Low Gravity Freefall Facilities

NASA Technical Reports Server (NTRS)

1981-01-01

Composite of Marshall Space Flight Center's Low-Gravity Free Fall Facilities.These facilities include a 100-meter drop tower and a 100-meter drop tube. The drop tower simulates in-flight microgravity conditions for up to 4.2 seconds for containerless processing experiments, immiscible fluids and materials research, pre-flight hardware design test and flight experiment simulation. The drop tube simulates in-flight microgravity conditions for up to 4.6 seconds and is used extensively for ground-based microgravity convection research in which extremely small samples are studied. The facility can provide deep undercooling for containerless processing experiments that require materials to remain in a liquid phase when cooled below the normal solidification temperature.

Microgravity

NASA Image and Video Library

1981-03-30

Composite of Marshall Space Flight Center's Low-Gravity Free Fall Facilities.These facilities include a 100-meter drop tower and a 100-meter drop tube. The drop tower simulates in-flight microgravity conditions for up to 4.2 seconds for containerless processing experiments, immiscible fluids and materials research, pre-flight hardware design test and flight experiment simulation. The drop tube simulates in-flight microgravity conditions for up to 4.6 seconds and is used extensively for ground-based microgravity convection research in which extremely small samples are studied. The facility can provide deep undercooling for containerless processing experiments that require materials to remain in a liquid phase when cooled below the normal solidification temperature.

Sandia Research and Development Board: Minutes of the 33rd Meeting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castle, M.

1950-02-08

Notes about the barometric fuzing system testing, drops of stockpile weapons requested by the Strategic Air Command, simultaneous drops and the interaction of the baro systems, changes of desired military characteristics of atomic weapons.

Environmental Assessment, Establishing a Drop Zone at the Energetic Materials Research and Testing Center in Socorro, New Mexico and Finding of No Significant Impact (FONSI)

DTIC Science & Technology

2007-11-07

action is open space, and free of any residential or other structures . Biological Resources Minor impacts to vegetation and wildlife may occur from...mountains, rills, gullies, or other notable geologic features. There are no residences or other structures within the proposed drop zone. 3.2 Airspace...research, testing and training related to energetic materials. The land has also been used for livestock grazing. There are no structures on the

Inverted drop testing and neck injury potential.

PubMed

Forrest, Stephen; Herbst, Brian; Meyer, Steve; Sances, Anthony; Kumaresan, Srirangam

2003-01-01

Inverted drop testing of vehicles is a methodology that has long been used by the automotive industry and researchers to test roof integrity and is currently being considered by the National Highway Traffic Safety Administration as a roof strength test. In 1990 a study was reported which involved 8 dolly rollover tests and 5 inverted drop tests. These studies were conducted with restrained Hybrid III instrumented Anthropometric Test Devices (ATD) in production and rollcaged vehicles to investigate the relationship between roof strength and occupant injury potential. The 5 inverted drop tests included in the study provided a methodology producing "repeatable roof impacts" exposing the ATDs to the similar impact environment as those seen in the dolly rollover tests. Authors have conducted two inverted drop test sets as part of an investigation of two real world rollover accidents. Hybrid-III ATD's were used in each test with instrumented head and necks. Both test sets confirm that reduction of roof intrusion and increased headroom can significantly enhance occupant protection. In both test pairs, the neck force of the dummy in the vehicle with less crush and more survival space was significantly lower. Reduced roof crush and dynamic preservation of the occupant survival space resulted in only minor occupant contact and minimal occupant loading, establishing a clear causal relationship between roof crush and neck injuries.

The Effects of High School Organization on Dropping Out: An Exploratory Investigation. CPRE Research Report Series.

ERIC Educational Resources Information Center

Bryk, Anthony S.; Thum, Yeow Meng

Examined in this paper are the effects of school characteristics on both the probability of dropping out and absenteeism as the strongest predictor of dropping out. The project employed a subsample from the High School and Beyond database that contains results from questionnaires and achievement tests given in 1980 to approximately 30,000…

Liquid drop stability for protein crystal growth in microgravity

NASA Technical Reports Server (NTRS)

Owen, Robert B.; Broom, Beth H.; Snyder, Robert S.; Daniel, Ron

1987-01-01

It is possible to grow protein crystals for biomedical research in microgravity by deploying a protein-rich solution from a syringe, forming a drop in which crystallization can occur with the proper degree of supersaturation. Drop stability is critical to the success of this research, due to the large drop sizes which can be achieved in space. In order to determine the type of syringe tips most suitable to support these large drops, tests were performed during brief periods of weightlessness onboard the NASA KC-135 low-gravity simulation aircraft. The drops were analyzed using three simple models in which the samples were approximated by modified pendulum and spring systems. It was concluded that the higher frequency systems were the most stable, indicating that of the syringes utilized, a disk-shaped configuration provided the most stable environment of low-gravity protein crystal growth.

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

NASA Technical Reports Server (NTRS)

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

1983-01-01

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

Development of Drop/Shock Test in Microelectronics and Impact Dynamic Analysis for Uniform Board Response

NASA Astrophysics Data System (ADS)

Kallolimath, Sharan Chandrashekar

For the past several years, many researchers are constantly developing and improving board level drop test procedures and specifications to quantify the solder joint reliability performance of consumer electronics products. Predictive finite element analysis (FEA) by utilizing simulation software has become widely acceptable verification method which can reduce time and cost of the real-time test process. However, due to testing and metrological limitations it is difficult not only to simulate exact drop condition and capture critical measurement data but also tedious to calibrate the system to improve test methods. Moreover, some of the important ever changing factors such as board flexural rigidity, damping, drop height, and drop orientation results in non-uniform stress/strain distribution throughout the test board. In addition, one of the most challenging tasks is to quantify uniform stress and strain distribution throughout the test board and identify critical failure factors. The major contributions of this work are in the four aspects of the drop test in electronics as following. First of all, an analytical FEA model was developed to study the board natural frequencies and responses of the system with the consideration of dynamic stiffness, damping behavior of the material and effect of impact loading condition. An approach to find the key parameters that affect stress and strain distributions under predominate mode responses was proposed and verified with theoretical solutions. Input-G method was adopted to study board response behavior and cut boundary interpolation methods was used to analyze local model solder joint stresses with the development of global/local FEA model in ANSYS software. Second, no ring phenomenon during the drop test was identified theoretically when the test board was modeled as both discrete system and continuous system. Numerical analysis was then conducted by FEA method for detailed geometry of attached chips with solder-joints. No ring test conditions was proposed and verified for the current widely used JEDEC standard. The significance of impact loading parameters such as pulse magnitude, pulse duration, pulse shapes and board dynamic parameter such as linear hysteretic damping and dynamic stiffness were discussed. Third, Kirchhoff's plate theory by principle of minimum potential energy was adopted to develop the FEA formulation to consider the effect of material hysteretic damping for the currently used JEDEC board test and proposed no-ring response test condition. Fourth, a hexagonal symmetrical board model was proposed to address the uniform stress and strain distribution throughout the test board and identify the critical failure factors. Dynamic stress and strain of the hexagonal board model were then compared with standard JEDEC board for both standard and proposed no-ring test conditions. In general, this line of research demonstrates that advanced techniques of FEA analysis can provide useful insights concerning the optimal design of drop test in microelectronics.

Heat transfer and pressure drop performance of a finned-tube heat exchanger proposed for use in the NASA Lewis Altitude Wind Tunnel

NASA Technical Reports Server (NTRS)

Vanfossen, G. J.

1985-01-01

A segment of the heat exchanger proposed for use in the NASA Lewis Altitude Wind Tunnel (AWT) facility has been tested under dry and icing conditions. The heat exchanger has the largest pressure drop of any component in the AWT loop. It is therefore critical that its performance be known at all conditions before the final design of the AWT is complete. The heat exchanger segment is tested in the NASA Lewis Icing Research Tunnel (IRT) in order to provide an icing cloud environment similar to what will be encountered in the AWT. Dry heat transfer and pressure drop data are obtained and compared to correlations available in the literature. The effects of icing sprays on heat transfer and pressure drop are also investigated.

On the effectiveness of incorporating shear thickening fluid with fumed silica particles in hip protectors

NASA Astrophysics Data System (ADS)

Haris, A.; Goh, B. W. Y.; Tay, T. E.; Lee, H. P.; Rammohan, A. V.; Tan, V. B. C.

2018-01-01

The objective of this research is to develop a smart hip protector by incorporating shear thickening fluid (STF) into conventional foam hip protectors. The shear thickening properties of fumed silica particles dispersed in liquid polyethylene glycol (PEG) were determined from rheological tests. Dynamic drop tests, using a 4 kg drop platen at 0.5 m drop height, were conducted to study how STF improves energy absorption as compared to unfilled foam and PEG filled foam. The results show that PEG filled foam reduces the mean peak force transmitted by a further 55% and mean peak displacement by 32.5% as compared to the unfilled foam; the STF filled foam further reduces mean peak force and displacement by 15% and 41% respectively when compared to the PEG filled foam. At a displacement of 22 mm, the STF filled foam absorbs 7.4 times more energy than the PEG filled foam. The results of varying the drop mass and drop height show that the energy absorbed per unit displacement for STF filled foam is always higher than that of PEG filled foam. Finally, the effectiveness of a prototype of hip protector made from 15 mm thick STF filled foam in preventing hip fractures was studied under two different loading conditions: distributed load (plate drop test) and concentrated load (ball drop test). The results of the plate and ball drop tests show that among all hip protectors tested in this study, only the prototype can reduce the mean peak impact force to be lower than the force required to fracture a hip bone (3.1 kN) regardless of the type of loading. Moreover, the peak force of the prototype is about half of this value, suggesting thinner prototype could have been used instead. These findings show that STF is effective in improving the performance of hip protectors.

B-52B-008/DTV (Drop Test Vehicle) configuration 1 (with and without fins) flight test results - captive flight and drop test missions

NASA Technical Reports Server (NTRS)

Quade, D. A.

1978-01-01

The B-52B-008 drop test consisted of one takeoff roll to 60 KCAS, two captive flights to accomplish limited safety of flight flutter and structural demonstration testing, and seven drop test flights. Of the seven drop test missions, one flight was aborted due to the failure of the hook mechanism to release the drop test vehicle (DTV); but the other six flights successfully dropped the DTV.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lillo, Thomas Martin

During the first quarter of FY17, research has focused on: 1. Generation of synthetic microstructures of welds 2. Aging of gamma prime 3. Short term creep tests 4. Preparation for stress drop tests to determine the threshold stress.

A modified Pegasus rocket drops away after release from NASA's B-52B before accelerating the X-43A over a Pacific Ocean test range on Nov. 16, 2004

NASA Image and Video Library

2004-11-16

The third X-43A hypersonic research aircraft and its modified Pegasus booster rocket drop away from NASA's B-52B launch aircraft over the Pacific Ocean on November 16, 2004. The mission originated from the NASA Dryden Flight Research Center at Edwards Air Force Base, California. Moments later the Pegasus booster ignited to accelerate the X-43A to its intended speed of Mach 10.

Analytical and experimental investigation of liquid double drop dynamics: Preliminary design for space shuttle experiments

NASA Technical Reports Server (NTRS)

1981-01-01

The preliminary grant assessed the use of laboratory experiments for simulating low g liquid drop experiments in the space shuttle environment. Investigations were begun of appropriate immiscible liquid systems, design of experimental apparatus and analyses. The current grant continued these topics, completed construction and preliminary testing of the experimental apparatus, and performed experiments on single and compound liquid drops. A continuing assessment of laboratory capabilities, and the interests of project personnel and available collaborators, led to, after consultations with NASA personnel, a research emphasis specializing on compound drops consisting of hollow plastic or elastic spheroids filled with liquids.

Opening Loads Analyses for Various Disk-Gap-Band Parachutes

NASA Technical Reports Server (NTRS)

Cruz, J. R.; Kandis, M.; Witkowski, A.

2003-01-01

Detailed opening loads data is presented for 18 tests of Disk-Gap-Band (DGB) parachutes of varying geometry with nominal diameters ranging from 43.2 to 50.1 ft. All of the test parachutes were deployed from a mortar. Six of these tests were conducted via drop testing with drop test vehicles weighing approximately 3,000 or 8,000 lb. Twelve tests were conducted in the National Full-Scale Aerodynamics Complex 80- by 120-foot wind tunnel at the NASA Ames Research Center. The purpose of these tests was to structurally qualify the parachute for the Mars Exploration Rover mission. A key requirement of all tests was that peak parachute load had to be reached at full inflation to more closely simulate the load profile encountered during operation at Mars. Peak loads measured during the tests were in the range from 12,889 to 30,027 lb. Of the two test methods, the wind tunnel tests yielded more accurate and repeatable data. Application of an apparent mass model to the opening loads data yielded insights into the nature of these loads. Although the apparent mass model could reconstruct specific tests with reasonable accuracy, the use of this model for predictive analyses was not accurate enough to set test conditions for either the drop or wind tunnel tests. A simpler empirical model was found to be suitable for predicting opening loads for the wind tunnel tests to a satisfactory level of accuracy. However, this simple empirical model is not applicable to the drop tests.

Finite Element Simulations of Two Vertical Drop Tests of F-28 Fuselage Sections

NASA Technical Reports Server (NTRS)

Jackson, Karen E.; Littell, Justin D.; Annett, Martin S.; Haskin, Ian M.

2018-01-01

In March 2017, a vertical drop test of a forward fuselage section of a Fokker F-28 MK4000 aircraft was conducted as part of a joint NASA/FAA project to investigate the performance of transport aircraft under realistic crash conditions. In June 2017, a vertical drop test was conducted of a wing-box fuselage section of the same aircraft. Both sections were configured with two rows of aircraft seats, in a triple-double configuration. A total of ten Anthropomorphic Test Devices (ATDs) were secured in seats using standard lap belt restraints. The forward fuselage section was also configured with luggage in the cargo hold. Both sections were outfitted with two hat racks, each with added ballast mass. The drop tests were performed at the Landing and Impact Research facility located at NASA Langley Research Center in Hampton, Virginia. The measured impact velocity for the forward fuselage section was 346.8-in/s onto soil. The wing-box section was dropped with a downward facing pitch angle onto a sloping soil surface in order to create an induced forward acceleration in the airframe. The vertical impact velocity of the wing-box section was 349.2-in/s. A second objective of this project was to assess the capabilities of finite element simulations to predict the test responses. Finite element models of both fuselage sections were developed for execution in LS-DYNA(Registered Trademark), a commercial explicit nonlinear transient dynamic code. The models contained accurate representations of the airframe structure, the hat racks and hat rack masses, the floor and seat tracks, the luggage in the cargo hold for the forward section, and the detailed under-floor structure in the wing-box section. Initially, concentrated masses were used to represent the inertial properties of the seats, restraints, and ATD occupants. However, later simulations were performed that included finite element representations of the seats, restraints, and ATD occupants. These models were developed to more accurately replicate the seat loading of the floor and to enable prediction of occupant impact responses. Models were executed to generate analytical predictions of airframe responses, which were compared with test data to validate the model. Comparisons of predicted and experimental structural deformation and failures were made. Finally, predicted and experimental soil deformation and crater depths were also compared for both drop test configurations.

NASA High-Speed 2D Photogrammetric Measurement System

NASA Technical Reports Server (NTRS)

Dismond, Harriett R.

2012-01-01

The object of this report is to provide users of the NASA high-speed 2D photogrammetric measurement system with procedures required to obtain drop-model trajectory and impact data for full-scale and sub-scale models. This guide focuses on use of the system for vertical drop testing at the NASA Langley Landing and Impact Research (LandIR) Facility.

49 CFR 178.810 - Drop test.

Code of Federal Regulations, 2013 CFR

2013-10-01

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

49 CFR 178.1045 - Drop test.

Code of Federal Regulations, 2013 CFR

2013-10-01

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

49 CFR 178.965 - Drop test.

Code of Federal Regulations, 2013 CFR

2013-10-01

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

49 CFR 178.603 - Drop test.

Code of Federal Regulations, 2013 CFR

2013-10-01

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

Study of imbalanced internal resistance on drop voltage of LiFePO4 battery system connected in parallel

NASA Astrophysics Data System (ADS)

Adie Perdana, Fengky; Supriyanto, Agus; Purwanto, Agus; Jamaluddin, Anif

2017-01-01

The purpose of this research focuses on the effect of imbalanced internal resistance for the drop voltage of LiFePO4 18650 battery system connected in parallel. The battery pack has been assembled consist of two cell battery LiFePO4 18650 that has difference combination of internal resistance. Battery pack was tested with 1/C constant current charging, 3,65V per group sel, 3,65V constant voltage charging, 5 minutes of rest time between charge and discharge process, 1/2C Constant current discharge until 2,2V, 26 cycle of measurement test, and 4320 minutes rest time after the last charge cycle. We can conclude that the difference combination of internal resistance on the battery pack seriously influence the drop voltage of a battery. Theoretical and experimental result show that the imbalance of internal resistance during cycling are mainly responsible for the drop voltage of LiFePO4 parallel batteries. It is thus a good way to avoid drop voltage fade of parallel battery system by suppressing variations of internal resistance.

B-52B/DTV (Drop Test Vehicle) flight test results: Drop test missions

NASA Technical Reports Server (NTRS)

Doty, L. J.

1985-01-01

The NASA test airplane, B-52B-008, was a carrier for drop tests of the shuttle booster recovery parachute system. The purpose of the test support by Boeing was to monitor the vertical loads on the pylon hooks. The hooks hold the Drop Test Vehicle to the B-52 pylon during drop test missions. The loads were monitored to assure the successful completion of the flight and the safety of the crew.

Study on Mechanical Properties of Barite Concrete under Impact Load

NASA Astrophysics Data System (ADS)

Chen, Z. F.; Cheng, K.; Wu, D.; Gan, Y. C.; Tao, Q. W.

2018-03-01

In order to research the mechanical properties of Barite concrete under impact load, a group of concrete compression tests was carried out under the impact load by using the drop test machine. A high-speed camera was used to record the failure process of the specimen during the impact process. The test results show that:with the increase of drop height, the loading rate, the peak load, the strain under peak load, the strain rate and the dynamic increase factor (DIF) all increase gradually. The ultimate tensile strain is close to each other, and the time of impact force decreases significantly, showing significant strain rate effect.

Test Package Plummets in the Zero Gravity Research Facility

NASA Image and Video Library

1966-09-21

National Aeronautics and Space Administration (NASA) Lewis Research Center. Lewis researchers had been studying the behavior of liquid in microgravity for several years using ballistic rocket flights, aircraft flying series of parabolas, and in the 2.2-Second Drop Tower. It was easier to control experiments and repeat tests based on almost instantaneous test results in the Zero Gravity Research Facility than missiles or aircraft. It also more than doubled the microgravity time of the original drop tower. The experiments were enclosed in a large experiment package that was suspended inside the chamber. A vacuum was introduced to the chamber before the package was released. The test equipment allowed researchers to film and take measurements of the experiment as it was falling. The 2500‐pound package was slowed by special Styrofoam‐like pellets in a decelerator cart. An experiment, traveling 176 feet per second, was stopped in about 15 feet of deceleration material. The facility’s designers struggled to determine the correct type of deceleration pellets to use. For several years Lewis engineers tested various samples from manufacturers. The final selection was not made until the facility’s completion in May 1966, just before the facility made its public debut at the 1966 Inspection of the Center.

Design of a Helmet Liner for Improved Low Velocity Impact Protection

DTIC Science & Technology

2013-05-01

FIGURE 14. MONORAIL DROP TEST WITH DOT-SIZE C HEADFORM AND HEMISPHERICAL ANVIL ........................... 14  FIGURE 15. ACH PAD CONFIGURATION. LEFT...materials. In this project, the monorail drop test device, used for the helmeted headform drop test, was modified for material testing as shown in Figure...a guided free fall drop test using a monorail drop test apparatus as shown in Figure 14. All helmets tested in this study were ACH-Size Large and

14 CFR 23.727 - Reserve energy absorption drop test.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Reserve energy absorption drop test. 23.727... Construction Landing Gear § 23.727 Reserve energy absorption drop test. (a) If compliance with the reserve energy absorption requirement in § 23.723(b) is shown by free drop tests, the drop height may not be less...

14 CFR 23.727 - Reserve energy absorption drop test.

Code of Federal Regulations, 2010 CFR

2010-01-01

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

14 CFR 23.727 - Reserve energy absorption drop test.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Reserve energy absorption drop test. 23.727... Construction Landing Gear § 23.727 Reserve energy absorption drop test. (a) If compliance with the reserve energy absorption requirement in § 23.723(b) is shown by free drop tests, the drop height may not be less...

14 CFR 23.727 - Reserve energy absorption drop test.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Reserve energy absorption drop test. 23.727... Construction Landing Gear § 23.727 Reserve energy absorption drop test. (a) If compliance with the reserve energy absorption requirement in § 23.723(b) is shown by free drop tests, the drop height may not be less...

14 CFR 23.727 - Reserve energy absorption drop test.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Reserve energy absorption drop test. 23.727... Construction Landing Gear § 23.727 Reserve energy absorption drop test. (a) If compliance with the reserve energy absorption requirement in § 23.723(b) is shown by free drop tests, the drop height may not be less...

Fuel Cycle Research and Development Accident Tolerant Fuels Series 1 (ATF-1) Irradiation Testing FY 2016 Status Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Core, Gregory Matthew

This report contains a summary of irradiation testing of Fuel Cycle Research and Development (FCRD) Accident Tolerant Fuels Series 1 (ATF 1) experiments performed at Idaho National Laboratory (INL) in FY 2016. ATF 1 irradiation testing work performed in FY 2016 included design, analysis, and fabrication of ATF-1B drop in capsule ATF 1 series experiments and irradiation testing of ATF-1 capsules in the ATR.

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

NASA Astrophysics Data System (ADS)

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

2014-05-01

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

Liquid and gelled sprays for mixing hypergolic propellants using an impinging jet injection system

NASA Astrophysics Data System (ADS)

James, Mark D.

The characteristics of sprays produced by liquid rocket injectors are important in understanding rocket engine ignition and performance. The includes, but is not limited to, drop size distribution, spray density, drop velocity, oscillations in the spray, uniformity of mixing between propellants, and the spatial distribution of drops. Hypergolic ignition and the associated ignition delay times are also important features in rocket engines, providing high reliability and simplicity of the ignition event. The ignition delay time is closely related to the level and speed of mixing between a hypergolic fuel and oxidizer, which makes the injection method and conditions crucial in determining the ignition performance. Although mixing and ignition of liquid hypergolic propellants has been studied for many years, the processes for injection, mixing, and ignition of gelled hypergolic propellants are less understood. Gelled propellants are currently under investigation for use in rocket injectors to combine the advantages of solid and liquid propellants, although not without their own difficulties. A review of hypergolic ignition has been conducted for selected propellants, and methods for achieving ignition have been established. This research is focused on ignition using the liquid drop-on-drop method, as well as the doublet impinging jet injector. The events leading up to ignition, known as pre-ignition stage are discussed. An understanding of desirable ignition and combustion performance requires a study of the effects of injection, temperature, and ambient pressure conditions. A review of unlike-doublet impinging jet injection mixing has also been conducted. This includes mixing factors in reactive and non-reactive sprays. Important mixing factors include jet momentum, jet diameter and length, impingement angle, mass distribution, and injector configuration. An impinging jet injection system is presented using an electro-mechanically driven piston for injecting liquid and gelled hypergolic propellants. A calibration of the system is done with water in preparation for hypergolic injection, and characteristics of individual water and gelled JP-8 jets are studied at velocities in the range of 3 ft/s to 61 ft/s. The piston response is also analyzed to characterize the startup and steady state liquid jet velocities using orifices of 0.02" in diameter. Using this injection system, water and gelled JP-8 sprays are formed and compared across injection velocities of 30 ft/s to 121 ft/s. The comparison includes sheet shape and disintegration, total number of drops, drop size distributions, drop eccentricity, most populated drop bin size, and mean drop sizes. A test matrix for investigating the effects of mixing on ignition of MMH and IRFNA through different injection conditions are presented. First, water and IRFNA are injected to create a spray in the combustion chamber in order to verify effectiveness of test procedures and the test hardware. Next, injection of the hypergolic propellants MMH and IRFNA are done in accordance to the test matrix, although ignition was not observed as expected. These injections are followed by simple drop-on-drop tests to investigate propellant quality and ignition delay. Drop tests are performed with propellants IRFNA/MMH, and again with H2O2/Block 0 as possible propellant replacements for the proposed test plan.

49 CFR 572.102 - Drop test.

Code of Federal Regulations, 2013 CFR

2013-10-01

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

49 CFR 572.102 - Drop test.

Code of Federal Regulations, 2011 CFR

2011-10-01

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

14 CFR 29.727 - Reserve energy absorption drop test.

Code of Federal Regulations, 2010 CFR

2010-01-01

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

14 CFR 27.727 - Reserve energy absorption drop test.

Code of Federal Regulations, 2013 CFR

2013-01-01

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

14 CFR 27.727 - Reserve energy absorption drop test.

Code of Federal Regulations, 2011 CFR

2011-01-01

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

14 CFR 27.727 - Reserve energy absorption drop test.

Code of Federal Regulations, 2014 CFR

2014-01-01

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

14 CFR 29.727 - Reserve energy absorption drop test.

Code of Federal Regulations, 2011 CFR

2011-01-01

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

14 CFR 27.727 - Reserve energy absorption drop test.

Code of Federal Regulations, 2010 CFR

2010-01-01

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

14 CFR 27.727 - Reserve energy absorption drop test.

Code of Federal Regulations, 2012 CFR

2012-01-01

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

14 CFR 29.727 - Reserve energy absorption drop test.

Code of Federal Regulations, 2013 CFR

2013-01-01

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

14 CFR 29.727 - Reserve energy absorption drop test.

Code of Federal Regulations, 2014 CFR

2014-01-01

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

14 CFR 29.727 - Reserve energy absorption drop test.

Code of Federal Regulations, 2012 CFR

2012-01-01

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

49 CFR 572.102 - Drop test.

Code of Federal Regulations, 2012 CFR

2012-10-01

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

CPAS Preflight Drop Test Analysis Process

NASA Technical Reports Server (NTRS)

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

2015-01-01

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

40 CFR 71.24 - Permit applications.

Code of Federal Regulations, 2013 CFR

2013-07-01

... end of the post-reduction year. (4) If a source test will be the supporting basis for establishing post-reduction emissions for one or more emissions units in the early reductions source, the test... to the appropriate State agency; to the EPA Emission Standards Division, Mail Drop 13, Research...

40 CFR 71.24 - Permit applications.

Code of Federal Regulations, 2014 CFR

2014-07-01

... end of the post-reduction year. (4) If a source test will be the supporting basis for establishing post-reduction emissions for one or more emissions units in the early reductions source, the test... to the appropriate State agency; to the EPA Emission Standards Division, Mail Drop 13, Research...

40 CFR 71.24 - Permit applications.

Code of Federal Regulations, 2010 CFR

2010-07-01

... end of the post-reduction year. (4) If a source test will be the supporting basis for establishing post-reduction emissions for one or more emissions units in the early reductions source, the test... to the appropriate State agency; to the EPA Emission Standards Division, Mail Drop 13, Research...

40 CFR 71.24 - Permit applications.

Code of Federal Regulations, 2011 CFR

2011-07-01

... end of the post-reduction year. (4) If a source test will be the supporting basis for establishing post-reduction emissions for one or more emissions units in the early reductions source, the test... to the appropriate State agency; to the EPA Emission Standards Division, Mail Drop 13, Research...

40 CFR 71.24 - Permit applications.

Code of Federal Regulations, 2012 CFR

2012-07-01

... end of the post-reduction year. (4) If a source test will be the supporting basis for establishing post-reduction emissions for one or more emissions units in the early reductions source, the test... to the appropriate State agency; to the EPA Emission Standards Division, Mail Drop 13, Research...

Noncontact measurement of high temperature using optical fiber sensors

NASA Technical Reports Server (NTRS)

Claus, R. O.

1990-01-01

The primary goal of this research program was the investigation and application of noncontact temperature measurement techniques using optical techniques and optical fiber methods. In particular, a pyrometer utilizing an infrared optical light pipe and a multiwavelength filtering approach was designed, revised, and tested. This work was motivated by the need to measure the temperatures of small metallic pellets (approximately 3 mm diameter) in free fall at the Microgravity Materials Processing Drop Tube at NASA Marshall Space Flight Center. In addition, research under this program investigated the adaptation of holography technology to optical fiber sensors, and also examined the use of rare-earth dopants in optical fibers for use in measuring temperature. The pyrometer development effort involved both theoretical analysis and experimental tests. For the analysis, a mathematical model based on radiative transfer principles was derived. Key parameter values representative of the drop tube system, such as particle size, tube diameter and length, and particle temperature, were used to determine an estimate of the radiant flux that will be incident on the face of an optical fiber or light pipe used to collect radiation from the incandescent falling particle. An extension of this work examined the advantage of inclining or tilting the collecting fiber to increase the time that the falling particle remains in the fiber field-of-view. Those results indicate that increases in total power collected of about 15 percent may be realized by tilting the fiber. In order to determine the suitability of alternative light pipes and optical fibers, and experimental set-up for measuring the transmittance and insertion loss of infrared fibers considered for use in the pyrometer was assembled. A zirconium fluoride optical fiber and several bundles of hollow core fiber of varying diameters were tested. A prototype two-color pyrometer was assembled and tested at Virginia Tech, and then tested on the Drop Tube at Marshall Space Flight Center. Radiation from 5 mm diameter niobium drops falling in the Drop Tube was successfully detected, and recorded for later analysis. Subsequent analysis indicated that the imaging of light output from the light pipe onto the detector active areas was not identical for both detectors.

High-throughput 3D spheroid culture and drug testing using a 384 hanging drop array.

PubMed

Tung, Yi-Chung; Hsiao, Amy Y; Allen, Steven G; Torisawa, Yu-suke; Ho, Mitchell; Takayama, Shuichi

2011-02-07

Culture of cells as three-dimensional (3D) aggregates can enhance in vitro tests for basic biological research as well as for therapeutics development. Such 3D culture models, however, are often more complicated, cumbersome, and expensive than two-dimensional (2D) cultures. This paper describes a 384-well format hanging drop culture plate that makes spheroid formation, culture, and subsequent drug testing on the obtained 3D cellular constructs as straightforward to perform and adapt to existing high-throughput screening (HTS) instruments as conventional 2D cultures. Using this platform, we show that drugs with different modes of action produce distinct responses in the physiological 3D cell spheroids compared to conventional 2D cell monolayers. Specifically, the anticancer drug 5-fluorouracil (5-FU) has higher anti-proliferative effects on 2D cultures whereas the hypoxia activated drug commonly referred to as tirapazamine (TPZ) are more effective against 3D cultures. The multiplexed 3D hanging drop culture and testing plate provides an efficient way to obtain biological insights that are often lost in 2D platforms.

Correction of Pressure Drop in Steam and Water System in Performance Test of Boiler

NASA Astrophysics Data System (ADS)

Liu, Jinglong; Zhao, Xianqiao; Hou, Fanjun; Wu, Xiaowu; Wang, Feng; Hu, Zhihong; Yang, Xinsen

2018-01-01

Steam and water pressure drop is one of the most important characteristics in the boiler performance test. As the measuring points are not in the guaranteed position and the test condition fluctuation exsits, the pressure drop test of steam and water system has the deviation of measuring point position and the deviation of test running parameter. In order to get accurate pressure drop of steam and water system, the corresponding correction should be carried out. This paper introduces the correction method of steam and water pressure drop in boiler performance test.

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

NASA Technical Reports Server (NTRS)

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

1979-01-01

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

A Study on the Mechanical Properties and Impact-Induced Initiation Characteristics of Brittle PTFE/Al/W Reactive Materials.

PubMed

Ge, Chao; Maimaitituersun, Wubuliaisan; Dong, Yongxiang; Tian, Chao

2017-04-26

Polytetrafluoroethylene/aluminum/tungsten (PTFE/Al/W) reactive materials of three different component mass ratios (73.5/26.5/0, 68.8/24.2/7 and 63.6/22.4/14) were studied in this research. Different from the PTFE/Al/W composites published elsewhere, the materials in our research were fabricated under a much lower sintering temperature and for a much shorter duration to achieve a brittle property, which aims to provide more sufficient energy release upon impact. Quasi-static compression tests, dynamic compression tests at room and elevated temperatures, and drop weight tests were conducted to evaluate the mechanical and impact-induced initiation characteristics of the materials. The materials before and after compression tests were observed by a scanning electron microscope to relate the mesoscale structural characteristics to their macro properties. All the three types of materials fail at very low strains during both quasi-static and dynamic compression. The stress-strain curves for quasi-static tests show obvious deviations while that for the dynamic tests consist of only linear-elastic and failure stages typically. The materials were also found to exhibit thermal softening at elevated temperatures and were strain-rate sensitive during dynamic tests, which were compared using dynamic increase factors (DIFs). Drop-weight test results show that the impact-initiation sensitivity increases with the increase of W content due to the brittle mechanical property. The high-speed video sequences and recovered sample residues of the drop-weight tests show that the reaction is initiated at two opposite positions near the edges of the samples, where the shear force concentrates the most intensively, indicating a shear-induced initiation mechanism.

A Study on the Mechanical Properties and Impact-Induced Initiation Characteristics of Brittle PTFE/Al/W Reactive Materials

PubMed Central

Ge, Chao; Maimaitituersun, Wubuliaisan; Dong, Yongxiang; Tian, Chao

2017-01-01

Polytetrafluoroethylene/aluminum/tungsten (PTFE/Al/W) reactive materials of three different component mass ratios (73.5/26.5/0, 68.8/24.2/7 and 63.6/22.4/14) were studied in this research. Different from the PTFE/Al/W composites published elsewhere, the materials in our research were fabricated under a much lower sintering temperature and for a much shorter duration to achieve a brittle property, which aims to provide more sufficient energy release upon impact. Quasi-static compression tests, dynamic compression tests at room and elevated temperatures, and drop weight tests were conducted to evaluate the mechanical and impact-induced initiation characteristics of the materials. The materials before and after compression tests were observed by a scanning electron microscope to relate the mesoscale structural characteristics to their macro properties. All the three types of materials fail at very low strains during both quasi-static and dynamic compression. The stress-strain curves for quasi-static tests show obvious deviations while that for the dynamic tests consist of only linear-elastic and failure stages typically. The materials were also found to exhibit thermal softening at elevated temperatures and were strain-rate sensitive during dynamic tests, which were compared using dynamic increase factors (DIFs). Drop-weight test results show that the impact-initiation sensitivity increases with the increase of W content due to the brittle mechanical property. The high-speed video sequences and recovered sample residues of the drop-weight tests show that the reaction is initiated at two opposite positions near the edges of the samples, where the shear force concentrates the most intensively, indicating a shear-induced initiation mechanism. PMID:28772812

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

NASA Technical Reports Server (NTRS)

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

1984-01-01

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

Photogrammetric Measurements of CEV Airbag Landing Attenuation Systems

NASA Technical Reports Server (NTRS)

Barrows, Danny A.; Burner, Alpheus W.; Berry, Felecia C.; Dismond, Harriett R.; Cate, Kenneth H.

2008-01-01

High-speed photogrammetric measurements are being used to assess the impact dynamics of the Orion Crew Exploration Vehicle (CEV) for ground landing contingency upon return to earth. Test articles representative of the Orion capsule are dropped at the NASA Langley Landing and Impact Research (LandIR) Facility onto a sand/clay mixture representative of a dry lakebed from elevations as high as 62 feet (18.9 meters). Two different types of test articles have been evaluated: (1) half-scale metal shell models utilized to establish baseline impact dynamics and soil characterization, and (2) geometric full-scale drop models with shock-absorbing airbags which are being evaluated for their ability to cushion the impact of the Orion CEV with the earth s surface. This paper describes the application of the photogrammetric measurement technique and provides drop model trajectory and impact data that indicate the performance of the photogrammetric measurement system.

Review of Research on the Education of Intellectually and Academically Gifted Students.

ERIC Educational Resources Information Center

Rogers, Karen B.

The paper examines research on the education of gifted students. Studies are cited and conclusions drawn for 10 topic areas: (1) identification (methods, recommended commercial tests, sex differences, emotional differences); (2) rationale for special provisions; (3) talent loss (dropping out and educational deprivation); (4) needed personnel…

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

NASA Technical Reports Server (NTRS)

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

1996-01-01

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

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

NASA Technical Reports Server (NTRS)

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

1995-01-01

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

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

NASA Technical Reports Server (NTRS)

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

1983-01-01

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

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

NASA Technical Reports Server (NTRS)

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

1986-01-01

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

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

NASA Technical Reports Server (NTRS)

Smiley, Robert F; Horne, Walter B

1957-01-01

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

Drop Testing Representative Multi-Canister Overpacks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snow, Spencer D.; Morton, Dana K.

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

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

NASA Technical Reports Server (NTRS)

Jackson, Karen E.; Fuchs, Yvonne T.

2008-01-01

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

Measurements in liquid fuel sprays

NASA Technical Reports Server (NTRS)

Chigier, N.; Mao, C. P.

1985-01-01

A ground test facility is being established at NASA Lewis Research Center to simulate the environmental and flight conditions needed to study adverse weather effects. One of the most important components is the water spray system which consists of many nozzles fitted on spray bars. Water is injected through air-assisted atomizers to generate uniform size drops to simulate icing in clouds. The primary objective is to provide experimental data on drop size distribution over a wide range of operating conditions. Correlation equations for mean drop size and initial injection parameters are being determined to assist in the design and modification of the Altitude Wind Tunnel. Special emphasis is being placed on the study of the aerodynamic structure of the air-assisted atomizer sprays. Detailed measurements of the variation of drop size distribution and velocity as a function of time and space are being made. Accurate initial and boundary conditions are being provided for computer model evaluation.

Comparative Analysis of THOR-NT ATD vs. Hybrid III ATD in Laboratory Vertical Shock Testing

DTIC Science & Technology

2013-09-01

were taken both pretest and post - test for each test event (figure 5). Figure 5. Rigid fixture placed on the drop table with ATD seated: Hybrid III...6 3. Experimental Procedure 6 3.1 Test Setup...frames per second and with a Vision Research Phantom V9.1 (Wayne, NJ) high-speed video camera, sampling 1000 frames per second. 3. Experimental

Dream Chaser ALT-2 Free Flight

NASA Image and Video Library

2017-11-07

A lift device was attached to Sierra Nevada Corp’s Dream Chaser for a helicopter to pick it up to drop for its successful approach and landing test at NASA’s Armstrong Flight Research Center in California on Nov. 11, 2017.

Centrifuge in Free Fall: Combustion at Partial Gravity

NASA Technical Reports Server (NTRS)

Ferkul, Paul

2017-01-01

A centrifuge apparatus is developed to study the effect of variable acceleration levels in a drop tower environment. It consists of a large rotating chamber, within which the experiment is conducted. NASA Glenn Research Center 5.18-second Zero-Gravity Facility drop tests were successfully conducted at rotation rates up to 1 RPS with no measurable effect on the overall Zero-Gravity drop bus. Arbitrary simulated gravity levels from zero to 1-g (at a radius of rotation 30 cm) were produced. A simple combustion experiment was used to exercise the capabilities of the centrifuge. A total of 23 drops burning a simulated candle with heptane and ethanol fuel were performed. The effect of gravity level (rotation rate) and Coriolis force on the flames was observed. Flames became longer, narrower, and brighter as gravity increased. The Coriolis force tended to tilt the flames to one side, as expected, especially as the rotation rate was increased. The Zero-Gravity Centrifuge can be a useful tool for other researchers interested in the effects of arbitrary partial gravity on experiments, especially as NASA embarks on future missions which may be conducted in non-Earth gravity.

Partially Nested Randomized Controlled Trials in Education Research: A Guide to Design and Analysis. NCER 2014-2000

ERIC Educational Resources Information Center

Lohr, Sharon; Schochet, Peter Z.; Sanders, Elizabeth

2014-01-01

Suppose an education researcher wants to test the impact of a high school drop-out prevention intervention in which at-risk students attend classes to receive intensive summer school instruction. The district will allow the researcher to randomly assign students to the treatment classes or to the control group. Half of the students (the treatment…

An Assessment of the SEA Multi-Element Sensor for Liquid Water Content Calibration of the NASA GRC Icing Research Tunnel

NASA Technical Reports Server (NTRS)

Steen, Laura E.; Ide, Robert F.; Van Zante, Judith F.

2015-01-01

The NASA Glenn Icing Research tunnel has been using an Icing Blade technique to measure cloud liquid water content (LWC) since 1980. The IRT conducted tests with SEA Multi-Element sensors from 2009 to 2011 to assess their performance in measuring LWC. These tests revealed that the Multi-Element sensors showed some significant advantages over the Icing Blade, particularly at higher water contents, higher impingement rates, and large drop sizes. Results of these and other tests are presented here.

Simulating the Impact Response of Full-Scale Composite Airframe Structures

NASA Technical Reports Server (NTRS)

Fasanella, Edwin L.; Jackson, Karen E.; Littell, Justin D.; Seal, Michael D.

2012-01-01

NASA Langley Research Center obtained a composite helicopter cabin structure in 2010 from the US Army's Survivable Affordable Repairable Airframe Program (SARAP) that was fabricated by Sikorsky Aircraft Corporation. The cabin had been subjected to a vertical drop test in 2008 to evaluate a tilting roof concept to limit the intrusion of overhead masses into the fuselage cabin. Damage to the cabin test article was limited primarily to the roof. Consequently, the roof area was removed and the remaining structure was cut into test specimens including a large subfloor section and a forward framed fuselage section. In 2011, NASA and Sikorsky entered into a cooperative research agreement to study the impact responses of composite airframe structures and to evaluate the capabilities of the explicit transient dynamic finite element code, LS-DYNA®, to simulate these responses including damage initiation and progressive failure. Most of the test articles were manufactured of graphite unidirectional tape composite with a thermoplastic resin system. However, the framed fuselage section was constructed primarily of a plain weave graphite fabric material with a thermoset resin system. Test data were collected from accelerometers and full-field photogrammetry. The focus of this paper will be to document impact testing and simulation results for the longitudinal impact of the subfloor section and the vertical drop test of the forward framed fuselage section.

Temporal properties of secondary drop breakup in the bag-stamen breakup regime

NASA Astrophysics Data System (ADS)

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

2013-05-01

The situation of liquid drop bag-stamen breakup in a continuous air jet flow is investigated by a high speed camera. Test liquids include water, ethanol, and various glycerol mixtures. First, the morphology of bag-stamen breakup is observed and analyzed. The bag-stamen breakup range is found to be in good agreement with the model obtained by Rayleigh-Taylor instability. Then the disk and stamen deformation properties, the fragment average size, and size distribution of ring and stamen are researched in detail, respectively.

Determination of crash test pulses and their application to aircraft seat analysis

NASA Technical Reports Server (NTRS)

Alfaro-Bou, E.; Williams, M. S.; Fasanella, E. L.

1981-01-01

Deceleration time histories (crash pulses) from a series of twelve light aircraft crash tests conducted at NASA Langley Research Center (LaRC) were analyzed to provide data for seat and airframe design for crashworthiness. Two vertical drop tests at 12.8 m/s (42 ft/s) and 36 G peak deceleration (simulating one of the vertical light aircraft crash pulses) were made using an energy absorbing light aircraft seat prototype. Vertical pelvis acceleration measured in a 50 percentile dummy in the energy absorbing seat were found to be 45% lower than those obtained from the same dummy in a typical light aircraft seat. A hybrid mathematical seat-occupant model was developed using the DYCAST nonlinear finite element computer code and was used to analyze a vertical drop test of the energy absorbing seat. Seat and occupant accelerations predicted by the DYCAST model compared quite favorably with experimental values.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mandell, John F.; Ashwill, Thomas D.; Wilson, Timothy J.

This report presents an analysis of trends in fatigue results from the Montana State University program on the fatigue of composite materials for wind turbine blades for the period 2005-2009. Test data can be found in the SNL/MSU/DOE Fatigue of Composite Materials Database which is updated annually. This is the fifth report in this series, which summarizes progress of the overall program since its inception in 1989. The primary thrust of this program has been research and testing of a broad range of structural laminate materials of interest to blade structures. The report is focused on current types of infusedmore » and prepreg blade materials, either processed in-house or by industry partners. Trends in static and fatigue performance are analyzed for a range of materials, geometries and loading conditions. Materials include: sixteen resins of three general types, five epoxy based paste adhesives, fifteen reinforcing fabrics including three fiber types, three prepregs, many laminate lay-ups and process variations. Significant differences in static and fatigue performance and delamination resistance are quantified for particular materials and process conditions. When blades do fail, the likely cause is fatigue in the structural detail areas or at major flaws. The program is focused strongly on these issues in addition to standard laminates. Structural detail tests allow evaluation of various blade materials options in the context of more realistic representations of blade structure than do the standard test methods. Types of structural details addressed in this report include ply drops used in thickness tapering, and adhesive joints, each tested over a range of fatigue loading conditions. Ply drop studies were in two areas: (1) a combined experimental and finite element study of basic ply drop delamination parameters for glass and carbon prepreg laminates, and (2) the development of a complex structured resin-infused coupon including ply drops, for comparison studies of various resins, fabrics and pry drop thicknesses. Adhesive joint tests using typical blade adhesives included both generic testing of materials parameters using a notched-lap-shear test geometry developed in this study, and also a series of simulated blade web joint geometries fabricated by an industry partner.« less

An experimental design for total container impact response modeling at extreme temperatures

NASA Technical Reports Server (NTRS)

Kobler, V. P.; Wyskida, R. M.; Johannes, J. D.

1979-01-01

An experimental design (a drop test) was developed to test the effects of confinement upon cushions. The drop test produced consistent corner void cushion data from which mathematical models were developed. A mathematical relationship between temperature and drop height was found.

Investigation of the quality of stored red blood cells after simulated air drop in the maritime environment.

PubMed

Meli, Athinoula; Hancock, Vicky; Doughty, Heidi; Smedley, Steve; Cardigan, Rebecca; Wiltshire, Michael

2018-02-01

Maritime medical capability may be compromised by blood resupply. Air-dropped red blood cells (RBCs) is a possible mitigation factor. This study set out to evaluate RBC storage variables after a simulated parachute air drop into the sea, as limited data exist. The air load construction for the air drop of blood was subject to static drop assessment to simulate a worst-case parachute drop scenario. One control and two test Golden Hour shipping containers were each packaged with 10 RBC units. The control box was not dropped; Test Boxes 1 and 2 were further reinforced with waterproof boxes and underwent a simulated air drop on Day 7 or Day 8 postdonation, respectively. One day after the drop and once a week thereafter until Day 43 of storage, RBCs from each box were sampled and tested for full blood counts, hemolysis, adenosine triphosphate, 2,3-diphosphoglycerate, pH, extracellular potassium, glucose, lactate, deformability, and RBC microvesicles. The packaging configuration completed the air drop with no water ingress or physical damage. All units met UK specifications for volume, hemoglobin, and hemolysis. There were no significant differences for any of the variables studied between RBCs in the control box compared to RBCs in Test Boxes 1 and 2 combined over storage. The test proved that the packaging solution and the impact of a maritime air drop as performed in this study, on Day 7 or Day 8 postdonation, did not affect the in vitro quality of RBCs in SAGM over storage for 35 days. © 2017 AABB.

49 CFR 178.603 - Drop test.

Code of Federal Regulations, 2011 CFR

2011-10-01

... aluminum boxes, Composite packagings which are in the shape of a box Five—(one for each drop) First drop... impact. Where more than one orientation is possible for a given drop test, the orientation most likely to... example a closure or, for some 7 cylindrical drums, the welded longitudinal seam of the drum body. Boxes...

Response of Metals and Metallic Structures to Dynamic Loading

DTIC Science & Technology

1978-05-01

materials for service by testing under high rates of loading. Impact tests such as the Charpy test, the drop-weight tear test, and the dynamic tear...have clearly shown this for precracked charpy specimens and for the drop-weight tear test. Hence, there is a strong need for additional dynamic...dynamic fracture resistance ( Charpy , dynamic-tear, drop-weight tear test, etc.), normally assures that fracture in dynamically loaded structures is

Evaluation of wheelchair drop seat crashworthiness.

PubMed

Bertocci, G; Ha, D; van Roosmalen, L; Karg, P; Deemer, E

2001-05-01

Wheelchair seating crash performance is critical to protecting wheelchair users who remain seated in their wheelchairs during transportation. Relying upon computer simulation and sled testing seat loads associated with a 20 g/48 kph (20 g/30 mph) frontal impact and 50th percentile male occupant were estimated to develop test criteria. Using a static test setup we evaluated the performance of various types of commercially available drop seats against the loading test criteria. Five different types of drop seats (two specimens each) constructed of various materials (i.e. plastics, plywood, metal) were evaluated. Two types of drop seats (three of the total 10 specimens) met the 16650 N (3750 lb) frontal impact test criteria. While additional validation of the test protocol is necessary, this study suggests that some drop seat designs may be incapable of withstanding crash level loads.

Second Thoughts at Women's Colleges.

ERIC Educational Resources Information Center

Gose, Ben

1995-01-01

Despite a rise in enrollments at women's colleges nationwide, there is concern that the applicant pool is weakening. Average college entrance test scores of freshmen have dropped considerably since 1968. Some see research comparing women's performance at single-sex and coeducational colleges as unreliable. (MSE)

49 CFR 572.102 - Drop test.

Code of Federal Regulations, 2014 CFR

2014-10-01

... surface when the midsagittal plane is vertical. (4) Drop the headform from the specified height by means... test. (a) When the headform is dropped from a height of 14.8 inches in accordance with paragraph (b) of...

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

NASA Technical Reports Server (NTRS)

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

1979-01-01

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

Drop test analysis of fuselage section of R80 commuter aircraft by using finite element method

NASA Astrophysics Data System (ADS)

Anggono, Agus Dwi; Ardianto, Adik Nofa Rochma Wahyu

2017-04-01

In commercial aerospace development, feasibility accidents design or crashworthiness is a major concern in aviation safety. Fuselage structure plays an important role in absorbing energy during an accident. The research aims are to determine drop test phenomenon on the fuselage, to investigate deformation occurred in the structure of the fuselage, and to know the influence of the airframe falls position to the stress strain which occurred in the structure of the fuselage. This research was conducted by varying the fall angle of the fuselage in a vertical position or 0° and 15°. Fuselage design was modeled by using SolidWorks. Then the model is imported to the Abaqus for drop test simulation. From the simulation results, it can be obtained the phenomenon of deformation on the structure of the fuselage when it comes in contact with the rigid ground. The high deformation occurs shows the structure capabilities in order to absorb the impact. It could be happened because the deformation is influenced by internal energy and strain energy. The various positions shows the structure capability in order to withstand impact loads during periods of 4-8 seconds and the maximum deformation was reached in 12 seconds. The experiment on the vertical position and the position falls of 15° angle was delivered the highest stress strain. The stress was 483 MPa in struts section, 400.78 MPa in skin section, 358.28 MPa in the floor and 483 MPa in the cargo frame section.

Standalone Mobile Application for Shipping Services Based on Geographic Information System and A-Star Algorithm

NASA Astrophysics Data System (ADS)

Gunawan, D.; Marzuki, I.; Candra, A.

2018-03-01

Geographic Information Systems (GIS) plays an essential role in shipping service related application. By utilizing GIS, the courier can find the route to deliver goods for its customer. This research proposes a standalone mobile application to provide the shortest route to the destinations by utilizing geographic information systems with A-Star algorithm. This application is intended to be used although the area has no Internet network available. The developed application can handle several drop off points then calculates the shortest route that passes through all the drop off points. According to the conducted testing, the number of drop off points that can be calculated is influenced by the specification of the smartphone. More destinations require more smartphone resources and time to process.

Internally damped, self-arresting vertical drop-weight apparatus

NASA Technical Reports Server (NTRS)

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

1994-01-01

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

Experimental and Computational Analysis of Unidirectional Flow Through Stirling Engine Heater Head

NASA Technical Reports Server (NTRS)

Wilson, Scott D.; Dyson, Rodger W.; Tew, Roy C.; Demko, Rikako

2006-01-01

A high efficiency Stirling Radioisotope Generator (SRG) is being developed for possible use in long-duration space science missions. NASA s advanced technology goals for next generation Stirling convertors include increasing the Carnot efficiency and percent of Carnot efficiency. To help achieve these goals, a multi-dimensional Computational Fluid Dynamics (CFD) code is being developed to numerically model unsteady fluid flow and heat transfer phenomena of the oscillating working gas inside Stirling convertors. In the absence of transient pressure drop data for the zero mean oscillating multi-dimensional flows present in the Technology Demonstration Convertors on test at NASA Glenn Research Center, unidirectional flow pressure drop test data is used to compare against 2D and 3D computational solutions. This study focuses on tracking pressure drop and mass flow rate data for unidirectional flow though a Stirling heater head using a commercial CFD code (CFD-ACE). The commercial CFD code uses a porous-media model which is dependent on permeability and the inertial coefficient present in the linear and nonlinear terms of the Darcy-Forchheimer equation. Permeability and inertial coefficient were calculated from unidirectional flow test data. CFD simulations of the unidirectional flow test were validated using the porous-media model input parameters which increased simulation accuracy by 14 percent on average.

