Science.gov

Sample records for drop evaporation test

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

    NASA Astrophysics Data System (ADS)

    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

  2. Drop evaporation and triple line dynamics

    NASA Astrophysics Data System (ADS)

    Sobac, Benjamin; Brutin, David; Gavillet, Jerome; Université de Provence Team; Cea Liten Team

    2011-03-01

    Sessile drop evaporation is a phenomenon commonly came across in nature or in industry with cooling, paintings or DNA mapping. However, the evaporation of a drop deposited on a substrate is not completely understood due to the complexity of the problem. Here we investigate, with several nano-coating of the substrate (PTFE, SiOx, SiOc and CF), the influence of the dynamic of the triple line on the evaporation process. The experiment consists in analyzing simultaneously the motion of the triple line, the kinetics of evaporation, the internal thermal motion and the heat and mass transfer. Measurements of temperature, heat-flux and visualizations with visible and infrared cameras are performed. The dynamics of the evaporative heat flux appears clearly different depending of the motion of the triple line

  3. Diffusion Of Mass In Evaporating Multicomponent Drops

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Harstad, Kenneth G.

    1992-01-01

    Report summarizes study of diffusion of mass and related phenomena occurring in evaporation of dense and dilute clusters of drops of multicomponent liquids intended to represent fuels as oil, kerosene, and gasoline. Cluster represented by simplified mathematical model, including global conservation equations for entire cluster and conditions on boundary between cluster and ambient gas. Differential equations of model integrated numerically. One of series of reports by same authors discussing evaporation and combustion of sprayed liquid fuels.

  4. Modeling Evaporation of Drops of Different Kerosenes

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Harstad, Kenneth

    2007-01-01

    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.

  5. Statistical Model of Evaporating Multicomponent Fuel Drops

    NASA Technical Reports Server (NTRS)

    Harstad, Kenneth; LeClercq, Patrick; Bellan, Josette

    2007-01-01

    An improved statistical model has been developed to describe the chemical composition of an evaporating multicomponent- liquid drop and of the mixture of gases surrounding the drop. The model is intended for use in computational simulations of the evaporation and combustion of sprayed liquid fuels, which are typically mixtures of as many as hundreds of different hydrocarbon compounds. The present statistical model is an approximation designed to afford results that are accurate enough to contribute to understanding of the simulated physical and chemical phenomena, without imposing an unduly large computational burden.

  6. Simulations of Evaporating Multicomponent Fuel Drops

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Le Clercq, Patrick

    2005-01-01

    A paper presents additional information on the subject matter of Model of Mixing Layer With Multicomponent Evaporating Drops (NPO-30505), NASA Tech Briefs, Vol. 28, No. 3 (March 2004), page 55. To recapitulate: A mathematical model of a three-dimensional mixing layer laden with evaporating fuel drops composed of many chemical species has been derived. The model is used to perform direct numerical simulations in continuing studies directed toward understanding the behaviors of sprays of liquid petroleum fuels in furnaces, industrial combustors, and engines. The model includes governing equations formulated in an Eulerian and a Lagrangian reference frame for the gas and drops, respectively, and incorporates a concept of continuous thermodynamics, according to which the chemical composition of a fuel is described by use of a distribution function. In this investigation, the distribution function depends solely on the species molar weight. The present paper reiterates the description of the model and discusses further in-depth analysis of the previous results as well as results of additional numerical simulations assessing the effect of the mass loading. The paper reiterates the conclusions reported in the cited previous article, and states some new conclusions. Some new conclusions are: 1. The slower evaporation and the evaporation/ condensation process for multicomponent-fuel drops resulted in a reduced drop-size polydispersity compared to their single-component counterpart. 2. The inhomogeneity in the spatial distribution of the species in the layer increases with the initial mass loading. 3. As evaporation becomes faster, the assumed invariant form of the molecular- weight distribution during evaporation becomes inaccurate.

  7. An evaporation model of multicomponent solution drops

    NASA Astrophysics Data System (ADS)

    Sartori, Silvana; Liñán, Amable; Lasheras, Juan C.

    2010-11-01

    Solutions of polymers are widely used in the pharmaceutical industry as tablets coatings. These allow controlling the rate at which the drug is delivered, taste or appearance. The coating is performed by spraying and drying the tablets at moderate temperatures. The wetting of the coating solution on the pill's surface depends on the droplet Webber and Re numbers, angle of impact and on the rheological properties of the droplet. We present a model for the evaporation of multicomponent solutions droplets in a hot air environment with temperatures substantially lower than the boiling temperature of the solvent. As the liquid vaporizes from the surface the fluid in the drop increases in concentration, until reaching its saturation point. After saturation, precipitation occurs uniformly within the drop. As the surface regresses, a compacting front formed by the precipitate at its maximum packing density advances into the drop, while the solute continues precipitating uniformly. This porous shell grows fast due to the double effect of surface regression and precipitation. The evaporation rate is determined by the rates at which heat is transported to the droplet surface and at which liquid vapor diffuses away from it. When the drop is fully compacted, the evaporation is drastically reduced.

  8. Transient Marangoni convection in hanging evaporating drops

    NASA Astrophysics Data System (ADS)

    Savino, R.; Fico, S.

    2004-10-01

    A combined experimental and numerical analysis has been carried out to study Marangoni effects during the evaporation of droplets. The experiments are performed with pendant drops of silicone oils (with different viscosities) and hydrocarbons. The temperature of the disk sustaining the drop is rapidly increased or decreased in order to study transient heating or cooling processes. The velocity field in the droplet is evaluated monitoring the motion of tracers in the meridian plane, using a laser sheet illumination system and a video camera. Surface temperature distributions of the drops are detected by infrared thermocamera. The numerical model is based on axisymmetric Navier-Stokes equations, taking into account the presence of Marangoni shear stresses and evaporative cooling at the liquid-air interface. Marangoni flows cause a larger, more uniform surface temperature, increasing heat transfer from disk to droplet, as well as evaporation rate. When Marangoni effects are negligible, larger surface temperature differences occur along the drop surface and heat transfer is relatively small. The role of Marangoni and buoyancy flows in silicone oils with different viscosities and hydrocarbons is discussed and correlations are presented between experimental and numerical results.

  9. Effects of Evaporation/Condensation on Spreading and Contact Angle of a Volatile Liquid Drop

    NASA Technical Reports Server (NTRS)

    Zhang, Nengli; Chao, David F.; Singh, Bhim S. (Technical Monitor)

    2000-01-01

    Effects of evaporation/condensation on spreading and contact angle were experimentally studied. A sessile drop of R-113 was tested at different vapor environments to determine the effects of evaporation/condensation on the evolution of contact diameter and contact angle of the drop. Condensation on the drop surface occurs at both the saturated and a nonsaturated vapor environments and promotes the spreading. When the drop is placed in the saturated vapor environment it tends to completely wetting and spreads rapidly. In a nonsaturated vapor environment, the evolution of the sessile drop is divided three stages: condensation-spreading stage, evaporation-retracting stage and rapid contracting stage. In the first stage the drop behaves as in the saturated environment. In the evaporation -retracting stage, the competition between spreading and evaporation of the drop determines the evolution characteristics of the contact diameter and the contact angle. A lower evaporation rate struggles against the spreading power to turn the drop from spreading to retracting with a continuous increase of the contact angle. The drop placed in open air has a much higher evaporation rate. The strong evaporation suppresses the spreading and accelerates the retraction of the drop with a linear decrease of the contact diameter. The contraction of the evaporating drops is gradually accelerated when the contact diameter decreases to 3 min and less till drying up, though the evaporation rate is gradually slowing down.

  10. Evaporation Of Clustered Drops Of Binary-Liquid Fuels

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Harstad, Kenneth G.

    1993-01-01

    Report repeats and elaborates upon information presented in "Diffusion Of Mass In Evaporating Multicomponent Drops" (NPO-18206). Presents details of mathematical model of evaporation of binary liquid from both dense and dilute clusters of drops. Interactions among evaporation, diffusion in liquids, slip velocity, and other phenomena modeled.

  11. Apparent contact angle of an evaporating drop

    NASA Astrophysics Data System (ADS)

    Morris, S. J. S.

    2012-11-01

    In experiments by Poulard et al. (2005), a sessile drop of perfectly wetting liquid evaporates from a non-heated substrate into an under-saturated mixture of vapour with an inert gas; evaporation is limited by vapour diffusion. The system exhibits an apparent contact angle θ that is a flow property. Under certain conditions, the apparent contact line was stationary relative to the substrate; we predict θ for this case. Observed values of θ are small, allowing lubrication analysis of the liquid film. The liquid and vapour flows are coupled through conditions holding at the phase interface; in particular, vapour partial pressure there is related to the local value of liquid pressure through the Kelvin condition. Because the droplet is shallow, the interfacial conditions can be transferred to the solid-liquid interface at y = 0 . We show that the dimensionless partial pressure p (x , y) and the film thickness h (x) are determined by solving ∇2 p = 0 for y > 0 subject to a matching condition at infinity, and the conditions - p = L hxx +h-3 and (h3px) x + 3py = 0 at y = 0 . The parameter L controls the ratio of Laplace to disjoining pressure. We analyse this b.v.p. for the experimentally-relevant case L --> 0 .

  12. PROGRAM DROP: A computer program for prediction of evaporation from freely falling multicomponent drops

    SciTech Connect

    Gavin, P.M.

    1996-12-01

    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.

  13. Building micro-soccer-balls with evaporating colloidal fakir drops

    NASA Astrophysics Data System (ADS)

    Gelderblom, Hanneke; Marín, Álvaro G.; Susarrey-Arce, Arturo; van Housselt, Arie; Lefferts, Leon; Gardeniers, Han; Lohse, Detlef; Snoeijer, Jacco H.

    2013-11-01

    Drop evaporation can be used to self-assemble particles into three-dimensional microstructures on a scale where direct manipulation is impossible. We present a unique method to create highly-ordered colloidal microstructures in which we can control the amount of particles and their packing fraction. To this end, we evaporate colloidal dispersion drops from a special type of superhydrophobic microstructured surface, on which the drop remains in Cassie-Baxter state during the entire evaporative process. The remainders of the drop consist of a massive spherical cluster of the microspheres, with diameters ranging from a few tens up to several hundreds of microns. We present scaling arguments to show how the final particle packing fraction of these balls depends on the drop evaporation dynamics, particle size, and number of particles in the system.

  14. Analysis of the convective evaporation of nondilute clusters of drops

    NASA Technical Reports Server (NTRS)

    Bellan, J.; Harstad, K.

    1987-01-01

    The penetration distance of an outer flow into a drop cluster volume is the critical, evaporation mode-controlling parameter in the present model for nondilute drop clusters' convective evaporation. The model is found to perform well for such low penetration distances as those obtained for dense clusters in hot environments and low relative velocities between the outer gases and the cluster. For large penetration distances, however, the predictive power of the model deteriorates; in addition, the evaporation time is found to be a weak function of the initial relative velocity and a strong function of the initial drop temperature. The results generally show that the interior drop temperature was transient throughout the drop lifetime, although temperature nonuniformities persisted up to the first third of the total evaporation time at most.

  15. Flow visualization and characterization of evaporating liquid drops

    NASA Technical Reports Server (NTRS)

    Chao, David F. (Inventor); Zhang, Nengli (Inventor)

    2004-01-01

    An optical system, consisting of drop-reflection image, reflection-refracted shadowgraphy and top-view photography, is used to measure the spreading and instant dynamic contact angle of a volatile-liquid drop on a non-transparent substrate. The drop-reflection image and the shadowgraphy is shown by projecting the images of a collimated laser beam partially reflected by the drop and partially passing through the drop onto a screen while the top view photograph is separately viewed by use of a camera video recorder and monitor. For a transparent liquid on a reflective solid surface, thermocapillary convection in the drop, induced by evaporation, can be viewed nonintrusively, and the drop real-time profile data are synchronously recorded by video recording systems. Experimental results obtained from this technique clearly reveal that evaporation and thermocapillary convection greatly affect the spreading process and the characteristics of dynamic contact angle of the drop.

  16. Flash evaporator systems test

    NASA Technical Reports Server (NTRS)

    Dietz, J. B.

    1976-01-01

    A flash evaporator heat rejection system representative of that proposed for the space shuttle orbiter underwent extensive system testing at the NASA Johnson Space Center (JSC) to determine its operational suitability and to establish system performance/operational characteristics for use in the shuttle system. During the tests the evaporator system demonstrated its suitability to meet the shuttle requirements by: (1) efficient operation with 90 to 95% water evaporation efficiency, (2) control of outlet temperature to 40 + or - 2 F for partial heat load operation, (3) stability of control system for rapid changes in Freon inlet temperature, and (4) repeated dormant-to-active device operation without any startup procedures.

  17. The evaporation of a drop in strongly superheated steam

    NASA Astrophysics Data System (ADS)

    Stasenko, A. L.; Shapshal, I. B.

    1983-10-01

    By comparing the numerical solutions to the model systems of equations of the dynamics and mass and heat transfer of a spherical drop, criterial relationships are obtained for the resistance coefficient and Nusselt and Sherwood numbers in the Reynolds number range up to 1000 for vapor/drop temperature ratios up to 4. The relationships obtained are used to calculate the length and time of the complete evaporation of nitrogen drops in nitrogen gas. It is found that the curve describing the dependence of the complete evaporation length of large (in the mm range) drops on the vapor temperature has a minimum. The origin of the minimum is examined.

  18. Large Eddy Simulation of jets laden with evaporating drops

    NASA Technical Reports Server (NTRS)

    Leboissetier, A.; Okong'o, N.; Bellan, J.

    2004-01-01

    LES of a circular jet laden with evaporating liquid drops are conducted to assess computational-drop modeling and three different SGS-flux models: the Scale Similarity model (SSC), using a constant coefficient calibrated on a temporal mixing layer DNS database, and dynamic-coefficient Gradient and Smagorinsky models.

  19. Measurement of an Evaporating Drop on a Reflective Substrate

    NASA Technical Reports Server (NTRS)

    Chao, David F.; Zhang, Nengli

    2004-01-01

    A figure depicts an apparatus that simultaneously records magnified ordinary top-view video images and laser shadowgraph video images of a sessile drop on a flat, horizontal substrate that can be opaque or translucent and is at least partially specularly reflective. The diameter, contact angle, and rate of evaporation of the drop as functions of time can be calculated from the apparent diameters of the drop in sequences of the images acquired at known time intervals, and the shadowgrams that contain flow patterns indicative of thermocapillary convection (if any) within the drop. These time-dependent parameters and flow patterns are important for understanding the physical processes involved in the spreading and evaporation of drops. The apparatus includes a source of white light and a laser (both omitted from the figure), which are used to form the ordinary image and the shadowgram, respectively. Charge-coupled-device (CCD) camera 1 (with zoom) acquires the ordinary video images, while CCD camera 2 acquires the shadowgrams. With respect to the portion of laser light specularly reflected from the substrate, the drop acts as a plano-convex lens, focusing the laser beam to a shadowgram on the projection screen in front of CCD camera 2. The equations for calculating the diameter, contact angle, and rate of evaporation of the drop are readily derived on the basis of Snell s law of refraction and the geometry of the optics.

  20. Surfactant-Enhanced Benard Convection on an Evaporating Drop

    NASA Astrophysics Data System (ADS)

    Nguyen, Van X.; Stebe, Kathleen J.

    2001-11-01

    Surfactant effects on an evaporating drop are studied experimentally. Using a fluorescent probe, the distribution and surface phase of the surfactant is directly imaged throughout the evaporation process. From these experiments, we identify conditions in which surfactants promote surface tension-driven Benard instabilities in aqueous systems. The drops under study contain finely divided particles, which act as tracers in the flow, and form well-defined patterns after the drop evaporates. Two flow fields have been reported in this system. The first occurs because the contact line becomes pinned by solid particles at the contact line region. In order for the contact line to remain fixed, an outward flow toward the ring results, driving further accumulation at the contact ring. A ‘coffee ring’ of particles is left as residue after the drop evaporates[1]. The second flow is Benard convection, driven by surface tension gradients on the drop[2,3]. In our experiments, an insoluble monolayer of pentadecanoic acid is spread at the interface of a pendant drop. The surface tension is recorded, and the drop is deposited on a well-defined solid substrate. Fluorescent images of the surface phase of the surfactant are recorded as the drop evaporates. The surfactant monolayer assumes a variety of surface states as a function of the area per molecule at the interface: surface gaseous, surface liquid expanded, and surface liquid condensed phases[4]. Depending upon the surface state of the surfactant as the drop evaporates, transitions of residue patterns left by the particles occur, from the coffee ring pattern to Benard cells to irregular patterns, suggesting a strong resistance to outward flow are observed. The occurrence of Benard cells on a surfactant-rich interface occurs when the interface is in LE-LC coexistence. Prior research concerning surfactant effects on this instability predict that surfactants are strongly stabilizing[5]. The mechanisms for this change in behavior

  1. Evaporation Of Clusters Of Drops In A Jet

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Harstad, Kenneth G.

    1993-01-01

    Report presents theoretical study of evaporation of clusters of liquid drops injected with gas jet flowing into hot ambient gas. One in series of studies of various aspects of behavior of sprays. Simplified mathematical models used to extract qualitative information on trends in interactions.

  2. Model of Mixing Layer With Multicomponent Evaporating Drops

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Le Clercq, Patrick

    2004-01-01

    A mathematical model of a three-dimensional mixing layer laden with evaporating fuel drops composed of many chemical species has been derived. The study is motivated by the fact that typical real petroleum fuels contain hundreds of chemical species. Previously, for the sake of computational efficiency, spray studies were performed using either models based on a single representative species or models based on surrogate fuels of at most 15 species. The present multicomponent model makes it possible to perform more realistic simulations by accounting for hundreds of chemical species in a computationally efficient manner. The model is used to perform Direct Numerical Simulations in continuing studies directed toward understanding the behavior of liquid petroleum fuel sprays. The model includes governing equations formulated in an Eulerian and a Lagrangian reference frame for the gas and the drops, respectively. This representation is consistent with the expected volumetrically small loading of the drops in gas (of the order of 10 3), although the mass loading can be substantial because of the high ratio (of the order of 103) between the densities of liquid and gas. The drops are treated as point sources of mass, momentum, and energy; this representation is consistent with the drop size being smaller than the Kolmogorov scale. Unsteady drag, added-mass effects, Basset history forces, and collisions between the drops are neglected, and the gas is assumed calorically perfect. The model incorporates the concept of continuous thermodynamics, according to which the chemical composition of a fuel is described probabilistically, by use of a distribution function. Distribution functions generally depend on many parameters. However, for mixtures of homologous species, the distribution can be approximated with acceptable accuracy as a sole function of the molecular weight. The mixing layer is initially laden with drops in its lower stream, and the drops are colder than the gas

  3. Structural and evaporative evolutions in desiccating sessile drops of blood

    NASA Astrophysics Data System (ADS)

    Sobac, B.; Brutin, D.

    2011-07-01

    We report an experimental investigation of the drying of a deposited drop of whole blood. Flow motion, adhesion, gelation, and fracturation all occur during the evaporation of this complex matter, leading to a final typical pattern. Two distinct regimes of evaporation are highlighted: the first is driven by convection, diffusion, and gelation in a liquid phase, whereas the second, with a much slower rate of evaporation, is characterized by the mass transport of the liquid left over in the gellified biocomponent matter. A diffusion model of the drying process allows a prediction of the transition between these two regimes of evaporation. Moreover, the formation of cracks and other events occurring during the drying are examined and shown to be driven by critical solid mass concentrations.

  4. Drop evaporation in a single-axis acoustic levitator

    NASA Technical Reports Server (NTRS)

    Lierke, E. G.; Croonquist, A. P.

    1990-01-01

    A 20 kHz single-axis acoustic positioner is used to levitate aqueous-solution drops (volumes less than or approximately equal to 100 micro-liters). Drop evaporation rates are measured under ambient, isothermal conditions for different relative humidities. Acoustic convection around the levitated sample enhances the mass loss over that due to natural convection and diffusion. A theoretical treatment of the mass flow is developed in analogy to previous studies of the heat transfer from a sphere in an acoustic field. Predictions of the enhanced mass loss, in the form of Nusselt (Sherwood) numbers, are compared with observed rages of drop shrinking. The work is part of an ESA crystal growth from levitated solution drops.

  5. Evaporation-triggered microdroplet nucleation and the four life phases of an evaporating Ouzo drop.

    PubMed

    Tan, Huanshu; Diddens, Christian; Lv, Pengyu; Kuerten, J G M; Zhang, Xuehua; Lohse, Detlef

    2016-08-01

    Evaporating liquid droplets are omnipresent in nature and technology, such as in inkjet printing, coating, deposition of materials, medical diagnostics, agriculture, the food industry, cosmetics, or spills of liquids. Whereas the evaporation of pure liquids, liquids with dispersed particles, or even liquid mixtures has intensively been studied over the past two decades, the evaporation of ternary mixtures of liquids with different volatilities and mutual solubilities has not yet been explored. Here we show that the evaporation of such ternary mixtures can trigger a phase transition and the nucleation of microdroplets of one of the components of the mixture. As a model system, we pick a sessile Ouzo droplet (as known from daily life-a transparent mixture of water, ethanol, and anise oil) and reveal and theoretically explain its four life phases: In phase I, the spherical cap-shaped droplet remains transparent while the more volatile ethanol is evaporating, preferentially at the rim of the drop because of the singularity there. This leads to a local ethanol concentration reduction and correspondingly to oil droplet nucleation there. This is the beginning of phase II, in which oil microdroplets quickly nucleate in the whole drop, leading to its milky color that typifies the so-called "Ouzo effect." Once all ethanol has evaporated, the drop, which now has a characteristic nonspherical cap shape, has become clear again, with a water drop sitting on an oil ring (phase III), finalizing the phase inversion. Finally, in phase IV, all water has evaporated, leaving behind a tiny spherical cap-shaped oil drop. PMID:27418601

  6. Vaporization response of evaporating drops with finite thermal conductivity

    NASA Technical Reports Server (NTRS)

    Agosta, V. D.; Hammer, S. S.

    1975-01-01

    A numerical computing procedure was developed for calculating vaporization histories of evaporating drops in a combustor in which travelling transverse oscillations occurred. The liquid drop was assumed to have a finite thermal conductivity. The system of equations was solved by using a finite difference method programmed for solution on a high speed digital computer. Oscillations in the ratio of vaporization of an array of repetitivity injected drops in the combustor were obtained from summation of individual drop histories. A nonlinear in-phase frequency response factor for the entire vaporization process to oscillations in pressure was evaluated. A nonlinear out-of-phase response factor, in-phase and out-of-phase harmonic response factors, and a Princeton type 'n' and 'tau' were determined. The resulting data was correlated and is presented in graphical format. Qualitative agreement with the open literature is obtained in the behavior of the in-phase response factor. Quantitatively the results of the present finite conductivity spray analysis do not correlate with the results of a single drop model.

  7. Evaporation of pure liquid sessile and spherical suspended drops: a review.

    PubMed

    Erbil, H Yildirim

    2012-01-15

    A sessile drop is an isolated drop which has been deposited on a solid substrate where the wetted area is limited by a contact line and characterized by contact angle, contact radius and drop height. Diffusion-controlled evaporation of a sessile drop in an ambient gas is an important topic of interest because it plays a crucial role in many scientific applications such as controlling the deposition of particles on solid surfaces, in ink-jet printing, spraying of pesticides, micro/nano material fabrication, thin film coatings, biochemical assays, drop wise cooling, deposition of DNA/RNA micro-arrays, and manufacture of novel optical and electronic materials in the last decades. This paper presents a review of the published articles for a period of approximately 120 years related to the evaporation of both sessile drops and nearly spherical droplets suspended from thin fibers. After presenting a brief history of the subject, we discuss the basic theory comprising evaporation of micrometer and millimeter sized spherical drops, self cooling on the drop surface and evaporation rate of sessile drops on solids. The effects of drop cooling, resultant lateral evaporative flux and Marangoni flows on evaporation rate are also discussed. This review also has some special topics such as drop evaporation on superhydrophobic surfaces, determination of the receding contact angle from drop evaporation, substrate thermal conductivity effect on drop evaporation and the rate evaporation of water in liquid marbles. PMID:22277832

  8. DWPF Recycle Evaporator Simulant Tests

    SciTech Connect

    Stone, M

    2005-04-05

    Testing was performed to determine the feasibility and processing characteristics of an evaporation process to reduce the volume of the recycle stream from the Defense Waste Processing Facility (DWPF). The concentrated recycle would be returned to DWPF while the overhead condensate would be transferred to the Effluent Treatment Plant. Various blends of evaporator feed were tested using simulants developed from characterization of actual recycle streams from DWPF and input from DWPF-Engineering. The simulated feed was evaporated in laboratory scale apparatus to target a 30X volume reduction. Condensate and concentrate samples from each run were analyzed and the process characteristics (foaming, scaling, etc) were visually monitored during each run. The following conclusions were made from the testing: Concentration of the ''typical'' recycle stream in DWPF by 30X was feasible. The addition of DWTT recycle streams to the typical recycle stream raises the solids content of the evaporator feed considerably and lowers the amount of concentration that can be achieved. Foaming was noted during all evaporation tests and must be addressed prior to operation of the full-scale evaporator. Tests were conducted that identified Dow Corning 2210 as an antifoam candidate that warrants further evaluation. The condensate has the potential to exceed the ETP WAC for mercury, silicon, and TOC. Controlling the amount of equipment decontamination recycle in the evaporator blend would help meet the TOC limits. The evaporator condensate will be saturated with mercury and elemental mercury will collect in the evaporator condensate collection vessel. No scaling on heating surfaces was noted during the tests, but splatter onto the walls of the evaporation vessels led to a buildup of solids. These solids were difficult to remove with 2M nitric acid. Precipitation of solids was not noted during the testing. Some of the aluminum present in the recycle streams was converted from gibbsite to

  9. Evaporation of drops on two parallel fibers: influence of the liquid morphology and fiber elasticity.

    PubMed

    Duprat, Camille; Bick, Alison D; Warren, Patrick B; Stone, Howard A

    2013-06-25

    We investigate experimentally the evaporation of liquid accumulated on a pair of parallel fibers, rigid or flexible. The liquid wetting the fibers can adopt two distinct morphologies: a compact drop shape, whose evaporation dynamics is similar to that of an isolated aerosol droplet, or a long liquid column of constant cross-section, whose evaporation dynamics depends upon the aspect ratio of the column. We thus find that the evaporation rate is constant for drops, while it increases strongly for columns as the interfiber distance decreases, and we propose a model to explain this behavior. When the fibers are flexible, the transition from drops to columns can be induced by the deformation of the fibers because of the capillary forces applied by the drop. Thus, we find that the evaporation rate increases with increasing flexibility. Furthermore, complex morphology transitions occur upon drying, which results in spreading of the drop as it evaporates. PMID:23705986

  10. Effect of the Heat Flux Density on the Evaporation Rate of a Distilled Water Drop

    NASA Astrophysics Data System (ADS)

    Ponomarev, Konstantin; Orlova, Evgeniya; Feoktistov, Dmitry

    2016-02-01

    This paper presents the experimental dependence of the evaporation rate of a nondeaerated distilled water drop from the heat flux density on the surfaces of non-ferrous metals (copper and brass). A drop was placed on a heated substrate by electronic dosing device. To obtain drop profile we use a shadow optical system; drop symmetry was controlled by a high-speed video camera. It was found that the evaporation rate of a drop on a copper substrate is greater than on a brass. The evaporation rate increases intensively with raising volume of a drop. Calculated values of the heat flux density and the corresponding evaporation rates are presented in this work. The evaporation rate is found to increase intensively on the brass substrate with raising the heat flux density.

  11. Effect of relative humidity on contact angle of inkjet-printed evaporating colloidal drops

    NASA Astrophysics Data System (ADS)

    Chhasatia, Viral; Joshi, Abhijit; Sun, Ying

    2010-11-01

    The deposition behavior of inkjet-printed aqueous colloidal drops onto glass and polymer (PEN and PET) substrates has been investigated by using fluorescence microscopy, a high-resolution CCD camera, and scanning electron microscopy. Real-time side-view images show that the contact angle of an evaporating colloidal drop is a function of the ambient humidity. The relative humidity also affects the extent to which the drop is able to spread after impacting a substrate, the evaporation rate at the drop surface, and the evaporatively-driven flow inside the drop that drives the suspended particles towards the contact line. The difference between the contact line velocity and liquid velocity at the drop contact line induced by evaporation creates a larger contact angle compared to that of the case without evaporation. This increase in contact angle becomes more significant for a low ambient humidity. Results also show that the particle deposition area and pattern change with the ambient humidity.

  12. 49 CFR 178.965 - Drop test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Drop test. 178.965 Section 178.965 Transportation... Packagings § 178.965 Drop test. (a) General. The drop test must be conducted for the qualification of all...) Special preparation for the drop test. Large Packagings must be filled in accordance with § 178.960....

  13. 49 CFR 178.1045 - Drop test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Drop test. 178.1045 Section 178.1045... Containers § 178.1045 Drop test. (a) General. The drop test must be conducted for the qualification of all... subpart. (b) Special preparation for the drop test. Flexible Bulk Containers must be filled to...

  14. 49 CFR 178.810 - Drop test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Drop test. 178.810 Section 178.810 Transportation... Drop test. (a) General. The drop test must be conducted for the qualification of all IBC design types... the drop test. (1) Metal, rigid plastic, and composite IBCs intended to contain solids must be...

  15. 49 CFR 178.603 - Drop test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Drop test. 178.603 Section 178.603 Transportation... Packagings and Packages § 178.603 Drop test. (a) General. The drop test must be conducted for the... than flat drops, the center of gravity of the test packaging must be vertically over the point...

  16. Investigation of interfacial phenomena and thermocapillary effect on drop evaporation in reduced gravity condition

    NASA Astrophysics Data System (ADS)

    Xie, Jingchang; Lin, Hai

    2013-11-01

    Based on ground-based experiments, a drop evaporation experiment will fly aboard Chinese recoverable satellite in the near future This experiment will focus on the interfacial phenomena of phase chance, heat and mass transfer and the effect of thermocapillary convection on drop evaporation process Close attention will also be paid to the contact angle behavior, the triple line shifting and their relations Our ground-based experiments observed the interior flow field and the gaseous exterior of small suspended evaporating drops, the temperature distributions inside and outside the drops. Both good heat conductor and heat insulating material were used as substrate materials to investigate their influence on heat transfer and surface temperature distribution of an evaporating drop Experimental results indicate that for a drop evaporating in ambient temperature without substrate heating, temperature gradients existed along the drop surface which results in stable thermocapillary convection and cells appeared near the surface throughout entire evaporating process. The thermocapillary convection greatly changed drop's interior temperature distribution and the way of energy and mass transfer. Temperature jump or discontinuity was also measured at drop free surface.

  17. Mobile evaporator corrosion test results

    SciTech Connect

    Rozeveld, A.; Chamberlain, D.B.

    1997-05-01

    Laboratory corrosion tests were conducted on eight candidates to select a durable and cost-effective alloy for use in mobile evaporators to process radioactive waste solutions. Based on an extensive literature survey of corrosion data, three stainless steel alloys (304L, 316L, AL-6XN), four nickel-based alloys (825, 625, 690, G-30), and titanium were selected for testing. The corrosion tests included vapor phase, liquid junction (interface), liquid immersion, and crevice corrosion tests on plain and welded samples of candidate materials. Tests were conducted at 80{degrees}C for 45 days in two different test solutions: a nitric acid solution. to simulate evaporator conditions during the processing of the cesium ion-exchange eluant and a highly alkaline sodium hydroxide solution to simulate the composition of Tank 241-AW-101 during evaporation. All of the alloys exhibited excellent corrosion resistance in the alkaline test solution. Corrosion rates were very low and localized corrosion was not observed. Results from the nitric acid tests showed that only 316L stainless steel did not meet our performance criteria. The 316L welded interface and crevice specimens had rates of 22.2 mpy and 21.8 mpy, respectively, which exceeds the maximum corrosion rate of 20 mpy. The other welded samples had about the same corrosion resistance as the plain samples. None of the welded samples showed preferential weld or heat-affected zone (HAZ) attack. Vapor corrosion was negligible for all alloys. All of the alloys except 316L exhibited either {open_quotes}satisfactory{close_quotes} (2-20 mpy) or {open_quotes}excellent{close_quotes} (<2 mpy) corrosion resistance as defined by National Association of Corrosion Engineers. However, many of the alloys experienced intergranular corrosion in the nitric acid test solution, which could indicate a susceptibility to stress corrosion cracking (SCC) in this environment.

  18. Evaporation Flux Distribution of Drops on a Hydrophilic or Hydrophobic Flat Surface by Molecular Simulations.

    PubMed

    Xie, Chiyu; Liu, Guangzhi; Wang, Moran

    2016-08-16

    The evaporation flux distribution of sessile drops is investigated by molecular dynamic simulations. Three evaporating modes are classified, including the diffusion dominant mode, the substrate heating mode, and the environment heating mode. Both hydrophilic and hydrophobic drop-substrate interactions are considered. To count the evaporation flux distribution, which is position dependent, we proposed an azimuthal-angle-based division method under the assumption of spherical crown shape of drops. The modeling results show that the edge evaporation, i.e., near the contact line, is enhanced for hydrophilic drops in all the three modes. The surface diffusion of liquid molecular absorbed on solid substrate for hydrophilic cases plays an important role as well as the space diffusion on the enhanced evaporation rate at the edge. For hydrophobic drops, the edge evaporation flux is higher for the substrate heating mode, but lower than elsewhere of the drop for the diffusion dominant mode; however, a nearly uniform distribution is found for the environment heating mode. The evidence shows that the temperature distribution inside drops plays a key role in the position-dependent evaporation flux. PMID:27441759

  19. Thermocapillary instabilities in an evaporating drop deposited onto a heated substrate

    NASA Astrophysics Data System (ADS)

    Sobac, B.; Brutin, D.

    2012-03-01

    The present study is an experimental investigation regarding the evaporation of ethanol drops deposited onto a heated substrate in a partial wetting situation. The originality of this work is based on the simultaneous observation of the kinetics of evaporation, heat and mass transfers, the triple-line dynamic, and thermal motions inside the drop. The triple line recedes during the drop evaporation and a spontaneous development of thermal-convective instabilities driven by the evaporation are observed. These instabilities are interpreted as hydrothermal waves induced by surface tension gradient along the free surface. An infrared technique is used to investigate the temporal and spatial dynamics of the hydrothermal waves. Results reveal a non-linear evolution of the number of waves as well as several instability regimes. A complete description of the drop evaporation with the evidence of several phases is provided. The influence of geometrical and thermal parameters has been analyzed and raised scaling laws on hydrodynamic and energy transport. The drop evaporation appears to be characterized by a constant drop Nusselt number of a value 1.7 during all the process which highlights both the importance of conduction and convection in the energy transport in an evaporating drop.

  20. Evaporation and fluid dynamics of a sessile drop of capillary size.

    SciTech Connect

    Barash, L. Yu.; Bigioni, T. P.; Vinokur, V. M.; Shchur, L. N.; Materials Science Division; Landau Inst. for Theoretical Physics; Univ. of Chicago

    2009-01-01

    Theoretical description and numerical simulation of an evaporating sessile drop are developed. 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. A shape of the rotationally symmetric drop is determined within the quasistationary approximation. Nonstationary effects in the diffusion of the vapor are also taken into account. Simulation results agree well with the data of evaporation rate measurements for the toluene drop. Marangoni forces associated with the temperature dependence of the surface tension generate fluid convection in the sessile drop. Our results demonstrate several dynamical stages of the convection characterized by different number of vortices in the drop. During the early stage the array of vortices arises near a surface of the drop and induces a nonmonotonic spatial distribution of the temperature over the drop surface. The initial number of near-surface vortices in the drop is controlled by the Marangoni cell size which is similar to that given by Pearson for flat fluid layers. This number quickly decreases with time resulting in three bulk vortices in the intermediate stage. The vortices finally transform into the single convection vortex in the drop existing during about 1/2 of the evaporation time.

  1. Experimental investigation of liquid drop evaporation on a heated solid surface

    NASA Astrophysics Data System (ADS)

    Semenov, A. A.; Feoktistov, D. V.; Zaitsev, D. V.; Kuznetsov, G. V.; Kabov, O. A.

    2015-11-01

    Evaporation of a water drop was studied experimentally at a temperature difference between the solid surface and surrounding atmosphere from 30 to 60 °C. The studies were performed on the substrates with micro- and nanocoatings with different wettability. The features of evaporation were studied for the pinned, partially pinned, and depinned three-phase contact line (solid-liquid-gas interface). It is shown that with a decrease in the water drop volume, the specific evaporation rate (mass flow per unit of surface area) increases, particularly at the last stage of evaporation.

  2. Convective rolls and hydrothermal waves in evaporating sessile drops.

    PubMed

    Karapetsas, George; Matar, Omar K; Valluri, Prashant; Sefiane, Khellil

    2012-08-01

    Recent experiments on the evaporation of sessile droplets have revealed the spontaneous formation of various patterns including the presence of hydrothermal waves. These waves had previously been observed, in the absence of evaporation, in thin liquid layers subjected to an imposed, uniform temperature gradient. This is in contrast to the evaporating droplet case wherein these gradients arise naturally due to evaporation and are spatially and temporally varying. In the present paper, we present a theory of evaporating sessile droplets deposited on a heated surface and propose a candidate mechanism for the observed pattern formation using a linear stability analysis in the quasi-steady-state approximation. A qualitative agreement with experimental trends is observed. PMID:22775413

  3. 49 CFR 572.102 - Drop test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Drop test. 572.102 Section 572.102 Transportation..., DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Free Motion Headform § 572.102 Drop test. (a) When the headform is dropped from a height of 14.8 inches in accordance with paragraph (b)...

  4. 49 CFR 572.102 - Drop test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Drop test. 572.102 Section 572.102 Transportation..., DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Free Motion Headform § 572.102 Drop test. (a) When the headform is dropped from a height of 14.8 inches in accordance with paragraph (b)...

  5. 49 CFR 572.102 - Drop test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 7 2012-10-01 2012-10-01 false Drop test. 572.102 Section 572.102 Transportation..., DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Free Motion Headform § 572.102 Drop test. (a) When the headform is dropped from a height of 14.8 inches in accordance with paragraph (b)...

  6. Triple-line behavior and wettability controlled by nanocoated substrates: influence on sessile drop evaporation.

    PubMed

    Sobac, B; Brutin, D

    2011-12-20

    In this article, we investigate the influence of the surface properties of substrates on the evaporation process. Using various nanocoatings, it is possible to modify the surface properties of substrates, such as the roughness and the surface energy, while maintaining constant thermal properties. Experiments are conducted under atmospheric conditions with five fluids (methanol, ethanol, propanol, toluene and water) and four coatings (PFC, PTFE, SiOC, and SiO(x)). The various combinations of these fluids and coatings allow for a wide range of drop evaporation properties to be studied: the dynamics of the triple line, the volatility of fluids, and a large range of wettabilities (from 17 to 135°). The experimental data are in very good quantitative agreement with existing models of quasi-steady, diffusion-driven evaporation. The experimental results show that the dynamics of the evaporative rate are proportional to the dynamics of the wetting radius. Thus, the models succeed in describing the evaporative dynamics throughout the evaporation process regardless of the behavior of the triple line. Moreover, the use of various liquids reveals the validity of the models regardless of their volatility. The results also confirm the recent finding of a universal relation for the time evolution of the drop mass, independent of the drop size and initial contact angle. Finally, this study highlights the separate and coupled roles of the triple line and the wettability on the sessile drop evaporation process. Data reveal that the more wet and pinned a drop, the shorter the evaporation time. PMID:22054245

  7. Irreversible entropy production in two-phase flows with evaporating drops

    NASA Technical Reports Server (NTRS)

    Bellan, J.; Okong'o, N. A.

    2002-01-01

    A derivation of the irreversible entropy production, that is the dissipation, in two-phase flows is presented for the purpose of examining the effect of evaporative-drop modulation of flows having turbulent features.

  8. Evaporative oxidation treatability test report

    SciTech Connect

    1995-04-01

    In 1992, Congress passed the Federal Facilities Compliance Act that requires the U.S. Department of Energy (DOE) to treat and dispose of its mixed waste in accordance with the Resource Conservation and Recovery Act (RCRA) land disposal restrictions (LDRs). In response to the need for mixed-waste treatment capacity where available off-site commercial treatment facilities do not exist or cannot be used, the DOE Albuquerque Operations Office (DOE-AL) organized a Treatment Selection Team to match mixed wastes with treatment options and develop a strategy for treatment of its mixed wastes. DOE-AL manages operations at nine sites with mixed-waste inventories. The Treatment Selection Team determined a need to develop mobile treatment capacity to treat wastes at the sites where the wastes are generated. Treatment processes used for mixed waste not only must address the hazardous component (i.e., meet LDRs) but also must contain the radioactive component in a form that allows final disposal while protecting workers, the public, and the environment. On the basis of recommendations of the Treatment Selection Team, DOE-AL assigned projects to the sites to bring mixed-waste treatment capacity on-line. The three technologies assigned to the DOE Grand Junction Projects Office (GJPO) are evaporative oxidation, thermal desorption, and treated wastewater evaporation. Rust Geotech, the DOE-GJPO prime contractor, was assigned to design and fabricate mobile treatment units (MTUs) for these three technologies and to deliver the MTUs to selected DOE-AL sites. To conduct treatability tests at the GJPO, Rust leased a pilot-scale evaporative oxidation unit from the Clemson Technical Center (CTC), Anderson, South Carolina. The purpose of this report is to document the findings and results of tests performed using this equipment.

  9. Self-assembly of nanoparticles in evaporating particle-laden emulsion drops

    NASA Astrophysics Data System (ADS)

    Pack, Min; Yang, Xin; Sun, Ying

    2014-11-01

    In this study, we demonstrate the scalable fabrication of nanostructures (e.g., nanomesh and nanoring arrays) via inkjet printing of oil-in-water emulsion drops containing nanoparticles in water. Nanoscale oil drops dispersed in water are used here as templates for assembly of nanoparticles on a substrate. The effect of oil vapor pressure on particle deposition morphologies is studied by using a variety of oils. For oil drops with a lower vapor pressure, non-uniform evaporation rate along the air-water interface drives dispersed oil drops to move and accumulate near the air/water/substrate contact line. These oil drops remain on the substrate while water is evaporating enabling nanoparticles to self-assemble into nanomeshes. While keeping the same oil concentration, oil drops with a higher vapor pressure completely evaporates near the contact line before water dries out, leading to nanoparticle deposition of coffee-ring structures. If nanoparticles are confined inside the dispersed oil drops, nanoring arrays are formed as the emulsion evaporates. The characteristics of the nanomeshes and nanorings are controlled by tuning the size and concentration of oil drops and nanoparticles, substrate wettability, surfactant concentration, and vapor pressure of oil.

  10. Control of stain geometry by drop evaporation of surfactant containing dispersions.

    PubMed

    Erbil, H Yildirim

    2015-08-01

    Control of stain geometry by drop evaporation of surfactant containing dispersions is an important topic of interest because it plays a crucial role in many applications such as forming templates on solid surfaces, in ink-jet printing, spraying of pesticides, micro/nano material fabrication, thin film coatings, biochemical assays, deposition of DNA/RNA micro-arrays, and manufacture of novel optical and electronic materials. This paper presents a review of the published articles on the diffusive drop evaporation of pure liquids (water), the surfactant stains obtained from evaporating drops that do not contain dispersed particles and deposits obtained from drops containing polymer colloids and carbon based particles such as carbon nanotubes, graphite and fullerenes. Experimental results of specific systems and modeling attempts are discussed. This review also has some special subtopics such as suppression of coffee-rings by surfactant addition and "stick-slip" behavior of evaporating nanosuspension drops. In general, the drop evaporation process of a surfactant/particle/substrate system is very complex since dissolved surfactants adsorb on both the insoluble organic/inorganic micro/nanoparticles in the drop, on the air/solution interface and on the substrate surface in different extends. Meanwhile, surfactant adsorbed particles interact with the substrate giving a specific contact angle, and free surfactants create a solutal Marangoni flow in the drop which controls the location of the particle deposition together with the rate of evaporation. In some cases, the presence of a surfactant monolayer at the air/solution interface alters the rate of evaporation. At present, the magnitude of each effect cannot be predicted adequately in advance and consequently they should be carefully studied for any system in order to control the shape and size of the final deposit. PMID:25217332

  11. Diffusion-controlled evaporation of sodium dodecyl sulfate solution drops placed on a hydrophobic substrate.

    PubMed

    Doganci, Merve Dandan; Sesli, Belma Uyar; Erbil, H Yildirim

    2011-10-15

    In this work, the effect of SDS anionic surfactant on the diffusion-controlled evaporation rate of aqueous solution drops placed on TEFLON-FEP substrate was investigated with 11 different SDS concentrations. Drop evaporation was monitored in a closed chamber having a constant RH of 54-57% by a video camera. The initial contact angle, θ(i) decreased from 104±2° down to 68±1° due to the adsorption of SDS both at the water-air and the solid-water interfaces. The adsorption of SDS on the solid surface was found to be 76% of that of its adsorption at the water-air interface by applying Lucassen-Reynders approach. An equation was developed for the comparison of the evaporation rates of drops having different θ(i) on the same substrate. It was found that the addition of SDS did not alter the drop evaporation rate considerably for the first 1200 s for all the SDS concentrations. The main difference was found to be the change of the mode of drop evaporation by varying the SDS concentration. The constant θ mode was operative up to 80 mM SDS concentration, whereas constant contact area mode was operative after 200 mM SDS concentrations due to rapid drop pining on the substrate. PMID:21784429

  12. Simulation of evaporation of a sessile drop using a diffuse interface model

    NASA Astrophysics Data System (ADS)

    Sefiane, Khellil; Ding, Hang; Sahu, Kirti; Matar, Omar

    2008-11-01

    We consider here the evaporation dynamics of a Newtonian liquid sessile drop using an improved diffuse interface model. The governing equations for the drop and surrounding vapour are both solved, and separated by the order parameter (i.e. volume fraction), based on the previous work of Ding et al. JCP 2007. The diffuse interface model has been shown to be successful in modelling the moving contact line problems (Jacqmin 2000; Ding and Spelt 2007, 2008). Here, a pinned contact line of the drop is assumed. The evaporative mass flux at the liquid-vapour interface is a function of local temperature constitutively and treated as a source term in the interface evolution equation, i.e. Cahn-Hilliard equation. The model is validated by comparing its predictions with data available in the literature. The evaporative dynamics are illustrated in terms of drop snapshots, and a quantitative comparison with the results using a free surface model are made.

  13. CPAS Preflight Drop Test Analysis Process

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

    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.

  14. Effect of ambient temperature and relative humidity on interfacial temperature during early stages of drop evaporation

    NASA Astrophysics Data System (ADS)

    Fukatani, Yuki; Orejon, Daniel; Kita, Yutaku; Takata, Yasuyuki; Kim, Jungho; Sefiane, Khellil

    2016-04-01

    Understanding drop evaporation mechanisms is important for many industrial, biological, and other applications. Drops of organic solvents undergoing evaporation have been found to display distinct thermal patterns, which in turn depend on the physical properties of the liquid, the substrate, and ambient conditions. These patterns have been reported previously to be bulk patterns from the solid-liquid to the liquid-gas drop interface. In the present work the effect of ambient temperature and humidity during the first stage of evaporation, i.e., pinned contact line, is studied paying special attention to the thermal information retrieved at the liquid-gas interface through IR thermography. This is coupled with drop profile monitoring to experimentally investigate the effect of ambient temperature and relative humidity on the drop interfacial thermal patterns and the evaporation rate. Results indicate that self-generated thermal patterns are enhanced by an increase in ambient temperature and/or a decrease in humidity. The more active thermal patterns observed at high ambient temperatures are explained in light of a greater temperature difference generated between the apex and the edge of the drop due to greater evaporative cooling. On the other hand, the presence of water humidity in the atmosphere is found to decrease the temperature difference along the drop interface due to the heat of adsorption, absorption and/or that of condensation of water onto the ethanol drops. The control, i.e., enhancement or suppression, of these thermal patterns at the drop interface by means of ambient temperature and relative humidity is quantified and reported.

  15. Effect of ambient temperature and relative humidity on interfacial temperature during early stages of drop evaporation.

    PubMed

    Fukatani, Yuki; Orejon, Daniel; Kita, Yutaku; Takata, Yasuyuki; Kim, Jungho; Sefiane, Khellil

    2016-04-01

    Understanding drop evaporation mechanisms is important for many industrial, biological, and other applications. Drops of organic solvents undergoing evaporation have been found to display distinct thermal patterns, which in turn depend on the physical properties of the liquid, the substrate, and ambient conditions. These patterns have been reported previously to be bulk patterns from the solid-liquid to the liquid-gas drop interface. In the present work the effect of ambient temperature and humidity during the first stage of evaporation, i.e., pinned contact line, is studied paying special attention to the thermal information retrieved at the liquid-gas interface through IR thermography. This is coupled with drop profile monitoring to experimentally investigate the effect of ambient temperature and relative humidity on the drop interfacial thermal patterns and the evaporation rate. Results indicate that self-generated thermal patterns are enhanced by an increase in ambient temperature and/or a decrease in humidity. The more active thermal patterns observed at high ambient temperatures are explained in light of a greater temperature difference generated between the apex and the edge of the drop due to greater evaporative cooling. On the other hand, the presence of water humidity in the atmosphere is found to decrease the temperature difference along the drop interface due to the heat of adsorption, absorption and/or that of condensation of water onto the ethanol drops. The control, i.e., enhancement or suppression, of these thermal patterns at the drop interface by means of ambient temperature and relative humidity is quantified and reported. PMID:27176386

  16. A model of the evaporation of binary-fuel clusters of drops

    NASA Technical Reports Server (NTRS)

    Harstad, K.; Bellan, J.

    1991-01-01

    A formulation has been developed to describe the evaporation of dense or dilute clusters of binary-fuel drops. The binary fuel is assumed to be made of a solute and a solvent whose volatility is much lower than that of the solute. Convective flow effects, inducing a circulatory motion inside the drops, are taken into account, as well as turbulence external to the cluster volume. Results obtained with this model show that, similar to the conclusions for single isolated drops, the evaporation of the volatile is controlled by liquid mass diffusion when the cluster is dilute. In contrast, when the cluster is dense, the evaporation of the volatile is controlled by surface layer stripping, that is, by the regression rate of the drop, which is in fact controlled by the evaporation rate of the solvent. These conclusions are in agreement with existing experimental observations. Parametric studies show that these conclusions remain valid with changes in ambient temperature, initial slip velocity between drops and gas, initial drop size, initial cluster size, initial liquid mass fraction of the solute, and various combinations of solvent and solute. The implications of these results for computationally intensive combustor calculations are discussed.

  17. Evaporation of sessile drops containing colloidal rods: coffee-ring and order-disorder transition.

    PubMed

    Dugyala, Venkateshwar Rao; Basavaraj, Madivala G

    2015-03-01

    Liquid drops containing insoluble solutes when dried on solid substrates leave distinct ring-like deposits at the periphery or along the three-phase contact line-a phenomena popularly known as the coffee-ring or the coffee stain effect. The formation of such rings as well as their suppression is shown to have applications in particle separation and disease diagnostics. We present an experimental study of the evaporation of sessile drops containing silica rods to elucidate the structural arrangement of particles in the ring, an effect of the addition of surfactant and salt. To this end, the evaporation of aqueous sessile drops containing model rod-like silica particles of aspect ratio ranging from ∼4 to 15 on a glass slide is studied. We first show that when the conditions such as (1) solvent evaporation, (2) nonzero contact angle, (3) contact line pinning, (4) no surface tension gradient driven flow, and (5) repulsive particle-particle/particle-substrate interactions, that are necessary for the formation of the coffee-ring are met, the suspension drops containing silica rods upon evaporation leave a ring-like deposit. A closer examination of the ring deposits reveals that several layers of silica rods close to the edge of the drop are ordered such that the major axis of the rods are oriented parallel to the contact line. After the first few layers of ordered arrangement of particles, a random arrangement of particles in the drop interior is observed indicating an order-disorder transition in the ring. We monitor the evolution of the ring width and particle velocity during evaporation to elucidate the mechanism of the order-disorder transition. Moreover, when the evaporation rate is lowered, the ordering of silica rods is observed to extend over large areas. We demonstrate that the nature of the deposit can be tuned by the addition of a small quantity of surfactant or salt. PMID:25521279

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

    NASA Technical Reports Server (NTRS)

    Zhang, Neng-Li; Chao, David F.

    2001-01-01

    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.

  19. Evaporation duct communication: Test Plan

    NASA Astrophysics Data System (ADS)

    Anderson, K. D.

    1991-02-01

    The Evaporation Duct Communication (EDCOM) project is an effort to provide an alternative ship-to-ship communications channel using the natural environment. A microwave communication link can be used on an over-the-water, over-the-horizon path through the evaporation duct. This report shows how a microwave communication link, operating at a range separation of more than twice the line-of-sight range, can be constructed. This link can achieve about 80-percent availability at a transmission frequency of 14.5 GHz and can be constructed using off-the-shelf RF equipment. Operation of this link will provide the first set of measurements of channel capacity that can be critically dependent on the existence of an oceanic evaporation duct. Construction of this link presents a unique opportunity to study and evaluate an alternative communications channel that can be used to alleviate naval battlegroup communications load.

  20. 49 CFR 178.603 - Drop test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... qualification of all packaging design types and performed periodically as specified in § 178.601(e). For other than flat drops, the center of gravity of the test packaging must be vertically over the point of... result in failure of the packaging must be used. The number of drops required and the...

  1. Colloidal Drop Deposition on Porous Substrates: Competition among Particle Motion, Evaporation, and Infiltration.

    PubMed

    Pack, Min; Hu, Han; Kim, Dong-Ook; Yang, Xin; Sun, Ying

    2015-07-28

    Recent interest in printable electronics and in particular paper- and textile-based electronics has fueled research in inkjet printing of colloidal drops on porous substrates. On nonporous substrates, the interplay of particle motion and solvent evaporation determines the final deposition morphology of the evaporating colloidal drop. For porous substrates, solvent infiltration into the pores adds a layer of complexity to the deposition patterns that have not been fully elucidated in the literature. In this study, the deposition of picoliter-sized aqueous colloidal droplets containing nanometer- and micrometer-sized particles onto nanoporous anodic aluminum oxide substrates is examined for different drop and particle sizes and relative humidities as well as pore diameters, porosities, and wettabilities of the porous substrates. For the cases considered, solvent infiltration is found to be much faster than both evaporation and particle motion near the contact line, and thus when the substrate fully imbibes the solvent, the well-known "coffee-ring" deposition is suppressed. However, when the solvent is only partially imbibed, a residual droplet volume exists upon completion of the infiltration. For such cases, two time scales are of importance: the time for particle motion to the contact line as a result of both diffusion and advection, t(P), and the evaporation time of the residual drop volume, t(EI). Their ratio, t(P)/t(EI), determines whether the coffee-ring deposition will be formed (t(P)/t(EI) < 1) or suppressed (t(P)/t(EI) > 1). PMID:26132211

  2. Effects of Particle Shape on Growth Dynamics at Edges of Evaporating Drops of Colloidal Suspensions

    NASA Astrophysics Data System (ADS)

    Yunker, Peter J.; Lohr, Matthew A.; Still, Tim; Borodin, Alexei; Durian, D. J.; Yodh, A. G.

    2013-03-01

    We study the influence of particle shape on growth processes at the edges of evaporating drops. Aqueous suspensions of colloidal particles evaporate on glass slides, and convective flows during evaporation carry particles from drop center to drop edge, where they accumulate. The resulting particle deposits grow inhomogeneously from the edge on the air-water interface in two-dimensions. The deposition front, or growth line, varies in space and time. Measurements of the fluctuations of the deposition front during evaporation enable us to identify distinct growth processes. Interestingly, three distinct growth processes were discovered in the evaporating colloidal suspensions by tuning particle shape-dependent capillary interactions and thus varying the microscopic rules of deposition. Sphere deposition exhibits a classic Poisson like growth process; deposition of slightly anisotropic particles, however, appears to belong to the Kardar-Parisi-Zhang (KPZ) universality class, and deposition of highly anisotropic ellipsoids appears to belong to a third universality class, characterized by KPZ fluctuations in the presence of quenched disorder. We gratefully acknowledge financial support from the National Science Foundation through DMR-0804881, the PENN MRSEC DMR11-20901, and NASA NNX08AO0G.

  3. Drop Testing Representative Multi-Canister Overpacks

    SciTech Connect

    Snow, Spencer D.; Morton, Dana K.

    2015-06-01

    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.

  4. Deposition from evaporating drops: Power laws and new morphologies in coffee stains

    NASA Astrophysics Data System (ADS)

    Freed-Brown, Julian E.

