes of CWS drops, so two other non-dimensional numbers based on rheology of CWS are suggested to use in the deformation and breakup regime map. Finally, total breakup time is studied and correlated, which increases with Ohnesorge number.

  5. A ‘painted chamber’ in Beverwijk by Jacobus Luberti Augustini: novel insights into the working methods and painting practices in a painted wall-hanging factory

    Verslype, I.; Verhave, J.; Smelt, S.; Keune, K.; Sigmond, H.; van Eikema Hommes, M.; Evans, H.; Muir, K.


    The restoration of the ‘painted chamber’ in Beverwijk by Jacobus Luberti Augustini instigated an in-depth technical study of the room and its painted canvas wall hangings. Through close observation with the naked eye, ultraviolet light, infrared reflectography and the study of paint samples in combi

  6. A ‘painted chamber’ in Beverwijk by Jacobus Luberti Augustini: novel insights into the working methods and painting practices in a painted wall-hanging factory

    Verslype, I.; Verhave, J.; Smelt, S.; Keune, K.; Sigmond, H.; van Eikema Hommes, M.; Evans, H.; Muir, K.


    The restoration of the ‘painted chamber’ in Beverwijk by Jacobus Luberti Augustini instigated an in-depth technical study of the room and its painted canvas wall hangings. Through close observation with the naked eye, ultraviolet light, infrared reflectography and the study of paint samples in

  7. Water drops dancing on ice: how sublimation leads to drop rebound.

    Antonini, C; Bernagozzi, I; Jung, S; Poulikakos, D; Marengo, M


    Drop rebound is a spectacular event that appears after impact on hydrophobic or superhydrophobic surfaces but can also be induced through the so-called Leidenfrost effect. Here we demonstrate that drop rebound can also originate from another physical phenomenon, the solid substrate sublimation. Through drop impact experiments on a superhydrophobic surface, a hot plate, and solid carbon dioxide (commonly known as dry ice), we compare drop rebound based on three different physical mechanisms, which apparently share nothing in common (superhydrophobicity, evaporation, and sublimation), but lead to the same rebound phenomenon in an extremely wide temperature range, from 300 °C down to even below -79 °C. The formation and unprecedented visualization of an air vortex ring around an impacting drop are also reported.

  8. An analytical solution for determination of small contact angles from sessile drops of arbitrary size.

    Allen, Jeffrey S


    An analytical solution to the capillary equation of Young and Laplace is derived that allows determination of the static contact angle based on the volume of a sessile drop and the wetted area of the substrate. This solution does not require numerical integration to determine the drop profile and accounts for surface deformation due to gravitational effects. Calculation of the static contact angle by this method is remarkably simple and accurate when the contact angle is less than 30 degrees. A natural scaling arises in the solution, which provides indication of when a drop is small enough so as to neglect gravitational influences on the surface shape which, for small contact angles, is generally less than 1 microl. The technique described has the simplicity of the spherical cap approximation but remains accurate for any size of sessile drop.

  9. Motion driven by the interface. [pendant drop surface tension in microgravity

    Jayaraj, K.; Cole, R.; Subramanian, R. S.


    Due to the reduction in buoyant forces aboard orbiting spacecraft such as the Space Shuttle, fluid motion driven by gradients in interfacial tension will be important in the processing of materials in space. In this paper, preliminary results from a study of surface tension driven flow in a pendant drop are reported. The drop is heated from above, and the resulting temperature gradients on the drop surface give rise to interfacial tension gradients. These, in turn, drive a circulation in the drop which is made visible by suitable tracers. The velocities are measured using a video technique, and the data on core velocities are found to agree well with results from a predictive theoretical model.

  10. The new Drop Tower catapult system

    von Kampen, Peter; Kaczmarczik, Ulrich; Rath, Hans J.


    The Center of Applied Space Technology and Microgravity (ZARM) was founded in 1985 as an institute of the University Bremen, which focuses on research on gravitational and space-related phenomena. In 1988, the construction of the "Drop Tower" began. Since then, the eye-catching tower with a height of 146 m and its characteristic glass roof has become the emblem of the technology centre in Bremen. The Drop Tower Bremen provides a facility for experiments under conditions of weightlessness. Items are considered weightless, when they are in "free fall", i.e. moving without propulsion within the gravity field of the earth. The height of the tower limits the simple "free fall" experiment period to max. 4.74 s. With the inauguration of the catapult system in December 2004, the ZARM is entering a new dimension. This world novelty will meet scientists' demands of extending the experiment period up to 9.5 s. Since turning the first sod on May 3rd, 1988, the later installation of the catapult system has been taken into account by building the necessary chamber under the tower. The catapult system is located in a chamber 10 m below the base of the tower. This chamber is almost completely occupied by 12 huge pressure tanks. These tanks are placed around the elongation of the vacuum chamber of the drop tube. In its centre there is the pneumatic piston that accelerates the drop capsule by the pressure difference between the vacuum inside the drop tube and the pressure inside the tanks. The acceleration level is adjusted by means of a servo hydraulic breaking system controlling the piston velocity. After only a quarter of a second the drop capsule achieves its lift-off speed of 175 km/h. With this exact speed, the capsule will rise up to the top of the tower and afterwards fall down again into the deceleration unit which has been moved under the drop tube in the meantime. The scientific advantages of the doubled experiment time are obvious: during almost 10 s of high

  11. Electrohydrodynamic removal of particles from drop surfaces

    Nudurupati, S.; Janjua, M.; Singh, P.; Aubry, N.


    A uniform electric field is used for cleaning drops of the particles they often carry on their surface. In a first step, particles migrate to either the drop’s poles or equator. This is due to the presence of an electrostatic force for which an analytical expression is derived. In a second step, particles concentrated near the poles are released into the ambient liquid via tip streaming, and those near the equator are removed by stretching the drop and breaking it into several droplets. In the latter case, particles are all concentrated in a small middle daughter droplet.

  12. Development of revolving drop surface tensiometer.

    Mitani, S; Sakai, K


    A revolving drop surface tensiometer, which measures the surface tension of a small amount of liquid, is proposed. A remarkable feature of this device is that while using the pendant drop method, it employs a centrifugal force to deform the liquid droplet. The centrifugal force induces a large distortion of the droplet, which enables an accurate measurement of the surface tension to be made. In our experimental setup, the centrifugal force can be increased so that the apparent acceleration becomes up to 100 times larger than that due to gravity, and the capability of this method to measure surface tensions was demonstrated with ethylene glycol.

  13. Millikan "oil drop" stabilized by growth.

    Sun, L K; Gertler, A W; Reiss, H


    A diffusion cloud chamber has been used to qualitatively study some dynamic properties of liquid drops by suspending them in an electric field at the plane of saturation (p/ps = 1, where p is the actual partial pressure of the vapor at a given elevation and ps is the equilibrium pressure at that temperature characteristic of that elevation). By varying the strength of the electric field, it is possible to change the size of the suspended droplets and even, if desired, to isolate a single drop.

  14. Transformation of the bridge during drop separation

    Chashechkin, Yu. D.; Prokhorov, V. E.


    The geometry of flows during separation of pendant drops of liquids with significantly different physical properties (alcohol, water, glycerin, oil) has been studied by high-speed video recording. The dynamics of the processes involving the formation of bridges of two characteristic shapes—slightly nonuniform in thickness and with thinning of the upper and lower ends—has been investigated. It has been shown that the shape change of the separated bridge has a number of stages determined by the properties of the liquid. As a result, the bridge is transformed into a small drop—a satellite drop.

  15. Toxicology findings in cases of hanging in the City and County of San Francisco over the 3-year period from 2011 to 2013.

    San Nicolas, A C; Lemos, N P


    In postmortem cases where the cause of death is hanging, toxicological analyses may be considered unnecessary by some medical examiners, toxicologists, and other persons involved in medico-legal investigations because the cause of death seems "obvious." To ascertain if toxicological analyses are necessary when the cause of death is hanging, all 102 hanging cases (25 females; 77 males) from 2011 to 2013 that came under the jurisdiction of the San Francisco Office of the Chief Medical Examiner were examined from a total of 3912 sudden, unexpected, or violent death cases in the same period. Suicide was the manner of death in 99 of these cases, with two accidental and one undetermined death. The average age of decedents was 43.9 years (median 41), the youngest was an 11-year old male and the oldest was an 86-year old female. Of the 102 cases, 33 had negative toxicology while 69 cases had at least one positive toxicology result. Females were equally likely to have negative or positive results (12 and 13 cases respectively), but males were 37.5% more likely to have positive toxicology (n=56) rather than negative toxicology (n=21). For females, alcohol, mirtazapine, venlafaxine, and trazodone were the top psychoactive substances in peripheral blood while THC, cocaine, hydrocodone, bupropion, olanzapine, doxylamine, quetiapine and dextromethorphan were also reported. For males, alcohol, THC, cocaine, amphetamine, methamphetamine, bupropion, and diphenhydramine were the top psychoactive substances in blood, but several other drugs were also found in individual cases. Our study of hanging cases over a 3-year period support the idea that complete postmortem toxicology investigation of hangings should be performed, even when the "obvious" cause of death is asphyxia due to hanging. Many of these cases involved psychoactive substances (most often alcohol and cannabis), and having such knowledge provides a better understanding of the circumstances surrounding the decedent's death

  16. Toxicology findings in suicides: concentrations of ethanol and other drugs in femoral blood in victims of hanging and poisoning in relation to age and gender of the deceased.

    Jones, Alan Wayne; Holmgren, Anita; Ahlner, Johan


    Over-consumption of alcohol and/or abuse of other drugs are closely linked to attempted or completed suicides. In this retrospective 10-year study (2001-2010), we compared the toxicology findings in hanging suicides (n = 4551) with drug poisoning (intoxication) suicides (n = 2468). The mean age of hanging deaths was 49 ± 19 y (±SD) and 80% were male, compared with a mean age of 52 ± 17 y and 47% males for the intoxication deaths. Poly-drug use was more common in poisoning suicides with an average of 3.6 drugs/case compared with 1.8 drugs/case in hangings. Moreover, 31% of hangings were negative for alcohol and/or drugs. Alcohol was detected (>0.20 g/L) in femoral blood in 30% of hanging suicides (mean 1.39 g/L) and 36% of drug poisonings (mean 1.39 g/L). The median BACs did not depend on the person's age or gender (p > 0.05). Ethanol, paracetamol, citalopram, diazepam, propiomazine, alimemazine and zopiclone were amongst the top-ten drugs detected in both methods of suicide. With the exception of ethanol, the concentrations of drugs in blood were considerably higher in the poisoning deaths, as might be expected. Regardless of the method of suicide, antidepressants and/or antipsychotics were common findings, which could implicate mental health as a significant suicide risk factor.

  17. 14 CFR 23.727 - Reserve energy absorption drop test.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Reserve energy absorption drop test. 23.727... Construction Landing Gear § 23.727 Reserve energy absorption drop test. (a) If compliance with the reserve energy absorption requirement in § 23.723(b) is shown by free drop tests, the drop height may not be...

  18. Best Measuring Time for a Millikan Oil Drop Experiment

    Kapusta, J. I.


    In a Millikan oil drop experiment, there is a best measuring time for observing the drop, due to Brownian motion of the drop and the experimenter's reaction time. Derives an equation for the relative error in the measurement of the drop's excess charge, and obtains a formula for the best measuring time. (Author/MLH)

  19. Sessile drop deformations under an impinging jet

    Feng, James Q.


    The problem of steady axisymmetric deformations of a liquid sessile drop on a flat solid surface under an impinging gas jet is of interest for understanding the fundamental behavior of free surface flows as well as for establishing the theoretical basis in process design for the Aerosol direct-write technology. It is studied here numerically using a Galerkin finite-element method, by computing solutions of Navier-Stokes equations. For effective material deposition in Aerosol printing, the desired value of Reynolds number for the laminar gas jet is found to be greater than ~500. The sessile drop can be severely deformed by an impinging gas jet when the capillary number is approaching a critical value beyond which no steady axisymmetric free surface deformation can exist. Solution branches in a parameter space show turning points at the critical values of capillary number, which typically indicate the onset of free surface shape instability. By tracking solution branches around turning points with an arc-length continuation algorithm, critical values of capillary number can be accurately determined. Near turning points, all the free surface profiles in various parameter settings take a common shape with a dimple at the center and bulge near the contact line. An empirical formula for the critical capillary number for sessile drops with contact angle is derived for typical ranges of jet Reynolds number and relative drop sizes especially pertinent to Aerosol printing.

  20. Drop impact entrapment of bubble rings

    Thoraval, M -J; Etoh, T G; Thoroddsen, S T


    We use ultra-high-speed video imaging to look at the initial contact of a drop impacting onto a liquid layer. We observe experimentally the vortex street and the bubble-ring entrapments predicted numerically, for high impact velocities, by Thoraval et al. [Phys. Rev. Lett. 108, 264506 (2012)]. These dynamics occur mostly within 50 {\\mu}s after the first contact, requiring imaging at 1 million frames/sec. For a water drop impacting onto a thin layer of water, the entrapment of isolated bubbles starts through azimuthal instability, which forms at low impact velocities, in the neck connecting the drop and pool. For Re above about 12 000, up to 10 partial bubble-rings have been observed at the base of the ejecta, starting when the contact is about 20% of the drop size. More regular bubble rings are observed for a pool of ethanol or methanol. The video imaging shows rotation around some of these air cylinders, which can temporarily delay their breakup into microbubbles. The different refractive index in the pool l...

  1. Predicting Students Drop Out: A Case Study

    Dekker, Gerben W.; Pechenizkiy, Mykola; Vleeshouwers, Jan M.


    The monitoring and support of university freshmen is considered very important at many educational institutions. In this paper we describe the results of the educational data mining case study aimed at predicting the Electrical Engineering (EE) students drop out after the first semester of their studies or even before they enter the study program…

  2. Scaling the drop size in coflow experiments

    Castro-Hernandez, E; Gordillo, J M [Area de Mecanica de Fluidos, Universidad de Sevilla, Avenida de los Descubrimientos s/n, 41092 Sevilla (Spain); Gundabala, V; Fernandez-Nieves, A [School of Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States)], E-mail:


    We perform extensive experiments with coflowing liquids in microfluidic devices and provide a closed expression for the drop size as a function of measurable parameters in the jetting regime that accounts for the experimental observations; this expression works irrespective of how the jets are produced, providing a powerful design tool for this type of experiments.

  3. Drop Shaping by Laser-Pulse Impact

    Klein, A.L.; Bouwhuis, W.; Visser, C.W.; Lhuissier, H.E.; Sun, C.; Snoeijer, J.H.; Villermaux, E.; Lohse, D.; Gelderblom, H.


    We show how the deposition of laser energy induces propulsion and strong deformation of an absorbing liquid body. Combining high speed with stroboscopic imaging, we observe that a millimeter-sized dyed water drop hit by a millijoule nanosecond laser pulse propels forward at several meters per second

  4. Thermocapillary motion of bubbles and drops

    Subramanian, R. S.


    An account is given of interface-driven motions of drops and bubbles. It is shown that even in the simplest cases, theory predicts exotic flow topologies. Attention is given to several unsolved problems that must be addressed both theoretically and experimentally.

  5. Equilibrium drop surface profiles in electric fields

    Mugele, F.; Buehrle, J.


    Electrowetting is becoming a more and more frequently used tool to manipulate liquids in various microfluidic applications. On the scale of the entire drop, the effect of electrowetting is to reduce the apparent contact angle of partially wetting conductive liquids upon application of an external vo

  6. Sliding viscoelastic drops on slippery surfaces

    Xu, H.; Clarke, A.; Rothstein, J. P.; Poole, R. J.


    We study the sliding of drops of constant-viscosity dilute elastic liquids (Boger fluids) on various surfaces caused by sudden surface inclination. For smooth or roughened hydrophilic surfaces, such as glass or acrylic, there is essentially no difference between these elastic liquids and a Newtonian comparator fluid (with identical shear viscosity, surface tension, and static contact angle). In contrast for embossed polytetrafluoroethylene superhydrophobic surfaces, profound differences are observed: the elastic drops slide at a significantly reduced rate and complex branch-like patterns are left on the surface by the drop's wake including, on various scales, beads-on-a-string like phenomena. Microscopy images indicate that the strong viscoelastic effect is caused by stretching filaments of fluid from isolated islands, residing at pinning sites on the surface pillars, of the order ˜30 μm in size. On this scale, the local strain rates are sufficient to extend the polymer chains, locally increasing the extensional viscosity of the solution, retarding the drop and leaving behind striking branch-like structures on much larger scales.