Modification Plans For The NASA 5.2 Second Drop Tower

NASA Technical Reports Server (NTRS)

Urban, David

2015-01-01

A design study is currently underway to examine the possibility of converting the NASA Glenn Research Center 5.2 second drop-tower to include testing at partial gravity levels and to increase the test duration to approximately 10 seconds and the number of tests conducted in a day to over 30. This will be achieved by converting to a magnetic-levitation system to drive the test capsule. This conversion will require concessions in certain areas to enable the enhanced capability. In particular the quality of g or vibration attainable in the new design is currently unknown. This capability may trade against payload mass, volume, or test duration. The acceleration quality for partial-g studies and the launch and deceleration levels are also in the process of definition. The status of the redesign study is presented along with discussion of the critical design options. Input from the community is sought to enable optimization of the design for future combustion applications.

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

NASA Technical Reports Server (NTRS)

Shreves, Christopher M.

2011-01-01

The Landing Parachute Demonstrator (LPD) was conceived as a low-cost, rapidly-developed means of providing soft landing for the Max Launch Abort System (MLAS) crew module (CM). Its experimental main parachute cluster deployment technique and off-the-shelf hardware necessitated a full-scale drop test prior to the MLAS mission in order to reduce overall mission risk. This test was successfully conducted at Wallops Flight Facility on March 6, 2009, with all vehicle and parachute systems functioning as planned. The results of the drop test successfully qualified the LPD system for the MLAS flight test. This document captures the design, concept of operations and results of the drop test.

The Development of Floats and Equipment for Research in Promoting It

NASA Technical Reports Server (NTRS)

Pabst, Wilhelm

1934-01-01

Providing information that will make possible a favorable compromise between landing impact and planing resistance is the immediate problem in experimental float development. A description of equipment to perform dropping tests are included as well as how to determine the landing impact.

49 CFR 173.175 - Permeation devices.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., flat and horizontal surface from a height of 1.8 m (5.9 feet): (i) One drop flat on the bottom; (ii) One drop flat on the top; (iii) One drop flat on the long side; (iv) One drop flat on the short side... stacked to a height of 3 m (10 feet) (including the test sample). (3) Each of the above tests may be...

Droplet Vaporization In A Levitating Acoustic Field

NASA Technical Reports Server (NTRS)

Ruff, G. A.; Liu, S.; Ciobanescu, I.

2003-01-01

Combustion experiments using arrays of droplets seek to provide a link between single droplet combustion phenomena and the behavior of complex spray combustion systems. Both single droplet and droplet array studies have been conducted in microgravity to better isolate the droplet interaction phenomena and eliminate or reduce the effects of buoyancy-induced convection. In most experiments involving droplet arrays, the droplets are supported on fibers to keep them stationary and close together before the combustion event. The presence of the fiber, however, disturbs the combustion process by introducing a source of heat transfer and asymmetry into the configuration. As the number of drops in a droplet array increases, supporting the drops on fibers becomes less practical because of the cumulative effect of the fibers on the combustion process. To eliminate the effect of the fiber, several researchers have conducted microgravity experiments using unsupported droplets. Jackson and Avedisian investigated single, unsupported drops while Nomura et al. studied droplet clouds formed by a condensation technique. The overall objective of this research is to extend the study of unsupported drops by investigating the combustion of well-characterized drop clusters in a microgravity environment. Direct experimental observations and measurements of the combustion of droplet clusters would provide unique experimental data for the verification and improvement of spray combustion models. In this work, the formation of drop clusters is precisely controlled using an acoustic levitation system so that dilute, as well as dense clusters can be created and stabilized before combustion in microgravity is begun. While the low-gravity test facility is being completed, tests have been conducted in 1-g to characterize the effect of the acoustic field on the vaporization of single and multiple droplets. This is important because in the combustion experiment, the droplets will be formed and levitated prior to ignition. Therefore, the droplets will begin to vaporize in the acoustic field thus forming the "initial conditions" for the combustion process. Understanding droplet vaporization in the acoustic field of this levitator is a necessary step that will help to interpret the experimental results obtained in low-gravity.

Lateral stability analysis for X-29A drop model using system identification methodology

NASA Technical Reports Server (NTRS)

Raney, David L.; Batterson, James G.

1989-01-01

A 22-percent dynamically scaled replica of the X-29A forward-swept-wing airplane has been flown in radio-controlled drop tests at the NASA Langley Research Center. A system identification study of the recorded data was undertaken to examine the stability and control derivatives that influence the lateral behavior of this vehicle with particular emphasis on an observed wing rock phenomenon. All major lateral stability derivatives and the damping-in-roll derivative were identified for angles of attack from 5 to 80 degrees by using a data-partitioning methodology and a modified stepwise regression algorithm.

49 CFR 178.965 - Drop test.

Code of Federal Regulations, 2012 CFR

2012-10-01

.... Water/anti-freeze solutions with a minimum specific gravity of 0.95 for testing at −18 °C (0 °F) or... of 0.45 cubic meters (15.9 cubic feet) or less must be subject to an additional drop test. (e) Drop... having essentially the same physical characteristics. (3) The specific gravity and viscosity of a...

49 CFR 178.965 - Drop test.

Code of Federal Regulations, 2014 CFR

2014-10-01

.... Water/anti-freeze solutions with a minimum specific gravity of 0.95 for testing at −18 °C (0 °F) or... of 0.45 cubic meters (15.9 cubic feet) or less must be subject to an additional drop test. (e) Drop... having essentially the same physical characteristics. (3) The specific gravity and viscosity of a...

49 CFR 178.965 - Drop test.

Code of Federal Regulations, 2011 CFR

2011-10-01

.... Water/anti-freeze solutions with a minimum specific gravity of 0.95 for testing at −18 °C (0 °F) or... of 0.45 cubic meters (15.9 cubic feet) or less must be subject to an additional drop test. (e) Drop... having essentially the same physical characteristics. (3) The specific gravity and viscosity of a...

Investigation of Dispersed and Dispersed Annular (rivulet or Thin Film) Flow Phase Separation in Tees.

NASA Astrophysics Data System (ADS)

McCreery, Glenn Ernest

An experimental and analytical investigation of dispersed and dispersed-annular (rivulet or thin film) flow phase separation in tees has been successfully completed. The research was directed at, but is not specific to, determining flow conditions, following a loss of coolant accident, in the large rectangular passageways leading to vacuum buildings in the containment envelope of some CANDU nuclear reactors. The primary objectives of the research were to: (1) obtain experimental data to help formulate and test mechanistic analytical models of phase separation, and (2) develop the analytical models in computer programs which predict phase separation from upstream flow and pressure conditions and downstream and side branch pressure boundary conditions. To meet these objectives an air-water experimental apparatus was constructed, and consists of large air blowers attached to a long rectangular duct leading to a tee in the horizontal plane. A variety of phenomena was investigated including, for comparison with computer predictions, air streamlines and eddy boundary geometry, drop size spectra, macroscopic mass balances, liquid rivulet pathlines, and trajectories of drops of known size and velocity. Four separate computer programs were developed to analyze phase separation. Three of the programs are used sequentially to calculate dispersed mist phase separation in a tee. The fourth is used to calculate rivulet or thin film pathlines. Macroscopic mass balances are calculated from a summation of mass balances for drops with representative sizes (and masses) spaced across the drop size spectrum. The programs are tested against experimental data, and accurately predict gas flow fields, drop trajectories, rivulet pathlines and macroscopic mass balances. In addition to development of the computer programs, analysis was performed to specify the scaling of dispersed mist and rivulet or thin film flow, to investigate pressure losses in tees, and the inter-relationship of loss coefficients, contraction coefficients, and eddy geometry. The important transient effects of liquid storage in eddies were also analyzed.

Antioxidant and inflammatory cytokine in tears of patients with dry eye syndrome treated with preservative-free versus preserved eye drops.

PubMed

Jee, Donghyun; Park, Sang Hee; Kim, Man Soo; Kim, Eun Chul

2014-07-03

To compare the antioxidant and inflammatory cytokine activities in tears of patients with dry eye syndrome treated with preservative-free versus preserved eye drops. A total of 100 patients with moderate to severe dry eye syndrome were randomly divided into two groups. Fifty patients (group 1) were treated four times with preservative-free 0.1% sodium hyaluronate and 0.1% fluorometholone eye drops in the first month and with preservative-free 0.1% sodium hyaluronate and 0.05% cyclosporine eye drops in the second and third months. Another 50 patients (group 2) were treated with preserved eye drops on the same schedule. Ocular Surface Disease Index, corneal fluorescein staining, Schirmer I test, tear film breakup time, impression cytology, and antioxidant and inflammatory cytokine activities in tears were evaluated. Treatment with preservative-free eye drops led to significant improvements in symptoms, tear film breakup time, Schirmer I score, and impression cytologic findings compared to treatment with preserved eye drops (P < 0.05) in patients with dry eye syndrome. There was a statistically significant decrease in the IL-1β, IL-6, IL-12, and TNF-α concentrations and a statistically significant increase in the catalase, peroxiredoxin 2, superoxide dismutase 2 (SOD 2), and thioredoxin mean fluorescence intensity (MFI) of tears in the preservative-free group at 1, 2, and 3 months compared to initial values, respectively (P < 0.05). Treatment with preservative-free eye drops is effective against the dry eye syndrome. Preservative-free eye drops seem to be more effective than preserved eye drops in decreasing ocular inflammation and in increasing antioxidant contents in tears of patients with dry eye syndrome. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

The Dried Bloodspot: Newborn Screening Research Saving the Lives of Babies

ERIC Educational Resources Information Center

Levy-Fisch, Jill; Gartzke, Micki; Leight, Kelly

2010-01-01

Newborn screening is a test done on every child born in the US shortly after birth to detect diseases where, if not diagnosed and treated in the newborn period, the child will suffer significant trauma, disability or die. A few drops of blood from each baby's heel is put on a card and sent to the state's public health lab for testing. Most states…

Response of an Impact Test Apparatus for Fall Protective Headgear Testing Using a Hybrid-III Head/Neck Assembly

PubMed Central

Caccese, V.; Ferguson, J.; Lloyd, J.; Edgecomb, M.; Seidi, M.; Hajiaghamemar, M.

2017-01-01

A test method based upon a Hybrid-III head and neck assembly that includes measurement of both linear and angular acceleration is investigated for potential use in impact testing of protective headgear. The test apparatus is based upon a twin wire drop test system modified with the head/neck assembly and associated flyarm components. This study represents a preliminary assessment of the test apparatus for use in the development of protective headgear designed to prevent injury due to falls. By including angular acceleration in the test protocol it becomes possible to assess and intentionally reduce this component of acceleration. Comparisons of standard and reduced durometer necks, various anvils, front, rear, and side drop orientations, and response data on performance of the apparatus are provided. Injury measures summarized for an unprotected drop include maximum linear and angular acceleration, head injury criteria (HIC), rotational injury criteria (RIC), and power rotational head injury criteria (PRHIC). Coefficient of variation for multiple drops ranged from 0.4 to 6.7% for linear acceleration. Angular acceleration recorded in a side drop orientation resulted in highest coefficient of variation of 16.3%. The drop test apparatus results in a reasonably repeatable test method that has potential to be used in studies of headgear designed to reduce head impact injury. PMID:28216804

Small Business Innovation Research (SBIR) Program, FY 1993. Program Solicitation 93.2, Closing Date: 2 August 1993

DTIC Science & Technology

1993-01-01

demonstrate improved Pd and Pfa with advanced algorithms, prepare final drop test demonstration. Potential Commercial Market: LADAR profiling and sensing...Field Refrigeration (CRFR) CATEGORY: Exploratory Development OBJECTIVE: To develop a nonpowered (nonelectric) closed-cycle solid-gas sorption

The influence of flow modification on air and PCM temperatures in an accumulative heat exchanger

NASA Astrophysics Data System (ADS)

Borcuch, Marcin; Musiał, Michał; Sztekler, Karol; Kalawa, Wojciech; Gumuła, Stanisław; Stefański, Sebastian

2018-06-01

The paper presents the influence of flow modification on the operation of an accumulative heat exchanger. This device can be used as a regenerator in ventilation and air supply systems. A heat exchanger uses ceresine (a mixture of paraffins) as a phase change material (PCM). The aim of this research was to determine the effect of flow modification on temperature distribution and pressure drops in the device. The introduction contains a short description of the test stand used, including the accumulative heat exchanger, the guide vanes, and the locations of measurement and control equipment. We found that additional objects limited vortex structures, increased the inside temperature, and dropped the pressure along the heat exchanger. Guidelines for further research are proposed and briefly discussed.

Combustion of Unconfined Droplet Clusters in Microgravity

NASA Technical Reports Server (NTRS)

Ruff, G. A.; Liu, S.

2001-01-01

Combustion experiments using arrays of droplets seek to provide a link between single droplet combustion phenomena and the behavior of complex spray combustion systems. Both single droplet and droplet array studies have been conducted in microgravity to better isolate the droplet interaction phenomena and eliminate or reduce the confounding effects of buoyancy-induced convection. In most experiments involving droplet arrays, the droplets are supported on fibers to keep them stationary and close together before the combustion event. The presence of the fiber, however, disturbs the combustion process by introducing a source of heat transfer and asymmetry into the configuration. As the number of drops in a droplet array increases, supporting the drops on fibers becomes less practical because of the cumulative effect of the fibers on the combustion process. To eliminate the effect of the fiber, several researchers have conducted microgravity experiments using unsupported droplets. Jackson and Avedisian investigated single, unsupported drops while Nomura et al. studied droplet clouds formed by a condensation technique. The overall objective of this research is to extend the study of unsupported drops by investigating the combustion of well-characterized drop clusters in a microgravity environment. Direct experimental observations and measurements of the combustion of droplet clusters would fill a large gap in our current understanding of droplet and spray combustion and provide unique experimental data for the verification and improvement of spray combustion models. In this work, the formation of drop clusters is precisely controlled using an acoustic levitation system so that dilute, as well as dense clusters can be created and stabilized before combustion in microgravity is begun. This paper describes the design and performance of the 1-g experimental apparatus, some preliminary 1-g results, and plans for testing in microgravity.

Pegasus Rocket Booster Being Prepared for X-43A/Hyper-X Flight Test

NASA Image and Video Library

1999-08-25

A close-up view of the front end of a Pegasus rocket booster being prepared by technicians at the Dryden Flight Research Center for flight tests with the X-43A "Hypersonic Experimental Vehicle," or "Hyper-X." The X-43A, which will be attached to the Pegasus booster and drop launched from NASA's B-52 mothership, was developed to research dual-mode ramjet/scramjet propulsion system at speeds from Mach 7 up to Mach 10 (7 to 10 times the speed of sound, which varies with temperature and altitude).

Development of the West Virginia University Small Microgravity Research Facility (WVU SMiRF)

NASA Astrophysics Data System (ADS)

Phillips, Kyle G.

West Virginia University (WVU) has created the Small Microgravity Research Facility (SMiRF) drop tower through a WVU Research Corporation Program to Stimulate Competitive Research (PSCoR) grant on its campus to increase direct access to inexpensive and repeatable reduced gravity research. In short, a drop tower is a tall structure from which experimental payloads are dropped, in a controlled environment, and experience reduced gravity or microgravity (i.e. "weightlessness") during free fall. Currently, there are several methods for conducting scientific research in microgravity including drop towers, parabolic flights, sounding rockets, suborbital flights, NanoSats, CubeSats, full-sized satellites, manned orbital flight, and the International Space Station (ISS). However, none of the aforementioned techniques is more inexpensive or has the capability of frequent experimentation repeatability as drop tower research. These advantages are conducive to a wide variety of experiments that can be inexpensively validated, and potentially accredited, through repeated, reliable research that permits frequent experiment modification and re-testing. Development of the WVU SMiRF, or any drop tower, must take a systems engineering approach that may include the detailed design of several main components, namely: the payload release system, the payload deceleration system, the payload lifting and transfer system, the drop tower structure, and the instrumentation and controls system, as well as a standardized drop tower payload frame for use by those researchers who cannot afford to spend money on a data acquisition system or frame. In addition to detailed technical development, a budgetary model by which development took place is also presented throughout, summarized, and detailed in an appendix. After design and construction of the WVU SMiRF was complete, initial calibration provided performance characteristics at various payload weights, and full-scale checkout via experimentation provided repeatability characteristics of the facility. Based on checkout instrumentation, Initial repeatability results indicated a drop time of 1.26 seconds at an average of 0.06g, with a standard deviation of 0.085g over the period of the drop, and a peak impact load of 28.72g, with a standard deviation of 10.73g, for a payload weight of 113.8 lbs. In order to thoroughly check out the facility, a full-scale, fully operational experiment was developed to create an experience that provides a comprehensive perspective of the end-user experience to the developer, so as to incorporate the details that may have been overlooked to the designer and/or developer, in this case, Kyle Phillips. The experiment that was chosen was to determine the effects of die swell, or extrudate swell, in reduced gravity. Die swell is a viscoelastic phenomenon that occurs when a dilatant, or shear-thickening substance is forced through a sufficient constriction, or "die," such that the substance expands, or "swells," downstream of the constriction, even while forming and maintaining a free jet at ambient sea level conditions. A wide range of dilatants exhibit die swell when subjected to the correct conditions, ranging from simple substances such as ketchup, oobleck, and shampoo to complex specially-formulated substances to be used for next generation body armor and high performance braking systems. To date, very few, if any, have researched the stabilizing effect that gravity may have on the phenomenon of die swell. By studying a fluid phenomenon in a reduced gravity environment, both the effect of gravity can be studied and the predominant forces acting on the fluid can be concluded. Furthermore, a hypothesis describing the behavior of a viscoelastic fluid particle employing the viscous Navier-Stokes Equations was derived to attempt to push the fluid mechanics community toward further integrating more fluid behavior into a unified mathematical model of fluid mechanics. While inconclusive in this experiment, several suggestions for future research were made in order to further the science behind die swell, and a comprehensive checkout of the facility and its operations were characterized. As a result of this checkout experience, several details were modified or added to the facility in order for the drop tower to be properly operated and provide the optimal user experience, such that open operation of the WVU SMiRF may begin in the Fall of 2014.

NACA/NASA test pilot Stanley P. Butchart

NASA Technical Reports Server (NTRS)

1954-01-01

Stanley P. Butchart joined the National Advisory Committee for Aeronautics' High-Speed Flight Research Station on May 10, 1951. Stan was the fourth research pilot hired at the Station affording him the opportunity to fly the early research aircraft. Stan began a flying career while attending Junior College. He received primary and secondary civilian pilot training, enlisting in the U.S. Navy in July 1942. Stan took his Navy air training at Corpus Christi, Texas. Upon completion of training he was assigned to a torpedo-bomber Air Group, VT-51, flying Grumman-General Motors TBM Avenger, a torpedo-bomber, from the carrier San Jacinto in the South Pacific. When World War II ended, Stan was released from active duty as a Navy Lieutenant, with a Distinguished Flying Cross and a Presidential Unit Citation among his service medals. Butchart elected to stay in the Naval Reserve group and flew for an additional 5 years while he attended the University of Washington. By 1950, Stan had earned bachelor degrees in aeronautical engineering and mechanical engineering. After graduation he went to work for Boeing Aircraft as a junior design engineer and was assigned to the B-47 body group. In May 1951, he arrived at the NACA facility to start a career as a research pilot. Stan flew the Douglas D-558-I #3 (12 flights, first on October 19, 1951), the Douglas D-558-II #3 (2 pilot check-out flights, first on June 26, 1953), Northrop X-4 (4 flights, first on May 27, 1952), Bell X-5 (13 flights, first in early December 1952). Other aircraft flown on research projects were the Boeing KC-135 Stratotanker, Convair CV-990, Boeing B-52-003, Boeing B-747, North American F-100A, Convair F-102, Piper PA-30 Twin Comanche, General Dynamics F-111, Boeing B-720, Convair CV-880, and the Boeing B-47 Stratojet, his favorite. he also flew many other aircraft. Stan did nearly all of the big airplane work at the Center. The biggest work load was flying the Boeing B-29 Stratofortress (Navy designation: P2B). At this time the pilot of the aircraft was the one in charge. It was the pilot who called for the chase planes before drop time, then for the fire trucks to be in position, and he counted down for the launch of the experimental aircraft after making sure everything and everyone was `ready.' The P2B was used in the launching of the D-558s while the B-29 carried the X-1s to altitude for drops. Stan was pilot of the P2B for 1 drop of the D-558-II #1 (1951 - 1954), 63 drops of the D-558-II #2 (1951 - 1956), and 38 drops of the D-558-II #3 (1951 - 1956). As pilot of the B-29 Stan flew for 1 drop of the Bell X-1A (1955), 13 drops of the Bell X-1B (1956-1958) and 22 drops of the X-1E (1955 - 1958). During the lifting body tow tests Stan was pilot of the R4D that towed the M2-F1 to altitude for release. He made 14 tows in 1966. On June 13, 1966, Stanley P. Butchart became the Chief Pilot at the National Aeronautics and Space Administrations' Flight Research Center and a few weeks later was named Acting Director of Flight Operations. There were 6 pilots assigned to the flight office at this time. On December 10, 1966, Stan became Chief of Flight Operations a position he held until his retirement on February 27, 1976. Stan authored several reports and presented research papers. He is a charter member of the Society of Experimental Test Pilots that had a membership of 65 in 1955, when chartered. Stan was elected to be a Fellow and had the honor of being the President in 1980. Butchart was presented the NACA Exceptional Service Medal for his decisions and actions in the X-1A explosion while attached to the B-29 aircraft on August 8, 1955.

The structure of evaporating and combusting sprays: Measurements and predictions

NASA Technical Reports Server (NTRS)

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

1984-01-01

An apparatus developed, to allow observations of monodisperse sprays, consists of a methane-fueled turbulent jet diffusion flame with monodisperse methanol drops injected at the burner exit. Mean and fluctuating-phase velocities, drop sizes, drop-mass fluxes and mean-gas temperatures were measured. Initial drop diameters of 100 and 180 microns are being considered in order to vary drop penetration in the flow and effects of turbulent dispersion. Baseline tests of the burner flame with no drops present were also conducted. Calibration tests, needed to establish methods for predicting drop transport, involve drops supported in the post-flame region of a flat-flame burner operated at various mixture ratios. Spray models which are being evaluated include: (1) locally homogeneous flow (LFH) analysis, (2) deterministic separated flow (DSF) analysis and (3) stochastic separated flow (SSF) analysis.

Are the Stress Drops of Small Earthquakes Good Predictors of the Stress Drops of Larger Earthquakes?

NASA Astrophysics Data System (ADS)

Hardebeck, J.

2017-12-01

Uncertainty in PSHA could be reduced through better estimates of stress drop for possible future large earthquakes. Studies of small earthquakes find spatial variability in stress drop; if large earthquakes have similar spatial patterns, their stress drops may be better predicted using the stress drops of small local events. This regionalization implies the variance with respect to the local mean stress drop may be smaller than the variance with respect to the global mean. I test this idea using the Shearer et al. (2006) stress drop catalog for M1.5-3.1 events in southern California. I apply quality control (Hauksson, 2015) and remove near-field aftershocks (Wooddell & Abrahamson, 2014). The standard deviation of the distribution of the log10 stress drop is reduced from 0.45 (factor of 3) to 0.31 (factor of 2) by normalizing each event's stress drop by the local mean. I explore whether a similar variance reduction is possible when using the Shearer catalog to predict stress drops of larger southern California events. For catalogs of moderate-sized events (e.g. Kanamori, 1993; Mayeda & Walter, 1996; Boyd, 2017), normalizing by the Shearer catalog's local mean stress drop does not reduce the standard deviation compared to the unmodified stress drops. I compile stress drops of larger events from the literature, and identify 15 M5.5-7.5 earthquakes with at least three estimates. Because of the wide range of stress drop estimates for each event, and the different techniques and assumptions, it is difficult to assign a single stress drop value to each event. Instead, I compare the distributions of stress drop estimates for pairs of events, and test whether the means of the distributions are statistically significantly different. The events divide into 3 categories: low, medium, and high stress drop, with significant differences in mean stress drop between events in the low and the high stress drop categories. I test whether the spatial patterns of the Shearer catalog stress drops can predict the categories of the 15 events. I find that they cannot, rather the large event stress drops are uncorrelated with the local mean stress drop from the Shearer catalog. These results imply that the regionalization of stress drops of small events does not extend to the larger events, at least with current standard techniques of stress drop estimation.

Drop "impact" on an airfoil surface.

PubMed

Wu, Zhenlong

2018-06-01

Drop impact on an airfoil surface takes place in drop-laden two-phase flow conditions such as rain and icing, which are encountered by wind turbines or airplanes. This phenomenon is characterized by complex nonlinear interactions that manifest rich flow physics and pose unique modeling challenges. In this article, the state of the art of the research about drop impact on airfoil surface in the natural drop-laden two-phase flow environment is presented. The potential flow physics, hazards, characteristic parameters, droplet trajectory calculation, drop impact dynamics and effects are discussed. The most key points in establishing the governing equations for a drop-laden flow lie in the modeling of raindrop splash and water film. The various factors affecting the drop impact dynamics and the effects of drop impact on airfoil aerodynamic performance are summarized. Finally, the principle challenges and future research directions in the field as well as some promising measures to deal with the adverse effects of drop-laden flows on airfoil performance are proposed. Copyright © 2018 Elsevier B.V. All rights reserved.

The Influence of Local Politics on Educational Decisions

ERIC Educational Resources Information Center

Bigham, Gary; Ray, Jan

2012-01-01

This ex post facto, causal-comparative research study examined student reading performance data within a school district before and after a school district-wide decision to alter the reading curriculum in response to local political pressure from parents. Data analysis revealed that test scores dropped to a significantly lower level, especially…

Collection Efficiencies of Various Airborne Spray Flux Samplers Used in Aerial Application Research

DTIC Science & Technology

2008-01-01

provided by ASTM Standard E1260: Standard Test Method for Determining Liquid Drop Size Characteristics in a Spray Using Optical Nonimaging Light...Size Characteristics in a Spray Using Optical Nonimaging Light-Scattering Instruments,” Annual Book of ASTM Stan- dards, ASTM International, West

Drop-Weight Impact Test on U-Shape Concrete Specimens with Statistical and Regression Analyses

PubMed Central

Zhu, Xue-Chao; Zhu, Han; Li, Hao-Ran

2015-01-01

According to the principle and method of drop-weight impact test, the impact resistance of concrete was measured using self-designed U-shape specimens and a newly designed drop-weight impact test apparatus. A series of drop-weight impact tests were carried out with four different masses of drop hammers (0.875, 0.8, 0.675 and 0.5 kg). The test results show that the impact resistance results fail to follow a normal distribution. As expected, U-shaped specimens can predetermine the location of the cracks very well. It is also easy to record the cracks propagation during the test. The maximum of coefficient of variation in this study is 31.2%; it is lower than the values obtained from the American Concrete Institute (ACI) impact tests in the literature. By regression analysis, the linear relationship between the first-crack and ultimate failure impact resistance is good. It can suggested that a minimum number of specimens is required to reliably measure the properties of the material based on the observed levels of variation. PMID:28793540

Deployment and Drop Test of Inflatable Aeroshell for Atmospheric Entry Capsule with using Large Scientific Balloon

NASA Astrophysics Data System (ADS)

Yamada, Kazuhiko; Suzuki, Kojiro; Honma, Naohiko; Abe, Daisuke; Makino, Hitoshi; Nagata, Yasunori; Kimura, Yusuke; Koyama, Masashi; Akita, Daisuke; Hayashi, Koichi; Abe, Takashi

A deployable and flexible aeroshell for atmospheric entry vehicles has attracted attention as an innovative space transportation system in the near future, because the large-area, low-mass aeroshell dramatically reduces aerodynamic heating and achieves a soft landing without a conventional parachute system thanks to its low ballistic coefficient. Various concepts of flexible aeroshell have been proposed in the past. Our group are researching and developing a flare-type membrane aeroshell sustained by inflatable torus. As a part of the development, a deployment and drop test of a capsule-type experimental vehicle with a 1.264-m-diameter flare-type membrane aeroshell sustained by inflatable torus was carried out using a large scientific balloon in August, 2009. The objectives of this experiment are 1) to demonstrate the remote inflation system of inflatable aeroshell, 2) to acquire aerodynamic performance of a low ballistic coefficient vehicle including an inflatable structure in subsonic region, and 3) to observe behavior and deformation of the flexible aeroshell during free flight. In this test, the inflatable aeroshell was deployed at an altitude 24.6km by radio command from ground station. After deployment, the experimental vehicle was dropped from the balloon and underwent free flight. The flight data and images of the aeroshell collected using onboard sensors were transmitted successfully during the flight by the telemetry system. The data showed that the vehicle was almost stable in free flight condition and the inflatable aeroshell was collapsed at expected altitude. This deployment and drop test was very successful and useful data for design of actual atmospheric-entry vehicles with inflatable structure was acquired as planned.

Student Design Challenges in Capillary Flow

NASA Technical Reports Server (NTRS)

Stocker, Dennis P.; Wollman, Andrew; Hall, Nancy R.; Weislogel, Mark; DeLombard, Richard

2016-01-01

For some grade 8-12 students, capillary flow has bridged the gap between the classroom and research facility, from normal gravity to microgravity. In the past four years, NASA and the Portland State University (PSU) have jointly challenged students to design test cells, using Computer-Aided Design (CAD), to study capillary action in microgravity as PSU has done on the International Space Station (ISS). Using the student-submitted CAD drawings, the test cells were manufactured by PSU and tested in their 2.1-second drop tower. The microgravity results were made available online for student analysis and reporting. Over 100 such experiments have been conducted, where there has been participation from 15 states plus a German school for the children of U.S. military personnel. In 2016, a related NASA challenge was held in partnership with the ASGSR, again, based on the research conducted by PSU. In this challenge, grade 9-12 students designed and built devices using capillary action to launch droplets as far as possible in NASAs 2.2 Second Drop Tower. Example results will be presented by students at this conference. The challenges engage students in ISS science and technology and can inspire them to pursue technical careers.

Influence of Electrification of Droplet on Hydrophobicity Reduction of Polymer Material during a Dynamic Drop Test

NASA Astrophysics Data System (ADS)

Haji, Kenichi; Shiibara, Daiki; Arata, Yoshihiro; Sakoda, Tatsuya; Otsubo, Masahisa

The dynamic drop test was proposed as a method to evaluate hydrophobicity reduction of polymer materials. In this test, the formation change of a water channel was confirmed, and thereafter, the remained droplets and the dropped droplets on the sampled surface were repulsed each other. The distributions of electrification on the droplet and the sample surface were measured. The influence of the electrified droplet on the hydrophobicity reduction was examined. The results showed that the polarity on the sample surface changed by the dropped droplet, leading to the hydrophobicity loss.

Generation of Homogenous Three-Dimensional Pancreatic Cancer Cell Spheroids Using an Improved Hanging Drop Technique

PubMed Central

Ware, Matthew J.; Colbert, Kevin; Keshishian, Vazrik; Ho, Jason; Corr, Stuart J.; Curley, Steven A.

2016-01-01

In vitro characterization of tumor cell biology or of potential anticancer drugs is usually performed using tumor cell lines cultured as a monolayer. However, it has been previously shown that three-dimensional (3D) organization of the tumor cells is important to provide insights on tumor biology and transport of therapeutics. Several methods to create 3D tumors in vitro have been proposed, with hanging drop technique being the most simple and, thus, most frequently used. However, in many cell lines this method has failed to form the desired 3D tumor structures. The aim of this study was to design and test an easy-to-use and highly reproducible modification of the hanging drop method for tumor sphere formation by adding methylcellulose polymer. Most pancreatic cancer cells do not form cohesive and manageable spheres when the original hanging drop method is used, thus we investigated these cell lines for our modified hanging drop method. The spheroids produced by this improved technique were analyzed by histology, light microscopy, immunohistochemistry, and scanning electron microscopy. Results show that using the proposed simple method; we were able to produce uniform spheroids for all five of the tested human pancreatic cancer cell lines; Panc-1, BxPC-3, Capan-1, MiaPaCa-2, and AsPC-1. We believe that this method can be used as a reliable and reproducible technique to make 3D cancer spheroids for use in tumor biology research and evaluation of therapeutic responses, and for the development of bio-artificial tissues. PMID:26830354

Generation of Homogenous Three-Dimensional Pancreatic Cancer Cell Spheroids Using an Improved Hanging Drop Technique.

PubMed

Ware, Matthew J; Colbert, Kevin; Keshishian, Vazrik; Ho, Jason; Corr, Stuart J; Curley, Steven A; Godin, Biana

2016-04-01

In vitro characterization of tumor cell biology or of potential anticancer drugs is usually performed using tumor cell lines cultured as a monolayer. However, it has been previously shown that three-dimensional (3D) organization of the tumor cells is important to provide insights on tumor biology and transport of therapeutics. Several methods to create 3D tumors in vitro have been proposed, with hanging drop technique being the most simple and, thus, most frequently used. However, in many cell lines this method has failed to form the desired 3D tumor structures. The aim of this study was to design and test an easy-to-use and highly reproducible modification of the hanging drop method for tumor sphere formation by adding methylcellulose polymer. Most pancreatic cancer cells do not form cohesive and manageable spheres when the original hanging drop method is used, thus we investigated these cell lines for our modified hanging drop method. The spheroids produced by this improved technique were analyzed by histology, light microscopy, immunohistochemistry, and scanning electron microscopy. Results show that using the proposed simple method; we were able to produce uniform spheroids for all five of the tested human pancreatic cancer cell lines; Panc-1, BxPC-3, Capan-1, MiaPaCa-2, and AsPC-1. We believe that this method can be used as a reliable and reproducible technique to make 3D cancer spheroids for use in tumor biology research and evaluation of therapeutic responses, and for the development of bio-artificial tissues.

The structure of dilute combusting sprays

NASA Technical Reports Server (NTRS)

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

1985-01-01

An experimental and theoretical study of drop processes in a turbulent flame is described. The experiments involved a monodisperse (105 and 180 micro m initial diameter) stream of methanol drops injected at the base of a turbulent methane-fueled diffusion flame burning in still air. The following measurements were made: mean and fluctuating phase velocities, mean drop number flux, drop-size distributions and mean gas-phase temperatures. Measurements were compared with predictions of two separated flow models: (1) deterministic separated flow, where drop-turbulence interactions are ignored; and (2) stochastic separated flow, where drop-turbulence interactions are considered using random-walk computations. The stochastic separated flow analysis yielded best agreement with measurements, since it provides for turbulent dispersion of drops which was important for present test conditions (and probably for most combusting sprays as well). Distinguishing the presence or absence of envelope flames around the drops, however, was relatively unimportant for present test conditions, since the drops spent most of their lifetime in fuel-rich regions of the flow where this distinction is irrelevant.

Combat Helmet-Headform Coupling Characterized from Blunt Impact Events

DTIC Science & Technology

2011-11-01

Testing was completed on a monorail drop tower to analyze the effect of helmet/headform coupling on the blunt impact behavior of ACH helmets using FMVSS...designates its own methods and test equipment: a drop tower ( monorail or twin- wire), headform (DOT, ISO, NOCSAE), headform CG accelerometer (single or...the more anthropomorphic International Standard Organization (ISO) half headform. Testing was completed on a monorail drop tower to analyze the effect

Performance evaluation of Space Shuttle SRB parachutes from air drop and scaled model wind tunnel tests. [Solid Rocket Booster recovery system

NASA Technical Reports Server (NTRS)

Moog, R. D.; Bacchus, D. L.; Utreja, L. R.

1979-01-01

The aerodynamic performance characteristics have been determined for the Space Shuttle Solid Rocket Booster drogue, main, and pilot parachutes. The performance evaluation on the 20-degree conical ribbon parachutes is based primarily on air drop tests of full scale prototype parachutes. In addition, parametric wind tunnel tests were performed and used in parachute configuration development and preliminary performance assessments. The wind tunnel test data are compared to the drop test results and both sets of data are used to determine the predicted performance of the Solid Rocket Booster flight parachutes. Data from other drop tests of large ribbon parachutes are also compared with the Solid Rocket Booster parachute performance characteristics. Parameters assessed include full open terminal drag coefficients, reefed drag area, opening characteristics, clustering effects, and forebody interference.

Quantitative study of sniffer leak rate and pressure drop leak rate of liquid nitrogen panels of SST-1 tokamak

NASA Astrophysics Data System (ADS)

Pathan, F. S.; Khan, Z.; Semwal, P.; Raval, D. C.; Joshi, K. S.; Thankey, P. L.; Dhanani, K. R.

2008-05-01

Steady State Super-conducting (SST-1) Tokamak is in commissioning stage at Institute for Plasma Research. Vacuum chamber of SST-1 Tokamak consists of 1) Vacuum vessel, an ultra high vacuum (UHV) chamber, 2) Cryostat, a high vacuum (HV) chamber. Cryostat encloses the liquid helium cooled super-conducting magnets (TF and PF), which require the thermal radiation protection against room temperature. Liquid nitrogen (LN2) cooled panels are used to provide thermal shield around super-conducting magnets. During operation, LN2 panels will be under pressurized condition and its surrounding (cryostat) will be at high vacuum. Hence, LN2 panels must have very low leak rate. This paper describes an experiment to study the behaviour of the leaks in LN2 panels during sniffer test and pressure drop test using helium gas.

14 CFR 27.725 - Limit drop test.

Code of Federal Regulations, 2014 CFR

2014-01-01

... introduced into the drop test by appropriate energy absorbing devices or by the use of an effective mass. (c... critical from the standpoint of the energy to be absorbed by it. (d) When an effective mass is used in...=specified free drop height (inches). L=ration of assumed rotor lift to the rotorcraft weight. d=deflection...

14 CFR 27.725 - Limit drop test.

Code of Federal Regulations, 2013 CFR

2013-01-01

... introduced into the drop test by appropriate energy absorbing devices or by the use of an effective mass. (c... critical from the standpoint of the energy to be absorbed by it. (d) When an effective mass is used in...=specified free drop height (inches). L=ration of assumed rotor lift to the rotorcraft weight. d=deflection...

14 CFR 27.725 - Limit drop test.

Code of Federal Regulations, 2012 CFR

2012-01-01

... introduced into the drop test by appropriate energy absorbing devices or by the use of an effective mass. (c... critical from the standpoint of the energy to be absorbed by it. (d) When an effective mass is used in...=specified free drop height (inches). L=ration of assumed rotor lift to the rotorcraft weight. d=deflection...

Research on Upgrading Structures for Host and Risk Area Shelters

DTIC Science & Technology

1982-09-01

both "as-built" and upgraded configurations. These analysis and prediction techniques have been applied to floors and roofs constructed of many...scale program and were previously applied to full-scale wood floor tests (Ref. 2). TEST ELEMENTS AND PROCEDURES Three tests were conducted on 8-inch...weights. A 14,000-lb crane counterweight was used for the preload, applying a load of 7,000 lb to each one-third point on the plank. The drop weight was

A precise goniometer/tensiometer using a low cost single-board computer

NASA Astrophysics Data System (ADS)

Favier, Benoit; Chamakos, Nikolaos T.; Papathanasiou, Athanasios G.

2017-12-01

Measuring the surface tension and the Young contact angle of a droplet is extremely important for many industrial applications. Here, considering the booming interest for small and cheap but precise experimental instruments, we have constructed a low-cost contact angle goniometer/tensiometer, based on a single-board computer (Raspberry Pi). The device runs an axisymmetric drop shape analysis (ADSA) algorithm written in Python. The code, here named DropToolKit, was developed in-house. We initially present the mathematical framework of our algorithm and then we validate our software tool against other well-established ADSA packages, including the commercial ramé-hart DROPimage Advanced as well as the DropAnalysis plugin in ImageJ. After successfully testing for various combinations of liquids and solid surfaces, we concluded that our prototype device would be highly beneficial for industrial applications as well as for scientific research in wetting phenomena compared to the commercial solutions.

Energy dissipation in twelve-foot broken-back culverts using laboratory models : final report.

DOT National Transportation Integrated Search

2013-09-01

This report represents Phase IV of broken-back culverts with a drop of 12 feet. The first phase of this research was performed with a drop of 24 feet, the second phase of this research was carried with for a drop of 6 feet, and the third phase of thi...

Effect of Autologous Serum Eye Drops in Patients with Sjögren Syndrome-related Dry Eye: Clinical and In Vivo Confocal Microscopy Evaluation of the Ocular Surface.

PubMed

Semeraro, Francesco; Forbice, Eliana; Nascimbeni, Giuseppe; Taglietti, Marco; Romano, Vito; Guerra, Germano; Costagliola, Ciro

To evaluate in vivo changes after therapy using autologous serum (AS) eye drops in Sjögren's syndrome (SS)-related dry eyes by confocal microscopy. In this study, 24 patients with SS-related dry eyes [12 in AS eye drop therapy and 12 in artificial tear (AT) therapy] and 24 healthy volunteers were recruited. Ocular Surface Disease Index (OSDI), central corneal thickness, tear film, break-up time, corneal and conjunctival staining, Schirmer's test and corneal confocal microscopy were investigated. Tear production, tear stability, corneal staining, inflammation, and central corneal thickness, Langherans cells, activated keratocytes, intermediate epithelial cell density, nerve tortuosity, number of sub-basal nerve branches, and number of bead-like formations differed between patients and controls (p<0.0001). The AT and AS groups differed in the OSDI, number of branches, and number of beadings (p<0.0001). AS eye drops improve symptoms and confocal microscopy findings in SS-related dry eyes. Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

The effect of roof strength on reducing occupant injury in rollovers.

PubMed

Herbst, Brian; Forrest, Steve; Orton, Tia; Meyer, Steven E; Sances, Anthony; Kumaresan, Srirangam

2005-01-01

Roof crush occurs and potentially contributes to serious or fatal occupant injury in 26% of rollovers. It is likely that glazing retention is related to the degree of roof crush experienced in rollover accidents. Occupant ejection (including partial ejection) is the leading cause of death and injury in rollover accidents. In fatal passenger car accidents involving ejection, 34% were ejected through the side windows. Side window glass retention during a rollover is likely to significantly reduce occupant ejections. The inverted drop test methodology is a test procedure to evaluate the structural integrity of roofs under loadings similar to those seen in real world rollovers. Recent testing on many different vehicle types indicates that damage consistent with field rollover accidents can be achieved through inverted drop testing at very small drop heights. Drop test comparisons were performed on 16 pairs of vehicles representing a large spectrum of vehicle types. Each vehicle pair includes a production vehicle and a vehicle with a reinforced roof structure dropped under the same test conditions. This paper offers several examples of post-production reinforcements to roof structures that significantly increase the crush resistance of the roof as measured by inverted drop tests. These modifications were implemented with minimal impact on vehicle styling, interior space and visual clearances. The results of these modifications indicate that roof crush can be mitigated by nearly an order of magnitude, as roof crush was reduced by 44-91% with only a 1-2.3% increase in vehicle weight. Additionally, this paper analyzes the glazing breakage patterns in the moveable tempered side windows on the side adjacent to the vehicle impact point in the inverted drop tests. A comparison is made between the production vehicles and the reinforced vehicles in order to determine if the amount roof crush is related to glazing integrity in the side windows. Lastly, two drop test pairs, performed with Hybrid III test dummies, indicates that the reduction of roof crush resulted in a direct reduction in neck loading and therefore an increase in occupant protection.

Impact Testing and Simulation of a Sinusoid Foam Sandwich Energy Absorber

NASA Technical Reports Server (NTRS)

Jackson, Karen E.; Fasanella, Edwin L; Littell, Justin D.

2015-01-01

A sinusoidal-shaped foam sandwich energy absorber was developed and evaluated at NASA Langley Research Center through multi-level testing and simulation performed under the Transport Rotorcraft Airframe Crash Testbed (TRACT) research project. The energy absorber, designated the "sinusoid," consisted of hybrid carbon- Kevlar® plain weave fabric face sheets, two layers for each face sheet oriented at +/-45deg with respect to the vertical or crush direction, and a closed-cell ELFOAM(TradeMark) P200 polyisocyanurate (2.0-lb/ft3) foam core. The design goal for the energy absorber was to achieve an average floor-level acceleration of between 25- and 40-g during the full-scale crash test of a retrofitted CH-46E helicopter airframe, designated TRACT 2. Variations in the design were assessed through quasi-static and dynamic crush testing of component specimens. Once the design was finalized, a 5-ft-long subfloor beam was fabricated and retrofitted into a barrel section of a CH-46E helicopter. A vertical drop test of the barrel section was conducted onto concrete to evaluate the performance of the energy absorber prior to retrofit into TRACT 2. Finite element models were developed of all test articles and simulations were performed using LSDYNA ®, a commercial nonlinear explicit transient dynamic finite element code. Test analysis results are presented for the sinusoid foam sandwich energy absorber as comparisons of load-displacement and acceleration-time-history responses, as well as predicted and experimental structural deformations and progressive damage for each evaluation level (component testing through barrel section drop testing).

Accomplishments of the Abrupt Wing Stall (AWS) Program and Future Research Requirements

NASA Technical Reports Server (NTRS)

Hall, Robert M.; Woodson, Shawn H.; Chambers, Joseph R.

2003-01-01

The Abrupt Wing Stall (AWS) Program has addressed the problem of uncommanded lateral motions, such as wing drop and wing rock, at transonic speeds. The genesis of this Program was the experience of the F/A-18E/F Program in the late 199O's, when wing drop was discovered in the heart of the maneuver envelope for the pre-production aircraft. While the F/A-18E/F problem was subsequently corrected by a leading-edge flap scheduling change and the addition of a porous door to the wing fold fairing, the AWS Program was initiated as a national response to the lack of technology readiness available at the time of the F/A-18E/F Development Program. The AWS Program objectives were to define causal factors for the F/A-18E/F experience, to gain insights into the flow physics associated with wing drop, and to develop methods and analytical tools so that future programs could identify this type of problem before going to flight test. The paper reviews, for the major goals of the AWS Program, the status of the technology before the program began, the program objectives, accomplishments, and impacts. Lessons learned are presented for the benefit of future programs that must assess whether a vehicle will have uncommanded lateral motions before going to flight test. Finally, recommended future research needs are presented in light of the AWS Program experience.

Research on ignition and flame spread of solid materials in Japan

NASA Technical Reports Server (NTRS)

Ito, Kenichi; Fujita, Osamu

1995-01-01

Fire safety is one of the main concerns for crewed missions such as the space station. Materials used in spacecraft may burn even if metalic. There are severe restrictions on the materials used in spacecraft from the view of fire safety. However, such restrictions or safety standards are usually determined based on experimental results under normal gravity, despite large differences between the phenomena under normal and microgravity. To evaluate the appropriateness of materials for use in space, large amount of microgravity fire-safety combustion data is urgently needed. Solid material combustion under microgravity, such as ignition and flame spread, is a relatively new research field in Japan. As the other reports in this workshop describe, most of microgravity combustion research in Japan is droplet combustion as well as some research on gas phase combustion. Since JAMIC, the Japan Microgravity Center, (which offers 10 seconds microgravity time) opened in 1992, microgravity combustion research is robust, and many drop tests relating to solid combustion (paper combustion, cotton string combustion, metal combustion with Aluminium or Magnesium) have been performed. These tests proved that the 10 seconds of microgravity time at JAMIC is useful for solid combustion research. Some experiments were performed before JAMIC opened. For example, latticed paper was burned under microgravity by using a 50 m drop tower to simulate porous material combustion under microgravity. A 50 m tower provides only 2 seconds microgravity time however, and it was not long enough to investigate the solid combustion phenomena.

49 CFR 178.603 - Drop test.

Code of Federal Regulations, 2010 CFR

2010-10-01

... drums, Plastic drums and Jerricans, Composite packagings which are in the shape of a drum Six—(three for... of natural wood, Plywood boxes, Reconstituted wood boxes, Fiberboard boxes, Plastic boxes, Steel or... Administrator. (c) Special preparation of test samples for the drop test. (1) Testing of plastic drums, plastic...

14 CFR 29.501 - Ground loading conditions: landing gear with skids.

Code of Federal Regulations, 2012 CFR

2012-01-01

... exceed those obtained in a drop test of the gear with— (i) A drop height of 1.5 times that specified in § 29.725; and (ii) An assumed rotor lift of not more than 1.5 times that used in the limit drop tests...) The ground reactions rationally distributed along the bottom of the skid tube. (b) Vertical reactions...

14 CFR 27.501 - Ground loading conditions: landing gear with skids.

Code of Federal Regulations, 2012 CFR

2012-01-01

... exceed those obtained in a drop test of the gear with— (i) A drop height of 1.5 times that specified in § 27.725; and (ii) An assumed rotor lift of not more than 1.5 times that used in the limit drop tests...) The ground reactions rationally distributed along the bottom of the skid tube. (b) Vertical reactions...

14 CFR 29.501 - Ground loading conditions: landing gear with skids.

Code of Federal Regulations, 2014 CFR

2014-01-01

... exceed those obtained in a drop test of the gear with— (i) A drop height of 1.5 times that specified in § 29.725; and (ii) An assumed rotor lift of not more than 1.5 times that used in the limit drop tests...) The ground reactions rationally distributed along the bottom of the skid tube. (b) Vertical reactions...

14 CFR 27.501 - Ground loading conditions: landing gear with skids.

Code of Federal Regulations, 2014 CFR

2014-01-01

... exceed those obtained in a drop test of the gear with— (i) A drop height of 1.5 times that specified in § 27.725; and (ii) An assumed rotor lift of not more than 1.5 times that used in the limit drop tests...) The ground reactions rationally distributed along the bottom of the skid tube. (b) Vertical reactions...

14 CFR 29.501 - Ground loading conditions: landing gear with skids.

Code of Federal Regulations, 2013 CFR

2013-01-01

... exceed those obtained in a drop test of the gear with— (i) A drop height of 1.5 times that specified in § 29.725; and (ii) An assumed rotor lift of not more than 1.5 times that used in the limit drop tests...) The ground reactions rationally distributed along the bottom of the skid tube. (b) Vertical reactions...

14 CFR 27.501 - Ground loading conditions: landing gear with skids.

Code of Federal Regulations, 2013 CFR

2013-01-01

... exceed those obtained in a drop test of the gear with— (i) A drop height of 1.5 times that specified in § 27.725; and (ii) An assumed rotor lift of not more than 1.5 times that used in the limit drop tests...) The ground reactions rationally distributed along the bottom of the skid tube. (b) Vertical reactions...

Review on drop towers and long drop tubes

NASA Technical Reports Server (NTRS)

Bayuzick, R. J.; Hofmeister, W. H.; Robinson, M. B.

1987-01-01

A drop tube is an enclosure in which a molten sample can be solidified while falling; three such large tubes are currently in existence, all at NASA research facilities, and are engaged in combustion and fluid physics-related experiments rather than in materials research. JPL possesses smaller tubes, one of which can be cryogenically cooled to produce glass and metal microshells. A new small drop tube will soon begin operating at NASA Lewis that is equipped with four high-speed two-color pyrometers spaced equidistantly along the column.

Clean Room in the Zero Gravity Research Facility

NASA Image and Video Library

1968-07-21

A technician prepares a test sample in the Zero Gravity Research Facility clean room at the National Aeronautics and Space Administration (NASA) Lewis Research Center. The Zero Gravity Research Facility contained a drop tower which provided five seconds of microgravity during freefall in its 450-foot deep vacuum chamber. The facility has been used for a variety of studies relating to the behavior of fluids and flames in microgravity. During normal operations, a cylindrical 3-foot diameter and 11-foot long vehicle was used to house the experiments, instrumentation, and high speed cameras. The 4.5-foot long and 1.5-foot wide rectangular vehicle, seen in this photograph, was used less frequently. A 3-foot diameter orb was used for the special ten-second drops in which the package was pneumatically shot to the top of the tower then dropped. The facility also contained a control room, shop offices, tool and equipment rooms, and this clean room. The 242.5-foot long and 19.5-foot wide clean room was equipped with specialized cleaning equipment. In the 1960s the room was rated as a class 10,000 clean room, but I was capable of meeting the class 100 requirements. The room included a fume hood, ultrasonic cleaner, and a laminar flow station which operated as a class 100 environment. The environment in the clean room was maintained at 71° F and a relative humidity of 45- percent.

Modified Drop Tower Impact Tests for American Football Helmets.

PubMed

Rush, G Alston; Prabhu, R; Rush, Gus A; Williams, Lakiesha N; Horstemeyer, M F

2017-02-19

A modified National Operating Committee on Standards for Athletic Equipment (NOCSAE) test method for American football helmet drop impact test standards is presented that would provide better assessment of a helmet's on-field impact performance by including a faceguard on the helmet. In this study, a merger of faceguard and helmet test standards is proposed. The need for a more robust systematic approach to football helmet testing procedures is emphasized by comparing representative results of the Head Injury Criterion (HIC), Severity Index (SI), and peak acceleration values for different helmets at different helmet locations under modified NOCSAE standard drop tower tests. Essentially, these comparative drop test results revealed that the faceguard adds a stiffening kinematic constraint to the shell that lessens total energy absorption. The current NOCSAE standard test methods can be improved to represent on-field helmet hits by attaching the faceguards to helmets and by including two new helmet impact locations (Front Top and Front Top Boss). The reported football helmet test method gives a more accurate representation of a helmet's performance and its ability to mitigate on-field impacts while promoting safer football helmets.