    We investigate the structure of stains formed through evaporative deposition in sessile drops. Commonly, the deposited stain has a high surface density near the three phase contact line of the drying drop and much less solute in the bulk of the drop. This is known as the ``coffee ring effect'' and primarily arises due to contact line pinning. While many features of the stain depend on subtle physical phenomena within the drop, the coffee ring effect stands out as a robust feature that persists in many varied experimental realizations. In 2009, Witten predicted another robust feature of deposited stains: an asymptotic regime where a robust power law governs the fadeout profile of the stain into the interior of the drop. This power law is only controlled by geometric properties at a single point and the power does not vary along the contact line. We investigate the approach to this power law using numerical methods. For many evaporation profiles (including common experimental ones) the numerics show good agreement with the power law prediction. However, we demonstrate an intuitive scheme to construct evaporation profiles that subvert the power law prediction. We find that, in general, the approach to the power law cannot be known without full knowledge of the evaporation and height profile. We also extend this work in another way. We apply the basic arguments of the coffee ring effect to the case where the drop has a receding contact line. Here, we develop a new theoretical framework for deposition that has not previously been studied. In this context, the surface density profile can be directly calculated. Unlike a pinned contact line, receding contact lines push fluid into the interior of the drop. This effect can be overcome by strong evaporation near the contact line, but in general the intuition from contact line pinning is reversed. Following Witten's example, we find that the surface density of the stain near the center of the drop goes as eta ∝ rnu, where

  5. Deposition of bi-dispersed particles in inkjet-printed evaporating colloidal drops

    NASA Astrophysics Data System (ADS)

    Sun, Ying; Joshi, Abhijit; Chhasatia, Viral

    2010-11-01

    In this study, the deposition behaviors of inkjet-printed evaporating colloidal drops consisting of bi-dispersed micro and nano-sized particles are investigated by fluorescence microscopy and SEM. The results on hydrophilic glass substrates show that, evaporatively-driven outward flow drives the nanoparticles to deposit close to the pinned contact line while an inner ring deposition is formed by microparticles. This size-induced particle separation is consistent with the existence of a wedge-shaped drop edge near the contact line region of an evaporating drop on a hydrophilic substrate. The replenishing evaporatively-driven flow assembles nanoparticles closer to the pinned contact line forming an outer ring of nanoparticles and this particle jamming further enhances the contact line pinning. Microparticles are observed to form an inner ring inside the nano-sized deposits. This size-induced particle separation presents a new challenge to the uniformity of functional materials in bioprinting applications where nanoparticles and micro-sized cells are mixed together. On the other hand, particle self-assembly based on their sizes provides enables easy and well-controlled pattern formation. The effects of particle size contrast, particle volume fraction, substrate surface energy, and relative humidity of the printing environment on particle separation are examined in detail.

  6. 49 CFR 178.603 - Drop test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... specific gravity of 0.95 for testing at −18 °C (0 °F) or lower are considered acceptable test liquids. Test... specific gravity not exceeding 1.2, drop height must be determined according to packing group, as follows...: 0.8 m (2.6 feet). (ii) Where the materials to be transported have a specific gravity exceeding...

  7. Surfactant-induced Marangoni eddies alter the coffee-rings of evaporating colloidal drops.

    PubMed

    Still, Tim; Yunker, Peter J; Yodh, Arjun G

    2012-03-20

    The influence of the small ionic surfactant sodium dodecyl sulfate (SDS) on the evaporation of drying colloidal droplets is quantitatively investigated. The addition of SDS leads to a significantly more uniform deposition of colloidal particles after evaporation (i.e., the so-called "coffee-ring effect" is dramatically altered). We understand this phenomenon in the context of circulating radial Marangoni flows induced by the variation of SDS concentration along the air-water interface. Video microscopy permits the direct visualization of the colloidal particles involved in these flows, revealing a surprisingly stable "Marangoni eddy" that prevents particle deposition at the drop perimeter. PMID:22369657

  8. Smoothed particle hydrodynamics simulations of evaporation and explosive boiling of liquid drops in microgravity.

    PubMed

    Sigalotti, Leonardo Di G; Troconis, Jorge; Sira, Eloy; Peña-Polo, Franklin; Klapp, Jaime

    2015-07-01

    The rapid evaporation and explosive boiling of a van der Waals (vdW) liquid drop in microgravity is simulated numerically in two-space dimensions using the method of smoothed particle hydrodynamics. The numerical approach is fully adaptive and incorporates the effects of surface tension, latent heat, mass transfer across the interface, and liquid-vapor interface dynamics. Thermocapillary forces are modeled by coupling the hydrodynamics to a diffuse-interface description of the liquid-vapor interface. The models start from a nonequilibrium square-shaped liquid of varying density and temperature. For a fixed density, the drop temperature is increased gradually to predict the point separating normal boiling at subcritical heating from explosive boiling at the superheat limit for this vdW fluid. At subcritical heating, spontaneous evaporation produces stable drops floating in a vapor atmosphere, while at near-critical heating, a bubble is nucleated inside the drop, which then collapses upon itself, leaving a smaller equilibrated drop embedded in its own vapor. At the superheat limit, unstable bubble growth leads to either fragmentation or violent disruption of the liquid layer into small secondary drops, depending on the liquid density. At higher superheats, explosive boiling occurs for all densities. The experimentally observed wrinkling of the bubble surface driven by rapid evaporation followed by a Rayleigh-Taylor instability of the thin liquid layer and the linear growth of the bubble radius with time are reproduced by the simulations. The predicted superheat limit (T(s)≈0.96) is close to the theoretically derived value of T(s)=1 at zero ambient pressure for this vdW fluid. PMID:26274283

  9. Smoothed particle hydrodynamics simulations of evaporation and explosive boiling of liquid drops in microgravity

    NASA Astrophysics Data System (ADS)

    Sigalotti, Leonardo Di G.; Troconis, Jorge; Sira, Eloy; Peña-Polo, Franklin; Klapp, Jaime

    2015-07-01

    The rapid evaporation and explosive boiling of a van der Waals (vdW) liquid drop in microgravity is simulated numerically in two-space dimensions using the method of smoothed particle hydrodynamics. The numerical approach is fully adaptive and incorporates the effects of surface tension, latent heat, mass transfer across the interface, and liquid-vapor interface dynamics. Thermocapillary forces are modeled by coupling the hydrodynamics to a diffuse-interface description of the liquid-vapor interface. The models start from a nonequilibrium square-shaped liquid of varying density and temperature. For a fixed density, the drop temperature is increased gradually to predict the point separating normal boiling at subcritical heating from explosive boiling at the superheat limit for this vdW fluid. At subcritical heating, spontaneous evaporation produces stable drops floating in a vapor atmosphere, while at near-critical heating, a bubble is nucleated inside the drop, which then collapses upon itself, leaving a smaller equilibrated drop embedded in its own vapor. At the superheat limit, unstable bubble growth leads to either fragmentation or violent disruption of the liquid layer into small secondary drops, depending on the liquid density. At higher superheats, explosive boiling occurs for all densities. The experimentally observed wrinkling of the bubble surface driven by rapid evaporation followed by a Rayleigh-Taylor instability of the thin liquid layer and the linear growth of the bubble radius with time are reproduced by the simulations. The predicted superheat limit (Ts≈0.96 ) is close to the theoretically derived value of Ts=1 at zero ambient pressure for this vdW fluid.

  10. A comprehensive analysis of the evaporation of a liquid spherical drop.

    PubMed

    Sobac, B; Talbot, P; Haut, B; Rednikov, A; Colinet, P

    2015-01-15

    In this paper, a new comprehensive analysis of a suspended drop of a pure liquid evaporating into air is presented. Based on mass and energy conservation equations, a quasi-steady model is developed including diffusive and convective transports, and considering the non-isothermia of the gas phase. The main original feature of this simple analytical model lies in the consideration of the local dependence of the physico-chemical properties of the gas on the gas temperature, which has a significant influence on the evaporation process at high temperatures. The influence of the atmospheric conditions on the interfacial evaporation flux, molar fraction and temperature is investigated. Simplified versions of the model are developed to highlight the key mechanisms governing the evaporation process. For the conditions considered in this work, the convective transport appears to be opposed to the evaporation process leading to a decrease of the evaporation flux. However, this effect is relatively limited, the Péclet numbers happening to be small. In addition, the gas isothermia assumption never appears to be valid here, even at room temperature, due to the large temperature gradient that develops in the gas phase. These two conclusions are explained by the fact that heat transfer from the gas to the liquid appears to be the step limiting the evaporation process. Regardless of the complexity of the developed model, yet excluding extremely small droplets, the square of the drop radius decreases linearly over time (R(2) law). The assumptions of the model are rigorously discussed and general criteria are established, independently of the liquid-gas couple considered. PMID:25454455

  11. Orion Parachute Drop Test, July 18

    NASA Video Gallery

    A C-17 plane dropped a test version of Orion from an altitude of 25,000 feet above the U.S. Army Yuma Proving Ground in southwestern Arizona on July 18, 2012. This test was the second to use an Ori...

  12. 49 CFR 178.1045 - Drop test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR PACKAGINGS Testing of Flexible Bulk... Flexible Bulk Container design types and performed periodically as specified in § 178.1035(e) of this subpart. (b) Special preparation for the drop test. Flexible Bulk Containers must be filled to...

  13. Molecular dynamics simulations of the evaporation of particle-laden drops

    NASA Astrophysics Data System (ADS)

    Chen, Weikang; Koplik, Joel; Kretzschmar, Ilona

    2012-11-01

    We use molecular dynamics simulations to study the evaporation of particle-laden droplets on a heated surface. The droplets are composed of a Lennard-Jones fluid containing rigid particles which are spherical sections of an atomic lattice, and heating is controlled through the temperature of an atomistic substrate. We observe that sufficiently large (but still nano-sized) particle-laden drops exhibit contact line pinning, measure the outward fluid flow field which advects particle to the drop rim, and find that the structure of the resulting aggregate varies with inter-particle interactions. In addition, the profile of the evaporative fluid flux is measured with and without particles present, and is also found to be in qualitative agreement with earlier theory. The compatibility of simple nanoscale calculations and micron-scale experiments indicates that molecular simulation may be used to predict aggregate structure in vaporative growth processes.

  14. On thin evaporating drops: when is the d2-law valid?

    NASA Astrophysics Data System (ADS)

    Saxton, Matthew; Whiteley, Jonathan; Vella, Dominic; Oliver, James

    2015-11-01

    We study the evolution of a thin, axisymmetric, partially wetting drop as it evaporates. The stress singularity at the contact line is regularized using slip and we perform a matched-asymptotic analysis in the limit of small slip. A generalization of Tanner's law to account for the effect of mass transfer is derived and the behaviour of the drop close to extinction is analysed. We find a criterion for when the contact-set radius close to extinction evolves as the square-root of the time remaining until extinction--the famous d2-law. However, for a sufficiently large rate of evaporation, our analysis predicts that a `d 13 / 7-law' should be more appropriate. Our asymptotic results are validated by comparison with numerical simulations.

  15. Reduction, partial evaporation, and spattering - Possible chemical and physical processes in fluid drop chondrule formation

    NASA Technical Reports Server (NTRS)

    King, E. A.

    1983-01-01

    The major chemical differences between fluid drop chondrules and their probable parent materials may have resulted from the loss of volatiles such as S, H2O, Fe, and volatile siderophile elements by partial evaporation during the chondrule-forming process. Vertical access solar furnace experiments in vacuum and hydrogen have demonstrated such chemical fractionation trends using standard rock samples. The formation of immiscible iron droplets and spherules by in situ reduction of iron from silicate melt and the subsequent evaporation of the iron have been observed directly. During the time that the main sample bead is molten, many small spatter spherules are thrown off the main bead, thereby producing many additional chondrule-like melt spherules that cool rapidly and generate a population of spherules with size frequency distribution characteristics that closely approximate some populations of fluid drop chondrules in chondrites. It is possible that spatter-produced fluid drop chondrules dominate the meteoritic fluid drop chondrule populations. Such meteoritic chondrule populations should be chemically related by various relative amounts of iron and other volatile loss by vapor fractionation.

  16. DWPF Recycle Evaporator Shielded Cells Testing

    SciTech Connect

    Fellinger, T. L.; Herman, D. T.; Stone, M.E

    2005-07-01

    Testing was performed to determine the feasibility and processing characteristics of evaporation of actual Defense Waste Processing Facility (DWPF) recycle material. Samples of the Off Gas Condensate Tank (OGCT) and Slurry Mix Evaporator Condensate Tank (SMECT) were transferred from DWPF to the Savannah River National Lab (SRNL) Shielded Cells and blended with De-Ionized (DI) water and a small amount of Slurry Mix Evaporator (SME) product. A total of 3000 mL of this feed was concentrated to approximately 90 mL during a semi-batch evaporation test of approximately 17 hours. One interruption occurred during the run when the feed tube developed a split and was replaced. Samples of the resulting condensate and concentrate were collected and analyzed. The resulting analysis of the condensate was compared to the Waste Acceptance Criteria (WAC) limits for the F/H Effluent Treatment Plant (ETP). Results from the test were compared to previous testing using simulants and OLI modeling. Conclusions from this work included the following: (1) The evaporation of DWPF recycle to achieve a 30X concentration factor was successfully demonstrated. The feed blend of OGCT and SMECT material was concentrated from 3000 mL to approximately 90 mL during testing, a concentration of approximately 33X. (2) Foaming was observed during the run. Dow Corning 2210 antifoam was added seven times throughout the run at 100 parts per million (ppm) per addition. The addition of this antifoam was very effective in reducing the foam level, but the impact diminished over time and additional antifoam was required every 2 to 3 hours during the run. (3) No scale or solids formed on the evaporator vessel, but splatter was observed in the headspace of the evaporator vessel. No scaling formed on the stainless steel thermocouple. (4) The majority of the analytes met the F/H ETP WAC. However, the detection limits for selected species (Sr-90, Pu-238, Pu-240, Am-243, and Cm-244) exceeded the ETP WAC limits. (5) I

  17. 49 CFR 178.965 - Drop test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .... Water/anti-freeze solutions with a minimum specific gravity of 0.95 for testing at −18 °C (0 °F) or... having essentially the same physical characteristics. (3) The specific gravity and viscosity of a...: (i) Where the substances to be carried have a specific gravity not exceeding 1.2, the drop...

  18. 49 CFR 178.810 - Drop test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... solutions with a minimum specific gravity of 0.95 for testing at −18 °C (0 °F) or lower are considered... material having essentially the same physical characteristics. (3) The specific gravity and viscosity of a...: (i) Where the substances to be carried have a specific gravity not exceeding 1.2, the drop...

  19. 49 CFR 178.810 - Drop test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... solutions with a minimum specific gravity of 0.95 for testing at −18 °C (0 °F) or lower are considered... material having essentially the same physical characteristics. (3) The specific gravity and viscosity of a...: (i) Where the substances to be carried have a specific gravity not exceeding 1.2, the drop...

  20. 49 CFR 178.603 - Drop test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... of anti-freeze. Water/anti-freeze solutions with a minimum specific gravity of 0.95 for testing at... is performed with water: (i) Where the materials to be carried have a specific gravity not exceeding...) Where the materials to be transported have a specific gravity exceeding 1.2, the drop height must...

  1. 49 CFR 178.965 - Drop test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    .... Water/anti-freeze solutions with a minimum specific gravity of 0.95 for testing at −18 °C (0 °F) or... having essentially the same physical characteristics. (3) The specific gravity and viscosity of a...: (i) Where the substances to be carried have a specific gravity not exceeding 1.2, the drop...

  2. 49 CFR 178.810 - Drop test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... solutions with a minimum specific gravity of 0.95 for testing at −18 °C (0 °F) or lower are considered... material having essentially the same physical characteristics. (3) The specific gravity and viscosity of a...: (i) Where the substances to be carried have a specific gravity not exceeding 1.2, the drop...

  3. 49 CFR 178.603 - Drop test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... of anti-freeze. Water/anti-freeze solutions with a minimum specific gravity of 0.95 for testing at... is performed with water: (i) Where the materials to be carried have a specific gravity not exceeding...) Where the materials to be transported have a specific gravity exceeding 1.2, the drop height must...

  4. 49 CFR 178.965 - Drop test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    .... Water/anti-freeze solutions with a minimum specific gravity of 0.95 for testing at −18 °C (0 °F) or... having essentially the same physical characteristics. (3) The specific gravity and viscosity of a...: (i) Where the substances to be carried have a specific gravity not exceeding 1.2, the drop...

  5. 49 CFR 178.810 - Drop test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... solutions with a minimum specific gravity of 0.95 for testing at −18 °C (0 °F) or lower are considered... material having essentially the same physical characteristics. (3) The specific gravity and viscosity of a...: (i) Where the substances to be carried have a specific gravity not exceeding 1.2, the drop...

  6. 49 CFR 178.965 - Drop test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    .... Water/anti-freeze solutions with a minimum specific gravity of 0.95 for testing at −18 °C (0 °F) or... having essentially the same physical characteristics. (3) The specific gravity and viscosity of a...: (i) Where the substances to be carried have a specific gravity not exceeding 1.2, the drop...

  7. Water Drop Evaporation on Mushroom-like Superhydrophobic Surfaces: Temperature Effects.

    PubMed

    do Nascimento, Rodney Marcelo; Cottin-Bizonne, Cécile; Pirat, Christophe; Ramos, Stella M M

    2016-03-01

    We report on experiments of drop evaporation on heated superhydrophobic surfaces decorated with micrometer-sized mushroom-like pillars. We analyze the influence of two parameters on the evaporation dynamics: the solid-liquid fraction and the substrate temperature, ranging between 30 and 80 °C. In the different configurations investigated, the drop evaporation appears to be controlled by the contact line dynamics (pinned or moving). The experimental results show that (i) in the pinned regime, the depinning angles increase with decreasing contact fraction and the substrate heating promotes the contact line depinning and (ii) in the moving regime, the droplet motion is described by periodic stick-slip events and contact-angle oscillations. These features are highly smoothed at the highest temperatures, with two possible mechanisms suggested to explain such a behavior, a reduction in the elasticity of the triple line and a decrease in the depinning energy barriers. For all surfaces, the observed remarkable stability of the "fakir" state to the temperature is attributed to the re-entrant micropillar curvature that prevents surface imbibition. PMID:26854562

  8. Assessment of evaporation equilibrium and stability concerning an acoustically excited drop in combustion products

    NASA Astrophysics Data System (ADS)

    Mauriot, Yves; Prud'homme, Roger

    2014-04-01

    The evaporation of drops in a sound field has been the subject of numerous studies aimed at determining its role in combustion instability. The models generally assume local equilibrium evaporation at the interface. We determine here the conditions of validity of this assumption, without calling into question other a priori assumptions of the classical model, in particular spherically symmetric quasi-steady evolution in the gas phase and liquid phase thermal unsteadiness with pure heat conduction. Another possible phenomenon concerns the differential recoil of the vapor. In the case of rapid evaporation, a pressure difference appears between both sides of the interface, even if the latter is plane. This pressure difference, usually neglected, is proportional to the square of speed and the resulting force is oriented toward the denser fluid, i.e. the liquid. A very fast evaporation may even cause local deformation, i.e. Hickman instability. The stability condition concerning this phenomenon has also been determined. This study was co-funded by CNES (French Space Agency) and ONERA and was performed in the framework of CNES-ONERA French Research &  Technology activities on the high-frequency combustion stability of liquid-propellant rocket engines.

  9. Discrete Element Modeling of Drop Tests

    NASA Astrophysics Data System (ADS)

    Wang, Yuannian; Tonon, Fulvio

    2012-09-01

    A discrete element code with impact model has been developed and calibrated to simulate the dynamic behavior of rock materials, with special regard to rock fragmentation upon impact during rock-fall analysis. The paper summarizes the discrete element code, the calibration algorithms developed to identify the model microparameters, and the impact model. Experimental work on drop tests is then used to validate the code on modeling impact fragmentation. It has been found that the developed discrete element code and impact model can reasonably simulate rock fragmentation in drop tests. The use of the discrete element code and impact model can provide good reference results in evaluating impact fragmentation in rock-fall analysis.

  10. 14 CFR 23.727 - Reserve energy absorption drop test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 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...

  11. 14 CFR 23.727 - Reserve energy absorption drop test.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 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...

  12. 14 CFR 23.727 - Reserve energy absorption drop test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 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...

  13. 14 CFR 23.727 - Reserve energy absorption drop test.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 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...

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

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 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...

  15. Evaporation dynamics of non-spherical sessile drops of pure fluids and binary mixtures

    NASA Astrophysics Data System (ADS)

    Saenz, Pedro J.; Matar, Omar K.; Sefiane, Khellil; Valluri, Prashant; Kim, Jungho

    2015-11-01

    The dynamics of pure axisymmetric volatile sessile droplets have been meticulously examined over the last four decades but remain poorly understood. Studies focusing on more realistic non-spherical configurations are virtually non-existent. The dynamics of the latter are examined in this investigation by means of experiments and numerical simulations. We show that the lifetime and bulk flow characteristics of these drops depend on their size and shape. The irregular geometries lead to the emergence preferential convection currents in the liquid as well as differential local evaporation rates noticeable along the contact line. Similarly, we inspect the thermocapillary stability of the flow, which results as the liquid volatility increases, and find that this is also affected by the non-uniform wettability along the triple line. The Marangoni-driven instabilities grow in an intricate spatio-temporal fashion leading to the emergence of different flow regimes. Finally, we also provide new insights into the evaporation process of binary-mixture drops. Memphis Multiphase (EPSRC EP/K003976/1) & ThermaPOWER (EU IRSES-PIRSES GA-2011-294905).

  16. Analytic study of developing flows in a tube laden with non-evaporating and evaporating drops via a modified linearization of the two-phase momentum equations

    NASA Astrophysics Data System (ADS)

    Khosid, S.; Tambour, Y.

    A novel modification of the classical Langhaar linearization of the mutually coupled momentum equations for developing two-phase flows in circular ducts is presented. This modification enables us to treat: (i) flows developing from spatially periodic initial velocity distributions without the presence of droplets, and (ii) two-phase flows in which monosize, non-evaporating and evaporating droplets suspended in a developing gas flow of an initially uniform velocity distribution exchange momentum with the host-gas flow. New solutions are presented for the downstream evolution in the velocity profiles which develop from spatially periodic initial velocity distributions that eventually reach the fully developed Poiseuille velocity profile. These solutions are validated by employing known numerical procedures, providing strong support for the physical underpinnings of the present modified linearization. New solutions are also presented for the evolution in drop velocities and vapour spatial distributions for evaporating droplets suspended in an initially uniform velocity profile of the host gas. Asymptotic solutions are presented for the flow region which lies very close to the inlet of the tube, where the relative velocity between the droplets and the host gas is high, and thus the velocity fields of the two phases are mutually coupled. These solutions provide new explicit formulae for the droplet velocity field as a function of the initial conditions and droplet diameter (relative to the tube diameter) for non-evaporating drops, and also as a function of evaporation rate for evaporating drops.

  17. 14 CFR 29.725 - Limit drop test.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit drop test. 29.725 Section 29.725 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Landing Gear § 29.725 Limit drop test. The limit drop test must be conducted...

  18. 14 CFR 27.725 - Limit drop test.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit drop test. 27.725 Section 27.725 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Landing Gear § 27.725 Limit drop test. The limit drop test must be conducted...

  19. 14 CFR 29.727 - Reserve energy absorption drop test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Reserve energy absorption drop test. 29.727 Section 29.727 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION....727 Reserve energy absorption drop test. The reserve energy absorption drop test must be conducted...

  20. 14 CFR 27.727 - Reserve energy absorption drop test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Reserve energy absorption drop test. 27.727 Section 27.727 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Reserve energy absorption drop test. The reserve energy absorption drop test must be conducted as...

  1. 14 CFR 27.727 - Reserve energy absorption drop test.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Reserve energy absorption drop test. 27.727 Section 27.727 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Reserve energy absorption drop test. The reserve energy absorption drop test must be conducted as...

  2. 14 CFR 29.727 - Reserve energy absorption drop test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Reserve energy absorption drop test. 29.727 Section 29.727 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION....727 Reserve energy absorption drop test. The reserve energy absorption drop test must be conducted...

  3. 14 CFR 29.727 - Reserve energy absorption drop test.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Reserve energy absorption drop test. 29.727 Section 29.727 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION....727 Reserve energy absorption drop test. The reserve energy absorption drop test must be conducted...

  4. 14 CFR 27.727 - Reserve energy absorption drop test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Reserve energy absorption drop test. 27.727 Section 27.727 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Reserve energy absorption drop test. The reserve energy absorption drop test must be conducted as...

  5. 14 CFR 27.727 - Reserve energy absorption drop test.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Reserve energy absorption drop test. 27.727 Section 27.727 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Reserve energy absorption drop test. The reserve energy absorption drop test must be conducted as...

  6. 14 CFR 29.727 - Reserve energy absorption drop test.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Reserve energy absorption drop test. 29.727 Section 29.727 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION....727 Reserve energy absorption drop test. The reserve energy absorption drop test must be conducted...

  7. 14 CFR 27.727 - Reserve energy absorption drop test.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Reserve energy absorption drop test. 27.727 Section 27.727 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Reserve energy absorption drop test. The reserve energy absorption drop test must be conducted as...

  8. 14 CFR 29.727 - Reserve energy absorption drop test.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Reserve energy absorption drop test. 29.727 Section 29.727 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION....727 Reserve energy absorption drop test. The reserve energy absorption drop test must be conducted...

  9. A New Approach to Measure Contact Angle and Evaporation Rate with Flow Visualization in a Sessile Drop

    NASA Technical Reports Server (NTRS)

    Zhang, Nengli; Chao, David F.

    1999-01-01

    The contact angle and the spreading process of sessile droplet are very crucial in many technological processes, such as painting and coating, material processing, film-cooling applications, lubrication, and boiling. Additionally, as it is well known that the surface free energy of polymers cannot be directly, measured for their elastic and viscous restraints. The measurements of liquid contact angle on the polymer surfaces become extremely important to evaluate the surface free energy of polymers through indirect methods linked with the contact angle data. Due to the occurrence of liquid evaporation is inevitable, the effects of evaporation on the contact angle and the spreading become very important for more complete understanding of these processes. It is of interest to note that evaporation can induce Marangoni-Benard convection in sessile drops. However, the impacts of the inside convection on the wetting and spreading processes are not clear. The experimental methods used by previous investigators cannot simultaneously measure the spreading process and visualize the convection inside. Based on the laser shadowgraphic system used by the present author, a very simple optical procedure has been developed to measure the contact angle, the spreading speed, the evaporation rate, and to visualize inside convection of a sessile drop simultaneously. Two CCD cameras were used to synchronously record the real-time diameter of the sessile drop, which is essential for determination of both spreading speed and evaporation rate, and the shadowgraphic image magnified by the sessile drop acting as a thin plano-convex lens. From the shadowgraph, the inside convection of the drop can be observed if any and the image outer diameter, which linked to the drop profile, can be measured. Simple equations have been derived to calculate the drop profile, including the instantaneous contact angle, height, and volume of the sessile drop, as well as the evaporation rate. The influence of

  10. Evaporation of a water drop with a solid opaque inclusion moving through a high-temperature gaseous medium

    NASA Astrophysics Data System (ADS)

    Antonov, D. V.; Volkov, R. S.; Piskunov, M. V.; Strizhak, P. A.

    2016-03-01

    The process of evaporation of an inhomogeneous (containing a graphite particle) water drop moving through a high-temperature (about 1100 K) gas medium has been experimentally studied using highspeed (no less than 105 fps) video recording tools, the PIV scanning optical method, and Tema Automotive software. The influences of the ratio of water and inclusion masses, shape of inclusion (by the example of cylindrical disk, cube, and parallelepiped), and its surface area on the integral characteristics of liquid evaporation when heterogeneous drops are passed through a channel (length 1 m, inner diameter 0.2 m) with high-temperature gases are established.

  11. Predicting Equations for Evaporation Pressure Drop Inside Horizontal Smooth and Grooved Tubes

    NASA Astrophysics Data System (ADS)

    Kubota, Atsushi; Uchida, Mari; Shikazono, Naoki

    A new prediction method for evaporation pressure drop inside horizontal smooth and grooved tubes is proposed. These tubes had an outer diameter of 7mm, and the working fluids were R407C (HFC-32/HFC-125/HFC-134a, 23/25/52 mass%) and R410A (HFC-32/HFC-125, 50/50 mass%). The previous and present experimental data were correlated by Lockhart-Martinelli method, where Colburn and Carnavos equations were utilized for predicting single phase pressure drop of smooth and grooved tubes, respectively. Different numerical constants were adopted for smooth and grooved tubes to calculate the L-M pressure parameter φ L.Inorder to express the gravitational effect, a damping function for φ L was introduced. The proposed damping function was expressed as a function of Froude number for both smooth and grooved tubes. It is confirmed that 95% of the predicted results are within the accuracy of ±30% for both smooth and grooved tubes.

  12. Heat and Mass Exchange of a Drop of a Solution Subjected to a Combined Energy Action Under Conditions of Deepening of the Evaporation Zone

    NASA Astrophysics Data System (ADS)

    Akulich, P. V.

    2016-05-01

    A model of the heat and mass exchange in the evaporation of drops moving in the carrying gas phase of a solution subjected to the combined energy action of a convective heat flow and electromagnetic infrared and microwave radiations under conditions where the size of the drops changes at the low-temperature stage of their evaporation and the evaporation zone deepens at the high-temperature stage of the evaporation process has been formulated. Kinetic dependences and features of the movement of the evaporation boundary in the process of dehydration of the indicated drops have been determined.

  13. Heat and Mass Exchange of a Drop of a Solution Subjected to a Combined Energy Action Under Conditions of Deepening of the Evaporation Zone

    NASA Astrophysics Data System (ADS)

    Akulich, P. V.

    2016-06-01

    A model of the heat and mass exchange in the evaporation of drops moving in the carrying gas phase of a solution subjected to the combined energy action of a convective heat flow and electromagnetic infrared and microwave radiations under conditions where the size of the drops changes at the low-temperature stage of their evaporation and the evaporation zone deepens at the high-temperature stage of the evaporation process has been formulated. Kinetic dependences and features of the movement of the evaporation boundary in the process of dehydration of the indicated drops have been determined.

  14. Ares I Upper Stage Parachute Drop Test

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Under the goals of the Vision for Space Exploration, Ares I is a chief component of the cost-effective space transportation infrastructure being developed by NASA's Constellation Program. This transportation system will safely and reliably carry human explorers back to the moon, and then onward to Mars and other destinations in the solar system. The Ares I effort includes multiple project element teams at NASA centers and contract organizations around the nation, and is managed by the Exploration Launch Projects Office at NASA's Marshall Space Flight Center (MFSC). ATK Launch Systems near Brigham City, Utah, is the prime contractor for the first stage booster. ATK's subcontractor, United Space Alliance of Houston, is designing, developing and testing the parachutes at its facilities at NASA's Kennedy Space Center in Florida. NASA's Johnson Space Center in Houston hosts the Constellation Program and Orion Crew Capsule Project Office and provides test instrumentation and support personnel. Together, these teams are developing vehicle hardware, evolving proven technologies, and testing components and systems. Their work builds on powerful, reliable space shuttle propulsion elements and nearly a half-century of NASA space flight experience and technological advances. Ares I is an inline, two-stage rocket configuration topped by the Crew Exploration Vehicle, its service module, and a launch abort system. In this HD video image, the first stage reentry parachute drop test is conducted at the Yuma, Arizona proving ground. The parachute tests demonstrated a three-stage deployment sequence that included the use of an Orbiter drag chute to properly stage the unfurling of the main chute. The parachute recovery system for Orion will be similar to the system used for Apollo command module landings and include two drogue, three pilot, and three main parachutes. (Highest resolution available)

  15. Ares I Upper Stage Parachute Drop Test

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Under the goals of the Vision for Space Exploration, Ares I is a chief component of the cost-effective space transportation infrastructure being developed by NASA's Constellation Program. This transportation system will safely and reliably carry human explorers back to the moon, and then onward to Mars and other destinations in the solar system. The Ares I effort includes multiple project element teams at NASA centers and contract organizations around the nation, and is managed by the Exploration Launch Projects Office at NASA's Marshall Space Flight Center (MFSC). ATK Launch Systems near Brigham City, Utah, is the prime contractor for the first stage booster. ATK's subcontractor, United Space Alliance of Houston, is designing, developing and testing the parachutes at its facilities at NASA's Kennedy Space Center in Florida. NASA's Johnson Space Center in Houston hosts the Constellation Program and Orion Crew Capsule Project Office and provides test instrumentation and support personnel. Together, these teams are developing vehicle hardware, evolving proven technologies, and testing components and systems. Their work builds on powerful, reliable space shuttle propulsion elements and nearly a half-century of NASA space flight experience and technological advances. Ares I is an inline, two-stage rocket configuration topped by the Crew Exploration Vehicle, its service module, and a launch abort system. In this HD video image, the first stage reentry parachute drop test is conducted at the Yuma, Arizona proving ground. The parachute tests demonstrated a three-stage deployment sequence that included the use of an Orbiter drag chute to properly stage the unfurling of the main chute. The parachute recovery system for Orion will be similar to the system used for Apollo command module landings and include two drogue, three pilot, and three main parachutes. (Highest resolution available)

  16. Flexible and precise drop test system

    NASA Astrophysics Data System (ADS)

    Stämpfli, Rolf; Brühwiler, Paul A.

    2009-11-01

    A drop test system with flexibility in the choice of falling object has been constructed and characterized. Using the guided free fall principle, the system enables the study of impacts of a large range of objects on a wide selection of anvils, with high control of the position and orientation of the object. The latter is demonstrated with falls of a standard aluminium headform in mountaineering helmets on a kerbstone anvil, for which visual inspection with a high-speed camera confirms the desired accuracy. Impacts of a flat falling body on cylindrical polystyrene foam samples are used to derive stress-strain curves for materials of different density and for multilayer samples. In this case, the effects of striker orientation and placement on the resultant data are discussed, and the reproducibility of the data serves as an additional confirmation of the accuracy of the measurement apparatus and procedures. A check on the improvement in the level of positional and orientational striking precision achievable is obtained via an inter-laboratory comparison.

  17. Hollow Fiber Ground Evaporator Unit Testing

    NASA Technical Reports Server (NTRS)

    Bue, Grant; Trevino, Luis; Tsioulos, Gus

    2010-01-01

    A candidate technology for 1-atmosphere suited heat rejection was developed and tested at NASA Johnson Space Center. The concept is to use a collection of microporous hydrophobic tubes potted between inlet and outlet headers with water as coolant. A pump provides flow between headers through the tubes which are subjected to fan driven cross flow of relatively dry air. The forced ventilation would sweep out the water vapor from the evaporation of the coolant rejecting heat from the coolant stream. The hollow fibers are obtained commercially (X50-215 Celgard) which are arranged in a sheet containing 5 fibers per linear inch. Two engineering development units were produced that vary the fold direction of the fiber sheets relative to the ventilation. These units were tested at inlet water temperatures ranging from 20 deg C to 30 deg C, coolant flow rates ranging from 10 to 90 kg/hr, and at three fan speeds. These results were used to size a system that could reject heat at a rate of 340 W.

  18. Evaporation duct communication: Test plan, part 2

    NASA Astrophysics Data System (ADS)

    Anderson, K. D.; Rogers, L. T.

    1991-11-01

    This document is a continuation and expansion of an earlier study that examines the feasibility of using the evaporation duct to support an alternative high-speed communication system for Navy applications. This Evaporation Duct Communication (EDCOM) experiment is a unique opportunity to evaluate another communication channel that can alleviate Navy ship-to-ship communication problems. Therefore, it is strongly recommended to proceed with this measurement program.

  19. Calcium carbonate mineralization: X-ray microdiffraction probing of the interface of an evaporating drop on a superhydrophobic surface.

    PubMed

    Accardo, Angelo; Burghammer, Manfred; Di Cola, Emanuela; Reynolds, Michael; Di Fabrizio, Enzo; Riekel, Christian

    2011-07-01

    The liquid/air interface of calcium bicarbonate solution drops was probed by synchrotron radiation microbeam scattering. The drops were deposited on a nanopatterned superhydrophobic poly(methyl methacrylate) surface and raster-scanned during evaporation by small-angle and wide-angle X-ray scattering. The appearance of about 200-nm-size calcite crystallites at the interface could be spatially resolved at the onset of crystallization. Diffuse scattering from the interface is attributed to a dense nanoscale amorphous calcium carbonate phase. Calcite was found to be the major phase in the solid residue with vaterite as minor phase. PMID:21663321

  20. Drop Tests of the Closure Ring for the 9975 Package

    SciTech Connect

    Smith, A.C

    1999-09-29

    The drop tests of the closure ring for 9975 packages, described here, were performed to answer questions raised by the regulatory authority as a result of deformation of the closure ring and drum rim observed during drop tests conducted in September 1998.

  1. 14 CFR 23.725 - Limit drop tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Landing Gear... than 18.7 inches. (b) If the effect of wing lift is provided for in free drop tests, the landing gear... be determined in a rational or conservative manner, during the drop test, using a landing gear...

  2. Consistent Large-Eddy Simulation of a Temporal Mixing Layer Laden with Evaporating Drops. Part 2; A Posteriori Modelling

    NASA Technical Reports Server (NTRS)

    Leboissertier, Anthony; Okong'O, Nora; Bellan, Josette

    2005-01-01

    Large-eddy simulation (LES) is conducted of a three-dimensional temporal mixing layer whose lower stream is initially laden with liquid drops which may evaporate during the simulation. The gas-phase equations are written in an Eulerian frame for two perfect gas species (carrier gas and vapour emanating from the drops), while the liquid-phase equations are written in a Lagrangian frame. The effect of drop evaporation on the gas phase is considered through mass, species, momentum and energy source terms. The drop evolution is modelled using physical drops, or using computational drops to represent the physical drops. Simulations are performed using various LES models previously assessed on a database obtained from direct numerical simulations (DNS). These LES models are for: (i) the subgrid-scale (SGS) fluxes and (ii) the filtered source terms (FSTs) based on computational drops. The LES, which are compared to filtered-and-coarsened (FC) DNS results at the coarser LES grid, are conducted with 64 times fewer grid points than the DNS, and up to 64 times fewer computational than physical drops. It is found that both constant-coefficient and dynamic Smagorinsky SGS-flux models, though numerically stable, are overly dissipative and damp generated small-resolved-scale (SRS) turbulent structures. Although the global growth and mixing predictions of LES using Smagorinsky models are in good agreement with the FC-DNS, the spatial distributions of the drops differ significantly. In contrast, the constant-coefficient scale-similarity model and the dynamic gradient model perform well in predicting most flow features, with the latter model having the advantage of not requiring a priori calibration of the model coefficient. The ability of the dynamic models to determine the model coefficient during LES is found to be essential since the constant-coefficient gradient model, although more accurate than the Smagorinsky model, is not consistently numerically stable despite using DNS

  3. Drop tests of the Three Mile Island knockout canister

    SciTech Connect

    Box, W D; Aaron, W S; Shappert, L B; Childress, P C; Quinn, G J; Smith, J V

    1987-01-01

    A type of Three Mile Island Unit 2 (TMI-2) defueling canister, called a ''knockout'' canister, was subjected to a series of drop tests at the Oak Ridge National Laboratory's Drop Test Facility. These tests confirmed the structural integrity of internal fixed neutron poisons in support of a request for NRC licensing of this type of canister for the shipment of TMI-2 reactor fuel debris to the Idaho National Engineering Laboratory (INEL) for the Core Examination R and D Program. This report presents the data generated and the results obtained from a series of four drop tests that included two drops with the test assembly in the vertical position and two drops with the assembly in the horizontal position.

  4. Suppressing the coffee stain effect: how to control colloidal self-assembly in evaporating drops using electrowetting

    NASA Astrophysics Data System (ADS)

    Eral, Burak; Mampallil Augustine, Dileep; Duits, Michel; Mugele, Frieder; Physics of Complex Fluids Group, University of Twente Team

    2011-11-01

    We study the influence of electrowetting on the evaporative self-assembly and formation of undesired solute residues, so-called coffee stains, during the evaporation of a drop containing non-volatile solvents. Electrowetting is found to suppress coffee stains of both colloidal particles of various sizes and DNA solutions at alternating (AC) frequencies ranging from a few Hertz to a few tens of kHz. Two main effects are shown to contribute to the suppression: (i) the time-dependent electrostatic force prevents pinning of the three phase contact line and (ii) internal flow fields generated by AC electrowetting counteract the evaporation driven flux and thereby prevent the accumulation of solutes along the contact line Please see the link below for a short presentation and movies: http://www.youtube.com/watch?v=xwipCVZnN4E We thank the Chemical Sciences division of the Netherlands Organization for Scientific Research (NWO-CW) for financial support (ECHO grant).

  5. Orion Drop Test - Dec. 13, 2011

    NASA Video Gallery

    Testing continues at NASA Langley Research Center as the 18,000-pound (8,165 kg) Orion test article took its eight and final splash of the year into the Hydro Impact Basin on Dec. 13. This test sim...

  6. Orion MPCV Phase 1 Drop Test

    NASA Video Gallery

    Engineers conducted the first test as part of Phase 1 of the Orion MPCV boilerplate test article at NASA's Langley Research Center, on Oct. 18. The 18,000-pound (8,165 kg) test article -- represent...

  7. Drop tests of the Three Mile Island knockout canister

    SciTech Connect

    Box, W.D.; Aaron, W.S.; Shappert, L.B.; Childress, P.C.; Quinn, G.J.; Smith, J.V.

    1986-09-01

    A type of Three Mile Island Unit 2 (TMI-2) defueling canister, called a ''knockout'' canister, was subjected to a series of drop tests at the Oak Ridge National Laboratory's Drop Test Facility. These tests were designed to confirm the structural integrity of internal fixed neutron poisons in support of a request for NRC licensing of this type of canister for the shipment of TMI-2 reactor fuel debris to the Idaho National Engineering Laboratory (INEL) for the Core Examination R and D Program. Work conducted at the Oak Ridge National Laboratory included (1) precise physical measurements of the internal poison rod configuration before assembly, (2) canister assembly and welding, (3) nondestructive examination (an initial hydrostatic pressure test and an x-ray profile of the internals before and after each drop test), (4) addition of a simulated fuel load, (5) instrumentation of the canister for each drop test, (6) fabrication of a cask simulation vessel with a developed and tested foam impact limiter, (7) use of refrigeration facilities to cool the canister to well below freezing prior to three of the drops, (8) recording the drop test with still, high-speed, and normal-speed photography, (9) recording the accelerometer measurements during impact, (10) disassembly and post-test examination with precise physical measurements, and (11) preparation of the final report.

  8. Thermodynamic performance testing of the orbiter flash evaporator system

    NASA Technical Reports Server (NTRS)

    Jaax, J. R.; Melgares, M. A.; Frahm, J. P.

    1980-01-01

    System level testing of the space shuttle orbiter's development flash evaporator system (FES) was performed in a thermal vacuum chamber capable of simulating ambient ascent, orbital, and entry temperature and pressure profiles. The test article included the evaporator assembly, high load and topping exhaust duct and nozzle assemblies, and feedwater supply assembly. Steady state and transient heat load, water pressure/temperature and ambient pressure/temperature profiles were imposed by especially designed supporting test hardware. Testing in 1978 verified evaporator and duct heater thermal design, determined FES performance boundaries, and assessed topping evaporator plume characteristics. Testing in 1979 combined the FES with the other systems in the orbiter active thermal control subsystem (ATCS). The FES met or exceeded all nominal and contingency performance requirements during operation with the integrated ATCS. During both tests stability problems were encountered during steady state operations which resulted in subsequent design changes to the water spray nozzle and valve plate assemblies.

  9. Entrainment, Evaporation and Combustion of Drops in the Laminar Part of a Developing Mixing Layer

    NASA Technical Reports Server (NTRS)

    Fichot, F.; Bellan, J.; Harstad, K.

    1993-01-01

    A model is formulated in order to simulate the development of a sheer layer between a flow of air and a flow of fuel drops in a carrier gas. A characteristic feature of this type of flow is the interaction between the drop and the large-scale vortices produced the shear layer.

  10. 14 CFR 29.725 - Limit drop test.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ..., assuming that the mass of the rotorcraft acts at the center of gravity and exerts a force of 1.0g downward... acts at the center of gravity and exerts a force of 1g downward with the rotorcraft in the maximum nose... the drop test (i.e., the acceleration dv/dt in g's recorded in the drop test plus 1.0)....

  11. Vertical Drop Testing and Simulation of Anthropomorphic Test Devices

    NASA Technical Reports Server (NTRS)

    Polanco, Michael A.; Littell, Justin D.

    2011-01-01

    A series of 14 vertical impact tests were conducted using Hybrid III 50th Percentile and Hybrid II 50th Percentile Anthropomorphic Test Devices (ATDs) at NASA Langley Research Center. The purpose of conducting these tests was threefold: to compare and contrast the impact responses of Hybrid II and Hybrid III ATDs under two different loading conditions, to compare the impact responses of the Hybrid III configured with a nominal curved lumbar spine to that of a Hybrid III configured with a straight lumbar spine, and to generate data for comparison with predicted responses from two commercially available ATD finite element models. The two loading conditions examined were a high magnitude, short duration acceleration pulse, and a low magnitude, long duration acceleration pulse, each created by using different paper honeycomb blocks as pulse shape generators in the drop tower. The test results show that the Hybrid III results differ from the Hybrid II results more for the high magnitude, short duration pulse case. The comparison of the lumbar loads for each ATD configuration show drastic differences in the loads seen in the spine. The analytical results show major differences between the responses of the two finite element models. A detailed discussion of possible sources of the discrepancies between the two analytical models is also provided.

  12. X-38 Drop Model: Testing Parafoil Landing System during Drop Tests

    NASA Technical Reports Server (NTRS)

    1995-01-01

    A 4-foot-long model of NASA's X-38, an experimental crew return vehicle, glides to earth after being dropped from a Cessna aircraft in late 1995. The model was used to test the ram-air parafoil landing system, which could allow for accurate and controlled landings of an emergency Crew Return Vehicle spacecraft returning to Earth. The X-38 Crew Return Vehicle (CRV) research project is designed to develop the technology for a prototype emergency crew return vehicle, or lifeboat, for the International Space Station. The project is also intended to develop a crew return vehicle design that could be modified for other uses, such as a joint U.S. and international human spacecraft that could be launched on the French Ariane-5 Booster. The X-38 project is using available technology and off-the-shelf equipment to significantly decrease development costs. Original estimates to develop a capsule-type crew return vehicle were estimated at more than $2 billion. X-38 project officials have estimated that development costs for the X-38 concept will be approximately one quarter of the original estimate. Off-the-shelf technology is not necessarily 'old' technology. Many of the technologies being used in the X-38 project have never before been applied to a human-flight spacecraft. For example, the X-38 flight computer is commercial equipment currently used in aircraft and the flight software operating system is a commercial system already in use in many aerospace applications. The video equipment for the X-38 is existing equipment, some of which has already flown on the space shuttle for previous NASA experiments. The X-38's primary navigational equipment, the Inertial Navigation System/Global Positioning System, is a unit already in use on Navy fighters. The X-38 electromechanical actuators come from previous joint NASA, U.S. Air Force, and U.S. Navy research and development projects. Finally, an existing special coating developed by NASA will be used on the X-38 thermal tiles to

  13. X-38 Drop Model: Used to Test Parafoil Landing System during Drop Tests

    NASA Technical Reports Server (NTRS)

    1995-01-01

    A 4-foot-long model of NASA's X-38, an experimental crew return vehicle, glides to earth after being dropped from a Cessna aircraft in late 1995. The model was used to test the ram-air parafoil landing system, which could allow for accurate and controlled landings of an emergency Crew Return Vehicle spacecraft returning to Earth. The X-38 Crew Return Vehicle (CRV) research project is designed to develop the technology for a prototype emergency crew return vehicle, or lifeboat, for the International Space Station. The project is also intended to develop a crew return vehicle design that could be modified for other uses, such as a joint U.S. and international human spacecraft that could be launched on the French Ariane-5 Booster. The X-38 project is using available technology and off-the-shelf equipment to significantly decrease development costs. Original estimates to develop a capsule-type crew return vehicle were estimated at more than $2 billion. X-38 project officials have estimated that development costs for the X-38 concept will be approximately one quarter of the original estimate. Off-the-shelf technology is not necessarily 'old' technology. Many of the technologies being used in the X-38 project have never before been applied to a human-flight spacecraft. For example, the X-38 flight computer is commercial equipment currently used in aircraft and the flight software operating system is a commercial system already in use in many aerospace applications. The video equipment for the X-38 is existing equipment, some of which has already flown on the space shuttle for previous NASA experiments. The X-38's primary navigational equipment, the Inertial Navigation System/Global Positioning System, is a unit already in use on Navy fighters. The X-38 electromechanical actuators come from previous joint NASA, U.S. Air Force, and U.S. Navy research and development projects. Finally, an existing special coating developed by NASA will be used on the X-38 thermal tiles to

  14. Particle Segregation at Contact Lines of Evaporating Colloidal Drops: Influence of the Substrate Wettability and Particle Charge-Mass Ratio.

    PubMed

    Noguera-Marín, Diego; Moraila-Martínez, Carmen L; Cabrerizo-Vílchez, Miguel A; Rodríguez-Valverde, Miguel A

    2015-06-23

    Segregation of particles during capillary/convective self-assembly is interesting for self-stratification in colloidal deposits. In evaporating drops containing colloidal particles, the wettability properties of substrate and the sedimentation of particles can affect their accumulation at contact lines. In this work we studied the size segregation and discrimination of charged particles with different densities. We performed in-plane particle counting at evaporating triple lines by using fluorescence confocal microscopy. We studied separately substrates with very different wettability properties and particles with different charge-mass ratios at low ionic strength. We used binary colloidal suspensions to compare simultaneously the deposition of two different particles. The particle deposition rate strongly depends on the receding contact angle of the substrate. We further observed a singular behavior of charged polystyrene particles in binary mixtures under "salt-free" conditions explained by the "colloidal Brazil nut" effect. PMID:26000909

  15. Vertical Drop Test of a YS-11 Fuselage Section

    NASA Astrophysics Data System (ADS)

    Minegishi, Masakatsu; Kumakura, Ikuo; Iwasaki, Kazuo; Shoji, Hirokazu; Yoshimoto, Norio; Terada, Hiroyuki; Sashikuma, Hirofumi; Isoe, Akira; Yamaoka, Toshihiro; Katayama, Noriaki; Hayashi, Toru; Akaso, Tetsuya

    The Structures and Materials Research Center of the National Aerospace Laboratory of Japan (NAL) and Kawasaki Heavy Industories, Ltd. (KHI) conducted a vertical drop test of a fuselage section cut from a NAMIC YS-11 transport airplane at NAL vertical drop test facility in December 2001. The main objectives of this program were to obtain background data for aircraft cabin safety by drop test of a full-scale fuselage section and to develop computational method for crash simulation. The test article including seats and anthropomorphic test dummies was dropped to a rigid impact surface at a velocity of 6.1 m/s (20 ft/s). The test condition and result were considered to be severe but potentially survivable. A finite element model of this test article was also developed using the explicit nonlinear transient-dynamic analysis code, LS-DYNA3D. An outline of analytical method and comparison of analysis result with drop test data are presented in this paper.

  16. 49 CFR 572.102 - Drop test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... this section, the peak resultant accelerations at the location of the accelerometers mounted in the... 225g, and not more than 275g. The acceleration/time curve for the test shall be unimodal to the extent that oscillations occurring after the main acceleration pulse are less than ten percent (zero to...

  17. 49 CFR 572.102 - Drop test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... this section, the peak resultant accelerations at the location of the accelerometers mounted in the... 225g, and not more than 275g. The acceleration/time curve for the test shall be unimodal to the extent that oscillations occurring after the main acceleration pulse are less than ten percent (zero to...

  18. Frictionally induced ignition processes in drop and skid tests

    SciTech Connect

    Dickson, Peter; Parker, Gary; Novak, Alan

    2010-01-01

    The standard LANL/Pantex drop and skid tests rely on subjective assessment of reaction violence to quantify the response of the charge, and completely miss nonpropagating hot-spot ignition sites. Additionally, large variations in test results have been observed, which we propose is due to a misunderstanding of the basic physical processes that lead to threshold ignition in these tests. The tests have been redesigned to provide control of these mechanisms and to permit direct observation of hot spots at the impact site, allowing us to follow the progression of the outcome as the drop height and ignition source density are varied. The results confirm that frictional interactions between high-melting-point solids are the dominant ignition mechanism, not just at the threshold, but in fact at all realistic drop heights.

  19. Theoretical and testing performance of an innovative indirect evaporative chiller

    SciTech Connect

    Jiang, Yi; Xie, Xiaoyun

    2010-12-15

    An indirect evaporative chiller is a device used to produce chilled water at a temperature between the wet bulb temperature and dew point of the outdoor air, which can be used in building HVAC systems. This article presents a theoretical analysis and practical performance of an innovative indirect evaporative chiller. First, the process of the indirect evaporative chiller is introduced; then, the matching characteristics of the process are presented and analyzed. It can be shown that the process that produces cold water by using dry air is a nearly-reversible process, so the ideal produced chilled water temperature of the indirect evaporative chiller can be set close to the dew point temperature of the chiller's inlet air. After the indirect evaporative chiller was designed, simulations were done to analyze the output water temperature, the cooling efficiency relative to the inlet dew point temperature, and the COP that the chiller can performance. The first installation of the indirect evaporative chiller of this kind has been run for 5 years in a building in the city of Shihezi. The tested output water temperature of the chiller is around 14-20 C, which is just in between of the outdoor wet bulb temperature and dew point. The tested COP{sub r,s} of the developed indirect evaporative chiller reaches 9.1. Compared with ordinary air conditioning systems, the indirect evaporative chiller can save more than 40% in energy consumption due to the fact that the only energy consumed is from pumps and fans. An added bonus is that the indirect evaporative chiller uses no CFCs that pollute to the aerosphere. The tested internal parameters, such as the water-air flow rate ratio and heat transfer area for each heat transfer process inside the chiller, were analyzed and compared with designed values. The tested indoor air conditions, with a room temperature of 23-27 C and relative humidity of 50-70%, proved that the developed practical indirect evaporative chiller successfully

  20. Static, Drop, and Flight Tests on Musselman Type Airwheels

    NASA Technical Reports Server (NTRS)

    Peck, William C; Beard, Albert P

    1932-01-01

    The purpose of this investigation was to obtain quantitative information on the shock-reducing and energy-dissipating qualities of a set of 30 by 13-6 Musselman type airwheels. The investigation consisted of static, drop, and flight tests. The static tests were made with inflation pressures of approximately 0, 5, 10, 15, 20, and 25 pounds per square inch and loadings up to 9,600 pounds. The drop tests were with the inflation pressures approximately 5, 10, 15, 20, and 25 pounds per square inch and loadings of 1,840, 2,440, 3,050, and 3,585 pounds. The flight tests were made with VE-7 airplane weighing 2,153 pounds, with the tires inflated to 5, 10, and 15 pounds per square inch. The landing gears used in conjunction with airwheels were practically rigid structures. The results of the tests showed that the walls of the tires carried a considerable portion of the load, each tire supporting a load of 600 pounds with a depression of approximately 6 inches. The shock-reducing qualities, under severe tests, and the energy dissipating characteristics of the tires, under all tests, were poor. The latter was evidenced by the rebound present in all landings made. In the severe drop tests, the free rebound reached as much as 60 per cent of the free drop. The results indicate that a shock-reducing and energy-dissipating mechanism should be used in conjunction with airwheels.

  1. 14 CFR 23.725 - Limit drop tests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... assumed wing lift to the airplane weight, but not more than 0.667. (c) The limit inertia load factor must... test. (e) The limit inertia load factor must be determined from the drop test in paragraph (b) of this... paragraph (e) may not be more than the limit inertia load factor used in the landing conditions in § 23.473....

  2. 14 CFR 23.725 - Limit drop tests.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... assumed wing lift to the airplane weight, but not more than 0.667. (c) The limit inertia load factor must... test. (e) The limit inertia load factor must be determined from the drop test in paragraph (b) of this... paragraph (e) may not be more than the limit inertia load factor used in the landing conditions in § 23.473....

  3. 14 CFR 23.725 - Limit drop tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... assumed wing lift to the airplane weight, but not more than 0.667. (c) The limit inertia load factor must... test. (e) The limit inertia load factor must be determined from the drop test in paragraph (b) of this... paragraph (e) may not be more than the limit inertia load factor used in the landing conditions in § 23.473....

  4. 14 CFR 23.725 - Limit drop tests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... assumed wing lift to the airplane weight, but not more than 0.667. (c) The limit inertia load factor must... test. (e) The limit inertia load factor must be determined from the drop test in paragraph (b) of this... paragraph (e) may not be more than the limit inertia load factor used in the landing conditions in § 23.473....

  5. Modeling evaporation of Jet A, JP-7 and RP-1 drops at 1 to 15 bars

    NASA Technical Reports Server (NTRS)

    Harstad, K.; Bellan, J.

    2003-01-01

    A model describing the evaportion of an isolated drop of a multicomponent fuel containing hundreds of species has been developed. The model is based on Continuous Thermodynamics concepts wherein the composition of a fuel is statistically described using a Probability Distribution Function (PDF).

  6. 14 CFR 27.725 - Limit drop test.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... reaction that would exist at the nose wheel, assuming that the mass of the rotorcraft acts at the center of..., assuming that the mass of the rotorcraft acts at the center of gravity and exerts a force of lg downward... introduced into the drop test by appropriate energy absorbing devices or by the use of an effective mass....

  7. 14 CFR 27.725 - Limit drop test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... reaction that would exist at the nose wheel, assuming that the mass of the rotorcraft acts at the center of..., assuming that the mass of the rotorcraft acts at the center of gravity and exerts a force of lg downward... introduced into the drop test by appropriate energy absorbing devices or by the use of an effective mass....

  8. 14 CFR 27.725 - Limit drop test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... reaction that would exist at the nose wheel, assuming that the mass of the rotorcraft acts at the center of..., assuming that the mass of the rotorcraft acts at the center of gravity and exerts a force of lg downward... introduced into the drop test by appropriate energy absorbing devices or by the use of an effective mass....

  9. LLNL small-scale drop-hammer impact sensitivity test

    SciTech Connect

    Simpson, L.R.; Foltz, M.F.

    1995-01-01

    Small-scale safety testing of explosives and other energetic materials is done to determine their sensitivity to various stimuli including friction, static spark, and impact. This testing is typically done to discover potential handling problems for either newly synthesized materials of unknown behavior or materials that have been stored for long periods of time. This report describes the existing ``ERL Type 12 Drop Weight Impact Sensitivity Apparatus``, or ``Drop Hammer Machine``, and the methods used to determine the impact sensitivity of energetic materials, Also discussed are changes made to both the machine and methods since the inception of impact sensitivity testing at LLNL in 1956. The accumulated data for the materials tested in not listed here, the exception being the discussion of those specific materials (primary calibrants: PETN, RDX, Comp-B3,and TNT; secondary calibrants: K-6, RX-26-AF, and TATB) used to calibrate the machine.

