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Sample records for injection stretch blow

  1. Experimental Investigation of Process Conditions in Injection Stretch Blow Moulding

    NASA Astrophysics Data System (ADS)

    Salomeia, Y.; Menary, G.; Armstrong, C. G.

    2007-04-01

    Various processing parameters influence the final product properties in the stretch blow moulding process. These properties are highly dependent on the balance between the stretching of the polymer and blowing times as well as the level of the pressure inside the bottle. A data acquisition system capable of accurately measuring the process conditions within an industrial environment is discussed. Experimental work has been conducted on an industrial stretch blow moulding machine by means of replacing the original stretch rod with one that contains a force cell and a pressure transducer. Correlation between the stretching force, displacement of the rod and the pressure inside the bottle give a better understanding of the process and should allow a more precise final element simulation of the process to be developed.

  2. Effect of Biaxial Stretching at Temperatures and Strain Histories Comparable to Injection Stretch Blow Moulding on Tensile Modulus for Polyethylene Terephthalate (PET)

    NASA Astrophysics Data System (ADS)

    Tan, C. W.; Menary, G. H.; Harkin-Jones, E. M. A.; Armstrong, C. G.; Martin, P. J.

    2007-04-01

    This study is particularly relevant to the injection stretch blow moulding (ISBM) process where PET material is typically biaxially stretched to form bottles for the water and carbonated soft drinks industry. The aim of this paper is to investigate the effect of biaxial stretching on the mechanical properties of Polyethylene Terephthalate (PET) using a custom built biaxial testing machine. An initially amorphous PET sample was prepared via injection moulding to form a square sample (76mm × 76mm) suitable for stretching on the machine. This sample was then subjected to a series of biaxial tests (simultaneous and sequential) within a temperature range between 85°C and 110 °C, strain rates in the range of 1s-1 to 32s-1 and stretch ratios in the range of 1.5 to 3. Specimens were subsequently cut from the biaxial stretched sheets and used to measure the tensile modulus. Results showed that there is almost no effect found for strain rate and temperature on modulus development whilst stretch ratio and mode of deformation played the most important role on modulus development on PET under biaxial deformation.

  3. Microstructural evolution of PET under stretching and during stretch blow moulding

    NASA Astrophysics Data System (ADS)

    Picard, Martine; Billon, Noëlle

    2007-04-01

    Strain induced crystallisation of PET designed for stretch blow molding is studied combining well-controlled tensile tests and free blowing on a stretch blow prototype. Microstructure evolution is followed by WAXS and SAXS. Observations on blown parts clearly show that the microstructure can differ along the bottle and from processing conditions to another. Difference can be observed on crystalline orientation, periodic arrangement at the level of lamellae and long period. Range of long period, 8.5 to 13 nm is in agreement with literature. In certain case lamellar organisation disappears. Despite of high level of strain and evidence for strain hardening to occur during blowing no perfect crystalline pattern is observed, except in very thick zones. Interrupted tensile tests followed by quenching demonstrates that strain hardening is not correlated to prefect crystallisation. Microstructure clearly depends on the three parameters: temperature, strain rate and strain. It is concluded that strain hardening is mainly controlled by first stages of crystallisation and that actual crystallisation occurs during a following relaxation step. This later is then highly dependent upon cooling step.

  4. Thermo-mechanical simulation of liquid-supported stretch blow molding

    NASA Astrophysics Data System (ADS)

    Zimmer, J.; Stommel, M.

    2015-05-01

    Stretch blow molding is the well-established plastics forming method to produce Polyehtylene therephtalate (PET) bottles. An injection molded preform is heated up above the PET glass transition temperature (Tg˜85°C) and subsequently inflated by pressurized air into a closed cavity. In the follow-up filling process, the resulting bottle is filled with the final product. A recently developed modification of the process combines the blowing and filling stages by directly using the final liquid product to inflate the preform. In a previously published paper, a mechanical simulation and successful evaluation of this liquid-driven stretch blow molding process was presented. In this way, a realistic process parameter dependent simulation of the preform deformation throughout the forming process was enabled, whereas the preform temperature evolution during forming was neglected. However, the formability of the preform is highly reduced when the temperature sinks below Tg during forming. Experimental investigations show temperature-induced failure cases due to the fast heat transfer between hot preform and cold liquid. Therefore, in this paper, a process dependent simulation of the temperature evolution during processing to avoid preform failure is presented. For this purpose, the previously developed mechanical model is used to extract the time dependent thickness evolution. This information serves as input for the heat transfer simulation. The required material parameters are calibrated from preform cooling experiments recorded with an infrared-camera. Furthermore, the high deformation ratios during processing lead to strain induced crystallization. This exothermal reaction is included into the simulation by extracting data from preform measurements at different stages of deformation via Differential Scanning Calorimetry (DSC). Finally, the thermal simulation model is evaluated by free forming experiments, recorded by a high-speed infrared camera.

  5. Thermo-mechanical simulation of liquid-supported stretch blow molding

    SciTech Connect

    Zimmer, J.; Stommel, M.

    2015-05-22

    Stretch blow molding is the well-established plastics forming method to produce Polyehtylene therephtalate (PET) bottles. An injection molded preform is heated up above the PET glass transition temperature (Tg∼85°C) and subsequently inflated by pressurized air into a closed cavity. In the follow-up filling process, the resulting bottle is filled with the final product. A recently developed modification of the process combines the blowing and filling stages by directly using the final liquid product to inflate the preform. In a previously published paper, a mechanical simulation and successful evaluation of this liquid-driven stretch blow molding process was presented. In this way, a realistic process parameter dependent simulation of the preform deformation throughout the forming process was enabled, whereas the preform temperature evolution during forming was neglected. However, the formability of the preform is highly reduced when the temperature sinks below Tg during forming. Experimental investigations show temperature-induced failure cases due to the fast heat transfer between hot preform and cold liquid. Therefore, in this paper, a process dependent simulation of the temperature evolution during processing to avoid preform failure is presented. For this purpose, the previously developed mechanical model is used to extract the time dependent thickness evolution. This information serves as input for the heat transfer simulation. The required material parameters are calibrated from preform cooling experiments recorded with an infrared-camera. Furthermore, the high deformation ratios during processing lead to strain induced crystallization. This exothermal reaction is included into the simulation by extracting data from preform measurements at different stages of deformation via Differential Scanning Calorimetry (DSC). Finally, the thermal simulation model is evaluated by free forming experiments, recorded by a high-speed infrared camera.

  6. FE-Analysis of Stretch-Blow Moulded Bottles Using an Integrative Process Simulation

    NASA Astrophysics Data System (ADS)

    Hopmann, C.; Michaeli, W.; Rasche, S.

    2011-05-01

    The two-stage stretch-blow moulding process has been established for the large scale production of high quality PET containers with excellent mechanical and optical properties. The total production costs of a bottle are significantly caused by the material costs. Due to this dominant share of the bottle material, the PET industry is interested in reducing the total production costs by an optimised material efficiency. However, a reduced material inventory means decreasing wall thicknesses and therewith a reduction of the bottle properties (e.g. mechanical properties, barrier properties). Therefore, there is often a trade-off between a minimal bottle weight and adequate properties of the bottle. In order to achieve the objectives Computer Aided Engineering (CAE) techniques can assist the designer of new stretch-blow moulded containers. Hence, tools such as the process simulation and the structural analysis have become important in the blow moulding sector. The Institute of Plastics Processing (IKV) at RWTH Aachen University, Germany, has developed an integrative three-dimensional process simulation which models the complete path of a preform through a stretch-blow moulding machine. At first, the reheating of the preform is calculated by a thermal simulation. Afterwards, the inflation of the preform to a bottle is calculated by finite element analysis (FEA). The results of this step are e.g. the local wall thickness distribution and the local biaxial stretch ratios. Not only the material distribution but also the material properties that result from the deformation history of the polymer have significant influence on the bottle properties. Therefore, a correlation between the material properties and stretch ratios is considered in an integrative simulation approach developed at IKV. The results of the process simulation (wall thickness, stretch ratios) are transferred to a further simulation program and mapped on the bottles FE mesh. This approach allows a local

  7. Injection blow moulding single stage process: Validation of the numerical simulation through tomography analysis

    NASA Astrophysics Data System (ADS)

    Biglione, Jordan; Béreaux, Yves; Charmeau, Jean-Yves

    2016-10-01

    The injection blow moulding single stage process has been made available on standard injection moulding machine. Both the injection moulding stage and the blow moulding stage are being taken care of in an injection mould. Thus the dimensions of this mould are those of a conventional injection moulding mould. The fact that the two stages are located in the same mould leads to a process more constrained than the conventional one. This process introduces temperature gradients, molecular orientation, high stretch rates and high cooling rates. These constraints lead to a small processing window. In practice, the preform has to remain sufficiently melted to be blown so that the process takes place between the melting temperature and the crystallization temperature. In our numerical approach, the polymer is supposed to be blown in its molten state. Hence we have identified the mechanical behaviour of the polymer in its molten state through dynamical rheology experiments. A viscous Cross model has been proved to be relevant to the problem. Thermal dependence is assumed by an Arrhenius law. The process is simulated through a finite element code (POLYFLOW software) in the Ansys Workbench framework. Thickness measurements using image analysis of tomography data are performed and comparisons with the simulation results show good agreements.

  8. Simulative design and process optimization of the two-stage stretch-blow molding process

    SciTech Connect

    Hopmann, Ch.; Rasche, S.; Windeck, C.

    2015-05-22

    The total production costs of PET bottles are significantly affected by the costs of raw material. Approximately 70 % of the total costs are spent for the raw material. Therefore, stretch-blow molding industry intends to reduce the total production costs by an optimized material efficiency. However, there is often a trade-off between an optimized material efficiency and required product properties. Due to a multitude of complex boundary conditions, the design process of new stretch-blow molded products is still a challenging task and is often based on empirical knowledge. Application of current CAE-tools supports the design process by reducing development time and costs. This paper describes an approach to determine optimized preform geometry and corresponding process parameters iteratively. The wall thickness distribution and the local stretch ratios of the blown bottle are calculated in a three-dimensional process simulation. Thereby, the wall thickness distribution is correlated with an objective function and preform geometry as well as process parameters are varied by an optimization algorithm. Taking into account the correlation between material usage, process history and resulting product properties, integrative coupled simulation steps, e.g. structural analyses or barrier simulations, are performed. The approach is applied on a 0.5 liter PET bottle of Krones AG, Neutraubling, Germany. The investigations point out that the design process can be supported by applying this simulative optimization approach. In an optimization study the total bottle weight is reduced from 18.5 g to 15.5 g. The validation of the computed results is in progress.

  9. Simulative design and process optimization of the two-stage stretch-blow molding process

    NASA Astrophysics Data System (ADS)

    Hopmann, Ch.; Rasche, S.; Windeck, C.

    2015-05-01

    The total production costs of PET bottles are significantly affected by the costs of raw material. Approximately 70 % of the total costs are spent for the raw material. Therefore, stretch-blow molding industry intends to reduce the total production costs by an optimized material efficiency. However, there is often a trade-off between an optimized material efficiency and required product properties. Due to a multitude of complex boundary conditions, the design process of new stretch-blow molded products is still a challenging task and is often based on empirical knowledge. Application of current CAE-tools supports the design process by reducing development time and costs. This paper describes an approach to determine optimized preform geometry and corresponding process parameters iteratively. The wall thickness distribution and the local stretch ratios of the blown bottle are calculated in a three-dimensional process simulation. Thereby, the wall thickness distribution is correlated with an objective function and preform geometry as well as process parameters are varied by an optimization algorithm. Taking into account the correlation between material usage, process history and resulting product properties, integrative coupled simulation steps, e.g. structural analyses or barrier simulations, are performed. The approach is applied on a 0.5 liter PET bottle of Krones AG, Neutraubling, Germany. The investigations point out that the design process can be supported by applying this simulative optimization approach. In an optimization study the total bottle weight is reduced from 18.5 g to 15.5 g. The validation of the computed results is in progress.

  10. Measurement Of Thermal Contact Resistance Between The Mold And The Polymer For The Stretch-blow Molding Process

    NASA Astrophysics Data System (ADS)

    Bordival, M.; Schmidt, F. M.; Le Maoult, Y.; Coment, E.

    2007-04-01

    In the stretch-blow molding process, the heat transfer between the polymer and the mold is of prime interest. Although the time of contact is very short (typically around 0.5 s), the heat transfer affects the mechanical properties of the bottle, and the quality of final parts. In order to model heat transfers at the interface, a classical approach — generally adopted in numerical softwares — is to impose the heat flux density boundary condition thanks to a parameter called Thermal Contact Resistance (TCR). This paper focuses on describing the experimental method developed in order to measure evolution of this thermal parameter (TCR) versus time, as well as results obtained on the CROMeP blowing machine. In this study, a mold has been instrumented with two different sensors. The first probe allows to estimate the heat flux density and temperature at the mold surface temperature, using a linear inverse heat condution problem (Function Specification Method). The second device is used to measure the surface temperature of the PET during the blowing. This measurement is non intrusive, and can be applied within an industrial environment during the blowing step. In addition, air pressure inside the preform is also measured during the blowing. This work is part of the European project "APT_PACK" (Advanced knowledge of Polymer deformation for Tomorrow's PACKaging).

  11. Foam injection molding of thermoplastic elastomers: Blowing agents, foaming process and characterization of structural foams

    NASA Astrophysics Data System (ADS)

    Ries, S.; Spoerrer, A.; Altstaedt, V.

    2014-05-01

    Polymer foams play an important role caused by the steadily increasing demand to light weight design. In case of soft polymers, like thermoplastic elastomers (TPE), the haptic feeling of the surface is affected by the inner foam structure. Foam injection molding of TPEs leads to so called structural foam, consisting of two compact skin layers and a cellular core. The properties of soft structural foams like soft-touch, elastic and plastic behavior are affected by the resulting foam structure, e.g. thickness of the compact skins and the foam core or density. This inner structure can considerably be influenced by different processing parameters and the chosen blowing agent. This paper is focused on the selection and characterization of suitable blowing agents for foam injection molding of a TPE-blend. The aim was a high density reduction and a decent inner structure. Therefore DSC and TGA measurements were performed on different blowing agents to find out which one is appropriate for the used TPE. Moreover a new analyzing method for the description of processing characteristics by temperature dependent expansion measurements was developed. After choosing suitable blowing agents structural foams were molded with different types of blowing agents and combinations and with the breathing mold technology in order to get lower densities. The foam structure was analyzed to show the influence of the different blowing agents and combinations. Finally compression tests were performed to estimate the influence of the used blowing agent and the density reduction on the compression modulus.

  12. Stretching

    MedlinePlus

    ... benefits of stretching before working out. Traditional, or "static," stretching may lead to decreased muscle strength and performance. Consider doing dynamic stretches before and static stretching after a workout. Stretching still can be ...

  13. Stretching

    MedlinePlus

    ... activity, dynamic stretching allows for full range of motion of the joints. continue Stretching Stretching used to ... addition, stretching provides increased: flexibility joint range and motion blood flow to muscles Stretching has to be ...

  14. The Use of Elasto-Visco-Plastic Material Model Coupled with Pressure-Volume Thermodynamic Relationship to Simulate the Stretch Blow Molding of Polyethylene Terephthalate

    NASA Astrophysics Data System (ADS)

    Mir, H.; Benrabah, Z.; Thibault, F.

    2007-05-01

    The use of polyethylene terephthalate (PET) in the stretch blow molding process presents several challenging issues due to various processing parameters and complex behavior of the material, which is both temperature and strain-rate dependent. In this paper, we generalize the G'Sell-Jonas law in 3D to model and simulate the elasto-visco-plastic (EVP) behavior of PET, taking into account strain-hardening and strain-softening. It is observed that the internal pressure (inside the preform) is significantly different from the nominal pressure (imposed in the blowing device upstream) since the internal pressure and the enclosed volume of the preform are fully coupled. In order to accurately simulate this phenomenon, a thermodynamic model was used to characterize the pressure-volume relationship (PVR). The predicted pressure evolution is thus more realistic when imposing only the machine power of the blowing device (air compressor or vacuum pump). Mechanical and temperature equilibrium equations are fully nonlinear and solved separately with implicit schemes on the current deformed configuration, which is updated at each time step. Biaxial characterization tests were used to determine the model parameters in order to simulate the stretch blow molding process using the pressure-volume thermodynamic relationship. To validate this model, thickness predictions for three industrial cases will be presented and compared to experimental measurements.

  15. Laser Blow-Off Impurity Injection Experiments at the HSX Stellarator

    NASA Astrophysics Data System (ADS)

    Clark, C.; Anderson, D. T.; Anderson, F. S. B.; Likin, K. M.; Talmadge, J. N.; Zhai, K.; Lore, J.

    2011-10-01

    Experiments are under way to measure impurity transport in a quasisymmetric stellarator for the first time. A laser blow-off impurity injection system, which is capable of rapidly depositing a small, controlled quantity of a wide variety of solid impurities into the confinement volume, has been installed and successfully tested. AXUV photodiode arrays equipped with optional soft x-ray filters have also been installed on the machine. The arrays will take time-resolved measurements of the impurity radiation, which will be inverted into radial profile and then interpreted using the transport code, STRAHL and atomic data from ADAS to determine the transport coefficients within the paradigm of a diffusivity and convective velocity. Details of the system and first results will be presented along with PENTA calculations of the neoclassical predicted impurity transport Work supported by US DOE contracts DE-FG02-01ER54615 and DE-FG02-93ER54222.

  16. Injection of new psychoactive substance snow blow associated with recently acquired HIV infections among homeless people who inject drugs in Dublin, Ireland, 2015.

    PubMed

    Giese, Coralie; Igoe, Derval; Gibbons, Zorina; Hurley, Caroline; Stokes, Siobhan; McNamara, Sinead; Ennis, Orla; O'Donnell, Kate; Keenan, Eamon; De Gascun, Cillian; Lyons, Fiona; Ward, Mary; Danis, Kostas; Glynn, Ronan; Waters, Allison; Fitzgerald, Margaret

    2015-01-01

    In February 2015, an outbreak of recently acquired HIV infections among people who inject drugs (PWID) was identified in Dublin, following similar outbreaks in Greece and Romania in 2011. We compared drug and risk behaviours among 15 HIV cases and 39 controls. Injecting a synthetic cathinone, snow blow, was associated with recent HIV infection (AOR: 49; p=0.003). Prevention and control efforts are underway among PWID in Dublin, but may also be needed elsewhere in Europe.

  17. Blowing DNA bubbles.

    PubMed

    Severin, N; Zhuang, W; Ecker, C; Kalachev, A A; Sokolov, I M; Rabe, J P

    2006-11-01

    We report here experimental observations which indicate that topologically or covalently formed polymer loops embedded in an ultrathin liquid film on a solid substrate can be "blown" into circular "bubbles" during scanning force microscopy (SFM) imaging. In particular, supercoiled vector DNA has been unraveled, moved, stretched, and overstretched to two times its B-form length and then torn apart. We attribute the blowing of the DNA bubbles to the interaction of the tapping SFM tip with the ultrathin liquid film.

  18. Numerical Solution for the Effect of Suction or Injection on Flow of Nanofluids Past a Stretching Sheet

    NASA Astrophysics Data System (ADS)

    Abd Elazem, Nader Y.

    2016-06-01

    The flow of nanofluids past a stretching sheet has attracted much attention owing to its wide applications in industry and engineering. Numerical solution has been discussed in this article for studying the effect of suction (or injection) on flow of nanofluids past a stretching sheet. The numerical results carried out using Chebyshev collocation method (ChCM). Useful results for temperature profile, concentration profile, reduced Nusselt number, and reduced Sherwood number are discussed in tabular and graphical forms. It was also demonstrated that both temperature and concentration profiles decrease by an increase from injection to suction. Moreover, the numerical results show that the temperature profiles decrease at high values of Prandtl number Pr. Finally, the present results showed that the reduced Nusselt number is a decreasing function, whereas the reduced Sherwood number is an increasing function at fixed values of Prandtl number Pr, Lewis number Le and suction (or injection) parameter s for variation of Brownian motion parameter Nb, and thermophoresis parameter Nt.

  19. Botulinum Neurotoxin A injections influence stretching of the gastrocnemius muscle-tendon unit in an animal model.

    PubMed

    Haubruck, Patrick; Mannava, Sandeep; Plate, Johannes F; Callahan, Michael F; Wiggins, Walter F; Schmidmaier, Gerhard; Tuohy, Christopher J; Saul, Katherine R; Smith, Thomas L

    2012-08-01

    Botulinum Neurotoxin A (BoNT-A) injections have been used for the treatment of muscle contractures and spasticity. This study assessed the influence of (BoNT-A) injections on passive biomechanical properties of the muscle-tendon unit. Mousegastrocnemius muscle (GC) was injected with BoNT-A (n = 18) or normal saline (n = 18) and passive, non-destructive, in vivo load relaxation experimentation was performed to examine how the muscle-tendon unit behaves after chemical denervation with BoNT-A. Injection of BoNT-A impaired passive muscle recovery (15% vs. 35% recovery to pre-stretching baseline, p < 0.05) and decreased GC stiffness (0.531 ± 0.061 N/mm vs. 0.780 ± 0.037 N/mm, p < 0.05) compared to saline controls. The successful use of BoNT-A injections as an adjunct to physical therapy may be in part attributed to the disruption of the stretch reflex; thereby modulating in vivo passive muscle properties. However, it is also possible that BoNT-A injection may alter the structure of skeletal muscle; thus modulating the in vivo passive biomechanical properties of the muscle-tendon unit.

  20. Comparison between Steroid Injection and Stretching Exercise on the Scalene of Patients with Upper Extremity Paresthesia: Randomized Cross-Over Study

    PubMed Central

    Kim, Yong Wook; Yoon, Seo Yeon; Park, Yongbum; Chang, Won Hyuk

    2016-01-01

    Purpose To compare the therapeutic effects on upper extremity paresthesia of intra-muscular steroid injections into the scalene muscle with those of stretching exercise only. Materials and Methods Twenty patients with upper extremity paresthesia who met the criteria were recruited to participate in this single-blind, crossover study. Fourteen of 20 patients were female. The average age was 45.0±10.5 years and duration of symptom was 12.2±8.7 months. Each participant completed one injection and daily exercise program for 2 weeks. After randomization, half of all patients received ultrasound-guided injection of scalene muscles before exercise, while the other was invested for the other patients. Results After two weeks, there was a significant decrease of the visual analog scale score of treatment effect compared with baseline in both groups (6.90 to 2.85 after injection and 5.65 to 4.05 after stretching exercise, p<0.01). However, injection resulted in greater improvements than stretching exercise (p<0.01). The number of patients with successful treatment, defined as >50% reduction in post-treatment visual analog scale, was 18 of 20 (90.0%) after injection, compared to 5 of 20 (25.0%) after stretching exercise. There were no cases of unintended brachial plexus block after injection. Conclusion Ultrasound-guided steroid injection or stretching exercise of scalene muscles led to reduced upper extremity paresthesia in patients who present with localized tenderness in the scalene muscle without electrodiagnostic test abnormalities, although injection treatment resulted in more improvements. The results suggest that symptoms relief might result from injection into the muscle alone not related to blockade of the brachial plexus. PMID:26847305

  1. Blowing Polymer Bubbles in an Acoustic Levitator

    NASA Technical Reports Server (NTRS)

    Lee, M. C.

    1985-01-01

    In new manufacturing process, small gas-filled polymer shells made by injecting gas directly into acoustically levitated prepolymer drops. New process allows sufficient time for precise control of shell geometry. Applications foreseen in fabrication of deuterium/tritium-filled fusion targets and in pharmaceutical coatings. New process also useful in glass blowing and blow molding.

  2. Investigations on the processing of solid silicon rubber in blow moulding

    NASA Astrophysics Data System (ADS)

    Hopmann, Ch.; Funk, A.; Windeck, C.

    2015-05-01

    Complex hollow parts made of thermoplastics are often produced in the extrusion blow moulding process. This cost-efficient production technique with a high reproducibility, a high degree of automation and short cycle times has not been adapted for rubber processing until now. Current research activities at IKV focus on the processing of silicone rubber in extrusion blow moulding with an adapted processing and rapid cross-linking systems. The blow moulding process allows an automated and effective production of complex hollow parts made of solid silicone rubber in one step. The use of expensive core techniques, which lead to comparatively high reject rates in injection moulding, is not necessary. Expensive and time-consuming assembly steps can be reduced. This substantially increases the efficiency of the process. A systematic material selection of different solid silicone rubber compounds and cross-linking systems for the extrusion blow moulding process is a major focus of investigation. In this context, the term blow mouldability of polymers is defined and the suitability of solid silicone rubbers in combination with cross-linking systems for the blow moulding process is analysed. Characteristic mechanical and physical properties allow the identification of suitable material systems and give advice for the implementation of the new process. Extrusion blow moulding of solid silicone rubber is a new and innovative manufacturing concept to produce elastomeric hollow parts. Influences on the forming process are not known for silicone rubber yet. Therefore, to obtain a detailed process description is another focus of the research project. This includes the forming process, the processing and the influences of the material and the curing reaction on the processing. In the first instance, the investigation and description of the forming process as well as the detailed analysis of the processing parameters, such as curing time, mould temperature, wall thickness of the

  3. Blowing in the Wind Animations

    NASA Technical Reports Server (NTRS)

    2008-01-01

    These are two separate, side-by-side animations made from the same nine images the Surface Stereo Imager (SSI) on NASA's Phoenix Mars Lander took looking into the sky after 5:17 p.m. local time on Sol 8 (June 2, 2008), the eighth Martian day of the mission. The SSI was pointed almost straight up, toward the southwest. Zenith is near the top of the center frame.

    In the left animation, the images were stretched to enhance contrast. The right animation highlights variations between each image and the next. The variations are likely dust blown by winds passing through the SSI's field of view. The images suggest the dust is blowing from west to east.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  4. Blowing up the Earth

    NASA Astrophysics Data System (ADS)

    Benge, Raymond

    2006-10-01

    An occasional theme in science fiction involves blowing up a planet. In ``Star Wars,'' the Death Star blows up Alderan. In ``The Hitchhiker's Guide to the Galaxy,'' a Vorgon destructor fleet blows up Earth to make room for a cosmic bypass. So, as an exercise for upper division students, or the more advance first year calculus based physics students, the energy needed to disassemble Earth can be computed. Assuming that advanced scifi aliens get their energy from matter-antimatter interactions, students can then compute the amount of antimatter needed to accomplish the task.

  5. Stretch Marks

    MedlinePlus

    ... like during puberty), that person may get fine lines on the body called stretch marks. Stretch marks happen when the skin is pulled by rapid growth or stretching. Although the skin is usually fairly elastic, when it's overstretched, the normal production of collagen (the major protein that makes up ...

  6. Five Blows to Mankind's Narcissism.

    ERIC Educational Resources Information Center

    Pedrini, D. T.; Pedrini, Bonnie C.

    1978-01-01

    Freud identified three blows to mankind's narcissism--cosmological, biological, and psychological. Conjectural fourth and fifth blows might be universological (the discovery of other intelligent beings) and earthological (the demise of this planet via waste, pollution, etc.). (Author/JC)

  7. Delta wing vortex manipulation using pulsed and steady blowing during ramp pitching

    NASA Technical Reports Server (NTRS)

    Moreira, J.; Johari, H.

    1995-01-01

    The effectiveness of steady and pulsed blowing as a method of controlling delta wing vortices during ramp pitching has been investigated in flow visualization experiments conducted in a water tunnel. The recessed angled spanwise blowing technique was utilized for vortex manipulation. This technique was implemented on a beveled 60 delta wing using a pair of blowing ports located beneath the vortex core at 40% chord. The flow was injected primarily in the spanwise direction but was also composed of a component normal to the wing surface. The location of vortex burst was measured as a function of blowing intensity and pulsing frequency under static conditions, and the optimum blowing case was applied at three different wing pitching rates. Experimental results have shown that, when the burst location is upstream of the blowing port, pulsed blowing delays vortex breakdown in static and dynamic cases. Dynamic tests verified the existence of a hysteresis effect and demonstrated the improvements offered by pulsed blowing over both steady blowing and no-blowing scenarios. The application of blowing, at the optimum pulsing frequency, made the vortex breakdown location comparable in static and ramp pitch-up conditions.

  8. Evaluation of variational principle based model for LDPE large scale film blowing process

    NASA Astrophysics Data System (ADS)

    Kolarik, Roman; Zatloukal, Martin

    2013-04-01

    In this work, variational principle based film blowing model combined with Pearson and Petrie formulation, considering non-isothermal processing conditions and novel generalized Newtonian model allowing to capture steady shear and uniaxial extensional viscosities has been validated by using experimentally determined bubble shape and velocity profile for LDPE sample on large scale film blowing line. It has been revealed that the minute change in the flow activation energy can significantly influence the film stretching level.

  9. Coker blow down recovery system

    SciTech Connect

    Holloway, R.L.; Miller, J.A.; Winters, J.E.

    1982-06-15

    A coker blow down recovery system for recovering additional ueful fuel components such as c1-c7 hydrocarbons from a coker vessel is disclosed. A significant reduction in sulfur components contained in coker blow down gases, e.g., fuel gases, is also achieved.

  10. Blowing Flap Experiment: PIV Measurements

    NASA Technical Reports Server (NTRS)

    Hutcheson, Florence V.; Stead, Daniel J.; Bremmer, David M.

    2004-01-01

    PIV measurements of the flow in the region of a flap side edge are presented for several flap configurations. The test model is a NACA 63(sub 2)-215 Hicks Mod-B main element airfoil with a half-span Fowler flap. Air is blown from small slots located along the flap side edge on either the top, bottom or side surfaces. The test set up is described and flow measurements for a baseline and three blowing flap configurations are presented. The effects that the flap tip jets have on the structure of the flap side edge flow are discussed for each of the flap configurations tested. The results indicate that blowing air from a slot located along the top surface of the flap greatly weakened the top vortex system and pushed it further off the top surface. Blowing from the bottom flap surface kept the strong side vortex further outboard while blowing from the side surface only strengthened the flap vortex system. It is concluded that blowing from the top or bottom surfaces of the flap may lead to a reduction of flap side edge noise.

  11. MHD flow and heat transfer of a viscous fluid over a radially stretching power-law sheet with suction/injection in a porous medium

    NASA Astrophysics Data System (ADS)

    Khan, M.; Munir, A.; Shahzad, A.; Shah, A.

    2015-03-01

    A steady boundary layer flow and heat transfer over a radially stretching isothermal porous sheet is analyzed. Stretching is assumed to follow a radial power law, and the fluid is electrically conducting in the presence of a transverse magnetic field with a very small magnetic Reynolds number. The governing nonlinear partial differential equations are reduced to a system of nonlinear ordinary differential equations by using appropriate similarity transformations, which are solved analytically by the homotopy analysis method (HAM) and numerically by employing the shooting method with the adaptive Runge-Kutta method and Broyden's method in the domain [0,∞). Analytical expressions for the velocity and temperature fields are derived. The influence of pertinent parameters on the velocity and temperature profiles is discussed in detail. The skin friction coefficient and the local Nusselt number are calculated as functions of several influential parameters. The results predicted by both methods are demonstrated to be in excellent agreement. Moreover, HAM results for a particular problem are also compared with exact solutions.

  12. Diurnal patterns of blowing sand

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The diurnal pattern of blowing sand results from a complex process that involves the interaction between the sun, wind, and earth. During the day, solar heating produces thermal instability, which enhances the convective mixing of high momentum winds from the upper levels of the atmosphere to the s...

  13. The Early Years: Blowing Bubbles

    ERIC Educational Resources Information Center

    Ashbrook, Peggy

    2016-01-01

    Blowing bubbles is not only a favorite summer activity for young children. Studying bubbles that are grouped together, or "foam," is fun for children and fascinating to many real-world scientists. Foam is widely used--from the bedroom (mattresses) to outer space (insulating panels on spacecraft). Bubble foam can provide children a…

  14. 21 CFR 868.5220 - Blow bottle.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Blow bottle. 868.5220 Section 868.5220 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5220 Blow bottle. (a) Identification. A blow bottle is a...

  15. Control of Cavity Resonance Using Oscillatory Blowing

    NASA Technical Reports Server (NTRS)

    Scarfe, Alison Lamp; Chokani, Ndaona

    2000-01-01

    The near-zero net mass oscillatory blowing control of a subsonic cavity flow has been experimentally investigated. An actuator was designed and fabricated to provide both steady and oscillatory blowing over a range of blowing amplitudes and forcing frequencies. The blowing was applied just upstream of the cavity front Wall through interchangeable plate configurations These configurations enabled the effects of hole size, hole shape, and blowing angle to be examined. A significant finding is that in terms of the blowing amplitude, the near zero net mass oscillatory blowing is much more effective than steady blowing; momentum coefficients Lip two orders of magnitude smaller than those required for steady blowing are sufficient to accomplish the same control of cavity resonance. The detailed measurements obtained in the experiment include fluctuating pressure data within the cavity wall, and hot-wire measurements of the cavity shear layer. Spectral and wavelet analysis techniques are applied to understand the dynamics and mechanisms of the cavity flow with control. The oscillatory blowing, is effective in enhancing the mixing in the cavity shear layer and thus modifying the feedback loop associated with the cavity resonance. The nonlinear interactions in the cavity flow are no longer driven by the resonant cavity modes but by the forcing associated with the oscillatory blowing. The oscillatory blowing does not suppress the mode switching behavior of the cavity flow, but the amplitude modulation is reduced.

  16. Stretching Safely and Effectively

    MedlinePlus

    ... that stretching immediately before an event weakens hamstring strength. Instead of static stretching, try performing a "dynamic ... Acute effects of static vs. ballistic stretching on strength and muscular fatigue of ballet dancers and resistance- ...

  17. Remarks on the blow-up criterion of the three-dimensional Euler equations

    NASA Astrophysics Data System (ADS)

    Chae, Dongho

    2005-05-01

    In this paper we prove that the finite time blow-up of classical solutions of the three-dimensional homogeneous incompressible Euler equations are controlled by the Besov space, \\dot{B}^0_{\\infty, 1} , norm of the two components of the vorticity. For the axisymmetric flows with swirl we deduce that the blow-up of solution is controlled by the same Besov space norm of the angular component of the vorticity. For a proof of these results we use the Beale-Kato-Majda criterion, and the special structure of the vortex stretching term in the vorticity formulation of the Euler equations.

  18. Stretching Impacts Inflammation Resolution in Connective Tissue.

    PubMed

    Berrueta, Lisbeth; Muskaj, Igla; Olenich, Sara; Butler, Taylor; Badger, Gary J; Colas, Romain A; Spite, Matthew; Serhan, Charles N; Langevin, Helene M

    2016-07-01

    Acute inflammation is accompanied from its outset by the release of specialized pro-resolving mediators (SPMs), including resolvins, that orchestrate the resolution of local inflammation. We showed earlier that, in rats with subcutaneous inflammation of the back induced by carrageenan, stretching for 10 min twice daily reduced inflammation and improved pain, 2 weeks after carrageenan injection. In this study, we hypothesized that stretching of connective tissue activates local pro-resolving mechanisms within the tissue in the acute phase of inflammation. In rats injected with carrageenan and randomized to stretch versus no stretch for 48 h, stretching reduced inflammatory lesion thickness and neutrophil count, and increased resolvin (RvD1) concentrations within lesions. Furthermore, subcutaneous resolvin injection mimicked the effect of stretching. In ex vivo experiments, stretching of connective tissue reduced the migration of neutrophils and increased tissue RvD1 concentration. These results demonstrate a direct mechanical impact of stretching on inflammation-regulation mechanisms within connective tissue.

  19. Black Hole Blows Big Bubble

    NASA Astrophysics Data System (ADS)

    2010-07-01

    Combining observations made with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. This object, also known as a microquasar, blows a huge bubble of hot gas, 1000 light-years across, twice as large and tens of times more powerful than other known microquasars. The discovery is reported this week in the journal Nature. "We have been astonished by how much energy is injected into the gas by the black hole," says lead author Manfred Pakull. "This black hole is just a few solar masses, but is a real miniature version of the most powerful quasars and radio galaxies, which contain black holes with masses of a few million times that of the Sun." Black holes are known to release a prodigious amount of energy when they swallow matter. It was thought that most of the energy came out in the form of radiation, predominantly X-rays. However, the new findings show that some black holes can release at least as much energy, and perhaps much more, in the form of collimated jets of fast moving particles. The fast jets slam into the surrounding interstellar gas, heating it and triggering an expansion. The inflating bubble contains a mixture of hot gas and ultra-fast particles at different temperatures. Observations in several energy bands (optical, radio, X-rays) help astronomers calculate the total rate at which the black hole is heating its surroundings. The astronomers could observe the spots where the jets smash into the interstellar gas located around the black hole, and reveal that the bubble of hot gas is inflating at a speed of almost one million kilometres per hour. "The length of the jets in NGC 7793 is amazing, compared to the size of the black hole from which they are launched," says co-author Robert Soria [1]. "If the black hole were shrunk to the size of a soccer ball, each jet would extend from the Earth to beyond the orbit of Pluto." This research will help

  20. Black Hole Blows Big Bubble

    NASA Astrophysics Data System (ADS)

    2010-07-01

    Combining observations made with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. This object, also known as a microquasar, blows a huge bubble of hot gas, 1000 light-years across, twice as large and tens of times more powerful than other known microquasars. The discovery is reported this week in the journal Nature. "We have been astonished by how much energy is injected into the gas by the black hole," says lead author Manfred Pakull. "This black hole is just a few solar masses, but is a real miniature version of the most powerful quasars and radio galaxies, which contain black holes with masses of a few million times that of the Sun." Black holes are known to release a prodigious amount of energy when they swallow matter. It was thought that most of the energy came out in the form of radiation, predominantly X-rays. However, the new findings show that some black holes can release at least as much energy, and perhaps much more, in the form of collimated jets of fast moving particles. The fast jets slam into the surrounding interstellar gas, heating it and triggering an expansion. The inflating bubble contains a mixture of hot gas and ultra-fast particles at different temperatures. Observations in several energy bands (optical, radio, X-rays) help astronomers calculate the total rate at which the black hole is heating its surroundings. The astronomers could observe the spots where the jets smash into the interstellar gas located around the black hole, and reveal that the bubble of hot gas is inflating at a speed of almost one million kilometres per hour. "The length of the jets in NGC 7793 is amazing, compared to the size of the black hole from which they are launched," says co-author Robert Soria [1]. "If the black hole were shrunk to the size of a soccer ball, each jet would extend from the Earth to beyond the orbit of Pluto." This research will help

  1. Flush or blow lines adequately

    SciTech Connect

    Junique, J.C.

    1988-07-01

    During the commissioning of new plants, before initial startup, an important step is to clean debris from pipes and equipment. This is usually done by flushing with water or blowing with steam or air. It is not the intention of this article to give recommendation about how to proceed, but rather to give a general method to estimate the effectiveness of this operation. The method is based on the general theory of particle dynamics and the concept of drag force - the force needed to displace particles and move them along through the system. We want to make sure the degree of cleanliness obtained at the end of flushing or blowing is such that, later, in the most critical case during operation or operational upset, the particles which are left in the pipework or equipment will not move further. Therefore, the notion of drag force is useful to make comparisons between normal operation and cleaning operation. The concept can also be used to compare the efficiency of different cleaning media; for example, whether to use air blowing or water flushing.

  2. Get up and Stretch

    ERIC Educational Resources Information Center

    Crupi, Jeffrey

    2004-01-01

    Daily stretching has many benefits for one's body. It can relieve stress and tension, it increases flexibility and it can help prevent injuries. There are many stretching exercises that a teacher can do with his or her students to help promote daily stretching routines. In this article, the author presents several stretching exercises and some…

  3. Blow molding of melt processible rubber

    SciTech Connect

    Abell, W.R.; Stuart, R.E.; Myrick, R.E.

    1991-07-01

    This article discusses the advantages of making hollow rubber parts by blow molding thermoplastic elastomers (TPEs) versus conventional rubber processing. It describes the various types of blow molding processes and it provides some insight into the rheological properties of melt processible rubber (MPR) and how MPR should be molded by each of these processes. A number of blow molded applications for MPR are also discussed.

  4. Blowing Circulation Control on a Seaplane Airfoil

    NASA Astrophysics Data System (ADS)

    Guo, B. D.; Liu, P. Q.; Qu, Q. L.

    2011-09-01

    RANS simulations are presented for blowing circulation control on a seaplane airfoil. Realizable k-epsilon turbulent model and pressure-based coupled algorithm with second-order discretization were adopted to simulate the compressible flow. Both clear and simple flap configuration were simulated with blowing momentum coefficient Cμ = 0, 0.15 and 0.30. The results show that blowing near the airfoil trailing edge could enhance the Coanda effect, delay the flow separation, and increase the lift coefficient dramatically. The blowing circulation control is promising to apply to taking off and landing of an amphibious aircraft or seaplane.

  5. An inverse blow-up problem

    NASA Astrophysics Data System (ADS)

    Kamimura, Yutaka; Usami, Hiroyuki

    2016-12-01

    This paper studies an inverse problem to determine a nonlinearity of an autonomous equation from blow-up time of solutions to the equation. Firstly we prove a global continuation result showing that a nonlinearity realizing blow-up time for large initial data can be continued in the direction of smaller data as long as the blow-up time is Lipschitz continuous. Secondly we develop a method based upon a Wiener-Hopf structure by which the existence and uniqueness of a nonlinearity realizing blow-up time for large initial data is shown. These enable us to establish a global existence and uniqueness result for the inverse problem.

  6. Heat Transfer and Flow of a Casson Fluid Due to a Stretching Cylinder with the Soret and Dufour Effects

    NASA Astrophysics Data System (ADS)

    Mahdy, A.

    2015-07-01

    Numerical solutions of the problem on flow and heat transfer of a non-Newtonian fluid outside a stretching permeable cylinder are obtained with regard to suction or blowing and the Soret and Dufour effects. The Casson fluid model is used to characterize the non-Newtonian fluid behavior. The governing partial differential equations are reduced to a system of nonlinear ordinary differential equations by employing similarity transformations, and the obtained equations are solved numerically by using the shooting technique. The main purpose of the study is to investigate the effect of the governing parameters, namely, the Casson, Soret, and Dufour parameters, the suction/injection parameter, and the Prandtl and Reynolds numbers, on the velocity and temperature profiles, as well as on the skin friction coefficient and temperature gradient at the surface.

  7. Blow Collection as a Non-Invasive Method for Measuring Cortisol in the Beluga (Delphinapterus leucas)

    PubMed Central

    Thompson, Laura A.; Spoon, Tracey R.; Goertz, Caroline E. C.; Hobbs, Roderick C.; Romano, Tracy A.

    2014-01-01

    Non-invasive sampling techniques are increasingly being used to monitor glucocorticoids, such as cortisol, as indicators of stressor load and fitness in zoo and wildlife conservation, research and medicine. For cetaceans, exhaled breath condensate (blow) provides a unique sampling matrix for such purposes. The purpose of this work was to develop an appropriate collection methodology and validate the use of a commercially available EIA for measuring cortisol in blow samples collected from belugas (Delphinapterus leucas). Nitex membrane stretched over a petri dish provided the optimal method for collecting blow. A commercially available cortisol EIA for measuring human cortisol (detection limit 35 pg ml−1) was adapted and validated for beluga cortisol using tests of parallelism, accuracy and recovery. Blow samples were collected from aquarium belugas during monthly health checks and during out of water examination, as well as from wild belugas. Two aquarium belugas showed increased blow cortisol between baseline samples and 30 minutes out of water (Baseline, 0.21 and 0.04 µg dl−1; 30 minutes, 0.95 and 0.14 µg dl−1). Six wild belugas also showed increases in blow cortisol between pre and post 1.5 hour examination (Pre 0.03, 0.23, 0.13, 0.19, 0.13, 0.04 µg dl−1, Post 0.60, 0.31, 0.36, 0.24, 0.14, 0.16 µg dl−1). Though this methodology needs further investigation, this study suggests that blow sampling is a good candidate for non-invasive monitoring of cortisol in belugas. It can be collected from both wild and aquarium animals efficiently for the purposes of health monitoring and research, and may ultimately be useful in obtaining data on wild populations, including endangered species, which are difficult to handle directly. PMID:25464121

  8. FEASTING BLACK HOLE BLOWS BUBBLES

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A monstrous black hole's rude table manners include blowing huge bubbles of hot gas into space. At least, that's the gustatory practice followed by the supermassive black hole residing in the hub of the nearby galaxy NGC 4438. Known as a peculiar galaxy because of its unusual shape, NGC 4438 is in the Virgo Cluster, 50 million light-years from Earth. These NASA Hubble Space Telescope images of the galaxy's central region clearly show one of the bubbles rising from a dark band of dust. The other bubble, emanating from below the dust band, is barely visible, appearing as dim red blobs in the close-up picture of the galaxy's hub (the colorful picture at right). The background image represents a wider view of the galaxy, with the central region defined by the white box. These extremely hot bubbles are caused by the black hole's voracious eating habits. The eating machine is engorging itself with a banquet of material swirling around it in an accretion disk (the white region below the bright bubble). Some of this material is spewed from the disk in opposite directions. Acting like high-powered garden hoses, these twin jets of matter sweep out material in their paths. The jets eventually slam into a wall of dense, slow-moving gas, which is traveling at less than 223,000 mph (360,000 kph). The collision produces the glowing material. The bubbles will continue to expand and will eventually dissipate. Compared with the life of the galaxy, this bubble-blowing phase is a short-lived event. The bubble is much brighter on one side of the galaxy's center because the jet smashed into a denser amount of gas. The brighter bubble is 800 light-years tall and 800 light-years across. The observations are being presented June 5 at the American Astronomical Society meeting in Rochester, N.Y. Both pictures were taken March 24, 1999 with the Wide Field and Planetary Camera 2. False colors were used to enhance the details of the bubbles. The red regions in the picture denote the hot gas

  9. Stretched Wire Mechanics

    SciTech Connect

    Bowden, Gordon; /SLAC

    2005-09-06

    Stretched wires are beginning to play an important role in the alignment of accelerators and synchrotron light sources. Stretched wires are proposed for the alignment of the 130 meter long LCLS undulator. Wire position technology has reached sub-micron resolution yet analyses of perturbations to wire straightness are hard to find. This paper considers possible deviations of stretched wire from the simple 2-dimensional catenary form.

  10. Augmentation of maneuver performance by spanwise blowing

    NASA Technical Reports Server (NTRS)

    Erickson, G. E.; Campbell, J. F.

    1977-01-01

    A generalized wind tunnel model was tested to investigate new component concepts utilizing spanwise blowing to provide improved maneuver characteristics for advanced fighter aircraft. Primary emphasis was placed on high angle of attack performance, stability, and control at subsonic speeds. Spanwise blowing on a 44 deg swept trapezoidal wing resulted in leading edge vortex enhancement with subsequent large vortex-induced lift increments and drag polar improvements at the higher angles of attack. Small deflections of a leading edge flap delayed these lift and drag benefits to higher angles of attack. In addition, blowing was more effective at higher Mach numbers. Spanwise blowing in conjunction with a deflected trailing edge flap resulted in lift and drag benefits that exceeded the summation of the effects of each high lift device acting alone. Asymmetric blowing was an effective lateral control device at the higher angles of attack. Spanwise blowing on the wing reduced horizontal tail loading and improved the lateral-directional stability characteristics of a wing-horizontal tail-vertical tail configuration.

  11. PIV Measurements on a Blowing Flap

    NASA Technical Reports Server (NTRS)

    Hutcheson, Florence V.; Stead, Daniel J.

    2004-01-01

    PIV measurements of the flow in the region of a flap side edge are presented for several blowing flap configurations. The test model is a NACA 63(sub 2)-215 Hicks Mod-B main-element airfoil with a half-span Fowler flap. Air is blown from small slots located along the flap side edge on either the top, bottom or side surfaces. The test set up is described and flow measurements for a baseline and three blowing flap configurations are presented. The effects that the flap tip jets have on the structure of the flap side edge flow are discussed for each of the flap configurations tested. The results indicate that blowing air from a slot located along the top surface of the flap greatly weakened the top vortex system and pushed it further off the top surface. Blowing from the bottom flap surface kept the strong side vortex further outboard while blowing from the side surface only strengthened the vortex system or accelerated the merging of the side vortex to the flap top surface. It is concluded that blowing from the top or bottom surfaces of the flap may lead to a reduction of flap side edge noise.

  12. Blowing Snow Over the Antarctic Plateau

    NASA Technical Reports Server (NTRS)

    Mahesh, Ashwin; Eager, Rebecca; Campbell, James R.; Spinhirne, James D.

    2002-01-01

    Studies of blowing snow over Antarctica have been limited greatly by the remoteness and harsh conditions of the region. Space-based observations are also of lesser value than elsewhere, given the similarities between ice clouds and snow-covered surfaces, both at infrared and visible wavelengths. It is only in recent years that routine ground-based observation programs have acquired sufficient data to overcome the gap in our understanding of surface blowing snow. In this paper, observations of blowing snow from visual observers' records as well as ground-based spectral and lidar programs at South Pole station are analyzed to obtain the first climatology of blowing snow over the Antarctic plateau. Occurrence frequencies, correlation with wind direction and speed, typical layer heights, as well as optical depths are determined. Blowing snow is seen in roughly one third of the visual observations and occurs under a narrow range of wind directions. The near-surface layers typically a few hundred meters thick emit radiances similar to those from thin clouds. Because blowing snow remains close to the surface and is frequently present, it will produce small biases in space-borne altimetry; these must be properly estimated and corrected.

  13. Stretching: Does It Help?

    ERIC Educational Resources Information Center

    Vardiman, Phillip; Carrand, David; Gallagher, Philip M.