  7. Liquid drops sliding down an inclined plane

    Kim, Inwon


    We investigate a one-dimensional model describing the motion of liquid drops sliding down an inclined plane (the so-called quasi-static approximation model). We prove existence and uniqueness of a solution and investigate its long time behavior for both homogeneous and inhomogeneous medium (i.e. constant and non-constant contact angle). We also obtain some homogenization results.

  8. Drop-Out Challenges: Pathways to Success

    Conner, Evguenia; McKee, Jan


    This article describes an action research at an alternative high school which explores drop-out prevention strategies with first-year students. Student retention is extremely challenging for alternative schools. Because their mission is to provide a second chance to students who could not succeed in a regular setting, those schools regularly must…

  9. 49 CFR 178.965 - Drop test.


    ... Large Packaging design types and performed periodically as specified in § 178.955(e) of this subpart. (b... § 178.960(d). (d) Test method. (1) Samples of all Large Packaging design types must be dropped onto a... be restored to the upright position for observation. (2) Large Packaging design types with a capacity...

  10. Utah Drop-Out Drug Use Questionnaire.

    Governor's Citizen Advisory Committee on Drugs, Salt Lake City, UT.

    This questionnaire assesses drug use practices in high school drop-outs. The 79 items (multiple choice or apply/not apply) are concerned with demographic data and use, use history, reasons for use/nonuse, attitudes toward drugs, availability of drugs, and drug information with respect to narcotics, amphetamines, LSD, Marijuana, and barbiturates.…

  11. Standardisation of superheated drop and bubble detectors

    Vanhavere, F.; D' Errico, F


    This study presents an analysis of the commercially available superheated drop detectors and bubble detectors, performed in substantial accordance with the guidelines developed by the International Organisation for Standardization (ISO). The analysis was performed in terms of linearity, reproducibility, ageing, minimum detection thresholds, energy and angular dependence of the response and the influence of various climatic conditions. (author)

  12. Utah Drop-Out Drug Use Questionnaire.

    Governor's Citizen Advisory Committee on Drugs, Salt Lake City, UT.

    This questionnaire assesses drug use practices in high school drop-outs. The 79 items (multiple choice or apply/not apply) are concerned with demographic data and use, use history, reasons for use/nonuse, attitudes toward drugs, availability of drugs, and drug information with respect to narcotics, amphetamines, LSD, Marijuana, and barbiturates.…

  13. Acoustic levitation of liquid drops: Dynamics, manipulation and phase transitions.

    Zang, Duyang; Yu, Yinkai; Chen, Zhen; Li, Xiaoguang; Wu, Hongjing; Geng, Xingguo


    The technique of acoustic levitation normally produces a standing wave and the potential well of the sound field can be used to trap small objects. Since no solid surface is involved it has been widely applied for the study of fluid physics, nucleation, bio/chemical processes, and various forms of soft matter. In this article, we survey the works on drop dynamics in acoustic levitation, focus on how the dynamic behavior is related to the rheological properties and discuss the possibility to develop a novel rheometer based on this technique. We review the methods and applications of acoustic levitation for the manipulation of both liquid and solid samples and emphasize the important progress made in the study of phase transitions and bio-chemical analysis. We also highlight the possible open areas for future research. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Annual Occurrence of Meteorite-Dropping Fireballs

    Konovalova, Natalia; Jopek, Tadeusz J.


    The event of Chelyabinsk meteorite has brought about change the earlier opinion about limits of the sizes of potentially dangerous asteroidal fragments that crossed the Earth's orbit and irrupted in the Earth's atmosphere making the brightest fireball. The observations of the fireballs by fireball networks allows to get the more precise data on atmospheric trajectories and coordinates of predicted landing place of the meteorite. For the reason to search the periods of fireball activity is built the annual distribution of the numbers of meteorites with the known fall dates and of the meteorite-dropping fireballs versus the solar longitude. The resulting profile of the annual activity of meteorites and meteorite-dropping fireballs shows several periods of increased activity in the course of the year. The analysis of the atmospheric trajectories and physical properties of sporadic meteorite-dropping fireballs observed in Tajikistan by instrumental methods in the summer‒autumn periods of increased fireballs activity has been made. As a result the structural strength, the bulk density and terminal mass of the studied fireballs that can survive in the Earth atmosphere and became meteorites was obtained. From the photographic IAU MDC_2003 meteor database and published sources based on the orbit proximity as determined by D-criterion of Southworth and Hawkins the fireballs that could be the members of group of meteorite-dropping fireballs, was found. Among the near Earth's objects (NEOs) the searching for parent bodies for meteorite-dropping fireballs was made and the evolution of orbits of these objects in the past on a long interval of time was investigated.

  15. A novel approach to Lab-In-Syringe Head-Space Single-Drop Microextraction and on-drop sensing of ammonia.

    Šrámková, Ivana; Horstkotte, Burkhard; Sklenářová, Hana; Solich, Petr; Kolev, Spas D


    A novel approach to the automation technique Lab-In-Syringe, also known as In-Syringe Analysis, is proposed which utilizes a secondary inlet into the syringe void, used as a size-adaptable reaction chamber, via a channel passing through the syringe piston. This innovative approach allows straightforward automation of head-space single-drop microextraction, involving accurately controlled drop formation and handling, and the possibility of on-drop analyte quantification. The syringe was used in upside-down orientation and in-syringe magnetic stirring was carried out, which allowed homogenous mixing of solutions, promotion of head-space analyte enrichment, and efficient syringe cleaning. The superior performance of the newly developed system was illustrated with the development of a sensitive method for total ammonia determination in surface waters. It is based on head-space extraction of ammonia into a single drop of bromothymol blue indicator created inside the syringe at the orifice of the syringe piston channel and on-drop sensing of the color change via fiber optics. The slope of the linear relationship between absorbance and time was used as the analytical signal. Drop formation and performance of on-drop monitoring was further studied with rhodamine B solution to give a better understanding of the system's performance. A repeatability of 6% RSD at 10 μmol L(-1) NH3, a linear range of up to 25 μmol L(-1) NH3, and a limit of detection of 1.8 μmol L(-1) NH3 were achieved. Study of interferences proved the high robustness of the method towards humic acids, high sample salinity, and the presence of detergents, thus demonstrating the method superiority compared to the state-of-the-art gas-diffusion methods. A mean analyte recovery of 101.8% was found in analyzing spiked environmental water samples.

  16. Nuclear and radiochemical techniques in chemical analysis. Progress report, August 1, 1978-July 31, 1979

    Finston, H. L.; Williams, E. T.


    Studies of homogeneous liquid-liquid extraction have been extended to include (1) a detailed determination of the phase diagram of the system propylene carbonate-water, (2) the extraction of a large variety of both monodentate and bidentate iron complexes, (3) the solvent extraction characteristics of analogues of propylene carbonate, (4) the behavior under pressure of the propylene carbonate water system, and (5) the extraction behavior of alkaline earth - TTA chelates. One consequence of these studies was the observation that the addition of ethanol to propylene carbonate-water or to isobutylene carbonate-water yields a single homogeneous phase. Subsequent evaporation of the ethanol restores the two immiscible phases. Past neutron activation analysis has been attempted for the heavy elements Pb, Bi, Tl at the Brookhaven HFBR (in- or near-core position) and at the Brookhaven CLIF facility. The latter appears more promising and we have initiated a collaborative program to use the CLIF facility. A milking system which can provide ca. 16 of carrier-free /sup 212/Pb was developed for use in an isotope dilution technique for lead. Collaboration with laboratories already determining trace lead by flameless Atomic Absorption or by concentration by electrodeposition into a hanging drop followed by Anodic stripping will be proposed. The Proton X-Ray Emission system has undergone marked improvement with the acquisition of a new high resolution Si(Li) detector and a new multi-channel analyzer system. Various techniques have been explored to dissolve and prepare samples for PIXE analysis and also for verification by Atomic Absorption analysis.

  17. Surface modes of a sessile water drop: An optical tweezer based study

    Ghosh, Shankar; Sharma, Prerna; Bhattacharya, S.


    A high-precision method to study the dynamics of two-fluid interfaces using an optical tweezer and a phase-sensitive detection technique are described. The disturbances set up at the interface are studied by analyzing the motion of an optically trapped particle in the bulk of the fluid, i.e., away from the interface. The usefulness of the technique is demonstrated for the well-known problem of a horizontally vibrated sessile liquid drop. The vibrational modes of the liquid drop excited by sinusoidally vibrating the support in a horizontal plane appear as resonances in the motion of the trapped particle. The nature of the resonance is studied in detail by measuring the real part, the imaginary part, and the phase response of the motion of the particle as a function of the "effective" size of the liquid drop. Excellent quantitative agreement with the theoretically predicted values of the eigenfrequencies and damping of the surface modes is obtained.

  18. Surface modes of a sessile water drop: an optical tweezer based study.

    Ghosh, Shankar; Sharma, Prerna; Bhattacharya, S


    A high-precision method to study the dynamics of two-fluid interfaces using an optical tweezer and a phase-sensitive detection technique are described. The disturbances set up at the interface are studied by analyzing the motion of an optically trapped particle in the bulk of the fluid, i.e., away from the interface. The usefulness of the technique is demonstrated for the well-known problem of a horizontally vibrated sessile liquid drop. The vibrational modes of the liquid drop excited by sinusoidally vibrating the support in a horizontal plane appear as resonances in the motion of the trapped particle. The nature of the resonance is studied in detail by measuring the real part, the imaginary part, and the phase response of the motion of the particle as a function of the "effective" size of the liquid drop. Excellent quantitative agreement with the theoretically predicted values of the eigenfrequencies and damping of the surface modes is obtained.

  19. Coalescence collision of liquid drops I: Off-center collisions of equal-size drops

    Alejandro Acevedo-Malavé


    Full Text Available The Smoothed Particle Hydrodynamics method (SPH is used here to model off-center collisions of equal-size liquid drops in a three-dimensional space. In this study the Weber number is calculated for several conditions of the droplets dynamics and the velocity vector fields formed inside the drops during the collision process are shown. For the permanent coalescence the evolution of the kinetic and internal energy is shown and also the approaching to equilibrium of the resulting drop. Depending of the Weber number three possible outcomes for the collision of droplets is obtained: permanent coalescence, flocculation and fragmentation. The fragmentation phenomena are modeled and the formation of small satellite drops can be seen. The ligament that is formed follows the “end pinching” mechanism and it is transformed into a flat structure.

  20. Coalescence collision of liquid drops II: Off-center collisions of unequal-size drops

    Alejandro Acevedo-Malavé


    Full Text Available We applied the Smoothed Particle Hydrodynamics method to simulate for first time in the three-dimensional space the hydrodynamic off-center collisions of unequal-size liquid drops in a vacuum environment. The Weber number for several conditions of the droplets dynamics is determined. Also the velocity vector fields inside the drops are shown in the collision process. The evolution of the kinetic and internal energy is shown for the permanent coalescence case. The resulting drops tend to deform, and depending of the Weber number two possible outcomes for the collision of droplets arise: either permanent coalescence or flocculation. In the permanent coalescence of the drops a fragmentation case is modeled, yielding the formation of little satellite droplets.

  1. Estimates of pressure gradients in PEMFC gas channels due to blockage by static liquid drops

    Venkatraman, M.; Shimpalee, S.; Van Zee, J.W. [Department of Chemical Engineering, University of South Carolina, 301 Main St., Columbia, SC 29208 (United States); Moon, Sung In; Extrand, C.W. [Entegris, Inc., 3500 Lyman Boulevard, Chaska, MN 55318 (United States)


    Numerical analyses are presented to explain the effect of drop size and contact angle on local pressures inside small channels. These pressures and channel characteristics are of interest when water condenses in the gas channels of Proton Exchange Membrane Fuel Cells and hence the study uses Reynolds numbers consistent with as typical utilization of reacting gases in 200 cm{sup 2} flow fields (i.e., 200 < Re < 1500 and stoichiometries of 1.2-2.0 at 1.0 A/cm{sup 2}). The analyses were performed using three-dimensional computational fluid dynamic techniques and the results show that pressure drops are minimal until the blockage was greater than 50%. As blockage increased further, due to larger drops or increased hydrophobicity, pressure drop increased. The results of a stagnant drop are supported by visualization experiments, which show minimal distortion of the drop for these low flow rates, small ratios, and hydrophobic contact angles. Proper scaling parameters and design criteria for microchannels validation experiments are presented. (author)

  2. Step-by-step isolated resection of segment 1 of the liver using the hanging maneuver.

    López-Andújar, Rafael; Montalvá, Eva; Bruna, Marcos; Jiménez-Fuertes, Montiel; Moya, Angel; Pareja, Eugenia; Mir, Jose


    The caudate lobe can be the origin of primary liver tumours or the sole site of liver metastases. This lobe is anatomically divided into 3 parts: Spiegel's lobe (Couinaud's segment 1), paracaval portion (Couinaud's segment 9), and the caudate process. In this series of 4 cases, we provide a step-by-step description of a surgical technique variation that can be applied to resections of lesions localized in segment 1. We believe that other than size, lesion removal in this hepatic anatomic area, which is difficult to perform, can be done more easily using this new approach because it requires minimal mobilization without unnecessary parenchyma transection of other liver parts. Therefore, it reduces the risk of lesions in the inferior vena cava and the middle hepatic vein and respects adequate margins without the use of clamping maneuvers and in an acceptable surgical time.

  3. Pollination Drop in Juniperus communis: Response to Deposited Material

    Mugnaini, Serena; Nepi, Massimo; Guarnieri, Massimo; Piotto, Beti; Pacini, Ettore


    Background and Aims The pollination drop is a liquid secretion produced by the ovule and exposed outside the micropyle. In many gymnosperms, pollen lands on the surface of the pollination drop, rehydrates and enters the ovule as the drop retracts. The objective of this work was to study the formation of the pollination drop in Juniperus communis, its carbohydrate composition and the response to deposition of conspecific pollen, foreign pollen and other particulate material, in an attempt to clarify the mechanism of pollination drop retraction. Method Branches with female cones close to pollination drop secretion were collected. On the first day of pollination drop exposure, an eyelash mounted on a wooden stick with paraffin was used to collect pollen or silica gel particles, which were then deposited by contact with the drop. Volume changes in pollination drops were measured by using a stereomicroscope with a micrometer eyepiece 3 h after deposition. The volume of non-pollinated control drops was also recorded. On the first day of secretion, drops were also collected for sugar analysis by high-performance liquid chromatography. Key Results The pollination drop persisted for about 12 d if not pollinated, and formed again after removal for up to four consecutive days. After pollination with viable conspecific pollen, the drop retracted quickly and did not form again. Partial withdrawal occurred after deposition of other biological and non-biological material. Fructose was the dominant sugar; glucose was also present but at a much lower percentage. Conclusions Sugar analysis confirmed the general trend of fructose dominance in gymnosperm pollination drops. Complete pollination drop withdrawal appears to be triggered by a biochemical mechanism resulting from interaction between pollen and drop constituents. The results of particle deposition suggest the existence of a non-specific, particle-size-dependent mechanism that induces partial pollination drop withdrawal

  4. Semisupervised Community Detection by Voltage Drops

    Min Ji


    Full Text Available Many applications show that semisupervised community detection is one of the important topics and has attracted considerable attention in the study of complex network. In this paper, based on notion of voltage drops and discrete potential theory, a simple and fast semisupervised community detection algorithm is proposed. The label propagation through discrete potential transmission is accomplished by using voltage drops. The complexity of the proposal is OV+E for the sparse network with V vertices and E edges. The obtained voltage value of a vertex can be reflected clearly in the relationship between the vertex and community. The experimental results on four real networks and three benchmarks indicate that the proposed algorithm is effective and flexible. Furthermore, this algorithm is easily applied to graph-based machine learning methods.