  10. Dynamically controlled deposition of colloidal nanoparticle suspension in evaporating drops using laser radiation.

    PubMed

    Ta, V D; Carter, R M; Esenturk, E; Connaughton, C; Wasley, T J; Li, J; Kay, R W; Stringer, J; Smith, P J; Shephard, J D

    2016-05-18

    Dynamic control of the distribution of polystyrene suspended nanoparticles in evaporating droplets is investigated using a 2.9 μm high power laser. Under laser radiation a droplet is locally heated and fluid flows are induced that overcome the capillary flow, and thus a reversal of the coffee-stain effect is observed. Suspension particles are accumulated in a localised area, one order of magnitude smaller than the original droplet size. By scanning the laser beam over the droplet, particles can be deposited in an arbitrary pattern. This finding raises the possibility for direct laser writing of suspended particles through a liquid layer. Furthermore, a highly uniform coating is possible by manipulating the laser beam diameter and exposure time. The effect is expected to be universally applicable to aqueous solutions independent of solutes (either particles or molecules) and deposited substrates. PMID:27094902

  11. Testing of the Multi-Fluid Evaporator Engineering Development Unit

    NASA Technical Reports Server (NTRS)

    Quinn, Gregory; O'Connor, Ed; Riga, Ken; Anderson, Molly; Westheimer, David

    2007-01-01

    Hamilton Sundstrand is under contract with the NASA Johnson Space Center to develop a scalable, evaporative heat rejection system called the Multi-Fluid Evaporator (MFE). It is being designed to support the Orion Crew Module and to support future Constellation missions. The MFE would be used from Earth sea level conditions to the vacuum of space. The current Shuttle configuration utilizes an ammonia boiler and flash evaporator system to achieve cooling at all altitudes. The MFE system combines both functions into a single compact package with significant weight reduction and improved freeze-up protection. The heat exchanger core is designed so that radial flow of the evaporant provides increasing surface area to keep the back pressure low. The multiple layer construction of the core allows for efficient scale up to the desired heat rejection rate. The full scale MFE prototype will be constructed with four core sections that, combined with a novel control scheme, manage the risk of freezing the heat exchanger cores. A sub-scale MFE engineering development unit (EDU) has been built, and is identical to one of the four sections of a full scale prototype. The EDU has completed testing at Hamilton Sundstrand. The overall test objective was to determine the thermal performance of the EDU. The first set of tests simulated how each of the four sections of the prototype would perform by varying the chamber pressure, evaporant flow rate, coolant flow rate and coolant temperature. A second set of tests was conducted with an outlet steam header in place to verify that the outlet steam orifices prevent freeze-up in the core while also allowing the desired thermal turn-down ratio. This paper discusses the EDU tests and results.

  12. The effects of surfactant dynamics on deposition patterns in evaporating colloidal drops

    NASA Astrophysics Data System (ADS)

    Jung, Narina; Seo, Haewon; Kim, Pilwon; Yoo, Chun Sang

    Evaporation of a colloidal droplet typically leaves ring-like deposit patterns on a substrate, now well-known as the coffee ring effect. We investigate the effect of surfactant dynamics on the deposition process in a drying droplet. A coarse grained model has been developed to simulate cases with Marangoni stresses, adsorption kinetics, and intermolecular interaction of surfactant particles and to examine the related deposit formation of colloidal particles. By using the two-dimensional lattice for the lateral cross-section of a droplet, we are able to capture the full dynamics of recirculating flows with surfactant and colloidal particles during drying. The roles of surfactant on droplet and colloidal particle dynamics are investigated by systematically varying parameters, such as the maximum area fraction and the initial concentration of surfactant. We further highlight important factors to generate Marangoni eddies. This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIP) (No. 2015R1A2A2A01007378).

  13. Development of the Sasquatch Drop Test Footprint Tool

    NASA Technical Reports Server (NTRS)

    Bledsoe, Kristin J.

    2011-01-01

    The Crew Exploration Vehicle Parachute Assembly System (CPAS) is the parachute system for NASA s Orion spacecraft. CPAS is currently in the design and testing phase of development. The test program consists of numerous drop tests, wherein a test article rigged with parachutes is extracted or released from an aircraft. During such tests, range safety is paramount, as is the recoverability of the parachutes and test article. It is crucial to establish an aircraft release point that will ensure that the article and all items released from it will land in safe locations. Early in the CPAS project, a legacy tool (previously used on the X-38 project) was used to determine a safe release point and to predict the landing locations (the footprint) of the payload and all released objects. Due to increasing test complexity and the need for a more flexible tool, a new footprint predictor tool, called Sasquatch, was created in MATLAB. This tool takes in a simulated trajectory for the test article, information about all released objects, and atmospheric wind data (simulated or actual) to calculate the trajectories of the released objects. Dispersions are applied to the landing locations of those objects, taking into account the variability of winds, aircraft release point, and object descent rate. A safe aircraft release point is determined based on the landing locations of the payload and released objects. The release point, landing locations, and dispersions are plotted on a simple map of the drop zone for easy reference. To date, Sasquatch has been used for thirteen drop tests. Comparing the predictions with actual test results has allowed for significant improvements in the tool s predictive capabilities, especially the incorporation of a well-correlated horizontal throw model. Intended future improvements to the tool include tighter dispersions on the landing locations, Monte Carlo capability, direct input from trajectory simulations, and a graphical user interface.

  14. Coefficient of restitution of sports balls: A normal drop test

    NASA Astrophysics Data System (ADS)

    Haron, Adli; Ismail, K. A.

    2012-09-01

    Dynamic behaviour of bodies during impact is investigated through impact experiment, the simplest being a normal drop test. Normally, a drop test impact experiment involves measurement of kinematic data; this includes measurement of incident and rebound velocity in order to calculate a coefficient of restitution (COR). A high speed video camera is employed for measuring the kinematic data where speed is calculated from displacement of the bodies. Alternatively, sensors can be employed to measure speeds, especially for a normal impact where there is no spin of the bodies. This paper compares experimental coefficients of restitution (COR) for various sports balls, namely golf, table tennis, hockey and cricket. The energy loss in term of measured COR and effects of target plate are discussed in relation to the material and construction of these sports balls.

  15. 14 CFR 27.725 - Limit drop test.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... gravity and exerts a force of 1.0g downward and 0.25g forward. W=W T for tailwheel units (lbs.), equal to..., assuming that the mass of the rotorcraft acts at the center of gravity and exerts a force of lg downward..., during impact, on the mass used in the drop test (i.e., the acceleration dv/dt in g's recorded in...

  16. Seismic II over I Drop Test Program results and interpretation

    SciTech Connect

    Thomas, B.

    1993-03-01

    The consequences of non-seismically qualified (Category 2) objects falling and striking essential seismically qualified (Category 1) objects has always been a significant, yet analytically difficult problem, particularly in evaluating the potential damage to equipment that may result from earthquakes. Analytical solutions for impact problems are conservative and available for mostly simple configurations. In a nuclear facility, the [open quotes]sources[close quotes] and [open quotes]targets[close quotes] requiring evaluation are frequently irregular in shape and configuration, making calculations and computer modeling difficult. Few industry or regulatory rules are available on this topic even though it is a source of considerable construction upgrade costs. A drop test program was recently conducted to develop a more accurate understanding of the consequences of seismic interactions. The resulting data can be used as a means to improve the judgment of seismic qualification engineers performing interaction evaluations and to develop realistic design criteria for seismic interactions. Impact tests on various combinations of sources and targets commonly found in one Savannah River Site (SRS) nuclear facility were performed by dropping the sources from various heights onto the targets. This report summarizes results of the Drop Test Program. Force and acceleration time history data are presented as well as general observations on the overall ruggedness of various targets when subjected to impacts from different types of sources.

  17. Seismic II over I Drop Test Program results and interpretation

    SciTech Connect

    Thomas, B.

    1993-03-01

    The consequences of non-seismically qualified (Category 2) objects falling and striking essential seismically qualified (Category 1) objects has always been a significant, yet analytically difficult problem, particularly in evaluating the potential damage to equipment that may result from earthquakes. Analytical solutions for impact problems are conservative and available for mostly simple configurations. In a nuclear facility, the {open_quotes}sources{close_quotes} and {open_quotes}targets{close_quotes} requiring evaluation are frequently irregular in shape and configuration, making calculations and computer modeling difficult. Few industry or regulatory rules are available on this topic even though it is a source of considerable construction upgrade costs. A drop test program was recently conducted to develop a more accurate understanding of the consequences of seismic interactions. The resulting data can be used as a means to improve the judgment of seismic qualification engineers performing interaction evaluations and to develop realistic design criteria for seismic interactions. Impact tests on various combinations of sources and targets commonly found in one Savannah River Site (SRS) nuclear facility were performed by dropping the sources from various heights onto the targets. This report summarizes results of the Drop Test Program. Force and acceleration time history data are presented as well as general observations on the overall ruggedness of various targets when subjected to impacts from different types of sources.

  18. Preliminary Drop Testing Results to Validate an Analysis Methodology for Accidental Drop Events of Containers for Radioactive Materials

    SciTech Connect

    Snow, Spencer David; Morton, Dana Keith; Rahl, Tommy Ervin; Ware, Arthur Gates

    2001-07-01

    The National Spent Nuclear Fuel Program, operating from the Idaho National Engineering and Environmental Laboratory (INEEL), developed the standardized Department of Energy (DOE) spent nuclear fuel (SNF) canister. During the development of this canister, more than twenty drop tests were completed, evaluating high strain behavior, puncture resistance, maintenance of containment, and other canister responses. Computer analyses of these drop-test specimens/canisters employed the ABAQUS/Explicit software. A pre-drop analysis was performed for each test specimen to predict the deformed shape and resulting material straining. Typically, a postdrop analysis was also performed to better match actual test specifics (actual impact angle, test specimen material properties, etc.). The purpose for this analysis effort was to determine the capability of current analysis techniques to accurately predict the deformed shape of a standardized DOE SNF canister subjected to a defined drop event, without actually having to perform a drop test for every drop event of interest. Those analytical efforts yielded very accurate predictions for nearly all of the drop tests. However, it was noted, during one small-scale test, that the calculated deformed shape of the test specimen depended on the modeled frictional behavior as it impacted the essentially unyielding flat surface. In order to calculate the correct deformed shape, the modeled frictional behavior had to be changed to an unanticipated value. This paper will report the results of a preliminary investigation that determined the appropriate frictional modeling for a variety of impact angles. That investigation included drop testing performed at the INEEL from September 2000 to January 2001.

  19. Preliminary Results of Testing of Flow Effects on Evaporator Scaling

    SciTech Connect

    Hu, M.Z.

    2002-02-15

    This investigation has focused on the effects of fluid flow on solids deposition from solutions that simulate the feed to the 2H evaporator at the Savannah River Site. Literature studies indicate that the fluid flow (or shear) affects particle-particle and particle-surface interactions and thus the phenomena of particle aggregation in solution and particle deposition (i.e., scale formation) onto solid surfaces. Experimental tests were conducted with two configurations: (1) using a rheometer to provide controlled shear conditions and (2) using controlled flow of reactive solution through samples of stainless steel tubing. All tests were conducted at 80 C and at high silicon and aluminum concentrations, 0.133 M each, in solutions containing 4 M sodium hydroxide and 1 A4 each of sodium nitrate and sodium nitrite. Two findings from these experiments are important for consideration in developing approaches for reducing or eliminating evaporator scaling problems: (1) The rheometer tests suggested that for the conditions studied, maximum solids deposition occurs at a moderate shear rate, approximately 12 s{sup -1}. That value is expected to be on the order of shear rates that will occur in various parts of the evaporator system; for instance, a 6 gal/min single-phase liquid flow through the 2-in. lift or gravity drain lines would result in a shear rate of approximately 16 s{sup -1}. These results imply that engineering approaches aimed at reducing deposits through increased mixing would need to generate shear near all surfaces significantly greater than 12 s{sup -1}. However, further testing is needed to set a target value for shear that is applicable to evaporator operation. This is because the measured trend is not statistically significant at the 95% confidence interval due to variability in the results. In addition, testing at higher temperatures and lower concentrations of aluminum and silicon would more accurately represent conditions in the evaporator. Without

  20. Long Duration Testing of a Spacesuit Water Membrane Evaporator Prototype

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Makinen, Janice; Cox, Marlon; Watts, Carly; Campbell, Colin; Vogel, Matthew; Colunga, Aaron; Conger, Bruce

    2012-01-01

    The Spacesuit Water Membrane Evaporator (SWME) is a heat-rejection device that is being developed to perform thermal control for advanced spacesuits. Cooling is achieved by circulating water from the liquid cooling garment (LCG) through hollow fibers (HoFi s), which are small hydrophobic tubes. Liquid water remains within the hydrophobic tubes, but water vapor is exhausted to space, thereby removing heat. A SWME test article was tested over the course of a year, for a total of 600 cumulative hours. In order to evaluate SWME tolerance to contamination due to constituents caused by distillation processes, these constituents were allowed to accumulate in the water as evaporation occurred. A test article was tested over the course of a year for a total of 600 cumulative hours. The heat rejection performance of the SWME degraded significantly--below 700 W, attributable to the accumulation of rust in the circulating loop and biofilm growth. Bubble elimination capability, a feature that was previously proven with SWME, was compromised during the test, most likely due to loss of hydrophobic properties of the hollow fibers. The utilization of water for heat rejection was shown not to be dependent on test article, life cycle, heat rejection rate, or freezing of the membranes.

  1. Long Duration Testing of a Spacesuit Water Membrane Evaporator Prototype

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Makinen, Janice; Cox, Marlon; Watts, Carly; Campbell, Colin; Vogel, Matthew; Colunga, Aaron

    2011-01-01

    The Spacesuit Water Membrane Evaporator (SWME) is a heat-rejection device that is being developed to perform thermal control for advanced spacesuits. Cooling is achieved by circulating water from the liquid cooling garment (LCG) through hollow fibers (HoFi?s), which are small hydrophobic tubes. Liquid water remains within the hydrophobic tubes, but water vapor is exhausted to space, thereby removing heat. A SWME test article was tested over the course of a year, for a total of 1200 cumulative hours. In order to evaluate SWME tolerance to contamination due to constituents caused by distillation processes, these constituents were allowed to accumulate in the water as evaporation occurred. A test article was tested over the course of a year for a total of 1200 cumulative hours. The heat rejection performance of the SWME degraded significantly--below 700 W, attributable to the accumulation of rust in the circulating loop and biofilm growth. Bubble elimination capability, a feature that was previously proven with SWME, was compromised during the test, most likely due to loss of hydrophobic properties of the hollow fibers. The utilization of water for heat rejection was shown not to be dependent on test article, life cycle, heat rejection rate, or freezing of the membranes.

  2. Sheet Membrane Spacesuit Water Membrane Evaporator Thermal Test

    NASA Technical Reports Server (NTRS)

    Trevino, Luis A.; Bue, Grant C.

    2009-01-01

    For future lunar extravehicular activities (EVA), one method under consideration for rejecting crew and electronics heat involves evaporating water through a hydrophobic, porous Teflon(Registered Trademark) membrane. A Spacesuit Water Membrane Evaporator (SWME) prototype using this membrane was successfully tested by Ungar and Thomas (2001) with predicted performance matching test data well. The above referenced work laid the foundation for the design of a compact sheet membrane SWME development unit for use in the Constellation System Spacesuit Element Portable Life Support System (Vogel and et. al., ICES 2008). Major design objectives included minimizing mass, volume, and manufacturing complexity while rejecting a minimum of 810 watts of heat from water flowing through the SWME at 91 kg/hr with an inlet temperature of 291K. The design meeting these objectives consisted of three concentric cylindrical water channels interlaced with four water vapor channels. Two units were manufactured for the purpose of investigating manufacturing techniques and performing thermal testing. The extensive thermal test measured SWME heat rejection as a function of water inlet temperatures, water flow-rates, water absolute pressures, water impurities, and water vapor back-pressures. This paper presents the test results and subsequent analysis, which includes a comparison of SWME heat rejection measurements to pretest predictions. In addition, test measurements were taken such that an analysis of the commercial-off-the-shelf vapor pressure control valve could be performed.

  3. X-38 Drop Model: Landing Sequence Collage from Cessna Drop Test

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This sequence of photographs shows a 4-foot-long model of NASA's X-38 gliding to earth after being dropped from a Cessna aircraft in late 1995. The model was used to test the ram-air parafoil landing system, which could allow for accurate and controlled landings of an emergency Crew Return Vehicle spacecraft returning to earth. The X-38 Crew Return Vehicle (CRV) research project is designed to develop the technology for a prototype emergency crew return vehicle, or lifeboat, for the International Space Station. The project is also intended to develop a crew return vehicle design that could be modified for other uses, such as a joint U.S. and international human spacecraft that could be launched on the French Ariane-5 Booster. The X-38 project is using available technology and off-the-shelf equipment to significantly decrease development costs. Original estimates to develop a capsule-type crew return vehicle were estimated at more than $2 billion. X-38 project officials have estimated that development costs for the X-38 concept will be approximately one quarter of the original estimate. Off-the-shelf technology is not necessarily 'old' technology. Many of the technologies being used in the X-38 project have never before been applied to a human-flight spacecraft. For example, the X-38 flight computer is commercial equipment currently used in aircraft and the flight software operating system is a commercial system already in use in many aerospace applications. The video equipment for the X-38 is existing equipment, some of which has already flown on the space shuttle for previous NASA experiments. The X-38's primary navigational equipment, the Inertial Navigation System/Global Positioning System, is a unit already in use on Navy fighters. The X-38 electromechanical actuators come from previous joint NASA, U.S. Air Force, and U.S. Navy research and development projects. Finally, an existing special coating developed by NASA will be used on the X-38 thermal tiles to

  4. 30 CFR 35.22 - Test to determine effect of evaporation on flammability.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Test to determine effect of evaporation on... § 35.22 Test to determine effect of evaporation on flammability. (a) Purpose. The purpose of this test shall be to determine the effect of evaporation on the reduction of fire resistance of a hydraulic...

  5. 30 CFR 35.22 - Test to determine effect of evaporation on flammability.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Test to determine effect of evaporation on... § 35.22 Test to determine effect of evaporation on flammability. (a) Purpose. The purpose of this test shall be to determine the effect of evaporation on the reduction of fire resistance of a hydraulic...

  6. 30 CFR 35.22 - Test to determine effect of evaporation on flammability.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Test to determine effect of evaporation on... § 35.22 Test to determine effect of evaporation on flammability. (a) Purpose. The purpose of this test shall be to determine the effect of evaporation on the reduction of fire resistance of a hydraulic...

  7. 30 CFR 35.22 - Test to determine effect of evaporation on flammability.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Test to determine effect of evaporation on... § 35.22 Test to determine effect of evaporation on flammability. (a) Purpose. The purpose of this test shall be to determine the effect of evaporation on the reduction of fire resistance of a hydraulic...

  8. Digital antimicrobial susceptibility testing using the MilliDrop technology.

    PubMed

    Jiang, L; Boitard, L; Broyer, P; Chareire, A-C; Bourne-Branchu, P; Mahé, P; Tournoud, M; Franceschi, C; Zambardi, G; Baudry, J; Bibette, J

    2016-03-01

    We present the MilliDrop Analyzer (MDA), a droplet-based millifluidic system for digital antimicrobial susceptibility testing (D-AST), which enables us to determine minimum inhibitory concentrations (MICs) precisely and accurately. The MilliDrop technology was validated by using resazurin for fluorescence readout, for comparison with standard methodology, and for conducting reproducibility studies. In this first assessment, the susceptibility of a reference Gram-negative strain Escherichia coli ATCC 25922 to gentamicin, chloramphenicol, and nalidixic acid were tested by the MDA, VITEK®2, and broth microdilution as a reference standard. We measured the susceptibility of clinically relevant Gram-positive strains of Staphylococcus aureus to vancomycin, including vancomycin-intermediate S. aureus (VISA), heterogeneous vancomycin-intermediate S. aureus (hVISA), and vancomycin-susceptible S. aureus (VSSA) strains. The MDA provided results which were much more accurate than those of VITEK®2 and standard broth microdilution. The enhanced accuracy enabled us to reliably discriminate between VSSA and hVISA strains. PMID:26803821

  9. Spacewedge #3 Being Loaded onto Cessna for Drop Test

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Crew members load a Spacewedge subscale research model into a Cessna aircraft for flight testing in 1996. The Spacewedge was drop-launched from the Cessna and then glided back to a soft landing under a steerable parafoil. From October 1991 to December 1996, NASA Ames-Dryden Flight Research Facility (after 1994, the Dryden Flight Research Center, Edwards, California) conducted a research program know as the Spacecraft Autoland Project. This Project was designed to determine the feasibility of the autonomous recovery of a spacecraft using a ram-air parafoil system for the final stages of flight, including a precision landing. The Johnson Space Center and the U.S. Army participated in various phases of the program. The Charles Stark Draper Laboratory developed the software for Wedge 3 under contract to the Army. Four generic spacecraft (each called a Spacewedge or simply a Wedge) were built; the last one was built to test the feasibility of a parafoil for delivering Army cargoes. Technology developed during this program has applications for future spacecraft recovery systems, such as the X-38 Crew Return Vehicle demonstrator. The Spacewedge program demonstrated precision flare and landing into the wind at a predetermined location. The program showed that a flexible, deployable system using autonomous navigation and landing was a viable and practical way to recover spacecraft. NASA researchers conducted flight tests of the Spacewedge at three sites near Dryden, a hillside near Tehachapi, the Rogers Dry Lakebed at Edwards Air Force Base, and the California City Airport Drop Zone. During the first phase of testing 36 flights were made. Phase II consisted of 45 flights using a smaller parafoil. A third Phase of 34 flights was conducted primarily by the Army and resulted in the development of an Army guidance system for precision offset cargo delivery. The wedge used during the Army phase was not called a Spacewedge but simply a Wedge. The Spacewedge was a flattened

  10. Vertical drop test of a transport fuselage center section including the wheel wells

    NASA Technical Reports Server (NTRS)

    Williams, M. S.; Hayduk, R. J.

    1983-01-01

    A Boeing 707 fuselage section was drop tested to measure structural, seat, and anthropomorphic dummy response to vertical crash loads. The specimen had nominally zero pitch, roll and yaw at impact with a sink speed of 20 ft/sec. Results from this drop test and other drop tests of different transport sections will be used to prepare for a full-scale crash test of a B-720.

  11. Final Report: Drop Testing of Aged Stems on the SP981 Reservoir

    SciTech Connect

    White, M.B.

    1999-08-11

    Free fall drop testing of unloaded SP981 reservoirs was conducted by Savannah River Technology Center in the Materials Test Facility. The testing consisted of dropping eight aged and two unaged reservoirs on their stems at impact angles of 88 degrees and 70 degrees from heights of approximately 4 and 6 foot above a hardened steel surface.

  12. Vertical Drop Test of a YS-11 Fuselage Section (Part 2)

    NASA Astrophysics Data System (ADS)

    Iwasaki, Kazuo; Kumakura, Ikuo; Minegishi, Masakutsu; Shoji, Hirokazu; Yoshimoto, Norio; Miyaki, Hiromitsu; Terada, Hiroyuki; Isoe, Akira; Yamaoka, Toshihiro; Katayama, Noriaki; Hayashi, Toru; Akaso, Tetsuya; Kosaka, Hideyuki

    The Structures and Materials Research Center of the National Aerospace Laboratory of Japan (NAL) and Kawasaki Heavy Industries, Ltd. (KHI) conducted the 2nd vertical drop test of a fuselage section cut from a NAMC YS-11 transport airplane in July 2002. The main objective of this test program was to obtain background data for aircraft cabin safety by drop test of a full-scale fuselage section and to develop computational tool for crash simulation of aircraft fuselage structure. The test article including seats and anthropomorphic test dummies was dropped to a rigid impact surface by free-fall method at a velocity of 7.6m/s (25ft/s). The impact environment and the resultant response of the fuselage structure and the passenger dummies were considered to be severe but potentially survivable. A description of the results of the 1st drop test and the 2nd drop test is presented in this paper.

  13. Space Shuttle Solid Rocket Booster decelerator subsystem - Air drop test vehicle/B-52 design

    NASA Technical Reports Server (NTRS)

    Runkle, R. E.; Drobnik, R. F.

    1979-01-01

    The air drop development test program for the Space Shuttle Solid Rocket Booster Recovery System required the design of a large drop test vehicle that would meet all the stringent requirements placed on it by structural loads, safety considerations, flight recovery system interfaces, and sequence. The drop test vehicle had to have the capability to test the drogue and the three main parachutes both separately and in the total flight deployment sequence and still be low-cost to fit in a low-budget development program. The design to test large ribbon parachutes to loads of 300,000 pounds required the detailed investigation and integration of several parameters such as carrier aircraft mechanical interface, drop test vehicle ground transportability, impact point ground penetration, salvageability, drop test vehicle intelligence, flight design hardware interfaces, and packaging fidelity.

  14. Testing of a Miniature Loop Heat Pipe with Multiple Evaporators and Multiple Condensers for Space Applications

    NASA Technical Reports Server (NTRS)

    Nagano, Hosei; Ku, Jentung

    2006-01-01

    Thermal performance of a miniature loop heat pipe (MLHP) with two evaporators and two condensers is described. A comprehensive test program, including start-up, high power, low power, power cycle, and sink temperature cycle tests, has been executed at NASA Goddard Space Flight Center for potential space applications. Experimental data showed that the loop could start with heat loads as low as 2W. The loop operated stably with even and uneven evaporator heat loads, and even and uneven condenser sink temperatures. Heat load sharing between the two evaporators was also successfully demonstrated. The loop had a heat transport capability of l00W to 120W, and could recover from a dry-out by reducing the heat load to evaporators. Low power test results showed the loop could work stably for heat loads as low as 1 W to each evaporator. Excellent adaptability of the MLHP to rapid changes of evaporator power and sink temperature were also demonstrated.

  15. Internally damped, self-arresting vertical drop-weight impact test apparatus

    NASA Technical Reports Server (NTRS)

    Ambur, Damodar R. (Inventor); Prasad, Chunchu B. (Inventor); Stockum, Robert W. (Inventor)

    1996-01-01

    A vertical dropped-weight impact test machine has a dropped-weight barrel vertically supported on upper and lower support brackets. The dropped-weight barrel is chambered to receive a dropped-weight assembly having a latch pin at its upper end, a damping unit in the middle, and a tup at its lower end. The tup is adapted for gathering data during impact testing. The latch pin releasably engages a latch pin coupling assembly. The latch pin coupling assembly is attached to a winch via a halyard for raising and lowering the dropped-weight assembly. The lower end of the dropped-weight barrel is provided with a bounce-back arresting mechanism which is activated by the descending passage of the dropped-weight assembly. After striking the specimen, the dropped-weight assembly rebounds vertically and is caught by the bounce-back arresting mechanism. The damping unit of the dropped-weight assembly serves to dissipate energy from the rebounding dropped-weight assembly and prevents the dropped-weight assembly from rebounding from the self-arresting mechanism.

  16. Internally damped, self-arresting vertical drop-weight impact test apparatus

    NASA Technical Reports Server (NTRS)

    Ambur, Damodar R. (Inventor); Prasad, Chunchu B. (Inventor); Waters, Jr., William A. (Inventor); Stockum, Robert W. (Inventor); Water, Manfred A. (Inventor)

    1995-01-01

    A vertical dropped-weight impact test machine has a dropped-weight barrel vertically supported on upper and lower support brackets. The dropped-weight barrel is chambered to receive a dropped-weight assembly having a latch pin at its upper end, a damping unit in the middle, and a tup at its lower end. The tup is adapted for gathering data during impact testing. The latch pin releasably engages a latch pin coupling assembly. The latch pin coupling assembly is attached to a winch via a halyard for raising and lowering the dropped-weight assembly. The lower end of the dropped-weight barrel is provided with a bounce-back arresting mechanism which is activated by the descending passage of the dropped-weight assembly. After striking the specimen, the dropped-weight assembly rebounds vertically and is caught by the bounce-back arresting mechanism. The damping unit of the dropped-weight assembly serves to dissipate energy from the rebounding dropped-weight assembly and prevents the dropped-weight assembly from rebounding from the self-arresting mechanism.

  17. 30 CFR 35.22 - Test to determine effect of evaporation on flammability.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS FIRE-RESISTANT HYDRAULIC FLUIDS Test Requirements... shall be to determine the effect of evaporation on the reduction of fire resistance of a hydraulic...

  18. Simulating New Drop Test Vehicles and Test Techniques for the Orion CEV Parachute Assembly System

    NASA Technical Reports Server (NTRS)

    Morris, Aaron L.; Fraire, Usbaldo, Jr.; Bledsoe, Kristin J.; Ray, Eric; Moore, Jim W.; Olson, Leah M.

    2011-01-01

    The Crew Exploration Vehicle Parachute Assembly System (CPAS) project is engaged in a multi-year design and test campaign to qualify a parachute recovery system for human use on the Orion Spacecraft. Test and simulation techniques have evolved concurrently to keep up with the demands of a challenging and complex system. The primary simulations used for preflight predictions and post-test data reconstructions are Decelerator System Simulation (DSS), Decelerator System Simulation Application (DSSA), and Drop Test Vehicle Simulation (DTV-SIM). The goal of this paper is to provide a roadmap to future programs on the test technique challenges and obstacles involved in executing a large-scale, multi-year parachute test program. A focus on flight simulation modeling and correlation to test techniques executed to obtain parachute performance parameters are presented.

  19. Results of the first thirty foot drop test of the MOSAIK KfK cask

    SciTech Connect

    Sorenson, K.B.; Salzbrenner, R.; Wellman, G.; Uncapher, W.; Bobbe, J.

    1991-01-01

    The MOSAIK KfK cask, a ductile cast iron (DCI) nuclear material transportation cask donated to Sandia by Gesellschaft fur NuklearService (GNS), was drop tested on June 25, 1990 in Albuquerque, New Mexico. Conditions of the test were; a 30 ft. drop without impact limiters onto an unyielding target, cask metal temperature {minus}16F or below, and a 0.75 inch deep flaw machined into the cask wall at the location of the highest tensile stress. The drop test was successful as judged by inspection of the machined flaw which showed no crack initiation. This drop test, in the first in a series, was designed to demonstrate the viability of using a fracture mechanics approach to design cask fabricated from ferritic materials. In addition, the test demonstrated that a DCI cask can withstand severe impacts under accident-type conditions without failing in a brittle mode. The drop test parameters were designed to produce high decelerations and yield-level stresses in the cask wall. The measured rigid body deceleration was approximately 800 gs. This compares with decelerations of 100 to 300 gs for drop tests of casks with impact limiters. The time to peak load was 1.2 to 2.8 msec., compared to 20 to 40 msec for casks dropped with impact limiters. The maximum strain during the drop test was 1400 microstrain, which equates to a maximum tensile stress of about 37000 psi. This level of stress slightly exceeds the static yield strength and is about 80% of the dynamic yield strength. The test results of this initial drop test are discussed in detail in this paper.

  20. Simulated Waste Testing Of Glycolate Impacts On The 2H-Evaporator System

    SciTech Connect

    Martino, C. J.

    2013-08-13

    Glycolic acid is being studied as a total or partial replacement for formic acid in the Defense Waste Processing Facility (DWPF) feed preparation process. After implementation, the recycle stream from DWPF back to the high-level waste tank farm will contain soluble sodium glycolate. Most of the potential impacts of glycolate in the tank farm were addressed via a literature review, but several outstanding issues remained. This report documents the non-radioactive simulant tests impacts of glycolate on storage and evaporation of Savannah River Site high-level waste. The testing for which non-radioactive simulants could be used involved the following: the partitioning of glycolate into the evaporator condensate, the impacts of glycolate on metal solubility, and the impacts of glycolate on the formation and dissolution of sodium aluminosilicate scale within the evaporator. The following are among the conclusions from this work: Evaporator condensate did not contain appreciable amounts of glycolate anion. Of all tests, the highest glycolate concentration in the evaporator condensate was 0.38 mg/L. A significant portion of the tests had glycolate concentration in the condensate at less than the limit of quantification (0.1 mg/L). At ambient conditions, evaporator testing did not show significant effects of glycolate on the soluble components in the evaporator concentrates. Testing with sodalite solids and silicon containing solutions did not show significant effects of glycolate on sodium aluminosilicate formation or dissolution.

  1. Parachute Compartment Drop Test Vehicle for Testing the Crew Exploration Vehicle's Parachute Assembly System

    NASA Technical Reports Server (NTRS)

    Lubey, Daniel P.; Thiele, Sara R.; Gruseck, Madelyn L.; Evans, Carol T.

    2010-01-01

    Though getting astronauts safely into orbit and beyond has long been one of NASA?s chief goals, their safe return has always been equally as important. The Crew Exploration Vehicle?s (CEV) Parachute Assembly System (CPAS) is designed to safely return astronauts to Earth on the next-generation manned spacecraft Orion. As one means for validating this system?s requirements and testing its functionality, a test article known as the Parachute Compartment Drop Test Vehicle (PC-DTV) will carry a fully-loaded yet truncated CPAS Parachute Compartment (PC) in a series of drop tests. Two aerodynamic profiles for the PC-DTV currently exist, though both share the same interior structure, and both have an Orion-representative weight of 20,800 lbf. Two extraction methods have been developed as well. The first (Cradle Monorail System 2 - CMS2) uses a sliding rail technique to release the PC-DTV midair, and the second (Modified DTV Sled; MDS) features a much less constrained separation method though slightly more complex. The decision as to which aerodynamic profile and extraction method to use is still not finalized. Additional CFD and stress analysis must be undertaken in order to determine the more desirable options, though at present the "boat tail" profile and the CMS2 extraction method seem to be the favored options in their respective categories. Fabrication of the PC-DTV and the selected extraction sled is set to begin in early October 2010 with an anticipated first drop test in mid-March 2011.

  2. Multi-Terrain Vertical Drop Tests of a Composite Fuselage Section

    NASA Technical Reports Server (NTRS)

    Kellas, Sotiris; Jackson, Karen E.

    2008-01-01

    A 5-ft-diameter composite fuselage section was retrofitted with four identical blocks of deployable honeycomb energy absorber and crash tested on two different surfaces: soft soil, and water. The drop tests were conducted at the 70-ft. drop tower at the Landing and Impact Research (LandIR) Facility of NASA Langley. Water drop tests were performed into a 15-ft-diameter pool of water that was approximately 42-in. deep. For the soft soil impact, a 15-ft-square container filled with fine-sifted, unpacked sand was located beneath the drop tower. All drop tests were vertical with a nominally flat attitude with respect to the impact surface. The measured impact velocities were 37.4, and 24.7-fps for soft soil and water, respectively. A fuselage section without energy absorbers was also drop tested onto water to provide a datum for comparison with the test, which included energy absorbers. In order to facilitate this type of comparison and to ensure fuselage survivability for the no-energy-absorber case, the velocity of the water impact tests was restricted to 25-fps nominal. While all tests described in this paper were limited to vertical impact velocities, the implications and design challenges of utilizing external energy absorbers during combined forward and vertical impact velocities are discussed. The design, testing and selection of a honeycomb cover, which was required in soft surface and water impacts to transmit the load into the honeycomb cell walls, is also presented.

  3. Multi-terrain Vertical Drop Tests of a Composite Fuselage Section

    NASA Technical Reports Server (NTRS)

    Sotirios, Kellas; Jackson, Karen E.

    2008-01-01

    A 5-ft-diameter composite fuselage section was retrofitted with four identical blocks of deployable honeycomb energy absorber and crash tested on two different surfaces: soft soil, and water. The drop tests were conducted at the 70-ft. drop tower at the Landing and Impact Research (LandIR) Facility of NASA Langley. Water drop tests were performed into a 15-ft-diameter pool of water that was approximately 42-in. deep. For the soft soil impact, a 15-ft-square container filled with fine-sifted, unpacked sand was located beneath the drop tower. All drop tests were vertical with a nominally flat attitude with respect to the impact surface. The measured impact velocities were 37.4, and 24.7-fps for soft soil and water, respectively. A fuselage section without energy absorbers was also drop tested onto water to provide a datum for comparison with the test, which included energy absorbers. In order to facilitate this type of comparison and to ensure fuselage survivability for the no-energy-absorber case, the velocity of the water impact tests was restricted to 25-fps nominal. While all tests described in this paper were limited to vertical impact velocities, the implications and design challenges of utilizing external energy absorbers during combined forward and vertical impact velocities are discussed. The design, testing and selection of a honeycomb cover, which was required in soft surface and water impacts to transmit the load into the honeycomb cell walls, is also presented.

  4. Initial basalt target site selection evaluation for the Mars penetrator drop test

    NASA Technical Reports Server (NTRS)

    Bunch, T. E.; Quaide, W. L.; Polkowski, G.

    1976-01-01

    Potential basalt target sites for an air drop penetrator test were described and the criteria involved in site selection were discussed. A summary of the background field geology and recommendations for optimum sites are also presented.

  5. Drop Test Results for the Combustion Engineering Model No. ABB-2901 Fuel Pellet Package

    SciTech Connect

    Hafner, R S; Mok, G C; Hagler, L G

    2004-04-23

    The U.S. Nuclear Regulatory Commission (USNRC) contracted with the Packaging Review Group (PRG) at Lawrence Livermore National Laboratory (LLNL) to conduct a single, 30-ft shallow-angle drop test on the Combustion Engineering ABB-2901 drum-type shipping package. The purpose of the test was to determine if bolted-ring drum closures could fail during shallow-angle drops. The PRG at LLNL planned the test, and Defense Technologies Engineering Division (DTED) personnel from LLNL's Site-300 Test Group executed the plan. The test was conducted in November 2001 using the drop-tower facility at LLNL's Site 300. Two representatives from Westinghouse Electric Company in Columbia, South Carolina (WEC-SC); two USNRC staff members; and three PRG members from LLNL witnessed the preliminary test runs and the final test. The single test clearly demonstrated the vulnerability of the bolted-ring drum closure to shallow-angle drops-the test package's drum closure was easily and totally separated from the drum package. The results of the preliminary test runs and the 30-ft shallow-angle drop test offer valuable qualitative understandings of the shallow-angle impact.

  6. Converting Simulated Sodium-bearing Waste into a Single Solid Waste Form by Evaporation: Laboratory- and Pilot-Scale Test Results on Recycling Evaporator Overheads

    SciTech Connect

    Griffith, D.; D. L. Griffith; R. J. Kirkham; L. G. Olson; S. J. Losinski

    2004-01-01

    Conversion of Idaho National Engineering and Environmental Laboratory radioactive sodium-bearing waste into a single solid waste form by evaporation was demonstrated in both flask-scale and pilot-scale agitated thin film evaporator tests. A sodium-bearing waste simulant was adjusted to represent an evaporator feed in which the acid from the distillate is concentrated, neutralized, and recycled back through the evaporator. The advantage to this flowsheet is that a single remote-handled transuranic waste form is produced in the evaporator bottoms without the generation of any low-level mixed secondary waste. However, use of a recycle flowsheet in sodium-bearing waste evaporation results in a 50% increase in remote-handled transuranic volume in comparison to a non-recycle flowsheet.

  7. Space Shuttle Solid Rocket Booster Decelerator Subsystem Drop Test 3 - Anatomy of a failure

    NASA Technical Reports Server (NTRS)

    Runkle, R. E.; Woodis, W. R.

    1979-01-01

    A test failure dramatically points out a design weakness or the limits of the material in the test article. In a low budget test program, with a very limited number of tests, a test failure sparks supreme efforts to investigate, analyze, and/or explain the anomaly and to improve the design such that the failure will not recur. The third air drop of the Space Shuttle Solid Rocket Booster Recovery System experienced such a dramatic failure. On air drop 3, the 54-ft drogue parachute was totally destroyed 0.7 sec after deployment. The parachute failure investigation, based on analysis of drop test data and supporting ground element test results is presented. Drogue design modifications are also discussed.

  8. Drying drops of blood

    NASA Astrophysics Data System (ADS)

    Brutin, David; Sobac, Benjamin; Loquet, Boris; Sampol, José.

    2010-11-01

    The drying of a drop of human blood is fascinating by the complexity of the physical mechanisms that occur as well as the beauty of the phenomenon which has never been previously evidenced in the literature. The final stage of full blood evaporation reveals for a healthy person the same regular pattern with a good reproducibility. Other tests on anemia and hyperlipidemic persons were performed and presented different patterns. By means of digital camera, the influence of the motion of red blood cells (RBCs) which represent about 50% of the blood volume, is revealed as well as its consequences on the final stages of drying. The mechanisms which lead to the final pattern of dried blood drops are presented and explained on the basis of fluid and solid mechanics in conjunction with the principles of hematology. Our group is the first to evidence that the specific regular patterns characteristic of a healthy individual do not appear in a dried drop of blood from a person with blood disease. Blood is a complex colloidal suspension for which the flow motion is clearly non-Newtonian. When drops of blood evaporate, all the colloids are carried by the flow motion inside the drop and interact.

  9. Shuttle orbiter flash evaporator operational flight test performance

    NASA Technical Reports Server (NTRS)

    Nason, J. R.; Behrend, A. F., Jr.

    1982-01-01

    The Flash evaporator System (FES is part of the Shuttle Orbiter Active Thermal Control Subsystem. The FES provides total heat rejection for the vehicle Freon Coolant Loops during ascent and entry and supplementary heat rejection during orbital mission phases. This paper reviews the performance of the FES during the first two Shuttle orbital missions (STS-1 and STS-2). A comparison of actual mission performance against design requirements is presented. Mission profiles (including Freon inlet temperature and feedwater pressure transients), control temperature, and heat load variations are evaluated. Anomalies that occurred during STS-2 are discussed along with the procedures conducted, both in-flight and post-flight, to isolate the causes. Finally, the causes of the anomalies and resulting corrective action taken for STS-3 and subsequent flights are presented.

  10. Droplet combustion experiment drop tower tests using models of the space flight apparatus

    NASA Technical Reports Server (NTRS)

    Haggard, J. B.; Brace, M. H.; Kropp, J. L.; Dryer, F. L.

    1989-01-01

    The Droplet Combustion Experiment (DCE) is an experiment that is being developed to ultimately operate in the shuttle environment (middeck or Spacelab). The current experiment implementation is for use in the 2.2 or 5 sec drop towers at NASA Lewis Research Center. Initial results were reported in the 1986 symposium of this meeting. Since then significant progress was made in drop tower instrumentation. The 2.2 sec drop tower apparatus, a conceptual level model, was improved to give more reproducible performance as well as operate over a wider range of test conditions. Some very low velocity deployments of ignited droplets were observed. An engineering model was built at TRW. This model will be used in the 5 sec drop tower operation to obtain science data. In addition, it was built using the flight design except for changes to accommodate the drop tower requirements. The mechanical and electrical assemblies have the same level of complexity as they will have in flight. The model was tested for functional operation and then delivered to NASA Lewis. The model was then integrated into the 5 sec drop tower. The model is currently undergoing initial operational tests prior to starting the science tests.

  11. 14 CFR 29.725 - Limit drop test.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., assuming that the mass of the rotorcraft acts at the center of gravity and exerts a force of 1.0g downward... energy absorbing devices or by the use of an effective mass. (c) Each landing gear unit must be tested in... to be absorbed by it. (d) When an effective mass is used in showing compliance with paragraph (b)...

  12. 14 CFR 29.725 - Limit drop test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., assuming that the mass of the rotorcraft acts at the center of gravity and exerts a force of 1.0g downward... energy absorbing devices or by the use of an effective mass. (c) Each landing gear unit must be tested in... to be absorbed by it. (d) When an effective mass is used in showing compliance with paragraph (b)...

  13. Validation and reliability assessment of board level drop test of chip-scale-packaging

    NASA Astrophysics Data System (ADS)

    Hung, Tuan-Yu; Chou, Chan-Yen; Yew, Ming-Chih; Chiang, Kuo-Ning

    2008-11-01

    The main objective of this study is to develop a stress-buffer-improved package that is subjected to a board level drop test under a specific-G impact level. In this regard, both the drop test experiment and the ANSYS/LS-DYNA simulations are carried out. Several studies have shown that the solder joints having the brittle intermetallic compound (IMC) layers within the wafer level chip scale packaging (WLCSP) are the weakest part. For the most part, this is due to the large relative motion occurring between the board and the chip. In addition, the stress buffer layer exhibiting a relatively large elongation which reduces the impact on the solder balls. Meanwhile, the novel stress-buffer-improve package's failure mode is different from the convention WLCSP structure which shifts to the trace damage of the chip side. The leading concern between the solder ball and trace damage is the critical region where failure occurred owing to the stress concentration effect. During the drop test experiment, the proposed stress-buffer-improved package is able to survive over 100 drops (most packages survived at above 200 drops). Hence, this drop performance very much surpasses the Joint Electron Device Engineering Council (JEDEC) criterion (drop number is 30 times). Nevertheless, the metal traces which are embedded in the stress buffer layer suffered relatively larger deformation. Generally, the stress concentration occurs at a single position, much like the trace/pad connecting junction in the analysis of detailed stress-buffer-improved package. Finally, the predict result in finite element (FE) analysis is similar to the broken metal trace's failure analysis in the drop test experiment.

  14. Max Launch Abort System (MLAS) Landing Parachute Demonstrator (LPD) Drop Test

    NASA Technical Reports Server (NTRS)

    Shreves, Christopher M.

    2011-01-01

    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. Desktop Application Program to Simulate Cargo-Air-Drop Tests

    NASA Technical Reports Server (NTRS)

    Cuthbert, Peter

    2009-01-01

    The DSS Application is a computer program comprising a Windows version of the UNIX-based Decelerator System Simulation (DSS) coupled with an Excel front end. The DSS is an executable code that simulates the dynamics of airdropped cargo from first motion in an aircraft through landing. The bare DSS is difficult to use; the front end makes it easy to use. All inputs to the DSS, control of execution of the DSS, and postprocessing and plotting of outputs are handled in the front end. The front end is graphics-intensive. The Excel software provides the graphical elements without need for additional programming. Categories of input parameters are divided into separate tabbed windows. Pop-up comments describe each parameter. An error-checking software component evaluates combinations of parameters and alerts the user if an error results. Case files can be created from inputs, making it possible to build cases from previous ones. Simulation output is plotted in 16 charts displayed on a separate worksheet, enabling plotting of multiple DSS cases with flight-test data. Variables assigned to each plot can be changed. Selected input parameters can be edited from the plot sheet for quick sensitivity studies.

  16. Validation of drop plate technique for bacterial enumeration by parametric and nonparametric tests

    PubMed Central

    Naghili, Hossein; Tajik, Hossein; Mardani, Karim; Razavi Rouhani, Seyed Mehdi; Ehsani, Ali; Zare, Payman

    2013-01-01

    Drop plate technique has a priority and preference compared with the spread plate procedure, because of less time, quantity of media, effort requirement, little incubator space, and less labor intensive. The objective of this research was to compare the accuracy and fidelity of drop plate method vs. spread plate method by parametric and nonparametric statistical tests. For bacterial enumeration by drop and spread plate methods, successive dilutions of second subculture of Lactobacillus casei and Salmonella Typhimurium were transferred to selective agar. The correlation of agreement between both methods was evaluated by using statistical proofs. Results showed that mean value (parametric unpaired t-test) comparison at 95 percent confidence level did not reject null hypothesis, which it meant that the equality of the mean data could not be ruled out. Nonparametric method was used because of approximately Gaussian pattern of data distribution. For this purpose, Mann-Whitney test (equivalent nonparametric t-test) was used. It meant that the equality of medians obtained from two methods were similar. Spearman’s rho correlation coefficient (r) via both methods due to data distribution patterns for enumeration of S. Typhimurium and L. casei were 0.62 and 0.87, respectively; which represented moderately strong and strong relationship between two methods, respectively. Besides, there was a significant and strong positive correlation (p < 0.001) between spread and drop plate procedures. Because of aforementioned reasons, the spread plate method can be replaced by drop plate method. PMID:25653794

  17. Testing of a Loop Heat Pipe with Two Evaporators and Two Condensers

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Birur, Gaj; Powers, Edward I. (Technical Monitor)

    2001-01-01

    Most existing Loop Heat Pipes (LHPs) consist of one single evaporator and one single condenser. LHPs with multiple evaporators will be very desirable for cooling multiple heat sources or a heat source with large thermal footprints. Extending the LHP technology to include multiple evaporators and multiple condensers faces some challenges, including the interaction between individual compensation chambers, operating temperature stability, and adaptability to rapid power and sink temperature transients. This paper describe extensive testing of an LHP with two evaporators and two condensers. Tests performed include start-up, power cycle, sink temperature cycle, reservoir temperature cycle, and capillary limit. Test results showed that the loop could operate successfully under various heat load and sink conditions. The loop operating temperature is a function of the total heat load, the heat load distribution between the two evaporators, and temperatures of the two condenser sinks. Under most conditions, only one reservoir contained two-phase fluid and the other reservoir was completely liquid filled. Moreover, control of the loop operating temperature could shift from one reservoir to the other as the test condition changed.

  18. Surface composition and barium evaporation rate of ``pedigreed'' impregnated tungsten dispenser cathodes during accelerated life testing

    NASA Astrophysics Data System (ADS)

    Tomich, D. H.; Mescher, J. A.; Grant, J. T.

    1987-03-01

    A study has been made of the surface composition and barium evaporation rate of "pedigreed" impregnated tungsten dispenser cathodes. The effect of air exposure on coated cathodes was examined and was found to have no significant effect on barium evaporation rate although in some cases longer reactivation times were required. No changes in surface topography were apparent following air exposure and reactivation. Life testing was done at 100°C above the typical operating temperature for the cathode, where the typical operating temperature was taken to be 950°C for coated cathodes and 1050°C for uncoated cathodes. The cathodes were examined at different stages of life testing, up to 1200 h. Significant decreases in barium evaporation rates were found after as few as 500 h of life testing. After 1000 h the evaporation rate had decreased more than an order of magnitude. Changes in surface composition were also found. The effects of tungsten particle size, used in manufacture of the billet, on barium evaporation rate were also studied but no correlation was found.

  19. Design, manufacture, and testing of the Armstrong Hall drop tower decelerator

    NASA Astrophysics Data System (ADS)

    Ocampo, Jaime Andres

    A decelerator was needed for the Armstrong Hall Microgravity tower. Three designs were considered as concepts and the one chosen was an airbag. The airbag is 5 feet tall and 4.5 feet in diameter due to floor constraints. The deceleration was controlled by designing the vent system to provide the needed vent area as a function of time. This dynamics vent area controls the rate at which volume is expelled from the airbag. The volume expelled depends on the pressure inside the airbag, thus, a direct relation between the vent area and the deceleration profile was determined. The airbag and associated infrastructure was designed, manufactured, and tested. This system includes an airbag with a cushion on top to prevent wear, cart and rails, a drop package, and a latch and release system. More than forty tests were done with different drop height and drop weight combinations culminating in three drops of 200 lbs from the third floor. The drop weight was varied by adjusting the water level in a plastic barrel in the drop package. Pressure measurements inside the bag and vent were taken using two pressure transducers. The pressure transducers sampled the pressure at one of the exit vents and at the center of the bottom of the airbag. The signals were low-pass filtered for noise and scaled for pressure. The pressure traces were processed to find the mean deceleration. The deceleration was found to be independent of drop weight, only depending on drop height. The traces were also integrated to find a momentum per unit area. This value was then compared to the momentum of the drop package. From these two results an effective impact area can be found. It was found that the cushion not only reduced wear but also increased the effective impact area substantially. This increase in area reduced the value of the mean deceleration by reducing the pressure inside the airbag. The airbag proved to work well for the drops, decelerating the package and preventing a direct hit with the

  20. Drop Test Results for the Combustion Engineering Model No. ABB-2901 Fuel Pellet Shipping Package

    SciTech Connect

    Mok, G; Hagler, L

    2002-06-01

    Steel cylindrical drums have been used for many years to transport radioactive materials. The radioactive material inserted into the drum cavity for shipping is usually restrained within its own container or containment vessel. For additional protection, the container is surrounded or supported by components made of impact-absorbent and/or thermal-insulation materials. The components are expected to protect the container and its radioactive contents under severe transportation conditions like free drops and fires. Due to its simplicity and convenience, bolted-ring drum closures are commonly used to close many drum packages. Because the structural integrity of the drum and drum closure often play a significant role in determining the package's ability to maintain sub-criticality, shielding, and containment of the radioactive contents, regulations require that the complete drum package be tested for safety performance. The structural integrity of the drum body is relatively simple to understand and analyze, whereas analyzing the integrity of the drum closure is not so simple. In summary, the drop test accomplished its mission. Because the lid and closure device separated from the drum body in the 30-ft 17.5{sup o} shallow-angle drop, the drop test confirmed that the common drum closure with a bolted ring is vulnerable to damage by a shallow-angle drop, even though the closure has been shown to survive much steeper-angle drops. The test program also demonstrated one of the mechanisms by which the shallow-angle drop opens the common bolted-ring drum closure. The separation of the drum lid and closure device from the drum body was initiated by a large outward buckling deformation of the lid and completed with minimal assistance by the round plywood boards behind the lid. The energy spent to complete the separation appeared to be only a small fraction of the total impact energy. Limited to only one test, the present test program could not explore all possible mechanisms

  1. Drop-test study of parachute textile with embedded fiber optic sensors

    NASA Astrophysics Data System (ADS)

    Li, Min; Li, Yulin

    2005-04-01

    We developed here a novel embedded strain measurement system that fulfilled a dynamic analysis of the characteristics of parachute canopy based on fiber optics technology. As a continue study of the dynamic characteristics of the parachute canopy, a series of drop tests were developed in the laboratory, and followed by the field test. Sample results obtained by both mode power distribution (MPD) system and fiber Bragg grating (FBG) sensors are taken into the comparison between the optical and mechanical testing results. Drop test results from both MPD and FBG sensors were analysis and correlated to the mechanical characteristics of the parachute canopy textile based on the previous relatins derived from quasi-static test. The curves show clearly that the results of the two types of sensors are consistent. The achieved results provided a nice correlation between the optical and mechanical signals, which dues primarily to the model built up in previous quasi-static test, and will be discussed in this paper.

  2. Results from evaporation tests to support the MWTF heat removal system design

    SciTech Connect

    Crea, B.A.

    1994-12-22

    An experimental tests program was conducted to measure the evaporative heat removal from the surface of a tank of simulated waste. The results contained in this report constitute definition design data for the latest heat removal function of the MWTF primary ventilation system.

  3. Crash Simulation of a Boeing 737 Fuselage Section Vertical Drop Test

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Jackson, Karen E.; Jones, Yvonne T.; Frings, Gary; Vu, Tong

    2004-01-01

    A 30-ft/s vertical drop test of a fuselage section of a Boeing 737 aircraft was conducted in October of 1999 at the FAA Technical Center in Atlantic City, NJ. This test was performed to evaluate the structural integrity of a conformable auxiliary fuel tank mounted beneath the floor and to determine its effect on the impact response of the airframe structure and the occupants. The test data were used to compare with a finite element simulation of the fuselage structure and to gain a better understanding of the impact physics through analytical/experimental correlation. To perform this simulation, a full-scale 3-dimensional finite element model of the fuselage section was developed using the explicit, nonlinear transient-dynamic finite element code, MSC.Dytran. The emphasis of the simulation was to predict the structural deformation and floor-level acceleration responses obtained from the drop test of the B737 fuselage section with the auxiliary fuel tank.

  4. Vertical drop test of a transport fuselage section located forward of the wing

    NASA Technical Reports Server (NTRS)

    Williams, M. S.; Hayduk, R. J.

    1983-01-01

    A Boeing 707 fuselage section was drop tested at the NASA Langley Research Center to measure structural, seat, and occupant response to vertical crack loads. Post-test inspection showed that the section bottom collapsed inward approximately 2 ft. Preliminary data traces indicated maximum normal accelerations of 20 g on the fuselage bottom, 10 to 12 g on the cabin floor, and 6.5 to 8 g in the pelvises of the anthropomorphic dummies.

  5. Laboratory Evaporation Testing Of Hanford Waste Treatment Plant Low Activity Waste Off-Gas Condensate Simulant

    SciTech Connect

    Adamson, Duane J.; Nash, Charles A.; McCabe, Daniel J.; Crawford, Charles L.; Wilmarth, William R.

    2014-01-27

    (chloride, fluoride, sulfur), will have high ammonia, and will contain carryover particulates of glass-former chemicals. These species have potential to cause corrosion of tanks and equipment, precipitation of solids, release of ammonia gas vapors, and scale in the tank farm evaporator. Routing this stream to the tank farms does not permanently divert it from recycling into the WTP, only temporarily stores it prior to reprocessing. Testing is normally performed to demonstrate acceptable conditions and limits for these compounds in wastes sent to the tank farms. The primary parameter of this phase of the test program was measuring the formation of solids during evaporation in order to assess the compatibility of the stream with the evaporator and transfer and storage equipment. The origin of this LAW Off-Gas Condensate stream will be the liquids from the Submerged Bed Scrubber (SBS) and the Wet Electrostatic Precipitator (WESP) from the LAW facility melter offgas system. The stream is expected to be a dilute salt solution with near neutral pH, and will likely contain some insoluble solids from melter carryover. The soluble components are expected to be mostly sodium and ammonium salts of nitrate, chloride, and fluoride. This stream has not been generated yet, and, thus, the composition will not be available until the WTP begins operation, but a simulant has been produced based on models, calculations, and comparison with pilot-scale tests. This report discusses results of evaporation testing of the simulant. Two conditions were tested, one with the simulant at near neutral pH, and a second at alkaline pH. The neutral pH test is comparable to the conditions in the Hanford Effluent Treatment Facility (ETF) evaporator, although that evaporator operates at near atmospheric pressure and tests were done under vacuum. For the alkaline test, the target pH was based on the tank farm corrosion control program requirements, and the test protocol and equipment was comparable to that

  6. Analytical Evaluation of Drop Tests Performed on Nine 18-Inch Diameter Standardized DOE Spent Nuclear Fuel Canisters

    SciTech Connect

    Snow, Spencer David; Morton, Dana Keith; Rahl, Tommy Ervin; Ware, Arthur Gates; Smith, Nancy Lynn

    2000-07-01

    During fiscal year 1999, a total of nine 18-inch diameter test canisters were fabricated at the Idaho National Engineering & Environmental Laboratory (INEEL) to represent the standardized Department of Energy (DOE) Spent Nuclear Fuel (SNF) canister design. Various "worst case" internal loadings were incorporated. Seven of the test canisters were 15-foot long and weighed approximately 6000 pounds, while two were 10-foot long and weighed 3000 and 3800 pounds. Seven of the test canisters were dropped from thirty feet onto an essentially unyielding flat surface and one of the test canisters was dropped from 40-inches onto a 6-inch diameter puncture post. The final test canister was dropped from 24 inches onto a 2-inch thick vertically oriented steel plate, and then tipped over to impact another 2-inch thick vertically oriented steel plate. This last test was attempting to represent a canister dropping onto another larger container such as a repository disposal container. All drop testing was performed at Sandia National Laboratory (SNL). The nine test canisters experienced varying degrees of damage to their skirts, lifting rings, and pressure boundary components (heads and main body). However, all of the canisters were shown to have maintained their pressure boundary (through pressure testing), and the four worst damaged canisters were also shown to be leaktight (via helium leak testing performed at the INEEL). Pre-drop and post-drop test canister finite element modeling was performed at the INEEL in support of the canister drop test program. All model evaluations were performed using the ABAQUS/Explicit software. The finite element models representing the test canisters accurately (though at times, slightly conservatively) predicted the actual test canister responses during the defined drop events.This paper will discuss highlights of the drop testing program and will give detailed comparisons of analysis versus actual test results.