    2010-01-01

    Stretching prior to activity is universally accepted as an important way to improve performance and help prevent injury. Likewise, limited flexibility has been shown to decrease functional ability and predispose a person to injuries. Although this is commonly accepted, appropriate stretching for children and adolescents involved with sports and…

  14. Stretch Band Exercise Program

    ERIC Educational Resources Information Center

    Skirka, Nicholas; Hume, Donald

    2007-01-01

    This article discusses how to use stretch bands for improving total body fitness and quality of life. A stretch band exercise program offers a versatile and inexpensive option to motivate participants to exercise. The authors suggest practical exercises that can be used in physical education to improve or maintain muscular strength and endurance,…

  15. Tire blow-outs and motorway accidents.

    PubMed

    Martin, Jean-Louis; Laumon, Bernard

    2005-03-01

    During the period from 1996 to 2002, 60,397 vehicles were involved in crashes with property damage and/or injury on a French motorway network of 2000 km. It was observed that 6.7% of these accidents involved tire blow-outs. In 87% of cases, only one vehicle was involved in the accident. Tire blow-outs occurred in 6.5% of cars that represented more than 80% of the vehicles involved in crashes. The occurrence of this phenomenon is very high for vans (22%), though it concerns trucks less (2.5%). The proportion of tire blow-outs decreased from 1997, when it was 8.0%, to 5.9% in 2002. However, two main facts require examination: (1) On inter-urban motorways, crashes involving blow-outs of rear tires occur four times more frequently than for blow-outs of front tires. (2) The frequency of tire blow-outs is especially high for vans, and almost always involves rear tires. This higher frequency for rear tires is the result of two phenomena, which are indistinguishable given the data available: firstly, a four-wheel vehicle is more difficult to control if a blow-out occurs on a rear tire (confirmed experimentally); secondly, rear tires may be in poor condition more often than front tires, and so more prone to blow-outs. Consequently, users are strongly recommended to install the best tires on rear wheels. In practice, if only the front tires are replaced, which often occurs because they tend to be worn out more quickly than the rear ones (especially for front wheel drive vehicles), it is necessary to move the rear tires to the front and fit the new ones on the rear wheels. Very interesting technological developments are in progress that should reduce the number of tire blow-outs. However, considering the time necessary to renew the number of cars on the roads, this very simple and inexpensive recommendation should apply to all cars and especially to vans.

  16. Low-Speed Fan Noise Reduction With Trailing Edge Blowing

    NASA Technical Reports Server (NTRS)

    Sutliff, Daniel L.; Tweedt, Daniel L.; Fite, E. Brian; Envia, Edmane

    2002-01-01

    An experimental proof-of-concept test was conducted to demonstrate reduction of rotor-stator interaction noise through rotor-trailing edge blowing. The velocity deficit from the viscous wake of the rotor blades was reduced by injecting air into the wake from a trailing edge slot. Composite hollow rotor blades with internal flow passages were designed based on analytical codes modeling the internal flow. The hollow blade with interior guide vanes creates flow channels through which externally supplied air flows from the root of the blade to the trailing edge. The impact of the rotor wake-stator interaction on the acoustics was also predicted analytically. The Active Noise Control Fan, located at the NASA Glenn Research Center, was used as the proof- of-concept test bed. In-duct mode and farfield directivity acoustic data were acquired at blowing rates (defined as mass supplied to trailing edge blowing system divided by fan mass flow) ranging from 0.5 to 2.0 percent. The first three blade passing frequency harmonics at fan rotational speeds of 1700 to 1900 rpm were analyzed. The acoustic tone power levels (PWL) in the inlet and exhaust were reduced 11.5 and -0.1, 7.2 and 11.4, 11.8 and 19.4 PWL dB, respectively. The farfield tone power levels at the first three harmonics were reduced 5.4, 10.6, and 12.4 dB PWL. At selected conditions, two-component hotwire and stator vane unsteady surface pressures were acquired. These measurements illustrate the physics behind the noise reduction.

  17. Computational analysis of forebody tangential slot blowing

    NASA Technical Reports Server (NTRS)

    Gee, Ken; Agosta-Greenman, Roxana M.; Rizk, Yehia M.; Schiff, Lewis B.; Cummings, Russell M.

    1994-01-01

    An overview of the computational effort to analyze forebody tangential slot blowing is presented. Tangential slot blowing generates side force and yawing moment which may be used to control an aircraft flying at high-angle-of-attack. Two different geometries are used in the analysis: (1) The High Alpha Research Vehicle; and (2) a generic chined forebody. Computations using the isolated F/A-18 forebody are obtained at full-scale wind tunnel test conditions for direct comparison with available experimental data. The effects of over- and under-blowing on force and moment production are analyzed. Time-accurate solutions using the isolated forebody are obtained to study the force onset timelag of tangential slot blowing. Computations using the generic chined forebody are obtained at experimental wind tunnel conditions, and the results compared with available experimental data. This computational analysis compliments the experimental results and provides a detailed understanding of the effects of tangential slot blowing on the flow field about simple and complex geometries.

  18. Distributed upper-surface blowing concept

    NASA Technical Reports Server (NTRS)

    Fournier, P. G.; Coe, P. L., Jr.

    1976-01-01

    A low speed investigation was conducted in the Langley V/STOL tunnel to determine the powered lift aerodynamic performance of a distributed upper surface blown propulsive lift transport model. The model used blowing slots across the span of the wing to produce a thin jet efflux near the leading edge and at the knee of the trailing edge flap (internally blown jet flap). Results indicate that these concepts have both good propulsive related lift and low drag due to lift characteristics because of uniform spanwise propulsive thrust. The leading edge blowing concept provides low speed lift characteristics which are competitive with the flap-hinge-line blowing concept and does not require additional leading edge treatment for prevention of abrupt stall.

  19. Droplet-born air blowing: novel dissolving microneedle fabrication.

    PubMed

    Kim, Jung Dong; Kim, Miroo; Yang, Huisuk; Lee, Kwang; Jung, Hyungil

    2013-09-28

    The microneedle-mediated drug delivery system has been developed to provide painless self-administration of drugs in a patient-friendly manner. Current dissolving microneedle fabrication methods, however, require harsh conditions for biological drugs and also have problems standardizing the drug dose. Here, we suggested the droplet-born air blowing (DAB) method, which provides gentle (4-25 °C) and fast (≤10min) microneedle fabrication conditions without drug loss. The amount of drug in the microneedle can be controlled by the pressure and time of droplet dispenser and the air blowing shapes this droplet to the microneedle, providing a force sufficient to penetrate skin. Also, the introduction of a base structure of two layered DAB-microneedle could provide complete drug delivery without wasting of drug. The DAB-based insulin loaded microneedle shows similar bioavailability (96.6±2.4%) and down regulation of glucose level compared with subcutaneous injection. We anticipate that DAB described herein will be suitable to design dissolving microneedles for use in biological drug delivery to patients.

  20. Triceps stretch (image)

    MedlinePlus

    ... shoulder. Hold for 10 to 20 seconds, then switch sides. Alternate method: raise your arm over your ... elbow. Hold for 10 to 20 seconds, then switch sides. You should feel either of these stretches ...

  1. Development of polyimide foams with blowing agents

    NASA Technical Reports Server (NTRS)

    Gagliani, John (Inventor); Sorathia, Usman A. K. (Inventor); Lee, Raymond (Inventor)

    1985-01-01

    A method of preparing a polyimide foam which includes the steps of: preparing, foaming, and curing a precursor containing at least one alkyl ester of 3,3'4,4'-benzophenonetetracarboxylic acid; a meta- or para-substituted aromatic diamine; a heterocyclic diamine; an aliphatic diamine; and a solid blowing agent. The blowing agent is added to said precursor in a concentration which is sufficient to effect at least one of the following attributes of the foam: cell size, proportion of open cells, cell density, and indentation load deflection.

  2. 2. GENERAL VIEW OF BLOWING ENGINE HOUSE, LOOKING NORTH; BOILER ...

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

    2. GENERAL VIEW OF BLOWING ENGINE HOUSE, LOOKING NORTH; BOILER HOUSE ON LEFT; BLAST FURNACE, OVENS AND CASTING HOUSE BEYOND. - U.S. Steel Corporation, Clairton Works, Blast Furnace Blowing Engine Building, 400 State Street, Clairton, Allegheny County, PA

  3. Morphology and Mechanical Properties of Poly(Ethylene Terephthalate) Stretched Above the Glass Transition Temperature

    NASA Astrophysics Data System (ADS)

    Todorov, Lyudmil V.; Viana, Júlio C.

    2007-04-01

    This study presents an experimental investigation into the development of the strain-induced morphology of amorphous poly(ethylene terephthalate), PET, stretched above its glass transition temperature. The present work aims at: i) defining the most important processing parameters that govern the structure formation and its significance; ii) characterising the mechanical properties of uniaxial stretched glassy PET, as an approach for industrial stretch-blow moulding techniques; iii) establishing structure-properties relationships. Compression moulded amorphous PET was uniaxial stretched with variations of following stretching parameters: stretching temperature, Tst, stretching velocity, Vst, and stretching ratio, λst, that were varied in two levels according to a L8 Taguchi orthogonal array. The developed morphologies were observed by differential scanning calorimetry (DSC), birefringence and Wide-Angle X-ray Scattering (WAXS). The mechanical behaviour was assessed in tensile testing at 15 mm.min-1 and room temperature. The results were treated by a statistical ANOVA tool. A strong thermal and mechanical coupling is evidenced in the stretching process, significantly influencing the morphology development. The main stretching parameters controlling microstructure formation were defined. The relationships between the microstructure and mechanical properties were established too.

  4. Dinural patterns of blowing sand and dust

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The diurnal pattern of blowing sand results from a complex interaction between the sun, the atmosphere, and the sand surface. During the day, solar heating produces thermal instability, which enhances convective mixing of high momentum winds from the upper levels of the atmosphere to the surface la...

  5. 21 CFR 868.5220 - Blow bottle.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Blow bottle. 868.5220 Section 868.5220 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... that is intended for medical purposes to induce a forced expiration from a patient. The patient...

  6. 21 CFR 868.5220 - Blow bottle.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Blow bottle. 868.5220 Section 868.5220 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... that is intended for medical purposes to induce a forced expiration from a patient. The patient...

  7. 21 CFR 868.5220 - Blow bottle.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... that is intended for medical purposes to induce a forced expiration from a patient. The patient blows... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... system regulation in part 820 of this chapter, with the exception of § 820.180, with respect to...

  8. 21 CFR 868.5220 - Blow bottle.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... that is intended for medical purposes to induce a forced expiration from a patient. The patient blows... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... system regulation in part 820 of this chapter, with the exception of § 820.180, with respect to...

  9. Whistle-Blowing Intentions of Prospective Teachers: Education Evidence

    ERIC Educational Resources Information Center

    Gökçe, Asiye Toker

    2013-01-01

    This study investigates whistle-blowing intentions of prospective teachers. Firstly, overall ethical awareness of the participants was examined, and then their underlying ethical reasons of whistle-blowing were investigated. Besides, impact on the intention to blow whistle to internal or external parties offering their job guarantee were searched.…

  10. Drifting and blowing snow, measurements and modelling

    NASA Astrophysics Data System (ADS)

    Gordon, Mark

    2007-12-01

    Blowing snow is a frequent and significant winter weather event, and there is currently a need for more observations and measurements of blowing snow, especially in arctic and subarctic environments. A camera system has been developed to measure the size and velocity of blowing snow particles. A second camera system has been developed to measure the relative blowing snow density profile near the snow surface. These systems have been used, along with standard meteorological instruments and optical particle counters, during field campaigns at Franklin Bay, NWT, and at Churchill, MB. An electric field mill was also deployed at Franklin Bay. Results demonstrate that the particle diameters follow a Gamma distribution with 103 < d¯ < 172 mum below a height of 0.15 m and 120 < d¯ < 154 mum between 0.2 m and 1.1 m. Within the saltation layer, the mass density can be approximated by a power-law (rhos ∝ z -gamma) with an exponent of gamma ≈ 1.5 for z < 40 mm. Between 40 < z < 100 mm, in the lower suspension layer, the value of the exponent increases to a range of 1.5 < gamma < 8. At greater heights, z > 100 mm, the exponent approaches gamma ≈ l. The height of saltation shows a very weak dependence on the friction velocity, a strong dependence on temperature and relative humidity, and a weak dependence on snow age. Electric field strengths as high as 2000 V m-1 were measured at a height of 0.5 m. A model to determine electric field strength based on the distribution of blowing snow particles shows a weak agreement with measurements. Results suggest the charge is most likely generated due to either fragmentation or asymmetric rubbing, which are both strongly dependent on wind speed. Modelling studies with the Canadian Land Surface Scheme (CLASS) and previous measurements of snow depth at Goose Bay, Hay River, the Beaufort Sea, Franklin Bay, and Resolute demonstrate that blowing snow sublimation can have a substantial effect on snow depth. Adding a blowing snow

  11. Numerical method for boundary layers with blowing - The exponential box scheme

    NASA Technical Reports Server (NTRS)

    El-Mistikawy, T. M.; Werle, M. J.

    1978-01-01

    The paper describes a new numerical scheme based on exponential difference operator concepts combined with Keller's (1968) box scheme approach to produce a stable second-order accurate finite-difference scheme for convection-diffusion problems arising in boundary layer flows in the presence of massive injection through a porous surface. The technique is demonstrated by application to the self-similar boundary layer equations with massive blowing at the surface.

  12. Control of Cavity Resonance Using Steady and Oscillatory Blowing

    NASA Technical Reports Server (NTRS)

    Lamp, Alison M.; Chokani, Ndaona

    1999-01-01

    An experimental study to investigate the effect of steady and oscillatory (with zero net mass flux) blowing on cavity resonance is undertaken. The objective is to study the basic mechanisms of the control of cavity resonance. An actuator is designed and calibrated to generate either steady blowing or oscillatory blowing with A zero net mass flux. The results of the experiment show that both steady and oscillatory blowing are effective, and reduce the amplitude of the dominant resonant mode by 1OdB. The oscillatory blowing is however found to be more superior in that the same effectiveness could be accomplished with a momentum coefficient an order of magnitude smaller than for steady blowing. The experiment also confirms the results of previous computations that suggest the forcing frequency for oscillatory blowing must not be at harmonic frequencies of the cavity resonant modes.

  13. Blow-down and blow-in of Inland`s No. 7 blast furnace

    SciTech Connect

    Ricketts, J.; Quisenberry, P.; Carter, W.

    1995-12-01

    After extensive and detailed planning, a mini-reline of the 13.7 meter No. 7 Blast Furnace was executed in November 1993. The furnace lining had 18 million metric tons of production and the bosh, belly and lower stack lining were being maintained through a scheduled grouting practice. The mini-reline was planned for 33 days and the reline work included (a) replacing the bosh, belly and lower stack alumina lining with graphite brick, (b) gunning the middle and upper stack, (c) rebuilding the furnace top, stove burners and tapholes and (d) minor repairs to other auxiliary equipment. During this 33 day reline period the two 8 meter furnaces could only produce 40% of the normal production requirement, therefore the blow-down, quench, salamander tap and blow-in activities were critical to meeting the planned schedule. The planning of these activities was started in the spring of 1993 and included review of Inland`s past blow-down and blow-in performance as well as bench marking the performance of other large blast furnaces in North America, Japan and Europe. The development of the 1993 procedures focused on opportunities to accelerate the blow-down, quench, salamander tap and blow-in as well as having a clean hearth and stack which could also save time during the demolition phase of the reline. Any time that could be saved in these activities directly translated to an early start-up and more plantwide production. This paper will cover the successful planning and implementation of these activities which resulted in a 2 day reduction in the reline schedule, an accelerated production curve and an earlier than planned use of PCI during blow-in.

  14. Stretch That Budget!

    ERIC Educational Resources Information Center

    Walker, John R.

    1976-01-01

    Discusses ways in which industrial education teachers can stretch their budgets, which include reducing waste to a minimum, keeping an accurate and up-to-date inventory, trading surplus or excess materials with neighboring schools, and planning programs more carefully. Money-saving tips concerned with metals, plastics, woods, and printing are also…

  15. An Implicit Finite Difference Solution to the Viscous Radiating Shock Layer with Strong Blowing. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Garrett, L. B.

    1971-01-01

    An implicit finite difference scheme is developed for the fully coupled solution of the viscous radiating stagnation line equations, including strong blowing. Solutions are presented for both air injection and carbon phenolic ablation products injection into air at conditions near the peak radiative heating point in an earth entry trajectory from interplanetary return missions. A detailed radiative transport code that accounts for the important radiative exchange processes for gaseous mixtures in local thermodynamic and chemical equilibrium is utilized.

  16. Divisional Air Defense: The Shield of Blows

    DTIC Science & Technology

    1992-12-19

    destroy missions. The early tactics used by the Hinds indicated a total lack of respect for the resistance fighters. The aircraft engaged the ground ...AD-A264 505 SDivisional Air Defense: The Shield of Blows DTI ELECTE MAY 19 1993 A Monograph U A by Major Cornell T. McGhee Air Defense Artillery...blank) " 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED Monograph 4. TITLE AND SUBTITLE "S. FUNDING NUMBERS Divisional Air Defense: The Shield of

  17. Stretching & Flexibility: An Interactive Encyclopedia of Stretching. [CD-ROM].

    ERIC Educational Resources Information Center

    2002

    This CD-ROM offers 140 different stretches in full-motion video sequences. It focuses on the proper techniques for overall physical fitness, injury prevention and rehabilitation, and 23 different sports (e.g., golf, running, soccer, skiing, climbing, football, and baseball). Topics include stretching for sports; stretching awareness and education…

  18. Effectiveness of Micro-Blowing Technique in Adverse Pressure Gradients

    NASA Technical Reports Server (NTRS)

    Welch, Gerard E.; Larosiliere, Louis M.; Hwang, Danny P.; Wood, Jerry R.

    2001-01-01

    The impact of the micro-blowing technique (MBT) on the skin friction and total drag of a strut in a turbulent, strong adverse-pressure-gradient flow is assessed experimentally over a range of subsonic Mach numbers (0.3 less than M less than 0.7) and reduced blowing fractions (0 less than or equal to 2F/C (sub f,o) less than or equal to 1.75). The MBT-treated strut is situated along the centerline of a symmetric 2-D diffuser with a static pressure rise coefficient of 0.6. In agreement with presented theory and earlier experiments in zero-pressure-gradient flows, the effusion of blowing air reduces skin friction significantly (e.g., by 60% at reduced blowing fractions near 1.75). The total drag of the treated strut with blowing is significantly lower than that of the treated strut in the limit of zero-blowing; further, the total drag is reduced below that of the baseline (solid-plate) strut, provided that the reduced blowing fractions are sufficiently high. The micro-blowing air is, however, deficient in streamwise momentum and the blowing leads to increased boundary-layer and wake thicknesses and shape factors. Diffuser performance metrics and wake surveys are used to discuss the impact of various levels of micro-blowing on the aerodynamic blockage and loss.

  19. Stretch-Oriented Polyimide Films

    NASA Technical Reports Server (NTRS)

    Hinkley, Jeffrey A.; Klinedinst, D.; Feuz, L.

    2000-01-01

    Two thermoplastic polyimides - one amorphous, the other crystallizable -- were subjected to isothermal stretching just above their glass transition temperatures. Room-temperature strengths in the stretch direction were greatly improved and, moduli increased up to 3.6-fold. Optimum stretching conditions were determined.

  20. Forebody tangential blowing for control at high angles of attack

    NASA Technical Reports Server (NTRS)

    Kroo, I.; Rock, S.; Roberts, L.

    1991-01-01

    A feasibility study to determine if the use of tangential leading edge blowing over the forebody could produce effective and practical control of the F-18 HARV aircraft at high angles of attack was conducted. A simplified model of the F-18 configuration using a vortex-lattice model was developed to obtain a better understanding of basic aerodynamic coupling effects and the influence of forebody circulation on lifting surface behavior. The effect of tangential blowing was estimated using existing wind tunnel data on normal forebody blowing and analytical studies of tangential blowing over conical forebodies. Incorporation of forebody blowing into the flight control system was investigated by adding this additional yaw control and sideforce generating actuator into the existing F-18 HARV simulation model. A control law was synthesized using LQG design methods that would schedule blowing rates as a function of vehicle sideslip, angle of attack, and roll and yaw rates.

  1. Stretched View Showing 'Victoria'

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Stretched View Showing 'Victoria'

    This pair of images from the panoramic camera on NASA's Mars Exploration Rover Opportunity served as initial confirmation that the two-year-old rover is within sight of 'Victoria Crater,' which it has been approaching for more than a year. Engineers on the rover team were unsure whether Opportunity would make it as far as Victoria, but scientists hoped for the chance to study such a large crater with their roving geologist. Victoria Crater is 800 meters (nearly half a mile) in diameter, about six times wider than 'Endurance Crater,' where Opportunity spent several months in 2004 examining rock layers affected by ancient water.

    When scientists using orbital data calculated that they should be able to detect Victoria's rim in rover images, they scrutinized frames taken in the direction of the crater by the panoramic camera. To positively characterize the subtle horizon profile of the crater and some of the features leading up to it, researchers created a vertically-stretched image (top) from a mosaic of regular frames from the panoramic camera (bottom), taken on Opportunity's 804th Martian day (April 29, 2006).

    The stretched image makes mild nearby dunes look like more threatening peaks, but that is only a result of the exaggerated vertical dimension. This vertical stretch technique was first applied to Viking Lander 2 panoramas by Philip Stooke, of the University of Western Ontario, Canada, to help locate the lander with respect to orbiter images. Vertically stretching the image allows features to be more readily identified by the Mars Exploration Rover science team.

    The bright white dot near the horizon to the right of center (barely visible without labeling or zoom-in) is thought to be a light-toned outcrop on the far wall of the crater, suggesting that the rover can see over the low rim of Victoria. In figure 1, the northeast and southeast rims are labeled

  2. Reducing secondary losses by blowing cold air in a turbine

    NASA Technical Reports Server (NTRS)

    Koschel, W.

    1977-01-01

    Local blowing on the profile suction side of the turbine guide wheel blades can be effective in preventing the propagation of secondary flows that is, the transport of casing and hub boundary layers by pressure gradients. Some preliminary results on how the blowing should be accomplished in order to influence the secondary flows in the desired manner are given. The effectiveness of blowing is demonstrated. Blowing is also seen to be more effective than using boundary layer slots as far as diminishing losses in the rim zones is concerned.

  3. Development of an Automatic Blowing Snow station

    NASA Astrophysics Data System (ADS)

    Nishimura, K.

    2010-12-01

    On the Antarctic ice sheet, strong katabatic winds blow throughout the year and a large but unknown fraction of the snow which falls on it is removed continuously. This constitutes a significant factor in mass and energy balance and is all the more important when predicting the likely effects of global climate change. Further, recent experimental work has indicated that the snowdrift sublimation can lead to significant mass losses during strong winds and can be also an important factor in the surface mass balance of the Antarctic ice sheets. Nishimura and Nemoto (2005) carried out the blowing snow observations at Mizuho station, Antarctica in 2000 with the snow particle counters (SPC) that can sense not only the number of snow particles but also their diameters. SPC worked properly and the data obtained revealed profiles of mass flux and particle size distributions as a function of the friction velocity. However, the SPC requires rather high power supply and the data is stored in PC; it is not always suitable for the unmanned observations under the severe Antarctic conditions. Thus, we have developed a simpler device by measuring the attenuation of the light intensity, which strongly depends on the blowing snow flux. A small wind turbine and a cold-proof buttery were utilized as a power source. Firstly, its performance was tested with comparing the SPC in a cold wind tunnel system and it proved adequately fit for practical use by combining the output of the anemometer. In 2009/2010 winter, three systems have been set at Ishikari, Col du Lac blanc in France, and S17 near Syowa station in Antarctica, and the tests are still continuing.

  4. Blowing Agents for Fabrication of Polyimide Foams

    NASA Technical Reports Server (NTRS)

    Gagliani, J.; Sorathia, U. A. K.; Lee, R.

    1982-01-01

    Polyimide resin can be foamed by agent generated within matrix of powder precursor. Blowing agent is mixture of water and methanol that are byproducts of condensation/polymerization reaction in resin. Expansion of these two compounds produces cellular foam structure that is flexible and resilient but that tends to have very-fine cellular structure. More open structure with lower density can be attained by modifying mechanism of foam formation. Foams have applications as fillers for seat cushions, wall panels, floor sheets, and thermal and acoustical insulation.

  5. Nonlinear flight control using forebody tangential blowing

    NASA Astrophysics Data System (ADS)

    Takahara, Yuji

    This dissertation is on the development and experimental demonstration of a new nonlinear approach to developing control laws for the lateral-directional dynamics of aircraft at high angles of attack using Forebody Tangential Blowing (FTB). FTB is a pneumatic device that modifies the vortical flow over the forebody. The modified vortical flow in turn creates roll and yaw moments for control. FTB has been shown to be a very powerful means of generating forces and moments on aircraft operating in flight regimes where the effectiveness of conventional aerodynamic surfaces is reduced (e.g. post stall). Consequently, it provides a mechanism that could greatly expand the flight envelope of future aircraft systems. One major factor that currently limits the use of FTB is that it is a highly nonlinear and uncertain effector. In particular, FTB can provide very powerful effects (e.g. forces and moments) at low levels of blowing but the characteristic relating input to output is highly nonlinear in this region. On the other hand, if higher levels of blowing are used, the characteristics become well behaved. Hence, the trade-off between robustness and control usage is particularly acute. The goal of this thesis is to develop a technique that will yield for the first time robust control at small levels of blowing thus enabling a new level of efficiency in the use of FTB as a device for flight control at high angles of attack. The approach developed is based on combining High-Gain Control (HGC) and Lyapunov techniques. By employing a robust inversion of uncertain static nonlinearities, the new control law can be applied to a class of systems represented by a cascade connection of a nonlinear system and an uncertain linear system. In particular, the nonlinear control approach is applied to the control of an aircraft utilizing FTB and can fully exploit the FTB efficiency. Simulation and experimental results are provided that demonstrate the effectiveness of the approach. Further

  6. THIRD-GENERATION FOAM BLOWING AGENTS FOR FOAM INSULATION

    EPA Science Inventory

    The report gives results of a study of third-generation blowing agents for foam insulation. (NOTE: the search for third-generation foam blowing agents has led to the realization that, as the number of potential substitutes increases, new concerns, such as their potential to act a...

  7. 1. GENERAL VIEW OF BLOWING ENGINE HOUSE LOOKING NORTH; THREE ...

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

    1. GENERAL VIEW OF BLOWING ENGINE HOUSE LOOKING NORTH; THREE TANKS AT RIGHT ADJACENT TO BUILDING ARE FOR SOFTENING BOILER WATER (LIME TREATMENT): TRUNCATED AND BOILER HOUSE, ONE OVEN AND ORE BRIDGE AT LEFT. - U.S. Steel Corporation, Clairton Works, Blast Furnace Blowing Engine Building, 400 State Street, Clairton, Allegheny County, PA

  8. 74. View of small steam tank used in 'blowing down' ...

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

    74. View of small steam tank used in 'blowing down' or cleaning boilers; in background can be seen the bottom of cylindrical water tank located in setback at southeast corner of blowing engine house. - Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham, Jefferson County, AL

  9. Use of cooling tower blow down in ethanol fermentation.

    PubMed

    Rajagopalan, N; Singh, V; Panno, B; Wilcoxon, M

    2010-01-01

    Reducing water consumption in bioethanol production conserves an increasingly scarce natural resource, lowers production costs, and minimizes effluent management issues. The suitability of cooling tower blow down water for reuse in fermentation was investigated as a means to lower water consumption. Extensive chemical characterization of the blow down water revealed low concentrations of toxic elements and total dissolved solids. Fermentation carried out with cooling tower blow down water resulted in similar levels of ethanol and residual glucose as a control study using deionized water. The study noted good tolerance by yeast to the specific scale and corrosion inhibitors found in the cooling tower blow down water. This research indicates that, under appropriate conditions, reuse of blow down water from cooling towers in fermentation is feasible.

  10. Broadband Noise Reduction of a Low-Speed Fan Noise Using Trailing Edge Blowing

    NASA Technical Reports Server (NTRS)

    Sutliff, Daniel L.

    2005-01-01

    An experimental proof-of-concept test was conducted to demonstrate reduction of rotor-stator interaction noise through the use of rotor-trailing edge blowing. The velocity deficit from the viscous wake of the rotor blades was reduced by injecting air into the wake from a continuous trailing edge slot. Hollow blades with interior guide vanes create flow channels through which externally supplied air flows from the blade root to the trailing edge. A previous paper documented the substantial tonal reductions of this Trailing Edge Rotor Blowing (TERB) fan. This report documents the broadband characteristics of TERB. The Active Noise Control Fan (ANCF), located at the NASA Glenn Research Center, was used as the proof-of-concept test bed. Two-component hotwire data behind the rotor, unsteady surface pressures on the stator vane, and farfield directivity acoustic data were acquired at blowing rates of 1.1, 1.5, and 1.8 percent of the total fan mass flow. The results indicate a substantial reduction in the rotor wake turbulent velocity and in the stator vane unsteady surface pressures. Based on the physics of the noise generation, these indirect measurements indicate the prospect of broadband noise reduction. However, since the broadband noise generated by the ANCF is rotor-dominated, any change in the rotor-stator interaction broadband noise levels is barely distinguishable in the farfield measurements.

  11. Experiments in Aircraft Roll-Yaw Control using Forebody Tangential Blowing

    NASA Technical Reports Server (NTRS)

    Pedreiro, Nelson

    1997-01-01

    Advantages of flight at high angles of attack include increased maneuverability and lift capabilities. These are beneficial not only for fighter aircraft, but also for future supersonic and hypersonic transport aircraft during take-off and landing. At high angles of attack the aerodynamics of the vehicle are dominated by separation, vortex shedding and possibly vortex breakdown. These phenomena severely compromise the effectiveness of conventional control surfaces. As a result, controlled flight at high angles of attack is not feasible for current aircraft configurations. Alternate means to augment the control of the vehicle at these flight regimes are therefore necessary. The present work investigates the augmentation of an aircraft flight control system by the injection of a thin sheet of air tangentially to the forebody of the vehicle. This method, known as Forebody Tangential Blowing (FTB), has been proposed as an effective means of increasing the controllability of aircraft at high angles of attack. The idea is based on the fact that a small amount of air is sufficient to change the separation lines on the forebody. As a consequence, the strength and position of the vortices are altered causing a change on the aerodynamic loads. Although a very effective actuator, forebody tangential blowing is also highly non-linear which makes its use for aircraft control very difficult. In this work, the feasibility of using FTB to control the roll-yaw motion of a wind tunnel model was demonstrated both through simulations and experimentally. The wind tunnel model used in the experiments consists of a wing-body configuration incorporating a delta wing with 70-degree sweep angle and a cone-cylinder fuselage. The model is equipped with forebody slots through which blowing is applied. There are no movable control surfaces, therefore blowing is the only form of actuation. Experiments were conducted at a nominal angle of attack of 45 degrees. A unique apparatus that constrains

  12. Pulsed single-blow regenerator testing

    NASA Technical Reports Server (NTRS)

    Oldson, J. C.; Knowles, T. R.; Rauch, J.

    1992-01-01

    A pulsed single-blow method has been developed for testing of Stirling regenerator materials performance. The method uses a tubular flow arrangement with a steady gas flow passing through a regenerator matrix sample that packs the flow channel for a short distance. A wire grid heater spanning the gas flow channel is used to heat a plug of gas by approximately 2 K for approximately 350 ms. Foil thermocouples monitor the gas temperature entering and leaving the sample. Data analysis based on a 1D incompressible-flow thermal model allows the extraction of Stanton number. A figure of merit involving heat transfer and pressure drop is used to present results for steel screens and steel felt. The observations show a lower figure of merit for the materials tested than is expected based on correlations obtained by other methods.

  13. Upper surface blowing aerodynamic and acoustic characteristics

    NASA Technical Reports Server (NTRS)

    Ryle, D. M., Jr.; Braden, J. A.; Gibson, J. S.

    1977-01-01

    Aerodynamic performance at cruise, and noise effects due to variations in nacelle and wing geometry and mode of operation are studied using small aircraft models that simulate upper surface blowing (USB). At cruise speeds ranging from Mach .50 to Mach .82, the key determinants of drag/thrust penalties are found to be nozzle aspect ratio, boattailing angle, and chordwise position; number of nacelles; and streamlined versus symmetric configuration. Recommendations are made for obtaining favorable cruise configurations. The acoustic studies, which concentrate on the noise created by the jet exhaust flow and its interaction with wing and flap surfaces, isolate several important sources of USB noise, including nozzle shape, exit velocity, and impingement angle; flow pathlength; and flap angle and radius of curvature. Suggestions for lessening noise due to trailing edge flow velocity, flow pathlength, and flow spreading are given, though compromises between some design options may be necessary.

  14. Bernoulli Suction Effect on Soap Bubble Blowing?

    NASA Astrophysics Data System (ADS)

    Davidson, John; Ryu, Sangjin

    2015-11-01

    As a model system for thin-film bubble with two gas-liquid interfaces, we experimentally investigated the pinch-off of soap bubble blowing. Using the lab-built bubble blower and high-speed videography, we have found that the scaling law exponent of soap bubble pinch-off is 2/3, which is similar to that of soap film bridge. Because air flowed through the decreasing neck of soap film tube, we studied possible Bernoulli suction effect on soap bubble pinch-off by evaluating the Reynolds number of airflow. Image processing was utilized to calculate approximate volume of growing soap film tube and the volume flow rate of the airflow, and the Reynolds number was estimated to be 800-3200. This result suggests that soap bubbling may involve the Bernoulli suction effect.

  15. Hypersonic Boundary Layer Measurements with Variable Blowing Rates Using Molecular Tagging Velocimetry

    NASA Technical Reports Server (NTRS)

    Bathel, Brett F.; Danehy, Paul M.; Johansen, Craig T.; Jones, Stephen B.; Goyne, Christopher P.

    2012-01-01

    Measurements of mean and instantaneous streamwise velocity profiles in a hypersonic boundary layer with variable rates of mass injection (blowing) of nitrogen dioxide (NO2) were obtained over a 10-degree half-angle wedge model. The NO2 was seeded into the flow from a slot located 29.4 mm downstream of the sharp leading edge. The top surface of the wedge was oriented at a 20 degree angle in the Mach 10 flow, yielding an edge Mach number of approximately 4.2. The streamwise velocity profiles and streamwise fluctuating velocity component profiles were obtained using a three-laser NO2->NO photolysis molecular tagging velocimetry method. Observed trends in the mean streamwise velocity profiles and profiles of the fluctuating component of streamwise velocity as functions of the blowing rate are described. An effort is made to distinguish between the effect of blowing rate and wall temperature on the measured profiles. An analysis of the mean velocity profiles for a constant blowing rate is presented to determine the uncertainty in the measurement for different probe laser delay settings. Measurements of streamwise velocity were made to within approximately 120 gm of the model surface. The streamwise spatial resolution in this experiment ranged from 0.6 mm to 2.6 mm. An improvement in the spatial precision of the measurement technique has been made, with spatial uncertainties reduced by about a factor of 2 compared to previous measurements. For the quiescent flow calibration measurements presented, uncertainties as low as 2 m/s are obtained at 95% confidence for long delay times (25 gs). For the velocity measurements obtained with the wind tunnel operating, average single-shot uncertainties of less than 44 m/s are obtained at 95% confidence with a probe laser delay setting of 1 gs. The measurements were performed in the 31-inch Mach 10 Air Tunnel at the NASA Langley Research Center.

  16. African Dust Blows over the Caribbean

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Shuttle astronauts frequently track Saharan dust storms as they blow from north Africa across the Atlantic Ocean. Dust palls blowing from Africa take about a week to cross the Atlantic. Recently, researchers have linked Saharan dust to coral disease, allergic reactions in humans, and red tides. The top photograph, a classic image showing African dust over the Caribbean, was taken at a time when few scientists had considered the possibility. The image was taken by Space Shuttle astronauts on July 11, 1994 (STS065-75-47). This photograph looks southwest over the northern edge of a large trans-Atlantic dust plume that blew off the Sahara desert in Africa. In this view, Caicos Island in the Bahamas and the mountainous spines of Haiti are partly obscured by the dust. Closer to the foreground, (about 26 degrees north latitude), the skies are clear. The lower photograph (STS105-723-7) was taken by Space Shuttle astronauts while docked to the International Space Station on August 19, 2001. The spacecraft is over the Atlantic Ocean at roughly 45oN, 60oW. The astronauts were looking obliquely to the south; the boundaries of the dust plumes can be traced visually by the abrupt change from clear to hazy atmosphere-the hazy line marks the northern edge of the dust pall near the Caribbean. Images provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  17. Control of VR-7 Dynamic Stall by Strong Steady Blowing

    NASA Technical Reports Server (NTRS)

    Weaver, D.; McAlister, K. W.; Tso, J.

    2004-01-01

    An experiment was performed in a water tunnel on a Boeing-Vertol VR-7 airfoil to study the effects of tangential blowing over the upper surface. Blowing was applied at the quarter-chord location during sinusoidal pitching oscillations described by alpha = alpha(sub m) + 10 deg sin omega t. Results were obtained for a Reynolds number of 1 x 10(exp 5), mean angles of 10 and 15 deg, reduced frequencies ranging from 0.005 to 0.15, and blowing rates from C(sub mu) = 0.16 to 0.66. Unsteady lift, drag, and pitching moment loads are reported, along with fluorescent-dye flow visualizations. Strong steady blowing was found to prevent the bursting of the leading-edge separation bubble at several test points. When this occurred, the lift was increased significantly, stall was averted, and the shape of the moment response showed a positive damping in pitch. In almost all cases, steady blowing reduced the hysteresis amplitudes present in the loads, but the benefits diminished as the reduced frequency and mean angle of oscillation increased. A limited number of pulsed blowing cases indicated that for low blowing rates, the greatest gains were achieved at F(sup +) = 0.9.

  18. INTERIOR VIEW SHOWING QBOP FURNACE IN BLOW. OXYGEN AND NATURAL ...

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

    INTERIOR VIEW SHOWING Q-BOP FURNACE IN BLOW. OXYGEN AND NATURAL GAS ARE BLOWN INTO THE FURNACE THROUGH THE TUYERES TO CHARGE 460,000 LBS. OF HOT METAL, 100,000 LBS. OF SCRAP WITH 30,000 LBS. OF LIME. BLOW TIME IS 16 MINUTES. THE TIME TO BLOW AND TAP THE FURNACES OF THE RESULTING 205,000 TONS OF STEEL AND SLAG IS 35 MINUTES. - U.S. Steel, Fairfield Works, Q-Bop Furnace, North of Valley Road & West of Ensley, Pleasant Grove Road, Fairfield, Jefferson County, AL

  19. To stretch or not to stretch: the role of stretching in injury prevention and performance.

    PubMed

    McHugh, M P; Cosgrave, C H

    2010-04-01

    Stretching is commonly practiced before sports participation; however, effects on subsequent performance and injury prevention are not well understood. There is an abundance of literature demonstrating that a single bout of stretching acutely impairs muscle strength, with a lesser effect on power. The extent to which these effects are apparent when stretching is combined with other aspects of a pre-participation warm-up, such as practice drills and low intensity dynamic exercises, is not known. With respect to the effect of pre-participation stretching on injury prevention a limited number of studies of varying quality have shown mixed results. A general consensus is that stretching in addition to warm-up does not affect the incidence of overuse injuries. There is evidence that pre-participation stretching reduces the incidence of muscle strains but there is clearly a need for further work. Future prospective randomized studies should use stretching interventions that are effective at decreasing passive resistance to stretch and assess effects on subsequent injury incidence in sports with a high prevalence of muscle strains.

  20. Dynamic stretching and golf swing performance.

    PubMed

    Moran, K A; McGrath, T; Marshall, B M; Wallace, E S

    2009-02-01

    The aim of the present study was to examine the effect of dynamic stretching, static stretching and no stretching, as part of a general warm-up, on golf swing performance with a five-iron. Measures of performance were taken 0 min, 5 min, 15 min and 30 min after stretching. Dynamic stretching produced significantly greater club head speeds than both static stretching (Delta=1.9m.s (-1); p=0.000) and no stretching (Delta=1.7 m.s (-1); p=0.000), and greater ball speeds than both static stretching (Delta=3.5m.s (-1); p=0.003) and no stretching (Delta=3.3m.s (-1); p=0.001). Dynamic stretching produced significantly straighter swing-paths than both static stretching (Delta=-0.61 degrees , p=0.000) and no stretching (Delta=-0.72 degrees , p=0.01). Dynamic stretching also produced more central impact points than the static stretch (Delta=0.7 cm, p=0.001). For the club face angle, there was no effect of either stretch or time. For all of the variables measured, there was no significant difference between the static stretch and no stretch conditions. All of the results were unaffected by the time of measurement after stretching. The results indicate that dynamic stretching should be used as part of a general warm-up in golf.

  1. 46 CFR 162.018-5 - Blow-down adjustment and popping tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 6 2014-10-01 2014-10-01 false Blow-down adjustment and popping tolerance. 162.018-5... Compressed Gas § 162.018-5 Blow-down adjustment and popping tolerance. (a) Safety relief valves shall be so... adjustable blow-down construction shall be adjusted to close after blowing down not more than 5 percent...

  2. 46 CFR 162.018-5 - Blow-down adjustment and popping tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 6 2013-10-01 2013-10-01 false Blow-down adjustment and popping tolerance. 162.018-5... Compressed Gas § 162.018-5 Blow-down adjustment and popping tolerance. (a) Safety relief valves shall be so... adjustible blow-down construction shall be adjusted to close after blowing down not more than 5 percent...

  3. 46 CFR 162.018-5 - Blow-down adjustment and popping tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 6 2012-10-01 2012-10-01 false Blow-down adjustment and popping tolerance. 162.018-5... Compressed Gas § 162.018-5 Blow-down adjustment and popping tolerance. (a) Safety relief valves shall be so... adjustible blow-down construction shall be adjusted to close after blowing down not more than 5 percent...

  4. 46 CFR 162.018-5 - Blow-down adjustment and popping tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Blow-down adjustment and popping tolerance. 162.018-5... Compressed Gas § 162.018-5 Blow-down adjustment and popping tolerance. (a) Safety relief valves shall be so... adjustible blow-down construction shall be adjusted to close after blowing down not more than 5 percent...

  5. 46 CFR 162.018-5 - Blow-down adjustment and popping tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 6 2011-10-01 2011-10-01 false Blow-down adjustment and popping tolerance. 162.018-5... Compressed Gas § 162.018-5 Blow-down adjustment and popping tolerance. (a) Safety relief valves shall be so... adjustible blow-down construction shall be adjusted to close after blowing down not more than 5 percent...

  6. 40. LOOKING EAST IN BLOW ENGINE HOUSE No. 2 AT ...

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

    40. LOOKING EAST IN BLOW ENGINE HOUSE No. 2 AT CASING FOR CENTRIFUGAL TURBOBLOWER No. 3. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  7. 37. INTERIOR VIEW OF BLOW ENGINE HOUSE No. 2 LOOKING ...

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

    37. INTERIOR VIEW OF BLOW ENGINE HOUSE No. 2 LOOKING EAST. CENTRIFUGAL TURBOBLOWER No. 1 IN FOREGROUND. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  8. 79. View inside blowing engine room looking down walkway with ...

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

    79. View inside blowing engine room looking down walkway with engine flywheels at left. - Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham, Jefferson County, AL

  9. A theory for lateral wing-tip blowing

    NASA Technical Reports Server (NTRS)

    Tavella, D.; Roberts, L.

    1985-01-01

    The concept of lateral blowing consists in utilizing thin jets of air, which are ejected in the spanwise direction from slots at the tips of straight and swept wings, or along the leading edges of delta wings, to generate aerodynamic forces without the assistance of deflecting solid surfaces. For weak intensities of blowing the so-generated forces could be used for roll and lateral control of aircraft. In this work a theory for this concept as applied to straight wings is presented, revealing the analytical relationship between blowing and aerodynamic forces. The approach is based on perturbing the span of an elliptically loaded wing. Scaling laws involving blowing intensity, aspect ratio, and angle of attack are derived and compared with experiments. It is concluded that this concept has potential as a novel roll and lateral control device.

  10. 72. View of reservoir adjacent to south wall of blowing ...

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

    72. View of reservoir adjacent to south wall of blowing engine house where water from furnaces was allowed to cool. - Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham, Jefferson County, AL

  11. The transient roll moment response due to forebody tangential blowing at high angles of attack

    NASA Astrophysics Data System (ADS)

    Chow, Jonathan Kwokching

    The sustained ability for controlled flight at high angles of attack is desirable for future aircraft. For combat aircraft, enhancing maneuverability is important to increasing its survivability. For future supersonic commercial aircraft, an increase in lift at high angles of attack leads to improved performance during take-offs and landing, and a reduction in noise pollution. However, nonlinear and unsteady phenomena, such as flow separation and vortex shedding dominate the aerodynamics in the high angle of attack regime. These phenomena cause the onset of lateral loads and decrease the effectiveness of conventional control surfaces. For conventional aircraft, controlled flight at high angle of attack is difficult or unfeasible without augmented means of control and a good understanding of their impact on vehicle characteristics and dynamics. The injection of thin sheets of air tangentially to the forebody of the vehicle has been found to be an extremely promising method for augmenting the control of a flight vehicle at high angles of attack. Forebody Tangential Blowing (FTB) allows the flow structure to be altered in a rational manner and increase the controllability of the vehicle under these flight conditions. The feasibility of using FTB to control the roll-yaw motion of flight vehicles has been demonstrated. Existing knowledge of FTB's nonlinear impact on the aerodynamic moment responses is limited. Currently available dynamic models predict the general trends in the behavior but do not capture important transient effects that dominate the responses when small amounts of blowing is used. These transients can be large in comparison to the steady-state values. This thesis summarizes the experimental and theoretical results of an investigation into the transient effects of Forebody Tangential Blowing. The relationship between the aerodynamic roll moment, vortical flowfield, and blowing strength is examined to obtain a fundamental understanding of the physics of

  12. Experiments in aircraft roll-yaw control using forebody tangential blowing

    NASA Astrophysics Data System (ADS)

    Pedreiro, Nelson

    Flight at high angles of attack can provide improved maneuverability for fighter aircraft and increased lift capabilities for future supersonic and hypersonic transport aircraft during take-off and landing. At high angles of attack the aerodynamics of the vehicle are dominated by separation, vortex shedding and breakdown, which compromise the effectiveness of conventional control surfaces. As a result, controlled flight at high angles of attack is not feasible for current aircraft configurations. Alternate means to augment the control of the vehicle at these flight regimes are therefore necessary. In this work, the feasibility of using Forebody Tangential Blowing to control the roll-yaw motion of a wind tunnel model at high angles of attack is demonstrated. The method consists of injecting a thin sheet of air tangentially to the forebody of the vehicle to change the separation lines over the forebody and alter the aerodynamic loads. A unique model was developed that describes the unsteady aerodynamic moments generated by both vehicle motion and the applied blowing. This aerodynamic model is sufficiently detailed to predict transient motion of the wind-tunnel model, and is simple enough to be suitable for control logic design and implementation. Successful closed-loop control was demonstrated experimentally for a delta wing body model with a cone-cylinder fuselage. Experiments were performed at 45 degrees nominal angle of attack. At this condition, the natural motion of the system is divergent. A discrete vortex method was developed to help understand the main physics of the flow. The method correctly captures the interactions between forebody and wing vortices. Moreover, the trends in static loads and flow structure are correctly represented. Flow visualization results revealed the vortical structure of the flow to be asymmetric even for symmetric flight conditions. The effects of blowing, roll and yaw angles on the flow structure were determined. It was shown that

  13. Polypropylenes foam consisting of thermally expandable microcapsule as blowing agent

    NASA Astrophysics Data System (ADS)

    Jeoung, Sun Kyung; Hwang, Ye Jin; Lee, Hyun Wook; Kwak, Sung Bok; Han, In-Soo; Ha, Jin Uk

    2016-03-01

    The structure of thermally expandable microcapsule (TEMs) is consisted of a thermoplastic shell which is filled with liquid hydrocarbon at core. The shell of TEMs becomes soft when the temperature is higher than boiling temperature of liquid hydrocarbon. The shell of TEMs is expanded under the high temperature because the inner pressure of TEMs is increased by vaporization of hydrocarbon core. Therefore, the TEMs are applicable for blowing agents and light weight fillers. In this research, we fabricated the polypropylene (PP) foam by using the TEMs and chemical blowing agents and compared to their physical properties. The density of the specimen was decreased when the contents of chemical blowing agents and TEMs were increased. In addition, the mechanical properties (i.e. tensile strength and impact strength) of specimens were deteriorated with increasing amount of chemical blowing agents and TEMs. However, PP foam produced with TEMs showed higher impact strength than the one with the chemical blowing agent. In order to clarify the dependence of impact strength of PP foam as the blowing agent, the morphology difference of the PP foams was investigated. Expanding properties of PP foams produced with TEMs was changed with TEMs content of PP foams. Processing conditions also influenced the mechanical properties of PP foam containing TEMs.

  14. Hydraulic fracture during epithelial stretching

    PubMed Central

    Casares, Laura; Vincent, Romaric; Zalvidea, Dobryna; Campillo, Noelia; Navajas, Daniel; Arroyo, Marino; Trepat, Xavier

    2015-01-01

    The origin of fracture in epithelial cell sheets subject to stretch is commonly attributed to excess tension in the cells’ cytoskeleton, in the plasma membrane, or in cell-cell contacts. Here we demonstrate that for a variety of synthetic and physiological hydrogel substrates the formation of epithelial cracks is caused by tissue stretching independently of epithelial tension. We show that the origin of the cracks is hydraulic; they result from a transient pressure build-up in the substrate during stretch and compression maneuvers. After pressure equilibration cracks heal readily through actomyosin-dependent mechanisms. The observed phenomenology is captured by the theory of poroelasticity, which predicts the size and healing dynamics of epithelial cracks as a function of the stiffness, geometry and composition of the hydrogel substrate. Our findings demonstrate that epithelial integrity is determined in a tension-independent manner by the coupling between tissue stretching and matrix hydraulics. PMID:25664452

  15. Hydraulic fracture during epithelial stretching

    NASA Astrophysics Data System (ADS)

    Casares, Laura; Vincent, Romaric; Zalvidea, Dobryna; Campillo, Noelia; Navajas, Daniel; Arroyo, Marino; Trepat, Xavier

    2015-03-01

    The origin of fracture in epithelial cell sheets subject to stretch is commonly attributed to excess tension in the cells’ cytoskeleton, in the plasma membrane, or in cell-cell contacts. Here, we demonstrate that for a variety of synthetic and physiological hydrogel substrates the formation of epithelial cracks is caused by tissue stretching independently of epithelial tension. We show that the origin of the cracks is hydraulic; they result from a transient pressure build-up in the substrate during stretch and compression manoeuvres. After pressure equilibration, cracks heal readily through actomyosin-dependent mechanisms. The observed phenomenology is captured by the theory of poroelasticity, which predicts the size and healing dynamics of epithelial cracks as a function of the stiffness, geometry and composition of the hydrogel substrate. Our findings demonstrate that epithelial integrity is determined in a tension-independent manner by the coupling between tissue stretching and matrix hydraulics.