    Full Text Available Mobile Ad-hoc NETwork (MANET is an application of wireless network with self-configuring mobile nodes. MANET does not require any fixed infrastructure. Its development never has any threshold range. Nodes in MANET can communicate with each other if and only if all the nodes are in the same range. This wide distribution of nodes makes MANET vulnerable to various attacks, packet dropping attack or black hole attack is one of the possible attack. It is very hard to detect and prevent. To prevent from packet dropping attack, detection of misbehavior links and selfish nodes plays a vital role in MANETs. In this paper, a omprehensive investigation on detection of misbehavior links and malicious nodes is carried out.

  6. A pressure drop model for PWR grids

    Oh, Dong Seok; In, Wang Ki; Bang, Je Geon; Jung, Youn Ho; Chun, Tae Hyun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)


    A pressure drop model for the PWR grids with and without mixing device is proposed at single phase based on the fluid mechanistic approach. Total pressure loss is expressed in additive way for form and frictional losses. The general friction factor correlations and form drag coefficients available in the open literatures are used to the model. As the results, the model shows better predictions than the existing ones for the non-mixing grids, and reasonable agreements with the available experimental data for mixing grids. Therefore it is concluded that the proposed model for pressure drop can provide sufficiently good approximation for grid optimization and design calculation in advanced grid development. 7 refs., 3 figs., 3 tabs. (Author)

  7. Diffraction and interference of walking drops

    Pucci, Giuseppe; Harris, Daniel M.; Bush, John W. M.


    A decade ago, Yves Couder and Emmanuel Fort discovered a wave-particle association on the macroscopic scale: a drop can bounce indefinitely on a vibrating bath of the same liquid and can be piloted by the waves that it generates. These walking droplets have been shown to exhibit several quantum-like features, including single-particle diffraction and interference. Recently, the original diffraction and interference experiments of Couder and Fort have been revisited and contested. We have revisited this system using an improved experimental set-up, and observed a strong dependence of the behavior on system parameters, including drop size and vibrational forcing. In both the single- and the double-slit geometries, the diffraction pattern is dominated by the interaction of the walking droplet with a planar boundary. Critically, in the double-slit geometry, the walking droplet is influenced by both slits by virtue of its spatially extended wave field. NSF support via CMMI-1333242.

  8. Measuring Pressure Drop Under Non Ideal Conditions

    Austin M


    Full Text Available The method of measurement of the pressure drop (PD of cigarette filter rods and the draw resistance of cigarettes is defined in ISO 6565-2002 (1. This standard defines the calibration and use of a transfer standard to calibrate the measuring instrument and also defines the measurement procedure for cigarette and filter samples. The procedure described in the standard assumes that the measurement conditions are constant and that the sample is in equilibrium with the measurement environment.

  9. Probable warfarin interaction with menthol cough drops.

    Coderre, Karen; Faria, Claudio; Dyer, Earl


    Warfarin is a widely used and effective oral anticoagulant; however, the agent has an extensive drug and food interaction profile. We describe a 46-year-old African-American man who was receiving warfarin for a venous thromboembolism and experienced a decrease in his international normalized ratio (INR). No corresponding reduction had been made in his warfarin dosage, and no changes had been made in his concomitant drug therapy or diet. The patient's INR fell from a therapeutic value of 2.6 (target range 2-3) to 1.6 while receiving a weekly warfarin dose of 50 mg. His INR remained stable at 1.6 for 3 weeks despite incremental increases in his warfarin dose. The patient reported that he had been taking 8-10 menthol cough drops/day due to dry conditions at his workplace during the time period that the INR decreased. Five days after discontinuing the cough drops, his INR increased from 1.6 to 2.9. Over the subsequent 5 weeks, his INR was stabilized at a much lower weekly warfarin dose of 40 mg. Use of the Naranjo adverse drug reaction probability scale indicated that the decreased INR was probably related to the concomitant use of menthol cough drops during warfarin therapy. The mechanism for this interaction may be related to the potential for menthol to affect the cytochrome P450 system as an inducer and inhibitor of certain isoenzymes that would potentially interfere with the metabolism of warfarin. To our knowledge, this is the second case report of an interaction between warfarin and menthol. Patients receiving warfarin should be closely monitored, as they may choose to take over-the-counter products without considering the potential implications, and counseled about a possible interaction with menthol cough drops.

  10. Sessile Drop Evaporation and Leidenfrost Phenomenon

    A. K. Mozumder; M. R. Ullah; Hossain, A.; Islam, M A


    Problem statement: Quenching and cooling are important process in manufacturing industry for controlling the mechanical properties of materials, where evaporation is a vital mode of heat transfer. Approach: This study experimentally investigated the evaporation of sessile drop for four different heated surfaces of Aluminum, Brass, Copper and Mild steel with a combination of four different liquids as Methanol, Ethanol, Water and NaCl solution. The time of evaporation for the droplet on the hot...

  11. Low-Pressure-Drop Shutoff Valve

    Thornborrow, John


    Flapper valve remains open under normal flow conditions but closes upon sudden increases to high rate of flow and remains closed until reset. Valve is fluid/mechanical analog of electrical fuse or circuit breaker. Low-pressure-drop shutoff valve contains flapper machined from cylindrical surface. During normal flow conditions, flapper presents small cross section to flow. (Useful in stopping loss of fluid through leaks in cooling systems.)

  12. Modeling Evaporation of Drops of Different Kerosenes

    Bellan, Josette; Harstad, Kenneth


    A mathematical model describes the evaporation of drops of a hydrocarbon liquid composed of as many as hundreds of chemical species. The model is intended especially for application to any of several types of kerosenes commonly used as fuels. The concept of continuous thermodynamics, according to which the chemical composition of the evaporating multicomponent liquid is described by use of a probability distribution function (PDF). However, the present model is more generally applicable than is its immediate predecessor.

  13. Accuracy of surface tension measurement from drop shapes: the role of image analysis.

    Kalantarian, Ali; Saad, Sameh M I; Neumann, A Wilhelm


    Axisymmetric Drop Shape Analysis (ADSA) has been extensively used for surface tension measurement. In essence, ADSA works by matching a theoretical profile of the drop to the extracted experimental profile, taking surface tension as an adjustable parameter. Of the three main building blocks of ADSA, i.e. edge detection, the numerical integration of the Laplace equation for generating theoretical curves and the optimization procedure, only edge detection (that extracts the drop profile line from the drop image) needs extensive study. For the purpose of this article, the numerical integration of the Laplace equation for generating theoretical curves and the optimization procedure will only require a minor effort. It is the aim of this paper to investigate how far the surface tension accuracy of drop shape techniques can be pushed by fine tuning and optimizing edge detection strategies for a given drop image. Two different aspects of edge detection are pursued here: sub-pixel resolution and pixel resolution. The effect of two sub-pixel resolution strategies, i.e. spline and sigmoid, on the accuracy of surface tension measurement is investigated. It is found that the number of pixel points in the fitting procedure of the sub-pixel resolution techniques is crucial, and its value should be determined based on the contrast of the image, i.e. the gray level difference between the drop and the background. On the pixel resolution side, two suitable and reliable edge detectors, i.e. Canny and SUSAN, are explored, and the effect of user-specified parameters of the edge detector on the accuracy of surface tension measurement is scrutinized. Based on the contrast of the image, an optimum value of the user-specified parameter of the edge detector, SUSAN, is suggested. Overall, an accuracy of 0.01mJ/m(2) is achievable for the surface tension determination by careful fine tuning of edge detection algorithms.

  14. Determination of triazine herbicides: development of an electroanalytical method utilizing a solid amalgam electrode that minimizes toxic waste residues, and a comparative study between voltammetric and chromatographic techniques.

    De Souza, Djenaine; de Toledo, Renata A; Galli, Andressa; Salazar-Banda, Giancarlo R; Silva, Maria R C; Garbellini, Gustavo S; Mazo, Luiz H; Avaca, Luis A; Machado, Sergio A S


    The use of a copper solid amalgam electrode (CuSAE) for the analytical determination of triazine herbicides (atrazine and ametryne) instead of the conventional hanging mercury drop electrode (HMDE) is reported. The results obtained using electroanalytical methods utilizing each of these electrodes were also compared with those provided by the HPLC technique. The results indicated that the CuSAE electrode can be used to detect the herbicides studied, since the detection limits reached using the electrode (3.06 microg L-1 and 3.78 microg L-1 for atrazine and ametryne, respectively) are lower than the maximum values permitted by CONAMA (Brazilian National Council for the Environment) for wastewaters (50 microg L-1) and by the US EPA (Environmental Protection Agency of the United States) in natural water samples (10.00 microg L-1). An electroanalytical methodology employing CuSAE and square wave voltammetry (SWV) was successfully applied to the determination of atrazine and ametryne in natural water samples, yielding good recoveries (70.30%-79.40%). This indicates that the CuSAE provides a convenient substitute for the HMDE, particularly since the CuSAE minimizes the toxic waste residues produced by the use of mercury in HDME-based analyses.

  15. Drop floating on a granular raft

    Jambon-Puillet, Etienne; Josserand, Christophe; Protiere, Suzie


    When a droplet comes in contact with a bath of the same liquid, it coalesces to minimize the surface energy. This phenomenon reduces emulsion stability and is usually fought with surfactant molecules. Another way to slow down coalescence is to use colloidal solid particles. In this case the particles spontaneously migrate to the interface to form ``Pickering'' emulsions and act as a barrier between droplets. Here we use dense, large particles (~ 500 μm) which form a monolayer at an oil/water interface that we call a granular raft. When a droplet is placed on top of such a raft, for a given set of particle properties (contact angle/size), the raft prevents coalescence indefinitely. However, in contrast to what happens when a droplet is placed on a hydrophobic surface and never wets the surface, here the droplet is strongly anchored to the raft and deforms it. We will use this specific configuration to probe the mechanical response of the granular raft: by controlling the droplet volume we can impose tensile or compressive stresses. Finally we will show that the drop, spherical at first, slowly takes a more complex shape as it's volume increases. This shape is not reversible as the drop volume is decreased. The drop can become oblate or prolate with wrinkling of the raft.

  16. Drop impacts on electrospun nanofiber membranes

    Sahu, Rakesh P.; Sinha-Ray, Suman; Yarin, Alexander; Pourdeyhimi, Behnam


    This work reports a study of drop impacts of polar and non-polar liquids onto electrospun nanofiber membranes (of 8-10 mm thickness and pore sizes of 3-6 nm) with an increasing degree of hydrophobicity. The nanofibers used were electrospun from polyacrylonitrile (PAN), nylon 6/6, polycaprolactone (PCL) and Teflon. It was found that for any liquid/fiber pair there exists a threshold impact velocity (1.5 to 3 m/s) above which water penetrates membranes irrespective of their wettability. The low surface tension liquid left the rear side of sufficiently thin membranes as a millipede-like system of tiny jets protruding through a number of pores. For such a high surface tension liquid as water, jets immediately merged into a single bigger jet, which formed secondary drops due to capillary instability. An especially non-trivial result is that superhydrophobicity of the porous nano-textured Teflon skeleton with the interconnected pores is incapable of preventing water penetration due to drop impact, even at relatively low impact velocities close to 3.46 m/s. A theoretical estimate of the critical membrane thickness sufficient for complete viscous dissipation of the kinetic energy of penetrating liquid corroborates with the experimental data. The current work is supported by the Nonwovens Cooperative Research Center (NCRC).

  17. Cusp formation in drops inside Taylor cones

    Marin, Alvaro G.; Loscertales, Ignacio G.; Barrero, Antonio


    Here, we report the formation of cusp in insulating drops inside compound Taylor cones. The action of the electrical shear stress acting on the outer interface, which is transmitted by viscous forces inside the Taylor cone, tends to deform the drop of insulating liquid placed inside. For appropriate values of the capillary number, the insulating drop develops a steady cusp angle which depends on both the capillary number and the conducting to insulating viscosity ratio. A self-similar analysis has been developed to qualitatively describe the flow inside these compounds Taylor cones. Any perturbation of the cusp gives rise to an intermittent emission of tiny droplets; this effect may recall the tip-streaming observed by G.I. Taylor in his four-roll mill device. This emission can be stabilized by an appropriate control of the injected flow rate of the insulating liquid. When the capillary number increases, the cusped interface turns into a spout which flows coated by the conducting liquid forming the electrified coaxial jet which has been successfully employed for the production of nanocapsules, coaxial nanofibers and nanotubes (Science 295, n. 5560, 1695, 2002; JACS 126, 5376, 2004).

  18. Low arc drop hybrid mode thermionic converter

    Shimada, K.


    The hybrid mode operation for the reduction of plasma drops is being investigated. This report discusses the results obtained from two molybdenum emitter converters. One converter had a molybdenum collector and the other a nickel collector. The molybdenum collector converter was operated in a hybrid mode (at an interelectrode distance of 1.7 mm) and produced a minimum barrier index of 1.96 eV at an emitter temperature of 1500 K. The arc drop was calculated to be 0.14 eV, using the published results for a molybdenum collector. On the other hand, the nickel collector converter was operated in a conventional ignited mode (at an interelectrode distance of 0.5 mm) and produced a minimum barrier index of 2.1 eV at an emitter temperature of 1700 K. It is tentatively concluded that a large-gap operation of the hybrid mode converter permits the diffusion of cesium ions to a distance in the order of one millimeter for an effective neutralization of electron space charge. By employing a low work function collector (1.55 eV) in a hybrid mode converter with an arc drop of 0.14 eV, it appears that a barrier index as low as 1.69 eV could be achieved.

  19. Sensitive All-Optical Channel-Drop Sensor in Photonic Crystals

    Liu, Y.; Salemink, H.W.M.


    We report the results of a study of an optical sensor based on a channel-drop technique with two cascaded cavities in photonic-crystal slabs. Quality factors and intensities of the resonant modes of the sensor were analyzed with three-dimensional simulations. With the introduction of a reflector in




    Axisymmetric drop shape analysis by profile (ADSA-P) is a technique developed in colloid and surface science to simultaneously determine the contact angle and liquid surface tension from the profile of a droplet resting on a solid surface. In this paper is described how ADSA-P can be employed to ass

  1. Climate warming and stability of cold hanging glaciers: Lessons from the gigantic 1895 Altels break-off

    Faillettaz, Jerome; Funk, Martin


    The Altels hanging glacier broke off on September 11, 1895. The ice volume of this catastrophic rupture was estimated at $\\rm 4.10^6$ cubic meters and is the largest ever observed ice fall event in the Alps. The causes of this collapse are however not entirely clear. Based on previous studies, we reanalyzed this break-off event, with the help of a new numerical model, initially developed by Faillettaz and others (2010) for gravity-driven instabilities. The simulations indicate that a break-off event is only possible when the basal friction at the bedrock is reduced in a restricted area, possibly induced by the storage of infiltrated water within the glacier. Moreover, our simulations reveal a two-step behavior: (i) A first quiescent phase, without visible changes, with a duration depending on the rate of basal changes; (ii) An active phase with a rapid increase of basal motion over a few days. The general lesson obtained from the comparison between the simulations and the available evidence is that visible si...

  2. Development of downflow hanging sponge (DHS) reactor as post treatment of existing combined anaerobic tank treating natural rubber processing wastewater.

    Watari, Takahiro; Cuong Mai, Trung; Tanikawa, Daisuke; Hirakata, Yuga; Hatamoto, Masashi; Syutsubo, Kazuaki; Fukuda, Masao; Nguyen, Ngoc Bich; Yamaguchi, Takashi


    Conventional aerated tank technology is widely applied for post treatment of natural rubber processing wastewater in Southeast Asia; however, a long hydraulic retention time (HRT) is required and the effluent standards are exceeded. In this study, a downflow hanging sponge (DHS) reactor was installed as post treatment of anaerobic tank effluent in a natural rubber factory in South Vietnam and the process performance was evaluated. The DHS reactor demonstrated removal efficiencies of 64.2 ± 7.5% and 55.3 ± 19.2% for total chemical oxygen demand (COD) and total nitrogen, respectively, with an organic loading rate of 0.97 ± 0.03 kg-COD m(-3) day(-1) and a nitrogen loading rate of 0.57 ± 0.21 kg-N m(-3) day(-1). 16S rRNA gene sequencing analysis of the sludge retained in the DHS also corresponded to the result of reactor performance, and both nitrifying and denitrifying bacteria were detected in the sponge carrier. In addition, anammox bacteria was found in the retained sludge. The DHS reactor reduced the HRT of 30 days to 4.8 h compared with the existing algal tank. This result indicates that the DHS reactor could be an appropriate post treatment for the existing anaerobic tank for natural rubber processing wastewater treatment.