  7. Testing of a 4 K to 2 K heat exchanger with an intermediate pressure drop

    SciTech Connect

    Knudsen, Peter N.; Ganni, Venkatarao

    2015-12-01

    Most large sub-atmospheric helium refrigeration systems incorporate a heat exchanger at the load, or in the distribution system, to counter-flow the sub-atmospheric return with the super-critical or liquid supply. A significant process improvement is theoretically obtainable by handling the exergy loss across the Joule-Thompson throttling valve supplying the flow to the load in a simple but different manner. As briefly outlined in previous publications, the exergy loss can be minimized by allowing the supply flow pressure to decrease to a sub-atmospheric pressure concurrent with heat exchange flow from the load. One practical implementation is to sub-divide the supply flow pressure drop between two heat exchanger sections, incorporating an intermediate pressure drop. Such a test is being performed at Jefferson Lab's Cryogenic Test Facility (CTF). This paper will briefly discuss the theory, practical implementation and test results and analysis obtained to date.

  8. Design and testing of photonic band gap channel-drop-filters

    SciTech Connect

    Shchegolkov, Dmitry; Earley, Lawrence M; Health, Cynthia E; Smirnova, Evgenya I

    2009-01-01

    We have designed, fabricated and tested several novel passive mm-wave spectrometers based on Photonic Band Gap (PBG) structures. Our spectrometers were designed to operate in the frequency ranges of 90-130 and 220-300 GHz. We built and tested both metallic and dielectric silicon Channel-Drop-Filter (CDF) structures at 90-130 GHz. We are currently fabricating a dielectric CDF structure to operate at 220-300 GHz. The complete recent test results for the metal version and preliminary test results for the higher frequency silicon versions will be presented at the conference.

  9. Evaluation of malodor for automobile air conditioner evaporator by using laboratory-scale test cooling bench.

    PubMed

    Kim, Kyung Hwan; Kim, Sun Hwa; Jung, Young Rim; Kim, Man Goo

    2008-09-12

    As one of the measures to improve the environment in an automobile, malodor caused by the automobile air-conditioning system evaporator was evaluated and analyzed using laboratory-scale test cooling bench. The odor was simulated with an evaporator test cooling bench equipped with an airflow controller, air temperature and relative humidity controller. To simulate the same odor characteristics that occur from automobiles, one previously used automobile air conditioner evaporator associated with unpleasant odors was selected. The odor was evaluated by trained panels and collected with aluminum polyester bags. Collected samples were analyzed by thermal desorption into a cryotrap and subsequent gas chromatographic separation, followed by simultaneous olfactometry, flame ionization detector and identified by atomic emission detection and mass spectrometry. Compounds such as alcohols, aldehydes, and organic acids were identified as responsible odor-active compounds. Gas chromatography/flame ionization detection/olfactometry combined sensory method with instrumental analysis was very effective as an odor evaluation method in an automobile air-conditioning system evaporator. PMID:18701113

  10. Vertical Drop Testing and Analysis of the Wasp Helicopter Skid Gear

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fuchs, Yvonne T.

    2007-01-01

    This report describes an experimental program to assess the impact performance of a skid gear for use on the Wasp kit-built helicopter, which is marketed by HeloWerks, Inc. of Hampton, Virginia. In total, five vertical drop tests were performed. The test article consisted of a skid gear mounted beneath a steel plate. A seating platform was attached to the upper surface of the steel plate, and two 95th percentile Hybrid III male Anthropomorphic Test Devices (ATDs) were seated on the platform and secured using a four-point restraint system. The test article also included ballast weights to ensure the correct position of the Center-of-Gravity (CG). Twenty-six channels of acceleration data were collected per test at 50,000 samples per second. The five drop tests were conducted on two different gear configurations. The details of these test programs are presented, as well as an occupant injury assessment. Finally, a finite element model of the skid gear test article was developed for execution in LS-DYNA, an explicit nonlinear transient dynamic code, for predicting the skid gear and occupant dynamic responses due to impact.

  11. Syracuse University Test Report On Uptake Factor Resulting From A Dropped Storage Container

    SciTech Connect

    Gao, Z; Zhang, J S

    2010-09-01

    Under certain circumstances, powder from an accidently dropped container can become airborne and inhaled by people nearby such as those who are moving the containers. The inhaled fine particles can deposit on respiratory tracts and lungs, causing asthma, lung cancer, and other acute respiratory illnesses and chronic symptoms. The objective of this study was to develop a standard procedure to measure the airborne concentrations of different size particles within the vicinity of a dropped container where a significant portion of the contained powder is ejected. Tungsten oxide (WO{sub 3}) was selected in this study to represent relatively heavy powders (7.16 g/cm3 specific gravity for WO{sub 3}). A typical can with the outer dimensions of 4.25” diameter and 4.875” tall was used as the container. The powder was dropped in two different configurations: 1) contained within a can covered by a lid that has a 0.25” diameter hole, and 2) contained within a can without a lid. The packing volume of the powder was 51.4 in{sup 3} (842.7 cm{sup 3}) and the target mass was 1936 g. The tests were carried out in a full-scale stainless steel environmental chamber with an interior volume of 852 ft{sup 3} (24.1 m{sup 3}). The chamber system includes an internal recirculation loop with a rectangular air diffuser and 10 variable frequency drive fans to provide a typical room air recirculation flow pattern. Two air filters were installed in the chamber air supply duct and return duct to achieve the required low background particle concentration. The initial chamber air conditions were set at 70°F (± 5°F) and 50% (± 10%) RH. A supporting frame and releasing device were designed and built to trigger consistently the dropping of the can at a height of 8 feet from the bottom of the can to the impacting surface. The particle sampling inlet was placed 5 ft above the floor and 6 inches laterally away from the can’s falling path. Concentrations of particles between 0.5 μm and 20

  12. Convective Evaporation Of Sprayed Liquid

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Harstad, Kenneth G.

    1987-01-01

    Theoretical model developed to analyze behavior of both dense and dilute clusters of evaporating liquid drops in gas flows. Particularly useful in search for methods of controlling evaporation, ignition, and combustion of fuel sprays.

  13. Drop Tower Microgravity Improvement towards the nano-g Level for the MICROSCOPE Payload Tests

    NASA Astrophysics Data System (ADS)

    Selig, Hanns

    The Bremen drop tower at the Center of Applied Space Technology and Microgravity (ZARM) provides high quality micro-g condition needed for many high precision tests. This is even more improved by the development of a free flyer technology. This new technology is used for a free fall test of the MICROSCOPE differential accelerometers which only can work with a residual acceleration disturbance level below 25 nano-g in the high resolution mode. The French MICROSCOPE space mission for testing the Weak Equivalence Principle is scheduled for 2012/2013. The free fall accelerometer test campaign at ZARM is an important part of the pre-mission test program. In this presentation the free flyer technology, its performance as well as the accelerometer tests are described.

  14. Analysis and testing of a new method for drop size measurement using laser scatter interferometry

    NASA Technical Reports Server (NTRS)

    Bachalo, W. D.; Houser, M. J.

    1984-01-01

    Research was conducted on a laser light scatter detection method for measuring the size and velocity of spherical particles. The method is based upon the measurement of the interference fringe pattern produced by spheres passing through the intersection of two laser beams. A theoretical analysis of the method was carried out using the geometrical optics theory. Experimental verification of the theory was obtained by using monodisperse droplet streams. Several optical configurations were tested to identify all of the parametric effects upon the size measurements. Both off-axis forward and backscatter light detection were utilized. Simulated spray environments and fuel spray nozzles were used in the evaluation of the method. The measurements of the monodisperse drops showed complete agreement with the theoretical predictions. The method was demonstrated to be independent of the beam intensity and extinction resulting from the surrounding drops. Signal processing concepts were considered and a method was selected for development.

  15. Drop and Flight Tests on NY-2 Landing Gears Including Measurements of Vertical Velocities at Landing

    NASA Technical Reports Server (NTRS)

    Peck, W D; Beard, A P

    1933-01-01

    This investigation was conducted to obtain quantitative information on the effectiveness of three landing gears for the NY-2 (consolidated training) airplane. The investigation consisted of static, drop, and flight tests on landing gears of the oleo-rubber-disk and the mercury rubber-chord types, and flight tests only on a landing gear of the conventional split-axle rubber-cord type. The results show that the oleo gear is the most effective of the three landing gears in minimizing impact forces and in dissipating the energy taken.

  16. Quasi-Uniform High Speed Foam Crush Testing Using a Guided Drop Mass Impact

    NASA Technical Reports Server (NTRS)

    Jones, Lisa E. (Technical Monitor); Kellas, Sotiris

    2004-01-01

    A relatively simple method for measuring the dynamic crush response of foam materials at various loading rates is described. The method utilizes a drop mass impact configuration with mass and impact velocity selected such that the crush speed remains approximately uniform during the entire sample crushing event. Instrumentation, data acquisition, and data processing techniques are presented, and limitations of the test method are discussed. The objective of the test method is to produce input data for dynamic finite element modeling involving crash and energy absorption characteristics of foam materials.

  17. Cost effectiveness of introducing a new European evaporative emissions test procedure for petrol vehicles

    NASA Astrophysics Data System (ADS)

    Haq, Gary; Martini, Giorgio; Mellios, Giorgos

    2014-10-01

    Evaporative emissions of non-methane volatile organic compounds (NMVOCs) arise from the vehicle's fuel system due to changes in ambient and vehicle temperatures, and contribute to urban smog. This paper presents an economic analysis of the societal costs and benefits of implementing a revised European evaporative emission test procedure for petrol vehicles under four scenarios for the period 2015-2040. The paper concludes that the most cost-effective option is the implementation of an aggressive purging strategy over 48 h and improved canister durability (scenario 2+). The average net benefit of implementing this scenario is €146,709,441 at a 6% discount rate. Per vehicle benefits range from €6-9 but when fuel savings benefits are added, total benefits range from €13-18. This is compared to average additional cost per vehicle of €9.

  18. The influence of the equivalent hydraulic diameter on the pressure drop prediction of annular test section

    NASA Astrophysics Data System (ADS)

    Al-Kayiem, A. H. H.; Ibrahim, M. A.

    2015-12-01

    The flow behaviour and the pressure drop throughout an annular flow test section was investigated in order to evaluate and justify the reliability of experimental flow loop for wax deposition studies. The specific objective of the present paper is to assess and highlight the influence of the equivalent diameter method on the analysis of the hydrodynamic behaviour of the flow and the pressure drop throughout the annular test section. The test section has annular shape of 3 m length with three flow passages, namely; outer thermal control jacket, oil annular flow and inner pipe flow of a coolant. The oil annular flow has internal and external diameters of 0.0422 m and 0.0801 m, respectively. Oil was re-circulated in the annular passage while a cold water-glycol mixture was re-circulated in the inner pipe counter currently to the oil flow. The experiments were carried out at oil Reynolds number range of 2000 to 17000, covering laminar, transition and turbulent flow regimes. Four different methods of equivalent diameter of the annulus have been considered in this hydraulic analysis. The correction factor model for frictional pressure drop was also considered in the investigations. All methods addressed the high deviation of the prediction from the experimental data, which justified the need of a suitable pressure prediction correlation for the annular test section. The conventional hydraulic diameter method is a convenient substitute for characterizing physical dimension of a non-circular duct, and it leads to fairly good correlation between turbulent fluid flow and heat transfer characteristic of annular ducts.

  19. The genotoxicity study of garlic and pasipy herbal drops by peripheral blood micronucleus test.

    PubMed

    Kalantari, H; Larki, A; Latifi, S M

    2007-09-01

    The in vivo rodent micronucleus test is widely used as a genotoxic assay to detect the clastogenic activity of chemicals. In this research the genotoxic effects of herbal drops of garlic and pasipy were evaluated using the micronucleus test. Maximum Tolerated Dose (MTD) was determined by a dose-response test. For each medicine three treatment groups were considered with doses of MTD, 1/2 MTD and 1/4 MTD according to the CSGMT protocol (1995 Japan). Drugs were administered orally to mice (test groups). Mitomicin C was used as a known genotoxic agent in positive control group. The peripheral blood samples before treatment (zero time samples) were considered as negative control. The appearance of a micronucleus is used as an index for genotoxic potential. The results obtained indicated that the herbal drops showed genotoxicity effect and it was dose-dependent compared to the negative control group. This genotoxicity was significant (p < 0.05) but the genotoxic effects of garlic and pasipy were "not significant" compared to the historical negative control group (p > 0.05). Therefore our results if compared to the negative control group is significant and it is worthy of consideration. PMID:17853777

  20. Fundamental limitations to high-precision tests of the universality of free fall by dropping atoms

    NASA Astrophysics Data System (ADS)

    Nobili, Anna M.

    2016-02-01

    Tests of the universality of free fall and the weak equivalence principle probe the foundations of general relativity. Evidence of a violation may lead to the discovery of a new force. The best torsion balance experiments have ruled it out to 10-13. Cold-atom drop tests have reached 10-7 and promise to do 7 to 10 orders of magnitude better, on the ground or in space. They are limited by the random shot noise, which depends on the number N of atoms in the clouds (as 1 /√{N } ). As mass-dropping experiments in the nonuniform gravitational field of Earth, they are sensitive to the initial conditions. Random accelerations due to initial condition errors of the clouds are designed to be at the same level as shot noise, so that they can be reduced with the number of drops along with it. This sets the requirements for the initial position and velocity spreads of the clouds with given N . In the STE-QUEST space mission proposal aiming at 2 ×10-15 they must be about a factor 8 above the limit established by Heisenberg's uncertainty principle, and the integration time required to reduce both errors is 3 years, with a mission duration of 5 years. Instead, offset errors at release between position and velocity of different atom clouds are systematic and give rise to a systematic effect which mimics a violation. Such systematic offsets must be demonstrated to be as small as required in all drops, i.e., they must be kept small by design, and they must be measured. For STE-QUEST to meet its goal they must be several orders of magnitude smaller than the size—in position and velocity space—of each individual cloud, which in its turn must be at most 8 times larger than the uncertainty principle limit. Even if all technical problems are solved and different atom clouds are released with negligible systematic errors, still these errors must be measured; and Heisenberg's principle dictates that such measurement lasts as long as the experiment. While shot noise is random, hence

  1. Syracuse Univesity Test Report On Uptake Factor Resulting From A Dropped Storage Container - Phase II

    SciTech Connect

    Gao, Zhi; Zhang, Jianshun S.

    2012-01-01

    Under certain circumstances, powder from an accidently dropped container can become airborne and inhaled by people nearby such as those who are moving the containers. The inhaled fine particles can deposit on respiratory tracts and lungs, causing asthma, lung cancer, and other acute respiratory illnesses and chronic symptoms. The objective of this study was to develop a standard procedure to measure the airborne concentrations of different size particles within the vicinity of a dropped container where a significant portion of the contained powder is ejected. Tungsten oxide (WO{sub 3}) was selected in this study to represent relatively heavy powders (7.16 g/cm3 specific gravity for WO{sub 3}). A typical can with the outer dimensions of 4.25” diameter and 4.875” tall was used as the container. The powder was dropped in two different configurations: 1) contained within a can covered by a lid that has a 0.25” diameter hole, and 2) contained within a can without a lid. The packing volume of the powder was 51.4 in3 (842.7 cm{sup 3}) and the target mass was 1936 g. The tests were carried out in a full-scale stainless steel environmental chamber with an interior volume of 852 ft3 (24.1 m3). The chamber system includes an internal recirculation loop with a rectangular air diffuser and 10 variable frequency drive fans to provide a typical room air recirculation flow pattern. Two air filters were installed in the chamber air supply duct and return duct to achieve the required low background particle concentration. The initial chamber air conditions were set at 70°F (± 5°F) and 50% (± 10%) RH. A supporting frame and releasing device were designed and built to trigger consistently the dropping of the can. The particle sampling inlet was placed 5 ft above the floor and 6 inches laterally away from the can’s falling path. Concentrations of particles between 0.5 μm and 20 μm were recorded in units of mass and number of particles per unit volume. The data acquisition

  2. Hypothetical accident conditions, free drop and thermal tests: Specification 6M

    SciTech Connect

    Blankenship, R.W.

    1980-05-01

    The 30 gallon Specification 6M shipping container with rolled-top food pack cans as inner containers is evaluated under conditions required by 10 CFR 71.42. One kilogram of depleted uranium as UO/sub 2/ was packaged in each of the inner containers. After completion of a free drop test and a simulated thermal test, the maximum observed leakage of UO/sub 2/ for the following week was 3.2 ..mu..g. This leakage is well below the allowable leakage per week for most plutonium isotopic mixtures. Using the examples provided, any plutonium isotopic mixture can be easily compared with the allowable leakage per week. Test conditions and results are reported.

  3. Vertical drop test of a transport fuselage section located aft of the wing

    NASA Technical Reports Server (NTRS)

    Fasanella, E. L.; Alfaro-Bou, E.

    1986-01-01

    A 12-foot long Boeing 707 aft fuselage section with a tapering cross section was drop tested at the NASA Langley Research Center to measure structural, seat, and occupant response to vertical crash laods and to provide data for nonlinear finite element modeling. This was the final test in a series of three different transport fuselage sections tested under identical conditions. The test parameters at impact were: 20 ft/s velocity, and zero pitch, roll, and yaw. In addition, the test was an operational shock test of the data acquisition system used for the Controlled Impact Demonstration (CID) of a remotely piloted Boeing 720 that was crash tested at NASA Ames Dryden Flight Research Facility on December 1, 1984. Post-test measurements of the crush showed that the front of the section (with larger diameter) crushed vertically approximately 14 inches while the rear crushed 18 inches. Analysis of the data traces indicate the maximum peak normal (vertical) accelerations at the bottom of the frames were approximately 109 G at body station 1040 and 64 G at body station 1120. The peak floor acceleration varied from 14 G near the wall to 25 G near the center where high frequency oscillations of the floor were evident. The peak anthropomorphic dummy pelvis normal (vertical) acceleration was 19 G's.

  4. Evaporation Basin Test Reactor Area, Idaho National Engineering Laboratory: Environmental assessment

    SciTech Connect

    Not Available

    1991-12-01

    The Department of Energy (DOE) has prepared an environmental assessment (EA), DOE/EA-0501, on the construction and operation of the proposed Evaporation Basin at the Test Reactor Area (TRA) at the Idaho National Engineering Laboratory (INEL) near Idaho Falls, Idaho. Based on the analyses in the EA, DOE has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, the preparation of an environmental impact statement (EIS) is not required, and the Department is issuing this Finding of No Significant Impact.

  5. Testing of Commercial Hollow Fiber Membranes for Space Suit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Trevino, Luis; Tsioulos, Gus; Hanford, Anthony

    2009-01-01

    Three commercial-off-the-shelf (COTS) hollow fiber (HoFi) membrane evaporators, modified for low pressure, were tested in a vacuum chamber at pressures below 33 pascals as potential space suit water membrane evaporator (SWME) heat rejection technologies. Water quality was controlled in a series of 25 tests, first simulating potable water reclaimed from waste water and then changing periodically to simulate the ever concentrating make-up of the circulating coolant over that is predicted over the course of 100 EVAs. Two of the systems, comprised of non-porous tubes with hydrophilic molecular channels as the water vapor transport mechanism, were severely impacted by the increasing concentrations of cations in the water. One of the systems, based on hydrophobic porous polypropylene tubes was not affected by the degrading water quality, or the presence of microbes. The polypropylene system, called SWME 1, was selected for further testing. An inverse flow configuration was also tested with SWME 1, with vacuum exposure on the inside of the tubes, provided only 20% of the performance of the standard configuration. SWME 1 was also modified to block 50% and 90% of the central tube layers, and tested to investigate performance efficiency. Performance curves were also developed in back-pressure regulation tests, and revealed important design considerations arising from the fully closed valve. SWME 1 was shown to be insensitive to air bubbles injected into the coolant loop. Development and testing of a full-scale prototype based on this technology and these test results is in progress.

  6. Vertical Drop Testing and Analysis of the WASP Helicopter Skid Gear

    NASA Technical Reports Server (NTRS)

    Fuchs, Yvonne T.; Jackson, Karen E.

    2008-01-01

    Human occupant modeling and injury risk assessment have been identified as areas of research for improved prediction of rotorcraft crashworthiness within the NASA Aeronautics Program's Subsonic Rotary Wing Project. As part of this effort, an experimental program was conducted to assess the impact performance of a skid gear for use on the WASP kit-built helicopter, which is marketed by HeloWerks, Inc. of Hampton, Virginia. Test data from a drop test at an impact velocity of 8.4 feet-per-second were used to assess a finite element model of the skid gear test article. This assessment included human occupant analytic models developed for execution in LS-DYNA. The test article consisted of an aluminum skid gear mounted beneath a steel plate. A seating platform was attached to the upper surface of the steel plate, and two 95th percentile Hybrid III male Aerospace Anthropomorphic Test Devices (ATDs) were seated on the platform and secured using a four-point restraint system. The goal of the test-analysis correlation is to further the understanding of LS-DYNA ATD occupant models and responses in the vertical (or spinal) direction. By correlating human occupant experimental test data for a purely vertical impact with the LS-DYNA occupant responses, improved confidence in the use of these tools and better understanding of the limitations of the automotive-based occupant models for aerospace application can begin to be developed.

  7. Vertical Drop Testing and Analysis of the WASP Helicopter Skid Gear

    NASA Technical Reports Server (NTRS)

    Fuchs, Yvonne T.; Jackson, Karen E.

    2008-01-01

    Human occupant modeling and injury risk assessment have been identified as areas of research for improved prediction of rotorcraft crashworthiness within the NASA Aeronautics Program s Subsonic Rotary Wing Project. As part of this effort, an experimental program was conducted to assess the impact performance of a skid gear for use on the WASP kit-built helicopter, which is marketed by HeloWerks, Inc. of Hampton, Virginia. Test data from a drop test at an impact velocity of 8.4 feet-per-second were used to assess a finite element model of the skid gear test article. This assessment included human occupant analytic models developed for execution in LS-DYNA. The test article consisted of an aluminum skid gear mounted beneath a steel plate. A seating platform was attached to the upper surface of the steel plate, and two 95th percentile Hybrid III male Aerospace Anthropomorphic Test Devices (ATDs) were seated on the platform and secured using a four-point restraint system. The goal of the test-analysis correlation is to further the understanding of LS-DYNA ATD occupant models and responses in the vertical (or spinal) direction. By correlating human occupant experimental test data for a purely vertical impact with the LS-DYNA occupant responses, improved confidence in the use of these tools and better understanding of the limitations of the automotive-based occupant models for aerospace application can begin to be developed.

  8. Full-Scale Hollow Fiber Spacesuit Water Membrane Evaporator Prototype Development and Testing for Advanced Spacesuits

    NASA Technical Reports Server (NTRS)

    Bue, Grant; Trevino, Luis; Tsioulos, Gus; Mitchell, Keith; Dillon, Paul; Weaver, Gregg

    2009-01-01

    The spacesuit water membrane evaporator (SWME) is being developed to perform the thermal control function for advanced spacesuits to take advantage of recent advances in micropore membrane technology in providing a robust heat-rejection device that is potentially less sensitive to contamination than is the sublimator. Principles of a sheet membrane SWME design were demonstrated using a prototypic test article that was tested in a vacuum chamber at JSC in July 1999. The Membrana Celgard X50-215 microporous hollow fiber (HoFi) membrane was selected after recent contamination tests as the superior candidate among commercial alternatives for HoFi SWME prototype development. Although a number of design variants were considered, one that grouped the fiber layers into stacks, which were separated by small spaces and packaged into a cylindrical shape, was deemed best for further development. An analysis of test data showed that eight layer stacks of the HoFi sheets that had good exposure on each side of the stack would evaporate water with high efficiency. A design that has 15,000 tubes, with 18 cm of exposed tubes between headers has been built and tested that meets the size, weight, and performance requirements of the SWME. This full-scale prototype consists of 30 stacks, each of which are formed into a chevron shape and separated by spacers and organized into three sectors of ten nested stacks. Testing has been performed to show contamination resistance to the constituents expected to be found in potable water produced by the distillation processes. Other tests showed the sensitivity to surfactants.

  9. Hollow Fiber Spacesuit Water Membrane Evaporator Development and Testing for Advanced Spacesuits

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Trevino, Luis; Tsioulos, Gus; Settles, Joseph; Colunga, Aaron; Vogel, Matthew; Vonau, Walt

    2010-01-01

    Grant Bue and Matthew Vogel presented the two types of Spacesuit Water Membrane Evaporators (SWME) that were developed based on hydrophobic microporous membranes. One type, the Sheet Membrane (SaM) SWME, is composed of six concentric Teflon sheet membranes fixed on cylindrical-supporting screens to form three concentric annular water channels. Those water channels are surrounded by vacuum passages to draw off the water vapor that passes through the membrane. The other type, the Hollow Fiber (HoFi) SWME, is composed of more than 14,000 tubes. Water flows through the tubes and water vapor passes through the tube wall to the shell side that vents to the vacuum of space. Both SWME types have undergone testing to baseline the performance at predicted operating temperatures and flow rates; the units also have been subjected to contamination testing and other conditions to test resiliency.

  10. Evaporative cooling: effective latent heat of evaporation in relation to evaporation distance from the skin.

    PubMed

    Havenith, George; Bröde, Peter; den Hartog, Emiel; Kuklane, Kalev; Holmer, Ingvar; Rossi, Rene M; Richards, Mark; Farnworth, Brian; Wang, Xiaoxin

    2013-03-15

    Calculation of evaporative heat loss is essential to heat balance calculations. Despite recognition that the value for latent heat of evaporation, used in these calculations, may not always reflect the real cooling benefit to the body, only limited quantitative data on this is available, which has found little use in recent literature. In this experiment a thermal manikin, (MTNW, Seattle, WA) was used to determine the effective cooling power of moisture evaporation. The manikin measures both heat loss and mass loss independently, allowing a direct calculation of an effective latent heat of evaporation (λeff). The location of the evaporation was varied: from the skin or from the underwear or from the outerwear. Outerwear of different permeabilities was used, and different numbers of layers were used. Tests took place in 20°C, 0.5 m/s at different humidities and were performed both dry and with a wet layer, allowing the breakdown of heat loss in dry and evaporative components. For evaporation from the skin, λeff is close to the theoretical value (2,430 J/g) but starts to drop when more clothing is worn, e.g., by 11% for underwear and permeable coverall. When evaporation is from the underwear, λeff reduction is 28% wearing a permeable outer. When evaporation is from the outermost layer only, the reduction exceeds 62% (no base layer), increasing toward 80% with more layers between skin and wet outerwear. In semi- and impermeable outerwear, the added effect of condensation in the clothing opposes this effect. A general formula for the calculation of λeff was developed. PMID:23329814

  11. Numerical simulation and field test study of desulfurization wastewater evaporation treatment through flue gas.

    PubMed

    Deng, Jia-Jia; Pan, Liang-Ming; Chen, De-Qi; Dong, Yu-Quan; Wang, Cheng-Mu; Liu, Hang; Kang, Mei-Qiang

    2014-01-01

    Aimed at cost saving and pollution reduction, a novel desulfurization wastewater evaporation treatment system (DWETS) for handling wet flue gas desulfurization (WFGD) wastewater of a coal-fired power plant was studied. The system's advantages include simple process, and less investment and space. The feasibility of this system has been proven and the appropriate position and number of nozzles, the spray droplet size and flue gas temperature limitation have been obtained by computational fluid dynamics (CFD) simulation. The simulation results show that a longer duct, smaller diameter and higher flue gas temperature could help to increase the evaporation rate. The optimal DWETS design of Shangdu plant is 100 μm droplet sprayed by two nozzles located at the long duct when the flue gas temperature is 130 °C. Field tests were carried out based on the simulation results. The effects of running DWETS on the downstream devices have been studied. The results show that DWETS has a positive impact on ash removal efficiency and does not have any negative impact on the electrostatic precipitator (ESP), flue gas heat exchanger and WFGD. The pH values of the slurry of WFGD slightly increase when the DWETS is running. The simulation and field test of the DWETS show that it is a feasible future technology for desulfurization wastewater treatment. PMID:25325555

  12. Test-Analysis Correlation of a Crash Simulation of a Vertical Drop Test of a Commuter-Category Aircraft

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.

    2004-01-01

    A finite element model of an ATR42-300 commuter-class aircraft was developed and a crash simulation was executed. Analytical predictions were correlated with data obtained from a 30-feet per second (9.14-meters per second) vertical drop test of the aircraft. The purpose of the test was to evaluate the structural response of the aircraft when subjected to a severe, but survivable, impact. The aircraft was configured with seats, dummies, luggage, and other ballast. The wings were filled with 8,700 lb. (3,946 kilograms) of water to represent the fuel. The finite element model, which consisted of 57,643 nodes and 62,979 elements, was developed from direct measurements of the airframe geometry. The seats, dummies, luggage, simulated engines and fuel, and other ballast were represented using concentrated masses. The model was executed in LS-DYNA, a commercial finite element code for performing explicit transient dynamic simulations. Analytical predictions of structural deformation and selected time-history responses were correlated with experimental data from the drop test to validate the simulation.

  13. Analytical Evaluation of Preliminary Drop Tests Performed to Develop a Robust Design for the Standardized DOE Spent Nuclear Fuel Canister

    SciTech Connect

    A.G. Ware; D.K. Morton; N.L. Smith; S.D. Snow; T.E. Rahl

    1999-08-01

    The Department of Energy (DOE) has developed a design concept for a set of standard canisters for the handling, interim storage, transportation, and disposal in the national repository, of DOE spent nuclear fuel (SNF). The standardized DOE SNF canister has to be capable of handling virtually all of the DOE SNF in a variety of potential storage and transportation systems. It must also be acceptable to the repository, based on current and anticipated future requirements. This expected usage mandates a robust design. The canister design has four unique geometries, with lengths of approximately 10 feet or 15 feet, and an outside nominal diameter of 18 inches or 24 inches. The canister has been developed to withstand a drop from 30 feet onto a rigid (flat) surface, sustaining only minor damage - but no rupture - to the pressure (containment) boundary. The majority of the end drop-induced damage is confined to the skirt and lifting/stiffening ring components, which can be removed if de sired after an accidental drop. A canister, with its skirt and stiffening ring removed after an accidental drop, can continue to be used in service with appropriate operational steps being taken. Features of the design concept have been proven through drop testing and finite element analyses of smaller test specimens. Finite element analyses also validated the canister design for drops onto a rigid (flat) surface for a variety of canister orientations at impact, from vertical to 45 degrees off vertical. Actual 30-foot drop testing has also been performed to verify the final design, though limited to just two full-scale test canister drops. In each case, the analytical models accurately predicted the canister response.

  14. Characterization of new eye drops with choline salicylate and assessment of their irritancy by in vitro short time exposure tests.

    PubMed

    Wroblewska, Katarzyna; Kucinska, Małgorzata; Murias, Marek; Lulek, Janina

    2015-09-01

    The aim of our study was to examine the irritation potential of new eye drops containing 2% choline salicylate (CS) as an active pharmaceutical ingredient (API) and various polymers increasing eye drop viscosity (hydroxyethylcellulose, hydroxypropyl methylcellulose, methylcellulose, polyvinyl alcohol, polyvinylpyrrolidone). The standard method for assessing the potential of irritating substances has been the Draize rabbit eye test. However the European Centre for Validation of Alternative Methods and the Coordinating Committee for Validation of Alternative Methods recommend, short time exposure (STE) in vitro tests as an alternative method for assessing eye irritation. The eye irritation potential was determined using cytotoxicity test methods for rabbit corneal cell line (SIRC) after 5 min exposure. The viability of cells was determined using two cytotoxicity assays: MTT and Neutral Red Uptake. According to the irritation rankings for the short time exposure test, all tested eye drops are classified as non-irritating (cell viability >70%). PMID:27134543

  15. Characterization of new eye drops with choline salicylate and assessment of their irritancy by in vitro short time exposure tests

    PubMed Central

    Wroblewska, Katarzyna; Kucinska, Małgorzata; Murias, Marek; Lulek, Janina

    2014-01-01

    The aim of our study was to examine the irritation potential of new eye drops containing 2% choline salicylate (CS) as an active pharmaceutical ingredient (API) and various polymers increasing eye drop viscosity (hydroxyethylcellulose, hydroxypropyl methylcellulose, methylcellulose, polyvinyl alcohol, polyvinylpyrrolidone). The standard method for assessing the potential of irritating substances has been the Draize rabbit eye test. However the European Centre for Validation of Alternative Methods and the Coordinating Committee for Validation of Alternative Methods recommend, short time exposure (STE) in vitro tests as an alternative method for assessing eye irritation. The eye irritation potential was determined using cytotoxicity test methods for rabbit corneal cell line (SIRC) after 5 min exposure. The viability of cells was determined using two cytotoxicity assays: MTT and Neutral Red Uptake. According to the irritation rankings for the short time exposure test, all tested eye drops are classified as non-irritating (cell viability >70%). PMID:27134543

  16. Thermal Vacuum Testing of a Multi-Evaporator Miniature Loop Heat Pipe

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Ottenstein, Laura; Nagano, Hosei

    2008-01-01

    Under NASA's New Millennium Program Space Technology 8 Project, four experiments are being developed for future small system applications requiring low mass, low power, and compactness. GSFC is responsible for developing the Thermal Loop experiment, which is an advanced thermal control system consisting of a miniature loop heat pipe (MLHP) with multiple evaporators and condensers. The objective is to validate the operation of an MLHP, including reliable start-ups, steady operation, heat load sharing, and tight temperature control over the range of 273K to 308K. An MLHP Breadboard has been built and tested for 1200 hours under the laboratory environment and 500 hours in a thermal vacuum chamber. Results of the TV tests are presented here.

  17. Hollow Fiber Flight Prototype Spacesuit Water Membrane Evaporator Design and Testing

    NASA Technical Reports Server (NTRS)

    Bue, Grant; Vogel, Matt; Makinen, Janice; Tsioulos, Gus

    2010-01-01

    The spacesuit water membrane evaporator (SWME) is being developed to perform thermal control for advanced spacesuits and to take advantage of recent advances in micropore membrane technology. This results in a robust heat-rejection device that is potentially less sensitive to contamination than is the sublimator. The Membrana Celgard X50-215 microporous hollow-fiber (HoFi) membrane was selected after recent extensive testing as the most suitable candidate among commercial alternatives for continued SWME prototype development. The current design was based on a previous design that grouped the fiber layers into stacks, which were separated by small spaces and packaged into a cylindrical shape. This was developed into a full-scale prototype consisting of 14,300 tube bundled into 30 stacks, each of which is formed into a chevron shape and separated by spacers and organized into three sectors of 10 nested stacks. The new design replaced metal components with plastic ones, and has a custom built flight like backpressure valve mounted on the side of the SWME housing to reduce backpressure when fully open. The spacers that provided separation of the chevron fiber stacks were eliminated. Vacuum chamber testing showed improved heat rejection as a function of inlet water temperature and water vapor backpressure compared with the previous design. Other tests pushed the limits of tolerance to freezing and showed suitability to reject heat in a Mars pressure environment with and without a sweep gas. Tolerance to contamination by constituents expected to be found in potable water produced by distillation processes was tested in a conventional way by allowing constituents to accumulate in the coolant as evaporation occurs. For this purpose, the SWME cartridge has endured an equivalent of 30 EVAs exposure and demonstrated minimal performance decline.

  18. Hollow Fiber Space Water Membrane Evaporator Flight Prototype Design and Testing

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Makinen, Janice; Vogel, Mtthew; Honas, Matt; Dillon, Paul; Colunga, Aaron; Truong, Lily; Porwitz, Darwin; Tsioulos, Gus

    2011-01-01

    The spacesuit water membrane evaporator (SWME) is being developed to perform thermal control for advanced spacesuits and to take advantage of recent advances in micropore membrane technology. This results in a robust heat-rejection device that is potentially less sensitive to contamination than is the sublimator. The current design was based on a previous design that grouped the fiber layers into stacks, which were separated by small spaces and packaged into a cylindrical shape. This was developed into a full-scale prototype consisting of 14,300 tube bundled into 30 stacks, each of which is formed into a chevron shape and separated by spacers and organized into three sectors of 10 nested stacks. The new design replaced metal components with plastic ones, eliminated the spacers, and has a custom built flight like backpressure valve mounted on the side of the SWME housing to reduce backpressure when fully open. A number of tests were performed in order to improve the strength of the polyurethane header that holds the fibers in place while the system is pressurized. Vacuum chamber testing showed similar heat rejection as a function of inlet water temperature and water vapor backpressure was similar to the previous design. Other tests pushed the limits of tolerance to freezing and showed suitability to reject heat in a Mars pressure environment with and without a sweep gas. Tolerance to contamination by constituents expected to be found in potable water produced by distillation processes was tested in a conventional way by allowing constituents to accumulate in the coolant as evaporation occurs. For this purpose, the SWME cartridge has endured an equivalent of 30 EVAs exposure and demonstrated acceptable performance decline.

  19. Crash Simulation of a Vertical Drop Test of a Commuter-Class Aircraft

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.

    2004-01-01

    A finite element model of an ATR42-300 commuter-class aircraft was developed and a crash simulation was executed. Analytical predictions were correlated with data obtained from a 30-ft/s (9.14-m/s) vertical drop test of the aircraft. The purpose of the test was to evaluate the structural response of the aircraft when subjected to a severe, but survivable, impact. The aircraft was configured with seats, dummies, luggage, and other ballast. The wings were filled with 8,700 lb. (3,946 kg) of water to represent the fuel. The finite element model, which consisted of 57,643 nodes and 62,979 elements, was developed from direct measurements of the airframe geometry. The seats, dummies, luggage, fuel, and other ballast were represented using concentrated masses. The model was executed in LS-DYNA, a commercial code for performing explicit transient dynamic simulations. Predictions of structural deformation and selected time-history responses were generated. The simulation was successfully validated through extensive test-analysis correlation.

  20. Hollow Fiber Spacesuit Water Membrane Evaporator Development and Testing for Advanced Spacesuits

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Trevino, Luis A.; Tsioulos, Gus; Settles, Joseph; Colunga, Aaron; Vogel, Matthew; Vonau, Walt

    2010-01-01

    The spacesuit water membrane evaporator (SWME) is being developed to perform the thermal control function for advanced spacesuits to take advantage of recent advances in micropore membrane technology in providing a robust heat-rejection device that is potentially less sensitive to contamination than is the sublimator. Principles of a sheet membrane SWME design were demonstrated using a prototypic test article that was tested in a vacuum chamber at JSC in July 1999. The Membrana Celgard X50-215 microporous hollow fiber (HoFi) membrane was selected after recent contamination tests as the most suitable candidate among commercial alternatives for HoFi SWME prototype development. A design that grouped the fiber layers into stacks, which were separated by small spaces and packaged into a cylindrical shape, was developed into a full-scale prototype consisting 14,300 tube bundled into 30 stacks, each of which are formed into a chevron shape and separated by spacers and organized into three sectors of ten nested stacks. Vacuum chamber testing has been performed characterize heat rejection as a function of inlet water temperature and water vapor backpressure and to show contamination resistance to the constituents expected to be found in potable water produced by the distillation processes. Other tests showed the tolerance to freezing and suitability to reject heat in a Mars pressure environment.

  1. Predicting the Drop Performance of Solder Joints by Evaluating the Elastic Strain Energy from High-Speed Ball Pull Tests

    NASA Astrophysics Data System (ADS)

    You, Taehoon; Kim, Yunsung; Kim, Jina; Lee, Jaehong; Jung, Byungwook; Moon, Jungtak; Choe, Heeman

    2009-03-01

    Despite being expensive and time consuming, board-level drop testing has been widely used to assess the drop or impact resistance of the solder joints in handheld microelectronic devices, such as cellphones and personal digital assistants (PDAs). In this study, a new test method, which is much simpler and quicker, is proposed. The method involves evaluating the elastic strain energy and relating it to the impact resistance of the solder joint by considering the Young’s modulus of the bulk solder and the fracture stress of the solder joint during a ball pull test at high strain rates. The results show that solder joints can be ranked in order of descending elastic strain energy as follows: Sn-37Pb, Sn-1Ag-0.5Cu, Sn-3Ag-0.5Cu, and Sn-4Ag-0.5Cu. This order is consistent with the actual drop performances of the samples.

  2. Comparison of drop size data from ground and aerial application nozzles at three testing laboratories

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spray drop size is a critical factor in the performance of any agrochemical solution and is a function of spray solution, nozzle selection, and nozzle operation. Applicators generally base their selection of a particular nozzle based on the drop size reported by manufacturers and researchers. Like m...

  3. Drop Tower tests in preparation of a Tethered Electromagnetic Docking space demonstration

    NASA Astrophysics Data System (ADS)

    Olivieri, Lorenzo; Francesconi, Alessandro; Antonello, Andrea; Bettiol, Laura; Branz, Francesco; Duzzi, Matteo; Mantellato, Riccardo; Sansone, Francesco; Savioli, Livia

    2016-07-01

    A group of students of the University of Padova is recently developing some technologies to implement a Tethered Electromagnetic Docking (TED) experiment, a novel system for close rendezvous and mating manoeuvres between two spacecraft, consisting in a small tethered probe ejected by the chaser and magnetically guided by a receiving electromagnet mounted on the target. Because of the generated magnetic field, automatic self-alignment and mating are possible; then, as the tether is rewinded, the chaser is able to dock with the target. This concept allows to simplify standard docking procedures, thanks to the reduction of proximity navigation and guidance requirements, as well as consequent fuel reduction. Other interesting applications are expected, from active debris removal to space tugging; in particular, the utilization of the tethered connection for detumbling operations is considered. The realization of a space demonstrator requires a preliminary verification of the critical technologies employed in TED, in particular the magnetic guidance and the probe deploy and retrieve; in the framework of ESA "Drop your Thesis!" 2014 and 2016 campaigns the experiments FELDs (Flexible Electromagnetic Leash Docking system) and STAR (System for Tether Automatic Retrieval) have been focused on the test of such critical elements in the relevant microgravity environment of ZARM Drop Tower in Bremen. In particular, FELDs consisted in a simplified model of TED with a magnetic target interface, a passive tethered probe and its launch system: the experiment allowed to assess the passive self-alignment of the probe with respect to the target and to study the effect of friction between the tether and the release system. Similarly, STAR is investigating the tether actively controlled deployment and retrieval, with the experiment campaign planned on November 2016. In addition, another microgravity experiment is in preparation for the investigation of active magnetic navigation: PACMAN

  4. Evaporative emissions in three-day diurnal breathing loss tests on passenger cars for the Japanese market

    NASA Astrophysics Data System (ADS)

    Yamada, Hiroyuki; Inomata, Satoshi; Tanimoto, Hiroshi

    2015-04-01

    Breakthrough emissions that dominate diurnal evaporative emissions from gasoline vehicles were observed in continuous 3-day diurnal breathing loss (DBL) tests. These measurements were conducted on nine vehicles for the Japanese market. Two of these vehicles, made by US and European manufacturers, also meet regulations in their countries of origin. Four vehicles exhibited marked emissions caused by breakthrough emissions during the experimental period, all made by Japanese manufacturers. Using our experimental results, we estimate the total diurnal evaporative emissions from gasoline vehicles in Japan to be 32,792 t y-1. The compositions of the breakthrough and permeation emissions were analyzed in real time using proton transfer reaction plus switchable reagent ion mass spectrometry to estimate the ozone formation potential for the evaporative emissions. The real-time measurements showed that the adsorption of hydrocarbons in a sealed housing evaporative determination unit can result in underestimation, when concentrations are only monitored before and after a DBL test. The composition analysis gave an estimated maximum incremental reactivity (MIR) 20% higher for the breakthrough emissions than for the gasoline that was tested, while the MIR for the permeation emissions was almost the same as the MIR for the fuel. Evaporative emissions from gasoline vehicles in Japan were found to contribute 4.2% to emissions from stationary sources using a mass-based estimate, or 6.1% of emissions from stationary sources using a MIR-based estimate.

  5. Vertical Force-deflection Characteristics of a Pair of 56-inch-diameter Aircraft Tires from Static and Drop Tests with and Without Prerotation

    NASA Technical Reports Server (NTRS)

    Smiley, Robert F; Horne, Walter B

    1957-01-01

    The vertical force-deflection characteristics were experimentally determined for a pair of 56-inch-diameter tires under static and drop-test conditions with and without prerotation. For increasing force, the tires were found to be least stiff for static tests, almost the same as for the static case for prerotation drop tests as long as the tires remain rotating, and appreciably stiffer for drop tests without prerotation.

  6. Design and Certification of Targets for Drop Tests at the NTRC Packaging Research Facility

    SciTech Connect

    Ludwig, S.B.

    2003-06-05

    This report provides documentation of the design and certification of drop pad (targets) at the National Transportation Research Center (NTRC) Packaging Research Facility(PRF). Based on the evaluation performed, it has been demonstrated that the small (interior) drop pad (target) meets the regulatory definition of a flat, essentially unyielding, horizontal surface for packages weighing up to 3,150 lb (1,432 kg). The large (exterior) drop pad (target) meets the regulatory definition of a flat, essentially unyielding, horizontal surface for packages weighing up to 28,184 lb (12,811 kg).

  7. Numerical Investigation of the Influence of Convection in a Mixture of Combustion Products on the Integral Characteristics of the Evaporation of a Finely Atomized Water Drop

    NASA Astrophysics Data System (ADS)

    Kuznetsov, G. V.; Strizhak, P. A.

    2014-01-01

    A model of the heat-and-mass transfer in the neighborhood of a finely atomized water drop moving through the high-temperature products of combustion of materials has been developed for numerical analysis of the macroscopic mechanisms of movement of such a drop in a mixture of combustion products and water vapor with account for the complex of interrelated physical processes and phase transitions taking place in this case. The influence of the convection on the integral characteristics of the evaporation of the indicated drop was analyzed and the sizes of its "temperature" and "concentration" wakes were estimated. The conditions under which the integral characteristics of the evaporation of this drop can be calculated in the diffusion approximation were determined.

  8. Workplace field testing of the pressure drop of particulate respirators using welding fumes.

    PubMed

    Cho, Hyun-Woo; Yoon, Chung-Sik

    2012-10-01

    In a previous study, we concluded that respirator testing with a sodium chloride aerosol gave a conservative estimate of filter penetration for welding fume aerosols. A rapid increase in the pressure drop (PD) of some respirators was observed as fumes accumulated on the filters. The present study evaluated particulate respirator PD based on workplace field tests. A field PD tester was designed and validated using the TSI 8130 Automatic Filter Tester, designed in compliance with National Institute for Occupational and Safety and Health regulation 42 CFR part 84. Three models (two replaceable dual-type filters and one replaceable single-type filter) were evaluated against CO(2) gas arc welding on mild steel in confined booths in the workplace. Field tests were performed under four airborne concentrations (27.5, 15.4, 7.9, and 2.1 mg m(-3)). The mass concentration was measured by the gravimetric method, and number concentration was monitored using P-Trak (Model 8525, TSI, USA). Additionally, photos and scanning electron microscopy-energy dispersive X-ray spectroscopy were used to visualize and analyze the composition of welding fumes trapped in the filters. The field PD tester showed no significant difference compared with the TSI tester. There was no significant difference in the initial PD between laboratory and field results. The PD increased as a function of fume load on the respirator filters for all tested models. The increasing PD trend differed by models, and PD increased rapidly at high concentrations because greater amount of fumes accumulated on the filters in a given time. The increase in PD as a function of fume load on the filters showed a similar pattern as fume load varied for a particular model, but different patterns were observed for different models. Images and elemental analyses of fumes trapped on the respirator filters showed that most welding fumes were trapped within the first layer, outer web cover, and second layer, in order, while no fumes

  9. Drop Hammer Tests with Three Oleo Strut Models and Three Different Shock Strut Oils at Low Temperatures

    NASA Technical Reports Server (NTRS)

    Kranz, M

    1954-01-01

    Drop hammer tests with different shock strut models and shock strut oils were performed at temperatures ranging to -40 C. The various shock strut models do not differ essentially regarding their springing and damping properties at low temperatures; however, the influence of the different shock strut oils on the springing properties at low temperatures varies greatly.

  10. Thermal Vacuum Testing of a Proto-flight Miniature Loop Heat Pipe with Two Evaporators and Two Condensers

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Ottenstein, Laura

    2011-01-01

    This paper describes thermal vacuum testing of a proto-flight miniature loop heat pipe (MLHP) with two evaporators and two condensers designed for future small systems applications requiring low mass, low power and compactness. Each evaporator contains a wick with an outer diameter of 6.35 mm, and each has its own integral compensation chamber (CC). Miniaturization of the loop components reduces the volume and mass of the thermal system. Multiple evaporators provide flexibility for placement of instruments that need to be maintained at the same temperature, and facilitate heat load sharing among instruments, reducing the auxiliary heater power requirement. A flow regulator is used to regulate heat dissipations between the two condensers, allowing flexible placement of radiators on the spacecraft. A thermoelectric converter (TEC) is attached to each CC for control of the operating temperature and enhancement of start-up success. Tests performed include start-up, power cycle, sink temperature cycle, high power and low power operation, heat load sharing, and operating temperature control. The proto-flight MLHP demonstrated excellent performance in the thermal vacuum test. The loop started successfully and operated stably under various evaporator heat loads and condenser sink temperatures. The TECs were able to maintain the loop operating temperature within b1K of the desired set point temperature at all power levels and all sink temperatures. The un-powered evaporator would automatically share heat from the other powered evaporator. The flow regulator was able to regulate the heat dissipation among the radiators and prevent vapor from flowing into the liquid line.

  11. Effect of External Pressure Drop on Loop Heat Pipe Operating Temperature

    NASA Technical Reports Server (NTRS)

    Jentung, Ku; Ottenstein, Laura; Rogers, Paul; Cheung, Kwok; Obenschain, Arthur F. (Technical Monitor)

    2002-01-01

    This paper discusses the effect of the pressure drop on the operating temperature in a loop heat pipe (LHP). Because the evaporator and the compensation chamber (CC) both contain two-phase fluid, a thermodynamic constraint exists between the temperature difference and the pressure drop for these two components. As the pressure drop increases, so will the temperature difference. The temperature difference in turn causes an increase of the heat leak from the evaporator to the CC, resulting in a higher CC temperature. Furthermore, the heat leak strongly depends on the vapor void fraction inside the evaporator core. Tests were conducted by installing a valve on the vapor line so as to vary the pressure drop, and by charging the LHP with various amounts of fluid. Test results verify that the LHP operating temperature increases with an increasing differential pressure, and the temperature increase is a strong function of the fluid inventory in the loop.

  12. FULL SCALE TESTING TECHNOLOGY MATURATION OF A THIN FILM EVAPORATOR FOR HIGH-LEVEL LIQUID WASTE MANAGEMENT AT HANFORD - 12125

    SciTech Connect

    TEDESCHI AR; CORBETT JE; WILSON RA; LARKIN J

    2012-01-26

    Simulant testing of a full-scale thin-film evaporator system was conducted in 2011 for technology development at the Hanford tank farms. Test results met objectives of water removal rate, effluent quality, and operational evaluation. Dilute tank waste simulant, representing a typical double-shell tank supernatant liquid layer, was concentrated from a 1.1 specific gravity to approximately 1.5 using a 4.6 m{sup 2} (50 ft{sup 2}) heated transfer area Rototherm{reg_sign} evaporator from Artisan Industries. The condensed evaporator vapor stream was collected and sampled validating efficient separation of the water. An overall decontamination factor of 1.2E+06 was achieved demonstrating excellent retention of key radioactive species within the concentrated liquid stream. The evaporator system was supported by a modular steam supply, chiller, and control computer systems which would be typically implemented at the tank farms. Operation of these support systems demonstrated successful integration while identifying areas for efficiency improvement. Overall testing effort increased the maturation of this technology to support final deployment design and continued project implementation.

  13. Partitioning evapotranspiration - Testing the Craig and Gordon model with field measurements of oxygen isotope ratios of evaporative fluxes

    NASA Astrophysics Data System (ADS)

    Dubbert, Maren; Cuntz, Matthias; Piayda, Arndt; Maguás, Cristina; Werner, Christiane

    2013-07-01

    Stable oxygen isotopes of water provide a valuable tracer for water movements within ecosystems and are used to estimate the contribution of transpiration to total ecosystem evapotranspiration (ft). We tested the Craig and Gordon equation against continuous field measurements of isotopic composition of evaporation and assessed the impact for partitioning evapotranspiration. Therefore, evaporation (E) and its isotopic signature (δ18OE) on bare soil plots, as well as evapotranspiration (ET) and its corresponding isotopic composition of (δ18OET) of an herbaceous layer was measured with a cavity ring-down spectrometer connected to a soil chamber on a field site in central Portugal. We quantified the variation in δ18OE arising from uncertainties in the determination of environmental input variables to the Craig and Gordon equation: the isotope signature (δ18Oe) and the temperature at the evaporating site (Te), and the kinetic fractionation factor (αk). We could hence quantify ft based on measured δ18OET, modeled δ18OE from observed soil water isotopic composition at the evaporating site (δ18Oe), and modeled δ18O of transpiration (δ18OT) from observed total soil water isotopic composition. Our results demonstrate that predicting δ18OE using the Craig and Gordon equation leads to good agreement with measured δ18OE given that the temperature and 18O isotope profiles of the soil are thoroughly characterized. However, modeled δ18OE is highly sensitive to changes in Te and δ18Oe as well as αk. This markedly affected the partition results of transpiration and evaporation from the total ET flux: The fraction of transpiration (ft) varied strongly using different formulations for αk and assuming steady or non-steady state transpiration. These findings provide a first comparison of laser-based and modeled isotopic compositions of evaporation based on the Craig and Gordon equation under field conditions. This is of special interest for studies using stable isotopes

  14. Sheet Membrane Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Bue, Grant; Trevino, Luis; Zapata, Felipe; Dillion, Paul; Castillo, Juan; Vonau, Walter; Wilkes, Robert; Vogel, Matthew; Frodge, Curtis

    2013-01-01

    A document describes a sheet membrane spacesuit water membrane evaporator (SWME), which allows for the use of one common water tank that can supply cooling water to the astronaut and to the evaporator. Test data showed that heat rejection performance dropped only 6 percent after being subjected to highly contaminated water. It also exhibited robustness with respect to freezing and Martian atmospheric simulation testing. Water was allowed to freeze in the water channels during testing that simulated a water loop failure and vapor backpressure valve failure. Upon closing the backpressure valve and energizing the pump, the ice eventually thawed and water began to flow with no apparent damage to the sheet membrane. The membrane evaporator also serves to de-gas the water loop from entrained gases, thereby eliminating the need for special degassing equipment such as is needed by the current spacesuit system. As water flows through the three annular water channels, water evaporates with the vapor flowing across the hydrophobic, porous sheet membrane to the vacuum side of the membrane. The rate at which water evaporates, and therefore, the rate at which the flowing water is cooled, is a function of the difference between the water saturation pressure on the water side of the membrane, and the pressure on the vacuum side of the membrane. The primary theory is that the hydrophobic sheet membrane retains water, but permits vapor pass-through when the vapor side pressure is less than the water saturation pressure. This results in evaporative cooling of the remaining water.

  15. Foot Drop

    MedlinePlus

    ... Awards Enhancing Diversity Find People About NINDS NINDS Foot Drop Information Page Table of Contents (click to ... research is being done? Clinical Trials What is Foot Drop? Foot drop describes the inability to raise ...

  16. Crash Simulation of a Vertical Drop Test of a B737 Fuselage Section with Overhead Bins and Luggage

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.

    2004-01-01

    The focus of this paper is to describe a crash simulation of a 30-ft/s vertical drop test of a Boeing 737 (B737) fuselage section. The drop test of the 10-ft. long fuselage section of a B737 aircraft was conducted in November of 2000 at the FAA Technical Center in Atlantic City, NJ. The fuselage section was outfitted with two different commercial overhead stowage bins. In addition, 3,229-lbs. of luggage were packed in the cargo hold to represent a maximum take-off weight condition. The main objective of the test was to evaluate the response and failure modes of the overhead stowage bins in a narrow-body transport fuselage section when subjected to a severe, but survivable, impact. A secondary objective of the test was to generate experimental data for correlation with the crash simulation. A full-scale 3-dimensional finite element model of the fuselage section was developed and a crash simulation was conducted using the explicit, nonlinear transient dynamic code, MSC.Dytran. Pre-test predictions of the fuselage and overhead bin responses were generated for correlation with the drop test data. A description of the finite element model and an assessment of the analytical/experimental correlation are presented. In addition, suggestions for modifications to the model to improve correlation are proposed.