Pegasus Rocket Booster Being Prepared for X-43A/Hyper-X Flight Test

NASA Image and Video Library

1999-08-25

Technicians prepare a Pegasus rocket booster for flight tests with the X-43A "Hypersonic Experimental Vehicle," or "Hyper-X." The X-43A, which will be attached to the Pegasus booster and drop launched from NASA's B-52 mothership, was developed to research dual-mode ramjet/scramjet propulsion system at speeds from Mach 7 up to Mach 10 (7 to 10 times the speed of sound, which varies with temperature and altitude).

Micro-explosion of compound drops

NASA Astrophysics Data System (ADS)

Chen, Chun-Kuei; Lin, Ta-Hui

2014-08-01

Introducing water into spray combustion systems, by either water-in-oil emulsification or supplementary water injection, is one of the major techniques for combustion improvement and NOx reduction. Plentiful researches are available on combustion of water-in-oil emulsion fuel drops. The emulsified liquid is a heterogeneous mixture of immiscible liquids. One component forms the continuous phase and the other component forms the discrete phase. The discrete phase consists of globules of the one fluid that are suspended in the continuous phase fluid. Water-in-oil emulsions are commonly considered for combustion applications because emulsions can result in micro-explosion, thereby reducing the average drop diameter to enhance liquid vaporization, and suppressing the formation of soot and NOx. However, the water addition generally does not exceed about 20% for smooth engine operations[!, 21. The combustion characteristics and micro-explosion of emulsion drop were studied by many researchers. The micro-explosion of water in fuel emulsion drops was caused by very fast growth of superheated water vapor bubbles, its superheat limits must be lower than the boiling point temperature of the fuel. These bubbles were primarily governed by the pressure difference between the superheated vapor and the liquid, and by the inertia imparted to the liquid by the motion of the bubble surface[3 6 In this study, we used a coaxial nozzle to generation the multi-component drop. The different type of water-in-oil fuel drops called the compound drops. Unlike an emulsion drop, a compound drop consists of a water core and a fuel shell, which can originate from the phase separation of emulsion[7, 81 or a water drop colliding with a fuel drop[9, 101 Burning and micro-explosion of compound drops have been found to be distinct from those of emulsion drops[9-111 Wang et al.[9 , 101 studied the combustion characteristics of collision merged alkane-water drops. The merged drops appeared in adhesive and inserted manners. The drop ignition delay time increased with increasing water content. The average burning rate of alkane-water drops decreased with increasing water content. In the burning process, hexadecane-water drops exhibited flash vaporization or flame extinction. Heterogeneous explosion was occasionally observed in drops with trapped air bubbles. The air bubbles were assumed to be the nucleation points of the heterogeneous explosions. Chen and Lin[11 studied the characteristics of water-in-dodecane compound drop with different water content, diameter of drop and environmental oxygen concentration. The vaporization rate increased with increasing environmental oxygen concentration. The compound drops micro-exploded during the burning process in a random way. The number of micro-explosions was majorly influenced by drop diameter, followed by environmental oxygen concentration. Water content had a weaker effect on micro-explosion. As available literature and research results of compound drop burning are scarce, their combustion and micro-explosion behaviors are still poorly understood. In this regard, we changed the drop nature as compound drops to study their combustion characteristics and micro-explosion phenomena.

Factors Affecting Planting Depth and Standing of Rice Seedling in Parachute Rice Transplanting

NASA Astrophysics Data System (ADS)

Astika, I. W.; Subrata, I. D. M.; Pramuhadi, G.

2018-05-01

Parachute rice transplanting is a simple and practical rice transplanting method. It can be done manually or mechanically, with various possible designs of machines or tools. This research aimed at quantitatively formulating related factors to the planting depth and standing of rice seedling. Parachute seedlings of rice were grown at several sizes of parachute soil bulb sizes. The trays were specially designed with a 3D printer having bulb sizes 7, 8, 9, 10 mm in square sides and 15 mm depth. At seedling ages of 8-12 days after sowing the seedling bulbs were drops into puddled soil. Soil hardness was set at 3 levels of hardness, measured in hardness index using golf ball test. Angle of dropping was set at 3 levels: 0°, 30°and 45° from the vertical axis. The height of droppings was set at 100 cm, 75 cm, and 50 cm. The relationship between bulb size, height of dropping, soil hardness, dropping angle and planting depth was formulated with ANN. Most of input variables did not significantly affect the planting depth, except that hard soil significantly differs from mild soil and soft soil. The dropping also resulted in various positions of the planted seedlings: vertical standing, sloped, and falling. However, at any position of the planted seedlings, the seedlings would recover themselves into normally vertical position. With this result, the design of planting machinery, as well as the manual planting operation, can be made easier.

Academic Fatalism: Applying Durkheim's Fatalistic Suicide Typology to Student Drop-Out and the Climate of Higher Education

ERIC Educational Resources Information Center

Godor, Brian P.

2017-01-01

Student drop-out remains a critical issue facing educational professionals. For higher education, the vast research in the past 40 years has been influenced by the work of Tinto and his model of student persistence. In this model are several elements that have proven to sharpen the focus of student drop-out research such as the concept of…

Research of metal solidification in zero-g state. [test apparatus and instrumentation

NASA Technical Reports Server (NTRS)

Aubin, W. M.; Larson, D., Jr.; Geschwind, G. I.

1973-01-01

An experiment test apparatus that allows metal melting and resolidification in the three seconds available during free fall in a drop tower was built and tested in the tower. Droplets (approximately 0.05 cm) of pure nickel and 1090 steel were prepared in this fashion. The apparatus, including instrumentation, is described. As part of the instrumentation, a method for measuring temperature-time histories of the free floating metal droplets was developed. Finally, a metallurgical analysis of the specimens prepared in the apparatus is presented.

Dynamic Finite Element Predictions for Mars Sample Return Cellular Impact Test #4

NASA Technical Reports Server (NTRS)

Fasanella, Edwin L.; Billings, Marcus D.

2001-01-01

The nonlinear finite element program MSC.Dytran was used to predict the impact pulse for (he drop test of an energy absorbing cellular structure. This pre-test simulation was performed to aid in the design of an energy absorbing concept for a highly reliable passive Earth Entry Vehicle (EEV) that will directly impact the Earth without a parachute. In addition, a goal of the simulation was to bound the acceleration pulse produced and delivered to the simulated space cargo container. EEV's are designed to return materials from asteroids, comets, or planets for laboratory analysis on Earth. The EEV concept uses an energy absorbing cellular structure designed to contain and limit the acceleration of space exploration samples during Earth impact. The spherical shaped cellular structure is composed of solid hexagonal and pentagonal foam-filled cells with hybrid graphite-epoxy/Kevlar cell walls. Space samples fit inside a smaller sphere at the enter of the EEV's cellular structure. The material models and failure criteria were varied to determine their effect on the resulting acceleration pulse. Pre-test analytical predictions using MSC.Dytran were compared with the test results obtained from impact test #4 using bungee accelerator located at the NASA Langley Research Center Impact Dynamics Research Facility. The material model used to represent the foam and the proper failure criteria for the cell walls were critical in predicting the impact loads of the cellular structure. It was determined that a FOAMI model for the foam and a 20% failure strain criteria for the cell walls gave an accurate prediction of the acceleration pulse for drop test #4.

Managing Challenges in a Multi Contractor Project

NASA Technical Reports Server (NTRS)

King, Ron

2011-01-01

The presentation provides a project description, describes the integrated product team, and review project challenges. The challenges include programmatic, technical, basic drop tests, heavy drop tests, C-17 envelope expansion, and Ares I-X.

14 CFR 31.27 - Strength.

Code of Federal Regulations, 2012 CFR

2012-01-01

... drop test height of 36 inches, or a drop test height that produces, upon impact, a velocity equal to the maximum vertical velocity determined in accordance with § 31.19, whichever is higher, must be used...

14 CFR 31.27 - Strength.

Code of Federal Regulations, 2013 CFR

2013-01-01

... drop test height of 36 inches, or a drop test height that produces, upon impact, a velocity equal to the maximum vertical velocity determined in accordance with § 31.19, whichever is higher, must be used...

14 CFR 31.27 - Strength.

Code of Federal Regulations, 2014 CFR

2014-01-01

... drop test height of 36 inches, or a drop test height that produces, upon impact, a velocity equal to the maximum vertical velocity determined in accordance with § 31.19, whichever is higher, must be used...

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

PubMed

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

2015-09-01

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

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

PubMed Central

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

2014-01-01

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

49 CFR 178.33b-7 - Design qualification test.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., each new design must be drop tested as follows: Three groups of twenty-five filled containers must be... 49 Transportation 2 2010-10-01 2010-10-01 false Design qualification test. 178.33b-7 Section 178... PACKAGINGS Specifications for Inside Containers, and Linings § 178.33b-7 Design qualification test. (a) Drop...

46 CFR 160.056-4 - Approval tests of prototype rescue boat.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 6 2011-10-01 2011-10-01 false Approval tests of prototype rescue boat. 160.056-4..., CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Rescue Boat § 160.056-4 Approval tests of prototype rescue boat. (a) Drop test. The rescue boat, fully equipped, shall be dropped, in a...

46 CFR 160.056-4 - Approval tests of prototype rescue boat.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 6 2012-10-01 2012-10-01 false Approval tests of prototype rescue boat. 160.056-4..., CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Rescue Boat § 160.056-4 Approval tests of prototype rescue boat. (a) Drop test. The rescue boat, fully equipped, shall be dropped, in a...

46 CFR 160.056-4 - Approval tests of prototype rescue boat.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 6 2014-10-01 2014-10-01 false Approval tests of prototype rescue boat. 160.056-4..., CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Rescue Boat § 160.056-4 Approval tests of prototype rescue boat. (a) Drop test. The rescue boat, fully equipped, shall be dropped, in a...

46 CFR 160.056-4 - Approval tests of prototype rescue boat.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 6 2013-10-01 2013-10-01 false Approval tests of prototype rescue boat. 160.056-4..., CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Rescue Boat § 160.056-4 Approval tests of prototype rescue boat. (a) Drop test. The rescue boat, fully equipped, shall be dropped, in a...

46 CFR 160.056-4 - Approval tests of prototype rescue boat.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 6 2010-10-01 2010-10-01 false Approval tests of prototype rescue boat. 160.056-4 Section 160.056-4 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT... tests of prototype rescue boat. (a) Drop test. The rescue boat, fully equipped, shall be dropped, in a...

49 CFR 178.603 - Drop test.

Code of Federal Regulations, 2012 CFR

2012-10-01

... the fourth sample). Fifth drop: On a corner (using the fifth sample). Bags—single-ply with a side seam...). Bags—single-ply without a side seam, or multi-ply Three—(two drops per bag) First drop: Flat on a wide...) For a bag, neither the outermost ply nor an outer packaging exhibits any damage likely to adversely...

49 CFR 173.465 - Type A packaging tests.

Code of Federal Regulations, 2011 CFR

2011-10-01

... quarters of each rim from a height of 0.3 m (1 foot). (5) The target for the free drop test must be a flat... Transport Package mass Kilograms (pounds) Free drop distance Meters (Feet) 15,000 (33,000) Mass 0.3 (1) (2... section must be preceded by a free drop from a height of 0.3 m (1 foot) on each corner, or in the case of...

Enhancing Injury Protection Capabilities of Army Combat Helmets

DTIC Science & Technology

2006-11-01

rate on each material’s energy attenuation characteristics, dynamic compression tests were conducted using a monorail drop tower conforming to ANSI...equipment. An Army combat helmet is fitted to the monorail drop tower (left). The variable weight, flat impactor (right) is fitted to the monorail ...3.3.1 Impact attenuation All impact tests were conducted using the USAARL vertical monorail drop tower (Figure 1, left). Impact sites along with

NASA Dryden Flight Research Center: We Fly What Others Only Imagine

NASA Technical Reports Server (NTRS)

Ennix-Sandhu, Kimberly

2006-01-01

A powerpoint presentation of NASA Dryden's historical and future flight programs is shown. The contents include: 1) Getting To Know NASA; 2) Our Namesake; 3) To Fly What Others Only Imagine; 4) Dryden's Mission: Advancing Technology and Science Through Flight; 5) X-1 The First of the Rocket-Powered Research Aircraft; 6) X-1 Landing; 7) Lunar Landing Research Vehicle (LLRV) Liftoff and Landing; 8) Linear Aerospike SR-71 Experiment (LASRE) Ground Test; 9) M2-F1 (The Flying Bathtub); 10) M2-F2 Drop Test; 11) Enterprise Space Shuttle Prototype; 12) Space Shuttle Columbia STS-1; 13) STS-114 Landing-August 2005; 14) Crew Exploration Vehicle (CEV); 15) What You Can Do To Succeed!; and 16) NASA Dryden Flight Research Center: This is What We Do!

Overview of the NASA Subsonic Rotary Wing Aeronautics Research Program in Rotorcraft Crashworthiness

NASA Technical Reports Server (NTRS)

Jackson, Karen E.; Kellas, Sotiris; Fuchs, Yvonne T.

2009-01-01

This paper provides an overview of rotorcraft crashworthiness research being conducted at NASA Langley Research Center under sponsorship of the Subsonic Rotary Wing (SRW) Aeronautics Program. The research is focused in two areas: development of an externally deployable energy attenuating concept and improved prediction of rotorcraft crashworthiness. The deployable energy absorber (DEA) is a composite honeycomb structure, with a unique flexible hinge design that allows the honeycomb to be packaged and remain flat until needed for deployment. The capabilities of the DEA have been demonstrated through component crush tests and vertical drop tests of a retrofitted fuselage section onto different surfaces or terrain. The research on improved prediction of rotorcraft crashworthiness is focused in several areas including simulating occupant responses and injury risk assessment, predicting multi-terrain impact, and utilizing probabilistic analysis methods. A final task is to perform a system-integrated simulation of a full-scale helicopter crash test onto a rigid surface. A brief description of each research task is provided along with a summary of recent accomplishments.

Overview of the NASA Subsonic Rotary Wing Aeronautics Research Program in Rotorcraft Crashworthiness

NASA Technical Reports Server (NTRS)

Jackson, Karen E.; Fuchs, Yvonne T.; Kellas, Sotiris

2008-01-01

This paper provides an overview of rotorcraft crashworthiness research being conducted at NASA Langley Research Center under sponsorship of the Subsonic Rotary Wing (SRW) Aeronautics Program. The research is focused in two areas: development of an externally deployable energy attenuating concept and improved prediction of rotorcraft crashworthiness. The deployable energy absorber (DEA) is a composite honeycomb structure, with a unique flexible hinge design that allows the honeycomb to be packaged and remain flat until needed for deployment. The capabilities of the DEA have been demonstrated through component crush tests and vertical drop tests of a retrofitted fuselage section onto different surfaces or terrain. The research on improved prediction of rotorcraft crashworthiness is focused in several areas including simulating occupant responses and injury risk assessment, predicting multi-terrain impact, and utilizing probabilistic analysis methods. A final task is to perform a system-integrated simulation of a full-scale helicopter crash test onto a rigid surface. A brief description of each research task is provided along with a summary of recent accomplishments.

A laboratory measurement of drop impact on a water surface in the presence of wind

NASA Astrophysics Data System (ADS)

Liu, Xinan; Liu, Ren

2014-11-01

The impact of single water drops on a water surface was studied experimentally in a wind tunnel. Water drops were generated from a needle oriented vertically from the top of the wind tunnel test section. After leaving the needle, the drops move downward due to gravity and downstream due to the effect of the wind, eventually impinging obliquely on the surface of a pool of water on the bottom of the test section. The vertical velocities of drops were about 2.0 m/s and the wind speeds varied from 0 to 6.4 m/s. The drop impacts were recorded simultaneously from the side and above with two high-speed movie cameras with frame rates of 1,000 Hz. Our measurements show that both wind speed and initial drop size dramatically affect the drop impacts and subsequent generation of crowns, secondary drops, stalks and ring waves. In the presence of wind, an asymmetric crown forms after the drop hits the water surface and secondary drops are generated from the fragmentation of the leeward side of the crown rim. This is followed by a stalk formation and ring waves at the location of the water drop impact. It is found that the stalks tilt to leeward and the ring waves in the windward direction are stronger than that in those in the leeward. This work is supported by National Science Foundation, Division of Ocean Sciences.

Static, Drop, and Flight Tests on Musselman Type Airwheels

NASA Technical Reports Server (NTRS)

Peck, William C; Beard, Albert P

1932-01-01

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

Scaling, clustering and avalanches for steel beads in an external magnetic field

NASA Astrophysics Data System (ADS)

Marquinez, Alyse; Thvedt, Ingrid; Lehman, S. Y.; Jacobs, D. T.

2011-03-01

We investigated avalanches using uniform 3mm steel spheres (``beads'') dropped onto a conical bead pile within a uniform magnetic field. The bead pile is built by pouring beads onto a circular base where the bottom layer of beads had been glued randomly. Beads are then individually dropped from a fixed height after which the pile is massed. This process is repeated for thousands of bead drops. By measuring the number of avalanches of a given size that occurred during the experiment, the resulting avalanche size distribution was compared to a power law description as predicted by self-organized criticality. As the magnetic field intensity increased, the beads clustered to give a larger angle of repose and we measured the change in the avalanche size distribution. The moments of the distribution give a sensitive test of mean-field theory as the universality class for these bead piles. We acknowledge support from Research Corporation and NSF-REU grant DMR 0649112.

Veterans at Risk: The Health Effects of Mustard Gas and Lewisite

DTIC Science & Technology

1993-01-01

to Mustard Gas During WWII Testing Programs 370 F. Summary of the Department of the Army Report: Use of Volunteers in Chemical Agent Research 378 Key...concentrations of mustard agents or Lewisite in gas chambers or in field exercises over contaminated ground areas. The human subjects had experienced a...wide range of exposures to mustard agents or Lewisite, from mild (a drop of agent on the arm in "patch" tests) to quite severe (repeated gas chamber

NASA Test Conductor Monitoring DIME competition

NASA Technical Reports Server (NTRS)

2002-01-01

A NASA test conductor at the top of the 2.2-second Drop Tower monitors a student lecture at a lower level. This was part of the Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

Characterisation of anti-erosive properties of nanocomposite coatings by the methods of sclerometry

NASA Astrophysics Data System (ADS)

Kudryakov, O. V.; Varavka, V. N.; Ilyasov, V. V.

2017-05-01

Results of research of coatings of the different metal-ceramics systems are given. Coatings were received by ion-plasma sedimentation in vacuum in the form of multilayered composite material, which had a thickness of layers within nanometric range. Selection of composite systems is determined by applied research problem - namely designing of the anti-erosive coatings durable in the condition of drop impingement impacts. For this purpose the sclerometric studies, the bench erosive tests and optimization of the obtained data were done.

Mineback Stimulation Research Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warpinski, N.R.

The objective of the Mineback Stimulation Research Experiments is to improve hydraulic fracture stimulation technology by providing an in situ laboratory where basic processes and mechanisms that control and influence fracture propagation can be observed, measured and understood. While previous tests have been instrumental in providing an understanding of the mechanisms controlling fracture height, current experiments are focused on fluid flow through the created fracture and the associated pressure drops and crack widths. Work performed, accomplishments and future plans are presented. 7 refs., 2 figs.

49 CFR 178.603 - Drop test.

Code of Federal Regulations, 2014 CFR

2014-10-01

... (using the fourth sample). Fifth drop: On a corner (using the fifth sample). Bags—single-ply with a side... samples). Bags—single-ply without a side seam, or multi-ply Three—(two drops per bag) First drop: Flat on... the drum is no longer sift-proof; (3) For a bag, neither the outermost ply nor an outer packaging...

Combining spray nozzle simulators with meshes: characterization of rainfall intensity and drop properties

NASA Astrophysics Data System (ADS)

Carvalho, Sílvia C. P.; de Lima, João L. M. P.; de Lima, M. Isabel P.

2013-04-01

Rainfall simulators can be a powerful tool to increase our understanding of hydrological and geomorphological processes. Nevertheless, rainfall simulators' design and operation might be rather demanding, for achieving specific rainfall intensity distributions and drop characteristics. The pressurized simulators have some advantages over the non-pressurized simulators: drops do not rely on gravity to reach terminal velocity, but are sprayed out under pressure; pressurized simulators also yield a broad range of drop sizes in comparison with drop-formers simulators. The main purpose of this study was to explore in the laboratory the potential of combining spray nozzle simulators with meshes in order to change rainfall characteristics (rainfall intensity and diameters and fall speed of drops). Different types of spray nozzles were tested, such as single full-cone and multiple full-cone nozzles. The impact of the meshes on the simulated rain was studied by testing different materials (i.e. plastic and steel meshes), square apertures and wire thicknesses, and different vertical distances between the nozzle and the meshes underneath. The diameter and fall speed of the rain drops were measured using a Laser Precipitation Monitor (Thies Clima). The rainfall intensity range and coefficients of uniformity of the sprays and the drop size distribution, fall speed and kinetic energy were analysed. Results show that when meshes intercept drop trajectories the spatial distribution of rainfall intensity and the drop size distribution are affected. As the spray nozzles generate typically small drop sizes and narrow drop size distributions, meshes can be used to promote the formation of bigger drops and random their landing positions.

Dropping out from School. Policy Brief Number 8

ERIC Educational Resources Information Center

Hunt, Frances

2009-01-01

While initial access to education is increasing in many countries, drop out rates continue to be high. This seriously affects MDG and EFA goals around educational access. This briefing paper looks at the issue of dropping out from school. It is based on the CREATE Pathways to Access Research Monograph, "Dropping out from school: a cross…

Tracking Drop-out Students in Palestinian Refugee Camps in Lebanon

ERIC Educational Resources Information Center

Al-Hroub, Anies

2015-01-01

This research paper examines the perceptions of students on the school drop-out problem in Palestinian refugee camps in Lebanon regarding (a) the social and economic causes associated with the phenomenon of school drop-out; (b) the educational policies and practices used in UNRWA schools and their relationship to student drop-out; and (c) the role…

Critical point wetting drop tower experiment

NASA Technical Reports Server (NTRS)

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

1984-01-01

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

Modeling of atomization and distribution of drop-liquid fuel in unsteady swirling flows in a combustion chamber and free space

NASA Astrophysics Data System (ADS)

Sviridenkov, A. A.; Toktaliev, P. D.; Tretyakov, V. V.

2018-03-01

Numerical and experimental research of atomization and propagation of drop-liquid phase in swirling flow behind the frontal device of combustion chamber was performed. Numerical procedure was based on steady and unsteady Reynolds equations solution. It's shown that better agreement with experimental data could be obtained with unsteady approach. Fractional time step method was implemented to solve Reynolds equations. Models of primary and secondary breakup of liquid fuel jet in swirling flows are formulated and tested. Typical mean sizes of fuel droplets for base operational regime of swirling device and combustion chamber were calculated. Comparison of main features of internal swirling flow in combustion chamber with unbounded swirling flow was made.

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

NASA Technical Reports Server (NTRS)

1995-01-01

A 4-foot-long model of NASA's X-38, an experimental crew return vehicle, glides to earth after being dropped from a Cessna aircraft in late 1995. The model was used to test the ram-air parafoil landing system, which could allow for accurate and controlled landings of an emergency Crew Return Vehicle spacecraft returning to Earth. The X-38 Crew Return Vehicle (CRV) research project is designed to develop the technology for a prototype emergency crew return vehicle, or lifeboat, for the International Space Station. The project is also intended to develop a crew return vehicle design that could be modified for other uses, such as a joint U.S. and international human spacecraft that could be launched on the French Ariane-5 Booster. The X-38 project is using available technology and off-the-shelf equipment to significantly decrease development costs. Original estimates to develop a capsule-type crew return vehicle were estimated at more than $2 billion. X-38 project officials have estimated that development costs for the X-38 concept will be approximately one quarter of the original estimate. Off-the-shelf technology is not necessarily 'old' technology. Many of the technologies being used in the X-38 project have never before been applied to a human-flight spacecraft. For example, the X-38 flight computer is commercial equipment currently used in aircraft and the flight software operating system is a commercial system already in use in many aerospace applications. The video equipment for the X-38 is existing equipment, some of which has already flown on the space shuttle for previous NASA experiments. The X-38's primary navigational equipment, the Inertial Navigation System/Global Positioning System, is a unit already in use on Navy fighters. The X-38 electromechanical actuators come from previous joint NASA, U.S. Air Force, and U.S. Navy research and development projects. Finally, an existing special coating developed by NASA will be used on the X-38 thermal tiles to make them more durable than those used on the space shuttles. The X-38 itself was an unpiloted lifting body designed at 80 percent of the size of a projected emergency crew return vehicle for the International Space Station, although two later versions were planned at 100 percent of the CRV size. The X-38 and the actual CRV are patterned after a lifting-body shape first employed in the Air Force-NASA X-24 lifting-body project in the early to mid-1970s. The current vehicle design is base lined with life support supplies for about nine hours of orbital free flight from the space station. It's landing will be fully automated with backup systems which allow the crew to control orientation in orbit, select a deorbit site, and steer the parafoil, if necessary. The X-38 vehicles (designated V131, V132, and V-131R) are 28.5 feet long, 14.5 feet wide, and weigh approximately 16,000 pounds on average. The vehicles have a nitrogen-gas-operated attitude control system and a bank of batteries for internal power. The actual CRV to be flown in space was expected to be 30 feet long. The X-38 project is a joint effort between the Johnson Space Center, Houston, Texas (JSC), Langley Research Center, Hampton, Virginia (LaRC) and Dryden Flight Research Center, Edwards, California (DFRC) with the program office located at JSC. A contract was awarded to Scaled Composites, Inc., Mojave, California, for construction of the X-38 test airframes. The first vehicle was delivered to the JSC in September 1996. The vehicle was fitted with avionics, computer systems and other hardware at Johnson. A second vehicle was delivered to JSC in December 1996. Flight research with the X-38 at Dryden began with an unpiloted captive-carry flight in which the vehicle remained attached to its future launch vehicle, Dryden's B-52 008. There were four captive flights in 1997 and three in 1998, plus the first drop test on March 12, 1998, using the parachutes and parafoil. Further captive and drop tests occurred in 1999. In March 2000 Vehicle 132 completed its third and final free flight in the highest, fastest, and longest X-38 flight to date. It was released at an altitude of 39,000 feet and flew freely for 45 seconds, reaching a speed of over 500 miles per hour before deploying its parachutes for a landing on Rogers Dry Lakebed. In the drop tests, the X-38 vehicles have been autonomous after airlaunch from the B-52. After they deploy the parafoil, they have remained autonomous, but there is also a manual mode with controls from the ground.

Radiative Ignition and the Transition to Flame Spread Investigated in the Japan Microgravity Center's 10-sec Drop Shaft

NASA Technical Reports Server (NTRS)

1996-01-01

The Radiative Ignition and Transition to Spread Investigation (RITSI) is a shuttle middeck Glovebox combustion experiment developed by the NASA Lewis Research Center, the National Institute for Standards and Technology (NIST), and Aerospace Design and Fabrication (ADF). It is scheduled to fly on the third United States Microgravity Payload (USMP-3) mission in February 1996. The objective of RITSI is to experimentally study radiative ignition and the subsequent transition to flame spread in low gravity in the presence of very low speed air flows in two- and three-dimensional configurations. Toward this objective, a unique collaboration between NASA, NIST, and the University of Hokkaido was established to conduct 15 science and engineering tests in Japan's 10-sec drop shaft. For these tests, the RITSI engineering hardware was mounted in a sealed chamber with a variable oxygen atmosphere. Ashless filter paper was ignited during each drop by a tungsten-halogen heat lamp focused on a small spot in the center of the paper. The flame spread outward from that point. Data recorded included fan voltage (a measure of air flow), radiant heater voltage (a measure of radiative ignition energy), and surface temperatures (measured by up to three surface thermocouples) during ignition and flame spread.

Experimental Research on Thermocapillary-Buoyancy Migration Interaction of Axisymmetric Two Drops by Using Digital Holographic Interferometry

NASA Astrophysics Data System (ADS)

Zhang, Shuoting; Duan, Li; Kang, Qi

2018-05-01

The migration and interaction of axisymmetric two drops in a vertical temperature gradient is investigated experimentally on the ground. A silicon oil is used as the continuous phase, and a water-ethanol mixture is used as the drop phase, respectively. The migration and interaction of two drops, under the combined effects of buoyancy and thermocapillary, is recorded by a digital holographic interferometry measurement in the experiment to analyse the velocities and temperature distribution of the drops. As a result, when two drops migrate together, the drop affects the other drop by perturbing the temperature field around itself. For the leading drop, the velocity is faster than the one of the isolated drop, and the maximum of the interfacial temperature distribution is larger than the one of the isolated drop. For the trailing drop, the velocity is slower than the one of the isolated drop, and the maximum of the interfacial temperature distribution is less than the one of the isolated drop. The influence of the dimensionless initial distance between the drop centres to the drop migration is discussed in detail in this study.

Marshall Space Flight Center's Impact Testing Facility Capabilities

NASA Technical Reports Server (NTRS)

Evans, Steve; Finchum, Andy; Hubbs, Whitney; Gray, Perry

2008-01-01

Marshall Space Flight Center's (MSFC) Impact Testing Facility (ITF) serves as an important installation for space and missile related materials science research. The ITF was established and began its research in spacecraft debris shielding in the early 1960s, then played a major role in the International Space Station debris shield development. As NASA became more interested in launch debris and in-flight impact concerns, the ITF grew to include research in a variety of impact genres. Collaborative partnerships with the DoD led to a wider range of impact capabilities being relocated to MSFC as a result of the closure of Particle Impact Facilities in Santa Barbara, California, The Particle Impact Facility had a 30 year history in providing evaluations of aerospace materials and components during flights through rain, ice, and solid particle environments at subsonic through hypersonic velocities. The facility's unique capabilities were deemed a 'National Asset' by the DoD, The ITF now has capabilities including environmental, ballistic, and hypervelocity impact testing utilizing an array of air, powder, and two-stage light gas guns to accommodate a variety of projectile and target types and sizes. Relocated test equipment was dated and in need of upgrade. Numerous upgrades including new instrumentation, triggering circuitry, high speed photography, and optimized sabot designs have been implemented. Other recent research has included rain drop demise characterization tests to obtain data for inclusion in on-going model development. Future ITF improvements will be focused on continued instrumentation and performance enhancements. These enhancements will allow further, more in-depth, characterization of rain drop demise characterization and evaluation of ice crystal impact. Performance enhancements also include increasing the upper velocity limit of the current environmental guns to allow direct environmental simulation for missile components. The current and proposed ITF capabilities range from rain to micrometeoroids allowing the widest test parameter range possible for materials investigations in support of space, atmospheric, and ground environments. These test capabilities including hydrometeor, single/multi-particle, ballistic gas guns, exploding wire gun, and light gas guns combined with Smooth Particle Hydrodynamics Code (SPHC) simulations represent the widest range of impact test capabilities in the country.

Marshall Space Flight Center's Impact Testing Facility Capabilities

NASA Technical Reports Server (NTRS)

Evans, Steve; Finchum, Andy; Hubbs, Whitney

2008-01-01

Marshall Space Flight Center's (MSFC) Impact Testing Facility (ITF) serves as an important installation for space and missile related materials science research. The ITF was established and began its research in spacecraft debris shielding in the early 1960% then played a major role in the International Space Station debris shield development. As NASA became more interested in launch debris and in-flight impact concerns, the ITF grew to include research in a variety of impact genres. Collaborative partnerships with the DoD led to a wider range of impact capabilities being relocated to MSFC as a result of the closure of Particle Impact Facilities in Santa Barbara, California. The Particle Impact Facility had a 30 year history in providing evaluations of aerospace materials and components during flights through rain, ice, and solid particle environments at subsonic through hypersonic velocities. The facility's unique capabilities were deemed a "National Asset" by the DoD. The ITF now has capabilities including environmental, ballistic, and hypervelocity impact testing utilizing an array of air, powder, and two-stage light gas guns to accommodate a variety of projectile and target types and sizes. Relocated test equipment was dated and in need of upgrade. Numerous upgrades including new instrumentation, triggering circuitry, high speed photography, and optimized sabot designs have been implemented. Other recent research has included rain drop demise characterization tests to obtain data for inclusion in on-going model development. Future ITF improvements will be focused on continued instrumentation and performance enhancements. These enhancements will allow further, more in-depth, characterization of rain drop demise characterization and evaluation of ice crystal impact. Performance enhancements also include increasing the upper velocity limit of the current environmental guns to allow direct environmental simulation for missile components. The current and proposed ITF capabilities range from rain to micrometeoroids allowing the widest test parameter range possible for materials investigations in support of space, atmospheric, and ground environments. These test capabilities including hydrometeor, single/multi-particle, ballistic gas grins, exploding wire gun, and light gas guns combined with Smooth Particle Hydrodynamics Code (SPHC) simulations represent the widest range of impact test capabilities in the country.

Three-dimensional modeling of diesel engine intake flow, combustion and emissions-2

NASA Technical Reports Server (NTRS)

Reitz, R. D.; Rutland, C. J.

1993-01-01

A three-dimensional computer code, KIVA, is being modified to include state-of-the-art submodels for diesel engine flow and combustion. Improved and/or new submodels which have already been implemented and previously reported are: wall heat transfer with unsteadiness and compressibility, laminar-turbulent characteristic time combustion with unburned HC and Zeldo'vich NO(x), and spray/wall impingement with rebounding and sliding drops. Progress on the implementation of improved spray drop drag and drop breakup models, the formulation and testing of a multistep kinetics ignition model, and preliminary soot modeling results are described. In addition, the use of a block structured version of KIVA to model the intake flow process is described. A grid generation scheme was developed for modeling realistic (complex) engine geometries, and computations were made of intake flow in the ports and combustion chamber of a two-intake-value engine. The research also involves the use of the code to assess the effects of subprocesses on diesel engine performance. The accuracy of the predictions is being tested by comparisons with engine experiments. To date, comparisons were made with measured engine cylinder pressure, temperature and heat flux data, and the model results are in good agreement with the experiments. Work is in progress that will allow validation of in-cylinder flow and soot formation predictions. An engine test facility is described that is being used to provide the needed validation data. Test results were obtained showing the effect of injection rate and split injections on engine performance and emissions.

Phase segregation due to simultaneous migration and coalescence

NASA Technical Reports Server (NTRS)

Davis, Robert H.; Wang, Hua; Hawker, Debra

1994-01-01

Ground-based modeling and experiments have been performed on the interaction and coalescence of drops leading to macroscopic phase separation. The focus has been on gravity-induced motion, with research also initiated on thermocapillary motion of drops. The drop size distribution initially shifts toward larger drops with time due to coalescence, and then a back towards smaller drops due to the larger preferentially settling out. As a consequence, the phase separation rate initially increases with time and then decreases.

Ultrahydrophobic water

NASA Astrophysics Data System (ADS)

Landgraf, J.; Kanitz, C.

2017-05-01

When a water drop falls on an oscillating soapy water surface it is observed that coalescence of the drop is inhibited because the drops are bouncing on the surface like on a trampoline. In our research we made experimental and theoretical investigations to an undeformable drop on a deformable bath. We described the vertical movement, predicted the critical bouncing threshold and also made experiments to the effects of an increased Weber number and the horizontal movement of the drop caused by a vertical movement.

Remotely operated high pressure valve protects test personnel

NASA Technical Reports Server (NTRS)

Howland, B. T.

1967-01-01

High pressure valve used in testing certain spacecraft systems is safely opened and closed by a remotely stationed operator. The valve is self-regulating in that if the incoming pressure drops below a desired value the valve will automatically close, warning the operator that the testing pressure has dropped to an undesired level.

14 CFR 29.725 - Limit drop test.

Code of Federal Regulations, 2013 CFR

2013-01-01

... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Landing Gear § 29.725 Limit drop test. The... energy absorbing devices or by the use of an effective mass. (c) Each landing gear unit must be tested in... to be absorbed by it. (d) When an effective mass is used in showing compliance with paragraph (b) of...

A kinematic wave model in Lagrangian coordinates incorporating capacity drop: Application to homogeneous road stretches and discontinuities

NASA Astrophysics Data System (ADS)

Yuan, Kai; Knoop, Victor L.; Hoogendoorn, Serge P.

2017-01-01

On freeways, congestion always leads to capacity drop. This means the queue discharge rate is lower than the pre-queue capacity. Our recent research findings indicate that the queue discharge rate increases with the speed in congestion, that is the capacity drop is strongly correlated with the congestion state. Incorporating this varying capacity drop into a kinematic wave model is essential for assessing consequences of control strategies. However, to the best of authors' knowledge, no such a model exists. This paper fills the research gap by presenting a Lagrangian kinematic wave model. "Lagrangian" denotes that the new model is solved in Lagrangian coordinates. The new model can give capacity drops accompanying both of stop-and-go waves (on homogeneous freeway section) and standing queues (at nodes) in a network. The new model can be applied in a network operation. In this Lagrangian kinematic wave model, the queue discharge rate (or the capacity drop) is a function of vehicular speed in traffic jams. Four case studies on links as well as at lane-drop and on-ramp nodes show that the Lagrangian kinematic wave model can give capacity drops well, consistent with empirical observations.

Testing the Auroral Current-Voltage Relation in Multiple Arcs

NASA Astrophysics Data System (ADS)

Cameron, T. G.; Knudsen, D. J.; Cully, C. M.

2013-12-01

The well-known current-voltage relation within auroral inverted-V regions [Knight, Planet. Space Sci., 21, 741, 1973] predicts current carried by an auroral flux tube given the total potential drop between a plasma-sheet source region and the ionosphere. Numerous previous studies have tested this relation using spacecraft that traverse auroral arcs at low (ionospheric) or mid altitudes. Typically, the potential drop is estimated at the peak of the inverted-V, and field-aligned current is estimated from magnetometer data; statistical information is then gathered over many arc crossings that occur over a wide range of source conditions. In this study we use electron data from the FAST satellite to examine the current-voltage relation in multiple arc sets, in which the key source parameters (plasma sheet density and temperature) are presumed to be identical. We argue that this approach provides a more sensitive test of the Knight relation, and we seek to explain remaining variability with factors other than source variability. This study is supported by a grant from the Natural Sciences and Engineering Research Council of Canada.

A Molecular Method to Detect Wound Cells in Bloodstains Resultant of Sharp Force Injuries for Crime Scene Reconstruction.

PubMed

Johnson, Donald J; Raymond, David E; Chen, Cynthia; Quon, Matthew; Lis, Julian; Choi, Mo Re; Lopez, Christopher; Han, Aileen; de Leon, Ray D; Bir, Cynthia

2018-05-01

Previous research by the authors on an animal model showed that bloodstains can contain additional information about their somatic origin in the form of wound cells. Bloodstains produced by a gunshot wound to the head were distinguished from bloodstains produced by a gunshot wound to the chest by testing the stains for a brain microRNA marker. In this study, the effectiveness of the technique was examined on blood drops shed externally from a stab wound to the liver of rat carcasses. Specifically, investigations were conducted on the liver microRNA marker, rno-mir-122-3p, with the QIAGEN miScript System, and PCR analysis. Between the two stabbing methods used, 67% of the scalpel blades and 57% of the blood drops tested positive for rno-mir-122-3p; however, other samples tested negative giving inconclusive results as to the wound-of-origin. The amount of the liver cells in the bloodstains appeared to be related to the extent of trauma. © 2017 American Academy of Forensic Sciences.

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

NASA Technical Reports Server (NTRS)

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

1976-01-01

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

Gravity-Dependent Combustion and Fluids Research - From Drop Towers to Aircraft to the ISS

NASA Technical Reports Server (NTRS)

Urban, David L.; Singh, Bhim S.; Kohl, Fred J.

2007-01-01

Driven by the need for knowledge related to the low-gravity environment behavior of fluids in liquid fuels management, thermal control systems and fire safety for spacecraft, NASA embarked on a decades long research program to understand, accommodate and utilize the relevant phenomena. Beginning in the 1950s, and continuing through to today, drop towers and aircraft were used to conduct an ever broadening and increasingly sophisticated suite of experiments designed to elucidate the underlying gravity-dependent physics that drive these processes. But the drop towers and aircraft afford only short time periods of continuous low gravity. Some of the earliest rocket test flights and manned space missions hosted longer duration experiments. The relatively longer duration low-g times available on the space shuttle during the 1980s and 1990s enabled many specialized experiments that provided unique data for a wide range of science and engineering disciplines. Indeed, a number of STS-based Spacelab missions were dedicated solely to basic and applied microgravity research in the biological, life and physical sciences. Between 1980 and 2000, NASA implemented a vigorous Microgravity Science Program wherein combustion science and fluid physics were major components. The current era of space stations from the MIR to the International Space Station have opened up a broad range of opportunities and facilities that are now available to support both applied research for technologies that will help to enable the future exploration missions and for a continuation of the non-exploration basic research that began over fifty years ago. The ISS-based facilities of particular value to the fluid physics and combustion/fire safety communities are the Fluids and Combustion Facility Combustion Integrated Rack and the Fluids Integrated Rack.

Football helmet drop tests on different fields using an instrumented Hybrid III head.

PubMed

Viano, David C; Withnall, Chris; Wonnacott, Michael

2012-01-01

An instrumented Hybrid III head was placed in a Schutt ION 4D football helmet and dropped on different turfs to study field types and temperature on head responses. The head was dropped 0.91 and 1.83 m giving impacts of 4.2 and 6.0 m/s on nine different football fields (natural, Astroplay, Fieldturf, or Gameday turfs) at turf temperatures of -2.7 to 23.9 °C. Six repeat tests were conducted for each surface at 0.3 m (1') intervals. The Hybrid III was instrumented with triaxial accelerometers to determine head responses for the different playing surfaces. For the 0.91-m drops, peak head acceleration varied from 63.3 to 117.1 g and HIC(15) from 195 to 478 with the different playing surfaces. The lowest response was with Astroplay, followed by the engineered natural turf. Gameday and Fieldturf involved higher responses. The differences between surfaces decreased in the 1.83 m tests. The cold weather testing involved higher accelerations, HIC(15) and delta V for each surface. The helmet drop test used in this study provides a simple and convenient means of evaluating the compliance and energy absorption of football playing surfaces. The type and temperature of the playing surface influence head responses.

Water Impact Test and Simulation of a Composite Energy Absorbing Fuselage Section

NASA Technical Reports Server (NTRS)

Fasanella, Edwin L.; Jackson, Karen E.; Sparks, Chad; Sareen, Ashish

2003-01-01

In March 2002, a 25-ft/s vertical drop test of a composite fuselage section was conducted onto water. The purpose of the test was to obtain experimental data characterizing the structural response of the fuselage section during water impact for comparison with two previous drop tests that were performed onto a rigid surface and soft soil. For the drop test, the fuselage section was configured with ten 100-lb. lead masses, five per side, that were attached to seat rails mounted to the floor. The fuselage section was raised to a height of 10-ft. and dropped vertically into a 15-ft. diameter pool filled to a depth of 3.5-ft. with water. Approximately 70 channels of data were collected during the drop test at a 10-kHz sampling rate. The test data were used to validate crash simulations of the water impact that were developed using the nonlinear, explicit transient dynamic codes, MSC.Dytran and LS-DYNA. The fuselage structure was modeled using shell and solid elements with a Lagrangian mesh, and the water was modeled with both Eulerian and Lagrangian techniques. The fluid-structure interactions were executed using the fast general coupling in MSC.Dytran and the Arbitrary Lagrange-Euler (ALE) coupling in LS-DYNA. Additionally, the smooth particle hydrodynamics (SPH) meshless Lagrangian technique was used in LS-DYNA to represent the fluid. The simulation results were correlated with the test data to validate the modeling approach. Additional simulation studies were performed to determine how changes in mesh density, mesh uniformity, fluid viscosity, and failure strain influence the test-analysis correlation.

Self-reported use of complementary and alternative medicine therapies in a reflexology randomized clinical trial.

PubMed

Wyatt, Gwen; Sikorskii, Alla; You, Mei

2013-01-01

According to the National Center for Complementary and Alternative Medicine (NCCAM), about one-third of American cancer patients have used complementary and alternative medicine (CAM). The objective of this secondary analysis was an assessment of the use of other CAM by women with advanced breast cancer who were undergoing chemotherapy and who participated in a randomized clinical trial (RCT) studying the safety and efficacy of reflexology. For this secondary analysis, the research team hypothesized an increased CAM use due to exposure to the reflexology trial. For this secondary analysis, the team conducted telephone interviews at baseline, wk 5, and wk 11 to assess the use of 23 common CAM therapies. The study took place at 14 medical oncology clinics across the Midwestern United States. Participants included women with advanced breast cancer who were undergoing chemotherapy and/or hormonal therapy. In the study related to this secondary analysis, the research team randomly assigned the women to one of three primary groups: (1) reflexology; (2) lay foot manipulation (LFM); and (3) control. In addition, the research team used two test groups to establish the study's protocol: (1) test reflexology and (2) test LFM. For this secondary analysis, the research team considered the two reflexology groups (test and intervention) and the two LFM groups (test and intervention) to be the active groups, comparing their use of CAM to the control group's use at the selected time points. The research team used a linear, mixed-effects model to analyze the number of therapies used at the three time points. The team performed t tests to compare therapy use at baseline for those women who completed the study vs those who dropped out. The team used the CAM-use instrument. In total, 385 women participated. The research team found no differences in CAM use for the active groups vs the control group over time or in those women who stayed in the study vs those who dropped out. The team found an increase in CAM use at wk 5 compared to baseline, followed by a decrease at wk 11; however, the time trends were the same in the active groups and the control group In women with advanced breast cancer, researchers can rely upon one assessment of CAM use during an RCT of a CAM therapy.

Usage of drip drops as stimuli in an auditory P300 BCI paradigm.

PubMed

Huang, Minqiang; Jin, Jing; Zhang, Yu; Hu, Dewen; Wang, Xingyu

2018-02-01

Recently, many auditory BCIs are using beeps as auditory stimuli, while beeps sound unnatural and unpleasant for some people. It is proved that natural sounds make people feel comfortable, decrease fatigue, and improve the performance of auditory BCI systems. Drip drop is a kind of natural sounds that makes humans feel relaxed and comfortable. In this work, three kinds of drip drops were used as stimuli in an auditory-based BCI system to improve the user-friendness of the system. This study explored whether drip drops could be used as stimuli in the auditory BCI system. The auditory BCI paradigm with drip-drop stimuli, which was called the drip-drop paradigm (DP), was compared with the auditory paradigm with beep stimuli, also known as the beep paradigm (BP), in items of event-related potential amplitudes, online accuracies and scores on the likability and difficulty to demonstrate the advantages of DP. DP obtained significantly higher online accuracy and information transfer rate than the BP ( p  < 0.05, Wilcoxon signed test; p  < 0.05, Wilcoxon signed test). Besides, DP obtained higher scores on the likability with no significant difference on the difficulty ( p  < 0.05, Wilcoxon signed test). The results showed that the drip drops were reliable acoustic materials as stimuli in an auditory BCI system.

Spacelab

NASA Image and Video Library

1992-06-01

The first United States Microgravity Laboratory (USML-1) was one of NASA's science and technology programs that provided scientists an opportunity to research various scientific investigations in a weightlessness environment inside the Spacelab module. It also provided demonstrations of new equipment to help prepare for advanced microgravity research and processing aboard the Space Station. The USML-1 flew in orbit for extended periods, providing greater opportunities for research in materials science, fluid dynamics, biotechnology (crystal growth), and combustion science. This is a close-up view of the Drop Physics Module (DPM) in the USML science laboratory. The DPM was dedicated to the detailed study of the dynamics of fluid drops in microgravity: their equilibrium shapes, the dynamics of their flows, and their stable and chaotic behaviors. It also demonstrated a technique known as containerless processing. The DPM and microgravity combine to remove the effects of the container, such as chemical contamination and shape, on the sample being studied. Sound waves, generating acoustic forces, were used to suspend a sample in microgravity and to hold a sample of free drops away from the walls of the experiment chamber, which isolated the sample from potentially harmful external influences. The DPM gave scientists the opportunity to test theories of classical fluid physics, which have not been confirmed by experiments conducted on Earth. This image is a close-up view of the DPM. The USML-1 flew aboard the STS-50 mission on June 1992, and was managed by the Marshall Space Flight Center.

Test pilots 1962 - Armstrong, Walker, Dana, Peterson, McKay, Thompson, Butchart

NASA Technical Reports Server (NTRS)

1962-01-01

The research pilots at what in 1962 was called the Flight Research Center standing in front of the X-1E. They are (left to right) Neil Armstrong, Joe Walker, Bill Dana, Bruce Peterson, Jack McKay, Milt Thompson, and Stan Butchart. of the group, Armstrong, Walker, Dana, McKay and Thompson all flew the X-15. Bruce Peterson flew the M2-F2 and HL-10 lifting bodies, while Stan Butchart was the B-29 drop plane pilot for many of the D-558-II and X-1 series research aircraft.

Standardized Sample Preparation Using a Drop-on-Demand Printing Platform

DTIC Science & Technology

2013-05-07

successful and robust methodology for energetic sample preparation. Keywords: drop-on-demand; inkjet printing; sample preparation OPEN ACCESS...on a similar length scale. Recently, drop-on-demand inkjet printing technology has emerged as an effective approach to produce test materials to...which most of the material is concentrated along the edges, samples prepared using drop-on-demand inkjet technology demonstrate excellent uniform

Vertical Drop Testing and Analysis of the WASP Helicopter Skid Gear

NASA Technical Reports Server (NTRS)

Fuchs, Yvonne T.; Jackson, Karen E.

2008-01-01

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

Vertical Drop Testing and Analysis of the WASP Helicopter Skid Gear

NASA Technical Reports Server (NTRS)

Fuchs, Yvonne T.; Jackson, Karen E.

2008-01-01

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

14 CFR 23.725 - Limit drop tests.

Code of Federal Regulations, 2011 CFR

2011-01-01

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

14 CFR 23.725 - Limit drop tests.

Code of Federal Regulations, 2013 CFR

2013-01-01

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

14 CFR 23.725 - Limit drop tests.

Code of Federal Regulations, 2012 CFR

2012-01-01

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

14 CFR 23.725 - Limit drop tests.

Code of Federal Regulations, 2014 CFR

2014-01-01

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

Student Drop Tower Competitions: Dropping In a Microgravity Environment (DIME) and What If No Gravity? (WING)

NASA Technical Reports Server (NTRS)

Hall, Nancy R.; Stocker, Dennis P.; DeLombard, Richard

2011-01-01

This paper describes two student competition programs that allow student teams to conceive a science or engineering experiment for a microgravity environment. Selected teams design and build their experimental hardware, conduct baseline tests, and ship their experiment to NASA where it is operated in the 2.2 Second Drop Tower. The hardware and acquired data is provided to the teams after the tests are conducted so that the teams can prepare their final reports about their findings.

Research on metal solidification in zero-g state

NASA Technical Reports Server (NTRS)

Papazian, J. M.; Larson, D. J., Jr.

1975-01-01

The containerless solidification of several pure metals and metallic alloys was studied in a low gravity environment. The tests were performed in the MSFC 4.2 s drop tower using a rapid wire melting apparatus designed and built for this purpose. Pure iron and nickel, and alloys of iron-nickel, iron-carbon, nickel-aluminum and tungsten-rhenium were all melted and solidified at a gravity level of approximately 100.000/-4 g. Interpretation of the results has led to an appreciation of the factors controlling the successful execution of this drop test experiment and to a delineation of the limits of applicability of the apparatus. Preliminary metallurgical evaluations are presented of the overall shapes, lattice parameters, surface microstructure,, cross-sectional microstructures, solidification and transformation sequences, evaporative segregation, and localized solute redistribution observed in the low-gravity specimens. The effects of low gravity on metallic solidification are discussed with particular emphasis on observations of spontaneous undercooling and evaporative segregation in uncontained melts.

Creating a Bimodal Drop-Size Distribution in the NASA Glenn Icing Research Tunnel

NASA Technical Reports Server (NTRS)

King-Steen, Laura E.; Ide, Robert F.

2017-01-01

The Icing Research Tunnel at NASA Glenn has demonstrated that they can create a drop-size distribution that matches the FAA Part 25 Appendix O FZDZ, MVD <40 microns normalized cumulative volume within 10%. This is done by simultaneously spraying the Standard and Mod1 nozzles at the same nozzle air pressure and different nozzle water pressures. It was also found through these tests that the distributions that are measured when the two nozzle sets are sprayed simultaneously closely matched what was found by combining the two individual distributions analytically. Additionally, distributions were compared between spraying all spraybars and also by spraying only every-other spraybar, and were found to match within 4%. The cloud liquid water content uniformity for this condition has been found to be excellent. It should be noted, however, that the liquid water content for this condition in the IRT is much higher than the requirement specified in Part 25 Appendix O.