  3. Study on the effects of sulfur fumigation on chemical constituents and antioxidant activity of Chrysanthemum morifolium cv. Hang-ju.

    Wang, Shan; Hao, Li-Juan; Zhu, Jing-Jing; Zhang, Qi-Wei; Wang, Zhi-Min; Zhang, Xian; Song, Xiao-mei


    The traditional after-harvesting drying method of C. morifolium cv. Hang-ju (HJ) is sun drying, but recently sulfur fumigation is increasingly used as a cheap and convenient method. However, the effects of sulfur fumigation on chemical constituents and potential activities of HJ were unknown. A comprehensively comparison of the chemical profiles between non-fumigated HJ (NHJ) and sulfur-fumigated HJ (SHJ) was conducted by HPLC fingerprints analysis and the discrepant peaks were identified or tentatively assigned by HPLC-ESI/MS(n). Dramatic chemical changes were found that the contents of 4 flavonoid aglycones remarkably increased while those of 7 glycosides significantly reduced which suggested that sulfur-fumigation induced flavonoid glycosides transformed into aglycons by hydrolysis reaction. A significant loss of hydroxycinnamoylquinic acids showed the sulfur fumigation was a destructive effect on HJ. Principal component analysis (PCA) was employed to rapidly discriminate NHJ and SHJ samples. By ICP-OES analysis, it was found that the residue of sulfur of SHJ were three times higher than NHJ (p<0.05). The antioxidant activity of NHJ and SHJ were evaluated by DPPH and FRAP assay, and the results showed that NHJ had much stronger antioxidant activities than SCF (p<0.05). Combining the results of chemical analysis, residue of sulfur and pharmacological evaluation, it showed that the sulfur fumigation was a destructive effect on HJ.

  4. Planned complex suicide by penetrating captive-bolt gunshot and hanging: case study and review of the literature.

    Viel, Guido; Schröder, Ann Sophie; Püschel, Klaus; Braun, Christian


    Captive-bolt guns or slaughterer's guns are devices widely used in meat industry and private farmer households for slaughtering animal stocks. They consist of a simple cylindrical metal tube (barrel) with a metal bolt placed in their centre (around 9-15cm long and 1-1.5cm wide). The bolt is actuated by a trigger pull and is propelled forward by compressed air or by the discharge of a blank powder gun cartridge. Violent deaths inflicted by captive-bolt guns are rarely encountered in forensic practice and are predominantly suicidal events. We report an unusual complex suicide by hanging and self-shooting with a slaughterer's gun in a 21-year-old boy. The victim after putting a ceiling fixed rope around his neck shot himself in the head (occipital region) with a Kerner captive-bolt gun. He used two mirrors (a cosmetic mirror and a man-sized one) in order to properly visualize his back and to target the occipital region of his head. Radiological data (computed tomography with three dimensional reconstruction) and autopsy findings are discussed according to the clinical and forensic literature. A brief review on planned complex suicides is also given.

  5. Hanging canyons of Haida Gwaii, British Columbia, Canada: Fault-control on submarine canyon geomorphology along active continental margins

    Harris, Peter T.; Barrie, J. Vaughn; Conway, Kim W.; Greene, H. Gary


    Faulting commonly influences the geomorphology of submarine canyons that occur on active continental margins. Here, we examine the geomorphology of canyons located on the continental margin off Haida Gwaii, British Columbia, that are truncated on the mid-slope (1200-1400 m water depth) by the Queen Charlotte Fault Zone (QCFZ). The QCFZ is an oblique strike-slip fault zone that has rates of lateral motion of around 50-60 mm/yr and a small convergent component equal to about 3 mm/yr. Slow subduction along the Cascadia Subduction Zone has accreted a prism of marine sediment against the lower slope (1500-3500 m water depth), forming the Queen Charlotte Terrace, which blocks the mouths of submarine canyons formed on the upper slope (200-1400 m water depth). Consequently, canyons along this margin are short (4-8 km in length), closely spaced (around 800 m), and terminate uniformly along the 1400 m isobath, coinciding with the primary fault trend of the QCFZ. Vertical displacement along the fault has resulted in hanging canyons occurring locally. The Haida Gwaii canyons are compared and contrasted with the Sur Canyon system, located to the south of Monterey Bay, California, on a transform margin, which is not blocked by any accretionary prism, and where canyons thus extend to 4000 m depth, across the full breadth of the slope.

  6. Geology and coal resources of the Hanging Woman Creek Study Area, Big Horn and Powder River Counties, Montana

    Culbertson, William Craven; Hatch, Joseph R.; Affolter, Ronald H.


    In an area of 7,200 acres (29 sq km) In the Hanging Woman Creek study area, the Anderson coal bed contains potentially surface minable resources of 378 million short tons (343 million metric tons) of subbituminous C coal that ranges in thickness from 26 to 33 feet (7.9-10.1 m) at depths of less than 200 feet (60 m). Additional potentially surface minable resources of 55 million short tons (50 million metric tons) are contained in the 9-12 foot (2.7-3.7 m) thick Dietz coal bed which lies 50-100 feet (15-30 m) below the Anderson. Analyses of coal from 5 core holes indicates that the Anderson bed contains 0.4 percent sulfur, 5 percent ash, and has a heating value of 8,540 Btu/lb (4,750 Kcal/kg). The trace element content of the coal is generally similar to other coals in the Powder River Basin. The two coal beds are in the Fort Union Formation of Paleocene age which consists of sandstone, siltstone, shale, coal beds, and locally impure limestone. A northeast-trending normal fault through the middle of the area, downthrown on the southeast side, has displaced the generally flat lying strata as much as 300 feet (91 m). Most of the minable coal lies northwest of this fault.

  7. Building a sustainable land public transportation at Ayer Keroh, Malacca: Perspective view from hang tuah jaya municipal council (HTJMC)

    Sukri, Fatin Hafizah; Chew, Boon Cheong; Hamid, Syaiful Rizal; Loo, Heoy Shin


    Sustainable land public transportation (SLPT) aims to promote a better and healthier ways of meeting individual and community needs. Even though sufficient land public transportation have been provided at Ayer Keroh, Malacca but the level of usage among the community is still low as there is the growth in traffic. Hang Tuah Jaya Municipal Council (HTJMC) is responsible to identify the most appropriate strategies to manage the issues regarding SLPT in order to support of the Malacca state vision becoming Green Technology State in the year 2020. Therefore, this paper attempts to examine the strategies involve in building a SLPT, which may enhance the community's welfare. Thus, the proposed theoretical framework is to demonstrate the strategies towards building a SLPT, which can cater issues within the municipal council area. In this qualitative research, an in-depth focus group have been conducted to obtain the primary data. Thirteen (13) executives from HTJMC involved. This study brings a new paradigm in transforming land public transportation at Ayer Keroh to enhance the community welfare. The result found that land use development as the most significant strategy in SLPT, meanwhile the implementation program is the least strategy involved in building a SLPT at Ayer Keroh. Future research requires more information on the factors of implementing of SLPT so that HTJMC can plan an effective SLPT thorough the demand as the data may indicate numbers of passengers who really support to the implementation of SLPT.

  8. A new approach to the surgical treatment of parasitic cysts of the liver: Hepatectomy using the liver hanging maneuver


    AIM: To review 11 patients with parasitic cysts of the liver, who were treated by hepatic lobectomy using the liver hanging maneuver (LHM).METHODS: Between January 2003 and June 2006, we retrospectively analyzed patients who underwent surgical treatment due to parasitic cysts of the liver, at the Ege University School of Medicine, Department of General Surgery. Of these, the patients who underwent hepatic lobectomy using the LHM were reviewed and evaluated for surgical treatment outcome.RESULTS: Over a three-year period, there were 102 patients who underwent surgical treatment for parasitic cysts of the liver. Of these, 11 (10%) patients with parasitic cysts of the liver underwent hepatic lobectomy using the LHM. Presenting symptoms were abdominal pain, dyspepsia, and cholangitis. Cyst locations were as follows: right lobe filled with cyst, 7 (63%); segmental location, 2 (18%); and multiple locations, 2 patients (18%). All patients underwent hepatic lobectomy with an anterior approach using the LHM. The intraoperative blood transfusion requirement was one unit for 3 patients and two units for one patient. Postoperative complications included pulmonary atelectasy (2, 18%)and pleural effusion (2, 18%). No significant morbidity or mortality was observed.CONCLUSION: We concluded that hepatic lobectomy using the LHM should be considered, not only for hepatic tumors or donor hepatectomy, but also to treat parasitic cysts of the liver.

  9. Contact angle dependence of the resonant properties of sessile drops

    Sharp, James


    A simple optical deflection technique was used to monitor the vibrations of microlitre sessile drops of glycerol/water mixtures with glycerol compositions ranging from 0% to 75%. A photodiode was used to detect time dependent variations in the intensity of laser light reflected from the droplets. The intensity variations were Fourier transformed to obtain information about the resonant properties of the drops (frequency and width of the resonance). These experiments were performed on a range of different substrates where the contact angle formed by the droplets varied between 38±2^o and 160±4^o. The measured resonant frequency values were found to be in agreement with a recently developed theory of vibrations which considers standing wave states along the profile length of the droplet. The widths of the resonances were also compared with theories which predict the influence of substrate effects, surface contamination effects and bulk viscous effects on the damping of capillary waves at the free surface of the droplets. These experiments indicate that the dominant source of damping in sessile liquid droplet is due to bulk viscous effects but that for small contact angles damping due to the droplet/substrate interaction becomes more important.

  10. Surfactant and nonlinear drop dynamics in microgravity

    Jankovsky, Joseph Charles


    Large amplitude drop dynamics in microgravity were conducted during the second United States Microgravity Laboratory mission carried onboard the Space Shuttle Columbia (20 October-5 November 1995). Centimeter- sized drops were statically deformed by acoustic radiation pressure and released to oscillate freely about a spherical equilibrium. Initial aspect ratios of up to 2.0 were achieved. Experiments using pure water and varying aqueous concentrations of Triton-X 100 and bovine serum albumin (BSA) were performed. The axisymmetric drop shape oscillations were fit using the degenerate spherical shape modes. The frequency and decay values of the fundamental quadrupole and fourth order shape mode were analyzed. Several large amplitude nonlinear oscillation dynamics were observed. Shape entrainment of the higher modes by the fundamental quadrupole mode occurred. Amplitude- dependent effects were observed. The nonlinear frequency shift, where the oscillation frequency is found to decrease with larger amplitudes, was largely unaffected by the presence of surfactants. The percentage of time spent in the prolate shape over one oscillation cycle was found to increase with oscillation amplitude. This prolate shape bias was also unaffected by the addition of surfactants. These amplitude-dependent effects indicate that the nonlinearities are a function of the bulk properties and not the surface properties. BSA was found to greatly enhance the surface viscoelastic properties by increasing the total damping of the oscillation, while Triton had only a small influence on damping. The surface concentration of BSA was found to be diffusion-controlled over the time of the experiments, while the Triton diffusion rate was very rapid. Using the experimental frequency and decay values, the suface viscoelastic properties of surface dilatational viscosity ( ks ) and surface shear viscosity ( ms ) were found for varying surfactant concentrations using the transcendental equation of Lu

  11. Combining drop-to-drop solvent microextraction with gas chromatography/mass spectrometry using electronic ionization and self-ion/molecule reaction method to determine methoxyacetophenone isomers in one drop of water.

    Wu, Hui-Fen; Yen, Jyh-Hao; Chin, Chen-Che


    A novel analytical technique termed drop-to-drop solvent microextraction (DDSME) was developed to determine three methoxyacetophenone isomers in one drop of water, which were then detected by gas chromatography/mass spectrometry using electronic ionization mass spectrometry for quantification analysis and self-ion/molecule reaction/tandem mass spectrometry for isomer differentiation. The best optimum parameters for the DDSME technique were as follows: extraction time, 5 min; using toluene as the extraction solvent; volume of extraction solvent, 0.5 microL and no salt addition. The advantages of this method are rapidity, convenience, ease of operation, simplicity of the device, and extremely little solvent and sample consumption. The limit of detection (LOD) for this technique was 1 ng/mL. The relative standard deviation was less than 2.6% (n = 5). The linear range of the calibration curve of DDSME is from 0.01 to 5 microg/mL with correlation coefficient (r2) of >0.954. In the comparison of the LOD of DDSME with other sample pretreatment methods including liquid/liquid extraction (LLE), single-drop microextraction (SDME), solid-phase microextraction (SPME), and liquid-phase microextraction (LPME) using a dual gauge microsyringe with hollow fiber methods, this method shows much better in sensitivity than the LLE (25 ng/mL) and it is compatible with SDME (0.5 ng/mL), SPME (0.5 ng/mL), and LPME using a dual gauge microsyringe with a hollow fiber (1 ng/mL). However, DDSME was more convenient than the LPME using a dual gauge microsyringe with a hollow fiber method and much lower cost than the SPME technique.

  12. Dielectrophoresis of a surfactant-laden viscous drop

    Mandal, Shubhadeep; Bandopadhyay, Aditya; Chakraborty, Suman


    The dielectrophoresis of a surfactant-laden viscous drop in the presence of non-uniform DC electric field is investigated analytically and numerically. Considering the presence of bulk-insoluble surfactants at the drop interface, we first perform asymptotic solution for both low and high surface Péclet numbers, where the surface Péclet number signifies the strength of surface convection of surfactants as compared to the diffusion at the drop interface. Neglecting fluid inertia and interfacial charge convection effects, we obtain explicit expression for dielectrophoretic drop velocity for low and high Péclet numbers by assuming small deviation of drop shape from sphericity and small deviation of surfactant concentration from the equilibrium uniform distribution. We then depict a numerical solution, assuming spherical drop, for arbitrary values of Péclet number. Our analyses demonstrate that the asymptotic solution shows excellent agreement with the numerical solution in the limiting conditions of low and high Péclet numbers. The present analysis shows that the flow-induced redistribution of the surfactants at the drop interface generates Marangoni stress, owing to the influence of the surfactant distribution on the local interfacial tension, at the drop interface and significantly alters the drop velocity at steady state. For a perfectly conducting/dielectric drop suspended in perfectly dielectric medium, Marangoni stress always retards the dielectrophoretic velocity of the drop as compared with a surfactant-free drop. For a leaky dielectric drop suspended in another leaky dielectric medium, in the low Péclet number limit, depending on the electrical conductivity and permittivity of both the liquids, the Marangoni stress may aid or retard the dielectrophoretic velocity of the drop. The Marangoni stress also has the ability to move the drop in the opposite direction as compared with a surfactant-free drop. This non-intuitive reverse motion of the drop is

  13. Drop by drop scattering properties of a radar bin : a numerical experiment

    Gires, Auguste; Tchiguirinskaia, Ioulia; Schertzer, Daniel


    This paper presents the development and initial results of a numerical simulation of pseudo-radar observations computed as the sum of the electric field backscattered by each drop. Simulations are carried out for three successive radar bins with a gate length of 30 m and beam width of 1°. The first step is the simulation of a 100 m x 100 m x 100 m volume with all its drops. The 3D raindrop generator relies on the findings on the rainfall field very small scales (mm to few tens of m) spatio-temporal structure, of the HYDROP experiment and a recent analysis of 2D video disdrometer data in a Multifractal framework. More precisely: (i) The Liquid Water Content (LWC) distribution is represented with the help a multiplicative cascade down to 0.5 m, below which it is considered as homogeneous. (ii) Within each 0.5 x 0.5 x 0.5 m3 patch, liquid water is distributed into drops according to a pre-defined Drop Size Distribution (DSD) and located randomly uniformly. (iii) Such configuration is compared with the one consisting of the same drops uniformly distributed over the 50 x 50 x 50 m3 volume. Then the backscattered field by the drops located within a radar bin are computed as the sum a individual contribution. Antenna beam weighing is taken into account Due to the fact that the radar wave length is much smaller than the "patches" size for rainfall, it appears that as theoretically expected we retrieved an exponential distribution for potential measure horizontal reflectivity. A much lower dispersion is noticed for differential reflectivity. We show that a simple ballistic assumption for drop velocities does not enable to reproduce radar observations, and turbulence must be taken into account. Finally the sensitivity of these outputs to the various model parameters is quantified.