  17. Particle-size dependence of immersion freezing: Investigation of INUIT test aerosol particles with freely suspended water drops.

    NASA Astrophysics Data System (ADS)

    Diehl, Karoline; Debertshäuser, Michael; Eppers, Oliver; Jantsch, Evelyn; Mitra, Subir K.

    2014-05-01

    One goal of the research group INUIT (Ice Nuclei research UnIT) is to investigate the efficiencies of several test ice nuclei under comparable conditions but with different experimental techniques. In the present studies, two methods are used: the Mainz vertical wind tunnel and an acoustic levitator placed inside a cold chamber. In both cases drops are freely levitated, either at their terminal velocity in the wind tunnel updraft or around the nodes of a standing ultrasonic wave in the acoustic levitator. Thus, heat transfer conditions are well approximated, and wall contact effects on freezing as well as electrical charges of the drops are avoided. Drop radii are 370 μm and 1 mm, respectively. In the wind tunnel, drops are investigated at constant temperatures within a certain time period and the onset of freezing is observed directly. In the acoustic levitator, the drop temperature decreases during the experiments and is measured by an in-situ calibrated Infrared thermometer. The onset of freezing is indicated by a rapid rise of the drop surface temperature because of the release of latent heat. Investigated test ice nuclei are Snomax® as a proxy of biological particles and illite NX as well as K-feldspar as represents of mineral dust. The particle concentrations are 1 × 10-12 to 3 × 10-6 g Snomax® per drop and 5 × 10-9 to 5 × 10-5 g mineral dust per drop. Freezing temperatures are between -2 and -18° C in case of Snomax® and between -14 and -26° C in case of mineral dust. The lower the particle masses per drop the lower are the freezing temperatures. For similar particle concentrations in the drops, the median freezing temperatures determined by the two techniques agree well within the measurement errors. With the knowledge of the specific particle surface area of the mineral dusts, the results are interpreted also in terms of particle surface area per drop. Results from the wind tunnel experiments which are performed at constant temperatures indicate

  18. The drop-jump video screening test: retention of improvement in neuromuscular control in female volleyball players.

    PubMed

    Barber-Westin, Sue D; Smith, Stephanie T; Campbell, Thomas; Noyes, Frank R

    2010-11-01

    A valgus lower limb alignment is commonly documented during noncontact anterior cruciate ligament injuries. We previously developed a videographic drop-jump test to measure overall lower limb alignment in the coronal plane as a screening tool to detect such an abnormal (valgus) position on landing. A neuromuscular retraining program developed for female athletes was shown to be effective in improving lower limb alignment on this test immediately after completion of training. What remained unknown was whether these improvements would be retained for longer periods of time. Therefore, this study was undertaken to determine if these improvements in overall lower limb alignment would be retained up to 1 year after the training. Sixteen competitive, experienced female high-school volleyball players underwent the video drop-jump test and then completed the neuromuscular retraining program. The program consisted of a dynamic warm-up, jump training, speed and agility drills, strength training, and static stretching and was performed 3 times a week for 6 weeks. The athletes repeated the drop-jump test immediately upon completion of training and then 3- and 12-months later. Significant improvements were found in the mean normalized knee separation distance between the pre and posttrained values for all test sessions (p < 0.01). Immediately after training, 11 athletes (69%) displayed significant improvements in the mean normalized knee separation distance that were retained 12 months later. Five athletes failed to improve. The video drop-jump test, although not a risk indicator for a knee ligament injury, provides a cost-effective general assessment of lower limb position and depicts athletes who have poor control on landing and acceleration into a vertical jump. PMID:20940643

  19. Determining Seed Cotton Mass Flow Rate by Pressure Drop Across a Blowbox: Gin Testing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate measurement of the mass flow rate of seed cotton is needed for control and monitoring purposes in gins. A system was developed that accurately predicted mass flow rate based on the static pressure drop measured across the blowbox and the air velocity and temperature entering the blowbox. Ho...

  20. Design, fabrication, and testing of a sodium evaporator for the STM4-120 kinematic Stirling engine

    NASA Astrophysics Data System (ADS)

    Rawlinson, K. S.; Adkins, D. R.

    1995-05-01

    This report describes the development and testing of a compact heat-pipe heat exchanger kW(e) designed to transfer thermal energy from hot combustion gases to the heater tubes of a 25-kW(e) Stirling engine. In this system, sodium evaporates from a surface that is heated by a stream of hot gases. The liquid metal then condenses on the heater tubes of a Stirling engine, where energy is transferred to the engine's helium working fluid. Tests on a prototype unit illustrated that a compact (8 cm times 13 cm times 16 cm) sodium evaporator can routinely transfer 15 kW(t) of energy at an operating vapor temperature of 760 C. Four of these prototype units were eventually used to power a 25-kW(e) Stirling engine system. Design details and test results from the prototype unit are presented in this report.

  1. Design, fabrication, and testing of a sodium evaporator for the STM4-120 kinematic Stirling engine

    SciTech Connect

    Rawlinson, K.S.; Adkins, D.R.

    1995-05-01

    This report describes the development and testing of a compact heat-pipe heat exchanger kW(e) designed to transfer thermal energy from hot combustion gases to the heater tubes of a 25-kW(e) Stirling engine. In this system, sodium evaporates from a surface that is heated by a stream of hot gases. The liquid metal then condenses on the heater tubes of a Stirling engine, where energy is transferred to the engine`s helium working fluid. Tests on a prototype unit illustrated that a compact (8 cm {times} 13 cm {times} 16 cm) sodium evaporator can routinely transfer 15 kW(t) of energy at an operating vapor temperature of 760 C. Four of these prototype units were eventually used to power a 25-kW(e) Stirling engine system. Design details and test results from the prototype unit are presented in this report.

  2. Soil Evaporation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil evaporation can significantly influence energy flux partitioning of partially vegetated surfaces, ultimately affecting plant transpiration. While important, quantification of soil evaporation, separately from canopy transpiration, is challenging. Techniques for measuring soil evaporation exis...

  3. Leidenfrost Drop on a Step

    NASA Astrophysics Data System (ADS)

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

    2008-11-01

    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.

  4. Experimental investigation of the two-phase flow regimes and pressure drop in horizontal mini-size rectangular test section

    NASA Astrophysics Data System (ADS)

    Elazhary, Amr Mohamed; Soliman, Hassan M.

    2012-10-01

    An experimental study was conducted in order to investigate two-phase flow regimes and fully developed pressure drop in a mini-size, horizontal rectangular channel. The test section was machined in the form of an impacting tee junction in an acrylic block (in order to facilitate visualization) with a rectangular cross-section of 1.87-mm height on 20-mm width on the inlet and outlet sides. Pressure drop measurement and flow regime identification were performed on all three sides of the junction. Air-water mixtures at 200 kPa (abs) and room temperature were used as the test fluids. Four flow regimes were identified visually: bubbly, plug, churn, and annular over the ranges of gas and liquid superficial velocities of 0.04 ≤ JG ≤ 10 m/s and 0.02 ≤ JL ≤ 0.7 m/s, respectively, and a flow regime map was developed. Accuracy of the pressure-measurement technique was validated with single-phase, laminar and turbulent, fully developed data. Two-phase experiments were conducted for eight different inlet conditions and various mass splits at the junction. Comparisons were conducted between the present data and former correlations for the fully developed two-phase pressure drop in rectangular channels with similar sizes. Wide deviations were found among these correlations, and the correlations that agreed best with the present data were identified.

  5. Taking the Easy Way Out: How the GED Testing Program Induces Students to Drop Out

    PubMed Central

    Heckman, James J.; Humphries, John Eric; LaFontaine, Paul A.; Rodríguez, Pedro L.

    2011-01-01

    The option to obtain a General Education Development (GED) certificate changes the incentives facing high school students. This paper evaluates the effect of three different GED policy innovations on high school graduation rates. A six point decrease in the GED pass rate due to an increase in passing standards produced a 1.3 point decline in overall dropout rates. The introduction of a GED certification program in high schools in Oregon produced a four percent decrease in graduation rates. Introduction of GED certificates in California increased dropout rates by 3 points. The GED program induces high school students to drop out. PMID:24634564

  6. X-ray driven evaporation of exoplanet atmospheres: discovery of a uniquely suited test system

    NASA Astrophysics Data System (ADS)

    Poppenhaeger, Katja

    2013-09-01

    The evaporation of exoplanetary atmospheres is thought to be driven by high-energy irradiation. However, the actual mass loss rates are not well constrained. Co-I Kipping has recently discovered that the star KOI-314, an M1V dwarf at 65 pc distance, is orbited by two earth-sized planets, the inner one of them rocky and the outer one gaseous (P_orb = 14d and 23d). Other recent works have shown an abundance of small rocky planets in very close orbits around their host stars, suggesting that the stellar high-energy irradiation evaporates away gaseous envelopes. KOI-314 is the first nearby system in which earth-sized planets of both types are detected, allowing us to constrain the efficiency of planetary evaporation if the stellar X-ray irradiation is measured. We therefore propose a 10 ks Chandra ACIS-S pointing to determine the stellar X-ray luminosity and hardness ratio. The accuracy of the orbital solution decreases quickly due to Transit-Timing Variations, which is why we ask for DDT.

  7. Internuclear cascade-evaporation model for LET spectra of 200 MeV protons used for parts testing

    SciTech Connect

    O`Neill, P.M.; Badhwar, G.D.; Culpepper, W.X.

    1998-12-01

    The Linear Energy Transfer (LET) spectrum produced in microelectronic components during testing with 200 MeV protons is calculated with an internuclear cascade-evaporation code. This spectrum is compared to the natural space heavy ion environment for various earth orbits. This comparison is used to evaluate the results of proton testing in terms of determining a firm upper bound to the on-orbit heavy ion upset rate and the risk of on-orbit heavy ion failures that would not be detected with protons.

  8. Drop tests and numerical impact analyses of new cask designs for High Activity Waste (Haw) and spent fuel - updated BAM design testing experiences

    SciTech Connect

    Volzke, H.; Zencker, U.; Qiao, L.; Feutlinske, K.; Musolff, A.

    2007-07-01

    In Germany, several new cask designs by international vendors (Gesellschaft fuer Nuklear Service mbH (GNS), TN International (TNI), Mitsubishi Heavy Industries (MHI)) are under design testing and within official licensing procedures for transport and storage casks for spent fuel and high activity waste (HAW). BAM (the German Federal Institute for Materials Research and Testing) has been performing several extensive drop test series with prototype casks to evaluate the safety margins against mechanical test conditions. An important project is the new GNS cask design for HAW, the CASTOR{sup R} HAW 28M. Sixteen drop tests have been performed under transport conditions with a 1:2 scale cask model equipped with impact limiters and extensively instrumented with strain gauges and accelerometers. Additionally, the accident scenario inside a storage facility has been investigated by a cask drop without impact limiters onto a nearly unyielding target. This scenario is dominated by highly dynamic effects and interactions between the test object and the target. Complete safety assessments for such mechanical accident scenarios and highly loaded cask structures require additional numerical investigations. They are done by complex finite element (FE) calculations that provide detailed dynamic stress and strain analyses all over the cask structure and at such points where sensors can't be applied. In addition, differences between the material property quantities of the prototype cask and the minimum material property requirements for the cask series production can be investigated as well as dimensional tolerances. By example, the safety assessment method and some of its special aspects are illustrated by the cask drop without an impact limiter onto a hard foundation. The main aspects and challenges are to develop a sufficient computer model of the cask and foundation and to provide detailed interpretation of the large amount of measurement data for achieving good correlation

  9. European type-approval test procedure for evaporative emissions from passenger cars against real-world mobility data from two Italian provinces.

    PubMed

    Martini, Giorgio; Paffumi, Elena; De Gennaro, Michele; Mellios, Giorgos

    2014-07-15

    This paper presents an evaluation of the European type-approval test procedure for evaporative emissions from passenger cars based on real-world mobility data. The study relies on two large databases of driving patterns from conventional fuel vehicles collected by means of on-board GPS systems in the Italian provinces of Modena and Firenze. Approximately 28,000 vehicles were monitored, corresponding to approximately 36 million kilometres over a period of one month. The driving pattern of each vehicle was processed to derive the relation between trip length and parking duration, and the rate of occurrence of parking events against multiple evaporative cycles, defined on the basis of the type-approval test procedure as 12-hour diurnal time windows. These results are used as input for an emission simulation model, which calculates the total evaporative emissions given the characteristics of the evaporative emission control system of the vehicle and the ambient temperature conditions. The results suggest that the evaporative emission control system, fitted to the vehicles from Euro 3 step and optimised for the current type-approval test procedure, could not efficiently work under real-world conditions, resulting in evaporative emissions well above the type-approval limit, especially for small size vehicles and warm climate conditions. This calls for a revision of the type-approval test procedure in order to address real-world evaporative emissions. PMID:24810888

  10. Large scale characterization of unsaturated soil properties in a semi-arid region combining infiltration, pedotransfer functions and evaporation tests

    NASA Astrophysics Data System (ADS)

    Shabou, Marouen; Angulo-Jaramillo, Rafael; Lassabatère, Laurent; Boulet, Gilles; Mougenot, Bernard; Lili Chabaane, Zohra; Zribi, Mehrez

    2016-04-01

    Water resource management is a major issue in semi-arid regions, especially where irrigated agriculture is dominant on soils with highly variable clay content. Indeed, topsoil clay content has a significant importance on infiltration and evaporation processes and therefore in the estimation of the volume of water needed for crops. In this poster we present several methods to estimate wilting point, field capacity volumetric water contents and saturated hydraulic conductivity of the Kairouan plain (680 km2), central Tunisia (North Africa). The first method relies on the Beerkan Estimation of Soil Transfer parameters (BEST) method, which consists in local estimate of unsaturated soil hydraulic properties from a single-ring infiltration test, combined with the use of pedotransfer functions applied to the Kairouan plain different soil types. Results are obtained over six different topsoil texture classes along the Kairouan plain. Saturated hydraulic conductivity is high for coarse textured and some of the fine textured soils due to shrinkage cracking-macropore soil structure. The saturated hydraulic conductivity values are respectively 1.31E-5 m.s-1 and 1.71E-05 m.s-1. The second method is based on evaporation tests on different test plots. It consists of analyzing soil moisture profile changes during the dry down periods to detect the time-to-stress that can be obtained from observation of soil moisture variation, albedo measurements and variation of soil temperature. Results show that the estimated parameters with the evaporation method are close to those obtained by combining the BEST method and pedotransfer functions. The results validate that combining local infiltration tests and pedotransfer functions is a promising tool for the large scale hydraulic characterization of region with strong spatial variability of soils properties.

  11. In vitro comparison of Günther Tulip and Celect filters: testing filtering efficiency and pressure drop.

    PubMed

    Nicolas, M; Malvé, M; Peña, E; Martínez, M A; Leask, R

    2015-02-01

    In this study, the trapping ability of the Günther Tulip and Celect inferior vena cava filters was evaluated. Thrombus capture rates of the filters were tested in vitro in horizontal position with thrombus diameters of 3 and 6mm and tube diameter of 19mm. The filters were tested in centered and tilted positions. Sets of 30 clots were injected into the model and the same process was repeated 20 times for each different condition simulated. Pressure drop experienced along the system was also measured and the percentage of clots captured was recorded. The Günther Tulip filter showed superiority in all cases, trapping almost 100% of 6mm clots both in an eccentric and tilted position and trapping 81.7% of the 3mm clots in a centered position and 69.3% in a maximum tilted position. The efficiency of all filters tested decreased as the size of the embolus decreased and as the filter was tilted. The injection of 6 clots raised the pressure drop to 4.1mmHg, which is a reasonable value that does not cause the obstruction of blood flow through the system. PMID:25553669

  12. Evaporation as a diagnostic test for hydrodynamic cooling of laser-ablated clusters

    SciTech Connect

    Klots, C.E.

    1991-01-01

    The properties of materials laser-ablated from a surface are of considerable interest. The interrogation of these properties inevitably occurs at a point some distance from the surface. One might then ask what processes have occurred in the intervening path length. Immediately, for example, one wonders whether the material was released as such from the surface or was formed as a result of collisions at a distant point. Similarly, one might ask if an observed temperature'' of the materials is characteristic of the ablation process of of subsequent events. We will indicate here how measurements of metastable evaporation rates can provide clues which are pertinent to these questions. 7 refs.

  13. Laboratory prototype flash evaporator

    NASA Technical Reports Server (NTRS)

    Gaddis, J. L.

    1972-01-01

    A laboratory prototype flash evaporator that is being developed as a candidate for the space shuttle environmental control system expendable heat sink is described. The single evaporator configuration uses water as an evaporant to accommodate reentry and on-orbit peak heat loads, and Freon 22 for terrestrial flight phases below 120,000 feet altitude. The design features, fabrication techniques used for the prototype unit, redundancy considerations, and the fluid temperature control arrangement are reported in detail. The results of an extensive test program to determine the evaporator operational characteristics under a wide variety of conditions are presented.

  14. Comparison of ALE and SPH Simulations of Vertical Drop Tests of a Composite Fuselage Section into Water

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fuchs, Yvonne T.

    2008-01-01

    Simulation of multi-terrain impact has been identified as an important research area for improved prediction of rotorcraft crashworthiness within the NASA Subsonic Rotary Wing Aeronautics Program on Rotorcraft Crashworthiness. As part of this effort, two vertical drop tests were conducted of a 5-ft-diameter composite fuselage section into water. For the first test, the fuselage section was impacted in a baseline configuration without energy absorbers. For the second test, the fuselage section was retrofitted with a composite honeycomb energy absorber. Both tests were conducted at a nominal velocity of 25-ft/s. A detailed finite element model was developed to represent each test article and water impact was simulated using both Arbitrary Lagrangian Eulerian (ALE) and Smooth Particle Hydrodynamics (SPH) approaches in LS-DYNA, a nonlinear, explicit transient dynamic finite element code. Analytical predictions were correlated with experimental data for both test configurations. In addition, studies were performed to evaluate the influence of mesh density on test-analysis correlation.

  15. A Comparison of Quasi-Static Indentation and Drop-Weight Impact Testing on Carbon-Epoxy Laminates

    NASA Technical Reports Server (NTRS)

    Prabhakaran, R.

    2001-01-01

    The project had two objectives: 1) The primary objective was to characterize damage tolerance of composite materials. To accomplish this, polymer matrix composites were to be subjected to static indentation as well as low-velocity impacts and the results analyzed. 2) A second objective was to investigate the effects of laser shock peening on the damage tolerance of aerospace materials, such as aluminum alloys, in terms of crack nucleation and crack propagation. The impact testing was proposed to be performed using a Dynatup drop tower. The specimens were to be placed over a square opening in a steel platen and impacted with a hemispherical tup. The damage was to be characterized in the laminate specimens. The damage tolerance of aerospace alloys was to be studied by conducting fatigue tests on aluminum alloy specimens with prior shock peening treatment. The crack length was to be monitored by a microscope and the crack propagation rate, da/dN, determined.

  16. Drop dynamics

    NASA Technical Reports Server (NTRS)

    Elleman, D. D.

    1981-01-01

    The drop dynamics module is a Spacelab-compatible acoustic positioning and control system for conducting drop dynamics experiments in space. It consists basically of a chamber, a drop injector system, an acoustic positioning system, and a data collection system. The principal means of collecting data is by a cinegraphic camera. The drop is positioned in the center of the chamber by forces created by standing acoustic waves generated in the nearly cubical chamber (about 12 cm on a side). The drop can be spun or oscillated up to fission by varying the phse and amplitude of the acoustic waves. The system is designed to perform its experiments unattended, except for start-up and shutdown events and other unique events that require the attention of the Spacelab payload specialist.

  17. Pressure drop testing of corrugated stainless steel pliable gas tubing (PLT)

    NASA Astrophysics Data System (ADS)

    Srinivasan, Bharadwaj

    An experimental program was initiated to determine the Darcy friction factor in straight corrugated stainless steel pliable gas tubing (PLT). Pressure loss tests were conducted on PLT per I.S. EN 15266:2007. A power law least-squares curve fit was used to relate pressure loss per unit length as a function of volume flow rate. The calculated coefficient of determination values for the straight PLT exceeded 0.90 indicating suitable correlation. Darcy friction factors were calculated from test data for each case and plotted on a Moody diagram as a function of Reynolds number based on the minimum PLT cross section. For Reynolds numbers less than 2300 the pressure loss data for PLT yielded an inverse relationship between the Darcy friction factor and the Reynolds number, with a proportionality coefficient of 49. The measurement uncertainty estimates for straight sections was performed with a 95% confidence level. Straight PLT flow rates for air and representative fuel gases that would yield a pressure loss Deltap = 1 mbar were calculated as a function of PLT length and diameter. Fitting pressure loss tests were performed for elbows, tees, and bullhead tees. The loss coefficients were evaluated and tabulated. The calculated coefficient of determination values for the fittings was found to be low. The measurement uncertainty was calculated using the root sum square error method and was found to be very high because of the low flow rates considered in this experiment.

  18. Isotopic Compositions of Evaporative Fluxes

    NASA Astrophysics Data System (ADS)

    Feng, X.; Lauder, A. M.; Kopec, B. G.; Dade, W. B.; Virginia, R. A.; Posmentier, E. S.

    2013-12-01

    The isotopic fluxes of evaporation from a water surface are typically computed using a one-dimensional model, originally conceptualized by Craig and Gordon (1965) and further developed and adapted to different natural settings (such as transpiration, open surface evaporation, etc.) by various investigators. These models have two distinguishing characteristics. First, there exists a laminar layer where molecular diffusion away from the water-air interface causes kinetic isotopic fractionation. The magnitude of this fractionation is controlled by the diffusion/transport coefficient of each vapor isotopologue in air and their concentration gradients, the latter being controlled by relative humidity, isotopic ratios of ambient air, and turbulent conditions (such as wind and surface roughness). Second, the horizontal variations are ignored. In particular, the effect of horizontal advection on isotopic variations in the ambient air is not considered. The research reported here addresses the effects of relinquishing the simplifying assumptions in both of these areas. We developed a model, in which the simplification of a purely laminar layer is dropped. Instead, we express the vertical transport coefficient as the sum of the molecular diffusivity, that differs for each water isotopologue, and the turbulent diffusivity that increases linearly with height but does not vary among water isotopologues. With this model, the kinetic isotopic effect reduces with height in the vicinity of the water surface, and the net isotopic fractionation through the boundary layer can be integrated. The advantage of this conceptualization is that the magnitude of kinetic isotopic fractionation can be assessed directly with changing environmental conditions, such as humidity and wind speed, rather than approximated by discontinuous empirical functions of the environmental conditions, as in the conventional models mentioned above. To address the effect of lateral heterogeneity, we expanded the

  19. Pressure Drop

    NASA Technical Reports Server (NTRS)

    Lawson, Mike

    2010-01-01

    Mike Lawson briefly discussed pressure drop for aerospace applications and presented short stories about adventures experienced while working at NASA and General Dynamics, including exposure to technologies like the Crew and Equipment Translation Aid (CETA) cart and the SWME.

  20. Evaporation from a meniscus within a capillary tube in microgravity

    NASA Technical Reports Server (NTRS)

    Hallinan, K. P.

    1993-01-01

    The following represents a summary of progress made on the project 'Evaporation from a Capillary Meniscus in Microgravity' being conducted at the University of Dayton during the period 1 Dec. 1992 to 30 Nov. 1993. The efforts during this first year of the grant focused upon the following specific tasks: (1) application of a 3-D scattering particle image velocimetry technique to thin film velocity field measurement; (2) modeling the thermo-fluid behavior of the evaporating meniscus in 0-g within large diameter capillaries; (3) conceptualization of the space flight test cell (loop) configuration; (4) construction of prototypes of the test loop configuration; (5) conduct of experiments in 0-g in the 2.2 second drop tower at NASA-LeRC to study evaporation from a capillary meniscus within a square cuvette; and (6) investigation of the effect of vibrations on the stability of the meniscus. An overview of the work completed within these six task areas is presented.

  1. PILOT-SCALE TEST RESULTS OF A THIN FILM EVAPORATOR SYSTEM FOR MANAGEMENT OF LIQUID HIGH-LEVEL WASTES AT THE HANFORD SITE WASHINGTON USA -11364

    SciTech Connect

    CORBETT JE; TEDESCH AR; WILSON RA; BECK TH; LARKIN J

    2011-02-14

    A modular, transportable evaporator system, using thin film evaporative technology, is planned for deployment at the Hanford radioactive waste storage tank complex. This technology, herein referred to as a wiped film evaporator (WFE), will be located at grade level above an underground storage tank to receive pumped liquids, concentrate the liquid stream from 1.1 specific gravity to approximately 1.4 and then return the concentrated solution back into the tank. Water is removed by evaporation at an internal heated drum surface exposed to high vacuum. The condensed water stream will be shipped to the site effluent treatment facility for final disposal. This operation provides significant risk mitigation to failure of the aging 242-A Evaporator facility; the only operating evaporative system at Hanford maximizing waste storage. This technology is being implemented through a development and deployment project by the tank farm operating contractor, Washington River Protection Solutions (WRPS), for the Office of River Protection/Department of Energy (ORPIDOE), through Columbia Energy and Environmental Services, Inc. (Columbia Energy). The project will finalize technology maturity and install a system at one of the double-shell tank farms. This paper summarizes results of a pilot-scale test program conducted during calendar year 2010 as part of the ongoing technology maturation development scope for the WFE.

  2. Evaluation of low-velocity impact tests of solid steel billet onto concrete pads, and application to generic ISFSI storage cask for tipover and side drop

    SciTech Connect

    Witte, M. C.; Chen, T.F.; Mok, G.C.; Murty, S.S.; Fischer, L.E.

    1997-03-01

    Spent Fuel Storage Casks intended for use at Independent Spent Fuel Storage Installations (ISFSIS) typically are evaluated during the application and review process for low-energy impacts representative of possible handling accidents including tipover events. In the past, the analyses involved in these evaluations have assumed that the casks dropped or tipped onto an unyielding surface, a conservative and simplifying assumption. Since 10 CFR Part 72`, the regulation imposed by the Nuclear Regulatory Commission (NRC), does not require this assumption, applicants are currently seeking a more realistic model for the analyses and are using analytical models which predict the effect of a cask dropping onto a reinforced concrete pad, including energy absorbing aspects such as cracking and flexure. In order to develop data suitable for benchmarking these analyses, the NRC has conducted several series of drop-test studies. The tests described in this report were primarily intended to determine the response characteristics of concrete pads during tipover and side impacts of a solid steel billet onto the pads. This series of tests is fourth in a program of tests funded by the NRC; all four series of tests address issues of impact involving spent fuel storage casks. The first series was performed in March 1993 by Sandia National Laboratories (SNL) and involved five end-drops of a billet, nearly identical to the one used in the present series, onto a variety of surfaces from a height of 18 inches. The second series of tests was performed between July and October 1993, and involved four end- drops of a near-full-scale empty Excellox 3A cask onto a full-scale concrete pad and foundation, or onto an essentially unyielding surface, from heights ranging from 18 inches to 60 inches, and was conducted by the British Nuclear Fuels Limited in Winfrith, England. (Two of the drops in the second series were sponsored by Electric Power Research Institute.) The third test series was

  3. Drop Tower Physics

    NASA Astrophysics Data System (ADS)

    Dittrich, William A. Toby

    2014-10-01

    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.

  4. Testing the Craig and Gordon model with field measurements of oxygen isotope ratios of evaporative fluxes in a Mediterranean oak savannah to partition evapotranspiration

    NASA Astrophysics Data System (ADS)

    Dubbert, Maren; Matthias, Cuntz; Arndt, Piayda; Christane, Werner

    2013-04-01

    Stable oxygen isotopes of water provide a valuable tracer for water movements within ecosystems and are used to estimate the contribution of transpiration to total ecosystem evapotranspiration (ft). We tested the Craig and Gordon equation against continuous field measurements of isotopic composition of evaporation and assessed the impact for partitioning evapotranspiration. Therefore, evaporation (E) and its isotopic signature (δ18OE) on bare soil plots, as well as evapotranspiration (ET) and its corresponding isotopic composition of (δ18OET) of an herbaceous understory layer was measured with a cavity ring-down spectrometer connected to a soil chamber on a field site in central Portugal. We quantified the variation in δ18OE arising from uncertainties in the determination of environmental input variables to the Craig and Gordon equation: the isotope signature at the evaporating site (δ18Oe), the temperature at the evaporating site (Te), and the kinetic fractionation factor (αk). We could hence quantify ft based on measured δ18OET, modeled δ18OE from observed soil water isotopic composition at the evaporating site (δ18Oe), and modeled δ18O of transpiration (δ18OT) from observed total soil water isotopic composition. Our results demonstrate that predicting δ18OE using the Craig and Gordon equation leads to good agreement with measured δ18OE given that the temperature and isotope profiles of the soil are thoroughly characterized. However, modeled δ18OE is highly sensitive to changes in Te and δ18Oe as well as αk. This markedly affected the partition results of transpiration and evaporation from the total ET flux: The fraction of transpiration (ft) varied strongly using different formulations for αk and assuming steady or non-steady state transpiration. These findings provide a first comparison of laser-based and modeled isotopic compositions of evaporation based on the Craig and Gordon equation under field conditions. This is of special interest for

  5. Pattern formation in drying drops of blood

    NASA Astrophysics Data System (ADS)

    Brutin, D.; Sobac, B.; Loquet, B.; Sampol, J.

    2011-01-01

    The drying of a drop of human blood exhibits coupled physical mechanisms, such as Marangoni flow, evaporation and wettability. The final stage of a whole blood drop evaporation reveals regular patterns with a good reproducibility for a healthy person. Other experiments on anaemic and hyperlipidemic people were performed, and different patterns were revealed. The flow motion inside the blood drop is observed and analyzed with the use of a digital camera: the influence of the red blood cells (RBCs) motion is revealed at the drop periphery as well as its consequences on the final stage of drying. The mechanisms which lead to the final pattern of the dried blood drops are presented and explained on the basis of fluid mechanics in conjunction with the principles of haematology. The blood drop evaporation process is evidenced to be driven only by Marangoni flow. The same axisymetric pattern formation is observed, and can be forecast for different blood drop diameters. The evaporation mass flux can be predicted with a good agreement, assuming only the knowledge of the colloids mass concentration.

  6. 3D FEM Simulations of Drop Test Reliability on 3D-WLP: Effects of Solder Reflow Residual Stress and Molding Resin Parameters

    NASA Astrophysics Data System (ADS)

    Belhenini, Soufyane; Tougui, Abdellah; Bouchou, Abdelhake; Mohan, Ranganathan; Dosseul, Franck

    2014-01-01

    Numerous three-dimensional (3D) packaging technologies are currently used for 3D integration. 3D-wafer level package (3D-WLP) appears to be a way to keep increasing the density of the microelectronic components. The reliability of 3D components has to be evaluated on mechanical demonstrators with daisy chains before real production. Numerical modeling is acknowledged as a very efficient tool for design optimization. In this paper, 3D finite-elements calculations are carried out to analyze the effects of molding resin's mechanical properties and thickness on the 3D component's dynamic response under drop loading conditions. Residual stress generated by solder reflow is also discussed. The influences of residual stresses on the numerical estimation of the component behavior during drop loading are studied. Solder reflow residual stresses have an impact on solder plastic strain and die equivalent stress calculations. We have compared the result of two numerical drop test models. Stress-free initial conduction is introduced for the first model. Solder reflow residual stresses are considered as the initial condition for the second drop test model. Quantitative and qualitative comparisons are carried out to show the effect of residual stress in drop test calculations. For the effect of molding resin thickness on the component behavior under drop loading, the stress-free initial condition is considered. The effect of the molding resin's thickness on critical area location is discussed. The solder bump maximum plastic shear strain and the silicon die maximum equivalent stress are used as reliability criteria. Numerical submodeling techniques are used to increase calculation accuracy. Numerical results have contributed to the design optimization of the 3D-WLP component.

  7. Testing data evaluation strategies for estimating precipitation and actual evaporation from precision lysimeter measurements

    NASA Astrophysics Data System (ADS)

    Schrader, Frederik; Durner, Wolfgang; Fank, Johann; Pütz, Thomas; Wollschläger, Ute

    2014-05-01

    across the soil-atmosphere boundary from lysimeter data. To test how different strategies of data processing perform under various circumstances, we used numerical simulation to generate synthetic data and corrupted these with three different noise patterns of increasing complexity. We found that traditional low-pass filtering approaches are not very well suited for our use case. However, an additional threshold-based separation of P and ET after initial smoothing appears to work considerably better and more robust, while still being straightforward to implement. A third, more sophisticated approach proposed by Peters (2013) that extends on this method by data driven parameter scaling, should be subject to further research. Based on our preliminary findings, we suggest reducing degrees-of-freedom of this strategy.

  8. Representative shuttle evaporative heat sink

    NASA Technical Reports Server (NTRS)

    Hixon, C. W.

    1978-01-01

    The design, fabrication, and testing of a representative shuttle evaporative heat sink (RSEHS) system which vaporizes an expendable fluid to provide cooling for the shuttle heat transport fluid loop is reported. The optimized RSEHS minimum weight design meets or exceeds the shuttle flash evaporator system requirements. A cold trap which cryo-pumps flash evaporator exhaust water from the CSD vacuum chamber test facility to prevent water contamination of the chamber pumping equipment is also described.

  9. Testing the generalized complementary relationship of evaporation with continental-scale long-term water-balance data

    NASA Astrophysics Data System (ADS)

    Szilagyi, Jozsef; Crago, Richard; Qualls, Russell J.

    2016-09-01

    The original and revised versions of the generalized complementary relationship (GCR) of evaporation (ET) were tested with six-digit Hydrologic Unit Code (HUC6) level long-term (1981-2010) water-balance data (sample size of 334). The two versions of the GCR were calibrated with Parameter-Elevation Regressions on Independent Slopes Model (PRISM) mean annual precipitation (P) data and validated against water-balance ET (ETwb) as the difference of mean annual HUC6-averaged P and United States Geological Survey HUC6 runoff (Q) rates. The original GCR overestimates P in about 18% of the PRISM grid points covering the contiguous United States in contrast with 12% of the revised version. With HUC6-averaged data the original version has a bias of -25 mm yr-1 vs the revised version's -17 mm yr-1, and it tends to more significantly underestimate ETwb at high values than the revised one (slope of the best fit line is 0.78 vs 0.91). At the same time it slightly outperforms the revised version in terms of the linear correlation coefficient (0.94 vs 0.93) and the root-mean-square error (90 vs 92 mm yr-1).

  10. Drop Reliability of Epoxy-contained Sn-58 wt.%Bi Solder Joint with ENIG and ENEPIG Surface Finish Under Temperature and Humidity Test

    NASA Astrophysics Data System (ADS)

    Myung, Woo-Ram; Kim, Yongil; Kim, Kyung-Yeol; Jung, Seung-Boo

    2016-04-01

    The influence of two kinds of surface finish, namely electroless nickel immersion gold (ENIG) and electroless nickel electroless palladium immersion gold (ENEPIG), on the interfacial reactions and drop reliability of epoxy-enhanced Sn-58 wt.%Bi solder has been investigated after temperature-humidity storage tests. The chemical composition and morphology of intermetallic compounds (IMCs) were characterized by scanning electron microscopy, energy-dispersive x-ray spectroscopy, and electron probe microanalysis. Also, the mechanical reliability of solder joints was evaluated using board-level drop tests. The Sn-Bi epoxy solder/ENEPIG joint exhibited higher IMC growth rate than the Sn-Bi epoxy solder/ENIG joint. After 500 h at 85°C/85% RH storage condition, new IMCs were formed on the Ni3Sn4 layer in samples with both surface finishes. The results of board-level drop tests showed that the number of drops was higher for the ENIG than the ENEPIG surface finish. Solder joint fracture occurred along the interface between the solder and IMC layer for the ENIG surface finish. However, with the ENEPIG surface finish, the crack propagated between the IMCs.

  11. Drop Reliability of Epoxy-contained Sn-58 wt.%Bi Solder Joint with ENIG and ENEPIG Surface Finish Under Temperature and Humidity Test

    NASA Astrophysics Data System (ADS)

    Myung, Woo-Ram; Kim, Yongil; Kim, Kyung-Yeol; Jung, Seung-Boo

    2016-07-01

    The influence of two kinds of surface finish, namely electroless nickel immersion gold (ENIG) and electroless nickel electroless palladium immersion gold (ENEPIG), on the interfacial reactions and drop reliability of epoxy-enhanced Sn-58 wt.%Bi solder has been investigated after temperature-humidity storage tests. The chemical composition and morphology of intermetallic compounds (IMCs) were characterized by scanning electron microscopy, energy-dispersive x-ray spectroscopy, and electron probe microanalysis. Also, the mechanical reliability of solder joints was evaluated using board-level drop tests. The Sn-Bi epoxy solder/ENEPIG joint exhibited higher IMC growth rate than the Sn-Bi epoxy solder/ENIG joint. After 500 h at 85°C/85% RH storage condition, new IMCs were formed on the Ni3Sn4 layer in samples with both surface finishes. The results of board-level drop tests showed that the number of drops was higher for the ENIG than the ENEPIG surface finish. Solder joint fracture occurred along the interface between the solder and IMC layer for the ENIG surface finish. However, with the ENEPIG surface finish, the crack propagated between the IMCs.

  12. Electrostatic Positioning System for a free fall test at drop tower Bremen and an overview of tests for the Weak Equivalence Principle in past, present and future

    NASA Astrophysics Data System (ADS)

    Sondag, Andrea; Dittus, Hansjörg

    2016-08-01

    The Weak Equivalence Principle (WEP) is at the basis of General Relativity - the best theory for gravitation today. It has been and still is tested with different methods and accuracies. In this paper an overview of tests of the Weak Equivalence Principle done in the past, developed in the present and planned for the future is given. The best result up to now is derived from the data of torsion balance experiments by Schlamminger et al. (2008). An intuitive test of the WEP consists of the comparison of the accelerations of two free falling test masses of different composition. This has been carried through by Kuroda & Mio (1989, 1990) with the up to date most precise result for this setup. There is still more potential in this method, especially with a longer free fall time and sensors with a higher resolution. Providing a free fall time of 4.74 s (9.3 s using the catapult) the drop tower of the Center of Applied Space Technology and Microgravity (ZARM) at the University of Bremen is a perfect facility for further improvements. In 2001 a free fall experiment with high sensitive SQUID (Superconductive QUantum Interference Device) sensors tested the WEP with an accuracy of 10-7 (Nietzsche, 2001). For optimal conditions one could reach an accuracy of 10-13 with this setup (Vodel et al., 2001). A description of this experiment and its results is given in the next part of this paper. For the free fall of macroscopic test masses it is important to start with precisely defined starting conditions concerning the positions and velocities of the test masses. An Electrostatic Positioning System (EPS) has been developed to this purpose. It is described in the last part of this paper.

  13. Development drop test results of the 15-ft-dia ribbon parachute and 73-ft-dia cross parachute for the US Army Natick Laboratory UHLCADS system

    SciTech Connect

    Pepper, W.B.

    1985-09-01

    During 1984 a series of 12 drop tests was conducted at the US Army Yuma Proving Ground near Yuma, Arizona to develop a new system to recover a 2200-lb resupply container from high altitude. The parachute system consists of a 15-ft-dia ribbon parachute reefed for 10 s and a 73-ft-dia cross parachute with no reefing. The system has been successfully demonstrated by flight tests. The impact velocity is 30 fps.

  14. Pool impacts of Leidenfrost drop

    NASA Astrophysics Data System (ADS)

    Darbois Texier, Baptiste; Maquet, Laurent; Dorbolo, Stephane; Dehandschoewercker, Eline; Pan, Zhao; Truscott, Tadd

    2015-11-01

    This work concerns the impact of a droplet made of a volatile liquid (typically HFE) on a pool of an other liquid (typically silicone oil) which temperature is above the boiling point of the drop. Depending on the properties of the two liquids and the impacting conditions, four different regimes are observed. For low impacting speeds, the droplet bounces on the surface of the bath and finally levitates above it in a Leidenfrost state. Such a regime occurs as soon as the pool temperature exceeds the boiling point of the drop. This observation means that there is no threshold in temperature for a Leidenfrost effect on a liquid surface contrary to the case of a solid substrate. For intermediate impacting velocities, the pinch-off of the surface of the pool entraps the drop in the liquid bulk. The entrapped drop is separated from the pool by a layer of its own vapour in a similar way of antibulles. For increasing impacting speeds, the vapour layer between the drop and the pool does not hold during the pinch-off event. The contact of the drop with the hot liquid provokes a sudden and intense evaporation. At very large impacting speeds, the drop rapidely contacts the pool, spreads and finally induces a hemi-spherical cavity. In the end, these four different regimes are summarized in a Froud-Weber diagram which boundaries are discussed.

  15. An Experimental Study of Pressure Oscillation in a Capillary Pumped Loop with Multiple Evaporators and Condensers

    NASA Technical Reports Server (NTRS)

    Ku, Jen-Tung; Hoang, Triem T.

    1998-01-01

    The heat transport capability of a capillary pumped loop (CPL) is limited by the pressure drop that its evaporator wick can sustain. The pressure drop in a CPL is not constant even under seemingly steady operation, but rather exhibits an oscillatory behavior. A hydrodynamic theory based on a mass-spring-dashpot model was previously developed to predict the pressure oscillation in a CPL with a single evaporator and a single condenser. The theory states that the pressure oscillation is a function of physical dimensions of the CPL components and operating conditions. Experimental data agreed very well with theoretical predictions. The hydrodynamic stability theory has recently been extended to predict the pressure oscillations in CPLs with multiple evaporators and multiple condensers. Concurrently, an experimental study was conducted to verify the theory and to investigate the effects of various parameters on the pressure oscillation. Four evaporators with different wick properties were tested using a test loop containing two condenser plates. The test loop allowed the four evaporators to be tested in a single-pump, two-pump or four-pump configuration, and the two condenser plates to be plumbed either in parallel or in series. Test conditions included varying the power input, the reservoir set point temperature, the condenser sink temperature, and the flow resistance between the reservoir and the loop. Experimental results agreed well with theoretical predictions.

  16. Evaporating firewalls

    NASA Astrophysics Data System (ADS)

    Van Raamsdonk, Mark

    2014-11-01

    In this note, we begin by presenting an argument suggesting that large AdS black holes dual to typical high-energy pure states of a single holographic CFT must have some structure at the horizon, i.e. a fuzzball/firewall, unless the procedure to probe physics behind the horizon is state-dependent. By weakly coupling the CFT to an auxiliary system, such a black hole can be made to evaporate. In a case where the auxiliary system is a second identical CFT, it is possible (for specific initial states) that the system evolves to precisely the thermofield double state as the original black hole evaporates. In this case, the dual geometry should include the "late-time" part of the eternal AdS black hole spacetime which includes smooth spacetime behind the horizon of the original black hole. Thus, if a firewall is present initially, it evaporates. This provides a specific realization of the recent ideas of Maldacena and Susskind that the existence of smooth spacetime behind the horizon of an evaporating black hole can be enabled by maximal entanglement with a Hawking radiation system (in our case the second CFT) rather than prevented by it. For initial states which are not finely-tuned to produce the thermofield double state, the question of whether a late-time infalling observer experiences a firewall translates to a question about the gravity dual of a typical high-energy state of a two-CFT system.

  17. Salt stains from evaporating droplets.

    PubMed

    Shahidzadeh, Noushine; Schut, Marthe F L; Desarnaud, Julie; Prat, Marc; Bonn, Daniel

    2015-01-01

    The study of the behavior of sessile droplets on solid substrates is not only associated with common everyday phenomena, such as the coffee stain effect, limescale deposits on our bathroom walls , but also very important in many applications such as purification of pharmaceuticals, de-icing of airplanes, inkjet printing and coating applications. In many of these processes, a phase change happens within the drop because of solvent evaporation, temperature changes or chemical reactions, which consequently lead to liquid to solid transitions in the droplets. Here we show that crystallization patterns of evaporating of water drops containing dissolved salts are different from the stains reported for evaporating colloidal suspensions. This happens because during the solvent evaporation, the salts crystallize and grow during the drying. Our results show that the patterns of the resulting salt crystal stains are mainly governed by wetting properties of the emerging crystal as well as the pathway of nucleation and growth, and are independent of the evaporation rate and thermal conductivity of the substrates. PMID:26012481

  18. Salt stains from evaporating droplets

    PubMed Central

    Shahidzadeh, Noushine; Schut, Marthe F. L.; Desarnaud, Julie; Prat, Marc; Bonn, Daniel

    2015-01-01

    The study of the behavior of sessile droplets on solid substrates is not only associated with common everyday phenomena, such as the coffee stain effect, limescale deposits on our bathroom walls , but also very important in many applications such as purification of pharmaceuticals, de-icing of airplanes, inkjet printing and coating applications. In many of these processes, a phase change happens within the drop because of solvent evaporation, temperature changes or chemical reactions, which consequently lead to liquid to solid transitions in the droplets. Here we show that crystallization patterns of evaporating of water drops containing dissolved salts are different from the stains reported for evaporating colloidal suspensions. This happens because during the solvent evaporation, the salts crystallize and grow during the drying. Our results show that the patterns of the resulting salt crystal stains are mainly governed by wetting properties of the emerging crystal as well as the pathway of nucleation and growth, and are independent of the evaporation rate and thermal conductivity of the substrates. PMID:26012481

  19. DROP TESTS RESULTS OF REVISED CLOSURE BOLT CONFIGURATION OF THE STANDARD WASTE BOX, STANDARD LARGE BOX 2, AND TEN DRUM OVERPACK PACKAGINGS

    SciTech Connect

    May, C.; Opperman, E.; Mckeel, C.

    2010-04-15

    The Transuranic (TRU) Disposition Project at Savannah River Site will require numerous transfers of radioactive materials within the site boundaries for sorting and repackaging. The three DOT Type A shipping packagings planned for this work have numerous bolts for securing the lids to the body of the packagings. In an effort to reduce operator time to open and close the packages during onsite transfers, thus reducing personnel exposure and costs, an evaluation was performed to analyze the effects of reducing the number of bolts required to secure the lid to the packaging body. The evaluation showed the reduction to one-third of the original number of bolts had no effect on the packagings capability to sustain vibratory loads, shipping loads, internal pressure loads, and the loads resulting from a 4-ft drop. However, the loads caused by the 4-ft drop are difficult to estimate and the study recommended each of the packages be dropped to show the actual effects on the package closure. Even with reduced bolting, the packagings were still required to meet the 49 CFR 178.350 performance criteria for Type A packaging. This paper discusses the effects and results of the drop testing of the three packagings.

  20. Rain Drop Charge Sensor

    NASA Astrophysics Data System (ADS)

    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

  1. Design and characterization of large-drop generators for viscous, Newtonian, and non-Newtonian liquids

    NASA Astrophysics Data System (ADS)

    Pitter, Richard L.; Hoffer, Thomas E.; Allan, Craig R.; Carlon, Hugh R.; Stuempfle, Arthur K.

    1989-03-01

    Work performed by contractor personnel in conjunction with CRDEC Engineering Center (CRDEC) scientists is described. To evaluate protective clothing and the effects of chemical aerosols dispersed over a battlefield, a physical testing facility capable of simulating the behavior of falling drops is needed. In such a facility, the effects of drop size, surface interactions, long-term evaporation, and similar phenomena can be studied. This report describes two drop generators developed at the Desert Research Institute (DRI) and one drop generator developed at CRDEC. The first generator uses a drop injection of impulse technique and is appropriate for a wide variety of drop sizes using Newtonian liquids of various viscosities. The drop ejection technique has been improved in this work. The second generator uses a unique, two-step process. A microfilm is formed across a horizontal loop, and the test liquid is extruded onto the microfilm surface. The liquid drop is released into freefall by a short burst of solvent directed at the loop, causing the microfilm to disintegrate.

  2. Streamer Evaporation

    NASA Technical Reports Server (NTRS)

    Suess, S. T.; Wang, A.-H.; Wu, S. T.; Nerney, S. F.

    1998-01-01

    Evaporation is the consequence of heating near the top of streamers in ideal Magnetohydrodynamics (MHD) models, where the plasma is weakly contained by the magnetic field. Heating causes slow opening of field lines and release of new solar wind. It was discovered in simulations and, due to the absence of loss mechanisms, the ultimate end point is the complete evaporation of the streamer. Of course streamers do not behave in this way because there are losses by thermal conduction and radiation. Physically, heating is also expected to depend on ambient conditions. We use our global MHD model with thermal conduction to examine the effect of changing the heating scale height. We also apply and extend an analytic model of streamers developed by Pneuman (1968) to show that steady streamers are unable to contain plasma for temperatures near the cusp greater than approximately 2 x 10(exp 6) K.

  3. A Test of Outreach and Drop-in Linkage Versus Shelter Linkage for Connecting Homeless Youth to Services.

    PubMed

    Slesnick, Natasha; Feng, Xin; Guo, Xiamei; Brakenhoff, Brittany; Carmona, Jasmin; Murnan, Aaron; Cash, Scottye; McRee, Annie-Laurie

    2016-05-01

    Outreach and service linkage are key for engaging marginalized populations, such as homeless youth, in services. Research to date has focused primarily on engaging individuals already receiving some services through emergency shelters, clinics, or other programs. Less is known about those who are not connected to services and, thus, likely the most vulnerable and in need of assistance. The current study sought to engage non-service-connected homeless youth (N = 79) into a strengths-based outreach and advocacy intervention. Youth were randomly assigned to receive 6 months of advocacy that focused on linking youth to a drop-in center (n = 40) or to a crisis shelter (n = 39). All youth were assessed at baseline and 3, 6, and 9 months post-baseline. Findings indicated that youth prefer drop-in center services to the shelter. Also, the drop-in center linkage condition was associated with more service linkage overall (B = 0.34, SE = 0.04, p < 0.01) and better alcohol-l [B = -0.39, SE = 0.09, t(75) = -4.48, p < 0.001] and HIV-related outcomes [B = 0.62, SE = 0.10, t(78) = 6.34, p < 0.001] compared to the shelter linkage condition. Findings highlight the importance of outreach and service linkage for reconnecting service-marginalized youth, and drop-in centers as a primary service option for homeless youth. PMID:26759145

  4. Group evaporation

    NASA Technical Reports Server (NTRS)

    Shen, Hayley H.

    1991-01-01

    Liquid fuel combustion process is greatly affected by the rate of droplet evaporation. The heat and mass exchanges between gas and liquid couple the dynamics of both phases in all aspects: mass, momentum, and energy. Correct prediction of the evaporation rate is therefore a key issue in engineering design of liquid combustion devices. Current analytical tools for characterizing the behavior of these devices are based on results from a single isolated droplet. Numerous experimental studies have challenged the applicability of these results in a dense spray. To account for the droplets' interaction in a dense spray, a number of theories have been developed in the past decade. Herein, two tasks are examined. One was to study how to implement the existing theoretical results, and the other was to explore the possibility of experimental verifications. The current theoretical results of group evaporation are given for a monodispersed cluster subject to adiabatic conditions. The time evolution of the fluid mechanic and thermodynamic behavior in this cluster is derived. The results given are not in the form of a subscale model for CFD codes.

  5. Organization of microbeads in Leidenfrost drops.

    PubMed

    Maquet, Laurent; Colinet, Pierre; Dorbolo, Stéphane

    2014-06-21

    We investigated the organization of micrometric hydrophilic beads (glass or basalt) immersed in Leidenfrost drops. Starting from a large volume of water compared to the volume of the beads, while the liquid evaporates, we observed that the grains are eventually trapped at the interface of the droplet and accumulate. At a moment, the grains entirely cover the droplet. We measured the surface area at this moment as a function of the total mass of particles inserted in the droplet. We concluded that the grains form a monolayer around the droplet assuming (i) that the packing of the beads at the surface is a random close packing and (ii) that the initial surface of the drop is larger than the maximum surface that the beads can cover. Regarding the evaporation dynamics, the beads are found to reduce the evaporation rate of the drop. The slowdown of the evaporation is interpreted as being the consequence of the dewetting of the particles located at the droplet interface which makes the effective surface of evaporation smaller. As a matter of fact, contact angles of the beads with the water deduced from the evaporation rates are consistent with contact angles of beads directly measured at a flat air-water interface of water in a container. PMID:24705688

  6. Chemical analysis of acoustically levitated drops by Raman spectroscopy.

    PubMed

    Tuckermann, Rudolf; Puskar, Ljiljana; Zavabeti, Mahta; Sekine, Ryo; McNaughton, Don

    2009-07-01

    An experimental apparatus combining Raman spectroscopy with acoustic levitation, Raman acoustic levitation spectroscopy (RALS), is investigated in the field of physical and chemical analytics. Whereas acoustic levitation enables the contactless handling of microsized samples, Raman spectroscopy offers the advantage of a noninvasive method without complex sample preparation. After carrying out some systematic tests to probe the sensitivity of the technique to drop size, shape, and position, RALS has been successfully applied in monitoring sample dilution and preconcentration, evaporation, crystallization, an acid-base reaction, and analytes in a surface-enhanced Raman spectroscopy colloidal suspension. PMID:19418043

  7. Evaluation of impact limiter performance during end-on and slapdown drop tests of a one-third scale model storage/transport cask system

    SciTech Connect

    Yoshimura, H.R.; Bronowski, D.R.; Uncapher, W.L.; Attaway, S.W.; Bateman, V.I.; Carne, T.G.; Gregory, D.L. ); Huerta, M. )

    1990-12-01

    This report describes drop testing of a one-third scale model shipping cask system. Two casks were designed and fabricated by Transnuclear, Inc., to ship spent fuel from the former Nuclear Fuel Services West Valley reprocessing facility in New York to the Idaho National Engineering Laboratory for a long-term spent fuel dry storage demonstration project. As part of the NRC's regulatory certification process, one-third scale model tests were performed to obtain experimental data on impact limiter performance during impact testing. The objectives of the testing program were to (1) obtain deceleration and displacement information for the cask and impact limiter system, (2) obtain dynamic force-displacement data for the impact limiters, (3) verify the integrity of the impact limiter retention system, and (4) examine the crush behavior of the limiters. Two 30-ft (9-m) drop tests were conducted on a mass model of the cask body and scaled balsa and redwood-filled impact limiters. This report describes the results of both tests in terms of measured decelerations, posttest deformation measurements, and the general structural response of the system. 3 refs., 32 figs.

  8. Impact on Ocular Surface Evaporation of an Artificial Tear Solution Containing Hydroxypropyl (HP) Guar

    PubMed Central

    Uchiyama, Eduardo; Di Pascuale, Mario A.; Butovich, Igor A.; McCulley, James P.

    2009-01-01

    OBJECTIVE To determine whether any acute effects on evaporative parameters are produced when using a solution containing Hydroxypropyl (HP) (Systane) versus normal saline solution in the eyes of patients with Keratoconjunctivis Sicca (KCS) at 30 and 60 minutes post instillation. METHODS Randomized double-blinded placebo-control 2-period cross-over clinical trial. Twelve patients with a clinical diagnosis of KCS were enrolled in this study. Aqueous tear evaporation was measured at baseline, i.e., before the application of drops on the eye, and at 30 and 60 minutes after instillation of one 40μl drop of either the HP-Guar containing drop or normal saline on two separate days. Statistical analysis included descriptive data analysis and paired t test. RESULTS HP-Guar resulted in a decrease in aqueous tear evaporation at 30 minutes post instillation under 25–35% relative humidity (RH) (13.2% reduction, p =0.044) and 35–45% RH (10% reduction, p=0.028) conditions. The effect of HP-Guar at 60 minutes post instillation also decreased aqueous tear evaporation but to a lesser degree. Normal saline solution produced no statistically significant increases and decreases of evaporation. CONCLUSIONS Aqueous tear evaporation contributes significantly to aqueous tear loss and is humidity dependent. An HP-guar containing solution decreased aqueous tear evaporation 30 and 60 minutes after application. The use of topical medication with known antievaporative effect may be beneficial in dry eye therapy. This effect may also be achieved in normal eyes or sub-clinical dry eyes when in low RH environments. PMID:18997543

  9. Effects of Constituents and Lay-up Configuration on Drop-Weight Tests of Fiber-Metal Laminates

    NASA Astrophysics Data System (ADS)

    Liu, Yanxiong; Liaw, Benjamin

    2010-02-01

    Impact responses and damage of various fiber-metal laminates were studied using a drop-weight instrument with the post-impact damage characteristics being evaluated through ultrasonic and mechanical sectioning techniques. The first severe failure induced by the low-velocity drop-weight impact occurred as delamination between the aluminum and fiber-epoxy layers at the non-impact side. It was followed by a visible shear crack in the outer aluminum layer on the non-impact face. Through-thickness shear cracks in the aluminum sheets and severe damage in the fiber laminated layers (including delamination between adjacent fiber-epoxy laminae with different fiber orientations) developed under higher energy impacts. The impact properties of fiber-metal laminates varied with different constituent materials and fiber orientations. Since it was punched through easily, the aramid-fiber reinforced fiber-metal laminates (ARALL) offered poorer impact resistance than the glass-fiber reinforced fiber-metal laminates (GLARE). Tougher and more ductile aluminum alloys improved the impact resistance. GLARE made of cross-ply prepregs provided better impact resistance than GLARE with unidirectional plies.

  10. SLURRY MIX EVAPORATOR BATCH ACCEPTABILITY AND TEST CASES OF THE PRODUCT COMPOSITION CONTROL SYSTEM WITH THORIUM AS A REPORTABLE ELEMENT

    SciTech Connect

    Edwards, T.