Creating a Bimodal Drop-Size Distribution in the NASA Glenn Icing Research Tunnel

NASA Technical Reports Server (NTRS)

King-Steen, Laura E.; Ide, Robert F.

2017-01-01

The Icing Research Tunnel at NASA Glenn has demonstrated that they can create a drop-size distribution that matches the FAA Part 25 Appendix O FZDZ, MVD40 m normalized cumulative volume within 10. This is done by simultaneously spraying the Standard and Mod1 nozzles at the same nozzle air pressure and different nozzle water pressures. It was also found through these tests that the distributions that are measured when the two nozzle sets are sprayed simultaneously closely matched what was found by combining the two individual distributions analytically. Additionally, distributions were compared between spraying all spraybars and also by spraying only every-other spraybar, and were found to match within 4. The cloud liquid water content uniformity for this condition has been found to be excellent: 10. It should be noted, however, that the liquid water content for this condition in the IRT is much higher than the requirement specified in Part 25 Appendix O.

Effect of Electromigration on the Type of Drop Failure of Sn-3.0Ag-0.5Cu Solder Joints in PBGA Packages

NASA Astrophysics Data System (ADS)

Huang, M. L.; Zhao, N.

2015-10-01

Board-level drop tests of plastic ball grid array (PBGA) packages were performed in accordance with the Joint Electron Devices Engineering Council standard to investigate the effect of electromigration (EM) on the drop reliability of Sn-3.0Ag-0.5Cu solder joints with two substrate surface finishes, organic solderability preservative (OSP) and electroless nickel electroless palladium immersion gold (ENEPIG). In the as-soldered state, drop failures occurred at the substrate sides only, with cracks propagating within the interfacial intermetallic compound (IMC) layer for OSP solder joints and along the IMC/Ni-P interface for ENEPIG solder joints. The drop lifetime of OSP solder joints was approximately twice that of ENEPIG joints. EM had an important effect on crack formation and drop lifetime of the PBGA solder joints. ENEPIG solder joints performed better in drop reliability tests after EM, that is, the drop lifetime of ENEPIG joints decreased by 43% whereas that of OSP solder joints decreased by 91%, compared with the as-soldered cases. The more serious polarity effect, i.e., excessive growth of the interfacial IMC at the anode, was responsible for the sharper decrease in drop lifetime. The different types of drop failure of PBGA solder joints before and after EM, including the position of initiation and the propagation path of cracks, are discussed on the basis of the growth behavior of interfacial IMC.

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

NASA Astrophysics Data System (ADS)

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

2009-03-01

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

Water intake and post-exercise cognitive performance: an observational study of long-distance walkers and runners.

PubMed

Benefer, Martin D; Corfe, Bernard M; Russell, Jean M; Short, Richard; Barker, Margo E

2013-03-01

The impact of diet on endurance performance and cognitive function has been extensively researched in controlled settings, but there are limited observational data in field situations. This study examines relationships between nutrient intake and cognitive function following endurance exercise amongst a group of 33 recreational runners and walkers. All participants (mean age of 43.2 years) took part in a long-distance walking event and completed diet diaries to estimate nutrient intake across three-time periods (previous day, breakfast and during the event). Anthropometric measurements were recorded. Cognitive tests, covering word recall, ruler drop and trail making tests (TMT) A and B were conducted pre- and post-exercise. Participants rated their exercise level on a validated scale. Nutrient intake data were summarised using principal components analysis to identify a nutrient intake pattern loaded towards water intake across all time periods. Regression analysis was used to ascertain relationships between water intake component scores and post-exercise cognitive function, controlling for anthropometric measures and exercise metrics (distance, duration and pace). Participants rated their exercise as 'hard-heavy' (score 14.4, ±3.2). Scores on the water intake factor were associated with significantly faster TMT A (p = 0.001) and TMT B (p = 0.005) completion times, and a tendency for improved short-term memory (p = 0.090). Water intake scores were not associated with simple reaction time (assessed via the ruler drop test). These data are congruent with experimental research demonstrating a benefit of hydration on cognitive function. Further field research to confirm this relationship, supported with precise measures of body weight, is needed.

Dynamic in-vivo assessment of navicular drop while running in barefoot, minimalist, and motion control footwear conditions.

PubMed

Hoffman, Scott E; Peltz, Cathryn D; Haladik, Jeffrey A; Divine, George; Nurse, Matthew A; Bey, Michael J

2015-03-01

Running-related injuries are common and previous research has suggested that the magnitude and/or rate of pronation may contribute to the development of these injuries. Accurately and directly measuring pronation can be challenging, and therefore previous research has often relied on navicular drop (under both static and dynamic conditions) as an indirect assessment of pronation. The objectives of this study were to use dynamic, biplane X-ray imaging to assess the effects of three footwear conditions (barefoot, minimalist shoes, motion control shoes) on the magnitude and rate of navicular drop during running, and to determine the association between static and dynamic measures of navicular drop. Twelve healthy distance runners participated in this study. The magnitude and rate of navicular drop were determined by tracking the 3D position of the navicular from biplane radiographic images acquired at 60Hz during the stance phase of overground running. Static assessments of navicular drop and foot posture were also recorded in each subject. Footwear condition was not found to have a significant effect on the magnitude of navicular drop (p=0.22), but motion control shoes had a slower navicular drop rate than running barefoot (p=0.05) or in minimalist shoes (p=0.05). In an exploratory analysis, static assessments of navicular drop and foot posture were found to be poor predictors of dynamic navicular drop in all footwear conditions (p>0.18). Copyright © 2015 Elsevier B.V. All rights reserved.

If you provide the test, they will take it: factors associated with HIV/STI Testing in a representative sample of homeless youth in Los Angeles.

PubMed

Ober, Allison J; Martino, Steven C; Ewing, Brett; Tucker, Joan S

2012-08-01

Homeless youth are at high risk for human immunodeficiency virus (HIV) and other sexually transmitted infections (STI), yet those at greatest risk may never have been tested for HIV or STI. In a probability sample of sexually active homeless youth in Los Angeles (n = 305), this study identifies factors associated with HIV/STI testing status. Most youth (85%) had ever been tested and 47% had been tested in the past 3 months. Recent testing was significantly more likely among youth who self-identified as gay, were Hispanic, injected drugs, and used drop-in centers, and marginally more likely among youth with more depressive symptoms. Drop-in center use mediated the association of injection drug use with HIV/STI testing. HIV/STI testing was unrelated to sexual risk behavior. Drop-in centers can play an important role in facilitating testing, including among injection drug users, but more outreach is needed to encourage testing in other at-risk subgroups.

If You Provide the Test, They will Take It: Factors Associated with HIV/STI Testing in a Representative Sample of Homeless Youth in Los Angeles*

PubMed Central

Ober, Allison J.; Martino, Steven C.; Ewing, Brett; Tucker, Joan S.

2012-01-01

Homeless youth are at high risk for human immunodeficiency virus (HIV) and other sexually transmitted infections (STI), yet those at greatest risk may never have been tested for HIV or STI. In a probability sample of sexually active homeless youth in Los Angeles (n =305), this study identifies factors associated with HIV/STI testing status. Most youth (85%) had ever been tested and 47% had tested in the past 3 months. Recent testing was significantly more likely among youth who self-identified as gay, were Hispanic, injected drugs, and used drop-in centers, and marginally more likely among youth with more depressive symptoms. Drop-in center use mediated the association of injection drug use with HIV/STI testing. HIV/STI testing was unrelated to sexual risk behavior. Drop-in centers can play an important role in facilitating testing, including among injection drug users, but more outreach is needed to encourage testing in other at-risk subgroups. PMID:22827904

Development of a primary standard for dynamic pressure based on drop weight method covering a range of 10 MPa-400 MPa

NASA Astrophysics Data System (ADS)

Salminen, J.; Högström, R.; Saxholm, S.; Lakka, A.; Riski, K.; Heinonen, M.

2018-04-01

In this paper we present the development of a primary standard for dynamic pressures that is based on the drop weight method. At the moment dynamic pressure transducers are typically calibrated using reference transducers, which are calibrated against static pressure standards. Because dynamic and static characteristics of pressure transducers may significantly differ from each other, it is important that these transducers are calibrated against dynamic pressure standards. In a method developed in VTT Technical Research Centre of Finland Ltd, Centre for Metrology MIKES, a pressure pulse is generated by impact between a dropping weight and a piston of a liquid-filled piston-cylinder assembly. The traceability to SI-units is realized through interferometric measurement of the acceleration of the dropping weight during impact, the effective area of the piston-cylinder assembly and the mass of the weight. Based on experimental validation and an uncertainty evaluation, the developed primary standard provides traceability for peak pressures in the range from 10 MPa to 400 MPa with a few millisecond pulse width and a typical relative expanded uncertainty (k  =  2) of 1.5%. The performance of the primary standard is demonstrated by test calibrations of two dynamic pressure transducers.

Scanning drop sensor

DOEpatents

Jin, Jian; Xiang, Chengxiang; Gregoire, John

2017-05-09

Electrochemical experiments are performed on a collection of samples by suspending a drop of electrolyte solution between an electrochemical experiment probe and one of the samples that serves as a test sample. During the electrochemical experiment, the electrolyte solution is added to the drop and an output solution is removed from the drop. The probe and collection of samples can be moved relative to one another so the probe can be scanned across the samples.

Surface tension propellant control for Viking 75 Orbiter

NASA Technical Reports Server (NTRS)

Dowdy, M. W.; Hise, R. E.; Peterson, R. G.; Debrock, S. C.

1976-01-01

The paper describes the selection, development and qualification of the surface tension system and includes results of low-g drop tower tests of scale models, 1-g simulation tests of low-g large ullage settling and liquid withdrawal, structural qualification tests, and propellant surface tension/contact angle studies. Subscale testing and analyses were used to evaluate the ability of the system to maintain or recover the desired propellant orientation following possible disturbances during the Viking mission. This effort included drop tower tests to demonstrate that valid wick paths exist for moving any displaced propellant back over the tank outlet. Variations in surface tension resulting from aging, temperature, and lubricant contamination were studied and the effects of surface finish, referee fluid exposure, aging, and lubricant contamination on contact angle were assessed. Results of movies of typical subscale drop tower tests and full scale slosh tests are discussed.

A novel generation of 3D SAR-based passive micromixer: efficient mixing and low pressure drop at a low Reynolds number

NASA Astrophysics Data System (ADS)

Viktorov, Vladimir; Nimafar, Mohammad

2013-05-01

This study introduces a novel generation of 3D splitting and recombination (SAR) passive micromixer with microstructures placed on the top and bottom floors of microchannels called a ‘chain mixer’. Both experimental verification and numerical analysis of the flow structure of this type of passive micromixer have been performed to evaluate the mixing performance and pressure drop of the microchannel, respectively. We propose here two types of chain mixer—chain 1 and chain 2—and compare their mixing performance and pressure drop with other micromixers, T-, o- and tear-drop micromixers. Experimental tests carried out in the laminar flow regime with a low Reynolds number range, 0.083 ≤ Re ≤ 4.166, and image-based techniques are used to evaluate the mixing efficiency. Also, the computational fluid dynamics code, ANSYS FLUENT-13.0 has been used to analyze the flow and pressure drop in the microchannel. Experimental results show that the chain and tear-drop mixer's efficiency is very high because of the SAR process: specifically, an efficiency of up to 98% can be achieved at the tested Reynolds number. The results also show that chain mixers have a lower required pressure drop in comparison with a tear-drop micromixer.

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

NASA Technical Reports Server (NTRS)

Quade, D. A.

1978-01-01

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

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

PubMed

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

2016-05-01

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

"Open mesh" or "strictly selected population" recruitment? The experience of the randomized controlled MeMeMe trial.

PubMed

Cortellini, Mauro; Berrino, Franco; Pasanisi, Patrizia

2017-01-01

Among randomized controlled trials (RCTs), trials for primary prevention require large samples and long follow-up to obtain a high-quality outcome; therefore the recruitment process and the drop-out rates largely dictate the adequacy of the results. We are conducting a Phase III trial on persons with metabolic syndrome to test the hypothesis that comprehensive lifestyle changes and/or metformin treatment prevents age-related chronic diseases (the MeMeMe trial, EudraCT number: 2012-005427-32, also registered on ClinicalTrials.gov [NCT02960711]). Here, we briefly analyze and discuss the reasons which may lead to participants dropping out from trials. In our experience, participants may back out of a trial for different reasons. Drug-induced side effects are certainly the most compelling reason. But what are the other reasons, relating to the participants' perception of the progress of the trial which led them to withdraw after randomization? What about the time-dependent drop-out rate in primary prevention trials? The primary outcome of this analysis is the point of drop-out from trial, defined as the time from the randomization date to the withdrawal date. Survival functions were non-parametrically estimated using the product-limit estimator. The curves were statistically compared using the log-rank test ( P =0.64, not significant). Researchers involved in primary prevention RCTs seem to have to deal with the paradox of the proverbial "short blanket syndrome". Recruiting only highly motivated candidates might be useful for the smooth progress of the trial but it may lead to a very low enrollment rate. On the other hand, what about enrolling all the eligible subjects without considering their motivation? This might boost the enrollment rate, but it can lead to biased results on account of large proportions of drop-outs. Our experience suggests that participants do not change their mind depending on the allocation group (intervention or control). There is no single answer to sort out the short blanket syndrome.

[Optimize dropping process of Ginkgo biloba dropping pills by using design space approach].

PubMed

Shen, Ji-Chen; Wang, Qing-Qing; Chen, An; Pan, Fang-Lai; Gong, Xing-Chu; Qu, Hai-Bin

2017-07-01

In this paper, a design space approach was applied to optimize the dropping process of Ginkgo biloba dropping pills. Firstly, potential critical process parameters and potential process critical quality attributes were determined through literature research and pre-experiments. Secondly, experiments were carried out according to Box-Behnken design. Then the critical process parameters and critical quality attributes were determined based on the experimental results. Thirdly, second-order polynomial models were used to describe the quantitative relationships between critical process parameters and critical quality attributes. Finally, a probability-based design space was calculated and verified. The verification results showed that efficient production of Ginkgo biloba dropping pills can be guaranteed by operating within the design space parameters. The recommended operation ranges for the critical dropping process parameters of Ginkgo biloba dropping pills were as follows: dropping distance of 5.5-6.7 cm, and dropping speed of 59-60 drops per minute, providing a reference for industrial production of Ginkgo biloba dropping pills. Copyright© by the Chinese Pharmaceutical Association.

Spray Drift Reduction Evaluations of Spray Nozzles Using a Standardized Testing Protocol

DTIC Science & Technology

2010-07-01

Drop Size Characteristics in a Spray Using Optical Nonimaging Light-Scattering Instruments,” Annual Book of ASTM Standards, Vol. 14-02, ASTM...Test Method for Determining Liquid Drop Size Characteristics in a Spray Using Optical Non- imaging Light-Scattering Instruments 22. AGDISP Model

49 CFR 178.810 - Drop test.

Code of Federal Regulations, 2010 CFR

2010-10-01

... preparation for the drop test. (1) Metal, rigid plastic, and composite IBCs intended to contain solids must be.... (4) Rigid plastic IBCs and composite IBCs with plastic inner receptacles must be conditioned for... material having essentially the same physical characteristics. (3) The specific gravity and viscosity of a...

Experimental Methods Using Photogrammetric Techniques for Parachute Canopy Shape Measurements

NASA Technical Reports Server (NTRS)

Jones, Thomas W.; Downey, James M.; Lunsford, Charles B.; Desabrais, Kenneth J.; Noetscher, Gregory

2007-01-01

NASA Langley Research Center in partnership with the U.S. Army Natick Soldier Center has collaborated on the development of a payload instrumentation package to record the physical parameters observed during parachute air drop tests. The instrumentation package records a variety of parameters including canopy shape, suspension line loads, payload 3-axis acceleration, and payload velocity. This report discusses the instrumentation design and development process, as well as the photogrammetric measurement technique used to provide shape measurements. The scaled model tests were conducted in the NASA Glenn Plum Brook Space Propulsion Facility, OH.

Consistency of field dependence in treated alcoholics.

PubMed

Danahy, S; Kahn, M W

1981-10-01

In accounting for the consistent finding that alcoholics are more field dependent than other groups, research generally supports the predisposition rather than the consequence hypothesis. In this study 32 alcoholics were tested for field dependence with Embedded Figures on admission to and at discharge from a 60-d treatment program. A large and significant drop in the field dependence measure was found, supporting the consequence hypothesis. The pre-posttime period not controlled in other studies, allowing for clearing acute effects and improved nutrition, health, and test motivation, amy account for this change.

The X-38 vehicle #131R arrives at NASA Dryden Flight Research Center

NASA Image and Video Library

2000-07-11

The X-38 Vehicle 131R, intended to prove the utility of a "lifeboat" crew return vehicle to bring crews home from the International Space Station in the event of an emergency, was unloaded from NASA's Super Guppy transport aircraft on July 11, 2000. The newest X-38 version arrived at Dryden for drop tests from NASA's venerable B-52 mother ship. The tests will evaluate a 7,500 square-foot parafoil intended to permit the CRV to return from space and land in the length of a football field.

The X-38 vehicle #131R arrives at NASA Dryden Flight Research Center

NASA Technical Reports Server (NTRS)

2000-01-01

The X-38 Vehicle 131R, intended to prove the utility of a 'lifeboat' crew return vehicle to bring crews home from the International Space Station in the event of an emergency, was unloaded from NASA's Super Guppy transport aircraft on July 11, 2000. The newest X-38 version arrived at Dryden for drop tests from NASA's venerable B-52 mother ship. The tests will evaluate a 7,500 square-foot parafoil intended to permit the CRV to return from space and land in the length of a football field.

Analysis and Evaluation of German Attainments and Research in the Liquid Rocket Engine Field. Volume 4. Propellant Injectors

DTIC Science & Technology

1951-02-01

they were ob- served at a given pressure drop in "cold" testing with water or unreacted propellants. heat-transfer considerations and the location of... water as a coolant in the main chamber. The Winkler injector was used.on a test unit developing a thrust of 220 lb and an exhaust ve- locity of 6370 ft... water . Provision was made for an igniter in the center of the injector. The relatively high performance reported for this unit does not seem to be

Instrument Development of Real Time Holographic Water Drop Size Measurement System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Springston, Stephen

2007-02-09

BNL participated with multiple correspondences with Physical Optics Corporation (POC) on the design considerations of an airbome instrument. A pod for extemal deployment ofthe POC unit on the DOE Research Aircraft Facility (RAF), an instrumented, Grumman G-1 aircraft was loaned to POC. BNL proposed evaluation flight tests between the POC unit and the BNL Cloud Aerosol Probe Spectrometer (CAPS) as a reference method. BNL's involvement is described in the semi-annual report ofPOC to DOE. Because of unanticipated technical and engineering difficulties, POC was unable to fit their instrument into an aircraft pod. As a result they are now focusing onmore » a ground-based version first. A prototype laboratory version of the Real-Time Holographic Water Drop Size Measurement (WDSM) System has been constructed.« less

Method of evaluation of process of red blood cell sedimentation based on photometry of droplet samples.

PubMed

Aristov, Alexander; Nosova, Ekaterina

2017-04-01

The paper focuses on research aimed at creating and testing a new approach to evaluate the processes of aggregation and sedimentation of red blood cells for purpose of its use in clinical laboratory diagnostics. The proposed method is based on photometric analysis of blood sample formed as a sessile drop. The results of clinical approbation of this method are given in the paper. Analysis of the processes occurring in the sample in the form of sessile drop during the process of blood cells sedimentation is described. The results of experimental studies to evaluate the effect of the droplet sample focusing properties on light radiation transmittance are presented. It is shown that this method significantly reduces the sample volume and provides sufficiently high sensitivity to the studied processes.

Experimental and numerical study of drill bit drop tests on Kuru granite

NASA Astrophysics Data System (ADS)

Fourmeau, Marion; Kane, Alexandre; Hokka, Mikko

2017-01-01

This paper presents an experimental and numerical study of Kuru grey granite impacted with a seven-buttons drill bit mounted on an instrumented drop test machine. The force versus displacement curves during the impact, so-called bit-rock interaction (BRI) curves, were obtained using strain gauge measurements for two levels of impact energy. Moreover, the volume of removed rock after each drop test was evaluated by stereo-lithography (three-dimensional surface reconstruction). A modified version of the Holmquist-Johnson-Cook (MHJC) material model was calibrated using Kuru granite test results available from the literature. Numerical simulations of the single drop tests were carried out using the MHJC model available in the LS-DYNA explicit finite-element solver. The influence of the impact energy and additional confining pressure on the BRI curves and the volume of the removed rock is discussed. In addition, the influence of the rock surface shape before impact was evaluated using two different mesh geometries: a flat surface and a hyperbolic surface. The experimental and numerical results are compared and discussed in terms of drilling efficiency through the mechanical specific energy. This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'.

Effect of External Pressure Drop on Loop Heat Pipe Operating Temperature

NASA Technical Reports Server (NTRS)

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

2002-01-01

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

[Stability of physical state on compound hawthorn dropping pills].

PubMed

Zhang, Wei; Chen, Hong-Yan; Jiang, Jian-Lan

2008-11-01

To evaluate the stability of physical state with accelerate test and dropping in process before and after on compound hawthorn dropping pills. Scanning electron microscope, TG-DTA, FT-IR and XRD were used. The active components presented amorphous, tiny crystal and molecular state in dropping pills, and it had no obvious reaction between PEG 4000 and active components. With time prolonging, a little of active components changed from amorphous state to tiny crystal or molecular state. Solid dispersion improved the stability and dissolution of compound hawthorn dropping pills.

Predictions of Helmet Pad Suspension System Performance using Isolated Pad Impact Results

DTIC Science & Technology

2010-09-13

Equation 2 and Equation 3, respectively. 3. METHOD The primary method of data collection for this report is detailed in the 2008 Joint Live Fire ...tests and the helmet system tests (see Figure 3). All testing was performed with a monorail drop tower (see Figure 4) at three conditioning...right) and system test setup (right and center left) Figure 5. MEP monorail drop test setup with a hemispherical impactor (left and center left

Modeling of drop breakup in the bag breakup regime

NASA Astrophysics Data System (ADS)

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

2014-04-01

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

Propelling a water drop with the vapor-mediated Marangoni effect

NASA Astrophysics Data System (ADS)

Kim, Seungho; Kim, Ho-Young

2013-11-01

We show that a water drop on solid surfaces can be propelled just by placing a volatile alcohol drop nearby. It is found to be because the water-air interface near the alcohol drop mixes with alcohol vapor, thereby locally lowering the surface tension. The surface-tension-gradient induces the motion of the water drop, enabling the trajectory control of water drops through the motion of remote alcohol drops. This vapor-mediated Marangoni effect also gives rise to other interesting interfacial flow phenomena, such as nucleation of holes on a water film and ballooning of a water drop hanging from a syringe needle with the approach of an alcohol drop. We visualize such interfacial dynamics with a high-speed camera and rationalize their salient features by scaling analysis. This work was supported by the National Research Foundation of Korea (grant no. 2012-008023).

Emergency Locator Transmitter Crash Testing

NASA Image and Video Library

2015-07-29

Drop-testing a series of three Cessna 172 aircraft, NASA simulated severe but survivable plane accidents on July 2, July 29 and August 26, 2015, to test emergency locator transmitters (ELTs). A research team equipped the vintage airplanes with five ELTs, two crash test dummies, cameras and data-collecting sensors. ELTs are installed on general aviation and commercial planes to transmit a location signal in the event of a crash. Current ELT models send that signal to orbiting satellites, which repeat it to the nearest search and rescue ground station. The signal is used to determine and transmit the ELT's identity and location to rescuers. ELTs have to work in the extreme circumstances involved in an airplane crash. Included in those extreme circumstances are the possibilities of excessive vibration, fire and impact damage. NASA research is designed to find practical ways to improve ELT system performance and robustness, giving rescue workers the best chance of saving lives. The research was funded by the Search and Rescue Mission Office at NASA's Goddard Space Flight Center in Greenbelt, Maryland. The testing took place at NASA’s Langley Research Center in Hampton, Virginia. This is a video of the July 29, 2015, test.

14 CFR 29.725 - Limit drop test.

Code of Federal Regulations, 2012 CFR

2012-01-01

... energy absorbing devices or by the use of an effective mass. (c) Each landing gear unit must be tested in the attitude simulating the landing condition that is most critical from the standpoint of the energy...-up attitude considered in the nose-up landing conditions. h=specified free drop height (inches). L...

14 CFR 29.725 - Limit drop test.

Code of Federal Regulations, 2014 CFR

2014-01-01

... energy absorbing devices or by the use of an effective mass. (c) Each landing gear unit must be tested in the attitude simulating the landing condition that is most critical from the standpoint of the energy...-up attitude considered in the nose-up landing conditions. h=specified free drop height (inches). L...

Evaluation of a Proposed Drift Reduction Technology High-Speed Wind Tunnel Testing Protocol

DTIC Science & Technology

2009-03-01

05: “Standard Test Method for Determining Liquid Drop Size Characteristics in a Spray Using Optical Nonimaging Light- Scattering Instruments” 15...Method for Determining Liquid Drop Size Characteris- tics in a Spray Using Optical Nonimaging Light-Scattering Instruments,” Annual Book of ASTM Standards

Scanning drop sensor

DOEpatents

Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Shinde, Aniketa A.; Guevarra, Dan W.; Jones, Ryan J.; Marcin, Martin R.; Mitrovic, Slobodan

2017-05-09

Electrochemical or electrochemical and photochemical experiments are performed on a collection of samples by suspending a drop of electrolyte solution between an electrochemical experiment probe and one of the samples that serves as a test sample. During the electrochemical experiment, the electrolyte solution is added to the drop and an output solution is removed from the drop. The probe and collection of samples can be moved relative to one another so the probe can be scanned across the samples.

Aviation Gas Turbine Engine Emissions: Drop in Alternative Fuel and its Challenges

NASA Astrophysics Data System (ADS)

Noh, H. Mohd; Rodrigo, G. A.; Rahman, N. A. Abdul; Ismail, S.; Shafie, M. A.; Zainal Ariffin, M. W.; Ahmad, A. A.; Basit, R.; Khalid, A.; Yahaya, N. H. R.; Yusoff, M. R.; Othman, J.

2018-05-01

The growing demand of air travel in aviation industries contributes to increases in carbon emissions. As far as technological, infrastructure and operation is concerned, carbon-neutral growth (CNG) cannot be achieved due to fossil fuel usage. The involvement of biojet fuel is the only measures that can be adapted to reduce up to -50% of Carbon emissions. This paper will discuss the gas emissions from the aircraft engine and the challenges it poses to Airlines and operation as well as adapting the Alternative drop-in fuel as its solutions. Alternative fuel using biomass has been approved by American Society for Testing and Materials (ASTM) to be a drop-in fuel with no alteration on the gas turbine engine, hence will ease and generate cost saving for the Airlines. The challenges remain, as the concern on the fuel properties and characteristics, distributions, environment and economic, have been the focal point for policymakers and researchers. As a conclusion, the authority and the government need to join hand in creating the opportunity for alternative fuel in the aviation industries to ensure the reduction in aviation carbon emissions.

Laboratory modeling of energy dissipation in broken-back culverts - phase II.

DOT National Transportation Integrated Search

2011-05-01

This report represents Phase II of broken-back culverts with a drop of 6 feet. The first phase of this research was performed for a drop of 24 feet. This research investigates the reduction in scour downstream of a broken-back culvert by forming a hy...

An Analytic Tool to Investigate the Effect of Binder on the Sensitivity of HMX-Based Plastic Bonded Explosives in the Skid Test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayden, D. W.

This project will develop an analytical tool to calculate performance of HMX based PBXs in the skid test. The skid-test is used as a means to measure sensitivity for large charges in handling situations. Each series of skid tests requires dozens of drops of large billets. It is proposed that the reaction (or lack of one) of PBXs in the skid test is governed by the mechanical properties of the binder. If true, one might be able to develop an analytical tool to estimate skid test behavior for new PBX formulations. Others over the past 50 years have tried tomore » develop similar models. This project will research and summarize the works of others and couple the work of 3 into an analytical tool that can be run on a PC to calculate drop height of HMX based PBXs. Detonation due to dropping a billet is argued to be a dynamic thermal event. To avoid detonation, the heat created due to friction at impact, must be conducted into the charge or the target faster than the chemical kinetics can create additional energy. The methodology will involve numerically solving the Frank-Kamenetskii equation in one dimension. The analytical problem needs to be bounded in terms of how much heat is introduced to the billet and for how long. Assuming an inelastic collision with no rebound, the billet will be in contact with the target for a short duration determined by the equations of motion. For the purposes of the calculations, it will be assumed that if a detonation is to occur, it will transpire within that time. The surface temperature will be raised according to the friction created using the equations of motion of dropping the billet on a rigid surface. The study will connect the works of Charles Anderson, Alan Randolph, Larry Hatler, Alfonse Popolato, and Charles Mader into a single PC based analytic tool. Anderson's equations of motion will be used to calculate the temperature rise upon impact, the time this temperature is maintained (contact time) will be obtained from the work of Hatler et. al., and the reactive temperature rise will be obtained from Mader's work. Finally, the assessment of when a detonation occurs will be derived from Bowden and Yoffe's thermal explosion theory (hot spot).« less

Comparative evaluation of Nano-Hydroxyapatite preparation and Calcium Sucrose Phosphate on microhardness of deciduous teeth after iron drop exposure - An in-vitro study.

PubMed

Rathi, Nilesh; Baid, Rutika; Baliga, Sudhindra; Thosar, Nilima

2017-04-01

To evaluate and compare the microhardness of deciduous teeth treated with nano-hydroxyapatite and calcium sucrose phosphate after iron drop exposure. Twenty healthy anterior deciduous teeth were collected and stored in 0.9% saline solution at room temperature. All the teeth were immersed in artificial saliva in an incubator shaker at 37° for an hour and then subjected to Vickers microhardness test at 100g load for 5 seconds. The teeth were then immersed in iron drop for 5 minutes, twice daily, rinsed with distilled water and kept in artificial saliva. This procedure was repeated for 7 days and teeth were subjected to microhardness testing. Further, the teeth were divided in two groups, each group containing 10 teeth. In group I, nanohydroxyapatite preparation and in group II, calcium sucrose phosphate were applied for 10 minutes, twice daily for 7 days and subjected again to microhardness testing again. Vickers microhardness analysis revealed that iron drop exposure to teeth caused significant decrease in microhardness ( p <0.05). Application of nanohydroxyapatite preparation in Group I showed significantly increased enamel microhardness (206.90) than that after iron drop exposure. Similarly, application of calcium sucrose phosphate in Group II showed significantly increased enamel microhardness (200.89) than that after iron drop exposure. Statistical difference was seen between the two groups, with nanohydroxyapatite preparation showing increased microhardness than calcium sucrose phosphate. Nanohydroxyapatite preparation and calcium sucrose phosphate have remineralizing effect over teeth affected by acid challenge of iron drops, nanohydroxyapatite preparation showing better results than calcium sucrose phosphate. Key words: Iron drops, Nanohydroxyapaptite, calcium sucrose phosphate, anticay.

Do dietetic patients in a regional area attend a drop-in diabetes outpatient clinic? Proof-of-concept observational study.

PubMed

Byrne, Clare; Roth, Rachel; Donnelly, Julianne; Dicker, Gill; Palmer, Michelle

2018-06-01

Drop-in clinics may be an alternative patient-centred approach to traditional appointment systems. However patient uptake in Allied Health settings is unknown. Given the limited literature, this observational prospective project tested whether patients with diabetes would present to a drop-in clinic, and whether the types and volume of patients would change due to introduction of a drop-in clinic. Alongside a referral-based booked individual appointment service (standard care (SC)), a drop-in clinic was introduced allowing patients to present without appointment. Patient data was collected from medical chart and outpatient appointment systems over 30 months. High category patient criteria included HbA1c>7.5%. Data was compared between drop-in and SC groups using chi-squared and ANOVA tests. Of 150 eligible patients, more drop-in patients (n = 76) presented over 15 months than SC patients booked in the 15 months before (n = 41) or 15 months after (n = 33) the drop-in clinic commenced. Drop-ins were 12 years older and less likely to have Type 1 Diabetes Mellitus (T1DM) than SC patients (p < 0.001), however the proportion of high category patients was similar across groups (54%, p = 0.731). SC patients were similar before and after drop-in clinic commencement (51%F, baseline HbA1c 9.5% ± 2.2, 34% clinic non-attendance, P = 0.159-0.671). Patients attended a drop-in diabetes outpatient clinic. This included high category patients. The weekday drop-in service may appeal to older patients with Type 2 Diabetes Mellitus, but not to younger patients or patients with T1DM. The types, volume, and attendance rates of SC patients was similar before and after commencement of the drop-in clinic. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

Dropping In a Microgravity Environment (DIME) Contest

NASA Technical Reports Server (NTRS)

2001-01-01

The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. Sandi Thompson of the National Center for Microgravity Research GRC makes a final adjustment to the drop package. This image is from a digital still camera; higher resolution is not available.

Violence and vulnerability of female migrants in drop houses in Arizona: the predictable outcome of a chain reaction of violence.

PubMed

Simmons, William Paul; Menjívar, Cecilia; Téllez, Michelle

2015-05-01

This qualitative research study examines the experiences of immigrant women crossing the U.S./Mexico border and the proliferation of "drop houses" in Arizona as a new phenomenon, one that is often marked by kidnappings and sexual assault. Little research has been published on the violence women face on their journey, and the drop houses have almost completely escaped scholarly analysis. We argue that the drop houses must be seen as a consequence of a "state of emergency" declared by policy makers that led to changes in U.S. national and local immigration policies that fueled what we call a "chain reaction of violence." © The Author(s) 2015.

DPM, Payload Commander Kathy Thornton and Commander Ken Bowersox in Spacelab

NASA Image and Video Library

1995-11-05

STS073-229-014 (20 October - 5 November 1995) --- Astronauts Kathryn C. Thornton, STS-73 payload commander, and Kenneth D. Bowersox, mission commander, observe a liquid drop's activity at the Drop Physics Module (DPM) in the science module aboard the Earth-orbiting Space Shuttle Columbia. The drop is partially visible at the center of the left edge of the frame. The two were joined by three other NASA astronauts and two guest researchers for almost 16-days of in-orbit research in support of the U.S. Microgravity Laboratory (USML-2) mission.

Model of ASTM Flammability Test in Microgravity: Iron Rods

NASA Technical Reports Server (NTRS)

Steinberg, Theodore A; Stoltzfus, Joel M.; Fries, Joseph (Technical Monitor)

2000-01-01

There is extensive qualitative results from burning metallic materials in a NASA/ASTM flammability test system in normal gravity. However, this data was shown to be inconclusive for applications involving oxygen-enriched atmospheres under microgravity conditions by conducting tests using the 2.2-second Lewis Research Center (LeRC) Drop Tower. Data from neither type of test has been reduced to fundamental kinetic and dynamic systems parameters. This paper reports the initial model analysis for burning iron rods under microgravity conditions using data obtained at the LERC tower and modeling the burning system after ignition. Under the conditions of the test the burning mass regresses up the rod to be detached upon deceleration at the end of the drop. The model describes the burning system as a semi-batch, well-mixed reactor with product accumulation only. This model is consistent with the 2.0-second duration of the test. Transient temperature and pressure measurements are made on the chamber volume. The rod solid-liquid interface melting rate is obtained from film records. The model consists of a set of 17 non-linear, first-order differential equations which are solved using MATLAB. This analysis confirms that a first-order rate, in oxygen concentration, is consistent for the iron-oxygen kinetic reaction. An apparent activation energy of 246.8 kJ/mol is consistent for this model.

Bipedal gait model for precise gait recognition and optimal triggering in foot drop stimulator: a proof of concept.

PubMed

Shaikh, Muhammad Faraz; Salcic, Zoran; Wang, Kevin I-Kai; Hu, Aiguo Patrick

2018-03-10

Electrical stimulators are often prescribed to correct foot drop walking. However, commercial foot drop stimulators trigger inappropriately under certain non-gait scenarios. Past researches addressed this limitation by defining stimulation control based on automaton of a gait cycle executed by foot drop of affected limb/foot only. Since gait is a collaborative activity of both feet, this research highlights the role of normal foot for robust gait detection and stimulation triggering. A novel bipedal gait model is proposed where gait cycle is realized as an automaton based on concurrent gait sub-phases (states) from each foot. The input for state transition is fused information from feet-worn pressure and inertial sensors. Thereafter, a bipedal gait model-based stimulation control algorithm is developed. As a feasibility study, bipedal gait model and stimulation control are evaluated in real-time simulation manner on normal and simulated foot drop gait measurements from 16 able-bodied participants with three speed variations, under inappropriate triggering scenarios and with foot drop rehabilitation exercises. Also, the stimulation control employed in commercial foot drop stimulators and single foot gait-based foot drop stimulators are compared alongside. Gait detection accuracy (98.9%) and precise triggering under all investigations prove bipedal gait model reliability. This infers that gait detection leveraging bipedal periodicity is a promising strategy to rectify prevalent stimulation triggering deficiencies in commercial foot drop stimulators. Graphical abstract Bipedal information-based gait recognition and stimulation triggering.

Dosage variability of topical ocular hypotensive products: a densitometric assessment.

PubMed

Gaynes, Bruce I; Singa, Ramesh M; Cao, Ying

2009-02-01

To ascertain consequence of variability in drop volume obtained from multiuse topical ocular hypotensive products in terms of uniformity of product dosage. Densitometric assessment of drop volume dispensed from 2 alternative bottle positions. All except one product demonstrated a statistically significant difference in drop volume when administered at either a 45-degree or 90-degree bottle angle (Student t test, P<0.001). Product-specific drop volume ranged from a nadir of 22.36 microL to a high of 53.54 microL depending on bottle angle of administration. Deviation in drop dose was directly proportional to variability in drop volume. Variability in per drop dosage was conspicuous among products with a coefficient of variation from 1.49% to 15.91%. In accordance with drop volume, all products demonstrated a statistically significant difference in drop dose at 45-degree versus 90-degree administration angles. Drop volume was found unrelated to drop uniformity (Spearman r=0.01987 and P=0.9463). Variability and lack of uniformity in drop dosage is clearly evident among select ocular hypotensive products and is related to angle of drop administration. Erratic dosage of topical ocular hypotensive therapy may contribute in part to therapeutic failure and/or toxicity.

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

NASA Technical Reports Server (NTRS)

Quade, D. A.

1978-01-01

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

Orbiter thermal pressure drop characteristics for shuttle orbiter thermal protection system components: High density tile, low density tile, densified low density tile, and strain isolation pad

NASA Technical Reports Server (NTRS)

Lawing, P. L.; Nystrom, D. M.

1980-01-01

Pressure drop tests were conducted on available samples of low and high density tile, densified low density tile, and strain isolation pads. The results are presented in terms of pressure drop, material thickness and volume flow rate. Although the test apparatus was only capable of a small part of the range of conditions to be encountered in a Shuttle Orbiter flight, the data serve to determine the type of flow characteristics to be expected for each material type tested; the measured quantities also should serve as input for initial venting and flow through analysis.

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

NASA Technical Reports Server (NTRS)

Quade, D. A.

1978-01-01

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

Designing for aircraft structural crashworthiness

NASA Technical Reports Server (NTRS)

Thomson, R. G.; Caiafa, C.

1981-01-01

This report describes structural aviation crash dynamics research activities being conducted on general aviation aircraft and transport aircraft. The report includes experimental and analytical correlations of load-limiting subfloor and seat configurations tested dynamically in vertical drop tests and in a horizontal sled deceleration facility. Computer predictions using a finite-element nonlinear computer program, DYCAST, of the acceleration time-histories of these innovative seat and subfloor structures are presented. Proposed application of these computer techniques, and the nonlinear lumped mass computer program KRASH, to transport aircraft crash dynamics is discussed. A proposed FAA full-scale crash test of a fully instrumented radio controlled transport airplane is also described.

Progress on Concepts for Next-Generation Drop Tower Systems

NASA Astrophysics Data System (ADS)

Könemann, Thorben; Eigenbrod, Christian; Von Kampen, Peter; Laemmerzahl, Claus; Kaczmarczik, Ulrich

2016-07-01

The Center of Applied Space Technology and Microgravity (ZARM) founded by Prof. Dr.-Ing. Hans J. Rath in 1985 is part of the Department of Production Engineering at the University of Bremen, Germany. ZARM is mainly concentrated on fundamental investigations of gravitational and space-related phenomenas under conditions of weightlessness as well as questions and developments related to technologies for space. At ZARM about 100 scientists, engineers, and administrative staff as well as many students from different departments are employed. Today, ZARM is still one of the largest and most important research center for space sciences and technologies in Europe. With a height of 146 m the Bremen Drop Tower is the predominant facility of ZARM and also the only drop tower of its class in Europe. ZARM's ground-based laboratory offers the opportunity for daily short-term experiments under conditions of high-quality weightlessness at a level of 10-6 g (microgravity), which is one of the best achievable for ground-based flight opportunities. Scientists may choose up to three times a day between a single drop experiment with 4.74 s in simple free fall and an experiment in ZARM's worldwide unique catapult system with 9.3 s in weightlessness. Since the start of operation of the facility in 1990, over 7500 drops or catapult launches of more than 160 different experiment types from various scientific fields like fundamental physics, combustion, fluid dynamics, planetary formation / astrophysics, biology and materials sciences have been accomplished so far. In addition, more and more technology tests have been conducted under microgravity conditions at the Bremen Drop Tower in order to effectively prepare appropriate space missions in advance. In this paper we report on the progress on concepts for next-generation drop tower systems based on the GraviTower idea utilizing a guided electro-magnetic linear drive. Alternative concepts motivated by the scientific demand for higher experiment repetition rates are discussed.

Research Pilot Milt Thompson in M2-F2 Aircraft Attached to B-52 Mothership

NASA Image and Video Library

1966-02-28

NASA research pilot Milt Thompson sits in the M2-F2 "heavyweight" lifting body research vehicle before a 1966 test flight. The M2-F2 and the other lifting-body designs were all attached to a wing pylon on NASA’s B-52 mothership and carried aloft. The vehicles were then drop-launched and, at the end of their flights, glided back to wheeled landings on the dry lake or runway at Edwards AFB. The lifting body designs influenced the design of the Space Shuttle and were also reincarnated in the design of the X-38 in the 1990s.

Two phase detonation studies

NASA Technical Reports Server (NTRS)

Nicholls, J. A.; Pierce, T. H.; Miyajima, H.; Oza, R.; Patil, P.

1974-01-01

An experimental study of the passage of a shock wave over a burning fuel drop is described. This includes high speed framing photographs of the interaction taken at 500,000 frames per second. A theoretical prediction of the ignition of a fuel drop by a shock wave is presented and the results compared with earlier experimental work. Experimental attempts to generate a detonation in a liquid fuel drop (kerosene)-liquid oxidizer drop (hydrogen peroxide)-inert gas-environment are described. An appendix is included which gives the analytical prediction of power requirements for the drop generator to produce certain size drops at a certain mass rate. A bibliography is also included which lists all of the publications resulting from this research grant.

Using an Extended Dynamic Drag-and-Drop Assistive Program to Assist People with Multiple Disabilities and Minimal Motor Control to Improve Computer Drag-and-Drop Ability through a Mouse Wheel

ERIC Educational Resources Information Center

Shih, Ching-Hsiang

2012-01-01

Software technology is adopted by the current research to improve the Drag-and-Drop abilities of two people with multiple disabilities and minimal motor control. This goal was realized through a Dynamic Drag-and-Drop Assistive Program (DDnDAP) in which the complex dragging process is replaced by simply poking the mouse wheel and clicking. However,…

The Drop Tower Bremen -An Overview

NASA Astrophysics Data System (ADS)

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

The Center of Applied Space Technology and Microgravity (ZARM) was founded in 1985 as an institute of the University of Bremen, which focuses on research on gravitational and space-related phenomena. In 1988, the construction of ZARM`s drop tower began. Since its inau-guration in September 1990, the eye-catching Drop Tower Bremen with a height of 146m and its characteristic glass roof has become twice a landmark on the campus of the University of Bremen and the emblem of the technology park Bremen. As such an outstanding symbol of space science in Bremen the drop tower provides an european unique facility for experiments under conditions of high-quality weightlessness with residual gravitational accelerations in the microgravity regime. The period of maximum 4.74s of each freely falling experiment at the Drop Tower Bremen is only limited by the height of the drop tower vacuum tube, which was fully manufactured of steal and enclosed by an outer concrete shell. Thus, the pure free fall height of each microgravity drop experiment is approximately 110m. By using the later in-stalled catapult system established in 2004 ZARM`s short-term microgravity laboratory is able to nearly double the time of free fall. This world-wide inimitable capsule catapult system meets scientists` demand of extending the period of weightlessness. During the catapult operation the experiment capsule performs a vertical parabolic flight within the drop tower vacuum tube. In this way the time of microgravity can be extended to slightly over 9s. Either in the drop or in the catapult operation routine the repetition rates of microgravity experiments at ZARM`s drop tower facility are the same, generally up to 3 times per day. In comparison to orbital platforms the ground-based laboratory Drop Tower Bremen represents an economic alternative with a permanent access to weightlessness on earth. Moreover, the exceptional high quality of weightlessness in order of 1e-6 g (in the frequency range below 100Hz) demonstrates a perfect experimental environment for unperturbed investigations of scientific phenomena. Motivated by these prospects many national and international groups have initialized research programs taking advantage of this drop tower facility. In respect thereof the spectrum of research fields and technologies in space-related conditions can be continuously enhanced at ZARM. In the first of our two talks we will give you an overview about the inner structure of ZARM, as well as the service and the operation offered by the ZARM Drop Tower Operation and Service Company (ZARM FAB mbH). The ZARM FAB mbH owned by the State Government of Bremen is a public company maintaining the drop tower facility and supporting experimentalists in scientific and technical questions before, during and after their drop or catapult campaigns. In detail, we will present you important technical drop tower informations, our support and the idea, how you can proceed with your microgravity-related experiment including all your requirements to successfully accomplish an entire drop or catapult campaign. In summary, we will illustrate the complete procedure, how to drop or to catapult an experiment capsule at the Drop Tower Bremen.

40 CFR Table 2 to Subpart Kkkkk of... - Operating Limits

Code of Federal Regulations, 2011 CFR

2011-07-01

.... Maintain the average scrubber pressure drop for each 3-hour block period at or above the average pressure drop established during the performance test; andb. Maintain the average scrubber liquid pH for each 3-hour block period at or above the average scrubber liquid pH established during the performance test...

North American X-15 model tested in 300MPH Low Speed 7x10 Tunnel

NASA Image and Video Library

1958-09-07

A one-twentieth scale model of the X-15 originally suspended beneath the wing of a B-52 is observed by a scientist of the National Aeronautics and Space Administration (NASA) as it leaves the bomber model in tests to determine the release characteristics and drop motion of the research airplane. Caption: The aerodynamics of air launching the North American X-15 being investigated in the 300MPH Low Speed 7x10 Tunnel, about 1957. Photograph published in Engineer in Charge: A History of the Langley Aeronautical Laboratory, 1917-1958 by James R. Hansen. Page 366. Photograph also published in Sixty Years of Aeronautical Research 1917-1977 By David A. Anderton. A NASA publication. Page 49.

Nondestructive spot test method for magnesium and magnesium alloys

NASA Technical Reports Server (NTRS)

Wilson, M. L. (Inventor)

1973-01-01

A method for spot test identification of magnesium and various magnesium alloys commonly used in aerospace applications is described. The spot test identification involves color codes obtained when several drops of 3 M hydrochloric acid are placed on the surface to be tested. After approximately thirty seconds, two drops of this reacted acid is transferred to each of two depressions in a spot plate for additions of other chemicals with subsequent color changes indicating magnesium or its alloy.

Evaluation of ENEPIG and Immersion Silver Surface Finishes Under Drop Loading

NASA Astrophysics Data System (ADS)

Pearl, Adam; Osterman, Michael; Pecht, Michael

2016-01-01

The effect of printed circuit board surface finish on the drop loading reliability of ball grid array (BGA) solder interconnects has been examined. The finishes examined include electroless nickel/electroless palladium/immersion gold (ENEPIG) and immersion silver (ImAg). For the ENEPIG finish, the effect of the Pd plating layer thickness was evaluated by testing two different thicknesses: 0.05 μm and 0.15 μm. BGA components were assembled onto the boards using either eutectic Sn-Pb or Sn-3.0Ag-0.5Cu (SAC305) solder. Prior to testing, the assembled boards were aged at 100°C for 24 h or 500 h. The boards were then subjected to multiple 1500-g drop tests. Failure analysis indicated the primary failure site for the BGAs to be the solder balls at the board-side solder interface. Cratering of the board laminate under the solder-attached pads was also observed. In all cases, isothermal aging reduced the number of drops to failure. The components soldered onto the boards with the 0.15- μm-Pd ENEPIG finish with the SAC305 solder had the highest characteristic life, at 234 drops to failure, compared with the other finish-solder combinations.

Relationships and Dropping Out: The Voice of At-Risk Youth

ERIC Educational Resources Information Center

Henry, Robert Thomas

2009-01-01

The practice of retaining students in grade has been studied, researched, discussed, criticized and yet it continues. Dropping out of school prior to graduation has been studied, researched, discussed, written about and continues to be practiced by our youth. Policymakers are often provided quantitative data to consider as they explore, evaluate,…

X-38 Ship #2 in Free Flight after Release from B-52 Mothership

NASA Technical Reports Server (NTRS)

1999-01-01

The X-38 research vehicle drops away from NASA's B-52 mothership immediately after being released from the B-52's wing pylon. More than 30 years earlier, this same B-52 launched the original lifting-body vehicles flight tested by NASA and the Air Force at what is now called the Dryden Flight Research Center and the Air Force Flight Test Center. NASA B-52, Tail Number 008, is an air launch carrier aircraft, 'mothership,' as well as a research aircraft platform that has been used on a variety of research projects. The aircraft, a 'B' model built in 1952 and first flown on June 11, 1955, is the oldest B-52 in flying status and has been used on some of the most significant research projects in aerospace history. Some of the significant projects supported by B-52 008 include the X-15, the lifting bodies, HiMAT (highly maneuverable aircraft technology), Pegasus, validation of parachute systems developed for the space shuttle program (solid-rocket-booster recovery system and the orbiter drag chute system), and the X-38. The B-52 served as the launch vehicle on 106 X-15 flights and flew a total of 159 captive-carry and launch missions in support of that program from June 1959 to October 1968. Information gained from the highly successful X-15 program contributed to the Mercury, Gemini, and Apollo human spaceflight programs as well as space shuttle development. Between 1966 and 1975, the B-52 served as the launch aircraft for 127 of the 144 wingless lifting body flights. In the 1970s and 1980s, the B-52 was the launch aircraft for several aircraft at what is now the Dryden Flight Research Center, Edwards, California, to study spin-stall, high-angle-of attack, and maneuvering characteristics. These included the 3/8-scale F-15/spin research vehicle (SRV), the HiMAT (Highly Maneuverable Aircraft Technology) research vehicle, and the DAST (drones for aerodynamic and structural testing). The aircraft supported the development of parachute recovery systems used to recover the space shuttle solid rocket booster casings. It also supported eight orbiter (space shuttle) drag chute tests in 1990. In addition, the B-52 served as the air launch platform for the first six Pegasus space boosters. During its many years of service, the B-52 has undergone several modifications. The first major modification was made by North American Aviation (now part of Boeing) in support of the X-15 program. This involved creating a launch-panel-operator station for monitoring the status of the test vehicle being carried, cutting a large notch in the right inboard wing flap to accommodate the vertical tail of the X-15 aircraft, and installing a wing pylon that enables the B-52 to carry research vehicles and test articles to be air-launched/dropped. Located on the right wing, between the inboard engine pylon and the fuselage, this wing pylon was subjected to extensive testing prior to its use. For each test vehicle the B-52 carried, minor changes were made to the launch-panel operator's station. Built originally by the Boeing Company, the NASA B-52 is powered by eight Pratt & Whitney J57-19 turbojet engines, each of which produce 12,000 pounds of thrust. The aircraft's normal launch speed has been Mach 0.8 (about 530 miles per hour) and its normal drop altitude has been 40,000 to 45,000 feet. It is 156 feet long and has a wing span of 185 feet. The heaviest load it has carried was the No. 2 X-15 aircraft at 53,100 pounds. Project manager for the aircraft is Roy Bryant.

PATHFINDER ATOMIC POWER PLANT. FILTRATION OF ALUMINUM CORROSION PRODUCTS PRODUCED IN HIGH-TEMPERATURE, HIGH PURITY WATER SYSTEMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noble, J.H.; Davie, R.L.