  14. Detailed statistical contact angle analyses; "slow moving" drops on inclining silicon-oxide surfaces.

    Schmitt, M; Groß, K; Grub, J; Heib, F


    Contact angle determination by sessile drop technique is essential to characterise surface properties in science and in industry. Different specific angles can be observed on every solid which are correlated with the advancing or the receding of the triple line. Different procedures and definitions for the determination of specific angles exist which are often not comprehensible or reproducible. Therefore one of the most important things in this area is to build standard, reproducible and valid methods for determining advancing/receding contact angles. This contribution introduces novel techniques to analyse dynamic contact angle measurements (sessile drop) in detail which are applicable for axisymmetric and non-axisymmetric drops. Not only the recently presented fit solution by sigmoid function and the independent analysis of the different parameters (inclination, contact angle, velocity of the triple point) but also the dependent analysis will be firstly explained in detail. These approaches lead to contact angle data and different access on specific contact angles which are independent from "user-skills" and subjectivity of the operator. As example the motion behaviour of droplets on flat silicon-oxide surfaces after different surface treatments is dynamically measured by sessile drop technique when inclining the sample plate. The triple points, the inclination angles, the downhill (advancing motion) and the uphill angles (receding motion) obtained by high-precision drop shape analysis are independently and dependently statistically analysed. Due to the small covered distance for the dependent analysis (static to the "slow moving" dynamic contact angle determination. They are characterised by small deviations of the computed values. Additional to the detailed introduction of this novel analytical approaches plus fit solution special motion relations for the drop on inclined surfaces and detailed relations about the reactivity of the freshly cleaned silicon wafer

  15. Injection of Autologous Bone Marrow versus Hanging Cast in Treatment of Humeral Fracture



    to the high risk of non-union and mal-union in humerus shaft fracture, and because applying this simple and inexpensive technique significantly decreased these complications, injecting autologous bone marrow grafts is recommended for accelerating union in cases of humerus fracture.

  16. Rolling ferrofluid drop on the surface of a liquid

    Sterr, V; Morozov, K I; Rehberg, I; Engel, A; Richter, R


    We report on the controlled transport of drops of magnetic liquid, which are swimming on top of a non-magnetic liquid layer. A magnetic field which is rotating in a vertical plane creates a torque on the drop. Due to surface stresses within the immiscible liquid beneath, the drop is propelled forward. We measure the drop speed for different field amplitudes, field frequencies and drop volumes. Simplifying theoretical models describe the drop either as a solid sphere with a Navier slip boundary condition, or as a liquid half-sphere. An analytical expression for the drop speed is obtained which is free of any fitting parameters and is well in accordance with the experimental measurements. Possible microfluidic applications of the rolling drop are also discussed.

  17. Oscillating and star-shaped drops levitated by an airflow

    Bouwhuis, Wilco; Peters, Ivo R; Brunet, Philippe; van der Meer, Devaraj; Snoeijer, Jacco H


    We investigate the spontaneous oscillations of drops levitated above an air cushion, eventually inducing a breaking of axisymmetry and the appearance of `star drops'. This is strongly reminiscent of the Leidenfrost stars that are observed for drops floating above a hot substrate. The key advantage of this work is that we inject the airflow at a constant rate below the drop, thus eliminating thermal effects and allowing for a better control of the flow rate. We perform experiments with drops of different viscosities and observe stable states, oscillations and chimney instabilities. We find that for a given drop size the instability appears above a critical flow rate, where the latter is largest for small drops. All these observations are reproduced by numerical simulations, where we treat the drop using potential flow and the gas as a viscous lubrication layer. Qualitatively, the onset of instability agrees with the experimental results, although the typical flow rates are too large by a factor 10. Our results...

  18. Validation of a DNA mixture statistics tool incorporating allelic drop-out and drop-in.

    Mitchell, Adele A; Tamariz, Jeannie; O'Connell, Kathleen; Ducasse, Nubia; Budimlija, Zoran; Prinz, Mechthild; Caragine, Theresa


    DNA mixture analysis is a current topic of discussion in the forensics literature. Of particular interest is how to approach mixtures where allelic drop-out and/or drop-in may have occurred. The Office of Chief Medical Examiner (OCME) of The City of New York has developed and validated the Forensic Statistical Tool (FST), a software tool for likelihood ratio analysis of forensic DNA samples, allowing for allelic drop-out and drop-in. FST can be used for single source samples and for mixtures of DNA from two or three contributors, with or without known contributors. Drop-out and drop-in probabilities were estimated empirically through analysis of over 2000 amplifications of more than 700 mixtures and single source samples. Drop-out rates used by FST are a function of the Identifiler(®) locus, the quantity of template DNA amplified, the number of amplification cycles, the number of contributors to the sample, and the approximate mixture ratio (either unequal or approximately equal). Drop-out rates were estimated separately for heterozygous and homozygous genotypes. Drop-in rates used by FST are a function of number of amplification cycles only. FST was validated using 454 mock evidence samples generated from DNA mixtures and from items handled by one to four persons. For each sample, likelihood ratios (LRs) were computed for each true contributor and for each profile in a database of over 1200 non-contributors. A wide range of LRs for true contributors was obtained, as true contributors' alleles may be labeled at some or all of the tested loci. However, the LRs were consistent with OCME's qualitative assessments of the results. The second set of data was used to evaluate FST LR results when the test sample in the prosecution hypothesis of the LR is not a contributor to the mixture. With this validation, we demonstrate that LRs generated using FST are consistent with, but more informative than, OCME's qualitative sample assessments and that LRs for non

  19. Primary acoustic signal structure during free falling drop collision with a water surface

    Chashechkin, Yu. D., E-mail:; Prokhorov, V. E., E-mail: [Russian Academy of Sciences, Ishlinskii Institute for Problems in Mechanics (Russian Federation)


    Consistent optical and acoustic techniques have been used to study the structure of hydrodynamic disturbances and acoustic signals generated as a free falling drop penetrates water. The relationship between the structures of hydrodynamic and acoustic perturbations arising as a result of a falling drop contacting with the water surface and subsequent immersion into water is traced. The primary acoustic signal is characterized, in addition to stably reproduced features (steep leading edge followed by long decay with local pressure maxima), by irregular high-frequency packets, which are studied for the first time. Reproducible experimental data are used to recognize constant and variable components of the primary acoustic signal.

  20. Bubble migration inside a liquid drop in a space laboratory

    Annamalai, P.; Shankar, N.; Cole, R.; Subramanian, R. S.


    The design of experiments in materials processing for trials on board the Shuttle are described. Thermocapillary flows will be examined as an aid to mixing in the formation of glasses. Acoustically levitated molten glass spheres will be spot heated to induce surface flow away from the hot spot to induce mixing. The surface flows are also expected to cause internal convective motion which will drive entrained gas bubbles toward the hot spot, a process also enhanced by the presence of thermal gradients. The method is called fining, and will be augmented by rotation of the sphere to cause bubble migration toward the axes of rotation to form one large bubble which is more easily removed. Centering techniques to fix the maximum centering accuracy will also be tried. Ground-based studies of bubble migration in a rotating liquid and in a temperature gradient in a liquid drop are reviewed.

  1. Hydrodynamics and evaporation of a sessile drop of capillary size

    Barash, L Yu


    Fluid dynamics video of an evaporating sessile drop of capillary size is presented. The corresponding simulation represents the description taking into account jointly time dependent hydrodynamics, vapor diffusion and thermal conduction in an evaporating sessile drop. The fluid convection in the drop is driven by Marangoni forces associated with the temperature dependence of the surface tension. For the first time the evolution of the vortex structure in the drop during an evaporation process is obtained.

  2. Hydrodynamics and evaporation of a sessile drop of capillary size

    Barash, L. Yu.


    Fluid dynamics video of an evaporating sessile drop of capillary size is presented. The corresponding simulation represents the description taking into account jointly time dependent hydrodynamics, vapor diffusion and thermal conduction in an evaporating sessile drop. The fluid convection in the drop is driven by Marangoni forces associated with the temperature dependence of the surface tension. For the first time the evolution of the vortex structure in the drop during an evaporation process...

  3. Delayed Frost Growth on Jumping-Drop Superhydrophobic Surfaces

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


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

  4. Inverse Leidenfrost Effect: Levitating Drops on Liquid Nitrogen.

    Adda-Bedia, M; Kumar, S; Lechenault, F; Moulinet, S; Schillaci, M; Vella, D


    We explore the interaction between a liquid drop (initially at room temperature) and a bath of liquid nitrogen. In this scenario, heat transfer occurs through film-boiling: a nitrogen vapor layer develops that may cause the drop to levitate at the bath surface. We report the phenomenology of this inverse Leidenfrost effect, investigating the effect of the drop size and density by using an aqueous solution of a tungsten salt to vary the drop density. We find that (depending on its size and density) a drop either levitates or instantaneously sinks into the bulk nitrogen. We begin by measuring the duration of the levitation as a function of the radius R and density ρd of the liquid drop. We find that the levitation time increases roughly linearly with drop radius but depends weakly on the drop density. However, for sufficiently large drops, R ≥ Rc(ρd), the drop sinks instantaneously; levitation does not occur. This sinking of a (relatively) hot droplet induces film-boiling, releasing a stream of vapor bubbles for a well-defined length of time. We study the duration of this immersed-drop bubbling finding similar scalings (but with different prefactors) to the levitating drop case. With these observations, we study the physical factors limiting the levitation and immersed-film-boiling times, proposing a simple model that explains the scalings observed for the duration of these phenomena, as well as the boundary of (R,ρd) parameter space that separates them.

  5. Impact dynamics of oxidized liquid metal drops

    Xu, Qin; Brown, Eric; Jaeger, Heinrich M.


    With exposure to air, many liquid metals spontaneously generate an oxide layer on their surface. In oscillatory rheological tests, this skin is found to introduce a yield stress that typically dominates the elastic response but can be tuned by exposing the metal to hydrochloric acid solutions of different concentration. We systematically studied the normal impact of eutectic gallium-indium (eGaIn) drops under different oxidation conditions and show how this leads to two different dynamical regimes. At low impact velocity (or low Weber number), eGaIn droplets display strong recoil and rebound from the impacted surface when the oxide layer is removed. In addition, the degree of drop deformation or spreading during impact is controlled by the oxide skin. We show that the scaling law known from ordinary liquids for the maximum spreading radius as a function of impact velocity can still be applied to the case of oxidized eGaIn if an effective Weber number We is employed that uses an effective surface tension factoring in the yield stress. In contrast, no influence on spreading from different oxidations conditions is observed for high impact velocity. This suggests that the initial kinetic energy is mostly damped by bulk viscous dissipation. Results from both regimes can be collapsed in an impact phase diagram controlled by two variables, the maximum spreading factor Pm=R0/Rm, given by the ratio of initial to maximum drop radius, and the impact number K=We/Re4/5, which scales with the effective Weber number We as well as the Reynolds number Re. The data exhibit a transition from capillary to viscous behavior at a critical impact number Kc≈0.1.

  6. Note: A top-view optical approach for observing the coalescence of liquid drops

    Wang, Luhai; Zhang, Guifu; Wu, Haiyi; Yang, Jiming; Zhu, Yujian


    We developed a new device that is capable of top-view optical examination of the coalescence of liquid drops. The device exhibits great potential for visualization, particularly for the early stage of liquid bridge expansion, owing to the use of a high-speed shadowgraph technique. The fluid densities of the two approaching drops and that of the ambient fluid are carefully selected to be negligibly different, which allows the size of the generated drops to be unlimitedly large in principle. The unique system design allows the point of coalescence between two drops to serve as an undisturbed optical pathway through which to image the coalescence process. The proposed technique extended the dimensionless initial finite radius of the liquid bridge to 0.001, in contrast to 0.01 obtained for conventional optical measurements. An examination of the growth of the bridge radius for a water and oil-tetrachloroethylene system provided results similar to Paulsen's power laws of the inertially limited viscous and inertial regimes. Furthermore, a miniscule shift in the center of the liquid bridge was detected at the point of crossover between the two regimes, which can be scarcely distinguished with conventional side-view techniques.

  7. Partial coalescence from bubbles to drops

    Zhang, F. H.


    The coalescence of drops is a fundamental process in the coarsening of emulsions. However, counter-intuitively, this coalescence process can produce a satellite, approximately half the size of the original drop, which is detrimental to the overall coarsening. This also occurs during the coalescence of bubbles, while the resulting satellite is much smaller, approximately 10 %. To understand this difference, we have conducted a set of coalescence experiments using xenon bubbles inside a pressure chamber, where we can continuously raise the pressure from 1 up to 85 atm and thereby vary the density ratio between the inner and outer fluid, from 0.005 up to unity. Using high-speed video imaging, we observe a continuous increase in satellite size as the inner density is varied from the bubble to emulsion-droplet conditions, with the most rapid changes occurring as the bubble density grows up to 15 % of that of the surrounding liquid. We propose a model that successfully relates the satellite size to the capillary wave mode responsible for its pinch-off and the overall deformations from the drainage. The wavelength of the primary wave changes during its travel to the apex, with the instantaneous speed adjusting to the local wavelength. By estimating the travel time of this wave mode on the bubble surface, we also show that the model is consistent with the experiments. This wavenumber is determined by both the global drainage as well as the interface shapes during the rapid coalescence in the neck connecting the two drops or bubbles. The rate of drainage is shown to scale with the density of the inner fluid. Empirically, we find that the pinch-off occurs when 60 % of the bubble fluid has drained from it. Numerical simulations using the volume-of-fluid method with dynamic adaptive grid refinement can reproduce these dynamics, as well as show the associated vortical structure and stirring of the coalescing fluid masses. Enhanced stirring is observed for cases with second

  8. Dynamics of Ferrofluidic Drops Impacting Superhydrophobic Surfaces

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


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

  9. DNA Dynamics in A Water Drop

    Mazur, A K


    Due to its polyionic character the DNA double helix is stable and biologically active only in salty aqueous media where its charge is compensated by solvent counterions. Monovalent metal ions are ubiquitous in DNA environment and they are usually considered as the possible driving force of sequence-dependent modulations of DNA structure that make it recognizable by proteins. In an effort to directly examine this hypothesis, MD simulations of DNA in a water drop surrounded by vacuum were carried out, which relieves the requirement of charge neutrality. Surprisingly, with zero concentration of counterions a dodecamer DNA duplex appears metastable and its structure remains similar to that observed in experiments.