  16. Strain softening in stretched DNA

    PubMed Central

    Luan, Binquan; Aksimentiev, Aleksei

    2010-01-01

    The microscopic mechanics of DNA stretching was characterized using extensive molecular dynamics simulations. By employing an anisotropic pressure control method, realistic force-extension dependences of effectively infinite DNA molecules were obtained. A coexistence of B- and S-DNA domains was observed during the overstretching transition. The simulations revealed that strain softening may occur in the process of stretching torsionally constrained DNA. The latter observation was qualitatively reconciled with available experimental data using a random-field Ising model. PMID:18851334

  17. Study of changes in the aerodynamic characteristics of the axisymmetric supersonic vehicle in case of gas blowing from the lateral surface

    NASA Astrophysics Data System (ADS)

    Kislovskiy, V. A.; Zvegintsev, V. I.

    2016-10-01

    Consider the flow around the axisymmetric supersonic vehicle with the use of gas jet blowing from the lateral surface. The blowing is made in series of points at different distances from the nose fairing. The aim of the work was to determine the changes in aerodynamic forces and the formation of the moment, when jet of gas blowing in different parts of the supersonic vehicle. The study was conducted by numerical modeling of different cases of injection. As a result, data were obtained which showed the degree of influence not only jet thrust from the jet flow, but same the impact of the redistribution of the flow by body surface on the formation of aerodynamic forces and moments.

  18. Failure During Sheared Edge Stretching

    NASA Astrophysics Data System (ADS)

    Levy, B. S.; van Tyne, C. J.

    2008-12-01

    Failure during sheared edge stretching of sheet steels is a serious concern, especially in advanced high-strength steel (AHSS) grades. The shearing process produces a shear face and a zone of deformation behind the shear face, which is the shear-affected zone (SAZ). A failure during sheared edge stretching depends on prior deformation in the sheet, the shearing process, and the subsequent strain path in the SAZ during stretching. Data from laboratory hole expansion tests and hole extrusion tests for multiple lots of fourteen grades of steel were analyzed. The forming limit curve (FLC), regression equations, measurement uncertainty calculations, and difference calculations were used in the analyses. From these analyses, an assessment of the primary factors that contribute to the fracture during sheared edge stretching was made. It was found that the forming limit strain with consideration of strain path in the SAZ is a major factor that contributes to the failure of a sheared edge during stretching. Although metallurgical factors are important, they appear to play a somewhat lesser role.

  19. Electrokinetic Stretching of Tethered DNA

    PubMed Central

    Ferree, Sean; Blanch, Harvey W.

    2003-01-01

    During electrophoretic separations of DNA in a sieving medium, DNA molecules stretch from a compact coil into elongated conformations when encountering an obstacle and relax back to a coil upon release from the obstacle. These stretching dynamics are thought to play an important role in the separation mechanism. In this article we describe a silicon microfabricated device to measure the stretching of tethered DNA in electric fields. Upon application of an electric field, electro-osmosis generates bulk fluid flow in the device, and a protocol for eliminating this flow by attaching a polymer brush to all silicon oxide surfaces is shown to be effective. Data on the steady stretching of DNA in constant electric fields is presented. The data corroborate the approximate theory of hydrodynamic equivalence, indicating that DNA is not free-draining in the presence of both electric and nonelectric forces. Finally, these data provide the first quantitative test of a Stigter and Bustamante's detailed theory of electrophoretic stretching of DNA without adjustable parameters. The agreement between theory and experiment is good. PMID:14507716

  20. Numerical study of delta wing leading edge blowing

    NASA Technical Reports Server (NTRS)

    Yeh, David; Tavella, Domingo; Roberts, Leonard

    1988-01-01

    Spanwise and tangential leading edge blowing as a means of controlling the position and strength of the leading edge vortices are studied by numerical solution of the three-dimensional Navier-Stokes equations. The leading edge jet is simulated by defining a permeable boundary, corresponding to the jet slot, where suitable boundary conditions are implemented. Numerical results are shown to compare favorably with experimental measurements. It is found that the use of spanwise leading edge blowing at moderate angle of attack magnifies the size and strength of the leading edge vortices, and moves the vortex cores outboard and upward. The increase in lift primarily comes from the greater nonlinear vortex lift. However, spanwise blowing causes earlier vortex breakdown, thus decreasing the stall angle. The effects of tangential blowing at low to moderate angles of attack tend to reduce the pressure peaks associated with leading edge vortices and to increase the suction peak around the leading edge, so that the integrated value of the surface pressure remains about the same. Tangential leading edge blowing in post-stall conditions is shown to re-establish vortical flow and delay vortex bursting, thus increasing C sub L sub max and stall angle.

  1. Near surface flow over a dimpled surface with blowing

    NASA Astrophysics Data System (ADS)

    Borchetta, Colby; Martin, Alexandre; Bailey, Sean

    2016-11-01

    Near surface flow over a perforated hexagonal dimpled surface was investigated experimentally. A parametric study was conducted among Reynolds numbers (Re) and Blowing Ratios (BR). The objective of this work was to investigate and understand the modifications to flow structure with blowing through snapshot Proper Orthogonal Decomposition (POD) analysis. At the lowest Re , the flow was laminar with a layering of shear layer structures formed by the ridges of the dimples. With no blowing, these structures remained attached to the surface, merging with downstream layers as they advect over it. POD analysis revealed that inversely correlated interaction between adjacent dimples was the most energetic mode. For the BR = 0 . 5 % case, a transition to turbulence was observed and, although similar structures were found, their interactions became more complex. For the blowing cases, shear layers structures became detached from the surface, forming larger structures further away from it which become the most energetic POD modes. As blowing was increased to nearly 1 % , a more developed turbulent state was observed. The shear layers became further displaced from the surface, and were shown to be less coherent across the flow direction. This research is supported by NASA Award NNX13AN04A.

  2. Wrinkled flames and geometrical stretch

    NASA Astrophysics Data System (ADS)

    Denet, Bruno; Joulin, Guy

    2011-07-01

    Localized wrinkles of thin premixed flames subject to hydrodynamic instability and geometrical stretch of uniform intensity (S) are studied. A stretch-affected nonlinear and nonlocal equation, derived from an inhomogeneous Michelson-Sivashinsky equation, is used as a starting point, and pole decompositions are used as a tool. Analytical and numerical descriptions of isolated (centered or multicrested) wrinkles with steady shapes (in a frame) and various amplitudes are provided; their number increases rapidly with 1/S>0. A large constant S>0 weakens or suppresses all localized wrinkles (the larger the wrinkles, the easier the suppression), whereas S<0 strengthens them; oscillations of S further restrict their existence domain. Self-similar evolutions of unstable many-crested patterns are obtained. A link between stretch, nonlinearity, and instability with the cutoff size of the wrinkles in turbulent flames is suggested. Open problems are evoked.

  3. Preventing Blow up by Convective Terms in Dissipative PDE's

    NASA Astrophysics Data System (ADS)

    Bilgin, Bilgesu; Kalantarov, Varga; Zelik, Sergey

    2016-09-01

    We study the impact of the convective terms on the global solvability or finite time blow up of solutions of dissipative PDEs. We consider the model examples of 1D Burger's type equations, convective Cahn-Hilliard equation, generalized Kuramoto-Sivashinsky equation and KdV type equations. The following common scenario is established: adding sufficiently strong (in comparison with the destabilizing nonlinearity) convective terms to equation prevents the solutions from blowing up in a finite time and makes the considered system globally well-posed and dissipative and for weak enough convective terms the finite time blow up may occur similar to the case, when the equation does not involve convective term. This kind of result has been previously known for the case of Burger's type equations and has been strongly based on maximum principle. In contrast to this, our results are based on the weighted energy estimates which do not require the maximum principle for the considered problem.

  4. A Purposeful Dynamic Stretching Routine

    ERIC Educational Resources Information Center

    Leon, Craig; Oh, Hyun-Ju; Rana, Sharon

    2012-01-01

    Dynamic stretching, which involves moving parts of the body and gradually increases range of motion, speed of movement, or both through controlled, sport-specific movements, has become the popular choice of pre-exercise warm-up. This type of warm-up has evolved to encompass several variations, but at its core is the principle theme that preparing…

  5. Iterated Stretching of Viscoelastic Jets

    NASA Technical Reports Server (NTRS)

    Chang, Hsueh-Chia; Demekhin, Evgeny A.; Kalaidin, Evgeny

    1999-01-01

    We examine, with asymptotic analysis and numerical simulation, the iterated stretching dynamics of FENE and Oldroyd-B jets of initial radius r(sub 0), shear viscosity nu, Weissenberg number We, retardation number S, and capillary number Ca. The usual Rayleigh instability stretches the local uniaxial extensional flow region near a minimum in jet radius into a primary filament of radius [Ca(1 - S)/ We](sup 1/2)r(sub 0) between two beads. The strain-rate within the filament remains constant while its radius (elastic stress) decreases (increases) exponentially in time with a long elastic relaxation time 3We(r(sup 2, sub 0)/nu). Instabilities convected from the bead relieve the tension at the necks during this slow elastic drainage and trigger a filament recoil. Secondary filaments then form at the necks from the resulting stretching. This iterated stretching is predicted to occur successively to generate high-generation filaments of radius r(sub n), (r(sub n)/r(sub 0)) = square root of 2[r(sub n-1)/r(sub 0)](sup 3/2) until finite-extensibility effects set in.

  6. Three Fresh Exposures, Stretched Color

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This panoramic camera image from NASA's Mars Exploration Rover Opportunity has been processed using a technique known as a decorrelation stretch to exaggerate the colors. The area in the image includes three holes created inside 'Endurance Crater' by Opportunity's rock abrasion tool between sols 143 and 148 (June 18 and June 23, 2004). Because color variations are so subtle in the pictured area, stretched images are useful for discriminating color differences that can alert scientists to compositional and textural variations. For example, without the exaggeration, no color difference would be discernable among the tailings left behind after the grinding of these holes, but in this stretched image, the tailings around 'London' (top) appear more red than those of the other holes ('Virginia,' middle, and 'Cobble Hill,' bottom). Scientists believe that is because the rock abrasion tool sliced through two 'blueberries,' or spherules (visible on the upper left and upper right sides of the circle). When the blades break up these spherules, composed of mostly gray hematite, the result is a bright red powder. In this image, you can see the rock layers that made the team want to grind holes in each identified layer. The top layer is yellowish red, the middle is yellowish green and the lower layer is green. Another advantage to viewing this stretched image is the clear detail of the distribution of the rock abrasion tool tailings (heading down-slope) and the differences in rock texture. This image was created using the 753-, 535- and 432-nanometer filters.

  7. SYMBIOTIC STAR BLOWS BUBBLES INTO SPACE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A tempestuous relationship between an unlikely pair of stars may have created an oddly shaped, gaseous nebula that resembles an hourglass nestled within an hourglass. Images taken with Earth-based telescopes have shown the larger, hourglass-shaped nebula. But this picture, taken with NASA's Hubble Space Telescope, reveals a small, bright nebula embedded in the center of the larger one (close-up of nebula in inset). Astronomers have dubbed the entire nebula the 'Southern Crab Nebula' (He2-104), because, from ground-based telescopes, it looks like the body and legs of a crab. The nebula is several light-years long. The possible creators of these shapes cannot be seen at all in this Wide Field and Planetary Camera 2 image. It's a pair of aging stars buried in the glow of the tiny, central nebula. One of them is a red giant, a bloated star that is exhausting its nuclear fuel and is shedding its outer layers in a powerful stellar wind. Its companion is a hot, white dwarf, a stellar zombie of a burned-out star. This odd duo of a red giant and a white dwarf is called a symbiotic system. The red giant is also a Mira Variable, a pulsating red giant, that is far away from its partner. It could take as much as 100 years for the two to orbit around each other. Astronomers speculate that the interaction between these two stars may have sparked episodic outbursts of material, creating the gaseous bubbles that form the nebula. They interact by playing a celestial game of 'catch': as the red giant throws off its bulk in a powerful stellar wind, the white dwarf catches some of it. As a result, an accretion disk of material forms around the white dwarf and spirals onto its hot surface. Gas continues to build up on the surface until it sparks an eruption, blowing material into space. This explosive event may have happened twice in the 'Southern Crab.' Astronomers speculate that the hourglass-shaped nebulae represent two separate outbursts that occurred several thousand years apart

  8. IDENTIFICATION OF CFC AND HCFC SUBSTITUTES FOR BLOWING POLYURETHANE FOAM INSULATION PRODUCTS

    EPA Science Inventory

    The report gives results of a cooperative effort to identiry chlorofluorocarbons and hydrochlorofluorocarbon substitutes for blowing polyurethane foam insulation products. The substantial ongoing effort is identifying third-generation blowing agets for polyurethane foams to repla...

  9. Control of Flow Structure on Non-Slender Delta Wing: Bio-inspired Edge Modifications, Passive Bleeding, and Pulsed Blowing

    NASA Astrophysics Data System (ADS)

    Yavuz, Mehmet Metin; Celik, Alper; Cetin, Cenk

    2016-11-01

    In the present study, different flow control approaches including bio-inspired edge modifications, passive bleeding, and pulsed blowing are introduced and applied for the flow over non-slender delta wing. Experiments are conducted in a low speed wind tunnel for a 45 degree swept delta wing using qualitative and quantitative measurement techniques including laser illuminated smoke visualization, particle image velocimety (PIV), and surface pressure measurements. For the bio-inspired edge modifications, the edges of the wing are modified to dolphin fluke geometry. In addition, the concept of flexion ratio, a ratio depending on the flexible length of animal propulsors such as wings, is introduced. For passive bleeding, directing the free stream air from the pressure side of the planform to the suction side of the wing is applied. For pulsed blowing, periodic air injection through the leading edge of the wing is performed in a square waveform with 25% duty cycle at different excitation frequencies and compared with the steady and no blowing cases. The results indicate that each control approach is quite effective in terms of altering the overall flow structure on the planform. However, the success level, considering the elimination of stall or delaying the vortex breakdown, depends on the parameters in each method.

  10. Seismotectonic implications of sand blows in the southern Mississippi Embayment

    USGS Publications Warehouse

    Cox, R.T.; Hill, A.A.; Larsen, D.; Holzer, T.; Forman, S.L.; Noce, T.; Gardner, C.; Morat, J.

    2007-01-01

    We explore seismically-induced sand blows from the southern Mississippi Embayment and their implications in resolving the question of near or distal epicentral source region. This was accomplished using aerial photography, field excavations, and cone penetration tests. Our analysis shows that three sand blow fields exhibit a distinct chronology of strong ground motion for the southern embayment: (1) The Ashley County, Arkansas sand blow field, near the Arkansas/Louisiana state border, experienced four Holocene sand venting episodes; (2) to the north, the Desha County field experienced at least three episodes of liquefaction; and (3) the Lincoln-Jefferson Counties field experienced at least one episode. Cone penetration tests (CPT) conducted in and between the sand blow fields suggest that the fields may not be distal liquefaction associated with New Madrid seismic zone earthquakes but rather are likely associated with strong earthquakes on local faults. This conclusion is consistent with the differences in timing of the southern embayment sand venting episodes and those in the New Madrid seismic zone. These results suggest that active tectonism and strong seismicity in intraplate North America may not be localized at isolated weak spots, but rather widespread on fault systems that are favorably oriented for slip in the contemporary stress field. ?? 2006 Elsevier B.V. All rights reserved.

  11. CR-39 track etching and blow-up method

    DOEpatents

    Hankins, Dale E.

    1987-01-01

    This invention is a method of etching tracks in CR-39 foil to obtain uniformly sized tracks. The invention comprises a step of electrochemically etching the foil at a low frequency and a "blow-up" step of electrochemically etching the foil at a high frequency.

  12. PLA fibers with antimicrobial properties developed by solution blow spinning

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The present work reports on the development and characterization of novel Poly(lactic acid) hybrid fibers with antimicrobial properties produced by solution blow spinning. This technique presents additional advantages over conventional electrospinning, such as reduced cost and higher rate of fiber p...

  13. Proteus mirabilis interkingdom swarming signals attract blow flies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flies transport specific bacteria with their larvae which provides a wider range of nutrients for those bacteria. Our hypothesis was that this symbiotic interaction may depend on interkingdom signaling. We obtained Proteus mirabilis from the salivary glands of the blow fly Lucilia sericat. This s...

  14. 67. View looking east up walkway between blowing engine house ...

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

    67. View looking east up walkway between blowing engine house at left and boilers at right showing base of stack for boilers No. 5 and 6. - Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham, Jefferson County, AL

  15. 42. NORTHEAST VIEW OF BLOW ENGINE HOUSE No. 3, WITH ...

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

    42. NORTHEAST VIEW OF BLOW ENGINE HOUSE No. 3, WITH FILTER CAKE HOSUE IN CENTER FOREGROUND, AND EVAPORATIVE WASTE WATER TREATMENT COOLING TOWER TO THE LEFT. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  16. Levitating a strip of paper by blowing over it

    NASA Astrophysics Data System (ADS)

    Lipscombe, Trevor C.; Mungan, Carl E.

    2016-11-01

    It is shown that if you blow vigorously over a curved strip of paper, it levitates into the shape of a catenary. This result quantifies a common classroom demonstration and is a pedagogically useful addition to other studies of catenaries in an intermediate classical mechanics course.

  17. Solution blow spinning of food-grade gelatin nanofibers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The primary advantage of nanofibers over larger diameter fibers is the larger surface area to volume ratio. This study evaluated solution blow spinning (SBS) processing conditions for obtaining food-grade gelatin nanofibers from mammalian and fishery by-products, such as pork skin gelatins (PGs) and...

  18. Preparation of zein fibers using solution blow spinning method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zein fibers were successfully fabricated via solution blow spinning (SBS) using acetic acid as solvent. Surface tension, viscosity and modulus of zein solutions were respectively determined by force tensiometer and rheometer. Increases of these properties were observed with an increase of concentrat...

  19. How often do normal persons sneeze and blow the nose?

    PubMed

    Hansen, Bjarne; Mygind, Niels

    2002-03-01

    Rhinitis is defined as an inflammatory disease, but in clinical practice the diagnosis is based on the occurrence of nasal symptoms. As all persons occasionally sneeze and blow the nose, it is necessary to define what is normal. In this study the daily number of sneezes and of nose blowing were recorded in diary-cards over a 14 day period by 80 hospital employees and medical students, who considered themselves not to suffer from rhinitis. The results showed that more than 95% of the normal persons sneezed and blew the nose less than 4 times a day, on average. It is concluded that it is normal to sneeze and blow the nose less than 4 times daily while a higher number can be a sign of rhinitis. It is recommended that counting of sneezes and of nose blowing is used in clinical trials in order to define the study population. Together with an objective measurement of nasal patency this can be useful in defining the effect profile of different types of treatment.

  20. Stagnation region gas film cooling: Spanwise angled injection from multiple rows of holes. [gas turbine engines

    NASA Technical Reports Server (NTRS)

    Luckey, D. W.; Lecuyer, M. R.

    1981-01-01

    The stagnation region of a cylinder in a cross flow was used in experiments conducted with both a single row and multiple rows of spanwise angled (25 deg) coolant holes for a range of the coolant blowing ratio with a freestream to wall temperature ratio approximately equal to 1.7 and R(eD) = 90,000. Data from local heat flux measurements are presented for injection from a single row located at 5 deg, 22.9 deg, 40.8 deg, 58.7 deg from stagnation using a hole spacing ratio of S/d(o) = 5 and 10. Three multiple row configurations were also investigated. Data are presented for a uniform blowing distribution and for a nonuniform blowing distribution simulating a plenum supply. The data for local Stanton Number reduction demonstrated a lack of lateral spreading by the coolant jets. Heat flux levels larger than those without film cooling were observed directly behind the coolant holes as the blowing ratio exceeded a particular value. The data were spanwise averaged to illustrate the influence of injection location, blowing ratio and hole spacing. The large values of blowing ratio for the blowing distribution simulating a plenum supply resulted in heat flux levels behind the holes in excess of the values without film cooling. An increase in freestream turbulence intensity from 4.4 to 9.5 percent had a negligible effect on the film cooling performance.

  1. Polymer network stretching during electrospinning

    NASA Astrophysics Data System (ADS)

    Greenfeld, Israel; Arinstein, Arkadii; Fezzaa, Kamel; Rafailovich, Miriam; Zussman, Eyal

    2011-03-01

    Fast X-ray phase contrast imaging is used to observe the flow of a semi-dilute polyethylene oxide solution during electrospinning. Micron-size glass particles mixed in the polymer solution allow viewing of the jet flow field, and reveal a high-gradient flow that has both longitudinal and radial components that grow rapidly along the jet. The resulting hydrodynamic forces cause substantial longitudinal stretching and transversal contraction of the polymer network within the jet, as confirmed by random walk simulation and theoretical modeling. The polymer network therefore concentrates towards the jet center, and its conformation may transform from a free state to a fully-stretched state within a short distance from the jet start. We acknowledge the financial support of the United States - Israel Bi-National Science Foundation (grant 2006061).

  2. Jaw stretch reflexes in children.

    PubMed

    Finan, Donald S; Smith, Anne

    2005-07-01

    The substantial morphological transformations that occur during human development present the nervous system with a considerable challenge in terms of motor control. Variability of skilled motor performance is a hallmark of a developing system. In adults, the jaw stretch reflex contributes to the functional stability of the jaw. We have investigated the response properties of the jaw stretch reflex in two groups of young children and a group of young adults. Response latencies increased with development, and all age groups produced stimulus-magnitude-dependent increases in reflex gain and resulting biting force. Reflex gain was largest for the older children (9-10 years), yet net increases in resulting biting force were comparable across age groups. These data and earlier experiments suggest that oral sensorimotor pathways mature throughout childhood in concert with the continued acquisition of complex motor skills.

  3. Full-coverage film cooling. I - Comparison of heat transfer data for three injection angles

    NASA Technical Reports Server (NTRS)

    Crawford, M. E.; Kays, W. M.; Moffat, R. J.

    1980-01-01

    Wind tunnel experiments were carried out at Stanford between 1971 and 1977 to study the heat transfer characteristics of full-coverage film cooled surfaces with three geometries; normal-, 30 deg slant-, and 30 deg x 45 deg compound-angled injection. A flat full-coverage section and downstream recovery section comprised the heat transfer system. The experimental objectives were to determine, for each geometry, the effects on surface heat flux of injection blowing ratio, injection temperature ratio, and upstream initial conditions. Spanwise-averaged Stanton numbers were measured for blowing ratios from 0 to 1.3, and for two values of injection temperature at each blowing ratio. The heat transfer coefficient was defined on the basis of a mainstream-to-wall temperature difference. Initial momentum and enthalpy thickness Reynolds numbers were varied from 500 to about 3000.

  4. Stator Loading Measurements Behind a Fan With Trailing Edge Blowing

    NASA Technical Reports Server (NTRS)

    Waitz, Ian A.

    2000-01-01

    The problem of aircraft noise pollution around airports has become increasingly important as those areas have become more densely populated. Currently, the removal of older noisier aircraft from operation is reducing noise levels around airports; however, with air traffic projected to increase by about 5% over the next decade the number of commercial aircraft operating in the world is expected to be about 17,700 by the year 2007. To keep noise levels around airports from increasing as a result of traffic increases, it is important to investigate new methods of noise reduction. The objective of this work is to provide a better understanding of the effects that trailing edge blowing has on stator unsteady loading. This is done by presenting flowfield and stator loading data from experiments conducted with and without trailing edge blowing.

  5. Solution blowing of submicron-scale cellulose fibers.

    PubMed

    Zhuang, Xupin; Yang, Xiaocan; Shi, Lei; Cheng, Bowen; Guan, Ketian; Kang, Weimin

    2012-10-01

    Solution blowing is an innovative process for spinning micro-/nano-fibers from polymer solutions using high-velocity gas flow as fiber forming driving force. Submicron-scale cellulose fibers were successfully solution blown by two improvement measures. First, cellulose solution was directly blown to fibers of 260-1900 nm in diameter by raising the air temperature along the spinning line which was proved to accelerate the evaporation of solvent and fiber forming. Second, coaxial solution blowing technique was established with cellulose solution and polyethylene oxide (PEO) solution used as core and shell liquids, respectively. The core-shell structures of the fibers were examined by SEM and TEM. Cellulose fibers with diameter between 160 nm and 960 nm were further obtained after removing PEO shell. X-ray diffraction studies showed that the two kinds of submicron-scale cellulose fibers are mostly amorphous.

  6. Lift augmentation via spanwise tip blowing - A numerical study

    NASA Technical Reports Server (NTRS)

    Childs, R. E.

    1986-01-01

    Numerical simulations of a low aspect ratio wing with and without a spanwise directed jet issuing from the wing tip have been performed. The results show that the tip vortex is displaced outward and upward by the blowing. This gives rise to a local lift augmentation mechanism, vortex lift caused by the vortex core being above the wing, and a global mechanism, the reduction of induced velocities due to greater apparent spin.

  7. A theoretical investigation of over-wing-blowing aerodynamics

    NASA Technical Reports Server (NTRS)

    Lan, C. E.

    1976-01-01

    A theoretical method is established for determining the aerodynamic characteristics of over-wing-blowing configurations. The method accounts for both jet entrainment and jet interaction effects because of the differences in freestream and jet dynamic pressures and Mach numbers. The predicted lift increments agree well with available data. It is shown that the lift is underpredicted with entrainment effect alone when the jet is close to the wing surface.

  8. Blow-up regimes in failure of rock specimens

    NASA Astrophysics Data System (ADS)

    Smolin, I. Yu.; Kulkov, A. S.; Makarov, P. V.; Eremin, M. O.; Bakeev, R. A.; Krasnoveykin, V. A.

    2016-11-01

    For damage evaluation, the stage of superfast catastrophic failure of a medium and its mechanical behavior in a state of self-organized criticality prior to the onset of a blow-up fracture mode is of great interest for identification of its precursors. In this work, the data of experimental and numerical investigations of mechanical behavior of a medium before its catastrophic failure and the onset of a blow-up fracture mode are presented. Rock samples and ceramic specimens are subjected to three-point bending and uniaxial compression testing. Surface velocities of the loaded specimens are registered using a laser Doppler vibrometer. The blow-up regime duration is measured to be about 10-20 ms. The specimens' mechanical behavior is numerically simulated under experimental conditions, including the regime of catastrophic fracture. The model parameters of damage accumulation are determined from a comparison with the experimental data. A number of features of the material mechanical response before the catastrophic fracture are identified, which could be treated as failure precursors.

  9. An implicit finite-difference solution to the viscous shock layer, including the effects of radiation and strong blowing

    NASA Technical Reports Server (NTRS)

    Garrett, L. B.; Smith, G. L.; Perkins, J. N.

    1972-01-01

    An implicit finite-difference scheme is developed for the fully coupled solution of the viscous, radiating stagnation-streamline equations, including strong blowing. Solutions are presented for both air injection and injection of carbon-phenolic ablation products into air at conditions near the peak radiative heating point in an earth entry trajectory from interplanetary return missions. A detailed radiative-transport code that accounts for the important radiative exchange processes for gaseous mixtures in local thermodynamic and chemical equilibrium is utilized in the study. With minimum number of assumptions for the initially unknown parameters and profile distributions, convergent solutions to the full stagnation-line equations are rapidly obtained by a method of successive approximations. Damping of selected profiles is required to aid convergence of the solutions for massive blowing. It is shown that certain finite-difference approximations to the governing differential equations stabilize and improve the solutions. Detailed comparisons are made with the numerical results of previous investigations. Results of the present study indicate lower radiative heat fluxes at the wall for carbonphenolic ablation than previously predicted.

  10. Cabazitaxel Injection

    MedlinePlus

    ... injection is used along with prednisone to treat prostate cancer (cancer of a male reproductive organ) that has ... cabazitaxel injection is usually used in men with prostate cancer. If used by pregnant women, cabazitaxel injection can ...

  11. Fondaparinux Injection

    MedlinePlus

    ... fondaparinux injection.Talk to your doctor about the risk of using fondaparinux injection. ... Fondaparinux injection is used to prevent deep vein thrombosis (DVT; a blood ... Xa inhibitors. It works by decreasing the clotting ability of the blood.

  12. Morphine Injection

    MedlinePlus

    Morphine injection is used to relieve moderate to severe pain. Morphine is in a class of medications called opiate ( ... Morphine injection comes as a solution (liquid) to inject intramuscularly (into a muscle) or intravenously (into a ...

  13. Dexamethasone Injection

    MedlinePlus

    Dexamethasone injection is used to treat severe allergic reactions. It is used in the management of certain types of ... gastrointestinal disease, and certain types of arthritis. Dexamethasone injection is also used for diagnostic testing. Dexamethasone injection ...

  14. Romidepsin Injection

    MedlinePlus

    Romidepsin injection is used to treat cutaneous T-cell lymphoma (CTCL; a group of cancers of the immune system ... one other medication given by mouth or by injection. Romidepsin injection is in a class of medications ...

  15. Ondansetron Injection

    MedlinePlus

    Zofran® Injection ... Ondansetron injection is used to prevent nausea and vomiting caused by cancer chemotherapy and surgery. Ondansetron is in a ... medications: or any of the ingredients in ondansetron injection. Ask your pharmacist for a list of the ...

  16. Active control of wing rock of a delta wing at post-stall using tangential leading edge blowing

    NASA Technical Reports Server (NTRS)

    Wong, G. S.; Rock, S. M.; Wood, N. J.; Roberts, L.

    1993-01-01

    Post-stall roll control utilizing tangential leading edge blowing is demonstrated in a wind tunnel on a delta wing model that exhibited wing rock. The dampening effect of symmetric blowing alone on wing rock is found to be effective up to a certain maximum amount of blowing. A moderate amount of symmetric blowing was shown to be effective in linearizing the asymmetric blowing static rolling moment responses.

  17. Spatial and temporal variations of blowing dust events in the Taklimakan Desert

    NASA Astrophysics Data System (ADS)

    Yang, Xinghua; Shen, Shuanghe; Yang, Fan; He, Qing; Ali, Mamtimin; Huo, Wen; Liu, Xinchun

    2016-08-01

    The Taklimakan Desert is the source of most blowing dust events in China. However, previous studies of sandstorms in this region have not included data from the inner desert because of the difficulty in making observations in this area. In this study, the spatial and temporal variations of blowing dust events, including sandstorms and blowing sand, and its relations with climatic parameters in the Taklimakan Desert were analyzed using data from ten desert-edge meteorological stations during 1961 to 2010 and two inner-desert meteorological stations during 1988 to 1990, 1996 to 2010, and 1992 to 2010. The results identified two regions (Pishan-Hotan-Minfeng and Xiaotang-Tazhong) where blowing dust events occur on average more than 80 days per year. The regions with the highest occurrence of sandstorms, blowing sand, and blowing dust events were different, with sandstorms centered in the north of the desert (Xiaotang, 46.9 days), whereas the central location for blowing sand (Pishan, 86.4 days) and blowing dust events (Minfeng, 113.5 days) activity was located at the southwestern and southern edges of the desert, respectively. The occurrence of sandstorms generally decreased from 1961 to 2010, while the occurrence of blowing sand increased from 1961 to 1979 and then generally decreased. The temporal variation of blowing dust events was mainly affected by the occurrence of strong wind and daily temperature, with average correlation coefficients of 0.46 and -0.41 for these variables across the whole desert.

  18. Structure development of polyamides (=nylons) in film extrusion and stretching processes

    NASA Astrophysics Data System (ADS)

    Rhee, Sangkeun

    2000-08-01

    A fundamental investigation of film formation characteristics and structure development of polyamide 6 (PA6), polyamide 612 (PA612), polyamide 11 (PA11) and polyamide 12 (PA12) in four different types of film formation processes (single bubble, double bubble, cast and biaxial stretching) was carried out. We made a careful study of film processing stability. The extrusion and cooling conditions were of special concern for single bubble films and extrusion cast films. To make first bubble and extrusion cast films which were suitable for additional stretching processes was another concern. In the sense of processibility and structure development, the stretching temperature and second air ring temperature were found to be important for uni- and biaxial stretching processes of extrusion cast films and for double bubble film blowing process, respectively. The crystallization rate of polyamides, which is related to the amide group concentration in their monomer units, provided a determining factor for double bubble inflation. As the distance between amide groups increases, the crystallization rate increases and film becomes increasingly unsuitable for double bubble processing. The aging behaviors of first bubble and unstretched extrusion cast films were studied using DSC heating scans. Changes of crystallinity, glass transition temperature and cold crystallization temperature were monitored during aging at room conditions. The existence of polymorphism in the crystalline structure of polyamide films was investigated with IR spectroscopy, WAXS flat film patterns, 2θ WAXS scanning and pole figure data. Effects of film formation conditions and of annealing on the crystal polymorphism were investigated. Molecular orientation was determined by birefringence measurements and crystalline biaxial orientation factor measurement (using pole figure data). The unstretched extrusion cast films were almost isotropic. Single bubble film ranged from isotropic to significant level of

  19. Role of fluid density in shaping eruption currents driven by frontal particle blow-out

    NASA Astrophysics Data System (ADS)

    Carroll, C. S.; Turnbull, B.; Louge, M. Y.

    2012-06-01

    We study the role of suspension density in eruption currents, a regime of gravity-driven flow that is sustained by massive, localized blow-out of particles acting as a steady source of heavier fluid injected into a uniform flow at high Reynolds number. Inspired by the potential flow solution of Saffman and Yuen ["Finite-amplitude interfacial waves in the presence of a current," J. Fluid Mech. 123, 459-476 (1982), 10.1017/S0022112082003152], we show that the relative density difference between the two fluids swells the size of the current's head without changing its shape, while inducing a velocity jump at the interface. We test this inviscid theory against inviscid and large-eddy-simulations. We also conduct experiments in a water flume, where a line source of fluorescent brines of various densities is injected in a cross-stream and visualized with a narrow sheet of light. Simulations and experiments reveal that, with isotropic velocity distribution on a finite source, eruption currents expand further and develop interface oscillations, but the inviscid theory still captures relative swelling induced by density. We compare predictions to the static pressure data of McElwaine and Turnbull ["Air pressure data from the Vallee de la Sionne avalanches of 2004," J. Geophys. Res. 110, F03010, doi:, 10.1029/2004JF000237 (2005)] in powder snow avalanches.

  20. Decorrelation Stretch Near Cerberus Fossae

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released July 25, 2004 On this image you can see two infrared frames of the same area on Mars. One of the images (in black and white) represents a single wavelength or band of the THEMIS IR instrument, while the other image (in false color) represents 3 different bands. The image with the various colors was created with a technique called Decorrelation Stretch (DCS). In this technique individual bands of the THEMIS IR instrument are stretched to better show compositional variations throughout the whole range. After the bands are stretched they are overlayed on one another and colors are assigned to each band. This makes up the colors in the image.

    As you can see, there is a difference in what is noticable in the single band IR image versus the false-colored one. On the color image the pink/magenta colors usually represent basaltic content, cyan often indicates the presence of water ice clouds, while green can represent dust.

    The bright purple and pink colors associated with the valley are due to basalt. There may be a thin veneer of dust present in the region (it was a dark colored region during the Viking mission in the 1970's) through which the basaltic material pokes out along the edges of the valley and the nearby knobby terrain.

    Image information: IR instrument. Latitude 10.7, Longitude 163 East (197 West). 100 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA

  1. Expression of polyalanine stretches induces mitochondrial dysfunction.

    PubMed

    Toriumi, Kazuya; Oma, Yoko; Kino, Yoshihiro; Futai, Eugene; Sasagawa, Noboru; Ishiura, Shoichi

    2008-05-15

    In recent years, several novel types of disorders have been characterized, including what have been termed polyalanine diseases, in which patients have expanded triplet repeats in specific genes, resulting in the translation of aberrantly elongated polyalanine stretches. In this study, we showed that yellow fluorescent protein (YFP)-fused elongated polyalanine stretches localized exclusively to the cytoplasm and formed aggregates. Additionally, the polyalanine stretches themselves were toxic. We sought to identify proteins that bound directly to the polyalanine stretches, as factors that might be involved in triggering cell death. Many mitochondrial proteins were identified as polyalanine-binding proteins. We showed that one of the identified proteins, succinate dehydrogenase subunit A, was decreased in the mitochondria of cells expressing polyalanine stretches; as a result, succinate oxidative activity was decreased. Furthermore, the polyalanine stretches also associated directly with mitochondria. This suggests that polya-lanine stretches might directly induce cell death. Additionally, the mitochondrial membrane potential was reduced in cells expressing polyalanine stretches. We propose a novel mechanism by which polyalanine stretches may cause cytotoxicity through mitochondrial dysfunction. This may be a common mechanism underlying the pathogenesis of all polyalanine diseases.

  2. Cell reorientation under cyclic stretching

    PubMed Central

    Livne, Ariel; Bouchbinder, Eran; Geiger, Benjamin

    2014-01-01

    Mechanical cues from the extracellular microenvironment play a central role in regulating the structure, function and fate of living cells. Nevertheless, the precise nature of the mechanisms and processes underlying this crucial cellular mechanosensitivity remains a fundamental open problem. Here we provide a novel framework for addressing cellular sensitivity and response to external forces by experimentally and theoretically studying one of its most striking manifestations – cell reorientation to a uniform angle in response to cyclic stretching of the underlying substrate. We first show that existing approaches are incompatible with our extensive measurements of cell reorientation. We then propose a fundamentally new theory that shows that dissipative relaxation of the cell’s passively-stored, two-dimensional, elastic energy to its minimum actively drives the reorientation process. Our theory is in excellent quantitative agreement with the complete temporal reorientation dynamics of individual cells, measured over a wide range of experimental conditions, thus elucidating a basic aspect of mechanosensitivity. PMID:24875391

  3. Cell reorientation under cyclic stretching

    NASA Astrophysics Data System (ADS)

    Livne, Ariel; Bouchbinder, Eran; Geiger, Benjamin

    2014-05-01

    Mechanical cues from the extracellular microenvironment play a central role in regulating the structure, function and fate of living cells. Nevertheless, the precise nature of the mechanisms and processes underlying this crucial cellular mechanosensitivity remains a fundamental open problem. Here we provide a novel framework for addressing cellular sensitivity and response to external forces by experimentally and theoretically studying one of its most striking manifestations—cell reorientation to a uniform angle in response to cyclic stretching of the underlying substrate. We first show that existing approaches are incompatible with our extensive measurements of cell reorientation. We then propose a fundamentally new theory that shows that dissipative relaxation of the cell’s passively-stored, two-dimensional, elastic energy to its minimum actively drives the reorientation process. Our theory is in excellent quantitative agreement with the complete temporal reorientation dynamics of individual cells measured over a wide range of experimental conditions, thus elucidating a basic aspect of mechanosensitivity.

  4. Ibandronate Injection

    MedlinePlus

    Boniva® Injection ... Ibandronate injection is used to treat osteoporosis (a condition in which the bones become thin and weak and break ... Ibandronate injection comes as a solution (liquid) to be injected into a vein by a doctor or nurse in ...

  5. Leuprolide Injection

    MedlinePlus

    Leuprolide injection comes as a long-acting suspension (Lupron) that is injected intramuscularly (into a muscle) by a doctor or nurse in a medical ... Depot-4 month, Lupron Depot-6 Month). Leuprolide injection also comes as a long-acting suspension (Eligard) that is injected subcutaneously (just under ...

  6. Sexual Harassment Reporting and Whistle-Blowing: A Proposed Model of Predictors and Outcomes

    DTIC Science & Technology

    2002-01-01

    To) 19/Feb/2002 MAJOR REPORT 1 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER SEXUAL HARASSMENT REPORTING AND WHISTLE BLOWING: A PROPSED MODEL OF...TELEPHONE NUMBER (Include area code) Standard Form 298 (Rev. 8/98) Prescribed by ANSI Std. Z39.18 Sexual Harassment Reporting and Whistle-blowing: A...Funding for this study was provided by the Coleman Chair of the Kelley School of Business. Sexual Harassment Reporting and Whistle-blowing: A

  7. Blow-up properties in the parabolic problems with anisotropic nonstandard growth conditions

    NASA Astrophysics Data System (ADS)

    Liu, Bingchen; Yang, Jie

    2016-03-01

    In this paper, we study the parabolic problems with anisotropic nonstandard growth nonlinearities. We first give the existence and uniqueness of weak solutions in variable Sobolev spaces. Second, we use the energy methods to show the existence of blow-up solutions with negative or positive initial energy, respectively. Both the variable exponents and the coefficients make important roles in Fujita blow-up phenomena. Moreover, asymptotic properties of the blow-up solutions are determined.

  8. Kinematics analyses related to stretch-shortening cycle during soccer instep kicking after different acute stretching.

    PubMed

    Amiri-Khorasani, Mohammadtaghi; Mohammadkazemi, Reza; Sarafrazi, Soodeh; Riyahi-Malayeri, Shahin; Sotoodeh, Vahid

    2012-11-01

    The purpose of this study was to examine the effects of static and dynamic stretching within a preexercise warm-up on angular velocity of knee joint, deepest knee flexion (DKF), and duration of eccentric and concentric contractions, which are relative to the stretch-shortening cycle (SSC) during instep kicking in professional soccer players. The kicking motions of dominant legs were captured from 18 Olympic professional male soccer players (height: 180.38 ± 7.34 cm; weight: 69.77 ± 9.73 kg; age: 19.22 ± 1.83 years) using 4 digital video cameras at 50 Hz. There was a significant difference in the DKF after the dynamic stretching (-3.22 ± 3.10°) vs. static stretching (-0.18 ± 3.19°) relative to the no-stretching method with p < 0.001. Moreover, there was significant difference in eccentric duration after the dynamic stretching (0.006 ± 0.01 seconds) vs. static stretching (-0.003 ± 0.01 seconds) relative to the no-stretching method with p < 0.015. There was a significant difference in the concentric duration after the dynamic stretching (-0.007 ± 0.01 seconds) vs. static stretching (0.002 ± 0.01 seconds) relative to the no-stretching method with p < 0.001. There was also a significant difference in knee angular velocity after the dynamic stretching (4.08 ± 3.81 rad·s) vs. static stretching (-5.34 ± 4.40 rad·s) relative to the no-stretching method with p < 0.001. We concluded that dynamic stretching during warm-ups, as compared with static stretching, is probably the most effective way as preparation for the kinematics characteristics of soccer instep kick, which are relative to the SSC.

  9. The development of three-dimensional adjoint method for flow control with blowing in convergent-divergent nozzle flows

    NASA Astrophysics Data System (ADS)

    Sikarwar, Nidhi

    The noise produced by the low bypass ratio turbofan engines used to power fighter aircraft is a problem for communities near military bases and for personnel working in close proximity to the aircraft. For example, carrier deck personnel are subject to noise exposure that can result in Noise-Induced Hearing Loss which in-turn results in over a billion dollars of disability payments by the Veterans Administration. Several methods have been proposed to reduce the jet noise at the source. These methods include microjet injection of air or water downstream of the jet exit, chevrons, and corrugated nozzle inserts. The last method involves the insertion of corrugated seals into the diverging section of a military-style convergent-divergent jet nozzle (to replace the existing seals). This has been shown to reduce both the broadband shock-associated noise as well as the mixing noise in the peak noise radiation direction. However, the original inserts were designed to be effective for a take-off condition where the jet is over-expanded. The nozzle performance would be expected to degrade at other conditions, such as in cruise at altitude. A new method has been proposed to achieve the same effects as corrugated seals, but using fluidic inserts. This involves injection of air, at relatively low pressures and total mass flow rates, into the diverging section of the nozzle. These fluidic inserts" deflect the flow in the same way as the mechanical inserts. The fluidic inserts represent an active control method, since the injectors can be modified or turned off depending on the jet operating conditions. Noise reductions in the peak noise direction of 5 to 6 dB have been achieved and broadband shock-associated noise is effectively suppressed. There are multiple parameters to be considered in the design of the fluidic inserts. This includes the number and location of the injectors and the pressures and mass flow rates to be used. These could be optimized on an ad hoc basis with

  10. A One-Dimensional Global-Scaling Erosive Burning Model Informed by Blowing Wall Turbulence

    NASA Technical Reports Server (NTRS)

    Kibbey, Timothy P.

    2014-01-01

    A derivation of turbulent flow parameters, combined with data from erosive burning test motors and blowing wall tests results in erosive burning model candidates useful in one-dimensional internal ballistics analysis capable of scaling across wide ranges of motor size. The real-time burn rate data comes from three test campaigns of subscale segmented solid rocket motors tested at two facilities. The flow theory admits the important effect of the blowing wall on the turbulent friction coefficient by using blowing wall data to determine the blowing wall friction coefficient. The erosive burning behavior of full-scale motors is now predicted more closely than with other recent models.

  11. Controlled vortical flow on delta wings through unsteady leading edge blowing

    NASA Technical Reports Server (NTRS)

    Lee, K. T.; Roberts, Leonard

    1990-01-01

    The vortical flow over a delta wing contributes an important part of the lift - the so called nonlinear lift. Controlling this vortical flow with its favorable influence would enhance aircraft maneuverability at high angle of attack. Several previous studies have shown that control of the vortical flow field is possible through the use of blowing jets. The present experimental research studies vortical flow control by applying a new blowing scheme to the rounded leading edge of a delta wing; this blowing scheme is called Tangential Leading Edge Blowing (TLEB). Vortical flow response both to steady blowing and to unsteady blowing is investigated. It is found that TLEB can redevelop stable, strong vortices even in the post-stall angle of attack regime. Analysis of the steady data shows that the effect of leading edge blowing can be interpreted as an effective change in angle of attack. The examination of the fundamental time scales for vortical flow re-organization after the application of blowing for different initial states of the flow field is studied. Different time scales for flow re-organization are shown to depend upon the effective angle of attack. A faster response time can be achieved at angles of attack beyond stall by a suitable choice of the initial blowing momentum strength. Consequently, TLEB shows the potential of controlling the vortical flow over a wide range of angles of attack; i.e., in both for pre-stall and post-stall conditions.

  12. Modeling of Droplet Generation in a Top Blowing Steelmaking Process

    NASA Astrophysics Data System (ADS)

    Rout, Bapin Kumar; Brooks, Geoff; Subagyo; Rhamdhani, M. Akbar; Li, Zushu

    2016-12-01

    Quantification of metal droplets ejected due to impinging gas jet on the surface of liquid metal is an important parameter for the understanding and for the modeling of the refining kinetics of reactions in slag-metal emulsion zone. In the present work, a numerical study has been carried out to critically examine the applicability of droplet generation rate correlation previously proposed by Subagyo et al. on the basis of dimensionless blowing number ( N B). The blowing number was re-evaluated at the impingement point of jet with taking into account the temperature effect of change in density and velocity of the gas jet. The result obtained from the work shows that the modified blowing number N B,T at the furnace temperature of 1873 K (1600 °C) is approximately double in magnitude compared to N B calculated by Subagyo and co-workers. When N B,T has been employed to the Subagyo's empirical correlation for droplet generation, a wide mismatch is observed between the experimental data obtained from cold model and hot model experiments. The reason for this large deviation has been investigated in the current study, and a theoretical approach to estimate the droplet generation rate has been proposed. The suitability of the proposed model has been tested by numerically calculating the amount of metals in slag. The study shows that the weight of metals in emulsion falls in the range of 0 to 21 wt pct of hot metal weight when droplet generation rate has been calculated at ambient furnace temperature of 1873 K (1600 °C).

  13. Ground effects on USB configurations. [Upper Surface Blowing

    NASA Technical Reports Server (NTRS)

    Lan, C. E.

    1979-01-01

    Recent investigations of ground effects on aerodynamic characteristics have been stimulated by the interest in powered-lift STOL airplanes. The ground effects on upper-surface-blowing (USB) configurations may involve change in both the circulation forces and the jet reaction forces. In this note, a theoretical method is proposed for predicting these effects. It is shown that the predicted results agree well with available experimental data. In particular, the wing-alone method is shown to be incapable of predicting the ground effects of USB configurations.

  14. Spatial simulation of instability control by periodic suction blowing

    NASA Technical Reports Server (NTRS)

    Danabasoglu, G.; Biringen, S.; Streett, C. L.

    1991-01-01

    The applicability of active control by periodic suction blowing in spatially evolving plane Poiseuille flow is investigated by the direct simulation of the three-dimensional, incompressible Navier-Stokes equations. The results reveal that significant reductions in perturbation amplitudes can be obtained by a proper choice of the control wave amplitude and phase. The upstream influence of the control wave is shown to be confined to a region in the vicinity of the control slot with no apparent effect on the flow development.

  15. Two blowing concepts for roll and lateral control of aircraft

    NASA Technical Reports Server (NTRS)

    Tavella, D. A.; Wood, N. J.; Lee, C. S.; Roberts, L.

    1986-01-01

    Two schemes to modulate aerodynamic forces for roll and lateral control of aircraft have been investigated. The first scheme, called the lateral blowing concept, consists of thin jets of air exiting spanwise, or at small angle with the spanwise direction, from slots at the tips of straight wings. For this scheme, in addition to experimental measurements, a theory was developed showing the analytical relationship between aerodynamic forces and jet and wing parameters. Experimental results confirmed the theoretically derived scaling laws. The second scheme, which was studied experimentally, is called the jet spoiler concept and consists of thin jets exiting normally to the wing surface from slots aligned with the spanwise direction.

  16. Entrainment of leech swimming activity by the ventral stretch receptor.

    PubMed

    Yu, Xintian; Friesen, W Otto

    2004-11-01

    Rhythmic animal movements originate in CNS oscillator circuits; however, sensory inputs play an important role in shaping motor output. Our recent studies demonstrated that leeches with severed nerve cords swim with excellent coordination between the two ends, indicating that sensory inputs are sufficient for maintaining intersegmental coordination. In this study, we examined the neuronal substrates that underlie intersegmental coordination via sensory mechanisms. Among the identified sensory neurons in the leech, we found the ventral stretch receptor (VSR) to be the best candidate for our study because of its sensitivity to tension in longitudinal muscle. Our experiments demonstrate that (1) the membrane potential of the VSR is depolarized during swimming and oscillates with an amplitude of 1.5-5.0 mV, (2) rhythmic currents injected into the VSR can entrain ongoing swimming over a large frequency range (0.9-1.8 Hz), and (3) large current pulses injected into the VSR shift the phase of the swimming rhythm. These results suggest that VSRs play an important role in generating and modulating the swim rhythm. We propose that coordinated swimming in leech preparations with severed nerve cords results from mutual entrainment between the two ends of the leech mediated by stretch receptors.