1961-05-01

Filter tests were conducted to determine the most suitable filter for removing large quantities of aluminum corrosion product (boehmite) from reactor water. Filters tested included the following: wire-wound, sintered filter elements, sintered ceramic fllter elements, cotton stringwound filter elements, felted-cotton filter elements, cation resin, adsorption resin, diatomaceous earth precoat filter, and a wood-cellulose precoat filter. Parameters measured were flow rate, filter-influent and -effluent boehmite concentration, pressure drop, and final filter load. The pressure drop and efficiency of the filters was correlated with boehmite load. Boehmite deposits on filters as a nonporous gelatinous cake, and causes a rapidly increasing pressure drop.more » Tests indicate that the optimum load with filter elements and precoat filters is achieved at a pressure drop of 25 psi. Very little additional load can be obtained by operating to a higher pressure drop. Of the filters tested, the precoat filter snd 40 to 60 mesh cation resin were the more effective in removing boehmite. The efficiency of the precoat filter was in excess of 99%, and the efficiency of the cation resin was for the most part in excess of 95%. For various reasons, the other filters were eliminated from final consideration. The test program and available literature indicated that an element type precoat filter using wood cellulose as the precoat media would be most suitable for the proposed application. (auth)« less

Shape oscillations of acoustically levitated drops in water: Early research with Bob Apfel on modulated radiation pressure

NASA Astrophysics Data System (ADS)

Marston, Philip L.

2004-05-01

In 1976, research in collaboration with Bob Apfel demonstrated that low-frequency shape oscillations of hydrocarbon drops levitated in water could be driven using modulated radiation pressure. While that response to modulated ultrasound was subsequently extended to a range of systems, the emphasis here is to recall the initial stages of development in Bob Apfel's laboratory leading to some publications [P. L. Marston and R. E. Apfel, J. Colloid Interface Sci. 68, 280-286 (1979); J. Acoust. Soc. Am. 67, 27-37 (1980)]. The levitation technology used at that time was such that it was helpful to develop a sensitive method for detecting weak oscillations using the interference pattern in laser light scattered by levitated drops. The initial experiments to verify this scattering method used shape oscillations induced by modulated electric fields within the acoustic levitator. Light scattering was subsequently used to detect shape oscillations induced by amplitude modulating a carrier having a high frequency (around 680 kHz) at a resonance of the transducer. Methods were also developed for quantitative measurements of the drop's response and with improved acoustic coupling drop fission was observed. The connection with research currently supported by NASA will also be noted.

Low velocity impact of 6082-T6 aluminum plates

NASA Astrophysics Data System (ADS)

Mocian, Oana Alexandra; Constantinescu, Dan Mihai; Sandu, Marin; Sorohan, Ştefan

2018-02-01

The low velocity domain covers vehicle impacts, ship collisions and even accidentally tool drops. Even though more and more research is needed into these fields, most of the papers concerning impact problems focus on impact at medium and high velocities. Understanding the behavior of structures subjected to low velocity impact is of major importance when referring to impact resistance and damage tolerance. The paper presents an experimental and numerical investigation on the low velocity behavior of 6082-T6 aluminum plates. Impact tests were performed using an Instron Ceast 9340 drop-weight testing machine. In the experimental procedure, square plates were mounted on a circular support, fixed with a pneumatic clamping system and impacted with a hemispherical steel projectile. Specimens were impacted at constant weight and different impact velocities. The effect of different impact energies was investigated. The impact event was then simulated using the nonlinear finite element code LS_DYNA in order to determine the effect of strain rate upon the mechanical behavior of the aluminum plates. Moreover, in order to capture the exact behavior of the material, a special attention has been given to the selection of the correct material model and its parameters, which, in large extent, depend on the observed behavior of the aluminum plate during the test and the actual response of the plate under simulation. The numerical predictions are compared with the experimental observations and the applicability of the numerical model for further researches is analyzed.

Process analytical technology to understand the disintegration behavior of alendronate sodium tablets.

PubMed

Xu, Xiaoming; Gupta, Abhay; Sayeed, Vilayat A; Khan, Mansoor A

2013-05-01

Various adverse events including esophagus irritations have been reported with the use of alendronate tablets, likely attributed to the rapid tablet disintegration in the mouth or esophagus. Accordingly, the disintegration of six alendronate tablet drug products was studied using a newly developed testing device equipped with in-line sensors, in addition to the official compendial procedure for measuring the disintegration time. The in-line sensors were used to monitor the particle count and solution pH change to assess the onset and duration of disintegration. A relatively large variation was observed in the disintegration time of the tested drug products using the compendial method. The data collected using the in-line sensors suggested that all tested drug products exhibited almost instantaneous onset of disintegration, under 2 s, and a sharp drop in solution pH. The drop in pH was slower for tablets with slower disintegration. The in-house prepared alendronate test tablets also showed similar trends suggesting rapid solubilization of the drug contributed to the fast tablet disintegration. This research highlights the usefulness of the newly developed in-line analytical method in combination with the compendial method in providing a better understanding of the disintegration and the accompanying drug solubilization processes for fast disintegrating tablet drug products. Copyright © 2013 Wiley Periodicals, Inc.

Osmolarity of prevalent eye drops, side effects, and therapeutic approaches.

PubMed

Dutescu, Ralf M; Panfil, Claudia; Schrage, Norbert

2015-05-01

Little is known about how the osmolarity of ophthalmic formulations affects the ocular surface. Because hyperosmolar eye drops could be therapeutic for treating corneal edema, this article presents an ex vivo model of corneal edema for testing ophthalmic drugs based on their osmolarity. The respective osmolarity of common eye drops found in the German market is also analyzed here. For modeling corneal edema, an Ex Vivo Eye Irritation Test was used to simulate an ocular anterior chamber with a physiological corneal barrier. To induce corneal edema, the anterior chamber was supplied with a hypoosmolar medium (148 mOsm/L) for 24 hours. Preserved and preservative-free 5% sodium chloride (hyperosmolar Omnisorb and Ocusalin 5% UD) were used for 1 hour, on 5 corneas each, to test their efficiency to reduce corneal edema in this model. Corneal thickness was determined by optical coherence tomography. Osmolarity of 87 common eye drops was measured by freezing point osmometry. Ex vivo, the tested hypoosmolar condition induced corneal edema from 450 μm (±50 μm) at baseline to 851 μm (±94 μm, P < 0.0001). Omnisorb and Ocusalin 5% UD significantly reduced the corneal thickness by 279 μm (±28 μm, P < 0.001) for Omnisorb and 258 μm (±29 μm, P < 0.001) for Ocusalin 5% UD. Forty-three (49%) of the tested products had an osmolarity below and 44 (51%) above the physiological tear osmolarity of 289 mOsm/L. Osmolarity values of less than 200 mOsm/L were found in lubricant drops. The highest osmolarity was detected in Omnisorb (1955 mOsm/L). The Ex Vivo Eye Irritation Test has proven to be a reliable novel model of corneal edema for evaluating osmotic eye drops. Osmolarity measurements revealed a wide range from hypotonic to hypertonic formulations for commonly marketed ophthalmic drugs.

Taking the Easy Way Out: How the GED Testing Program Induces Students to Drop Out. NBER Working Paper No. 14044

ERIC Educational Resources Information Center

Heckman, James J.; LaFontaine, Paul A.; Rodriguez, Pedro L.

2008-01-01

We exploit an exogenous increase in General Educational Development (GED) testing requirements to determine whether raising the difficulty of the test causes students to finish high school rather than drop out and GED certify. We find that a six point decrease in GED pass rates induces a 1.3 point decline in overall dropout rates. The effect size…

Experimental and numerical study of drill bit drop tests on Kuru granite.

PubMed

Fourmeau, Marion; Kane, Alexandre; Hokka, Mikko

2017-01-28

This paper presents an experimental and numerical study of Kuru grey granite impacted with a seven-buttons drill bit mounted on an instrumented drop test machine. The force versus displacement curves during the impact, so-called bit-rock interaction (BRI) curves, were obtained using strain gauge measurements for two levels of impact energy. Moreover, the volume of removed rock after each drop test was evaluated by stereo-lithography (three-dimensional surface reconstruction). A modified version of the Holmquist-Johnson-Cook (MHJC) material model was calibrated using Kuru granite test results available from the literature. Numerical simulations of the single drop tests were carried out using the MHJC model available in the LS-DYNA explicit finite-element solver. The influence of the impact energy and additional confining pressure on the BRI curves and the volume of the removed rock is discussed. In addition, the influence of the rock surface shape before impact was evaluated using two different mesh geometries: a flat surface and a hyperbolic surface. The experimental and numerical results are compared and discussed in terms of drilling efficiency through the mechanical specific energy.This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'. © 2016 The Author(s).

Experimental and numerical study of drill bit drop tests on Kuru granite

PubMed Central

Kane, Alexandre; Hokka, Mikko

2017-01-01

This paper presents an experimental and numerical study of Kuru grey granite impacted with a seven-buttons drill bit mounted on an instrumented drop test machine. The force versus displacement curves during the impact, so-called bit–rock interaction (BRI) curves, were obtained using strain gauge measurements for two levels of impact energy. Moreover, the volume of removed rock after each drop test was evaluated by stereo-lithography (three-dimensional surface reconstruction). A modified version of the Holmquist–Johnson–Cook (MHJC) material model was calibrated using Kuru granite test results available from the literature. Numerical simulations of the single drop tests were carried out using the MHJC model available in the LS-DYNA explicit finite-element solver. The influence of the impact energy and additional confining pressure on the BRI curves and the volume of the removed rock is discussed. In addition, the influence of the rock surface shape before impact was evaluated using two different mesh geometries: a flat surface and a hyperbolic surface. The experimental and numerical results are compared and discussed in terms of drilling efficiency through the mechanical specific energy. This article is part of the themed issue ‘Experimental testing and modelling of brittle materials at high strain rates’. PMID:27956511

Educational Subculture and Dropping out in Higher Education: A Longitudinal Case Study

ERIC Educational Resources Information Center

Venuleo, C.; Mossi, P.; Salvatore, S.

2016-01-01

The paper tests longitudinally the hypothesis that educational subcultures in terms of which students interpret their role and their educational setting affect the probability of dropping out of higher education. A logistic regression model was performed to predict drop out at the beginning of the second academic year for the 823 freshmen of a…

Structural Equation Modeling of Retention and Overage Effects on Dropping Out of School.

ERIC Educational Resources Information Center

Grissom, James B.; Shepard, Lorrie A.

This study addresses the effect that grade retention has on dropping out of school. A structural model was developed to test the effect of grade retention on dropping out while controlling for the effects of other possible mediating variables, especially achievement. This model with slight modifications was applied across four different school…

Thermal stabilities of drops of burning thermoplastics under the UL 94 vertical test conditions.

PubMed

Wang, Yong; Zhang, Jun

2013-02-15

The properties of polymer melts will strongly affect the fire hazard of the pool induced by polymer melt flow. In this study the thermal stabilities of eight thermoplastic polymers as well as their melting drops generated under the UL 94 vertical burning test conditions were investigated by thermogravimetric experiments. It was found that the kinetic compensation effect existed for the decomposition reactions of the polymers and their drops. For polymethylmethacrylate (PMMA), high impact polystyrene (HIPS), poly(acrylonitrile-butadiene-styrene) (ABS), polyamide 6 (PA6), polypropylene (PP) and low density polyethylene (LDPE), the onset decomposition temperature and the two decomposition kinetic parameters (the pre-exponential factor and the activation energy) of the drop were less than those of the polymer. However, the onset decomposition temperature and the two kinetic parameters of PC's drop were greater than those of polycarbonate (PC). Interestingly, for polyethylenevinylacetate (EVA18) the drop hardly contained the vinyl acetate chain segments. Similarly, for the PMMA/LDPE blends and the PMMA/PP blends, when the volume fraction of PMMA was less than 50% the drop hardly contained PMMA, implying that the blend would not drip until PMMA burned away and its surface temperature approached the decomposition temperature of the continuous phase composed of LDPE or PP. Copyright © 2012 Elsevier B.V. All rights reserved.

When Volunteering Is Mandatory: A Call for Research about Service Learning

ERIC Educational Resources Information Center

Cloyd, Melissa

2017-01-01

Stakeholders have long been concerned about high school drop-out rates and associated achievement gaps between groups, specifically racial, of high school students. While significant improvements have been made to these drop-out rates at the national level, the largest group of drop-out students continues to be those of Hispanic heritage. Research…

Silicon Carbide Diodes Characterization at High Temperature and Comparison With Silicon Devices

NASA Technical Reports Server (NTRS)

Lebron-Velilla, Ramon C.; Schwarze, Gene E.; Gardner, Brent G.; Adams, Jerry D., Jr.

2004-01-01

Commercially available silicon carbide (SiC) Schottky diodes from different manufacturers rated at 200, 300, 600, and 1200 V, were electrically tested and characterized as a function of temperature up to 300 C. Electrical tests included both steady state and dynamic tests. Steady state tests produced forward and reverse I-V characteristic curves. Transient tests evaluated the switching performance of the diodes in either a hard-switched DC to DC buck converter or a half-bridge boost converter. For evaluation and comparison purposes, the same tests were performed with current state-of-the-art ultra fast silicon (Si) pn-junction diodes of similar ratings and also a Si Schottky diode. The comparisons made were forward voltage drop at rated current, reverse current at rated voltage, and turn-off peak reverse recovery current and reverse recovery time. In addition, efficiency measurements were taken for the buck DC to DC converter using both the SiC Schottky diodes and the Si pn-junction diodes at different temperatures and frequencies. The test results showed that at high temperature, the forward voltage drop for SiC Schottky diodes is higher than the forward drop of the ultra fast Si pn-junction diodes. As the temperature increased, the forward voltage drop of the SiC Schottky increased while for the ultra fast Si pn-junction diodes, the forward voltage drop decreased as temperature increased. For the elevated temperature steady state reverse voltage tests, the SiC Schottky diodes showed low leakage current at their rated voltage. Likewise, for the transient tests, the SiC Schottky diodes displayed low reverse recovery currents over the range of temperatures tested. Conversely, the Si pn-junction diodes showed increasing peak reverse current values and reverse recovery times with increasing temperature. Efficiency measurements in the DC to DC buck converter showed the advantage of the SiC Schottky diodes over the ultra fast Si pn-junction diodes, especially at the higher temperatures and higher frequencies.

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

NASA Technical Reports Server (NTRS)

1995-01-01

A 4-foot-long model of NASA's X-38, an experimental crew return vehicle, glides to earth after being dropped from a Cessna aircraft in late 1995. The model was used to test the ram-air parafoil landing system, which could allow for accurate and controlled landings of an emergency Crew Return Vehicle spacecraft returning to Earth. The X-38 Crew Return Vehicle (CRV) research project is designed to develop the technology for a prototype emergency crew return vehicle, or lifeboat, for the International Space Station. The project is also intended to develop a crew return vehicle design that could be modified for other uses, such as a joint U.S. and international human spacecraft that could be launched on the French Ariane-5 Booster. The X-38 project is using available technology and off-the-shelf equipment to significantly decrease development costs. Original estimates to develop a capsule-type crew return vehicle were estimated at more than $2 billion. X-38 project officials have estimated that development costs for the X-38 concept will be approximately one quarter of the original estimate. Off-the-shelf technology is not necessarily 'old' technology. Many of the technologies being used in the X-38 project have never before been applied to a human-flight spacecraft. For example, the X-38 flight computer is commercial equipment currently used in aircraft and the flight software operating system is a commercial system already in use in many aerospace applications. The video equipment for the X-38 is existing equipment, some of which has already flown on the space shuttle for previous NASA experiments. The X-38's primary navigational equipment, the Inertial Navigation System/Global Positioning System, is a unit already in use on Navy fighters. The X-38 electromechanical actuators come from previous joint NASA, U.S. Air Force, and U.S. Navy research and development projects. Finally, an existing special coating developed by NASA will be used on the X-38 thermal tiles to make them more durable than those used on the space shuttles. The X-38 itself was an unpiloted lifting body designed at 80 percent of the size of a projected emergency crew return vehicle for the International Space Station, although two later versions were planned at 100 percent of the CRV size. The X-38 and the actual CRV are patterned after a lifting-body shape first employed in the Air Force-NASA X-24 lifting-body project in the early to mid-1970s. The current vehicle design is base lined with life support supplies for about nine hours of orbital free flight from the space station. It's landing will be fully automated with backup systems which allow the crew to control orientation in orbit, select a deorbit site, and steer the parafoil, if necessary. The X-38 vehicles (designated V131, V132, and V-131R) are 28.5 feet long, 14.5 feet wide, and weigh approximately 16,000 pounds on average. The vehicles have a nitrogen-gas-operated attitude control system and a bank of batteries for internal power. The actual CRV to be flown in space was expected to be 30 feet long. The X-38 project is a joint effort between the Johnson Space Center, Houston, Texas (JSC), Langley Research Center, Hampton, Virginia (LaRC) and Dryden Flight Research Center, Edwards, California (DFRC) with the program office located at JSC. A contract was awarded to Scaled Composites, Inc., Mojave, California, for construction of the X-38 test airframes. The first vehicle was delivered to the JSC in September 1996. The vehicle was fitted with avionics, computer systems and other hardware at Johnson. A second vehicle was delivered to JSC in December 1996. Flight research with the X-38 at Dryden began with an unpiloted captive-carry flight in which the vehicle remained attached to its future launch vehicle, Dryden's B-52 008. There were four captive flights in 1997 and three in 1998, plus the first drop test on March 12, 1998, using the parachutes and parafoil. Further captive and drop tests occurred in 1999. In March 2000 Vehicle 132 completed its third and final free flight in the highest, fastest, and longest X-38 flight to date. It was released at an altitude of 39,000 feet and flew freely for 45 seconds, reaching a speed of over 500 miles per hour before deploying its parachutes for a landing on Rogers Dry Lakebed. In the drop tests, the X-38 vehicles have been autonomous after airlaunch from the B-52. After they deploy the parafoil, they have remained autonomous, but there is also a manual mode with controls from the ground.

Reductions in Hard Drug Use Among Homeless Youth Receiving a Strength-Based Outreach Intervention: Comparing the Long-Term Effects of Shelter Linkage Versus Drop-in Center Linkage.

PubMed

Guo, Xiamei; Slesnick, Natasha

2017-06-07

The current study sought to test hard drug use outcomes for youth receiving a strengths-based outreach and advocacy intervention that linked youth to either a shelter or a drop-in center. Homeless youth (14-24 years old) were engaged by research assistants (RAs) at soup kitchens, parks, libraries, and other locations that homeless youth were known to frequent. Youth were randomly assigned to receive six months of advocacy that focused on linking youth to a drop-in center (n = 40) or to a crisis shelter (n = 39). Follow-up assessments were conducted at 3, 6, and 9 months post-baseline. Hard drug use over time was the main outcome. Intervention condition and service connection were used as predictors for the baseline level and the slope of change in hard drug use over time. Data analysis was conducted with Bernoulli Hierarchical Generalized Linear Modeling in HLM7. The current study found that those who were in the drop-in linkage condition exhibited a greater reduction in their odds of using hard drugs during the follow-up points than their counterparts in the shelter linkage condition. And finally, those who utilized services more often during the follow-ups were those who exhibited less hard drug use at baseline and less reduction in their odds of using hard drugs. This study suggests that drop-in centers, which are often characterized by low-demand programming and few behavioral restrictions, are effective for addressing hard drug use among homeless youth.

Systems development of a stall/spin research facility using remotely controlled/augmented aircraft models. Volume 1: Systems overview

NASA Technical Reports Server (NTRS)

Montoya, R. J.; Jai, A. R.; Parker, C. D.

1979-01-01

A ground based, general purpose, real time, digital control system simulator (CSS) is specified, developed, and integrated with the existing instrumentation van of the testing facility. This CSS is built around a PDP-11/55, and its operational software was developed to meet the dual goal of providing the immediate capability to represent the F-18 drop model control laws and the flexibility for expansion to represent more complex control laws typical of control configured vehicles. Overviews of the two CSS's developed are reviewed as well as the overall system after their integration with the existing facility. Also the latest version of the F-18 drop model control laws (REV D) is described and the changes needed for its incorporation in the digital and analog CSS's are discussed.

The Effects of Scales on Autorotation of Monarch Butterfly Forewings

NASA Astrophysics Data System (ADS)

Dechello, Nicole; Lang, Amy

2014-11-01

The wings of Monarch butterflies (Danus plexippus) have scales of approximately 100 micrometers that cover their wings in a roof-shingle pattern, and these scales are hypothesized to help improve flight efficiency for their long migration. The aerodynamic effects of the scales, particularly involving the leading edge vortex formation and resulting lift, were investigated by observing the natural autorotation of forewing specimen when dropped in quiescent air. A high-speed camera recorded drop tests of 32 forewings both with scales and after removal of the scales. It was found that the scales, on average, comprised 17% of the forewing mass. Tracking software was used to analyze the videos for several parameters, including descent speed and radius of rotation. NSF ECE Grant #1358991 supported the first author as an research experience for undergraduate (REU) student.

Shoe drop reduction influences the lower limb biomechanics of children tennis players during an open stance forehand: A longitudinal study.

PubMed

Herbaut, Alexis; Simoneau-Buessinger, Emilie; Barbier, Franck; Gillet, Christophe; Roux, Maxime; Guéguen, Nils; Chavet, Pascale

2017-11-01

Compared to traditional tennis shoes, using 0-drop shoes was shown to induce an immediate switch from rear- to forefoot strike pattern to perform an open stance tennis forehand for 30% of children tennis players. The purpose of the study was to examine the long-term effects of a gradual reduction in the shoe drop on the biomechanics of children tennis players performing open stance forehands. Thirty children tennis players participated in 2 laboratory biomechanical test sessions (intermediate: +4 months and final: +8 months) after an inclusion visit where they were randomly assigned to control (CON) or experimental (EXP) group. CON received 12-mm-drop shoes twice, whereas EXP received 8 mm then 4-mm-drop shoes. Strike index indicated that all CON were rearfoot strikers in intermediate and final test sessions. All EXP were rearfoot strikers in intermediate test session, but half the group switched towards a forefoot strike pattern in final test session. This switch resulted in a decreased loading rate of the ground reaction force (-73%, p = .005) but increased peak ankle plantarflexors moment (+47%, p = .050) and peak ankle power absorption (+107%, p = .005) for these participants compared with CON. Biomechanical changes associated with the long-term use of partial minimalist shoes suggest a reduction in heel compressive forces but an increase in Achilles tendon tensile forces.

Experimental and analytical determination of characteristics affecting light aircraft landing-gear dynamics

NASA Technical Reports Server (NTRS)

Fasanella, E. L.; Mcgehee, J. R.; Pappas, M. S.

1977-01-01

An experimental and analytical investigation was conducted to determine which characteristics of a light aircraft landing gear influence gear dynamic behavior significantly. The investigation focused particularly on possible modification for load control. Pseudostatic tests were conducted to determine the gear fore-and-aft spring constant, axial friction as a function of drag load, brake pressure-torque characteristics, and tire force-deflection characteristics. To study dynamic tire response, vertical drops were conducted at impact velocities of 1.2, 1.5, and 1.8 m/s onto a level surface; to determine axial-friction effects, a second series of vertical drops were made at 1.5 m/s onto surfaces inclined 5 deg and 10 deg to the horizontal. An average dynamic axial-friction coefficient of 0.15 was obtained by comparing analytical data with inclined surface drop test data. Dynamic strut bending and associated axial friction were found to be severe for the drop tests on the 10 deg surface.

LOX/Hydrogen Coaxial Injector Atomization Test Program

NASA Technical Reports Server (NTRS)

Zaller, M.

1990-01-01

Quantitative information about the atomization of injector sprays is needed to improve the accuracy of computational models that predict the performance and stability margin of liquid propellant rocket engines. To obtain this data, a facility for the study of spray atomization is being established at NASA-Lewis to determine the drop size and velocity distributions occurring in vaporizing liquid sprays at supercritical pressures. Hardware configuration and test conditions are selected to make the cold flow simulant testing correspond as closely as possible to conditions in liquid oxygen (LOX)/gaseous H2 rocket engines. Drop size correlations from the literature, developed for liquid/gas coaxial injector geometries, are used to make drop size predictions for LOX/H2 coaxial injectors. The mean drop size predictions for a single element coaxial injector range from 0.1 to 2000 microns, emphasizing the need for additional studies of the atomization process in LOX/H2 engines. Selection of cold flow simulants, measured techniques, and hardware for LOX/H2 atomization simulations are discussed.

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MedlinePlus

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Prospective, randomized, controlled comparison of SYSTANE UD eye drops versus VISINE INTENSIV 1% EDO eye drops for the treatment of moderate dry eye.

PubMed

Jacobi, Christina; Kruse, Friedrich E; Cursiefen, Claus

2012-12-01

The aim of this prospective, randomized, clinical, single-center study was to compare the safety and efficacy of 2 ocular surface lubricant eye drops: preservative-free hydroxypropyl (HP)-Guar (SYSTANE UD(®)) eye drops versus preservative-free Tamarindus indica seed polysaccharide (TSP) 1% (VISINE INTENSIV 1% EDO(®)) eye drops. Fifty-six eyes of 28 patients with moderate keratoconjunctivitis sicca (DEWS severity level 2) were enrolled in the trial. Patients were randomized for 2 treatment groups (SYSTANE UD eye drops vs. VISINE INTENSIV 1% EDO eye drops). The eye drops in both groups were applied 5 times per day for 3 months. Statistical analyses were performed using Statistica™ software (Mann-Whitney U-test and Wilcoxon test). P-Values<0.05 were considered significant. After 3 months of treatment the patients of both groups had subjective benefit in the relief of symptoms of dry eye disease evaluated by the Ocular Surface Disease Index (OSDI) questionnaire score. Patients treated with HP-Guar and TSP showed improvements in tear film stability measured by tear break-up time (TBUT), which are statistically significant in the HP-Guar group (P=0.02). The results of this clinical trial show improvements of symptoms and signs in patients with moderate dry eye after the consistent use of preservative-free HP-Guar and TSP lubricant eye drops. Both artificial tear formulations produce amelioration in tear film stability improving eye conditions and patient quality of life. HP-Guar seems to be slightly more effective in improving ocular surface protection by decreasing tear film evaporation.

A new testing station about full-scale testing for rockfall protection systems

NASA Astrophysics Data System (ADS)

Bost, Marion; Dubois, Laurent; Rocher-Lacoste, Frédéric

2010-05-01

Rock blocks which detach from slopes overhanging urban areas, roads, railways and other infrastructures create one of the most frequent hazards in mountainous areas. Some of protection systems against rockfalls are designed to mitigate the effects of a foreseen movement by intercepting and stopping falling rock blocks. Despite the worldwide application of this kind of protections, the global behaviour of such a system has been poorly investigated, for the time being, and only at a reduced scale. The behaviour of these protection systems at real scale has been widely extrapolated, however these theories have still not been investigated by performing relating test at scale 1. The French Public Work Laboratory (LCPC) has decided to build a new testing station to work on that topic. This new testing station located in French Alps is able to drop heavy loads (up to 20 tons) from the top of a cliff down to structural systems in order to test their resistance to big shocks and study their dynamical behaviour at this high energy level. As the fall height can reach near 70m, the impact velocity can actually reach 35 metres per second and the energy released during the impact can be as large as 13 500 kilojoules. The experimental area at the bottom of the cliff which can be impacted by a block is 12 metres wide. This allows to test not only rockfall protection systems at scale 1 but also some parts of building structures too. To avoid damaging test-structure during a block drop due to dynamical effects, the dropping hook was designed with a special system. This one consists of a reversed mass which can be adapted to the dropped block and dropped together with the block. Moreover, it is very important to pay attention on repeatability of results concerning new devices for experiments. Whatever fall height the impact point is hit so with a precision of 50 centimetres. Such an experimental facility needs to be equipped with a relevant instrumentation. High capacity stress sensors, accelerometers and high speed cameras are available for experiments. They have been chosen for their capacity to work with an important length of cables. The monitoring with these experimental devices is performed at a high sample frequency suitable and for a very short load like an impact. A radio controlled system allows triggering monitoring and dropping at the same time. Due to bounce risk with the dropped block the safety of personal is ensured by strict operating rules. An observation platform has been located on an embankment along the test-site in order to follow experiments without risk. Two years were necessary for the test-site construction and its equipment. First tests on rockfall nets fences were performed at the end of 2009.

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

NASA Technical Reports Server (NTRS)

Jackson, Karen E.; Fasanella, Edwin L.

2004-01-01

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

49 CFR 178.810 - Drop test.

Code of Federal Regulations, 2012 CFR

2012-10-01

... solutions with a minimum specific gravity of 0.95 for testing at −18 °C (0 °F) or lower are considered... with a capacity of 0.45 cubic meters (15.9 cubic feet) or less must be subject to an additional drop... material having essentially the same physical characteristics. (3) The specific gravity and viscosity of a...

49 CFR 178.810 - Drop test.

Code of Federal Regulations, 2011 CFR

2011-10-01

... solutions with a minimum specific gravity of 0.95 for testing at −18 °C (0 °F) or lower are considered... with a capacity of 0.45 cubic meters (15.9 cubic feet) or less must be subject to an additional drop... material having essentially the same physical characteristics. (3) The specific gravity and viscosity of a...

49 CFR 178.810 - Drop test.

Code of Federal Regulations, 2014 CFR

2014-10-01

... solutions with a minimum specific gravity of 0.95 for testing at −18 °C (0 °F) or lower are considered... with a capacity of 0.45 cubic meters (15.9 cubic feet) or less must be subject to an additional drop... material having essentially the same physical characteristics. (3) The specific gravity and viscosity of a...

Study of Critical Heat Flux and Two-Phase Pressure Drop Under Reduced Gravity

NASA Technical Reports Server (NTRS)

Abdollahian, Davood; Quintal, Joseph; Barez, Fred; Zahm, Jennifer; Lohr, Victor

1996-01-01

The design of the two-phase flow systems which are anticipated to be utilized in future spacecraft thermal management systems requires a knowledge of two-phase flow and heat transfer phenomena in reduced gravities. This program was funded by NASA headquarters in response to NRA-91-OSSA-17 and was managed by Lewis Research Center. The main objective of this program was to design and construct a two-phase test loop, and perform a series of normal gravity and aircraft trajectory experiments to study the effect of gravity on the Critical Heat Flux (CHF) and onset of instability. The test loop was packaged on two aircraft racks and was also instrumented to generate data for two-phase pressure drop. The normal gravity tests were performed with vertical up and downflow configurations to bound the effect of gravity on the test parameters. One set of aircraft trajectory tests was performed aboard the NASA DC-9 aircraft. These tests were mainly intended to evaluate the test loop and its operational performance under actual reduced gravity conditions, and to produce preliminary data for the test parameters. The test results were used to demonstrate the applicability of the normal gravity models for prediction of the two-phase friction pressure drop. It was shown that the two-phase friction multipliers for vertical upflow and reduced gravity conditions can be successfully predicted by the appropriate normal gravity models. Limited critical heat flux data showed that the measured CHF under reduced gravities are of the same order of magnitude as the test results with vertical upflow configuration. A simplified correlation was only successful in predicting the measured CHF for low flow rates. Instability tests with vertical upflow showed that flow becomes unstable and critical heat flux occurs at smaller powers when a parallel flow path exists. However, downflow tests and a single reduced gravity instability experiment indicated that the system actually became more stable with a parallel single-phase flow path. Several design modifications have been identified which will improve the system performance for generating reduced gravity data. The modified test loop can provide two-phase flow data for a range of operating conditions and can serve as a test bed for component evaluation.

Vertical Drop Testing and Analysis of the Wasp Helicopter Skid Gear

NASA Technical Reports Server (NTRS)

Jackson, Karen E.; Fuchs, Yvonne T.

2007-01-01

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

Asymmetric ratchet effect for directional transport of fog drops on static and dynamic butterfly wings.

PubMed

Liu, Chengcheng; Ju, Jie; Zheng, Yongmei; Jiang, Lei

2014-02-25

Inspired by novel creatures, researchers have developed varieties of fog drop transport systems and made significant contributions to the fields of heat transferring, water collecting, antifogging, and so on. Up to now, most of the efforts in directional fog drop transport have been focused on static surfaces. Considering it is not practical to keep surfaces still all the time in reality, conducting investigations on surfaces that can transport fog drops in both static and dynamic states has become more and more important. Here we report the wings of Morpho deidamia butterflies can directionally transport fog drops in both static and dynamic states. This directional drop transport ability results from the micro/nano ratchet-like structure of butterfly wings: the surface of butterfly wings is composed of overlapped scales, and the scales are covered with porous asymmetric ridges. Influenced by this special structure, fog drops on static wings are transported directionally as a result of the fog drops' asymmetric growth and coalescence. Fog drops on vibrating wings are propelled directionally due to the fog drops' asymmetric dewetting from the wings.

Lightweight Electronic Camera for Research on Clouds

NASA Technical Reports Server (NTRS)

Lawson, Paul

2006-01-01

"Micro-CPI" (wherein "CPI" signifies "cloud-particle imager") is the name of a small, lightweight electronic camera that has been proposed for use in research on clouds. It would acquire and digitize high-resolution (3- m-pixel) images of ice particles and water drops at a rate up to 1,000 particles (and/or drops) per second.

The X-38 vehicle #131R arrives at NASA Dryden Flight Research Center

NASA Image and Video Library

2000-07-11

The X-38 Vehicle 131R, intended to prove the utility of a "lifeboat" crew return vehicle to bring crews home from the International Space Station in the event of an emergency, was unloaded from NASA's Super Guppy transport aircraft on July 11, 2000. The newest X-38 version arrived at Dryden for drop tests from NASA's venerable B-52 mother ship. The tests will evaluate a 7,500 square-foot parafoil intended to permit the crew return vehicle to return from space and land in the length of a football field.

The X-38 vehicle #131R arrives at NASA Dryden Flight Research Center

NASA Technical Reports Server (NTRS)

2000-01-01

The X-38 Vehicle 131R, intended to prove the utility of a 'lifeboat' crew return vehicle to bring crews home from the International Space Station in the event of an emergency, was unloaded from NASA's Super Guppy transport aircraft on July 11, 2000. The newest X-38 version arrived at Dryden for drop tests from NASA's venerable B-52 mother ship. The tests will evaluate a 7,500 square-foot parafoil intended to permit the crew return vehicle to return from space and land in the length of a football field.

Microstructure and strain-stress analysis of the dynamic strain aging in inconel 625 at high temperature

NASA Astrophysics Data System (ADS)

Maj, P.; Zdunek, J.; Mizera, J.; Kurzydlowski, K. J.; Sakowicz, B.; Kaminski, M.

2017-01-01

Serrated flow is a result of unstable plastic flow, which occurs during tensile and compression tests on some dilute alloys. This phenomenon is referred as the Portevin Le-Chatelier effect (PLC effect). The aim of this research was to investigate and analyze this phenomenon in Inconel 625 solution strengthened superalloy. The tested material was subjected to tensile tests carried out within the temperature range 200-700 °C, with three different strain rates: 0.002 1/s, 0.01/s, and 0.05 1/s and additional compression tests with high deformation speeds of 0.1, 1, and 10 1/s. The tensile strain curves were analyzed in terms of intensity and the observed patterns of serrations Using a modified stress drop method proposed by the authors, the activation energy was calculated with the assumption that the stress drops' distribution is a direct representation of an average solute atom's interaction with dislocations. Subsequently, two models, the standard vacancy diffusion Bilby-Cottrell model and the realistic cross-core diffusion mechanism proposed by Zhang and Curtin, were compared. The results obtained show that the second one agrees with the experimental data. Additional microstructure analysis was performed to identify microstructure elements that may be responsible for the PLC effect. Based on the results, the relationship between the intensity of the phenomenon and the conditions of the tests were determined.

Microgravity

NASA Image and Video Library

1995-04-06

An experiment vehicle plunges into the deceleration at the end of a 5.18-second drop in the Zero-Gravity Research Facility at NASA's Glenn Research Center. The Zero-Gravity Research Facility was developed to support microgravity research and development programs that investigate various physical sciences, materials, fluid physics, and combustion and processing systems. Payloads up to one-meter in diameter and 455 kg in weight can be accommodated. The facility has a 145-meter evacuated shaft to ensure a disturbance-free drop. This is No. 3 of a sequence of 4 images. (Credit: NASA/Glenn Research Center)

Microgravity

NASA Image and Video Library

1995-04-06

An experiment vehicle plunges into the deceleration pit at the end of a 5.18-second drop in the Zero-Gravity Research Facility at NASA's Glenn Research Center. The Zero-Gravity Research Facility was developed to support microgravity research and development programs that investigate various physical sciences, materials, fluid physcis, and combustion and processing systems. Payloads up to 1 meter in diameter and 455 kg in weight can be accommodated. The facility has a 145-meter evacuated shaft to ensure a disturbance-free drop. This is No. 2 of a sequence of 4 images. (Credit: NASA/Glenn Research Center)

Microgravity

NASA Image and Video Library

1995-04-06

An experiment vehicle plunges into the deceleration pit at the end of a 5.18-second drop in the Zero-Gravity Research Facility at NASA's Glenn Research Center. The Zero-Gravity Research Facility was developed to support microgravity research and development programs that investigate various physical sciences, materials, fluid physics, and combustion and processing systems. Payloads up to one meter in diameter and 455 kg in weight can be accommodated. The facility has a 145-meter evacuated shaft to ensure a disturbance-free drop. This is No. 4 of a sequence of 4 images. (Credit: NASA/Glenn Research Center)

Microgravity

NASA Image and Video Library

1995-04-06

An experiment vehicle plunges into the deceleration pit at the end of a 5.18-second drop in the Zero-Gravity Research Facility at NASA's Glenn Research Center. The Zero-Gravity Research Facility was developed to support microgravity research and development programs that investigate various physical sciences, materials, fluid physics, and combustion and processing systems. Payloads up to 1 meter in diameter and 455 kg in weight can be accommodated. The facility has a 145-meter evacuated shaft to ensure a disturbance-free drop. This is No.1 of a sequence of 4 images. (Credit: NASA/Glenn Research Center)

The Tower and Glass Marbles Problem

ERIC Educational Resources Information Center

Denman, Richard T.; Hailey, David; Rothenberg, Michael

2010-01-01

The Catseye Marble company tests the strength of its marbles by dropping them from various levels of their office tower, to find the highest floor from which a marble will not break. We find the smallest number of drops required and from which floor each drop should be made. We also find out how these answers change if a restriction is placed on…

An Auto-Tuning PI Control System for an Open-Circuit Low-Speed Wind Tunnel Designed for Greenhouse Technology.

PubMed

Espinoza, Karlos; Valera, Diego L; Torres, José A; López, Alejandro; Molina-Aiz, Francisco D

2015-08-12

Wind tunnels are a key experimental tool for the analysis of airflow parameters in many fields of application. Despite their great potential impact on agricultural research, few contributions have dealt with the development of automatic control systems for wind tunnels in the field of greenhouse technology. The objective of this paper is to present an automatic control system that provides precision and speed of measurement, as well as efficient data processing in low-speed wind tunnel experiments for greenhouse engineering applications. The system is based on an algorithm that identifies the system model and calculates the optimum PI controller. The validation of the system was performed on a cellulose evaporative cooling pad and on insect-proof screens to assess its response to perturbations. The control system provided an accuracy of <0.06 m·s(-1) for airflow speed and <0.50 Pa for pressure drop, thus permitting the reproducibility and standardization of the tests. The proposed control system also incorporates a fully-integrated software unit that manages the tests in terms of airflow speed and pressure drop set points.

A study of drop-off recycling in Norman, Oklahoma: Behavior of recyclers and nonrecyclers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sims, J.L.; Everett, J.W.

The reality of growing negative public opinion to new landfills prompted a newfound popularity for recycling programs as an alternative to traditional waste management in municipalities. The purpose of this research is to examine the behavioral and attitudinal differences between recyclers and nonrecyclers. These differences were tested statistically based on recycling behavior data gathered through two independent questionnaire surveys, one administered through utility bill statements, the other administered directly by the first author. Data were collected on: contact with the recycling organization, demographics, participation, convenience, incentives, ideological agreement, and assessment rationale. Seven hypotheses were tested, addressing most aspects of themore » Environmental Collective Action model (ECA), first proposed by the second author in 1994. The surveys were administered to City of Norman, Oklahoma residents. Norman operates several drop-off centers within the city limits. The results of the analysis indicate that individuals do make the decision to participate based on the principles outlined in the model of participation. All seven hypotheses are supported by the data in both surveys.« less

The crime drop in comparative perspective: the impact of the economy and imprisonment on American and European burglary rates.

PubMed

Rosenfeld, Richard; Messner, Steven F

2009-09-01

Influential statements on recent American crime reductions maintain that the crime drop was confined to the USA. Yet other research has revealed comparable crime decreases in Europe. We suggest that the USA and European crime declines occurred in tandem because they were both brought about by upturns in the economy. In light of US research showing crime reductions resulting from growth in imprisonment, we also examine the possibility that rising imprisonment rates reduced European crime rates. We test these hypotheses in a pooled cross-sectional time-series analysis of burglary rates in the USA and nine European nations between 1993 and 2006. The results indicate that burglary declines in the US and Europe were associated with rising consumer confidence. By contrast, imprisonment appears to be significantly related to burglary rates only after unusual policy interventions, such as Italy's 2006 clemency measure that dramatically reduced the size of its prison population. We interpret these findings as reflecting the structural similarity and economic integration of the world's developed nations and the uneven convergence in US and European punishment policies.

How Well Does the Theory of Planned Behavior Predict Graduation among College and University Students with Disabilities?

ERIC Educational Resources Information Center

Fichten, Catherine S.; Nguyen, Mai Nhu; Amsel, Rhonda; Jorgensen, Shirley; Budd, Jillian; Jorgensen, Mary; Asuncion, Jennison; Barile, Maria

2014-01-01

The goal of this research was to develop a model to predict which students with disabilities will drop out before graduation and to investigate the drop out pattern of students with disabilities. To accomplish this we evaluated potential predictors of persistence and drop-out among 611 college and university students with various disabilities and…

Labor Market Effects on Dropping out of High School: Variation by Gender, Race, and Employment Status

ERIC Educational Resources Information Center

McNeal, Ralph B., Jr.

2011-01-01

It is known from previous research that the likelihood of dropping out is affected by a number of individual traits, including, among others, socioeconomic status (SES), race/ethnicity, gender, and employment status. It is also known that dropping out is contingent on a variety of school characteristics. What is less known about is how dropping…

Comparison of atomization characteristics of drop-in and conventional jet fuels

NASA Astrophysics Data System (ADS)

Kannaiyan, Kumaran; Sadr, Reza; Micro Scale Thermo-Fluids Lab Team

2016-11-01

Surge in energy demand and stringent emission norms have been driving the interest on alternative drop-in fuels in aviation industry. The gas-to-liquid (GTL), synthetic paraffinic kerosene fuel derived from natural gas, has drawn significant attention as drop-in fuel due to its cleaner combustion characteristics when compared to other alternative fuels derived from various feedstocks. The fuel specifications such as chemical and physical properties of drop-in fuels are different from those of the conventional jet fuels, which can affect their atomization characteristics and in turn the combustion performance. The near nozzle liquid sheet dynamics of the drop-in fuel, GTL, is studied at different nozzle operating conditions and compared with that of the conventional Jet A-1 fuel. The statistical analysis of the near nozzle sheet dynamics shows that the drop-in fuel atomization characteristics are comparable to those of the conventional fuel. Furthermore, the microscopic spray characteristics measured using phase Doppler anemometry at downstream locations are slightly different between the fuels. Authors acknowledge the support by National Priorities Research Program (NPRP) of Qatar National Research Fund through the Grant NPRP-7-1449-2-523.

Jay L. King, Joseph D. Huxman, and Orion D. Billeter Assist Pilot Milt Thompson into the M2-F2 Attac

NASA Technical Reports Server (NTRS)

1966-01-01

NASA research pilot Milt Thompson is helped into the cockpit of the M2-F2 lifting body research aircraft at NASA's Flight Research Center (now the Dryden Flight Research Center). The M2-F2 is attached to a wing pylon under the wing of NASA's B-52 mothership. The flight was a captive flight with the pilot on-board. Milt Thompson flew in the lifting body throughout the flight, but it was never dropped from the mothership. NASA B-52, Tail Number 008, is an air launch carrier aircraft, 'mothership,' as well as a research aircraft platform that has been used on a variety of research projects. The aircraft, a 'B' model built in 1952 and first flown on June 11, 1955, is the oldest B-52 in flying status and has been used on some of the most significant research projects in aerospace history. Some of the significant projects supported by B-52 008 include the X-15, the lifting bodies, HiMAT (highly maneuverable aircraft technology), Pegasus, validation of parachute systems developed for the space shuttle program (solid-rocket-booster recovery system and the orbiter drag chute system), and the X-38. The B-52 served as the launch vehicle on 106 X-15 flights and flew a total of 159 captive-carry and launch missions in support of that program from June 1959 to October 1968. Information gained from the highly successful X-15 program contributed to the Mercury, Gemini, and Apollo human spaceflight programs as well as space shuttle development. Between 1966 and 1975, the B-52 served as the launch aircraft for 127 of the 144 wingless lifting body flights. In the 1970s and 1980s, the B-52 was the launch aircraft for several aircraft at what is now the Dryden Flight Research Center, Edwards, California, to study spin-stall, high-angle-of attack, and maneuvering characteristics. These included the 3/8-scale F-15/spin research vehicle (SRV), the HiMAT (Highly Maneuverable Aircraft Technology) research vehicle, and the DAST (drones for aerodynamic and structural testing). The aircraft supported the development of parachute recovery systems used to recover the space shuttle solid rocket booster casings. It also supported eight orbiter (space shuttle) drag chute tests in 1990. In addition, the B-52 served as the air launch platform for the first six Pegasus space boosters. During its many years of service, the B-52 has undergone several modifications. The first major modification was made by North American Aviation (now part of Boeing) in support of the X-15 program. This involved creating a launch-panel-operator station for monitoring the status of the test vehicle being carried, cutting a large notch in the right inboard wing flap to accommodate the vertical tail of the X-15 aircraft, and installing a wing pylon that enables the B-52 to carry research vehicles and test articles to be air-launched/dropped. Located on the right wing, between the inboard engine pylon and the fuselage, this wing pylon was subjected to extensive testing prior to its use. For each test vehicle the B-52 carried, minor changes were made to the launch-panel operator's station. Built originally by the Boeing Company, the NASA B-52 is powered by eight Pratt & Whitney J57-19 turbojet engines, each of which produce 12,000 pounds of thrust. The aircraft's normal launch speed has been Mach 0.8 (about 530 miles per hour) and its normal drop altitude has been 40,000 to 45,000 feet.. It is 156 feet long and has a wing span of 185 feet. The heaviest load it has carried was the No. 2 X-15 aircraft at 53,100 pounds. Project manager for the aircraft is Roy Bryant.

Development of a Smart Release Algorithm for Mid-Air Separation of Parachute Test Articles

NASA Technical Reports Server (NTRS)

Moore, James W.

2011-01-01

The Crew Exploration Vehicle Parachute Assembly System (CPAS) project is currently developing an autonomous method to separate a capsule-shaped parachute test vehicle from an air-drop platform for use in the test program to develop and validate the parachute system for the Orion spacecraft. The CPAS project seeks to perform air-drop tests of an Orion-like boilerplate capsule. Delivery of the boilerplate capsule to the test condition has proven to be a critical and complicated task. In the current concept, the boilerplate vehicle is extracted from an aircraft on top of a Type V pallet and then separated from the pallet in mid-air. The attitude of the vehicles at separation is critical to avoiding re-contact and successfully deploying the boilerplate into a heatshield-down orientation. Neither the pallet nor the boilerplate has an active control system. However, the attitude of the mated vehicle as a function of time is somewhat predictable. CPAS engineers have designed an avionics system to monitor the attitude of the mated vehicle as it is extracted from the aircraft and command a release when the desired conditions are met. The algorithm includes contingency capabilities designed to release the test vehicle before undesirable orientations occur. The algorithm was verified with simulation and ground testing. The pre-flight development and testing is discussed and limitations of ground testing are noted. The CPAS project performed a series of three drop tests as a proof-of-concept of the release technique. These tests helped to refine the attitude instrumentation and software algorithm to be used on future tests. The drop tests are described in detail and the evolution of the release system with each test is described.

Force-displacement differences in the lower extremities of young healthy adults between drop jumps and drop landings.

PubMed

Hackney, James M; Clay, Rachel L; James, Meredith

2016-10-01

We measured ground reaction force and lower extremity shortening in ten healthy, young adults in order to compare five trials of drop jumps to drop landings. Our dependent variable was the percentage of displacement (shortening) between the markers on the ASIS and second metatarsal heads on each LE, relative to the maximum shortening (100% displacement) for that trial at the point of greatest ground reaction force. We defined this as "percent displacement at maximum force" (%dFmax). The sample mean %dFmax was 0.73%±0.14% for the drop jumps, and 0.47%±0.09% for the drop landings. The mean within-subject difference score was 0.26%±0.20%. Two-tailed paired t test comparing %dFmax between the drop jump and drop landing yielded P=0.002. For all participants in this study, the %dFmax was greater in drop jumps than in drop landings. This indicates that in drop jumps, the point of maximum force and of maximum shortening was nearly simultaneous, compared to drop landings, where the point of maximum shortening followed that of maximum force by a greater proportion. This difference in force to displacement behavior is explained by linear spring behavior in drop jumps, and linear damping behavior in drop landings. Copyright © 2016 Elsevier B.V. All rights reserved.

Blast Mitigation Sea Analysis - Evaluation of Lumbar Compression Data Trends in 5th Percentile Female Anthropomorphic Test Device Performance Compared to 50th Percentile Male Anthropomorphic Test Device in Drop Tower Testing

DTIC Science & Technology

2016-08-21

less pronounced for pelvis velocity • Seat velocity and dynamic displacement not recorded for this test series – Would provide key information for...effectiveness of seat – Displacement /time history data should be recorded for all future test series UNCLASSIFIED UNCLASSIFIED Conclusions/Future...interfacing with seat manufacturers to broaden occupant protection range – Record dynamic stroke on all drop tower tests to evaluate correlation between displacement rate and lumbar compression UNCLASSIFIED UNCLASSIFIED 17

Experimental investigation of ice slurry flow pressure drop in horizontal tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grozdek, Marino; Khodabandeh, Rahmatollah; Lundqvist, Per

2009-01-15

Pressure drop behaviour of ice slurry based on ethanol-water mixture in circular horizontal tubes has been experimentally investigated. The secondary fluid was prepared by mixing ethyl alcohol and water to obtain initial alcohol concentration of 10.3% (initial freezing temperature -4.4 C). The pressure drop tests were conducted to cover laminar and slightly turbulent flow with ice mass fraction varying from 0% to 30% depending on test conditions. Results from flow tests reveal much higher pressure drop for higher ice concentrations and higher velocities in comparison to the single phase flow. However for ice concentrations of 15% and higher, certain velocitymore » exists at which ice slurry pressure drop is same or even lower than for single phase flow. It seems that higher ice concentration delay flow pattern transition moment (from laminar to turbulent) toward higher velocities. In addition experimental results for pressure drop were compared to the analytical results, based on Poiseulle and Buckingham-Reiner models for laminar flow, Blasius, Darby and Melson, Dodge and Metzner, Steffe and Tomita for turbulent region and general correlation of Kitanovski which is valid for both flow regimes. For laminar flow and low buoyancy numbers Buckingham-Reiner method gives good agreement with experimental results while for turbulent flow best fit is provided with Dodge-Metzner and Tomita methods. Furthermore, for transport purposes it has been shown that ice mass fraction of 20% offers best ratio of ice slurry transport capability and required pumping power. (author)« less

Significance of personality disorders in the face of drop-outs from psychiatric hospitalizations. The case of selected psychiatric units.

PubMed

Biała, Maja; Kiejna, Andrzej

2017-06-18

The World Health Organization's estimations indicate that about 50% of patients in well-developed countries may not adhere to long-term therapies. In the field of psychiatry, drop-outs from psychiatric treatment are particularly important. Personality disorders are a significant part of this sphere. The aim of this research was to empirically verify the hypothesis regarding the relation between comorbid personality disorders and drop-outs from treatment among patients of psychiatric wards. This study was a prospective cohort study. 110 patients, hospitalized in 3 different psychiatric wards, were included. Personality disorders were assessed with the Structured Clinical Interview For DSM-IV Personality Disorders (SCID-II). The research was financed by the Polish National Science Center (DEC-2011/01/N/NZ5/05364). The response rate was 89.1%. 72.56% of patients suffered from personality disorders (SCID-II) (among them the most prevalent were: personality disorder - not otherwise specified - 40.7% and borderline personality disorder - 12.38%; 22.95% of patients dropped out from treatment). However, occurrence of personality disorders was not relevant for those drop-outs. On the other hand, relationships at the level of certain criteria of borderline personality disorders and passive-aggressive personality have been revealed. These relationships became stronger when considered from the perspective of differences in the organization of treatment at individual wards. Some personality disorders may play an important role in drop-outs from psychiatric treatment. Presented results require further research.

Comparison of Personal, Social and Academic Variables Related to University Drop-out and Persistence.