  10. 杭世骏诗文综论%An Overview of Hang Shijun′s Poetry and Prose Works



    In the eighth year of the reign of Emperor Qianlong (the year 1743),Hang Shiju made a for-mal suggestion to the court that people of the Han and Manchu ethnic groups should be equally treated in offi-cial selection.His suggestion infuriated the Emperor Qianlong and led to his dismissal from office at the age of 48.This incident had a lasting influence in the latter half of Hang′s life and also left a deep imprint on his writings both in verse and in prose.Hang is a unique poet and scholar,and also a member of the literati of the south of the Yangtze frustrated in his official career.A close examination of Hang′s writings,in particular,the poems written in his later career,shows that they fully embody the typical spiritual qualities of the literati of the south of the Yangtze,which might include,among other things,confidence rooted in talent,unyielding pride, a strong sense of responsibility,integrity,noble-mindedness,and an aversion to vulgarity even in poverty. These qualities,though persistently seen among the literati of the south of the Yangtze,have different manifes-tations in the Mid-Qing Dynasty as compared with any other period in the Qing Dynasty.Hang′s verse and prose works offer us a valuable glimpse into the spiritual world of the literati of the south of the Yangtze.%乾隆八年,四十八岁的杭世骏因上书言朝廷用人当泯满汉之见,触怒乾隆,被罢官放还,此事深刻地影响了杭世骏的后半生,也深刻地影响了杭世骏诗文的风貌。作为清代雍乾时期一个个性独特的诗人、学者,作为一个仕途遭遇重挫的江南士大夫,其诗文创作尤其是诗歌作品体现了典型的江南文化人的精神品质:高才自信、倔强狂傲、敢于担当、坚守气节,纵然清贫、绝不媚俗。这些在许多江南文化人中一以贯之的精神品质,在清代中期的表现形式,是和清代其他时期不一样的,而杭世骏的诗文作品,则正好给我们提

  11. PROGRAM DROP: A computer program for prediction of evaporation from freely falling multicomponent drops

    Gavin, P.M. [Gavin Consulting, Newark, OH (United States)


    PROGRAM DROP consists of a series of FORTRAN routine which together are used to model the evaporation of a freely falling, multicomponent drop composed of an arbitrary number of volatile species and a single nonvolatile, inert component. The physics underlying the model are clearly identified, and the model`s relationship to previous work in the literature is described. Test cases are used to illustrate the viability of the model and to highlight its potential usefulness in the accurate prediction of multicomponent droplet vaporization in a variety of applications.

  12. Drop volumes and terminal velocities in aqueous two-phase systems

    Bhavasar, P. M.; Jafarabad, K. R.; Pandit, A. B.; Sawant, S. B.; Joshi, J. B. [Bombay Univ. (India). Dept. of Chemical Technology


    Two phase aqueous extraction techniques employed in liquid-liquid extraction equipment such as spray columns and plate columns were studied, with particular attention to predicting drop sizes prior to jetting, and their terminal velocity. In the particular system studied, the values obtained by conventional models as found in the literature were considered inapplicable. A generalised model was constructed using video photographic measurements, and a correlation was developed for the terminal velocities of the drops in aqueous two-phase systems. This simplified model was found to be successful in expressing the terminal rise/fall velocities of droplets covering a specific range of Morton numbers (representing physical properties) from 0.00211 to 11050 and Eotvos numbers (representative of drop size) from 0.091 to 288. 22 refs., 6 figs.

  13. D.R.O.P. The Durable Reconnaissance and Observation Platform

    McKenzie, Clifford; Parness, Aaron


    The Durable Reconnaissance and Observation Platform (DROP) is a prototype robotic platform with the ability to climb concrete surfaces up to 85deg at a rate of 25cm/s, make rapid horizontal to vertical transitions, carry an audio/visual reconnaissance payload, and survive impacts from 3 meters. DROP is manufactured using a combination of selective laser sintering (SLS) and shape deposition manufacturing (SDM) techniques. The platform uses a two-wheel, two-motor design that delivers high mobility with low complexity. DROP extends microspine climbing technology from linear to rotary applications, providing improved transition ability, increased speeds, and simpler body mechanics while maintaining microspines ability to opportunistically grip rough surfaces. Various aspects of prototype design and performance are discussed, including the climbing mechanism, body design, and impact survival.

  14. Max Launch Abort System (MLAS) Landing Parachute Demonstrator (LPD) Drop Test

    Shreves, Christopher M.


    The Landing Parachute Demonstrator (LPD) was conceived as a low-cost, rapidly-developed means of providing soft landing for the Max Launch Abort System (MLAS) crew module (CM). Its experimental main parachute cluster deployment technique and off-the-shelf hardware necessitated a full-scale drop test prior to the MLAS mission in order to reduce overall mission risk. This test was successfully conducted at Wallops Flight Facility on March 6, 2009, with all vehicle and parachute systems functioning as planned. The results of the drop test successfully qualified the LPD system for the MLAS flight test. This document captures the design, concept of operations and results of the drop test.

  15. Vertical vibration and shape oscillation of acoustically levitated water drops

    Geng, D. L.; Xie, W. J.; Yan, N.; Wei, B., E-mail: [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China)


    We present the vertical harmonic vibration of levitated water drops within ultrasound field. The restoring force to maintain such a vibration mode is provided by the resultant force of acoustic radiation force and drop gravity. Experiments reveal that the vibration frequency increases with the aspect ratio for drops with the same volume, which agrees with the theoretical prediction for those cases of nearly equiaxed drops. During the vertical vibration, the floating drops undergo the second order shape oscillation. The shape oscillation frequency is determined to be twice the vibration frequency.

  16. Detailed model of bouncing drops on a bounded, vibrated bath

    Blanchette, Francois; Gilet, Tristan


    We present a detailed model of drops bouncing on a bounded vibrated bath. These drops are known to bounce indefinitely and to exhibit complex and varied vertical dynamics depending on the acceleration of the bath. In addition, in a narrow parameter regime, these drops travel horizontally while being guided by the waves they generate. Our model tracks the drop's vertical radius and position, as well as the eigenmodes of the waves generated via ordinary differential equations only. We accurately capture the vertical dynamics, as well as some of the horizontal dynamics. Our model may be extended to account for interactions with other drops or obstacles, such as slits and corrals.

  17. Deformed liquid marbles: Freezing drop oscillations with powders

    Marston, Jeremy


    In this work we show that when a liquid drop impacts onto a fine-grained hydrophobic powder, the final form of the drop can be very different from the spherical form with which it impacts. In all cases, the drop rebounds due to the hydrophobic nature of the powder. However, we find that above a critical impact speed, the drop undergoes a permanent deformation to a highly non-spherical shape with a near-complete coverage of powder, which then freezes the drop oscillations during rebound. © 2012 Elsevier B.V.

  18. The bounce-splash of a viscoelastic drop

    Hernandez-Sanchez, Federico; Zenit, Roberto


    This is an entry for the Gallery of Fluid Motion of the 61st Annual Meeting of the APS-DFD (fluid dynamics videos). This video shows the collision and rebound of viscoelastic drops against a solid wall. Using a high speed camera, the process of approach, contact and rebound of drops of a viscoelastic liquid is observed. We found that these drops first splash, similar to what is observed in Newtonian colliding drops; after a few instants, the liquid recoils, recovering its original drop shape and bounce off the wall.

  19. Development of a Drop Tester for Portable Electronic Products


    Portable electronic products are susceptible to accidental drop impact which can cause various functional and physical damage. This paper first presents a patent pending drop tester which allows portable electronic products free drop at any orientation and drop height, and then introduces the drop tester experiment setup and its design principle. Using a cellular phone as an experiment object, we obtain some data such as the impact forces, the impact accelerations, and the strain of an interested spot. By analyzing experiment data the influence of impact to products in various states is investigated with the aim to provide help for the design of products and improvement of reliability.

  20. Impact Dynamics of Oxidized Liquid Metal Drops

    Xu, Qin; Jaeger, Heinrich M


    With exposure to air, many liquid metals spontaneously generate an oxide layer on their surface. In oscillatory rheological tests, this skin is found to introduce a yield stress that typically dominates the elastic response but can be tuned by exposing the metal to hydrochloric acid solutions of different concentration. We systematically studied the normal impact of eutectic gallium-indium (eGaIn) drops under different oxidation conditions and show how this leads to two different dynamical regimes. At low impact velocity (or low Weber number), eGaIn droplets display strong recoil and rebound from the impacted surface when the oxide layer is removed. In addition, the degree of drop deformation or spreading during the impact is controlled by the oxide skin. We show that the scaling law known from ordinary liquids for the maximum spreading radius as a function of impact velocity can still be applied to the case of oxidized eGaIn if an effective Weber number $We^{\\star}$ is employed that uses an effective surface...

  1. Vlasov simulations of parallel potential drops

    H. Gunell


    Full Text Available An auroral flux tube is modelled from the magnetospheric equator to the ionosphere using Vlasov simulations. Starting from an initial state, the evolution of the plasma on the flux tube is followed in time. It is found that when applying a voltage between the ends of the flux tube, about two thirds of the potential drop is concentrated in a thin double layer at approximately one Earth radius altitude. The remaining part is situated in an extended region 1–2 Earth radii above the double layer. Waves on the ion timescale develop above the double layer, and they move toward higher altitude at approximately the ion acoustic speed. These waves are seen both in the electric field and as perturbations of the ion and electron distributions, indicative of an instability. Electrons of magnetospheric origin become trapped between the magnetic mirror and the double layer during its formation. At low altitude, waves on electron timescales appear and are seen to be non-uniformly distributed in space. The temporal evolution of the potential profile and the total voltage affect the double layer altitude, which decreases with an increasing field aligned potential drop. A current–voltage relationship is found by running several simulations with different voltages over the system, and it agrees with the Knight relation reasonably well.

  2. Comparison of Personal, Social and Academic Variables Related to University Drop-out and Persistence.

    Bernardo, Ana; Esteban, María; Fernández, Estrella; Cervero, Antonio; Tuero, Ellián; Solano, Paula


    Dropping out of university has serious consequences not only for the student who drops out but also for the institution and society as a whole. Although this phenomenon has been widely studied, there is a need for broader knowledge of the context in which it occurs. Yet research on the subject often focuses on variables that, although they affect drop-out rates, lie beyond a university's control. This makes it hard to come up with effective preventive measures. That is why a northern Spanish university has undertaken a ex post facto holistic research study on 1,311 freshmen (2008/9, 2009/10, and 2010/11 cohorts). The study falls within the framework of the ALFA-GUIA European Project and focuses on those drop-out factors where there is scope for taking remedial measures. This research explored the possible relationship of degree drop-out and different categories of variables: variables related to the educational stage prior to university entry (path to entry university and main reason for degree choice), variables related to integration and coexistence at university (social integration, academic integration, relationships with teachers/peers and value of the living environment) financial status and performance during university studies (in terms of compliance with the program, time devoted to study, use of study techniques and class attendance). Descriptive, correlational and variance analyses were conducted to discover which of these variables really distinguish those students who drop-out from their peers who complete their studies. Results highlight the influence of vocation as main reason for degree choice, path to university entry, financial independency, social and academic adaptation, time devoted to study, use of study techniques and program compliance in the studied phenomenon.

  3. Comparison of Personal, Social and Academic Variables Related to University Drop-out and Persistence

    Bernardo, Ana; Esteban, María; Fernández, Estrella; Cervero, Antonio; Tuero, Ellián; Solano, Paula


    Dropping out of university has serious consequences not only for the student who drops out but also for the institution and society as a whole. Although this phenomenon has been widely studied, there is a need for broader knowledge of the context in which it occurs. Yet research on the subject often focuses on variables that, although they affect drop-out rates, lie beyond a university’s control. This makes it hard to come up with effective preventive measures. That is why a northern Spanish university has undertaken a ex post facto holistic research study on 1,311 freshmen (2008/9, 2009/10, and 2010/11 cohorts). The study falls within the framework of the ALFA-GUIA European Project and focuses on those drop-out factors where there is scope for taking remedial measures. This research explored the possible relationship of degree drop-out and different categories of variables: variables related to the educational stage prior to university entry (path to entry university and main reason for degree choice), variables related to integration and coexistence at university (social integration, academic integration, relationships with teachers/peers and value of the living environment) financial status and performance during university studies (in terms of compliance with the program, time devoted to study, use of study techniques and class attendance). Descriptive, correlational and variance analyses were conducted to discover which of these variables really distinguish those students who drop-out from their peers who complete their studies. Results highlight the influence of vocation as main reason for degree choice, path to university entry, financial independency, social and academic adaptation, time devoted to study, use of study techniques and program compliance in the studied phenomenon.

  4. Microscale fibre alignment by a three-dimensional sessile drop on a wettable pad

    Reznik, S. N.; Salalha, W.; Yarin, A. L.; Zussman, E.

    Fluidic assembly provides solutions for assembling particles with sizes from nano- metres to centimetres. Fluidic techniques based on patterned shapes of monolayers and capillary forces are widely used to assemble microfabrication devices. Usually, for self-assembly, the precondition is that the components must be mobile in a fluidic environment. In the present work, a shape-directed fluidic self-assembly of rod-like microstructures, such as an optical fibre on a wettable pad is demonstrated experimentally with submicrometre positioning precision. A model of the process is proposed, which accounts for the following two stages of the orientation of a fibre submerged in a sessile drop: (i) the drop melting and spreading over a wettable pad; (ii) fibre reorientation related to the surface-tension-driven shrinkage of the drop surface area. At the end of stage (ii), the fibre is oriented along the pad. The experi- mental results for the optical-fibre assembly by a solder joint have been compared to the modelling results, and a reasonable agreement has been found. The major outcome of the experiments and modelling is that surface tension forces on the fibre piercing a drop align the fibre rather than the flow owing to the spreading of the drop over the horizontal pad, i.e. stage (ii) mostly contributes to the alignment.

  5. Predicting Factors of Drop Out Counseling Process in University Psychological Counseling and Guidance Center

    Omer OZER


    Full Text Available Objective: Objective: The purpose of this study is to evaluate the predicting factors the drop out the counseling process. Methods: The study group consists of 555 college students admitted to a Counseling and Guidance Center (CGC and participated in at least one session of counseling after the first view in the 2013-2014 academic year. As a data collection tool, an “Application Form” on the demographic information and the “Brief Symptom Inventory” was applied to the students; and independent samples t-test and binary logistic regression techniques were used in the analysis of the collected data. Results: According to the analysis results, the age of the students attending the counseling process was found to be higher than those who drop out, but no significant difference was found in their psychometric properties in terms of continuation of the counseling process. Only the age of clients and their previous psychiatric help history was found to predict the dropping out counseling process early. Conclusion: Drop outs are less frequently observed in clients having a previous psychiatric help experience. In addition, it was determined that older clients less frequently drop out the counseling process

  6. Failure Mechanisms of Air Entrainment in Drop Impact on Lubricated Surfaces

    Pack, Min; Hu, Han; Kim, Dong-Ook; Zheng, Zhong; Stone, Howard; Sun, Ying; Drexel University Team; Princeton University Team


    Lubricated surfaces have recently been introduced and studied due to their potential benefit in various applications. Combining the techniques of total internal reflection microscopy and reflection interference microscopy, we examine the dynamics of an underlying air film upon drop impact on a lubricated substrate. In contrast to drop impact on solid surfaces where asperities cause random breakup of the entraining air film, we report two air film failure mechanisms on lubricated surfaces. In particular, using thin liquid films of high viscosity, we show that air film rupture shifts from a randomly driven to a controlled event. At low Weber numbers (We) the droplet bounces. At intermediate We, the air film fails at the center as the drop top surface crashes downward owing to impact-induced capillary waves; the resulting liquid-liquid contact time is found to be independent of We. In contrast, at high We, the air film failure occurs much earlier in time at the first inflection point of the air film shape away from the drop center, where the liquid-liquid van der Waals interactions become important. The predictable failure modes of the air film upon drop impact sheds light on droplet deposition in applications such as lubricant-infused self-cleaning surfaces. Support for this work was provided by the National Science Foundation under Grant No. CMMI-1401438 to Y.S.

  7. Tensiometric Characterization of Superhydrophobic Surfaces As Compared to the Sessile and Bouncing Drop Methods.

    Hisler, Valentin; Jendoubi, Hiba; Hairaye, Camille; Vonna, Laurent; Le Houérou, Vincent; Mermet, Frédéric; Nardin, Michel; Haidara, Hamidou


    We have considered in this work the Wilhelmy plate tensiometer to characterize the wetting properties of two model surface textures: (i) a series of three superhydrophobic micropillared surfaces and (ii) a series of two highly water-repellent surfaces microtextured with a femtosecond laser. The wetting forces obtained on these surfaces with the Wilhelmy plate technique were compared to the contact angles of water droplets measured with the sessile drop technique and to the bouncing behavior of water droplets recorded at a high frame rate. We showed that it is possible with this technique to directly measure triple-line anchoring forces that are not accessible with the commonly used sessile drop technique. In addition, we have demonstrated on the basis of the bouncing drop experiments wetting transitions induced by the specific test conditions associated with the Wilhelmy plate tensiometer for the two series of textured surfaces. Finally, the tensiometer technique is proposed as an alternative test for characterizing the wetting properties of highly liquid-repellent surface, especially under immersion conditions.