  17. Mars Under the Microscope (stretched)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This magnified look at the martian soil near the Mars Exploration Rover Opportunity's landing site, Meridiani Planum, shows coarse grains sprinkled over a fine layer of sand. The image was captured on the 10th day, or sol, of the rover's mission by its microscopic imager, located on the instrument deployment device, or 'arm.' Scientists are intrigued by the spherical rocks, which can be formed by a variety of geologic processes, including cooling of molten lava droplets and accretion of concentric layers of material around a particle or 'seed.'

    The examined patch of soil is 3 centimeters (1.2 inches) across. The circular grain in the lower left corner is approximately 3 millimeters (.12 inches) across, or about the size of a sunflower seed.

    This stretched color composite was obtained by merging images acquired with the orange-tinted dust cover open and closed. The varying hints of orange suggest differences in mineral composition. The blue tint at the lower right corner is a tag used by scientists to indicate that the dust cover is closed.

  18. Capillary stretching of elastic fibers

    NASA Astrophysics Data System (ADS)

    Protiere, Suzie; Stone, Howard A.; Duprat, Camille

    2014-11-01

    Fibrous media consisting of constrained flexible fibers can be found in many engineered systems (membranes in filters, woven textile, matted paper). When such materials interact with a liquid, the presence of liquid/air interfaces induces capillary forces that deform the fibers. To model this interaction we study the behaviour of a finite volume of liquid deposited on two parallel flexible fibers clamped at both ends. A tension along the fibers is imposed and may be varied. We show that the system undergoes various morphological changes as the interfiber distance, the elasticity and the tension of the fibers are varied. For a certain range of parameters, the liquid spreads along the fibers and pulls them together, leading to the ``zipping'' of the fibers. This capillary adhesion can then be enhanced or reduced by changing the tension within the fibers. We will show that balancing stretching and capillary forces allows the prediction of this transition as well as the conditions for which detachment of the fibers occurs. These results may be used to prevent the clogging of fibrous membranes or to optimize the capture of liquids.

  19. Numerical Analysis of Film Cooling at High Blowing Ratio

    NASA Technical Reports Server (NTRS)

    El-Gabry, Lamyaa; Heidmann, James; Ameri, Ali

    2009-01-01

    Computational Fluid Dynamics is used in the analysis of a film cooling jet in crossflow. Predictions of film effectiveness are compared with experimental results for a circular jet at blowing ratios ranging from 0.5 to 2.0. Film effectiveness is a surface quantity which alone is insufficient in understanding the source and finding a remedy for shortcomings of the numerical model. Therefore, in addition, comparisons are made to flow field measurements of temperature along the jet centerline. These comparisons show that the CFD model is accurately predicting the extent and trajectory of the film cooling jet; however, there is a lack of agreement in the near-wall region downstream of the film hole. The effects of main stream turbulence conditions, boundary layer thickness, turbulence modeling, and numerical artificial dissipation are evaluated and found to have an insufficient impact in the wake region of separated films (i.e. cannot account for the discrepancy between measured and predicted centerline fluid temperatures). Analyses of low and moderate blowing ratio cases are carried out and results are in good agreement with data.

  20. Gas Blowing: Mass Transfer in Gas and Melt

    NASA Astrophysics Data System (ADS)

    Sortland, Øyvind Sunde; Tangstad, Merete

    2014-09-01

    Metallurgical routes for solar grade silicon production are being developed as alternatives to chemical processes for their potential to achieve cost reductions, increased production volume, and reduced environmental and safety concerns. An important challenge in the development of metallurgical routes relates to the higher impurity concentrations in the silicon product, particularly for boron and other elements that are not efficiently segregated in solidification techniques. The reactive gas refining process is studied for its potential to remove boron below the solar grade silicon target concentration in a single step by blowing steam and hydrogen gas jets onto the melt surface. Boron in a silicon melt is extracted to HBO gas in parallel to active oxidation of silicon. The literature is not unified regarding the rate determining step in this process. Relevant theories and equations for gas blowing in induction furnaces are combined and used to explain mass transfer in experiments. Mass transfer in the melt and gas is investigated by comparing resistance and induction heating of the melt, and varying gas flow rate, crucible diameter, diameter of the gas lance, and the position of the gas lance above the melt surface. The rate of boron removal is found to increase with increasing gas flow rate and crucible diameter. A relatively high fraction of the reactive gas is utilized in the process, and supply of steam in the bulk gas is the only identified rate determining step.

  1. 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.

  2. Tampa General Hospital "blows the whistle on violence".

    PubMed

    1995-01-01

    At Tampa General Hospital, the professionals in the marketing and media relations department know how to stage a press conference and to get the attention of the media. It goes to the adage when you're buying real estate: location, location, location. Once the journalists were assembled, Tampa General launched its campaign to fight street violence: "Blow the Whistle on Violence." Their timing was aided by the release of the FBI's annual Preliminary Crime Report citing Tampa as the second most dangerous city in which to live. Tampa General's news media specialist Stacey Winn reported that "the day went together just like a puzzle with all the pieces coming together." Those pieces and more are detailed in this issue's cover story on community involvement. Street crime and violence are not unique to Tampa, of course. But with so many victims ending up in Tampa General's emergency room, Winn noted that physicians and nurses felt personally responsible for contributing toward the prevention of cases ending up there. One important element in the hospital's press conference was an appearance by one of the victims of the violence they're striving to prevent. Her appearance and statement to the assembled media representatives significantly enhanced the presentation. "Blow the Whistle on Violence" was a low-cost program with a high return. The potential benefits are enormous.

  3. Resistance blow-up effect in micro-circuit engineering

    NASA Astrophysics Data System (ADS)

    Tan, Michael L. P.; Saxena, Tanuj; Arora, Vijay K.

    2010-12-01

    The nonlinearity in the I- V characteristics of a scaled-down micro/nano-scale resistive channel is shown to elevate the DC and signal resistance as current approaches its saturation value. The deviation from traditional circuit engineering takes place when the applied voltage is increased beyond the critical voltage V c = ( V t/ ℓ) L, where V t is the thermal voltage, ℓ is the ohmic mean free path, and L is the length of the conducting channel. This resistance blow-up is more pronounced for a smaller-length resistor in a micro-circuit of two resistors with same ohmic value. The power consumed P = VI not only is lower but also is a linear function of voltage V as compared to the quadratic rise with V in the ohmic regime. The resistance blow-up effect also gives enhanced RC time constant for transients when a digital signal switches from low to high or vice versa. These results are of immense value to circuit designers and those doing device characterization to extract parasitic and transport parameters.

  4. Golimumab Injection

    MedlinePlus

    ... body and causes pain, swelling, and damage) including: rheumatoid arthritis (condition in which the body attacks its own ... doctor.If golimumab injection is used to treat rheumatoid arthritis, it may also be injected intravenously (into a ...

  5. Adalimumab Injection

    MedlinePlus

    ... causes pain, swelling, and damage) including the following: rheumatoid arthritis (a condition in which the body attacks its ... If you are using adalimumab injection to treat rheumatoid arthritis, your doctor may tell you to inject the ...

  6. Aripiprazole Injection

    MedlinePlus

    ... aripiprazole injection and aripiprazole extended-release injection developed gambling problems or other intense urges or behaviors that ... even if you do not realize that your gambling or any other intense urges or unusual behaviors ...

  7. Teduglutide Injection

    MedlinePlus

    ... mix and inject it.Teduglutide comes as a kit containing vials of teduglutide powder for injection, prefilled syringes containing diluent (liquid to be mixed with teduglutide powder), needles to attach to the diluent syringe, dosing syringes ...

  8. Degarelix Injection

    MedlinePlus

    Degarelix injection is used to treat advanced prostate cancer (cancer that begins in the prostate [a male reproductive gland]). Degarelix injection is in a class of medications called gonadotropin-releasing hormone (GnRH) ...

  9. Cyclosporine Injection

    MedlinePlus

    ... injection is used with other medications to prevent transplant rejection (attack of the transplanted organ by the ... people who have received kidney, liver, and heart transplants. Cyclosporine injection should only be used to treat ...

  10. Colistimethate Injection

    MedlinePlus

    ... is used to treat certain infections caused by bacteria. Colistimethate injection is in a class of medications called antibiotics. It works by killing bacteria.Antibiotics such as colistimethate injection will not work ...

  11. Chloramphenicol Injection

    MedlinePlus

    ... treat certain types of serious infections caused by bacteria when other antibiotics cannot be used. Chloramphenicol injection ... antibiotics. It works by stopping the growth of bacteria..Antibiotics such as chloramphenicol injection will not work ...

  12. Estrogen Injection

    MedlinePlus

    ... forms of estrogen injection are used to treat hot flushes (hot flashes; sudden strong feelings of heat and sweating) ... If you are using estrogen injection to treat hot flushes, your symptoms should improve within 1 to ...

  13. Medroxyprogesterone Injection

    MedlinePlus

    ... Medroxyprogesterone injection is a very effective method of birth control but does not prevent the spread of human ... you have been using a different method of birth control and are switching to medroxyprogesterone injection, your doctor ...

  14. Etanercept Injection

    MedlinePlus

    ... areas causing pain and joint damage), chronic plaque psoriasis (a skin disease in which red, scaly patches ... etanercept injection is used to treat chronic plaque psoriasis, it may be injected twice a week during ...

  15. Levoleucovorin Injection

    MedlinePlus

    Levoleucovorin injection is used to prevent harmful effects of methotrexate (Rheumatrex, Trexall) when methotrexate is used to to treat certain types of cancer. Levoleucovorin injection is also used to treat people ...

  16. Leucovorin Injection

    MedlinePlus

    Leucovorin injection is used to prevent harmful effects of methotrexate (Rheumatrex, Trexall; cancer chemotherapy medication) when methotrexate is used to to treat certain types of cancer. Leucovorin injection is used to ...

  17. Teniposide Injection

    MedlinePlus

    ... in men. You should not become pregnant or breast-feed while you are receiving teniposide injection. If you or your partner become pregnant while receiving teniposide injection, call your doctor. Teniposide may harm the fetus.

  18. Ipilimumab Injection

    MedlinePlus

    ... are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while receiving ipilimumab injection, call your doctor. Ipilimumab injection may cause your baby to be born too early or to die before birth.

  19. Pralatrexate Injection

    MedlinePlus

    Pralatrexate injection is used to treat peripheral T-cell lymphoma (PTCL; a form of cancer that begins in a ... come back after treatment with other medications. Pralatrexate injection has not been shown to help people who ...

  20. Cyanocobalamin Injection

    MedlinePlus

    Cyanocobalamin injection is used to treat and prevent a lack of vitamin B12 that may be caused by any ... organs) and permanent damage to the nerves. Cyanocobalamin injection also may be given as a test to ...

  1. Paclitaxel Injection

    MedlinePlus

    Paclitaxel injection manufactured with human albumin is used to treat breast cancer that has not improved or that has come back after treatment with other medications. Paclitaxel injection manufactured with polyoxyethylated castor oil is used to ...

  2. Diphenhydramine Injection

    MedlinePlus

    Diphenhydramine injection is used to treat allergic reactions, especially for people who are unable to take diphenhydramine by mouth. ... is used also to treat motion sickness. Diphenhydramine injection is also used alone or along with other ...

  3. Peramivir Injection

    MedlinePlus

    Peramivir injection is used to treat some types of influenza infection ('flu') in people who have had symptoms of ... flu for no longer than 2 days. Peramivir injection is in a class of medications called neuraminidase ...

  4. Cefotetan Injection

    MedlinePlus

    Cefotetan injection is used to treat infections of the lungs, skin, bones, joints, stomach area, blood, female reproductive organs, and urinary tract. Cefotetan injection is also used before surgery to prevent infections. ...

  5. Mipomersen Injection

    MedlinePlus

    Mipomersen injection is used to decrease levels of cholesterol and other fatty substances in the blood in people who ... that removes LDL from the blood), but mipomersen injection should not be used along with this treatment. ...

  6. Romiplostim Injection

    MedlinePlus

    Romiplostim injection is used to increase the number of platelets (cells that help the blood to clot) in order ... low number of platelets in the blood). Romiplostim injection should only be used in people who cannot ...

  7. Hydrocortisone Injection

    MedlinePlus

    Hydrocortisone injection is used to treat symptoms of low corticosteroid levels (lack of certain substances that are usually produced ... also used to treat severe allergic reactions. Hydrocortisone injection is used in the management of multiple sclerosis ( ...

  8. Palivizumab Injection

    MedlinePlus

    Palivizumab injection is used to help prevent respiratory syncytial virus (RSV; common virus that can cause serious lung infections) ... or have certain heart or lung diseases. Palivizumab injection is not used to treat the symptoms of ...

  9. Naltrexone Injection

    MedlinePlus

    Naltrexone injection is used along with counseling and social support to help people who have stopped drinking large amounts of alcohol to avoid drinking again. Naltrexone injection is also used along with counseling and social ...

  10. Tesamorelin Injection

    MedlinePlus

    Tesamorelin injection is used to decrease the amount of extra fat in the stomach area in adults with human ... fat in certain areas of the body). Tesamorelin injection is not used to help with weight loss. ...

  11. Testosterone Injection

    MedlinePlus

    ... and testosterone pellet (Testopel) are forms of testosterone injection used to treat symptoms of low testosterone in ... are low before you begin to use testosterone injection. Testosterone enanthate (Delatestryl) and testosterone pellet (Testopel) are ...

  12. Tigecycline Injection

    MedlinePlus

    Tigecycline injection used to treat certain serious infections including community acquired pneumonia (a lung infection that developed in a ... area between the chest and the waist). Tigecycline injection should not be used to treat pneumonia that ...

  13. Eculizumab Injection

    MedlinePlus

    Eculizumab injection is used to treat paroxysmal nocturnal hemoglobinuria (PNH: a type of anemia in which too many red ... oxygen to all parts of the body). Eculizumab injection is also used to treat atypical hemolytic uremic ...

  14. Pembrolizumab Injection

    MedlinePlus

    Pembrolizumab injection is used to treat melanoma (a type of skin cancer) that cannot be treated with surgery or ... spread to other parts of the body. Pembrolizumab injection is also used to treat a certain type ...

  15. Methylprednisolone Injection

    MedlinePlus

    ... allergic reactions. Methylprednisolone injection is used in the management of multiple sclerosis (a disease in which the ... laboratory test, tell your doctor and the laboratory personnel that you are using methylprednisolone injection.If you ...

  16. Obinutuzumab Injection

    MedlinePlus

    Obinutuzumab injection is used with chlorambucil (Leukeran) to treat chronic lymphocytic leukemia (CLL; a type of cancer of the white blood cells). Obinutuzumab injection is in a class of medications called ...

  17. Characterization of impurity confinement on Alcator C-Mod using a multi-pulse laser blow-off system

    NASA Astrophysics Data System (ADS)

    Howard, N. T.; Greenwald, M.; Rice, J. E.

    2011-03-01

    A new laser blow-off system for use in impurity transport studies on Alcator C-Mod was developed and installed for the 2009 run campaign. Its design included capabilities for multiple impurity injections during a single plasma pulse and remote manipulation of the ablated spot size. The system uses a 0.68 J, Nd:YAG laser operating at up to 10 Hz coupled with the fast beam steering via a 2D piezoelectric mirror mount able to move spot locations in the 100 ms between laser pulses and a remote controllable optical train that allow ablated spot sizes to vary from ˜0.5 to 7 mm. The ability to ablate a wide range in target Z along with Alcator C-Mod's extensive diagnostic capabilities (soft x-ray, vacuum ultraviolet (VUV), charge exchange spectroscopy, etc.) allows for detailed studies of the impurity transport dependencies and mechanisms. This system has demonstrated the achievement of all its design goals including the ability for non-perturbative operation allowing for insight into underlying impurity transport processes. A detailed overview of the laser blow-off system and initial results of operation are presented. This includes an investigation into the characterization of impurity confinement in the I-mode confinement regime recently investigated on C-Mod.

  18. Characterization of impurity confinement on Alcator C-Mod using a multi-pulse laser blow-off system.

    PubMed

    Howard, N T; Greenwald, M; Rice, J E

    2011-03-01

    A new laser blow-off system for use in impurity transport studies on Alcator C-Mod was developed and installed for the 2009 run campaign. Its design included capabilities for multiple impurity injections during a single plasma pulse and remote manipulation of the ablated spot size. The system uses a 0.68 J, Nd:YAG laser operating at up to 10 Hz coupled with the fast beam steering via a 2D piezoelectric mirror mount able to move spot locations in the 100 ms between laser pulses and a remote controllable optical train that allow ablated spot sizes to vary from ∼0.5 to 7 mm. The ability to ablate a wide range in target Z along with Alcator C-Mod's extensive diagnostic capabilities (soft x-ray, vacuum ultraviolet (VUV), charge exchange spectroscopy, etc.) allows for detailed studies of the impurity transport dependencies and mechanisms. This system has demonstrated the achievement of all its design goals including the ability for non-perturbative operation allowing for insight into underlying impurity transport processes. A detailed overview of the laser blow-off system and initial results of operation are presented. This includes an investigation into the characterization of impurity confinement in the I-mode confinement regime recently investigated on C-Mod.

  19. Busulfan Injection

    MedlinePlus

    Busulfex® Injection ... Busulfan injection is used to treat a certain type of chronic myelogenous leukemia (CML; a type of cancer of ... of 16 doses) before bone marrow transplant.Busulfan injection may cause seizures during therapy with the medication. ...

  20. Stretching micropatterned cells on a PDMS membrane.

    PubMed

    Carpi, Nicolas; Piel, Matthieu

    2014-01-22

    Mechanical forces exerted on cells and/or tissues play a major role in numerous processes. We have developed a device to stretch cells plated on a PolyDiMethylSiloxane (PDMS) membrane, compatible with imaging. This technique is reproducible and versatile. The PDMS membrane can be micropatterned in order to confine cells or tissues to a specific geometry. The first step is to print micropatterns onto the PDMS membrane with a deep UV technique. The PDMS membrane is then mounted on a mechanical stretcher. A chamber is bound on top of the membrane with biocompatible grease to allow gliding during the stretch. The cells are seeded and allowed to spread for several hours on the micropatterns. The sample can be stretched and unstretched multiple times with the use of a micrometric screw. It takes less than a minute to apply the stretch to its full extent (around 30%). The technique presented here does not include a motorized device, which is necessary for applying repeated stretch cycles quickly and/or computer controlled stretching, but this can be implemented. Stretching of cells or tissue can be of interest for questions related to cell forces, cell response to mechanical stress or tissue morphogenesis. This video presentation will show how to avoid typical problems that might arise when doing this type of seemingly simple experiment.

  1. A Study of Pulsed Blowing Effect on Flow Separation over Flap

    NASA Astrophysics Data System (ADS)

    Wang, Yankui; Zhou, Ping; Li, Qian

    2015-11-01

    With the development of the modern aircraft, such as tailless flying configuration, traditional flaps are also the main control surfaces for flight controlling. However, the efficiency of the flap is not only descent quickly due to flow separation over itself under higher deflection angle of flap, but also is evidently influenced by the flow coming down from the upstream wing. A novel flow control technique to improve the flow separation over the flap by pulsed blowing is investigated in this paper by wind tunnel test under Reynolds number of 0.6* 10E6 2.4* 10E6. To begin with, the control performance for flow separation over the flap is very sensitive to the blowing position and direction and the flow separation can be recovered by the pulsed blowing evidently. Secondly, the pulsed blowing efficiency is 30% higher than that of continuous blowing with the same consumption. In addition, the pulsed blowing efficiency increases quickly with the increasing of pulsed blowing frequency and keep constant gradually when the pulsed blowing Stroul number is bigger than 0.6. National Natural Science Foundation of China (11272035).

  2. Awareness and Ethical Orientation of Alternatively Certified Prospective Teachers to Intention for Whistle Blowing

    ERIC Educational Resources Information Center

    Toker Gokce, Asiye

    2013-01-01

    This study inquires whistle blowing intentions of alternatively certified prospective teachers, investigating their moral reasoning to blow the whistle. Specifically three hypotheses were tested: Overall ethical awareness of the alternatively certified prospective teachers is high; the participants will identify reasons related to philosophical…

  3. Solution blow-up for a class of parabolic equations with double nonlinearity

    SciTech Connect

    Korpusov, Maxim O

    2013-03-31

    We consider a class of parabolic-type equations with double nonlinearity and derive sufficient conditions for finite time blow-up of its solutions in a bounded domain under the homogeneous Dirichlet condition. To prove the solution blow-up we use a modification of Levine's method. Bibliography: 13 titles.

  4. Motion of Particles in a Gas Stream in the Presence of Tangential and Axial Blowing

    NASA Astrophysics Data System (ADS)

    Teplitskii, Yu. S.; Pitsukha, E. A.; Prokopovich, O. V.

    2016-03-01

    Radial distributions of the velocity components of particles in a vertical vortex chamber in the presence of axial (bottom) blowing under conditions of quasi-solid rotation are considered, and the dependence of the particle rotation frequency on the Stokes number and the fraction of bottom blowing has been established.

  5. Shooting method for solution of boundary-layer flows with massive blowing

    NASA Technical Reports Server (NTRS)

    Liu, T.-M.; Nachtsheim, P. R.

    1973-01-01

    A modified, bidirectional shooting method is presented for solving boundary-layer equations under conditions of massive blowing. Unlike the conventional shooting method, which is unstable when the blowing rate increases, the proposed method avoids the unstable direction and is capable of solving complex boundary-layer problems involving mass and energy balance on the surface.

  6. [Stretching--do current explanatory models suffice?].

    PubMed

    Freiwald, J; Engelhardt, M; Jäger, M; Gnewuch, A; Reuter, I; Wiemann, K; Starischka, S

    1998-06-01

    The opinion that mobility in the usual performance if the "straight leg raise" test for the evaluation of stretching techniques is subject to solety muscular limitations is critically appraised. With integration of recent results from molecular biological research and our own measurements, we can show that not only mechanical but also neurophysiological factors must be considered in the limitation of mobility. In the majority of the examined patients stretching of the ischiadic nerve seems to be responsible for restrictions in movement. The presented results cast doubt on the currently held assumptions and basic principles of stretching in therapy and sport.

  7. Stretching and injury prevention: an obscure relationship.

    PubMed

    Witvrouw, Erik; Mahieu, Nele; Danneels, Lieven; McNair, Peter

    2004-01-01

    It is generally accepted that increasing the flexibility of a muscle-tendon unit promotes better performances and decreases the number of injuries. Stretching exercises are regularly included in warm-up and cooling-down exercises; however, contradictory findings have been reported in the literature. Several authors have suggested that stretching has a beneficial effect on injury prevention. In contrast, clinical evidence suggesting that stretching before exercise does not prevent injuries has also been reported. Apparently, no scientifically based prescription for stretching exercises exists and no conclusive statements can be made about the relationship of stretching and athletic injuries. Stretching recommendations are clouded by misconceptions and conflicting research reports. We believe that part of these contradictions can be explained by considering the type of sports activity in which an individual is participating. Sports involving bouncing and jumping activities with a high intensity of stretch-shortening cycles (SSCs) [e.g. soccer and football] require a muscle-tendon unit that is compliant enough to store and release the high amount of elastic energy that benefits performance in such sports. If the participants of these sports have an insufficient compliant muscle-tendon unit, the demands in energy absorption and release may rapidly exceed the capacity of the muscle-tendon unit. This may lead to an increased risk for injury of this structure. Consequently, the rationale for injury prevention in these sports is to increase the compliance of the muscle-tendon unit. Recent studies have shown that stretching programmes can significantly influence the viscosity of the tendon and make it significantly more compliant, and when a sport demands SSCs of high intensity, stretching may be important for injury prevention. This conjecture is in agreement with the available scientific clinical evidence from these types of sports activities. In contrast, when the type

  8. Stretching DNA with optical tweezers.

    PubMed Central

    Wang, M D; Yin, H; Landick, R; Gelles, J; Block, S M

    1997-01-01

    Force-extension (F-x) relationships were measured for single molecules of DNA under a variety of buffer conditions, using an optical trapping interferometer modified to incorporate feedback control. One end of a single DNA molecule was fixed to a coverglass surface by means of a stalled RNA polymerase complex. The other end was linked to a microscopic bead, which was captured and held in an optical trap. The DNA was subsequently stretched by moving the coverglass with respect to the trap using a piezo-driven stage, while the position of the bead was recorded at nanometer-scale resolution. An electronic feedback circuit was activated to prevent bead movement beyond a preset clamping point by modulating the light intensity, altering the trap stiffness dynamically. This arrangement permits rapid determination of the F-x relationship for individual DNA molecules as short as -1 micron with unprecedented accuracy, subjected to both low (approximately 0.1 pN) and high (approximately 50 pN) loads: complete data sets are acquired in under a minute. Experimental F-x relationships were fit over much of their range by entropic elasticity theories based on worm-like chain models. Fits yielded a persistence length, Lp, of approximately 47 nm in a buffer containing 10 mM Na1. Multivalent cations, such as Mg2+ or spermidine 3+, reduced Lp to approximately 40 nm. Although multivalent ions shield most of the negative charges on the DNA backbone, they did not further reduce Lp significantly, suggesting that the intrinsic persistence length remains close to 40 nm. An elasticity theory incorporating both enthalpic and entropic contributions to stiffness fit the experimental results extremely well throughout the full range of extensions and returned an elastic modulus of approximately 1100 pN. Images FIGURE 1 FIGURE 2 PMID:9138579

  9. Tangential blowing for control of strong normal shock - Boundary layer interactions on inlet ramps

    NASA Technical Reports Server (NTRS)

    Schwendemann, M. F.; Sanders, B. W.

    1982-01-01

    The use of tangential blowing from a row of holes in an aft facing step is found to provide good control of the ramp boundary layer, normal shock interaction on a fixed geometry inlet over a wide range of inlet mass flow ratios. Ramp Mach numbers of 1.36 and 1.96 are investigated. The blowing geometry is found to have a significant effect on system performance at the highest Mach number. The use of high-temperature air in the blowing system, however, has only a slight effect on performance. The required blowing rates are significantly high for the most severe test conditions. In addition, the required blowing coefficient is found to be proportional to the normal shock pressure rise.

  10. Flow visualization studies of blowing from the tip of a swept wing

    NASA Technical Reports Server (NTRS)

    Smith, Jeannette W.; Mineck, Raymond E.; Neuhart, Dan H.

    1990-01-01

    Flow visualization studies of blowing from the tip of a swept wing were conducted in the Langley 16- by 24-inch water tunnel. Four wing tips, each with two independent blowing slots, were tested. The two slots were located one behind the other in the chordwise direction. The wing tips were designed to vary systematically the jet length, the jet in-plane exhaust direction (sweep), and the jet out-of-plane exhaust direction (anhedral). Each blowing slot was tested separately at two angles of attack and at four ratios of jet to free stream velocity ratios. Limited tests were conducted with blowing from both slots simultaneously. Blowing from the tip inhibited inboard spanwise flow on the upper wing surface near the tip. The jet path moved farther away from the tip with increasing jet to free stream velocity ratio and moved closer to the tip with increasing angle of attack.

  11. Computational Investigation of Tangential Slot Blowing on a Generic Chined Forebody

    NASA Technical Reports Server (NTRS)

    Agosta-Greenman, Roxana M.; Gee, Ken; Cummings, Russell M.; Schiff, Lewis B.

    1995-01-01

    The effect of tangential slot blowing on the flowfield about a generic chined forebody at high angles of attack is investigated numerically using solutions of the thin-layer, Reynolds-averaged, Navier-Stokes equations. The effects of jet mass now ratios, angle of attack, and blowing slot location in the axial and circumferential directions are studied. The computed results compare well with available wind-tunnel experimental data. Computational results show that for a given mass now rate, the yawing moments generated by slot blowing increase as the body angle of attack increases. It is observed that greater changes in the yawing moments are produced by a slot located closest to the lip of the nose. Also, computational solutions show that inboard blowing across the top surface is more effective at generating yawing moments than blowing outboard from the bottom surface.

  12. Effect of modified hold-relax stretching and static stretching on hamstring muscle flexibility.

    PubMed

    Ahmed, Hashim; Iqbal, Amir; Anwer, Shahnawaz; Alghadir, Ahmad

    2015-02-01

    [Purpose] The aim of present study was to compare the effectiveness of modified hold-relax stretching and static stretching in improving the hamstring muscle flexibility. [Subjects and Methods] Forty-five male subjects with hamstring tightness were included in this study. The subjects were randomly placed into three groups: the modified hold-relax stretching, static stretching and control groups. The modified hold-relax stretching group performed 7 seconds of isometric contraction and then relaxed for 5 seconds, and this was repeated five times daily for five consecutive days. The static stretching group received 10 minutes of static stretching with the help of a pulley and weight system for five consecutive days. The control group received only moist heat for 20 minutes for five consecutive days. A baseline reading of passive knee extension (PKE) was taken prior to the intervention; rest measurements were taken immediate post intervention on day 1, day 3, day 5, and after a 1 week follow-up, i.e., at the 12th day. [Results] On comparing the baseline readings of passive knee extension (PKE), there was no difference noted between the three groups. On comparing the posttest readings on day 5 between the 3 groups, a significant difference was noted. However, post hoc analysis revealed an insignificant difference between the modified hold-relax stretching and static stretching groups. There was a significant difference between the static stretching and control groups and between the modified hold-relax stretching and control groups. [Conclusion] The results of this study indicate that both the modified hold-relax stretching technique and static stretching are equally effective, as there was no significant difference in improving the hamstring muscle flexibility between the two groups.

  13. Recent activities on CCMHD power generation studies with Fuji-1 blow-down facility

    SciTech Connect

    Okuno, Y.; Okamura, T.; Yoshikawa, K.

    1995-12-31

    Recent activities on experimental studies with closed cycle MBD {open_quotes}Fuji-1{open_quotes} blow-down facility at Tokyo Institute of Technology are presented. A new disk generator ( Disk-F4 ) has been installed and a new seed injection system has been introduced from IVTAN (Institute of High Temperature in Russia) in 1994.The design concept of the new generator channel is focused mainly on the reliability of high power generation. The Mach number at the generator inlet and the thermal input are increased up to {approximately}2.8 and {approximately}3.0 MW, respectively. In the new seeding system, a melted seed material is pushed by a piston dozator, instead of gas-pressure-driven in the previous system. The controllability of seed fraction is markedly improved, and the large fluctuation as has been observed previously is diminished, although the spatial non-uniformity of seed fraction which could occur in the all previous experiments is observed. In the power generation experiments with the new components, the maximum power output of 502 kW and the enthalpy extraction ratio of 16.7% have been obtained. These values at the present stage are lower than the maximum values previously achieved in the facility. However, the reliable high power generation can be expected for the new generator.

  14. UMC designed to stretch technology

    SciTech Connect

    Steven, R.R.

    1982-02-01

    Shell/Esso's decision to install its advanced Underwater Manifold Center (UMC) in the Central Cormorant field in the UK sector of the North Sea will prove a whole range of component subsea technologies. The basic functions of UMC are: the drilling of wells through the base structure and tie-in satellites; the collection of fluids from production wells for delivery to the South Cormorant platform 4.5 miles away; the distribution of treated seawater from the platform to selected injection wells and the maintenance of valves and controls without the use of divers. The basis for the design was a nine-well manifold with each well bay able to be used either for template or satellite wells which could be either producers or water injectors. On Central Cormorant all the well completions will have two 3-in.-ID tubing strings, each with a tubing retrievable subsurface safety valve. The production manifold on the UMC is situated along each side of the maintenance vehicle track, which runs down the center of the base structure. It has an 8-in. oil header for collecting oil production, an 8-in. water injection header and two 3-in. headers for well testing and TFL access. In all there are 110 valves and diverters. An insulated pipe-within-a pipe was developed for flowlines. The control system was a multiplexed electro-hydraulic set up. Verification tests have been run. (DP)

  15. Testosterone and progesterone concentrations in blow samples are biologically relevant in belugas (Delphinapterus leucas).

    PubMed

    Richard, Justin T; Robeck, Todd R; Osborn, Steven D; Naples, Lisa; McDermott, Alexa; LaForge, Robert; Romano, Tracy A; Sartini, Becky L

    2016-12-16

    Steroid hormone analysis in blow (respiratory vapor) may provide a minimally invasive way to assess the reproductive status of wild cetaceans. Biological validation of the method is needed to allow for the interpretation of hormone measurements in blow samples. Utilizing samples collected from trained belugas (Delphinapterus leucas, n=20), enzyme immunoassays for testosterone and progesterone were validated for use with beluga blow samples. Testosterone concentrations in 40 matched blood and blow samples collected from 4 male belugas demonstrated a positive correlation (R(2)=0.52, p<0.0001). Progesterone concentrations in 64 matching blood and blow samples from 11 females were also positively correlated (R(2)=0.60, p<0.0001). Testosterone concentrations (mean±SD) in blow samples collected from adult males (119.3±14.2pg/ml) were higher (p<0.01) than that of a juvenile male (<8years) (59.4±6.5pg/ml) or female belugas (54.1±25.7pg/ml). Among adult males, testosterone concentrations in blow demonstrated a seasonal pattern of secretion, with peak secretion occurring during the breeding season (February-April, 136.95±33.8pg/ml). Progesterone concentrations in blow varied by reproductive status; pregnant females (410.6±87.8pg/ml) and females in the luteal phase of the estrous cycle (339.5±51.0pg/ml) had higher (p<0.0001) blow progesterone concentrations than non-pregnant females without a corpus luteum (242.5±27.3pg/ml). Results indicate that blow sample analysis can be used to detect variation in reproductive states associated with large differences in circulating testosterone or progesterone in belugas.

  16. Demonstrating the Stretch Reflex: A Mechanical Model.

    ERIC Educational Resources Information Center

    Batavia, Mitchell; McDonough, Andrew L.

    2000-01-01

    Explains the concept of stretch reflexes to students using a mechanical model. The model provides a dynamic multisensory experience using movement, light, and sound. Describes the construction design. (SAH)

  17. Soot blower using fuel gas as blowing medium

    DOEpatents

    Tanca, Michael C.

    1982-01-01

    A soot blower assembly (10) for use in combination with a coal gasifier (14). The soot blower assembly is adapted for use in the hot combustible product gas generated in the gasifier as the blowing medium. The soot blower lance (20) and the drive means (30) by which it is moved into and out of the gasifier is housed in a gas tight enclosure (40) which completely surrounds the combination. The interior of the enclosure (40) is pressurized by an inert gas to a pressure level higher than that present in the gasifier so that any combustible product gas leaking from the soot blower lance (20) is forced into the gasifier rather than accumulating within the enclosure.

  18. Blow-down analysis of helium from a cryogenic dewar

    NASA Technical Reports Server (NTRS)

    Khan, H. J.; Zhang, Q. Q.; Rhee, M.; Figueroa, O.

    1992-01-01

    NASA is currently developing Space Shuttle-based refilling of helium using superfluid helium on-orbit transfer (SHOOT). All the critical components of SHOOT need to be developed through ground-based tests. The helium dewar is one of these components. The Dewar consists of a vacuum vessel enclosing a superinsulated tank. The space between the vacuum vessel and the liquid tank is considered a common vacuum space. In the event that the vacuum is lost, the heat transfers to the dewar and the pressure inside the dewar increases rapidly, resulting in rupture of the dewar due to excessive pressure. Therefore, an emergency vent line is required for release of helium to prevent the dewar from rupturing. The study describes a numerical model for blow-down analysis in an emergency. This qualifies the design of the emergency vent line to be adequate for the assumed heat loads to the helium dewar.

  19. MR imaging of orbital blow-out fractures.

    PubMed

    McArdle, C B; Amparo, E G; Mirfakhraee, M

    1986-01-01

    We report on a case of orbital blow-out fractures involving the medial and inferior walls. In this case conventional multiplanar 8 mm thick sections with magnetic resonance (MR) imaging proved to be more helpful than 1.5 mm axial thin sections with CT in demonstrating the extent of orbital floor herniation of fat. Entrapment of muscle was excluded. Oblique sagittal views were most helpful in evaluating the orbital floor, since the full course of the inferior rectus muscle is seen. Additionally, the optic nerve is seen along its entire length. Masking of intraorbital contents by isodense hemorrhage on CT studies apparently is not a problem with MR imaging if hemorrhage is small or nonacute.

  20. Reduction of Flap Side Edge Noise - the Blowing Flap

    NASA Technical Reports Server (NTRS)

    Hutcheson, Florence V.; Brooks, THomas F.

    2005-01-01

    A technique to reduce the noise radiating from a wing-flap side edge is being developed. As an airplane wing with an extended flap is exposed to a subsonic airflow, air is blown outward through thin rectangular chord-wise slots at various locations along the side edges and side surface of the flap to weaken and push away the vortices that originate in that region of the flap and are responsible for important noise emissions. Air is blown through the slots at up to twice the local flow velocity. The blowing is done using one or multiple slots, where a slot is located along the top, bottom or side surface of the flap along the side edge, or also along the intersection of the bottom (or top) and side surfaces.

  1. Skin Friction Reduction by Micro-Blowing Technique

    NASA Technical Reports Server (NTRS)

    Hwang, Danny P. (Inventor)

    1998-01-01

    A system and method for reducing skin friction of an object in relative motion to a fluid. A skin forming a boundary between the object and the fluid, the skin having holes through which micro-blowing of air is blown and a transmitting mechanism for transmitting air through the skin. The skin has an inner layer and an outer layer. the inner layer being a low permeable porous sheet, the outer layer being a plate having high aspect ratio high porosity. and small holes. The system may further include a suction apparatus for suctioning air from the outer layer. The method includes the steps of transmitting air through the inner layer and passing the air transmitted through the inner layer to the outer layer. The method may further include the step of bleeding air off the outer layer using the suction apparatus.

  2. Blow-down analysis of helium from a cryogenic dewar

    NASA Astrophysics Data System (ADS)

    Khan, H. J.; Zhang, Q. Q.; Rhee, M.; Figueroa, O.

    NASA is currently developing Space Shuttle-based refilling of helium using superfluid helium on-orbit transfer (SHOOT). All the critical components of SHOOT need to be developed through ground-based tests. The helium dewar is one of these components. The Dewar consists of a vacuum vessel enclosing a superinsulated tank. The space between the vacuum vessel and the liquid tank is considered a common vacuum space. In the event that the vacuum is lost, the heat transfers to the dewar and the pressure inside the dewar increases rapidly, resulting in rupture of the dewar due to excessive pressure. Therefore, an emergency vent line is required for release of helium to prevent the dewar from rupturing. The study describes a numerical model for blow-down analysis in an emergency. This qualifies the design of the emergency vent line to be adequate for the assumed heat loads to the helium dewar.

  3. 22. Blow Down Valve for Unit 1, view to the ...

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

    22. Blow Down Valve for Unit 1, view to the southwest. This valve allows the water in the draft chest to be lowered (i.e., 'blown down') so that the unit can be motored (i.e., run like an electric motor rather than an electric power generator). The valve is operated by pressure from the instrument air system (part of which is visible in photograph MT-105-A-17 above), but the unit draws on the station air system (see photograph MT-105-A-24 below) to lower the water in the draft chest. - Washington Water Power Clark Fork River Noxon Rapids Hydroelectric Development, Powerhouse, South bank of Clark Fork River at Noxon Rapids, Noxon, Sanders County, MT

  4. Comparison of two stretching methods and optimization of stretching protocol for the piriformis muscle.

    PubMed

    Gulledge, Brett M; Marcellin-Little, Denis J; Levine, David; Tillman, Larry; Harrysson, Ola L A; Osborne, Jason A; Baxter, Blaise

    2014-02-01

    Piriformis syndrome is an uncommon diagnosis for a non-discogenic form of sciatica whose treatment has traditionally focused on stretching the piriformis muscle (PiM). Conventional stretches include hip flexion, adduction, and external rotation. Using three-dimensional modeling, we quantified the amount of (PiM) elongation resulting from two conventional stretches and we investigated by use of a computational model alternate stretching protocols that would optimize PiM stretching. Seven subjects underwent three CT scans: one supine, one with hip flexion, adduction, then external rotation (ADD stretch), and one with hip flexion, external rotation, then adduction (ExR stretch). Three-dimensional bone models were constructed from the CT scans. PiM elongation during these stretches, femoral neck inclination, femoral head anteversion, and trochanteric anteversion were measured. A computer program was developed to map PiM length over a range of hip joint positions and was validated against the measured scans. ExR and ADD stretches elongated the PiM similarly by approximately 12%. Femoral head and greater trochanter anteversion influenced PiM elongation. Placing the hip joints in 115° of hip flexion, 40° of external rotation and 25° of adduction or 120° of hip flexion, 50° of external rotation and 30° of adduction increased PiM elongation by 30-40% compared to conventional stretches (15.1 and 15.3% increases in PiM muscle length, respectively). ExR and ADD stretches elongate the PiM similarly and therefore may have similar clinical effectiveness. The optimized stretches led to larger increases in PiM length and may be more easily performed by some patients due to increased hip flexion.

  5. Wagon loads of sand blows in White County, Illinois

    USGS Publications Warehouse

    Hough, S.E.; Bilham, R.; Mueller, K.; Stephenson, W.; Williams, R.; Odum, J.

    2005-01-01

    Several anecdotal accounts provide compelling evidence that liquefaction occurred at several sites in Illinois during the 1811-1812 New Madrid sequence, as much as 250 km north of the New Madrid seismic zone (NMSZ). At one Wabash Valley location, sand blows are still evident near Big Prairie, Illinois, a location described in a particularly detailed and precise historic account. This account includes descriptions of substantial liquefaction (sand blows) as well as a two-mile-long east-west-trending "crack" along which two feet of south-side-down displacement occurred. An offset can no longer be seen at this location, which has been extensively farmed and plowed for decades. Field reconnaissance verifies many of the details provided in the account, however. We conducted a seismic-reflection experiment at this location and observed a modest offset in the Paleozoic strata at this location. The offset is opposite to that described in the historic account, consistent with the hypothesis that large midcontinent earthquakes occur on faults reactivated in a Holocene stress regime different from the one in which they were formed. Only two explanations can account for these observations: Either large NMSZ events triggered substantial liquefaction at distances greater than hitherto realized, or at least one large "New Madrid" event occurred significantly north of the NMSZ. We explore these possibilities and conclude that, while neither one can be ruled out, several disparate lines of evidence suggest that the 23 January 1812 "New Madrid mainshock" occurred in White County, Illinois, near the location of the mb 5.5 1968 southern Illinois earthquake and recent microearthquake activity.

  6. New approach to the exact solution of viscous flow due to stretching (shrinking) and porous sheet

    NASA Astrophysics Data System (ADS)

    Ali, Azhar; Khan Marwat, Dil Nawaz; Asghar, S.

    Exact analytical solutions for the generalized stretching (shrinking) of a porous surface, for the variable suction (injection) velocity, is presented in this paper. The solution is generalized in the sense that the existing solutions that correspond to various stretching velocities are recovered as a special case of this study. A suitable similarity transformation is introduced to find self-similar solution of the non-linear governing equations. The flow is characterized by a few non-dimensional parameters signifying the problem completely. These parameters are such that the whole range of stretching (shrinking) problems discussed earlier can be recovered by assigning appropriate values to these parameters. A key point of the whole narrative is that a number of earlier works can be abridged into one generalized problem through the introduction of a new similarity transformation and finding its exact solution encompassing all the earlier solutions.

  7. Turbine vane gas film cooling with injection in the leading edge region from a single row of spanwise angled holes

    NASA Technical Reports Server (NTRS)

    Lecuyer, M. R.; Hanus, G. J.

    1976-01-01

    An experimental study of gas film cooling was conducted on a 3X size model turbine vane. Injection in the leading edge region was from a single row of holes angled in a spanwise direction. Measurements of the local heat flux downstream from the row of coolant holes, both with and without film coolant flow, were used to determine the film cooling performance presented in terms of the Stanton number ratio. Results for a range of coolant blowing ratio, M = 0 to 2.0, indicate a reduction in heat flux of up to 15 to 30 percent at a point 10 to 11 hole diameters downstream from injection. An optimum coolant blowing ratio corresponds to a coolant-to-freestream velocity ratio in the range of 0.5. The shallow injection angle resulted in superior cooling performance for injection closest to stagnation, while the effect of injection angle was insignificant for injection further from stagnation.

  8. Numerical study of the trailing vortex of a wing with wing-tip blowing

    NASA Technical Reports Server (NTRS)

    Lim, Hock-Bin

    1994-01-01

    Trailing vortices generated by lifting surfaces such as helicopter rotor blades, ship propellers, fixed wings, and canard control surfaces are known to be the source of noise, vibration, cavitation, degradation of performance, and other hazardous problems. Controlling these vortices is, therefore, of practical interest. The formation and behavior of the trailing vortices are studied in the present research. In addition, wing-tip blowing concepts employing axial blowing and spanwise blowing are studied to determine their effectiveness in controlling these vortices and their effects on the performance of the wing. The 3D, unsteady, thin-layer compressible Navier-Stokes equations are solved using a time-accurate, implicit, finite difference scheme that employs LU-ADI factorization. The wing-tip blowing is simulated using the actuator plane concept, thereby, not requiring resolution of the jet slot geometry. Furthermore, the solution blanking feature of the chimera scheme is used to simplify the parametric study procedure for the wing-tip blowing. Computed results are shown to compare favorably with experimental measurements. It is found that axial wing-tip blowing, although delaying the rolling-up of the trailing vortices and the near-field behavior of the flowfield, does not dissipate the circulation strength of the trailing vortex farther downstream. Spanwise wing-tip blowing has the effect of displacing the trailing vortices outboard and upward. The increased 'wing-span' due to the spanwise wing-tip blowing has the effect of lift augmentation on the wing and the strengthening of the trailing vortices. Secondary trailing vortices are created at high spanwise wing-tip blowing intensities.

  9. An experimental investigation of leading-edge vortex augmentation by blowing

    NASA Technical Reports Server (NTRS)

    Bradley, R. G.; Wray, W. O.; Smith, C. W.

    1974-01-01

    A wind tunnel test was conducted to determine the effects of over-the-wing blowing as a means of augmenting the leading-edge vortex flow of several pointed-tip, sharp-edged planforms. Arrow, delta, and diamond wings with leading-edge sweeps of 30 and 45 degrees were mounted on a body-of-revolution fuselage and tested in a low-speed wind tunnel at a Mach number of 0.2. Nozzle location data, pitch data, and flow-visualization pictures were obtained for a range of blowing rates. Results show pronounced increases in vortex lift due to the blowing.

  10. Flap noise measurements for STOL configurations using external upper surface blowing

    NASA Technical Reports Server (NTRS)

    Dorsch, R. G.; Reshotko, M.; Olsen, W. A.

    1972-01-01

    Screening tests of upper surface blowing on externally blown flaps configurations were conducted. Noise and turning effectiveness data were obtained with small-scale, engine-over-the-wing models. One large model was tested to determine scale effects. Nozzle types included circular, slot, D-shaped, and multilobed. Tests were made with and without flow attachment devices. For STOL applications the particular multilobed mixer and the D-shaped nozzles tested were found to offer little or no noise advantage over the round convergent nozzle. High aspect ratio slot nozzles provided the quietest configurations. In general, upper surface blowing was quieter than lower surface blowing for equivalent EBF models.

  11. On the blow-up solutions for the nonlinear fractional Schrödinger equation

    NASA Astrophysics Data System (ADS)

    Zhu, Shihui

    2016-07-01

    This paper is dedicated to the blow-up solutions for the nonlinear fractional Schrödinger equation arising from pseudorelativistic Boson stars. First, we compute the best constant of a gG-N inequality by the profile decomposition theory and variational arguments. Then, we find the sharp threshold mass of the existence of finite-time blow-up solutions. Finally, we study the dynamical properties of finite-time blow-up solutions around the sharp threshold mass by giving a refined compactness lemma.

  12. Stable Self-Similar Blow-Up Dynamics for Slightly {L^2}-Supercritical Generalized KDV Equations

    NASA Astrophysics Data System (ADS)

    Lan, Yang

    2016-07-01

    In this paper we consider the slightly {L^2}-supercritical gKdV equations {partial_t u+(u_{xx}+u|u|^{p-1})_x=0}, with the nonlinearity {5 < p < 5+\\varepsilon} and {0 < \\varepsilon≪ 1}. We will prove the existence and stability of a blow-up dynamics with self-similar blow-up rate in the energy space {H^1} and give a specific description of the formation of the singularity near the blow-up time.

  13. Musculoskeletal Injection

    PubMed Central

    Wittich, Christopher M.; Ficalora, Robert D.; Mason, Thomas G.; Beckman, Thomas J.