PubMed

Bernardo, Ana; Esteban, María; Fernández, Estrella; Cervero, Antonio; Tuero, Ellián; Solano, Paula

2016-01-01

Dropping out of university has serious consequences not only for the student who drops out but also for the institution and society as a whole. Although this phenomenon has been widely studied, there is a need for broader knowledge of the context in which it occurs. Yet research on the subject often focuses on variables that, although they affect drop-out rates, lie beyond a university's control. This makes it hard to come up with effective preventive measures. That is why a northern Spanish university has undertaken a ex post facto holistic research study on 1,311 freshmen (2008/9, 2009/10, and 2010/11 cohorts). The study falls within the framework of the ALFA-GUIA European Project and focuses on those drop-out factors where there is scope for taking remedial measures. This research explored the possible relationship of degree drop-out and different categories of variables: variables related to the educational stage prior to university entry (path to entry university and main reason for degree choice), variables related to integration and coexistence at university (social integration, academic integration, relationships with teachers/peers and value of the living environment) financial status and performance during university studies (in terms of compliance with the program, time devoted to study, use of study techniques and class attendance). Descriptive, correlational and variance analyses were conducted to discover which of these variables really distinguish those students who drop-out from their peers who complete their studies. Results highlight the influence of vocation as main reason for degree choice, path to university entry, financial independency, social and academic adaptation, time devoted to study, use of study techniques and program compliance in the studied phenomenon.

Comparison of Personal, Social and Academic Variables Related to University Drop-out and Persistence

PubMed Central

Bernardo, Ana; Esteban, María; Fernández, Estrella; Cervero, Antonio; Tuero, Ellián; Solano, Paula

2016-01-01

Dropping out of university has serious consequences not only for the student who drops out but also for the institution and society as a whole. Although this phenomenon has been widely studied, there is a need for broader knowledge of the context in which it occurs. Yet research on the subject often focuses on variables that, although they affect drop-out rates, lie beyond a university’s control. This makes it hard to come up with effective preventive measures. That is why a northern Spanish university has undertaken a ex post facto holistic research study on 1,311 freshmen (2008/9, 2009/10, and 2010/11 cohorts). The study falls within the framework of the ALFA-GUIA European Project and focuses on those drop-out factors where there is scope for taking remedial measures. This research explored the possible relationship of degree drop-out and different categories of variables: variables related to the educational stage prior to university entry (path to entry university and main reason for degree choice), variables related to integration and coexistence at university (social integration, academic integration, relationships with teachers/peers and value of the living environment) financial status and performance during university studies (in terms of compliance with the program, time devoted to study, use of study techniques and class attendance). Descriptive, correlational and variance analyses were conducted to discover which of these variables really distinguish those students who drop-out from their peers who complete their studies. Results highlight the influence of vocation as main reason for degree choice, path to university entry, financial independency, social and academic adaptation, time devoted to study, use of study techniques and program compliance in the studied phenomenon. PMID:27803684

The impact performance of headguards for combat sports.

PubMed

McIntosh, Andrew S; Patton, Declan A

2015-09-01

To assess the impact energy attenuation performance of a range of headguards for combat sports. Seven headguards worn during combat sport training or competition, including two Association Internationale de Boxe Amateur (AIBA)-approved boxing models, were tested using drop tests. An International Organization for Standardization (ISO) rigid headform was used with a 5.6 kg drop assembly mass. Tests were conducted against a flat rigid anvil both with and without a boxing glove section. The centre forehead and lateral headguard areas were tested. Peak headform acceleration was measured. Tests from a selection of drop heights and repeated tests on the same headguard were conducted. Headguard performance varied by test condition. For the 0.4 m rigid anvil tests, the best model headguard was the thickest producing an average peak headform acceleration over 5 tests of 48 g compared with 456 g for the worst model. The mean peak acceleration for the 0.4, 0.5 and 0.6 frontal and lateral rigid anvil impact tests was between 32% and 40% lower for the Top Ten boxing model compared with the Adidas boxing model. The headguard performance deterioration observed with repeat impact against the flat anvil was reduced for impacts against the glove section. The overall reduction in acceleration for the combination of glove and headguard in comparison to the headguard condition was in the range of 72-93% for 0.6 and 0.8 m drop tests. The impact tests show the benefits of performance testing in identifying differences between headguard models. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

A drop in performance on a fluid intelligence test due to instructed-rule mindset.

PubMed

ErEl, Hadas; Meiran, Nachshon

2017-09-01

A 'mindset' is a configuration of processing resources that are made available for the task at hand as well as their suitable tuning for carrying it out. Of special interest, remote-relation abstract mindsets are introduced by activities sharing only general control processes with the task. To test the effect of a remote-relation mindset on performance on a Fluid Intelligence test (Raven's Advanced Progressive Matrices, RAPM), we induced a mindset associated with little usage of executive processing by requiring participants to execute a well-defined classification rule 12 times, a manipulation known from previous work to drastically impair rule-generation performance and associated cognitive processes. In Experiment 1, this manipulation led to a drop in RAPM performance equivalent to 10.1 IQ points. No drop was observed in a General Knowledge task. In Experiment 2, a similar drop in RAPM performance was observed (equivalent to 7.9 and 9.2 IQ points) regardless if participants were pre-informed about the upcoming RAPM test. These results indicate strong (most likely, transient) adverse effects of a remote-relation mindset on test performance. They imply that although the trait of Fluid Intelligence has probably not changed, mindsets can severely distort estimates of this trait.

Drop jumping. II. The influence of dropping height on the biomechanics of drop jumping.

PubMed

Bobbert, M F; Huijing, P A; van Ingen Schenau, G J

1987-08-01

In the literature, athletes preparing for explosive activities are recommended to include drop jumping in their training programs. For the execution of drop jumps, different techniques and different dropping heights can be used. This study was designed to investigate for the performance of bounce drop jumps the influence of dropping height on the biomechanics of the jumps. Six subjects executed bounce drop jumps from heights of 20 cm (designated here as DJ20), 40 cm (designated here as DJ40), and 60 cm (designated here as DJ60). During jumping, they were filmed, and ground reaction forces were recorded. The results of a biomechanical analysis show no difference between DJ20 and DJ40 in mechanical output about the joints during the push-off phase. Peak values of moment and power output about the ankles during the push-off phase were found to be smaller in DJ60 than in DJ40 (DJ20 = DJ60). The amplitude of joint reaction forces increased with dropping height. During DJ60, the net joint reaction forces showed a sharp peak on the instant that the heels came down on the ground. Based on the results, researchers are advised to limit dropping height to 20 or 40 cm when investigating training effects of the execution of bounce drop jumps.

A comparison of cognitive skills between completes and dropouts in a college physics course

NASA Astrophysics Data System (ADS)

Hudson, H. T.

Separate tests of mathematics skills, proportions and translations between words, and mathematical expression given the first week of class were correlated with performance for students who completed a college physics course (completes) and students who dropped the course (drops). None of the measures used discriminated between completes and drops as groups. However, the correlations between score on the test of math skills and on both of the measures involving mathematical reasoning (proportions, and translations) were dramatically different for the two groups. For the completes, these correlations were slightly negative, but not significant. For the drops, the correlation was positive and signficant at the p < 0.01 level. This suggests the possibility that the students who complete the course tend to have independent cognitive skills for the mechanical mathematical operations and for questions requiring some degree of reasoning, while, in contrast, the same skills for students at high risk for dropping overlap significantly. The study also found that when students are given the results of mathematics skills tests in a diagnostic mode, with feedback on specific areas of weakness and time to remediate with self study, the correlation between mathematics and physics is lower than previously reported values.Received: 2 April 1985

Temporal sequencing of throughfall drop generation as revealed by use of a large-scale rainfall simulator

NASA Astrophysics Data System (ADS)

Nanko, K.; Levia, D. F., Jr.; Iida, S.; SUN, X.; Shinohara, Y.; Sakai, N.

2017-12-01

Scientists have been interested in throughfall drop size and its distribution because of its importance to soil erosion and the forest water balance. An indoor experiment was employed to deepen our understanding of throughfall drop generation processes to promote better management of forested ecosystems. The indoor experiment provides a unique opportunity to examine an array of constant rainfall intensities that are ideal conditions to pick up the effect of changing intensities and not found in the fields. Throughfall drop generation was examined for three species- Cryptomeria japonica D. Don (Japanese cedar), Chamaecyparis obtusa (Siebold & Zucc.) Endl. (Japanese cypress), and Zelkova serrata Thunb. (Japanese zelkova)- under both leafed and leafless conditions in the large-scale rainfall simulator in the National Research Institute for Earth Science and Disaster Resilience (Tsukuba, Japan) at varying rainfall intensities ranging from15 to 100 mm h-1. Drop size distributions of the applied rainfall and throughfall were measured simultaneously by 20 laser disdrometers. Utilizing the drop size dataset, throughfall was separated into three components: free throughfall, canopy drip, and splash throughfall. The temporal sequencing of the throughfall components were analyzed on a 1-min interval during each experimental run. The throughfall component percentage and drop size of canopy drip differed among tree species and rainfall intensities and by elapsed time from the beginning of the rainfall event. Preliminary analysis revealed that the time differences to produce branch drip as compared to leaf (or needle) drip was partly due to differential canopy wet-up processes and the disappearance of branch drips due to canopy saturation, leading to dissimilar throughfall drop size distributions beneath the various tree species examined. This research was supported by JSPS Invitation Fellowship for Research in Japan (Grant No.: S16088) and JSPS KAKENHI (Grant No.: JP15H05626).

Mineback Stimulation Research Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warpinski, N.R.

The Mineback Stimulation Research Program is a systematic study of hydraulic fracturing and the parameters which influence or control fracture geometry or behavior. Fractures are created near a tunnel complex at DOE's Nevada Test Site and are monitored, instrumented, and mined back to observe the effect of treatment, rock and reservoir properties on the fractures. An initial experiment to measure width and pressure in a hydraulic fracture was completed in FY 1983. The test showed that pressure drops along fractures are much larger than predicted, with the result that fractures are shorter, higher, and wider than present models estimate. Themore » cause of this is the complex morphology of hydraulic fractures, including a hierarchy of roughnesses, multiple stranding, and corners, such as the offsets which occur when natural fractures are intersected. A test to study flow behavior in hydraulic fractures with proppant is proposed for FY 1984. 7 figures.« less

Seismic imaging of post-glacial sediments - test study before Spitsbergen expedition

NASA Astrophysics Data System (ADS)

Szalas, Joanna; Grzyb, Jaroslaw; Majdanski, Mariusz

2017-04-01

This work presents results of the analysis of reflection seismic data acquired from testing area in central Poland. For this experiment we used total number of 147 vertical component seismic stations (DATA-CUBE and Reftek "Texan") with accelerated weight drop (PEG-40). The profile was 350 metres long. It is a part of pilot study for future research project on Spitsbergen. The purpose of the study is to recognise the characteristics of seismic response of post-glacial sediments in order to design the most adequate survey acquisition parameters and processing sequence for data from Spitsbergen. Multiple tests and comparisons have been performed to obtain the best possible quality of seismic image. In this research we examine the influence of receiver interval size, front mute application and surface wave attenuation attempts. Although seismic imaging is the main technique we are planning to support this analysis with additional data from traveltime tomography, MASW and other a priori information.

Dropping In a Microgravity Environment (DIME) contest

NASA Technical Reports Server (NTRS)

2001-01-01

The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. NASA and contractor personnel who conducted the DIME activity with the students. Shown (L-R) are: Eric Baumann (NASA, 2.2-second Drop Tower Facility manager), Daniel Dietrich (NASA) mentor for Sycamore High School team), Carol Hodanbosi (National Center for Microgravity Research; DIME staff), Richard DeLombard (NASA; DIME staff), Jose Carrion (GRC Akima, drop tower technician), Dennis Stocker (NASA; DIME staff), Peter Sunderland (NCMR, mentor for COSI Academy student team), Sandi Thompson (NSMR sabbatical teacher; DIME staff), Dan Woodard (MASA Microgravity Outreach Program Manager), Adam Malcolm (NASA co-op student; DIME staff), Carla Rosenberg (NCMR; DIME staff), and Twila Schneider (Infinity Technology; NASA Microgravity Research program contractor). This image is from a digital still camera; higher resolution is not available.

The Oil Drop Experiment: An Illustration of Scientific Research Methodology and its Implications for Physics Textbooks

ERIC Educational Resources Information Center

Rodriguez, Maria A.; Niaz, Mansoor

2004-01-01

The objectives of this study are: (1) evaluation of the methodology used in recent search for particles with fractional electrical charge (quarks) and its implications for understanding the scientific research methodology of Millikan; (2) evaluation of 43 general physics textbooks and 11 laboratory manuals, with respect to the oil drop experiment,…

Extrapolating the Trends of Test Drop Data with Opening Shock Factor Calculations: the Case of the Orion Main and Drogue Parachutes Inflating to 1st Reefed Stage

NASA Technical Reports Server (NTRS)

Potvin, Jean; Ray, Eric

2017-01-01

We describe a new calculation of the opening shock factor C (sub k) characterizing the inflation performance of NASA's Orion spacecraft main and drogue parachutes opening under a reefing constraint (1st stage reefing), as currently tested in the Capsule Parachute Assembly System (CPAS) program. This calculation is based on an application of the Momentum-Impulse Theorem at low mass ratio (R (sub m) is less than 10 (sup -1)) and on an earlier analysis of the opening performance of drogues decelerating point masses and inflating along horizontal trajectories. Herein we extend the reach of the Theorem to include the effects of payload drag and gravitational impulse during near-vertical motion - both important pre-requisites for CPAS parachute analysis. The result is a family of C (sub k) versus R (sub m) curves which can be used for extrapolating beyond the drop-tested envelope. The paper proves this claim in the case of the CPAS Mains and Drogues opening while trailing either a Parachute Compartment Drop Test Vehicle or a Parachute Test Vehicle (an Orion capsule boiler plate). It is seen that in all cases the values of the opening shock factor can be extrapolated over a range in mass ratio that is at least twice that of the test drop data.

A microcontroller platform for the rapid prototyping of functional electrical stimulation-based gait neuroprostheses.

PubMed

Luzio de Melo, Paulo; da Silva, Miguel Tavares; Martins, Jorge; Newman, Dava

2015-05-01

Functional electrical stimulation (FES) has been used over the last decades as a method to rehabilitate lost motor functions of individuals with spinal cord injury, multiple sclerosis, and post-stroke hemiparesis. Within this field, researchers in need of developing FES-based control solutions for specific disabilities often have to choose between either the acquisition and integration of high-performance industry-level systems, which are rather expensive and hardly portable, or develop custom-made portable solutions, which despite their lower cost, usually require expert-level electronic skills. Here, a flexible low-cost microcontroller-based platform for rapid prototyping of FES neuroprostheses is presented, designed for reduced execution complexity, development time, and production cost. For this reason, the Arduino open-source microcontroller platform was used, together with off-the-shelf components whenever possible. The developed system enables the rapid deployment of portable FES-based gait neuroprostheses, being flexible enough to allow simple open-loop strategies but also more complex closed-loop solutions. The system is based on a modular architecture that allows the development of optimized solutions depending on the desired FES applications, even though the design and testing of the platform were focused toward drop foot correction. The flexibility of the system was demonstrated using two algorithms targeting drop foot condition within different experimental setups. Successful bench testing of the device in healthy subjects demonstrated these neuroprosthesis platform capabilities to correct drop foot. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Adaptation of a 15-ft-dia ribbon parachute and a 73-ft cross main recovery parachute for cargo delivery from high altitude

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pepper, W.B.; Lucero, H.; Klimas, P.C.

1984-01-01

An existing parachute system has been adapted for delivery of a resupply container at high altitudes from aircraft. The parachute system consists of a 15-ft diameter ribbon parachute reefed for 10 seconds and a 73-ft diameter cross parachute reefed for 10 seconds. A solid state recorder in the 2341 1b drop test vehicle was used to obtain deceleration history with time. Two drop tests using the Navy A7 aircraft were conducted at Stallion Site, White Sands Missile Range, New Mexico. Drop release conditions were 250 KCAS at 20,000 ft above sea level from the first test and 230 KCAS atmore » 22,000 ft msl for the second. A new load transfer bridle was designed and tested to release the first stage parachute and replace a costly mechanical load plate.« less

Development and Validation of the Delinquency Reduction Outcome Profile (DROP) in a Sample of Incarcerated Juveniles: A Multiconstruct/Multisituational Scoring Approach

ERIC Educational Resources Information Center

Barbot, Baptiste; Haeffel, Gerald J.; Macomber, Donna; Hart, Lesley; Chapman, John; Grigorenko, Elena L.

2012-01-01

The "Delinquency Reduction Outcome Profile" ("DROP") is a novel situational-judgment test (SJT) designed to measure social decision making in delinquent youth. The DROP includes both a typical SJT scoring method, which captures the deviation of an individual response from an "ideal" expert-based response pattern, as well as a novel…

Coefficient of restitution of sports balls: A normal drop test

NASA Astrophysics Data System (ADS)

Haron, Adli; Ismail, K. A.

2012-09-01

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

Additional Results of Glaze Icing Scaling in SLD Conditions

NASA Technical Reports Server (NTRS)

Tsao, Jen-Ching

2016-01-01

New guidance of acceptable means of compliance with the super-cooled large drops (SLD) conditions has been issued by the U.S. Department of Transportation's Federal Aviation Administration (FAA) in its Advisory Circular AC 25-28 in November 2014. The Part 25, Appendix O is developed to define a representative icing environment for super-cooled large drops. Super-cooled large drops, which include freezing drizzle and freezing rain conditions, are not included in Appendix C. This paper reports results from recent glaze icing scaling tests conducted in NASA Glenn Icing Research Tunnel (IRT) to evaluate how well the scaling methods recommended for Appendix C conditions might apply to SLD conditions. The models were straight NACA 0012 wing sections. The reference model had a chord of 72 inches and the scale model had a chord of 21 inches. Reference tests were run with airspeeds of 100 and 130.3 knots and with MVD's of 85 and 170 microns. Two scaling methods were considered. One was based on the modified Ruff method with scale velocity found by matching the Weber number W (sub eL). The other was proposed and developed by Feo specifically for strong glaze icing conditions, in which the scale liquid water content and velocity were found by matching reference and scale values of the non-dimensional water-film thickness expression and the film Weber number W (sub ef). All tests were conducted at 0 degrees angle of arrival. Results will be presented for stagnation freezing fractions of 0.2 and 0.3. For non-dimensional reference and scale ice shape comparison, a new post-scanning ice shape digitization procedure was developed for extracting 2-dimensional ice shape profiles at any selected span-wise location from the high fidelity 3-dimensional scanned ice shapes obtained in the IRT.

Additional Results of Glaze Icing Scaling in SLD Conditions

NASA Technical Reports Server (NTRS)

Tsao, Jen-Ching

2016-01-01

New guidance of acceptable means of compliance with the super-cooled large drops (SLD) conditions has been issued by the U.S. Department of Transportation's Federal Aviation Administration (FAA) in its Advisory Circular AC 25-28 in November 2014. The Part 25, Appendix O is developed to define a representative icing environment for super-cooled large drops. Super-cooled large drops, which include freezing drizzle and freezing rain conditions, are not included in Appendix C. This paper reports results from recent glaze icing scaling tests conducted in NASA Glenn Icing Research Tunnel (IRT) to evaluate how well the scaling methods recommended for Appendix C conditions might apply to SLD conditions. The models were straight NACA 0012 wing sections. The reference model had a chord of 72 in. and the scale model had a chord of 21 in. Reference tests were run with airspeeds of 100 and 130.3 kn and with MVD's of 85 and 170 micron. Two scaling methods were considered. One was based on the modified Ruff method with scale velocity found by matching the Weber number WeL. The other was proposed and developed by Feo specifically for strong glaze icing conditions, in which the scale liquid water content and velocity were found by matching reference and scale values of the nondimensional water-film thickness expression and the film Weber number Wef. All tests were conducted at 0 deg AOA. Results will be presented for stagnation freezing fractions of 0.2 and 0.3. For nondimensional reference and scale ice shape comparison, a new post-scanning ice shape digitization procedure was developed for extracting 2-D ice shape profiles at any selected span-wise location from the high fidelity 3-D scanned ice shapes obtained in the IRT.

Accomplishments of the Abrupt Wing Stall (AWS) Program and Future Research Requirements

NASA Technical Reports Server (NTRS)

Hall, Robert M.; Woodson, Shawn H.; Chambers, Joseph R.

2003-01-01

The Abrupt Wing Stall (AWS) Program has addressed the problem of uncommanded lateral motions, such as wing drop and wing rock, at transonic speeds. The genesis of this Program was the experience of the F/A-1 8E/F Program in the late 1990's, when wing drop was discovered in the heart of the maneuver envelope for the pre-production aircraft. While the F/A-1 8E/F problem was subsequently corrected by a leading-edge flap scheduling change and the addition of a porous door to the wing fold fairing, the AWS Program was initiated as a national response to the lack of technology readiness available at the time of the F/A-18E/F Development Program. The AWS Program objectives were to define causal factors for the F/A-18E/F experience, to gain insights into the flow physics associated with wing drop, and to develop methods and analytical tools so that future programs could identify this type of problem before going to flight test. The paper reviews, for the major goals of the AWS Program, the status of the technology before the

Cut your losses: self-amputation of injured limbs increases survival.

PubMed

Emberts, Zachary; Miller, Christine W; Kiehl, Daniel; St Mary, Colette M

2017-01-01

Autotomy, self-induced limb loss, is an extreme trait observed throughout the animal kingdom; lizards drop their tails, crickets release their legs, and crabs drop their claws. These repeated evolutionary origins suggest that autotomy is adaptive. Yet, we do not have a firm understanding of the selective pressures that promote and maintain this extreme trait. Although multiple adaptive hypotheses exist, research has generally focused on autotomy's adaptive value as a form of predator escape. However, autotomy could also be selected to reduce the cost of an injured limb, which we investigate here. Previously, this alternative hypothesis has been challenging to directly test because when an injury occurs on an autotomizable limb, that limb is almost always dropped (i.e., autotomy is behaviorally fixed within populations). Recently, however, we have identified a species, Narnia femorata (Insecta: Hemiptera: Coreidae), where some individuals autotomize limbs in response to injury, but some do not. This natural variation allowed us to investigate both the survival costs of retaining an injured limb and the benefits of autotomizing it. In this study, we find a positive association between autotomizing injured limbs and survival, thereby quantifying a new and likely widespread benefit of autotomy-reducing the cost of injury.

Cut your losses: self-amputation of injured limbs increases survival

PubMed Central

Miller, Christine W; Kiehl, Daniel; St. Mary, Colette M

2017-01-01

Abstract Autotomy, self-induced limb loss, is an extreme trait observed throughout the animal kingdom; lizards drop their tails, crickets release their legs, and crabs drop their claws. These repeated evolutionary origins suggest that autotomy is adaptive. Yet, we do not have a firm understanding of the selective pressures that promote and maintain this extreme trait. Although multiple adaptive hypotheses exist, research has generally focused on autotomy’s adaptive value as a form of predator escape. However, autotomy could also be selected to reduce the cost of an injured limb, which we investigate here. Previously, this alternative hypothesis has been challenging to directly test because when an injury occurs on an autotomizable limb, that limb is almost always dropped (i.e., autotomy is behaviorally fixed within populations). Recently, however, we have identified a species, Narnia femorata (Insecta: Hemiptera: Coreidae), where some individuals autotomize limbs in response to injury, but some do not. This natural variation allowed us to investigate both the survival costs of retaining an injured limb and the benefits of autotomizing it. In this study, we find a positive association between autotomizing injured limbs and survival, thereby quantifying a new and likely widespread benefit of autotomy—reducing the cost of injury. PMID:29622925

An Automatic Drag-and-Drop Assistive Program Developed to Assistive People with Developmental Disabilities to Improve Drag-and-Drop Efficiency

ERIC Educational Resources Information Center

Shih, Ching-Hsiang; Huang, Hsun-Chin; Liao, Yung-Kun; Shih, Ching-Tien; Chiang, Ming-Shan

2010-01-01

The latest researches adopted software technology to improve pointing performance; however, Drag-and-Drop (DnD) operation is also commonly used in modern GUI programming. This study evaluated whether two children with developmental disabilities would be able to improve their DnD performance, through an Automatic DnD Assistive Program (ADnDAP). At…

Drop Tower Workshop

NASA Technical Reports Server (NTRS)

Urban, David

2013-01-01

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

Typology of School Dropout: The Dimensions and Dynamics of Dropout in Ghana

ERIC Educational Resources Information Center

Ananga, Eric Daniel

2011-01-01

This paper explores the dropout experience of children who dropped out of schools located in two rural communities in the Central Region of Ghana. The main research question sought to explore the meaning and types of drop out founded on the views of children who had dropped out of school. The study tracked 18 children aged 7-17 years. Snowball…

A study of pressure losses in residential air distribution systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abushakra, Bass; Walker, Iain S.; Sherman, Max H.

2002-07-01

An experimental study was conducted to evaluate the pressure drop characteristics of residential duct system components that are either not available or not thoroughly (sometimes incorrectly) described in existing duct design literature. The tests were designed to imitate cases normally found in typical residential and light commercial installations. The study included three different sizes of flexible ducts, under different compression configurations, splitter boxes, supply boots, and a fresh air intake hood. The experimental tests conformed to ASHRAE Standard 120P--''Methods of Testing to Determine Flow Resistance of HVAC Air Ducts and Fittings''. The flexible duct study covered compressibility and bending effectsmore » on the total pressure drop, and the results showed that the available published references tend to underestimate the effects of compression in flexible ducts that can increase pressure drops by up to a factor of nine. The supply boots were tested under different configurations including a setup where a flexible duct elbow connection was considered as an integral part of the supply boot. The supply boots results showed that diffusers can increase the pressure drop by up to a factor of two in exit fittings, and the installation configuration can increase the pressure drop by up to a factor of five. The results showed that it is crucial for designers and contractors to be aware of the compressibility effects of the flexible duct, and the installation of supply boots and diffusers.« less

Fundamentals of Mold Free Casting: Experimental and Computational Studies

NASA Technical Reports Server (NTRS)

Tryggvason, Gretar; Ceccio, Steven

1997-01-01

Researchers are developing the technology of 'Ballistic Particle Manufacturing' (BPM) in which individual drops are precisely layered onto a substrate, and the drops are deposited so as to prevent splatting. These individual drops will ultimately be combined to form a net-shape, three-dimensional object. Our understanding of controlled drop deposition as applied to BPM is far from complete. Process parameters include the size and temperature of the liquid metal drop, its impact velocity and trajectory, and the condition and temperature of the substrate. Quantitative knowledge of the fluid mechanics and heat transfer of drop deposition and solidification are necessary to fully optimize the manufacturing process and to control the material microstructure of the final part. The object of this study is to examine the dynamics of liquid metal drops as they impinge upon a solid surface and solidify under conditions consistent with BPM (i.e. conditions which produce non-splatting drops). A program of both numerical simulations and experiments will be conducted. Questions this study will address include the following: How do the deformation and solidification of the drop depend on the properties of the fluid drop and the solid substrate? How does the presence of previously deposited drops affect the impingement and solidification process? How does the impingement of the new drop affect already deposited material? How does the cooling rate and solidification of the drops influence the material microstructure?

Visualization Measurement of Streaming Flows Associated with a Single-Acoustic Levitator

NASA Astrophysics Data System (ADS)

Hasegawa, Koji; Abe, Yutaka; Kaneko, Akiko; Yamamoto, Yuji; Aoki, Kazuyoshi

2009-08-01

The purpose of the study is to experimentally investigate flow fields generated by an acoustic levitator. This flow field has been observed using flow visualization, PIV method. In the absent of a drop, the flow field was strongly influenced by sound pressure level (SPL). In light of the interfacial stability of a levitated drop, SPL was set at 161-163 [dB] in our experiments. In the case of any levitated drop at a pressure node of a standing wave, the toroidal vortices were appeared around a drop and clearly observed the flow fields around the drop by PIV measurement. It is found that the toroidal vortices around a levitated drop were strongly affected by the viscosity of a drop. For more detailed research, experiments in the reduced gravity were conducted with aircraft parabolic flights. By comparison with experimental results in the earth and reduced gravity, it is also indicated that the configuration of the external flow field around a drop is most likely to be affected by a position of a drop as well.

Integration of three echelon supply chain (supplier-manufacturer-distributor-drop shipper) with permissible delay in payment and penalty contract

NASA Astrophysics Data System (ADS)

Ibrahim, M. F.; Suparno

2018-04-01

Supply Chain Management (SCM) has to be considered in the company in order to improve the sustainability and competitiveness. SCM executed to integrating any companies on the supply chain in a way of coordinating the flow of goods, information, and financial. Permissible delay in payment is one of the coordination ways with allowing the costumers delay the payments to a vendor in some certain periods without any interest charges. In the supply chain system, drop-shipping player already familiar in this era. In drop-shipping internet retailing, the supplier will hold supplies and also carry out physical distribution service on behalf of drop-shipper. Drop-shipper will just focus on selling, on the other hand, their supplier will be responsible for the physical process. Generally, drop-shipper have information of the customer demands better than the distributor. But, it is also unrare when the drop-shipper send the estimation of demands which bigger than their own estimation in order to maximize their own interest, so they hope supplies of the distributor will always enough to accommodate their demands. Contributions in this research will be focused on integration of three echelons supply chain, which are the supplier, manufacturer, distributor, and drop-shipper. With considering delay in payment on first and second echelons, and also the contract penalty on third echelon. The problem on this research will be modeled in some kind of cases which can represent the problem of real supply chain system. Sensitivity analysis will be done on certain significant variables toward the changes of total supply chain cost. Coordination with delay in payment success to integrate supply chain. Contract penalty plan success to maintain the profit of distributor and drop-shipper.

NASA Glenn Icing Research Tunnel: 2014 Cloud Calibration Procedure and Results

NASA Technical Reports Server (NTRS)

Van Zante, Judith F.; Ide, Robert F.; Steen, Laura E.; Acosta, Waldo J.

2014-01-01

The results of the December 2013 to February 2014 Icing Research Tunnel full icing cloud calibration are presented. The calibration steps included establishing a uniform cloud and conducting drop size and liquid water content calibrations. The goal of the calibration was to develop a uniform cloud, and to generate a transfer function from the inputs of air speed, spray bar atomizing air pressure and water pressure to the outputs of median volumetric drop diameter and liquid water content. This was done for both 14 CFR Parts 25 and 29, Appendix C ('typical' icing) and soon-to-be released Appendix O (supercooled large drop) conditions.

Objective Evaluation of Vergence Disorders and a Research-Based Novel Method for Vergence Rehabilitation

PubMed Central

Kapoula, Zoï; Morize, Aurélien; Daniel, François; Jonqua, Fabienne; Orssaud, Christophe; Brémond-Gignac, Dominique

2016-01-01

Purpose We performed video-oculography to evaluate vergence eye movement abnormalities in students diagnosed clinically with vergence disorders. We tested the efficiency of a novel rehabilitation method and evaluated its benefits with video-oculography cross-correlated with clinical tests and symptomatology. Methods A total of 19 students (20–27 years old) underwent ophthalmologic, orthoptic examination, and a vergence test coupled with video-oculography. Eight patients were diagnosed with vergence disorders with a high symptomatology score (CISS) and performed a 5-week session of vergence rehabilitation. Vergence and rehabilitation tasks were performed with a trapezoid surface of light emitting diodes (LEDs) and adjacent buzzers (US 8851669). We used a novel Vergence double-step (Vd-s) protocol: the target stepped to a second position before the vergence movement completion. Afterward the vergence test was repeated 1 week and 1 month later. Results Abnormally increased intertrial variability was observed for many vergence parameters (gain, duration, and speed) for the subjects with vergence disorders. High CISS scores were correlated with variability and increased latency. After the Vd-s, variability of all parameters dropped to normal or better levels. Moreover, the convergence and divergence latency diminished significantly to levels better than normal; benefits were maintained 1 month after completion of Vd-s. CISS scores dropped to normal level, which was maintained up to 1 year. Conclusions and Translational Relevance: Intertrial variability is the major marker of vergence disorders. The Vd-s research-based method leads to normalization of vergence properties and lasting removal of symptoms. The efficiency of the method is due to the spatiotemporal parameters of repetitive trials that stimulate neural plasticity. PMID:26981330

Use of clinical movement screening tests to predict injury in sport

PubMed Central

Chimera, Nicole J; Warren, Meghan

2016-01-01

Clinical movement screening tests are gaining popularity as a means to determine injury risk and to implement training programs to prevent sport injury. While these screens are being used readily in the clinical field, it is only recently that some of these have started to gain attention from a research perspective. This limits applicability and poses questions to the validity, and in some cases the reliability, of the clinical movement tests as they relate to injury prediction, intervention, and prevention. This editorial will review the following clinical movement screening tests: Functional Movement Screen™, Star Excursion Balance Test, Y Balance Test, Drop Jump Screening Test, Landing Error Scoring System, and the Tuck Jump Analysis in regards to test administration, reliability, validity, factors that affect test performance, intervention programs, and usefulness for injury prediction. It is important to review the aforementioned factors for each of these clinical screening tests as this may help clinicians interpret the current body of literature. While each of these screening tests were developed by clinicians based on what appears to be clinical practice, this paper brings to light that this is a need for collaboration between clinicians and researchers to ensure validity of clinically meaningful tests so that they are used appropriately in future clinical practice. Further, this editorial may help to identify where the research is lacking and, thus, drive future research questions in regards to applicability and appropriateness of clinical movement screening tools. PMID:27114928

Passive Earth Entry Vehicle Landing Test

NASA Technical Reports Server (NTRS)

Kellas, Sotiris

2017-01-01

Two full-scale passive Earth Entry Vehicles (EEV) with realistic structure, surrogate sample container, and surrogate Thermal Protection System (TPS) were built at NASA Langley Research Center (LaRC) and tested at the Utah Test and Training Range (UTTR). The main test objective was to demonstrate structural integrity and investigate possible impact response deviations of the realistic vehicle as compared to rigid penetrometer responses. With the exception of the surrogate TPS and minor structural differences in the back shell construction, the two test vehicles were identical in geometry and both utilized the Integrated Composite Stiffener Structure (ICoSS) structural concept in the forward shell. The ICoSS concept is a lightweight and highly adaptable composite concept developed at NASA LaRC specifically for entry vehicle TPS carrier structures. The instrumented test vehicles were released from a helicopter approximately 400 m above ground. The drop height was selected such that at least 98% of the vehicles terminal velocity would be achieved. While drop tests of spherical penetrometers and a low fidelity aerodynamic EEV model were conducted at UTTR in 1998 and 2000, this was the first time a passive EEV with flight-like structure, surrogate TPS, and sample container was tested at UTTR for the purpose of complete structural system validation. Test results showed that at a landing vertical speed of approximately 30 m/s, the test vehicle maintained structural integrity and enough rigidity to penetrate the sandy clay surface thus attenuating the landing load, as measured at the vehicle CG, to less than 600 g. This measured deceleration was found to be in family with rigid penetrometer test data from the 1998 and 2000 test campaigns. Design implications of vehicle structure/soil interaction with respect to sample container and sample survivability are briefly discussed.

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

NASA Technical Reports Server (NTRS)

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

2010-01-01

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

Affordable Acoustic Disdrometer: Design, Calibration, Tests

NASA Astrophysics Data System (ADS)

van de Giesen, N.; Degen, C.; Hut, R.

2009-12-01

It would be a hydrological understatement to say that measuring rainfall correctly is important. Recent years have seen important lowering of the costs of raingauges capable of measuring rainfall intensities. Such raingauges are typically tipping bucket raingauges, connected to an event logger. Costs for such a raingauge are about 100. Accuracy is not always very high, especially during high intensity storms. The moving parts make them vulnerable to slight disruptions such as insects. We set out to design a raingauge without moving parts and at a better price/quality ratio than existing raingauges. After testing several potential candidates, we settled on a very simple piezo ceramic element, which measures the impact of single drops. Such an element costs around 1. The impact of each drop causes an acoustic signal that is transformed into a voltage. A typical impact gives an upswing of up to 1 V and the ringing lasts about 50 ms. With a surface area of about 20 cm2, there is almost never overlap between the signals of different drops. The basic assumption is that each drop will have reached terminal velocity and that the total energy of the impact can, thereby, be related to drop size. We calibrated this acoustic disdrometer by letting drops of different size fall on the disdrometer. A very encouraging calibration curve was obtained in this way. Further testing consisted of comparisons during rainstorms between the acoustic disdrometer and standard tipping bucket raingauges. During intensive storms, the acoustic disdrometer gave results that were very close to those of a nearby totaling raingauge. The signal of the tipping bucket raingauges was clearly saturated as these were not capable of keeping up with the rain. During low intensity events, tipping bucket raingauges performed better as drops too small to detect by the acoustic disdrometer became a significant part of the total rainfall. In first instance, a simple MP3 player with recording functionality ($50) was used as datalogger and processing was performed with a Matlab script. Presently, processing is done on-board of a simple custom built logger that logs the time and total energy of each drop. Post-processing converts the total energy to drop size and corrects for missing small drops by fitting the pdf’s to known raindrop distributions.

Identifying potential dropouts from college physics classes

NASA Astrophysics Data System (ADS)

Wollman, Warren; Lawrenz, Frances

Hudson and Rottman (1981) established that mathematics ability is probably a secondary factor influencing dropout from college physics courses. Other factors remain to be found for predicting who will drop out or at least have difficulty with the course. When mathematics ability is coupled with general indicators of performance (total GPA and ACT natural science), prediction of performance for those who complete the course is substantially improved. Moreover, discriminant analyses reveal who will have at least some difficulty, but not who will drop out. The problem of isolating specific weaknesses of students who have difficulty persists. Physics achievement appears to depend on mathematics ability only to the extent that students possess the ability to utilize mathematics knowledge for solving physics problems. Identification of the specific aspects of this ability as well as the specific deficiencies leading to dropout should be the object of future research. For the present, interviews might be more revealing than group testing methods.

Metals combustion in normal gravity and microgravity

NASA Technical Reports Server (NTRS)

Steinberg, Theodore A.; Wilson, D. Bruce; Benz, Frank J.

1993-01-01

The study of the combustion characteristics of metallic materials has been an ongoing area of research at the NASA White Sands Test Facility (WSTF). This research has been in support of both government and industrial operations and deals not only with the combustion of specific metallic materials but also with the relative flammabilities of these materials under similar conditions. Since many of the metallic materials that are characterized at WSTF for aerospace applications are to be used in microgravity environments, it was apparent that the testing of these materials needed to proceed in a microgravity environment. It was believed that burning metallic materials in a microgravity environment would allow the evaluation of the validity of applying normal gravity combustion tests to characterize metallic materials to be used in microgravity environments. It was also anticipated that microgravity testing would provide insight into the general combustion process of metallic materials. The availability of the NASA Lewis Research Center's (LeRC) 2.2-second drop tower provided the necessary facility to accomplish the microgravity portion of the testing while the normal gravity testing was conducted at NASA WSTF. The tests, both at LeRC and WSTF, were conducted in the same instrumented system and utilized the standard metal flammability test of upward propagation burning of cylindrical rod samples.

Evaluation of wheelchair seating system crashworthiness: "drop hook"-type seat attachment hardware.

PubMed

Bertocci, G; Ha, D; Deemer, E; Karg, P

2001-04-01

To evaluate the crashworthiness of commercially available hardware that attaches seat surfaces to the wheelchair frame. A low cost static crashworthiness test procedure that simulates a frontal impact motor vehicle crash. Safety testing laboratory. Eleven unique sets of drop-hook hardware made of carbon steel (4), stainless steel (4), and aluminum (3). Replicated seat-loading conditions associated with a 20g/48 kph frontal impact. Test criterion for seat loading was 16,680 N (3750 lb). Failure load and deflection of seat surface. None of the hardware sets tested met the crashworthiness test criterion. All failed at less than 50% of the load that seating hardware could be exposed to in a 20g/48 kph frontal impact. The primary failure mode was excessive deformation, leading to an unstable seat support surface. Results suggest that commercially available seating drop hooks may be unable to withstand loading associated with a frontal crash and may not be the best option for use with transport wheelchairs.

Crash Simulation of a Boeing 737 Fuselage Section Vertical Drop Test

NASA Technical Reports Server (NTRS)

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

2004-01-01

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

Evaluation of seismic spatial interaction effects through an impact testing program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, B.D.; Driesen, G.E.

The consequences of non-seismically qualified objects falling and striking essential, seismically qualified objects is an analytically difficult problem to assess. Analytical solutions to impact problems are conservative and only available for simple situations. In a nuclear facility, the numerous ``sources`` and ``targets`` requiring evaluation often have complex geometric configurations, which makes calculations and computer modeling difficult. Few industry or regulatory rules are available for this specialized assessment. A drop test program was recently conducted to ``calibrate`` the judgment of seismic qualification engineers who perform interaction evaluations and to further develop seismic interaction criteria. Impact tests on varying combinations of sourcesmore » and targets were performed by dropping the sources from various heights onto targets that were connected to instruments. This paper summarizes the scope, test configurations, and some results of the drop test program. Force and acceleration time history data and general observations are presented on the ruggedness of various targets when subjected to impacts from different types of sources.« less

Evaluation of seismic spatial interaction effects through an impact testing program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, B.D.; Driesen, G.E.

The consequences of non-seismically qualified objects falling and striking essential, seismically qualified objects is an analytically difficult problem to assess. Analytical solutions to impact problems are conservative and only available for simple situations. In a nuclear facility, the numerous sources'' and targets'' requiring evaluation often have complex geometric configurations, which makes calculations and computer modeling difficult. Few industry or regulatory rules are available for this specialized assessment. A drop test program was recently conducted to calibrate'' the judgment of seismic qualification engineers who perform interaction evaluations and to further develop seismic interaction criteria. Impact tests on varying combinations of sourcesmore » and targets were performed by dropping the sources from various heights onto targets that were connected to instruments. This paper summarizes the scope, test configurations, and some results of the drop test program. Force and acceleration time history data and general observations are presented on the ruggedness of various targets when subjected to impacts from different types of sources.« less

Microgravity Level Measurement of the Beijing Drop Tower Using a Sensitive Accelerometer

PubMed Central

Liu, T. Y.; Wu, Q. P.; Sun, B. Q.; Han, F. T.

2016-01-01

Drop tower is the most common ground-based facility to provide microgravity environment and widely used in many science experiments. A differential space accelerometer has been proposed to test the spin-gravity interaction between rotating extended bodies onboard a drag-free satellite. In order to assist design and test of this inertial sensor in a series of ground- based pre-flight experiments, it is very important to know accurately the residual acceleration of drop towers. In this report, a sensitive instrument for this purpose was built with a high-performance servo quartz accelerometer, and the dedicated interface electronics design providing small full-scale range and high sensitivity, up to 136.8 V/g0. The residual acceleration at the Beijing drop tower was measured using two different drop capsules. The experimental result shows that the microgravity level of the free-falling double capsule is better than 2 × 10−4g0 (Earth’s gravity). The measured data in this report provides critical microgravity information for design of the following ground experiments. PMID:27530726

B-52 Testing F-111 Parachute

NASA Technical Reports Server (NTRS)

1988-01-01

A mock-up of an F-111 cockpit section drops out of the bomb bay of NASA's B-52 mothership on a test flight of a new parachute system for the F-111 'Aardvark' bomber. The F-111's ejection system separated the entire cockpit from the rest of the aircraft, and a large parachute was then deployed to lower the cockpit section to the ground. NASA B-52, Tail Number 008, is an air launch carrier aircraft, 'mothership,' as well as a research aircraft platform that has been used on a variety of research projects. The aircraft, a 'B' model built in 1952 and first flown on June 11, 1955, is the oldest B-52 in flying status and has been used on some of the most significant research projects in aerospace history. Some of the significant projects supported by B-52 008 include the X-15, the lifting bodies, HiMAT (highly maneuverable aircraft technology), Pegasus, validation of parachute systems developed for the space shuttle program (solid-rocket-booster recovery system and the orbiter drag chute system), and the X-38. The B-52 served as the launch vehicle on 106 X-15 flights and flew a total of 159 captive-carry and launch missions in support of that program from June 1959 to October 1968. Information gained from the highly successful X-15 program contributed to the Mercury, Gemini, and Apollo human spaceflight programs as well as space shuttle development. Between 1966 and 1975, the B-52 served as the launch aircraft for 127 of the 144 wingless lifting body flights. In the 1970s and 1980s, the B-52 was the launch aircraft for several aircraft at what is now the Dryden Flight Research Center, Edwards, California, to study spin-stall, high-angle-of attack, and maneuvering characteristics. These included the 3/8-scale F-15/spin research vehicle (SRV), the HiMAT (Highly Maneuverable Aircraft Technology) research vehicle, and the DAST (drones for aerodynamic and structural testing). The aircraft supported the development of parachute recovery systems used to recover the space shuttle solid rocket booster casings. It also supported eight orbiter (space shuttle) drag chute tests in 1990. In addition, the B-52 served as the air launch platform for the first six Pegasus space boosters. During its many years of service, the B-52 has undergone several modifications. The first major modification was made by North American Aviation (now part of Boeing) in support of the X-15 program. This involved creating a launch-panel-operator station for monitoring the status of the test vehicle being carried, cutting a large notch in the right inboard wing flap to accommodate the vertical tail of the X-15 aircraft, and installing a wing pylon that enables the B-52 to carry research vehicles and test articles to be air-launched/dropped. Located on the right wing, between the inboard engine pylon and the fuselage, this wing pylon was subjected to extensive testing prior to its use. For each test vehicle the B-52 carried, minor changes were made to the launch-panel operator's station. Built originally by the Boeing Company, the NASA B-52 is powered by eight Pratt & Whitney J57-19 turbojet engines, each of which produce 12,000 pounds of thrust. The aircraft's normal launch speed has been Mach 0.8 (about 530 miles per hour) and its normal drop altitude has been 40,000 to 45,000 feet. It is 156 feet long and has a wing span of 185 feet. The heaviest load it has carried was the No. 2 X-15 aircraft at 53,100 pounds. Project manager for the aircraft is Roy Bryant.

B-52 Testing F-111 Parachute

NASA Technical Reports Server (NTRS)

1988-01-01

The main parachute begins to deploy on the mock-up of an F-111 'Aardvark' bomber cockpit section after being dropped from NASA's B-52 mothership during 1988 flight tests on improved parachute systems for the Air Force bomber. The F-111's ejection system separated the entire cockpit from the rest of the aircraft, and a large parachute was then deployed to lower the cockpit section to the ground. NASA B-52, Tail Number 008, is an air launch carrier aircraft, 'mothership,' as well as a research aircraft platform that has been used on a variety of research projects. The aircraft, a 'B' model built in 1952 and first flown on June 11, 1955, is the oldest B-52 in flying status and has been used on some of the most significant research projects in aerospace history. Some of the significant projects supported by B-52 008 include the X-15, the lifting bodies, HiMAT (highly maneuverable aircraft technology), Pegasus, validation of parachute systems developed for the space shuttle program (solid-rocket-booster recovery system and the orbiter drag chute system), and the X-38. The B-52 served as the launch vehicle on 106 X-15 flights and flew a total of 159 captive-carry and launch missions in support of that program from June 1959 to October 1968. Information gained from the highly successful X-15 program contributed to the Mercury, Gemini, and Apollo human spaceflight programs as well as space shuttle development. Between 1966 and 1975, the B-52 served as the launch aircraft for 127 of the 144 wingless lifting body flights. In the 1970s and 1980s, the B-52 was the launch aircraft for several aircraft at what is now the Dryden Flight Research Center, Edwards, California, to study spin-stall, high-angle-of attack, and maneuvering characteristics. These included the 3/8-scale F-15/spin research vehicle (SRV), the HiMAT (Highly Maneuverable Aircraft Technology) research vehicle, and the DAST (drones for aerodynamic and structural testing). The aircraft supported the development of parachute recovery systems used to recover the space shuttle solid rocket booster casings. It also supported eight orbiter (space shuttle) drag chute tests in 1990. In addition, the B-52 served as the air launch platform for the first six Pegasus space boosters. During its many years of service, the B-52 has undergone several modifications. The first major modification was made by North American Aviation (now part of Boeing) in support of the X-15 program. This involved creating a launch-panel-operator station for monitoring the status of the test vehicle being carried, cutting a large notch in the right inboard wing flap to accommodate the vertical tail of the X-15 aircraft, and installing a wing pylon that enables the B-52 to carry research vehicles and test articles to be air-launched/dropped. Located on the right wing, between the inboard engine pylon and the fuselage, this wing pylon was subjected to extensive testing prior to its use. For each test vehicle the B-52 carried, minor changes were made to the launch-panel operator's station. Built originally by the Boeing Company, the NASA B-52 is powered by eight Pratt & Whitney J57-19 turbojet engines, each of which produce 12,000 pounds of thrust. The aircraft's normal launch speed has been Mach 0.8 (about 530 miles per hour) and its normal drop altitude has been 40,000 to 45,000 feet. It is 156 feet long and has a wing span of 185 feet. The heaviest load it has carried was the No. 2 X-15 aircraft at 53,100 pounds. Project manager for the aircraft is Roy Bryant.

Viscosity Measurement via Drop Coalescence: A Space Station Experiment

NASA Technical Reports Server (NTRS)

Antar, Basil; Ethridge, Edwin C.

2010-01-01

The concept of using low gravity experimental data together with CFD simulations for measuring the viscosity of highly viscous liquids was recently validated on onboard the International Space Station (ISS). A series of microgravity tests were conducted for this purpose on the ISS in July, 2004 and in May of 2005. In these experiments two liquid drops were brought manually together until they touched and were allowed to coalesce under the action of the capillary force alone. The coalescence process was recorded photographically from which the contact radius speed of the merging drops was measured. The liquid viscosity was determined by fitting the measured data with accurate numerical simulation of the coalescence process. Several liquids were tested and for each liquid several drop diameters were employed. Experimental and numerical results will be presented in which the viscosity of several highly viscous liquids were determined using this technique.

Exciting New Take on a Classic: Crash Testing Activity Puts the Egg in the Driver's Seat

ERIC Educational Resources Information Center

Board, Keith

2011-01-01

An excellent common activity in technology and engineering classes involves dropping an egg from a significant height in a protective device designed and built by students. This article describes how the author uses the classic "egg drop" as an inspiration to have students modify a small crash test vehicle that speeds down a track and crashes into…

Exciting New Take on a Classic: Crash Test Activity Puts the Egg in the Driver's Seat

ERIC Educational Resources Information Center

Board, Keith

2011-01-01

An excellent common activity in technology and engineering classes involves dropping an egg from a significant height in a protective device designed and built by students. This article describes how the author uses the classic "egg drop" as an inspiration to have students modify a small crash test vehicle that speeds down a track and crashes into…

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

NASA Technical Reports Server (NTRS)

Kranz, M

1954-01-01

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

Development of a test facility and preliminary testing of flow boiling heat transfer of R410A refrigerant with Al2O3 nanolubricants

NASA Astrophysics Data System (ADS)

Wong, Thiam

In vapor compression cycles, a small portion of the oil circulates with the refrigerant throughout the system components, while most of the oil stays in the compressors. In heat exchangers, the lubricant in excess penalizes the heat transfer and increases the pressure losses: both effects are highly undesired but yet unavoidable. Nanoparticles dispersed in the excess lubricant are expected to provide enhancements in heat transfer. While solubility and miscibility of refrigerants in polyolesters (POE) lubricant are well established knowledge, there is a lack of information regarding if and how nanoparticles dispersed in the lubricant affect these properties. This thesis presents experimental data of solubility of two types of Al2O3 nanolubricants with refrigerant R-410A. The nanoparticles were dispersed in POE lubricant by using different surfactants and dispersion methods. The nanolubricants appeared to have slightly lower solubility than that of R-410A but actually the solid nanoparticles did not really interfere with the POE oil solubility characteristics. A test facility and experimental methodology was developed for the investigation of heat transfer coefficient and pressure drop. The pressure drop of the refrigerant lubricant mixtures during flow boiling depended on the mass flux of the refrigerant. Greater augmentation was seen in the pressure drop results with decreasing mass flow rate. Pure refrigerant R410A showed the lowest pressure drop, addition of nanolubricants to the refrigerant showed a slightly higher pressure drop and POE-refrigerant mixture showed the highest pressure drop in the tests conducted. Enhancement or degradation in heat transfer coefficient during flow boiling depended on the nanoparticle concentration in the lubricant as well as the lubricant concentration in refrigerant. R410A showed the highest heat transfer coefficient for all conditions tested. For a concentration of 1% nanolubricant in refrigerant, the heat transfer coefficient showed more enhancement with increase in nanoparticle concentration compared to POE refrigerant mixtures. For a concentration of 3% nanolubricant in refrigerant mixtures there was little to no enhancement for tests conducted.

Thermocapillary migration and interactions of bubbles and drops

NASA Technical Reports Server (NTRS)

Subramanian, R. Shankar; Balasubramaniam, R.

1994-01-01

Results from ground-based theoretical and experimental research on the motion of bubbles and drops in a temperature gradient are described and a brief account is given of plans for a flight experiment scheduled in 1994.

Mitigating pavement edge drop off.