  8. Direct observation of drops on slippery lubricant-infused surfaces.

    Schellenberger, Frank; Xie, Jing; Encinas, Noemí; Hardy, Alexandre; Klapper, Markus; Papadopoulos, Periklis; Butt, Hans-Jürgen; Vollmer, Doris


    For a liquid droplet to slide down a solid planar surface, the surface usually has to be tilted above a critical angle of approximately 10°. By contrast, droplets of nearly any liquid "slip" on lubricant-infused textured surfaces - so termed slippery surfaces - when tilted by only a few degrees. The mechanism of how the lubricant alters the static and dynamic properties of the drop remains elusive because the drop-lubricant interface is hidden. Here, we image the shape of drops on lubricant-infused surfaces by laser scanning confocal microscopy. The contact angle of the drop-lubricant interface with the substrate exceeds 140°, although macroscopic contour images suggest angles as low as 60°. Confocal microscopy of moving drops reveals fundamentally different processes at the front and rear. Drops recede via discrete depinning events from surface protrusions at a defined receding contact angle, whereas the advancing contact angle is 180°. Drops slide easily, as the apparent contact angles with the substrate are high and the drop-lubricant interfacial tension is typically lower than the drop-air interfacial tension. Slippery surfaces resemble superhydrophobic surfaces with two main differences: drops on a slippery surface are surrounded by a wetting ridge of adjustable height and the air underneath the drop in the case of a superhydrophobic surface is replaced by lubricant in the case of a slippery surface.

  9. Drop-out from the Swedish addiction compulsory care system.

    Padyab, Mojgan; Grahn, Robert; Lundgren, Lena


    Drop-out of addiction treatment is common, however, little is known about drop-out of compulsory care in Sweden. Data from two national register databases were merged to create a database of 4515 individuals sentenced to compulsory care 2001-2009. The study examined (1) characteristics associated with having dropped out from a first compulsory care episode, (2) the relationship between drop-out and returning to compulsory care through a new court sentence, and (3) the relationship between drop-out and mortality. Multivariable logistic regression analysis was used to address Aim 1 and Cox proportional hazards regression modeling was applied to respond to Aims 2 and 3. Age and previous history of crime were significant predictors for drop-out. Clients who dropped out were 1.67 times more likely to return to compulsory care and the hazard of dying was 16% higher than for those who dropped-out. This study finds that 59% of clients assigned to compulsory care drop-out. Younger individuals are significantly more likely to drop-out. Those who drop out are significantly more likely to experience negative outcomes (additional sentence to compulsory care and higher risk of mortality). Interventions need to be implemented that increase motivation of youth to remain in compulsory care. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Asymmetry of Drop Impacts on Patterned Hydrophobic Microstructures

    Willmott, Geoff; Robson, Simon; Broom, Matheu


    When a water drop falls on to a flat solid surface, asymmetries in the geometry of the spreading drop can be specifically determined by patterned surface microstructures. For hydrophobic (or superhydrophobic) micropillar arrays, the most important asymmetric mechanisms appear to be the surface energy of contact lines, and pathways for gas escaping from penetrated microstructure. In this presentation, static wetting and drop impact experiments will be discussed in relation to drop asymmetries. In addition to micropillar arrays, natural superhydrophobic surfaces (leaves) have been studied, and may suggest possibilities for controlling drop impacts in applications. Some of the clearest large scale drop asymmetries on leaves, which are similar to those associated with low drop impact contact times on synthetic surfaces, appear to be caused by features which generate high contact angle hysteresis, and are therefore indicative of poor superhydrophocity.

  11. Destabilising Pickering emulsions by drop flocculation and adhesion.

    Whitby, Catherine P; Khairul Anwar, Hunainah; Hughes, James


    We have investigated how emulsions of water drops coated by organoclay particles destabilise in organic solvents. The drops destabilise and the emulsions undergo a fluid-solid transition if the particles are poorly wetted by the solvent. We show that the drops adhere together and form three-dimensional networks as the fraction of the poor-quality solvent in the mixture increases. Microscopic observations revealed that the drops coalesce into buckled, non-spherical shapes in mixtures rich in poor-quality solvent. A key finding is that destabilisation is favoured under conditions where the energy of adhesion between the particle layers coating drops is comparable to the energy required to detach the particles from the drops. Rupture of the interfacial layer produces particle flocs and uncoated, unstable water drops that settle out of the emulsion.

  12. Drop dynamics on a stretched viscoelastic filament: An experimental study

    Peixinho, Jorge; Renoult, Marie-Charlotte; Crumeyrolle, Olivier; Mutabazi, Innocent


    Capillary pressure can destabilize a thin liquid filament during breakup into a succession of drops. Besides, the addition of a linear, high molecular weight, flexible and soluble polymer is enough to modify the morphology of this instability. In the time period preceding the breakup, the development of beads-on-a-string structures where drops are connected by thin threads is monitored. The drops dynamics involve drop formation, drop migration and drop coalescence. Experiments using a high-speed camera on stretched bridges of viscoelastic polymeric solutions were conducted for a range of viscosities and polymer concentrations. The rheological properties of the solutions are also quantified through conventional shear rheology and normal stress difference. The overall goal of this experimental investigation is to gain more insight into the formation and time evolution of the drops. The project BIOENGINE is co-financed by the European Union with the European regional development fund and by the Normandie Regional Council.

  13. The Oil Drop Experiment: How Did Millikan Decide What Was an Appropriate Drop?

    Niaz, Mansoor


    The oil drop experiment is considered an important contribution to the understanding of modern physics and chemistry. The objective of this investigation is to study and contrast the views and understanding with respect to the experiment of physicists or philosophers of science with those of authors of physics or chemistry textbooks and…

  14. Drop Pinch-Off for Discrete Flows from a Capillary

    Wilson M.C.T.


    Full Text Available The problem of drop formation and pinch-off from a capillary tube under the influence of gravity has been extensively studied when the internal capillary pressure gradient is constant. This ensures a continuous time independent flow field inside the capillary tube typically of the Poiseuille flow type. Characteristic drop ejection behaviour includes: periodic drop ejection, drop ejection with associated satellite production, complex dripping, chaotic behaviour and jetting. It is well known that this characteristic behaviour is governed by the Weber (We and Ohnesorge (Oh numbers (for a given Bond number and may be delineated in a We verses Oh operability diagram. An in-depth physical understanding of drop ejection is also of great importance to industry where the tight control of drop size and ejection velocity are of critical importance in industrial processes such as sealants used in electronics assembly and inkjet printing. However, the use of such a continuous flow approach for drop ejection in industry is often impractical since such flows cannot be operator controlled. For this reason it is important to investigate so-called discrete pipe flows where the flow can be turned on and off at will. This means the flow inside the pipe is now time-dependent being controlled in a step-wise fashion. As a first stage in the investigation of drop pinch-off behaviour in discrete pipe flows this paper will study the critical pinch-off time required for drop ejection starting from a pendant drop. This is the discrete amount of time the pipe flow is turned on for in order for a drop to be ejected from the capillary. A Newtonian incompressible free-surface CFD flow code developed at the University of Leeds is used to investigate the critical pinch-off time for a range of internal pipe velocities (the central flow maximum in Poiseuille flow. It is found that the time required for drop ejection to occur decreases exponentially with internal pipe velocity

  15. China Netcom Hangs Up


    One of the country’s largest telecom serviceproviders is forced to merge as the industry restructures During the Beijing Olympic Gameslast month, billions of spectatorsaround the world watched sportscompetitions and matches on theirtelevisions and computers.

  16. On hanging together

    Burke, Tom


    The 'global' problem of climate change is endlessly discussed, but rarely looked at cold. The crux of the matter is that all of us, everywhere, share this monumental problem. To prosper we need energy security; but if we persist in using fossil fuels with current technologies, our prosperity will founder. The roadmap drawn up at the Bali climate change convention will show what we need to do to hammer out the post-Kyoto regime. But to get through the ferocious complexity of the process, we will need a change of mind-set. Moving away from a focus on who is to blame and who should act first, we must gain a new political maturity.

  17. Nonlinear dynamics of drops and bubbles and chaotic phenomena

    Trinh, Eugene H.; Leal, L. G.; Feng, Z. C.; Holt, R. G.


    Nonlinear phenomena associated with the dynamics of free drops and bubbles are investigated analytically, numerically and experimentally. Although newly developed levitation and measurement techniques have been implemented, the full experimental validation of theoretical predictions has been hindered by interfering artifacts associated with levitation in the Earth gravitational field. The low gravity environment of orbital space flight has been shown to provide a more quiescent environment which can be utilized to better match the idealized theoretical conditions. The research effort described in this paper is a closely coupled collaboration between predictive and guiding theoretical activities and a unique experimental program involving the ultrasonic and electrostatic levitation of single droplets and bubbles. The goal is to develop and to validate methods based on nonlinear dynamics for the understanding of the large amplitude oscillatory response of single drops and bubbles to both isotropic and asymmetric pressure stimuli. The first specific area on interest has been the resonant coupling between volume and shape oscillatory modes isolated gas or vapor bubbles in a liquid host. The result of multiple time-scale asymptotic treatment, combined with domain perturbation and bifurcation methods, has been the prediction of resonant and near-resonant coupling between volume and shape modes leading to stable as well as chaotic oscillations. Experimental investigations of the large amplitude shape oscillation modes of centimeter-size single bubbles trapped in water at 1 G and under reduced hydrostatic pressure, have suggested the possibility of a low gravity experiment to study the direct coupling between these low frequency shape modes and the volume pulsation, sound-radiating mode. The second subject of interest has involved numerical modeling, using the boundary integral method, of the large amplitude shape oscillations of charged and uncharged drops in the presence

  18. Drop splashing is independent of substrate wetting

    Latka, Andrzej; Nagel, Sidney R; de Pablo, Juan J


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

  19. Drop Impact on to Moving Liquid Pools

    Muñoz-Sánchez, Beatriz Natividad; Castrejón-Pita, José Rafael; Castrejón-Pita, Alfonso Arturo; Hutchings, Ian M.


    The deposition of droplets on to moving liquid substrates is an omnipresent situation both in nature and industry. A diverse spectrum of phenomena emerges from this simple process. In this work we present a parametric experimental study that discerns the dynamics of the impact in terms of the physical properties of the fluid and the relative velocity between the impacting drop and the moving liquid pool. The behaviour ranges from smooth coalescence (characterized by little mixing) to violent splashing (generation of multiple satellite droplets and interfacial vorticity). In addition, transitional regimes such as bouncing and surfing are also found. We classify the system dynamics and show a parametric diagram for the conditions of each regime. This work was supported by the EPSRC (Grant EP/H018913/1), the Royal Society, Becas Santander Universidades and the International Relationships Office of the University of Extremadura.

  20. Drop Impact on a Solid Surface

    Josserand, C.


    © Copyright 2016 by Annual Reviews. All rights reserved. A drop hitting a solid surface can deposit, bounce, or splash. Splashing arises from the breakup of a fine liquid sheet that is ejected radially along the substrate. Bouncing and deposition depend crucially on the wetting properties of the substrate. In this review, we focus on recent experimental and theoretical studies, which aim at unraveling the underlying physics, characterized by the delicate interplay of not only liquid inertia, viscosity, and surface tension, but also the surrounding gas. The gas cushions the initial contact; it is entrapped in a central microbubble on the substrate; and it promotes the so-called corona splash, by lifting the lamella away from the solid. Particular attention is paid to the influence of surface roughness, natural or engineered to enhance repellency, relevant in many applications.

  1. Particle-area dependence of mineral dust in the immersion mode: investigations with freely suspended drops in an acoustic levitator

    K. Diehl


    Full Text Available The heterogeneous freezing temperatures of supercooled drops were measured by using an acoustic levitator. This technique allows to freely suspending single drops in air without electrical charges thereby avoiding any electrical influences which may affect the freezing process. Heterogeneous nucleation caused by several mineral dust particles (montmorillonite, two types of illite was investigated in the immersion mode. Drops of 1 \\unit{mm} in radius were monitored by a~video camera during cooling down to −28 °C to simulate the tropospheric temperature range. The surface temperature of the drops was remotely determined with an infra-red thermometer so that the onset of freezing was indicated. For comparisons, measurements with one particle type were additionally performed in the Mainz vertical wind tunnel with drops of 340 \\unit{{\\mu}m} radius freely suspended. The data were interpreted regarding the particle surfaces immersed in the drops. Immersion freezing was observed in a~temperature range between −13 and −26 °C in dependence of particle type and surface area per drop. The results were evaluated by applying two descriptions of heterogeneous freezing, the stochastic and the singular model.

  2. NanoDrop microvolume quantitation of nucleic acids.

    Desjardins, Philippe; Conklin, Deborah


    Biomolecular assays are continually being developed that use progressively smaller amounts of material, often precluding the use of conventional cuvette-based instruments for nucleic acid quantitation for those that can perform microvolume quantitation. The NanoDrop microvolume sample retention system (Thermo Scientific NanoDrop Products) functions by combining fiber optic technology and natural surface tension properties to capture and retain minute amounts of sample independent of traditional containment apparatus such as cuvettes or capillaries. Furthermore, the system employs shorter path lengths, which result in a broad range of nucleic acid concentration measurements, essentially eliminating the need to perform dilutions. Reducing the volume of sample required for spectroscopic analysis also facilitates the inclusion of additional quality control steps throughout many molecular workflows, increasing efficiency and ultimately leading to greater confidence in downstream results. The need for high-sensitivity fluorescent analysis of limited mass has also emerged with recent experimental advances. Using the same microvolume sample retention technology, fluorescent measurements may be performed with 2 μL of material, allowing fluorescent assays volume requirements to be significantly reduced. Such microreactions of 10 μL or less are now possible using a dedicated microvolume fluorospectrometer. Two microvolume nucleic acid quantitation protocols will be demonstrated that use integrated sample retention systems as practical alternatives to traditional cuvette-based protocols. First, a direct A260 absorbance method using a microvolume spectrophotometer is described. This is followed by a demonstration of a fluorescence-based method that enables reduced-volume fluorescence reactions with a microvolume fluorospectrometer. These novel techniques enable the assessment of nucleic acid concentrations ranging from 1 pg/ μL to 15,000 ng/ μL with minimal consumption of

  3. Sessile Drop Evaporation and Leidenfrost Phenomenon

    A. K. Mozumder


    Full Text Available Problem statement: Quenching and cooling are important process in manufacturing industry for controlling the mechanical properties of materials, where evaporation is a vital mode of heat transfer. Approach: This study experimentally investigated the evaporation of sessile drop for four different heated surfaces of Aluminum, Brass, Copper and Mild steel with a combination of four different liquids as Methanol, Ethanol, Water and NaCl solution. The time of evaporation for the droplet on the hot metallic surface was measured and compared with a proposed correlation as well. With the time temperature plot of these experimental data, the Leidenfrost phenomena had been elucidated. In the pool boiling curve for liquid, just after the transition boiling region and before the film boiling region, the heat transfer approaches its minimum value. The corresponding temperature of this minimum value was termed as the Leidenfrost temperature and the phenomenon is known as Leidenfrost phenomena. According to the experimental data, the Leidenfrost temperature was within a range of 150-200°C for all the experimental conditions. Results: This revealed that Leidenfrost temperature was independent of thermo-physical properties of solid and liquid. Sessile drop evaporation time was the maximum for water, then decreases gradually for Nacl solution, methanol and was the minimum for ethanol for a particular solid material. On the other hand, this time was the highest for copper and the lowest for mild steel for a specific liquid. Conclusion: The experimental data for the evaporation time fairly agree with the proposed correlation within a certain range. The collected time and temperature data may be used as a good data bank for the researchers.

  4. Dynamics of Vapor Layer Under a Leidenfrost Drop

    Caswell, Thomas A


    In the Leidenfrost effect a small drop of fluid is levitated above a sufficiently hot surface, on a persistent vapor layer generated by evaporation from the drop. The vapor layer thermally insulates the drop from the surface leading to extraordinarily long drop lifetimes. The top-view shape of the levitated drops can exhibit persistent star-like vibrations. I extend recent work [Burton et al. PRL 2012] to study the bottom surface of the drop using interference-imaging. In this work I use a high-speed camera and automated image analysis to image, locate and classify the interference fringes. From the interference fringes I reconstruct the shape and height profile of the rim where the drop is closest to the surface. I measure the drop-size dependence of the planar vibrational mode frequencies, which agree well with previous work. I observe a distinct breathing mode in the average radius of the drop, the frequency of which scales differently with drop size than the other modes. This breathing mode can be tightly...