    2010-10-07

    The Defense Waste Processing Facility (DWPF), which is operated by Savannah River Remediation, LLC (SRR), has recently begun processing Sludge Batch 6 (SB6) by combining it with Frit 418 at a nominal waste loading (WL) of 36%. A unique feature of the SB6/Frit 418 glass system, as compared to the previous glass systems processed in DWPF, is that thorium will be a reportable element (i.e., concentrations of elemental thorium in the final glass product greater than 0.5 weight percent (wt%)) for the resulting wasteform. Several activities were initiated based upon this unique aspect of SB6. One of these was an investigation into the impact of thorium on the models utilized in DWPF's Product Composition and Control System (PCCS). While the PCCS is described in more detail below, for now note that it is utilized by Waste Solidification Engineering (WSE) to evaluate the acceptability of each batch of material in the Slurry Mix Evaporator (SME) before this material is passed on to the melter. The evaluation employs models that predict properties associated with processability and product quality from the composition of vitrified samples of the SME material. The investigation of the impact of thorium on these models was conducted by Peeler and Edwards [1] and led to a recommendation that DWPF can process the SB6/Frit 418 glass system with ThO{sub 2} concentrations up to 1.8 wt% in glass. Questions also arose regarding the handling of thorium in the SME batch acceptability process as documented by Brown, Postles, and Edwards [2]. Specifically, that document is the technical bases of PCCS, and while Peeler and Edwards confirmed the reliability of the models, there is a need to confirm that the current implementation of DWPF's PCCS appropriately handles thorium as a reportable element. Realization of this need led to a Technical Task Request (TTR) prepared by Bricker [3] that identified some specific SME-related activities that the Savannah River National Laboratory (SRNL) was

  11. Critical point wetting drop tower experiment

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

    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.

  12. Streamer Evaporation

    NASA Technical Reports Server (NTRS)

    Suess, Steven T.; Wang, A. H.; Wu, Shi T.; Nerney, S.

    1998-01-01

    Evaporation is the consequence of slow plasma heating near the tops of streamers where the plasma is only weakly contained by the magnetic field. The form it takes is the slow opening of field lines at the top of the streamer and transient formation of new solar wind. It was discovered in polytropic model calculations, where due to the absence of other energy loss mechanisms in magnetostatic streamers, its ultimate endpoint is the complete evaporation of the streamer. This takes, for plausible heating rates, weeks to months in these models. Of course streamers do not behave this way, for more than one reason. One is that there are losses due to thermal conduction to the base of the streamer and radiation from the transition region. Another is that streamer heating must have a characteristic time constant and depend on the ambient physical conditions. We use our global Magnetohydrodynamics (MHD) model with thermal conduction to examine a few examples of the effect of changing the heating scale height and of making ad hoc choices for how the heating depends on ambient conditions. At the same time, we apply and extend the analytic model of streamers, which showed that streamers will be unable to contain plasma for temperatures near the cusp greater than about 2xl0(exp 6) K. Slow solar wind is observed to come from streamers through transient releases. A scenario for this that is consistent with the above physical process is that heating increases the near-cusp temperature until field lines there are forced open. The subsequent evacuation of the flux tubes by the newly forming slow wind decreases the temperature and heating until the flux tubes are able to reclose. Then, over a longer time scale, heating begins to again refill the flux tubes with plasma and increase the temperature until the cycle repeats itself. The calculations we report here are first steps towards quantitative evaluation of this scenario.

  13. Droplet evaporation on a soluble substrate

    NASA Astrophysics Data System (ADS)

    Mailleur, Alexandra; Pirat, Christophe; Colombani, Jean; CNES Collaboration

    2015-11-01

    Stains left by evaporated droplets are ubiquitous in everyday life as well as in industrial processes. Whatever the composition of the evaporating liquid (colloidal suspensions, biological fluids...), the stains are mostly constituted by a deposit at the periphery of the dried drop, similar to a coffee stain (Deegan, 1997). All these studies have been carried with non-reacting solids. In this presentation, we focus on the behavior of a pure-water droplet evaporating on a soluble substrate which is more complex, since three phenomena are strongly interacting: the dissolution of the substrate, the diffusion/convection of the dissolved species into the drop and the evaporation of the liquid. NaCl and KCl single crystals have been chosen for this experimental study as they are fast-dissolving solids. We have observed that the dissolution induces a pinning of the triple line from the beginning of the evaporation, leading to a decrease of the contact angle in time. At the end of the evaporation, a peripheral deposit is always formed, proof of an outward flow inside the drop (coffee-ring effect). The authors would like to thank the CNES for the financial support.

  14. SEWAGE DISPOSAL BY EVAPORATION-TRANSPIRATION

    EPA Science Inventory

    One of the methods for on-site disposal of wastewater from individual homes is by evaporation. Two types of evaporative disposal systems have been investigated in this study; evapo-transpiration (ET) beds and mechanical evaporation units. Twenty nine test lysimeters of 0.22 cubic...

  15. Orion Capsule Mockup is Dropped

    NASA Video Gallery

    An Orion capsule mockup is dropped from a plane 25,000 feet above the Arizona desert to test its parachute design. Orion will return to Earth at speeds faster than previous human spacecraft, and wi...

  16. Evaluation of a locally homogeneous model of spray evaporation

    NASA Technical Reports Server (NTRS)

    Shearer, A. J.; Faeth, G. M.

    1979-01-01

    A model of spray evaporation which employs a second-order turbulence model in conjunction with the locally homogeneous flow approximation, which implies infinitely fast interphase transport rates is presented. Measurements to test the model were completed for single phase constant and variable density jets, as well as an evaporating spray in stagnant air. Profiles of mean velocity, composition, temperature and drop size distribution as well as velocity fluctuations and Reynolds stress, were measured within the spray. Predictions were in agreement with measurements in single phase flows and also with many characteristics of the spray, e.g. flow width, radial profiles of mean and turbulent quantities, and the axial rate of decay of mean velocity and mixture fraction.

  17. Dilating Eye Drops

    MedlinePlus

    ... Frequently Asked Questions Español Condiciones Chinese Conditions Dilating Eye Drops En Español Read in Chinese What are dilating eye drops? Dilating eye drops contain medication to enlarge ( ...

  18. Evaporation control research, 1959-60

    USGS Publications Warehouse

    U.S. Geological Survey

    1963-01-01

    Two hundred and forty-five dispersions of long-chain alkanols were formulated by using various emulsifiers and alkanols. The dispensing and spreading ability of each of these formulations was tested. The most promising emulsifier that could be used with any of the alkanols was glyceryl monostearate (self-emulsifying). However, the concentration of the alkanol in the dispersion form varied somewhat: with the length of the carbon chain. A maximum concentration of 16 percent was obtained using the longer chain alkanols in the dispersion form without losing any of the properties of a fluid. Nine field tests were undertaken on small stock tanks. The retardant materials used in these tests were dodecanol, hexadecanol, and octadecanol. These materials were applied in either liquid or dispersion form. Four types of dispensing equipment were tested. The first type used a pressure system which sprayed a liquid onto the surface of the water. An anemometer and wind-controlled vane, operated by an electrical system, determined the length End frequency of application. The second type was similar to the first except that gravity was utilized to force the liquid onto the surface. The third type. used a drip system with rates of about 10 drops per minute. The fourth type used a gravity feed and a wind-controlled valve which allowed the dispersion material to flow onto the surface of the water when the wind was in the proper direction. In the field tests, the best reduction in evaporation was obtained using octadecanol in dispersion form and dispensed with the wind-controlled valve and gravity feed system. The maximum reduction in evaporation for a 2-week period was 27 percent. However, the economics of suppressing evaporation from stock tanks is questionable because of the short travel time across the tank by the film. There are still many problems unsolved. Some of these can be resolved in the laboratory whereas others can be resolved only in the field. Some of the more serious

  19. Instabilities of volatile films and drops

    NASA Astrophysics Data System (ADS)

    Murisic, Nebojsa

    2008-12-01

    We report on instabilities during spreading of volatile liquids, with emphasis on the novel instability observed when isopropyl alcohol (IPA) is deposited on a monocrystalline silicon (Si) wafer. This instability is characterized by emission of drops ahead of the expanding front, with each drop followed by smaller, satellite droplets, forming the structures which we nickname "octopi" due to their appearance. A less volatile liquid, or a substrate of larger heat conductivity, suppress this instability. In addition, we examine the spreading of drops of water (DIW)-IPA mixtures on both Si wafers and plain glass slides, and describe the variety of contact line instabilities which appear. We find that the decrease of IPA concentration in mixtures leads to transition from "octopi" to mushroom-like instabilities. Through manipulation of our experimental set up, we also find that the mechanism responsible for these instabilities appears to be mostly insensitive to both the external application of convection to the gas phase, and the doping of the gas phase with vapor in order to create the saturated environment. In order to better understand the "octopi" instability, we develop a theoretical model for evaporation of a pure liquid drop on a thermally conductive solid substrate. This model includes all relevant physical effects, including evaporation, thermal conductivity in both liquid and solid, (thermocapillary) Marangoni effect, vapor recoil, disjoining pressure, and gravity. The crucial ingredient in this problem is the evaporation model, since it influences both the motion of the drop contact line, and the temperature profiles along the liquid-solid and liquid-gas interfaces. We consider two evaporation models: the equilibrium "lens" model and the non-equilibrium one-sided (NEOS) model. Along with the assumption of equilibrium at the liquid-gas interface, the "lens" model also assumes that evaporation proceeds in a (vapor) diffusion-limited regime, therefore bringing

  20. Electrochemistry in an acoustically levitated drop.

    PubMed

    Chainani, Edward T; Ngo, Khanh T; Scheeline, Alexander

    2013-02-19

    Levitated drops show potential as microreactors, especially when radicals are present as reactants or products. Solid/liquid interfaces are absent or minimized, avoiding adsorption and interfacial reaction of conventional microfluidics. We report amperometric detection in an acoustically levitated drop with simultaneous ballistic addition of reactant. A gold microelectrode sensor was fabricated with a lithographic process; active electrode area was defined by a photosensitive polyimide mask. The microdisk gold working electrode of radius 19 μm was characterized using ferrocenemethanol in aqueous buffer. Using cyclic voltammetry, the electrochemically active surface area was estimated by combining a recessed microdisk electrode model with the Randles-Sevcik equation. Computer-controlled ballistic introduction of reactant droplets into the levitated drop was developed. Chronoamperometric measurements of ferrocyanide added ballistically demonstrate electrochemical monitoring using the microfabricated electrode in a levitated drop. Although concentration increases with time due to drop evaporation, the extent of concentration is predictable with a linear evaporation model. Comparison of diffusion-limited currents in pendant and levitated drops show that convection arising from acoustic levitation causes an enhancement of diffusion-limited current on the order of 16%. PMID:23351154

  1. Controlling Vapor Pressure In Hanging-Drop Crystallization

    NASA Technical Reports Server (NTRS)

    Carter, Daniel C.; Smith, Robbie

    1988-01-01

    Rate of evaporation adjusted to produce larger crystals. Device helps to control vapor pressure of water and other solvents in vicinity of hanging drop of solution containing dissolved enzyme protein. Well of porous frit (sintered glass) holds solution in proximity to drop of solution containing protein or enzyme. Vapor from solution in frit controls evaporation of solvent from drop to control precipitation of protein or enzyme. With device, rate of nucleation limited to decrease number and increase size (and perhaps quality) of crystals - large crystals of higher quality needed for x-ray diffraction studies of macromolecules.

  2. Ball feeder for replenishing evaporator feed

    DOEpatents

    Felde, D.K.; McKoon, R.H.

    1993-03-23

    Vapor source material such as uranium, which is to be dropped into a melt in an evaporator, is made into many balls of identical diameters and placed inside a container. An elongated sloping pipe is connected to the container and leads to the evaporator such that these balls can travel sequentially therealong by gravity. A metering valve in this pipe for passing these balls one at a time is opened in response to a signal when it is ascertained by a detector that there is a ball ready to be passed. A gate in the pipe near the evaporator momentarily stops the motion of the traveling ball and is then opened to allow the ball drop into the melt at a reduced speed.

  3. Ball feeder for replenishing evaporator feed

    DOEpatents

    Felde, David K.; McKoon, Robert H.

    1993-01-01

    Vapor source material such as uranium, which is to be dropped into a melt in an evaporator, is made into many balls of identical diameters and placed inside a container. An elongated sloping pipe is connected to the container and leads to the evaporator such that these balls can travel sequentially therealong by gravity. A metering valve in this pipe for passing these balls one at a time is opened in response to a signal when it is ascertained by a detector that there is a ball ready to be passed. A gate in the pipe near the evaporator momentarily stops the motion of the traveling ball and is then opened to allow the ball drop into the melt at a reduced speed.

  4. Polycrystalline lead iodide films produced by solution evaporation and tested in the mammography X-ray energy range

    NASA Astrophysics Data System (ADS)

    Condeles, J. F.; Mulato, M.

    2016-02-01

    Lead iodide polycrystalline films have been deposited on corning glass substrates using solution evaporation in oven. Films 6 μm-thick were obtained with full coverage of the substrates as verified by scanning electron microscopy. Some pin-holes were observable. X-ray diffraction revealed a crystalline structure corresponding to the 4 H-PbI2 polytype formation. Polarized Raman scattering experiments indicated a lamellar structure. Anisotropy was also investigated using depolarization ratio calculations. The optical and electrical properties of the samples were investigated using photoluminescence and dark conductivity as a function of temperature, respectively. Activation energies of 0.10 up to 0.89 eV were related to two main electrical transport mechanisms. Films were also exposed to X-ray irradiation in the mammography X-ray energy range. The detector produced was also exposed to X-ray from 5 mR up to 1450 mR. A linear response was observed as a function of dose with a slope of 0.52 nA/mm2 per mR.

  5. Dropping the Devil's Advocate: One Novice Language Tester's Shifting Interactional Practices across a Series of Speaking Tests

    ERIC Educational Resources Information Center

    Leyland, Christopher; Greer, Tim; Rettig-Miki, Ellen

    2016-01-01

    This study employs longitudinal Conversation Analysis (CA) to examine one TA's follow-up contributions in a series of EFL group discussion tests. By tracking the TA's interactional practices across 18 groups, we observe how she adapts her turn design by increasingly aligning towards that of the novice English speakers. The TA initially attempts to…

  6. Flash evaporation from turbulent water jets

    NASA Astrophysics Data System (ADS)

    Bharathan, D.; Penney, T.

    1983-02-01

    Results of an experimental investigation of flash evaporation from turbulent planar and axisymmetric water jets are reported. In the range of jet thicknesses tested, for planar jets, due to shattering, evaporation is found to be nearly independent of the jet thickness. Evaporation from the planar jets was found to be dependent on the initial level of turbulence in the water supply manifold. An approximate analysis to model the evaporation process based on the physical phenomena and experimental observations is outlined. Comparisons between the experimental data and analytical predictions of the liquid temperature variation along the jet are included. Use of screens in the water jet are shown to be effective for enhancing evaporation.

  7. A theoretical and experimental study of turbulent evaporating sprays

    NASA Technical Reports Server (NTRS)

    Solomon, A. S. P.; Shuen, J. S.; Zhang, Q. F.; Faeth, G. M.

    1984-01-01

    Measurements and analysis limited to the dilute portions of turbulent evaporating sprays, injected into a still air environment were completed. Mean and fluctuating velocities and Reynolds stress were measured in the continuous phase. Liquid phase measurements included liquid mass fluxes, drop sizes and drop size and velocity correlation. Initial conditions needed for model evaluation were measured at a location as close to the injector exit as possible. The test sprays showed significant effects of slip and turbulent dispersion of the discrete phase. The measurements were used to evaluate three typical models of these processes: (1) a locally homogeneous flow (LHF) model, where slip between the phases were neglected; (2) a deterministic separated flow (DSF) model, where slip was considered but effects of drop dispersion by turbulence were ignored; and (3) a stochastic separated flow (SSF) model, where effects of interphase slip and turbulent dispersion were considered using random-walk computations for drop motion. For all three models, a k-epsilon model as used to find the properties of the continuous phase. The LHF and DSF models did not provide very satisfactory predictions for the present measurements. In contrast, the SSF model performed reasonably well--with no modifications in the prescription of eddy properties from its original calibration.

  8. Alternate drop pulse polarography

    USGS Publications Warehouse

    Christie, J.H.; Jackson, L.L.; Osteryoung, R.A.

    1976-01-01

    The new technique of alternate drop pulse polarography is presented. An experimental evaluation of alternate drop pulse polarography shows complete compensation of the capacitative background due to drop expansion. The capillary response phenomenon was studied in the absence of faradaic reaction and the capillary response current was found to depend on the pulse width to the -0.72 power. Increased signal-to-noise ratios were obtained using alternate drop pulse polarography at shorter drop times.

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

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    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.

  10. Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.; Almlie, Jay C.

    2010-01-01

    A water membrane evaporator (WME) has been conceived and tested as an alternative to the contamination-sensitive and corrosion-prone evaporators currently used for dissipating heat from space vehicles. The WME consists mainly of the following components: An outer stainless-steel screen that provides structural support for the components mentioned next; Inside and in contact with the stainless-steel screen, a hydrophobic membrane that is permeable to water vapor; Inside and in contact with the hydrophobic membrane, a hydrophilic membrane that transports the liquid feedwater to the inner surface of the hydrophobic membrane; Inside and in contact with the hydrophilic membrane, an annular array of tubes through which flows the spacecraft coolant carrying the heat to be dissipated; and An inner exclusion tube that limits the volume of feedwater in the WME. In operation, a pressurized feedwater reservoir is connected to the volume between the exclusion tube and the coolant tubes. Feedwater fills the volume, saturates the hydrophilic membrane, and is retained by the hydrophobic membrane. The outside of the WME is exposed to space vacuum. Heat from the spacecraft coolant is conducted through the tube walls and the water-saturated hydrophilic membrane to the liquid/vapor interface at the hydrophobic membrane, causing water to evaporate to space. Makeup water flows into the hydrophilic membrane through gaps between the coolant tubes.

  11. Treatment of digestate from a co-digestion biogas plant by means of vacuum evaporation: tests for process optimization and environmental sustainability.

    PubMed

    Chiumenti, A; da Borso, F; Chiumenti, R; Teri, F; Segantin, P

    2013-06-01

    Vacuum evaporation consists in the boiling of a liquid substrate at negative pressure, at a temperature lower than typical boiling temperature at atmospheric conditions. Condensed vapor represents the so called condensate, while the remaining substrate represents the concentrate. This technology is derived from other sectors and is mainly dedicated to the recovery of chemicals from industrial by-products, while it has not been widely implemented yet in the field of agricultural digestate treatment. The present paper relates on experimental tests performed in pilot-scale vacuum evaporation plants (0.100 and 0.025 m(3)), treating filtered digestate (liquid fraction of digestate filtered by a screw-press separator). Digestate was produced by a 1 MWe anaerobic digestion plant fed with swine manure, corn silage and other biomasses. Different system and process configurations were tested (single-stage and two-stage, with and without acidification) with the main objectives of assessing the technical feasibility and of optimizing process parameters for an eventual technology transfer to full scale systems. The inputs and outputs of the process were subject to characterization and mass and nutrients balances were determined. The vacuum evaporation process determined a relevant mass reduction of digestate. The single stage configuration determined the production of a concentrate, still in liquid phase, with a total solid (TS) mean concentration of 15.0%, representing, in terms of mass, 20.2% of the input; the remaining 79.8% was represented by condensate. The introduction of the second stage allowed to obtain a solid concentrate, characterized by a content of TS of 59.0% and representing 5.6% of initial mass. Nitrogen balance was influenced by digestate pH: in order to limit the stripping of ammonia and its transfer to condensate it was necessary to reduce the pH. At pH 5, 97.5% of total nitrogen remained in the concentrate. This product was characterized by very high

  12. Blood drop patterns: Formation and applications.

    PubMed

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

    2016-05-01

    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. PMID:26988066

  13. Fragmentation of hot classical drops

    SciTech Connect

    Vicentini, A.; Jacucci, G.; Pandharipande, V.R.

    1985-05-01

    Time evolution of hot drops of matter containing approx.230 or approx.130 particles is studied by classical molecular dynamics. Initially, the drops have uniform density and a sharp surface. The chosen initial conditions include three values of density and a range of temperatures wide enough to study the phenomena of evaporation, fragmentation, and total vaporization in a unified fashion. The average density and temperature of central matter is measured periodically to obtain trajectories of the evolution in the rho,T plane. These trajectories indicate that the matter expands almost adiabatically until it reaches the region of adiabatic instabilities. Density inhomogeneities develop in this region, but the matter fragments only if the expansion continues to average densities of less than one-fourth the liquid density, otherwise it recondenses into a single blob. The recondensed matter and fragments have very crooked surfaces. If the temperature is high enough, the expanding matter does not enter the region of adiabatic instabilities and totally vaporizes. For initial densities of the order of equilibrium density, matter does not fragment or develop large inhomogeneities in the region enclosed by the isothermal and adiabatic spinodals. Thus it appears unlikely that fragmentation of small drops (nuclei) can be used to study the isothermal critical region of gas-liquid phase transition. A detailed tabulation of the energies and number of monomers, dimers, light, and heavy fragments emitted in each event is presented.

  14. 242-A Evaporator/plutonium uranium extraction (PUREX) effluent treatment facility (ETF) nonradioactive air emission test report

    SciTech Connect

    Hill, J.S., Westinghouse Hanford

    1996-05-10

    This report shows the methods used to test the stack gas outlet concentration and emission rate of Volatile Organic Compounds as Total Non-Methane Hydrocarbons in parts per million by volume,grams per dry standard cubic meter, and grams per minute from the PUREX ETF stream number G6 on the Hanford Site. Test results are shown in Appendix B.1.

  15. Effects of Specimen Thickness and Notch Shape on Fracture Modes in the Drop Weight Tear Test of API X70 and X80 Linepipe Steels

    NASA Astrophysics Data System (ADS)

    Hong, Seokmin; Shin, Sang Yong; Lee, Sunghak; Kim, Nack J.

    2011-09-01

    This study is concerned with effects of specimen thickness and notch shape on drop weight tear test (DWTT) properties and fracture modes of API X70 and API X80 low-carbon microalloyed linepipe steels. Detailed fractographic analysis of broken DWTT specimens showed that the fracture initiated in an initial cleavage mode near the specimen notch and that some delaminations occurred at the center of the fracture surface. The chevron notch (CN) DWTT specimens had broader initial cleavage areas than the pressed notch (PN) DWTT specimens. The larger inverse fracture areas ( i.e., cleavage areas close the hammer impact side) appeared in the PN DWTT specimens, because their higher fracture initiation energy at the notch allowed a higher strain hardening in the hammer-impacted region. The number and length of delaminations were larger in the CN DWTT specimens than in the PN DWTT specimens, and increased with increasing specimen thickness due to the plane strain condition effect. As the test temperature decreased, the tendency of delaminations increased, but delaminations were not found when the cleavage fracture prevailed at very low temperatures. The DWTT test results such as upper shelf energy (USE) and energy transition temperature (ETT) were discussed with relation to microstructures and fracture modes including initial cleavage fracture, ductile fracture, inverse fracture, and delaminations.

  16. Effects of Dynamic Strain Hardening Exponent on Abnormal Cleavage Fracture Occurring During Drop Weight Tear Test of API X70 and X80 Linepipe Steels

    NASA Astrophysics Data System (ADS)

    Kang, Minju; Kim, Hyunmin; Lee, Sunghak; Shin, Sang Yong

    2014-02-01

    In this study, drop weight tear tests (DWTT) were conducted on API X70 and X80 linepipe steels fabricated with various compositions and rolling and cooling conditions in order to correlate the strain hardening with the abnormal cleavage fracture occurring in the hammer-impacted area. Area fractions of fracture modes were measured from fractured DWTT specimens, and the measured data were analyzed in relation to microstructures, Charpy impact energy, and strain hardening. All the steels consisted of fine acicular ferrite, together with some bainitic ferrite, granular bainite, and martensite-austenite constituent. As the volume fraction of acicular ferrite increased, the area fraction of DWTT abnormal cleavage fracture decreased because the toughness of acicular ferrite was higher than other microstructures. The area fraction of abnormal cleavage fracture was weakly related with strain hardening exponents obtained from the quasi-static tensile and compressive tests, but showed better correlation with those obtained from the dynamic compressive test. This tendency could be more clearly observed when steels having similar Charpy impact energy levels were grouped. Since the DWTT was performed under a dynamic loading condition, thus, the abnormal cleavage fracture behavior should be related with the strain hardening analyzed under a dynamic loading condition.

  17. Evaluation of a locally homogeneous model of spray evaporation

    NASA Technical Reports Server (NTRS)

    Shearer, A. J.; Faeth, G. M.; Tamura, H.

    1978-01-01

    Measurements were conducted on an evaporating spray in a stagnant environment. The spray was formed using an air-atomizing injector to yield a Sauter mean diameter of the order of 30 microns. The region where evaporation occurred extended approximately 1 m from the injector for the test conditions. Profiles of mean velocity, temperature, composition, and drop size distribution, as well as velocity fluctuations and Reynolds stress, were measured. The results are compared with a locally homogeneous two-phase flow model which implies no velocity difference and thermodynamic equilibrium between the phases. The flow was represented by a k-epsilon-g turbulence model employing a clipped Gaussian probability density function for mixture fraction fluctuations. The model provides a good representation of earlier single-phase jet measurements, but generally overestimates the rate of development of the spray. Using the model predictions to represent conditions along the centerline of the spray, drop life-history calculations were conducted which indicate that these discrepancies are due to slip and loss of thermodynamic equilibrium between the phases.

  18. Attracting Water Drops

    NASA Video Gallery

    Astronauts Cady Coleman and Ron Garan perform the Attracting Water Drops experiment from Chabad Hebrew Academy in San Diego, Calif. This research determines if a free-floating water drop can be att...

  19. Dilating Eye Drops

    MedlinePlus

    ... Conditions Most Common Searches Adult Strabismus Amblyopia Cataract Conjunctivitis Corneal Abrasions Dilating Eye Drops Lazy eye (defined) ... Loading... Most Common Searches Adult Strabismus Amblyopia Cataract Conjunctivitis Corneal Abrasions Dilating Eye Drops Lazy eye (defined) ...

  20. Ternary drop collisions

    NASA Astrophysics Data System (ADS)

    Hinterbichler, Hannes; Planchette, Carole; Brenn, Günter

    2015-10-01

    It has been recently proposed to use drop collisions for producing advanced particles or well-defined capsules, or to perform chemical reactions where the merged drops constitute a micro-reactor. For all these promising applications, it is essential to determine whether the merged drops remain stable after the collision, forming a single entity, or if they break up. This topic, widely investigated for binary drop collisions of miscible and immiscible liquid, is quite unexplored for ternary drop collisions. The current study aims to close this gap by experimentally investigating collisions between three equal-sized drops of the same liquid arranged centri-symmetrically. Three drop generators are simultaneously operated to obtain controlled ternary drop collisions. The collision outcomes are observed via photographs and compared to those of binary collisions. Similar to binary collisions, a regime map is built, showing coalescence and bouncing as well as reflexive and stretching separation. Significant differences are observed in the transitions between these regimes.

  1. Laser precipitation monitor for measurement of drop size and velocity of moving spray-plate sprinklers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sprinkler drop size distribution and associated drop velocities have a major influence on sprinkler performance in regards to application intensity, uniformity of water application, wind drift, evaporation losses and kinetic energy transferred to the soil surface. Sprinkler drop size measurements a...

  2. Vapor compression evaporator concentrates, recovers alcohol

    SciTech Connect

    Miller, M.N.; Robe, K.; Bacchetti, J.A.

    1982-11-01

    This article focuses on presenting a solution to the high energy cost of operating a steam heated, single effect evaporator used by Monsanto Industrial Chemical Company at a plant in Seattle, Wash., to produce vanillin from pulp and paper mill sulfite. Use of the single effect flash evaporator resulted in high energy usage due not only to the ''single effect'' use of steam, but also because energy consumption was reduced only slightly at low operating rates. The solution to this problem was the replacement of the single effect evaporator with a vapor recompression evaporator. Operating for over 1 1/2 years, the vapor recompression evaporator system has had no significant maintenance problems. The system operates with only 1/60th the steam consumption and 15% of the total energy consumption of the previous evaporator and has had no tube fouling. Also, since the distillate is condensed within the evaporator, less cooling water is required, allowing two heat exchangers to be taken out of service. When operating at less than design capacity, the energy consumption drops almost linearly with the feed rate. At low feed rates, a by-pass valve unloads the compressor to reduce energy consumption. Total energy consumption, now 15% of the previous level, results in an estimated pay-back of less than three years.

  3. Standard test method for water in lint cotton by oven evaporation combined with volumetric Karl Fischer Titration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The referenced test method for total water content and water regain in lint cotton was developed by USDA scientists in New Orleans at the request of the cotton industry. The method covers the determination of the total water (free and bound) in raw and lint cotton at moisture equilibrium from con...

  4. The effects of lubricant eye drops on visual function as measured by the Inter-blink interval Visual Acuity Decay test

    PubMed Central

    Torkildsen, Gail

    2009-01-01

    Objective: The purpose of the current study was to evaluate the effects of two marketed ocular lubricants on the visual decay in dry eye patients using the Inter-blink interval Visual Acuity Decay (IVAD) test. Methods: This controlled, randomized, double-masked crossover study compared the effects of a polyethylene glycol/propylene glycol-based (PEG/PG) tear and a carboxymethylcellulose sodium (CMC)/glycerin tear on the visual acuity decay between blinks of dry eye patients. At visit 1 (Day 0), baseline IVAD measurements were recorded prior to instillation of a single drop of randomized study medication. IVAD testing was repeated at 15-, 45-, and 90-minutes post-instillation. Reading rate and functional blink rate were also evaluated. At the second visit (Day 7 ± 3), study procedures were repeated using crossover treatment. Results: Forty-eight (48) subjects with dry eye (61.1 ± 14.8 years old, 79.2% female, 95.8% white) completed the study. Treatment with the PEG/PG-based tear demonstrated statistically significantly longer time to one-line loss of best-corrected visual acuity (BCVA) as determined by the IVAD test at 90 minutes post-instillation compared to the CMC/glycerin tear (P = 0.0365). Measurements of median time at BCVA, reading rate, and functional blink rate were similar for both treatments. Both formulations were well tolerated in the population studied. Conclusions: Treatment with the PEG/PG-based tear demonstrated statistically significant improved maintenance of visual acuity between blinks at 90 minutes post-instillation compared to the CMC/glycerin tear. This is the first study to demonstrate the ability of an artificial tear to extend visual acuity maintenance between blinks, as measured by the IVAD test. PMID:19789659

  5. Evaporative heat transfer and enhancement performance of serpentine tubes with strip-type inserts using refrigerant-134a

    SciTech Connect

    Hsieh, S.S.; Jang, K.J.; Huang, M.T.

    1999-08-01

    Recent technological implications have given rise to increased interest in enhancement of the in-tube evaporation used in many air conditioning and refrigeration systems. Although many past studies have examined in-tube evaporative heat transfer enhancement and the associated pressure drop with internally finned tubes, in-tube evaporations with strip-type inserts, using R-134a as a refrigerant, have not been conducted. In addition, the fundamental phenomenon of nucleate boiling from a heated wall subject to a strip-type insert is as yet not well understood, especially for the flow in serpentine tubes. In this study, flow boiling tests were conducted in serpentine coil with inserts. To accomplish these tasks, experiments were performed in a seven-pass serpentine test tube with longitudinal strip and cross-strip types inserts, 10.6-mm inside diameter with R-134a as the boiling fluid immersed in a hot water bath.

  6. Load and dynamic assessment of B-52B-008 carrier aircraft for finned configuration 1 space shuttle solid rocket booster decelerator subsystem drop test vehicle. Volume 2: Airplane flutter and load analysis results

    NASA Technical Reports Server (NTRS)

    Quade, D. A.

    1978-01-01

    The airplane flutter and maneuver-gust load analysis results obtained during B-52B drop test vehicle configuration (with fins) evaluation are presented. These data are presented as supplementary data to that given in Volume 1 of this document. A brief mathematical description of airspeed notation and gust load factor criteria are provided as a help to the user. References are defined which provide mathematical description of the airplane flutter and load analysis techniques. Air-speed-load factor diagrams are provided for the airplane weight configurations reanalyzed for finned drop test vehicle configuration.

  7. Load and dynamic assessment of B-52B-008 carrier aircraft for finned configuration 1 space shuttle solid rocket booster deceleration subsystem drop test vehicle. Volume 4: Pylon load data

    NASA Technical Reports Server (NTRS)

    Quade, D. A.

    1978-01-01

    The pylon loading at the drop test vehicle and wing interface attack points is presented. The loads shown are determined using a stiffness method, which assumes the side stiffness of the forward hook guide and the fore and aft stiffness of each drag pin to be equal. The net effect of this assumption is that the forward hook guide reacts approximately 96% of the drop test vehicle yawing moment. For a comparison of these loads to previous X-15 analysis design loadings, see Volume 1 of this document.

  8. Load and dynamic assessment of B-52B-008 carrier aircraft for finned configuration 1 space shuttle solid rocket booster decelerator subsystem drop test vehicle. Volume 3: Pylon load data method 1

    NASA Technical Reports Server (NTRS)

    Quade, D. A.

    1978-01-01

    The pylon loading at the drop test vehicle and wing interface attach points is presented. The loads shown are determined using a stiffness method, which assumes the side stiffness of the foreward hook guide to be one-fourth of the fore and aft stiffness of each drag pin. The net effect of this assumption is that the forward hook guide reacts approximately 85% of the drop test vehicle yawing moment. For a comparison of these loads to previous X-15 analysis design loadings, see Volume 1 of this document.

  9. Evaporator Cleaning Studies

    SciTech Connect

    Wilmarth, W.R.

    1999-04-15

    Operation of the 242-16H High Level Waste Evaporator proves crucial to liquid waste management in the H-Area Tank Farm. Recent operational history of the Evaporator showed significant solid formation in secondary lines and in the evaporator pot. Additional samples remain necessary to ensure material identity in the evaporator pot. Analysis of these future samples will provide actinide partitioning information and dissolution characteristics of the solid material from the pot to ensure safe chemical cleaning.

  10. Exploratory tests of washing radioactive sludge samples from the Melton Valley and evaporator facility storage tanks at ORNL

    SciTech Connect

    Sears, M.B.; Botts, J.L.; Keller, J.M.

    1991-09-01

    Exploratory tests were initiated to wash radioactive sludge samples from the waste storage tanks at the Oak Ridge National Laboratory (ORNL). The purpose was to provide preliminary information about (1) the anions in the sludge phase that are soluble in water or dilute acid (e.g., the anions in the interstitial liquid) and (2) the solubilities of sludge constituents in water under process conditions. The experiments were terminated before completion due to changing priorities by the Department of Energy (DOE). This memorandum was prepared primarily for documentation purposes and presents the incomplete data. 3 refs., 13 tabs.

  11. Deformation and secondary breakup of drops

    NASA Astrophysics Data System (ADS)

    Hsiang, L.-P.; Faeth, G. M.

    1993-01-01

    Drop properties during and after secondary breakup in the bag, multimode and shear breakup regimes were observed for shock wave initiated disturbances in air at normal temperature and pressure. Test liquids included water, n-heptane, ethyl alcohol and glycerol mixtures to yield Weber numbers of 15-600. Ohnesorge numbers of 0.0025-0.039, liquid/gas density ratios of 579-985 and Reynolds numbers of 1060-15080. Measurements included pulsed shadowgraphy and double-pulsed holography to find drop sizes and velocities after breakup. Drop size distributions after breakup satisfied Simmons' universal root normal distribution in all three breakup regimes, after removing the core (or drop-forming) drop from the drop population for shear breakup. The size and velocity of the core drop after shear breakup then was correlated successfully based on the observation that the end of drop stripping corresponded to a constant Eotvos number. The relative velocities of the drop liquid were significantly reduced during secondary breakup, due both to large drag coefficients during the drop deformation stage and reduced relaxation times of smaller drops. These effects were correlated successfully based on a simplified phenomenological theory.

  12. Coffee Stains from Drops with Receding Contact Lines

    NASA Astrophysics Data System (ADS)

    Freed-Brown, Julian

    2015-03-01

    We present a framework for calculating the surface density profile of a coffee stain deposited by a drying drop with a receding contact line. For standard coffee stains, the fluid pins to the substrate, forces flow towards the exterior of the drop and deposits a thin, concentrated ring of particles. Unlike a pinned drop, a receding drop pushes fluid towards its interior and continuously deposits mass across its substrate as it evaporates. This gives rise to a new class of mountain-like morphologies that are not seen in the standard coffee ring effect but are reminiscent of recent experimental results. For a thin, circular drop with uniform evaporation, we calculate the surface density profile analytically and find that it diverges towards the center of the drop as η ~r - 1 / 2 , where r is the distance from the center. We estimate how this divergence is softened due to solute interactions at the final stage of drying. Our framework can easily be extended numerically or analytically to investigate novel stain morphologies left by drying drops of different shapes and evaporation profiles. This work is part of a thesis project advised by Tom Witten. It was supported in part by the National Science Foundation's MRSEC Program under Award Number DMR 0820054.

  13. Leidenfrost drops on liquid baths: theory

    NASA Astrophysics Data System (ADS)

    Sobac, Benjamin; Rednikov, Alexei; Maquet, Laurent; Darbois-Texier, Baptiste; Duchesne, Alexis; Brandenbourger, Martin; Dorbolo, Stéphane; Colinet, Pierre

    2015-11-01

    It is well known that a liquid drop released over a very hot surface generally does not contact the surface nor boils but rather levitates over a thin vapor film generated by its own evaporation (Leidenfrost effect). In particular, the case of a hot (and flat) solid substrate has been extensively studied in recent years. In contrast, we here focus on Leidenfrost drops over a superheated liquid bath, addressing the problem theoretically and comparing our predictions with experimental results, detailed in a separate talk. We predict the geometry of the drop and of the liquid bath, based on the hydrostatic Young-Laplace and lubrication equations. A good agreement is observed with the available experimental data concerning the deformation of the liquid bath. The modeling also yields a rather complete insight into the shape of the drop. As in the case of a solid substrate, the vapor layer generally appears to be composed of a vapor pocket surrounded by a circular neck. The influences of the superheat and of the drop size are parametrically investigated. A number of scaling laws are established. Unlike the case of a solid substrate, no chimney instability was found in the range of drop size studied.

  14. Getting the Drop on Sediment

    ERIC Educational Resources Information Center

    Galindez, Peter

    1977-01-01

    In this exercise, students examine Aristotle's weight hypothesis by testing variously shaped marble chips. These chips are weighed and dropped down a water tube. Average fall times and weights are recorded and graphed. Students are asked to apply this information to rock and soil deposition by streams. (MA)

  15. The evaluation of evaporation by infrared thermography: A critical analysis of the measurements on the Crau test site. [France

    NASA Technical Reports Server (NTRS)

    Seguin, B.; Petit, V.; Devillard, R.; Reich, P.; Thouy, G. (Principal Investigator)

    1980-01-01

    Evapotranspiration was calculated for both the dry and irrigated zone by four methods which were compared with the energy balance method serving as a reference. Two methods did not involve the surface temperature. They are ETR(n) = R(n), liable to be valid under wet conditions and ET(eq) = (delta/delta + gamma) R(n) i.e, the first term of Penman's equation, adapted to moderately dry conditions. The methods using surface temperature were the combined energy balance aerodynamic approach and a simplified approach proposed by Jackson et al. Tests show the surface temperature methods give relatively satisfactory results both in the dry and wet zone, with a precision of 10% to 15% compared with the reference method. As was to be expected, ET(eq) gave satisfactory results only in the dry zone and ET(Rn) in the irrigated zone. Thermography increased the precision in the estimate of ET relative to the most suitable classical method by 5% to 8% and is equally suitable for both dry and wet conditions. The Jackson method does not require extensive ground measurements and the evaluation of the surface roughness.

  16. Evaporation in space manufacturing

    NASA Technical Reports Server (NTRS)

    Li, C. H.

    1974-01-01

    'Normal evaporation' equations for predicting the compositional changes with time and temperature have been developed and correlated with actual experimental data. An evaporative congruent temperature is defined and used to explain, predict, or plan space experiments on anomalous constitutional melting (on cooling) or solidification (on heating). Uneven evaporation causes reactive jetting forces capable of initiating new convection currents, nongravitational accelerations, surface vibrations, or other disturbances. Applications of evaporation to space manufacturing are described concerning evaporative purification, surface cooling, specimen selection, particles splitting, freezing data interpretation, material loss and dimensional control, and surface contamination or compositional changes.

  17. Marangoni instability induced convection in an evaporating liquid droplet

    NASA Technical Reports Server (NTRS)

    Chai, An-Ti; Rashidnia, N.; Arpaci, V. S.

    1992-01-01

    The processes occurring when a liquid drop undergoes evaporation are described. When a liquid drop undergoes evaporation, its surface temperature decreases. If the droplet is free floating in a microgravity environment, the heat transfer process inside the droplet is initially condition controlled. As the process continues, a radial temperature gradient builds up at the free surface until the critical Marangoni number is exceeded. Then the onset of instability induces thermocapillary convective flows, which in turn speed up the evaporation. The convective flows will subside when the interior of the droplet reaches a certain equilibrium temperature, and the process will return to the diffusion controlled mode. Both preliminary modeling and recent laboratory data have confirmed that Marangoni instability induced convection can and does occur in the droplet evaporation process. Mathematical models representing Marangoni instability in an evaporating liquid drop are presented. An ideal space experiment to study and characterize the onset of Marangoni instability in an evaporating liquid droplet and to establish the effect of Marangoni instability induced convection on the droplet evaporation rate is outlined and the need for conducting such experiments in space is highlighted. However, before an opportunity to conduct experiments in space arises, ground based experiments have to be conducted to study feasibility issues and proof of concept. A ground based experiment of this type is outlined.

  18. Transient heat transfer from shrinking LOX-drop

    NASA Technical Reports Server (NTRS)

    Kondic, Nenad N.

    1988-01-01

    In order to achieve prescribed experimental conditions in wind tunnels, the nitrogen-oxygen mixture is enriched by injection of liquid oxygen (LOX) upstream of methane burners. The objective of the study is to determine the LOX drop evaporation rate, which is dominated by heat transfer from the air stream (mass transfer mechanism can be later coupled with the solution from the present work). Since the concentration of drops in the surrounding gas is quite high, the concept of infinite medium cannot be utilized. Drop evaporation, as part of system's mass balance, is an important source-term in the finite-difference 2/3-dimensional network terms of laboratory-system (Eulerian) coordinates, while individual drop behavior, including its thermal history, is analyzed in Lagrangian coordinates.

  19. Drag on Sessile Drops

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

  20. Leidenfrost effect: accurate drop shape modeling and new scaling laws

    NASA Astrophysics Data System (ADS)

    Sobac, Benjamin; Rednikov, Alexey; Dorbolo, Stéphane; Colinet, Pierre

    2014-11-01

    In this study, we theoretically investigate the shape of a drop in a Leidenfrost state, focusing on the geometry of the vapor layer. The drop geometry is modeled by numerically matching the solution of the hydrostatic shape of a superhydrophobic drop (for the upper part) with the solution of the lubrication equation of the vapor flow underlying the drop (for the bottom part). The results highlight that the vapor layer, fed by evaporation, forms a concave depression in the drop interface that becomes increasingly marked with the drop size. The vapor layer then consists of a gas pocket in the center and a thin annular neck surrounding it. The film thickness increases with the size of the drop, and the thickness at the neck appears to be of the order of 10--100 μm in the case of water. The model is compared to recent experimental results [Burton et al., Phys. Rev. Lett., 074301 (2012)] and shows an excellent agreement, without any fitting parameter. New scaling laws also emerge from this model. The geometry of the vapor pocket is only weakly dependent on the superheat (and thus on the evaporation rate), this weak dependence being more pronounced in the neck region. In turn, the vapor layer characteristics strongly depend on the drop size.

  1. Theoretical Basis for Estimated Test Times and Conditions for Drop Tower and Space-Based Droplet Burning Experiments With Methanol and N-Heptane

    NASA Technical Reports Server (NTRS)

    Marchese, Anthony J.; Dryer, Fredrick L.; Choi, Mun Y.

    1994-01-01

    In order to develop an extensive envelope of test conditions for NASA's space-based Droplet Combustion Experiment (DCE) as well those droplet experiments which can be performed using a drop tower, the transient vaporization and combustion of methanol and n-heptane droplets were simulated using a recently developed fully time-dependent, spherically symmetric droplet combustion model. The transient vaporization of methanol and n-heptane was modeled to characterize the instantaneous gas phase composition surrounding the droplet prior to the introduction of an ignition source. The results for methanol/air showed that the entire gas phase surrounding a 2 mm methanol droplet deployed in zero-g .quickly falls outside the lean flammability limit. The gas phase surrounding an identically-sized n-heptane droplet, on the other hand, remains flammable. The combustion of methanol was then modeled considering a detailed gas phase chemical kinetic mechanism (168 steps, 26 species) and the effect of the dissolution of flame-generated water into the liquid droplet. These results were used to determine the critical ignition diameter required to achieve quasi-steady droplet combustion in a given oxidizing environment. For droplet diameters greater than the critical ignition diameter, the model predicted a finite diameter at which the flame would extinguish. These extinction diameters were found to vary significantly with initial droplet diameter. This phenomenon appears to be unique to the transient heat transfer, mass transfer and chemical kinetics of the system and thus has not been reported elsewhere to date. The extinction diameter was also shown to vary significantly with the liquid phase Lewis number since the amount of water present in the droplet at extinction is largely governed by the rate at which water is transported into the droplet via mass diffusion. Finally, the numerical results for n-heptane combustion were obtained using both 2 step and 96 step semi

  2. PROCESS WATER BUILDING, TRA605. FLASH EVAPORATOR, CONDENSER (PROJECT FROM EVAPORATOR), ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PROCESS WATER BUILDING, TRA-605. FLASH EVAPORATOR, CONDENSER (PROJECT FROM EVAPORATOR), AND STEAM EJECTOR (ALONG REAR WALL). INL NEGATIVE NO. 4377. M.H. Bartz, Photographer, 3/5/1952 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  3. Aging, Terminal Decline, and Terminal Drop

    ERIC Educational Resources Information Center

    Palmore, Erdman; Cleveland, William

    1976-01-01

    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)

  4. Strength of self-pinning in coffee drops

    NASA Astrophysics Data System (ADS)

    Latka, Andrzej; Kawczinski, Kimberly; Nagel, Sidney

    The equilibrium contact angle θe of a liquid drop placed on a solid surface is uniquely determined by a balance of surface tension forces according to Young's Equation, yet is rarely observed in real systems. Due to contact angle hysteresis, liquids can make contact with a surface at any angle between the receding and advancing contact angle: θR <θe <θA . A particularly striking example of this phenomenon is the familiar coffee stain. For coffee θR = 0 , thus as the drop evaporates the contact line remains pinned at its initial location. This results in the majority of the coffee being deposited in a characteristic ring at the drop's original boundary. We investigate how solid particles suspended in a liquid could so strongly influence contact angle hysteresis, by measuring the receding contact angle of a drop at various times during the evaporation process. For low solute concentrations, θR slowly decreases as the drop evaporates, but remains positive. Surprisingly, we find that increasing the solute concentration results in θR = 0 and a fully pinned contact line almost immediately after the drop is deposited.

  5. Youth Crime Drop. Report.

    ERIC Educational Resources Information Center

    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…

  6. Axisymmetric Liquid Hanging Drops

    ERIC Educational Resources Information Center

    Meister, Erich C.; Latychevskaia, Tatiana Yu

    2006-01-01

    The geometry of drops hanging on a circular capillary can be determined by numerically solving a dimensionless differential equation that is independent on any material properties, which enables one to follow the change of the height, surface area, and contact angle of drops hanging on a particular capillary. The results show that the application…

  7. Drop Tower Physics

    ERIC Educational Resources Information Center

    Dittrich, William A.

    2014-01-01

    The drop towers of yesteryear were used to make lead shot for muskets, as described in "The Physics Teacher" 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…

  8. Micromachined evaporators for AMTEC cells

    SciTech Connect

    Izenson, M.G.; Crowley, C.J.

    1996-12-31

    To achieve high cell efficiency and reliability, the capillary pumping system for Alkali Metal Thermal to Electric Conversion (AMTEC) must have three key characteristics: (1) very small pores to achieve a high capillary pumping head, (2) high permeability for the flow of liquid sodium to minimize internal losses, and (3) be made from a material that is exceptionally stable at high temperatures in a sodium environment. The authors have developed micromachining techniques to manufacture high performance evaporators for AMTEC cells. The evaporators have been fabricated from stainless steel, molybdenum, and a niobium alloy (Nb-1Zr). The regular, micromachined structure leads to very high capillary pumping head with high permeability for liquid flow. Data from tests performed with common fluids at room temperature characterize the capillary pumping head and permeability of these structures. Three micromachined evaporators have been built into AMTEC cells and operated at temperatures up to 1,100 K. Results from these tests confirm the excellent pumping capabilities of the micromachined evaporators.

  9. Algorithms for fast axisymmetric drop shape analysis measurements by a charge coupled device video camera and simulation procedure for test and evaluation

    NASA Astrophysics Data System (ADS)

    Busoni, Lorenzo; Carlà, Marcello; Lanzi, Leonardo

    2001-06-01

    A set of fast algorithms for axisymmetric drop shape analysis measurements is described. Speed has been improved by more than 1 order of magnitude over previously available procedures. Frame analysis is performed and drop characteristics and interfacial tension γ are computed in less than 40 ms on a Pentium III 450 MHz PC, while preserving an overall accuracy in Δγ/γ close to 1×10-4. A new procedure is described to evaluate both the algorithms performance and the contribution of each source of experimental error to the overall measurement accuracy.

  10. Detailed characteristics of drop-laden mixing layers: LES predictions compared to DNS

    NASA Technical Reports Server (NTRS)

    Okong'o, N.; Leboissetier, A.; Bellan, J.

    2004-01-01

    Results have been compared from Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES) of a temporal mixing layer laden with evaporating drops, to assess the ability of LES to reproduce detailed characteristics of DNS.

  11. DNSs of Multicomponent Gaseous and Drop-Laden Mixing Layers Achieving Transition to Turbulence

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Selle, Laurent

    2007-01-01

    A paper describes direct numerical simulations (DNSs) of three-dimensional mixing-layer flows undergoing transition to turbulence; the mixing layers may or may not be laden with evaporating liquid drops.

  12. Transport of Colloids along Corners: Visualization of Evaporation-Induced Flows beyond the Axisymmetric Condition.

    PubMed

    Vélez-Cordero, J Rodrigo; Yáñez Soto, Bernardo; Arauz-Lara, José L

    2016-08-16

    Nonhomogeneous evaporation fluxes have been shown to promote the formation of internal currents in sessile droplets, explaining the patterns that suspended particles leave after the droplet has dried out. Although most evaporation experiments have been conducted using spherical-cap-shaped drops, which are essentially in an axisymmetric geometry, here we show an example of nonhomogeneous evaporation in asymmetric geometries, which is visualized by following the motion of colloidal particles along liquid fingers forming a meniscus at square corners. It is found that the particle's velocity increases with the diffusive evaporation factor [Formula: see text] for the three tested fluids: water, isopropyl alcohol (IPA), and ethanol (EtOH). Here, [Formula: see text] is the vapor diffusivity in air, RH is the relative amount of vapor in the atmosphere, and cs is the saturated vapor concentration. We observed that in IPA and EtOH the internal currents promote a 3D spiral motion, whereas in water the particle's trajectory is basically unidirectional. By adding 0.25 critical micelle concentration (CMC) of sodium dodecyl sulfate (SDS) surfactant in water, a velocity blast was observed in the whole circulation flow pattern, going from [Formula: see text] to nearly [Formula: see text] in the longitudinal velocity component. To assess the effect of breaking the axisymmetric condition on the evaporation flux profile, we numerically solved the diffusive equation in model geometries that preserve the value of the contact angle θ but introduce an additional angle ϕ that characterizes the solid substrate. By testing different combinations of θ and ϕ, we corroborated that the evaporation flux increases when the substrate and the gas-liquid curves meet at corners with increasing sharpness. PMID:27437865

  13. Drop impact of suspensions

    NASA Astrophysics Data System (ADS)

    Thoraval, M.-J.; Boyer, F.; Sandoval Nava, E.; Dijksman, J. F.; Lohse, D.; Snoeijer, J. H.

    2014-11-01

    Drop impact studies have a wide range of applications, many of which involve complex fluids. We study here the liquid drop impact of a silver nano-particles dispersion on a solid glass surface. This dispersion is used for inkjet printing of functional electronic materials. When the impact velocity increases, the drop classically splashes into smaller droplets. However, it surprisingly stops splashing above a critical impact velocity. We combine high-speed imaging experiments with different characterizations of the dispersion to understand this transition to non-splashing.

  14. Measure Guideline: Evaporative Condensers

    SciTech Connect

    German, A; Dakin, B.; Hoeschele, M.

    2012-03-01

    This measure guideline on evaporative condensers provides information on properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices.

  15. Evaporation, Boiling and Bubbles

    ERIC Educational Resources Information Center

    Goodwin, Alan

    2012-01-01

    Evaporation and boiling are both terms applied to the change of a liquid to the vapour/gaseous state. This article argues that it is the formation of bubbles of vapour within the liquid that most clearly differentiates boiling from evaporation although only a minority of chemistry textbooks seems to mention bubble formation in this context. The…

  16. Mia Mikre Stagona (The Little Drop of Water).

    ERIC Educational Resources Information Center

    Palandra, Maria; Spiridakis, Eugenia

    This Greek reader for children in kindergarten and first grade is about a drop of water that comes to life in a trip through the water cycle of evaporation, condensation, and subsequent return to a drier part of the earth's surface environment. The story is suitable for reading aloud or independent reading. The text is entirely in Greek.…

  17. La Gotita de Agua (The Little Drop of Water).

    ERIC Educational Resources Information Center

    Palandra, Maria; Puigdollers, Carmen

    This Spanish reader for children in kindergarten and first grade is about a drop of water that comes to life in a trip through the water cycle of evaporation, condensation, and subsequent return to a drier part of the earth's surface environment. The story is suitable for reading aloud or independent reading. The text is entirely in Spanish.…

  18. Tear evaporation from the ocular surface.

    PubMed

    Tsubota, K; Yamada, M

    1992-09-01

    A simple method was developed to measure tear evaporation. A sensor was inserted into a chamber covering the eye. The humidity inside each chamber then was measured every 10 sec for 2 min with both eyes either closed or open but allowing normal blinking. The difference between these conditions represented evaporation from the ocular surface. Using this method, the tear evaporation rate at 40% ambient humidity (TEROS 40) was calculated. The average TEROS 40 in normal subjects (n = 43) was 15.6 +/- 3.8 x 10(-7) g/sec. It was 9.5 +/- 5.6 x 10(-7) g/sec in patients with dry eye symptoms (n = 72, P less than 0.001). The insertion of lacrimal collagen implants in one group of such patients (n = 10) increased the TEROS 40 from 10.2 +/- 5.5 x 10(-7) g/sec to 18.2 +/- 4.8 x 10(-7) g/sec (P less than 0.01). The instillation of eye drops increased the TEROS 40 significantly in patients with dry eye symptoms for at least 1 min (n = 10, P less than 0.01); a continued effect depended on the type of eye drop. Increased TEROS 40 still was observed 5 min after instillation of viscous eye drops (0.1% and 0.3% sodium hyaluronic acid); the TEROS 40 returned to original levels within 5 min after instillation of artificial tears of normal viscosity with or without 0.05% sodium hyaluronate. In all cases, TEROS 40 returned to original levels within 10 min. This was a quick reliable method for measuring tear evaporation from the ocular surface, and it can be applied to evaluate tear dynamics and subclassifications of dry eyes. PMID:1526744

  19. Simulation of a refrigerant evaporator

    NASA Astrophysics Data System (ADS)

    Vandermeer, Jakob Stefanus

    A computer model for the design and optimization of the compressor refrigeration cycle especially with respect to dynamic behavior was developed. A steady state version was also developed. The model describing the refrigerant is divided into the evaporation and superheating regions. A mechanism based on empirics corrects the model for the influence of transportation times in the evaporation region. The mass balance of the refrigerant in the superheat region is regarded as quasi-static, because of the small mass of the vapor. The energy balance accounts for a distributed model and is represented by the steady state solution of the partial differential equation which describes this area for the steady conditions. A correction for the dynamical effects was added to this solution, for all influencing parameters, according to the analytical dynamic solution for the case of the evaporation temperature as input parameter. The expansion device model was worked out for the usual type of device in combination with a dry evaporator, the thermostatic expansion valve. Validation tests are described.

  20. Evaporative Cooling Membrane Device

    NASA Technical Reports Server (NTRS)

    Lomax, Curtis (Inventor); Moskito, John (Inventor)

    1999-01-01

    An evaporative cooling membrane device is disclosed having a flat or pleated plate housing with an enclosed bottom and an exposed top that is covered with at least one sheet of hydrophobic porous material having a thin thickness so as to serve as a membrane. The hydrophobic porous material has pores with predetermined dimensions so as to resist any fluid in its liquid state from passing therethrough but to allow passage of the fluid in its vapor state, thereby, causing the evaporation of the fluid and the cooling of the remaining fluid. The fluid has a predetermined flow rate. The evaporative cooling membrane device has a channel which is sized in cooperation with the predetermined flow rate of the fluid so as to produce laminar flow therein. The evaporative cooling membrane device provides for the convenient control of the evaporation rates of the circulating fluid by adjusting the flow rates of the laminar flowing fluid.

  1. Effect of meibomian lipid layer on evaporation of tears

    NASA Astrophysics Data System (ADS)

    Miano, F.; Calcara, M.; Giuliano, F.; Millar, T. J.; Enea, V.

    2004-07-01

    The outer interface of a tear film was studied with the aid of a model system able to investigate the interfacial phenomena derived from the spreading of an insoluble lipid multilayer onto a tear-like aqueous fluid. The interactions of such a layer with proteins dissolved in the aqueous phase beneath were also investigated. Emphasis was given to evaporation phenomena because the increased rate of tear evaporation in humans is often related to a number of ocular dysfunctions. The model tear was studied as a pendant drop that permitted a functional evaluation of the effect of lipids and proteins upon the evaporation of water from the tear film.