DOT National Transportation Integrated Search

2015-12-01

The objective of this research was to investigate and document practices currently being used by the : Nebraska Department of Roads (NDOR) districts and other State DOTs to mitigate pavement edge : drop off. The NDOR has developed (or borrowed) and i...

Dropout policies and trends for students with and without disabilities.

PubMed

Kemp, Suzanne E

2006-01-01

Students with and without disabilities are dropping out of school at an alarming rate. However, the precise extent of the problem remains elusive because individual schools, school districts, and state departments of education often use different definitional criteria and calculation methods. In addition, specific reasons why students drop out continues to be speculative and minimal research exists validating current dropout prevention programs for students with and without disabilities. This study examined methods secondary school principals used to calculate dropout rates, reasons they believed students dropped out of school, and what prevention programs were being used for students with and without disabilities. Results indicated that school districts used calculation methods that minimized dropout rates, students with and without disabilities dropped out for similar reasons, and few empirically validated prevention programs were being implemented. Implications for practice and directions for future research are discussed.

Comparison of hemagglutination inhibition test and ELISA in quantification of antibodies to egg drop syndrome virus.

PubMed

Raj, G Dhinakar; Ratnapraba, S; Matheswaran, K; Nachimuthu, K

2004-01-01

A single-serum dilution ELISA for egg drop syndrome (EDS) virus-specific antibodies was developed. In testing 425 chicken sera it was found to have a 93.6% sensitivity and 98.7% specificity relative to a hemagglutination inhibition (HI) test. The correlation coefficient for ELISA and HI titers was 0.793. The ELISA was efficacious in quantification of both vaccinal and infection antibodies and could routinely be used for screening large numbers of field sera.

Characterization of Vertical Impact Device Acceleration Pulses Using Parametric Assessment: Phase 3 Wiaman Seat

DTIC Science & Technology

2016-07-01

711 HPW/RHCPT) and their in-house technical support contractor , Infoscitex, conducted a series of tests to identify the performance capabilities of...Cell Seat Configuration Drop Ht . (in) Mean Peak Acceleration (G) Mean Velocity Change (ft/s) SH1 WS1 20 80.08 ± 3.71 13.54 ± 0.49 SH2...6. Test Matrix for VID Response with WS2 Test Cell Seat (Felt) Configuration Drop Ht . (in) Mean Peak Acceleration (G

Effect of soil moisture content on the splash phenomenon reproducibility.

PubMed

Ryżak, Magdalena; Bieganowski, Andrzej; Polakowski, Cezary

2015-01-01

One of the methods for testing splash (the first phase of water erosion) may be an analysis of photos taken using so-called high-speed cameras. The aim of this study was to determine the reproducibility of measurements using a single drop splash of simulated precipitation. The height from which the drops fell resulted in a splash of 1.5 m. Tests were carried out using two types of soil: Eutric Cambisol (loamy silt) and Orthic Luvisol (sandy loam); three initial pressure heads were applied equal to 16 kPa, 3.1 kPa, and 0.1 kPa. Images for one, five, and 10 drops were recorded at a rate of 2000 frames per second. It was found that (i) the dispersion of soil caused by the striking of the 1st drop was significantly different from the splash impact caused by subsequent drops; (ii) with every drop, the splash phenomenon proceeded more reproducibly, that is, the number of particles of soil and/or water that splashed were increasingly close to each other; (iii) the number of particles that were detached during the splash were strongly correlated with its surface area; and (iv) the higher the water film was on the surface the smaller the width of the crown was.

Effect of Soil Moisture Content on the Splash Phenomenon Reproducibility

PubMed Central

Ryżak, Magdalena; Bieganowski, Andrzej; Polakowski, Cezary

2015-01-01

One of the methods for testing splash (the first phase of water erosion) may be an analysis of photos taken using so-called high-speed cameras. The aim of this study was to determine the reproducibility of measurements using a single drop splash of simulated precipitation. The height from which the drops fell resulted in a splash of 1.5 m. Tests were carried out using two types of soil: Eutric Cambisol (loamy silt) and Orthic Luvisol (sandy loam); three initial pressure heads were applied equal to 16 kPa, 3.1 kPa, and 0.1 kPa. Images for one, five, and 10 drops were recorded at a rate of 2000 frames per second. It was found that (i) the dispersion of soil caused by the striking of the 1st drop was significantly different from the splash impact caused by subsequent drops; (ii) with every drop, the splash phenomenon proceeded more reproducibly, that is, the number of particles of soil and/or water that splashed were increasingly close to each other; (iii) the number of particles that were detached during the splash were strongly correlated with its surface area; and (iv) the higher the water film was on the surface the smaller the width of the crown was. PMID:25785859

In vitro comparison of antimicrobial activity of aqueous decoction of Coriandrum sativum, and Dentol Drop with chlorhexidine on Streptococcus mutans.

PubMed

Moradian, Hamid; Bazargani, Abdollah; Rafiee, Azade; Nazarialam, Ali

2013-09-01

Dental caries is still remained as a major health problem. This problem has created a new interest to search for new antimicrobial agents from various sources including medicinal plants. Since limited data is available so far regarding the antibacterial effect of Coriandrum sativum seed and Dentol Drop against Streptococcus mutans, this study aims to assess this activity. This experimental study was conducted in Shiraz University of Medical Sciences. In vitro comparison of antimicrobial activity of aqueous decoction of Coriandrum sativum seed and Dentol drop with chlorhexidine against Streptococcus mutans was evaluated using disk diffusion and broth microdilution assays. Positive and negative controls were considered. The data was statistically analyzed by applying Kruskal-Wallis and Tukey post-hoc test to compare the groups using SPSS software (version 17). Dentol drop showed a remarkable antibacterial activity, in comparison with chlorhexidine, against S. mutans in the disk diffusion (p value = 0.005), and broth microdilution assays (p value = 0.0001). Based on the results of this study, Coriandrum sativum seed did not posses any antibacterial property. Coriandrum sativum seed showed no anti-Streptococcus mutans activity. Dentol drop exhibited a remarkable antibacterial activity against S. mutans when tested in vitro. Dentol drop can be further studied as a preventive measure for dental caries.

Adaptive magnetorheological seat suspension for shock mitigation

NASA Astrophysics Data System (ADS)

Singh, Harinder Jit

This research focuses on theoretical and experimental analysis of an adaptive seat suspension employing magnetorheological energy absorber with the objective of minimizing injury potential to seated occupant of different weights subjected to broader crash intensities. The research was segmented into three tasks: (1) development of magnetorheological energy absorber, (2) biodynamic modeling of a seated occupant, and (3) control schemes for shock mitigation. A linear stroking semi-active magnetorheological energy absorber (MREA) was designed, fabricated and tested for intense impact conditions with piston velocities up to 8 m/s. MREA design was optimized on the basis of Bingham-plastic model (BPM model) in order to maximize the energy absorption capabilities at high impact velocities. Computational fluid dynamics and magnetic FE analysis were conducted to validate MREA performance. Subsequently, low-speed cyclic testing (0-2 Hz subjected to 0-5.5 A) and high-speed drop testing (0-4.5 m/s at 0 A) were conducted for quantitative comparison with the numerical simulations. Later, a nonlinear four degrees-of-freedom biodynamic model representing a seated 50th percentile male occupant was developed on the basis of experiments conducted on Hybrid II 50th percentile male anthropomorphic test device. The response of proposed biodynamic model was compared quantitatively against two different biodynamic models from the literature that are heavily implemented for obtaining biodynamic response under impact conditions. The proposed biodynamic model accurately predicts peak magnitude, overall shape and the duration of the biodynamic transient response, with minimal phase shift. The biodynamic model was further validated against 16 impact tests conducted on horizontal accelerator facility at NAVAIR for two different shock intensities. Compliance effects of human body were also investigated on the performance of adaptive seat suspension by comparing the proposed biodynamic model response with that of a rigid body response. Finally, three different control schemes were analyzed for maximizing shock attenuation using semi-active magnetorheological energy absorber. High-speed drop experiments were conducted by dropping two rigid payloads of 240 and 340 lb mass from heights of 35 and 60 inch to simulate different impact intensities. First control scheme called constant stroking load control offered inflexible stroking load irrespective of varying impact severity or occupant weight. The other two control schemes: terminal trajectory control and optimal control adapted stroking load as per the shock intensity. The control schemes were compared on the basis of their adaptability and ease of implementation. These tools can serve as the basis for future research and development of state-of-the-art crashworthy seat suspension designs that further enhance occupant protection compared to limited performance of existing passive crashworthy concepts.

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

NASA Technical Reports Server (NTRS)

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

2000-01-01

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

Extension of drop experiments with the MIKROBA balloon drop facility

NASA Astrophysics Data System (ADS)

Sommer, K.; Kretzschmar, K.; Dorn, C.

1992-12-01

The German balloon drop facility MIKROBA extends the worldwide available drop experiment opportunities to the presently highest usable experimentation time span of 55 s at microgravity conditions better than 0.001 g. The microgravity period is started with the typical quasi-deal step function from 1 to 0 g. MIKROBA allows flexible experiment design, short access time, and easy hands-on payload integration. The transport to the operational height is realized by soft energies and technologies compatible with the earth's environment. Balloon campaigns are not restricted to a certain test range, i.e., several suitable sites are available all over the world. MIKROBA combines negligible mechanical loads at the mission start, typical of all drop facilities, with extremely low drop deceleration loads (less than g), due to the implemented three-stage parachute and airbag recovery subsystem.

Camphor-Crataegus berry extract combination dose-dependently reduces tilt induced fall in blood pressure in orthostatic hypotension.

PubMed

Belz, G G; Butzer, R; Gaus, W; Loew, D

2002-10-01

In order to test the efficacy of a combination of natural D-camphor and an extract of fresh crataegus berries (Korodin Herz-Kreislauf-Tropfen) on orthostatic hypotension, two similar, controlled, randomized studies were carried out in a balanced crossover design in 24 patients each with orthostatic dysregulation. The camphor-crataegus berry combination (CCC) was orally administered as a single regimen in 3 different dosages of 5 drops, 20 drops and 80 drops; a placebo with 20 drops of a 60% alcoholic solution served as control. Orthostatic hypotension was assessed with the tilt table test before and after medication. Source data of both studies were pooled and meta-analytically evaluated for all 48 patients. CCC drops decreased the orthostatic fall in blood pressure versus placebo, as almost uniformly established at all times by mean arterial pressure and diastolic blood pressure. Mean arterial pressure demonstrated the very fast onset of action by a clearly dose-dependent statistically significant effect even after 1-minute orthostasis. Increase of mean arterial pressure as compared to the orthostasis test before medication was on average 4.5 mmHg. CCC affected diastolic blood pressure after 1 minute of orthostasis in all dosages as compared to placebo. A statistically significant effect of the highest dose of 80 drops on diastolic blood pressure could be demonstrated after 1-, 3-, and 5-minute orthostasis. The hemodynamic findings of a stabilizing effect on arterial pressure in orthostasis corroborate the long-term medical experience with CCC and justify the indication orthostatic hypotension.

Drop jumping. I. The influence of jumping technique on the biomechanics of jumping.

PubMed

Bobbert, M F; Huijing, P A; van Ingen Schenau, G J

1987-08-01

In the literature, drop jumping is advocated as an effective exercise for athletes who prepare themselves for explosive activities. When executing drop jumps, different jumping techniques can be used. In this study, the influence of jumping technique on the biomechanics of jumping is investigated. Ten subjects executed drop jumps from a height of 20 cm and counter-movement jumps. For the execution of the drop jumps, two different techniques were adopted. The first technique, referred to as bounce drop jump, required the subjects to reverse the downward velocity into an upward one as soon as possible after landing. The second technique, referred to as counter-movement drop jump, required them to do this more gradually by making a larger downward movement. During jumping, the subjects were filmed, ground reaction forces were registered, and electromyograms were recorded. The results of a biomechanical analysis show that moments and power output about knee and ankle joints reach larger values during the drop jumps than during counter-movement jumps. The largest values were attained during bounce drop jumps. Based on this finding, it was hypothesized that bounce drop jump is better suited than counter-movement drop jump for athletes who seek to improve the mechanical output of knee extensors and plantar flexors. Researchers are, therefore, advised to control jumping technique when investigating training effects of executing drop jumps.

Air injection test on a Kaplan turbine: prototype - model comparison

NASA Astrophysics Data System (ADS)

Angulo, M.; Rivetti, A.; Díaz, L.; Liscia, S.

2016-11-01

Air injection is a very well-known resource to reduce pressure pulsation magnitude in turbines, especially on Francis type. In the case of large Kaplan designs, even when not so usual, it could be a solution to mitigate vibrations arising when tip vortex cavitation phenomenon becomes erosive and induces structural vibrations. In order to study this alternative, aeration tests were performed on a Kaplan turbine at model and prototype scales. The research was focused on efficiency of different air flow rates injected in reducing vibrations, especially at the draft tube and the discharge ring and also in the efficiency drop magnitude. It was found that results on both scales presents the same trend in particular for vibration levels at the discharge ring. The efficiency drop was overestimated on model tests while on prototype were less than 0.2 % for all power output. On prototype, air has a beneficial effect in reducing pressure fluctuations up to 0.2 ‰ of air flow rate. On model high speed image computing helped to quantify the volume of tip vortex cavitation that is strongly correlated with the vibration level. The hydrophone measurements did not capture the cavitation intensity when air is injected, however on prototype, it was detected by a sonometer installed at the draft tube access gallery.

A study of two-phase flow in a reduced gravity environment

NASA Technical Reports Server (NTRS)

Hill, D.; Downing, Robert S.

1987-01-01

A test loop was designed and fabricated for observing and measuring pressure drops of two-phase flow in reduced gravity. The portable flow test loop was then tested aboard the NASA-JSC KC135 reduced gravity aircraft. The test loop employed the Sundstrand Two-Phase Thermal Management System (TPTMS) concept which was specially fitted with a clear two-phase return line and condenser cover for flow observation. A two-phase (liquid/vapor) mixture was produced by pumping nearly saturated liquid through an evaporator and adding heat via electric heaters. The quality of the two-phase flow was varied by changing the evaporator heat load. The test loop was operated on the ground before and after the KC135 flight tests to create a one-gravity data base. The ground testing included all the test points run during the reduced gravity testing. Two days of reduced gravity tests aboard the KC135 were performed. During the flight tests, reduced-gravity, one-gravity, and nearly two-gravity accelerations were experienced. Data was taken during the entire flight which provided flow regime and pressure drop data for the three operating conditions. The test results show that two-phase pressure drops and flow regimes can be accurately predicted in zero-gravity.

Reliability of 3-Dimensional Measures of Single-Leg Cross Drop Landing Across 3 Different Institutions: Implications for Multicenter Biomechanical and Epidemiological Research on ACL Injury Prevention.

PubMed

DiCesare, Christopher A; Bates, Nathaniel A; Barber Foss, Kim D; Thomas, Staci M; Wordeman, Samuel C; Sugimoto, Dai; Roewer, Benjamin D; Medina McKeon, Jennifer M; Di Stasi, Stephanie; Noehren, Brian W; Ford, Kevin R; Kiefer, Adam W; Hewett, Timothy E; Myer, Gregory D

2015-12-01

Anterior cruciate ligament (ACL) injuries are physically and financially devastating but affect a relatively small percentage of the population. Prospective identification of risk factors for ACL injury necessitates a large sample size; therefore, study of this injury would benefit from a multicenter approach. To determine the reliability of kinematic and kinetic measures of a single-leg cross drop task across 3 institutions. Controlled laboratory study. Twenty-five female high school volleyball players participated in this study. Three-dimensional motion data of each participant performing the single-leg cross drop were collected at 3 institutions over a period of 4 weeks. Coefficients of multiple correlation were calculated to assess the reliability of kinematic and kinetic measures during the landing phase of the movement. Between-centers reliability for kinematic waveforms in the frontal and sagittal planes was good, but moderate in the transverse plane. Between-centers reliability for kinetic waveforms was good in the sagittal, frontal, and transverse planes. Based on these findings, the single-leg cross drop task has moderate to good reliability of kinematic and kinetic measures across institutions after implementation of a standardized testing protocol. Multicenter collaborations can increase study numbers and generalize results, which is beneficial for studies of relatively rare phenomena, such as ACL injury. An important step is to determine the reliability of risk assessments across institutions before a multicenter collaboration can be initiated.

Rain drop size densities over land and over sea

NASA Astrophysics Data System (ADS)

Bumke, Karl

2010-05-01

A detailed knowledge of rain drop size densities is an essential presumption with respect to remote sensing of precipitation. Since maritime and continental aerosol is significantly different yielding to differences in cloud drop size densities, maritime and continental rain drop size densities may be different, too. In fact only a little is known about differences in rain drop size densities between land and sea due to a lack of suitable data over the sea. To fill in this gap measurements were performed during the recent 10 years at different locations in Germany and on board of research vessels over the Baltic Sea, the North Sea, Atlantic, Indian, and Pacific Ocean. Measurements were done by using an optical disdrometer (ODM 470, Großklaus et al., 1998), which is designed especially to perform precipitation measurements on moving ships and under high wind speeds. Temporal resolution of measurements is generally 1 minute, total number of time series is about 220000. To investigate differences in drop size densities over land and over sea measurements have been divided into four classes on the basis of prevailing continental or maritime influence: land measurements, coastal measurements, measurements in areas of semi-enclosed seas, and open sea measurements. In general differences in drop size densities are small between different areas. A Kolmogoroff Smirnoff test does not give any significant difference between drop size densities over land, coastal areas, semi-enclosed, and open seas at an error rate of 5%. Thus, it can be concluded that there are no systematic differences between maritime and continental drop size densities. The best fit of drop size densities is an exponential decay curve, N(D ) = 6510m -3mm -1mm0.14h- 0.14×R-0.14×exp(- 4.4mm0.25h-0.25×R- 0.25×D mm -1), it is estimated by using the method of least squares. N(D) is the drop size density normalized by the resolution of the optical disdrometer, D the diameter of rain drops in mm, and R the precipitation rate in mmh-1.The precipitation rate dependent factor in the exponential is similar to that given by Marshall and Palmer (1948). The intercept parameter, in the original Marshall Palmer formulation not depending on the rain rate, is also of the same order. A number of recent publications have shown that drop size densities of convective and stratiform rain show significant differences, too. Several procedures have been developed in the past to decide, whether precipitation is of stratiform or convective character. Here two of them are used, temporal variability in rain rates and additional information by weather radar data for the South Western Baltic Sea. Main result is that differences in drop size densities depend on the integration time of measurements. For integration times of 1 minute no significant differences can be detected at an error rate of 5%, while integration times of 10 minutes yield to significant differences between drop size densities of prevailing stratiform and convective rain. References: Großklaus, M., K.Uhlig, and L.Hasse, 1998: An Optical Disdrometer for Use in High Wind Speeds, Journal of Atmospheric and Oceanic Technology Vol. 15(4). 1051-1059 Marshall, J.S. and W.M.K.Palmer, 1948: The distribution of rain drops with size, J. Meteor., 5, 165-166

Sasquatch Footprint Tool

NASA Technical Reports Server (NTRS)

Bledsoe, Kristin

2013-01-01

The Crew Exploration Vehicle Parachute Assembly System (CPAS) is the parachute system for NASA s Orion spacecraft. The test program consists of numerous drop tests, wherein a test article rigged with parachutes is extracted or released from an aircraft. During such tests, range safety is paramount, as is the recoverability of the parachutes and test article. It is crucial to establish an aircraft release point that will ensure that the article and all items released from it will land in safe locations. A new footprint predictor tool, called Sasquatch, was created in MATLAB. This tool takes in a simulated trajectory for the test article, information about all released objects, and atmospheric wind data (simulated or actual) to calculate the trajectories of the released objects. Dispersions are applied to the landing locations of those objects, taking into account the variability of winds, aircraft release point, and object descent rate. Sasquatch establishes a payload release point (e.g., where the payload will be extracted from the carrier aircraft) that will ensure that the payload and all objects released from it will land in a specified cleared area. The landing locations (the final points in the trajectories) are plotted on a map of the test range. Sasquatch was originally designed for CPAS drop tests and includes extensive information about both the CPAS hardware and the primary test range used for CPAS testing. However, it can easily be adapted for more complex CPAS drop tests, other NASA projects, and commercial partners. CPAS has developed the Sasquatch footprint tool to ensure range safety during parachute drop tests. Sasquatch is well correlated to test data and continues to ensure the safety of test personnel as well as the safe recovery of all equipment. The tool will continue to be modified based on new test data, improving predictions and providing added capability to meet the requirements of more complex testing.

Power transmission cable development for the Space Station Freedom electrical power system

NASA Technical Reports Server (NTRS)

Schmitz, Gregory V.; Biess, John J.

1989-01-01

Power transmission cable is presently being evaluated under a NASA Lewis Research Center advanced development contract for application in the Space Station Freedom (SSF) electrical power system (EPS). Evaluation testing has been performed by TRW and NASA Lewis Research Center. The results of this development contract are presented. The primary cable design goals are to provide (1) a low characteristic inductance to minimize line voltage drop at 20 kHz, (2) electromagnetic compatibility control of the 20-kHz ac power current, (3) a physical configuration that minimizes ac resistance and (4) release of trapped air for corona-free operation.

Flowrate testing of the bag filter LANCS-BOP 6CPVC-1.5-2SPVC (LANCS Industries) at 1 psig

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, Murray E.; Currie, Karissa Lyn; Berg, Charlotte Katherine

2016-09-13

The air flowrate through a flexible HEPA grade filter (Part LANCS-BOP 6CPVC-1.5-2SPVC www.lancsindustries.com) was measured at 48 ALPM for a differential pressure drop of 1.0 psig (28 inWC, 7.0 kPa). These filters are rated by the manufacturer to have a flowrate of 3 ALPM at a differential pressure drop of 1 inWC (0.25 kPa). The Los Alamos National Laboratory Aerosol Engineering Facility used one of their test rigs (originally developed to measure the pressure drop in capsule HEPA filters) to measure the airflow through the LANCS bag filter.

Student-Designed Fluid Experiment for DIME Competition

NASA Technical Reports Server (NTRS)

2002-01-01

Test tubes to hold different types of fluids while in free-fall were among the student-designed items for the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

Microgravity

NASA Image and Video Library

2002-08-07

A NASA test conductor at the top of the 2.2-second Drop Tower monitors a student lecture at a lower level. This was part of the Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

A steady state pressure drop model for screen channel liquid acquisition devices

NASA Astrophysics Data System (ADS)

Hartwig, J. W.; Darr, S. R.; McQuillen, J. B.; Rame, E.; Chato, D. J.

2014-11-01

This paper presents the derivation of a simplified one dimensional (1D) steady state pressure drop model for flow through a porous liquid acquisition device (LAD) inside a cryogenic propellant tank. Experimental data is also presented from cryogenic LAD tests in liquid hydrogen (LH2) and liquid oxygen (LOX) to compare against the simplified model and to validate the model at cryogenic temperatures. The purpose of the experiments was to identify the various pressure drop contributions in the analytical model which govern LAD channel behavior during dynamic, steady state outflow. LH2 pipe flow of LAD screen samples measured the second order flow-through-screen (FTS) pressure drop, horizontal LOX LAD outflow tests determined the relative magnitude of the third order frictional and dynamic losses within the channel, while LH2 inverted vertical outflow tests determined the magnitude of the first order hydrostatic pressure loss and validity of the full 1D model. When compared to room temperature predictions, the FTS pressure drop is shown to be temperature dependent, with a significant increase in flow resistance at LH2 temperatures. Model predictions of frictional and dynamic losses down the channel compare qualitatively with LOX LADs data. Meanwhile, the 1D model predicted breakdown points track the trends in the LH2 inverted outflow experimental results, with discrepancies being due to a non-uniform injection velocity across the LAD screen not accounted for in the model.

Water tribology on graphene.

PubMed

N'guessan, Hartmann E; Leh, Aisha; Cox, Paris; Bahadur, Prashant; Tadmor, Rafael; Patra, Prabir; Vajtai, Robert; Ajayan, Pulickel M; Wasnik, Priyanka

2012-01-01

Classical experiments show that the force required to slide liquid drops on surfaces increases with the resting time of the drop, t(rest), and reaches a plateau typically after several minutes. Here we use the centrifugal adhesion balance to show that the lateral force required to slide a water drop on a graphene surface is practically invariant with t(rest). In addition, the drop's three-phase contact line adopts a peculiar micrometric serrated form. These observations agree well with current theories that relate the time effect to deformation and molecular re-orientation of the substrate surface. Such molecular re-orientation is non-existent on graphene, which is chemically homogenous. Hence, graphene appears to provide a unique tribological surface test bed for a variety of liquid drop-surface interactions.

Impact, thermal, and shock sensitivity of molten TNT and of asphalt-contaminated molten TNT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mainiero, R.J.; Miron, Y.; Kwak, S.S.W.

1996-12-01

The research reported here was part of an effort to evaluate the safety of a process to recover TNT from MK-9 depth bombs by the autoclave meltout process. In this process the depth bombs are heated to 121 C so that the TNT will melt and run into a vat. Unfortunately, asphalt lining the inside surface of the bomb also melts and flows out with the TNT. Testing was conducted on molten TNT and molten TNT contaminated with 2 pct asphalt at 90, 100, 110, 120, 125, and 130 C. In the liquid drop test apparatus with a 2-kg weight,more » the molten TNT yielded a 50 pct probability of initiation at a drop height of 6.5 cm at 110 C, decreasing to 4.5 cm at 130 C. Asphalt-contaminated TNT was somewhat less impact-sensitive than pure TNT at temperatures of 110 to 125 C, but became more sensitive at 130 C. There is a 50 pct probability of initiation at a drop height of 7.8 cm at 110 C, decreasing to 3.3 cm at 130 C. In the card gap test, the molten TNT detonated at high velocity for a gap of 0.25 inches at 90 to 125 C and detonated at high velocity for a gap of 0.5 inches at 130 C. For gaps of 0.5 to 3 inches at 90 to 125 C and 0.75 inches to 3 inches at 130 C, the TNT did not detonate at high velocity but produced a violent explosion that caused significant damage to the test fixture. The thermal analysis test results showed that when asphalt is present in TNT, it greatly accelerates the exothermic decomposition of TNT, starting at temperatures near 200 C. It appears that at relatively low shock stimulus levels, the molten TNT may be undergoing a low velocity detonation, wherein the shock wave traveling through the gap test pipe cavitates the molten TNT, greatly increasing its sensitivity. These results are crucial for assuring continued safety in recovering TNT from munitions through the autoclave meltout process.« less

Microgravity

NASA Image and Video Library

2001-04-26

The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. Sandi Thompson of the National Center for Microgravity Research GRC makes a final adjustment to the drop package. This image is from a digital still camera; higher resolution is not available.

Parachute Drag Model

NASA Technical Reports Server (NTRS)

Cuthbert, Peter

2010-01-01

DTV-SIM is a computer program that implements a mathematical model of the flight dynamics of a missile-shaped drop test vehicle (DTV) equipped with a multistage parachute system that includes two simultaneously deployed drogue parachutes and three main parachutes deployed subsequently and simultaneously by use of pilot parachutes. DTV-SIM was written to support air-drop tests of the DTV/parachute system, which serves a simplified prototype of a proposed crew capsule/parachute landing system.

Low Velocity Airdrop Tests of an X-38 Backup Parachute Design

NASA Technical Reports Server (NTRS)

Stein, Jenny M.; Machin, Ricardo A.; Wolf, Dean F.; Hillebrandt, F. David

2007-01-01

The NASA Johnson Space Center's X-38 program designed a new backup parachute system to recover the 25,000 lb X-38 prototype for the Crew Return Vehicle spacecraft. Due to weight and cost constraints, the main backup parachute design incorporated rapid and low cost fabrication techniques using off-the-shelf materials. Near the vent, the canopy was constructed of continuous ribbons, to provide more damage tolerance. The remainder of the canopy was a constructed with a continuous ringslot design. After cancellation of the X-38 program, the parachute design was resized, built, and drop tested for Natick Soldiers Center's Low Velocity Air Drop (LVAD) program to deliver cargo loads up to 22,000 lbs from altitudes as low as 500 feet above the ground. Drop tests results showed that the 500-foot LVAD parachute deployment conditions cause severe skirt inversion and inflation problems for large parachutes. The bag strip occurred at a high angle of attack, causing skirt inversion before the parachute could inflate. The addition of a short reefing line prevented the skirt inversion. Using a lower porosity in the vent area, than is normally used in large parachutes, improved inflation. The drop testing demonstrated that the parachute design could be refined to meet the requirements for the 500-foot LVAD mission.

Friability Testing as a New Stress-Stability Assay for Biopharmaceuticals.

PubMed

Torisu, Tetsuo; Maruno, Takahiro; Yoneda, Saki; Hamaji, Yoshinori; Honda, Shinya; Ohkubo, Tadayasu; Uchiyama, Susumu

2017-10-01

A cycle of dropping and shaking a vial containing antibody solution was reported to induce aggregation. In this study, antibody solutions in glass prefillable syringes with or without silicone oil lubrication were subjected to the combined stresses of dropping and shaking, using a friability testing apparatus. Larger numbers of subvisible particles were generated, regardless of silicone oil lubrication, upon combination stress exposure than that with shaking stress alone. Nucleation of antibody molecules upon perturbation by an impact of dropping and adsorption of antibody molecules to the syringe surface followed by film formation and antibody film desorption were considered key steps in the particle formation promoted by combination stress. A larger number of silicone oil droplets was released when silicone oil-lubricated glass syringes containing phosphate buffer saline were exposed to combination stress than that observed with shaking stress alone. Polysorbate 20, a non-ionic surfactant, effectively reduced the number of protein particles, but failed to prevent silicone oil release upon combination stress exposure. This study indicates that stress-stability assays using the friability testing apparatus are effective for assessing the stability of biopharmaceuticals under the combined stresses of dropping and shaking, which have not been tested in conventional stress-stability assays. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Free Radical Scavenging Activity of Drops and Spray Containing Propolis-An EPR Examination.

PubMed

Olczyk, Pawel; Komosinska-Vassev, Katarzyna; Ramos, Pawel; Mencner, Lukasz; Olczyk, Krystyna; Pilawa, Barbara

2017-01-13

The influence of heating at a temperature of 50 °C and UV-irradiation of propolis drops and spray on their free radical scavenging activity was determined. The kinetics of interactions of the propolis samples with DPPH free radicals was analyzed. Interactions of propolis drops and propolis spray with free radicals were examined by electron paramagnetic resonance spectroscopy. A spectrometer generating microwaves of 9.3 GHz frequency was used. The EPR spectra of the model DPPH free radicals were compared with the EPR spectra of DPPH in contact with the tested propolis samples. The antioxidative activity of propolis drops and propolis spray decreased after heating at the temperature of 50 °C. A UV-irradiated sample of propolis drops more weakly scavenged free radicals than an untreated sample. The antioxidative activity of propolis spray increased after UV-irradiation. The sample of propolis drops heated at the temperature of 50 °C quenched free radicals faster than the unheated sample. UV-irradiation weakly changed the kinetics of propolis drops or spray interactions with free radicals. EPR analysis indicated that propolis drops and spray should not be stored at a temperature of 50 °C. Propolis drops should not be exposed to UV-irradiation.

Nonlinear electrohydrodynamics of leaky dielectric drops in the Quincke regime: Numerical simulations

NASA Astrophysics Data System (ADS)

Das, Debasish; Saintillan, David

2015-11-01

The deformation of leaky dielectric drops in a dielectric fluid medium when subject to a uniform electric field is a classic electrohydrodynamic phenomenon best described by the well-known Melcher-Taylor leaky dielectric model. In this work, we develop a three-dimensional boundary element method for the full leaky dielectric model to systematically study the deformation and dynamics of liquid drops in strong electric fields. We compare our results with existing numerical studies, most of which have been constrained to axisymmetric drops or have neglected interfacial charge convection by the flow. The leading effect of convection is to enhance deformation of prolate drops and suppress deformation of oblate drops, as previously observed in the axisymmetric case. The inclusion of charge convection also enables us to investigate the dynamics in the Quincke regime, in which experiments exhibit a symmetry-breaking bifurcation leading to a tank-treading regime. Our simulations confirm the existence of this bifurcation for highly viscous drops, and also reveal the development of sharp interfacial charge gradients driven by convection near the drop's equator. American Chemical Society, Petroleum Research Fund.

9. BUILDING NO. 620B, FRICTION PENDULUM BUILDING. 29FOOT DROP TOWER ...

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

9. BUILDING NO. 620-B, FRICTION PENDULUM BUILDING. 29-FOOT DROP TOWER SITS BEHIND BLAST SHIELD IN FRONT OF BUILDING. - Picatinny Arsenal, 600 Area, Test Areas District, State Route 15 near I-80, Dover, Morris County, NJ

49 CFR 173.184 - Highway or rail fusee.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) boxes, wooden (4C1, 4C2), plywood (4D) or reconstituted wood (4F) boxes or in fiberboard boxes (4G... drop test requirements (§ 178.603 of this subchapter), including at least one drop with spike in a...

49 CFR 173.184 - Highway or rail fusee.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) boxes, wooden (4C1, 4C2), plywood (4D) or reconstituted wood (4F) boxes or in fiberboard boxes (4G... drop test requirements (§ 178.603 of this subchapter), including at least one drop with spike in a...

Dispersion in Spherical Water Drops.

ERIC Educational Resources Information Center

Eliason, John C., Jr.

1989-01-01

Discusses a laboratory exercise simulating the paths of light rays through spherical water drops by applying principles of ray optics and geometry. Describes four parts: determining the output angles, computer simulation, explorations, model testing, and solutions. Provides a computer program and some diagrams. (YP)

Flow tests of a single fuel element coolant channel for a compact fast reactor for space power

NASA Technical Reports Server (NTRS)

Springborn, R. H.

1971-01-01

Water flow tests were conducted on a single-fuel-element cooling channel for a nuclear concept to be used for space power. The tests established a method for measuring coolant flow rate which is applicable to water flow testing of a complete mockup of the reference reactor. The inlet plenum-to-outlet plenum pressure drop, which approximates the overall core pressure drop, was measured and correlated with flow rate. This information can be used for reactor coolant flow and heat transfer calculations. An analytical study of the flow characteristics was also conducted.

Galileo Parachute System modification program

NASA Technical Reports Server (NTRS)

Mcmenamin, H. J.; Pochettino, L. R.

1984-01-01

This paper discusses the development program conducted on the Galileo Parachute System following the slow opening performance of the main parachute during the first system drop test. The parachute system is part of the Galileo entry probe that will descend through the Jupiter atmosphere. The uncontrolled parachute opening experienced in this test was not acceptable for the probe system. Therefore, the main parachute design was modified and the system sequence was changed to prevent a recurrence. These alterations and their system effects were evaluated analytically, and in a ground test program. At the conclusion of this phase, the system drop test was successfully repeated.

Measurement of Two-Phase Flow Characteristics Under Microgravity Conditions

NASA Technical Reports Server (NTRS)

Keshock, E. G.; Lin, C. S.; Edwards, L. G.; Knapp, J.; Harrison, M. E.; Xhang, X.

1999-01-01

This paper describes the technical approach and initial results of a test program for studying two-phase annular flow under the simulated microgravity conditions of KC-135 aircraft flights. A helical coil flow channel orientation was utilized in order to circumvent the restrictions normally associated with drop tower or aircraft flight tests with respect to two-phase flow, namely spatial restrictions preventing channel lengths of sufficient size to accurately measure pressure drops. Additionally, the helical coil geometry is of interest in itself, considering that operating in a microgravity environment vastly simplifies the two-phase flows occurring in coiled flow channels under 1-g conditions for virtually any orientation. Pressure drop measurements were made across four stainless steel coil test sections, having a range of inside tube diameters (0.95 to 1.9 cm), coil diameters (25 - 50 cm), and length-to-diameter ratios (380 - 720). High-speed video photographic flow observations were made in the transparent straight sections immediately preceding and following the coil test sections. A transparent coil of tygon tubing of 1.9 cm inside diameter was also used to obtain flow visualization information within the coil itself. Initial test data has been obtained from one set of KC-135 flight tests, along with benchmark ground tests. Preliminary results appear to indicate that accurate pressure drop data is obtainable using a helical coil geometry that may be related to straight channel flow behavior. Also, video photographic results appear to indicate that the observed slug-annular flow regime transitions agree quite reasonably with the Dukler microgravity map.

Internal Flows in Free Drops (IFFD)

NASA Technical Reports Server (NTRS)

Trinh, E. H.; Sadhal, Satwindar S.; Thomas, D. A.; Crouch, R. K.

1998-01-01

Within the framework of an Earth-based research task investigating the internal flows within freely levitated drops, a low-gravity technology development experiment has been designed and carried out within the NASA Glovebox facility during the STS-83 and STS-94 Shuttle flights (MSL-1 mission). The goal was narrowly defined as the assessment of the capabilities of a resonant single-axis ultrasonic levitator to stably position free drops in the Shuttle environment with a precision required for the detailed measurement of internal flows. The results of this entirely crew-operated investigation indicate that the approach is fundamentally sound, but also that the ultimate stability of the positioning is highly dependent on the residual acceleration characteristic of the Spacecraft, and to a certain extent, on the initial drop deployment of the drop. The principal results are: the measured dependence of the residual drop rotation and equilibrium drop shape on the ultrasonic power level, the experimental evaluation of the typical drop translational stability in a realistic low-gravity environment, and the semi-quantitative evaluation of background internal flows within quasi-isothermal drops. Based on these results, we conclude that the successful design of a full-scale Microgravity experiment is possible, and would allow accurate the measurement of thermocapillary flows within transparent drops. The need has been demonstrated, however, for the capability for accurately deploying the drop, for a quiescent environment, and for precise mechanical adjustments of the levitator.

Altitude test of several afterburner configurations on a turbofan engine with a hydrogen heater to simulate an elevated turbine discharge temperature

NASA Technical Reports Server (NTRS)

Johnsen, R. L.; Cullom, R. R.

1977-01-01

A performance test of several experimental afterburner configurations was conducted with a mixed-flow turbofan engine in an altitude facility. The simulated flight conditions were for Mach 1.4 at two altitudes, 12,190 and 14,630 meters. Turbine discharge temperatures of 889 and 1056 K were used. A production afterburner was tested for comparison. The research afterburners included partial forced mixers with V-gutter flameholders, a carburetted V-gutter flameholder, and a triple ring V-gutter flameholder with four swirl-can fuel mixers. Fuel injection variations were included. Performance data shown include augmented thrust ratio, thrust specific fuel consumption, combustion efficiency, and total pressure drop across the afterburner.

Developing Soil Models for Dynamic Impact Simulations

NASA Technical Reports Server (NTRS)

Fasanella, Edwin L.; Lyle, Karen H.; Jackson, Karen E.

2009-01-01

This paper describes fundamental soils characterization work performed at NASA Langley Research Center in support of the Subsonic Rotary Wing (SRW) Aeronautics Program and the Orion Landing System (LS) Advanced Development Program (ADP). LS-DYNA(Registered TradeMark)1 soil impact model development and test-analysis correlation results are presented for: (1) a 38-ft/s vertical drop test of a composite fuselage section, outfitted with four blocks of deployable energy absorbers (DEA), onto sand, and (2) a series of impact tests of a 1/2-scale geometric boilerplate Orion capsule onto soil. In addition, the paper will discuss LS-DYNA contact analysis at the soil/structure interface, methods used to estimate frictional forces, and the sensitivity of the model to density, moisture, and compaction.

The design, development, and flight test results of the Boeing 737 aircraft antennas for the ICAO demonstration of the TRSB microwave landing system

NASA Technical Reports Server (NTRS)

Campbell, T. G.; White, W. E.; Gilreath, M. C.

1976-01-01

The Research Support Flight System, a modified Boeing 737, was used to evaluate the performance of several aircraft antennas and locations for the Time Reference Scanning Beam (TRSB) Microwave Landing System (MLS). These tests were conducted at the National Aviation Facilities Experimental Center (NAFEC), Atlantic City, New Jersey on December 18, 1975. The flight tests measured the signal strength and all pertinent MLS data during a straight-in approach, a racetrack approach, and ICAO approach profiles using the independent antenna-receiver combinations simultaneously on the aircraft. Signal drop-outs were experienced during the various approaches but only a small percentage could be attributed to antenna pattern effects.

Different cellular effects of four anti-inflammatory eye drops on human corneal epithelial cells: independent in active components.

PubMed

Qu, Mingli; Wang, Yao; Yang, Lingling; Zhou, Qingjun

2011-01-01

To evaluate and compare the cellular effects of four commercially available anti-inflammatory eye drops and their active components on human corneal epithelial cells (HCECs) in vitro. The cellular effects of four eye drops (Bromfenac Sodium Hydrate Eye Drops, Pranoprofen Eye Drops, Diclofenac Sodium Eye Drops, and Tobramycin & Dex Eye Drops) and their corresponding active components were evaluated in an HCEC line with five in vitro assays. Cell proliferation and migration were measured using 3-(4,5)-dimethylthiahiazo (-z-y1)-3 5-di-phenytetrazoliumromide (MTT) assay and transwell migration assay. Cell damage was determined with the lactate dehydrogenase (LDH) assay. Cell viability and median lethal time (LT₅₀) were measured by 7-amino-actinomycin D (7-AAD) staining and flow cytometry analysis. Cellular effects after exposure of HCECs to the four anti-inflammatory eye drops were concentration dependent. The differences of cellular toxicity on cell proliferation became significant at lower concentrations (<0.002%). Diclofenac Sodium Eye Drops showed significant increasing effects on cell damage and viability when compared with the other three solutions. Tobramycin & Dex Eye Drops inhibited the migration of HCECs significantly. Tobramycin & Dex Eye Drops showed the quickest effect on cell viability: the LT₅₀ was 3.28, 9.23, 10.38, and 23.80 min for Tobramycin & Dex Eye Drops, Diclofenac Sodium Eye Drops, Pranoprofen Eye Drops, and Bromfenac Sodium Hydrate Eye Drops, respectively. However, the comparisons of cellular toxicity revealed significant differences between the eye drops and their active components under the same concentration. The corneal epithelial toxicity differences among the active components of the four eye drops became significant as higher concentration (>0.020%). The four anti-inflammatory eye drops showed different cellular effects on HCECs, and the toxicity was not related with their active components, which provides new reference for the clinical application and drug research and development.

Mkit: A Cell Migration Assay Based on Microfluidic Device and Smartphone

PubMed Central

Yang, Ke; Wu, Jiandong; Peretz-Soroka, Hagit; Zhu, Ling; Li, Zhigang; Sang, Yaoshuo; Hipolito, Jolly; Zhang, Michael; Santos, Susy; Hillier, Craig; de Faria, Ricardo Lobato; Liu, Yong; Lin, Francis

2017-01-01

Mobile sensing based on the integration of microfluidic device and smartphone, so-called MS2 technology, has enabled many applications over recent years, and continues to stimulate growing interest in both research communities and industries. In particular, it has been envisioned that MS2 technology can be developed for various cell functional assays to enable basic research and clinical applications. Toward this direction, in this paper, we describe the development of a MS2-based cell functional assay for testing cell migration (the Mkit). The system is constructed as an integrated test kit, which includes microfluidic chips, a smartphone-based imaging platform, the phone apps for image capturing and data analysis, and a set of reagent and accessories for performing the cell migration assay. We demonstrated that the Mkit can effectively measure purified neutrophil and cancer cell chemotaxis. Furthermore, neutrophil chemotaxis can be tested from a drop of whole blood using the Mkit with red blood cell (RBC) lysis. The effects of chemoattractant dose and gradient profile on neutrophil chemotaxis were also tested using the Mkit. In addition to research applications, we demonstrated the effective use of the Mkit for on-site test at the hospital and for testing clinical samples from chronic obstructive pulmonary disease patient. Thus, this developed Mkit provides an easy and integrated experimental platform for cell migration related research and potential medical diagnostic applications. PMID:28772229

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knudsen, Peter N.; Ganni, Venkatarao

2015-12-01

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

Drop Weight Impact Behavior of Al-Si-Cu Alloy Foam-Filled Thin-Walled Steel Pipe Fabricated by Friction Stir Back Extrusion

NASA Astrophysics Data System (ADS)

Hangai, Yoshihiko; Nakano, Yukiko; Utsunomiya, Takao; Kuwazuru, Osamu; Yoshikawa, Nobuhiro

2017-02-01

In this study, Al-Si-Cu alloy ADC12 foam-filled thin-walled stainless steel pipes, which exhibit metal bonding between the ADC12 foam and steel pipe, were fabricated by friction stir back extrusion. Drop weight impact tests were conducted to investigate the deformation behavior and mechanical properties of the foam-filled pipes during dynamic compression tests, which were compared with the results of static compression tests. From x-ray computed tomography observation, it was confirmed that the fabricated foam-filled pipes had almost uniform porosity and pore size distributions. It was found that no scattering of the fragments of collapsed ADC12 foam occurred for the foam-filled pipes owing to the existence of the pipe surrounding the ADC12 foam. Preventing the scattering of the ADC12 foam decreases the drop in stress during dynamic compression tests and therefore improves the energy absorption properties of the foam.

B-52 Flight Mission Symbology on Side of Craft

NASA Technical Reports Server (NTRS)

1993-01-01

A view of some of the mission markings, painted on the side of NASA's B-52 mothership, that tell the story of its colorful history. Just as combat aircraft would paint a bomb on the side of an aircraft for each bombing mission completed, NASA crew members painted a silhouette on the side of the B-52's fuselage to commemorate each drop of an X-15, lifting body, remotely piloted research vehicle, X-38 crew return vehicle, or other experimental vehicle or parachute system. NASA B-52, Tail Number 008, is an air launch carrier aircraft, 'mothership,' as well as a research aircraft platform that has been used on a variety of research projects. The aircraft, a 'B' model built in 1952 and first flown on June 11, 1955, is the oldest B-52 in flying status and has been used on some of the most significant research projects in aerospace history. Some of the significant projects supported by B-52 008 include the X-15, the lifting bodies, HiMAT (highly maneuverable aircraft technology), Pegasus, validation of parachute systems developed for the space shuttle program (solid-rocket-booster recovery system and the orbiter drag chute system), and the X-38. The B-52 served as the launch vehicle on 106 X-15 flights and flew a total of 159 captive-carry and launch missions in support of that program from June 1959 to October 1968. Information gained from the highly successful X-15 program contributed to the Mercury, Gemini, and Apollo human spaceflight programs as well as space shuttle development. Between 1966 and 1975, the B-52 served as the launch aircraft for 127 of the 144 wingless lifting body flights. In the 1970s and 1980s, the B-52 was the launch aircraft for several aircraft at what is now the Dryden Flight Research Center, Edwards, California, to study spin-stall, high-angle-of attack, and maneuvering characteristics. These included the 3/8-scale F-15/spin research vehicle (SRV), the HiMAT (Highly Maneuverable Aircraft Technology) research vehicle, and the DAST (drones for aerodynamic and structural testing). The aircraft supported the development of parachute recovery systems used to recover the space shuttle solid rocket booster casings. It also supported eight orbiter (space shuttle) drag chute tests in 1990. In addition, the B-52 served as the air launch platform for the first six Pegasus space boosters. During its many years of service, the B-52 has undergone several modifications. The first major modification was made by North American Aviation (now part of Boeing) in support of the X-15 program. This involved creating a launch-panel-operator station for monitoring the status of the test vehicle being carried, cutting a large notch in the right inboard wing flap to accommodate the vertical tail of the X-15 aircraft, and installing a wing pylon that enables the B-52 to carry research vehicles and test articles to be air-launched/dropped. Located on the right wing, between the inboard engine pylon and the fuselage, this wing pylon was subjected to extensive testing prior to its use. For each test vehicle the B-52 carried, minor changes were made to the launch-panel operator's station. Built originally by the Boeing Company, the NASA B-52 is powered by eight Pratt & Whitney J57-19 turbojet engines, each of which produce 12,000 pounds of thrust. The aircraft's normal launch speed has been Mach 0.8 (about 530 miles per hour) and its normal drop altitude has been 40,000 to 45,000 feet. It is 156 feet long and has a wing span of 185 feet. The heaviest load it has carried was the No. 2 X-15 aircraft at 53,100 pounds. Project manager for the aircraft is Roy Bryant.

49 CFR 173.184 - Highway or rail fusee.

Code of Federal Regulations, 2010 CFR

2010-10-01

... (3A2), wooden (4C1, 4C2), plywood (4D) or reconstituted wood (4F) boxes or in fiberboard boxes (4G... drop test requirements (§ 178.603 of this subchapter), including at least one drop with spike in a...

49 CFR 173.184 - Highway or rail fusee.

Code of Federal Regulations, 2011 CFR

2011-10-01

... (3A2), wooden (4C1, 4C2), plywood (4D) or reconstituted wood (4F) boxes or in fiberboard boxes (4G... drop test requirements (§ 178.603 of this subchapter), including at least one drop with spike in a...

49 CFR 173.184 - Highway or rail fusee.

Code of Federal Regulations, 2012 CFR

2012-10-01

... (3A2), wooden (4C1, 4C2), plywood (4D) or reconstituted wood (4F) boxes or in fiberboard boxes (4G... drop test requirements (§ 178.603 of this subchapter), including at least one drop with spike in a...

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

NASA Technical Reports Server (NTRS)

Peck, W D; Beard, A P

1933-01-01

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

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

NASA Technical Reports Server (NTRS)

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

2004-01-01

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

The Japanese containerless experiments

NASA Technical Reports Server (NTRS)

Azuma, Hisao

1990-01-01

There are three sets of Japanese containerless experiments. The first is Drop dynamics research. It consists of acoustic levitation and large amplitude drop oscillation. The second is Optical materials processing in an acoustic levitation furnace. And the third is Electrostatic levitator development by two different Japanese companies.

Development of Active Learning Curriculum for CASPER's Microgravity Drop Tower

NASA Astrophysics Data System (ADS)

Carmona-Reyes, Jorge; Wang, Li; York, Judy; Matthews, Lorin; Laufer, Rene; Cook, Mike; Schmoke, Jimmy; Hyde, Truell

2016-10-01

As CASPER's new drop tower comes on line, plans for correlated educational research curricula are underway. CASPER's educational research team is working on developing curricula specific to the CASPER drop tower, modeled on a contest currently in use by (BEST) Robotics Inc. within central Texas independent school districts. The curricula integrates age specific use of computer programming software packages such as ``Scratch'' with industry standard communication protocols and augmented reality applications. Content is constructed around an earth and space science framework, covering subjects such as stars and galaxies, matter and energy, fusion and fission at a middle school level. CASPER faculty are partnering with the Region 12 Service Center; this combination provides a wide range of expertise that includes professional development, pedagogical methods, computational thinking in addition to microgravity and space science research expertise. The details of this work will be presented and samples of the manner in which it is impacting the CASPER research and educational outreach partnership will be discussed.

Usefulness of a semi-quantitative procalcitonin test and the A-DROP Japanese prognostic scale for predicting mortality among adults hospitalized with community-acquired pneumonia.

PubMed

Kasamatsu, Yu; Yamaguchi, Toshimasa; Kawaguchi, Takashi; Tanaka, Nagaaki; Oka, Hiroko; Nakamura, Tomoyuki; Yamagami, Keiko; Yoshioka, Katsunobu; Imanishi, Masahito

2012-02-01

The solid-phase immunoassay, semi-quantitative procalcitonin (PCT) test (B R A H M S PCT-Q) can be used to rapidly categorize PCT levels into four grades. However, the usefulness of this kit for determining the prognosis of adult patients with community-acquired pneumonia (CAP) is unclear. A prospective study was conducted in two Japanese hospitals to evaluate the usefulness of this PCT test in determining the prognosis of adult patients with CAP. The accuracy of the age, dehydration, respiratory failure, orientation disturbance, pressure (A-DROP) scale proposed by the Japanese Respiratory Society for prediction of mortality due to CAP was also investigated. Hospitalized CAP patients (n = 226) were enrolled in the study. Comprehensive examinations were performed to determine PCT and CRP concentrations, disease severity based on the A-DROP, pneumonia severity index (PSI) and confusion, urea, respiratory rate, blood pressure, age ≥65 (CURB-65) scales and the causative pathogens. The usefulness of the biomarkers and prognostic scales for predicting each outcome were then examined. Twenty of the 170 eligible patients died. PCT levels were strongly positively correlated with PSI (ρ = 0.56, P < 0.0001), A-DROP (ρ = 0.61, P < 0.0001) and CURB-65 scores (ρ = 0.58, P < 0.0001). The areas under the receiver operating characteristic curves (95% CI) for prediction of survival, for CRP, PCT, A-DROP, CURB-65, and PSI were 0.54 (0.42-0.67), 0.80 (0.70-0.90), 0.88 (0.82-0.94), 0.88 (0.82-0.94), and 0.89 (0.85-0.94), respectively. The 30-day mortality among patients who were PCT-positive (≥0.5 ng/mL) was significantly higher than that among PCT-negative patients (log-rank test, P < 0.001). The semi-quantitative PCT test and the A-DROP scale were found to be useful for predicting mortality in adult patients with CAP. © 2011 The Authors. Respirology © 2011 Asian Pacific Society of Respirology.