    2009-01-01

    Patients commonly present to primary care physicians with musculoskeletal symptoms. Clinicians certified in internal medicine must be knowledgeable about the diagnosis and management of musculoskeletal diseases, yet they often receive inadequate postgraduate training on this topic. The musculoskeletal problems most frequently encountered in our busy injection practice involve, in decreasing order, the knees, trochanteric bursae, and glenohumeral joints. This article reviews the clinical presentations of these problems. It also discusses musculoskeletal injections for these problems in terms of medications, indications, injection technique, and supporting evidence from the literature. Experience with joint injection and the pharmacological principles described in this article should allow primary care physicians to become comfortable and proficient with musculoskeletal injections. PMID:19720781

  14. Oxygen and carbon discovered in exoplanet atmosphere `blow-off'

    NASA Astrophysics Data System (ADS)

    2004-02-01

    Oxygen and carbon discovered in exoplanet atmosphere ‘blow-off’ hi-res Size hi-res: 1096 kb Credits: ESA/Alfred Vidal-Madjar (Institut d’Astrophysique de Paris, CNRS, France) Oxygen and carbon discovered in exoplanet atmosphere ‘blow-off’ This artist’s impression shows an extended ellipsoidal envelope - the shape of a rugby-ball - of oxygen and carbon discovered around the well-known extrasolar planet HD 209458b. An international team of astronomers led by Alfred Vidal-Madjar (Institut d’Astrophysique de Paris, CNRS, France) observed the first signs of oxygen and carbon in the atmosphere of a planet beyond our Solar System for the first time using the NASA/ESA Hubble Space Telescope. The atoms of carbon and oxygen are swept up from the lower atmosphere with the flow of escaping atmospheric atomic hydrogen - like dust in a supersonic whirlwind - in a process called atmospheric ‘blow off’. Oxygen and carbon have been detected in the atmosphere of a planet beyond our Solar System for the first time. Scientists using the NASA/ESA Hubble Space Telescope have observed the famous extrasolar planet HD 209458b passing in front of its parent star, and found oxygen and carbon surrounding the planet in an extended ellipsoidal envelope - the shape of a rugby-ball. These atoms are swept up from the lower atmosphere with the flow of the escaping atmospheric atomic hydrogen, like dust in a supersonic whirlwind. The team led by Alfred Vidal-Madjar (Institut d’Astrophysique de Paris, CNRS, France) reports this discovery in a forthcoming issue of Astrophysical Journal Letters. The planet, called HD 209458b, may sound familiar. It is already an extrasolar planet with an astounding list of firsts: the first extrasolar planet discovered transiting its sun, the first with an atmosphere, the first observed to have an evaporating hydrogen atmosphere (in 2003 by the same team of scientists) and now the first to have an atmosphere containing oxygen and carbon. Furthermore

  15. Does motor imagery enhance stretching and flexibility?

    PubMed

    Guillot, Aymeric; Tolleron, Coralie; Collet, Christian

    2010-02-01

    Although several studies have demonstrated that motor imagery can enhance learning processes and improve motor performance, little is known about its effect on stretching and flexibility. The increased active and passive range of motion reported in preliminary research has not been shown to be elicited by motor imagery training alone. We thus compared flexibility scores in 21 synchronized swimmers before and after a 5-week mental practice programme that included five stretching exercises in active and passive conditions. The imagery training programme resulted in selective increased flexibility, independently of the stretching method. Overall, the improvement in flexibility was greater in the imagery group than in the control group for the front split (F(1,18) = 4.9, P = 0.04), the hamstrings (F(1,18) = 5.2, P = 0.035), and the ankle stretching exercises (F(1,18) = 5.6, P = 0.03). There was no difference in shoulders and side-split flexibility (F(1,18) = 0.1, P = 0.73 and F(1,18) = 3.3, P = 0.08 respectively). Finally, there was no correlation between individual imagery ability and improvement in flexibility. Psychological and physiological effects of motor imagery could explain the increase in range of motion, suggesting that imagery enhances joint flexibility during both active and passive stretching.

  16. Movement and stretching imagery during flexibility training.

    PubMed

    Vergeer, Ineke; Roberts, Jenny

    2006-02-01

    The aim of this study was to examine the effect of movement and stretching imagery on increases in flexibility. Thirty volunteers took part in a 4 week flexibility training programme. They were randomly assigned to one of three groups: (1) movement imagery, where participants imagined moving the limb they were stretching; (2) stretching imagery, where participants imagined the physiological processes involved in stretching the muscle; and (3) control, where participants did not engage in mental imagery. Active and passive range of motion around the hip was assessed before and after the programme. Participants provided specific ratings of vividness and comfort throughout the programme. Results showed significant increases in flexibility over time, but no differences between the three groups. A significant relationship was found, however, between improved flexibility and vividness ratings in the movement imagery group. Furthermore, both imagery groups scored significantly higher than the control group on levels of comfort, with the movement imagery group also scoring significantly higher than the stretching imagery group. We conclude that the imagery had stronger psychological than physiological effects, but that there is potential for enhancing physiological effects by maximizing imagery vividness, particularly for movement imagery.

  17. What Protects Certain Nerves from Stretch Injury?

    PubMed

    Schraut, Nicholas B; Walton, Sharon; Bou Monsef, Jad; Shott, Susan; Serici, Anthony; Soulii, Lioubov; Amirouche, Farid; Gonzalez, Mark H; Kerns, James M

    2016-01-01

    The human tibial nerves is less prone to injury following joint arthroplasty compared with the peroneal nerves. Besides the anatomical distribution, other features may confer protection from stretch injury. We therefore examined the size, shape and connective tissue distribution for the two nerves. The tibial and peroneal nerves from each side of nine fresh human cadavers we reharvested mid-thigh. Proximal segments manually stretched 20%-25% were fixed in aldehyde, while the adjacent distal segments were fixed in their natural length. Paraffin sections stained by Masson's trichrome method for connective tissue were examined by light microscopy. Tibial nerves had 2X more fascicles compared with the peroneal, but the axonal content appeared similar. Analysis showed that neither nerve had a significant reduction in cross sectional area of the fascicles following stretch. However, fascicles from stretched tibial nerves become significantly more oval compared with those from unstretched controls and peroneal nerves. Tibial nerves had a greater proportion that was extrafascicular tissue (50-55%) compared with peroneal nerves (38%-42%). This epineurium was typically adipose tissue. Perineurial thickness in both nerves was directly related to fascicular size. Tibial nerves have several unique histological features associated with size, shape and tissue composition compared with the peroneal nerve. We suggest that more fascicles with their tightly bound perineurium and more robust epineurium afford protection against stretch injury. Mechanical studies should clarify how size and shape contribute to nerve protection and/or neurapraxia.

  18. Altered activation patterns by triceps surae stretch reflex pathways in acute and chronic spinal cord injury.

    PubMed

    Frigon, Alain; Johnson, Michael D; Heckman, C J

    2011-10-01

    Spinal reflexes are modified by spinal cord injury (SCI) due the loss of excitatory inputs from supraspinal structures and changes within the spinal cord. The stretch reflex is one of the simplest pathways of the central nervous system and was used presently to evaluate how inputs from primary and secondary muscle spindles interact with spinal circuits before and after spinal transection (i.e., spinalization) in 12 adult decerebrate cats. Seven cats were spinalized and allowed to recover for 1 mo (i.e., chronic spinal state), whereas 5 cats were evaluated before (i.e., intact state) and after acute spinalization (i.e., acute spinal state). Stretch reflexes were evoked by stretching the left triceps surae (TS) muscles. The force evoked by TS muscles was recorded along with the activity of several hindlimb muscles. Stretch reflexes were abolished in the acute spinal state due to an inability to activate TS muscles, such as soleus (Sol) and lateral gastrocnemius (LG). In chronic spinal cats, reflex force had partly recovered but Sol and LG activity remained considerably depressed, despite the fact that injecting clonidine could recruit these muscles during locomotor-like activity. In contrast, other muscles not recruited in the intact state, most notably semitendinosus and sartorius, were strongly activated by stretching TS muscles in chronic spinal cats. Therefore, stretch reflex pathways from TS muscles to multiple hindlimb muscles undergo functional reorganization following spinalization, both acute and chronic. Altered activation patterns by stretch reflex pathways could explain some sensorimotor deficits observed during locomotion and postural corrections after SCI.

  19. CURRENT CONCEPTS IN MUSCLE STRETCHING FOR EXERCISE AND REHABILITATION

    PubMed Central

    2012-01-01

    Stretching is a common activity used by athletes, older adults, rehabilitation patients, and anyone participating in a fitness program. While the benefits of stretching are known, controversy remains about the best type of stretching for a particular goal or outcome. The purpose of this clinical commentary is to discuss the current concepts of muscle stretching interventions and summarize the evidence related to stretching as used in both exercise and rehabilitation. PMID:22319684

  20. Magnetohydrodynamics flow of a nanofluid driven by a stretching/shrinking sheet with suction.

    PubMed

    Mahabaleshwar, U S; Vinay Kumar, P N; Sheremet, Mikhail

    2016-01-01

    The present paper investigates the effect of a mathematical model describing the aforementioned process in which the ambient nanofluid in the presence of suction/injection and magnetic field are taken into consideration. The flow is induced by an infinite elastic sheet which is stretched along its own plane. The stretching/shrinking of the sheet is assumed to be proportional to the distance from the slit. The governing equations are reduced to a nonlinear ordinary differential equation by means of similarity transformation. The consequential nonlinear equation is solved analytically. Consequences show that the flow field can be divided into a near-field region and a far-field region. Suction on the surface plays an important role in the flow development in the near-field whereas the far-field is responsible mainly by stretching. The electromagnetic effect plays exactly the same role as the MHD, which is to reduce the horizontal flow resulting from stretching. It is shown that the behavior of the fluid flow changes with the change of the nanoparticles type. The present study throws light on the analytical solution of a class of laminar boundary layer equations arising in the stretching/shrinking sheet problem.

  1. Stretched arc discharge in produced water.

    PubMed

    Cho, Y I; Wright, K C; Kim, H S; Cho, D J; Rabinovich, A; Fridman, A

    2015-01-01

    The objective of the present study was to investigate the feasibility of stretching an arc discharge in produced water to increase the volume of produced water treated by plasma. Produced water is the wastewater generated by hydraulic fracturing of shale during the production phase in shale-oil or shale-gas exploration. The electric conductivity of produced water is in the range of 50-200 mS/cm, which provides both a challenge and opportunity for the application of plasmas. Stretching of an arc discharge in produced water was accomplished using a ground electrode and two high-voltage electrodes: one positioned close to the ground electrode and the other positioned farther away from the ground. The benefit of stretching the arc is that the contact between the arc and water is significantly increased, resulting in more efficient plasma treatment in both performance and energy cost.

  2. Optical Data Compression in Time Stretch Imaging

    PubMed Central

    Chen, Claire Lifan; Mahjoubfar, Ata; Jalali, Bahram

    2015-01-01

    Time stretch imaging offers real-time image acquisition at millions of frames per second and subnanosecond shutter speed, and has enabled detection of rare cancer cells in blood with record throughput and specificity. An unintended consequence of high throughput image acquisition is the massive amount of digital data generated by the instrument. Here we report the first experimental demonstration of real-time optical image compression applied to time stretch imaging. By exploiting the sparsity of the image, we reduce the number of samples and the amount of data generated by the time stretch camera in our proof-of-concept experiments by about three times. Optical data compression addresses the big data predicament in such systems. PMID:25906244

  3. Overextended sarcomeres regain filament overlap following stretch.

    PubMed

    Panchangam, Appaji; Herzog, Walter

    2012-09-21

    Sarcomere overextension has been widely implicated in stretch-induced muscle injury. Yet, sarcomere overextensions are typically inferred based on indirect evidence obtained in muscle and fibre preparations, where individual sarcomeres cannot be observed during dynamic contractions. Therefore, it remains unclear whether sarcomere overextensions are permanent following injury-inducing stretch-shortening cycles, and thus, if they can explain stretch-induced force loss. We tested the hypothesis that overextended sarcomeres can regain filament overlap in isolated myofibrils from rabbit psoas muscles. Maximally activated myofibrils (n=13) were stretched from an average sarcomere length of 2.6±0.04μm by 0.9μm sarcomere(-1) at a speed of 0.1μm sarcomere(-1)s(-1) and immediately returned to the starting lengths at the same speed (sarcomere strain=34.1±2.3%). Myofibrils were then allowed to contract isometrically at the starting lengths (2.6μm) for ∼30s before relaxing. Force and individual sarcomere lengths were measured continuously. Out of the 182 sarcomeres, 35 sarcomeres were overextended at the peak of stretch, out of which 26 regained filament overlap in the shortening phase while 9 (∼5%) remained overextended. About 35% of the sarcomeres with initial lengths on the descending limb of the force-length relationship and ∼2% of the sarcomeres with shorter initial lengths were overextended. These findings provide first ever direct evidence that overextended sarcomeres can regain filament overlap in the shortening phase following stretch, and that the likelihood of overextension is higher for sarcomeres residing initially on the descending limb.

  4. Numerical analysis of the rescaling method for parabolic problems with blow-up in finite time

    NASA Astrophysics Data System (ADS)

    Nguyen, V. T.

    2017-01-01

    In this work, we study the numerical solution for parabolic equations whose solutions have a common property of blowing up in finite time and the equations are invariant under the following scaling transformation

  5. Blow-up in p-Laplacian heat equations with nonlinear boundary conditions

    NASA Astrophysics Data System (ADS)

    Ding, Juntang; Shen, Xuhui

    2016-10-01

    In this paper, we investigate the blow-up of solutions to the following p-Laplacian heat equations with nonlinear boundary conditions: {l@{quad}l}(h(u))_t =nabla\\cdot(|nabla u|pnabla u)+k(t)f(u) &{in } Ω×(0,t^{*}), |nabla u|ppartial u/partial n=g(u) &on partialΩ×(0,t^{*}), u(x,0)=u0(x) ≥ 0 & {in } overline{Ω},. where {p ≥ 0} and {Ω} is a bounded convex domain in {RN}, {N ≥ 2} with smooth boundary {partialΩ}. By constructing suitable auxiliary functions and using a first-order differential inequality technique, we establish the conditions on the nonlinearities and data to ensure that the solution u( x, t) blows up at some finite time. Moreover, the upper and lower bounds for the blow-up time, when blow-up does occur, are obtained.

  6. A molecular key for the identification of blow flies in southeastern Nebraska.

    PubMed

    Samarakoon, Upeka; Skoda, Steven R; Baxendale, Frederick P; Foster, John E

    2013-01-01

    Immature blow flies (Calliphoridae) are typically the first colonizers of cadavers. Identification of the early instars using traditional, morphology-based keys is difficult because of their small size, similarity, and simplicity in external morphology. Information derived from molecular genetic data would augment the accurate identification of immature flies. Nine species of blow flies commonly found in southeastern Nebraska were used to examine the utility of molecular-based keys. Polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) were investigated with 10 common, inexpensive, restriction enzymes from an amplicon of approximately 1500 bp spanning the mitochondrial cytochrome oxidase I gene. A simple molecular taxonomic key, comprising RFLP from the restriction enzymes HinfI and DraI, enabled the differentiation of all species used. Further development of PCR-RFLP, including more extensive and intensive examination of blow flies, would benefit forensic laboratories in the accurate identification of evidence consisting of immature blow flies.

  7. Asymptotic blow-up analysis for singular Liouville type equations with applications

    NASA Astrophysics Data System (ADS)

    Bartolucci, D.; Tarantello, G.

    2017-04-01

    We generalize the pointwise estimates obtained in [2,19] and [34] concerning blow-up solutions of the Liouville type equation: Next, we refine our blow up analysis to cover a class of planar Liouville type problems (see (1.27)-(1.28) below) arising from the study of Cosmic Strings (cfr. [28,35]). In this context, we are able to distinguish between a single blow-up radial profile and the case of multiple blow-up profiles, typical of non radial solutions. As a consequence we obtain a (radial) symmetry result which is interesting in itself but also contributes towards the "sharp" solvability issue for the planar problem (1.27)-(1.28).

  8. Towards improving efficiency of control for blowing into a boundary layer through a permeable wall

    NASA Astrophysics Data System (ADS)

    Fomin, V. M.; Kornilov, V. I.; Boiko, A. V.

    2016-08-01

    The results of experimental and numerical investigations of the efficiency of control by an incompressible turbulent boundary layer with the help air blowing through a permeable wall fabricated with maintenance of most of the necessary requirements for the quality and configuration of microapertures and having a low effective roughness are analyzed. Various cases of modeling the process of air blowing into the boundary layer through a specified hi-tech finely perforated surface are considered, and the data for average parameters and characteristics of turbulence of the flow types under investigation are presented. A substantial decrease in the skin-friction coefficient along the model length, which can achieve 90% with increasing the blowing coefficient, is shown. The estimate of the energy consumption for the process of blowing under terrestrial conditions testifies to the high potential of this method of control capable to provide 4-5% gain in the total aerodynamic drag of a simple modeling configuration.

  9. Certolizumab Injection

    MedlinePlus

    ... has not improved when treated with other medications, rheumatoid arthritis (a condition in which the body attacks its ... continues. When certolizumab injection is used to treat rheumatoid arthritis, it is usually given every other week and ...

  10. Natalizumab Injection

    MedlinePlus

    ... prevent episodes of symptoms in people who have Crohn's disease (a condition in which the body attacks the ... If you are receiving natalizumab injection to treat Crohn's disease, your symptoms should improve during the first few ...

  11. Vedolizumab Injection

    MedlinePlus

    ... injection may cause serious allergic reactions during an infusion and for several hours afterward. A doctor or ... of the following symptoms during or after your infusion: rash; itching; swelling of the face, eyes, mouth, ...

  12. Panitumumab Injection

    MedlinePlus

    ... as a solution (liquid) to be given by infusion (injected into a vein). It is usually given ... doctor or nurse in a doctor's office or infusion center. Panitumumab is usually given once every 2 ...

  13. Methotrexate Injection

    MedlinePlus

    ... woman's uterus while she is pregnant), breast cancer, lung cancer, certain cancers of the head and neck; certain ... Methotrexate injection is also used along with rest, physical therapy and ... treat rheumatoid arthritis by decreasing the activity of the immune system.

  14. Alirocumab Injection

    MedlinePlus

    ... injection is used along with diet and certain cholesterol-lowering medications (HMG-CoA reductase inhibitors [statins]) in ... familial heterozygous hypercholesterolemia (an inherited condition in which cholesterol cannot be removed from the body normally) or ...

  15. Evolocumab Injection

    MedlinePlus

    ... injection is used along with diet and certain cholesterol-lowering medications, HMG-CoA reductase inhibitors (statins), in ... heterozygous hypercholesterolemia (HeFH; an inherited condition in which cholesterol cannot be removed from the body normally) or ...

  16. Pentamidine Injection

    MedlinePlus

    Pentamidine injection is used to treat pneumonia caused by a fungus called Pneumocystis carinii. It is in a class of medications called antiprotozoals. It works by stopping the growth of protozoa that can cause pneumonia.

  17. Oxytocin Injection

    MedlinePlus

    Oxytocin injection is used to begin or improve contractions during labor. Oxytocin also is used to reduce bleeding after childbirth. ... other medications or procedures to end a pregnancy. Oxytocin is in a class of medications called oxytocic ...

  18. Ibritumomab Injection

    MedlinePlus

    ... is in a class of medications called monoclonal antibodies with radioisotopes. It works by attaching to cancer ... you receive ibritumomab injection, your body may develop antibodies (substances in the blood that help the immune ...

  19. Ganciclovir Injection

    MedlinePlus

    ... problems, eye problems other than CMV retinitis, or kidney disease.tell your doctor if you are pregnant or plan to become pregnant. Ganciclovir injection may cause infertility (difficulty becoming pregnant). However, if you are a ...

  20. Bendamustine Injection

    MedlinePlus

    ... a type of cancer of the white blood cells). Bendamustine injection is also used to treat a ... that begins in a type of white blood cell that normally fights infection) that is slow spreading, ...

  1. Vancomycin Injection

    MedlinePlus

    ... medications called glycopeptide antibiotics. It works by killing bacteria that cause infections.Antibiotics such as vancomycin injection ... infection may not be completely treated and the bacteria may become resistant to antibiotics.

  2. Levofloxacin Injection

    MedlinePlus

    ... of antibiotics called fluoroquinolones. It works by killing bacteria that cause infections.Antibiotics such as levofloxacin injection ... infection may not be completely treated and the bacteria may become resistant to antibiotics.

  3. Doxycycline Injection

    MedlinePlus

    ... medications called tetracycline antibiotics. It works by killing bacteria that cause infections.Antibiotics such as doxycycline injection ... infection may not be completely treated and the bacteria may become resistant to antibiotics.

  4. Sumatriptan Injection

    MedlinePlus

    ... accompanied by nausea and sensitivity to sound and light). Sumatriptan injection is also used to treat the ... children. Store it at room temperature, away from light, excess heat, and moisture (not in the bathroom). ...

  5. Alemtuzumab Injection

    MedlinePlus

    ... injection, the medication is usually given three times weekly on alternate days (usually Monday, Wednesday, and Friday) ... that you eat foods that are rich in iron such as meats, leafy green vegetables, and fortified ...

  6. Epinephrine Injection

    MedlinePlus

    Epinephrine injection is used along with emergency medical treatment to treat life-threatening allergic reactions caused by ... or stings, foods, medications, latex, and other causes. Epinephrine is in a class of medications called alpha- ...

  7. Mitoxantrone Injection

    MedlinePlus

    ... medications to relieve pain in people with advanced prostate cancer who did not respond to other medications. Mitoxantrone ... doses). When mitoxantrone injection is used to treat prostate cancer, it is usually given once every 21 days. ...

  8. Trastuzumab Injection

    MedlinePlus

    ... with other medications to treat certain types of stomach cancer that have spread to other parts of the ... weeks. When trastuzumab injection is used to treat stomach cancer, it is usually given once every 3 weeks. ...

  9. Topotecan Injection

    MedlinePlus

    ... organs where eggs are formed) and small cell lung cancer (a type of cancer that begins in the ... topotecan injection is used to treat ovarian or lung cancer, it is usually given once a day for ...

  10. Palonosetron Injection

    MedlinePlus

    ... that may occur several days after receiving certain chemotherapy medications. Palonosetron injection is in a class of medications called 5-HT3 receptor antagonists. It works by blocking the action of serotonin, a natural ...

  11. Meropenem Injection

    MedlinePlus

    ... skin and abdominal (stomach area) infections caused by bacteria and meningitis (infection of the membranes that surround ... of medications called antibiotics. It works by killing bacteria that cause infection.Antibiotics such as meropenem injection ...

  12. Amikacin Injection

    MedlinePlus

    ... treat certain serious infections that are caused by bacteria such as meningitis (infection of the membranes that ... medications called aminoglycoside antibiotics. It works by killing bacteria.Antibiotics such as amikacin injection will not work ...

  13. Ertapenem Injection

    MedlinePlus

    ... abdominal (stomach area) infections, that are caused by bacteria. It is also used for the prevention of ... medications called carbapenem antibiotics. It works by killing bacteria.Antibiotics such as ertapenem injection will not work ...

  14. Moxifloxacin Injection

    MedlinePlus

    ... is used to treat certain infections caused by bacteria such as pneumonia; ; and , skin, and abdominal (stomach ... antibiotics called fluoroquinolones. It works by killing the bacteria that cause infections.Antibiotics such as moxifloxacin injection ...

  15. Cefepime Injection

    MedlinePlus

    ... is used to treat certain infections caused by bacteria including pneumonia, and skin, urinary tract, and kidney ... medications called cephalosporin antibiotics. It works by killing bacteria.Antibiotics such as cefepime injection will not work ...

  16. Cefazolin Injection

    MedlinePlus

    ... is used to treat certain infections caused by bacteria including skin, bone, joint, genital, blood, heart valve, ... medications called cephalosporin antibiotics. It works by killing bacteria.Antibiotics such as cefazolin injection will not work ...

  17. Daptomycin Injection

    MedlinePlus

    ... blood infections or serious skin infections caused by bacteria. Daptomycin injection is in a class of medications called cyclic lipopeptide antibiotics. It works by killing bacteria. Antibiotics will not work for treating colds, flu, ...

  18. Aztreonam Injection

    MedlinePlus

    ... to treat certain infections that are caused by bacteria, including respiratory tract (including pneumonia and bronchitis), urinary ... abdominal (stomach area) infections, that are caused by bacteria. Aztreonam injection also may be used before, during, ...

  19. Ceftazidime Injection

    MedlinePlus

    ... is used to treat certain infections caused by bacteria including pneumonia and other lower respiratory tract (lung) ... medications called cephalosporin antibiotics. It works by killing bacteria.Antibiotics such as ceftazidime injection will not work ...

  20. Tobramycin Injection

    MedlinePlus

    ... treat certain serious infections that are caused by bacteria such as meningitis (infection of the membranes that ... medications called aminoglycoside antibiotics. It works by killing bacteria.Antibiotics such as tobramycin injection will not work ...

  1. Ciprofloxacin Injection

    MedlinePlus

    ... is used to treat certain infections caused by bacteria such as pneumonia; and infections of the skin, ... of antibiotics called fluoroquinolones. It works by killing bacteria that cause infections.Antibiotics such as ciprofloxacin injection ...

  2. Gentamicin Injection

    MedlinePlus

    ... treat certain serious infections that are caused by bacteria such as meningitis (infection of the membranes that ... medications called aminoglycoside antibiotics. It works by killing bacteria.Antibiotics such as gentamicin injection will not work ...

  3. Ceftaroline Injection

    MedlinePlus

    ... infections and pneumonia (lung infection) caused by certain bacteria. Ceftaroline is in a class of medications called cephalosporin antibiotics. It works by killing bacteria.Antibiotics such as ceftaroline injection will not work ...

  4. Daclizumab Injection

    MedlinePlus

    ... course of disease where symptoms flare up from time to time) of multiple sclerosis (MS; a disease in which ... injections. Before you use daclizumab yourself the first time, read the written instructions that come with it. ...

  5. Risperidone Injection

    MedlinePlus

    ... release (long-acting) injection is used to treat schizophrenia (a mental illness that causes disturbed or unusual ... do not already have diabetes. If you have schizophrenia, you are more likely to develop diabetes than ...

  6. Acyclovir Injection

    MedlinePlus

    ... chickenpox in the past) in people with weak immune systems. It is also used to treat first-time ... from time to time) in people with normal immune systems. Acyclovir injection is used to treat herpes simplex ...

  7. Omalizumab Injection

    MedlinePlus

    ... steroids. Omalizumab is also used to treat chronic hives without a known cause that cannot successfully be ... is not used to treat other forms of hives or allergic conditions. Omalizumab injection is in a ...

  8. Pegloticase Injection

    MedlinePlus

    ... doctor if you have glucose-6-phosphate dehydrogenase (G6PD) deficiency (an inherited blood disease). Your doctor may test you for G6PD deficiency before you start to receive pegloticase injection. If ...

  9. Lacosamide Injection

    MedlinePlus

    ... with other medications to control certain types of seizures in people who cannot take oral medications. Lacosamide ... If you suddenly stop using lacosamide injection, your seizures may happen more often. Your doctor will probably ...

  10. Oxacillin Injection

    MedlinePlus

    ... injection is in a class of medications called penicillins. It works by killing bacteria.Antibiotics such as ... and pharmacist if you are allergic to oxacillin; penicillins; cephalosporin antibiotics such as cefaclor, cefadroxil, cefazolin, cefdinir, ...

  11. Nafcillin Injection

    MedlinePlus

    ... injection is in a class of medications called penicillins. It works by killing bacteria.Antibiotics such as ... and pharmacist if you are allergic to nafcillin; penicillins; cephalosporin antibiotics such as cefaclor, cefadroxil, cefazolin, cefdinir, ...

  12. Ampicillin Injection

    MedlinePlus

    ... injection is in a class of medications called penicillins. It works by killing bacteria.Antibiotics such as ... and pharmacist if you are allergic to ampicillin; penicillins; cephalosporin antibiotics such as cefaclor, cefadroxil, cefazolin (Ancef, ...

  13. Naloxone Injection

    MedlinePlus

    ... emergency medical treatment to reverse the life-threatening effects of a known or suspected opiate (narcotic) overdose. ... is also used after surgery to reverse the effects of opiates given during surgery. Naloxone injection is ...

  14. Omacetaxine Injection

    MedlinePlus

    ... or cannot take these medications due to side effects. Omacetaxine injection is in a class of medications ... a treatment cycle if you experience serious side effects of the medication or if blood tests show ...

  15. Methylnaltrexone Injection

    MedlinePlus

    ... injection is used to treat constipation caused by opioid (narcotic) pain medications in patients with chronic (on-going) pain that is not caused by ... by protecting the bowel from the effects of opioid (narcotic) medications.

  16. Denosumab Injection

    MedlinePlus

    ... menstrual periods), who have an increased risk for fractures (broken bones) or who cannot take or did ... receiving certain treatments that increase their risk for fractures. Denosumab injection (Xgeva) is used to reduce fractures ...

  17. Rasburicase Injection

    MedlinePlus

    ... break down) in people with certain types of cancer who are being treated with chemotherapy medications. Rasburicase injection is in a class of medications called enzymes. It works by breaking down uric acid so that the body can eliminate it.

  18. Gemcitabine Injection

    MedlinePlus

    ... with surgery. Gemcitabine is also used to treat cancer of the pancreas that has spread to other parts of the ... 4 weeks. When gemcitabine is used to treat cancer of pancreas it may be injected once every week. The ...

  19. Doxercalciferol Injection

    MedlinePlus

    Doxercalciferol injection is used to treat secondary hyperparathyroidism (a condition in which the body produces too much parathyroid hormone [PTH; a natural substance needed to control the amount of calcium in ...

  20. Granisetron Injection

    MedlinePlus

    ... that may occur after surgery. Granisetron extended-release (long-acting) injection is used with other medications to prevent nausea and vomiting caused by cancer chemotherapy that may occur immediately ...

  1. Fluconazole Injection

    MedlinePlus

    ... injection is used to treat fungal infections, including yeast infections of the mouth, throat, esophagus (tube leading ... by fungus. Fluconazole is also used to prevent yeast infections in patients who are likely to become ...

  2. Docetaxel Injection

    MedlinePlus

    ... allergic to docetaxel injection or drugs made with polysorbate 80, an ingredient found in some medications. Ask ... if a medication you are allergic to contains polysorbate 80. If you experience any of the following ...

  3. Haloperidol Injection

    MedlinePlus

    ... emotions). Haloperidol injection is also used to control motor tics (uncontrollable need to repeat certain body movements) ... people who have Tourette's disorder (condition characterized by motor or verbal tics). Haloperidol is in a class ...

  4. Operation and results of the Eindhoven MHD blow-down facility

    SciTech Connect

    Balemans, W.J.M.; Massee, P. )

    1991-01-01

    In this paper experience with the Eindhoven MHD blow-down facility is described. Attention is focused especially on the main components of the blow-down facility, on the conditions necessary for optimum MHD operation and on the results obtained. The static pressure distributions indicate that the maximum enthalpy extraction (12.9%) was obtained in the present hot flow train. For a further increase of enthalpy extraction, a modification of the hot flow train would be necessary.

  5. Effect of Drawing on Structure and Properties of Copolyamide Nanocomposites by Film Blowing

    NASA Astrophysics Data System (ADS)

    Russo, G. M.; Garofalo, E.; Incarnato, L.

    2008-08-01

    The aim of the present work is to analyze bubble stability in the film blowing processing of copolyamide based nanocomposites and to investigate the effect of uniaxial film drawing on nanostructure and final properties. Nanocomposite films with different loadings of nanoclay were produced by film blowing equipment and collected at different draw ratios. Oxygen barrier and mechanical properties of the films were investigated and correlated to the resulting nanomorphology and polymer crystal structures.

  6. Blowing dust and highway safety in the southwestern US

    NASA Astrophysics Data System (ADS)

    Li, Junran; Lee, Jeff; Gill, Thomas

    2015-04-01

    Windblown dust poses a significant hazard to highway safety. In the southwestern US, dust related chain-reaction traffic accidents occurred every year, however, no known studies have specifically investigated this issue in this area. Remote sensing and field observations reveal that wind erosion in this region typically occurs in localized source areas, characterized as "hot spots", while most of the landscape does not erode. However, the spatial and temporal patterns of the hot spots and their relations to the occurrence of blowing dust to the highways are poorly understood. The lack of this critical information hinders highway managers to make informed and timely management decisions when wind events strike. Projected global changes, including changes in climate, land use, and land cover, will likely bring more frequent and extreme dust emissions to the southwestern US, including a majority of the Southern Plains, posing a serious threat to transportation safety in this region in the coming decades. Our preliminary investigation in west Texas indicated that a majority of the sources that contribute dust to the highways are located on sandy surface within a few kilometers of the highways and more than half of them are from cultivated cropland.

  7. Generating Soap Bubbles by Blowing on Soap Films.

    PubMed

    Salkin, Louis; Schmit, Alexandre; Panizza, Pascal; Courbin, Laurent

    2016-02-19

    Making soap bubbles by blowing air on a soap film is an enjoyable activity, yet a poorly understood phenomenon. Working either with circular bubble wands or long-lived vertical soap films having an adjustable steady state thickness, we investigate the formation of such bubbles when a gas is blown through a nozzle onto a film. We vary film size, nozzle radius, space between the film and nozzle, and gas density, and we measure the gas velocity threshold above which bubbles are formed. The response is sensitive to containment, i.e., the ratio between film and jet sizes, and dissipation in the turbulent gas jet, which is a function of the distance from the film to the nozzle. We rationalize the observed four different regimes by comparing the dynamic pressure exerted by the jet on the film and the Laplace pressure needed to create the curved surface of a bubble. This simple model allows us to account for the interplay between hydrodynamic, physicochemical, and geometrical factors.

  8. Sorption of antimicrobial agents in blow-fill-seal packs.

    PubMed

    Amin, Aeshna; Chauhan, Sateesh; Dare, Manish; Bansal, Arvind Kumar

    2012-01-01

    The present work studies the interaction of methyl paraben (MPB) and propyl paraben (PPB), two widely used antimicrobial agents in multi-dose ophthalmic formulations, with 5 mL, low density polyethylene (LDPE) and polypropylene (PP) blow-fill-seal (BFS) packs, by subjecting the systems to accelerated stability conditions of 40°C/25% RH. The effect of pH, paraben concentration, and relative humidity (RH) on the sorption loss of both the parabens was studied. Additionally, the effects of buffer species and buffer strength on MPB sorption were studied. LDPE packs showed significantly higher loss compared to PP packs which showed < 5% loss in all cases. PPB showed a significantly higher loss (40-50%) than MPB (9-16%) in LDPE. pH (3.0, 5.0, 7.0) did not have a statistically significant effect on sorption. However, concentration, humidity and buffer at pH 7 affected paraben sorption. The application of the power law suggested that the MPB followed non-Fickian diffusion while PPB showed non-Fickian to Case II diffusion in LDPE packs. In conclusion, caution should be exercised while using parabens in LDPE BFS packs because substantial losses of the antimicrobial agent during the shelf-life can compromise the preservative effectiveness against 'in-use' contamination.

  9. High speed aerodynamics of upper surface blowing aircraft configurations

    NASA Technical Reports Server (NTRS)

    Birckelbaw, Larry D.

    1992-01-01

    An experimental investigation of the high speed aerodynamics of Upper Surface Blowing (USB) aircraft configurations has been conducted to accurately define the magnitude and causes of the powered configuration cruise drag. A highly instrumented wind tunnel model of a realistic USB configuration was used which permitted parametric variations in the number and spanwise location of the nacelles and was powered with two turbofan engine simulators. The tests conducted in the Ames 14 Foot Transonic Wind Tunnel examined 10 different configurations at Mach numbers from 0.5 to 0.775, fan nozzle pressure ratios from 1.1 to 2.1 and angles of attack from -4 to 6 degrees. Measured force data is presented which indicates the cruise drag penalty associated with each configuration and surface pressure contour plots are used to illustrate the underlying flowfield physics. It was found that all of the tested configurations suffered from a severe drag penalty which increased with freestream Mach number, power setting and angle of attack and was associated with the presence of strong shocks and regions of separated flow in the wing/nacelle junction regions.

  10. Action of Ants on Vertebrate Carcasses and Blow Flies (Calliphoridae).

    PubMed

    Paula, Michele C; Morishita, Gustavo M; Cavarson, Carolina H; Gonçalves, Cristiano R; Tavares, Paulo R A; Mendonça, Angélica; Súarez, Yzel R; Antonialli-Junior, William F

    2016-11-01

    Forensic entomology is a science that uses insect fauna as a tool to assist in criminal investigations and civil proceedings. Although the most researched insects are the Diptera and Coleoptera, ants may be present in all stages of decomposition. The aim of this study was to evaluate the role of ants and their action on blow flies during the decomposition process. Experiments were performed in which four pig carcasses were exposed in the cold and dry season (November/2012 and March/2013) and four in the hot and wet season (May/2013 and August/2013). Flies were the first insects to detect and interact with the carcasses, and six species of the Calliphoridae family were identified. Ants (Hymenoptera: Formicidae) were the second group, with six subfamilies identified. Myrmycinae represented 42% of the species, followed by Formicinae (28%), Ectatominae and Ponerinae (both 10%), and Ecitoninae and Dolichoderinae (both 5%). The ants acted on the carcasses as predators of visiting species, omnivores, and necrophagous, in all cases significantly affecting the decomposition time, slowing it down when the ants preyed on adult and immature insects consuming the carcass, or accelerating it by consuming the carcass and creating holes that could serve as gateways for the action of other organisms. The ants also generated artifacts that could lead to forensic misinterpretation.

  11. Generating Soap Bubbles by Blowing on Soap Films

    NASA Astrophysics Data System (ADS)

    Salkin, Louis; Schmit, Alexandre; Panizza, Pascal; Courbin, Laurent

    2016-02-01

    Making soap bubbles by blowing air on a soap film is an enjoyable activity, yet a poorly understood phenomenon. Working either with circular bubble wands or long-lived vertical soap films having an adjustable steady state thickness, we investigate the formation of such bubbles when a gas is blown through a nozzle onto a film. We vary film size, nozzle radius, space between the film and nozzle, and gas density, and we measure the gas velocity threshold above which bubbles are formed. The response is sensitive to containment, i.e., the ratio between film and jet sizes, and dissipation in the turbulent gas jet, which is a function of the distance from the film to the nozzle. We rationalize the observed four different regimes by comparing the dynamic pressure exerted by the jet on the film and the Laplace pressure needed to create the curved surface of a bubble. This simple model allows us to account for the interplay between hydrodynamic, physicochemical, and geometrical factors.

  12. Landauer's blow-torch effect in systems with entropic potential

    NASA Astrophysics Data System (ADS)

    Das, Moupriya; Ray, Deb Shankar

    2015-11-01

    We consider local heating of a part of a two-dimensional bilobal enclosure of a varying cross section confining a system of overdamped Brownian particles. Since varying cross section in higher dimension results in an entropic potential in lower dimension, local heating alters the relative stability of the entropic states. We show that this blow-torch effect modifies the entropic potential in a significant way so that the resultant effective entropic potential carries both the features of variation of width of the confinement and variation of temperature along the direction of transport. The reduced probability distribution along the direction of transport calculated by full numerical simulations in two dimensions agrees well with our analytical findings. The extent of population transfer in the steady state quantified in terms of the integrated probability of residence of the particles in either of the two lobes exhibits interesting variation with the mean position of the heated region. Our study reveals that heating around two particular zones of a given lobe maximizes population transfer to the other.

  13. Injection overview

    SciTech Connect

    Prestwich, S.

    1983-12-01

    The test program was initiated at the Raft River Geothermal Field in southern Idaho in September 1982. A series of eight short-term injection and backflow tests, followed by a long-term injection test, were conducted on one well in the field. Tracers were added during injection and monitored during backflow as well. The principal objective was to determine if tracers could be effectively used as a means to assess reservoir characteristics in a one-well test. The test program resulted in a unique data set which shows promise as a means to improve understanding of the reservoir characteristics. In December 1982, an RFP was issued to obtain an industrial partner to obtain follow-on data on the injection/backflow technique in a second field, and to study any alternate advanced concepts for injection testing which the industrial community might recommend. The East Mesa Geothermal Field was selected for the second test series. Two wells were utilized for testing, and a series of ten tests were conducted in July and August 1983, aimed principally at further evaluation of the injection/backflow technique.

  14. Lean Blow-out Studies in a Swirl Stabilized Annular Gas Turbine Combustor

    NASA Astrophysics Data System (ADS)

    Mishra, R. K.; Kishore Kumar, S.; Chandel, Sunil

    2015-05-01

    Lean blow out characteristics in a swirl stabilized aero gas turbine combustor have been studied using computational fluid dynamics. For CFD analysis, a 22.5° sector of an annular combustor is modeled using unstructured tetrahedral meshes comprising 1.2 × 106 elements. The governing equations are solved using the eddy dissipation combustion model in CFX. The primary combustion zone is analyzed by considering it as a well stirred reactor. The analysis has been carried out for different operating conditions of the reactants entering into the control volume. The results are treated as the base-line or reference values. Combustion lean blow-out limits are further characterized studying the behavior of combustion zone during transient engine operation. The validity of the computational study has been established by experimental study on a full-scale annular combustor in an air flow test facility that is capable of simulating different conditions at combustor inlet. The experimental result is in a good agreement with the analytical predictions. Upon increasing the combustor mass flow, the lean blow out limit increases, i.e., the blow out occurs at higher fuel-air ratios. In addition, when the operating pressure decreases, the lean blow out limit increases, i.e., blow out occurs at higher fuel-air ratios.

  15. Occurrence of blow fly species (Diptera: calliphoridae) in Phitsanulok Province, Northern Thailand.

    PubMed

    Bunchu, Nophawan; Sukontason, Kom; Sanit, Sangob; Chidburee, Polprecha; Kurahashi, Hiromu; Sukontason, Kabkaew L

    2012-12-01

    Based on the current forensic importance of blow flies (Diptera: Calliphoridae), their biological aspects have been studied increasingly worldwide. The blow fly fauna in Phitsanulok Province, Northern Thailand was studied from May 2009 to April 2010 in the residential, agricultural, mountainous and forested areas of Muang, Wat Bot, Nakhon Thai and Wang Thong districts, respectively, in order to know the occurrence of blow flies in this province. Collections were carried out monthly using commercial funnel fly traps and sweeping methods, with 1-day tainted pork viscera as bait. Identification of adult blow flies exhibited 14 634 specimens, comprising of 5 subfamilies, 14 genera and 36 species. Chrysomya megacephala (Fabricius, 1794) and Achoetandrus rufifacies (Macquart, 1843) were the most and second most abundant species trapped, respectively. These two species of carrion flies prevailed in all the types of land investigated. We calculated and compared the diversity indices, species evenness and richness, and similarity coefficients of the blow fly species in various areas. The data from this study may be used to identify the potential of forensicallyimportant fly species within Phitsanulok Province and fulfill the information on blow fly fauna in Thailand.

  16. Fledging success is a poor indicator of the effects of bird blow flies on ovenbird survival

    USGS Publications Warehouse

    Peterson, Sean M.; Streby, Henry M.; Kapfer, Paul M.

    2009-01-01

    Infestations of bird blow flies (Protocalliphora spp. and Trypocalliphora braueri) have various negative effects on the condition of nestling birds. In the absence of other stressors such as inclement weather, however, infestation alone rarely reduces fledging success. Previous studies have documented effects of blow flies on nestling condition and fledging success. Without information regarding fledgling survival, the full effect of blow-fly infestation remains unclear. To fully investigate the effect of blow-fly infestation on reproductive success of the Ovenbird (Seiurus aurocapilla), we monitored infested and non-infested nests and monitored fledglings from each by using radio telemetry. Blow flies did not affect birds during the nestling period, as brood size, mean nestling mass, fledging success, and time to fledging in infested and non-infested nests were no different. Fledgling survival and minimum distance traveled the first day after fledging, however, were significantly lower for infected fledglings than for those that were not infected. We conclude that the stress of the early fledgling period combined with recent or concurrent blow-fly infection increases mortality in young Oven-birds. Our results demonstrate the importance of including the post-fledging period in investigations of the effects of ectoparasitic infestations on birds.

  17. First Satellite-detected Perturbations of Outgoing Longwave Radiation Associated with Blowing Snow Events over Antarctica

    NASA Technical Reports Server (NTRS)

    Yang, Yuekui; Palm, Stephen P.; Marshak, Alexander; Wu, Dong L.; Yu, Hongbin; Fu, Qiang

    2014-01-01

    We present the first satellite-detected perturbations of the outgoing longwave radiation (OLR) associated with blowing snow events over the Antarctic ice sheet using data from Cloud-Aerosol Lidar with Orthogonal Polarization and Clouds and the Earth's Radiant Energy System. Significant cloud-free OLR differences are observed between the clear and blowing snow sky, with the sign andmagnitude depending on season and time of the day. During nighttime, OLRs are usually larger when blowing snow is present; the average difference in OLRs between without and with blowing snow over the East Antarctic Ice Sheet is about 5.2 W/m2 for the winter months of 2009. During daytime, in contrast, the OLR perturbation is usually smaller or even has the opposite sign. The observed seasonal variations and day-night differences in the OLR perturbation are consistent with theoretical calculations of the influence of blowing snow on OLR. Detailed atmospheric profiles are needed to quantify the radiative effect of blowing snow from the satellite observations.

  18. Cloud Network Helps Stretch IT Dollars

    ERIC Educational Resources Information Center

    Collins, Hilton

    2012-01-01

    No matter how many car washes or bake sales schools host to raise money, adding funds to their coffers is a recurring problem. This perpetual financial difficulty makes expansive technology purchases or changes seem like a pipe dream for school CIOs and has education technologists searching for ways to stretch money. In 2005, state K-12 school…

  19. How to determine local stretching and tension in a flow-stretched DNA molecule

    NASA Astrophysics Data System (ADS)

    Pedersen, Jonas N.; Marie, Rodolphe; Kristensen, Anders; Flyvbjerg, Henrik

    2016-04-01

    We determine the nonuniform stretching of and tension in a mega base pairs-long fragment of deoxyribonucleic acid (DNA) that is flow stretched in a nanofluidic chip. We use no markers, do not know the contour length of the DNA, and do not have the full DNA molecule inside our field of view. Instead, we analyze the transverse thermal motion of the DNA. Tension at the center of the DNA adds up to 16 pN, giving almost fully stretched DNA. This method was devised for optical mapping of DNA, specifically, DNA denaturation patterns. It may be useful also for other studies, e.g., DNA-protein interactions, specifically, their tension dependence. Generally, wherever long strands of DNA—e.g., native DNA extracted from human cells or bacteria—must be stretched with ease for inspection, this method applies.

  20. Understanding the bacterial communities of hard cheese with blowing defect.

    PubMed

    Bassi, Daniela; Puglisi, Edoardo; Cocconcelli, Pier Sandro

    2015-12-01

    The environment of hard cheese encourages bacterial synergies and competitions along the ripening process, which might lead in defects such as clostridial blowing. In this study, Denaturing Gradient Gel Electrophoresis (DGGE), a quantitative Clostridium tyrobutyricum PCR and next-generation Illumina-based sequencing of 16S rRNA gene were applied to study 83 Grana Padano spoiled samples. The aim was to investigate the community of clostridia involved in spoilage, the ecological relationships with the other members of the cheese microbiota, and the effect of lysozyme. Three main genera were dominant in the analysed cheeses, Lactobacillus, Streptococcus and Clostridium, and the assignment at the species level was of 94.3% of 4,477,326 high quality sequences. C. tyrobutyricum and C. butyricum were the most prevalent clostridia. Hierarchical clustering based on the abundance of bacterial genera, revealed three main clusters: one characterized by the highest proportion of Clostridium, a second where Lactobacillus was predominant and the last, dominated by Streptococcus thermophilus. Ecological relationships among species were found: cheeses characterized by an high abundance of S. thermophilus and L. rhamnosus were spoiled by C. tyrobutyricum while, when L. delbrueckii was the most abundant Lactobacillus, C. butyricum was the dominant spoiling species. Lysozyme also shaped the bacterial community, reducing C. tyrobutyricum in favour of C. butyricum. Moreover, this preservative increased the proportion of L. delbrueckii and obligate heterofermentative lactobacilli and lowered L. helveticus and non-starter species, such as L. rhamnosus and L. casei.

  1. Computational analysis of forebody tangential slot blowing on the high alpha research vehicle

    NASA Technical Reports Server (NTRS)

    Gee, Ken

    1995-01-01

    A numerical analysis of forebody tangential slot blowing as a means of generating side force and yawing moment is conducted using an aircraft geometry. The Reynolds-averaged, thin-layer, Navier-Stokes equations are solved using a partially flux-split, approximately-factored algorithm. An algebraic turbulence model is used to determine the turbulent eddy viscosity values. Solutions are obtained using both patched and overset grid systems. In the patched grid model, and actuator plane is used to introduce jet variables into the flow field. The overset grid model is used to model the physical slot geometry and facilitate modeling of the full aircraft configuration. A slot optimization study indicates that a short slot located close to the nose of the aircraft provided the most side force and yawing moment per unit blowing coefficient. Comparison of computed surface pressure with that obtained in full-scale wind tunnel tests produce good agreement, indicating the numerical method and grid system used in the study are valid. Full aircraft computations resolve the changes in vortex burst point due to blowing. A time-accurate full-aircraft solution shows the effect of blowing on the changes in the frequency of the aerodynamic loads over the vertical tails. A study of the effects of freestream Mach number and various jet parameters indicates blowing remains effective through the transonic Mach range. An investigation of the force onset time lag associated with forebody blowing shows the lag to be minimal. The knowledge obtained in this study may be applied to the design of a forebody tangential slot blowing system for use on flight aircraft.

  2. Identification of CFC and HCFC substitutes for blowing polyurethane foam insulation products. Report for September 1993-August 1994

    SciTech Connect

    Howard, P.H.; Tunkel, J.L.; Hendriks, R.V.

    1996-04-01

    The paper gives results of a systematic search to identify additional candidates as third-generation blowing agents, chemical compounds that are not stratospheric ozone depleters that can be used as substitutes for chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) blowing agents in rigid polyurethane foam insulating materials. To identify the most promising substitutes, potential third-generation blowing agents were ranked using a methodology developed for this project.

  3. Diagnosing the PEP-II Injection System

    SciTech Connect

    Decker, F.-J.; Donald, M.H.; Iverson, R.H.; Kulikov, A.; Pappas, G.C.; Weaver, M.; /SLAC

    2005-05-09

    The injection of beam into the PEP-II B-Factory, especially into the High Energy Ring (HER) has some challenges. A high background level in the BaBar detector has for a while inhibited us from trickling charge into the HER similar to the Low Energy Ring (LER). Analyzing the injection system has revealed many issues which could be improved. The injection bump between two kickers was not closed, mainly because the phase advance wasn't exactly 180{sup o} and the two kicker strengths were not balanced. Additionally we found reflections which kick the stored beam after the main kick and cause the average luminosity to drop about 3% for a 10 Hz injection rate. The strength of the overall kick is nearly twice as high as the design, indicating a much bigger effective septum thickness. Compared with single beam the background is worse when the HER beam is colliding with the LER beam. This hints that the beam-beam force and the observed vertical blow-up in the HER pushes the beam and especially the injected beam further out to the edge of the dynamic aperture or beyond.