  2. Control of solvent evaporation in hen egg white lysozyme crystallization

    NASA Technical Reports Server (NTRS)

    Wilson, L. J.; Suddath, F. L.

    1992-01-01

    An investigation of the role of solvent evaporation in tetragonal lysozyme crystallization was preformed with a device that employs N2(g) to control the evaporation of solvent from a micro-volume crystallization hanging drop. The number of crystals was found to vary with the rate at which the final supersaturation level was achieved. It was found that the more rapid the approach to supersaturation the larger the number of crystals. Accordingly, the crystals reached a smaller terminal size. Elongation of the (110) face parallel to the four-fold axis was observed with the slower evaporation rates.

  3. EFFECT OF LASER LIGHT ON MATTER. LASER PLASMAS: Effects of CO2 laser radiation on large orthophosphoric acid and water drops and on spherical ice crystals

    NASA Astrophysics Data System (ADS)

    Rudash, V. K.

    1994-02-01

    An experimental investigation is reported of the conditions present during evaporation of suspended orthophosphoric acid and water drops, and of spherical ice crystals with a radius of the order of 1 mm when the laser radiation power density was 20-104 W cm-2 at the wavelength of 10.6 μm. The lower limit of explosive evaporation was determined for H3PO4 drops and ice crystals. Only one evaporation mechanism of H3PO4 drops was observed (this mechanism was explosive), but there were two mechanisms in the case of water drops (convective with vapour ejection and explosive) and spherical ice crystals (melting followed by evaporation of a water drop and explosive evaporation). Repeated explosions of H2O drops were observed for a power density w = 104 W cm-2 when the beam diameter was 10 mm.

  4. Crack formation and prevention in colloidal drops.

    PubMed

    Kim, Jin Young; Cho, Kun; Ryu, Seul-A; Kim, So Youn; Weon, Byung Mook

    2015-01-01

    Crack formation is a frequent result of residual stress release from colloidal films made by the evaporation of colloidal droplets containing nanoparticles. Crack prevention is a significant task in industrial applications such as painting and inkjet printing with colloidal nanoparticles. Here, we illustrate how colloidal drops evaporate and how crack generation is dependent on the particle size and initial volume fraction, through direct visualization of the individual colloids with confocal laser microscopy. To prevent crack formation, we suggest use of a versatile method to control the colloid-polymer interactions by mixing a nonadsorbing polymer with the colloidal suspension, which is known to drive gelation of the particles with short-range attraction. Gelation-driven crack prevention is a feasible and simple method to obtain crack-free, uniform coatings through drying-mediated assembly of colloidal nanoparticles. PMID:26279317

  5. Crack formation and prevention in colloidal drops

    NASA Astrophysics Data System (ADS)

    Kim, Jin Young; Cho, Kun; Ryu, Seul-A.; Kim, So Youn; Weon, Byung Mook

    2015-08-01

    Crack formation is a frequent result of residual stress release from colloidal films made by the evaporation of colloidal droplets containing nanoparticles. Crack prevention is a significant task in industrial applications such as painting and inkjet printing with colloidal nanoparticles. Here, we illustrate how colloidal drops evaporate and how crack generation is dependent on the particle size and initial volume fraction, through direct visualization of the individual colloids with confocal laser microscopy. To prevent crack formation, we suggest use of a versatile method to control the colloid-polymer interactions by mixing a nonadsorbing polymer with the colloidal suspension, which is known to drive gelation of the particles with short-range attraction. Gelation-driven crack prevention is a feasible and simple method to obtain crack-free, uniform coatings through drying-mediated assembly of colloidal nanoparticles.

  6. Crack formation and prevention in colloidal drops

    PubMed Central

    Kim, Jin Young; Cho, Kun; Ryu, Seul-a; Kim, So Youn; Weon, Byung Mook

    2015-01-01

    Crack formation is a frequent result of residual stress release from colloidal films made by the evaporation of colloidal droplets containing nanoparticles. Crack prevention is a significant task in industrial applications such as painting and inkjet printing with colloidal nanoparticles. Here, we illustrate how colloidal drops evaporate and how crack generation is dependent on the particle size and initial volume fraction, through direct visualization of the individual colloids with confocal laser microscopy. To prevent crack formation, we suggest use of a versatile method to control the colloid-polymer interactions by mixing a nonadsorbing polymer with the colloidal suspension, which is known to drive gelation of the particles with short-range attraction. Gelation-driven crack prevention is a feasible and simple method to obtain crack-free, uniform coatings through drying-mediated assembly of colloidal nanoparticles. PMID:26279317

  7. Drop Tower Workshop

    NASA Technical Reports Server (NTRS)

    Urban, David

    2013-01-01

    Ground based microgravity facilities are an important proving ground for space experiments, ground-based research and space hardware risk mitigation. An overview of existing platforms will be discussed with an emphasis on drop tower capabilities. The potential for extension to partial gravity conditions will be discussed. Input will be solicited from attendees for their potential to use drop towers in the future and the need for enhanced capabilities (e.g. partial gravity)

  8. Flame propagation in heterogeneous mixtures of fuel drops and air

    NASA Technical Reports Server (NTRS)

    Myers, G. D.; Lefebvre, A. H.

    1984-01-01

    Photographic methods are used to measure flame speeds in flowing mixtures of fuel props and air at atmospheric pressure. The fuels employed include a conventional fuel oil plus various blends JP 7 with stocks containing single-ring and mullti-ring aromatics. The results for stoichiometric mixtures show that flame propagation cannot occur in mixtures containing mean drop sizes larger than 300 to 400 microns, depending on the fuel type. For smaller drop sizes, down to around 60 microns, flame speed is inversely proportional to drop size, indicating that evaporation rates are limiting to flame speed. Below around 60 microns, the curves of flame speed versus mean drop size flatten out, thereby demonstrating that for finely atomized sprays flame speeds are much less dependent on evaporation rates, and are governed primarily by mixing and/or chemical reaction rates. The fuels exhibiting the highest flame speeds are those containing multi-ring aromatics. This is attributed to the higher radiative heat flux emanating from their soot-bearing flames which enhances the rate of evaporation of the fuel drops approaching the flame front.

  9. Liquid metal drop ejection

    NASA Technical Reports Server (NTRS)

    Khuri-Yakub, B. T.

    1993-01-01

    The aim of this project was to demonstrate the possibility of ejecting liquid metals using drop on demand printing technology. The plan was to make transducers for operation in the 100 MHz frequency range and to use these transducers to demonstrate the ability to eject drops of liquid metals such as gallium. Two transducers were made by indium bonding piezoelectric lithium niobate to quartz buffer rods. The lithium niobate plates were thinned by mechanical polishing to a thickness of 37 microns for operation at 100 MHz. Hemispherical lenses were polished in the opposite ends of the buffer rods. The lenses, which focus the sound waves in the liquid metal, had an F-number equals 1. A mechanical housing was made to hold the transducers and to allow precise control over the liquid level above the lens. We started by demonstrating the ability to eject drops of water on demand. The drops of water had a diameter of 15 microns which corresponds to the wavelength of the sound wave in the water. A videotape of this ejection was made. We then used a mixture of Gallium and Indium (used to lower the melting temperature of the Gallium) to demonstrate the ejection of liquid metal drops. This proved to be difficult because of the oxide skin which forms on the surface of the liquid. In some instances, we were able to eject metal drops, however, this was not consistent and reproducible. An experiment was set up at NASA-Lewis to stabilize the process of drop on demand liquid metal ejection. The object was to place the transducer and liquid metal in a vacuum station so that no oxide would form on the surface. We were successful in demonstrating that liquid metals could be ejected on demand and that this technology could be used for making sheet metal in space.

  10. Performance evaluation of indirect evaporative cooler using clay pot

    NASA Astrophysics Data System (ADS)

    Ramkumar, R.; Ragupathy, A.

    2016-05-01

    The aim of the experimental study is to investigate the performance of indirect evaporator cooler in hot and humid regions. A novel approach is implemented in the cooler using clay pot with different position (single, double and three pots) and different orientation as aligned and staggered position for potential and feasibility study. The clay pot is the ceramic material where the water filled inside the pot and due to the property of porosity, the water comes outer surface of the pot and contact with the air passing over the pot surface and air get cooled. A test rig was designed and fabricated to collect experimental data. The clay pots were arranged in aligned and staggered position. In our study heat transfer was analysed with various air velocity of 1m/s to 5m/s. The air temperature, relative humidity, pressure drop and effectiveness were measured and the performance of the evaporative cooler was evaluated. The analysis of the data indicated that cooling effectiveness improve with decrease of air velocity at staggered position. It was shown that staggered position has the higher performance (57%) at 1 m/s air velocity comparison with aligned position values at three pots position.

  11. Quantifying nonisothermal subsurface soil water evaporation

    NASA Astrophysics Data System (ADS)

    Deol, Pukhraj; Heitman, Josh; Amoozegar, Aziz; Ren, Tusheng; Horton, Robert

    2012-11-01

    Accurate quantification of energy and mass transfer during soil water evaporation is critical for improving understanding of the hydrologic cycle and for many environmental, agricultural, and engineering applications. Drying of soil under radiation boundary conditions results in formation of a dry surface layer (DSL), which is accompanied by a shift in the position of the latent heat sink from the surface to the subsurface. Detailed investigation of evaporative dynamics within this active near-surface zone has mostly been limited to modeling, with few measurements available to test models. Soil column studies were conducted to quantify nonisothermal subsurface evaporation profiles using a sensible heat balance (SHB) approach. Eleven-needle heat pulse probes were used to measure soil temperature and thermal property distributions at the millimeter scale in the near-surface soil. Depth-integrated SHB evaporation rates were compared with mass balance evaporation estimates under controlled laboratory conditions. The results show that the SHB method effectively measured total subsurface evaporation rates with only 0.01-0.03 mm h-1difference from mass balance estimates. The SHB approach also quantified millimeter-scale nonisothermal subsurface evaporation profiles over a drying event, which has not been previously possible. Thickness of the DSL was also examined using measured soil thermal conductivity distributions near the drying surface. Estimates of the DSL thickness were consistent with observed evaporation profile distributions from SHB. Estimated thickness of the DSL was further used to compute diffusive vapor flux. The diffusive vapor flux also closely matched both mass balance evaporation rates and subsurface evaporation rates estimated from SHB.

  12. A posterirori study of models for large eddy simulations of drop-laden flows

    NASA Technical Reports Server (NTRS)

    Leboissetier, A.; Okong'o, N. A.; Bellan, J.

    2003-01-01

    Large Eddy Simulation (LES) is conducted of a three-dimensional temporal mixing layer whose stream is initially laden with liquid drops which may evaporate during the simulation. The gas-phase equations are written in Eulerian frame for two perfect gas species (carrier gas and vapor emanating from the drops), while the liquid-phase equations are written in a Lagrangian frame.

  13. Low-cost thin-film absorber/evaporator for an absorption chiller. Final report, May 1992-April 1993

    SciTech Connect

    Lowenstein, A.; Sibilia, M.

    1993-04-01

    The feasibility of making the absorber and evaporator of a small lithium-bromide absorption chiller from thin plastic films was studied. Tests were performed to measure (1) pressure limitations for a plastic thin-film heat exchanger, (2) flow pressure-drop characteristics, (3) air permeation rates across the plastic films, and (4) creep characteristics of the plastic films. Initial tests were performed on heat exchangers made of either low-density polyethylene (LDPE), high-density polyethylene (HDPE), or a LDPE/HDPE blend. While initial designs for the heat exchanger failed at internal pressures of only 5 to 6 psi, the final design could withstand pressures of 34 psi.

  14. CAPSULE REPORT: EVAPORATION PROCESS

    EPA Science Inventory

    Evaporation has been an established technology in the metal finishing industry for many years. In this process, wastewaters containing reusable materials, such as copper, nickel, or chromium compounds are heated, producing a water vapor that is continuously removed and condensed....

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

    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.

  16. Measure Guideline: Evaporative Condensers

    SciTech Connect

    German, A.; Dakin, B.; Hoeschele, M.

    2012-03-01

    The purpose of this measure guideline on evaporative condensers is to provide information on a cost-effective solution for energy and demand savings in homes with cooling loads. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices. This document has been prepared to provide a process for properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs.

  17. Mixed feed evaporator

    DOEpatents

    Vakil, Himanshu B.; Kosky, Philip G.

    1982-01-01

    In the preparation of the gaseous reactant feed to undergo a chemical reaction requiring the presence of steam, the efficiency of overall power utilization is improved by premixing the gaseous reactant feed with water and then heating to evaporate the water in the presence of the gaseous reactant feed, the heating fluid utilized being at a temperature below the boiling point of water at the pressure in the volume where the evaporation occurs.

  18. Evaporation study at Warm Springs Reservoir, Oregon

    USGS Publications Warehouse

    Harris, D.D.

    1968-01-01

    The mass transfer-water budget method of computing reservoir evaporation was tested on Warm Springs Reservoir, whose contents and surface area change greatly from early spring to late summer. The mass-transfer coefficient computed for the reservoir is two to three times greater than expected and results in a computed evaporation much greater than that from a land pan. Because of the remoteness of the area, the recommended study technique was modified, which could have reduced the accuracy of the results.

  19. The origin of star-shaped oscillations of Leidenfrost drops

    NASA Astrophysics Data System (ADS)

    Ma, Xiaolei; Burton, Justin C.

    We experimentally investigate the oscillations of Leidenfrost drops of water, liquid nitrogen, ethanol, methanol, acetone and isopropyl alcohol. The drops levitate on a cushion of evaporated vapor over a hot, curved surface which keeps the drops stationary. We observe star-shaped modes along the periphery of the drop, with mode numbers n = 2 to 13. The number of observed modes is sensitive to the properties of the liquid. The pressure oscillation frequency in the vapor layer under the drop is approximately twice that of the drop frequency, which is consistent with a parametric forcing mechanism. However, the Rayleigh and thermal Marangoni numbers are of order 10,000, indicating that convection should play a dominating role as well. Surprisingly, we find that the wavelength and frequency of the oscillations only depend on the thickness of the liquid, which is twice the capillary length, and do not depend on the mode number, substrate temperature, or the substrate curvature. This robust behavior suggests that the wavelength for the oscillations is set by thermal convection inside the drop, and is less dependent on the flow in the vapor layer under the drop

  20. Two stage indirect evaporative cooling system

    DOEpatents

    Bourne, Richard C.; Lee, Brian E.; Callaway, Duncan

    2005-08-23

    A two stage indirect evaporative cooler that moves air from a blower mounted above the unit, vertically downward into dry air passages in an indirect stage and turns the air flow horizontally before leaving the indirect stage. After leaving the dry passages, a major air portion travels into the direct stage and the remainder of the air is induced by a pressure drop in the direct stage to turn 180.degree. and returns horizontally through wet passages in the indirect stage and out of the unit as exhaust air.

  1. Investigation of drop motion through circular orifices

    NASA Astrophysics Data System (ADS)

    Bordoloi, Ankur; Longmire, Ellen; Kong, Xiangzhao; Saar, Martin

    2011-11-01

    The motion of drops though porous media occurs in numerous science and engineering fields including multiphase fluid flow in the subsurface during groundwater flow, geothermal energy recovery, and geologic carbon dioxide sequestration. Here, we simplify the porous medium to a thin plate with an orifice to study the interactions between the drop and the solid medium. Drops of water/glycerin with diameter, D, are released in a tank of silicone oil with matched refractive index and allowed to fall downward by gravity. After reaching terminal speed, the drops encounter a thin plate with orifice diameter, d, placed horizontally within the surrounding tank. Drop deformation, contact with the orifice, and breakage are investigated using high-speed imaging, and velocity fields are determined by particle image velocimetry (PIV). Effects of diameter ratio d/D, drop Reynolds number, and drop offset with respect to the orifice center are examined. The experimental results are compared to results from numerical simulations using an immiscible, two-color BGK lattice-Boltzmann method performed under similar test conditions. Supported by DOE (DOE EERE-PMC-10EE0002764).

  2. Does groundwater enhance evaporative cooling?

    NASA Astrophysics Data System (ADS)

    Rouholahnejad, E.

    2015-12-01

    Evaporation is a key process in land-climate interactions, not only because it directly regulates the hydrological cycle, but also because it contributes to the Earth's energy balance. Due to its feedbacks on large-scale water processes and its impact on the dynamics of the atmosphere, it has been considered as a driver of droughts and heatwaves1-3. While evaporation from ocean surfaces is likely to increase with rising temperatures, it is unclear whether evapotranspiration from land surfaces could similarly increase, due to possible limitations imposed by soil moisture and vegetation physiology4. Observations suggest that groundwater (hereafter GW) has an important role in hydrological budgets and soil moisture variability in many regions, supplying moisture for evapotranspiration during dry seasons5, 6. Although modeling studies suggest that GW is often close enough to the surface to interact with the atmosphere7, 8, the soil water storage is often underestimated by land surface models. This is most likely due to neglecting the lateral movement of water from topographically higher altitudes to valley bottoms and its convergence close to the land surface, as well as the upward movement of water in the capillary fringe.The focus of this study is to understand where and when GW may significantly enhance the availability of soil water for evapotranspiration. We also quantified the potential contribution of GW to evapotranspiration in the areas where GW is a major supply. We used the global network of eddy covariance observations9 (FLUXNET) along with global modeled GW depth10 and GLEAM ET model estimates11 to address the current gap in modelling ET due to neglecting GW supply. Having identified areas where GW is tightly coupled with the atmosphere through evaporation processes, the study provides the basis to examine the "air conditioning effect" of GW and test the idea if GW enhances evaporation to the extent that leads to a cooler temperatures and wetter climates.

  3. Modeling of drop breakup in the bag breakup regime

    NASA Astrophysics Data System (ADS)

    Wang, C.; Chang, S.; Wu, H.; Xu, J.

    2014-04-01

    Several analytic models for predicting the drop deformation and breakup have been developed over the last three decades, but modeling drop breakup in the bag-type regime is less reported. In this Letter, a breakup model has been proposed to predict the drop deformation length and breakup time in the bag-type breakup regime in a more accurate manner. In the present model, the drop deformation which is approximately as the displacement of the centre of mass (c. m.) along the axis located at the centre of the drop, and the movement of c. m. is obtained by solving the pressure balance equation. The effects of the drop deformation on the drop external aerodynamic force are considered in this model. Drop breakup occurs when the deformation length reaches the maximum value and the maximum deformation length is a function of Weber number. The performance and applicability of the proposed breakup model are tested against the published experimental data.

  4. The structure of evaporating and combusting sprays: Measurements and predictions

    NASA Astrophysics Data System (ADS)

    Shuen, J. S.; Solomon, A. S. P.; Faeth, G. M.

    1984-07-01

    An apparatus developed, to allow observations of monodisperse sprays, consists of a methane-fueled turbulent jet diffusion flame with monodisperse methanol drops injected at the burner exit. Mean and fluctuating-phase velocities, drop sizes, drop-mass fluxes and mean-gas temperatures were measured. Initial drop diameters of 100 and 180 microns are being considered in order to vary drop penetration in the flow and effects of turbulent dispersion. Baseline tests of the burner flame with no drops present were also conducted. Calibration tests, needed to establish methods for predicting drop transport, involve drops supported in the post-flame region of a flat-flame burner operated at various mixture ratios. Spray models which are being evaluated include: (1) locally homogeneous flow (LFH) analysis, (2) deterministic separated flow (DSF) analysis and (3) stochastic separated flow (SSF) analysis.

  5. The structure of evaporating and combusting sprays: Measurements and predictions

    NASA Technical Reports Server (NTRS)

    Shuen, J. S.; Solomon, A. S. P.; Faeth, G. M.

    1984-01-01

    An apparatus developed, to allow observations of monodisperse sprays, consists of a methane-fueled turbulent jet diffusion flame with monodisperse methanol drops injected at the burner exit. Mean and fluctuating-phase velocities, drop sizes, drop-mass fluxes and mean-gas temperatures were measured. Initial drop diameters of 100 and 180 microns are being considered in order to vary drop penetration in the flow and effects of turbulent dispersion. Baseline tests of the burner flame with no drops present were also conducted. Calibration tests, needed to establish methods for predicting drop transport, involve drops supported in the post-flame region of a flat-flame burner operated at various mixture ratios. Spray models which are being evaluated include: (1) locally homogeneous flow (LFH) analysis, (2) deterministic separated flow (DSF) analysis and (3) stochastic separated flow (SSF) analysis.

  6. The simultaneous mass and energy evaporation (SM2E) model.

    PubMed

    Choudhary, Rehan; Klauda, Jeffery B

    2016-01-01

    In this article, the Simultaneous Mass and Energy Evaporation (SM2E) model is presented. The SM2E model is based on theoretical models for mass and energy transfer. The theoretical models systematically under or over predicted at various flow conditions: laminar, transition, and turbulent. These models were harmonized with experimental measurements to eliminate systematic under or over predictions; a total of 113 measured evaporation rates were used. The SM2E model can be used to estimate evaporation rates for pure liquids as well as liquid mixtures at laminar, transition, and turbulent flow conditions. However, due to limited availability of evaporation data, the model has so far only been tested against data for pure liquids and binary mixtures. The model can take evaporative cooling into account and when the temperature of the evaporating liquid or liquid mixture is known (e.g., isothermal evaporation), the SM2E model reduces to a mass transfer-only model. PMID:26595699

  7. Digitizing of drop table output

    SciTech Connect

    Muncy, K.

    1984-01-01

    The method for monitoring and analyzing the drop pulses from the MTS1212 drop table system has been upgraded from a labor intensive manual system to an automatic digital system. The pulse from each drop is recorded, analyzed and printed out. The data printed out includes all product information, the drop parameters calculated and a plot of the drop pulse. Some of the advantages of this system, besides the replacement of old and obsolete equipment, include the dropping of the repeatability check requirement, ease of operation, complete automatic documentation of each drop, no need to take Polaroid pictures of a drop nor is it necessary to have a drop film read by the film analysis group. Data comparisons between the old method and the new digital method have been very favorable.

  8. Evaporator Development for an Evaporative Heat Pipe System

    NASA Technical Reports Server (NTRS)

    Peters, Leigh C.

    2004-01-01

    As fossil fuel resources continue to deplete, research for alternate power sources continues to develop. One of these alternate technologies is fuel cells. They are a practical fuel source able to provide significant amounts of power for applications from laptops to automobiles and their only byproduct is water. However, although this technology is over a century old and NASA has been working with it since the early 1960 s there is still room for improvement. The research I am involved in at NASA's Glenn Research Center is focusing on what is called a regenerative fuel cell system. The unique characteristic of this type of system is that it used an outside power source to create electrolysis of the water it produces and it then reuses the hydrogen and oxygen to continue producing power. The advantage of this type of system is that, for example, on space missions it can use solar power to recharge its gas supplies between periods when the object being orbited blocks out the sun. This particular system however is far from completion. This is because of the many components that are required to make up a fuel cell that need to be tested individually. The specific part of the system that is being worked on this summer of 2004 is the cooling system. The fuel cell stack, that is the part that actually creates the power, also produces a lot of heat. When not properly cooled, it has been known to cause fires which, needless to say are not conducive to the type of power that is trying to be created. In order to cool the fuel cell stack in this system we are developing a heat pipe cooling system. One of the main components of a heat pipe cooling system is what is known as the evaporator, and that is what happens to be the part of the system we are developing this summer. In most heat pipe systems the evaporator is a tube in which the working fluid is cooled and then re-circulated through the system to absorb more heat energy from the fuel cell stack. For this system, instead

  9. Prediction of Heat Transfer Characteristics of Binary Refrigerant Mixtures in a Falling Film Type Plate-fin Evaporator

    NASA Astrophysics Data System (ADS)

    Yara, Tomoyasu; Koyama, Shigeru

    This paper deals with the characteristics of heat transfer and pressure drop of R 22, R 134a pure refrigerant and R 134a/R123 refrigerant mixtures in a falling film type plate-fin evaporator. The refrigerants have been tested in the ranges of heat flux from 3 to 20 kW/m2 and mass velocity from 50 to 100 kg/m2s. It is clarified that heat transfer characteristics of evaporation in the present experimental range are not affected by shear stress. Taking the fin efficiency into consideration, a correlation equation of heat transfer coefficient is proposed. The characteristic of pressure drop is also proposed by modifying friction factor of Soliman's equation. Furthermore, a prediction model for evaporation of mixtures in a plate fin heat exchanger is developed based on the assumption that the phase equilibrium in a cross-section of the refrigerant path is established. The prediction results are in good agreement with the experimental data.

  10. Drop tube technical tasks

    NASA Technical Reports Server (NTRS)

    Workman, G. L.

    1986-01-01

    Criteria, using fundamental thermochemical dynamics, were developed to assist a scientist using the Drop Tube Facility in designing a good experiment. The types of parameters involved in designing the experiments include the type of furnace, the type of atmosphere, and in general which materials are better behaved than others as determined by past experience in the facility. One of the major advantages of the facility lies in its ability to provide large undercoolings in the cooling curve during the drops. A beginning was to consider the effect of oxygen and other gases upon the amount of undercooling observed. The starting point of the thermochemistry was given by Ellingham and later transformed into what is known as the Richardson Chart. The effect of surface oxidations upon the nucleation phenomena can be observed in each specimen.

  11. Hot air drum evaporator

    DOEpatents

    Black, Roger L.

    1981-01-01

    An evaporation system for aqueous radioactive waste uses standard 30 and 55 gallon drums. Waste solutions form cascading water sprays as they pass over a number of trays arranged in a vertical stack within a drum. Hot dry air is circulated radially of the drum through the water sprays thereby removing water vapor. The system is encased in concrete to prevent exposure to radioactivity. The use of standard 30 and 55 gallon drums permits an inexpensive compact modular design that is readily disposable, thus eliminating maintenance and radiation build-up problems encountered with conventional evaporation systems.

  12. Optimization of evaporative cooling

    NASA Astrophysics Data System (ADS)

    Sackett, C. A.; Bradley, C. C.; Hulet, R. G.

    1997-05-01

    Recent experiments have used forced evaporative cooling to produce Bose-Einstein condensation in dilute gases. The evaporative cooling process can be optimized to provide the maximum phase-space density with a specified number of atoms remaining. We show that this global optimization is approximately achieved by locally optimizing the cooling efficiency at each instant. We discuss how this method can be implemented, and present the results for our 7Li trap. The predicted behavior of the gas is found to agree well with experiment.

  13. Exploding Water Drops

    NASA Astrophysics Data System (ADS)

    Reich, Gary

    2016-01-01

    Water has the unusual property that it expands on freezing, so that ice has a specific gravity of 0.92 compared to 1.0 for liquid water. The most familiar demonstration of this property is ice cubes floating in a glass of water. A more dramatic demonstration is the ice bomb shown in Fig. 1. Here a cast iron flask is filled with water and tightly stoppered. The flask is then cooled, either by leaving it outdoors in winter or by immersing it in a cryogenic fluid, until the water freezes. As the water freezes and expands, the pressure inside the flask increases dramatically, eventually becoming sufficient to fracture the metal walls of the enclosure. A related, but much less familiar, phenomenon is the explosive fracturing of small water drops upon freezing. That water drops can fracture in this way has been known for many years, and the phenomenon has been described in detail in the atmospheric sciences literature, where it is seen as relevant to the freezing of raindrops as they fall through cold air. Carefully controlled experiments have been done documenting how the character and frequency of fracture is affected by such variables as drop size, rate of cooling, chemistry of dissolved gases, etc. Here I describe instead a simple demonstration of fracture suitable for video analysis and appropriate for study at the introductory physics level. Readers may also be interested in other characteristics of freezing and fragmenting water drops, for example, charge separation upon fracture and the appearance of spikes and bulges on the surface.

  14. Time-resolved interference unveils nanoscale surface dynamics in evaporating sessile droplet

    NASA Astrophysics Data System (ADS)

    Verma, Gopal; Singh, Kamal P.

    2014-06-01

    We report a simple optical technique to measure time-resolved nanoscale surface profile of an evaporating sessile fluid droplet. By analyzing the high contrast Newton-ring like dynamical fringes formed by interfering Fresnel reflections, we demonstrated λ/100 ≈ 5 nm sensitivity in surface height (at 0.01-160 nm/s rate) of an evaporating water drop. The remarkably high sensitivity allowed us to precisely measure its transient surface dynamics during contact-line slips, weak perturbations on the evaporation due to external magnetic field and partial confinement of the drop. Further, we measured evaporation dynamics of a sessile water drop on soft deformable surface to demonstrate wide applicability of this technique.

  15. Drying of a coffee drop: differences between dry and wet tables?

    NASA Astrophysics Data System (ADS)

    Boulogne, François; Ingremeau, François; Stone, Howard

    2015-11-01

    We have all experienced that a coffee drop drying on a table leaves a ring stain. The radial flow in the drop coupled with a larger drying flux at its edge are the reasons for the particle accumulation in the liquid wedge. However, if the substrate is wet, the liquid surrounding the drop modifies the vapor distribution, and thus the drop evaporation dynamics. Our experimental observations show that the drying kinetics and the particle motion are affected by the ambient conditions. We rationalize our experimental findings with a model that describes the spatially varying evaporation as well as the temporal evolution of the particles forming the ring. We believe that these results are of practical interest for printing applications involving multiple drop systems or drying surfaces. F.B. acknowledges that the research leading to these results received funding from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme (FP7/2007-2013) under REA grant agreement 623541.

  16. Evaporation of petroleum products from contaminated soils

    SciTech Connect

    Kang, S.H.; Oulman, C.S.

    1996-05-01

    Bioremediation can remove petroleum products from soil that has been contaminated by leaking underground storage tanks, but abiotic processes such as evaporation can contribute significantly to the overall removal process. The mathematical model described in this paper was developed to predict the evaporation rate of volatile liquids from petroleum-contaminated sand. The model is based on simple concepts relating to molecular diffusion embodied in the theory underlying the estimation of binary diffusivities using measurements made with an Arnold diffusion cell. The model in its simplified form indicates that the rate of evaporation for a particular volatile liquid is proportional to the square root of the product of diffusivity and partial pressure divided by the molecular weight of the liquid. This in part explains why evaporative losses from sand are so much higher for gasoline than for diesel fuel. The model also shows that the time for evaporation is directly proportional to the square of the depth dried out and inversely proportional to the vapor pressure of the volatile liquid. The model was tested using gravimetric measurements of the evaporation of n-heptane, unleaded gasoline, and diesel fuel from sand under laboratory conditions.

  17. Waste Feed Evaporation Physical Properties Modeling

    SciTech Connect

    Daniel, W.E.

    2003-08-25

    This document describes the waste feed evaporator modeling work done in the Waste Feed Evaporation and Physical Properties Modeling test specification and in support of the Hanford River Protection Project (RPP) Waste Treatment Plant (WTP) project. A private database (ZEOLITE) was developed and used in this work in order to include the behavior of aluminosilicates such a NAS-gel in the OLI/ESP simulations, in addition to the development of the mathematical models. Mathematical models were developed that describe certain physical properties in the Hanford RPP-WTP waste feed evaporator process (FEP). In particular, models were developed for the feed stream to the first ultra-filtration step characterizing its heat capacity, thermal conductivity, and viscosity, as well as the density of the evaporator contents. The scope of the task was expanded to include the volume reduction factor across the waste feed evaporator (total evaporator feed volume/evaporator bottoms volume). All the physical properties were modeled as functions of the waste feed composition, temperature, and the high level waste recycle volumetric flow rate relative to that of the waste feed. The goal for the mathematical models was to predict the physical property to predicted simulation value. The simulation model approximating the FEP process used to develop the correlations was relatively complex, and not possible to duplicate within the scope of the bench scale evaporation experiments. Therefore, simulants were made of 13 design points (a subset of the points used in the model fits) using the compositions of the ultra-filtration feed streams as predicted by the simulation model. The chemistry and physical properties of the supernate (the modeled stream) as predicted by the simulation were compared with the analytical results of experimental simulant work as a method of validating the simulation software.

  18. Coalescing drops in microfluidic parking networks: A multifunctional platform for drop-based microfluidics

    PubMed Central

    Bithi, Swastika S.; Wang, William S.; Sun, Meng; Blawzdziewicz, Jerzy; Vanapalli, Siva A.

    2014-01-01

    Multiwell plate and pipette systems have revolutionized modern biological analysis; however, they have disadvantages because testing in the submicroliter range is challenging, and increasing the number of samples is expensive. We propose a new microfluidic methodology that delivers the functionality of multiwell plates and pipettes at the nanoliter scale by utilizing drop coalescence and confinement-guided breakup in microfluidic parking networks (MPNs). Highly monodisperse arrays of drops obtained using a hydrodynamic self-rectification process are parked at prescribed locations in the device, and our method allows subsequent drop manipulations such as fine-gradation dilutions, reactant addition, and fluid replacement while retaining microparticles contained in the sample. Our devices operate in a quasistatic regime where drop shapes are determined primarily by the channel geometry. Thus, the behavior of parked drops is insensitive to flow conditions. This insensitivity enables highly parallelized manipulation of drop arrays of different composition, without a need for fine-tuning the flow conditions and other system parameters. We also find that drop coalescence can be switched off above a critical capillary number, enabling individual addressability of drops in complex MPNs. The platform demonstrated here is a promising candidate for conducting multistep biological assays in a highly multiplexed manner, using thousands of submicroliter samples. PMID:25379078

  19. Coalescing drops in microfluidic parking networks: A multifunctional platform for drop-based microfluidics.

    PubMed

    Bithi, Swastika S; Wang, William S; Sun, Meng; Blawzdziewicz, Jerzy; Vanapalli, Siva A

    2014-05-01

    Multiwell plate and pipette systems have revolutionized modern biological analysis; however, they have disadvantages because testing in the submicroliter range is challenging, and increasing the number of samples is expensive. We propose a new microfluidic methodology that delivers the functionality of multiwell plates and pipettes at the nanoliter scale by utilizing drop coalescence and confinement-guided breakup in microfluidic parking networks (MPNs). Highly monodisperse arrays of drops obtained using a hydrodynamic self-rectification process are parked at prescribed locations in the device, and our method allows subsequent drop manipulations such as fine-gradation dilutions, reactant addition, and fluid replacement while retaining microparticles contained in the sample. Our devices operate in a quasistatic regime where drop shapes are determined primarily by the channel geometry. Thus, the behavior of parked drops is insensitive to flow conditions. This insensitivity enables highly parallelized manipulation of drop arrays of different composition, without a need for fine-tuning the flow conditions and other system parameters. We also find that drop coalescence can be switched off above a critical capillary number, enabling individual addressability of drops in complex MPNs. The platform demonstrated here is a promising candidate for conducting multistep biological assays in a highly multiplexed manner, using thousands of submicroliter samples. PMID:25379078

  20. Anomalous water drop bouncing on a nanotextured surface by the Leidenfrost levitation

    NASA Astrophysics Data System (ADS)

    Lee, Doo Jin; Song, Young Seok

    2016-05-01

    We report an anomalous liquid drop bouncing phenomenon that is generated by the Leidenfrost levitation due to a vapor layer reducing energy dissipation during the collision. The Leidenfrost levitation of water drops on both a hydrophobic surface and nanotextured Cassie surface is investigated. When the water drop is positioned onto the hydrophobic surface, a superhydrophobic feature is observed by the levitation effect due to the vapor film, which results in a slow evaporation of the drop due to the low thermal conductivity of the vapor layer that inhibits heat transfer between the heated surface and the water drop. In contrast, for the nanotextured surface, the water drop can bounce off after impact on the surface when it overcomes gravitational and adhesion forces. The spontaneous water drop bouncing on the nanotextured surface is powered by the combination effect of the Leidenfrost levitation and the non-wetting Cassie state.

  1. Drop foot corrective device

    NASA Technical Reports Server (NTRS)

    Deis, B. C. (Inventor)

    1986-01-01

    A light weight, economical device to alleviate a plurality of difficulties encountered in walking by a victim suffering from a drop foot condition is discussed. A legband girdles the leg below the knee and above the calf providing an anchor point for the upper end of a ligament having its lower end attached to a toe of a shoe or a toe on the foot. The ligament is of such length that the foot is supported thereby and retained in a normal position during walking.

  2. How to Use Ear Drops

    MedlinePlus

    How to Use Ear Drops(Having someone else give you the ear drops may make this procedure easier.) Wash your hands thoroughly with soap and ... facecloth and then dry your ear. Warm the drops to near body temperature by holding the container ...

  3. Liquid drops impacting superamphiphobic coatings.

    PubMed

    Deng, Xu; Schellenberger, Frank; Papadopoulos, Periklis; Vollmer, Doris; Butt, Hans-Jürgen

    2013-06-25

    The dynamics of liquid drops impacting superamphiphobic coatings is studied by high-speed video microscopy. Superamphiphobic coatings repel water and oils. The coating consists of a fractal-like hydrophobized silica network. Mixtures of ethanol-water and glycerin-water are chosen to investigate the influence of interfacial tension and viscosity on spreading and retraction dynamics. Drop spreading is dominated by inertia. At low impact velocity, the drops completely rebound. However, the contact time increases with impact velocity, whereas the restitution coefficient decreases. We suggest that the drop temporarily impales the superamphiphobic coating, although the drop completely rebounds. From an estimate of the pressure, it can be concluded that impalement is dominated by depinning rather than sagging. With increasing velocity, the drops partially pin, and an increasing amount of liquid remains on the coating. A time-resolved study of the retraction dynamics reveals two well-separated phases: a fast inertia-dominated phase followed by a slow decrease of the contact diameter of the drop. The crossover occurs when the diameter of the retracting drop matches the diameter of the drop before impact. We suggest that the depth of impalement increases with impact velocity, where impalement is confined to the initial impact zone of the drop. If the drop partially pins on the coating, the depth of impalement exceeds a depth, preventing the whole drop from being removed during the retraction phase. PMID:23697383

  4. Probing loop quantum gravity with evaporating black holes.

    PubMed

    Barrau, A; Cailleteau, T; Cao, X; Diaz-Polo, J; Grain, J

    2011-12-16

    This Letter aims at showing that the observation of evaporating black holes should allow the usual Hawking behavior to be distinguished from loop quantum gravity (LQG) expectations. We present a full Monte Carlo simulation of the evaporation in LQG and statistical tests that discriminate between competing models. We conclude that contrarily to what was commonly thought, the discreteness of the area in LQG leads to characteristic features that qualify evaporating black holes as objects that could reveal quantum gravity footprints. PMID:22243065

  5. Dense spray evaporation as a mixing process

    NASA Astrophysics Data System (ADS)

    de Rivas, A.; Villermaux, E.

    2016-05-01

    We explore the processes by which a dense set of small liquid droplets (a spray) evaporates in a dry, stirred gas phase. A dense spray of micron-sized liquid (water or ethanol) droplets is formed in air by a pneumatic atomizer in a closed chamber. The spray is conveyed in ambient air as a plume whose extension depends on the relative humidity of the diluting medium. Standard shear instabilities develop at the plume edge, forming the stretched lamellar structures familiar with passive scalars. Unlike passive scalars however, these lamellae vanish in a finite time, because individual droplets evaporate at their border in contact with the dry environment. Experiments demonstrate that the lifetime of an individual droplet embedded in a lamellae is much larger than expected from the usual d2 law describing the fate of a single drop evaporating in a quiescent environment. By analogy with the way mixing times are understood from the convection-diffusion equation for passive scalars, we show that the lifetime of a spray lamellae stretched at a constant rate γ is tv=1/γ ln(1/+ϕ ϕ ) , where ϕ is a parameter that incorporates the thermodynamic and diffusional properties of the vapor in the diluting phase. The case of time-dependent stretching rates is examined too. A dense spray behaves almost as a (nonconserved) passive scalar.

  6. An evaporation model of colloidal suspension droplets

    NASA Astrophysics Data System (ADS)

    Sartori, Silvana; Li\\ Nán, Amable; Lasheras, Juan C.

    2009-11-01

    Colloidal suspensions of polymers in water or other solvents are widely used in the pharmaceutical industry to coat tablets with different agents. These allow controlling the rate at which the drug is delivered, taste or physical appearance. The coating is performed by simultaneously spraying and drying the tablets with the colloidal suspension at moderately high temperatures. The spreading of the coating on the pills surface depends on the droplet Webber and Reynolds numbers, angle of impact, but more importantly on the rheological properties of the drop. We present a model for the evaporation of a colloidal suspension droplet in a hot air environment with temperatures substantially lower than the boiling temperature of the carrier fluid. As the liquid vaporizes from the surface, a compacting front advances into the droplet faster than the liquid surface regresses, forming a shell of a porous medium where the particles reach their maximum packing density. While the surface regresses, the evaporation rate is determined by both the rate at which heat is transported to the droplet surface and the rate at which liquid vapor is diffused away from it. This regime continues until the compacting front reaches the center of the droplet, at which point the evaporation rate is drastically reduced.

  7. Ionization degree for strong evaporation of metals

    SciTech Connect

    Gusarov, Andrey V.; Aoki, Kazuo

    2005-08-15

    Kinetic equations for ions and neutrals are numerically solved in the plasma sheath formed at a condensed phase when strong evaporation is taking place. The Boltzmann distribution is assumed for electrons. A weakly ionized vapor with the Debye length much shorter than the mean free path is considered. This is typical for laser evaporation of metals. Under these conditions, the sheath consists of a Knudsen layer and a thin charge separation layer between the Knudsen layer and the condensed phase. The self-consistent electrostatic field in the Knudsen layer is obtained from the quasineutrality condition. The potential barrier in the charge separation layer is determined by the charge balance. Kinetic boundary conditions for neutrals and charges are estimated by the detailed balance principle from the parameters of the saturated vapor. The transport of charges in the sheath is controlled by ions and depends on ion-neutral collisions and the self-consistent electrostatic field. Ionization degree in the vapor formed by strong evaporation increases with the Mach number and can attain values about 30% higher than the ionization degree in the saturated vapor. Two factors contribute to this increase. The first is the drop of the potential barrier in the charge separation layer and the second is the strengthening of the field in the Knudsen layer. The ionization equilibrium may be disturbed by a considerable excess of charges.

  8. The Impact of the Correlation between the No Child Left Behind Act's High Stakes Testing and the High Drop-Out Rates of Minority Students

    ERIC Educational Resources Information Center

    Walden, Lavada M.; Kritsonis, William Allan

    2008-01-01

    The author looks at critical dialogue surrounding the causes for the alarming high numbers of high school dropouts in states that use high stakes standardized testing mandated by the No Child Left Behind Act, and investigates the perceived correlations between high stakes testing and high numbers of high school dropouts of minority students.

  9. MOVES2014: Evaporative Emissions Report

    EPA Science Inventory

    Vehicle evaporative emissions are now modeled in EPA’s MOVES according to physical processes, permeation, tank vapor venting, liquid leaks, and refueling emissions. With this update, the following improvements are being incorporated into MOVES evaporative emissions methodology, a...

  10. A numerical simulation of heat transfer in evaporative cooling towers

    NASA Astrophysics Data System (ADS)

    Benton, D. J.

    1983-09-01

    A phenomenological analysis was developed for the processes which occur within an evaporative cooling tower. The analysis includes the basic principles of mass, momentum, and energy conservation and empirical elationships for component characteristics such as transfer and pressure drop coefficients. A computer model which simulates the processes occurring in evaporative cooling towers was developed. The results of this computer model are compared to field data to verify the analysis and the computer modeling. The computer model may be used to analyze the performance of existing towers or to predict the performance of alternative tower designs.

  11. New Method Developed to Measure Contact Angles of a Sessile Drop

    NASA Technical Reports Server (NTRS)

    Chao, David F.; Zhang, Nengli

    2002-01-01

    The spreading of an evaporating liquid on a solid surface occurs in many practical processes and is of importance in a number of practical situations such as painting, textile dyeing, coating, gluing, and thermal engineering. Typical processes involving heat transfer where the contact angle plays an important role are film cooling, boiling, and the heat transfer through heat pipes. The biological phenomenon of cell spreading also is analogous to a drop spreading (ref. 1). In the study of spreading, the dynamic contact angle describes the interfacial properties on solid substrates and, therefore, has been studied by physicists and fluid mechanics investigators. The dynamic contact angle of a spreading nonvolatile liquid drop provides a simple tool in the study of the free-boundary problem, but the study of the spreading of a volatile liquid drop is of more practical interest because the evaporation of common liquids is inevitable in practical processes. The most common method to measure the contact angle, the contact radius, and the height of a sessile drop on a solid surface is to view the drop from its edge through an optical microscope. However, this method gives only local information in the view direction. Zhang and Yang (ref. 2) developed a laser shadowgraphy method to investigate the evaporation of sessile drop on a glass plate. As described here, Zhang and Chao (refs. 3 and 4) improved the method and suggested a new optical arrangement to measure the dynamic contact angle and the instant evaporation rate of a sessile drop with much higher accuracy (less than 1 percent). With this method, any fluid motion in the evaporating drop can be visualized through shadowgraphy without using a tracer, which often affects the field under investigation.

  12. Gravity Effects in Condensing and Evaporating Films

    NASA Technical Reports Server (NTRS)

    Hermanson, J. C.; Som, S. M.; Allen, J. S.; Pedersen, P. C.

    2004-01-01

    A general overview of gravity effects in condensing and evaporating films is presented. The topics include: 1) Research Overview; 2) NASA Recognizes Critical Need for Condensation & Evaporation Research to Enable Human Exploration of Space; 3) Condensation and Evaporation Research in Reduced Gravity is Enabling for AHST Technology Needs; 4) Differing Role of Surface Tension on Condensing/Evaporating Film Stability; 5) Fluid Mechanisms in Condensing and Evaporating Films in Reduced Gravity; 6) Research Plan; 7) Experimental Configurations for Condensing Films; 8) Laboratory Condensation Test Cell; 9) Aircraft Experiment; 10) Condensation Study Current Test Conditions; 11) Diagnostics; 12) Shadowgraph Images of Condensing n- pentane Film in Unstable (-1g) Configuration; 13) Condensing n-Pentane Film in Normal Gravity (-1g) at Constant Pressure; 14) Condensing n-Pentane Film in Normal Gravity (-1g) with Cyclic Pressure; 15) Non-condensing Pumped Film in Normal Gravity (-1g); 16) Heat Transfer Coefficient in Developing, Unstable Condensing Film in Normal Gravity; 17) Heat Transfer for Unsteady Condensing Film (-1g); 18) Ultrasound Measurement of Film Thickness N-pentane Film, Stable (+1g) Configuration; and 19) Ultrasound Measurement of Film Thickness N-pentane Film, Unstable (-1g) Configuration.

  13. Selected flows with free surfaces: Streams and drops

    NASA Astrophysics Data System (ADS)

    Kowalewski, Tomasz A.

    1995-03-01

    The basic purpose of the research described in this article was to develop a non contact method for diagnosing the physical parameters of the free surface of a liquid using drop oscillation analysis. In particular, the purpose is to measure the temperature of an evaporating surface. The realization of this goal has led to the development of new experimental techniques which make it possible to record fast processes using video and digital imaging equipment. Experimental studies of the process of the formation of drops as a result of the controlled breakup of a stream revealed the existence of an additional phase in the process based on the formation of microstreams and microsatellites with micrometer-like dimensions. A comparison of measurement results with Eggers' asymptotic model (23) confirmed the model's basic assumption of the local nature of the final phase in the disintegration of the stream, which at the same time points to the existence of a number of discrepancies which provide evidence of the limitations of this approximation. The next part of the article presents the results of observations of the instability of streams of liquid caused by its evaporation. In an attempt to analyze the mechanisms which initiate the turbulence of the evaporating surface, the author focused on surface tension gradients as an essential factor in the destabilization of small-diameter streams. The author also described the occurrence of a number of new phenomena in the destabilization of a stream, including the separation of surface fragments, their stabilization by the flow of vapor, and a quasistable change in the trajectory of the stream. The author also developed an experimental method which makes it possible to detect and produce a precise description of the deformation of drops. Measurements of the oscillations of small drops in the air led to the development of a complete non-linear model of the oscillations of a viscous drop and made it possible to verify simplified

  14. Evaporation heat transfer and friction characteristics of R-134a flowing downward in a vertical corrugated tube

    SciTech Connect

    Aroonrat, Kanit; Wongwises, Somchai

    2011-01-15

    Differently from most previous studies, the heat transfer and friction characteristics of the pure refrigerant HFC-134a during evaporation inside a vertical corrugated tube are experimentally investigated. The double tube test sections are 0.5 m long with refrigerant flowing in the inner tube and heating water flowing in the annulus. The inner tubes are one smooth tube and two corrugated tubes, which are constructed from smooth copper tube of 8.7 mm inner diameter. The test runs are performed at evaporating temperatures of 10, 15, and 20 C, heat fluxes of 20, 25, and 30 kW/m{sup 2}, and mass fluxes of 200, 300, and 400 kg/m{sup 2} s. The quality of the refrigerant in the test section is calculated using the temperature and pressure obtained from the experiment. The pressure drop across the test section is measured directly by a differential pressure transducer. The effects of heat flux, mass flux, and evaporation temperature on the heat transfer coefficient and two-phase friction factor are also discussed. It is found that the percentage increases of the heat transfer coefficient and the two-phase friction factor of the corrugated tubes compared with those of the smooth tube are approximately 0-10% and 70-140%, respectively. (author)

  15. Evaporated VOx Thin Films

    NASA Astrophysics Data System (ADS)

    Stapinski, Tomasz; Leja, E.

    1989-03-01

    VOx thin films on glass were obtained by thermal evaporation of V205, powder. The structural investigations were carried out with the use of X-ray diffractometer. The electrical properties of the film were examined by means of temperature measurements of resistivity for the samples heat-treated in various conditions. Optical transmission and reflection spectra of VOX films of various composition showed the influence of the heat treatment.

  16. Falling film evaporator

    DOEpatents

    Bruns, Lester E.

    1976-01-01

    A falling film evaporator including a vertically oriented pipe heated exteriorly by a steam jacket and interiorly by a finned steam tube, all heating surfaces of the pipe and steam tube being formed of a material wet by water such as stainless steel, and packing within the pipe consisting of Raschig rings formed of a material that is not wet by water such as polyvinylidene fluoride.

  17. Vertical counterflow evaporative cooler

    DOEpatents

    Bourne, Richard C.; Lee, Brian Eric; Callaway, Duncan

    2005-01-25

    An evaporative heat exchanger having parallel plates that define alternating dry and wet passages. A water reservoir is located below the plates and is connected to a water distribution system. Water from the water distribution system flows through the wet passages and wets the surfaces of the plates that form the wet passages. Air flows through the dry passages, mixes with air below the plates, and flows into the wet passages before exiting through the top of the wet passages.

  18. 242-16H 2H EVAPORATOR POT SAMPLING FINAL REPORT

    SciTech Connect

    Krementz, D; William Cheng, W

    2008-06-11

    Due to the materials that are processed through 2H Evaporator, scale is constantly being deposited on the surfaces of the evaporator pot. In order to meet the requirements of the Nuclear Criticality Safety Analysis/Evaluation (NCSA/NCSE) for 2H Evaporator, inspections of the pot are performed to determine the extent of scaling. Once the volume of scale reaches a certain threshold, the pot must be chemically cleaned to remove the scale. Prior to cleaning the pot, samples of the scale are obtained to determine the concentration of uranium and plutonium and also to provide information to assist with pot cleaning. Savannah River National Laboratory (SRNL) was requested by Liquid Waste Organization (LWO) Engineering to obtain these samples from two locations within the evaporator. Past experience has proven the difficulty of successfully obtaining solids samples from the 2H Evaporator pot. To mitigate this risk, a total of four samplers were designed and fabricated to ensure that two samples could be obtained. Samples had previously been obtained from the cone surface directly below the vertical access riser using a custom scraping tool. This tool was fabricated and deployed successfully. A second scraper was designed to obtain sample from the nearby vertical thermowell and a third scraper was designed to obtain sample from the vertical pot wall. The newly developed scrapers both employed a pneumatically actuated elbow. The scrapers were designed to be easily attached/removed from the elbow assembly. These tools were fabricated and deployed successfully. A fourth tool was designed to obtain sample from the opposite side of the pot under the tube bundle. This tool was fabricated and tested, but the additional modifications required to make the tool field-ready could not be complete in time to meet the aggressive deployment schedule. Two samples were obtained near the pot entry location, one from the pot wall and the other from the evaporator feed pipe. Since a third

  19. Controlling charge on levitating drops.

    PubMed

    Hilger, Ryan T; Westphall, Michael S; Smith, Lloyd M

    2007-08-01

    Levitation technologies are used in containerless processing of materials, as microscale manipulators and reactors, and in the study of single drops and particles. Presented here is a method for controlling the amount and polarity of charge on a levitating drop. The method uses single-axis acoustic levitation to trap and levitate a single, initially neutral drop with a diameter between 400 microm and 2 mm. This drop is then charged in a controllable manner using discrete packets of charge in the form of charged drops produced by a piezoelectric drop-on-demand dispenser equipped with a charging electrode. The magnitude of the charge on the dispensed drops can be adjusted by varying the voltage applied to the charging electrode. The polarity of the charge on the added drops can be changed allowing removal of charge from the trapped drop (by neutralization) and polarity reversal. The maximum amount of added charge is limited by repulsion of like charges between the drops in the trap. This charging scheme can aid in micromanipulation and the study of charged drops and particles using levitation. PMID:17580951

  20. Capillary Limit in a Loop Heat Pipe with Dual Evaporators

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Birur, Gajanana; Obenschain, Arthur F. (Technical Monitor)

    2002-01-01

    This paper describes a study on the capillary limit of a loop heat pipe (LHP) with two evaporators and two condensers. Both theoretical analysis and experimental investigation are conducted. Tests include heat load to one evaporator only, even heat loads to both evaporators and uneven heat load to both evaporators. Results show that after the capillary limit is exceeded, vapor will penetrate through the wick of the weaker evaporator and the compensation chamber (CC) of that evaporator will control the loop operating temperature regardless of which CC has been in control prior to the event Because the evaporator can tolerate vapor bubbles, the loop may continue to work and reach a new steady state at a higher operating temperature. The loop may even function with a modest increase in the heat load past the capillary limit With a heat load to only one evaporator, the capillary limit can be identified by rapid increases in the operating temperature and in the temperature difference between the evaporator and the CC. However, it is more difficult to tell when the capillary limit is exceeded if heat loads are applied to both evaporators. In all cases, the loop can recover by reducing the heat load to the loop.

  1. The continuous similarity model of bulk soil-water evaporation

    NASA Technical Reports Server (NTRS)

    Clapp, R. B.

    1983-01-01

    The continuous similarity model of evaporation is described. In it, evaporation is conceptualized as a two stage process. For an initially moist soil, evaporation is first climate limited, but later it becomes soil limited. During the latter stage, the evaporation rate is termed evaporability, and mathematically it is inversely proportional to the evaporation deficit. A functional approximation of the moisture distribution within the soil column is also included in the model. The model was tested using data from four experiments conducted near Phoenix, Arizona; and there was excellent agreement between the simulated and observed evaporation. The model also predicted the time of transition to the soil limited stage reasonably well. For one of the experiments, a third stage of evaporation, when vapor diffusion predominates, was observed. The occurrence of this stage was related to the decrease in moisture at the surface of the soil. The continuous similarity model does not account for vapor flow. The results show that climate, through the potential evaporation rate, has a strong influence on the time of transition to the soil limited stage. After this transition, however, bulk evaporation is independent of climate until the effects of vapor flow within the soil predominate.

  2. Automated single cell sorting and deposition in submicroliter drops

    NASA Astrophysics Data System (ADS)

    Salánki, Rita; Gerecsei, Tamás; Orgovan, Norbert; Sándor, Noémi; Péter, Beatrix; Bajtay, Zsuzsa; Erdei, Anna; Horvath, Robert; Szabó, Bálint

    2014-08-01

    Automated manipulation and sorting of single cells are challenging, when intact cells are needed for further investigations, e.g., RNA or DNA sequencing. We applied a computer controlled micropipette on a microscope admitting 80 PCR (Polymerase Chain Reaction) tubes to be filled with single cells in a cycle. Due to the Laplace pressure, fluid starts to flow out from the micropipette only above a critical pressure preventing the precise control of drop volume in the submicroliter range. We found an anomalous pressure additive to the Laplace pressure that we attribute to the evaporation of the drop. We have overcome the problem of the critical dropping pressure with sequentially operated fast fluidic valves timed with a millisecond precision. Minimum drop volume was 0.4-0.7 μl with a sorting speed of 15-20 s per cell. After picking NE-4C neuroectodermal mouse stem cells and human primary monocytes from a standard plastic Petri dish we could gently deposit single cells inside tiny drops. 94 ± 3% and 54 ± 7% of the deposited drops contained single cells for NE-4C and monocytes, respectively. 7.5 ± 4% of the drops contained multiple cells in case of monocytes. Remaining drops were empty. Number of cells deposited in a drop could be documented by imaging the Petri dish before and after sorting. We tuned the adhesion force of cells to make the manipulation successful without the application of microstructures for trapping cells on the surface. We propose that our straightforward and flexible setup opens an avenue for single cell isolation, critically needed for the rapidly growing field of single cell biology.

  3. Droplet evaporation on a horizontal substrate under gravity field by mesoscopic modeling.

    PubMed

    Xie, Chiyu; Zhang, Jianying; Bertola, Volfango; Wang, Moran

    2016-02-01

    The evaporation of water drop deposited on a horizontal substrate is investigated using a lattice Boltzmann method (LBM) for multiphase flows with a large-density ratio. To account for the variation of evaporation flux distribution along the drop interface, a novel evaporation scheme is introduced into the LBM framework, and validated by comparison with experimental data. We aim at discovering the effect of gravity on the evaporating drop in detail, and various evaporation conditions are considered as well as different wetting properties of the substrates. An effective diameter is introduced as an indicator of the critical drop size under which gravity is negligible. Our results show that such critical diameter is much smaller than the capillary length, which has been widely accepted as the critical size in previous and current works. The critical diameter is found to be almost independent of the evaporation conditions and the surface wettability. A correlation between this critical diameter and the capillary length is also proposed for easy use in applications. PMID:26562444

  4. Fluid Flow in An Evaporating Droplet

    NASA Technical Reports Server (NTRS)

    Hu, H.; Larson, R.