Soil Overconsolidation Changes Caused by Dynamic Replacement

NASA Astrophysics Data System (ADS)

Piotr, Kanty; Sławomir, Kwiecień; Jerzy, Sękowski

2017-10-01

In the dynamic replacement method (DR) the soil is improved by initially dropping a large weight (typically 8-20 t) pounder from a significant height up to 25 m. The created crater is filled with a stronger material (gravel, rubble, stone aggregate, debris), and the pounder is dropped once or multiple times again. The construction of dynamic replacement pillars influences the parameters of the adjacent soil. It results from the energy generated by dropping a pounder into the soil. In the current practice, these changes are not taken into the account during the design. This paper focuses on the changes of overconsolidation ratio (OCR) and in situ coefficient of lateral earth pressure (K) values estimated base on cone penetration test (CPTU) and Dilatometric test (DMT) performed at a test site. A single column was constructed and the ground around the column was examined using CPTU and DMT, performed at different distances from the column centre (2, 3, 4 and 6 m) and at different time intervals (during construction and 1, 8, 30 days later). The column was constructed in so-called transition soils (between cohesive and non-cohesive). While interpreting the results of the research, the authors addressed the matter of choosing the procedure of OCR and K indication for transition soils (in this case described as silts and/or sandy silts). Overconsolidation changes may differ depending on the chosen analysis procedure (for cohesive or non-cohesive soils). On the basis of the analysis presented in the paper and the observation of soil (acknowledged as cohesive according to macroscopic observations) during column excavation, it was decided that for more detailed analyses methods dedicated to cohesive soils should be applied. Generally, it can be stated that although the changes were complex, DR pillar formation process resulted in the increase of these parameters. The average increases of OCR and K values were 25% and 10% respectively. The post installation values are not significant from the engineering point of view, but they represent the influence of the formation process of only a single column. The described results indicate that Priebe’s column dimensioning method should be applied with caution, as it assumes the value K=1 which was not obtained in the described research. The results from the conducted tests indicate that different mechanisms occur during stone column formation with vibro-replacement and dynamic replacement. As the authors did not manage to find literature describing the results of K tests in the surrounding of a DR column, the presented results should be acknowledged as significant for designers who will apply the dynamic replacement method.

An Auto-Tuning PI Control System for an Open-Circuit Low-Speed Wind Tunnel Designed for Greenhouse Technology

PubMed Central

Espinoza, Karlos; Valera, Diego L.; Torres, José A.; López, Alejandro; Molina-Aiz, Francisco D.

2015-01-01

Wind tunnels are a key experimental tool for the analysis of airflow parameters in many fields of application. Despite their great potential impact on agricultural research, few contributions have dealt with the development of automatic control systems for wind tunnels in the field of greenhouse technology. The objective of this paper is to present an automatic control system that provides precision and speed of measurement, as well as efficient data processing in low-speed wind tunnel experiments for greenhouse engineering applications. The system is based on an algorithm that identifies the system model and calculates the optimum PI controller. The validation of the system was performed on a cellulose evaporative cooling pad and on insect-proof screens to assess its response to perturbations. The control system provided an accuracy of <0.06 m·s−1 for airflow speed and <0.50 Pa for pressure drop, thus permitting the reproducibility and standardization of the tests. The proposed control system also incorporates a fully-integrated software unit that manages the tests in terms of airflow speed and pressure drop set points. PMID:26274962

Design and testing of an energy-absorbing crewseat for the F/FB-111 aircraft, volume 1

NASA Technical Reports Server (NTRS)

Shane, S. J.

1985-01-01

A program to determine if the injury potential could be reduced by replacing the existing crewseats with energy absorbing crewseats is explored. An energy-absorbing test seat was designed using much of the existing seat hardware. An extensive dynamic seat test series, designed to duplicate various crew module ground impact conditions, was conducted at a sled test facility. Comparative tests with operational F-111 crewseats were also conducted. After successful dynamic testing of the seat, more testing was conducted with the seats mounted in an F-111 crew module. Both swing tests and vertical drop tests were conducted. The vertical drop tests were used to obtain comparative data between the energy-absorbing and operational seats. Volume 1 describes the energy absorbing test seat and testing conducted, and evaluates the data from both test series.

Transport Powder and Liquid Samples by Surface Acoustic Waves

NASA Technical Reports Server (NTRS)

Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Louyeh, Sahar

2009-01-01

Sample transport is an important requirement for In-situ analysis of samples in NASA planetary exploration missions. Tests have shown that powders or liquid drops on a surface can be transported by surface acoustic waves (SAW) that are generated on the surface using interdigital transducers. The phenomena were investigated experimentally and to generate SAWs interdigital electrodes were deposited on wafers of 128 deg rotated Y-cut LiNbO?. Transporting capability of the SAW device was tested using particles of various sizes and drops of various viscosities liquids. Because of different interaction mechanisms with the SAWs, the powders and the liquid drops were observed to move in opposite directions. In the preliminary tests, a speed of 180 mm/s was achieved for powder transportation. The detailed experimental setup and results are presented in this paper. The transporting mechanism can potentially be applied to miniaturize sample analysis system or " lab-on-chip" devices.

Detection of antibodies against hepatitis A in blood spots dried on filter paper. Is this a reliable method for epidemiological studies?

PubMed Central

Gil, A.; González, A.; Dal-Ré, R.; Dominguez, V.; Astasio, P.; Aguilar, L.

1997-01-01

Diluted dried blood drops on filter paper were compared with serum samples as a specimen source for qualitative anti-HAV antibody determination by ELISA. A total of 298 serum samples and dried blood drops were collected from a population of healthy adolescents (15.3 +/- 1.2 years old). The prevalence of anti-HAV antibody obtained by testing serum samples was 7.7% (95% CI:4.8 10.1). Compared with serum sampling the sensitivity and specificity of diluted dried blood drops were 91.3 and 99.3%. The positive and negative predictive values were 91.3 and 99.3%, respectively, and the likelihood ratios of positive and negative results were 91 and 0.09. It is proposed that this test represents a reliable procedure for anti-HAV antibody testing. PMID:9129596

Digital antimicrobial susceptibility testing using the MilliDrop technology.

PubMed

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

2016-03-01

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

X-38 Drop Model: Glides to Earth After Being Dropped from a Cessna

NASA Technical Reports Server (NTRS)

1995-01-01

A 4-foot-long model of NASA's X-38, an experimental crew return vehicle, glides to earth after being dropped from a Cessna aircraft in late 1995. The model was used to test the ram-air parafoil landing system, which could allow for accurate and controlled landings of an emergency Crew Return Vehicle spacecraft returning to Earth. The X-38 Crew Return Vehicle (CRV) research project is designed to develop the technology for a prototype emergency crew return vehicle, or lifeboat, for the International Space Station. The project is also intended to develop a crew return vehicle design that could be modified for other uses, such as a joint U.S. and international human spacecraft that could be launched on the French Ariane-5 Booster. The X-38 project is using available technology and off-the-shelf equipment to significantly decrease development costs. Original estimates to develop a capsule-type crew return vehicle were estimated at more than $2 billion. X-38 project officials have estimated that development costs for the X-38 concept will be approximately one quarter of the original estimate. Off-the-shelf technology is not necessarily 'old' technology. Many of the technologies being used in the X-38 project have never before been applied to a human-flight spacecraft. For example, the X-38 flight computer is commercial equipment currently used in aircraft and the flight software operating system is a commercial system already in use in many aerospace applications. The video equipment for the X-38 is existing equipment, some of which has already flown on the space shuttle for previous NASA experiments. The X-38's primary navigational equipment, the Inertial Navigation System/Global Positioning System, is a unit already in use on Navy fighters. The X-38 electromechanical actuators come from previous joint NASA, U.S. Air Force, and U.S. Navy research and development projects. Finally, an existing special coating developed by NASA will be used on the X-38 thermal tiles to make them more durable than those used on the space shuttles. The X-38 itself was an unpiloted lifting body designed at 80 percent of the size of a projected emergency crew return vehicle for the International Space Station, although two later versions were planned at 100 percent of the CRV size. The X-38 and the actual CRV are patterned after a lifting-body shape first employed in the Air Force-NASA X-24 lifting-body project in the early to mid-1970s. The current vehicle design is base lined with life support supplies for about nine hours of orbital free flight from the space station. It's landing will be fully automated with backup systems which allow the crew to control orientation in orbit, select a deorbit site, and steer the parafoil, if necessary. The X-38 vehicles (designated V131, V132, and V-131R) are 28.5 feet long, 14.5 feet wide, and weigh approximately 16,000 pounds on average. The vehicles have a nitrogen-gas-operated attitude control system and a bank of batteries for internal power. The actual CRV to be flown in space was expected to be 30 feet long. The X-38 project is a joint effort between the Johnson Space Center, Houston, Texas (JSC), Langley Research Center, Hampton, Virginia (LaRC) and Dryden Flight Research Center, Edwards, California (DFRC) with the program office located at JSC. A contract was awarded to Scaled Composites, Inc., Mojave, California, for construction of the X-38 test airframes. The first vehicle was delivered to the JSC in September 1996. The vehicle was fitted with avionics, computer systems and other hardware at Johnson. A second vehicle was delivered to JSC in December 1996. Flight research with the X-38 at Dryden began with an unpiloted captive-carry flight in which the vehicle remained attached to its future launch vehicle, Dryden's B-52 008. There were four captive flights in 1997 and three in 1998, plus the first drop test on March 12, 1998, using the parachutes and parafoil. Further captive and drop tests occurred in 1999. In March 2000 Vehicle 132 completed its third and final free flight in the highest, fastest, and longest X-38 flight to date. It was released at an altitude of 39,000 feet and flew freely for 45 seconds, reaching a speed of over 500 miles per hour before deploying its parachutes for a landing on Rogers Dry Lakebed. In the drop tests, the X-38 vehicles have been autonomous after airlaunch from the B-52. After they deploy the parafoil, they have remained autonomous, but there is also a manual mode with controls from the ground.

Pegasus air-launched space booster flight test program

NASA Astrophysics Data System (ADS)

Elias, Antonio L.; Knutson, Martin A.

1995-03-01

Pegasus is a satellite-launching space rocket dropped from a B52 carrier aircraft instead of launching vertically from a ground pad. Its three-year, privately-funded accelerated development was carried out under a demanding design-to-nonrecurring cost methodology, which imposed unique requirements on its flight test program, such as the decision not to drop an inert model from the carrier aircraft; the number and type of captive and free-flight tests; the extent of envelope exploration; and the decision to combine test and operational orbital flights. The authors believe that Pegasus may be the first vehicle where constraints in the number and type of flight tests to be carried out actually influenced the design of the vehicle. During the period November 1989 to February of 1990 a total of three captive flight tests were conducted, starting with a flutter clearing flight and culminating in a complete drop rehearsal. Starting on April 5, 1990, two combination test/operational flights were conducted. A unique aspect of the program was the degree of involvement of flight test personnel in the early design of the vehicle and, conversely, of the design team in flight testing and early flight operations. Various lessons learned as a result of this process are discussed throughout this paper.

In vitro comparison of antimicrobial activity of aqueous decoction of Coriandrum sativum, and Dentol Drop with chlorhexidine on Streptococcus mutans

PubMed Central

Moradian, Hamid; Bazargani, Abdollah; Rafiee, Azade; Nazarialam, Ali

2013-01-01

Background and objectives Dental caries is still remained as a major health problem. This problem has created a new interest to search for new antimicrobial agents from various sources including medicinal plants. Since limited data is available so far regarding the antibacterial effect of Coriandrum sativum seed and Dentol Drop against Streptococcus mutans, this study aims to assess this activity. Materials and Methods This experimental study was conducted in Shiraz University of Medical Sciences. In vitro comparison of antimicrobial activity of aqueous decoction of Coriandrum sativum seed and Dentol drop with chlorhexidine against Streptococcus mutans was evaluated using disk diffusion and broth microdilution assays. Positive and negative controls were considered. The data was statistically analyzed by applying Kruskal-Wallis and Tukey post-hoc test to compare the groups using SPSS software (version 17). Results Dentol drop showed a remarkable antibacterial activity, in comparison with chlorhexidine, against S. mutans in the disk diffusion (p value = 0.005), and broth microdilution assays (p value = 0.0001). Based on the results of this study, Coriandrum sativum seed did not posses any antibacterial property. Conclusion Coriandrum sativum seed showed no anti-Streptococcus mutans activity. Dentol drop exhibited a remarkable antibacterial activity against S. mutans when tested in vitro. Dentol drop can be further studied as a preventive measure for dental caries. PMID:24475330

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

NASA Technical Reports Server (NTRS)

Jackson, Karen E.; Fasanella, Edwin L.

2004-01-01

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

Investigation of Concrete Floor Vibration Using Heel-Drop Test

NASA Astrophysics Data System (ADS)

Azaman, N. A. Mohd; Ghafar, N. H. Abd; Azhar, A. F.; Fauzi, A. A.; Ismail, H. A.; Syed Idrus, S. S.; Mokhjar, S. S.; Hamid, F. F. Abd

2018-04-01

In recent years, there is an increased in floor vibration problems of structures like residential and commercial building. Vibration is defined as a serviceability issue related to the comfort of the occupant or damage equipment. Human activities are the main source of vibration in the building and it could affect the human comfort and annoyance of residents in the building when the vibration exceed the recommend level. A new building, Madrasah Tahfiz located at Yong Peng have vibration problem when load subjected on the first floor of the building. However, the limitation of vibration occurs on building is unknown. Therefore, testing is needed to determine the vibration behaviour (frequency, damping ratio and mode shape) of the building. Heel-drop with pace 2Hz was used in field measurement to obtain the vibration response. Since, the heel-drop test results would vary in light of person performance, test are carried out three time to reduce uncertainty. Natural frequency from Frequency Response Function analysis (FRF) is 17.4Hz, 16.8, 17.4Hz respectively for each test.

Glaucoma Medication Adherence among African Americans: Program Development

PubMed Central

Dreer, Laura E.; Girkin, Christopher A.; Campbell, Lisa; Wood, Andy; Gao, Liyan; Owsley, Cynthia

2014-01-01

Purpose To elucidate barriers and facilitators related to glaucoma medication adherence among African Americans (AA) with glaucoma and to elicit input from a community-based participatory research team in order to guide the development of a culturally informed, health promotion program for improving glaucoma medication adherence among AA’s. Methods The nominal group technique (NGT), a highly structured focus group methodology, was implemented with 12 separate groups of AA’s patients with glaucoma (N = 89) to identify barriers and facilitators related to glaucoma medication usage. Participant rank-ordering votes were summed across groups and categorized into themes. Next, an individually and culturally targeted health promotion program promoting appropriate medication adherence was developed based on focus group results and input from a community-based participatory research team. Results The top five barriers included problems with 1) forgetfulness, 2) side effects, 3) cost/affordability, 4) eye drop administration, and 5) the eye drop schedule. The most salient top five facilitators were 1) fear or thoughts about the consequences of not taking eye drops, 2) use of memory aids, cues, or strategies, 3) maintaining a regular routine or schedule for eye drop administration, 4) ability to afford eye drops, and 5) keeping eye drops in the same area. The resulting health promotion program was based on a multi-component empowerment framework that included glaucoma education, motivational interviewing, and problem-solving training to improve glaucoma medication adherence. Conclusions Barriers and facilitators related to glaucoma medication adherence among AA’s are multifactorial. Based on the NGT themes and input from the community-based participatory research team, a culturally informed, health promotion program was designed and holds great promise for improving medication adherence among this vulnerable population. PMID:23873033

Respiratory allergy to inhaled bat guano.

PubMed

el-Ansary, E H; Tee, R D; Gordon, D J; Taylor, A J

1987-02-07

In the Sudan many asthmatic patients attribute their symptoms to inhalation of bat droppings. Design of the roofs of many Sudanese buildings allows black bats to roost; guano drops through cracks in the ceiling into the rooms below where it can be inhaled and cause allergic respiratory disorders. Seven atopic patients seen at Sennar Hospital with bat-related case-histories were investigated. Six had bronchial asthma and allergic rhinitis and one had asthma alone. Extracts of yellow hairy bat, black bat, and bat droppings were made. All seven patients had a positive skin prick test and specific IgE antibodies (RAST) to bat droppings. Three patients also had a positive RAST to both yellow and black bats and one patient to yellow bat. Droppings are probably the major allergen source in bat-related respiratory allergy.

Microgravity

NASA Image and Video Library

2001-04-26

The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. NASA and contractor personnel who conducted the DIME activity with the students. Shown (L-R) are: Eric Baumann (NASA, 2.2-second Drop Tower Facility manager), Daniel Dietrich (NASA) mentor for Sycamore High School team), Carol Hodanbosi (National Center for Microgravity Research; DIME staff), Richard DeLombard (NASA; DIME staff), Jose Carrion (GRC Akima, drop tower technician), Dennis Stocker (NASA; DIME staff), Peter Sunderland (NCMR, mentor for COSI Academy student team), Sandi Thompson (NSMR sabbatical teacher; DIME staff), Dan Woodard (MASA Microgravity Outreach Program Manager), Adam Malcolm (NASA co-op student; DIME staff), Carla Rosenberg (NCMR; DIME staff), and Twila Schneider (Infinity Technology; NASA Microgravity Research program contractor). This image is from a digital still camera; higher resolution is not available.

Blood drop patterns: Formation and applications.

PubMed

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

2016-05-01

The drying of a drop of blood or plasma on a solid substrate leads to the formation of interesting and complex patterns. Inter- and intra-cellular and macromolecular interactions in the drying plasma or blood drop are responsible for the final morphologies of the dried patterns. Changes in these cellular and macromolecular components in blood caused by diseases have been suspected to cause changes in the dried drop patterns of plasma and whole blood, which could be used as simple diagnostic tools to identify the health of humans and livestock. However, complex physicochemical driving forces involved in the pattern formation are not fully understood. This review focuses on the scientific development in microscopic observations and pattern interpretation of dried plasma and whole blood samples, as well as the diagnostic applications of pattern analysis. Dried drop patterns of plasma consist of intricate visible cracks in the outer region and fine structures in the central region, which are mainly influenced by the presence and concentration of inorganic salts and proteins during drying. The shrinkage of macromolecular gel and its adhesion to the substrate surface have been thought to be responsible for the formation of the cracks. Dried drop patterns of whole blood have three characteristic zones; their formation as functions of drying time has been reported in the literature. Some research works have applied engineering treatment to the evaporation process of whole blood samples. The sensitivities of the resultant patterns to the relative humidity of the environment, the wettability of the substrates, and the size of the drop have been reported. These research works shed light on the mechanisms of spreading, evaporation, gelation, and crack formation of the blood drops on solid substrates, as well as on the potential applications of dried drop patterns of plasma and whole blood in diagnosis. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Thermocapillary-Induced Phase Separation with Coalescence

NASA Technical Reports Server (NTRS)

Davis, Robert H.

2003-01-01

Research has been undertaken on interactions of two or more deformable drops (or bubbles) in a viscous fluid and subject to a temperature, gravitational, or flow field. An asymptotic theory for nearly spherical drops shows that small deformations reduce the coalescence and phase separation rates. Boundary-integral simulations for large deformations show that bubbles experience alignment and enhanced coalescence, whereas more viscous drops may break as a result of hydrodynamic interactions. Experiments for buoyancy motion confirm these observations. Simulations of the sedimentation of many drops show clustering phenomena due to deformations, which lead to enhanced phase separation rates, and simulations of sheared emulsions show that deformations cause a reduction in the effective viscosity.

Phase segregation due to simultaneous migration and coalescence

NASA Technical Reports Server (NTRS)

Davis, Robert H.

1994-01-01

The primary objective of the research is to perform ground-based analysis and experiments on the interaction and coalescence of drops (or bubbles) leading to macroscopic phase separation. Migration of the drops occurs as a result of the individual and collective action of gravity and thermocapillary effects. Larger drops migrate faster than smaller ones, leading to the possibility of collisions and coalescence. Coalescence increases the rate of macroscopic phase separation, since the result is larger drops with higher migration rates. It is hoped that the understanding gained will lead to the design of microgravity experiments to further elucidate the mechanisms governing coalescence and phase separation.

Investigating the formation of acid mine drainage of Toledo pyrite concentrate using column cells

NASA Astrophysics Data System (ADS)

Aguila, Diosa Marie

2018-01-01

Acid mine drainage (AMD) is an inevitable problem in mining and has adverse effects in water quality. Studying AMD formation will be valuable in controlling the composition of mine waters and in planning the rehabilitation method for a mine. In this research, kinetics of AMD formation of Toledo pyrite was studied using two column experiments. The mechanisms of AMD formation and the effects of various factors on pH drop were first studied. Another column test was done for validation and to study the role of Fe2+/Fe3+ ratio in the change of leachate pH. The first experiment revealed that time and particle size are the most significant factors. It was also observed that the sudden pH drop during the starting hours was due to cracks formed from beneficiation, and the formation of Fe(OH)3. The laddered behavior of pH thereafter was due to decrease in formation of Fe(OH)3, and the precipitates in pyrite surface that lowered the surface area available for pyrite oxidation. The results of the second experiment validated the laddered behavior of pH. It was also observed that particle size distribution and pyrite surface were affected by the change in pH. Fe2+/Fe3+ ratio of leachate generally decreased as pH dropped.

Research Pilot Milt Thompson in M2-F2 Aircraft Attached to B-52 Mothership

NASA Technical Reports Server (NTRS)

1966-01-01

NASA research pilot Milt Thompson sits in the M2-F2 'heavyweight' lifting body research vehicle before a 1966 test flight. The M2-F2 and the other lifting-body designs were all attached to a wing pylon on NASA's B-52 mothership and carried aloft. The vehicles were then drop-launched and, at the end of their flights, glided back to wheeled landings on the dry lake or runway at Edwards AFB. The lifting body designs influenced the design of the Space Shuttle and were also reincarnated in the design of the X-38 in the 1990s. NASA B-52, Tail Number 008, is an air launch carrier aircraft, 'mothership,' as well as a research aircraft platform that has been used on a variety of research projects. The aircraft, a 'B' model built in 1952 and first flown on June 11, 1955, is the oldest B-52 in flying status and has been used on some of the most significant research projects in aerospace history. Some of the significant projects supported by B-52 008 include the X-15, the lifting bodies, HiMAT (highly maneuverable aircraft technology), Pegasus, validation of parachute systems developed for the space shuttle program (solid-rocket-booster recovery system and the orbiter drag chute system), and the X-38. The B-52 served as the launch vehicle on 106 X-15 flights and flew a total of 159 captive-carry and launch missions in support of that program from June 1959 to October 1968. Information gained from the highly successful X-15 program contributed to the Mercury, Gemini, and Apollo human spaceflight programs as well as space shuttle development. Between 1966 and 1975, the B-52 served as the launch aircraft for 127 of the 144 wingless lifting body flights. In the 1970s and 1980s, the B-52 was the launch aircraft for several aircraft at what is now the Dryden Flight Research Center, Edwards, California, to study spin-stall, high-angle-of attack, and maneuvering characteristics. These included the 3/8-scale F-15/spin research vehicle (SRV), the HiMAT (Highly Maneuverable Aircraft Technology) research vehicle, and the DAST (drones for aerodynamic and structural testing). The aircraft supported the development of parachute recovery systems used to recover the space shuttle solid rocket booster casings. It also supported eight orbiter (space shuttle) drag chute tests in 1990. In addition, the B-52 served as the air launch platform for the first six Pegasus space boosters. During its many years of service, the B-52 has undergone several modifications. The first major modification was made by North American Aviation (now part of Boeing) in support of the X-15 program. This involved creating a launch-panel-operator station for monitoring the status of the test vehicle being carried, cutting a large notch in the right inboard wing flap to accommodate the vertical tail of the X-15 aircraft, and installing a wing pylon that enables the B-52 to carry research vehicles and test articles to be air-launched/dropped. Located on the right wing, between the inboard engine pylon and the fuselage, this wing pylon was subjected to extensive testing prior to its use. For each test vehicle the B-52 carried, minor changes were made to the launch-panel operator's station. Built originally by the Boeing Company, the NASA B-52 is powered by eight Pratt & Whitney J57-19 turbojet engines, each of which produce 12,000 pounds of thrust. The aircraft's normal launch speed has been Mach 0.8 (about 530 miles per hour) and its normal drop altitude has been 40,000 to 45,000 feet. It is 156 feet long and has a wing span of 185 feet. The heaviest load it has carried was the No. 2 X-15 aircraft at 53,100 pounds. Project manager for the aircraft is Roy Bryant.

Ocular Surface Disease in Glaucoma: Effect of Polypharmacy and Preservatives.

PubMed

Ramli, Norlina; Supramaniam, Gowri; Samsudin, Amir; Juana, Azida; Zahari, Mimiwati; Choo, May May

2015-09-01

To evaluate the prevalence of ocular surface disease (OSD) in glaucoma and nonglaucoma subjects using different clinical tests and to determine the effect of number of antiglaucoma medications and preservatives on OSD. This is a cross-sectional, case-comparison study at the Eye Clinic of the University of Malaya Medical Centre, Malaysia, between June 2012 and January 2013. Glaucoma subjects (n = 105) using topical antiglaucoma medications were compared with control subjects (n = 102) who were not on any topical medications. The presence of OSD was assessed using the tear film breakup time (TBUT) test, corneal staining, Schirmer test, and Ocular Surface Disease Index (OSDI) questionnaire grading. The prevalence of OSD varied from 37 to 91% in the glaucoma group, depending on the type of clinical test. More subjects in the glaucoma group had corneal staining (63% vs. 36%, p = 0.004), abnormal Schirmer tests (39% vs. 25%, p = 0.049), and moderate OSDI symptoms (17% vs. 7%, p = 0.028). The percentage with abnormal TBUT increased with higher numbers of topical medications and was high with both benzalkonium chloride-containing and preservative-free eye drops (90% and 94%, respectively, both p < 0.001). Benzalkonium chloride was associated with a nearly three times higher odds ratio of showing abnormal OSDI. Ocular surface disease is common in those using topical antiglaucoma medications. Abnormal TBUT is associated with increasing number of eye drops and benzalkonium chloride-containing eye drops, although this also occurs with the use of preservative-free eye drops.

Measurement and modelling of forced convective heat transfer coefficient and pressure drop of Al2O3- and SiO2-water nanofluids

NASA Astrophysics Data System (ADS)

Julia, J. E.; Hernández, L.; Martínez-Cuenca, R.; Hibiki, T.; Mondragón, R.; Segarra, C.; Jarque, J. C.

2012-11-01

Forced convective heat transfer coefficient and pressure drop of SiO2- and Al2O3-water nanofluids were characterized. The experimental facility was composed of thermal-hydraulic loop with a tank with an immersed heater, a centrifugal pump, a bypass with a globe valve, an electromagnetic flow-meter, a 18 kW in-line pre-heater, a test section with band heaters, a differential pressure transducer and a heat exchanger. The test section consists of a 1000 mm long aluminium pipe with an inner diameter of 31.2 mm. Eighteen band heaters were placed all along the test section in order to provide a uniform heat flux. Heat transfer coefficient was calculated measuring fluid temperature using immersed thermocouples (Pt100) placed at both ends of the test section and surface thermocouples in 10 axial locations along the test section (Pt1000). The measurements have been performed for different nanoparticles (Al2O3 and SiO2 with primary size of 11 nm and 12 nm, respectively), volume concentrations (1% v., 5% v.), and flow rates (3 103Re<105). Maximum heat transfer coefficient enhancement (300%) and pressure drop penalty (1000%) is obtained with 5% v. SiO2 nanofluid. Existing correlations can predict, at least in a first approximation, the heat transfer coefficient and pressure drop of nanofluids if thermal conductivity, viscosity and specific heat were properly modelled.

Anomalous interfacial tension temperature dependence of condensed phase drops in magnetic fluids

NASA Astrophysics Data System (ADS)

Ivanov, Aleksey S.

2018-05-01

Interfacial tension temperature dependence σ(T) of the condensed phase (drop-like aggregates) in magnetic fluids undergoing field induced phase transition of the "gas-liquid" type was studied experimentally. Numerical analysis of the experimental data has revealed the anomalous (if compared to ordinary one-component fluids) behavior of the σ(T) function for all tested magnetic colloid samples: the condensed phase drops at high T ≈ 75 C exhibit higher σ(T) than the drops condensed at low T ≈ 20 C. The σ(T) behavior is explained by the polydispersity of magnetic colloids: at high T, only the largest colloidal particles are able to take part in the field induced condensation; thus, the increase of T causes the growth of the average particle diameters inside the drop-like aggregates, what in its turn results in the growth of σ(T). The result is confirmed by qualitative theoretical estimations and qualitative experimental observation of the condensed phase "evaporation" process after the applied magnetic field is removed: the drops that are formed due to capillary instability of the drop-like aggregates retract by one order of magnitude faster at high T, and the evaporation of the drops slows down at high T.

Evaporation of oil-water emulsion drops when heated at high temperature

NASA Astrophysics Data System (ADS)

Strizhak, P. A.; Piskunov, M. V.; Kuznetsov, G. V.; Voytkov, I. S.

2017-10-01

An experimental study on conditions and main characteristics for high-temperature (more than 700 K) evaporation of oil-water drops is presented. The high-temperature water purification from impurities can be the main practical application of research results. Thus, the heating of drops is implemented by the two typical schemes: on a massive substrate (the heating conditions are similar to those achieved in a heating chamber) and in a flow of the heated air. In the latter case, the heating conditions correspond to those attained while moving water drops with impurities in a counter high-temperature gaseous flow in the process of water purification. Evaporation time as function of heating temperature is presented. The influence of oil product concentration in an emulsion drop on evaporation characteristics is discussed. The conditions for intensive flash boiling of an emulsion drop and its explosive breakup with formation of the fine droplets cloud are pointed out. Heat fluxes required for intensive flash boiling and explosive breakup of a drop with further formation of the fine aerosol are determined in the boundary layer of a drop. The fundamental differences between flash boiling and explosive breakup of an emulsion drop when heated on a substrate and in a flow of the heated air are described. The main prospects for the development of the high-temperature water purification technology are detailed taking into account the fast emulsion drop breakup investigated in the paper.

Drops moving along and across a filament

NASA Astrophysics Data System (ADS)

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

2013-11-01

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

Single Channel Testing for Characterization of the Direct Gas Cooled Reactor and the SAFE-100 Heat Exchanger

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bragg-Sitton, S.M.; Propulsion Research Center, NASA Marshall Space Flight Center, Huntsville, AL 35812; Kapernick, R.

2004-02-04

Experiments have been designed to characterize the coolant gas flow in two space reactor concepts that are currently under investigation by NASA Marshall Space Flight Center and Los Alamos National Laboratory: the direct-drive gas-cooled reactor (DDG) and the SAFE-100 heatpipe-cooled reactor (HPR). For the DDG concept, initial tests have been completed to measure pressure drop versus flow rate for a prototypic core flow channel, with gas exiting to atmospheric pressure conditions. The experimental results of the completed DDG tests presented in this paper validate the predicted results to within a reasonable margin of error. These tests have resulted in amore » re-design of the flow annulus to reduce the pressure drop. Subsequent tests will be conducted with the re-designed flow channel and with the outlet pressure held at 150 psi (1 MPa). Design of a similar test for a nominal flow channel in the HPR heat exchanger (HPR-HX) has been completed and hardware is currently being assembled for testing this channel at 150 psi. When completed, these test programs will provide the data necessary to validate calculated flow performance for these reactor concepts (pressure drop and film temperature rise)« less

Effect of Marangoni Convection on Surfactant Transfer Between the Drop Connected to the Reservoir and Surrounding Liquid

NASA Astrophysics Data System (ADS)

Kostarev, K.; Denisova, M.; Shmyrov, A.

2018-03-01

The paper presents the results of comparative investigation of the interaction between the capillary and buoyant mechanisms of motion in a problem of surfactant mass transfer between an insoluble drop and surrounding fluid under different gravity conditions. The research was performed for the drop that is coupled with the reservoir filled with a source mixture through a long thin tube (needle). Visualization of the flow patterns and concentration fields has shown that surfactant diffusion from the needle at normal gravity leads to the onset of the oscillatory mode of the capillary convection in the drop. It has been found that the frequency of the Marangoni convection outbursts, the lifetime of the oscillatory flow modes and the amount of the source mixture involved in the process of mass transfer depend on the drop size and initial concentration of the surfactant. The obtained results are compared with the cases of surfactant diffusion from the isolated drop under terrestrial conditions and from the drop coupled with reservoir in microgravity. Additionally, a series of experiments were performed to investigate diffusion of a surfactant from the surrounding solution into a drop.

Exploration of the reasons for dropping out of psychotherapy: A qualitative study.

PubMed

Khazaie, Habibolah; Rezaie, Leeba; Shahdipour, Niloofar; Weaver, Patrick

2016-06-01

Elucidating the reasons for dropping out of psychotherapy can lead to the development of interventions aimed at reducing patient drop out. The present study aimed to explore patients' reasons for dropping out of psychotherapy in Kermanshah, Iran. The present qualitative study was performed using conventional content analysis. The current sample included 15 participants consisting of 7 patients who dropped out of psychotherapy and 8 psychotherapists who have previously experienced patient dropout. A semi-structured interview was used for data collection. All interviews were audio recorded and subsequently transcribed. Content analysis using constant comparisons was performed for transcribed interviews. Four main categories emerged as reasons for dropping out of psychotherapy: dissatisfaction with the quality of psychotherapy, financial problems in psychotherapy, unprepared socio-cultural context of psychotherapy, and psychotherapy as a non-user friendly treatment. Additionally, specific subcategories within each main category were documented. The results revealed distinct reasons for psychotherapy drop out in the current Iranian-based sample. These identified reasons should be considered and addressed at the onset of treatment as well as in the development of formal interventions aimed at reducing dropout. Further research investigating the antecedents leading to patient drop out is recommended. Copyright © 2016 Elsevier Ltd. All rights reserved.

A critical review of forced convection heat transfer and pressure drop of Al2O3, TiO2 and CuO nanofluids

NASA Astrophysics Data System (ADS)

Khurana, Deepak; Choudhary, Rajesh; Subudhi, Sudhakar

2017-01-01

Nanofluid is the colloidal suspension of nanosized solid particles like metals or metal oxides in some conventional fluids like water and ethylene glycol. Due to its unique characteristics of enhanced heat transfer compared to conventional fluid, it has attracted the attention of research community. The forced convection heat transfer of nanofluid is investigated by numerous researchers. This paper critically reviews the papers published on experimental studies of forced convection heat transfer and pressure drop of Al2O3, TiO2 and CuO based nanofluids dispersed in water, ethylene glycol and water-ethylene glycol mixture. Most of the researchers have shown a little rise in pressure drop with the use of nanofluids in plain tube. Literature has reported that the pumping power is appreciably high, only at very high particle concentration i.e. more than 5 %. As nanofluids are able to enhance the heat transfer at low particle concentrations so most of the researchers have used less than 3 % volume concentration in their studies. Almost no disagreement is observed on pressure drop results of different researchers. But there is not a common agreement in magnitude and mechanism of heat transfer enhancement. Few studies have shown an anomalous enhancement in heat transfer even at low particle concentration. On the contrary, some researchers have shown little heat transfer enhancement at the same particle concentration. A large variation (2-3 times) in Nusselt number was observed for few studies under similar conditions.

Climate warming may increase aphids' dropping probabilities in response to high temperatures.

PubMed

Ma, Gang; Ma, Chun-Sen

2012-11-01

Dropping off is considered an anti-predator behavior for aphids since previous studies have shown that it reduces the risk of predation. However, little attention is paid to dropping behavior triggered by other external stresses such as daytime high temperatures which are predicted to become more frequent in the context of climate warming. Here we defined a new parameter, drop-off temperature (DOT), to describe the critical temperature at which an aphid drops off its host plant when the ambient temperature increases gradually and slowly. Detailed studies were conducted to reveal effects of short-term acclimation (temperature, exposure time at high-temperature and starvation) on DOT of an aphid species, Sitobion avenae. Our objectives were to test if the aphids dropped off host plant to avoid high temperatures and how short-term acclimation affected the aphids' dropping behavior in response to heat stress. We suggest that dropping is a behavioral thermoregulation to avoid heat stress, since aphids started to move before they dropped off and the dropped aphids were still able to control their muscles prior to knockdown. The adults starved for 12 h had higher DOT values than those that were unstarved or starved for 6 h, and there was a trade-off between behavioral thermoregulation and energy acquisition. Higher temperatures and longer exposure times at high temperatures significantly lowered the aphids' DOT, suggested that the aphids avoid heat stress by dropping when exposed to high temperatures. Climate warming may therefore increase the aphids' dropping probabilities and consequently affect the aphids' individual development and population growth. Copyright © 2012 Elsevier Ltd. All rights reserved.

Munitions Test Area and Incendiary Drop Site, Site 36-2, Data Addendum, Phase 2.

DTIC Science & Technology

1988-09-01

MUNITIONS TEST AREA AND INCENDIARY DROP SITE (NI September 1988 Contract Number DAAK11-84-D-0016 | • (Version 3.1) Environmental Science And Engineering, Inc...SITE, September 1988 Contract Number DAAK11-84-D-0016 (Version 3.1)I PREPARED BY ENVIRONMENTAL SCIENCE AND ENGINEERING, INC. Harding Lawson Associates I...the Program Managers Office (PMO). Environmental Science and Engineering (ESE), Morrison-Knudsen Engineers (MKE), and Harding Lawson Associates (HLA

Investigation in Simulated Vertical Descent of the Characteristics of a Cargo-Dropping Device having Extensible Rotating Blades

NASA Technical Reports Server (NTRS)

Stone, Ralph W., Jr.; Hultz, Burton E.

1949-01-01

The characteristics of a cargo-dropping device having extensible rotating blades as load-carrying surfaces have been studied in simulated vertical descent in the Langley 20-foot free-spinning tunnel. The investigation included tests to determine the variation in vertical sinking speed with load. A study of the blade characteristics and of the test results indicated a method of dynamically balancing the blades to permit proper functioning of the device.

Effect of sweet orange aroma on experimental anxiety in humans.

PubMed

Goes, Tiago Costa; Antunes, Fabrício Dias; Alves, Péricles Barreto; Teixeira-Silva, Flavia

2012-08-01

The objective of this study was to evaluate the potential anxiolytic effect of sweet orange (Citrus sinensis) aroma in healthy volunteers submitted to an anxiogenic situation. Forty (40) male volunteers were allocated to five different groups for the inhalation of sweet orange essential oil (test aroma: 2.5, 5, or 10 drops), tea tree essential oil (control aroma: 2.5 drops), or water (nonaromatic control: 2.5 drops). Immediately after inhalation, each volunteer was submitted to a model of anxiety, the video-monitored version of the Stroop Color-Word Test (SCWT). Psychologic parameters (state-anxiety, subjective tension, tranquilization, and sedation) and physiologic parameters (heart rate and gastrocnemius electromyogram) were evaluated before the inhalation period and before, during, and after the SCWT. Unlike the control groups, the individuals exposed to the test aroma (2.5 and 10 drops) presented a lack of significant alterations (p>0.05) in state-anxiety, subjective tension and tranquillity levels throughout the anxiogenic situation, revealing an anxiolytic activity of sweet orange essential oil. Physiologic alterations along the test were not prevented in any treatment group, as has previously been observed for diazepam. Although more studies are needed to find out the clinical relevance of aromatherapy for anxiety disorders, the present results indicate an acute anxiolytic activity of sweet orange aroma, giving some scientific support to its use as a tranquilizer by aromatherapists.

A new class of high-G and long-duration shock testing machines

NASA Astrophysics Data System (ADS)

Rastegar, Jahangir

2018-03-01

Currently available methods and systems for testing components for survival and performance under shock loading suffer from several shortcomings for use to simulate high-G acceleration events with relatively long duration. Such events include most munitions firing and target impact, vehicular accidents, drops from relatively high heights, air drops, impact between machine components, and other similar events. In this paper, a new class of shock testing machines are presented that can be used to subject components to be tested to high-G acceleration pulses of prescribed amplitudes and relatively long durations. The machines provide for highly repeatable testing of components. The components are mounted on an open platform for ease of instrumentation and video recording of their dynamic behavior during shock loading tests.

DIME Students Waiting for Their Turn to Drop Experiment

NASA Technical Reports Server (NTRS)

2002-01-01

Students pause while waiting their turn at the 2.2-second Drop Tower during the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

DIME Students Discuss Final Drop Tower Experiment Design

NASA Technical Reports Server (NTRS)

2002-01-01

Students discuss fine points of their final design for the Drop Tower experiment during the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

ISDAC Microphysics

DOE Data Explorer

McFarquhar, Greg

2011-07-25

Best estimate of cloud microphysical parameters derived using data collected by the cloud microphysical probes installed on the National Research Council (NRC) of Canada Convair-580 during ISDAC. These files contain phase, liquid and ice crystal size distributions (Nw(D) and Ni(D) respectively), liquid water content (LWC), ice water content (IWC), extinction of liquid drops (bw), extinction of ice crystals (bi), effective radius of water drops (rew) and of ice crystals (rei) and median mass diameter of liquid drops (Dmml) and of ice crystals (Dmmi) at 30 second resolution.

DIME Participant Builds a Potential Drop Tower Candidate

NASA Technical Reports Server (NTRS)

2002-01-01

A student assembles a Lego (TM) Challenge device designed to operate in the portable drop tower demonstrator as part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

The Drop-Outs and the Dilatory on the Road to the Doctorate.

ERIC Educational Resources Information Center

Rudd, Ernest

1986-01-01

Results of a survey of British doctoral students not completing their graduate programs are reported. Students' reasons for dropping out include individual characteristics, personal problems and accidents, problems inherent in research projects, and poor supervision. Faculty attitudes and government policy are discussed. (MSE)

Final Technical Report: Electrohydrodynamic Tip Streaming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Basaran, Osman

2016-01-06

When subjected to strong electric fields, liquid drops and films form conical tips and emit thin jets from their tips. Such electrodydrodynamic (EDH) tip streaming or cone-jetting phenomena, which are sometimes referred to as electrospraying, occur widely in nature, e.g., in ejection of streams of small charged drops from pointed tips of raindrops in thunderclouds, and technology, e.g., in electrospray mass spectrometry or electric field-driven solvent extraction. More recently, EHD cone-jetting has emerged as a powerful technique for direct printing of solar cells, micro- and nano- particle production, and microencapsulation for controlled release. In many of the aforementioned situations, ofmore » equal importance to the processes by which one drop disintegrates to form several drops are those by which (a) two drops come together and coalesce and (b) two drops are coupled to form a double droplet system (DDS) or a capillary switch (CS). the main objective of this research program is to advance through simulation, theory, and experiment the breakup, coalescence, and oscillatory dynamics of single and pairs of charged as well as uncharged drops.« less

Distinguishing between microscale gaseous bubbles and liquid drops

NASA Astrophysics Data System (ADS)

Tan, Beng Hau; An, Hongjie; Chan, Chon U.; Ohl, Claus-Dieter

2015-11-01

In recent years, there has been strong research interest in decorating surfaces with tiny bubbles and drops due to their potential applications in reducing slippage in micro and nanofluidic devices. Both nanobubbles and nanodrops are typically nucleated by exchanging fluids over a suitable substrate. However, the nucleation experiments present many challenges, such as reproducibility and the possibility of contamination. The use of one-use plastic syringes and needle cannulas in nucleation experiments can introduce polymeric contamination. A contaminated experiment may nucleate bubbles, drops or both. Moreover, it is surprisingly difficult to distinguish between bubbles and drops under the usual atomic force microscopy or optical techniques. Here we present an experimental study comparing bubbles and oil (PDMS) drops on an atomically smooth surface (HOPG). Instead of nucleating the objects via solvent exchange, we directly introduced bubbles via electrolysis, and oil drops by injecting a dilute solution. Contrary to previous reports, we find that under careful AFM characterisation, liquid drops and gaseous bubbles respond differently to a change in imaging force, and moreover present different characteristic force curves.

Implementation of an axisymmetric drop shape apparatus using a Raspberry-Pi single-board computer and a web camera

NASA Astrophysics Data System (ADS)

Carlà, Marcello; Orlando, Antonio

2018-07-01

This paper describes the implementation of an axisymmetric drop shape apparatus for the measurement of surface or interfacial tension of a hanging liquid drop, using only cheap resources like a common web camera and a single-board microcomputer. The mechanics of the apparatus is composed of stubs of commonly available aluminium bar, with all other mechanical parts manufactured with an amateur 3D printer. All of the required software, either for handling the camera and taking the images, or for processing the drop images to get the drop profile and fit it with the Bashforth and Adams equation, is freely available under an open source license. Despite the very limited cost of the whole setup, an extensive test has demonstrated an overall accuracy of ±0.2% or better.

Water drop dynamics on a granular layer

NASA Astrophysics Data System (ADS)

Llorens, Coraline; Biance, Anne-Laure; Ybert, Christophe; Pirat, Christophe; Liquids; Interfaces Team

2015-11-01

Liquid drop impacts, either on a solid surface or a liquid bath, have been studied for a while and are still subject of intense research. Less is known concerning impacts on granular layers that are shown to exhibit an intermediate situation between solid and liquid. In this study, we focus on water drop impacts on granular matter made of micrometer-sized spherical glass beads. In particular, we investigate the overall dynamics arising from the interplay between liquid and grains throughout the impact. Depending on the relevant parameters (impact velocity, drop and grain sizes, as well as their wetting properties), various behaviors are evidenced. In particular, the behavior of the beads at the liquid-gas interface (ball-bearing vs imbibition) is shown to greatly affect the spreading dynamics of the drop, as well as satellite droplets formation, beads ejection, and the final crater morphology.

Reusable Material for Drop Tower

DTIC Science & Technology

2011-08-01

R3 Buna-N Rubber ............................................................................................... 32 B-3. R5 EPDM Rubber ...Butyl Rubber . Figure B-2. R3 Buna-N Rubber . Figure B-3. R5 EPDM Rubber . Figure B-4. R6 Gel Rubber . UNCLASSIFIED 33...11 Current Drop Tower Material & Setup .......................................................... 11 Bowling Ball Rubber Material Sample Test

Dropping fire retardants by helicopter: tests of three new helitanks

Treesearch

James B. Davis

1963-01-01

Late model helicopters equipped with new helitanks and adequately supplied can accurately deliver as much fire retardant as most fixed-wing air tankers at a potentially lower cost. Viscous water dropped from helicopters clung to fuel surfaces and was concentrated in a narrower pattern than plain water.

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

NASA Technical Reports Server (NTRS)

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

2011-01-01

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

Experimental comparison of icing cloud instruments

NASA Technical Reports Server (NTRS)

Olsen, W.; Takeuchi, D. M.; Adams, K.

1983-01-01

Icing cloud instruments were tested in the spray cloud Icing Research Tunnel (IRT) in order to determine their relative accuracy and their limitations over a broad range of conditions. It was found that the average of the readings from each of the liquid water content (LWC) instruments tested agreed closely with each other and with the IRT calibration; but all have a data scatter (+ or - one standard deviation) of about + or - 20 percent. The effect of this + or - 20 percent uncertainty is probably acceptable in aero-penalty and deicer experiments. Existing laser spectrometers proved to be too inaccurate for LWC measurements. The error due to water runoff was the same for all ice accretion LWC instruments. Any given laser spectrometer proved to be highly repeatable in its indications of volume median drop size (DVM), LWC and drop size distribution. However, there was a significant disagreement between different spectrometers of the same model, even after careful standard calibration and data analysis. The scatter about the mean of the DVM data from five Axial Scattering Spectrometer Probes was + or - 20 percent (+ or - one standard deviation) and the average was 20 percent higher than the old IRT calibration. The + or - 20 percent uncertainty in DVM can cause an unacceptable variation in the drag coefficient of an airfoil with ice; however, the variation in a deicer performance test may be acceptable.

Alaskan frozen soil impact tests of the B83-C/S and Strategic Earth Penetrator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dockery, H.A.; Clarke, J.B.; Stull, S.P.

To assess the penetrability of the B83 strategic bomb and a Strategic Earth Penetrator design into frozen soil and ice, Lawrence Livermore National Laboratory and Sandia National Laboratories, assisted by the US Air Force and US Army, conducted a series of tests in 1987. In April, Strategic Earth Penetrator units were dropped into multi-year sea ice and frozen tundra near Prudhoe Bay, Alaska. Calculated impact velocity ranged from 200 to 308 ft/s into ice and from 200 to 444 ft/s into frozen tundra. Tests in May include drops of a B83 design with specially designed ogive nose shape, a B83more » with a cap over the production ''cookie cutter'' nose, and a Strategic Earth Penetrator. The May tests were conducted near Fairbanks, Alaska, at Eielson Air Force Base and at Donnelly Flats on the Fort Greely Military Reservation. The type of frozen soil encountered at Eielson was very homogeneous in composition; however. Two drops impacted areas with very thin frozen soil layers at depths of about 24 in. below the surface. Velocities of these drops prior to impact ranged from 256 to 308 ft/s, and peak axial deceleration ranged from 160 to 490 g. The units penetrated to depths of 7.5-12 ft. Three other events impacted in a target area where frozen soil averaging 35 in. thick extended essentially to the surface. We calculated velocities prior to impact at 200-256 ft/s; and penetration depths of 3.2-9.6 ft. The geologic material at Donnelly Flats was primarily a very hard, rocky glacial deposit with a variable degree of ice bonding. Here, the test units dropped from 10,000 ft above ground level and achieved an average calculated velocity of 802 ft/s. Depth of penetration ranged from 7.6 to 13.5 ft.« less

AREVA Team Develops Sump Strainer Blockage Solution for PWRs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phan, Ray

2006-07-01

The purpose of this paper is to discuss the methodology, testing challenges, and results of testing that a team of experts from Areva NP, Alden Research Laboratory, Inc (ALDEN), and Performance Contracting Inc. (PCI) has developed. The team is currently implementing a comprehensive solution to the issue of Emergency Core Cooling System (ECCS) sump strainer blockage facing Pressurized Water Reactor (PWR) Nuclear Plants. The team has successfully demonstrated two key results from the testing of passive Sure-FlowTM strainers, which were designed to distribute the required flow over a large surface area resulting in extremely low approach velocities. First, the actualmore » head loss (pressure drop) as tested, across the prototype strainers, was much lower than the calculated head loss using the Nuclear Regulatory Commission (NRC) approved NUREG/CR-6224 head loss correlation. Second, the penetration fractions were much lower than those seen in the NRC sponsored debris penetration tests. (author)« less

Sand Impact Tests of a Half-Scale Crew Module Boilerplate Test Article

NASA Technical Reports Server (NTRS)

Vassilakos, Gregory J.; Hardy, Robin C.

2012-01-01

Although the Orion Multi-Purpose Crew Vehicle (MPCV) is being designed primarily for water landings, a further investigation of launch abort scenarios reveals the possibility of an onshore landing at Kennedy Space Center (KSC). To gather data for correlation against simulations of beach landing impacts, a series of sand impact tests were conducted at NASA Langley Research Center (LaRC). Both vertical drop tests and swing tests with combined vertical and horizontal velocity were performed onto beds of common construction-grade sand using a geometrically scaled crew module boilerplate test article. The tests were simulated using the explicit, nonlinear, transient dynamic finite element code LS-DYNA. The material models for the sand utilized in the simulations were based on tests of sand specimens. Although the LSDYNA models provided reasonable predictions for peak accelerations, they were not always able to track the response through the duration of the impact. Further improvements to the material model used for the sand were identified based on results from the sand specimen tests.

Crop Production for Advanced Life Support Systems - Observations From the Kennedy Space Center Breadboard Project

NASA Technical Reports Server (NTRS)

Wheeler, R. M.; Sager, J. C.; Prince, R. P.; Knott, W. M.; Mackowiak, C. L.; Stutte, G. W.; Yorio, N. C.; Ruffe, L. M.; Peterson, B. V.; Goins, G. D.

2003-01-01

The use of plants for bioregenerative life support for space missions was first studied by the US Air Force in the 1950s and 1960s. Extensive testing was also conducted from the 1960s through the 1980s by Russian researchers located at the Institute of Biophysics in Krasnoyarsk, Siberia, and the Institute for Biomedical Problems in Moscow. NASA initiated bioregenerative research in the 1960s (e.g., Hydrogenomonas) but this research did not include testing with plants until about 1980, with the start of the Controlled Ecological Life Support System (CELSS) Program. The NASA CELSS research was carried out at universities, private corporations, and NASA field centers, including Kennedy Space Center (KSC). The project at KSC began in 1985 and was called the CELSS Breadboard Project to indicate the capability for plugging in and testing various life support technologies; this name has since been dropped but bioregenerative testing at KSC has continued to the present under the NASA s Advanced Life Support (ALS) Program. A primary objective of the KSC testing was to conduct pre-integration tests with plants (crops) in a large, atmospherically closed test chamber called the Biomass Production Chamber (BPC). Test protocols for the BPC were based on observations and growing procedures developed by university investigators, as well as procedures developed in plant growth chamber studies at KSC. Growth chamber studies to support BPC testing focused on plant responses to different carbon dioxide (CO2) concentrations, different spectral qualities from various electric lamps, and nutrient film hydroponic culture techniques.