  4. NORTHERLY STRETCH OF MILLBURY PORTION; GENERAL VIEW ACROSS CANAL PRISM ...

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

    NORTHERLY STRETCH OF MILLBURY PORTION; GENERAL VIEW ACROSS CANAL PRISM TO TOWPATH BERM (LATER FILL ENCROACHING LEFT) NEAR CENTER OF THIS STRETCH; VIEW TO SOUTHWEST - Blackstone Canal Worcester-Millbury Segment, Eastern bank of Blackstone River, Millbury, Worcester County, MA

  5. Pegaptanib Injection

    MedlinePlus

    ... if you have or have ever had diabetes, high blood pressure, a heart attack, or a stroke.tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while using pegaptanib injection, ...

  6. Ramucirumab Injection

    MedlinePlus

    ... doctor if you have or have ever had high blood pressure, a wound that has not healed, or liver disease.tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. Ramucirumab injection may harm your unborn baby. You ...

  7. Reslizumab Injection

    MedlinePlus

    ... the infusion or for a short period of time after the infusion has finished.You will receive each injection of reslizumab in a doctor's office or medical facility. You will stay in the office for some time after you receive the medication so your doctor ...

  8. Dexrazoxane Injection

    MedlinePlus

    ... are used to treat or prevent certain side effects that may be caused by chemotherapy medications. Dexrazoxane ... Dexrazoxane injection may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away: pain or swelling in the place ...

  9. Numerical study of blow-up and dispersive shocks in solutions to generalized Korteweg-de Vries equations

    NASA Astrophysics Data System (ADS)

    Klein, C.; Peter, R.

    2015-06-01

    We present a detailed numerical study of solutions to general Korteweg-de Vries equations with critical and supercritical nonlinearity, both in the context of dispersive shocks and blow-up. We study the stability of solitons and show that they are unstable against being radiated away and blow-up. In the L2 critical case, the blow-up mechanism by Martel, Merle and Raphaël can be numerically identified. In the limit of small dispersion, it is shown that a dispersive shock always appears before an eventual blow-up. In the latter case, always the first soliton to appear will blow up. It is shown that the same type of blow-up as for the perturbations of the soliton can be observed which indicates that the theory by Martel, Merle and Raphaël is also applicable to initial data with a mass much larger than the soliton mass. We study the scaling of the blow-up time t∗ in dependence of the small dispersion parameter ɛ and find an exponential dependence t∗(ɛ) and that there is a minimal blow-up time t0∗ greater than the critical time of the corresponding Hopf solution for ɛ → 0. To study the cases with blow-up in detail, we apply the first dynamic rescaling for generalized Korteweg-de Vries equations. This allows to identify the type of the singularity.

  10. Simulation on Decarburization and Inclusion Removal Process in the Ruhrstahl-Heraeus (RH) Process with Ladle Bottom Blowing

    NASA Astrophysics Data System (ADS)

    Geng, Dian-Qiao; Zheng, Jin-Xing; Wang, Kai; Wang, Ping; Liang, Ru-Quan; Liu, Hai-Tao; Lei, Hong; He, Ji-Cheng

    2015-03-01

    To enhance the refining efficiency of the Ruhrstahl-Heraeus (RH) process, the ladle bottom blowing was employed in RH degasser and a numerical method was employed to investigate the decarburization and inclusion removal in RH with ladle bottom blowing. The results showed that the decarburization rate in RH with ladle bottom blowing is greater than that in traditional RH. The larger mass fraction of carbon at the recirculation zone under up snorkel disappears because of the gas bubbles from ladle bottom blowing in an RH degasser. For RH with ladle bottom blowing, the decarburization at argon bubble surface accounts for the majority of the removed carbon, and it is approximately two times greater than that in the inner site of the vacuum chamber. Besides, the inclusion removal rate in RH with ladle bottom blowing is greater than that in traditional RH, and the maximum inclusion characteristic radius is much less in RH with ladle bottom blowing than that in traditional RH. Besides, the accumulation of inclusions in ladle between sidewall and up snorkel and the recirculation zone under up snorkel, which can be found in traditional RH, disappears in RH with ladle bottom blowing. For RH with ladle bottom blowing, the average number density of inclusions decreases more drastically than that in traditional RH and the average terminal number density of inclusions is much smaller than that in traditional RH.

  11. Film cooling effectiveness and heat transfer with injection through holes

    NASA Technical Reports Server (NTRS)

    Eriksen, V. L.

    1971-01-01

    An experimental investigation of the local film cooling effectiveness and heat transfer downstream of injection of air through discrete holes into a turbulent boundary layer of air on a flat plate is reported. Secondary air is injected through a single hole normal to the main flow and through both a single hole and a row of holes spaced at three diameter intervals with an injection angle of 35 deg to the main flow. Two values of the mainstream Reynolds number are used; the blowing rate is varied from 0.1 to 2.0. Photographs of a carbon dioxide-water fog injected into the main flow at an angle of 90 deg are also presented to show interaction between the jet and mainstream.

  12. Vibrational overtone stretching transitions in sarin

    NASA Astrophysics Data System (ADS)

    Petryk, Michael W. P.

    2006-10-01

    The CH stretching overtone transitions of the nerve agent sarin (O-isopropyl methylphosphonofluoridate) are of interest to the standoff detection of chemical warfare agents, as many of these transitions occur near regions where small, efficient, portable diode lasers (originally developed for use in the telecommunications industry) operate. However, the interpretation of experimental vibrational overtone spectra is often difficult, and the computational simulation of overtone transitions in a molecule is challenging. Presented herein are the simulated CH overtone stretching transitions in sarin. Spectral regions are simulated from overtone transition energies and intensities, both of which are calculated within the harmonically coupled anharmonic oscillator (HCAO) model. Data for HCAO calculations are obtained from ab initio calculations, without any recourse to experimental data.

  13. Stretched cell cycle model for proliferating lymphocytes

    PubMed Central

    Dowling, Mark R.; Kan, Andrey; Heinzel, Susanne; Zhou, Jie H. S.; Marchingo, Julia M.; Wellard, Cameron J.; Markham, John F.; Hodgkin, Philip D.

    2014-01-01

    Stochastic variation in cell cycle time is a consistent feature of otherwise similar cells within a growing population. Classic studies concluded that the bulk of the variation occurs in the G1 phase, and many mathematical models assume a constant time for traversing the S/G2/M phases. By direct observation of transgenic fluorescent fusion proteins that report the onset of S phase, we establish that dividing B and T lymphocytes spend a near-fixed proportion of total division time in S/G2/M phases, and this proportion is correlated between sibling cells. This result is inconsistent with models that assume independent times for consecutive phases. Instead, we propose a stretching model for dividing lymphocytes where all parts of the cell cycle are proportional to total division time. Data fitting based on a stretched cell cycle model can significantly improve estimates of cell cycle parameters drawn from DNA labeling data used to monitor immune cell dynamics. PMID:24733943

  14. Stretching cells and delivering drugs with bubbles

    NASA Astrophysics Data System (ADS)

    Ohl, Claus-Dieter; Li, Fenfang; Chon U, Chan; Gao, Yu; Xu, Chenjie

    2015-11-01

    In this talk we'll review our work on impulsive cell stretching using cavitation bubbles and magnetic microbubbles for drug delivery. For sufficient short times cells can sustain a much larger areal strain than the yield strain obtained from quasi-static stretching. Experiments with red blood cells show that even then the rupture of the cell is slow process; it is caused by diffusive swelling rather than mechanical violation of the plasma membrane. In the second part we'll discuss bubbles coated with magnetic and drug loaded particles. These bubbles offer an interesting vector for on demand delivery of drugs using mild ultrasound and magnetic fields. We report on basic experiments in microfluidic channels revealing the release of the agent during bubble oscillations and first in vivo validation with a mouse tumor model. Singapore National Research Foundations Competitive Research Program funding (NRF-CRP9-2011-04).

  15. The role of stretching in tendon injuries.

    PubMed

    Witvrouw, E; Mahieu, N; Roosen, P; McNair, P

    2007-04-01

    The function of tendons can be classified into two categories: tensile force transmission, and storage and release of elastic energy during locomotion. The action of tendons in storing and releasing energy is mainly seen in sports activities with stretch-shortening cycles (SSCs). The more intense the SSC movements are (jumping-like activities), the more frequently tendon problems are observed. High SSC movements impose high loads on tendons. Consequently, tendons that frequently deal with high SSC motion require a high energy-absorbing capacity to store and release this large amount of elastic energy. As the elasticity of tendon structures is a leading factor in the amount of stored energy, prevention and rehabilitation programmes for tendon injuries should focus on increasing this tendon elasticity in athletes performing high SSC movements. Recently, it has been shown that ballistic stretching can significantly increase tendon elasticity. These findings have important clinical implications for treatment and prevention of tendon injuries.

  16. Modeling aftershocks as a stretched exponential relaxation

    NASA Astrophysics Data System (ADS)

    Mignan, A.

    2015-11-01

    The decay rate of aftershocks has been modeled as a power law since the pioneering work of Omori in the late nineteenth century. Although other expressions have been proposed in recent decades to describe the temporal behavior of aftershocks, the number of model comparisons remains limited. After reviewing the aftershock models published from the late nineteenth century until today, I solely compare the power law, pure exponential and stretched exponential expressions defined in their simplest forms. By applying statistical methods recommended recently in applied mathematics, I show that all aftershock sequences tested in three regional earthquake catalogs (Southern and Northern California, Taiwan) and with three declustering techniques (nearest-neighbor, second-order moment, window methods) follow a stretched exponential instead of a power law. These results infer that aftershocks are due to a simple relaxation process, in accordance with most other relaxation processes observed in Nature.

  17. Field observations of the electrostatic charges of blowing snow in Hokkaido, Japan

    NASA Astrophysics Data System (ADS)

    Omiya, S.; Sato, A.

    2011-12-01

    An electrostatic charge of blowing snow may be a contributing factor in the formation of a snow drift and a snow cornice, and changing of the trajectory of own motion. However, detailed electrification characteristics of blowing snow are not known as there are few reports of charge measurements. We carried out field observations of the electrostatic charges of blowing snow in Tobetsu, Hokkaido, Japan in the mid winter of 2011. An anemovane and a thermohygrometer were used for the meteorological observation. Charge-to-mass ratios of blowing snow were obtained by a Faraday-cage, an electrometer and an electric balance. In this observation period, the air temperature during the blowing snow event was -6.5 to -0.5 degree Celsius. The measured charges in this observation were consistent with the previous studies in sign, which is negative, but they were smaller than the previous one. In most cases, the measured values increased with the temperature decrease, which corresponds with previous studies. However, some results contradicted the tendency, and the maximum value was obtained on the day of the highest air temperature of -0.5 degree Celsius. This discrepancy may be explained from the difference of the snow surface condition on observation day. The day when the maximum value was obtained, the snow surface was covered with old snow, and hard. On the other hand, in many other cases, the snow surface was covered with the fresh snow, and soft. Blowing snow particles on the hard surface can travel longer distance than on the soft one. Therefore, it can be surmised that the hard surface makes the blowing snow particles accumulate a lot of negative charges due to a large number of collisions to the surface. This can be supported by the results of the wind tunnel experiments by Omiya and Sato (2011). By this field observation, it was newly suggested that the electrostatic charge of blowing snow are influenced greatly by the difference of the snow surface condition. REFERENCE

  18. NASA/MSFC Large Stretch Press Study

    NASA Technical Reports Server (NTRS)

    Choate, M. W.; Nealson, W. P.; Jay, G. C.; Buss, W. D.

    1985-01-01

    The purpose of this study was to: A. assess and document the advantages/disadvantages of a government agency investment in a large stretch form press on the order of 5000 tons capacity (per jaw); B. develop a procurement specification for the press; and C. provide trade study data that will permit an optimum site location. Tasks were separated into four major elements: cost study, user survey, site selection, and press design/procurement specification.

  19. Computational film cooling effectiveness of dual trench configuration on flat plate at moderate blowing ratios

    NASA Astrophysics Data System (ADS)

    Abdala, Antar M. M.; Zheng, Qun; Elwekeel, Fifi N. M.; Dong, Ping

    2013-06-01

    In the present work, computational simulations was made using ANSYS CFX to predict the improvements in film cooling performance with dual trench. Dual-trench configuration consists of two trenches together, one wider trench and the other is narrow trench that extruded from the wider one. Several blowing ratios in the range (0.5:5) were investigated. The pitch-to-diameter ratio of 2.775 is used. By using the dual trench configuration, the coolant jet impacted the trench wall two times allowing increasing the spreading of coolant laterally in the trench, reducing jet velocity and jet completely covered on the surface. The results indicate that this configuration increased adiabatic effectiveness as blowing ratio increased. The spatially averaged adiabatic effectiveness reached 57.6% for at M= 2. No observed film blow-off at all blowing ratios. The adiabatic film effectiveness of dual trench case outperformed the narrow trench case, laidback fan-shaped hole, fan-shaped hole and cylinder hole at different blowing ratios.

  20. Lateral control at high angles of attack using pneumatic blowing through a chined forebody

    NASA Technical Reports Server (NTRS)

    Arena, A. S., Jr.; Nelson, R. C.; Schiff, L. B.

    1993-01-01

    Directional control through the use of pneumatic blowing was investigated on a generic subscale model with a chined forebody with blowing through a chine slot in a direction normal to the forebody surface. Comparisons are made with a vertical tail on and off, and with control through rudder deflection. Force and moment data were obtained for various blowing coefficients over a 0-75 deg alpha range, and flow visualization was also conducted in order to see qualitative effects on the flowfield. Blowing through a chined forebody generates yaw moments at large alpha where control surfaces lose their effectiveness; these moments are much larger than obtained by jet thrust alone, since the forebody flowfield is modified through the interaction of the jet with the chine vortices. Directional control increased with angle of attack for a given blowing coefficient until a maximum was reached. Further increases in angle of attack results in a rapid loss of effectiveness. For angles of attack above 60 deg, yaw moments are generated by simple jet thrust effect. The effectiveness of the pneumatic system depended on tail configuration.

  1. Severe storms and blow-down disturbances in the Amazon forest

    NASA Astrophysics Data System (ADS)

    Espirito-Santo, F. D.; Keller, M.; Braswell, B.; Nelson, B. W.; Vicente, G.; Frolking, S.

    2007-12-01

    Large natural disturbances (> 1 ha) in old-growth tropical forests are caused by a variety of processes such as landslides, fires, wind, and cyclonic storms. We analyzed the pattern of large forest disturbances apparently caused by severe winds (blow-downs) in a mostly unmanaged portion of the Brazilian Amazon using a longitudinal transect of Landsat images (27 scenes between 6°43'W 68°50'S and 2°16'W 51°51'S) and daily precipitation estimates based on NOAA satellite data. We found 170 blow-downs with an average area of 3 km2. Most blow-down disturbances occurred in the Western Amazon between 67°W and 58°W. A map of heavy rainfall (> 20 mm d-1) showed that the maximum frequency of heavy daily rainfall (~80 days y-1) occurred around 63°W in our study region. We found a close relationship between the frequency of heavy storms and the occurrence of blow-down disturbances events. This, in turns, suggests a close connection between severe weather and the rate of forest turnover caused by blow-down disturbances. The forest turnover time calculated for these disturbances within 9 Eastern Landsat scenes studied was almost 9000 years whereas for the 18 scenes in the Western Amazon, turnover time was closer to 1200 year. Large disturbances may have a significant influence on the spatial pattern of forest dynamics and productivity of the Amazon.

  2. On the effect of leading edge blowing on circulation control airfoil aerodynamics

    NASA Technical Reports Server (NTRS)

    Mclachlan, B. G.

    1987-01-01

    In the present context the term circulation control is used to denote a method of lift generation that utilizes tangential jet blowing over the upper surface of a rounded trailing edge airfoil to determine the location of the boundary layer separation points, thus setting an effective Kutta condition. At present little information exists on the flow structure generated by circulation control airfoils under leading edge blowing. Consequently, no theoretical methods exist to predict airfoil performance under such conditions. An experimental study of the flow field generated by a two dimensional circulation control airfoil under steady leading and trailing edge blowing was undertaken. The objective was to fundamentally understand the overall flow structure generated and its relation to airfoil performance. Flow visualization was performed to define the overall flow field structure. Measurements of the airfoil forces were also made to provide a correlation of the observed flow field structure to airfoil performance. Preliminary results are presented, specifically on the effect on the flow field structure of leading edge blowing, alone and in conjunction with trailing edge blowing.

  3. Computational analysis of forebody tangential slot blowing on the high alpha research vehicle

    NASA Technical Reports Server (NTRS)

    Gee, Ken

    1994-01-01

    Current and future fighter aircraft can maneuver in the high-angle-of-attack flight regime while flying at low subsonic and transonic freestream Mach numbers. However, at any flight speed, the ability of the vertical tails to generate yawing moment is limited in high-angle-of-attack flight. Thus, any system designed to provide the pilot with additional side force and yawing moment must work in both low subsonic and transonic flight. However, previous investigations of the effectiveness of forebody tangential slot blowing in generating the desired control forces and moments have been limited to the low subsonic freestream flow regime. In order to investigate the effectiveness of tangential slot blowing in transonic flight, a computational fluid dynamics analysis was carried out during the grant period. Computational solutions were obtained at three different freestream Mach numbers and at various jet mass flow ratios. All results were obtained using the isolated F/A-18 forebody grid geometry at 30.3 degrees angle of attack. One goal of the research was to determine the effect of freestream Mach number on the effectiveness of forebody tangential slot blowing in generating yawing moment. The second part of the research studied the force onset time lag associated with blowing. The time required for the yawing moment to reach a steady-state value from the onset of blowing may have an impact on the implementation of a pneumatic system on a flight vehicle.

  4. Dynamics and structure of stretched flames

    SciTech Connect

    Law, C.K.

    1993-12-01

    This program aims to gain fundamental understanding on the structure, geometry, and dynamics of laminar premixed flames, and relate these understanding to the practical issues of flame extinction and stabilization. The underlying fundamental interest here is the recent recognition that the response of premixed flames can be profoundly affected by flame stretch, as manifested by flow nonuniformity, flame curvature, and flame/flow unsteadiness. As such, many of the existing understanding on the behavior of premixed flames need to be qualitatively revised. The research program consists of three major thrusts: (1) detailed experimental and computational mapping of the structure of aerodynamically-strained planar flames, with emphasis on the effects of heat loss, nonequidiffusion, and finite residence time on the flame thickness, extent of incomplete reaction, and the state of extinction. (2) Analytical study of the geometry and dynamics of stretch-affected wrinkled flame sheets in simple configurations, as exemplified by the Bunsen flame and the spatially-periodic flame, with emphasis on the effects of nonlinear stretch, the phenomena of flame cusping, smoothing, and tip opening, and their implications on the structure and burning rate of turbulent flames. (3) Stabilization and blowoff of two-dimensional inverted premixed and stabilization and determining the criteria governing flame blowoff. The research is synergistically conducted through the use of laser-based diagnostics, computational simulation of the flame structure with detailed chemistry and transport, and mathematical analysis of the flame dynamics.

  5. Dynamo theory, vorticity generation, and exponential stretching.

    PubMed

    Friedlander, Susan; Vishik, Misha M.

    1991-08-01

    A discussion is given of the analogy between the dynamo equation for the generation of a magnetic field by the motion of an electrically conducting fluid and the equation for the evolution of vorticity of a viscous fluid. In both cases exponential stretching is an important feature of the underlying instability problem. For the "fast" dynamo problem, the existence of exponential stretching (i.e., the positivity of the Lyapunov exponent) somewhere in the flow is a necessary condition when the flow is smooth. An example is presented of a flow with exponential stretching (an Anosov flow) that supports fast dynamo action. A parallel treatment is described for the linearized Navier-Stokes equations for the motion of a viscous fluid. In this problem the analogous necessary condition for "fast vorticity generation" is the existence of some instability in the corresponding Euler (i.e., inviscid) equation. Dynamo theory methods give a second related result, namely a universal geometric estimate from below on the growth rate of a small perturbation in an inviscid fluid. This bound gives an effective sufficient condition for local instability for Eulers equations. In particular, it is proved that a steady flow with a hyperbolic stagnation point is unstable. The growth rate of an infinitesimal perturbation in a metric with derivatives depends on this metric. This dependence is completely described.

  6. Stretch Moduli of Ribonucleotide Embedded Short DNAs

    NASA Astrophysics Data System (ADS)

    Chiu, Hsiang-Chih; Koh, Kyung Duk; Riedo, Elisa; Storici, Francesca

    2013-03-01

    Understanding the mechanical properties of DNA is essential to comprehending the dynamics of many cellular functions. DNA deformations are involved in many mechanisms when genetic information needs to be stored and used. In addition, recent studies have found that Ribonucleotides (rNMPs) are among the most common non-standard nucleotides present in DNA. The presences of rNMPs in DNA might cause mutation, fragility or genotoxicity of chromosome but how they influence the structure and mechanical properties of DNA remains unclear. By means of Atomic Force Microscopy (AFM) based single molecule spectroscopy, we measure the stretch moduli of double stranded DNAs (dsDNA) with 30 base pairs and 5 equally embedded rNMPs. The dsDNAs are anchored on gold substrate via thiol chemistry, while the AFM tip is used to pick up and stretch the dsDNA from its free end through biotin-streptavidin bonding. Our preliminary results indicate that the inclusion of rNMPs in dsDNA might significantly change its stretch modulus, which might be important in some biological processes.

  7. Sequencing of long stretches of repetitive DNA

    PubMed Central

    De Bustos, Alfredo; Cuadrado, Angeles; Jouve, Nicolás

    2016-01-01

    Repetitive DNA is widespread in eukaryotic genomes, in some cases making up more than 80% of the total. SSRs are a type of repetitive DNA formed by short motifs repeated in tandem arrays. In some species, SSRs may be organized into long stretches, usually associated with the constitutive heterochromatin. Variation in repeats can alter the expression of genes, and changes in the number of repeats have been linked to certain human diseases. Unfortunately, the molecular characterization of these repeats has been hampered by technical limitations related to cloning and sequencing. Indeed, most sequenced genomes contain gaps owing to repetitive DNA-related assembly difficulties. This paper reports an alternative method for sequencing of long stretches of repetitive DNA based on the combined use of 1) a linear vector to stabilize the cloning process, and 2) the use of exonuclease III for obtaining progressive deletions of SSR-rich fragments. This strategy allowed the sequencing of a fragment containing a stretch of 6.2 kb of continuous SSRs. To demonstrate that this procedure can sequence other kinds of repetitive DNA, it was used to examine a 4.5 kb fragment containing a cluster of 15 repeats of the 5S rRNA gene of barley. PMID:27819354

  8. Short Durations of Static Stretching when Combined with Dynamic Stretching do not Impair Repeated Sprints and Agility

    PubMed Central

    Wong, Del P.; Chaouachi, Anis; Lau, Patrick W.C.; Behm, David G.

    2011-01-01

    This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA) and change of direction (COD). Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s). Three dynamic stretching exercises of 30 s duration were then performed (90 s total). Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. Key points The duration of combined static and dynamic stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit and reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). No significant differences in RSA and COD between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. The short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. PMID:24149890

  9. Experimental Characterization of Stretch-Bending Formability of AHSS Sheets

    NASA Astrophysics Data System (ADS)

    Kitting, Daniela; Ofenheimer, Aldo; Pauli, Heinrich; Till, Edwin T.

    2011-05-01

    Deformation conditions of combined stretching and bending are known to enhance material formability compared to forming conditions without bending (e.g. in-plane stretching). These phenomena can be observed for most conventional steel grades but is even more pronounced for Advanced High Strength Steel (AHSS) sheets. Consequently, there is an urgent need in industry to quantify the phenomena of enhanced material formability due to bending effects. In this work new stretch-bend test setups are presented which can be used in addition to the conventional Angular Stretch Bend Test to systematically investigate the influence of various stretch-bending deformation conditions on the formability of AHSS sheets.

  10. Blow-down tests in a sodium-heated steam generator tube. [LMFBR

    SciTech Connect

    France, D.M.; Carlson, R.D.; Chiang, T.

    1983-01-01

    The design of steam generators for liquid metal fast breeder reactor (LMFBR) electric power plants is based on both normal load operation and plant transient conditions. Perhaps the most severe transient to which an LMFBR steam generator may be subjected is known as the water-side isolation and dump transient, often called the blow-down transient. LMFBR steam generators must be designed to accommodate a small but finite number of the blow-down transients. The purpose of this investigation was to perform a blow-down experiment in a well instrumented, full scale, single tube model of an LMFBR steam generator. The data may be used directly in steam generator design and as a validation point for steam generator mathematical models in plant transient computer codes.

  11. Impact of pulsed blowing jet on aerodynamic characteristics of wind turbine airfoils

    NASA Astrophysics Data System (ADS)

    Bobonea, Andreea

    2012-11-01

    Wind turbine growth in size and weight made it impossible to control turbines passively as they were controlled in the past. Current efforts focus on increasing their aerodynamic efficiency and operational range through active flow control methods. One of the main methods of active flow control is the usage of blowing devices with constant or pulsed jets. By adding stored high-momentum air through slots into the boundary layer, they overcome adverse pressure gradients and postpone separation. Pulsed blowing sends short pulses rather than a continuous jet of fluid into the boundary layer and has been found to be more effective. Through CFD simulations over a 2D wind turbine airfoil, this research highlights the impact of different slot geometries with constant/pulsed blowing, on the effectiveness of this active flow control technique.

  12. Computational study of the aerodynamics and control by blowing of asymmetric vortical flows over delta wings

    NASA Technical Reports Server (NTRS)

    Craig, Ken

    1991-01-01

    Some of the work is described which was done in a study of the flow field produced by tangential leading edge blowing on a 60 deg. delta wing. The flow is studied computationally by solving the Thin Layer Navier-Stokes equations. Steady state flow fields are calculated for various angles of attack and yaw, with and without the presence of tangential leading edge blowing. The effectiveness of blowing as a rolling moment control mechanism to extend the envelope of controllability is illustrated at pre- and post-stall angles of attack. The numerical grid is generated using algebraic grid generation and various interpolation and blending techniques. The jet emanates from a slot with linearly varying thickness and is introduced into the flow field using the concept of an actuator plane, thereby not requiring resolution of the jet slot geometry. The Baldwin-Lomax algebraic turbulence model is used to provide turbulent closure. The computational results are compared with those of experiments.

  13. Molecular identification of blow flies recovered from human cadavers during crime scene investigations in Malaysia.

    PubMed

    Kavitha, Rajagopal; Nazni, Wasi Ahmad; Tan, Tian Chye; Lee, Han Lim; Isa, Mohd Noor Mat; Azirun, Mohd Sofian

    2012-12-01

    Forensic entomology applies knowledge about insects associated with decedent in crime scene investigation. It is possible to calculate a minimum postmortem interval (PMI) by determining the age and species of the oldest blow fly larvae feeding on decedent. This study was conducted in Malaysia to identify maggot specimens collected during crime scene investigations. The usefulness of the molecular and morphological approach in species identifications was evaluated in 10 morphologically identified blow fly larvae sampled from 10 different crime scenes in Malaysia. The molecular identification method involved the sequencing of a total length of 2.2 kilo base pairs encompassing the 'barcode' fragments of the mitochondrial cytochrome oxidase I (COI), cytochrome oxidase II (COII) and t-RNA leucine genes. Phylogenetic analyses confirmed the presence of Chrysomya megacephala, Chrysomya rufifacies and Chrysomya nigripes. In addition, one unidentified blow fly species was found based on phylogenetic tree analysis.

  14. Control of turbulent boundary layer through air blowing due to external-flow resources

    NASA Astrophysics Data System (ADS)

    Kornilov, V. I.; Boiko, A. V.; Kavun, I. N.

    2015-07-01

    The possibility to control turbulent incompressible boundary layer using air blowing through a finely perforated wall presenting part of the streamlined flat-plate surface was examined. The control was exercised via an action on the state and characteristics of the near-wall flow exerted by controlled (through variation of external-pressure-flow velocity) blowing of air through an air intake installed on the idle side of the plate. A stable reduction of the local values of skin friction coefficient along the model, reaching 50 % at the end of the perforated area, has been demonstrated. The obtained experimental and calculated data are indicative of a possibility to model the process of turbulentboundary-layer control by air blowing due to external-flow resources.

  15. Microbial effects on the development of forensically important blow fly species.

    PubMed

    Crooks, Esther R; Bulling, Mark T; Barnes, Kate M

    2016-09-01

    Colonisation times and development rates of specific blow fly species are used to estimate the minimum Post Mortem Interval (mPMI). The presence or absence of bacteria on a corpse can potentially affect the development and survival of blow fly larvae. Therefore an understanding of microbial-insect interactions is important for improving the interpretation of mPMI estimations. In this study, the effect of two bacteria (Escherichia coli and Staphylococcus aureus) on the growth rate and survival of three forensically important blow fly species (Lucilia sericata, Calliphora vicina and Calliphora vomitoria) was investigated. Sterile larvae were raised in a controlled environment (16:8h day: night light cycle, 23:21°C day: night temperature cycle and a constant 35% relative humidity) on four artificial diets prepared with 100μl of 10(5) CFU bacterial solutions as follows: (1) E. coli, (2) S. aureus, (3) a 50:50 E. coli:S. aureus mix and (4) a sterile bacteria-free control diet. Daily measurements (length, width and weight) were taken from first instar larvae through to the emergence of adult flies. Survival rates were also determined at pupation and adult emergence. Results indicate that bacteria were not essential for the development of any of the blow fly species. However, larval growth rates were affected by bacterial diet, with effects differing between blow fly species. Peak larval weights also varied according to species-diet combination; C. vomitoria had the largest weight on E. coli and mixed diets, C. vicina had the largest weight on S. aureus diets, and treatment had no significant effect on the peak larval weight of L. sericata. These results indicate the potential for the bacteria that larvae are exposed to during development on a corpse to alter both developmental rates and larval weight in some blow fly species.

  16. Does residual force enhancement increase with increasing stretch magnitudes?

    PubMed

    Hisey, Brandon; Leonard, Tim R; Herzog, Walter

    2009-07-22

    It is generally accepted that force enhancement in skeletal muscles increases with increasing stretch magnitudes. However, this property has not been tested across supra-physiological stretch magnitudes and different muscle lengths, thus it is not known whether this is a generic property of skeletal muscle, or merely a property that holds for small stretch magnitudes within the physiological range. Six cat soleus muscles were actively stretched with magnitudes varying from 3 to 24 mm at three different parts of the force-length relationship to test the hypothesis that force enhancement increases with increasing stretch magnitude, independent of muscle length. Residual force enhancement increased consistently with stretch amplitudes on the descending limb of the force-length relationship up to a threshold value, after which it reached a plateau. Force enhancement did not increase with stretch amplitude on the ascending limb of the force-length relationship. Passive force enhancement was observed for all test conditions, and paralleled the behavior of the residual force enhancement. Force enhancement increased with stretch magnitude when stretching occurred at lengths where there was natural passive force within the muscle. These results suggest that force enhancement does not increase unconditionally with increasing stretch magnitude, as is generally accepted, and that increasing force enhancement with stretch appears to be tightly linked to that part of the force-length relationship where there is naturally occurring passive force.

  17. Effects of cervical self-stretching on slow vital capacity.

    PubMed

    Han, Dongwook; Yoon, Nayoon; Jeong, Yeongran; Ha, Misook; Nam, Kunwoo

    2015-07-01

    [Purpose] This study investigated the effects of self-stretching of cervical muscles, because the accessory inspiratory muscle is considered to improve pulmonary function. [Subjects] The subjects were 30 healthy university students 19-21 years old who did not have any lung disease, respiratory dysfunction, cervical injury, or any problems upon cervical stretching. [Methods] Spirometry was used as a pulmonary function test to measure the slow vital capacity before and after stretching. The slow vital capacity of the experimental group was measured before and after cervical self-stretching. Meanwhile, the slow vital capacity of the control group, which did not perform stretching, was also measured before and after the intervention. [Results] The expiratory vital capacity, inspiratory reserve volume, and expiratory reserve volume of the experimental group increased significantly after the cervical self-stretching. [Conclusion] Self-stretching of the cervical muscle (i.e., the inspiratory accessory muscle) improves slow vital capacity.

  18. Secondary structure of double-stranded DNA under stretching: Elucidation of the stretched form

    SciTech Connect

    Maaloum, M.; Muller, P.; Beker, A-F.

    2011-03-15

    Almost two decades ago, measurements of force versus extension on isolated double-stranded DNA molecules revealed a force plateau. This unusual stretching phenomenon in DNA suggests that the long molecules may be extended from the usual B form into a new conformation. Different models have been proposed to describe the nature of DNA in its stretched form, S-DNA. Using atomic force microscopy combined with a molecular combing method, we identified the structure of {lambda}-phage DNA for different stretching values. We provide strong evidence for the existence of a first-order transition between B form and S form. Beyond a certain extension of the natural length, DNA molecules adopt a new double-helix conformation characterized by a diameter of 1.2 nm and a helical pitch of18 nm.

  19. Blow up of solutions to the nonlinear Schroedinger equations on manifolds

    SciTech Connect

    Ma Li; Zhao Lin

    2007-05-15

    In this paper, we partially settle down the long-standing open problem of the finite time blow-up property about the nonlinear Schroedinger equations on some Riemannian manifolds such as the standard 2-sphere S{sup 2} and the hyperbolic 2-space H{sup 2}(-1). Using the similar idea, we establish such blow-up results on higher dimensional standard sphere and hyperbolic n-space. Extensions to n-dimensional Riemannian warped product manifolds with n{>=}2 are also given.

  20. Linearized transfer between coplanar circular orbits using blow down propulsion system

    NASA Technical Reports Server (NTRS)

    Kechichian, J. A.; White, L. K.

    1982-01-01

    A closed form solution is presented for the coplanar transfer between nearby circular orbits for spacecraft using their own blow down propulsion system. The decaying thrust is applied along the local horizontal and the linearized equation of motion in the orbital elements formulation are used to describe the transfer which consists of a thrust-coast-relight program. Sensitivity partials are also presented analytically in order to study the effect of maneuver execution errors and various other parameters affecting the blow down propulsion system characteristics on the transfer. This strategy is applied to study the transfer of the TOPEX spacecraft from the Shuttle parking orbit to its final operational orbit.

  1. On the sublimation of blowing snow and of snow in canopies

    NASA Astrophysics Data System (ADS)

    Taylor, P. A.; Simon, K.; Gordon, M.; Weng, W.

    2003-04-01

    Tests have been made within the Canadian Land Surface Scheme (CLASS) of various parameterizations of sublimation of blowing snow, and tested in the context of data from weather stations (Goose Bay and Resolute) in northern Canada. We will focus on parameterization schemes based on results obtained with the PIEKTUK model of blowing snow. In addition we will present preliminary results concerning the parameterization of sublimation of snow caught in tree canopies, using schemes similar to those for evaporation from wet canopies. This is considered to be a major factor in the water budgets of forested areas in northern Canada.

  2. Investigations of transonic buffet control on civil aircraft wing with the use of tangential jet blowing

    NASA Astrophysics Data System (ADS)

    Abramova, K. A.; Petrov, A. V.; Potapchick, A. V.; Soudakov, V. G.

    2016-10-01

    Numerical and experimental investigations of transonic buffet control by tangential jet blowing are presented. To suppress the shock-induced boundary layer separation and the buffet at transonic speeds, compressed air jet is blown through a small slot nozzle tangentially to the upper surface of the supercritical airfoil. Numerical simulations were carried out on the basis of the unsteady Reynolds averaged Navier-Stokes (URANS) equations. Experimental studies of the tangential jet blowing were performed in the transonic wind tunnel T-112 of TsAGI. Results show that the jet moves the shock downstream, increases lift, suppresses flow separation under shock foot and delays buffet onset.

  3. Blow-up conditions for two dimensional modified Euler-Poisson equations

    NASA Astrophysics Data System (ADS)

    Lee, Yongki

    2016-09-01

    The multi-dimensional Euler-Poisson system describes the dynamic behavior of many important physical flows, yet as a hyperbolic system its solution can blow-up for some initial configurations. This article strives to advance our understanding on the critical threshold phenomena through the study of a two-dimensional modified Euler-Poisson system with a modified Riesz transform where the singularity at the origin is removed. We identify upper-thresholds for finite time blow-up of solutions for the modified Euler-Poisson equations with attractive/repulsive forcing.

  4. Blow-up phenomena and persistence property for the modified b-family of equations

    NASA Astrophysics Data System (ADS)

    Wang, Ying; Zhu, Min

    2017-02-01

    In this paper, we study the blow-up mechanism and persistence property of solutions to the modified b-family of equations. The dynamics of the blow-up quantity along the characteristics is established by the Riccati-type differential inequality with various parameters. The key feature of the method is to refine the analysis on the growth rate of the relative ratio between solution and its gradient by performing a vertical shift. Furthermore, the persistence results for the solution are established in weighted spaces.

  5. Self-Inflicted Hammer Blows to the Cranial Vault: An Interdisciplinary Challenge

    PubMed Central

    Kim, Seong Woong; Putzke, Michael; Uhl, Eberhard; Krishnan, Kartik G.

    2016-01-01

    Depression is predicted to be the most common cause of disability in the coming decade. Self-inflicted hammer blow to the cranium is a rare phenomenon seen in patients with a history of attempted suicide. The resulting comminuted depressed skull fracture of the midline vertex is life threatening. Rapid interdisciplinary communication and intervention are essential to reduce morbidity and mortality. We present a case of self-inflicted hammer blows to the head, review the relevant literature on this topic, and discuss neurosurgical and psychiatric implications. PMID:27722022

  6. Asymptotic analysis of reaction-diffusion-advection problems: Fronts with periodic motion and blow-up

    NASA Astrophysics Data System (ADS)

    Nefedov, Nikolay

    2017-02-01

    This is an extended variant of the paper presented at MURPHYS-HSFS 2016 conference in Barcelona. We discuss further development of the asymptotic method of differential inequalities to investigate existence and stability of sharp internal layers (fronts) for nonlinear singularly perturbed periodic parabolic problems and initial boundary value problems with blow-up of fronts for reaction-diffusion-advection equations. In particular, we consider periodic solutions with internal layer in the case of balanced reaction. For the initial boundary value problems we prove the existence of fronts and give their asymptotic approximation including the new case of blowing-up fronts. This case we illustrate by the generalised Burgers equation.

  7. Noise Benefits of Rotor Trailing Edge Blowing for a Model Turbofan

    NASA Technical Reports Server (NTRS)

    Woodward, Richard P.; Fite, E. Brian; Podboy, Gary G.

    2007-01-01

    An advanced model turbofan was tested in the NASA Glenn 9- by 15-Foot Low Speed Wind Tunnel (9x15 LSWT) to explore far field acoustic effects associated with rotor Trailing-Edge-Blowing (TEB) for a modern, 1.294 stage pressure ratio turbofan model. The TEB rotor (Fan9) was designed to be aerodynamically similar to the previously tested Fan1, and used the same stator and nacelle hardware. Fan9 was designed with trailing edge blowing slots using an external air supply directed through the rotor hub. The TEB flow was heated to approximate the average fan exit temperature at each fan test speed. Rotor root blockage inserts were used to block TEB to all but the outer 40 and 20% span in addition to full-span blowing. A configuration with full-span TEB on alternate rotor blades was also tested. Far field acoustic data were taken at takeoff/approach conditions at 0.10 tunnel Mach. Far-field acoustic results showed that full-span blowing near 2.0% of the total flow could reduce the overall sound power level by about 2 dB. This noise reduction was observed in both the rotor-stator interaction tones and for the spectral broadband noise levels. Blowing only the outer span region was not very effective for lowering noise, and actually increased the far field noise level in some instances. Full-span blowing of alternate blades at 1.0% of the overall flow rate (equivalent to full-span blowing of all blades at 2.0% flow) showed a more modest noise decrease relative to full-span blowing of all blades. Detailed hot film measurements of the TEB rotor wake at 2.0% flow showed that TEB was not every effective for filling in the wake defect at approach fan speed toward the tip region, but did result in overfilling the wake toward the hub. Downstream turbulence measurements supported this finding, and support the observed reduction in spectral broadband noise.

  8. On global existence, energy decay and blow-up criteria for the Hall-MHD system

    NASA Astrophysics Data System (ADS)

    Wan, Renhui; Zhou, Yong

    2015-12-01

    In this paper, we obtain global existence and energy decay for 3D Hall-magnetohydrodynamics (Hall-MHD) system with - Δu and - ΔB. Besides the classical energy method and Besov space techniques, the interpolating inequalities are crucial in the proof of decay estimates. Then two Osgood type blow-up criteria are established. Our results improve the corresponding theorems in [3] and [4]. In addition, we establish two Beale-Kato-Majda blow-up criterion for the generalized version of Hall-MHD with - Δu and (- Δ) β B, β > 1.

  9. Acute effects of dynamic stretching, static stretching, and light aerobic activity on muscular performance in women.

    PubMed

    Curry, Brad S; Chengkalath, Devendra; Crouch, Gordon J; Romance, Michelle; Manns, Patricia J

    2009-09-01

    The purpose of this study was to compare three warm-up protocols--static stretching, dynamic stretching, and light aerobic activity--on selected measures of range of motion and power in untrained females and to investigate the sustained effects at 5 and 30 minutes after warm-up. A total of 24 healthy females (ages 23-29 years) attended one familiarization session and three test sessions on nonconsecutive days within 2 weeks. A within-subject design protocol with the testing investigators blinded to the subjects' warm-up was followed. Each session started with 5 minutes of light aerobic cycling followed by pretest baseline measures. Another 5 minutes of light aerobic cycling was completed and followed by one of the three randomly selected warm-up interventions (static stretching, dynamic stretching, or light aerobic activity). The following posttest outcome measures were collected 5 and 30 minutes following the intervention: modified Thomas test, countermovement jump, and isometric time to peak force knee extension measured by dynamometer. Analysis of the data revealed significant time effects on range of motion and countermovement jump changes. No significant differences (p > 0.05) were found between the warm-up conditions on any of the variables. The variation in responses to warm-up conditions emphasizes the unique nature of individual reactions to different warm-ups; however, there was a tendency for warm-ups with an active component to have beneficial effects. The data suggests dynamic stretching has greater applicability to enhance performance on power outcomes compared to static stretching.

  10. Nav channel mechanosensitivity: activation and inactivation accelerate reversibly with stretch.

    PubMed

    Morris, Catherine E; Juranka, Peter F

    2007-08-01

    Voltage-gated sodium channels (Nav) are modulated by many bilayer mechanical amphiphiles, but whether, like other voltage-gated channels (Kv, HCN, Cav), they respond to physical bilayer deformations is unknown. We expressed human heart Nav1.5 pore alpha-subunit in oocytes (where, unlike alphaNav1.4, alphaNav1.5 exhibits normal kinetics) and measured small macroscopic currents in cell-attached patches. Pipette pressure was used to reversibly stretch the membrane for comparison of I(Na)(t) before, during, and after stretch. At all voltages, and in a dose-dependent fashion, stretch accelerated the I(Na)(t) time course. The sign of membrane curvature was not relevant. Typical stretch stimuli reversibly accelerated both activation and inactivation by approximately 1.4-fold; normalization of peak I(Na)(t) followed by temporal scaling ( approximately 1.30- to 1.85-fold) resulted in full overlap of the stretch/no-stretch traces. Evidently the rate-limiting outward voltage sensor motion in the Nav1.5 activation path (as in Kv1) accelerated with stretch. Stretch-accelerated inactivation occurred even with activation saturated, so an independently stretch-modulated inactivation transition is also a possibility. Since Nav1.5 channel-stretch modulation was both reliable and reversible, and required stretch stimuli no more intense than what typically activates putative mechanotransducer channels (e.g., stretch-activated TRPC1-based currents), Nav channels join the ranks of putative mechanotransducers. It is noteworthy that at voltages near the activation threshold, moderate stretch increased the peak I(Na) amplitude approximately 1.5-fold. It will be important to determine whether stretch-modulated Nav current contributes to cardiac arrhythmias, to mechanosensory responses in interstitial cells of Cajal, to touch receptor responses, and to neuropathic (i.e., hypermechanosensitive) and/or normal pain reception.

  11. Efficacy of static stretching and proprioceptive neuromuscular facilitation stretch on hamstrings length after a single session.

    PubMed

    O'Hora, John; Cartwright, Abigail; Wade, Clive D; Hough, Alan D; Shum, Gary L K

    2011-06-01

    A number of studies have investigated the efficacy of several repetitions of proprioceptive neuromuscular facilitation stretching (PNF) and static stretching (SS). However, there is limited research comparing the effects of a single bout of these stretching maneuvers. The aim of this study was to compare the effectiveness of a single bout of a therapist-applied 30-second SS vs. a single bout of therapist-applied 6-second hamstring (agonist) contract PNF. Forty-five healthy subjects between the ages of 21 and 35 were randomly allocated to 1 of the 2 stretching groups or a control group, in which no stretching was received. The flexibility of the hamstring was determined by a range of passive knee extension, measured using a universal goniometer, with the subject in the supine position and the hip at 90° flexion, before and after intervention. A significant increase in knee extension was found for both intervention groups after a single stretch (SS group = 7.53°, p < 0.01 and PNF group = 11.80°, p < 0.01). Both interventions resulted in a significantly greater increase in knee extension when compared to the control group (p < 0.01). The PNF group demonstrated significantly greater gains in knee extension compared to the SS group (mean difference 4.27°, p < 0.01). It can be concluded that a therapist applied SS or PNF results in a significant increase in hamstring flexibility. A hamstring (agonist) contract PNF is more effective than an SS in a single stretching session. These findings are important to physiotherapists or trainers working in clinical and sporting environments. Where in the past therapists may have spent time conducting multiple repetitions of a PNF and an SS, a single bout of either technique may be considered just as effective. A key component of the study methodology was the exclusion of a warm-up period before stretching. Therefore, the findings of efficacy of a single PNF are of particular relevance in sporting environments and busy clinical

  12. Stability Analysis of High-Speed Boundary-Layer Flow with Gas Injection (Briefing Charts)

    DTIC Science & Technology

    2014-06-01

    to improve the injector performance • Shaping of injector – Conical shapes – Cylindrical shape • Suction-blowing of zero mass injection • Conclusions...16Distribution A: Approved for Public Release; Distribution Unlimited Injector of conical shape 5-deg half-angle sharp cone with the injector having the slope...pressure for conical injectors (injection rate 13.5 g/s) =1 =3 Baseline (=0) Injection region 18Distribution A: Approved for Public Release

  13. How to Blow a Bubble in a Galaxy

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-10-01

    outflow from a startburst concentrated near the nuclei. Either of these outflows could blow a bubble as it first interacts with the interstellar medium.The authors show that the first category is disfavored based on observational and energetics arguments. In addition, the western-most nucleus and the bubble both align exactly with the axis of the large-scale outflows of the galaxy. Unlikely to be due to chance, this alignment is strong support in favor of the second category.Thus, its probable that the bubble is blown by an outflow that originates from the inner ~100pc around one of the nuclei, either due to a jet or a starburst wind. Further observations should be able to differentiate between these two mechanisms.CitationKelly E. Lockhart et al 2015 ApJ 810 149. doi:10.1088/0004-637X/810/2/149

  14. Huge "Superbubble" of Gas Blowing Out of Milky Way

    NASA Astrophysics Data System (ADS)

    2006-01-01

    out of the plane has to have been unusually violent," he added. The scientists speculate that the gas may be blown outward by the strong stellar winds and supernova explosions from numerous massive young stars in a cluster. "One theoretical model shows that young stars could power an outflow that matches what we see very closely," Pidopryhora said. According to that model, the superbubble probably is 10-30 million years old. "Finding this superbubble practically in our back yard is quite exciting, because these superbubbles are very important factors in how galaxies evolve," Lockman said. Superbubbles, powered by supernova explosions and young stellar winds, control the way heavy elements, produced only in the cores of stars, are distributed throughout the galaxy, the scientists said. Those heavy elements are then incorporated into the next generation of stars -- and planets -- to form. "The formation of our own Sun and planets probably was heavily influenced, if not triggered, by a nearby supernova explosion," Lockman said. In addition, if the outflow from superbubbles is energetic enough, it could blow the gas into intergalactic space, never to return to the galaxy. "This would shut down the formation of new stars in the galaxy," Pidopryhora explained. The Green Bank Telescope, dedicated in 2000, is the largest fully-steerable radio telescope in the world, with more than two acres of collecting area in its giant dish. Located within the National Radio Quiet Zone in West Virginia, the GBT provides extraordinary sensitivity for observing faint radio-emitting objects in the distant Universe. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

  15. Near-surface snow particle dynamics from particle tracking velocimetry and turbulence measurements during alpine blowing snow storms

    NASA Astrophysics Data System (ADS)

    Aksamit, Nikolas O.; Pomeroy, John W.

    2016-12-01

    Many blowing snow conceptual and predictive models have been based on simplified two-phase flow dynamics derived from time-averaged observations of bulk flow conditions in blowing snow storms. Measurements from the first outdoor application of particle tracking velocimetry (PTV) of near-surface blowing snow yield new information on mechanisms for blowing snow initiation, entrainment, and rebound, whilst also confirming some findings from wind tunnel observations. Blowing snow particle movement is influenced by complex surface flow dynamics, including saltation development from creep that has not previously been measured for snow. Comparisons with 3-D atmospheric turbulence measurements show that blowing snow particle motion immediately above the snow surface responds strongly to high-frequency turbulent motions. Momentum exchange from wind to the dense near-surface particle-laden flow appears significant and makes an important contribution to blowing snow mass flux and saltation initiation dynamics. The more complete and accurate description of near-surface snow particle motions observable using PTV may prove useful for improving blowing snow model realism and accuracy.

  16. Research and Analysis on the Physical and Chemical Properties of Molten Bath with Bottom-Blowing in EAF Steelmaking Process

    NASA Astrophysics Data System (ADS)

    Wei, Guangsheng; Zhu, Rong; Dong, Kai; Ma, Guohong; Cheng, Ting

    2016-10-01

    Bottom-blowing technology is widely adopted in electric arc furnace (EAF) steelmaking to promote the molten bath fluid flow, accelerate the metallurgical reaction, and improve the quality of molten steel. In this study, a water model experiment and a computational fluid dynamics model were established to investigate the effects of bottom-blowing gas flow rate on the fluid flow characteristics in the EAF molten bath. The results show that the interaction among the bottom-blowing gas streams influences the molten bath flow field, and increasing the bottom-blowing gas flow rate can accelerate the fluid flow and decrease the volume of the dead zone. Based on industrial application research, the physical and chemical properties of the molten bath with bottom-blowing were analyzed. Compared with traditional melting conditions without bottom-blowing, bottom-blowing technology demonstrates obvious advantages in promoting the heat transfer and metallurgical reactions in the molten bath. With the bottom-blowing arrangement, the dephosphorization and decarburization rates are accelerated, the contents of FeO and T. Fe in endpoint slag are decreased, and the endpoint carbon-oxygen equilibrium of molten steel is improved.