    1999-01-01

    Droplet evaporation is a common phenomenon in everyday life. For example, when a droplet of coffee or salt solution is dropped onto a surface and the droplet dries out, a ring of coffee or salt particles is left on the surface. This phenomenon exists not only in everyday life, but also in many practical industrial processes and scientific research and could also be used to assist in DNA sequence analysis, if the flow field in the droplet produced by the evaporation could be understood and predicted in detail. In order to measure the fluid flow in a droplet, small particles can be suspended into the fluid as tracers. From the ratio of gravitational force to Brownian force a(exp 4)(delta rho)(g)/k(sub B)T, we find that particle's tendency to settle is proportional to a(exp 4) (a is particle radius). So, to keep the particles from settling, the droplet size should be chosen to be in a range 0.1 -1.0 microns in experiments. For such small particles, the Brownian force will affect the motion of the particle preventing accurate measurement of the flow field. This problem could be overcome by using larger particles as tracers to measure fluid flow under microgravity since the gravitational acceleration g is then very small. For larger particles, Brownian force would hardly affect the motion of the particles. Therefore, accurate flow field could be determined from experiments in microgravity. In this paper, we will investigate the fluid flow in an evaporating droplet under normal gravity, and compare experiments to theories. Then, we will present our ideas about the experimental measurement of fluid flow in an evaporating droplet under microgravity.

  5. The interaction of evaporative and convective instabilities

    NASA Astrophysics Data System (ADS)

    Ozen, O.

    Evaporative convection arises in a variety of natural and industrial processes, such as drying of lakebeds, heat pipe technology and dry-eye syndrome. The phenomenon of evaporative convection leads to an interfacial instability where an erstwhile flat surface becomes undulated as a control variable, such as temperature drop, exceeds a critical value. This instability has been investigated by others assuming that the vapor phase is infinitely deep and passive, i.e. vapor fluid dynamics has been ignored. However, when we look at some engineering processes, such as distillation columns, heat pipes and drying technologies where phase change takes place we might imagine that the assumption of an infinitely deep vapor layer or at least that of a passive vapor is inappropriate. Previous work on convection in bilayer systems with no phase-change suggests that active vapor layers play a major role in determining the stability of an interface. Hence, for the case of convection with phase-change, we will address this issue and try to answer the question whether the infinitely deep and passive vapor layer is a valid assumption. We have also investigated, theoretically, the gravity and surface tension gradient-driven instabilities occurring during the evaporation of a liquid into its own vapor taking into account the fluid dynamics of both phases and the finiteness of the domains of each phase, i.e. the liquid and its vapor are assumed to be confined between two horizontal plates, and different heating arrangements are applied. The effects of fluid layer depths, the evaporation rate and the temperature gradient applied across the fluids on the stability of the interface are studied. The modes of the flow pattern are determined for each scenario. The physics of the instability are explained and a comparison is made with the results of similar, yet physically different problems.

  6. The evaporative fraction as a measure of surface energy partitioning

    SciTech Connect

    Nichols, W.E. ); Cuenca, R.H. )

    1990-01-01

    The evaporative fraction is a ratio that expresses the proportion of turbulent flux energy over land surfaces devoted to evaporation and transpiration (evapotranspiration). It has been used to characterize the energy partition over land surfaces and has potential for inferring daily energy balance information based on mid-day remote sensing measurements. The HAPEX-MOBILHY program's SAMER system provided surface energy balance data over a range of agricultural crops and soil types. The databases from this large-scale field experiment was analyzed for the purpose of studying the behavior and daylight stability of the evaporative fraction in both ideal and general meteorological conditions. Strong linear relations were found to exist between the mid-day evaporative fraction and the daylight mean evaporative fraction. Statistical tests however rejected the hypothesis that the two quantities were equal. The relations between the evaporative fraction and the surface soil moisture as well as soil moisture in the complete vegetation root zone were also explored.

  7. Evaporation rate and vapor pressure of selected polymeric lubricating oils.

    NASA Technical Reports Server (NTRS)

    Gardos, M. N.

    1973-01-01

    A recently developed ultrahigh-vacuum quartz spring mass sorption microbalance has been utilized to measure the evaporation rates of several low-volatility polymeric lubricating oils at various temperatures. The evaporation rates are used to calculate the vapor pressures by the Langmuir equation. A method is presented to accurately estimate extended temperature range evaporation rate and vapor pressure data for polymeric oils, incorporating appropriate corrections for the increases in molecular weight and the change in volatility of the progressively evaporating polymer fractions. The logarithms of the calculated data appear to follow linear relationships within the test temperature ranges, when plotted versus 1000/T. These functions and the observed effusion characteristics of the fluids on progressive volatilization are useful in estimating evaporation rate and vapor pressure changes on evaporative depletion.

  8. Evaporation rates of water from concentrated oil-in-water emulsions.

    PubMed

    Aranberri, I; Binks, B P; Clint, J H; Fletcher, P D I

    2004-03-16

    We have investigated the rate of water evaporation from concentrated oil-in-water (o/w) emulsions containing an involatile oil. Evaporation of the water continuous phase causes compression of the emulsion with progressive distortion of the oil drops and thinning of the water films separating them. Theoretically, the vapor pressure of water is sensitive to the interdroplet interactions, which are a function of the film thickness. Three main possible situations are considered. First, under conditions when the evaporation rate is controlled by mass transfer across the stagnant vapor phase, model calculations show that evaporation can, in principle, be slowed by repulsive interdroplet interactions. However, significant retardation requires very strong repulsive forces acting over large separations for typical emulsion drop sizes. Second, water evaporation may be limited by diffusion in the network of water films within the emulsion. In this situation, water loss by evaporation from the emulsion surface leads to a gradient in the water concentration (and in the water film thickness). Third, compression of the drops may lead to coalescence of the emulsion drops and the formation of a macroscopic oil film at the emulsion surface, which serves to prevent further water evaporation. Water mass-loss curves have been measured for silicone o/w emulsions stabilized by the anionic surfactant SDS as a function of the water content, the thickness of the stagnant vapor-phase layer, and the concentration of electrolyte in the aqueous phase, and the results are discussed in terms of the three possible scenarios just described. In systems with added salt, water evaporation virtually ceases before all the water present is lost, probably as a result of oil-drop coalescence resulting in the formation of a water-impermeable oil film at the emulsion surface. PMID:15835653

  9. Drop tube research

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.

    1992-01-01

    This report covers the activities performed in the Drop Tube Study which The University of Alabama in Huntsville designed, fabricated and performed various low gravity experiments in materials processing from November 1, 1991 through October 30, 1992. During the performance of this contract the utilization of these ground-based containerless processing facilities has been instrumental in providing the opportunity to determine the feasibility of performing a number of solidification experiments in a simulated space environment, without the expense of a space-based experiment. A number of periodic reports have been given to the TCOR during the course of this contract hence this final report is meant only to summarize the many activities performed and not redundantly cover materials already submitted.

  10. Evaporative Cooling of Antiprotons to Cryogenic Temperatures

    SciTech Connect

    Andresen, G. B.; Bowe, P. D.; Hangst, J. S.; Ashkezari, M. D.; Hayden, M. E.; Baquero-Ruiz, M.; Chapman, S.; Fajans, J.; Povilus, A.; So, C.; Wurtele, J. S.; Bertsche, W.; Butler, E.; Charlton, M.; Humphries, A.; Madsen, N.; Werf, D. P. van der; Wilding, D.; Cesar, C. L.; Lambo, R.

    2010-07-02

    We report the application of evaporative cooling to clouds of trapped antiprotons, resulting in plasmas with measured temperature as low as 9 K. We have modeled the evaporation process for charged particles using appropriate rate equations. Good agreement between experiment and theory is observed, permitting prediction of cooling efficiency in future experiments. The technique opens up new possibilities for cooling of trapped ions and is of particular interest in antiproton physics, where a precise CPT test on trapped antihydrogen is a long-standing goal.

  11. Evaporative cooling of antiprotons to cryogenic temperatures.

    PubMed

    Andresen, G B; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Bowe, P D; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Hangst, J S; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A; Hydomako, R; Jonsell, S; Kurchaninov, L; Lambo, R; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wilding, D; Wurtele, J S; Yamazaki, Y

    2010-07-01

    We report the application of evaporative cooling to clouds of trapped antiprotons, resulting in plasmas with measured temperature as low as 9 K. We have modeled the evaporation process for charged particles using appropriate rate equations. Good agreement between experiment and theory is observed, permitting prediction of cooling efficiency in future experiments. The technique opens up new possibilities for cooling of trapped ions and is of particular interest in antiproton physics, where a precise CPT test on trapped antihydrogen is a long-standing goal. PMID:20867439

  12. Normal evaporation of binary alloys

    NASA Technical Reports Server (NTRS)

    Li, C. H.

    1972-01-01

    In the study of normal evaporation, it is assumed that the evaporating alloy is homogeneous, that the vapor is instantly removed, and that the alloy follows Raoult's law. The differential equation of normal evaporation relating the evaporating time to the final solute concentration is given and solved for several important special cases. Uses of the derived equations are exemplified with a Ni-Al alloy and some binary iron alloys. The accuracy of the predicted results are checked by analyses of actual experimental data on Fe-Ni and Ni-Cr alloys evaporated at 1600 C, and also on the vacuum purification of beryllium. These analyses suggest that the normal evaporation equations presented here give satisfactory results that are accurate to within an order of magnitude of the correct values, even for some highly concentrated solutions. Limited diffusion and the resultant surface solute depletion or enrichment appear important in the extension of this normal evaporation approach.

  13. Determining the Inception and Magnitude of Subsurface Evaporation

    NASA Astrophysics Data System (ADS)

    Deol, P. K.; Heitman, J.; Amoozegar, A.; Clayton Field Study Team

    2011-12-01

    Evaporation from an initially wet soil occurs at the soil surface but further drying of surface soil with time results in the formation of a dry surface layer. At this stage, the evaporation front moves from the surface to the subsurface. This phenomenon occurs in a highly dynamic near-surface zone making it very challenging to know the location/depth of the evaporation front and to quantify the subsurface evaporation rate. Recent studies show that subsurface evaporation can be measured using a sensible heat balance approach by accounting for the latent heat flux originating below soil surface which is not taken into account in the traditional surface energy balance equation. The soil sensible energy balance approach has been successfully tested against mass balance for estimating evaporation under steady-state controlled lab conditions, as well as to a limited extent in the field. Limitations of the approach for field conditions include inability of instrumentation to quantify evaporation during the initial shift between surface and subsurface evaporation (i.e. when evaporation occurs at depths shallower than approximately 3 mm). The objectives of this study are to 1) find indicators of the change in the location of the evaporation front from surface to subsurface, and 2) test the sensible heat balance approach for quantifying evaporation from the inception of the subsurface evaporation zone. Recently introduced multi-needle heat pulse probes were used to make continuous soil temperature and thermal property measurements in the near-surface zone at the mm scale in a bare surface soil. Preliminary results from this investigation will be presented.

  14. Method and apparatus for flash evaporation of liquids

    DOEpatents

    Bharathan, Desikan

    1984-01-01

    A vertical tube flash evaporator for introducing a superheated liquid into a flash evaporation chamber includes a vertical inlet tube with a flared diffuser portion at its upper outlet end. A plurality of annular screens are positioned in axially spaced-apart relation to each other around the periphery of the vertical tube and below the diffuser portion thereof. The screens are preferably curved upward in a cup-shaped configuration. These flash evaporators are shown in an ocean thermal energy conversion unit designed for generating electric power from differential temperature gradients in ocean water. The method of use of the flash evaporators of this invention includes flowing liquid upwardly through the vertical tube into the diffuser where initial expansion and boiling occurs quite violently and explosively. Unvaporized liquid sheets and drops collide with each other to enhance surface renewal and evaporation properties, and liquid flowing over the outlet end of the diffuser falls onto the curved screens for further surface renewal and evaporation.

  15. Method and apparatus for flash evaporation of liquids

    DOEpatents

    Bharathan, D.

    1984-01-01

    A vertical tube flash evaporator for introducing a super-heated liquid into a flash evaporation chamber includes a vertical inlet tube with a flared diffuser portion at its upper outlet end. A plurality of annular screens are positioned in axially spaced-apart relation to each other around the periphery of the vertical tube and below the diffuser portion thereof. The screens are preferably curved upward in a cup-shaped configuration. These flash evaporators are shown in an ocean thermal energy conversion unit designed for generating electric power from differential temperature gradients in ocean water. The method of use of the flash evaporators of this invention includes flowing liquid upwardly through the vertical tube into the diffuser where initial expansion and boiling occurs quite violently and explosively. Unvaporized liquid sheets and drops collide with each other to enhance surface renewal and evaporation properties, and liquid flowing over the outlet end of the diffuser falls onto the curved screens for further surface renewal and evaporation.

  16. First drop dissimilarity in drop-on-demand inkjet devices

    SciTech Connect

    Famili, Amin; Palkar, Saurabh A.; Baldy, William J. Jr.

    2011-01-15

    As inkjet printing technology is increasingly applied in a broader array of applications, careful characterization of its method of use is critical due to its inherent sensitivity. A common operational mode in inkjet technology known as drop-on-demand ejection is used as a way to deliver a controlled quantity of material to a precise location on a target. This method of operation allows ejection of individual or a sequence (burst) of drops based on a timed trigger event. This work presents an examination of sequences of drops as they are ejected, indicating a number of phenomena that must be considered when designing a drop-on-demand inkjet system. These phenomena appear to be driven by differences between the first ejected drop in a burst and those that follow it and result in a break-down of the linear relationship expected between driving amplitude and drop mass. This first drop, as quantified by high-speed videography and subsequent image analysis, can be different in morphology, trajectory, velocity, and volume from subsequent drops within a burst. These findings were confirmed orthogonally by both volume and mass measurement techniques which allowed quantitation down to single drops.

  17. 40 CFR 86.143-96 - Calculations; evaporative emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Calculations; evaporative emissions. 86.143-96 Section 86.143-96 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Complete Heavy-Duty Vehicles; Test Procedures § 86.143-96 Calculations; evaporative emissions. (a)...

  18. 40 CFR 86.1243-96 - Calculations; evaporative emissions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 20 2013-07-01 2013-07-01 false Calculations; evaporative emissions. 86.1243-96 Section 86.1243-96 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Evaporative Emission Test Procedures for...

  19. 40 CFR 86.1243-96 - Calculations; evaporative emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Calculations; evaporative emissions. 86.1243-96 Section 86.1243-96 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Evaporative Emission Test Procedures for...

  20. Spacesuit Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Hodgson, Ed; Izenso, Mike; Chan, Weibo; Cupples, Scott

    2011-01-01

    For decades advanced spacesuit developers have pursued a regenerable, robust non-venting system for heat rejection. Toward this end, this paper investigates linking together two previously developed technologies, namely NASA's Spacesuit Water Membrane Evaporator (SWME), and Creare's lithium chloride Heat Pump Radiator (HPR). Heat from a liquid cooled garment is transported to SWME that provides cooling through evaporation. The SEAR is evacuated at the onset of operations and thereafter, the water vapor absorption rate of the HPR maintains a low pressure environment for the SWME to evaporate effectively. This water vapor captured by solid LiCl in the HPR with a high enthalpy of absorption, results in sufficient temperature lift to reject most of the heat to space by radiation. After the sortie, the HPR would be heated up in a regenerator to drive off and recover the absorbed evaporant. A one-fourth scale prototype was built and tested in vacuum conditions at a sink temperature of 250 K. The HPR was able to stably reject 60 W over a 7-hour period. A conceptual design of a full-scale radiator is proposed. Excess heat rejection above 240 W would be accomplished through venting of the evaporant. Loop closure rates were predicted for various exploration environment scenarios.

  1. An evaporation based digital microflow meter

    NASA Astrophysics Data System (ADS)

    Nie, C.; Frijns, A. J. H.; Mandamparambil, R.; Zevenbergen, M. A. G.; den Toonder, J. M. J.

    2015-11-01

    In this work, we present a digital microflow meter operating in the range 30-250 nl min-1 for water. The principle is based on determining the evaporation rate of the liquid via reading the number of wetted pore array structures in a microfluidic system, through which continuous evaporation takes place. A proof-of-principle device of the digital flow meter was designed, fabricated, and tested. The device was built on foil-based technology. In the proof-of-principle experiments, good agreement was found between set flow rates and the evaporation rates estimated from reading the number of wetted pore structures. The measurement range of the digital flow meter can be tuned and extended in a straightforward manner by changing the pore structure of the device.

  2. Development of a new testing equipment that combines the working principles of both the split Hopkinson bar and the drop weight testers.

    PubMed

    Adas, Rateb; Haiba, Majed

    2016-01-01

    In the current work, a new high strain rate tensile testing equipment is proposed. The equipment uses a pendulum device to generate an impact load and a three-bar mechanism to bring that load to act upon a specially designed specimen. As the standard impact testing apparatus uses pendulum device and the well-known SHB high strain rate tester adopts the above-mentioned mechanism, the introduced equipment can be dealt with as an impact apparatus in which the base that supports the V-shape specimen is replaced with the three-bar configuration that the traditional SHB uses. In order to demonstrate the applicability of the new tester, virtual design tools were used to determine the most appropriate configuration for it. Then, a detailed design was created, and a full-scale prototype was produced, calibrated, instrumented and tested. The obtained results demonstrate that the new tester is capable of axially straining steel specimens up to failure at a maximum rate of about 250 s(-1), which is reasonable when compared with a more established high strain rate testers. PMID:27504253

  3. Flow rate/pressure drop data gathered from testing a sample of the Space Shuttle Strain Isolation Pad (SIP): Effects of ambient pressure combined with tension and compression conditions

    NASA Technical Reports Server (NTRS)

    Springfield, R. D.; Lawing, P. L.

    1983-01-01

    Tests were conducted on a sample of strain isolation pad (SIP) typical of that used in the shuttle orbiter thermal protection system to determine the characteristics of SIP internal flow. Data obtained were pressure drop as a function of flow rate for a range of ambient pressures representing various points along the Shuttle trajectory and for stretched and compressed conditions of the SIP. Flow was in the direction of the weave parallel to most of the fibers. The data are plotted in several standard engineering formats in order to be of maximum utility to the user. In addition to providing support to the Space Shuttle Program, these data are a source of experimental information on flow through fiberous (rather than the more usual sand bed type) porous media.

  4. Do Bacterial Symbionts Govern Aphid's Dropping Behavior?

    PubMed

    Lavy, Omer; Sher, Noa; Malik, Assaf; Chiel, Elad

    2015-06-01

    Defensive symbiosis is amongst nature's most important interactions shaping the ecology and evolution of all partners involved. The pea aphid, Acyrthosiphon pisum Harris (Hemiptera: Aphididae), harbors one obligatory bacterial symbiont and up to seven different facultative symbionts, some of which are known to protect the aphid from pathogens, natural enemies, and other mortality factors. Pea aphids typically drop off the plant when a mammalian herbivore approaches it to avoid incidental predation. Here, we examined whether bacterial symbionts govern the pea aphid dropping behavior by comparing the bacterial fauna in dropping and nondropping aphids of two A. pisum populations, using two molecular techniques: high-throughput profiling of community structure using 16 S reads sequenced on the Illumina platform, and diagnostic polymerase chain reaction (PCR). We found that in addition to the obligatory symbiont, Buchnera aphidicola, the tested colonies of A. pisum harbored the facultative symbionts Serratia symbiotica, Regiella insecticola and Rickettsia, with no significant differences in infection proportions between dropping and nondropping aphids. While S. symbiotica was detected by both techniques, R. insecticola and Rickettsia could be detected only by diagnostic PCR. We therefore conclude that A. pisum's dropping behavior is not affected by its bacterial symbionts and is possibly affected by other factors. PMID:26313964

  5. Evaporation control research, 1955-58

    USGS Publications Warehouse

    Cruse, Robert R.; Harbeck, Guy Earl

    1960-01-01

    One hundred fifty-two compounds and compositions of matter were screened as potential evaporation retardants. The homologous straight-chain fatty alkanols are considered the best materials for retardants. Several methods of application of the alkanols to the reservoir surface were investigated. Although wick-type drippers for the application of liquids and cage rafts for the application of solids appear to be the most promising methods from an economic standpoint, both methods have serious disadvantages. Considerable study was given to reducing biochemical oxidation of the evaporation retardants. Copper in several forms was found adequate as a bacteriostatic agent but posed a potential hazard because of its toxicity. Many other bactericides that were tested were also toxic. Two sets of large-scale field tests have been completed and several others are still in progress. On the larger reservoirs, the reduction of evaporation was not more than 20 percent under the prevailing conditions and the application procedure used. Three major practical problems remain; namely, the effects and action of wind on the monofilm, the effects of biochemical oxidation, and the most effective method of application. Fundamental problems remaining include the effects of various impurities, and the composition of the best evaporation retardant; the long-range effects of monofilms on the limnology of a reservoir, including the transfer of oxygen and carbon dioxide; toxicological aspects of all components of any evaporation-retardant composition, plus toxicology of any composition chosen for large-scale use; and further studies of the calorimetry and thermodynamics involved in the mechanism of evaporation and its reduction by a monofilm.

  6. Method of evaporation

    NASA Technical Reports Server (NTRS)

    Dufresne, Eugene R.

    1987-01-01

    Liquids, such as juices, milk, molten metal and the like are concentrated by forming uniformly-sized, small droplets in a precision droplet forming assembly and deploying the droplets in free fall downwardly as a central column within an evacuated column with cool walls. A portion of the solvent evaporates. The vapor flows to the wall, condenses, and usually flows down the wall as a film to condensate collector and drain. The vertical column of freely falling droplets enters the splash guard. The condensate can be collected, sent to other towers or recycled.

  7. Semifluorinated Alkane Eye Drops for Treatment of Dry Eye Disease—A Prospective, Multicenter Noninterventional Study

    PubMed Central

    Scherer, Dieter; Krösser, Sonja; Beckert, Michael; Cursiefen, Claus; Kaercher, Thomas

    2015-01-01

    Abstract Purpose: Evaporation of the tear film is heavily discussed as one core reason for dry eye disease (DED). Subsequently, new artificial tear products are developed that specifically target this pathomechanism. Perfluorohexyloctane (F6H8, NovaTears®) from the family of semifluorinated alkanes is a novel substance that has been approved as a medical device, as a nonblurring wetting agent for the ocular surface. Methods: Thirty patients with hyperevaporative dry eye received F6H8 during a prospective, multicenter, observational 6-week study. Patients were advised to apply 1 drop 4 times daily in both eyes. Parameters assessed included best corrected visual acuity, intraocular pressure, Schirmer I test, tear fluid, tear film breakup time (TFBUT), corneal staining, meibum secretion, and Ocular Surface Disease Index (OSDI©). Results: From the 30 patients recruited, 25 completed the trial per protocol. Four patients discontinued F6H8 and 1 patient did not present for follow-up. F6H8 treatment led to significant reduction of corneal staining and significant increase of Schirmer I and TFBUT. In addition, OSDI score dropped significantly from a mean of 55 (±23.0) to 34 (±22.4). Visual acuity and ocular pressure did not change. Conclusions: This prospective observational study shows significant beneficial effects in patients suffering from evaporative DED, using F6H8 in all the relevant parameters tested. The decrease of the OSDI by a mean of 21 points was particularly remarkable and clearly exceeds minimal, clinical important differences for mild or moderate and severe disease. Overall, F6H8 (NovaTears) seems to be safe and effective in treating mild to moderate hyperevaporative DED. PMID:26296040

  8. Large amplitude drop shape oscillations

    NASA Technical Reports Server (NTRS)

    Trinh, E. H.; Wang, T. G.

    1982-01-01

    An experimental study of large amplitude drop shape oscillation was conducted in immiscible liquids systems and with levitated free liquid drops in air. In liquid-liquid systems the results indicate the existence of familiar characteristics of nonlinear phenomena. The resonance frequency of the fundamental quadrupole mode of stationary, low viscosity Silicone oil drops acoustically levitated in water falls to noticeably low values as the amplitude of oscillation is increased. A typical, experimentally determined relative frequency decrease of a 0.5 cubic centimeters drop would be about 10% when the maximum deformed shape is characterized by a major to minor axial ratio of 1.9. On the other hand, no change in the fundamental mode frequency could be detected for 1 mm drops levitated in air. The experimental data for the decay constant of the quadrupole mode of drops immersed in a liquid host indicate a slight increase for larger oscillation amplitudes. A qualitative investigation of the internal fluid flows for such drops revealed the existence of steady internal circulation within drops oscillating in the fundamental and higher modes. The flow field configuration in the outer host liquid is also significantly altered when the drop oscillation amplitude becomes large.

  9. The dropped big toe.

    PubMed

    Satku, K; Wee, J T; Kumar, V P; Ong, B; Pho, R W

    1992-03-01

    Surgical procedures for exposure of the upper third of the fibula have been known to cause weakness of the long extensor of the big toe post-operatively. The authors present three representative cases of surgically induced dropped big toe. From cadaveric dissection, an anatomic basis was found for this phenomenon. The tibialis anterior and extensor digitorum longus muscles have their origin at the proximal end of the leg and receive their first motor innervation from a branch that arises from the common peroneal or deep peroneal nerve at about the level of the neck of the fibula. However, the extensor hallucis longus muscle originates in the middle one-third of the leg and the nerves innervating this muscle run a long course in close proximity to the fibula for up to ten centimeters from a level below the neck of the fibula before entering the muscle. Surgical intervention in the proximal one-third of the fibula just distal to the origin of the first motor branch to the tibialis anterior and extensor digitorum longus muscles carries a risk of injury to the nerves innervating the extensor hallucis longus. PMID:1519891

  10. Evaporation of pure liquids with increased viscosity in a falling film evaporator

    NASA Astrophysics Data System (ADS)

    Weise, Felix; Scholl, Stephan

    2009-05-01

    The present study investigated fluid dynamics and heat transfer of viscous pure liquids in a falling film evaporator. This is of special benefit as it avoids mass transfer effects on the evaporation behaviour. Experiments at a single-tube glass falling film evaporator were conducted. It allowed a full-length optical film observation with a high-speed camera. Additionally the evaporator was equipped with a slotted weir distribution device. Test fluids provided viscosities ranging from μ = 0.3 to 41 mPa s. The Reynolds number was between 0.7 and 1,930. Surface evaporation and the transition to nucleate boiling were studied to gain information about the film stability at maximum wall superheat. A reliable database for laminar and laminar-wavy viscous single component films was created. The experimental results show a significant enhancement in the wave development due to the film distribution. A wavy flow with different wave velocities was superposed to the film in each liquid load configuration without causing a film breakdown or dry spots on the evaporator tube. It was found that nucleate boiling can be allowed without causing film instabilities over a significant range of wall superheat.

  11. Reservoir evaporation in Texas, USA

    NASA Astrophysics Data System (ADS)

    Wurbs, Ralph A.; Ayala, Rolando A.

    2014-03-01

    The role of reservoir surface evaporation in river/reservoir water budgets and water management is explored using a modeling system that combines historical natural hydrology with current conditions of water resources development and management. The long-term mean evaporation from the 3415 reservoirs in the Texas water rights permit system is estimated to be 7.53 billion m3/year, which is equivalent to 61% of total agricultural or 126% of total municipal water use in the state during the year 2010. Evaporation varies with the hydrologic conditions governing reservoir surface areas and evaporation rates. Annual statewide total evaporation volumes associated with exceedance probabilities of 75%, 50%, and 25% are 7.07, 7.47, and 7.95 billion m3/year, respectively. Impacts of evaporation are greatest during extended severe droughts that govern water supply capabilities.

  12. Octopus-shaped Instabilities of Evaporating Droplets

    NASA Astrophysics Data System (ADS)

    Murisic, Nebojsa; Kondic, Lou; Gotkis, Yehiel; Ivanov, Igor

    2006-11-01

    We report on curious phenomena recorded recently during spreading of evaporating isopropyl alcohol droplets on silicon wafer surfaces. Novel ``octopus''-shaped instabilities were noticed appearing close to the contact line. In addition to our desire to understand the instability, a motivation for this study is the fact that the region close to the contact line carries significant amounts of solid residue which can deteriorate electrical and other properties of the semiconductor devices. After presenting the experimental results, we discuss a lubrication-based mathematical model describing spreading of volatile drops. Through linear stability analysis and numerical simulations, we show that essential factors influencing occurrence of ``octopus''-shaped instabilities include volatility of liquid, and thermal conductivity of both liquid and solid. see http://m.njit.edu/~kondic/thinfilms/octopi.html.

  13. A generalized complementary relationship between actual and potential evaporation defined by a reference surface temperature

    NASA Astrophysics Data System (ADS)

    Aminzadeh, Milad; Roderick, Michael L.; Or, Dani

    2016-01-01

    The definition of potential evaporation remains widely debated despite its centrality for hydrologic and climatic models. We employed an analytical pore-scale representation of evaporation from terrestrial surfaces to define potential evaporation using a hypothetical steady state reference temperature that is common to both air and evaporating surface. The feedback between drying land surfaces and overlaying air properties, central in the Bouchet (1963) complementary relationship, is implicitly incorporated in the hypothetical steady state where the sensible heat flux vanishes and the available energy is consumed by evaporation. Evaporation rates predicted based on the steady state reference temperature hypothesis were in good agreement with class A pan evaporation measurements suggesting that evaporation from pans occurs with negligible sensible heat flux. The model facilitates a new generalization of the asymmetric complementary relationship with the asymmetry parameter b analytically predicted for a wide range of meteorological conditions with initial tests yielding good agreement between measured and predicted actual evaporation.

  14. Viscosity Measurement Using Drop Coalescence in Microgravity

    NASA Technical Reports Server (NTRS)

    Antar, Basil N.; Ethridge, Edwin C.; Maxwell, Daniel; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    We present in here validation studies of a new method for application in microgravity environment which measures the viscosity of highly viscous undercooled liquids using drop coalescence. The method has the advantage of avoiding heterogeneous nucleation at container walls caused by crystallization of undercooled liquids during processing. Homogeneous nucleation can also be avoided due to the rapidity of the measurement using this method. The technique relies on measurements from experiments conducted in near zero gravity environment as well as highly accurate analytical formulation for the coalescence process. The viscosity of the liquid is determined by allowing the computed free surface shape relaxation time to be adjusted in response to the measured free surface velocity for two coalescing drops. Results are presented from two sets of validation experiments for the method which were conducted on board aircraft flying parabolic trajectories. In these tests the viscosity of a highly viscous liquid, namely glycerin, was determined at different temperatures using the drop coalescence method described in here. The experiments measured the free surface velocity of two glycerin drops coalescing under the action of surface tension alone in low gravity environment using high speed photography. The liquid viscosity was determined by adjusting the computed free surface velocity values to the measured experimental data. The results of these experiments were found to agree reasonably well with the known viscosity for the test liquid used.

  15. Hanging drop crystal growth apparatus

    NASA Technical Reports Server (NTRS)

    Naumann, Robert J. (Inventor); Witherow, William K. (Inventor); Carter, Daniel C. (Inventor); Bugg, Charles E. (Inventor); Suddath, Fred L. (Inventor)

    1990-01-01

    This invention relates generally to control systems for controlling crystal growth, and more particularly to such a system which uses a beam of light refracted by the fluid in which crystals are growing to detect concentration of solutes in the liquid. In a hanging drop apparatus, a laser beam is directed onto drop which refracts the laser light into primary and secondary bows, respectively, which in turn fall upon linear diode detector arrays. As concentration of solutes in drop increases due to solvent removal, these bows move farther apart on the arrays, with the relative separation being detected by arrays and used by a computer to adjust solvent vapor transport from the drop. A forward scattering detector is used to detect crystal nucleation in drop, and a humidity detector is used, in one embodiment, to detect relative humidity in the enclosure wherein drop is suspended. The novelty of this invention lies in utilizing angular variance of light refracted from drop to infer, by a computer algorithm, concentration of solutes therein. Additional novelty is believed to lie in using a forward scattering detector to detect nucleating crystallites in drop.

  16. Gas Pressure-Drop Experiment

    ERIC Educational Resources Information Center

    Luyben, William L.; Tuzla, Kemal

    2010-01-01

    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…

  17. Tank 26F-2F Evaporator Study

    SciTech Connect

    Adu-Wusu, K.

    2012-12-19

    Tank 26F supernate sample was sent by Savannah River Remediation to Savannah River National Laboratory for evaporation test to help understand the underlying cause of the recent gravity drain line (GDL) pluggage during operation of the 2F Evaporator system. The supernate sample was characterized prior to the evaporation test. The evaporation test involved boiling the supernate in an open beaker until the density of the concentrate (evaporation product) was between 1.4 to 1.5 g/mL. It was followed by filtering and washing of the precipitated solids with deionized water. The concentrate supernate (or concentrate filtrate), the damp unwashed precipitated solids, and the wash filtrates were characterized. All the precipitated solids dissolved during water washing. A semi-quantitative X-ray diffraction (XRD) analysis on the unwashed precipitated solids revealed their composition. All the compounds with the exception of silica (silicon oxide) are known to be readily soluble in water. Hence, their dissolution during water washing is not unexpected. Even though silica is a sparingly water-soluble compound, its dissolution is also not surprising. This stems from its small fraction in the solids as a whole and also its relative freshness. Assuming similar supernate characteristics, flushing the GDL with water (preferably warm) should facilitate dissolution and removal of future pluggage events as long as build up/aging of the sparingly soluble constituent (silica) is limited. On the other hand, since the amount of silica formed is relatively small, it is quite possible dissolution of the more soluble larger fraction will cause disintegration or fragmentation of the sparingly soluble smaller fraction (that may be embedded in the larger soluble solid mass) and allow its removal via suspension in the flushing water.

  18. Binary drop coalescence in liquids

    NASA Astrophysics Data System (ADS)

    Kim, Jungyong

    Experiments on binary drop collisions within an index-matched liquid were conducted for Weber numbers (We) of 1-50 and collision angles of 15-80° below the horizontal. Drop pairs of water/glycerin mixture were injected into silicone oil and, due to gravitational effects, traveled on downward trajectories before colliding. A dual-field high-speed PIV measurement system was employed to quantify drop trajectories and overall collision conditions while simultaneously examining detailed velocity fields near the collision interface. In the We range examined, for equal size drops, both rebounding and coalescing behavior occurred. The drops coalesced for We > 10 and rebounded for We < 10, and this boundary was found to be insensitive to collision angle. Coalescence was found to result from a combination of vortical flow within drops and strong drop deformation characteristic of higher We. Flow through the centers of opposing ring vortices, strengthened by drop deformation, enhanced drainage of the thin film in the impact region, leading to film rupture and coalescence. The collision angle affected the eventual location of film rupture, with the rupture location moving higher in the thin film region as the collision angle increased. The film rupture location correlated closely with the location of maximum downward velocity in the thin film. The time between collision and rupture increases with We until We = 30. For We > 30, the time decreases as We increases. Unequal size drop collisions with drop size ratios (Ds/D L) of 0.7 and 0.5 were also examined. Coalescence occurs above We* = 11 similar to equal size drops. As drop size ratio decreases, the intervening film deforms more. If the velocity ratio uL/u s < 1, the deformed interface becomes flat before coalescence. The rupture location varies due to the asymmetry of the drops. As collision offset increases (B > 0), the film rupture time is shortened and mixing of the fluid from both drops is enhanced after coalescence

  19. Out-of-tank evaporator demonstration: Tanks focus area

    SciTech Connect

    1998-11-01

    Approximately 100 million gal of liquid waste is stored in underground storage tanks (UST)s at the Hanford Site, Idaho National Engineering and Environmental Laboratory (INEEL), Savannah River Site (SRS), and Oak Ridge Reservation (ORR). This waste is radioactive with a high salt content. The US Department of Energy (DOE) wants to minimize the volume of radioactive liquid waste in USTs by removing the excess water. This procedure conserves tank space; lowers the cost of storage; and reduces the volume of wastes subsequently requiring separation, immobilization, and disposal. The Out-of-Tank Evaporator Demonstration (OTED) was initiated to test a modular, skid-mounted evaporator. A mobile evaporator system manufactured by Delta Thermal Inc. was selected. The evaporator design was routinely used in commercial applications such as concentrating metal-plating wastes for recycle and concentrating ethylene glycol solutions. In FY 1995, the skid-mounted evaporator system was procured and installed in an existing ORNL facility (Building 7877) with temporary shielding and remote controls. The evaporator system was operational in January 1996. The system operated 24 h/day and processed 22,000 gal of Melton Valley Storage Tank (MVST) supernatant. The distillate contained essentially no salts or radionuclides. Upon completion of the demonstration, the evaporator underwent decontamination testing to illustrate the feasibility of hands-on maintenance and potential transport to another DOE facility. This report describes the process and the evaporator, its performance at ORNL, future plans, applications of this technology, cost estimates, regulatory and policy considerations, and lessons learned.

  20. Magnetic control of Leidenfrost drops.

    PubMed

    Piroird, Keyvan; Clanet, Christophe; Quéré, David

    2012-05-01

    We show how a magnetic field can influence the motion of a paramagnetic drop made of liquid oxygen in a Leidenfrost state on solids at room temperature. It is demonstrated that the trajectory can be modified in both direction and velocity and that the results can be interpreted in terms of classical mechanics as long as the drop does not get too close to the magnet. We study the deviation and report that it can easily overcome 180∘ and even diverge under certain conditions, leading to situations where a drop gets captured. In the vicinity of the magnet, another type of trapping is observed, due to the deformation of the drop in this region, which leads to a strong energy dissipation. Conversely, drops can be accelerated by moving magnets (slingshot effect). PMID:23004866

  1. Evaporative precooling unit

    SciTech Connect

    Rogers, A.R.

    1988-03-15

    In combination with a refrigeration unit, an evaporative heat exchange unit for precooling an air stream traveling toward and over the condensing coil of the refrigeration unit is described. The heat exchange unit includes: (a) a frame, (b) a porous heat transfer pad mounted in the frame; (c) nozzle means carried on the frame for directing a spray mist forwardly of the heat transfer pad, the spray mist emitted from the nozzle means initially traveling in a direction of travel such that the mist will not contact the porous heat transfer pad; (d) means mounted on the frame for causing the turbulent intermixing of the air stream with the spray mist prior to the air stream passing through the porous heat transfer pad; and (e) means for controlling the quantity of water emitted by the nozzle means such that substantially all of the spray mist is intermixed with the air stream prior to the air stream passing through the heat transfer pad.

  2. Turkish Undergraduates' Misconceptions of Evaporation, Evaporation Rate, and Vapour Pressure

    ERIC Educational Resources Information Center

    Canpolat, Nurtac

    2006-01-01

    This study focused on students' misconceptions related to evaporation, evaporation rate, and vapour pressure. Open-ended diagnostic questions were used with 107 undergraduates in the Primary Science Teacher Training Department in a state university in Turkey. In addition, 14 students from that sample were interviewed to clarify their written…

  3. How surfactants influence evaporation-driven flows

    NASA Astrophysics Data System (ADS)

    Liepelt, Robert; Marin, Alvaro; Rossi, Massimiliano; Kähler, Christian J.

    2014-11-01

    Capillary flows appear spontaneously in sessile evaporating drops and give rise to particle accumulation around the contact lines, commonly known as coffee-stain effect (Deegan et al., Nature, 1997). On the other hand, out-of-equilibrium thermal effects may induce Marangoni flows in the droplet's surface that play an important role in the flow patterns and in the deposits left on the substrate. Some authors have argued that contamination or the presence of surfactants might reduce or eventually totally annul the Marangoni flow (Hu & Larson, J. Phys. Chem. B, 2006). On the contrary, others have shown an enhancement of the reverse surface flow (Sempels et al., Nat. Commun., 2012). In this work, we employ Astigmatic Particle Tracking Velocimetry (APTV) to obtain the 3D3C evaporation-driven flow in both bulk and droplet's surface, using surfactants of different ionic characters and solubility. Our conclusions lead to a complex scenario in which different surfactants and concentrations yield very different surface-flow patterns, which eventually might influence the colloidal deposition patterns.

  4. The evaporative gas turbine (EGT) cycle

    SciTech Connect

    Horlock, J.H.

    1998-04-01

    Humidification of the flow through a gas turbine has been proposed in a variety of forms. The STIG plant involves the generation of steam by the gas turbine exhaust in a heat recovery steam generator (HRSG), and its injection into or downstream of the combustion chamber. This increases the mass flow through the turbine and the power output from the plant, with a small increase in efficiency. In the evaporative gas turbine (or EGT) cycle, water is injected in the compressor discharge in a regenerative gas turbine cycle (a so-called CBTX plant--compressor [C], burner [B], turbine [T], heat exchanger [X]); the air is evaporatively cooled before it enters the heat exchanger. While the addition of water increases the turbine mass flow and power output, there is also apparent benefit in reducing the temperature drop in the exhaust stack. In one variation of the basic EGT cycle, water is also added downstream of the evaporative aftercooler, even continuously in the heat exchanger. There are several other variations on the basic cycle (e.g., the cascaded humidified advanced turbine [CHAT]). The present paper analyzes the performance of the EGT cycle. The basic thermodynamics are first discussed, and related to the cycle analysis of a dry regenerative gas turbine plant. Subsequently some detailed calculations of EGT cycles are presented. The main purpose of the work is to seek the optimum pressure ratio in the EGT cycle for given constraints (e.g., fixed maximum to minimum temperature). It is argued that this optimum has a relatively low value.

  5. Coupling dynamic blow down and pool evaporation model for LNG.

    PubMed

    Woodward, John L

    2007-02-20

    Treating the dynamic effects of accidental discharges of liquefied natural gas (LNG) is important for realistic predictions of pool radius. Two phenomena have important influence on pool spread dynamics, time-varying discharge (blow down) and pool ignition. Time-varying discharge occurs because a punctured LNG tanker or storage tank drains with a decreasing liquid head and decreasing head-space pressure. Pool ignition increases the evaporation rate of a pool and consequently decreases the ultimate pool area. This paper describes an approach to treat these phenomena in a dynamic pool evaporation model. The pool evaporation model developed here has two separate regimes. Early in the spill, momentum forces dominate and the pool spreads independently of pool evaporation rate and the corresponding heat transfer rate. After the average pool depth drops below a minimum value, momentum forces are largely dissipated and the thin edges of the pool completely evaporate, so pool area is established by the heat transfer rate. The maximum extent of a burning pool is predicted to be significantly less than that of an unignited pool because the duration of the first regime is reduced by higher heat transfer rates. The maximum extent of an LNG pool is predicted to be larger upon accounting for blow down compared with using a constant average discharge rate. However, the maximum pool extent occurs only momentarily before retreating. PMID:17184912

  6. Instant freezing of impacting wax drops

    NASA Astrophysics Data System (ADS)

    Ponomarenko, Alexandre; Virot, Emmanuel; Rubinstein, Shmuel

    2015-11-01

    We present the impact of hot liquid drops of wax on surfaces whose temperature is below the solidifying temperature of the drops. During the fall the drops remain mostly liquid, but upon impact, their temperature quickly decreases resulting in the solidification of the drop. Depending on the impact energy, drops size and the temperature difference between the drop and the surface this results in plethora of solid shapes: simple lenses, triangular drops, spherical caps and popped popcorn shapes.

  7. Evaporation from the shallow Lake Massaciuccoli (Tuscany, Italy) studied using stable isotopes and evaporation pan data

    NASA Astrophysics Data System (ADS)

    Baneschi, I.; Gonfiantini, R.; Guidi, M.

    2009-04-01

    Oxygen and hydrogen isotope variations monitored in Lake Massaciuccoli (7 km2, 2 m deep, seasonally variable water level) during summer 2008, were compared with those observed in a Class A evaporation pan (diameter 120.6 cm, depth 25.4 cm) placed on the lake eastern shore. Air temperature, pressure, relative humidity, wind speed and direction, solar radiation, water temperature in the lake and the pan were also measured. The pluviometer indicated that no precipitation occurred during the study period. The pan was initially filled with groundwater up to the level of 19.2 cm (219 L), depleted in heavy isotopes with respect to tha lake water. Sodium chloride was added up to the concentration of 1 g×L-1, which is assumed do not affect significantly the evaporation rate till the water volume is reduced to less than 10 %. The Cl- concentration was used to provide an estimation of the evaporated water fraction, in addition to the micrometer measuring the water level variations. The pan water was sampled every 2-3 days and Cl- and stable isotopes determined. The set of stable isotope and evaporation data enabled us to compute the parameters governing the evaporation process and the isotopic exchanges with the atmospheric moisture, according to the procedure proposed by Gonfiantini (1986). The values were applied to test three working hypotheses of water balance of Lake Massaciuccoli: (i) surface inflow and outflow of liquid water are negligible and only evaporation is important; (ii) the inflow is negligible and outflow and evaporation are both significant; (iii) the three terms of balance are all important but the losses by evaporation and outflow exceed inflow (as the lake water level was decreasing). Water exchanges with groundwater are considered negligible. The best agreement between lake and pan data was obtained with the second hypothesis, for which the fraction of water removed by evaporation was estimated to be about 40 % ot he total water losses. This residual

  8. Electrokinetics of isolated electrified drops.

    PubMed

    Pillai, Rohit; Berry, Joseph D; Harvie, Dalton J E; Davidson, Malcolm R

    2016-04-14

    Using a recently developed multiphase electrokinetic model, we simulate the transient electrohydrodynamic response of a liquid drop containing ions, to both small and large values of electric field. The temporal evolution is found to be governed primarily by two dimensionless groups: (i) Ohnesorge number (Oh), a ratio of viscous to inertio-capillary effects, and (ii) inverse dimensionless Debye length (κ), a measure of the diffuse regions of charge that develop in the drop. The effects of dielectric polarization dominate at low Oh, while effects of separated charge gain importance with increase in Oh. For small values of electric field, the deformation behaviour of a drop is shown to be accurately described by a simple analytical expression. At large electric fields, the drops are unstable and eject progeny drops. Depending on Oh and κ this occurs via dripping or jetting; the regime transitions are shown by a Oh-κ phase map. In contrast to previous studies, we find universal scaling relations to predict size and charge of progeny drops. Our simulations suggest charge transport plays a significant role in drop dynamics for 0.1 ≤ Oh ≤ 10, a parameter range of interest in microscale flows. PMID:26954299

  9. Evaporation and skin penetration characteristics of mosquito repellent formulations

    SciTech Connect

    Reifenrath, W.G.; Hawkins, G.S.; Kurtz, M.S.

    1989-03-01

    Formulations of the mosquito repellent N,N-diethyl-3-methylbenzamide (deet) in combination with a variety of additives were developed to control repellent evaporation and percutaneous penetration. Deet was also formulated with the repellent dimethyl phthalate to study the interaction of the two compounds on the skin. The evaporation and penetration processes were evaluated on whole and split-thickness pig skin using radiolabeled repellents with an in vitro apparatus. Under essentially still air and air flow conditions, one of the deet formulations resulted in significantly reduced total evaporation and percutaneous penetration of deet as compared to unformulated repellent. When deet and dimethyl phthalate were combined, neither repellent affected the total amount of evaporation and penetration of the other compound. However, initial percutaneous penetration and evaporation rates were slightly less and decayed less rapidly than when both chemicals were tested separately at the same dose. These results indicated a degree of competition of the two compounds for the same avenues of loss.

  10. Vacuum flash evaporated polymer composites

    DOEpatents

    Affinito, John D.; Gross, Mark E.

    1997-01-01

    A method for fabrication of polymer composite layers in a vacuum is disclosed. More specifically, the method of dissolving salts in a monomer solution, vacuum flash evaporating the solution, condensing the flash evaporated solution as a liquid film, and forming the condensed liquid film into a polymer composite layer on a substrate is disclosed.

  11. Vacuum flash evaporated polymer composites

    DOEpatents

    Affinito, J.D.; Gross, M.E.

    1997-10-28

    A method for fabrication of polymer composite layers in a vacuum is disclosed. More specifically, the method of dissolving salts in a monomer solution, vacuum flash evaporating the solution, condensing the flash evaporated solution as a liquid film, and forming the condensed liquid film into a polymer composite layer on a substrate is disclosed.

  12. Spacesuit Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Hodgson, Ed; Izenson, Mike; Chan, Weibo; Bue, Grant C.

    2012-01-01

    For decades advanced spacesuit developers have pursued a regenerable, robust nonventing system for heat rejection. Toward this end, this paper investigates linking together two previously developed technologies, namely NASA s Spacesuit Water Membrane Evaporator (SWME), and Creare s Lithium Chloride Absorber Radiator (LCAR). Heat from a liquid cooled garment is transported to SWME that provides cooling through evaporation. This water vapor is then captured by solid LiCl in the LCAR with a high enthalpy of absorption, resulting in sufficient temperature lift to reject heat to space by radiation. After the sortie, the LCAR would be heated up and dried in a regenerator to drive off and recover the absorbed evaporant. A engineering development prototype was built and tested in vacuum conditions at a sink temperature of 250 K. The LCAR was able to stably reject 75 W over a 7-hour period. A conceptual design of a full-scale radiator is proposed. Excess heat rejection above 240 W would be accomplished through venting of the evaporant. Loop closure rates were predicted for various exploration environment scenarios.

  13. Evaporation and Combustion Characteristics of Multicomponent Fuels

    NASA Astrophysics Data System (ADS)

    Govindaraju, Pavan; Stagni, Alessandro; Ihme, Matthias

    2015-11-01

    Current generation fuels are mixtures of hundreds of complicated organic compounds and accurate modeling of their combustion characteristics provides fundamental physical insights which also help in the design of efficient combustors. This however requires accurate simulation of both evaporation and combustion processes, which, in case of such fuels, demands an approach based on calculating properties using only the information of functional groups present in the mixture. The presentation will elaborate on the assumptions and the framework utilized for evaporation and chemical mechanisms. We also present a comparison between various fuels used in the aviation industry as test cases while highlighting on their pros and cons. The focus of the talk will however be on the physical aspects captured using 1D simulations, i.e., preferential evaporation of each species, ignition parameters and emissions while justifying the numerical calculations with experimental data at each stage. Further work involving the coupling of flow with evaporation and combustion can be performed and we briefly discuss why a DNS is necessary to characterize the various combustion regimes. Federal Aviation Administration.

  14. Experimental Investigation of Microstructured Evaporators

    NASA Astrophysics Data System (ADS)

    Wibel, W.; Westermann, S.; Maikowske, S.; Brandner, J. J.

    2012-11-01

    Microfluidic devices have become more and more popular over the last decades [1]. Cooling is a topic where microstructures offer significant advantages compared to conventional techniques due the much higher possible surface to volume ratios and short heat transfer lengths. By evaporating of a fluid in microchannels, compact, fast and powerful cooling devices become possible [2]. Experimental results for different designs of microstructured evaporators are presented here. They have been obtained either using water as evaporating coolant or the refrigerant R134a (Tetrafluoroethane). A new microstructured evaporator design consisting of bended microchannels instead of straight channels for a better performance is shown and compared to previous results [2] for the evaporation of R134a in straight microchannels.

  15. Molecular Mechanism of Water Evaporation

    NASA Astrophysics Data System (ADS)

    Nagata, Yuki; Usui, Kota; Bonn, Mischa

    2015-12-01

    Evaporation is the process by which water changes from a liquid to a gas or vapor, and is a key step in Earth's water cycle. At the molecular level, evaporation requires breaking at least one very strong intermolecular bond between two water molecules at the interface. Despite the importance of this process the molecular mechanism by which an evaporating water molecule gains sufficient energy to escape from the surface has remained elusive. Here, we show, using molecular dynamics simulations at the water-air interface with polarizable classical force field models, that the high kinetic energy of the evaporated water molecule is enabled by a well-timed making and breaking of hydrogen bonds involving at least three water molecules at the interface, the recoil of which allows one of the molecules to escape. The evaporation of water is thus enabled by concerted, ultrafast hydrogen-bond dynamics of interfacial water, and follows one specific molecular pathway.

  16. Evaporation in the Atacama Desert: An empirical study of spatio-temporal variations and their causes

    NASA Astrophysics Data System (ADS)

    Houston, John

    2006-11-01

    SummaryThe Atacama Desert is hyper-arid, and areas where adequate moisture exists for evaporation are spatially highly restricted. Nevertheless, water resources exist and their evaluation requires knowledge of this elusive but important component of the hydrological cycle. Evaporation may occur in four typical areas: rivers and associated riparian zones, localized springs, large playas and extensive areas of bare soil after infrequent precipitation events. Transpiration is locally possible where moisture is sufficiently close to the surface to allow phreatophytes or scarce grass cover to grow, but virtually no information is available for quantification. Pan evaporation data from 11 stations for the period 1977-1991 is analyzed and complemented by analysis of an evaporation study conducted in the Salar de Atacama during 1987/1988. The results show that pan evaporation, and hence maximum potential evaporation may be considered largely a function of maximum temperature and elevation as well as density of the evaporating fluid. Actual evaporation is limited by available moisture and diminishes rapidly as the level of soil moisture saturation drops below the soil surface, extinguishing at ca. 2 m depth. Evaporation is greatest during the summer, but at higher elevations convective cloudiness develops during January and February reducing evaporating rates at a time when significant precipitation may occur. Inter-annual variations in pan evaporation are considerable and weakly correlated with ENSO, but variations in actual evaporation are damped by comparison. Regression equations are developed which have widespread applicability and may be used to estimate evaporation in areas where no site-specific data exists.

  17. Modeling Coupled Evaporation and Seepage in Ventilated Cavities

    SciTech Connect

    T. Ghezzehei; R. Trautz; S. Finsterle; P. Cook; C. Ahlers

    2004-07-01

    Cavities excavated in unsaturated geological formations are important to activities such as nuclear waste disposal and mining. Such cavities provide a unique setting for simultaneous occurrence of seepage and evaporation. Previously, inverse numerical modeling of field liquid-release tests and associated seepage into cavities were used to provide seepage-related large-scale formation properties by ignoring the impact of evaporation. The applicability of such models was limited to the narrow range of ventilation conditions under which the models were calibrated. The objective of this study was to alleviate this limitation by incorporating evaporation into the seepage models. We modeled evaporation as an isothermal vapor diffusion process. The semi-physical model accounts for the relative humidity, temperature, and ventilation conditions of the cavities. The evaporation boundary layer thickness (BLT) over which diffusion occurs was estimated by calibration against free-water evaporation data collected inside the experimental cavities. The estimated values of BLT were 5 to 7 mm for the open underground drifts and 20 mm for niches closed off by bulkheads. Compared to previous models that neglected the effect of evaporation, this new approach showed significant improvement in capturing seepage fluctuations into open cavities of low relative humidity. At high relative-humidity values (greater than 85%), the effect of evaporation on seepage was very small.

  18. Droplet evaporation on heated hydrophobic and superhydrophobic surfaces.

    PubMed

    Dash, Susmita; Garimella, Suresh V

    2014-04-01

    The evaporation characteristics of sessile water droplets on smooth hydrophobic and structured superhydrophobic heated surfaces are experimentally investigated. Droplets placed on the hierarchical superhydrophobic surface subtend a very high contact angle (∼160°) and demonstrate low roll-off angle (∼1°), while the hydrophobic substrate supports corresponding values of 120° and ∼10°. The substrates are heated to different constant temperatures in the range of 40-60 °C, which causes the droplet to evaporate much faster than in the case of natural evaporation without heating. The geometric parameters of the droplet, such as contact angle, contact radius, and volume evolution over time, are experimentally tracked. The droplets are observed to evaporate primarily in a constant-contact-angle mode where the contact line slides along the surface. The measurements are compared with predictions from a model based on diffusion of vapor into the ambient that assumes isothermal conditions. This vapor-diffusion-only model captures the qualitative evaporation characteristics on both test substrates, but reasonable quantitative agreement is achieved only for the hydrophobic surface. The superhydrophobic surface demonstrates significant deviation between the measured evaporation rate and that obtained using the vapor-diffusion-only model, with the difference being amplified as the substrate temperature is increased. A simple model considering thermal diffusion through the droplet is used to highlight the important role of evaporative cooling at the droplet interface in determining the droplet evaporation characteristics on superhydrophobic surfaces. PMID:24827255

  19. A phylogenetic approach to total evaporative water loss in mammals.

    PubMed

    Van Sant, Matthew J; Oufiero, Christopher E; Muñoz-Garcia, Agustí; Hammond, Kimberly A; Williams, Joseph B

    2012-01-01

    Maintaining appropriate water balance is a constant challenge for terrestrial mammals, and this problem can be exacerbated in desiccating environments. It has been proposed that natural selection has provided desert-dwelling mammals physiological mechanisms to reduce rates of total evaporative water loss. In this study, we evaluated the relationship between total evaporative water loss and body mass in mammals by using a recent phylogenetic hypothesis. We compared total evaporative water loss in 80 species of arid-zone mammals to that in 56 species that inhabit mesic regions, ranging in size from 4 g to 3,500 kg, to test the hypothesis that mammals from arid environments have lower rates of total evaporative water loss than mammals from mesic environments once phylogeny is taken into account. We found that arid species had lower rates of total evaporative water loss than mesic species when using a dichotomous variable to describe habitat (arid or mesic). We also found that total evaporative water loss was negatively correlated with the average maximum and minimum environmental temperature as well as the maximum vapor pressure deficit of the environment. Annual precipitation and the variable Q (a measure of habitat aridity) were positively correlated with total evaporative water loss. These results support the hypothesis that desert-dwelling mammals have lower rates of total evaporative water loss than mesic species after controlling for body mass and evolutionary relatedness regardless of whether categorical or continuous variables are used to describe habitat. PMID:22902381

  20. DNS of moderate-temperature gaseous mixing layers laden with multicomponent-fuel drops

    NASA Technical Reports Server (NTRS)

    Clercq, P. C. Le; Bellan, J.

    2004-01-01

    A formulation representing multicomponent-fuel (MC-fuel) composition as a Probability Distribution Function (PDF) depending on the molar weight is used to construct a model of a large number of MC-fuel drops evaporating in a gas flow, so as to assess the extent of fuel specificity on the vapor composition.