  5. Predicting the build/drop tendency of rotary drilling assemblies

    Jogl, P.N.; Burgess, T.M.; Bowling, J.P.


    Today, the majority of rotary bottomhole assemblies (BHA's) for directional control are designed through practical experience and trial and error. This approach can produce satisfactory results when a great deal of local experience can be drawn on. It can prove costly, however, during drilling in a new area because of the increased number of trips and correction runs. This paper demonstrates how a BHA model can be used to predict the directional inclination tendencies of rotary assemblies, thus limiting the uncertainty associated with the traditional BHA design techniques. The technique is demonstrated on data from 17 bit runs from three wells on the same platform in the Gulf of Mexico. Predicted tendencies from BHA descriptions alone proved to be accurate (to an error of +-0.1/sup 0//100 ft-0.03/sup 0//10 ml) in more than half the cases. The uncertainty of other predictions appeared to depend on the hole gauge. The distance taken for a BHA to reach a stable build/drop rate after the start of a bit run depends on the length of the BHA. This factor must be taken into account in the prediction of BHA performance.

  6. Roof Weakening of Hydraulic Fracturing for Control of Hanging Roof in the Face End of High Gassy Coal Longwall Mining: A Case Study

    Huang, Bingxiang; Wang, Youzhuang


    The occurence of hanging roof commonly arises in the face end of longwall coal mining under hard roof conditions. The sudden break and subsequent caving of a hanging roof could result in the extrusion of gas in the gob to the face, causing gas concentrations to rise sharply and to increase to over a safety-limited value. A series of linear fracturing-holes of 32 mm diameter were drilled into the roof of the entries with an anchor rig. According to the theory that the gob should be fully filled with the fragmentized falling roof rock, the drilling depth is determined as being 3 5 times the mining height if the broken expansion coefficient takes an empirical value. Considering the general extension range of cracks and the supporting form of the entryway, the spacing distance between two drilling holes is determined as being 1 2 times the crack's range of extension. Using a mounting pipe, a high pressure resistant sealing device of a small diameter-size was sent to the designated location for the high-pressure hydraulic fracturing of the roof rock. The hydraulic fracturing created the main hydro-fracturing crack and airfoil branch cracks in the interior of the roof-rock, transforming the roof structure and weakening the strength of the roof to form a weak plane which accelerated roof caving, and eventually induced the full caving in of the roof in time with the help of ground pressure. For holes deeper than 4 m, retreating hydraulic fracturing could ensure the uniformity of crack extension. Tested and applied at several mines in Shengdong Mining District, the highest ruptured water pressure was found to be 55 MPa, and the hanging roof at the face end was reduced in length from 12 m to less than 1 2 m. This technology has eliminated the risk of the extrusion of gas which has accumulated in the gob.

  7. Klassiõpetaja peab särama / Ly Melesk, Kairis Kontus, Leida Talts, Viia Hang...[jt.] ; küsitles Anu Mõttus


    Vestlusringis on Tallinna Kuristiku Gümnaasiumi klassiõpetajad Viia Hang ja Ly Melesk, Tallinna Ülikooli 5. kursuse üliõpilane ja Tallinna Lepistiku Lasteaed-Algkooli õpetaja Kairis Kontus, Tallinna Ülikooli algõpetuse õppetooli juhataja Leida Talts ning algõpetuse õppetooli pedagoogika ja algõpetuse metoodika õppejõud Mare Müürsepp. Kui hästi on Tallinna Ülikool ja tema eelkäijad suutnud algklassiõpetajaid ette valmistada ja mis neil igapäevatöös toime tulla aitab

  8. Approach to the Design of Compound MSS Tail Hanging System%复合式移动模架尾部吊挂系统设计探讨

    刘宏刚; 张超福; 侯嵩


    尾部吊挂在已浇筑的混凝土梁面上走行的复合式移动模架因具备支腿自移功能,在国内外桥梁施工中得到大量应用,但此类移动模架的事故率也是相对较高的,且大多缘于吊挂系统的设计或加工缺陷。通过分析吊挂系统在走行过程中受到的多维度不断变化的弯、剪、扭、拉组合作用,结合实际使用中的经验教训,总结其计算、设计、制造及现场处理等方面需要注意的若干事项,并对照这些结论和建议,讨论几种常见的复合式移动模架吊挂系统设计方案的优缺点,以及在设计吊挂系统时动态地、相互关联地按照构件在使用中的真实情况研究其极限状态与破坏规律的重要性。%Owning to the self-moving brackets, the compound MSS with tail hanging running on the surface of cast in situ concrete girder has been widely used in bridge construction at home and abroad. But accidents of the MSS occur frequently, resulted largely from the hanging system design or manufacturing defects. This paper analyzes the hanging system being acted upon by the combination of the multi-dimensional changing of bending, shearing, torsion and pulling in the process of walking. With reference to the lessons learned in the actual operation, a number of issues on its calculation, design, manufacturing, and on - site handling are summarized, the merits and demerits of several common compound MSS designs are discussed on the basis of these conclusions and recommendations, and the importance is addressed of the limit status and failure laws relating to each other according to the element true conditions in use in the designing of the hanging system.

  9. Collision between chemically-driven self-propelled drops

    Yabunaka, Shunsuke


    We consider analytically and numerically head-on collision between two self-propelled drops. Each drop is driven by chemical reactions that produce or consume the concentration isotropically. The isotropic distribution of the concentration field is destabilized by motion of the drop which is itself made by Marangoni flow from concentration-dependent surface tension. This symmetry-breaking self-propulsion is distinct from other self-propulsion mechanisms due to the intrinsic polarity such as squirmers and self-phoretic motion; there is a bifurcation point below which the drop is stationary and above which it moves spontaneously. When two drops moving along the same axis with opposite direction, the interactions arise both from hydrodynamics and concentration overlap. We found that two drops exhibit either elastic collision or fusion depending on the distance from the bifurcation point controlled, for instance, by viscosity. The elastic collision results from the balance between dissipation and energy injection...

  10. Drop Test Results of CRDM under Seismic Loads

    Choi, Myoung-Hwan; Cho, Yeong-Garp; Kim, Gyeong-Ho; Sun, Jong-Oh; Huh, Hyung [KAERI, Daejeon (Korea, Republic of)


    This paper describes the test results to demonstrate the drop performance of CRDM under seismic loads. The top-mounted CRDM driven by the stepping motor for Jordan Research and Training Reactor (JRTR) has been developed in KAERI. The CRDM for JRTR has been optimized by the design improvement based on that of the HANARO. It is necessary to verify the drop performance under seismic loads such as operating basis earthquake (OBE) and safe shutdown earthquake (SSE). Especially, the CAR drop times are important data for the safety analysis. confirm the drop performance under seismic loads. The delay of drop time at Rig no. 2 due to seismic loads is greater than that at Rig no. 3. The total pure drop times under seismic loads are estimated as 1.169 and 1.855, respectively.

  11. Drop Impact on Textile Material: Effect of Fabric Properties

    Romdhani Zouhaier


    Full Text Available This paper presents an experimental study of impact of water drop on a surface in a spreading regime with no splashing. Three surfaces were studied: virgin glass, coating film and woven cotton fabric at different construction parameters. All experiments were carried out using water drop with the same free fall high. Digidrop with high-resolution camera is used to measure the different parameters characterising this phenomenon. Results show an important effect of the height of the free fall on the drop profile and the spreading behaviour. An important drop deformation at the surface impact was observed. Then, fabric construction as the weft count deeply affects the drop impact. For plain weave, an increase of weft count causes a decrease in penetration and increase in the spreading rate. The same result was obtained for coated fabric. Therefore, the impact energy was modified and the drop shape was affected, which directly influenced the spreading rate.

  12. How geometry determines the coalescence of low-viscosity drops

    Eddi, A; Snoeijer, J H


    The coalescence of water drops on a substrate is studied experimentally. We focus on the rapid growth of the bridge connecting the two drops, which very quickly after contact ensues from a balance of surface tension and liquid inertia. For drops with contact angles below $90^\\circ$, we find that the bridge grows with a self-similar dynamics that is characterized by a height $h\\sim t^{2/3}$. By contrast, the geometry of coalescence changes dramatically for contact angles at $90^\\circ$, for which we observe $h\\sim t^{1/2}$, just as for freely suspended spherical drops in the inertial regime. We present a geometric model that quantitatively captures the transition from 2/3 to 1/2 exponent, and unifies the inertial coalescence of sessile drops and freely suspended drops.

  13. Coalescence of bubbles and drops in an outer fluid

    Paulsen, Joseph D; Kannan, Anerudh; Burton, Justin C; Nagel, Sidney R


    When two liquid drops touch, a microscopic connecting liquid bridge forms and rapidly grows as the two drops merge into one. Whereas coalescence has been thoroughly studied when drops coalesce in vacuum or air, many important situations involve coalescence in a dense surrounding fluid, such as oil coalescence in brine. Here we study the merging of gas bubbles and liquid drops in an external fluid. Our data indicate that the flows occur over much larger length scales in the outer fluid than inside the drops themselves. Thus we find that the asymptotic early regime is always dominated by the viscosity of the drops, independent of the external fluid. A phase diagram showing the crossovers into the different possible late-time dynamics identifies a dimensionless number that signifies when the external viscosity can be important.

  14. Ultralow interfacial tensions of aqueous two-phase systems measured using drop shape.

    Atefi, Ehsan; Mann, J Adin; Tavana, Hossein


    Aqueous solutions of different polymers can separate and form aqueous two-phase systems (ATPS). ATPS provide an aqueous, biocompatible, and mild environment for separation and fractionation of biomolecules. The interfacial tension between the two aqueous phases plays a major role in ATPS-mediated partition of biomolecules. Because of the structure of the two aqueous phases, the interfacial tensions between the phases can be 3-4 orders of magnitude smaller than conventional fluid-liquid systems: ∼1-100 μJ/m(2) for ATPS compared to ∼72 mJ/m(2) for the water-vapor interface. This poses a major challenge for the experimental measurements of reproducible interfacial tension data for these systems. We address the need for precise determination of ultralow interfacial tensions by systematically studying a series of polymeric ATPS comprising of polyethylene glycol (PEG) and dextran (DEX) as the phase-forming polymers. Sessile and pendant drops of the denser DEX phase are formed within the immersion PEG phase. An axisymmetric drop shape analysis (ADSA) is used to determine interfacial tensions of eight different ATPS. Specific criteria are used to reproducibly determine ultralow interfacial tensions of the ATPS from pendant and sessile drops. Importantly, for a given ATPS, pendant drop and sessile drop experiments return values within 0.001 mJ/m(2) indicating reliability of our measurements. Then, the pendant drop technique is used to measure interfacial tensions of all eight ATPS. Our measured values range from 0.012 ± 0.001 mJ/m(2) to 0.381 ± 0.006 mJ/m(2) and vary with the concentration of polymers in equilibrated phases of ATPS. Measurements of ultralow interfacial tensions with such reproducibility will broadly benefit studies involving partition of different biomolecules in ATPS and elucidate the critical effect of interfacial tension.

  15. Foraging of the Indian Short-nosed Fruit Bat Cynopterus sphinx on banana in shops and on the pieces dropped by monkeys at a temple

    A. Rathinakumar


    Full Text Available The Indian Short-nosed Fruit Bat Cynopterus sphinx fed on the pieces of banana fruit that were dropped by monkeys on the tower of a temple and in nearby shops.  The monkeys obtained fruits from devotees and shop owners.  The peak number of bat visits occurred during pre- and post- midnight hours at the tower and shops, respectively, coinciding with the lights off situation and reduced human disturbance.  The bats landed on bunches of ripe bananas hanging in the front of shops.  The number of bat landings on the tower was greater than that in the shops.  The overall number of bat visits were higher during October when compared to other periods of the year.  This may be due to the occurrence of more festivals during October.  Our study is an example of opportunistic feeding, in which banana pieces dropped while monkeys were feeding on them were eaten by the bats.

  16. Shaping and Capturing Leidenfrost drops with a magnetic field

    Piroird, Keyvan; Clanet, Christophe; Quéré, David


    Liquid oxygen, which is intrinsically paramagnetic, also undergoes Leidenfrost effect at room temperature. In this article, we first study the deformation of oxygen drops in a magnetic field via an effective capillary length, that includes the magnetic force. In a second part, we show that these ultra-mobile drops passing above a magnet significantly slow down and can even be trapped if slow enough. The critical velocity below which a drop is captured is determined from the deformation induced by the field.

  17. On the coalescence of sessile drops with miscible liquids.

    Borcia, R; Bestehorn, M


    Sessile drops sitting on highly wettable solid substrates fuse in qualitatively different ways after contact, depending on the surface tension gradients between the mixing droplets. In early time evolution the drop coalescence can be fast or delayed (intermittent). In long time evolution a secondary drop formation can occur. We study numerically droplet dynamics during coalescence in two and three spatial dimensions, within a phase field approach. We discuss criteria to distinguish different coalescence regimes. A comparison with recent experiments will be done.

  18. A drop jumps to weightlessness: a lecture demo

    Mayer, V. V.; Varaksina, E. I.; Saranin, V. A.


    The paper discusses the lecture demonstration of the phenomenon in which a drop lying on a solid unwettable substrate jumps when making the transition to weightlessness. An elementary theory of the phenomenon is given. A jump speed estimate is obtained for small and large drops. The natural vibrational frequency of a flying drop is determined. A full-scale model of Einstein’s elevator is described. Experimental and theoretical results are found to agree satisfactorily.

  19. Drop-out from a psychodynamic group psychotherapy outpatient unit.

    Jensen, Hans Henrik; Mortensen, Erik Lykke; Lotz, Martin


    BACKGROUND. Drop-out from psychotherapy is common and represents a considerable problem in clinical practice and research. Aim. To explore pre-treatment predictors of early and late drop-out from psychodynamic group therapy in a public outpatient unit for non-psychotic disorders in Denmark. Methods. Naturalistic design including 329 patients, the majority with mood, neurotic and personality disorders referred to 39-session group therapy. Predictors were socio-demographic and clinical variables, self-reported symptoms (Symptom Check List-90-Revised) and personality style (Millon Clinical Multiaxial Inventory-II). Drop-out was classified into early and late premature termination excluding patients who dropped out for external reasons. Results. Drop-out comprised 20.6% (68 patients) of the sample. Logistic regression revealed social functioning, vocational training, alcohol problems and antisocial behavior to be related to drop-out. However, early drop-outs had prominent agoraphobic symptoms, lower interpersonal sensitivity and compulsive personality features, and late drop-outs cognitive and somatic anxiety symptoms and antisocial personality features. Clinical and psychological variables accounted for the major part of variance in predictions of drop-out, which ranged from 15.6% to 19.5% (Nagelkerke Pseudo R-Square). Conclusion. Social functioning was consistently associated with drop-out, but personality characteristics and anxiety symptoms differentiated between early and late drop-out. Failure to discriminate between stages of premature termination may explain some of the inconsistencies in the drop-out literature. Clinical implications. Before selection of patients to time-limited psychodynamic groups, self-reported symptoms should be thoroughly considered. Patients with agoraphobic symptoms should be offered alternative treatment. Awareness of and motivation to work with interpersonal issues may be essential for compliance with group therapy.

  20. Student Drop Tower Competitions: Dropping In a Microgravity Environment (DIME) and What If No Gravity? (WING)

    Hall, Nancy R.; Stocker, Dennis P.; DeLombard, Richard


    This paper describes two student competition programs that allow student teams to conceive a science or engineering experiment for a microgravity environment. Selected teams design and build their experimental hardware, conduct baseline tests, and ship their experiment to NASA where it is operated in the 2.2 Second Drop Tower. The hardware and acquired data is provided to the teams after the tests are conducted so that the teams can prepare their final reports about their findings.