  17. Convective stretching and applications to mantle mixing

    NASA Astrophysics Data System (ADS)

    Conjeepurm Subramanian, Natarajan

    In this dissertation I have developed a method to quantify the stretching and orientation of infinitesimal strain ellipsoids in three-dimensional, incompressible, and unsteady flow fields. The method is used to study the mixing properties of various mantle-like flows. Chapter 1 provides a introduction to the dissertation. In Chapter 2, I discuss the mixing properties of a three-dimensional, unsteady flow in which the time dependence and three-dimensionality of the flow can be varied independently. It is found that the time dependance of the flow is a more important control on mixing. In Chapter 3, I discuss the mixing properties in a plate-driven model of mantle convection which generates both toroidal, and poloidal components in the velocity field. It is found that as the toroidal energy in the flow is increased to match the poloidal energy, the mixing becomes more homogeneous. Computing the frequency-size distribution of the stretching experienced by the heterogeneities it is found that the marble cake structure is the most likely structure for the upper mantle. In Chapter 4, I discuss the mixing properties of iso-viscous, steady, thermal convection models at infinite Prandtl number. It is found that the strain rate in these models scales uniformly as Ra-0.55. The strain rate scaling law was used to compute the mixing time in the models. The mixing time for these models was computed as ˜ 410 My for whole mantle convection and ˜ 25 My for layered mantle convection for Ra = 1x108 and ˜ 1.4 By and ˜ 100 My for Ra = 1 x 107. As in the previous chapter, the frequency size distribution corresponding to the stretching values indicates a marble cake structure for the upper mantle. In Chapter 5, I conclude the dissertation.

  18. Tensioning device for a stretched membrane collector

    DOEpatents

    Murphy, L.M.

    1984-01-01

    Disclosed is a solar concentrating collector comprising an elestic membrane member for concentrating sunlight, a frame for holding the membrane member in plane and in tension, and a tensioning means for varying the tension of the membrane member. The tensioning means is disposed at the frame and is adapted to releasably attach the membrane member thereto. The tensioning means is also adapted to uniformly and symmetrically subject the membrane member to stretching forces such that membrane stresses produced thereby are distributed uniformly over a thickness of the membrane member and reciprocal twisting moments are substantially prevented from acting about said frame.

  19. Uni-Directional Cell Stretching Device

    NASA Technical Reports Server (NTRS)

    Feeback, Daniel L. (Inventor); Clarke, Mark S. F. (Inventor)

    2000-01-01

    The present invention relates to an apparatus and method for applying various degrees of linear, mechanical loads on mammalian tissues, and in particular, for effecting linear stretching of tissue and simulating changes in hydrostatic pressures encountered during tissue contraction in vivo. The apparatus is useful for the study of mechanical loading in human tissue, and specifically, for permitting the evaluation of the effects of mechanical loading of skeletal or cardiac tissue and of the effects of removal of mechanical loading due to inactivity or the like, and the subsequent reapplication of load to these tissues.

  20. Venus Chasmata: A Lithospheric Stretching Model

    NASA Technical Reports Server (NTRS)

    Solomon, S. C.; Head, J. W.

    1985-01-01

    An outstanding problem for Venus is the characterization of its style of global tectonics, an issue intimately related to the dominant mechanism of lithospheric heat loss. Among the most spectacular and extensive of the major tectonic features on Venus are the chasmata, deep linear valleys generally interpreted to be the products of lithospheric extension and rifting. Systems of chasmata and related features can be traced along several tectonic zones up to 20,000 km in linear extent. A lithospheric stretching model was developed to explain the topographic characteristics of Venus chasmata and to constrain the physical properties of the Venus crust and lithosphere.

  1. Finite stretching of an annular plate.

    NASA Technical Reports Server (NTRS)

    Biricikoglu, V.; Kalnins, A.

    1971-01-01

    The problem of the finite stretching of an annular plate which is bonded to a rigid inclusion at its inner edge is considered. The material is assumed to be isotropic and incompressible with a Mooney-type constitutive law. It is shown that the inclusion of the effect of the transverse normal strain leads to a rapid variation in thickness which is confined to a narrow edge zone. The explicit solutions to the boundary layer equations, which govern the behavior of the plate near the edges, are presented.

  2. Tensioning device for a stretched membrane collector

    DOEpatents

    Murphy, Lawrence M.

    1984-01-01

    Disclosed is a solar concentrating collector comprising an elastic membrane member for concentrating sunlight, a frame for holding the membrane member in plane and in tension, and a tensioning means for varying the tension of the membrane member. The tensioning means is disposed at the frame and is adapted to releasably attach the membrane member thereto. The tensioning means is also adapted to uniformly and symmetrically subject the membrane member to stretching forces such that membrane stresses produced thereby are distributed uniformly over a thickness of the membrane member and reciprocal twisting moments are substantially prevented from acting about said frame.

  3. To Stretch and Search for Better Ways

    NASA Astrophysics Data System (ADS)

    Moore, John W.

    2000-06-01

    There's a lot to do to get each issue of this Journal ready for publication, and there's a lot that can go awry during that process. We the editorial staff do our utmost to make certain that each issue is the best it can possibly be, but, of necessity, a lot of our effort is focused on solving problems, correcting errors, and avoiding pitfalls. It is not surprising that we sometimes lose sight of the bigger picture--all of the things that came out as well as or better than we hoped they would. Therefore it gives us great pleasure when a reader applauds (and thereby rewards) our efforts. One such communication inspired this editorial.

    I have appreciated the extra effort put forward by the staff to make the Journal really come alive. The high quality of the Journal serves as an incentive to chemical educators to stretch and search for better ways to inspire our students.
    I fervently hope that we do encourage you "to stretch and search for better ways", not only to inspire students but in everything you do. Stretching and searching for better ways is what life, science, chemistry, and teaching are all about, and it is a wonderfully stimulating and exciting way to approach anything and everything. Sometimes, though, one's ability to stretch is akin to that of a rubber band exposed too long to sunlight. Change becomes a threat or a burden instead of an opportunity. This often happens in one area but not others, as in the case of someone doing original research but whose lecture notes are yellow with age, or someone who experiments with new teaching approaches but neglects the latest chemical discoveries. Whatever its manifestation, failure to stretch and search for better ways is a great loss, both for the individual directly involved and for others. Fortunately there are many who continually stretch and search, often in conjunction with JCE. For example, some time ago the Chair of the Board of Publication, Jerry Bell, challenged Journal

  4. Identification of CFC and HCFC substitutes for blowing polyurethane foam insulation products. Final report, September 1993-November 1994

    SciTech Connect

    Howard, P.H.; Tunkel, J.L.; Banerjee, S.

    1995-10-01

    The report gives results of a cooperative effort to identify chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) substitutes for blowing polyurethane foam insulation products. More than 100 chemicals have been identified and ranked as polyurethane foam blowing agent candidates. The systematic investigation involved the analysis of vapor thermal conductivity predictive models and utilizing this methodology to identify and screen potential new foam blowing agents. Collection of physical/chemical properties of the new candidates enabled an overall evaluation. Based on the vapor thermal conductivity, boiling point, and other important properties, the chemical compounds were ranked to identify the most promising new blowing agent candidates. To efficiently evaluate new foam blowing agents, the compounds were placed and evaluated in 14 groups based on chemical structure.

  5. Experimental investigation of tangential blowing for control of the strong shock boundary layer interaction on inlet ramps

    NASA Technical Reports Server (NTRS)

    Schwendemann, M. F.

    1981-01-01

    A 0.165-scale isolated inlet model was tested in the NASA Lewis Research Center 8-ft by 6-ft Supersonic Wind Tunnel. Ramp boundary layer control was provided by tangential blowing from a row of holes in an aft-facing step set into the ramp surface. Testing was performed at Mach numbers from 1.36 to 1.96 using both cold and heated air in the blowing system. Stable inlet flow was achieved at all Mach numbers. Blowing hole geometry was found to be significant at 1.96M. Blowing air temperature was found to have only a small effect on system performance. High blowing levels were required at the most severe test conditions.

  6. Levator Ani Muscle Stretch Induced by Simulated Vaginal Birth

    PubMed Central

    Lien, Kuo-Cheng; Mooney, Brian; DeLancey, John O. L.; Ashton-Miller, James A.

    2005-01-01

    OBJECTIVE: To develop a three-dimensional computer model to predict levator ani muscle stretch during vaginal birth. METHODS: Serial magnetic resonance images from a healthy nulliparous 34-year-old woman, published anatomic data, and engineering graphics software were used to construct a structural model of the levator ani muscles along with related passive tissues. The model was used to quantify pelvic floor muscle stretch induced during the second stage of labor as a model fetal head progressively engaged and then stretched the iliococcygeus, pubococcygeus, and puborectalis muscles. RESULTS: The largest tissue strain reached a stretch ratio (tissue length under stretch/original tissue length) of 3.26 in medial pubococcygeus muscle, the shortest, most medial and ventral levator ani muscle. Regions of the ileococcygeus, pubococcygeus, and puborectalis muscles reached maximal stretch ratios of 2.73, 2.50, and 2.28, respectively. Tissue stretch ratios were proportional to fetal head size: For example, increasing fetal head diameter by 9% increased medial pubococcygeus stretch by the same amount. CONCLUSION: The medial pubococcygeus muscles undergo the largest stretch of any levator ani muscles during vaginal birth. They are therefore at the greatest risk for stretch-related injury. PMID:14704241

  7. Polarized actin structural dynamics in response to cyclic uniaxial stretch

    PubMed Central

    Huang, Lawrence; Helmke, Brian P.

    2014-01-01

    Endothelial cell (EC) alignment to directional flow or stretch supports anti-inflammatory functions, but mechanisms controlling polarized structural adaptation in response to physical cues remain unclear. This study aimed to determine whether factors associated with early actin edge ruffling implicated in cell polarization are prerequisite for stress fiber (SF) reorientation in response to cyclic uniaxial stretch. Time-lapse analysis of EGFP-actin in confluent ECs showed that onset of either cyclic uniaxial or equibiaxial stretch caused a non-directional increase in edge ruffling. Edge activity was concentrated in a direction perpendicular to the stretch axis after 60 min, consistent with the direction of SF alignment. Rho-kinase inhibition caused reorientation of both stretch-induced edge ruffling and SF alignment parallel to the stretch axis. Arp2/3 inhibition attenuated stretch-induced cell elongation and disrupted polarized edge dynamics and microtubule organizing center reorientation, but it had no effect on the extent of SF reorientation. Disrupting localization of p21-activated kinase (PAK) did not prevent stretch-induced SF reorientation, suggesting that this Rac effector is not critical in regulating stretch-induced cytoskeletal remodeling. Overall, these results suggest that directional edge ruffling is not a primary mechanism that guides SF reorientation in response to stretch; the two events are coincident but not causal. PMID:25821527

  8. Impaired stretch modulation in potentially lethal cardiac sodium channel mutants.

    PubMed

    Banderali, Umberto; Juranka, Peter F; Clark, Robert B; Giles, Wayne R; Morris, Catherine E

    2010-01-01

    The presence of two slowly inactivating mutants of the cardiac sodium channel (hNa(V)1.5), R1623Q and R1626P, associate with sporadic Long-QT3 (LQT3) syndrome, and may contribute to ventricular tachyarrhythmias and/or lethal ventricular disturbances. Cardiac mechanoelectric feedback is considered a factor in such sporadic arrhythmias. Since stretch and shear forces modulate hNa(V)1.5 gating, detailed electrophysiological study of LQT-Na(V)1.5 mutant channel alpha subunit(s) might provide insights. We compared recombinant R1623Q and WT currents in control vs. stretched membrane of cell-attached patches of Xenopus oocytes. Macroscopic current was monitored before, during, and after stretch induced by pipette suction. In either mutant Na(+) channel, peak current at small depolarizations could be more than doubled by stretch. As in WT, R1623Q showed reversible and stretch intensity dependent acceleration of current onset and decay at all voltages, with kinetic coupling between these two processes retained during stretch. These two Na(V)1.5 channel alpha subunits differed in the absolute extent of kinetic acceleration for a given stretch intensity; over a range of intensities, R1623Q inactivation speed increased significantly less than did WT. The LQT3 mutant R1626P also retained its kinetic coupling during stretch. Whereas WT stretch-difference currents (I(Na)(V,t) without stretch minus I(Na)(V,t) with stretch) were mostly inhibitory (equivalent to outward current), they were substantially (R1623Q) or entirely (R1626P) excitatory for the LQT3 mutants. If stretch-modulated Na(V)1.5 current (i.e., brief excitation followed by accelerated current decay) routinely contributes to cardiac mechanoelectric feedback, then during hemodynamic load variations, the abnormal stretch-modulated components of R1623Q and R1626P current could be pro-arrhythmic.

  9. Curved Piezoelectric Actuators for Stretching Optical Fibers

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.

    2008-01-01

    Assemblies containing curved piezoceramic fiber composite actuators have been invented as means of stretching optical fibers by amounts that depend on applied drive voltages. Piezoceramic fiber composite actuators are conventionally manufactured as sheets or ribbons that are flat and flexible, but can be made curved to obtain load-carrying ability and displacement greater than those obtainable from the flat versions. In the primary embodiment of this invention, piezoceramic fibers are oriented parallel to the direction of longitudinal displacement of the actuators so that application of drive voltage causes the actuator to flatten, producing maximum motion. Actuator motion can be transmitted to the optical fiber by use of hinges and clamp blocks. In the original application of this invention, the optical fiber contains a Bragg grating and the purpose of the controlled stretching of the fiber is to tune the grating as part of a small, lightweight, mode-hop-free, rapidly tunable laser for demodulating strain in Bragg-grating strain-measurement optical fibers attached to structures. The invention could also be used to apply controllable tensile force or displacement to an object other than an optical fiber.

  10. Monte Carlo simulation of chromatin stretching

    NASA Astrophysics Data System (ADS)

    Aumann, Frank; Lankas, Filip; Caudron, Maïwen; Langowski, Jörg

    2006-04-01

    We present Monte Carlo (MC) simulations of the stretching of a single 30nm chromatin fiber. The model approximates the DNA by a flexible polymer chain with Debye-Hückel electrostatics and uses a two-angle zigzag model for the geometry of the linker DNA connecting the nucleosomes. The latter are represented by flat disks interacting via an attractive Gay-Berne potential. Our results show that the stiffness of the chromatin fiber strongly depends on the linker DNA length. Furthermore, changing the twisting angle between nucleosomes from 90° to 130° increases the stiffness significantly. An increase in the opening angle from 22° to 34° leads to softer fibers for small linker lengths. We observe that fibers containing a linker histone at each nucleosome are stiffer compared to those without the linker histone. The simulated persistence lengths and elastic moduli agree with experimental data. Finally, we show that the chromatin fiber does not behave as an isotropic elastic rod, but its rigidity depends on the direction of deformation: Chromatin is much more resistant to stretching than to bending.

  11. Stretched Exponential relaxation in pure Se glass

    NASA Astrophysics Data System (ADS)

    Dash, S.; Ravindren, S.; Boolchand, P.

    A universal feature of glasses is the stretched exponential relaxation, f (t) = exp[ - t / τ ] β . The model of diffusion of excitations to randomly distributed traps in a glass by Phillips1 yields the stretched exponent β = d[d +2] where d, the effective dimensionality. We have measured the enthalpy of relaxation ΔHnr (tw) at Tg of Se glass in modulated DSC experiments as glasses age at 300K and find β = 0.43(2) for tw in the 0

  12. Stretching DNA by a Constant Field

    NASA Astrophysics Data System (ADS)

    Hori, Yuko

    2005-03-01

    We consider the problem of stretching DNA by a constant field, such as an electric field or a hydrodynamic flow field. We obtain analytical expressions for the elongation of DNA under both weak and strong applied fields, in two and three dimensions. In the weak field limit we consider the effect of self-avoidance, which leads to a 9-fold enhancement of the average end-to-end distance over the result obtained when self-avoidance is ignored in two dimensions, and 3-fold increase in three dimensions. In the strong stretching regime we obtain the exact force-extension relation by mapping the problem to the Schrödinger equation for a simple harmonic oscillator in a time dependent potential. We use our theoretical results to comment on the experiment of Maier et al. ootnotetextB. Maier, U. Seifert, and J. O. Rä'dler, Europhys. Lett., 60, 622 (2002). on DNA adsorbed on a lipid bilayer in the presence of an in-plane electric field. In particular, we find that their estimate for the effective charge density of the DNA molecule, made on the basis of an approximate theory, requires significant corrections in light of our calculations. This work was supported by the NSF through grants DMR-9984471 and DMR-0403997. JK is a Cottrell Scholar of Research Corporation.

  13. Stretch sensors for human body motion

    NASA Astrophysics Data System (ADS)

    O'Brien, Ben; Gisby, Todd; Anderson, Iain A.

    2014-03-01

    Sensing motion of the human body is a difficult task. From an engineers' perspective people are soft highly mobile objects that move in and out of complex environments. As well as the technical challenge of sensing, concepts such as comfort, social intrusion, usability, and aesthetics are paramount in determining whether someone will adopt a sensing solution or not. At the same time the demands for human body motion sensing are growing fast. Athletes want feedback on posture and technique, consumers need new ways to interact with augmented reality devices, and healthcare providers wish to track recovery of a patient. Dielectric elastomer stretch sensors are ideal for bridging this gap. They are soft, flexible, and precise. They are low power, lightweight, and can be easily mounted on the body or embedded into clothing. From a commercialisation point of view stretch sensing is easier than actuation or generation - such sensors can be low voltage and integrated with conventional microelectronics. This paper takes a birds-eye view of the use of these sensors to measure human body motion. A holistic description of sensor operation and guidelines for sensor design will be presented to help technologists and developers in the space.

  14. Laminar and turbulent flow solutions with radiation and ablation injection for Jovian entry. [radiative heating rates for the Galileo probe

    NASA Technical Reports Server (NTRS)

    Kumar, A.; Tiwari, S. N.

    1980-01-01

    Laminar and turbulent flow-field solutions with coupled carbon-phenolic mass injection are presented for the forebody of a probe entering a nominal Jupiter atmosphere. Solutions are obtained for a 35-degree hyperboloid and for a 45-degree spherically blunted cone using a time-dependent, finite-difference method. The radiative heating rates for the coupled laminar flow are significantly reduced as compared to the corresponding no-blowing case; however, for the coupled turbulent flow, it is found that the surface radiative heating rates are substantially increased and often exceed the corresponding no-blowing values. Turbulence is found to have no effect on the surface radiative heating rates for the no-blowing solutions. The present results are compared with the other available solutions, and some additional solutions are presented.

  15. Simultaneous axial conduction in the fluid and the pipe wall for forced convective laminar flow with blowing and suction at the wall

    NASA Technical Reports Server (NTRS)

    Faghri, Amir; Chen, Ming-Ming; Mahefkey, E. T.

    1989-01-01

    Numerical solutions are reported for conjugate heat transfer in a porous pipe having an internal flow with blowing or suction at the inner surface of the pipe and constant heat flux at the outer surface. The effect of the simultaneous axial conduction through the wall and the fluid has been studied for the combined hydrodynamic and thermal entry lengths. The results show that the ratio of the thermal conductivities of the pipe wall to the fluid and the thickness of the pipe wall may become significant factors on the heat transfer when the Peclet number is small, especially for the case when fluid is injected into the pipe. It is also shown that the effect of axial wall conduction for the case of constant heat flux at the outer wall surface can be neglected when the wall thickness is small and the ratio of the conductivities of the wall to the fluid approaches unity.

  16. Experimental results of the control of a vortical flow by tangential blowing

    NASA Technical Reports Server (NTRS)

    Wood, N. J.; Roberts, L.

    1986-01-01

    The results of a wind tunnel test to investigate the controlling effects of tangential, leading edge blowing on the vortical flow over a delta wing are given. Blowing is used to directly control the crossflow separation points at the rounded leading edge and hence, the trajectory of the feeding sheet and the location of the vortex. Experiments were conducted for both co-flowing and counter-flowing configurations over a range of angles of attack from 0 to 90 degrees. Results in the form of pressure distributions, overall force coefficients and flow mappings were obtained. The emphasis is on data presentation rather than detailed analysis. The initial results indicate that the co-flowing configuration was capable of extending the regime of stable, controlled vortical flow over the upper surface by approximately 30 degrees angle of attack for modest blowing requirements. Increases in maximum normal force coefficient of approximately 30% were achieved and significant rolling moments produced at angles of attack from 30 to 60 degrees. The counter-flowing configuration indicated only minor lift augmentation with the exception of an isolated occurrence at 20 degrees angle of attack. At that condition, with very weak blowing, a lift augmentation of approximately 20 was measured.

  17. A Paradigm for Operant Conditioning in Blow Flies ("Phormia Terrae Novae" Robineau-Desvoidy, 1830)

    ERIC Educational Resources Information Center

    Sokolowski, Michel B. C.; Disma, Gerald; Abramson, Charles I.

    2010-01-01

    An operant conditioning situation for the blow fly ("Protophormia terrae novae") is described. Individual flies are trained to enter and reenter a hole as the operant response. Only a few sessions of contingent reinforcement are required to increase response rates. When the response is no longer followed by food, the rate of entering the hole…

  18. Straightforward factors for predicting the prognosis of blow-out fractures.

    PubMed

    Higashino, Takuya; Hirabayashi, Shinichi; Eguchi, Tomoaki; Kato, Yuki

    2011-07-01

    In blow-out fractures, some nonoperative cases have a poor outcome, and a method for accurate prognosis is required. To address this need, we retrospectively reviewed blow-out fractures presenting at Teikyo University Hospital between July 2004 and May 2007 and conducted a survey regarding diplopia and enophthalmos for nonoperative cases. Computed tomographic scan findings were divided according to fracture width and the degree of protrusion of the inferior rectus muscle into the maxillary sinus. We had 106 patients presenting with blow-out fractures, and 89 patients had been treated nonoperatively. In medial orbital wall fractures, no patient had diplopia, and 1 patient had enophthalmos after nonoperative treatment. In punched-out orbital floor fractures, all cases had diplopia when the fracture width was less than half the diameter of the globe, and the protrusion of the inferior rectus muscle into the maxillary sinus was half or more of its section. Even if the fracture width was less than half the diameter of the globe, 2 of 3 patients had enophthalmos when the protrusion of the inferior rectus muscle into the maxillary sinus was half or more of its section. Among the linear orbital floor fractures, 1 case required an emergency operation. We suggest a new algorithm for treatment of blow-out fractures based on computed tomographic scan findings that can also contribute to making a prognosis.

  19. Investigating influence of the magnetic arc blow in multi-break vacuum circuit breakers

    NASA Astrophysics Data System (ADS)

    Liao, Minfu; Ge, Guowei; Duan, Xiongying; Huang, Zhihui; Zou, Jiyan

    2016-12-01

    This paper investigates the influence of the interactive magnetic field in multi-break vacuum circuit breakers (VCBs) on the arc plasma and the post-arc characteristics. The magnetic field of multi-break VCBs is asymmetric and off-center because of the interactive magnetic field, which is also called bias magnetic field (BMF). The BMF distribution of double-break VCBs is gained by electromagnetic analysis. The test circuit of the magnetic arc blow in multi-break VCBs is established by simplifying as the interaction between the vacuum arc and the BMF. The influence of the magnetic arc blow on the arc plasma is studied by the high-speed CMOS camera and the post-arc current measure. While the vacuum arc is in the direction of the Ampere force with the BMF at 200 mT, it is in the retrograde direction when the BMF is below 100 mT, which results in the post-arc charge obviously varying from 9 μC to 50 μC. The relationship between the BMF and the post arc charge is gained. The mechanism of the magnetic arc blow in multi-break VCBs is discussed. Therefore, this paper can provide the base of construct and configuration to avoid the influence of the magnetic arc blow.

  20. Laboratory colonization of the blow flies, Chrysomya megacephala (Diptera: Calliphoridae) and Chrysomya rufifacies (Diptera: Calliphoridae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chrysomya rufifacies is a blow fly commonly found in corpses at crime scene investigations. This study was designed to develop laboratory colonization methods for Ch. rufifacies and utilize Chrysomya megacephala as its larval food source. Both fly species were collected in the wild and easily colon...

  1. Unsavory Problems at Tasty's: A Role-Play about Whistle-Blowing

    ERIC Educational Resources Information Center

    Comer, Debra R.; Vega, Gina

    2006-01-01

    This article presents a role-play exercise to make the topic of whistle-blowing personally salient to undergraduates. Students identify with the prospective whistle-blower, whose decision affects several stakeholders. The protagonist merely suspects her manager of stealing, until she hears concrete evidence of his thefts from her assistant…

  2. Whistle-Blowing as a Form of Advocacy: Guidelines for the Practitioner and Organization

    ERIC Educational Resources Information Center

    Greene, Annette D.; Latting, Jean Kantambu

    2004-01-01

    Advocacy has been an inherent component of social work since the mid-1800s. The NASW Code of Ethics explicitly promotes advocacy as an ethical stance against inhumane conditions. Whistle-blowing, on the other hand, occurs mostly in the business and public administration disciplines and is relatively unknown in the social work profession. Using…

  3. On the Blow-up Criterion of 3D-NSE in Sobolev-Gevrey Spaces

    NASA Astrophysics Data System (ADS)

    Benameur, Jamel; Jlali, Lotfi

    2016-12-01

    In Benameur (Methods Appl 103:87-97, 2014), Benameur proved a blow-up result of the non regular solution of ( NSE) in the Sobolev-Gevrey spaces. In this paper we improve this result, precisely we give an exponential type explosion in Sobolev-Gevrey spaces with less regularity on the initial condition. Fourier analysis and standard techniques are used.

  4. What Actions Can Be Taken to Increase Whistle-Blowing in the Classroom?

    ERIC Educational Resources Information Center

    Bernardi, Richard A.; Landry, Alexandra C.; Landry, Erynne E.; Buonafede, Mitchell R.; Berardi, Marissa E.

    2016-01-01

    This study surveyed undergraduate business students on various issues concerning the potential of students whistle-blowing when they observe other students cheating. Developing the courage of one's conviction in our accounting students is important to accounting educators as we are also emphasizing traits such as integrity, skepticism, and…

  5. Compressed Air System Modifications Improve Efficiency at a Plastics Blow Molding Plant (Southeastern Container Plant)

    SciTech Connect

    2001-06-01

    This case study is one in a series on industrial firms who are implementing energy efficient technologies and system improvements into their manufacturing processes. This case study documents the activities, savings, and lessons learned on the plastics blow molding plant project.

  6. Environmental factors affecting early carcass attendance by four species of blow flies (Diptera: Calliphoridae) in Texas.

    PubMed

    Mohr, Rachel M; Tomberlin, Jeffery K

    2014-05-01

    As the most common primary colonizer of carrion, adult blow flies (Diptera: Calliphoridae) play an important role in initiating arthropod-mediated breakdown of soft tissue; however, their timing is highly variable. This variability complicates the estimation of precolonization intervals or periods of insect activity by forensic entomologists. In this study, the size of the adult blow fly on swine carcasses was compared with various environmental conditions including time of day, temperature, wind speed, and light levels. Four trials were conducted: two in August and September 2008, one in January 2009, and one in February-March 2010. Of the measured variables, time of day was the only consistent factor explaining the population size of blow fly on a carcass, although precipitation and high winds affected winter-active Calliphora vicina Robineau-Desvoidy. Male flies were also collected, suggesting that carcasses may play additional roles in adult blow fly ecology beyond that of a simple oviposition site. For both sexes of flies, a strong diel pattern of behavior emerged, which could be useful in estimating precolonization intervals by considering the environmental conditions at a scene, and thus forensic entomologists may be better able to estimate the likelihood of adult activity at a carcass.

  7. Academic Misconduct: A Goals-Plans-Action Approach to Peer Confrontation and Whistle-Blowing

    ERIC Educational Resources Information Center

    Henningsen, Mary Lynn Miller; Valde, Kathleen S.; Denbow, Jessica

    2013-01-01

    Academic misconduct is a serious, pervasive, communication phenomenon on college campuses. In this study, the goals-plans-action model (Dillard, 1990) was used as a theoretical framework to investigate peer confrontation of cheating and whistle-blowing to a course instructor. In an experiment, participants were asked to respond to measures of…

  8. The American Economy: A Fuse About to Blow? Fundamentals of Free Enterprise, No. 6.

    ERIC Educational Resources Information Center

    American Fletcher National Bank and Trust Co., Indianapolis, IN.

    Designed for high school economics students as a public service project of the American Fletcher National Bank, the booklet examines the heavy burdens placed on our political-economic system and compares our economy to an overloaded electrical system about to "blow a fuse." In the last two decades, America has become a self-indulgent…

  9. BEARDSLEY AND PIPER (B&P) CORE BLOWING MACHINE. VIRGINIA BLAKELY MANUALLY ...

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

    BEARDSLEY AND PIPER (B&P) CORE BLOWING MACHINE. VIRGINIA BLAKELY MANUALLY FILLING SAND MAGAZINE THAT WILL ROTATE WITH THE CORE BOX, FILLING IT UNDER PRESSURE SIMILAR TO THE CORE MACHINE IN THE BACKGROUND. - Southern Ductile Casting Company, Core Making, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

  10. A Molecular Key for the Identification of Blow Flies in Southeastern Nebraska

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The identification of blow flies (Calliphoridae) (typically the first colonizers of cadavers) is difficult, especially in the earlier instars because of their small size, similarity and simplicity in external morphology. We consider how taxonomic keys based on molecular genetic data facilitate accur...

  11. Solution blow spun Poly(lactic acid)/Hydroxypropyl methylcellulose nanofibers with antimicrobial properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poly(lactic acid) (PLA) nanofibers containing hydroxypropyl methylcellulose (HPMC) and tetracycline hydrochloride (THC) were solution blow spun from two different solvents, chloroform/acetone (CA, 80:20 v/v) and 2,2,2-triflouroethanol (TFE). The diameter distribution, chemical, thermal, thermal stab...

  12. Effects of stretching the scalene muscles on slow vital capacity.

    PubMed

    Lee, Juncheol; Hwang, Sehee; Han, Seungim; Han, Dongwook

    2016-06-01

    [Purpose] The purpose of this study was to examine whether stretching of the scalene muscles would improve slow vital capacity (SVC). [Subjects and Methods] The subjects of this study were 20 healthy female students to whom the study's methods and purpose were explained and their agreement for participation was obtained. The SVC was measured using spirometry (Pony FX, COSMED Inc., Italy). The intervention used was stretching of the scalene muscles. Stretching was carried out for 15 min, 10 times at per each portion of scalene muscles: the anterior, middle, and posterior parts. [Results] Expiratory vital capacity (EVC) and tidal volume (Vt) noticeably increased after stretching. However, there were no changes in any of the SVC items in the control group. [Conclusion] This study demonstrated that stretching of the scalene muscles can effectively improve SVC. In particular, we confirmed that stretching of the scalene muscles was effective in increasing EVC and Vt, which are items of SVC.

  13. Effects of stretching the scalene muscles on slow vital capacity

    PubMed Central

    Lee, Juncheol; Hwang, Sehee; Han, Seungim; Han, Dongwook

    2016-01-01

    [Purpose] The purpose of this study was to examine whether stretching of the scalene muscles would improve slow vital capacity (SVC). [Subjects and Methods] The subjects of this study were 20 healthy female students to whom the study’s methods and purpose were explained and their agreement for participation was obtained. The SVC was measured using spirometry (Pony FX, COSMED Inc., Italy). The intervention used was stretching of the scalene muscles. Stretching was carried out for 15 min, 10 times at per each portion of scalene muscles: the anterior, middle, and posterior parts. [Results] Expiratory vital capacity (EVC) and tidal volume (Vt) noticeably increased after stretching. However, there were no changes in any of the SVC items in the control group. [Conclusion] This study demonstrated that stretching of the scalene muscles can effectively improve SVC. In particular, we confirmed that stretching of the scalene muscles was effective in increasing EVC and Vt, which are items of SVC. PMID:27390425

  14. Early modification of stretch reflex in Parkinson's disease.

    PubMed

    Bergui, M; Paglia, G; Lopiano, L; Quattrocolo, G; Bergamini, L; Bergamasco, B

    1993-07-01

    We stretched quadriceps femoris in healthy subjects and in patients with a recent diagnosis of PD in order to assess whether modifications of the long-latency component of the stretch reflex is an early event in the course of Parkinson's disease (PD). We found a modified mechanical and electromyographic (EMG) behavior in stretching relaxed muscles of patients while voluntary activation greatly reduced differences between normal and Parkinsonian subjects, suggesting that a lower threshold of the response is an early sign in PD.

  15. Effects of three different stretching techniques on vertical jumping performance.

    PubMed

    Kirmizigil, Berkiye; Ozcaldiran, Bahtiyar; Colakoglu, Muzaffer

    2014-05-01

    The aim of this study was to evaluate 3 different flexibility techniques: (a) ballistic stretching (BS), (b) proprioceptive neuromuscular facilitation stretching (PNF) + BS, and (c) PNF + static stretching (SS) on vertical jump (VJ) performance and to determine the most appropriate stretching method during warm-up period before explosive force disciplines. One hundred voluntary male athletes participated in this study. All subjects performed aerobic warm-up (5-minute jog) followed by BS (5 seconds for each stretching exercise), PNF + BS (PNF performed followed by 5 seconds of BS), and PNF + SS (PNF performed followed by 30 seconds of SS) treatment protocol, respectively in the same day. Each stretching treatment was applied for 4 sets bilaterally. In all stretching treatments, lumbar extensor, gluteus maximus, and hamstring muscles were stretched with a single stretching exercise. After a 2-minute brief rest period, participants performed 3 trials of VJ test followed by one of the treatment protocols. Vertical jump performance was evaluated by countermovement jump (CMJ). Participants were divided into 3 groups according to their flexibility and prejump performances after warm-up. For each individual group and the whole group, after all treatments, differences in CMJ values were obtained (p ≤ 0.05). Ballistic stretching increased the VJ performance in the groups with low and average flexibility, poor prejumping performance, and also in the whole group (p ≤ 0.05). Proprioceptive neuromuscular facilitation stretching + BS affected VJ performance in the group of participants with high flexibility (p ≤ 0.05). Proprioceptive neuromuscular facilitation + SS decreased VJ performance in groups of participants with high flexibility, moderate, and high prejumping performance and in whole group (p ≤ 0.05). Ballistic stretching method increased VJ height, therefore seems to be more suitable than PNF + SS and PNF + BS before events that rely on explosive power as a part

  16. Bi-soliton generation and its properties in stretched pulse fiber ring laser.

    PubMed

    Mao, Xuesong; Xiong, Ying; Ma, Yajie; Chen, Xiangcheng; Maruta, Akihiro

    2014-11-17

    We studied the formation of bi-soliton pairs in Kerr-type stretched pulse fiber ring laser (SPFRL). By solving the modified Ginzburg-Landau (GL) equaition, which models the SPFRL, we show that anti-phase bi-soliton can be generated robustly if a low level Gaussian pulse is injected into the ring laser in the initial set-up stage. With the help of properly selected high order nonlinear gain coefficient, the observation of anti-phase bi-soliton pairs is expected to become feasible in experiments.

  17. Enhancement of multispectral thermal infrared images - Decorrelation contrast stretching

    NASA Technical Reports Server (NTRS)

    Gillespie, Alan R.

    1992-01-01

    Decorrelation contrast stretching is an effective method for displaying information from multispectral thermal infrared (TIR) images. The technique involves transformation of the data to principle components ('decorrelation'), independent contrast 'stretching' of data from the new 'decorrelated' image bands, and retransformation of the stretched data back to the approximate original axes, based on the inverse of the principle component rotation. The enhancement is robust in that colors of the same scene components are similar in enhanced images of similar scenes, or the same scene imaged at different times. Decorrelation contrast stretching is reviewed in the context of other enhancements applied to TIR images.

  18. The Effects of Blowing Over Various Trailing-edge Flaps on an NACA 0006 Airfoil Section, Comparisons with Various Types of Flaps on other Airfoil Sections, and an Analysis of Flow and Power Relationships for Blowing Systems

    NASA Technical Reports Server (NTRS)

    Dods, J. B., Jr.; Watson, E. C.

    1976-01-01

    The results are presented of a two-dimensional investigation conducted to determine the effect of blowing over various types of trailing-edge flaps on a wing having the NACA 0006 airfoil section and a drooped-nose flap. The position and profile of the trailing-edge flap, the nozzle height, and the location of the flap with respect to the nozzle were found to be important variables. Data from many investigations were used to make an evaluation of the effects of blowing on lift. An analysis was made of flow and power relationships for blowing systems.

  19. Force fluctuations in stretching a tethered polymer

    NASA Astrophysics Data System (ADS)

    Varghese, Anoop; Vemparala, Satyavani; Rajesh, R.

    2013-08-01

    The recently proposed fluctuation relation in unfolding forces [Phys. Rev. E1539-375510.1103/PhysRevE.84.060101 84, 060101(R) (2011)] is reexamined taking into account the explicit time dependence of the force distribution. The stretching of a tethered Rouse polymer is exactly solved and the ratio of the probabilities of positive to negative forces is shown to be an exponential in force. Extensive steered molecular dynamics simulations of unfolding of deca alanine peptide confirm the form of fluctuation relation proposed earlier, but with explicit correct time dependence of unfolding forces taken into account. From exact calculations and simulations, a linear dependence of the constant in the exponential of the fluctuation relation on average unfolding forces and inverse temperature is proposed.

  20. Constellation Stretch Goals: Review of Industry Inputs

    NASA Technical Reports Server (NTRS)

    Lang, John

    2006-01-01

    Many good ideas received based on industry experience: a) Shuttle operations; b) Commercial aircraft production; c) NASA's historical way of doing business; d) Military and commercial programs. Aerospace performed preliminary analysis: a) Potential savings; b) Cost of implementation; c) Performance or other impact/penalties; d) Roadblocks; e) Unintended consequences; f) Bottom line. Significant work ahead for a "Stretch Goal"to become a good, documented requirement: 1) As a group, the relative "value" of goals are uneven; 2) Focused analysis on each goal is required: a) Need to ensure that a new requirement produces the desired consequence; b) It is not certain that some goals will not create problems elsewhere. 3) Individual implementation path needs to be studied: a) Best place to insert requirement (what level, which document); b) Appropriate wording for the requirement. Many goals reflect "best practices" based on lessons learned and may have value beyond near-term CxP requirements process.

  1. Stretched Lens Array Photovoltaic Concentrator Technology Developed

    NASA Technical Reports Server (NTRS)

    Piszczor, Michael F., Jr.; O'Neill, Mark J.

    2004-01-01

    Solar arrays have been and continue to be the mainstay in providing power to nearly all commercial and government spacecraft. Light from the Sun is directly converted into electrical energy using solar cells. One way to reduce the cost of future space power systems is by minimizing the size and number of expensive solar cells by focusing the sunlight onto smaller cells using concentrator optics. The stretched lens array (SLA) is a unique concept that uses arched Fresnel lens concentrators to focus sunlight onto a line of high-efficiency solar cells located directly beneath. The SLA concept is based on the Solar Concentrator Array with Refractive Linear Element Technology (SCARLET) design that was used on NASA's New Millennium Deep Space 1 mission. The highly successful asteroid/comet rendezvous mission (1998 to 2001) demonstrated the performance and long-term durability of the SCARLET/SLA solar array design and set the foundation for further improvements to optimize its performance.

  2. Aerothermodynamic properties of stretched flames in enclosures

    NASA Astrophysics Data System (ADS)

    Rotman, D. A.; Oppenheim, A. K.

    Flames are stretched by being pulled along their frontal surface by the flow field in which they reside. Their trajectories tend to approach particle paths, acquiring eventually the role of contact boundaries, -interfaces between the burnt and unburnt medium that may broaden solely as a consequence of diffusion. Fundamental properties of flow fields governing such flames are determined here on the basis of the zero Mach number model, providng a rational method of approach to the computational analysis of combustion fields in enclosures where, besides the aerodynamic properties flow, the thermodynamic process of compression must be taken into account. To illustrate its application, the method is used to reveal the mechanism of formation of a tulip-shape flame in a rectangular enclosure under nonturbulent flow conditions.

  3. Buckling and stretching of thin viscous sheets

    NASA Astrophysics Data System (ADS)

    O'Kiely, Doireann; Breward, Chris; Griffiths, Ian; Howell, Peter; Lange, Ulrich

    2016-11-01

    Thin glass sheets are used in smartphone, battery and semiconductor technology, and may be manufactured by producing a relatively thick glass slab and subsequently redrawing it to a required thickness. The resulting sheets commonly possess undesired centerline ripples and thick edges. We present a mathematical model in which a viscous sheet undergoes redraw in the direction of gravity, and show that, in a sufficiently strong gravitational field, buckling is driven by compression in a region near the bottom of the sheet, and limited by viscous resistance to stretching of the sheet. We use asymptotic analysis in the thin-sheet, low-Reynolds-number limit to determine the centerline profile and growth rate of such a viscous sheet.

  4. Understanding the Relative Flexibility of RNA and DNA Duplexes: Stretching and Twist-Stretch Coupling.

    PubMed

    Bao, Lei; Zhang, Xi; Shi, Ya-Zhou; Wu, Yuan-Yan; Tan, Zhi-Jie

    2017-03-28

    The flexibility of double-stranded (ds) RNA and dsDNA is crucial for their biological functions. Recent experiments have shown that the flexibility of dsRNA and dsDNA can be distinctively different in the aspects of stretching and twist-stretch coupling. Although various studies have been performed to understand the flexibility of dsRNA and dsDNA, there is still a lack of deep understanding of the distinctive differences in the flexibility of dsRNA and dsDNA helices as pertains to their stretching and twist-stretch coupling. In this work, we have explored the relative flexibility in stretching and twist-stretch coupling between dsRNA and dsDNA by all-atom molecular dynamics simulations. The calculated stretch modulus and twist-stretch coupling are in good accordance with the existing experiments. Our analyses show that the differences in stretching and twist-stretch coupling between dsRNA and dsDNA helices are mainly attributed to their different (A- and B-form) helical structures. Stronger basepair inclination and slide in dsRNA is responsible for the apparently weaker stretching rigidity versus that of dsDNA, and the opposite twist-stretch coupling for dsRNA and dsDNA is also attributed to the stronger basepair inclination in dsRNA than in dsDNA. Our calculated macroscopic elastic parameters and microscopic analyses are tested and validated by different force fields for both dsRNA and dsDNA.

  5. Effects of stretching on upper-body muscular performance.

    PubMed

    Torres, Earlando M; Kraemer, William J; Vingren, Jakob L; Volek, Jeff S; Hatfield, Disa L; Spiering, Barry A; Ho, Jen Yu; Fragala, Maren S; Thomas, Gwendolyn A; Anderson, Jeffrey M; Häkkinen, Keijo; Maresh, Carl M

    2008-07-01

    The purpose of this investigation was to examine the influence of upper-body static stretching and dynamic stretching on upper-body muscular performance. Eleven healthy men, who were National Collegiate Athletic Association Division I track and field athletes (age, 19.6 +/- 1.7 years; body mass, 93.7 +/- 13.8 kg; height, 183.6 +/- 4.6 cm; bench press 1 repetition maximum [1RM], 106.2 +/- 23.0 kg), participated in this study. Over 4 sessions, subjects participated in 4 different stretching protocols (i.e., no stretching, static stretching, dynamic stretching, and combined static and dynamic stretching) in a balanced randomized order followed by 4 tests: 30% of 1 RM bench throw, isometric bench press, overhead medicine ball throw, and lateral medicine ball throw. Depending on the exercise, test peak power (Pmax), peak force (Fmax), peak acceleration (Amax), peak velocity (Vmax), and peak displacement (Dmax) were measured. There were no differences among stretch trials for Pmax, Fmax, Amax, Vmax, or Dmax for the bench throw or for Fmax for the isometric bench press. For the overhead medicine ball throw, there were no differences among stretch trials for Vmax or Dmax. For the lateral medicine ball throw, there was no difference in Vmax among stretch trials; however, Dmax was significantly larger (p stretching on upper-body muscular performance in young adult male athletes, regardless of stretch mode, potentially due to the amount of rest used after stretching before the performances. Since throwing performance was largely unaffected by static or dynamic upper-body stretching, athletes competing in the field events could perform upper-body stretching, if enough time were allowed before the performance. However, prior studies on lower-body musculature have demonstrated dramatic negative effects on speed and power. Therefore, it is

  6. Synergistic Separation Behavior of Boron in Metallurgical Grade Silicon Using a Combined Slagging and Gas Blowing Refining Technique

    NASA Astrophysics Data System (ADS)

    Wu, Jijun; Zhou, Yeqiang; Ma, Wenhui; Xu, Min; Yang, Bin

    2017-02-01

    A combined slagging and gas blowing refining technique for boron removal from metallurgical grade silicon using the CaO-SiO2-CaCl2 slag and the mixed Ar-O2-H2O gas is investigated. The oxygen gas blowing in combination with water vapor shows a wonderful removal efficiency of boron compared with the single oxygen or the single water vapor blowing. It is analyzed from the thermodynamics that a synergistic separation behavior of boron is resulted from CaCl2 and O2. Boron is removed and reduced from 22 to 0.75 ppmw with a removal efficiency of 96.6 pct.

  7. On the blow-up phenomena of solutions for the full compressible Euler equations in {{{R}}^{N}}

    NASA Astrophysics Data System (ADS)

    Wu, Xinglong

    2016-11-01

    In fluid dynamics, blow-up phenomena of solutions is interesting and challenging to physicists and mathematicians. The present paper is devoted to studying blow-up phenomena of the spherically symmetric solutions for the full compressible Euler equations in {{{R}}N}, N≥slant 1 . The approach is to a construct special explicit solution with spherical symmetry to study certain blow-up phenomena of solutions to the full compressible Euler equation in {{{R}}N} . We also discuss steady-state smooth solutions of spherical symmetry to equation (1.1).

  8. Stagnation point flow, heat transfer and species transfer over a shrinking sheet with coupled Stefan blowing effects from species transfer

    NASA Astrophysics Data System (ADS)

    Hamid, Rohana Abdul; Nazar, Roslinda; Pop, Ioan

    2016-11-01

    The problem of stagnation-point flow and heat transfer with the effect of the blowing from species transfer over an impermeable shrinking sheet is studied. The governing boundary layer equations are transformed into the ordinary differential equations using the similarity transformations which are then solved numerically using the bvp4c function in Matlab. The focus of this study is the effect of the blowing parameter to the velocity of the flow, the rate of heat transfer and the mass of species transfer over a flat surface of shrinking sheet. From the numerical results, it is found that the blowing parameter substantially affects the flow, heat and mass transfer characteristics.

  9. Nitrogen addition using a gas blow in an ESR process

    NASA Astrophysics Data System (ADS)

    Yamamoto, S.; Momoi, Y.; Kajikawa, K.

    2016-07-01

    A new nitrogen method for adding in an ESR process using nitrogen gas blown in through the electrode was investigated. Nitrogen gas blown through a center bore of the electrode enabled contact between the nitrogen gas and the molten steel directly underneath the electrode tip. A ɸ 145mm diameter, laboratory-sized PESR furnace was used for the study on the reaction kinetics. Also, we carried out a water-model experiment in order to check the injection depth of the gas blown in the slag. The water model showed that the gas did not reach the upper surface of the molten metal and flowed on the bottom surface of the electrode only. An EPMA was carried out for a droplet remaining on the tip of the electrode after melting. The molten steel from the tip of the electrode shows that nitrogen gas absorption occurred at the tip of the electrode. The mass transfer coefficient was around 1.0x10-2 cm/sec in the system. This value is almost the same as the coefficient at the molten steel free surface.

  10. Effect of participants' static stretching knowledge or deception on the responses to prolonged stretching.

    PubMed

    Janes, W C Ian; Snow, Brandon B G; Watkins, Caisie E; Noseworthy, Elecia A L; Reid, Jonathan C; Behm, David G

    2016-10-01

    Much of the static stretching (SS) literature reports performance impairments with prolonged SS. However, it has been acknowledged that a limitation of these studies is participants' knowledge or bias. Since many participants have knowledge of the literature, their performance may be subconsciously influenced by expectations. Hence, the objective of this study was to examine the effect of stretching knowledge or deception on subsequent force output following SS. Two groups of male participants who were either aware (BIASED: 14) or unaware (DECEPTION: 14) of the SS literature participated. Unaware participants were misinformed that SS increases force production. Testing involved maximal voluntary isometric contractions (MVC) of the quadriceps and hamstrings at pre-, post-, and 5 min post-intervention (three 30-s passive hamstring stretches to the point of discomfort with 30-s rest intervals) or control. While the DECEPTION group displayed impaired knee flexion force (p = 0.04; 3.6% and 10.4%) following hamstrings SS, there was no significant impairment with the BIASED (-1.1% and +0.9%) group. Both groups exhibited hamstrings F200 (force produced in the first 200 ms) impairments following SS. Whereas BIASED participants exhibited an overall decrease (p < 0.05; 1.8% and 4.2%) in knee extension MVC, DECEPTION participants showed (p = 0.005; 8.8% and 5.1%) force increases. The quadriceps F200 was not significantly affected with the BIASED group but overall there were 4.5% and 8.7% F200 impairments at 1 and 5 min post-intervention (p = 0.05) with the DECEPTION group. Thus while deception resulted in enhanced quadriceps muscle force output, there was no knowledge or deception advantage when stretching the hamstrings.

  11. Single-stage evaluation of highly-loaded high-Mach-number compressor stages 5. Data and performance of baseline, corner-blow wall suction and combined corner blow wall suction stator

    NASA Technical Reports Server (NTRS)

    Nikkanen, J. P.; Brooky, J. P.

    1972-01-01

    A single-stage compressor with a rotor tip speed of 1600 ft/sec and a 0.5 hub tip ratio was used to investigate the effects of several stator endwall treatment methods on stage range and performance. These endwall treatment methods consisted of stator corner-blow, annular wall suction upstream of stator leading edge, and combined corner-blow and annular wall suction. The overall stage performance with corner blow was essentially the same as the baseline performance. The performance for the annular wall suction and the combined corner-blow and wall suction showed a reduction in peak efficiency of 2.5 percentage points compared to the baseline data.

  12. The stretch reflex and the contributions of C David Marsden

    PubMed Central

    Bhattacharyya, Kalyan B.

    2017-01-01

    The stretch reflex or myotatic reflex refers to the contraction of a muscle in response to its passive stretching by increasing its contractility as long as the stretch is within physiological limits. For ages, it was thought that the stretch reflex was of short latency and it was synonymous with the tendon reflex, subserving the same spinal reflex arc. However, disparities in the status of the two reflexes in certain clinical situations led Marsden and his collaborators to carry out a series of experiments that helped to establish that the two reflexes had different pathways. That the two reflexes are dissociated has been proved by the fact that the stretch reflex and the tendon reflex, elicited by stimulation of the same muscle, have different latencies, that of the stretch reflex being considerably longer. They hypothesized that the stretch reflex had a transcortical course before it reached the spinal motor neurons for final firing. Additionally, the phenomenon of stimulus-sensitive cortical myoclonus lent further evidence to the presence of the transcortical loop where the EEG correlate preceded the EMG discharge. This concept has been worked out by later neurologists in great detail, and the general consensus is that indeed, the stretch reflex is endowed with a conspicuous transcortical component. PMID:28298835

  13. The stretch reflex and the contributions of C David Marsden.

    PubMed

    Bhattacharyya, Kalyan B

    2017-01-01

    The stretch reflex or myotatic reflex refers to the contraction of a muscle in response to its passive stretching by increasing its contractility as long as the stretch is within physiological limits. For ages, it was thought that the stretch reflex was of short latency and it was synonymous with the tendon reflex, subserving the same spinal reflex arc. However, disparities in the status of the two reflexes in certain clinical situations led Marsden and his collaborators to carry out a series of experiments that helped to establish that the two reflexes had different pathways. That the two reflexes are dissociated has been proved by the fact that the stretch reflex and the tendon reflex, elicited by stimulation of the same muscle, have different latencies, that of the stretch reflex being considerably longer. They hypothesized that the stretch reflex had a transcortical course before it reached the spinal motor neurons for final firing. Additionally, the phenomenon of stimulus-sensitive cortical myoclonus lent further evidence to the presence of the transcortical loop where the EEG correlate preceded the EMG discharge. This concept has been worked out by later neurologists in great detail, and the general consensus is that indeed, the stretch reflex is endowed with a conspicuous transcortical component.

  14. A Stretching Device for High Resolution Live-Cell Imaging

    PubMed Central

    Huang, Lawrence; Mathieu, Pattie S.; Helmke, Brian P.

    2012-01-01

    Several custom-built and commercially available devices are available to investigate cellular responses to substrate strain. However, analysis of structural dynamics by microscopy in living cells during stretch is not readily feasible. We describe a novel stretch device optimized for high-resolution live-cell imaging. The unit assembles onto standard inverted microscopes and applies constant magnitude or cyclic stretch at physiological magnitudes to cultured cells on elastic membranes. Interchangeable modular indenters enable delivery of equibiaxial and uniaxial stretch profiles. Strain analysis performed by tracking fluorescent microspheres adhered onto the substrate demonstrated reproducible application of stretch profiles. In endothelial cells transiently expressing EGFP-vimentin and paxillin-DsRed2 and subjected to constant magnitude equibiaxial stretch, the 2-D strain tensor demonstrated efficient transmission through the extracellular matrix and focal adhesions. Decreased transmission to the intermediate filament network was measured, and a heterogeneous spatial distribution of maximum stretch magnitude revealed discrete sites of strain focusing. Spatial correlation of vimentin and paxillin displacement vectors provided an estimate of the extent of mechanical coupling between the structures. Interestingly, switching the spatial profile of substrate strain reveals that actin-mediated edge ruffling is not desensitized to repeated mechano-stimulation. These initial observations show that the stretch device is compatible with live-cell microscopy and is a novel tool for measuring dynamic structural remodeling under mechanical strain. PMID:20195762

  15. Does Postexercise Static Stretching Alleviate Delayed Muscle Soreness?

    ERIC Educational Resources Information Center

    Buroker, Katherine C.; Schwane, James A.

    1989-01-01

    Because many experts recommend stretching after exercise to relieve muscle soreness, 23 subjects performed a 30-minute step test to induce delayed muscle soreness. There was neither temporary relief of pain immediately after stretching nor a reduction in pain during the 3-day postexercise period. (Author/SM)

  16. The history dependence of force production in mammalian skeletal muscle following stretch-shortening and shortening-stretch cycles.

    PubMed

    Herzog, W; Leonard, T R

    2000-05-01

    The purpose of this study was to determine the history dependence of force production during and following stretch-shortening and shortening-stretch cycles in mammalian skeletal muscle. Thirty-three different isometric, stretch, shortening, stretch-shortening and shortening-stretch experiments were preformed in cat soleus (n=8) using previously established methods. Stretch-shortening and shortening-stretch cycles are not commutative with respect to the isometric forces following the length changes. Whereas force depression following shortening is virtually unaffected by previous stretching of the muscle, force enhancement following stretch depends in a dose-dependent manner on the amount of muscle shortening preceding the stretch. The history dependence of isometric force following shortening-stretch cycles can conveniently be modelled using an elastic (compressive and tensile) element that engages at the length of muscle activation. Such an "elastic" mechanism has been proposed by Edman and Tsuchiya (1996) (Edman, K.A. P., Tsuchiya, T., 1996. Strain of passive elements during force enhancement by stretch in frog mucle fibres. Journal of Physiology 490. 1, 191-205) based on experimental observations, and has been implemented theoretically in a rheological model of muscle (Forcinito et al., 1997) (Forcinito, M., Epstein, M., Herzog, W., 1997. Theoretical considerations on myofibril stiffness. Biophysics Journal 72, 1278-1286). The history dependence of isometric force following stretch-shortening cycles appears independent of the stretch preceding the shortening, except perhaps, if stretching occurs at very high speeds (i.e. 6-10 times fibre length per second). The results of this study are hard to reconcile with the two major mechanisms associated with history dependence of force production: sarcomere length non-uniformity (Edman et al., 1993) and stress-induced cross-bridge inhibition (Maréchal and Plaghki, 1979) (Maréchal, G., Plaghki, L., 1979. The deficit of

  17. Bruxism: Is There an Indication for Muscle-Stretching Exercises?

    PubMed

    Gouw, Simone; de Wijer, Anton; Creugers, Nico Hj; Kalaykova, Stanimira I

    Bruxism is a common phenomenon involving repetitive activation of the masticatory muscles. Muscle-stretching exercises are a recommended part of several international guidelines for musculoskeletal disorders and may be effective in management of the jaw muscle activity that gives rise to bruxism. However, most studies of muscle-stretching exercises have mainly focused on their influence on performance (eg, range of motion, coordination, and muscle strength) of the limb or trunk muscles of healthy individuals or individuals with sports-related injuries. Very few have investigated stretching of the human masticatory muscles and none muscle-stretching exercises in the management of (sleep) bruxism. This article reviews the literature on muscle-stretching exercises and their potential role in the management of sleep bruxism or its consequences in the musculoskeletal system.

  18. Flows induced by exponential stretching and shearing plate motions

    NASA Astrophysics Data System (ADS)

    Weidman, Patrick

    2016-11-01

    Boundary-layer solutions for the flow induced by an exponentially stretching surface also sheared in its own plane are given. Prior to this study no similarity solutions have been reported for flows generated by exponentially sheared surfaces concomitant with surface stretching in any form. The method of solution is self-similarity. The results found here are intimately related to those of Magyari and Keller ["Heat and mass transfer in the boundary layers on an exponentially stretching continuous surface," J. Phys. D: Appl. Phys. 32, 577-585 (1999)] who studied the motion and heat transfer induced by an exponentially stretching plate. In addition to two particular cases reported here, a third situation is found where an exponentially stretching surface admits a concomitant arbitrary streamwise shearing motion.

  19. Flow of viscous fluid along a nonlinearly stretching curved surface

    NASA Astrophysics Data System (ADS)

    Sanni, K. M.; Asghar, S.; Jalil, M.; Okechi, N. F.

    This paper focuses on the flow of viscous fluid over a curved surface stretching with nonlinear power-law velocity. The boundary layer equations are transformed into ordinary differential equations using suitable non-dimensional transformations. These equations are solved numerically using shooting and Runge-Kutta (RK) methods. The impact of non-dimensional radius of curvature and power-law indices on the velocity field, the pressure and the skin friction coefficient are investigated. The results deduced for linear stretching are compared with the published work to validate the numerical procedure. The important findings are: (a) Slight variation of the curvature of the stretching sheet increases the velocity and the skin friction coefficient significantly. (b) The nonlinearity of the stretching velocity increases the skin friction. (c) The results for linear stretching and the flat surface are the special cases of this problem.

  20. Stretching and injury prevention in football: current perspectives.

    PubMed

    Stojanovic, Marko D; Ostojic, Sergej M

    2011-04-01

    Stretching exercises are regularly recommended as a part of football-training sessions and in preparation for competition. There is little sound empirical evidence, however, to substantiate the role of stretching exercises and consequently increased flexibility on injury prevention in football. Furthermore, in the last decade or so, fundamental research has shed some light on the biomechanical adaptation of the muscle-tendon unit following different stretching protocols, improving knowledge about the topic and enabling better understanding of the stretching-injury relationship. The purpose of this review is to examine the literature on the role of stretching and/or increased flexibility on injury prevention in football, with presented results analyzed in the context of the up-to-date basic science research evidence.

  1. Dielectrophoretic Stretching of DNA Tethered to a Fiber Tip

    PubMed Central

    Hyun, Changbae; Kaur, Harpreet; McNabb, David S.; Li, Jiali

    2015-01-01

    In this work, we studied the stretching of λ phage DNA molecules immobilized on an optical fiber tip attached to a force sensitive tuning fork under AC electric fields. We designed a two electrodes stretching system in a small chamber: one is a gold-coated optical fiber tip electrode, and the other is a gold-coated flat electrode. By applying a dielectrophoretic force, the immobilized λ DNA molecules on the tip are stretched and the stretching process is monitored by a fluorescent microscope. The DNA stretching in three-dimensional space is optimized by varying electrode shape, electrode gap distance, AC frequency, and solution conductivity. By observing the vibrational amplitude change of a quartz tuning fork, we measured the effects due to Joule heating and the dielectrophoretic force on the tethered DNA molecules in solution. This work demonstrates a method to manipulate and characterize immobilized λ DNA molecules on a probe tip for further study of single DNA molecules. PMID:25741602

  2. A Comparison Study of the Oxygen-Rich Side Blow Furnace and the Oxygen-Rich Bottom Blow Furnace for Liquid High Lead Slag Reduction

    NASA Astrophysics Data System (ADS)

    Chen, Lin; Hao, Zhandong; Yang, Tianzu; Liu, Weifeng; Zhang, Duchao; Zhang, Li; Bin, Shu; Bin, Wanda

    2015-05-01

    This work investigates the characteristics of the oxygen-rich side blow furnace (OSBF) and the oxygen-rich bottom blow furnace (OBBF) as the reductive smelting reactor for molten high lead slag. The slags were collected from different sampling points of these furnaces during a regular high lead slag reduction process and analyzed. It is disclosed that lead content of the melt in the OSBF shows dramatic fluctuations, while melt from different sampling points of the furnace behave similarly, exhibiting the characteristics of batch reactor. An obvious axial lead content gradient is detected in the OBBF, showing the characteristics of a plug flow reactor. The industrial performances of these furnaces are also compared. The results indicate that 1.38% higher lead recovery can be achieved by using the OSBF instead of the OBBF. Unit energy consumptions of the OBBF-OSBF and OBBF-OBBF processes can be reduced to 230 kgce/ t crude lead, which is 70 kgce/ t crude lead less than that of the tradition Shuikoushan (SKS) process.

  3. Pre-exercise stretching does not impact upon running economy.

    PubMed

    Hayes, Philip R; Walker, Adrian

    2007-11-01

    Pre-exercise stretching has been widely reported to reduce performance in tasks requiring maximal or near-maximal force or torque. The purpose of this study was to compare the effects of 3 different pre-exercise stretching routines on running economy. Seven competitive male middle and long-distance runners (mean +/- SD) age: 32.5 +/- 7.7 years; height: 175.0 +/- 8.8 cm; mass: 67.8 +/- 8.6 kg; V(.-)O2max: 66.8 +/- 7.0 ml x kg(-1) x min(-1)) volunteered to participate in this study. Each participant completed 4 different pre-exercise conditions: (a) a control condition, (b) static stretching, (c) progressive static stretching, and (d) dynamic stretching. Each stretching routine consisted of 2 x 30-second stretches for each of 5 exercises. Dependent variables measured were sit and reach test before and after each pre-exercise routine, running economy (ml x kg(-1) x km(-1)), and steady-state oxygen uptake (ml x kg(-1) x min(-1)), which were measured during the final 3 minutes of a 10-minute run below lactate threshold. All 3 stretching routines resulted in an increase in the range of movement (p = 0.008). There was no change in either running economy (p = 0.915) or steady-state V(.-)O2 (p = 0.943). The lack of change in running economy was most likely because it was assessed after a period of submaximal running, which may have masked any effects from the stretching protocols. Previously reported reductions in performance have been attributed to reduced motor unit activation, presumably IIX. In this study, these motor units were likely not to have been recruited; this may explain the unimpaired performance. This study suggests that pre-exercise stretching has no impact upon running economy or submaximal exercise oxygen cost.

  4. Gene expression during blow fly development: improving the precision of age estimates in forensic entomology.

    PubMed

    Tarone, Aaron M; Foran, David R

    2011-01-01

    Forensic entomologists use size and developmental stage to estimate blow fly age, and from those, a postmortem interval. Since such estimates are generally accurate but often lack precision, particularly in the older developmental stages, alternative aging methods would be advantageous. Presented here is a means of incorporating developmentally regulated gene expression levels into traditional stage and size data, with a goal of more precisely estimating developmental age of immature Lucilia sericata. Generalized additive models of development showed improved statistical support compared to models that did not include gene expression data, resulting in an increase in estimate precision, especially for postfeeding third instars and pupae. The models were then used to make blind estimates of development for 86 immature L. sericata raised on rat carcasses. Overall, inclusion of gene expression data resulted in increased precision in aging blow flies.

  5. Navier-Stokes computation of wing leading edge tangential blowing for a tilt rotor in hover

    NASA Technical Reports Server (NTRS)

    Fejtek, Ian; Roberts, Leonard

    1992-01-01

    The effect of a thin tangential jet located at the leading edge of the wing of a tilt rotor configuration in hover is computed using the thin-layer Navier-stokes equations. Computations showed that leading edge tangential blowing is effective in reducing the download caused by the impingement of the rotor download caused by the impingement of the rotor downwash on the wing. Results from the numerical model support previous experimental findings that download reduction is due mainly to a decrease in upper surface pressure and not an increase in pressure on the lower surface. The numerical solution clearly shows that because of the three-dimensionality of the flow field, the download could be reduced further by allowing a spanwise variation in blowing strength.

  6. Effect of a simulated engine jet blowing above an arrow wing at Mach 2.0

    NASA Technical Reports Server (NTRS)

    Shrout, B. L.; Hayes, C.

    1977-01-01

    The effects of a gas jet simulating a turbojet engine exhaust blowing above a cambered and twisted arrow wing were investigated. Tests were conducted in the Langley 4-foot supersonic pressure tunnel at a Mach number of 2.0. Nozzle pressure ratios from 1 to 64 were tested with both helium and air used as jet gases. The tests were conducted at angles of attack from -2 deg to 8 deg at a Reynolds number of 9,840,000 per meter. Only the forces and moments on the wing were measured. Results of the investigation indicated that the jet blowing over the wing caused reductions in maximum lift-drag ratio of about 4 percent for helium and 6 percent for air at their respective design nozzle pressure ratios, relative to jet-off data. Moderate changes in the longitudinal, vertical, or angular positions of the jet relative to the wing had little effect on the wing aerodynamic characteristics.

  7. Critical air/water blow-down in safety valves at low qualities.

    PubMed

    Moncalvo, D; Friedel, L

    2011-02-28

    Critical air/water blow-downs in safety valves for qualities from 0.01 to 0.113 and mass flow rates from 1.5 up to 4.3 kg/s have been observed in our test facility. These critical blow-downs are characterized by a large void fraction and by an intense mixing of the phases both in the valve body and in the outlet pipe. A qualitative estimation of the flow pattern in the outlet pipe using the map of Taitel and Dukler suggests that these air/water flows are intermittent flows--presumably slug flows--evolving to annular flows for qualities above 0.1. Intermittent flows are also predicted for critical air/water and air/glycerine flows taken from the literature for the same safety valve at slightly larger relieving pressures.

  8. Experimental Evaluation of the Penalty Associated With Micro-Blowing for Reducing Skin Friction

    NASA Technical Reports Server (NTRS)

    Hwang, Danny P.; Biesiadny, Tom J.

    1997-01-01

    A micro-blowing technique (MBT) experiment was conducted in the Advanced Nozzle and Engine Components Test Facility at the NASA Lewis Research Center. The objectives of the test were to evaluate the pressure-drag penalty associated with the MBT and to provide additional information about the porous plates used for micro-blowing. The results showed that 1 of 12 plates tested could reduce the total drag (skin-friction drag plus pressure drag) below a solid flat plate value. The results of this experiment and prior data showed that a total drag reduction below a solid flat plate value was possible. More tests are needed to find an optimal MBT skin and to find a technique to reduce pressure drag.

  9. Investigation of trailing-edge-flap, spanwise-blowing concepts on an advanced fighter configuration

    NASA Technical Reports Server (NTRS)

    Paulson, J. W., Jr.; Quinto, P. F.; Banks, D. W.

    1984-01-01

    The aerodynamic effects of spanwise blowing on the trailing edge flap of an advanced fighter aircraft configuration were determined in the 4 by 7 Meter Tunnel. A series of tests were conducted with variations in spanwise-blowing vector angle, nozzle exit area, nozzle location, thrust coefficient, and flap deflection in order to determine a superior configuration for both an underwing cascade concept and an overwing port concept. This screening phase of the testing was conducted at a nominal approach angle of attack from 12 deg to 16 deg; and then the superior configurations were tested over a more complete angle of attack range from 0 deg to 20 deg at tunnel free stream dynamic pressures from 20 to 40 lbf/sq ft at thrust coefficients from 0 to 2.

  10. RDX and TNT residues from live-fire and blow-in-place detonations.

    PubMed

    Hewitt, Alan D; Jenkins, Thomas F; Walsh, Marianne E; Walsh, Michael R; Taylor, Susan

    2005-11-01

    Snow was used as a collection medium to examine 1,3,5-hexahydro-1,3,5-trinitrotriazine (RDX) and 2,4,6-trinitrotoluene (TNT) residues post-detonation of 60-, 81-, and 120-mm mortar rounds, 105- and 155-mm howitzer rounds, M67 hand grenades, 40-mm rifle grenades, and blocks of C4. Residue-covered snow samples were collected, processed, and analyzed for explosives without cross-contamination from previous detonations and other potential matrix interferences. Detonation trials were performed following standard military live-fire and blow-in-place techniques. When possible, replicate munitions were detonated under similar conditions to provide a more reliable estimation of the mass of unconsumed high explosive residues. Overall the amount of energetic residues deposited from live-fire detonations were considerably less than the energetic residues deposited by blow-in-place detonations.

  11. Simulation on the Effect of Bottle Wall Thickness Distribution using Blow Moulding Technique

    NASA Astrophysics Data System (ADS)

    Suraya, S.; Azman, M. D.; Fatchurrohman, N.; Jaafar, A. A.; Yusoff, A. R.

    2016-02-01

    The aims of this study are to assess the deformation behavior of a polymeric material during a blow moulding process. Transient computations of two dimensional model of a PP bottle were performed using ANSYS Polyflow computer code to predict the wall thickness distribution at four different parison's diameter; 8mm, 10mm, 18mm, and 20mm. Effects on the final wall thickness diameter and time step are studied. The simulated data shows that the inflation performance degrades with increasing parison diameter. It is concluded that the blow moulding process using 10mm parison successfully meet the product processing requirements. Factors that contribute to the variation in deformation behaviour of the plastic during the manufacturing process are discussed.

  12. Identities for Generalized Appell Functions and the Blow-up Formula

    NASA Astrophysics Data System (ADS)

    Bringmann, Kathrin; Manschot, Jan; Rolen, Larry

    2016-10-01

    In this paper, we prove identities for a class of generalized Appell functions which are based on the {A_2} root lattice. The identities are reminiscent of periodicity relations for the classical Appell function and are proven using only analytical properties of the functions. Moreover, they are a consequence of the blow-up formula for generating functions of invariants of moduli spaces of semi-stable sheaves of rank 3 on rational surfaces. Our proof confirms that in the latter context, different routes to compute the generating function (using the blow-up formula and wall-crossing) do arrive at identical q-series. The proof also gives a clear procedure on how to prove analogous identities for generalized Appell functions appearing in generating functions for sheaves with rank {r>3}.

  13. Methanogenic Blow-up in the End-Permian Carbon Cycle

    NASA Astrophysics Data System (ADS)

    Rothman, D.; Fournier, G.; French, K. L.; Alm, E.; Boyle, E. A.; Cao, C.; Summons, R. E.

    2012-12-01

    The end-Permian extinction is associated with a mysterious disruption to Earth's carbon cycle. Here we identify causal mechanisms via three observations. First, we show that geochemical signals indicate an incipient singular blow-up of the marine inorganic carbon reservoir, coincident with the extinction and consistent with the evolutionary expansion of a new microbial metabolic pathway. Second, we show that the fast acetoclastic pathway in Methanosarcina, limited by nickel and responsible for most modern biogenic methane, emerged at a time statistically indistinguishable from the extinction. Finally, we show that nickel concentrations in South China sediments increased sharply at the extinction, probably as a consequence of massive Siberian volcanism and enabling the blow-up. Collectively, these results suggest that a specific microbial innovation instigated Earth's greatest mass extinction.

  14. An electrostatic charge measurement of blowing snow particles focusing on collision frequency to the snow surface

    NASA Astrophysics Data System (ADS)

    Omiya, S.; Sato, A.

    2010-12-01

    Blowing snow particles are known to have an electrostatic charge. This charge may be a contributing factor in the formation of snow drifts and snow cornices and changing of the trajectory of blowing snow particles. These formations and phenomena can cause natural disaster such as an avalanche and a visibility deterioration, and obstruct transportation during winter season. Therefore, charging phenomenon of the blowing snow particles is an important issue in terms of not only precise understanding of the particle motion but disaster prevention. The primary factor of charge accumulation to the blowing snow particles is thought to be due to “saltation” of them. The “saltation” is one of movement forms of blowing snow: when the snow particles are transported by the wind, they repeat frictional collisions with the snow surface. In previous studies, charge-to-mass ratios measured in the field were approximately -50 to -10 μC/kg, and in the wind tunnel were approximately -0.8 to -0.1 μC/kg. While there were qualitatively consistent in sign, negative, there were huge gaps quantitatively between them. One reason of those gaps is speculated to be due to differences in fetch. In other words, the difference of the collision frequency of snow particles to the snow surface has caused the gaps. But it is merely a suggestion and that has not been confirmed. The purpose of this experiment is to measure the charge of blowing snow particles focusing on the collision frequency and clarify the relationship between them. Experiments were carried out in the cryogenic wind tunnel of Snow and Ice Research Center (NIED, JAPAN). A Faraday cage and an electrometer were used to measure the charge of snow particles. These experiments were conducted over the hard snow surface condition to prevent the erosion of the snow surface and the generation of new snow particles from the surface. The collision frequency of particle was controlled by changing the wind velocity (4.5 to 7 m/s) under

  15. High-Lift Capability of Low Aspect Ratio Wings Utilizing Circulation Control and Upper Surface Blowing

    DTIC Science & Technology

    1980-07-01

    the Upper Surface Blowing (USB) and the Circulation Control Wing (CCW). Both concepts use the Coanda effect as a means of augmenting aerodynamic lift...USB), and a unique combination of the two (CCW/USB). Wing tip sails were used as a means of increasing th(, effective aspect ratio of these wings...wing tip sails are effective in reducing the induced drag of these powered- lift low aspect ratio wings under high-lift conditions. The induced drag

  16. Heat Build-Up and Blow-Out of Rubber Blocks

    DTIC Science & Technology

    1988-05-01

    heated without being subjected to mechanical working. (ii) Blow-out due only to heating Samples of an SBR compound (SBR2), a natural rubber compound...stiffness, extensibility, or resistance to tearing? Does repeated stressing play a direct role in causing the failure, as in mechanical fatigue of rubber...or is it merely a mechanism for raising the internal temperature to the level at which rapid decomposition takes place? In an attempt to answer some of

  17. Reduction of profile drag by blowing out through peg holes in areas of streamline separation bubbles

    NASA Technical Reports Server (NTRS)

    Horstmann, K. H.; Quast, A.

    1981-01-01

    Streamline separation bubbles on aircraft profiles and fuselages were investigated. The additional drag was examined in relation to increased angle of incidence and unusually high wall sheer stress. A reduction of the separation bubble and a decrease in drag is obtained with pneumatic turbulators that blow ram air out of 0.6mm pilot tubes at a distance of 16 mm. The pneumatic models are implemented at various positions and are found to be effective after the position of separation.

  18. Oxidation Processes in Blowing Steel With Inert Gas into the Ladle

    NASA Astrophysics Data System (ADS)

    Gizatulin, R. A.; Valuev, D. V.; Trifonov, V. A.; Valueva, A. V.; Serikbol, A.

    2015-09-01

    This work reports the possible development of oxidative processes in a metal when treating the melt in the ladle under intensive stirring with an inert gas. The industrial data have been received, confirming the possibility of reducing the concentration of silicon and aluminum in the metal, as well as changing the slag chemical composition with the bath blowing with the inert gas through the top submerged lance.

  19. Blow-up of the smooth solution to quantum hydrodynamic models in Rd

    NASA Astrophysics Data System (ADS)

    Guo, Boling; Wang, Guangwu

    2016-10-01

    In this paper we firstly investigate the local-in-time existence of smooth solution for the quantum hydrodynamic models (QHD) in Rd. Then we prove that any smooth solution of the QHD model which satisfies suitable conditions will blow up in finite time. The model can be derived from nonlinear Schrödinger equation by a Madelung transformation. The main idea is based on the construction of approximate solution and energy inequality.

  20. The exact asymptotic behavior of boundary blow-up solutions to infinity Laplacian equations

    NASA Astrophysics Data System (ADS)

    Wan, Haitao

    2016-08-01

    In this paper, we study the asymptotic behavior of viscosity solutions to boundary blow-up elliptic problem {Δ_{∞}u=b(x)f(u), xinΩ, u|_{partialΩ}=+∞,} where {Ω} is a bounded domain with C 2-boundary in {{R}N}, {bin C(bar{Ω})} is positive in {Ω}, which may be vanishing on the boundary, {fin C1([0, ∞))} is regularly varying or is rapidly varying at infinity.

  1. Blow-off momentum from melt and vapor in nuclear deflection scenarios

    NASA Astrophysics Data System (ADS)

    Howley, Kirsten; Managan, Robert; Wasem, Joseph

    2014-10-01

    For Earth-impacting objects that are large in size or have short warning times nuclear explosives are an effective threat mitigation response. Nuclear-based deflection works by means of conservation of momentum: as material is heated by incoming photons and neutrons it is ejected from the body which imparts momentum to the remaining mass of the asteroid. Predicting the complete response of a particular object is difficult, since the ejecta size and velocity distributions rely heavily on the unknown, complicated internal structure of the body. However, lower bounds on the blow-off momentum can be estimated using the melted and vaporized surface material. In this paper, we model the response of a one-dimensional SiO2 surface to monoenergetic soft X-ray, hard X-ray and neutron sources using Arbitrary Lagrangian-Eulerian radiation/hydrodynamic simulations. Errors in the blow-off momentum due to our hydrodynamic mesh resolution are quantified and inform zone sizing that balances numerical discretization error with computational efficiency. We explore deposited energy densities ranging from 1.1 to 200 times the melt energy density for SiO2, and develop an approximate relation that gives the mesh resolution needed for a desired percent error in the blow-off momentum as a function of deposited energy density and melt depth. Using these mesh constraints, the response of our one-dimensional SiO2 surface to the energy sources is simulated, and lower bounds are placed on the melt/vapor blow-off momentum as a function of deposited energy density and source energy type.

  2. Checklist and distribution maps of the blow flies of Venezuela (Diptera, Calliphoridae, Mesembrinellidae).

    PubMed

    Velásquez, Yelitza; Martínez-Sánchez, Ana Isabel; Thomas, Arianna; Rojo, Santos

    2017-01-01

    A checklist of the 39 species of blow flies (Calliphoridae and Mesembrinellidae) so far known to occur in Venezuela is provided, based on a thorough literature review and the examination of ca. 500 specimens deposited in the main entomological collections of the country. Data from the literature and museum collections were used to generate distribution maps for 37 species. Three species are recorded from Venezuela for the first time: Chrysomya putoria (Wiedemann, 1830), Mesembrinella spicata Aldrich, 1925 and Mesembrinella umbrosa Aldrich, 1922.

  3. Effect of jenny milk addition on the inhibition of late blowing in semihard cheese.

    PubMed

    Cosentino, C; Paolino, R; Valentini, V; Musto, M; Ricciardi, A; Adduci, F; D'Adamo, C; Pecora, G; Freschi, P

    2015-08-01

    The occurrence of late blowing defects in cheese produces negative effects on the quality and commercial value of the product. In this work, we verified whether the addition of raw jenny milk to bulk cow milk reduced the late blowing defects in semihard cheeses. During cheesemaking, different aliquots of jenny milk were poured into 2 groups of 4 vats, each containing a fixed amount of cow milk. A group of cheeses was created by deliberately contaminating the 4 vats with approximately 3 log10 cfu/mL milk of Clostridium tyrobutyricum CLST01. The other 4 vats, which were not contaminated, were used for a second group of cheeses. After 120 d of ripening, some physical, chemical, and microbiological parameters were evaluated on the obtained semihard cheeses. Differences in sensory properties among cheeses belonging to the uncontaminated group were evaluated by 80 regular consumers of cheese. Our results showed that the increasing addition of jenny milk to cow milk led to a reduction of pH and total bacterial count in both cheese groups, as well as C. tyrobutyricum spores that either grew naturally or artificially inoculated. We observed a progressive reduction of the occurrence of late blowing defects in cheese as consequence of the increasing addition of jenny milk during cheese making. Moreover, the addition of jenny milk did not affect the acceptability of the product, as consumers found no difference among cheeses concerning sensorial aspects. In conclusion, the important antimicrobial activity of lysozyme contained in jenny milk has been confirmed in the current research. It is recommend for use as a possible and viable alternative to egg lysozyme for controlling late blowing defects in cheese.

  4. Single, stretched membrane, structural module experiments

    SciTech Connect

    Wood, R.L.

    1986-02-01

    This report describes tests done on stretched-membrane heliostats used to reflect solar radiation onto a central receiver. The tests were used to validate prior analysis and mathematical models developed to describe module performance. The modules tested were three meters in diameter and had reflective polymer film laminated to the membrane. The frames were supported at three points equally spaced around the ring. Three modules were pneumatically attached with their weight suspended at the bottom support, two were pneumatically attached with their weight suspended from the upper mounts, and one was rigidly attached with its weight suspended at the bottom mount. By varying the membrane tension we could simulate a uniform wind loading normal to the mirror's surface. A video camera 15+ meters away from the mirror recorded the virtual image of a target grid as reflected by the mirrors' surface. The image was digitized and stored on a microcomputer. Using the law of reflection and analytic geometry, we computed the surface slopes of a sampling of points on the surface. The dominant module response was consistent with prior SERI analyses. The simple analytical model is quite adequate for designing and sizing single-membrane modules if the initial imperfections and their amplification are appropriately controlled. To avoid potential problems resulting from the fundamentally n = 2 deformation phenomena, we advise using either relatively stiffer ring frames or more than three support points.

  5. Stretched Lens Array Squarerigger (SLASR) Technology Maturation

    NASA Technical Reports Server (NTRS)

    O'Neill, Mark; McDanal, A.J.; Howell, Joe; Lollar, Louis; Carrington, Connie; Hoppe, David; Piszczor, Michael; Suszuki, Nantel; Eskenazi, Michael; Aiken, Dan; Fulton, Michael; Brandhorst, Henry; Schuller, Michael

    2007-01-01

    Since April 2005, our team has been underway on a competitively awarded program sponsored by NASA s Exploration Systems Mission Directorate to develop, refine, and mature the unique solar array technology known as Stretched Lens Array SquareRigger (SLASR). SLASR offers an unprecedented portfolio of performance metrics, SLASR offers an unprecedented portfolio of performance metrics, including the following: Areal Power Density = 300 W/m2 (2005) - 400 W/m2 (2008 Target) Specific Power = 300 W/kg (2005) - 500 W/kg (2008 Target) for a Full 100 kW Solar Array Stowed Power = 80 kW/cu m (2005) - 120 kW/m3 (2008 Target) for a Full 100 kW Solar Array Scalable Array Capacity = 100 s of W s to 100 s of kW s Super-Insulated Small Cell Circuit = High-Voltage (300-600 V) Operation at Low Mass Penalty Super-Shielded Small Cell Circuit = Excellent Radiation Hardness at Low Mass Penalty 85% Cell Area Savings = 75% Lower Array Cost per Watt than One-Sun Array Modular, Scalable, & Mass-Producible at MW s per Year Using Existing Processes and Capacities

  6. Global stability of gravitationally stretched capillary jets

    NASA Astrophysics Data System (ADS)

    Rubio-Rubio, Mariano; Sevilla, Alejandro; Gordillo, José Manuel

    2013-11-01

    We analyze the global linear stability of capillary jets stretched by gravity both experimentally and theoretically, extending the work by Sauter & Buggisch (J. Fluid Mech. vol. 533, 2005, pp. 237-257). Our results reveal the essential stabilizing role played by the axial curvature of the jet, the latter effect being especially relevant for injectors with a large diameter. The theoretical description, based on the one-dimensional mass and momentum equations retaining the exact expression for the interfacial curvature, accurately predicts the onset of jet self-excited oscillations experimentally observed for wide ranges of liquid viscosity and injector diameter. The marginal self-sustained oscillations observed in the experiments are shown to correspond to the excitation of the leading global mode of the jet. The model developed in the present work shows better agreement with the experimental jetting-dripping transition events than those available in the literature, thus allowing us to conclude that, surprisingly, the size of the steady threads produced at a given distance from the exit can be reduced by increasing the nozzle diameter. The proposed formulation allows to describe the inviscid limit, and experiments are being performed to study this distinguished case. Supported by Spanish MINECO under projects DPI 2011-28356-C03-01 and DPI 2011-28356-C03-02.

  7. The effect of blow flies (Diptera: Calliphoridae) on the size and weight of mangos (Mangifera indica L.)

    PubMed Central

    Naqqash, Muhammad Nadir; Saeed, Qamar; Ghouri, Fozia

    2016-01-01

    Background: Pollination has a great effect on the yield of fruit trees. Blow flies are considered as an effective pollinator compared to hand pollination in fruit orchards. Therefore, this study was designed to evaluate the effect of different pollination methods in mango orchards. Methodology: The impact of pollination on quantity and quality of mango yield by blow flies was estimated by using three treatments, i.e., open pollinated trees, trees were covered by a net in the presence of blow flies for pollination, and trees were covered with a net but without insects. Results: The maximum number of flowers was recorded in irregular types of inflorescence, i.e., 434.80 flowers/inflorescence. Fruit setting (bud) was higher in open pollinated mango trees (i.e. 37.00/inflorescence) than enclosed pollination by blow flies (i.e. 22.34/inflorescence). The size of the mango fruit was the highest (5.06 mm) in open pollinated tree than those pollinated by blow flies (3.93 mm) and followed by without any pollinator (3.18 mm) at marble stage. We found that the maximum weight of mango fruit (201.19 g) was in open pollinated trees. Discussion: The results demonstrated that blow flies can be used as effective mango pollinators along with other flies and bees. The blow flies have shown a positive impact on the quality and quantity of mango. This study will be helpful in future and also applicable at farm level to use blow flies as pollinators that are cheap and easy to rear. PMID:27441107

  8. Distributed Blowing and Suction for the Purpose of Streak Control in a Boundary Layer Subjected to a Favorable Pressure Gradient

    NASA Technical Reports Server (NTRS)

    Forgoston, Eric; Tumin, Anatoli; Ashpis, David E.

    2005-01-01

    An analysis of the optimal control by blowing and suction in order to generate stream- wise velocity streaks is presented. The problem is examined using an iterative process that employs the Parabolized Stability Equations for an incompressible uid along with its adjoint equations. In particular, distributions of blowing and suction are computed for both the normal and tangential velocity perturbations for various choices of parameters.

  9. Blow-up rates for higher-order semilinear parabolic equations and systems and some Fujita-type theorems

    NASA Astrophysics Data System (ADS)

    Pan, Hongjing; Xing, Ruixiang

    2008-03-01

    In this paper, we derive blow-up rates for higher-order semilinear parabolic equations and systems. Our proof is by contradiction and uses a scaling argument. This procedure reduces the problems of blow-up rate to Fujita-type theorems. In addition, we also give some new Fujita-type theorems for higher-order semilinear parabolic equations and systems with the time variable on . These results are not restricted to positive solutions.

  10. Experimental study on sulfur removal from ladle furnace refining slag in hot state by blowing air

    NASA Astrophysics Data System (ADS)

    Zhao, Li-hua; Lin, Lu; Wu, Qi-fan

    2016-01-01

    In view of the present problem of sulfur enrichment in the metallurgical recycling process of ladle furnace (LF) refining slag, a simple and efficient method of removing sulfur from this slag was proposed. The proposed method is compatible with current steelmaking processes. Sulfur removal from LF refining slag for SPHC steel (manufactured at a certain steel plant in China) by blowing air in the hot state was studied by using hot-state experiments in a laboratory. The FactSage software, a carbon/sulfur analyzer, and scanning electron microscopy in conjunction with energy-dispersive X-ray spectroscopy were used to test and analyze the sulfur removal effect and to investigate factors influencing sulfur removal rate. The results show that sulfur ions in LF refining slag can be oxidized into SO2 by O2 at high temperature by blowing air into molten slag; SO2 production was observed to reach a maximum with a small amount of blown O2 when the temperature exceeded 1350°C. At 1370°C and 1400°C, experimental LF refining slag is in the liquid state and exhibits good fluidity; under these conditions, the sulfur removal effect by blowing air is greater than 90wt% after 60 min. High temperature and large air flow rate are beneficial for removing sulfur from LF refining slag; compared with air flow rate, temperature has a greater strongly influences on the sulfur removal.

  11. Evaluation of HFC 245ca and HFC 236ea as foam blowing agents

    NASA Technical Reports Server (NTRS)

    Sharpe, Jon; Macarthur, Doug; Kollie, Tom; Graves, Ron; Liu, Matthew; Hendriks, Robert V.

    1995-01-01

    Hydrochlorofluorocarbon (HCFC) 141b has been selected as the interim blowing agent for use in urethane insulations on NASA's Space Shuttle External Tank. Due to the expected limited commercial lifetime of this material, research efforts at the NASA Thermal Protection Systems Materials Research Laboratory at the Marshall Space Flight Center are now being devoted to the identification and development of alternatives with zero ozone depletion potential. Physical blowing agents identified to date have included hydrocarbons, fluorocarbons, hydrofluoroethers, and more predominantly, hydrofluorocarbons (HFCs). The majority of the HFC evaluations in industry have focused on the more readily available, low boiling candidates such as HFC 134a. Higher boiling HFC candidates that could be handled at ambient conditions and use current processing equipment would be more desirable. This paper will describe results from a research program of two such candidate HFC's performed as a cooperative effort between Martin Marietta Manned Space Systems, the U.S. Environmental Protection Agency, and Oak Ridge National Laboratories. The purpose of this effort was to perform a cursory evaluation of the developmental HFC's 245ca and 236ea as blowing agents in urethane based insulations. These two materials were selected from screening tests of 37 C2, C3, and C4 isomers based on physical properties, atmospheric lifetime, flammability, estimated toxicity, difficulty of synthesis, suitability for dual use as a refrigerant, and other factors. Solubility of the two materials in typical foam components was tested, pour foaming trials were performed, and preliminary data were gathered regarding foam insulation performance.

  12. LES-based characterization of a suction and oscillatory blowing fluidic actuator

    NASA Astrophysics Data System (ADS)

    Kim, Jeonglae; Moin, Parviz

    2015-11-01

    Recently, a novel fluidic actuator using steady suction and oscillatory blowing was developed for control of turbulent flows. The suction and oscillatory blowing (SaOB) actuator combines steady suction and pulsed oscillatory blowing into a single device. The actuation is based upon a self-sustained mechanism of confined jets and does not require any moving parts. The control output is determined by a pressure source and the geometric details, and no additional input is needed. While its basic mechanisms have been investigated to some extent, detailed characteristics of internal turbulent flows are not well understood. In this study, internal flows of the SaOB actuator are simulated using large-eddy simulation (LES). Flow characteristics within the actuator are described in detail for a better understanding of the physical mechanisms and improving the actuator design. LES predicts the self-sustained oscillations of the turbulent jet. Switching frequency, maximum velocity at the actuator outlets, and wall pressure distribution are in good agreement with the experimental measurements. The computational results are used to develop simplified boundary conditions for numerical experiments of active flow control. Supported by the Boeing company.

  13. Interaction of Suction and Pulsed Blowing with a Laminar Boundary Layer

    NASA Astrophysics Data System (ADS)

    Seifert, Avraham; Marom, Liad

    2015-11-01

    The presentation will describe a fundamental study of active flow control (AFC) using the steady suction and oscillatory blowing actuator (SaOB), identifying its effects on a laminar boundary layer. Recent experiments showed this effective and efficient actuator as a drag reduction device .......[e.g., Wilson et al., AIAA J, 2013]. However, improved fundamental understanding of the boundary layer (BL) interaction with suction and oscillatory blowing and the combination of these two effects in close proximity is desired. The current experiment, performed in a laminar flow, will result in improved efficiency of the actuator and will enable development of a reliable predictive capability of this flow control method. The interaction with a laminar BL is crucial for the project due to the lack of interaction with the random turbulence, the thicker BL and lower skin-friction that enables greater effect of the controlled BL. Furthermore, fundamental interaction principles could be easier to identify and understand in laminar flows, where critical trends will not be masked by turbulence, and the averaging process will better represent the time dependent flow. The results demonstrate that while the oscillatory blowing is robust and has a strong effect on the flow evolution, the steady suction introduced upstream has a crucial role in the efficient operation of the AFC system.

  14. Blow-up problems for the heat equation with a local nonlinear Neumann boundary condition

    NASA Astrophysics Data System (ADS)

    Yang, Xin; Zhou, Zhengfang

    2016-09-01

    This paper estimates the blow-up time for the heat equation ut = Δu with a local nonlinear Neumann boundary condition: The normal derivative ∂ u / ∂ n =uq on Γ1, one piece of the boundary, while on the rest part of the boundary, ∂ u / ∂ n = 0. The motivation of the study is the partial damage to the insulation on the surface of space shuttles caused by high speed flying subjects. We show the finite time blow-up of the solution and estimate both upper and lower bounds of the blow-up time in terms of the area of Γ1. In many other work, they need the convexity of the domain Ω and only consider the problem with Γ1 = ∂ Ω. In this paper, we remove the convexity condition and only require ∂Ω to be C2. In addition, we deal with the local nonlinearity, namely Γ1 can be just part of ∂Ω.

  15. Beyond blow-up in excitatory integrate and fire neuronal networks: Refractory period and spontaneous activity.

    PubMed

    Cáceres, María J; Perthame, Benoît

    2014-06-07

    The Network Noisy Leaky Integrate and Fire equation is among the simplest model allowing for a self-consistent description of neural networks and gives a rule to determine the probability to find a neuron at the potential v. However, its mathematical structure is still poorly understood and, concerning its solutions, very few results are available. In the midst of them, a recent result shows blow-up in finite time for fully excitatory networks. The intuitive explanation is that each firing neuron induces a discharge of the others; thus increases the activity and consequently the discharge rate of the full network. In order to better understand the details of the phenomena and show that the equation is more complex and fruitful than expected, we analyze further the model. We extend the finite time blow-up result to the case when neurons, after firing, enter a refractory state for a given period of time. We also show that spontaneous activity may occur when, additionally, randomness is included on the firing potential VF in regimes where blow-up occurs for a fixed value of VF.

  16. Effects of environmental temperature on oviposition behavior in three blow fly species of forensic importance.

    PubMed

    Ody, Helen; Bulling, Mark T; Barnes, Kate M

    2017-03-14

    A number of factors are known to affect blow fly behavior with respect to oviposition. Current research indicates that temperature is the most significant factor. However temperature thresholds for oviposition in forensically important blow flies have not been well studied. Here, the oviposition behavior of three species of forensically important blow fly species (Calliphora vicina, Calliphora vomitoria and Lucilia sericata,) was studied under controlled laboratory conditions over a range of temperatures (10-40°C). Lower temperature thresholds for oviposition of 16°C and 17.5°C were established for C. vomitoria and L. sericata respectively, whilst C. vicina continued to lay eggs at 10°C. C. vomitoria and L. sericata both continued to lay eggs at 40°C, whilst the highest temperature at which oviposition occurred in C. vicina was 35°C. Within these thresholds there was considerable variation in the number of surviving pupae, with a general pattern of a single peak within the range of temperatures at which eggs were laid, but with the pattern being much less distinct for L. sericata.

  17. Investigating the potential of fluorescent fingerprint powders as a marker for blow fly larvae (Diptera: calliphoridae).

    PubMed

    Rosati, Jennifer Y; Robinson, Scott D; Devine, Richard

    2015-05-01

    Four fluorescent fingerprint powders (RedWop(™) , GreenWop(™) , Basic Yellow(™) , and Yellow Powder(™) ) were evaluated as a marker for blow fly larvae. Administration methods included ingestion (high vs. low concentration) or topical. Ingestion of high concentrations of Basic Yellow(™) and RedWop(™) caused higher larval mortality. Basic Yellow(™) delayed development and adult emergence while RedWop(™) and Yellow Powder(™) had a significant effect on particular stages of development, however, emergence time was not altered. Optimal administration is through ingestion at low concentration levels (<10%) or topically, with GreenWop(™) demonstrating minimal adverse effects. Optimum wavelength for discrimination between powders was 450 nm. This research can aid in investigative training to increase visibility of larval and pupal blow flies. It can also be used in entomological studies to differentiate between larval blow flies (or other dipteran) species or individuals to further understand complex interactions and behavior during larval development.

  18. Augmentation of Fighter-Aircraft Performance by Spanwise Blowing over the Wing Leading Edge

    NASA Technical Reports Server (NTRS)

    Seginer, A.; Salomon, M.

    1983-01-01

    Spanwise blowing over the wing and canard of a 1:35 model of a close-coupled-canard fighter airplane configuration (similar to the Kfir-C2) was investigated experimentally in low-speed flow. Tests were conducted at airspeeds of 30 m/sec (Reynolds number of 1.8 x 10 to the 5th power based on mean aerodynamic chord) with angle-of-attack sweeps from -8 to 60 deg, and yaw-angle sweeps from -8 to 36 deg at fixed angles of attack 0, 10, 20, 25, 30, and 35 deg. Significant improvement in lift-curve slope, maximum lift, drag polar and lateral/directional stability was found, enlarging the flight envelope beyond its previous low-speed/maximum-lift limit. In spite of the highly swept (60 deg) leading edge, the efficiency of the lift augmentation by blowing was relatively high and was found to increase with increasing blowing momentum on the close-coupled-canard configuration. Interesting possibilities of obtaining much higher efficiencies with swirling jets were indicated.

  19. Augmentation of fighter-aircraft performance by spanwise blowing over the wing leading edge

    NASA Technical Reports Server (NTRS)

    Seginer, A.; Salomon, M.

    1983-01-01

    Spanwise blowing over the wing and canard of a 1:35 model of a close-coupled-canard fighter-airplane configuration (similar to the Kfir-C2) was investigated experimentally in low-speed flow. Tests were conducted at airspeeds of 30 m/sec (Reynolds number of 1.8 x 10 to the 5th power based on mean aerodynamic chord) with angle-of-attack sweeps from -8 deg to 60 deg, and yaw-angle sweeps from -8 deg to 36 deg at fixed angles of attack 0 deg, 10 deg, 20 deg, 25 deg, 30 deg, and 35 deg. Significant improvement in lift-curve slope, maximum lift, drag polar and lateral/directional stability was found, enlarging the flight envelope beyond its previous low-speed/maximum-lift limit. In spite of the highly swept (60 deg) leading edge, the efficiency of the lift augmentation by blowing was relatively high and was found to increase with increasing blowing momentum on the close-coupled-canard configuration. Interesting possibilities of obtaining much higher efficiencies with swirling jets were indicated.

  20. A contoured gap coaxial plasma gun with injected plasma armature.

    PubMed

    Witherspoon, F Douglas; Case, Andrew; Messer, Sarah J; Bomgardner, Richard; Phillips, Michael W; Brockington, Samuel; Elton, Raymond

    2009-08-01

    A new coaxial plasma gun is described. The long term objective is to accelerate 100-200 microg of plasma with density above 10(17) cm(-3) to greater than 200 km/s with a Mach number above 10. Such high velocity dense plasma jets have a number of potential fusion applications, including plasma refueling, magnetized target fusion, injection of angular momentum into centrifugally confined mirrors, high energy density plasmas, and others. The approach uses symmetric injection of high density plasma into a coaxial electromagnetic accelerator having an annular gap geometry tailored to prevent formation of the blow-by instability. The injected plasma is generated by numerous (currently 32) radially oriented capillary discharges arranged uniformly around the circumference of the angled annular injection region of the accelerator. Magnetohydrodynamic modeling identified electrode profiles that can achieve the desired plasma jet parameters. The experimental hardware is described along with initial experimental results in which approximately 200 microg has been accelerated to 100 km/s in a half-scale prototype gun. Initial observations of 64 merging injector jets in a planar cylindrical testing array are presented. Density and velocity are presently limited by available peak current and injection sources. Steps to increase both the drive current and the injected plasma mass are described for next generation experiments.